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.

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.

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.

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.

[Air cleanliness in operating rooms: on-site controls and biological testing]. / La maîtrise de la propreté de l'air des locaux opératoires: intérêt des mesures en activité et des examens microbiologiques.

Air cleanliness control in operating rooms is based on air filtration, and targets the lowest density of particules and bacteria. Legally, the equipment must be periodically verified during periods of inactivity. Most airborne bacteria are of human origin. There is no fixed ratio between the particle count and the level of bacterial contamination. A study of different types of operating room at Besançon Medical Center reached the following conclusions:--Controls are also required during periods of activity.--Bacteriological testing is crucial.--Unidirectional airflow, especially of the horizontal type, is superior to other forms of isolation. The authors propose a "Functionality index", calculated as follows: bacterial count during use of the room minus bacterial count during non use/the number of people in the room. Efficient equipment would have a low index, which would be unmodified by the number of persons present.

Estimation of the cumulative incidence of hospital-acquired bacteremia from prevalence data: a formula.

We evaluated the validity of the formula of Rhame and Sudderth to estimate the cumulative incidence of nosocomial bacteremia from prevalence studies. The observed cumulative incidence was threefold higher than the calculated cumulative incidence. We do not recommend converting prevalence into incidence data for nosocomial bloodstream infections.

Use of intranasal mupirocin to prevent methicillin-resistant Staphylococcus aureus infection in intensive care units.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) causes severe morbidity and mortality in intensive care units (ICUs) worldwide. The purpose of this study was to determine whether intranasal mupirocin prophylaxis is useful to prevent ICU-acquired infections with MRSA. MATERIALS AND METHODS: We conducted a 4-year observational retrospective study in a 15-bed adult medical ICU. During the first 2-year period mupirocin ointment was included in the MRSA control programme; during the second, mupirocin was not used. The main endpoint was the number of endogenous ICU-acquired infections with MRSA. RESULTS: The number of endogenous acquired infections was significantly higher during the second period than during the first (11 versus 1; P = 0.02), although there was no significant difference in the total number of patients infected with MRSA between the two periods. We also observed that nasal MRSA decolonisation was significantly higher in the mupirocin period than in mupirocin-free period (P = 0.002). CONCLUSION: Our findings suggest that intranasal mupirocin can prevent endogenous acquired MRSA infection in an ICU. Further double-blind, randomised, placebo-controlled studies are needed to demonstrate its cost-effectiveness and its impact on resistance.

Relationship between spread of methicillin-resistant Staphylococcus aureus and antimicrobial use in a French university hospital.

The objective of our study was to determine whether antibiotic pressure in the units of a teaching hospital affects the acquisition of methicillin-resistant Staphylococcus aureus (MRSA), independently of the other collective risk factors previously shown to be involved (MRSA colonization pressure, type of hospitalization unit, and care workload). The average incidence of acquisition of MRSA during the 1-year study period was 0.31 cases per 1000 days of hospitalization, and the use of ineffective antimicrobials reached 504.54 daily defined doses (DDDs) per 1000 days of hospitalization. Univariate analysis showed that acquisition of MRSA was significantly correlated with the use of all antimicrobials, as well as correlated with the use of each class of antimicrobial and with colonization pressure. Multivariate analysis with a Poisson regression model showed that the use of antimicrobials was associated with the incidence of acquisition of MRSA, independently of the other variables studied, but it did not allow us to determine the hierarchy of the different antimicrobial classes with respect to the effect.

Control of Enterobacteriaceae producing extended-spectrum beta-lactamase in intensive care units: rectal screening may not be needed in non-epidemic situations.

OBJECTIVE: To evaluate the usefulness of screening cultures in the control of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in intensive care units (ICUs). DESIGN: A 4-year retrospective study. SETTING: Two adult ICUs of a university-affiliated public hospital in France. RESULTS: A total of 7,777 specimens were analyzed and 28 (0.97%) of 2,883 screened patients had a positive result on a screening test, among the 3,678 admitted patients. Thirteen of these 28 patients were only carriers; 4 were carriers and then were colonized or infected 2, 2, 3, and 8 days later, respectively; and 11 were colonized or infected before a screening test was positive. Cluster analysis showed that the occurrence of ESBL-producing Enterobacteriaceae cross-transmission within both ICUs was limited to 9 cases. Thus, most cases (19 of 28) were probably imported. Surveillance cultures failed to detect 9 of the 19 cases. CONCLUSION: The low prevalence of ESBL-producing Enterobacteriaceae carriers on admission (0.45%) and the relative ineffectiveness of our screening test to detect imported cases suggest that systematic detection of ESBL-producing Enterobacteriaceae in ICU patients is not cost-effective and that the use of clinical cultures may be sufficient to control ESBL-producing Enterobacteriaceae in non-epidemic situations.

