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1.  Toll-Like Receptor 2 Impairs Host Defense in Gram-Negative Sepsis Caused by Burkholderia pseudomallei (Melioidosis) 
PLoS Medicine  2007;4(7):e248.
Toll-like receptors (TLRs) are essential in host defense against pathogens by virtue of their capacity to detect microbes and initiate the immune response. TLR2 is seen as the most important receptor for gram-positive bacteria, while TLR4 is regarded as the gram-negative TLR. Melioidosis is a severe infection caused by the gram-negative bacterium, Burkholderia pseudomallei, that is endemic in Southeast Asia. We aimed to characterize the expression and function of TLRs in septic melioidosis.
Methods and Findings
Patient studies: 34 patients with melioidosis demonstrated increased expression of CD14, TLR1, TLR2, and TLR4 on the cell surfaces of monocytes and granulocytes, and increased CD14, TLR1, TLR2, TLR4, LY96 (also known as MD-2), TLR5, and TLR10 mRNA levels in purified monocytes and granulocytes when compared with healthy controls. In vitro experiments: Whole-blood and alveolar macrophages obtained from TLR2 and TLR4 knockout (KO) mice were less responsive to B. pseudomallei in vitro, whereas in the reverse experiment, transfection of HEK293 cells with either TLR2 or TLR4 rendered these cells responsive to this bacterium. In addition, the lipopolysaccharide (LPS) of B. pseudomallei signals through TLR2 and not through TLR4. Mouse studies: Surprisingly, TLR4 KO mice were indistinguishable from wild-type mice with respect to bacterial outgrowth and survival in experimentally induced melioidosis. In contrast, TLR2 KO mice displayed a markedly improved host defenses as reflected by a strong survival advantage together with decreased bacterial loads, reduced lung inflammation, and less distant-organ injury.
Patients with melioidosis displayed an up-regulation of multiple TLRs in peripheral blood monocytes and granulocytes. Although both TLR2 and TLR4 contribute to cellular responsiveness to B. pseudomallei in vitro, TLR2 detects the LPS of B. pseudomallei, and only TLR2 impacts on the immune response of the intact host in vivo. Inhibition of TLR2 may be a novel treatment strategy in melioidosis.
Willem Wiersinga and colleagues find up-regulation of multiple Toll-like receptors (TLRs) in peripheral blood cells of patients with melioidosis. However, only TLR2 had an effect on the immune response in a mouse model.
Editors' Summary
Melioidosis is a severe tropical infection caused by the bacterium Burkholderia pseudomallei. This soil-dwelling pathogen (disease-causing organism) enters the body through cuts, by swallowed contaminated water, or by inhaled contaminated dust. Here, it can cause a severe lung infection or spread into the blood stream and around the body, where it causes widespread inflammation (sepsis) and organ failure. Untreated septic melioidosis is usually fatal. Even with antibiotic therapy, half the people who develop it in Thailand (a hot spot for melioidosis) die. B. pseudomallei is a “gram-negative” bacterium. That is, it is surrounded by a membrane that stops it taking up a stain used to detect bacteria. This membrane contains a molecule called lipopolysaccharide (LPS). Proteins on immune system cells called Toll-like receptors (TLRs), of which there are many, recognize LPS and other surface molecules common to different pathogens and tell the cells to make cytokines. These cytokines stimulate the immune system to kill the pathogen but also cause inflammation, the underlying problem in septic melioidosis and other forms of sepsis. In other words, TLRs are two-edged swords—they provide an essential first-line defense against pathogens, but cause life-threatening inflammation if overstimulated.
Why Was This Study Done?
It isn't known which TLRs are involved in melioidosis. TLR4 normally detects LPS, but the surface of B. pseudomallei also carries molecules that interact with TLR2. Understanding how B. pseudomallei interacts with TLRs might suggest new, more effective ways to treat septic melioidosis. Better remedies for this disease are badly needed because, as well as the infections it causes in the community, the US Centers for Disease Control and Prevention has identified B. pseudomallei as a potential bioterrorism agent. In this study, the researchers have characterized the expression and function of TLRs in septic melioidosis using human, in vitro (test tube), and animal approaches.
What Did the Researchers Do and Find?
The researchers isolated monocytes and granulocytes (immune system cells involved in first-line defenses against pathogens) from patients with melioidosis and from healthy people. The patients' cells made more TLR1, TLR2, TLR4, and CD14 (a protein that enhances the activation of immune system cells by LPS) than those of the healthy controls and more of the mRNAs encoding several other TLRs. Next, the researchers tested the ability of heat-killed B. pseudomallei to induce the release of TNFα (a cytokine produced in response to TLR signaling) from macrophages (immune system cells that swallow up pathogens) isolated from wild-type mice and from mice lacking TLR2 or TLR4. Macrophages isolated from wild-type mice made more TNFα than those from TLR2- or TLR4-deficient mice. In addition, a human kidney cell line engineered to express CD14/TLR2 or CD14/TLR4 but not the parent cell line released IL8 (another cytokine) when stimulated with heat-killed B. pseudomallei. Other experiments in these human cell lines showed that LPS purified from B. pseudomallei signals through TLR2 but not through TLR4. Finally, the researchers tested the ability of TLR2- and TLR4-deficient mice to survive after infection with live B. pseudomallei. Compared with TLR4-deficient or wild-type mice, the TLR2-deficient mice had a strong survival advantage, a lower bacterial load, reduced lung inflammation, and less organ damage.
What Do These Findings Mean?
These findings show that people with melioidosis have increased expression of several TLRs, any one of which might cause the sepsis associated with B. pseudomallei infection. The in vitro findings indicate that TLR2 and TLR4 both contribute to the responsiveness of immune cells to B. pseudomallei in test tubes, but that only TLR2 detects the LPS of this bacterium. This unexpected result—TLR4 normally responds to LPS—might indicate that there is something unique about the LPS of B. pseudomallei. Finally, the survival of TLR2-deficient mice after infection with B. pseudomallei suggests that TLR2-mediated dysregulation of the immune system in response to invasive B. pseudomallei might cause septic melioidosis. Although these results need confirming in people, they suggest that inhibition of TLR2 in combination with antibiotic therapy might improve outcomes for people with melioidosis.
