Wastewater treatment plants release large amounts of extended-spectrum ß-lactamase-producing Escherichia coli into the environment.

BACKGROUND: The determinants of the spread of extended-spectrum ß-lactamase-producing Escherichia coli (ESBLEC) in the community remain unclear. To evaluate its dissemination in the environment, we analyzed the ESBLEC population throughout an urban wastewater network. METHODS: Samples were collected weekly, over a 10-week period, from 11 sites throughout the wastewater network of Besançon city (France). Total E. coli and ESBLEC loads were determined for each sample. As a control, we analyzed 51 clinical ESBLEC isolates collected at our hospital. We genotyped both environmental and clinical ESBLEC by pulsed-field gel electrophoresis and multilocus sequence typing and identified their blaESBL genes by sequencing. RESULTS: The E. coli load was higher in urban wastewater than in hospital wastewater (7.5 × 10(5) vs 3.5 × 10(5) CFU/mL, respectively). ESBLEC was recovered from almost all the environmental samples and accounted for 0.3% of total E. coli in the untreated water upstream from the wastewater treatment plant (WWTP). The ESBLEC load was higher in hospital wastewater than in community wastewater (27 × 10(3) vs 0.8 × 10(3) CFU/mL, respectively). Treatment by the WWTP eliminated 98% and 94% of total E. coli and ESBLEC, respectively. The genotyping revealed considerable diversity within both environmental and clinical ESBLEC and the overrepresentation of some clonal complexes. Most of the sequence types displayed by the clinical isolates were also found in the environment. CTX-M enzymes were the most common enzymes whatever the origin of the isolates. CONCLUSIONS: The treatment at the WWTP led to the relative enrichment of ESBLEC. We estimated that >600 billion of ESBLEC are released into the river Doubs daily and the sludge produced by the WWTP, used as fertilizer, contains 2.6 × 10(5) ESBLEC per gram.

Influenza outbreaks management in a French psychiatric hospital from 2004 to 2012.

OBJECTIVE: Influenza epidemics can have consequences in terms of morbidity and mortality for the patients. This work assesses influenza outbreaks in order to validate and optimize alert and control measures in a psychiatric hospital. METHOD: The prospective monitoring of influenza episodes was conducted for 8 years in 19 units of a mental health hospital. Rapid influenza diagnostic tests were used. The study of the episodes with confirmed influenza cases was carried out. RESULTS: Influenza monitoring and alert were essential with information and laboratory-confirmed cases. Influenza was common with a total of 20 episodes for the studied period. A maximum of 25% (5/20) of the units were affected in 2008-2009. Rapid influenza diagnostic tests allowed a quick identification with an average time of 1.5 days. Mainly, control measures limited the spread of the influenza virus in units with patient not at high risk of complications. On the other hand, antiviral curative treatment and chemoprophylaxis are essential in units with patients at high risk of complications. CONCLUSION: In a psychiatric hospital, influenza management has to take into account the exposed patient's risks for influenza complications and to adapt the strategy according to the risks identified.

Evaluation of the number of opportunities for hand hygiene in hospital: a new methodological approach.

OBJECTIVE: To assess the number of alcohol-based hand rubbing (ABHR) opportunities in different wards of a university hospital. MATERIALS AND METHODS: The amount of care procedures was measured in nine wards (4 medical wards, 4 surgical wards, 1 intensive care unit) over a two-year period. We converted the number of care procedures into a number of ABHR opportunities using the definition provided by the World Health Organization that takes in account the nature of the care procedure and the number of healthcare workers involved in. We compared these data with those obtained by other authors and the theoretical minimal number of ABHR opportunities defined by the French Ministry of Health. RESULTS: 1,252,671 care procedures (with a mean period of 734 days/department, 122,866 days of hospitalization and 21,905 patients) were converted into ABHR opportunities. The mean number of care procedures and ABHR per day and per patient was 6.1 and 35 for the medical departments, 7.6 and 49 for the surgery departments, 14.8 and 237 for the intensive care unit, respectively. CONCLUSION: Our methodological approach strengthens the results of previous observational studies. Here, we showed that the number of ABHR opportunities is far higher than that defined by the French Ministry of Health to measure the hand hygiene hospital endeavour.

