Didier Lepelletier

Surgical-Site Infection After Cardiac Surgery: Incidence, Microbiology, and risk Factors

OBJECTIVE To identify risk factors associated with surgical-site infection according to the depth of infection, the cardiac procedure, and the National Nosocomial Infections Surveillance System risk index. DESIGN Prospective survey conducted during a 12-month period. SETTING A 48-bed cardiac surgical department in a teaching hospital. PATIENTS Patients admitted for cardiac surgery between February 2002 and January 2003. RESULTS Surgical-site infections were diagnosed in 3% of the patients (38 of 1,268). Of the 38 surgical-site infections, 20 were superficial incisional infections and 18 were mediastinitis for incidence rates of 1.6% and 1.4%, respectively. Cultures were positive in 28 cases and the most commonly isolated pathogen was Staphylococcus. A National Nosocomial Infections Surveillance System risk index score of 2 or greater was associated with a risk of surgical-site infection (relative risk, 2.4; P < .004). Heart transplantation, mechanical circulatory assistance, coronary artery bypass graft with the use of internal mammary artery, and reoperation for cardiac tamponade or pericard effusion were independent risk factors associated with surgical-site infection. CONCLUSIONS Data surveillance using incidence rates stratified by cardiac procedure and type of infection is relevant to improving infection control efforts. Risk factors in patients who developed superficial infection were different from those in patients who developed mediastinitis. Coronary artery bypass graft using internal mammary artery was associated with a high risk of surgical-site infection, and independent factors such as reoperation for cardiac tamponade or pericard effusion increased the risk of infection.

Escherichia coli: Epidemiology and Analysis of Risk Factors for Infections Caused by Resistant Strains

This study analyzes the epidemiology of hospital and community-acquired infections caused by Escherichia coli. The antimicrobial resistance pattern was used to characterize the isolates, and a prospective observational study was performed to assess the relationship between antimicrobial use and bacterial resistance. The study was conducted during a 3-month period in a 1,200-bed tertiary care hospital in Nantes, France. An E. coli infection was diagnosed in 3.8% of the patients (507 of 13,384) admitted to the hospital between 1 January and 31 March 1996. Of the 507 isolates, 205 (40.4%) were resistant to at least one antimicrobial; 40% were resistant to amoxicillin, 30% to amoxicillin/clavulanate, 38% to ticarcillin, and 16% to trimethoprim-sulfamethoxazole, while resistance to other antimicrobials was low. Prior receipt of antimicrobial and/or immunosuppressive therapy was significantly associated with infection caused by a resistant organism.

Eradication of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit: which measures for which success?

BACKGROUND Various strategies for controlling methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in neonatal intensive care units (NICUs) have been tried, with varying levels of success. We report a MRSA outbreak occurring between April 2004 and August 2007 in a 24-bed NICU in a large university hospital. We describe the difficulties involved in implementing measures to control the MRSA outbreak and the possible contribution of each measure. METHODS Cases were defined as neonates with MRSA obtained from either clinical cultures or surveillance cultures (from the anterior nares). Systematic screening of neonates for colonization was performed only between February and December 2005. Successive control strategies included barrier precaution and isolation in individual rooms, mupirocine ointment for neonates and health care workers, cohort isolation, hand hygiene observation, and staff training. RESULTS During the routine surveillance culture period (February to December 2005; 48 weeks), 46 neonates were found to be positive for MRSA and were treated with mupirocin. After December 2005, the outbreak was controlled, but the ongoing spread was not eradicated; 9 sporadic MRSA cases were detected by clinical culture up to August 2007. CONCLUSION The widespread use of mupirocine in staff and patients did not control the outbreak and is not recommended. The later control appeared to coincide with increased hand hygiene audits and training for staff, along with appropriate cohort isolation of neonates and cohort nursing.

Risk of Highly Resistant Bacteria Importation from Repatriates and Travelers Hospitalized in Foreign Countries: About the French Recommendations to Limit Their Spread

