A novel large plasmid carrying multiple beta-lactam resistance genes isolated from a Klebsiella pneumoniae strain

Klebsiella pneumoniae: Prevalence, Reservoirs, Antimicrobial Resistance, Pathogenicity, and Infection: A Hitherto Unrecognized Zoonotic Bacterium

Klebsiella pneumoniae is considered an opportunistic pathogen, constituting an ongoing health concern for immunocompromised patients, the elderly, and neonates. Reports on the isolation of K. pneumoniae from other sources are increasing, many of which express multidrug-resistant (MDR) phenotypes. Three phylogroups were identified based on nucleotide differences. Niche environments, including plants, animals, and humans appear to be colonized by different phylogroups, among which KpI (K. pneumoniae) is commonly associated with human infection. Infections with K. pneumoniae can be transmitted through contaminated food or water and can be associated with community-acquired infections or between persons and animals involved in hospital-acquired infections. Increasing reports are describing detections along the food chain, suggesting the possibility exists that this could be a hitherto unexplored reservoir for this opportunistic bacterial pathogen. Expression of MDR phenotypes elaborated by these bacteria is due to the nature of various plasmids carrying antimicrobial resistance (AMR)-encoding genes, and is a challenge to animal, environmental, and human health alike. Raman spectroscopy has the potential to provide for the rapid identification and screening of antimicrobial susceptibility of Klebsiella isolates. Moreover, hypervirulent isolates linked with extraintestinal infections express phenotypes that may support their niche adaptation. In this review, the prevalence, reservoirs, AMR, Raman spectroscopy detection, and pathogenicity of K. pneumoniae are summarized and various extraintestinal infection pathways are further narrated to extend our understanding of its adaptation and survival ability in reservoirs, and associated disease risks.

Transfer of carbapenem-resistant plasmid from Klebsiella pneumoniae ST258 to Escherichia coli in patient

Klebsiella pneumoniae carbapenemase (KPC) 3-producing Escherichia coli was isolated from a carrier of KPC-3-producing K. pneumoniae. The KPC-3 plasmid was identical in isolates of both species. The patient's gut flora contained a carbapenem-susceptible E. coli strain isogenic with the KPC-3-producing isolate, which suggests horizontal interspecies plasmid transfer.

Detection of aac(6')-Ib-cr in KPC-producing Klebsiella pneumoniae isolates from Tel Aviv, Israel

OBJECTIVES

We aimed to evaluate the occurrence and characteristics of plasmid-mediated quinolone resistance (PMQR) genes in KPC-producing (KPC-P) Klebsiella pneumoniae (Kpn) isolates in Tel Aviv Medical Center, Israel.

METHODS

Forty-seven KPC-P Kpn isolates were studied. Antibiotic susceptibilities were determined by Vitek 2, Etest or agar dilution. Beta-lactamases and PMQR determinants were detected by PCR. For plasmid characterization, transformation, transconjugation, restriction mapping and Southern blot analysis were performed.

RESULTS

Six out of 47 (13%) KPC-P isolates carried aac(6')-Ib-cr. Acquisition of aac(6')-Ib-cr-encoding plasmids increased the MIC of ciprofloxacin by 2-fold. In five of six KPC-P isolates, aac(6')-Ib-cr and bla(KPC-2) were encoded on the same plasmid.

CONCLUSIONS

The most prevalent PMQR gene in the studied KPC-P K. pneumoniae isolates is aac(6')-Ib-cr. The co-existence of PMQR genes with KPC on the same plasmid poses a serious epidemiological, clinical and public-health threat.

Plasmid-mediated qnrB2 and carbapenemase gene bla(KPC-2) carried on the same plasmid in carbapenem-resistant ciprofloxacin-susceptible Enterobacter cloacae isolates

Fourteen out of 16 carbapenem-resistant quinolone-susceptible Enterobacter cloacae isolates were found to carry qnrB2 and bla(KPC-2) genes encoded on the same plasmid. One isolate also carried the aac(6')-Ib-cr gene. Coexistence of quinolone resistance determinants and bla(KPC-2) on the same plasmid in quinolone-susceptible E. cloacae isolates may have important clinical implications.