Additional Information.
Please access these Web sites via the online version of this summary at
Information is available from the US Centers for Disease Control and Prevention on melioidosis (in English and Spanish)
The UK Health Protection Agency provides information for the public and health professionals on melioidosis
Wikipedia has pages on melioidosis and on Toll-like receptors (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The MedlinePlus encyclopedia contains a page on sepsis (in English and Spanish)
PMCID: PMC1950213  PMID: 17676990
2.  The Concentrations of Ambient Burkholderia Pseudomallei during Typhoon Season in Endemic Area of Melioidosis in Taiwan 
Melioidosis is a severe bacterial infection caused by Burkholderia pseudomallei with a high case-fatality rate. Epidemiological and animal studies show the possibility of inhalation transmission. However, no B. pseudomallei concentrations in ambient air have been researched. Here, we developed a method to quantify ambient B. pseudomallei and then measured concentrations of ambient B. pseudomallei during the typhoon season and the non-typhoon season to determine the factors influencing ambient B. pseudomallei levels.
We quantified ambient B. pseudomallei by using a filter/real-time qPCR method in the Zoynan Region in Kaohsiung, southern Taiwan. Twenty-four hour samples were collected at a sampling rate of 20 L/min every day from June 11 to December 21, 2012 including during the typhoon season (June to September) and reference season (October to December).
We successfully developed a filtration/real-time qPCR method to quantify ambient B. pseudomallei. To our knowledge, this is the first report describing concentrations of ambient B. pseudomallei. Ambient B. pseudomallei were only detected during the typhoon season when compared to the reference season. For the typhoons affecting the Zoynan Region, the positive rates of ambient B. pseudomallei were very high at 80% to 100%. During June to December, rainfall was positively correlated with ambient B. pseudomallei with a statistical significance. Sediment at a nearby pond significantly influenced the concentration of ambient B. pseudomallei. During the typhoon month, the typhoon was positively correlated with ambient B. pseudomallei whereas wind speed was reversely correlated with ambient B. pseudomallei.
Our data suggest the possibility of transmission of B. pseudomallei via inhalation during the typhoon season.
Author Summary
Melioidosis is a severe bacterial infection caused by Burkholderia pseudomallei with a high case-fatality rate. Epidemiological and animal studies show the possibility of inhalation transmission. However, no B. pseudomallei concentrations in ambient air have been researched. Here, we successfully developed a method to quantify ambient B. pseudomallei by using a filter/real-time qPCR method. Twenty-four hour samples were collected every day from June 11 to December 21, 2012 including during the typhoon season (June to September) and reference season (October to December) in the Zoynan Region in Kaohsiung, southern Taiwan. To our knowledge, this is the first report describing concentrations of B. pseudomallei in ambient air. For the typhoons affecting the Zoynan Region, the positive rates of ambient B. pseudomallei were very high. Our data imply the possibility of air transmission of Melioidosis during the typhoon season. In addition, ambient B. pseudomallei aerosolized from sediment of a nearby lake should be a concern as an important source of transmission. Our results could provide deeper insight into Melioidosis transmissibility and infection control.
PMCID: PMC4038478  PMID: 24874950
3.  Traumatic Extradural Hematoma in Enugu, Nigeria 
Acute traumatic extradural hematoma (EDH) is life threatening and requires prompt intervention. This is a study of incidence and outcome of consecutive patients with EDH managed in Enugu, Nigeria against a background of delayed referral.
Materials and Methods:
We retrospectively examined all consecutive trauma cases managed between 2003 and 2009 and analyzed patients with acute traumatic extradural hematoma in isolation or in combination with other intra cranial lesions. Age, sex, cause of injury, time of presentation, Glasgow Coma Score (GCS), pupil reactivity, treatment and clinical outcomes were determined.
Of 817 head injuries, 69 (8.4%) had EDH, a mean of 9.9 patients per year. Males were 57 (83%) and females 12 (17%). Peak age incidences were the second and third decades of life, with a mean age of 30.2 years. Causes were road traffic accidents (57%), assault (22%) and falls (9%). Twenty-six (38%) patients presented within 24 h of injury and only one patient presented within 4 h. The average time lag before presentation was 94.2 h. At presentation 39% had GCS of 13-15, 27% had 9-12 and 34% had 3-8. The most common location of hematoma was temporal (27.5%). Forty (59%) patients had surgery while 14 (20%) were managed conservatively. Ten patients (14.5%) died and of these 70% had GCS <8 and 60% had a seizure.
We conclude that early appropriate treatment of EDH results in good high quality survival (Glasgow Outcome Score 4 or 5). Low GCS should not be an absolute contraindication for surgery. Seizure prophylaxis should be considered in patients with GCS <8.
PMCID: PMC3762009  PMID: 24027399
Demography; extradural hematoma; head injury; outcome
4.  Melioidosis presenting with mediastinal lymphadenopathy masquerading as malignancy: a case report 
Melioidosis, endemic in Thailand and in the Northern Territory of Australia is an emerging infectious disease in India which can present with varied forms. A case of melioidosis, presenting as a rare anterior mediastinal mass which can masquerade as malignancy or tuberculosis, is described here. With treatment, our patient initially showed an increase in the size of mediastinal node and development of new submandibular node.. To the best of our knowledge, this phenomenon has not been documented in the literature and the same is highlighted in this case report.
Case Presentation
A 43-year-old Asian man with diabetes presented with fever, loss of appetite, weight loss for one month and painful swelling below his left mandible for five days. An examination revealed an enlarged left submandibular lymph node and bilateral axillary lymph nodes. A chest X-ray showed mediastinal widening. Computed tomography of his thorax showed a lobulated heterogeneously enhancing anterior mediastinal mass encasing the superior vena cava suggestive of malignancy. An excision biopsy of the lymph node showed granulomas suggestive of tuberculosis but bone marrow culture and lymph node aspirate culture grew Burkholderia pseudomallei. He was treated with parenteral ceftazidime and amoxicillin-clavulanic acid. During the course of treatment, he developed an enlargement of the submandibular lymph node on the opposite side. It gradually subsided with the continuation of therapy orally with a combination of cotrimoxazole and doxycycline for six months. A repeat computed tomography chest scan showed resolution of the mediastinal mass.
