Houssein Gbaguidi-Haore

Real time PCR to detect the environmental faecal contamination by Echinococcus multilocularis from red fox stools

The oncosphere stage of Echinococcus multilocularis in red fox stools can lead, after ingestion, to the development of alveolar echinococcosis in the intermediate hosts, commonly small mammals and occasionally humans. Monitoring animal infection and environmental contamination is a key issue in public health surveillance. We developed a quantitative real-time PCR technique (qPCR) to detect and quantify E. multilocularis DNA released in fox faeces. A qPCR technique using a hydrolysis probe targeting part of the mitochondrial gene rrnL was assessed on (i) a reference collection of stools from 57 necropsied foxes simultaneously investigated using the segmental sedimentation and counting technique (SSCT) (29 positive for E. multilocularis worms and 28 negative animals for the parasite); (ii) a collection of 114 fox stools sampled in the field: two sets of 50 samples from contrasted endemic regions in France and 14 from an E. multilocularis-free area (Greenland). Of the negative SSCT controls, 26/28 were qPCR-negative and two were weakly positive. Of the positive SSCT foxes, 25/29 samples were found to be positive by qPCR. Of the field samples, qPCR was positive in 21/50 (42%) and 5/48 (10.4%) stools (2 samples inhibited), originating respectively from high and low endemic areas. In faeces, averages of 0.1 pg/μl of DNA in the Jura area and 0.7 pg/μl in the Saône-et-Loire area were detected. All qPCR-positive samples were confirmed by sequencing. The qPCR technique developed here allowed us to quantify environmental E. multilocularis contamination by fox faeces by studying the infectious agent directly. No previous study had performed this test in a one-step reaction.

Ribosomal and mitochondrial DNA target for real-time PCR diagnosis of invasive aspergillosis

ABSTRACT The aim of the present study was to assess the diagnostic efficacy of a combination of two quantitative Aspergillus PCR assays, targeting a mitochondrial and a ribosomal target, in patients with risk factors for invasive aspergillosis (IA) and positive galactomannan (GM) antigen. Forty-four patients with hematological malignancies and risk factors for IA according to revised European Organization for Research on Treatment of Cancer and the Mycoses Study Group criteria (EORTC/MSG) criteria and presenting at least two sequential GM-positive sera were included in the study. Mitochondrial PCR was carried out prospectively on all GM-positive serum samples. Ribosomal PCR was carried out retrospectively on frozen stored sera. The sensitivities of mitochondrial and ribosomal PCRs were 58% and 50%, respectively. The diagnostic test performance was improved by using a combination of both PCR assays and by considering a patient PCR positive when at least two positive results were obtained. The sensitivity, specificity, and positive and negative likelihood ratios were 65%, 94%, and 11.8 and 0.37, respectively. A significant association between fatal outcome at 90 days and positive results of ribosomal PCR assays was observed (adjusted hazard ratio = 8.2; 95% confidence interval [CI] = 1.0 to 65.8; P = 0.048). Our results showed that the combination of two PCR assays targeting mitochondrial and ribosomal Aspergillus DNA improves the sensitivity of PCR in the diagnosis of IA in hematological patients with risk factors and positive GM results. This study also confirms that a positive PCR result is associated with a poor prognosis in these patients and should lead to specific antifungal therapy being introduced immediately.

The health and economic burden of bloodstream infections caused by antimicrobial-susceptible and non-susceptible Enterobacteriaceae and Staphylococcus aureus in European hospitals, 2010 and 2011: a multicentre retrospective cohort study