The rapid development of transport and communication, environmental exchanges, and migration of populations creates opportunities for the spread of infectious diseases. The emergence and spread of pathogenic and epidemic pathogens is a major emerging phenomenon of the past 30 years. Some species of bacteria have become resistant to multiple antibiotics and, sometimes, to all antibiotics available: multidrug‐resistant bacteria (MDR), extensively drug‐resistant bacteria (XDR), or pan drug‐resistant bacteria (PDR). 1–3 These terminologies have drawn attention to the evolution of multidrug resistance and the potential difficulties in treating bacterial infections now and in the future. 4 The very high levels of resistance that are currently observed result from massive exposure to antibiotics, to which humans and animals have been subjected over the past 50 years. 5 Resistance to antibiotics concerns not only pathogens but also, and probably even more importantly, the commensally bacteria colonizing individuals (humans and animals). These are less easily detected because the carriage is asymptomatic. More than 80 million foreign visitors travel in France each year. In the same period, 19.4 million French peoples travel to foreign countries, more often in Europe. 6 In addition, 1.4 million French peoples live in foreign countries (i.e., 48% Europe, 20% America, 15% Africa, 8.5% in Asia‐Oceania, and 6.6% in the Near and Middle East). 7 The repatriation of French patients from foreign hospitals, but also health care provided to foreigners traveling in France, whatever their nationality, then expose the French population to highly resistant bacteria acquired in high resistance prevalent areas. The risk of the emergence and spread of highly resistant bacteria from migration has been recently evaluated in France because sporadic or limited epidemic situations have occurred in the recent past with pathogens such as Clostridium difficile ribotype 027, 8,9 carbapenemase‐producing Enterobacteriaceae (CPE), 10–12 vancomycin‐resistant Enterococcus (VRE), 13,14 or multidrug‐resistant Acinetobacter … Corresponding Author: Didier Lepelletier, MD, PhD, Unite de Gestion du Risque Infectieux ‐ Service de Bacteriologie‐Hygiene, Centre Hospitalier Universitaire de Nantes, F‐44093 Nantes Cedex 01, France. E‐mail: didier.lepelletier{at}chu-nantes.fr

Retrospective analysis of the risk factors and pathogens associated with early-onset ventilator-associated pneumonia in surgical-ICU head-trauma patients.

Background Early-onset ventilator associated pneumonia (EOVAP) are frequent in head-trauma patients, but specific risk factors are poorly studied in this population. Methods We conducted a retrospective cohort study in a surgical intensive care unit. Consecutive severe head-trauma patients admitted from January 2000 to December 2002 were studied. Microorganisms, and risks factors for EOVAP were analyzed. Results During the 3-year period, 161 patients were studied; 21.1% of them developed an EOVAP. On univariate analysis 6 variables were associated with EOVAP: early enteral feeding, barbiturate use, immunosuppression, mean Simplified Acute Physiology Score 2, acute respiratory distress syndrome, and initial neurosurgery procedures. On multivariate analysis, enteral feeding >2000 Kcal before day 5 [odds ratio (OR): 0.33, 95% confidence interval (CI): 0.21-0.85] and initial neurosurgical procedure (OR: 0.36, 95% CI: 0.15-0.89) remained protective factors for EOVAP, whereas immunosuppression (OR: 7.15, 95% CI: 1.66-30.73) and barbiturate use (OR: 2.68, 95% CI: 1.06-6.80) remained risk factors for EOVAP. EOVAP was also significantly associated with a longer duration of mechanical ventilation (14.0 vs. 11.0 d, P=0.024), and a longer sedation duration (8.3 vs. 5.8 d P=0.005). Methicillin-susceptible Staphylococcus aureus was the most common pathogen involved in EOVAP (46%). Conclusions We demonstrate for the first time that early enteral feeding is a protective factor for EOVAP, and this result could have clinical implications for the prevention of EOVAP after traumatic brain injury. This study also confirms that barbiturate use is an important risk factor of EOVAP whereas Methicillin-susceptible S. aureus was found to be the main pathogen involved in EOVAP.

Orthopaedic-implant infections by Escherichia coli: molecular and phenotypic analysis of the causative strains.

OBJECTIVES Little is known about Escherichia coli Orthopaedic Implant Infections (OII) pathogenesis. Thus, we compared 30 clinical strains isolated in this context with 30 clinical strains of faecal origin, in order to identify phenotypic and genetic features related to E. coli OII. METHODS Phylogenetic analysis and detection of 19 virulence genes were performed by PCR. Ability to form biofilm was studied using the crystal violet reference method and the innovative BioFilm Ring Test(®). RESULTS Most of the OII isolates (56.7%) belonged to the virulence-associated phylogenetic group B2, but did not present a specific set of virulence factors. S fimbriae was the only adhesin significantly associated with OII isolates. Isolates varied greatly in their ability to form biofilm but OII isolates did not produce significantly more biofilm in vitro than isolates of faecal origin, whatever the method used. CONCLUSIONS Neither a specific pathogenic signature nor an increased ability to form biofilm in vitro was detected in E. coli strains isolated from OII. Nevertheless, genetic properties of these isolates could provide a clue to their origin. Hence, we found that virulence factors of uropathogenic strains and urological disorders were frequently detected among our OII cohort.