Melioidosis can present as a mediastinal mass that mimics tuberculosis or malignancy. During the initial phase of treatment of melioidosis, the appearance of new lymph nodes or an increase in the size of the existing lymph nodes does not mean treatment failure. Inexperienced clinicians may consider this as treatment failure and may switch treatment. To the best of our knowledge, this is the first report documenting this phenomenon in melioidosis cases.
PMCID: PMC3295726  PMID: 22269609
melioidosis; mediastinal mass; lymphadenopathy; malignancy; tuberculosis
5.  Subcutaneous Surprise 
Melioidosis is a zoonosis caused by the accidental pathogen Burkholderia pseudomallei, which is endemic in Southeast Asia and northern Australia. The mortality of melioidosis is 20-50% even with treatment. Suppurative lymphadenitis caused by melioidosis has been rarely encountered by clinicians practicing in endemic areas. In the majority of previously described patients, the infected lymph nodes were in the head and neck region, except for four patients who presented with unilateral, inguinal lymphadenitis. Hence, we report a case of unilateral suppurative inguinal lymphadenitis caused by B. pseudomallei in a 48-year-old lady who presented with groin swelling of 2 months duration.
PMCID: PMC3952283  PMID: 24669344
Burkholderia pseudomallei; Inguinal Lymphadenitis; Melioidosis
6.  Transverse myelitis secondary to Melioidosis; A case report 
BMC Infectious Diseases  2012;12:232.
Melioidosis has become an emerging infection in Sri Lanka; a country which is considered non endemic for it. Paraplegia due to Burkholderia pseudomallei is a very rare entity encountered even in countries where the disease is endemic. There are no reported cases of transverse myelitis due to melioidosis in Sri Lankan population thus we report the first case.
Case presentation
A 21 year old farmer presented with sudden onset bi lateral lower limb weakness, numbness and urine retention. Examination revealed flaccid areflexic lower limbs with a sensory loss of all modalities and a sensory level at T10 together with sphincter involvement. MRI of the thoracolumbar spine showed extensive myelitis of the thoracic spine complicating left psoas abscess without definite extension to the spinal cord or cord compression. Burkholderia pseudomallei was isolated from the psoas abscess pus cultures and the diagnosis of melioidosis was confirmed with high titers of Burkholderia pseudomallei antibodies and positive PCR. He was treated with high doses of IV ceftazidime and oral cotrimoxazole for one month with a plan to continue cotrimoxazole and doxycycline till one year. Patient’s general condition improved but the residual neurological problems persisted.
The exact pathogenesis of spinal cord melioidosis is not quite certain except in the cases where there is direct microbial invasion, which does not appear to be the case in our patient. We postulate our patient’s presentation could be due to ischemia of the spinal cord following septic embolisation or thrombosis of spinal artery due to the abscess nearby. A neurotrophic exotoxin causing myelitis or post infectious immunological demyelination is yet another possibility. This emphasizes the necessity of further studies to elucidate the exact pathogenesis in this type of presentations.
Health care professionals in Sri Lanka, where this is an emerging infection, need to improve their knowledge regarding this disease and should have high degree of suspicion to make a correct and a timely diagnosis to reduce the morbidity and mortality due to Burkholderia pseudomallei infection. It is highly likely that this infection is under diagnosed in developing countries where diagnostic facilities are minimal. Therefore strategies to improve the awareness and upgrade the diagnostic facilities need to be implemented in near future.
PMCID: PMC3511196  PMID: 23020820
Melioidosis; Transverse myelitis; Burkholderia pseudomallei; Flaccid paraplegia; Psoas abscess
7.  The frequency and consequences of head injury in epileptic seizures. 
The frequency and sequelae of head injury in epileptic seizures were assessed. Two hundred and fifty five resident patients with chronic long term epilepsy (165M, 90F) of average age 54 years were studied for a year and 43 patients in a short term assessment unit (22M, 21F) of average age 26 years were studied for a month. A total of 27,934 seizures were recorded, of which 12,626 (45.2%) were associated with falls. There were 766 significant head injuries. Four hundred and twenty two required simple dressing and observation, and 341 required sutures (average number of sutures 4.5). There was one confirmed skull fracture, one confirmed extradural haemorrhage and one confirmed subdural haemorrhage. Thus 2.7% of all seizures resulted in a head injury (6.1% of seizures associated with falling). Simple dressing was required in 1.5%; 1.2% required sutures. Only one in every 9311 seizures (one in every 4208 seizures associated with falls) resulted in skull fracture, extradural or subdural haemorrhage. Minor seizure related head injury is therefore relatively common, while severe head injury is rare.
PMCID: PMC1032184  PMID: 2732739
8.  Avascular necrosis of humeral head in an elderly patient with tuberculosis: a case report 
Osteonecrosis (avascular necrosis) is known to be caused by high-dose corticosteroid therapy, alcoholism and rarely by infections. However, a tubercular etiology of this condition is very rare. A review of the literature yielded only a few cases of polyarticular tuberculosis with osteonecrosis in immunosuppressed individuals. No case of monoarticular tubercular osteonecrosis diagnosed by aspiration cytology was found. Since tuberculosis is a curable disease, an early and accurate diagnosis is essential.
Case presentation
A 60-year-old Indian man presented with diffuse swelling and pain in the left shoulder for the previous 6 months. A computed tomography scan of the left shoulder revealed crescentic lucency in the humeral head, suggestive of osteonecrosis. Fine needle aspiration cytology smears from the swelling showed features of an acute suppurative lesion. Stain for acid-fast bacillus was positive and thus, a final clinico-pathological diagnosis of osteonecrosis of humeral head with tubercular etiology was rendered. The patient was initiated on anti-tuberculous therapy with symptomatic improvement in his condition.
Osteonecrosis, a debilitating disease, may rarely occur due to tuberculosis, especially in endemic areas. Fine needle aspiration cytology is an effective and inexpensive modality for an early diagnosis of the tubercular etiology of osteonecrosis.