We performed a multicentre retrospective cohort study including 606,649 acute inpatient episodes at 10 European hospitals in 2010 and 2011 to estimate the impact of antimicrobial resistance on hospital mortality, excess length of stay (LOS) and cost. Bloodstream infections (BSI) caused by third-generation cephalosporin-resistant Enterobacteriaceae (3GCRE), meticillin-susceptible (MSSA) and -resistant Staphylococcus aureus (MRSA) increased the daily risk of hospital death (adjusted hazard ratio (HR) = 1.80; 95% confidence interval (CI): 1.34–2.42, HR = 1.81; 95% CI: 1.49–2.20 and HR = 2.42; 95% CI: 1.66–3.51, respectively) and prolonged LOS (9.3 days; 95% CI: 9.2–9.4, 11.5 days; 95% CI: 11.5–11.6 and 13.3 days; 95% CI: 13.2–13.4, respectively). BSI with third-generation cephalosporin-susceptible Enterobacteriaceae (3GCSE) significantly increased LOS (5.9 days; 95% CI: 5.8–5.9) but not hazard of death (1.16; 95% CI: 0.98–1.36). 3GCRE significantly increased the hazard of death (1.63; 95% CI: 1.13–2.35), excess LOS (4.9 days; 95% CI: 1.1–8.7) and cost compared with susceptible strains, whereas meticillin resistance did not. The annual cost of 3GCRE BSI was higher than of MRSA BSI. While BSI with S. aureus had greater impact on mortality, excess LOS and cost than Enterobacteriaceae per infection, the impact of antimicrobial resistance was greater for Enterobacteriaceae.

Molecular epidemiology of multidrug-resistant Pseudomonas aeruginosa in a French university hospital

The aim of this study was to assess the incidence and molecular epidemiology of multidrug-resistant (MDR) Pseudomonas aeruginosa in our university hospital. Analysis included antimicrobial susceptibility profiling, bla gene identification and pulsed-field gel electrophoresis (PFGE). During the one-year study, 654 patients had at least one sample that tested positive for P. aeruginosa, of whom 38 (5.8%) were colonised or infected with an MDR isolate, giving an incidence of 0.1 patient per 1000 patient-days. The 38 non-duplicate isolates yielded 12 different PFGE patterns, three of which included isolates from four patients and one of which included isolates from 15 patients. Two isolates produced acquired extended-spectrum β-lactamase (one OXA-14 and one OXA-28). Genotyping showed that cross-transmission was responsible for about 70% of MDR P. aeruginosa cases although spatio-temporal analysis failed to demonstrate when this might have occurred for most cases. The major epidemic and the three main micro-epidemic clones were already present in our hospital with a more susceptible phenotype. It is likely that some P. aeruginosa clones are endemic in our hospital and that, within these clones, MDR isolates emerge under antibiotic pressure. Our results indicate that cross-transmission plays a major role in the spread of MDR P. aeruginosa and suggest that priority should be given to the improvement of standard hygienic precautions.

Usefulness of antimicrobial resistance pattern for detecting PVL- or TSST-1-producing meticillin- resistant Staphylococcus aureus in a French university hospital

Several recent reports have suggested that community-associated meticillin-resistant Staphylococcus aureus (MRSA) clones, particularly those harbouring genes for Panton-Valentine leukocidin (PVL) or toxic shock syndrome toxin 1 (TSST-1), are increasingly responsible for infections in hospitals. Here, a retrospective study was carried out to investigate whether antimicrobial resistance patterns could be used to detect these pathogens in a French university hospital. Isolates were characterized by antimicrobial susceptibility testing, PCR profiling (PVL genes and tst), PFGE typing and multilocus sequence typing. Demographic and clinical data were collected from all patients. For PVL-positive MRSA, the typical antimicrobial resistance pattern (susceptible to fluoroquinolones, non-susceptible to fusidic acid, kanamycin resistant and susceptible to gentamicin and tobramycin) had a sensitivity of 77.8 % and a positive predictive value (PPV) of 100 %. For tst-positive MRSA, the antimicrobial resistance pattern (susceptible to fluoroquinolones and non-susceptible to fusidic acid) had a sensitivity of 100 % and a PPV of 72.4 %. These results suggest that phenotypic rules based on antimicrobial resistance patterns are potentially useful for the detection of PVL- and tst-positive MRSA isolates.

Antibiotic prescription in nursing homes for dependent elderly people: a cross-sectional study in Franche-Comté.

