High clonal diversity of ESBL-producing Klebsiella pneumoniae isolates from clinical samples in a non-outbreak situation. A cohort study

Abstract

Background: Klebsiella pneumoniae has been responsible for a large number of clonal hospital outbreaks. However, some epidemiological changes have been observed since the emergence of CTX-M enzymes in K. pneumoniae. Aim: To analyse the transmission dynamics of Extended Spectrum β-Lactamase-producing Klebsiella pneumoniae (ESBL-Kp) in an acute care hospital. Methods: In 2015 a prospective cohort study was conducted. All new consecutive adult patients with ESBL-Kp isolates in all clinical samples were included. Patients with a previous known infection/colonization by ESBL-Kp and patients in high risk areas (e.g., intensive care units) were excluded. Cross-transmission was defined as the carriage of a clonally-related ESBL-Kp between newly diagnosed patients who shared the same ward for ≥48 h with another case, within a maximum time window of 4 weeks. ESBL-production was confirmed using the double-disk diffusion method and PCR. Clonal relationships were investigated by rep-PCR and multilocus sequence typing (MLST). Results: Sixty ESBL-Kp isolates from 60 patients were included and analysed. Infections and colonizations were classified as hospital-acquired (52%), healthcare-related (40%) or community-acquired (8%). High genetic diversity was detected. When epidemiological clinical data were combined with the rep-PCR, the patterns identified did not show any cases of cross-transmission. ESBL-Kp were detected in 12.5% of environmental samples. No clonal relationship could be established between environmental reservoirs and patients. The genetic mechanism detected in all strains was associated with bla CTX-M genes, and 97% were CTX-M-15. Conclusions: The dynamics of ESBL-K. pneumoniae isolated in our setting could not be explained by clonal transmission from an index patient. A polyclonal spread of ESBL-Kp was identified.

Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Clinical Samples in a Northern Portuguese Hospital: Predominance of CTX-M-15 and High Genetic Diversity

“…Considering the ESBL-producing K. pneumoniae isolates, the bla CTX-M-15 gene was the most commonly detected (66.7%) ( Table 2 ), similarly with the results obtained in different countries in clinical samples from humans [ 3 , 5 , 10 , 62 ] and pets [ 63 , 64 , 65 ]. Moreover, this gene was the most commonly detected in K. pneumoniae isolated from septicemias obtained from the same hospital of the present study (CHTMAD, Vila Real, Portugal) [ 5 ].…”

ESBL-producing Klebsiella pneumoniae in a University hospital: Molecular features, diffusion of epidemic clones and evaluation of cross-transmission

“…The clustering of CTX-M-15 producing ST405 isolates into a dominant PT was also in favor of its intra-hospital diffusion. Other groups reported hospital epidemics with ESBL-Kp ST405 producing CTX-M-15 [ 8 , 36 , 37 ]. Although this clone has been reported to produce both CTX-M-15 and a carbapenemase, all but one ST405 isolate of our collection were susceptible to carbapenems [ 38 – 43 ].…”

Molecular Typing of Klebsiella pneumoniae Clinical Isolates by Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction

“…In the same study by Parsaie Mehr et al 70% of K. pneumoniae isolates were related to urine samples and 14% were extracted from tracheal samples [5]. In a prospective cohort study by Xercavins et al to analyze the transmission dynamics of extended-spectrum β-lactamase-producing K. pneumoniae, among 60 isolates, about 47% were extracted from urine samples and only one was from respiratory tract sample [12]. e study of biofilm formation and antibiotic resistance of K. pneumoniae isolates from clinical samples by Nirwati et al revealed that among 167 isolates, gathered from a tertiary care hospital, 51.5% were extracted from respiratory specimens [13].…”