Biomedical subjects
Publications and source records attributed to M Eveillard.
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To differentiate imported and acquired strains of methicillin-resistant Staphylococcus aureus (MRSA), a 48-hour delay from hospital admission to the first MRSA-positive culture is usually considered. To assess if taking into account this delay without any other consideration is an accurate method, we defined 3 situations for whom we considered the MRSA acquisition status as questionable. The other situations were defined as either acquired MRSA or imported MRSA. We determined the acquisition status of MRSA (acquired, imported, or questionable) isolated during a 20-month period by considering or not considering screening samples performed on admission. The ratio "imported MRSA/acquired MRSA" (I/A) was calculated according to (1) the consideration of MRSA with questionable status as imported or acquired, and (2) the consideration of screening samples or not in the calculation of the ratio. The acquisition status in our hospital was questionable in 3.6% of patients when all samples were considered and in 12,0% when only clinical samples were taken into account (p = 0,01). The ratio I/A was 4-fold higher by considering both clinical and screening cultures and questionable status as imported than by considering only clinical samples and questionable status as acquired. Using a 48-hour delay without any other consideration is probably an accurate method to differentiate acquired and imported MRSA when a selective screening programme at admission in operational. Conversely, this definition seems to be more hazardous in the absence of screening.
Identification of the meticillin-resistant Staphylococcus aureus (MRSA) reservoir by active screening followed by the implementation of contact precautions is one of the major components of MRSA control programmes. The objective of this study was to evaluate the results of a programme of selective screening in an emergency department (ED) and the appropriateness of the contact precautions implemented. This was estimated by distinguishing necessary and unnecessary days of contact precautions. This estimation was performed for all days of contact precautions and, more specifically, for days of preventive contact precautions implemented before the availability of screening results. During a three-year period, screening of MRSA carriers was performed on 0.95% (N=605) of patients visiting the emergency ward. Among the 193 (31.9%) MRSA carriers identified, 159 were hospitalized in the short-length-hospitalization area (SLHA) of the ED and/or in other wards. Among the 140 patients admitted to the SLHA, 44 were hospitalized for at least 48 h, with a mean length of hospitalization of 5.9 days. The cumulative duration of hospitalization of carriers identified by screening was 1897 days. In total, 2370 days of contact precautions (including 924 days of preventive precautions) were implemented for patients screened in the ED. Considering the whole hospital, the appropriateness of this entire programme of contact precautions for patients screened in the ED was 80.0% (52.1% for the SLHA), whereas the specific appropriateness of preventive isolation days was 48.6% (43.6% for the SLHA). This study underscores the risk of MRSA cross-transmission in the SLHA, and the usefulness of implementing a control programme of screening carriers in the ED.
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We evaluated the impact of the different components of a screening programme of methicillin-resistant Staphylococcus aureus (MRSA) carriers at hospital admission on the value of two risk-adjusted rates: the proportion of imported MRSA and an indicator of the MRSA colonization pressure (ICP), and the incidence of MRSA acquired and detected in our hospital. Indicators were calculated: (1) with no screening programme; (2) with a programme limited to the intensive care unit (ICU); (3) with a programme extended to patients with risk factors for MRSA carriage hospitalized in non-ICU wards. The programme included an automatic alert. Systematic sampling of patients with risk factors hospitalized in non-ICU settings detected nearly 50% of carriers at admission. The proportion of MRSA imported into our hospital varied from 35.4% without any screening programme to 71.8% when all components of our screening programme were considered (P<10(-4)). The ICP varied from 3.1% (31/985) with the complete programme to 10.4% (31/297) without any screening programme (P<10(-6)). Screening patients with risk factors for MRSA carriage hospitalized in non-ICU wards resulted in a 51% increase of the calculated proportion of imported strains and a 58% decrease of the ICP. The two studied indicators were strongly dependent on the screening strategy for MRSA carriers implemented at admission. The screening strategy for patients admitted to non-ICU wards who have risk factors for MRSA carriage seems to be the determinant for the interpretation of certain risk-adjusted indicators of MRSA cross-transmission. Comparisons of these indicators must consider the setting in which the screening programmes are implemented.
