Mutations in porin LamB contribute to ceftazidime-avibactam resistance in KPC-producing Klebsiella pneumoniae

Abstract

Ceftazidime-avibactam (CAZ-AVI) shows promising activity against carbapenem-resistant Klebsiella pneumoniae (CRKP), however, CAZ-AVI resistance have emerged recently. Mutations in KPCs, porins OmpK35 and/or OmpK36, and PBPs are known to contribute to the resistance to CAZ-AVI in CRKP. To identify novel CAZ-AVI resistance mechanism, we generated 10 CAZ-AVI-resistant strains from 14 CAZ-AVI susceptible KPC-producing K. pneumoniae (KPC-Kp) strains through in vitro multipassage resistance selection using low concentrations of CAZ-AVI. Comparative genomic analysis for the original and derived mutants identified CAZ-AVI resistance-associated mutations in KPCs, PBP3 (encoded by ftsI), and LamB, an outer membrane maltoporin. CAZ-AVI susceptible KPC-Kp strains became resistant when complemented with mutated blaKPC genes. Complementation experiments also showed that a plasmid borne copy of wild-type lamB or ftsI gene reduced the MIC value of CAZ-AVI in the induced resistant strains. In addition, blaKPC expression level increased in four of the six CAZ-AVI-resistant strains without KPC mutations, indicating a probable association between increased blaKPC expression and increased resistance in these strains. In conclusion, we here identified a novel mechanism of CAZ-AVI resistance associated with mutations in porin LamB in KPC-Kp.

Antibiotic Resistance Diagnosis in ESKAPE Pathogens—A Review on Proteomic Perspective

“…One study reported the impact of colistin in decreasing the expression of the maltose transporter LamB, a porin involved in the influx of antibiotics and the class A β lactamases—TEM, SHV-11, and SHV-4 [ 165 ]. Comparative proteomic analysis of polymyxin-susceptible Klebsiella pneumoniae validated the role of crrB -mediated colistin resistance in which lipid A profiles presented the addition of one or two L-Ara4N molecules and palmitoylation with elevations in CrrAB, PmrAB, and ArnBCADT levels.…”

Molecular mechanisms underlying bacterial resistance to ceftazidime/avibactam

“…Resistance of A. baumannii strains to CAZ/AVI is due mainly to the failure of AVI to penetrate the outer membrane (Mushtaq et al, 2010). In addition to OmpC, OmpF, and their homologous proteins, the introduction of a wild-type Lamb into resistant strains carrying a variant Lamb with Arg33His and Arg374Leu substitutions results in a 2-fold reduction in the MIC values of these strains for CAZ/AVI, indicating that variant Lamb contributes to resistance to CAZ/AVI (Guo et al, 2021).…”

“…Culture of strains susceptible to CAZ/AVI in LB medium containing CAZ/AVI for 50 generations resulted in the generation of several variants of KPC‐2, such as a 165_166 Gln‐Leu insertion, a Leu169Pro insertion plus a Ser181 insertion, and a 166_167 Gln‐Leu deletion. Introduction of these bla KPC mutations into a wild‐type strain susceptible to CAZ/AVI increased the MIC values for CAZ/AVI from 2/4, 4/4, and 0.25/4 mg/L to 16/4, 128/4, and 32/4 mg/L, respectively, but did not affect MIC values for CAZ significantly, suggesting that these variants mainly affect the inhibitory activity of AVI (Guo et al, 2021 ).…”

“…The Leu169Pro amino acid substitution in PBP3 results in a significant increase in the MIC value for CAZ/AVI. Introduction of the wild‐type ftsl gene into the resistant strain reduces the MIC value for CAZ/AVI from 128/4 to 4/4 mg/L (Guo et al, 2021 ). Alterations in the PBP‐encoding gene ftsI are associated with CAZ/AVI resistance (Castanheira et al, 2019 ).…”

Clinical Risk Factors and Microbiological and Intestinal Characteristics of Carbapenemase-Producing Enterobacteriaceae Colonization and Subsequent Infection

“…Previous studies ( 3 – 5 ) on the treatment of CRE infections have been particularly focused mostly on new antibiotics, including β-lactam–β-lactamase inhibitor combinations (e.g., ceftazidime-avibactam, ceftolozane-tazobactam, and meropenem-vaborbactam), and other existing antibiotics (e.g., aminoglycosides, carbapenems, and tigecycline, etc.). However, these new antibiotics have been on the market in recent years yet drug resistance still appears worldwide ( 6 – 8 ). Therefore, the spread of CRE is a clinical and public health problem.…”