PMCID: PMC2612682  PMID: 19055793
9.  Posttraumatic Giant Extradural Intradiploic Epidermoid Cysts of Posterior Cranial Fossa : Case Report and Review of the Literature 
We reported a unique case of posttraumatic giant infratentorial extradural intradiploic epidermoid cyst. A 54-year-old male, with a previous history of an open scalp injury and underlying linear skull fracture in the left occipital region in childhood, presented with a painful subcutaneous swelling, which had been developed gradually in the same region and moderate headache, nausea, vomiting and cerebellar ataxia. The duration of symptoms on admission was 3 months. Imaging studies revealed occipital bone destruction and giant extradural intradiploic lesion. The preoperative diagnosis was giant infratentorial extradural intradiploic epidermoid cyst. Surgery achieved total removal of the lesion, which was histologically confirmed and the postoperative course was uneventful. To our knowledge, this is the first case of giant infratentorial extradural intradiploic epidermoid cyst with a traumatic etiology described in the literature.
PMCID: PMC3070896  PMID: 21494364
Neoplasm; Epidermoid cyst; Cranial fossa; Posterior; Trauma; Etiology
10.  Within-Host Evolution of Burkholderia pseudomallei over a Twelve-Year Chronic Carriage Infection 
mBio  2013;4(4):e00388-13.
Burkholderia pseudomallei causes the potentially fatal disease melioidosis. It is generally accepted that B. pseudomallei is a noncommensal bacterium and that any culture-positive clinical specimen denotes disease requiring treatment. Over a 23-year study of melioidosis cases in Darwin, Australia, just one patient from 707 survivors has developed persistent asymptomatic B. pseudomallei carriage. To better understand the mechanisms behind this unique scenario, we performed whole-genome analysis of two strains isolated 139 months apart. During this period, B. pseudomallei underwent several adaptive changes. Of 23 point mutations, 78% were nonsynonymous and 43% were predicted to be deleterious to gene function, demonstrating a strong propensity for positive selection. Notably, a nonsense mutation inactivated the universal stress response sigma factor RpoS, with pleiotropic implications. The genome underwent substantial reduction, with four deletions in chromosome 2 resulting in the loss of 221 genes. The deleted loci included genes involved in secondary metabolism, environmental survival, and pathogenesis. Of 14 indels, 11 occurred in coding regions and 9 resulted in frameshift mutations that dramatically affected predicted gene products. Disproportionately, four indels affected lipopolysaccharide biosynthesis and modification. Finally, we identified a frameshift mutation in both P314 isolates within wcbR, an important component of the capsular polysaccharide I locus, suggesting virulence attenuation early in infection. Our study illustrates a unique clinical case that contrasts a high-consequence infectious agent with a long-term commensal infection and provides further insights into bacterial evolution within the human host.
Some bacterial pathogens establish long-term infections that are difficult or impossible to eradicate with current treatments. Rapid advances in genome sequencing technologies provide a powerful tool for understanding bacterial persistence within the human host. Burkholderia pseudomallei is considered a highly pathogenic bacterium because infection is commonly fatal. Here, we document within-host evolution of B. pseudomallei in a unique case of human infection with ongoing chronic carriage. Genomic comparison of isolates obtained 139 months (11.5 years) apart showed a strong signal of adaptation within the human host, including inactivation of virulence and immunogenic factors, and deletion of pathways involved in environmental survival. Two global regulatory genes were mutated in the 139-month isolate, indicating extensive regulatory changes favoring bacterial persistence. Our study provides insights into B. pseudomallei pathogenesis and, more broadly, identifies parallel evolutionary mechanisms that underlie chronic persistence of all bacterial pathogens.
PMCID: PMC3735121  PMID: 23860767
11.  Burkholderia pseudomallei Penetrates the Brain via Destruction of the Olfactory and Trigeminal Nerves: Implications for the Pathogenesis of Neurological Melioidosis 
mBio  2014;5(2):e00025-14.
Melioidosis is a potentially fatal disease that is endemic to tropical northern Australia and Southeast Asia, with a mortality rate of 14 to 50%. The bacterium Burkholderia pseudomallei is the causative agent which infects numerous parts of the human body, including the brain, which results in the neurological manifestation of melioidosis. The olfactory nerve constitutes a direct conduit from the nasal cavity into the brain, and we have previously reported that B. pseudomallei can colonize this nerve in mice. We have now investigated in detail the mechanism by which the bacteria penetrate the olfactory and trigeminal nerves within the nasal cavity and infect the brain. We found that the olfactory epithelium responded to intranasal B. pseudomallei infection by widespread crenellation followed by disintegration of the neuronal layer to expose the underlying basal layer, which the bacteria then colonized. With the loss of the neuronal cell bodies, olfactory axons also degenerated, and the bacteria then migrated through the now-open conduit of the olfactory nerves. Using immunohistochemistry, we demonstrated that B. pseudomallei migrated through the cribriform plate via the olfactory nerves to enter the outer layer of the olfactory bulb in the brain within 24 h. We also found that the bacteria colonized the thin respiratory epithelium in the nasal cavity and then rapidly migrated along the underlying trigeminal nerve to penetrate the cranial cavity. These results demonstrate that B. pseudomallei invasion of the nerves of the nasal cavity leads to direct infection of the brain and bypasses the blood-brain barrier.
Melioidosis is a potentially fatal tropical disease that is endemic to northern Australia and Southeast Asia. It is caused by the bacterium Burkholderia pseudomallei, which can infect many organs of the body, including the brain, and results in neurological symptoms. The pathway by which the bacteria can penetrate the brain is unknown, and we have investigated the ability of the bacteria to migrate along nerves that innervate the nasal cavity and enter the frontal region of the brain by using a mouse model of infection. By generating a mutant strain of B. pseudomallei which is unable to survive in the blood, we show that the bacteria rapidly penetrate the cranial cavity using the olfactory (smell) nerve and the trigeminal (sensory) nerve that line the nasal cavity.
