Trends of methicillin-resistant Staphylococcus aureus (MRSA) and Enterobacteriaceae-producing extended-spectrum β-lactamase (ESBLE) in eastern France: a three-year multi-centre incidence study

Hospital cross-transmission of extended-spectrum β-lactamase producing Escherichia coli and Klebsiella pneumoniae

OBJECTIVES

We had for objective to measure the incidence and the clonal diversity of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBL) in order to assess the role of patient stay in amplification of the phenomenon, in our teaching hospital.

MATERIAL AND METHODS

We measured the quarterly incidence rates of E. coli and K. pneumoniae producing or not producing ESBL in clinical samples between 1999 and 2010. The incidence of ESBL-producing isolates was season-adjusted. We determined the pulsotype of and identified the ESBL in all non-redundant strains isolated between 2009 and 2010.

RESULTS

The incidence for 1000 hospitalization days increased from 0.00 to 0.44 for ESBL-producing E. coli, from 0.012 to 0.24 for ESBL-producing K. pneumoniae, from 1999 to 2010. Fifty-three different clones of E. coli were identified among the 61 genotyped isolates. The 28 K. pneumoniae isolates genotyped clustered into 11 different clones, among which one major epidemic clone that included 18 isolates. Respectively 66 and 75% of E. coli and K. pneumoniae isolates produced a CTX-M group 1 ESBL.

CONCLUSION

The hospital seems to play a different role in the amplification of ESBL according to the producing species (K. pneumoniae or E. coli). ESBL-producing E. coli seem to have a limited cross-transmission within the hospital and seem to be added to non-producers. Conversely, ESBL-producing K. pneumoniae seem to be cross-transmitted within the hospital and to replace non-producers.

Clinical profiles of patients colonized or infected with extended-spectrum beta-lactamase producing Enterobacteriaceae isolates: a 20 month retrospective study at a Belgian University Hospital

Background

Description of the clinical pictures of patients colonized or infected by ESBL-producing Enterobacteriaceae isolates and admitted to hospital are rather scarce in Europe. However, a better delineation of the clinical patterns associated with the carriage of ESBL-producing isolates may allow healthcare providers to identify more rapidly at risk patients. This matter is of particular concern because of the growing proportion of ESBL-producing Enterobacteriaceae species isolates worldwide.

Methods

We undertook a descriptive analysis of 114 consecutive patients in whom ESBL-producing Enterobacteriaceae isolates were collected from clinical specimens over a 20-month period. Clinical data were obtained through retrospective analysis of medical record charts. Microbiological cultures were carried out by standard laboratory methods.

Results

The proportion of ESBL-producing Enterobacteriaceae strains after exclusion of duplicate isolates was 4.5% and the incidence rate was 4.3 cases/1000 patients admitted. Healthcare-associated acquisition was important (n = 104) while community-acquisition was less frequently found (n = 10). Among the former group, two-thirds of the patients were aged over 65 years and 24% of these were living in nursing homes. Sixty-eight (65%) of the patients with healthcare-associated ESBL, were considered clinically infected. In this group, the number and severity of co-morbidities was high, particularly including diabetes mellitus and chronic renal insufficiency. Other known risk factors for ESBL colonization or infection such as prior antibiotic exposure, urinary catheter or previous hospitalisation were also often found. The four main diagnostic categories were: urinary tract infections, lower respiratory tract infections, septicaemia and intra-abdominal infections. For hospitalized patients, the median hospital length of stay was 23 days and the average mortality rate during hospitalization was 13% (Confidence Interval 95%: 7-19). Escherichia coli, by far, accounted as the most common ESBL-producing Enterobacteriaceae species (77/114; [68%]) while CTX-M-1 group was by far the most prevalent ESBL enzyme (n = 56).

Conclusion

In this retrospective study, the clinical profiles of patients carrying healthcare-associated ESBL-producing Enterobacteriacae is characterized by a high prevalence rate of several major co-morbidities and potential known risk factors. Both, the length of hospital stay and overall hospital mortality rates were particularly high. A prospective case-control matched study should be designed and performed in order to control for possible inclusion bias.

Risk factors for multidrug-resistant bacteria in patients with post-operative peritonitis requiring intensive care

OBJECTIVES

This prospective non-interventional study investigated the risk factors for multidrug-resistant bacteria (MDRB) in patients with post-operative peritonitis (POP), to provide guidance for empirical antimicrobial therapy.

METHODS

All consecutive patients, >15 years old, admitted to a surgical intensive care unit (ICU) between September 2006 and January 2009 for a first episode of POP were included. Antibiotic susceptibilities of microorganisms recovered from blood cultures and peritoneal fluid were determined by disc diffusion. Amoxicillin/clavulanic acid, ticarcillin/clavulanic acid, piperacillin/tazobactam, cefotaxime, ceftazidime, cefepime, imipenem, gentamicin, amikacin and ciprofloxacin were tested against Gram-negative bacteria, and oxacillin, amoxicillin, vancomycin, gentamicin and erythromycin were tested against aerobic Gram-positive bacteria. Results were reported as susceptible or resistant.

RESULTS

MDRB were isolated from 20/115 (17%) patients. In univariate analysis, use of antimicrobial therapy during the 3 months prior to hospitalization and a long duration between hospital admission or first operation and relaparotomy were significantly associated with MDRB recovery. In multivariate analysis, only antimicrobial treatment in the 3 months preceding hospitalization and duration between first operation and relaparotomy were independent risk factors for MDRB [odds ratio (OR) = 5.80, 95% confidence interval (95% CI) = 1.99-16.91 and OR = 1.10, 95% CI = 1.02-1.19, respectively]. No MDRB were found when the delay between the first operation and relaparotomy was <5 days. POP severity, non-surgical and surgical complications, hospital and ICU length of stay, and mortality were similar in patients with and without MDRB.

CONCLUSIONS

Our results suggest that broad-spectrum antibiotics should be used in ICU patients with POP who have received antimicrobial therapy in the 3 months prior to hospitalization, or with >5 days between the first operation and relaparotomy.