A Long-Term Low-Frequency Hospital Outbreak of KPC-Producing Klebsiella pneumoniae Involving Intergenus Plasmid Diffusion and a Persisting Environmental Reservoir

Abstract

BackgroundTo study the molecular characteristics of a long-term, low frequency outbreak of bla KPC-2 in a low prevalence setting involving the hospital environment.Methodology/Principal FindingsKPC-producing bacteria were screened by selective chromogenic agar and Real-Time PCR. The presence of antibiotic resistance genes was ascribed by PCRs and subsequent sequencing, and the KPC-producing isolates were phylogenetically typed using PFGE and multi-locus sequence typing. Bla KPC-2-plasmids were identified and analysed by S1-nuclease-PFGE hybridization and PCR based replicon typing. A ∼97 kb IncFII plasmid was seen to carry bla KPC-2 in all of the clinical isolates, in one of the isolates recovered from screened patients (1/136), and in the Klebsiella pneumoniae and Enterobacter asburiae isolates recovered from the environment (sinks) in one intensive care unit. The K. pneumoniae strain ST258 was identified in 6 out of 7 patients. An intergenus spread to E. asburiae and an interspecies spread to two different K. pneumoniae clones (ST27 and ST461) of the bla KPC-2 plasmid was discovered. K. pneumoniae ST258 and genetically related E. asburiae strains were found in isolates of both human and environmental origins.Conclusions/SignificanceWe document a clonal transmission of the K. pneumoniae ST258 strain, and an intergenus plasmid diffusion of the IncFII plasmid carrying bla KPC-2 in this outbreak. A major reservoir in the patient population could not be unveiled. However, the identification of a persisting environmental reservoir of strains with molecular determinants linked to human isolates, suggests a possible role of the environment in the maintenance of this long-term outbreak.

Risk factors for KPC-producing Klebsiella pneumoniae: watch out for surgery

“…Analysis of 47 KPC-producing K. pneumoniae identified a predominant clonal type (cluster A) that comprised 33 strains (70.21 %), which were associated with ICU patients (87.87 %), urine infections (72.72 %) and a high mortality rate (78.78 %). Outbreaks of KPC-producing K. pneumoniae isolated from ICU patients have been described (Gupta et al, 2011;Tofteland et al, 2013;Yang et al, 2013) with mortality rates ranging from 52.80 to 66.70 % (Zarcotou et al, 2011;Qureshi et al, 2012). However, our results showed a higher mortality rate (78.78 %) associated with the KPC outbreak.…”

Antibiotic susceptibility profile of Klebsiella pneumoniae strains isolated from drinking and surface water

“…Klebsiella pneumoniae (K. pneumoniae) је фекална, колиформна бактерија из фамилије Enterobacteriaceae 9 , која се описује као једна од најчешћих узрочника болничких и ванбол-ничких инфекција, јер се лако преноси кон-тактом и путем заражене хране и воде 4 . Ова бактерија има велику способност стицања и преноса гена резистенције 10,11 . Изолати који се нађу у животној средини, представљају резер-воар тих гена, који се даље могу преносити и на друге бактеријске врсте.…”

“…This bacterium has large potential to acquire and to transfer genes of resistance 10,11 . Isolates that are found in the environment may represent a reservoir of these genes, which could further be transferred among the other bacterial species.…”

“…Isolates that are found in the environment may represent a reservoir of these genes, which could further be transferred among the other bacterial species. Thereby these resistant strains can appear not only in hospital settings, where they are the most common due to selective pressure caused by irrational use of antibiotics, but also in community [10][11][12][13][14] . Treatment of infections caused by resistant strains is growing public health problem, primarily due to limited choice of effective antimicrobial agents and absence of effective therapy 15 .…”

“…Изолати који се нађу у животној средини, представљају резер-воар тих гена, који се даље могу преносити и на друге бактеријске врсте. Тиме се рези-стентни сојеви могу јавити, не само у болни-чким срединама, где су најчешћи услед се-лективног притиска насталог нерационалном употребом антибиотика, већ и у општој попу-лацији [10][11][12][13][14] . Лечење инфекција узрокованих ре-зистентним сојевима је све већи јавно-здрав-water despite the purification and chlorination.…”