Impact of a region wide antimicrobial stewardship guideline on urinary tract infection prescription patterns.

BACKGROUND: Fluoroquinolones are frequently prescribed for non complicated urinary tract infection treatments and have a negative ecological impact. We aimed to substitute them by antibiotics with narrower activity spectrum in order to preserve fluoroquinolone activity in complicated hospital infections. OBJECTIVE: To assess the impact of a multi-modal approach that combines the dispatching of antibiotic prescription guidelines and voluntary attendance at educational sessions on general practitioners' (GP) antibiotic prescription habits. SETTING: This study was led in Franche-Comté, a French eastern region, where GPs were given a guideline recommending a restricted use of fluoroquinolones for urinary tract infections. METHOD: Segmented regression analysis of interrupted time series was used to assess changes in antibiotic prescription. MAIN OUTCOME MEASURE: The antibiotic prescription data of nitrofurantoin, fosfomycin-trometamol and fluoroquinolones for women aged 15-65 years were obtained from the regional agency of health insurance. RESULTS: Twenty months after intervention, the number of nitrofurantoin and fosfomycintrometamol prescriptions increased by 36.8% (95% CI: 30.6-42.2) and 28.5% (95% CI: 22.9-35.4), respectively, while that of norfloxacin decreased by 9.1% (95% CI: -15.3 to -3.5). CONCLUSION: This study suggests that the dispatch of the guideline on urinary tract infection had a moderate impact on antibiotic prescriptions.

Tracking down antibiotic-resistant Pseudomonas aeruginosa isolates in a wastewater network.

The Pseudomonas aeruginosa-containing wastewater released by hospitals is treated by wastewater treatment plants (WWTPs), generating sludge, which is used as a fertilizer, and effluent, which is discharged into rivers. We evaluated the risk of dissemination of antibiotic-resistant P. aeruginosa (AR-PA) from the hospital to the environment via the wastewater network. Over a 10-week period, we sampled weekly 11 points (hospital and urban wastewater, untreated and treated water, sludge) of the wastewater network and the river upstream and downstream of the WWTP of a city in eastern France. We quantified the P. aeruginosa load by colony counting. We determined the susceptibility to 16 antibiotics of 225 isolates, which we sorted into three categories (wild-type, antibiotic-resistant and multidrug-resistant). Extended-spectrum ß-lactamases (ESBLs) and metallo-ß-lactamases (MBLs) were identified by gene sequencing. All non-wild-type isolates (n = 56) and a similar number of wild-type isolates (n = 54) were genotyped by pulsed-field gel electrophoresis and multilocus sequence typing. Almost all the samples (105/110, 95.5%) contained P. aeruginosa, with high loads in hospital wastewater and sludge (≥3×10(6) CFU/l or/kg). Most of the multidrug-resistant isolates belonged to ST235, CC111 and ST395. They were found in hospital wastewater and some produced ESBLs such as PER-1 and MBLs such as IMP-29. The WWTP greatly reduced P. aeruginosa counts in effluent, but the P. aeruginosa load in the river was nonetheless higher downstream than upstream from the WWTP. We conclude that the antibiotic-resistant P. aeruginosa released by hospitals is found in the water downstream from the WWTP and in sludge, constituting a potential risk of environmental contamination.

Methicillin-susceptible ST398 Staphylococcus aureus responsible for bloodstream infections: an emerging human-adapted subclone?

