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1.  The Role of Host and Microbial Factors in the Pathogenesis of Pneumococcal Bacteraemia Arising from a Single Bacterial Cell Bottleneck 
PLoS Pathogens  2014;10(3):e1004026.
The pathogenesis of bacteraemia after challenge with one million pneumococci of three isogenic variants was investigated. Sequential analyses of blood samples indicated that most episodes of bacteraemia were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin of invasive disease. With respect to host determinants, results identified novel properties of splenic macrophages and a role for neutrophils in early clearance of pneumococci. Concerning microbial factors, whole genome sequencing provided genetic evidence for the clonal origin of the bacteraemia and identified SNPs in distinct sub-units of F0/F1 ATPase in the majority of the ex vivo isolates. When compared to parental organisms of the inoculum, ex-vivo pneumococci with mutant alleles of the F0/F1 ATPase had acquired the capacity to grow at low pH at the cost of the capacity to grow at high pH. Although founded by a single cell, the genotypes of pneumococci in septicaemic mice indicate strong selective pressure for fitness, emphasising the within-host complexity of the pathogenesis of invasive disease.
Author Summary
Decades of research on bacterial sepsis have been devoted to analysing the steps that lead from a local event, either carriage or a localised infection, to systemic disease. Our work analyses in depth the events determining systemic infection by one of the main human pathogens, Streptococcus pneumoniae. Consistent with similar findings on the pathogenesis of bacteraemia due to other commensal pathogens, our results show that after an intravenous inoculum of a million pneumococci, the resulting septicaemia is often founded by a single bacterial cell. Investigation into the nature of this monoclonal infection identified strong within-host selective pressure for metabolic fitness during outgrowth of the bacterial population.
doi:10.1371/journal.ppat.1004026
PMCID: PMC3961388  PMID: 24651834
2.  Contribution of different pneumococcal virulence factors to experimental meningitis in mice 
BMC Infectious Diseases  2013;13:444.
Background
Pneumococcal meningitis (PM) is a life-threatening disease with a high case-fatality rate and elevated risk for serious neurological sequelae. In this study, we investigated the contribution of three major virulence factors of Streptococcus pneumoniae, the capsule, pneumococcal surface protein A (PspA) and C (PspC), to the pathogenesis of experimental PM.
Methods
Mice were challenged by the intracranial route with the serotype 4 TIGR4 strain (wt) and three isogenic mutants devoid of PspA, PspC, and the capsule. Survival, bacterial counts, and brain histology were carried out. To study the interaction between S. pneumoniae mutants and microglia, phagocytosis and survival experiments were performed using the BV2 mouse microglial cell line.
Results
Virulence of the PspC mutant was comparable to that of TIGR4. In contrast, survival of animals challenged with the PspA mutant was significantly increased compared with the wt, and the mutant was also impaired at replicating in the brain and blood of infected mice. Brain histology indicated that all strains, except for the unencapsulated mutant, caused PM. Analysis of inflammation and damage in the brain of mice infected with TIGR4 or its unencapsulated mutant demonstrated that the rough strain was unable to induce inflammation and neuronal injury, even at high challenge doses. Results with BV2 cells showed no differences in phagocytic uptake between wt and mutants. In survival assays, however, the PspA mutant showed significantly reduced survival in microglia compared with the wt.
Conclusions
PspA contributed to PM pathogenesis possibly by interacting with microglia at early infection stages, while PspC had limited importance in the disease. The rough mutant did not cause brain inflammation, neuronal damage or mouse death, strengthening the key role of the capsule in PM.
doi:10.1186/1471-2334-13-444
PMCID: PMC3848944  PMID: 24059458
Experimental pneumococcal meningitis; Microglia; PspA; PspC; Capsule
3.  Association between fruits and vegetables intake and frequency of breakfast and snacks consumption: a cross-sectional study 
Nutrition Journal  2013;12:123.
Background
There are very few studies on the frequency of breakfast and snack consumption and its relation to fruit and vegetable intake. This study aims to fill that gap by exploring the relation between irregular breakfast habits and snack consumption and fruit and vegetable intake in Tuscan adolescents. Separate analyses were conducted with an emphasis on the potentially modifying factors of sex and age.
Methods
Data was obtained from the 2010 Tuscan sample of the Health Behaviour in School-aged Children (HBSC) study. The HBSC study is a cross-sectional survey of 11-, 13- and 15-year-old students (n = 3291), selected from a random sample of schools. Multivariate logistic regression was used for analyzing the food-frequency questionnaire.
