Carbapenemase-producing Klebsiella pneumoniae (CRKP) are increasingly reported worldwide being necessary the local epidemiological monitoring. Our aim was to characterize the hypermucoviscous CRKP isolates collected in our hospital during a 6 months period. Carriage of the carbapenemase genes ( bla KPC , bla NDM , bla VIM and bla OXA-48 ), extended spectrum β-lactamases ( bla SHV-2 , bla CTX-M ) and the virulence genes ( mag A, k2A, rmp A, wab G, uge , all S, ent B, ycf M, kpn , wca G, fim H, mrk D, iut A, iro N, hly and cnf -1) were determined by multiplex-PCR. Genetic relationship among the isolates was performed by PFGE and MLST. A total of 35 isolates were recovered, being the urinary and respiratory tract the most common infection sites (34.2%). The bla KPC-2 gene was present in all the isolates, coexisting with bla CTX-M-2 (45.7%), bla SHV-2 (28.6%), and bla CTX-M-2 / bla SHV-2 (14.3%). The capsular serotype K2 corresponded with 68.6% of the isolates. Virulence factors frequency were variable [adhesins (97.1%), siderophores (94.3%) and phagocytosis resistance ( wab G 48.5%, uge 80% and ycf M 57.1%)]. A total of 10 STs were identified although 40% of them clustered on ST25-CC65, and 17% to ST17. The incidence of KPC-2-producing K. pneumoniae reported by the hospital was 0.290 per 1000 admissions. In summary we described an epidemic scenario of multidrug resistant hypermucoviscous KPC-2 producing ST25 K. pneumoniae in our institution.

IntroductionKlebsiella aerogenes is a nosocomial pathogen associated with drug resistance and healthcare-associated infections. We pursued this study to investigate an outbreak of clinical carbapenem-resistant K. aerogenes(CRKA) in an argentinian tertiary hospital which persisted for 4 months despite aggressive infection control measures. The primary goals aimed to evaluate the molecular characteristics and the clonal relationships among the CRKA isolates.MethodsWe characterized CRKA isolates by multiplex PCR and PFGE. The information was integrated with clinical and epidemiologic data.ResultsThe 14 CRKA strains were disseminated in an adult intensive care unit (50%) and five different wards. In patients who received antimicrobial treatment, 8 staggered to directed treatment, mainly with amikacin(6/8) and/or carbapenemes(5/8). The overall mortality was 42.8%, and the attributed mortality to CRKA infection was 21.4%, strains showed high rates of resistance to most of the antimicrobials without resistance to Amikacin and Tigecycline, and carried the blaKPC-2, blaSHV-2 and blaCTXM-15 genes. The PFGE indicated 2 distinct groups; 12/14 CRKA isolatesassociated with the dominant subgroup A and likely to be primarily responsible for the first isolation and subsequent dissemination in the hospital.ConclusionThe outbreak characteristics data showed prolonged hospitalization and previous use of broad-spectrum antibiotics as potential risk factors for the acquisition of CRKA.

Introduction. Klebsiella aerogenes is a nosocomial pathogen associated with drug resistance and healthcare-associated infections. Gap Statement. K. aerogenes is associated with hospital-acquired infections with the ability to acquire mechanisms of resistance to reserve antimicrobials; its clinical behaviour has been poorly documented. Objective. We proposed to investigate an outbreak of carbapenem-resistant K. aerogenes in a hospital that persisted for 4 months. Methods. The primary aim was to evaluate the molecular characteristics and the clonal relationships among the isolates. We characterized isolates by polymerase chain reaction (PCR) and pulsed-field gel electrophoresis (PFGE). The information was integrated with clinical and epidemiological data. Results. Fourteen strains were disseminated in an intensive care unit and different wards at the hospital. The overall mortality was 42.8 %, and mortality attributed to infection was 21.4 %; strains showed high rates of resistance to most of the antimicrobials tested and carried bla KPC-2, bla SHV-2 and bla CTXM-15 genes. PFGE analysis indicated 2 PFGE groups; 12/14 isolates were associated with subgroup A and were likely to be primarily responsible for the first isolation and subsequent dissemination. The outbreak characteristics data showed prolonged hospitalization and previous use of antibiotics as potential risk factors. Conclusion. We consider that it is essential to perform phenotypic and genotypic identification of early genetic resistance mechanisms in K. aerogenes isolates, not only from infection sites but also from colonization, to prevent the spread of these multidrug-resistant (MDR) isolates.

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