Our objective was to evaluate the accuracy of a methicillin-resistant Staphylococcus aureus (MRSA) rate using the imported MRSA reservoir identified at the time of hospital admission. Two indicators were used: the number of imported MRSA patient-days/total number of patient-days [representing colonization pressure (CP) at the time of admission] and the incidence of hospital-acquired MRSA isolated from clinical samples expressed as density/100 patient-days for carriers identified at the time of admission [representing the incidence taking CP into account (ICP)]. The variations of these indicators were analysed and compared with two more common indicators: percentage of MRSA acquired in our hospital and the incidence of hospital-acquired MRSA isolated from clinical samples expressed as density/1000 patient-days within three four-month periods during 2002. Common indicators varied similarly, with marked decline during the third period; first-period CP was twice that of other periods (P<10(-6)) and the highest (>two-fold) ICP was seen in the summer (second) period (P<0.001) when the personnel/patient ratio was the lowest. Thus, comparison of different indicators within four-month periods underlines important differences between common and novel indicators. Despite several limitations, ICP should be helpful in the interpretation of MRSA surveillance data, particularly for estimating the extent of MRSA transmission.
Deep wound infection is a rare but dreaded postoperative complication after total hip prosthesis (THP) procedures but its incidence can be reduced by systemic antimicrobial prophylaxis. The objective of the present study was to evaluate whether antimicrobial prophylaxis for elective primary THP in patients without any history of hip infection, in orthopaedic wards, participating on a voluntary basis, in French public hospitals and private institutions, complies with published guidelines. Three types of data were collected from anaesthetic and surgical records (November 2000-January 2001) in participating hospitals: (1) administrative data on the hospitals and orthopaedic wards, (2) data on patients, (3) data on compliance of practices with five critical criteria derived from published French guidelines. These criteria concerned administration of prophylaxis, choice of antimicrobial agent, dose of first injection, timing of administration and total length of prophylaxis. Thirty institutions sent data files on 1257 THPs to the coordination centre. Compliance exceeded 80% for all criteria except one (interval between first and second injection). Cumulative compliance with the five criteria was 66.9%. Major compliance failures were an inappropriate interval between the first injection and incision, and total antimicrobial prophylaxis exceeding 48 h. Cumulative compliance was 87.9% in teaching hospitals, 61.8% in general hospitals and 67.7% in private institutions (P<1 x 10(-6)). It was slightly higher when the annual number of interventions was > or =100 (69.4 versus 62.3%; P<0.02). Although the protocol for antimicrobial prophylaxis in THP was clear and easy, one-third of practices did not conform with all five standards. Knowledge of the results by the participating institutions should encourage them to set up working groups to draft care protocols for THP and other surgical interventions, in order to improve practice and perhaps reduce costs.
The aim of this study was to evaluate the number of deaths associated with nosocomial infections (NI) and the contribution of these NI to death. A multicentre descriptive study was conducted in 16 tertiary-care hospitals (14 222 beds) in Northern France. Medical records of consecutive patients who died at least 48 h after admission were reviewed for cause of death, NI and disease severity, before admission and before NI onset. The contribution of NI to death was assessed by agreement between two physicians according to a three-category scale of probability. Among the 1945 patients who died during the study, 26.6% had an NI. According to the agreed diagnosis, NI contributed to the deaths of 284 (14.6%) patients(certainly for 6.6% and possibly for 8%), thereby ranking NI as the fourth most frequent cause of death. Considering the deaths that had not been anticipated independently of NI two weeks before they occurred, NI definitely contributed to 2.8% of them. Lower respiratory tract, bloodstream and surgical wound infections were responsible for 39, 20 and 14%, respectively,of all NI in these patients. The impact of NI on in-hospital mortality seems to be lower than had previously been estimated in France based on US data from the 1970s and 1980s. To improve healthcare quality, further studies are needed to elucidate the processes that may contribute to fatal severe NI.