Results
A significant relation was found between low fruit and vegetable intake and irregular breakfast habits. Similarly, low fruit intake was associated with irregular snack consumption, whereas vegetable intake did not prove to be directly related to irregular snack consumption. Different patterns emerged when gender and age were considered as modifying factors in the analyses. A statistically significant relation emerged only among female students for irregular breakfast habits and fruit and vegetable intake. Generally, older female participants with irregular breakfast habits demonstrated a higher risk of low fruit and vegetable intake. Age pattern varied between genders, and between fruit and vegetable consumption.
Conclusions
Results suggest that for those adolescents who have an irregular consumption of breakfast and snacks, fruit intake occurs with a lower frequency. Lower vegetable consumption was associated with irregular breakfast consumption. Gender and age were shown to be moderators and this indicated the importance of analyzing fruit and vegetable intake and meal types separately.
This study also confirmed that health-promotion campaigns that aim to promote regular meal consumption and consumption of fruits and vegetables need to take into account gender and age differences in designing promotional strategies. Future research should identify evidence-based interventions to facilitate the achievement of the Italian guidelines for a healthy diet for fruit, vegetables and meals intake.
doi:10.1186/1475-2891-12-123
PMCID: PMC3765730  PMID: 23981379
4.  BMI can influence adult males’ and females’ airway hyperresponsiveness differently 
Background
Epidemiological data indicate that obesity is a risk factor for asthma, but scientific literature is still debating the association between changes in body mass index (BMI) and airway hyperresponsiveness (AHR).
Methods
This study aimed at evaluating the influence of BMI on AHR, in outpatients with symptoms suggestive of asthma.
4,217 consecutive adult subjects (2,439 M; mean age: 38.2±14.9 yrs; median FEV1 % predicted: 100 [IQR:91.88-107.97] and FEV1/FVC % predicted: 85.77% [IQR:81.1-90.05]), performed a methacholine challenge test for suspected asthma. Subjects with PD20 < 200 or 200 < PD20 < 800 or PD20 > 800 were considered affected by severe, moderate or mild AHR, respectively.
Results
A total of 2,520 subjects (60% of all cases) had a PD20 < 3,200 μg, with a median PD20 of 366 μg [IQR:168–1010.5]; 759, 997 and 764 patients were affected by mild, moderate and severe AHR, respectively. BMI was not associated with increasing AHR in males. On the contrary, obese females were at risk for AHR only when those with moderate AHR were considered (OR: 1.772 [1.250-2.512], p = 0.001). A significant reduction of FEV1/FVC for unit of BMI increase was found in moderate AHR, both in males (β = −0.255; p =0.023) and in females (β = −0.451; p =0.017).
Conclusions
Our findings indicate that obesity influences AHR only in females with a moderate AHR level. This influence may be mediated by obesity-associated changes in baseline lung function.
doi:10.1186/2049-6958-7-45
PMCID: PMC3529699  PMID: 23157852
Airway hyperresponsiveness; asthma; body mass index; males and females; methacholine test; obesity
5.  Basal and post-ischemic vascular compliance in children/adolescents born small for gestational age 
Background
Intrauterine growth restriction plays a powerful role in influencing later susceptibility to certain chronic diseases, such as hypertension. Endothelial dysfunction and arterial stiffness are early events in the development of cardiovascular diseases (CVDs). We have studied vascular compliance in small for gestational age (SGA) children/adolescents in comparison with that in appropriate for gestational age (AGA) subjects.
Methods
We monitored blood pressure, vascular resistance and compliance in 82 children–adolescents (52 SGA, 30 AGA), by means of pulse wave analysis (CR 2000 HDI) at the radial level, before and after 3 min of ischemic stress at the brachial level.
Results
In the children/adolescents born SGA we found a significant increase in systolic and diastolic blood pressure and vascular resistance in the basal condition; the large and small vessels were stiffer. After ischemia we observed an increased vascular response in the SGA children/adolescents: there was a great diminution of systolic and diastolic blood pressure and a larger increase of the elasticity of the conduit and resistance vessels.
Conclusions
These data show that the SGA group presented some early signs of arterial wall functional disorders. More pediatric data are needed for the evaluation by non-invasive techniques of vascular function in children–adolescents at risk of CVD.
doi:10.1007/s00467-012-2168-y
PMCID: PMC3407354  PMID: 22572870
Hypertension; Small for gestational age; Vascular disease; Arterial stiffness
6.  Seasons can influence the results of the methacholine challenge test 
Annals of Thoracic Medicine  2012;7(2):61-68.
OBJECTIVE:
This study tried to evaluate whether a methacholine test may be influenced by the seasons.