Contamination of trypan blue with Burkholderia cepacia in a cornea bank.

OBJECTIVE: To describe Burkholderia cepacia contamination of a cornea bank and the measures taken to identify and eliminate the source of infection. METHODS: Cultures were performed to assess the extent and source of contamination, and pulsed-field gel electrophoresis was used for molecular typing. RESULTS: Routine surveillance cultures identified 5 contaminated corneas during a 10-day period. Additional cultures showed that 28 of 88 samples were positive for this organism. Environmental investigation showed that an open bottle of trypan blue used to assess corneal morphology was contaminated with the epidemic strain. CONCLUSION: Trypan blue played a major role in this contamination of corneas. This episode shows that microbial contamination can affect transplanted corneas despite ongoing culture surveillance and suggests that new methods may be needed to avoid this risk.

First report of a catalase-negative methicillin-resistant Staphalococcus aureus.

We report the first case of catalase-negative methicillin-resistant Staphylococcus aureus. The isolated strain had phenotypic and genotypic characteristics of the major epidemic clone spreading in our region with the exception that catalase activity could not be found.

Relationship between molecular epidemiology and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) in a French teaching hospital.

The objective of this study was to investigate the relationship between molecular epidemiology and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus (MRSA) over a period of 4 years. The antibiotype of all MRSA isolates that were identified during a yearly period of 3 months was determined; 50 consecutive non-replicate MRSA isolates were typed each year. Susceptibility rates to gentamicin, tobramycin and ofloxacin remained stable (95, 16 and 4 %, respectively). In contrast, the proportion of MRSA isolates susceptible to erythromycin increased progressively from 10.5 to 32.5 % (P < 0.001). PFGE analysis of genomic DNA from 200 isolates revealed the presence of 15 different clones. Two epidemic clones were identified, which contained 150 (clone A) and 28 (clone C) isolates. Non-epidemic strains were more frequently susceptible to ofloxacin (31.8 versus 1.1 %) and tobramycin (45.4 versus 16.8 %) than epidemic strains; those isolates that were susceptible to all antibiotics tested belonged to sporadic clones. The increase of erythromycin susceptibility within MRSA isolates was caused by the emergence of clone C. This study suggests that when selection pressure exerted by an antibiotic is insufficient (i.e. below a threshold level), fitness advantages play a predominant role in the dissemination of MRSA clones. The balance between the selection pressure exerted by antibiotics and the disadvantage of lower replication rates of resistant strains in the absence of antibiotics complicates the biological model of clonal dissemination of epidemic MRSA strains.

Bacterial contamination of a cornea tissue bank: implications for the safety of graft engineering.

PURPOSE: To analyze the difficulties involved in managing an episode of bacterial contamination in a cornea bank. We describe (1) the circumstances of bacterial contamination discovery, (2) the methods used to investigate the outbreak, (3) the corrective measures adopted, and (4) the method introduced to improve the reaction capacity in case of bacterial contamination. METHODS: All the samples collected were cultured in an attempt to identify the environmental reservoir of the contaminated epidemic clone. Bacteria were identified by Gram stain, oxidase test, and biochemical characteristics. The clonality of the strains was assessed by pulsed-field gel electrophoresis. RESULTS: The bacterial contamination was confirmed for 28 corneas, and 70 additional corneas were discarded. The source of the contamination was identified 17 days after the beginning of the episode. It consisted of a clonal bacterial strain that was found in trypan blue, the dye, used to examine all the tissues. The contaminating bacterium was Burkholderia cepacia, a well-known nosocomial pathogen. A total of 169 grafted corneas had been checked with the contaminated reagent. No cases of post-graft infection were recorded. CONCLUSION: Trypan blue played a major role in this outbreak. The mode and chronology of contamination remain unresolved. This exceptional event emphasizes the risk of bacterial contamination in tissue/cell banks, the necessity to improve methods for its prevention, and procedures to limit its consequences.

Methicillin-resistant Staphylococcus aureus (MRSA) in rehabilitation and chronic-care-facilities: what is the best strategy?