In the course of an annual 3-month bloodstream infections (BSI) survey conducted during a four-year period in 31 healthcare institutions located in three noncontiguous French regions, we report 18 ST398 Staphylococcus aureus BSI. ST398 BSI incidence showed a seven-fold increase during the study period (0.002 per 1,000 patient days in 2007 vs. 0.014 in 2010). ST398 BSI isolates differed from the pig-borne multiresistant clone: 17/18 BSI isolates were methicillin susceptible and none was of t011, t034 or t108 pig-borne spa-types. ST398 BSI isolates had homogenous resistance patterns (15/18 with only Ery(r)) and prophagic content (all harboured the hlb-converting Sau3int phage). The clustering of BSI and pig-borne isolates by spa-typing and MLVA, the occurrence of Sau3int phage in BSI isolates and the lack of this phage in pig-borne isolates suggest that the emergence of BSI isolates could have arisen from horizontal transfer, at least of the Sau3int phage, in genetically diverse MSSA ST398 isolates. The acquisition of the phage likely plays a role in the increasing ability of the lysogenic ST398 isolates to colonize human. The mode of acquisition of the non pig-borne ST398 isolates by our 18 patients remains unclear. ST398 BSI were diagnosed in patients lacking livestock exposure and were significantly associated with digestive portals of entry (3/18 [16.7%] for ST398 vs. 19/767 [2.5%] for non ST398 BSI; p = .012). This raises the question of possible foodborne human infections. We suggest the need for active surveillance to study and control the spread of this human-adapted subclone increasingly isolated in the hospital setting.

Most multidrug-resistant Pseudomonas aeruginosa isolates from hospitals in eastern France belong to a few clonal types.

This study aimed to determine the genetic diversity of clinical multidrug-resistant Pseudomonas aeruginosa. We used pulsed-field gel electrophoresis and multilocus sequence typing to analyze 187 strains isolated in different French hospitals. To illustrate the diversity of resistance mechanisms to antibiotics in a given clone, we identified ß-lactamases with an extended spectrum by using phenotypic and genotypic methods. Typing results showed that the majority of our multidrug-resistant isolates belong to a few clonal types (ST235, ST111, and ST175) that are already spreading worldwide. These successful international clones sporadically produced extended-spectrum ß-lactamase-encoding genes but mostly became extensively resistant to ß-lactams after derepression of intrinsic resistance mechanisms (i.e., AmpC cephalosporinase). Our results indicate that cross-transmission plays a major role in the spread of multidrug-resistant P. aeruginosa in hospital settings.

Impact of barrier precautions and antibiotic consumption on the incidence rate of acquired cases of infection or colonization with Acinetobacter baumannii: a 10-year multi-department study.

Following a previous investigation, this ecological study assessed the impact of barrier precautions and various factors on the annual incidence rate of acquired Acinetobacter baumannii cases in each of the 32 departments of the University Hospital of Besançon from 2000 to 2009. Ultimately, our study confirms the effectiveness of barrier precautions in addition to standard precautions for controlling A baumannii within our hospital departments. In comparison with the previous research, it emphasizes the significant role of fluoroquinolones in the emergence and the spread of this microorganism.

Nationwide investigation of extended-spectrum beta-lactamases, metallo-beta-lactamases, and extended-spectrum oxacillinases produced by ceftazidime-resistant Pseudomonas aeruginosa strains in France.

A nationwide study aimed to identify the extended-spectrum beta-lactamases (ESBLs), metallo-beta-lactamases (MBLs), and extended-spectrum oxacillinases (ES-OXAs) in a French collection of 140 clinical Pseudomonas aeruginosa isolates highly resistant to ceftazidime. Six ESBLs (PER-1, n=3; SHV-2a, n=2; VEB-1a, n=1), four MBLs (VIM-2, n=3; IMP-18, n=1), and five ES-OXAs (OXA-19, n=4; OXA-28, n=1) were identified in 13 isolates (9.3% of the collection). The prevalence of these enzymes is still low in French clinical P. aeruginosa isolates but deserves to be closely monitored.

Usefulness of weekly methicillin-resistant Staphylococcus aureus screening.