PMCID: PMC3993850  PMID: 24736221
12.  Influence of age and fall type on head injuries in infants and toddlers 
Age-based differences in fall type and neuroanatomy in infants and toddlers may affect clinical presentations and injury patterns.
Our goal is to understand the influence of fall type and age on injuries to help guide clinical evaluation.
Retrospectively, 285 children 0–48 months with accidental head injury from a fall and brain imaging between 2000–2006 were categorized by age (infant=<1 year and toddler=1–4 years) and fall type: low (≤3 ft), intermediate (>3 and <10 ft), high height falls (≥10 ft) and stair falls.
Outcome Measures
Clinical manifestations were noted and head injuries separated into primary (bleeding) and secondary (hypoxia, edema). The influence of age and fall type on head injuries sustained was evaluated.
Injury patterns in children <4 yrs varied with age. Despite similar injury severity scores, infants sustained more skull fractures than toddlers (71% v. 39%). Of children with skull fractures, 11% had no evidence of scalp/facial soft tissue swelling. Of the patients with primary intracranial injury, 30% had no skull fracture and 8% had neither skull fracture nor cranial soft tissue injury. Low height falls resulted in primary intracranial injury without soft tissue or skull injury in infants (6%) and toddlers (16%).
Within a given fall type, age-related differences in injuries exist between infants and toddlers. When interpreting a fall history, clinicians must consider the fall type and influence of age on resulting injury. For young children, intracranial injury is not always accompanied by external manifestations of their injury.
PMCID: PMC3288448  PMID: 22079853
falls; brain injury; mechanism; age
13.  Molecular Investigations of a Locally Acquired Case of Melioidosis in Southern AZ, USA 
Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted several molecular genotyping procedures, including multi-locus sequence typing, SNP-profiling, and whole genome sequence typing. Each technique has different molecular epidemiologic advantages, all of which provided evidence that the infecting strain was most similar to those found in Southeast Asia, possibly originating in, or around, Malaysia. Advancements in new typing technologies provide genotyping resolution not previously available to public health investigators, allowing for more accurate source identification.
Author Summary
Melioidosis is a bacterial disease caused by percutaneous inoculation, aspiration or ingestion of the soil bacteria Burkholderia pseudomallei. Melioidosis is primarily found in Southeast Asia and Northern Australia, and, to a lesser degree, nearby regions. A recent case of melioidosis in Southwestern United States (Southern Arizona) prompted a detailed epidemiological and molecular investigation to discover the source of infection. The authors describe the use of multiple genomic analysis tools to aid in this investigation. The results of these analyses uniformly identified Southeast Asia as the source of the strain that infected the patient, however the epidemiological investigation had determined the patient had no international travel or known exposures to Southeast Asian products. New cutting edge technologies, such as next generation sequencing, are quickly being adapted into epidemiologic investigations, particularly for cases and outbreaks of unknown origin, although older, mature technologies with larger existing databases will still be needed for appropriate comparative analyses.
PMCID: PMC3196475  PMID: 22028940
14.  Primary Extradural Meningioma Presenting as Frontal Sinusitis with Extensive Bony Changes 
Primary extradural meningiomas are rare tumours and calvarial meningiomas with extensive bony changes and frontal sinusitis are rarer still. We report a 40-year-old female patient who presented to the otorhinolaryngologist at the Sultan Qaboos University Hospital in Muscat, Oman, in October 2013 with headaches and frontal swelling. She was diagnosed with frontal sinusitis complicated by osteomyelitis. Further clinical examination and imaging revealed a left frontal calvarial meningioma with extensive bony changes and extracalvarial extension into the frontal sinus. She underwent a left frontal craniotomy during which the tumour was removed. The postoperative period was uneventful and a follow-up computed tomography scan after three months showed only postoperative changes. This report discusses the radiological differential diagnosis and management of this type of lesion.
PMCID: PMC4205072  PMID: 25364563
Meningioma; Calvarial Hyperostosis; Neoplasm Invasiveness; Case Report; Oman
15.  Burkholderia pseudomallei Known Siderophores and Hemin Uptake Are Dispensable for Lethal Murine Melioidosis 
Burkholderia pseudomallei is a mostly saprophytic bacterium, but can infect humans where it causes the difficult-to-manage disease melioidosis. Even with proper diagnosis and prompt therapeutic interventions mortality rates still range from >20% in Northern Australia to over 40% in Thailand. Surprisingly little is yet known about how B. pseudomallei infects, invades and survives within its hosts, and virtually nothing is known about the contribution of critical nutrients such as iron to the bacterium's pathogenesis. It was previously assumed that B. pseudomallei used iron-acquisition systems commonly found in other bacteria, for example siderophores. However, our previous discovery of a clinical isolate carrying a large chromosomal deletion missing the entire malleobactin gene cluster encoding the bacterium's major high-affinity siderophore while still being fully virulent in a murine melioidosis model suggested that other iron-acquisition systems might make contributions to virulence. Here, we deleted the major siderophore malleobactin (mba) and pyochelin (pch) gene clusters in strain 1710b and revealed a residual siderophore activity which was unrelated to other known Burkholderia siderophores such as cepabactin and cepaciachelin, and not due to increased secretion of chelators such as citrate. Deletion of the two hemin uptake loci, hmu and hem, showed that Hmu is required for utilization of hemin and hemoglobin and that Hem cannot complement a Hmu deficiency. Prolonged incubation of a hmu hem mutant in hemoglobin-containing minimal medium yielded variants able to utilize hemoglobin and hemin suggesting alternate pathways for utilization of these two host iron sources. Lactoferrin utilization was dependent on malleobactin, but not pyochelin synthesis and/or uptake. A mba pch hmu hem quadruple mutant could use ferritin as an iron source and upon intranasal infection was lethal in an acute murine melioidosis model. These data suggest that B. pseudomallei may employ a novel ferritin-iron acquisition pathway as a means to sustain in vivo growth.