Electronic sensors for assessing interactions between healthcare workers and patients under airborne precautions.

Background Direct observation has been widely used to assess interactions between healthcare workers (HCWs) and patients but is time-consuming and feasible only over short periods. We used a Radio Frequency Identification Device (RFID) system to automatically measure HCW-patient interactions. Methods We equipped 50 patient rooms with fixed sensors and 111 HCW volunteers with mobile sensors in two clinical wards of two hospitals. For 3 months, we recorded all interactions between HCWs and 54 patients under airborne precautions for suspected (n = 40) or confirmed (n = 14) tuberculosis. Number and duration of HCW entries into patient rooms were collected daily. Concomitantly, we directly observed room entries and interviewed HCWs to evaluate their self-perception of the number and duration of contacts with tuberculosis patients. Results After signal reconstruction, 5490 interactions were recorded between 82 HCWs and 54 tuberculosis patients during 404 days of airborne isolation. Median (interquartile range) interaction duration was 2.1 (0.8–4.4) min overall, 2.3 (0.8–5.0) in the mornings, 1.8 (0.8–3.7) in the afternoons, and 2.0 (0.7–4.3) at night (P<10−4). Number of interactions/day/HCW was 3.0 (1.0–6.0) and total daily duration was 7.6 (2.4–22.5) min. Durations estimated from 28 direct observations and 26 interviews were not significantly different from those recorded by the network. Conclusions The RFID was well accepted by HCWs. This original technique holds promise for accurately and continuously measuring interactions between HCWs and patients, as a less resource-consuming substitute for direct observation. The results could be used to model the transmission of significant pathogens. HCW perceptions of interactions with patients accurately reflected reality.

Nosocomial outbreak of carbapenem-resistant Enterobacter cloacae highlighting the interspecies transferability of the blaOXA-48 gene in the gut flora

Sir, The emergence and dissemination of carbapenemases (KPC, VIM, IMP, NDM or OXA-48) among Enterobacteriaceae is a serious concern worldwide as it raises the problem of the lack of therapeutic options linked to frequent co-resistance. In November 2010, French guidelines were published to control the spread of carbapenemase-producing Enterobacteriaceae from patients repatriated and travellers hospitalized in French hospitals. However, we report the in vivo interspecies transferability of the OXA-48 carbapenemase by the investigation and management of a nosocomial outbreak in France. In April 2011, an elderly patient (Patient A) was transferred from Agadir (Morocco) to the internal medicine unit at Nantes University Hospital, France, for the treatment of a hip prosthetic joint infection. Upon admission, contact precautions were immediately adopted. A rectal swab inoculated on CHROMagarTM KPC medium (CHROMagar, Paris, France) revealed the gastrointestinal carriage of Enterobacter cloacae and Escherichia coli, both resistant to ertapenem and positive for blaOXA-48 by PCR. Therefore, a weekly colonization surveillance was performed on all patients hospitalized in the unit, and led to the discovery of OXA-48-producing E. cloacae in 3/54 patients (B, C and D) without recent history of travel. Furthermore, rectal swabs performed for Patients A and B found two OXA-48-producing Klebsiella pneumoniae isolates (Figure 1). The time between admission to the unit and the first positive culture varied between 3 and 16 days for the three secondary patients. However, Patient D, with a first negative screening, was transferred to the intensive care unit, and was detected as a carrier 3 days after re-admission to the internal medicine unit. We cannot exclude the possibility that this patient was colonized during the first stay in the internal medicine unit. OXA-48-producing E. cloacae isolates were detected intermittently in this patient (Figure 1). None of the four carriers developed infection. Active surveillance was continued until the last colonized patient was discharged. All isolates were resistant to ertapenem (range of MICs, 2 to ≥32 mg/L) and exhibited intermediate susceptibility or susceptibility to imipenem (range of MICs, 0.38–6 mg/L) and meropenem (range of MICs, 0.25–0.5 mg/L) according to the EUCAST guidelines 2011. Molecular testing showed that all E. cloacae isolates harboured the blaCTX-M-15 ESBL gene, while both E. coli and K. pneumoniae isolates were susceptible to third-generation cephalosporins and did not present any of the additional b-lactamases searched for (blaTEM, blaSHV apart from blaSHV-1, and blaCTX-M). The E. coli and K. pneumoniae isolates did not yield subcultures when plated on a CHROMagarTM ESBL medium (CHROMagar, Paris, France). Although other authors reported poor growth of E. coli strains, and underlined difficulties in differentiating colonies of E. cloacae and K. pneumoniae, in our experience the CHROMagarTM KPC medium was useful. The OXA-48 producing E. coli isolate from Patient A yielded a few small pink colonies, whereas the OXA-48producing K. pneumoniae isolate showed better growth, with large navy blue colonies easily distinguishable from the steel blue colonies of the OXA-48-producing E. cloacae isolate. All E. cloacae isolates showed indistinguishable PFGE patterns. According to PFGE and multilocus sequence typing (MLST; http://www.pasteur.fr/recherche/genopole/PF8/mlst/ Kpneumoniae.html) analyses, K. pneumoniae isolates were not clonally related [one new sequence type (ST) and one ST152]. The E. coli isolate belonged to ST38 (MLST, http://mlst.ucc.ie/ mlst/dbs/Ecoli). The blaOXA-48 gene was transferred by conjugation 4 to a rifampicin-resistant E. coli J53-2 from the E. cloacae, K. pneumoniae and E. coli isolates, while transfer of the blaCTX-M-15 gene from the E. cloacae isolates failed. Extraction of plasmids revealed that E. cloacae isolates carried two plasmids (60 and 165 kb), whereas E. coli, both K. pneumoniae isolates and all blaOXA-48-positive transconjugants carried a single plasmid that co-migrated with the 60 kb plasmid of E. cloacae isolates. The blaOXA-48 gene was part of the plasmid-borne Tn1999.2 transposon, since an insertion sequence IS1999 interrupted by an IS1R was detected by PCR mapping upstream of the blaOXA-48 gene. 2 This is the first report of a patient colonized with three enterobacterial isolates (E. cloacae, E. coli and K. pneumoniae) harbouring the blaOXA-48 gene. The emergence of this gene has been linked to the spread of a peculiar Tn1999-type transposon, but also to the dissemination of specific clones. Poirel et al. indicated that the same strain of OXA-48-producing E. coli, belonging to ST38, had been imported from Egypt and Turkey into France. In our study, Patient A carried an ST38-type E. coli, but the strain did not display an ESBL phenotype, as previously described. The discovery of the OXA-48 carbapenemase in several enterobacteria of the index case’s gastrointestinal flora rather suggested the possibility of an in vivo transfer of the OXA-48-encoding plasmid. This was confirmed by the isolation of another OXA-48-producing K. pneumoniae isolate in Patient B. In the gut, selection of resistant strains has been associated with a biological fitness cost and often reflects the impact of antimicrobial selection pressure. Previous exposure to fluoroquinolones or antipseudomonal penicillins has been described as a risk factor for acquisition of Research letters

