Georges Mascart

Incidence and virulence determinants of verocytotoxin-producing Escherichia coli infections in the Brussels-Capital Region, Belgium, in 2008-2010.

ABSTRACT The incidence of verocytotoxin-producing Escherichia coli (VTEC) was investigated by PCR in all human stools from Universitair Ziekenhuis Brussel (UZB) and in selected stools from six other hospital laboratories in the Brussels-Capital Region, Belgium, collected between April 2008 and October 2010. The stools selected to be included in this study were those from patients with hemolytic-uremic syndrome (HUS), patients with a history of bloody diarrhea, patients linked to clusters of diarrhea, children up to the age of 6 years, and stools containing macroscopic blood. Verocytotoxin genes (vtx) were detected significantly more frequently in stools from patients with the selected conditions (2.04%) than in unselected stools from UZB (1.20%) (P = 0.001). VTEC was detected most frequently in patients with HUS (35.3%), a history of bloody diarrhea (5.15%), or stools containing macroscopic blood (1.85%). Stools from patients up to the age of 17 years were significantly more frequently vtx positive than those from adult patients between the ages of 18 and 65 years (P = 0.022). Although stools from patients older than 65 years were also more frequently positive for vtx than those from patients between 18 and 65 years, this trend was not significant. VTEC was isolated from 140 (67.9%) vtx-positive stools. One sample yielded two different serotypes; thus, 141 isolates could be characterized. Sixty different O:H serotypes harboring 85 different virulence profiles were identified. Serotypes O157:H7/H− (n = 34), O26:H11/H− (n = 21), O63:H6 (n = 8), O111:H8/H− (n = 7), and O146:H21/H− (n = 6) accounted for 53.9% of isolates. All O157 isolates carried vtx2, eae, and a complete O island 122 (COI-122); 15 also carried vtx1. Non-O157 isolates (n = 107), however, accounted for the bulk (75.9%) of isolates. Fifty-nine (55.1%) isolates were positive for vtx1, 36 (33.6%) were positive for vtx2, and 12 (11.2%) carried both vtx1 and vtx2. Pulsed-field gel electrophoresis revealed wide genetic diversity; however, small clusters of O157, O26, and O63:H6 VTEC that could have been part of unidentified outbreaks were identified. Antimicrobial resistance was observed in 63 (44.7%) isolates, and 34 (24.1%) showed multidrug resistance. Our data show that VTEC infections were not limited to patients with HUS or bloody diarrhea. Clinical laboratories should, therefore, screen all stools for O157 and non-O157 VTEC using selective media and a method for detecting verocytotoxins or vtx genes.

Mathematical model for the control of nosocomial norovirus.

A gastroenteritis outbreak in a long-term care facility was analysed by means of a SEIR (Susceptible, Exposed/Latent phase, Infected/Infectious, and Recovered) compartment model of infection dynamics in a closed population [96 beds; attack rate=41%; R0 (basic reproductive number)=3.74; generation time approximately 1 day; duration of disease approximately 2 days; theoretical infinite (1000 days) duration of hospital stay]. The patient-turnover variation was simulated to determine the effect of the length of hospital stay on the endemic level of gastroenteritis perpetuating the epidemic phase in an open population. With all the other parameters held constant, the prevalence of infected patients in the endemic phase (50 days after the beginning of the outbreak) increased markedly from five to 18 cases as the hospital stay increased from one-tenth of a day (one-day care) to one or two days; the prevalence decreased exponentially with the length of hospital stay, being fewer than five cases for hospital stays >50 days. In conclusion, the endemic prevalence of norovirus gastroenteritis is critically dependent on the patient turnover within hospital wards. For the usual range of hospital stay (0.1-20 days), the prevalence level is sufficiently elevated to maintain the perpetuation of gastroenteritis within the population of institutionalised patients. In long-term care facilities (hospital stay >20 days), the patient turnover is sufficiently low for one to expect a spontaneous extinction of epidemic outbreak without endemic perpetuation. When an epidemic outbreak occurs in an acute-care setting, reinforcement of infection control measures, including closure of the ward, is required to break the transmission chain.

Management of an Outbreak of Clostridium difficile–Associated Disease Among Geriatric Patients

OBJECTIVE To describe a nosocomial outbreak of Clostridium difficile-associated disease (CDAD). DESIGN A traditional outbreak investigation. SETTING Geriatric department of a tertiary care teaching hospital from March through April 2003. METHODS The outbreak was detected by the C. difficile surveillance program of the infection control unit. CDAD was diagnosed by stool culture and fecal toxin A detection with a qualitative rapid immunoassay. Isolates of C. difficile were serotyped and genotyped using pulsed-field gel electrophoresis. RESULTS The incidence of CDAD increased from 27 cases per 100,000 patient-days in the 6-month period before the outbreak to 99 cases per 100,000 patient-days during the outbreak. This outbreak involved 21 of 92 patients in 4 geriatric wards, which were located at 2 geographically distinct sites and staffed by the same medical team. The mean age of patients was 83 years (range, 71-100 years). Five (24%) of the 21 patients had community-acquired diarrhea, and secondary hospital transmission resulted in 3 clusters involving 16 patients. Serotyping and genotyping were performed on isolates in stool specimens from 19 different patients; 16 of these isolates were serotype A1, whereas 3 displayed profiles different from the outbreak strain. Management of this outbreak consisted in reinforcement of contact isolation precautions for patients with diarrhea, cohorting of infected patients in the same ward, and promotion of hand hygiene. Relapses occurred in 6 (29%) of 21 patients. CONCLUSION Control of this rapidly developing outbreak of CDAD was obtained with early implementation of cohorting and ward closure and reinforcement of environmental disinfection, hand hygiene, and enteric isolation precautions.