OBJECTIVES We had for objective to determine the rate of patients treated with antibiotics and the determinants of antibiotic stewardship in nursing homes for dependent elderly people (French acronym EHPAD), of a French region (Franche-Comté). PATIENTS AND METHODS A representative sample of EHPAD, in Franche-Comté, was included in a cross-sectional study made between April and June 2012. An external auditor and the EHPAD head physician collected data on the facility and on residents receiving antibiotics on the study day. An infectious diseases specialist and an infection control practitioner analyzed each prescription, a posteriori, to assess criteria of antimicrobial stewardship including re-assessment of the prescription between 48 and 72h after initiation of antibiotic treatment. RESULTS Sixty-one (2.76%) of the 2210 residents in 18 nursing homes were under antibiotic treatment. This rate ranged from 0% to 7.5% among nursing homes. Sixty-two percent of prescriptions complied with recommendations regarding the choice of the drug, and 41.5% could not be improved by choosing an agent with a weaker ecological impact. Globally, 17.8% of prescriptions met all stewardship criteria including re-assessment of the prescription between 48 and 72h after initiation of antibiotic treatment. CONCLUSIONS The study results differed. The rate of antibiotic prescription was low in Franche-Comté EHPAD compared to available European data, but antibiotic therapy could be greatly improved. This stresses the need to better train EHPAD physicians for antibiotic stewardship.

Marked increase in incidence for bloodstream infections due to Escherichia coli, a side effect of previous antibiotic therapy in the elderly

We conducted a survey including 3334 bloodstream infections (BSIs) due to E. coli diagnosed in 2005–2014 at a stable cohort of hospitals. Marked increases in incidence were observed for community-acquired (CA) BSIs in patients aged >75 years, CA-BSIs of digestive origin in patients aged 60–74 years, healthcare-associated BSIs, and BSIs associated with ESBL (extended-spectrum B-lactamase)-producing E. coli (ESBLEc). Using MLST, we studied the genetic diversity of 412 BSI isolates recovered during the 2014 survey: 7 major sequence type complexes (STCs) were revealed in phylogenetic group B2, 3 in group A/B1 and 2 in group D. Among the 31 ESBLEc isolates, 1/3 belonged to STC 131. We searched for possible associations between clonal groups, clinical determinants and characteristics of BSIs: isolates from groups B2 (except STC 131) and D were susceptible to antibiotics and associated with BSIs of urinary origin in patients <60 years. STC 131 and group A/B1 isolates were multi-drug resistant and associated with CA-BSIs of digestive origin in patients aged 60–74 with a recent history of antibiotic treatment. STC 131 isolates were associated with HCA-BSIs in patients with recent/present hospitalization in a long-stay unit. We provide a unique population-based picture of the epidemiology of E. coli BSI. The aging nature of the population led to an increase in the number of cases caused by the B2 and D isolates generally implicated in BSIs. In addition, the association of a trend toward increasing rates of gut colonization with multi drug-resistant isolates revealed by the rise in the incidence of BSIs of digestive origin caused by STC 131 and A/B1 (STCs 10, 23, and 155) isolates, and a significant increase in the frequency of BSIs in elderly patients with recent antibiotic treatment suggested that antibiotic use may have contributed to the growing incidence of BSI.

Comparison of the serological tests ICT and ELISA for the diagnosis of alveolar echinococcosis in France.

Serological diagnosis of alveolar echinococcosis (AE) is a key element for efficient patient treatment management. A rapid immunochromatography test kit (ICT) using the recombinant Em18 antigen (rEm18) was recently developed. The aim of our study was to assess this test on a panel of sera from French patients with alveolar echinococcosis and control patients. In a blind test, a total of 112 serum samples were tested including samples of AE (n = 30), cystic echinococcosis [CE] (n = 15), and polycystic echinococcosis [PE] (n = 1). For the comparison, 66 sera from patients with hepatocarcinoma, fascioliasis, toxocariasis, Caroli’s disease, or autoimmune chronic active hepatitis were used. The diagnostic test sets we used were the rEm18-ICT and two validated ELISAs with rEm18 and Em2-Em18 antigens, respectively. For the ICT, 27/30 sera from AE patients, 4/15 sera from CE patients and the PE patient serum were positive. One serum from the control panel (toxocariasis) was positive for the ICT. The rEm18-ICT sensitivity (90.0%) and specificity (92.7%) for detection of Em18-specific antibodies confirmed it as a relevant tool for AE diagnosis. The rEm18-ELISA had a sensitivity of 86.7% and specificity of 91.5%, and the Em2-Em18-ELISA had a sensitivity of 96.7% and specificity of 87.8%. However, when AE patient sera are recorded as weak in intensity with the ICT, we recommend a double reading and use of a reference sample if the ICT is used for patient follow-up.