Surveillance and control of methicillin-resistant Staphylococcus aureus infections in French hospitals.

OBJECTIVE To assess the way French hospitals conduct surveillance for, and control infections caused by, methicillin-resistant Staphylococcus aureus (MRSA), and to evaluate the incidence of these infections. DESIGN Retrospective analysis of sample surveillance data. SETTING Representative sample of French hospitals. PARTICIPANTS Representative sample of 38 French public hospitals. METHODS Hospitals were selected randomly in 1996, taking into account their location and number of beds. Administrative data, surveillance denominators used, antimicrobial resistance rates, and infection control practices were analyzed for the period 1990 to 1995. The same 38 centers were contacted 3 years later, in 1998, to reassess their surveillance and control activities. RESULTS French hospitals were slow to implement MRSA surveillance programs; only 5% had such programs in 1990, when the median incidence per admission (0.37%) and per patient-days (0.04%) of MRSA infections was already high. Despite the implementation of surveillance programs in 66% of French hospitals in 1995 and 87% in 1998, the MRSA infection rates remained stable from 1990 to 1995 and increased from 1995 to 1998. The proportion of French hospitals having a policy for the transfer of MRSA-infected patients to other hospitals increased from 47% in 1995 to 61% in 1998, whereas screening for MRSA colonization (42%-53%) and isolation for colonized or infected patients (87%-89%) remained stable. CONCLUSIONS This first national survey showed that French hospitals probably were not optimally prepared to control and prevent MRSA infections, since they were slow to respond to the growing problem.

First Report of a Hip Prosthetic and Joint Infection Caused by Lactococcus garvieae in a Woman Fishmonger

ABSTRACT We describe the first case of hip prosthetic infection due to Lactococcus garvieae. The patient, a 71-year-old woman fishmonger, developed a hip infection 7 years after total hip arthroplasty. The origin of infection was possibly due to the manipulation or intake of seafood or fish contaminated with Lactococcus garvieae.