Author Summary
Burkholderia pseudomallei is the etiologic agent of melioidosis, a multifaceted deadly and difficult to treat disease of equatorial regions of the world. Disease manifestations range from acute infections to long term chronic infections. The factors by which this bacterium causes disease are not yet well understood. Studies thus far focused on elucidation of the roles of traditional virulence factors such as secreted proteins and exopolysaccharides, but virtually nothing is known about the roles of nutrient acquisition systems in B. pseudomallei's survival in its mammalian hosts. One nutrient that is essential for bacterial metabolism and pathogenicity is iron. As free iron is not readily available in nature, bacteria developed numerous mechanisms for iron acquisition from abiotic and biotic sources. These mechanisms include siderophores and hemin/hemoglobin utilization systems, and it is therefore not too surprising that mutants defective in these systems are often impaired in virulence. In this study we show that defined B. pseudomallei mutants defective in siderophore and hemin/hemoglobin utilization systems remain fully lethal in a murine melioidosis model and present evidence for in vitro ferritin-iron acquisition which may be one or perhaps the main means by which this pathogen sustains in vivo growth.
PMCID: PMC3383733  PMID: 22745846
16.  Burkholderia pseudomallei in soil samples from an oceanarium in Hong Kong detected using a sensitive PCR assay 
Melioidosis, caused by Burkholderia pseudomallei, is an emerging infectious disease with an expanding geographical distribution. Although assessment of the environmental load of B. pseudomallei is important for risk assessment in humans or animals in endemic areas, traditional methods of bacterial culture for isolation have low sensitivities and are labor-intensive. Using a specific polymerase chain reaction (PCR) assay targeting a Tat domain protein in comparison with a bacterial culture method, we examined the prevalence of B. pseudomallei in soil samples from an oceanarium in Hong Kong where captive marine mammals and birds have contracted melioidosis. Among 1420 soil samples collected from various sites in the oceanarium over a 15-month period, B. pseudomallei was detected in nine (0.6%) soil samples using bacterial culture, whereas it was detected in 96 (6.8%) soil samples using the specific PCR assay confirmed by sequencing. The PCR-positive samples were detected during various months, with higher detection rates observed during summer months. Positive PCR detection was significantly correlated with ambient temperature (P<0.0001) and relative humidity (P=0.011) but not with daily rainfall (P=0.241) or a recent typhoon (P=0.787). PCR-positive samples were obtained from all sampling locations, with the highest detection rate in the valley. Our results suggest that B. pseudomallei is prevalent and endemic in the oceanarium. The present PCR assay is more sensitive than the bacterial culture method, and it may be used to help better assess the transmission of melioidosis and to design infection control measures for captive animals in this unique and understudied environment.
PMCID: PMC4217092
Burkholderia pseudomallei; culture; melioidosis; oceanarium; PCR; soil
17.  Classification system of foramen magnum meningiomas 
Foramen magnum meningiomas (FMMs) are challenging tumors. We report a classification system based on our experience of 107 tumors.
Materials and Methods:
The three main algorithm criteria included the compartment of development of the tumor, its dural insertion, and its relation to the vertebral artery.
The compartment of development was most of the time intradural (101/107, 94.4%) and less frequently extradural (3/107, 2.8%) or both intra-extradural. (3/107, 2.8%). When developed inside the intradural compartment, FMMs were subdivided into posterior (6/104, 5.8%), lateral (57/104, 54.8%), and anterior (41/104, 39.4%), if their insertion was respectively posterior to the dentate ligament, anterior to the dentate ligament without or with extension over the midline. Anterior and lateral intradural lesions grew below (77/98, 78.6%), above (16/98, 16.3%), or on both sides (5/98, 5.1%) of the VA. Only three cases of extraduralFMMs (3/107, 2.8%) were resected by an antero-lateral approach while all the other ones (104/107, 97.2%) were removed successfully by a postero-lateral approach. Lower cranial nerves were displaced superiorly in FMM growing below the VA but their position cannot be anticipated in other situations.
This classification system helps for defining the best surgical approach but also for anticipating the position of the lower cranial nerves and therefore for reducing the surgical morbidity.
PMCID: PMC2944858  PMID: 20890409
Classification; foramen magnum; meningioma; surgical approach; tumor - vertebral artery
18.  Melioidosis presenting as lymphadenitis: a case report 
BMC Research Notes  2014;7:364.
Melioidosis is an infection caused by the facultative intracellular gram-negative bacterium; Burkholderia pseudomallei. It gives rise to protean clinical manifestations and has a varied prognosis. Although it was rare in Sri Lanka increasing numbers of cases are being reported with high morbidity and mortality. Here we report a case of melioidosis presenting with lymphadenitis which was diagnosed early and treated promptly with a good outcome.
Case presentation
A 53-year-old Sinhalese woman with diabetes presented with fever and left sided painful inguinal lymphadenitis for one month. She had undergone incision and drainage of a thigh abscess three months previously and had been treated with a short course of antibiotics. There was no record that abscess material was tested microbiologically.
She had neutrophil leukocytosis and elevated inflammatory markers. Initial pus culture revealed a scanty growth of “Pseudomonas sp.” and Escherichia coli which were sensitive to ceftazidime and resistant to gentamicin.
Due to the history of diabetes, recurrent abscess formation and the suggestive sensitivity pattern of the bacterial isolates, we actively investigated for melioidosis. The bacterial isolate was subsequently identified as B. pseudomallei by polymerase chain reaction and antibodies to melioidin antigen were found to be raised at a titre of 1:160.
The patient was treated with high dose intravenous ceftazidime for four weeks followed by eradication therapy with cotrimoxazole and doxycycline. As the patient was intolerant to cotrimoxazole, the antibiotics were changed to a combination of co-amoxyclav and doxycycline and continued for 12 weeks. The patient was well after 6 months without any relapse.
Melioidosis is an emerging infection in South Asia. It may present with recurrent abscesses. Therefore it is very important to send pus for culture whenever an abscess is drained. However, it should be noted that the reporting laboratory may be unfamiliar with this bacterium and the isolate may be misidentified as Pseudomonas or even E. coli. Melioidosis should be suspected when an isolate with the typical antibiotic sensitivity pattern of ceftazidime sensitivity and gentamicin resistance is cultured, especially in a patient with diabetes. This will expedite diagnosis and prompt treatment leading to an excellent prognosis.