Variations in catheter-related bloodstream infections rates based on local practices

BackgroundCatheter-related bloodstream infection (CRBSI) surveillance serves as a quality improvement measure that is often used to assess performance. We reviewed the total number of microbiological samples collected in three Belgian intensive care units (ICU) in 2009–2010, and we described variations in CRBSI rates based on two factors: microbiological documentation rate and CRBSI definition which includes clinical criterion for coagulase-negative Staphylococcus (CNS) episode.FindingsCRBSI rates were 2.95, 1.13 and 1.26 per 1,000 estimated catheter-days in ICUs A, B and C, respectively. ICU B cultured fewer microbiological samples and reported the lowest CRBSI rate. ICU C had the highest documentation rate but was assisted by support available from the laboratory for processing single CNS positive blood cultures. With the exclusion of clinical criterion, CRBSI rates would be reduced by 19%, 45% and 0% in ICUs A, B and C, respectively.ConclusionCRBSI rates may be biased by differences of blood culture sampling and CRBSI definition. These observations suggest that comparisons of CRBSI rates in different ICUs remain difficult to interpret without knowledge of local practices.

Botulisme infantile après exposition à du miel

Infant botulism is a rare neuroparalytic disease caused by the neurotoxin of Clostridium botulinum. Initial clinical features are constipation, poor feeding, descending hypotonia, drooling, irritability, weak crying and cranial nerve dysfunctions. We describe the clinical progression and the epidemiological investigation carried out in a 3-month-old infant. Better knowledge of the disease should allow faster diagnosis and adequate management. We emphasize the risks associated with honey exposure in children less than one year old and that honey should not be fed to infants under 12 months of age.

Group A Streptococcus Colonies from a Single Throat Swab Can Have Heterogeneous Antimicrobial Susceptibility Patterns.

This study describes for the first time heterogeneity of antibiotic resistance profiles among group A Streptococcus isolates originating from a single throat swab in patients with acute pharyngitis. For each throat swab, 10 group A Streptococcus colonies were randomly selected from the primary plate and subcultured to a secondary plate. These isolates were characterized by various phenotypic and genotypic methods. Our results demonstrated that differing antibiotic resistance profiles were present in 19% of pediatric patients with acute pharyngitis before antimicrobial treatment. This heterogeneity likely resulted from horizontal gene transfer among streptococcal isolates sharing the same genetic background. As only a minority of colonies displayed antibiotic resistance among these heterogeneous samples, a classical diagnostic antibiogram would have classified them in most instances as “susceptible,” although therapeutic failure could be caused by the proliferation of resistant strains after initiation of antibiotic treatment.

Enteritis and septicaemia due to Campylobacter jejuni.

SummaryWe present the case of a female patient of 69 years of age who had a septicaemia clue to Campylobacter jejuni with non-specific symptomatology following an episode of diarrhoea due to the organism. After describing the technique of isolation we consider the different forms of human infection due to Campylobacter spp; those due to C. fetus intestinalis principally occuring in patients with an underlying pathology, and those due to C. jejuni occuring in healthy individuals.Generalised Campylobacter spp. infection due to C. jejuni is in reality a fairly rare complication of C. jejuni enteritis wich is of much more frequent occurence particularly in infants.

Accuracy of automated flow cytometry-based leukocyte counts to rule out urinary tract infection in febrile children: A prospective cross-sectional study

ABSTRACT Automated flow cytometry of urine remains an incompletely validated method to rule out urinary tract infection (UTI) in children. This cross-sectional analytical study was performed to compare the predictive values of flow cytometry and a dipstick test as initial diagnostic tests for UTI in febrile children and prospectively included 1,106 children (1,247 episodes). Urine culture was used as the gold standard test for diagnosing UTI. The performance of screening tests to diagnose UTI were established using receiver operating characteristic (ROC) analysis. Among these 1,247 febrile episodes, 221 UTIs were diagnosed (17.7% [95% confidence interval {CI}, 15.6 to 19.8%]). The area under the ROC curve for flow cytometry white blood cell (WBC) counts (0.99 [95% CI, 0.98 to 0.99]) was significantly superior to that for red blood cell (0.74 [95% CI, 0.70 to 0.78]) and bacterial counts (0.89 [95% CI, 0.87 to 0.92]) (P < 0.001). Urinary WBC counts also had a significantly higher area under the ROC curve than that of the leukocyte esterase (LE) dipstick (0.92 [95% CI, 0.90 to 0.94]), nitrite dipstick (0.83 [95% CI, 0.80 to 0.87]), or the combination of positive LE and/or nitrite dipstick (0.91 [95% CI, 0.89 to 0.93]) test (P < 0.001). The presence of ≥35 WBC/μl of urine was the best cutoff point, yielding both a high sensitivity (99.5% [95% CI, 99 to 100%]) and an acceptable specificity (80.6% [95% CI, 78 to 83%]). Using this cutoff point would have reduced the number of samples sent to the laboratory for culture by 67%. In conclusion, the determination of urinary WBC counts by flow cytometry provides optimal performance as an initial diagnostic test for UTI in febrile children.