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1.  Increased EMRSA-15 health-care worker colonization demonstrated in retrospective review of EMRSA hospital outbreaks 
Health care worker (HCW) colonization with methicillin resistant Staphylococcus aureus (MRSA) is a documented cause of hospital outbreaks and contributes to ongoing transmission. At Royal Perth Hospital (RPH) it had been anecdotally noted that the increasing prevalence of EMRSA-15 appeared to be associated with increased HCW colonization compared with Aus2/3-EMRSA. Hence we compared HCW colonization rates during outbreaks of EMRSA-15 and Aus2/3-EMRSA at a single institution.
We performed a retrospective review of EMRSA-15 and Aus2/3-EMRSA outbreaks from 2000–2009 at RPH, a quaternary hospital in Western Australia. Outbreak files were reviewed and relevant data extracted.
Ten EMRSA-15 outbreaks were compared with seven Aus2/3 outbreaks. The number of patients colonized was similar between EMRSA-15 and Aus2/3-EMRSA outbreaks (median 7 [range 3–20] and 11 [5–26], respectively; P = 0.07) but the number of HCWs colonized was significantly higher in EMRSA-15 outbreaks compared to Aus2/3-EMRSA outbreaks (median 4 [range 0–15] and 2 [1-3], respectively; P = 0.013). The percentage of HCWs colonized was also higher in EMRSA-15 outbreaks versus Aus2/3-EMRSA outbreaks (median 3.4% [range 0–5.5%] and 0.81% [0.56–2.2%], respectively; P = 0.013).
This study demonstrates a higher level of HCW colonization during EMRSA-15 outbreaks compared with Aus2/3-EMRSA outbreaks. This finding suggests that MRSA vary in their ability to colonize HCWs and contribute to outbreaks. MRSA type should be determined during outbreaks and future research should investigate the mechanisms by which EMRSA-15 contributes to increased HCW colonization.
PMCID: PMC3944736  PMID: 24588849
Methicillin resistant Staphylococcus aureus; Outbreak; Health care workers; EMRSA-15; Aus2/3-EMRSA
2.  Antimicrobial stewardship in long term care facilities: what is effective? 
Intense antimicrobial use in long term care facilities promotes the emergence and persistence of antimicrobial resistant organisms and leads to adverse effects such as C. difficile colitis. Guidelines recommend development of antimicrobial stewardship programs for these facilities to promote optimal antimicrobial use. However, the effectiveness of these programs or the contribution of any specific program component is not known. For this review, publications describing evaluation of antimicrobial stewardship programs for long term care facilities were identified through a systematic literature search. Interventions included education, guidelines development, feedback to practitioners, and infectious disease consultation. The studies reviewed varied in types of facilities, interventions used, implementation, and evaluation. Comprehensive programs addressing all infections were reported to have improved antimicrobial use for at least some outcomes. Targeted programs for treatment of pneumonia were minimally effective, and only for indicators of uncertain relevance for stewardship. Programs focusing on specific aspects of treatment of urinary infection – limiting treatment of asymptomatic bacteriuria or prophylaxis of urinary infection – were reported to be effective. There were no reports of cost-effectiveness, and the sustainability of most of the programs is unclear. There is a need for further evaluation to characterize effective antimicrobial stewardship for long term care facilities.
PMCID: PMC3931475  PMID: 24521205
Long term care facility; Antimicrobial stewardship; Pneumonia; Urinary tract infection
3.  Predictors of hospital surface contamination with Extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae: patient and organism factors 
The role of the hospital environment in transmission of ESBL-Klebsiella pneumoniae (ESBL-KP) and ESBL-Escherichia coli (ESBL-EC) is poorly defined. Recent data however suggest that in the hospital setting, ESBL-KP is more transmissible than ESBL-EC. We sought therefore to measure the difference in hospital contamination rates between the two species and to identify key risk factors for contamination of the hospital environment with these organisms.
We systematically sampled 8 surfaces in the rooms and bathrooms of adult patients colonized or infected with ESBL-EC or ESBL-KP throughout their hospital stay. Data were collected on factors potentially affecting contamination rates. Environmental contamination was defined as recovery of an ESBL-producing organism matching the source patient’s isolate. Multivariate logistic regression analysis was performed at the level of the patient visit using generalized estimating equations to identify independent predictors of environmental contamination.
