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OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo.

ABSTRACT: Carbapenem-resistance in Klebsiella pneumoniae (KP) sequence type ST258 is mediated by carbapenemases (e.g. KPC-2) and loss or modification of the major non-selective porins OmpK35 and OmpK36. However, the mechanism underpinning OmpK36-mediated resistance and consequences of these changes on pathogenicity remain unknown. By solving the crystal structure of a clinical ST258 OmpK36 variant we provide direct structural evidence of pore constriction, mediated by a di-amino acid (Gly115-Asp116) insertion into loop 3, restricting diffusion of both nutrients (e.g. lactose) and Carbapenems. In the presence of KPC-2 this results in a 16-fold increase in MIC to Meropenem. Additionally, the Gly-Asp insertion impairs bacterial growth in lactose-containing medium and confers a significant in vivo fitness cost in a murine model of ventilator-associated pneumonia. Our data suggests that the continuous selective pressure imposed by widespread Carbapenem utilisation in hospital settings drives the expansion of KP expressing Gly-Asp insertion mutants, despite an associated fitness cost.

SUBMITTER: Wong JLC

PROVIDER: S-EPMC6718652 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo.

Wong Joshua L C JLC Romano Maria M Kerry Louise E LE Kwong Hok-Sau HS Low Wen-Wen WW Brett Stephen J SJ Clements Abigail A Beis Konstantinos K Frankel Gad G

Nature communications 20190902 1

Carbapenem-resistance in Klebsiella pneumoniae (KP) sequence type ST258 is mediated by carbapenemases (e.g. KPC-2) and loss or modification of the major non-selective porins OmpK35 and OmpK36. However, the mechanism underpinning OmpK36-mediated resistance and consequences of these changes on pathogenicity remain unknown. By solving the crystal structure of a clinical ST258 OmpK36 variant we provide direct structural evidence of pore constriction, mediated by a di-amino acid (Gly115-Asp116) inser ...[more]

PMID: 31477712

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Project description:A diverse, antibiotic-naive microbiota prevents highly antibiotic-resistant microbes, including carbapenem-resistant Klebsiella pneumoniae (CR-Kp), from achieving dense colonization of the intestinal lumen. Antibiotic-mediated destruction of the microbiota leads to expansion of CR-Kp in the gut, markedly increasing the risk of bacteremia in vulnerable patients. While preventing dense colonization represents a rational approach to reduce intra- and interpatient dissemination of CR-Kp, little is known about pathogen-associated factors that enable dense growth and persistence in the intestinal lumen. To identify genetic factors essential for dense colonization of the gut by CR-Kp, we constructed a highly saturated transposon mutant library with >150,000 unique mutations in an ST258 strain of CR-Kp and screened for in vitro growth and in vivo intestinal colonization in antibiotic-treated mice. Stochastic and partially reversible fluctuations in the representation of different mutations during dense colonization revealed the dynamic nature of intestinal microbial populations. We identified genes that are crucial for early and late stages of dense gut colonization and confirmed their role by testing isogenic mutants in in vivo competition assays with wild-type CR-Kp Screening of the transposon library also identified mutations that enhanced in vivo CR-Kp growth. These newly identified colonization factors may provide novel therapeutic opportunities to reduce intestinal colonization by CR-Kp IMPORTANCE Klebsiella pneumoniae is a common cause of bloodstream infections in immunocompromised and hospitalized patients, and over the last 2 decades, some strains have acquired resistance to nearly all available antibiotics, including broad-spectrum carbapenems. The U.S. Centers for Disease Control and Prevention has listed carbapenem-resistant K. pneumoniae (CR-Kp) as an urgent public health threat. Dense colonization of the intestine by CR-Kp and other antibiotic-resistant bacteria is associated with an increased risk of bacteremia. Reducing the density of gut colonization by CR-Kp is likely to reduce their transmission from patient to patient in health care facilities as well as systemic infections. How CR-Kp expands and persists in the gut lumen, however, is poorly understood. Herein, we generated a highly saturated mutant library in a multidrug-resistant K. pneumoniae strain and identified genetic factors that are associated with dense gut colonization by K. pneumoniae This study sheds light on host colonization by K. pneumoniae and identifies potential colonization factors that contribute to high-density persistence of K. pneumoniae in the intestine.

Dataset Information

OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo.

Publications

OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo.

Similar Datasets

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