Methicillin-resistant Staphylococcus aureus (MRSA) constitute the most important multiresistant bacteria (MRB) recovered in French hospitals. Our objective was to measure these MRSA diffusion in our hospital to evaluate the MRB control programme which had been implemented in the beginning of 1999. This study was conducted in a teaching hospital containing 1800 beds, from February 1999 to January 2001. All MRSA isolated in clinical samples were included. Duplicates (same bacteria in the same patient) were excluded. The detection of methicillin-resistance was performed at 30 degrees C, by disk diffusion method. Incidence densities were determined with their 95% confidence interval (CI 95%). Their evolution by four-month period was evaluated with the chi-square test for trend. During the two-year period, 866 MRSA were isolated. The global incidence was 0,88 per 1000 patient-days (PD) (IC 95% = left open bracket 0,83-0,93 right open bracket ). For cases acquired in our hospital the incidence was 0,66 per 1000 PD, whereas it was 0,26 per 1000 PD for imported cases. Concerning the evolution of incidences, no significant trend was observed for global incidence. The incidence of acquired MRSA decreased during the first year, but increased thereafter. The incidence of imported MRSA increased with a significant trend (p < 10(-5)). The number of these imported MRSA isolated in our hospital was twice fold higher in 2000. This study emphasizes an important actual problem : the increase of patient colonization pressure at the time of admission in hospitals. This increase, which can be due in part to a community transmission, is responsible for a reduction of the efficacy of MRSA control programmes.
Studies on methicillin-resistant Staphylococcus aureus (MRSA) in the elderly have been concerned with patients hospitalized in nursing homes or long-term care facilities. Our objective was to estimate the prevalence of MRSA at the time of admission in two acute geriatric wards with high endemic MRSA incidence in a French teaching hospital. A prospective screening of MRSA carriers was conducted by swabbing nares and wounds during five weeks for all patients on the day of admission. For each patient demographic, administrative, clinical and therapeutic data were recorded. Their associations with MRSA carriage were studied by logistic regression analysis. On the day of admission, 35 patients (14.6%) were MRSA carriers. Variables independently associated with carriage were hospitalization within the six last months (OR = 4.64; P < 0.001) and the existence of wounds or bedsores (OR = 2.864; P = 0.02). The high prevalence of MRSA carriage at the time of admission could explain in part the high incidence of MRSA in these wards. A systematic selective screening targeted on patients with high risk of carriage should be helpful to implement barrier precautions and reduce cross-transmission.
OBJECTIVE: Deep infections of the operative site is a rare but serious complication of first intention total hip arthroplasties. French data on infections are sparse. We studied the incidence, characteristics and potential risk factors for these infections in a consecutive series of 790 total hip arthroplasties performed as first intention implantations in a University Hospital in France. PATIENTS AND METHODS: All patients undergoing first intention total hip arthroplasty surgery between November 1995 and May 1999 were included in this study. Demographic, clinical, therapeutic and surgical data were collected. Deep infection was defined as proven presence of microorganisms in at least two preoperative samples during revision surgery. Patients were followed for 1 month to 4 years. Potential risk factors were identified with univariate analysis. Chi square and exact Fisher test were used. RESULTS: The overall incidence of deep infections was 1.11 per 100 implantations (95% CI 0.84-2.70). Delay to development ranged from 14 days to 32 months. Eleven infections were proven within the first year and 3 after one year. Two risk factors were identified: absence of systemic antibiotic prophylaxis (RR = 4.74, p = 0.03) and drainage discharge after 48 hours (RR = 3.62, p = 0.02). Other variables associated with infection with a relative risk greater than 2 were obesity, corticosteroid therapy, development of a hematoma, or difficult postoperative wound healing. CONCLUSION: The incidence observed in this series is slightly higher than generally reported in the world literature. It would be important to write an antibiotic prophylaxis protocol with prescription of systemic antibiotics for all operated patients in order to reduce this incidence. Other measures that could improve the quality of care should also be taken: re-evaluation of preoperative skin preparation protocols, systematic screening of patients carrying Staphylococcus aureus before implantation and proper care for these patients.
Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLE) constitute with methicillin-resistant Staphylococcus aureus the main multiresistant bacteria recovered in French hospitals. Our objectives were to evaluate these ESBLE diffusion in our teaching hospital and to follow their incidence during a 16-month period, whereas a control programme (barrier precautions) had been implemented in the beginning of 1999. This study was conducted in a teaching hospital containing 1800 beds, from February 1999 to May 2000. All ESBLE isolated in clinical or screening samples were included. Duplicates (same bacteria in the same patient) were excluded. The detection of the ESBL was performed with the double-disk diffusion test. Incidence densities were determined with their 95% confidence interval (CI95%). Their evolution by four-month period was evaluated with the chi-square test for trend. During the 16-month period, 229 ESBLE were isolated. The incidence was 0.35 per 1000 patient-days (PD) (CI95% = [0.30-0.40]) for the whole hospital. It was 0.47/1000 PD (CI95% = [0.38-0.56]) in medical wards, 0.29/1000 PD (CI95% = [0.20-0.38]) in surgical wards and 1.32/1000 PD (CI95% = [0.90-1.74]) in intensive care units. Enterobacter aerogenes strains represented more than 75% of all ESBLE, whereas Klebsiella pneumoniae stains represented only 8.6%. During the study, the incidence of ESBLE and the proportion of strains acquired in our hospital decreased significantly (p < 0.0001 and p < 0.001 respectively). Indeed, between the first eight-month period and the last one, the incidence of ESBLE acquired in our hospital decreased by 55%, whereas the incidence of imported strains increased slightly. This study shows that the diffusion of ESBLE concerns the entire hospital. The implementation of a control programme of the spread of multiresistant bacteria allowed us to reduce significantly the incidence of ESBLE. This incidence seemed to be stable for several months. The implementation of a policy which restricts antimicrobial use would allow us to complete the the efficacy of barrier precautions.
From February 1999 to January 2000, a control programme to prevent the spread multi-resistant bacteria (MRB) was implemented in a French teaching hospital. This programme focused on methicillin-resistant Staphylococcus aureus (MRSA) and Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBL), and was based on the application of barrier precautions (washing hands with antiseptic soaps, wearing disposable gloves and gowns, identifying MRB carriers). No changes in antibiotic policy occurred during the year. Our aim was to conduct an evaluation of this programme by measuring incidence rates. Concurrently, the effect of barrier precautions was estimated in an indirect way, by documenting the availability of barrier precautions in MRB carriers' rooms and by analysing the monthly correlation between the supply of such material and the theoretical cumulated length of MRB carriers' isolation in six randomized wards. All MRB isolated in hospitalized patients were recorded, and differentiated between acquisition in our hospital or from elsewhere. For the analysis of trends, the year was divided in three periods of four months. Over the year, the global MRB incidence was 1.26 per 1000 patient-days (PD) [95% confidence interval (95%CI)=1.16-1.36]. The MRSA incidence was 0.89 per 1000 PD (95%CI=0.81- 0.97) and the ESBL incidence was 0.38 per 1000 PD (95% CI=0.33-0.43). The MRB incidence decreased significantly in all types of specialties except for surgical wards. The incidence decreased by 17.9% for MRSA, 54.9% for ESBL and 34.8% for both MRB. Concurrently, the proportion of strains acquired in our hospital decreased for MRSA (P for trend > or = 0.05) and ESBL (P for trend > or = 0.01), whereas the incidence of imported strains increased slightly. The proportion of multiresistant strains in S. aureus (36.8%) and Enterobacter aerogenes (37.0%) remained similar throughout the year. Thus, the decrease of the incidence concerned both resistant and susceptible strains. The availability of antiseptic soaps increased significantly (P for trend > or = 0.01). The amount of antiseptic soap ordered and the theoretical lengths of isolation were correlated on a monthly basis (Spearman coefficient = 0.72; P > or = 0.02). These results shows the efficacy of such a programme of MRB containment in a large hospital, provided barrier nursing is instigated, together with the availability of such material as antiseptic soap, to allow implementation.