PMCID: PMC4062509  PMID: 24927768
Melioidosis; Lymphadenitis; Burkholderia pseudomallei; Sri Lanka
19.  The Genetic and Molecular Basis of O-Antigenic Diversity in Burkholderia pseudomallei Lipopolysaccharide 
Lipopolysaccharide (LPS) is one of the most important virulence and antigenic components of Burkholderia pseudomallei, the causative agent of melioidosis. LPS diversity in B. pseudomallei has been described as typical, atypical or rough, based upon banding patterns on SDS-PAGE. Here, we studied the genetic and molecular basis of these phenotypic differences. Bioinformatics was used to determine the diversity of genes known or predicted to be involved in biosynthesis of the O-antigenic moiety of LPS in B. pseudomallei and its near-relative species. Multiplex-PCR assays were developed to target diversity of the O-antigen biosynthesis gene patterns or LPS genotypes in B. pseudomallei populations. We found that the typical LPS genotype (LPS genotype A) was highly prevalent in strains from Thailand and other countries in Southeast Asia, whereas the atypical LPS genotype (LPS genotype B) was most often detected in Australian strains (∼13.8%). In addition, we report a novel LPS ladder pattern, a derivative of the atypical LPS phenotype, associated with an uncommon O-antigen biosynthesis gene cluster that is found in only a small B. pseudomallei sub-population. This new LPS group was designated as genotype B2. We also report natural mutations in the O-antigen biosynthesis genes that potentially cause the rough LPS phenotype. We postulate that the diversity of LPS may correlate with differential immunopathogenicity and virulence among B. pseudomallei strains.
Author Summary
Burkholderia pseudomallei is an environmental Gram-negative bacterium and the cause of melioidosis, an often life-threatening disease affecting people in Southeast Asia and northern Australia. Melioidosis is usually contracted by bacterial inoculation, ingestion or inhalation. Effective vaccines for melioidosis are currently unavailable. This organism contains a large genome, which varies greatly among strains due to a high frequency of genetic recombination. We report here on diversity of lipopolysaccharides (LPS) in this species, a major component of the bacterial outer membrane and a known immunogenic virulence factor. We developed LPS genotyping techniques to study frequency of two major LPS types, known as typical and atypical LPS, in B. pseudomallei strains collected from two endemic regions: Southeast Asia and Northern Australia. LPS genotype variation differed among B. pseudomallei populations. During the investigation, we discovered a new LPS genotype in a sub-population group of B. pseudomallei in Australia. We postulate that such differences are likely to be associated with variable immunopathogenicity and clinical presentation in the human host.
PMCID: PMC3250505  PMID: 22235357
20.  Systematic Review and Consensus Guidelines for Environmental Sampling of Burkholderia pseudomallei 
Burkholderia pseudomallei, a Tier 1 Select Agent and the cause of melioidosis, is a Gram-negative bacillus present in the environment in many tropical countries. Defining the global pattern of B. pseudomallei distribution underpins efforts to prevent infection, and is dependent upon robust environmental sampling methodology. Our objective was to review the literature on the detection of environmental B. pseudomallei, update the risk map for melioidosis, and propose international consensus guidelines for soil sampling.
Methods/Principal Findings
An international working party (Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP)) was formed during the VIth World Melioidosis Congress in 2010. PubMed (January 1912 to December 2011) was searched using the following MeSH terms: pseudomallei or melioidosis. Bibliographies were hand-searched for secondary references. The reported geographical distribution of B. pseudomallei in the environment was mapped and categorized as definite, probable, or possible. The methodology used for detecting environmental B. pseudomallei was extracted and collated. We found that global coverage was patchy, with a lack of studies in many areas where melioidosis is suspected to occur. The sampling strategies and bacterial identification methods used were highly variable, and not all were robust. We developed consensus guidelines with the goals of reducing the probability of false-negative results, and the provision of affordable and ‘low-tech’ methodology that is applicable in both developed and developing countries.
The proposed consensus guidelines provide the basis for the development of an accurate and comprehensive global map of environmental B. pseudomallei.
Author Summary
Melioidosis is a serious infectious disease caused by the Tier 1 selected agent and Gram-negative environmental saprophyte, Burkholderia pseudomallei. The organism is commonly found in soil and water in melioidosis endemic areas. Infection in humans occurs following bacterial inoculation, inhalation or ingestion. There is a striking lack of accurate information on the global risk of melioidosis, something that could be determined from the global distribution of environmental B. pseudomallei. Soil sampling to detect the presence of B. pseudomallei has been ad hoc, poorly standardized, and the available information poorly collated. Negative studies are almost never reported, and there is no published review on this topic. We responded to this problem during the VIth World Melioidosis Congress held in Townsville, Australia in December 2010 by forming the ‘Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP)’. We have since worked together to undertake a systematic review, map the available information, and reach a consensus on low cost methods for the detection of environmental B. pseudomallei. Our goal is to promote the use of these consensus methods and encourage people worldwide to participate in an effort to produce a comprehensive global map of environmental B. pseudomallei.
PMCID: PMC3605150  PMID: 23556010
21.  Host Responses to Melioidosis and Tuberculosis Are Both Dominated by Interferon-Mediated Signaling 
PLoS ONE  2013;8(1):e54961.
Melioidosis (Burkholderia pseudomallei infection) is a common cause of community-acquired sepsis in Northeast Thailand and northern Australia. B. pseudomallei is a soil saprophyte endemic to Southeast Asia and northern Australia. The clinical presentation of melioidosis may mimic tuberculosis (both cause chronic suppurative lesions unresponsive to conventional antibiotics and both commonly affect the lungs). The two diseases have overlapping risk profiles (e.g., diabetes, corticosteroid use), and both B. pseudomallei and Mycobacterium tuberculosis are intracellular pathogens. There are however important differences: the majority of melioidosis cases are acute, not chronic, and present with severe sepsis and a mortality rate that approaches 50% despite appropriate antimicrobial therapy. By contrast, tuberculosis is characteristically a chronic illness with mortality <2% with appropriate antimicrobial chemotherapy. We examined the gene expression profiles of total peripheral leukocytes in two cohorts of patients, one with acute melioidosis (30 patients and 30 controls) and another with tuberculosis (20 patients and 24 controls). Interferon-mediated responses dominate the host response to both infections, and both type 1 and type 2 interferon responses are important. An 86-gene signature previously thought to be specific for tuberculosis is also found in melioidosis. We conclude that the host responses to melioidosis and to tuberculosis are similar: both are dominated by interferon-signalling pathways and this similarity means gene expression signatures from whole blood do not distinguish between these two diseases.