24 patients (11 with ESBL-KP, 11 ESBL-EC and 2 with both organisms) had 1104 swabs collected during 138 visits. The overall contamination rate was 3.4% (38/1104) and was significantly higher for ESBL-KP than ESBL-EC (5.4% versus 0.4%; p < 0.0001). After multivariate analysis, environmental contamination was found to be negatively associated with carbapenem exposure (OR 0.06 [95% CI 0.01-0.61]; p = 0.017) and positively associated with the presence of an indwelling urinary catheter (OR 6.12 [95% CI 1.23-30.37]; p = 0.027) and ESBL-KP in the source patient (OR 26.23 [95% CI 2.70-254.67]; p = 0.005).
Contamination of the hospital environment with ESBL-producing Enterobacteriaceae (ESBL-E) is inversely associated with carbapenem exposure. Predictors of hospital contamination with ESBL-E include: indwelling urinary catheters and ESBL-KP. Rooms of patients with ESBL-KP have substantially higher contamination rates than those with ESBL-EC. This finding may help explain the apparently higher transmissibility of ESBL-KP in the hospital setting.
PMCID: PMC3922547  PMID: 24491119
4.  Reviewer acknowledgement 2013 
Contributing reviewers
Antimicrobial Resistance and Infection Control would like to thank the following colleagues for their assistance with peer review of manuscripts for the journal in 2013.
PMCID: PMC3896811  PMID: 24433391
5.  Adjustment of the MRSA Search and Destroy policy for outpatients in the Netherlands: a prospective cohort study with repeated prevalence measurements 
In the Netherlands a successful MRSA Search and Destroy policy is applied in healthcare institutes. We determined the effect of an adjustment in the MRSA Search and Destroy policy for patients in the outpatient clinic on the MRSA transmission to health care workers (HCW).
In June 2008 an adjustment in the policy for outpatients was introduced in a large teaching hospital. Following this adjustment MRSA positive patients and patients at risk could be seen and treated applying general precautions, without additional protective measures. Also, disinfection of the room after the patient had left was abandoned. To monitor the effect of this policy on the transmission of MRSA all physicians and health care workers of the outpatient clinic were screened for MRSA carriage repeatedly.
Before the introduction of the adjusted policy all physicians and HCW of the outpatient clinic were screened (=0-measurement, n = 1,073). None of them was found to be MRSA positive. After introduction of the policy in June 2008 the screening was repeated in October 2008 (n = 1,170) and April 2009 (n = 1,128). In April 2009 one health care worker was MRSA positive resulting in a mean prevalence of 0.09%. This is lower than the known prevalence in HCW. The health care worker was colonized with the livestock-related Spa type t011. As far as we could verify, no patients with this Spa-type had been cared for by the health care worker.
The adjusted MRSA policy did not lead to detectable transmission of MRSA to HCW and was associated with less disturbances in the work flow.
PMCID: PMC3896826  PMID: 24428940
MRSA; Outpatient clinic; Outpatients; Staphylococcus aureus; Search & Destroy policy; Transmission
6.  Trends in antiviral therapy of adults hospitalized with influenza in Canada since the end of the 2009 pandemic 
Multiple observational studies have associated antiviral treatment of patients hospitalized with influenza with improved outcome, including reduced mortality. During the 2009–2010 H1N1 pandemic increased use of antiviral treatment of hospital patients was reported. We have carried out prospective surveillance for influenza in patients in a large network of Canadian hospitals since 2006. We wished to assess trends in antiviral use in the two seasons (2010–2011 and 2011–2012) since the end of the pandemic.
Adults (>16 years) testing positive for influenza at the time of or during admission to participating Canadian hospitals were prospectively reviewed. In 2009–2010 there were 1132 confirmed cases, 1107 in 2010–2011 and 631 in 2011–2012. Information on antiviral therapy was available in >95% in each year. Rising to 89.6% in 2009, the proportion of adult patients treated with antiviral therapy fell to 79.9% and 65.7% in the two subsequent seasons (p < 0.001). Oseltamivir was the antiviral agent used in >98% of cases in each year. The median time from onset of symptoms to initiation of antiviral therapy was three days. The treatment proportion fell across all age groups, co-morbid conditions and disease severity.
Despite evidence for benefit of antiviral therapy, and clinical practice guidelines recommending treatment of this population, antiviral therapy of Canadian adults hospitalized with influenza has progressively fallen in the two seasons since the end of the 2009–2010 influenza pandemic.