METHODS:
We considered 4826 consecutive subjects with normal spirometry (50.53% males; age: 35.1±16.2; forced expiratory volume in one second: 99.5±13.0%) who underwent a methacholine test for suspected asthma symptoms between 2000 and 2010. They were subdivided into four groups, like the seasons, according to the test dates.
RESULTS:
A total of 1981 (41%) resulted normal (no PD20 was obtained with 2400 μg of methacholine); the others showed a mean LogPD20 of 2.52±0.5 μg. The number of subjects with bronchial hyper-responsiveness (BHR) found in autumn (789, 62.3%) was higher than in summer (583, 56.7%; P=0.03). A higher number of females and overweight/obese subjects showed a BHR in autumn compared with the other seasons. The spring mean LogPD20 value (2.48±0.48 μg) was lower if compared with the one measured in summer (2.59±0.49 μg; P=0.05). LogPD20 value was lower in females and non-smokers in spring compared with summer (P<0.05). Overweight/obese non-smokers showed a lower LogPD20 in spring and autumn compared with that in summer (P<0.05). Autumn was a risk factor (OR: 1.378; P=0.001) for BHR (using a PD20 <2 400 μg as BHR limit), while spring (OR: 1.330; P=0.021) and autumn (OR: 1.331; P=0.020) were risk factors for a more severe BHR (using a PD20 <400 μg as BHR limit).
CONCLUSION:
There was a higher probability of finding BHR in outpatients with suspected asthma in autumn and spring compared with summer. Spring is the season where BHR may be more severe. Females and overweight/obese subjects were those mainly involved in this seasonal variability of BHR.
doi:10.4103/1817-1737.94521
PMCID: PMC3339205  PMID: 22558009
Airway; asthma; bronchial hyper-responsiveness; methacholine challenge test; season
7.  Relationship between 8/9-yr-old school children BMI, parents' BMI and educational level: a cross sectional survey 
Nutrition Journal  2011;10:76.
Background
Parents are responsible not only for the genetic structure of their children, but also for passing onto them their behaviours and attitudes toward life. The aim of this study was to analyse the connection between school-age children's obesity and that of their parents as well as between child obesity and parents' educational level, as a proxy indicator of the socio-economic status (SES) of families in Tuscany.
Methods
The children sample was selected from "OKkio alla Salute 2010" (a cross sectional survey carried out by the Italian Institute of Health) and consisted of 1,751 (922 males and 855 females) 8-9 year-old school children. Weight and height were measured by ad hoc trained personnel, and Body Mass Index (BMI) categories were calculated using Cole et al.'s cut-off. Parents' weight, height and educational level were collected by a self-administered questionnaire. The educational levels were classified as high, medium and low.
Results
The prevalence of obese children increased along the parents' BMI category: from 1.4% for underweight mothers to 30.3% for obese mothers and from 4% for under-normal-weight fathers to 23.9% for obese fathers (p < 0.001). An inverse relationship was observed between the parents' educational level and child obesity, the lowest educational level corresponding to the highest prevalence of obese children: 9.3% for mothers with a low educational level compared to 5.8% for mothers with a high educational level (p = 0.15); similarly, the corresponding prevalence for fathers was 9.5% compared to 4.5% (p = 0.03).
Conclusion
Parents' obesity and the cultural resources of the family, particularly the father's, seem to influence the prevalence of overweight and obesity in Tuscan children.
doi:10.1186/1475-2891-10-76
PMCID: PMC3160354  PMID: 21771312
childhood; obesity; underweight; parents' nutritional status; educational level
8.  The presence of bacteria species in semen and sperm quality 
Purpose
To verify the prevalence of semen bacterial contamination and whether the contamination could decrease sperm quality.
Methods
Spermiogram, semen culture, and sperm transmission electron microscopy (TEM) analysis were performed. TEM data were elaborated using a mathematical formula that calculates a fertility index (FI)—able to define patients as fertile or infertile—and the percentage of sperm apoptosis, immaturity and necrosis. We aligned the amino acid sequence of beta-tubulin with protein of the most frequent species isolated from semen.
Results
Patients were divided according to the contaminating species; in each group, we observed fertile individuals, in whom the semen quality was similar to that of controls and infertile men whose sperm quality was significantly decreased, in terms of motility, FI, apoptosis and necrosis. Partial homology between β-tubulin and bacterial proteins was observed.
Conclusion
Sperm bacterial contamination is quite frequent and could contribute to the deterioration of the sperm quality of infertile men.
doi:10.1007/s10815-008-9283-5
PMCID: PMC2649329  PMID: 19089609
Bacteria; Semen quality; Spermatozoa; TEM

Results 1-8 (8)