Detection and epidemiology of carbapenemase producing Enterobacteriaceae in the Netherlands in 2013-2014.

Laboratory detection of carbapenemase-producing Enterobacteriaceae (CPE) is complicated. Screening with MIC values below clinical breakpoints followed by genotypic confirmation is recommended. We evaluated the application of recommended CPE screening and confirmation methods and provide an overview of CPE epidemiology in E. coli and K. pneumoniae in the Netherlands. Data on E. coli and K. pneumoniae isolates with elevated meropenem (>0.25 mg/L) and/or imipenem (>1 mg/L) MIC values in 2013-2014 were selected from the Infectious Disease Surveillance Information System for Antibiotic Resistance. Laboratories were requested to provide additional results of any confirmatory testing performed. Confirmation of elevated carbapenem MIC values using gradient testing was performed in 59.8 % of eligible isolates. Confirmatory testing showed elevated MIC values in 8 % of E. coli and 32 % of K. pneumoniae isolates. The overall proportion of confirmed non-susceptible E. coli and K. pneumoniae was 0.01 % and 0.16 %, respectively. Genotypic confirmation was performed in 61.0 % of isolates with confirmed elevated carbapenem MIC values. A carbapenemase gene was identified in 47 % of E. coli and 65 % of K. pneumoniae isolates. OXA-48, NDM and KPC were the most frequently found carbapenemase genes. The majority (62 %) of CPE isolates was detected through targeted screening. CPE are a rare finding in the Netherlands. Adherence to the national guideline is suboptimal and differs between laboratories, implying a risk of inadequate CPE detection. Since accurate identification of CPE is the first step in prevention of CPE spread, successful implementation of guidelines for testing and reporting of CPE is essential.

Gram-positive cocci in Dutch ICUs with and without selective decontamination of the oropharyngeal and digestive tract: a retrospective database analysis.

OBJECTIVES: The objective of this study was to determine time trends in the rate of Gram-positive cocci in 42 Dutch ICUs that continuously used or did not use selective oropharyngeal decontamination (SOD) or selective decontamination of the digestive tract (SDD) and ICUs that introduced SOD/SDD. METHODS: The Dutch Surveillance System on Antibiotic Resistance was used to determine monthly rates of Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium isolates, including resistant phenotypes, in blood and respiratory tract specimens from 2008 to 2013. Per patient, the last isolate per species per month was selected, and cumulative rates per 100 beds per month were determined. Time trends were analysed by multilevel Poisson regression. RESULTS: Eighteen ICUs used SOD/SDD (1296 months), 13 did not use SOD/SDD (936 months) and 11 introduced SOD/SDD (373 months before and 419 months after introduction). There was no significant increase in the rate of Gram-positive cocci in ICUs that used SOD/SDD. Introduction of SOD/SDD was associated with increased rates of S. aureus (ß = 0.018, 95% CI 0.006-0.030) and E. faecalis isolates (ß = 0.028, 95% CI 0.006-0.051) in respiratory tract specimens. Numbers of resistant phenotypes remained low, and an observed increase in E. faecium isolates (ß = 0.033, 95% CI 0.012-0.054), 97% of which were resistant to ampicillin, in the absence of SOD/SDD disappeared after the introduction of SOD/SDD. CONCLUSIONS: In ICUs with a low endemicity of resistance, introduction of SOD/SDD was associated with increased rates of S. aureus and E. faecalis isolates, but not with resistant phenotypes. Continuous 5 year use of SOD/SDD was not associated with increased isolation of Gram-positive cocci.