PMCID: PMC3895698  PMID: 24405855
7.  Persistence of related bla-IMP-4 metallo-beta-lactamase producing Enterobacteriaceae from clinical and environmental specimens within a burns unit in Australia - a six-year retrospective study 
To describe the clinical epidemiology, environmental surveillance and infection control interventions undertaken in a six-year persistence of bla-IMP-4 metallo-beta-lactamase (MBL) producing Enterobacteriaceae within a separately confined hospital burns unit in a tertiary hospital in Sydney, Australia.
MBL positive clinical and environmental isolates were collected from the Burns Unit, from the first detection of isolates in September 2006 to August 2012. Unit-acquired clinical isolates were included, and patient outcomes analyzed amongst those who acquired clinically significant infections. Environmental isolates were analyzed with regard to relationship to clinical isolates, bacterial species, and persistence despite cleaning efforts.
Thirty clinical isolates detected from 23 patients were identified. Clinically significant infection developed in 7 (30%) patients – 2 bacteremias, 2 central venous catheter tip infections without bacteremia, and 3 wound infections. All patients survived at 30 days. Seventy-one environmental isolates were confirmed to be MBL-positive, with 85% sourced from shower facilities or equipment. MBL organisms persisted at these sites despite both usual hospital cleaning, and following targeted environmental disinfection interventions.
Clear association exists between environmental Burns Unit contamination by MBLs and subsequent patient colonization. Clinical infection occurred in a small proportion of patients colonized by MBLs, and with generally favorable outcomes. Its persistence in the Burns Unit environment, despite concerted infection control measures, pose concern for ongoing clinical transmission.
PMCID: PMC3878348  PMID: 24345195
Carbapenem-resistant Enterobacteriaceae; bla-IMP-4 metallo-beta-lactamase enzyme; Hospital-acquired infection; Infection control; Environmental surveillance
9.  Optimizing antimicrobial prescribing: Are clinicians following national trends in methicillin-resistant staphylococcus aureus (MRSA) infections rather than local data when treating MRSA wound infections 
Clinicians often prescribe antimicrobials for outpatient wound infections before culture results are known. Local or national MRSA rates may be considered when prescribing antimicrobials. If clinicians prescribe in response to national rather than local MRSA trends, prescribing may be improved by making local data accessible. We aimed to assess the correlation between outpatient trends in antimicrobial prescribing and the prevalence of MRSA wound infections across local and national levels.
Monthly MRSA positive wound culture counts were obtained from The Surveillance Network, a database of antimicrobial susceptibilities from clinical laboratories across 278 zip codes from 1999–2007. Monthly outpatient retail sales of linezolid, clindamycin, trimethoprim-sulfamethoxazole and cephalexin from 1999–2007 were obtained from the IMS Health XponentTM database. Rates were created using census populations. The proportion of variance in prescribing that could be explained by MRSA rates was assessed by the coefficient of determination (R2), using population weighted linear regression.
107,215 MRSA positive wound cultures and 106,641,604 antimicrobial prescriptions were assessed. The R2 was low when zip code-level antimicrobial prescription rates were compared to MRSA rates at all levels. State-level prescriptions of clindamycin and linezolid were not correlated with state MRSA rates. The variance in state-level prescribing of clindamycin and linezolid was correlated with national MRSA rates (clindamycin R2 = 0.17, linezolid R2 = 0.22).
Clinicians may rely on national, not local MRSA data when prescribing clindamycin and linezolid for wound infections. Providing local resistance data to prescribing clinicians may improve antimicrobial prescribing and would be a possible target for future interventions.
PMCID: PMC3853220  PMID: 24128420
Drug utilization; Antimicrobial prescribing; Methicillin-resistant Staphylococcus aureus
10.  In-vitro experimental evaluation of skin-to-surface recovery of four bacterial species by antibacterial and non-antibacterial medical examination gloves 
The number of bacteria recovered from a stainless steel coupon after touching a pigskin substrate with an examination glove coated on its outside with polyhexanide (PHMB), as compared to the number of bacteria recovered in the same manner with non-coated control gloves was evaluated.
Suspensions containing 1 × 109 colony-forming units of 4 clinically relevant bacterial species (Enterococcus faecium ATCC #51559; Escherichia coli ATCC #25922; Klebsiella pneumoniae ATCC #4352; and Staphylococcus aureus ATCC #33591) were used to contaminate Gamma-irradiated pigskin substrates. Bacterial recoveries from the pigskin substrate, stainless steel coupons, and each glove swatch were performed. A difference in the bacterial recovery from the stainless steel coupons after touching with coated and uncoated control gloves was measured.
