Carbapenem-resistant Gram-negativesSunday, April 11, 2010, 13:30 - 14:30
The first carbapenemase-producing Klebsiella pneumoniae strains in the Netherlands are associated with international travelJ.W. Cohen Stuart, G. Voets, D. Versteeg, J. Scharringa, M. Tersmette, E. Roelofsen, A.C. Fluit, M. Leverstein-van Hall* (Utrecht, Nieuwegein, Groningen, NL)
Objectives: Carbapenems are often used as a last resort for treating serious infections caused by multidrug-resistant gram-negatives (MDR-GN). Carbapenemase-producing Enterobacteriaceae are emerging worldwide, but, until now, none have been reported in The Netherlands. In this study, we determined whether the elevated carbapenem MICs of three K. pneumoniae isolates (KPN) isolated in 3 different Dutch hospitals were due to carbapenemase production. Isolate KPN-1 en KPN-2 were isolated from 2 patients that had recently returned from a holiday trip in India. During their trip they had not visited any medical care facility but had taken unspecified tablets against enteritis. The KPN-3 was from a patient transferred from a Greek hospital to which he had been admitted during his holiday.
Methods: MICs were determined using broth micro-dilution (MBD), VITEK and Etests (BioMérieux, Paris, France). For phenotypic confirmation a modified Hodge test, imipenem-EDTA and imipenem-boronic acid (BA) synergy tests were performed. Genotypic confirmation was done by PCR and sequencing.
Results: Table 2 shows the results of the susceptibility tests for 3 carbapenems and the confirmation tests. KPN-1 and 2 were only susceptible to colistin, tigecycline and chloramphenicol. KPN-1 contained a New-Delhi metallo-carbapenemase gene (NDM-1), a CTX-M-1 group ESBL gene, and two AmpC genes (CMY-6, DHA-1) while in KPN-2 only NDM-1was detected. These findings are in line with previous reports on NDM-1 positive isolates obtained from patients with prior medical treatment in India.
KPN-3 was only susceptible to gentamicin, tobramycin, amikacin, colistin, and tigecycline. In this strain a KPC-2 gene and a SHV-12 ESBL gene were identified, consistent with the hyperepidemic clone described in Greek hospitals.
Conclusion: The first carbapenemase-producing KPN in The Netherlands were travel-associated. Patients undergoing medical treatment in countries with high prevalence of MDR-GN have an increased risk of acquiring these micro-organisms. In low endemic countries, the in-hospital spread of MDR-GN may be prevented by identifying those patients treated in high risk countries, and to screen them at admission. However, when travelers may also acquire acquire carbapenemase producing isolates without medical treatment, this control strategy may fail, resulting in an uncontrollable introduction and spread of carbapenemases in low endemic countries such as The Netherlands.