PMCID: PMC3558488  PMID: 23383015
22.  Primary Malignant Lymphoma of the Cranial Vault with Extra- and Intracranial Extension 
Bone involvement is a common finding in many types of lymphomas, particularly in advanced stages. However, cranial vault affliction has been regarded as an exceedingly rare presentation. Here, we report the case of a patient with cranial vault lymphoma who presented with a scalp mass. An 81-year-old woman presented with a gradually growing and non-painful frontal scalp mass that she noticed one month before admission. It was a flatly elevated, round mass measuring about 6×4×4 cm. Computed tomography and magnetic resonance imaging of the brain revealed a contrast-enhancing intracranial extradural mass at the counter-location of the scalp mass. The superior sagittal sinus was involved at the tumor site. Cerebral angiography showed that the tumor feeding vessels originated from the bilateral external carotid arteries. An operation was performed and the tumors were removed together with the involved bone. The pathologic diagnosis was malignant diffuse large B-cell type lymphoma. The patient was transferred to the Hemato-Oncology department for chemotherapy. Primary lymphoma of the cranial vault with scalp mass is very rare but it should be considered in the differential diagnosis of scalp masses. Although the results of reported cases are variable, the combination of surgery, radiation, and chemotherapy appears to offer favorable outcomes.
PMCID: PMC4027115  PMID: 24904887
Primary lymphoma; Cranial vault; Scalp mass
23.  A pain in the neck 
BMJ Case Reports  2011;2011:bcr0920114840.
A 21-year-old man presented to the emergency department with pain and swelling to the right side of his neck and chest wall with associated shortness of breath. Two days earlier, while playing football, he had been involved in a minor collision with another player where he was struck on the right side of his head, but had managed to continue playing. On examination, the patient had extensive cervical surgical emphysema. There were no further positive findings on respiratory and general examination. A chest x-ray demonstrated no rib or clavicular fractures and no pneumothorax. Therefore, a CT was undertaken to ascertain the cause of the surgical emphysema. This demonstrated a pneumomediastinum, pneumopericardium and extradural air in the spinal column in addition to the subcutaneous air. The CT identified no bony trauma and no other injuries. The symptoms resolved spontaneously and follow-up radiography, 9 days later, showed no residual air.
PMCID: PMC3207799  PMID: 22675022
24.  Fulminant holocord intramedullary tubercular abscess with enigmatic presentation 
Intramedullary and subarachnoidal tubercular abscesses are rare forms of spinal tuberculosis as compared with extradural collections secondary to vertebral tuberculosis.
Case Description:
We herein present a 33-year-old, apparently healthy male patient who presented clinically as transverse myelitis, with a lesion at detected at conus cauda, developing fulminant holocord intramedullary tubercular abscess, treated with surgical evacuation and much later with anti-tubercular drugs. Atypical clinical, serological, imaging findings in addition to lack of knowledge of occurrence of fulminant intramedullary tuberculosis led to the delay in starting anti-tubercular treatment.
Early diagnosis requires a high index of suspicion, search for a primary focus of tubercular infection, investigation with magnetic resonance imaging (MRI) of spinal cord, biopsy, and confirmation with microscopy and culture, even in immunocompetent individuals. Early diagnosis, prompt treatment with surgical evacuation of abscess, and anti-tubercular drugs can lead to a good neurological recovery.
PMCID: PMC3622373  PMID: 23607054
Filum terminale; intramedullary; spinal tuberculosis; subarachnoidal; tubercular abscess
25.  Effect of patients' age on management of acute intracranial haematoma: prospective national study 
BMJ : British Medical Journal  2002;325(7371):1001.
To determine whether the management of head injuries differs between patients aged ⩾65 years and those <65.
Prospective observational national study over four years.
25 Scottish hospitals that admit trauma patients.
527 trauma patients with extradural or acute subdural haematomas.
Main outcome measures
Time to cranial computed tomography in the first hospital attended, rates of transfer to neurosurgical care, rates of neurosurgical intervention, length of time to operation, and mortality in inpatients in the three months after admission.
Patients aged ⩾65 years had lower survival rates than patients <65 years. Rates were 15/18 (83%) v 165/167 (99%) for extradural haematoma (P=0.007) and 61/93 (66%) v 229/249 (92%) for acute subdural haematoma (P<0.001). Older patients were less likely to be transferred to specialist neurosurgical care (10 (56%) v 142 (85%) for extradural haematoma (P=0.005) and 56 (60%) v 192 (77%) for subdural haematoma (P=0.004)). There was no significant difference between age groups in the incidence of neurosurgical interventions in patients who were transferred. Logistic regression analysis showed that age had a significant independent effect on transfer and on survival. Older patients had higher rates of coexisting medical conditions than younger patients, but when severity of injury, initial physiological status at presentation, or previous health were controlled for in a log linear analysis, transfer rates were still lower in older patients than in younger patients (P<0.001).
Compared with those aged under 65 years, people aged 65 and over have a worse prognosis after head injury complicated by intracranial haematoma. The decision to transfer such patients to neurosurgical care seems to be biased against older patients.
What is already known on this topicOlder patients with acute intracranial haematomas have significantly higher mortality and poorer functional outcome than younger patients with similar injuriesIntracranial haematomas are larger and more common in older patients with head injury than in younger patientsEarly diagnosis and surgical intervention for operable lesions is a crucial factor in determining patients' outcomesWhat this study addsOlder patients with acute intracranial haematomas were less likely to be transferred for specialist neurosurgical care than younger patients with similar severities of injuries, extracranial injuries, and physiological status at presentationSignificant differences in transfer rates related to age were still seen after pre-existing medical conditions were controlled for
PMCID: PMC131014  PMID: 12411357

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