For E. faecium, the coated glove showed a reduction of 4.63 log10 cfu recovery, when compared to control gloves. For E. coli, the coated glove showed 5.48 log10 cfu, for K. pneumoniae 5.03 log10 cfu, and for S. aureus 5.72 log10 cfu recovery, when compared to the non-coated control glove.
An in-vitro experiment designed to mimic cross-contamination of clinically relevant bacteria in a simulated healthcare setting following glove contact with a contaminated biological surface and cross-transfer to a stainless steel surface has demonstrated that an examination glove coated on its outside surface with PHMB was able to reduce bacterial recovery from a contaminated surface by > 4 log10 cfu, compared to a control non-coated examination glove. These elaborated results may encourage further clinical investigation on the clinical impact of an antibacterial examination glove.
PMCID: PMC3852982  PMID: 24119412
Examination glove; Surface contamination; Antimicrobial glove; Polyhexanide; PHMB; Cross-contamination
11.  Nasal carriage rate of methicillin resistant Staphylococcus aureus among Dessie Referral Hospital Health Care Workers; Dessie, Northeast Ethiopia 
Staphylococcus aureus is a common cause of community and hospital acquired infections. One of the important sources of staphylococci for nosocomial infection is nasal carriage among hospital personnel. Emergence of drug resistant strains especially methicillin resistant Staphylococcus aureus is a serious problem in hospital environments. The aim of this study was to determine the nasal carriage rate of methicillin resistant Staphylococcus aureus among Dessie Referral Hospital healthcare-workers in Ethiopia.
A cross sectional study was conducted on a total of 118 healthcare workers. Nasal swabs were collected and cultured on Mannitol Salt Agar. Slide coagulase test was performed. An oxacillin susceptibility test was carried out on Muller Hinton agar using modified Kirby-Bauer disc diffusion method.
Of the 118 healthcare workers, 34 (28.8%) carried S. aureus of which 15 were methicillin resistant. Therefore, 12.7% of all HCWs were identified as MRSA carriers. The rate of methicillin resistance among all S. aureus isolates was 44.1% (15/34). MRSA carriage was particularly high among nurses (21.2%). The highest rate of MRSA carriers (57.1%) were workers of surgical wards.
The high rate of nasal MRSA carriage among healthcare workers found in this study indicates the need for adjusted infection control measures to prevent MRSA transmission in our healthcare setting.
PMCID: PMC3851550  PMID: 24088259
MRSA; Healthcare workers; Nasal carriage; S. aureus
12.  Effectiveness of visual inspection compared with non-microbiologic methods to determine the thoroughness of post-discharge cleaning 
Published data to date have provided a limited comparison between non-microbiologic methods—particularly visual inspection—and a microbiologic comparator to evaluate the effectiveness of environmental cleaning of patient rooms. We sought to compare the accuracy of visual inspection with other non-microbiologic methods of assessing the effectiveness of post-discharge cleaning (PDC).
Prospective evaluation to determine the effectiveness of PDC in comparison to a microbiologic comparator. Using a highly standardized methodology examining 15 high-touch surfaces, the effectiveness of PDC was evaluated by visual inspection, the removal of fluorescent marker (FM) placed prior to room occupancy, quantification of adenosine triphosphate (ATP) levels, and culture for aerobic colony counts (ACC).
Twenty rooms including 293 surfaces were sampled in the study, including 290 surfaces sampled by all four methods. ACC demonstrated 72% of surfaces to be microbiologically clean. Visual inspection, FM, ATP demonstrated 57%, 49%, and 66% of surfaces to be clean. Using ACC as a microbiologic comparator, the sensitivity of visual inspection, FM, and ATP to detect a clean surface were 60%, 51%, and 70%, respectively; the specificity of visual inspection, FM, and ATP were 52%, 56%, and 44%.
In assessing the effectiveness of PDC, there was poor correlation between the two most frequently studied commercial methods and a microbiologic comparator. Visual inspection performed at least as well as commercial methods, directly addresses patient perception of cleanliness, and is economical to implement.
PMCID: PMC3852477  PMID: 24088298
Environmental cleaning; Surface contamination; Nosocomial transmission
13.  Algorithm for pre-emptive glycopeptide treatment in patients with haematologic malignancies and an Enterococcus faecium bloodstream infection 
Nowadays Enterococcus faecium has become one of the most emerging and challenging nosocomial pathogens. The aim of this study was to determine risk factors in haematology patients who are at risk of an Enterococcus faecium bloodstream infection (BSI) and should be considered for pre-emptive glycopeptide treatment. With these identified risk factors a prediction model can be developed for clinical use.