We evaluated the usefulness of adding weekly methicillin-resistant Staphylococcus aureus (MRSA) screening to our established admission screening and clinical sampling in 4 acute care units of a university hospital. Our results suggest that weekly MRSA screening allows the detection of 56.1% of all cases of hospital-acquired MRSA carriage. These cases would have remained undetected had admission screening and clinical sampling been the only types of surveillance in place.

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.

Ecological study of the effectiveness of isolation precautions in the management of hospitalized patients colonized or infected with Acinetobacter baumannii.

OBJECTIVE: To assess the impact of isolation precautions on the incidence of patients colonized or infected with Acinetobacter baumannii (case patients) in a university hospital during the period from 1999 to 2006. DESIGN: Ecological study. SETTING: The Besançon University Hospital in France, a 1,200-bed acute care hospital with approximately 50,000 admissions per year. METHODS: Using Poisson regression analysis, we evaluated a total of 350,000 patient-days to determine the annual incidence of case patients. This annual incidence was used as the outcome variable, and infection control practices, antibiotic use, and other aggregated data regarding patients' age, sex, McCabe score, and immune status were used as covariates. RESULTS: The implementation of isolation precautions was independently and negatively associated with the incidence of patients colonized or infected with A. baumannii (relative risk, 0.50 [95% confidence interval, 0.40-0.64]; P<.001). CONCLUSIONS: Our study suggests that the implementation of isolation precautions, in addition to standard precautions, effectively prevents the spread of A. baumannii in a hospital setting.

The role of water fittings in intensive care rooms as reservoirs for the colonization of patients with Pseudomonas aeruginosa.

OBJECTIVE: To assess the role of the water environment in the Pseudomonas aeruginosa colonization of patients in intensive care units in the absence of a recognized outbreak. DESIGN AND SETTING: Prospective, single-centre study over an 8-week period in two adult ICUs at a university hospital. Environmental samples were taken from the water fittings of rooms once per week, during a 8-week period. Patients were screened weekly for P. aeruginosa carriage. Environmental and humans isolates were genotyped by using pulsed-field gel electrophoresis. RESULTS: P. aeruginosa was detected in 193 (86.2%) of the 224 U-bend samples and 10 of the 224 samples taken from the tap (4.5%). Seventeen of the 123 patients admitted were colonized with P. aeruginosa. Only one of the 14 patients we were able to evaluate was colonized by a clone present in the water environment of his room before the patient's first positive sample was obtained. CONCLUSION: The role of the water environment in the acquisition of P. aeruginosa by intensive care patients remains unclear, but water fittings seem to play a smaller role in non-epidemic situations than expected by many operational hospital hygiene teams.

Relationship between antibiotic use and incidence of MexXY-OprM overproducers among clinical isolates of Pseudomonas aeruginosa.

In a university hospital, time-series analysis revealed a significant relationship between antibiotic (aminoglycoside, fluoroquinolone, and cefepime) use and incidence of MexXY-OprM-overproducing Pseudomonas aeruginosa. In vitro experiments confirm that such mutants were readily selected from both PAO1 and clinical strains when grown in the presence of these antibiotics.

Effect of individual- and group-level antibiotic exposure on MRSA isolation: a multilevel analysis.

OBJECTIVES: To observe the relative role of individual and group-level antimicrobial selective pressure on subsequent methicillin-resistant Staphylococcus aureus (MRSA) isolation in a university hospital. METHODS: For this purpose, 18 596 patients were included in a retrospective statistical analysis, applying multilevel modelling with discrete time intervals at the lowest level. Individual-level and hospital group variables on antimicrobial exposure and MRSA colonization pressure were collected from computerized databases. RESULTS: The simultaneous hospital group- and individual-level analysis showed individual exposure to fluoroquinolones and collective exposure to penicillins to be associated with MRSA isolation after adjustment for colonization pressure and other potential confounders. CONCLUSIONS: These results support efforts to reduce prescriptions of selected antimicrobial drug classes such as fluoroquinolones and show the added value of multilevel analysis for research on the adverse outcomes of antibiotic prescribing.