A 10-year survey of fungal aerocontamination in hospital corridors: a reliable sentinel to predict fungal exposure risk?

BACKGROUND Invasive mould infections represent a threat for high-risk patients hospitalized in haematology units. French guidelines recommend that fungal aerocontamination monitoring should be performed quarterly. Since 2002, Besançon University Hospital has expanded to include several new buildings. Consequently, environmental surveys have been re-inforced and are now performed on a weekly basis. AIM To retrospectively assess the contribution of fungal aerocontamination measurement in haematology corridors and main hospital corridors as a sentinel to assess fungal exposure and risk of invasive mould infections. METHODS Over a 10-year period, 2706 air samples were taken by impaction every week in the same locations in haematology corridors and main hospital corridors. All fungal species were identified. The Haematology and Hospital Hygiene Departments were alerted systematically whenever a peak of opportunistic species was detected and corrective action was planned. Since 2007, each case of invasive aspergillosis has been reported to the French health authorities. Cuzicks test, Mann-Kendalls trend test, autocorrelation and Spearmans correlation rank test were used for statistical analysis. FINDINGS Over 10 years of surveillance, 12 peaks of Aspergillus fumigatus (>40 colony-forming units/m(3)) were observed in the main hospital corridors, and A. fumigatus contamination was detected up to six times per year in the haematology corridors. In order to limit fungal exposure, the decision was made to perform additional checks on ventilation systems and heating, increase biocleaning and develop clear instructions. CONCLUSION No significant link was observed between A. fumigatus detection and invasive aspergillosis. Weekly surveys have helped to improve the vigilance of the medical teams. Nevertheless, 58 cases of invasive aspergillosis have been identified since 2007.

Biocidal activity of metalloacid-coated surfaces against multidrug-resistant microorganisms

BackgroundThe antimicrobial effects of a coating of molybdenum trioxide (MoO3) has been recently described. The metalloacid material produces oxonium ions (H3O+), which creates an acidic pH that is an effective, non specific antimicrobial. We determined the in vitro antimicrobial activity of molybdenum trioxide metalloacid-coated surfaces.MethodsMetalloacid-coated and non-coated (control) surfaces were contaminated by exposing them for 15 minutes to microbial suspensions containing 105 cfu/mL. Eleven microorganisms responsible for nosocomial infections were tested: two Staphylococcus aureus strains (the hetero-vancomycin intermediate MRSA Mu50 strain and a ST80-PVL-producing MRSA strain); a vancomycin-resistant van A Enterococcus faecium strain; three extended-spectrum beta-lactamase-producing Enterobacteriaceae strains; a MBL-producing Pseudomonas aeruginosa strain; a multidrug-resistant Acinetobacter baumannii strain; a toxin-producing Clostridium difficile strain; and two fungi (Candida albicans and Aspergillus fumigatus). The assay tested the ability of the coated surfaces to kill microorganisms.ResultsAgainst all non-sporulating microorganisms tested, metalloacid-coated surfaces exhibited significant antimicrobial activity relative to that of the control surfaces within two to six hours after contact with the microorganisms (p < 0.001). Microorganism survival on the coated surfaces was greatly impaired, whereas microorganism survival on control surfaces remained substantial.ConclusionsWe suggest that, facing the continuing shedding of microorganisms in the vicinity of colonized or infected patients, the continuous biocidal effect of hydroxonium oxides against multidrug-resistant microorganisms may help limit environmental contamination between consecutive cleaning procedures.