Retrospectively clinical and microbiological data in 33 patients with an E. faecium BSI were compared to 66 control patients during a 5-year period at the haematology ward. Multivariate logistic regression was used to explore the independent risk factors and a prediction model was developed to determine the risk of an E. faecium BSI.
E. faecium BSIs were found to be associated with high mortality rates. Independent risk factors for E. faecium BSI were colonization with E. faecium 30 days prior to blood culture (OR 5.71; CI 1.7-18.7), combination of neutropenia and abdominal focus (4.37; 1.4-13.4), age > 58 years (4.01; 1.3-12.5), hospital stay prior to blood culture > 14 days (3.55; 0.98-12.9) and CRP (C-reactive protein) level >125 mg/L (4.37; 1.1-10.2).
Using data from this study, risk stratification for the development of an E. faecium BSI in patients with haematological malignancies is possible. Pre-emptive treatment should be considered in those patients who are at high risk. Using a prediction model as designed in this study, antibiotic stewardship in terms of prudent use of glycopeptides can be improved and might be helpful in controlling further spread of VRE (vancomycin resistant enterococci).
PMCID: PMC3856451  PMID: 24025668
Enterococcus faecium; Haematologic patients; Risk factors; Glycopeptides; Antibiotic stewardship
14.  No evidence so far for the dissemination of carbapenemase-producing Enterobactericeae in the community in Switzerland 
Carbapenemase-producing Enterobacteriaceae represent an increasing threat to public health and to the treatment of serious nosocomial infections. The aim of this study was to screen for the presence of carbapenemase-producing Enterobacteriaceae in human carriers in community settings in Switzerland, a country representative of central Europe.
Three hundred and fourteen stool samples of healthy staff members of a meat-processing company and 291 fecal swabs from primary care patients were recovered in Switzerland between April 2012 and July 2012 and were tested for carbapenemase-producing Enterobacteriaceae isolates by selecting for growth on a carbapenem-containing selective medium. Six resulting isolates (5 Escherichia coli and 1 Citrobacter youngae) were subjected to antimicrobial susceptibility tests and PCR analysis by screening for the carbapenemase genes blaOXA-48, blaVIM, blaNDM-1, and blaKPC as well as for the extended-spectrum ß-lactamase genes blaTEM,blaSHV, blaCTX-M and blaCMY-2. No carbapenemase genes were detected. Resistance to ß-lactam antibiotics was due to carriage of the extended-spectrum ß-lactamase CTX-M-15 in 4 isolates, to CTX-M-14 in one further isolate and to the plasmidic AmpC-ß-lactamase CMY-2 in one isolate.
These results show that carbapenemase-producing Enterobacteriaceae are as yet not present in the community. Continuous surveillance is necessary to anticipate future trends in the prevalence and dissemination of carbapenem resistant isolates in the population.
PMCID: PMC3766247  PMID: 24139304
Carbapenemase; Dissemination; Enterobacteriaceae; Healthy carriers
15.  Money and transmission of bacteria 
Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, the Leu was the only banknote to yield VRE after one day of drying. Other currencies either enabled the survival of Extended-Spectrum Beta-Lactamases (ESBL) and VRE (e.g. Euro), but not of MRSA, or the other way round (e.g. US Dollar). While a variety of factors such as community hygiene levels, people’s behaviour, and antimicrobial resistance rates at community level obviously have influence on the transmission of resistant microorganisms, the type of banknote-paper may be an additional variable to consider.
PMCID: PMC3765964  PMID: 23985137
16.  Epidemiology of Clostridium difficile infection in Asia 
While Clostridium difficile infection (CDI) has come to prominence as major epidemics have occurred in North America and Europe over the recent decade, awareness and surveillance of CDI in Asia have remained poor. Limited studies performed throughout Asia indicate that CDI is also a significant nosocomial pathogen in this region, but the true prevalence of CDI remains unknown. A lack of regulated antibiotic use in many Asian countries suggests that the prevalence of CDI may be comparatively high. Molecular studies indicate that ribotypes 027 and 078, which have caused significant outbreaks in other regions of the world, are rare in Asia. However, variant toxin A-negative/toxin B-positive strains of ribotype 017 have caused epidemics across several Asian countries. Ribotype smz/018 has caused widespread disease across Japan over the last decade and more recently emerged in Korea. This review summarises current knowledge on CDI in Asian countries.
PMCID: PMC3718645  PMID: 23816346
Clostridium Difficile; Clostridium Infections In Humans; Epidemiology

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