BACKGROUND: The risk associated with methicillin-resistant Staphylococcus aureus (MRSA) has been decreasing for several years in intensive care departments, but is now increasing in rehabilitation and chronic-care-facilities (R-CCF). The aim of this study was to use published data and our own experience to discuss the roles of screening for MRSA carriers, the type of isolation to be implemented and the efficiency of chemical decolonization. DISCUSSION: Screening identifies over 90% of patients colonised with MRSA upon admission to R-CCF versus only 50% for intensive care units. Only totally dependent patients acquire MRSA. Thus, strict geographical isolation, as opposed to "social reinsertion", is clearly of no value. However, this should not lead to the abandoning of isolation, which remains essential during the administration of care. The use of chemicals to decolonize the nose and healthy skin appeared to be of some value and the application of this procedure could make technical isolation unnecessary in a non-negligible proportion of cases. SUMMARY: Given the increase in morbidity associated with MRSA observed in numerous hospitals, the emergence of a community-acquired disease associated with these strains and the evolution of glycopeptide-resistant strains, the voluntary application of a strategy combining screening, technical isolation and chemical decolonization in R-CCF appears to be an urgent matter of priority.

[The importance of isolating septic patients in an autonomous unit in orthopedic surgery and traumatology]. / L'intérêt de l'isolement en secteur autonome des patients septiques, en chirurgie orthopédique et traumatologique.

UNLABELLED: To examine whether Sepsis Containment Units are presently in use by French Orthopedic surgeons in a number of hospitals and the subsequent efficacy of these measures in the prevention of risks linked to methicillin resistant Staphylococcus aureus (MRSA), MRSA was used as an example because it is the bacteria most frequently associated with infection in orthopedics. The transient carriage of MRSA on the hands of hospital personnel is the most common mechanism of patient to patient transmission. Consequently, the incidence of nosocomial MRSA in patients can be used to assess the quality of infection control. SETTING: The orthopaedic surgery department (104 beds) of a 1. 228 bed, university affiliated public hospital located in eastern France (Besançon). METHODS: First: a questionnaire was sent out to 71 French university orthopedic departments to investigate the practice in place. Second: to establish whether a significant correlation exists between the colonisation pressure exerted by real imported MRSA, and the number of cases of real acquired MRSA since we know that colonisation pressure of bacteria is a major factor in the prognosis of clinical infection. Third: our orthopedic surgery department was redesigned to study the risks of colonisation pressure with or without Sepsis Containment Units. RESULTS: First: among the 71 orthopedic departments studied, only 11 used a Sepsis Containment Unit. Second: there is a definite, linear relationship between the colonisation pressure exerted in a unit by real imported MRSA and the number of cases of real acquired clinical infection. Third: in the absence of Sepsis Containment Units, the risk of MRSA infections is increased by 160%. Debat: the classical clinical arguments concerning the dangers of hand or aerobic MRSA transmission are confirmed by our figures. The strict use of Sepsis Containment Units prevents contamination of septics by septics. Inversely, the rigorous concentration of means in the Sepsis Containment Units also prevents cross contamination of septics. At question are the psychological and financial inconveniences of Sepsis Containment Units. The results of this experiment, performed in orthopedic surgery, show that the use of Sepsis Containment Units is just as critical in other surgical units: vascular, thoracic, etc., nor should they be overlooked in outpatient and emergency care--often the first step in orthopedic surgery. CONCLUSION: Sepsis Containment Units are essential and merit further development.

[Prophylactic antibiotics in urological surgery: compliance of prescriptions in Franche-Comté with national guidelines]. / L'antibioprophylaxie en chirurgie urologique: conformité des prescriptions par rapport au référentiel national en Franche-Comté.

STUDY OBJECTIVE: To evaluate prophylactic antibiotic practices in urological surgery in Franche-Comté. MATERIAL AND METHODS: Six urological surgery teams participated in data collection. Practices were evaluated in comparison with national guidelines by means of five questions: Did the surgical operation justify prophylactic antibiotics and was this treatment administered? Was the antibiotic selected that recommended by national guidelines? Was the total duration appropriate? Was the time of the first injection appropriate? Was the dosage appropriate? The Société Française d'Anesthésie et de Réanimation (SFAR) guidelines, revised in 1999, constituted the reference. RESULTS: Of the 213 operations included in the study, 134 corresponded to Altemeier class 1 and 2 operations for which the SFAR has issued guidelines. The overall compliance rate was 22.6%. Among the 56 patients who did not receive the recommended molecule, 45 received a molecule with a broader spectrum of activity than that of the recommended molecule. The duration of prophylactic antibiotics was longer for 10 of the 11 patients in whom the duration of prophylaxis did not comply with guidelines. Finally, for more than one third of operations, the time of injection of the first dose was not optimal. CONCLUSION: This study demonstrated the high frequency of non-compliance with prophylactic antibiotic prescription guidelines in urological surgery in Franche-Comté. These guidelines must be reinforced and applied to ensure the efficacy of prophylactic antibiotics and to avoid the emergence of resistant strains.

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.