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OBJECTIVE: To assess the risk of nosocomial infection in transferred patients and to determine whether transfer is only a risk marker or is independently associated with nosocomial infection. DESIGN: Retrospective analysis. SETTING: A 400-bed general hospital in the Paris area. PATIENTS: All the patients hospitalized on the days of the surveys were included. METHODS: Epidemiological analysis of data collected in four annual nosocomial infection prevalence surveys conducted between 1993 and 1996. RESULTS: Of the 1,326 patients included in the four surveys, 70 (5.3%) had been transferred from another hospital and 199 (15.0%) from another ward of our hospital. Transferred patients more frequently had known risk factors of nosocomial infection: age >65 years (P<10(-5)), a length of hospital stay >7 days on the day of the survey (P<10(-6)), at least one invasive procedure (34.2% vs 27.2%; P<.05), a recent surgical intervention (P<.05), and an immunosuppression (P<.01). The prevalence rate of infected patients was 6.7% (95% confidence interval, 5.3-8.1). The risk of being infected on a given day was more than 4 times higher in transferred patients (P<10(-6)); however, the risk was similar between patients transferred from another hospital (20.0%) and patients transferred within the hospital (17.1%). The multivariate analysis performed by logistic regression showed that intrahospital transfer, a length of hospital stay >7 days, and having had at least one invasive procedure were independent risk factors of infection. CONCLUSION: According to this study, patient transfer is both a risk marker (associated with several known risk factors) and independently associated with nosocomial infection. The origin of a transferred patient is readily known at admission. It would be useful to adopt specific measures for such patients, particularly if they have other risk factors of nosocomial infection, both to protect them and to prevent transmission of the infection to other hospitalized patients.
OBJECTIVES: To evaluate the ability of a new apparatus (Dipsys 25, Société SGN, Bagnols sur Cèze, France) to disinfect biomedical waste, including both potentially infectious agents and the normal saprophytic flora of the waste. METHODS: Disinfection was assessed using standard methods (reference strains were fixed on reference carriers according to the French AFNOR methods) and nonstandard assays. Assays in conditions of hospital use, evaluations of bacterial survival during storage, sporicidal effect, and spore survival during storage were performed in parallel. Finally, bactericidal effect in extreme conditions (association of high contamination and high bacterial protection conditions) was tested with normal fecal flora. Bacterial counts were performed after treatment by the apparatus and without treatment (controls). All tests were carried out in triplicate. RESULTS: In all treated carriers, a bacterial population decrease of at least 5 log10 was obtained. Assays performed in hospital-use conditions did not show any bacterial growth. Concerning the evaluation of sporicidal effect and spore revival during conservation, a minimum reduction of 5 log10 was observed in all assays performed, without survival. Finally, concerning assays in extreme conditions, the decrease of bacterial population was between 5 log10 and 10 log10 for vegetative anaerobes of normal fecal flora. CONCLUSION: Under our study conditions, the study apparatus reduced the tested microbial populations by a minimal factor of 5 log10. The main advantage of the apparatus is the opportunity to treat contaminated waste inside hospital wards, at the point of initial collection, without pulverization, by nonspecialized staff.
In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years. All extended-spectrum beta-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing. Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients. Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996. This study shows that TEM-24-producing E. aerogenes is an epidemic clone that is well established in the hospital's ecology and able to spread throughout wards. The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen.
In two successive investigations on nosocomial infections in our hospital, wa have found that asymptomatic bacteriuria is closely related to age (over 50 years) and to treatment with acetylcholine antagonistic activity. We therefore searched for the presence and expression of genes coding for the virulence factors usually present in uropathogenic E. coli in our strains, in strains isolated during asymptomatic bacteriura related to neurologic bladder, and in strains isolated during symptomatic bacteriura. We found that strains from neurologic bladders rarely carried one or two virulence factors while 50% of our strains isolated from asymptomatic bacteriuria carriea at least 3 virulence factors commonly found in strains isolated from symptomatic urinary tract infection. Consequently, it appears important to look for urinary tract infection in patients (over 50 years of age) treated with such drugs, and to look for virulence factors in case of asymptomatic bacteriura. If the stains carry no virulence factors, no antibiotic treatment shoud be instituted but the patients should be invited to drink more water than usual in order to promote elimination of the strains in the urine. Inversely, if the strains carry virulence factors, an adpted antibiotic treatment should be started.