Novel Carbapenem-Hydrolyzing β-Lactamase, KPC-1, from a Carbapenem-Resistant Strain of Klebsiella pneumoniae
Ontology highlight
ABSTRACT:
SUBMITTER: Yigit H
PROVIDER: S-EPMC2224771 | biostudies-literature | 2008 Feb
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:A Klebsiella pneumoniae isolate showing moderate to high-level imipenem and meropenem resistance was investigated. The MICs of both drugs were 16 microg/ml. The beta-lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. The strain was also resistant to extended-spectrum cephalosporins and aztreonam. Isoelectric focusing studies demonstrated three beta-lactamases, with pIs of 7.2 (SHV-29), 6.7 (KPC-1), and 5.4 (TEM-1). The presence of bla(SHV) and bla(TEM) genes was confirmed by specific PCRs and DNA sequence analysis. Transformation and conjugation studies with Escherichia coli showed that the beta-lactamase with a pI of 6.7, KPC-1 (K. pneumoniae carbapenemase-1), was encoded on an approximately 50-kb nonconjugative plasmid. The gene, bla(KPC-1), was cloned in E. coli and shown to confer resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The amino acid sequence of the novel carbapenem-hydrolyzing beta-lactamase, KPC-1, showed 45% identity to the pI 9.7 carbapenem-hydrolyzing beta-lactamase, Sme-1, from Serratia marcescens S6. Hydrolysis studies showed that purified KPC-1 hydrolyzed not only carbapenems but also penicillins, cephalosporins, and monobactams. KPC-1 had the highest affinity for meropenem. The kinetic studies also revealed that clavulanic acid and tazobactam inhibited KPC-1. An examination of the outer membrane proteins of the parent K. pneumoniae strain demonstrated that the strain does not express detectable levels of OmpK35 and OmpK37, although OmpK36 is present. We concluded that carbapenem resistance in K. pneumoniae strain 1534 is mainly due to production of a novel Bush group 2f, class A, carbapenem-hydrolyzing beta-lactamase, KPC-1, although alterations in porin expression may also play a role.
| S-EPMC90438 | biostudies-literature
Project description:We investigated a Klebsiella oxytoca isolate demonstrating resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The MICs of both imipenem and meropenem were 32 microg/ml. The beta-lactamase activity against imipenem and meropenem was inhibited in the presence of clavulanic acid. Isoelectric focusing studies demonstrated five beta-lactamases with pIs of 8.2 (SHV-46), 6.7 (KPC-2), 6.5 (unknown), 6.4 (probable OXY-2), and 5.4 (TEM-1). The presence of the bla(SHV) and bla(TEM) genes was confirmed by specific PCR assays and DNA sequence analysis. Transformation and conjugation studies with Escherichia coli showed that the beta-lactamase with a pI of 6.7, Klebsiella pneumoniae carbapenemase-2 (KPC-2), was encoded on an approximately 70-kb conjugative plasmid that also carried SHV-46, TEM-1, and the beta-lactamase with a pI of 6.5. The bla(KPC-2) determinant was cloned in E. coli and conferred resistance to imipenem, meropenem, extended-spectrum cephalosporins, and aztreonam. The amino acid sequence of KPC-2 showed a single amino acid difference, S174G, when compared with KPC-1, another carbapenem-hydrolyzing beta-lactamase from K. pneumoniae 1534. Hydrolysis studies showed that purified KPC-2 hydrolyzed not only carbapenems but also penicillins, cephalosporins, and aztreonam. KPC-2 had the highest affinity for meropenem. The kinetic studies revealed that KPC-2 was inhibited by clavulanic acid and tazobactam. An examination of the outer membrane proteins of the parent K. oxytoca strain demonstrated that it expressed detectable levels of OmpK36 (the homolog of OmpC) and a higher-molecular-weight OmpK35 (the homolog of OmpF). Thus, carbapenem resistance in K. oxytoca 3127 is due to production of the Bush group 2f, class A, carbapenem-hydrolyzing beta-lactamase KPC-2. This beta-lactamase is likely located on a transposon that is part of a conjugative plasmid and thus has a very high potential for dissemination.
| S-EPMC296202 | biostudies-literature
Project description:From April 2000 to April 2001, 24 patients in intensive care units at Tisch Hospital, New York, N.Y., were infected or colonized by carbapenem-resistant Klebsiella pneumoniae. Pulsed-field gel electrophoresis identified a predominant outbreak strain, but other resistant strains were also recovered. Three representatives of the outbreak strain from separate patients were studied in detail. All were resistant or had reduced susceptibility to imipenem, meropenem, ceftazidime, piperacillin-tazobactam, and gentamicin but remained fully susceptible to tetracycline. PCR amplified a blaKPC allele encoding a novel variant, KPC-3, with a His(272)-->Tyr substitution not found in KPC-2; other carbapenemase genes were absent. In the outbreak strain, KPC-3 was encoded by a 75-kb plasmid, which was transferred in vitro by electroporation and conjugation. The isolates lacked the OmpK35 porin but expressed OmpK36, implying reduced permeability as a cofactor in resistance. This is the third KPC carbapenem-hydrolyzing beta-lactamase variant to have been reported in members of the Enterobacteriaceae, with others reported from the East Coast of the United States. Although producers of these enzymes remain rare, the progress of this enzyme group merits monitoring.
| S-EPMC529220 | biostudies-literature
Project description:Klebsiella pneumoniae KP3 was isolated from a patient transferred from India to the Sultanate of Oman. K. pneumoniae KP3 was resistant to all β-lactams, including carbapenems, and expressed the carbapenem-hydrolyzing β-lactamase OXA-181, which differs from OXA-48 by four amino acid substitutions. Compared to OXA-48, OXA-181 possessed a very similar hydrolytic profile. The bla(OXA-181) gene was located on a 7.6-kb ColE-type plasmid and was linked to the insertion sequence ISEcp1. The ISEcp1-mediated one-ended transposition of bla(OXA-181) was also demonstrated.
| S-EPMC3186949 | biostudies-literature
Project description:A Klebsiella pneumoniae clinical isolate recovered in Tunisia showed resistance to all β-lactams and decreased susceptibility to carbapenems. K. pneumoniae 204 expressed the carbapenem-hydrolyzing β-lactamase OXA-204, differing from OXA-48 by two amino acid substitutions (Gln98His and Thr99Arg) (class D β-lactamase [DBL] numbering). OXA-48 and OXA-204 shared similar resistance profiles, hydrolyzing carbapenems but sparing broad-spectrum cephalosporins. The bla(OXA-204) gene was located on a ca. 150-kb IncA/C-type plasmid, which also carried the bla(CMY-4) gene. The bla(OXA-204) gene was associated with an ISEcp1 element, whereas the bla(OXA-48) genes are usually associated with IS1999.
| S-EPMC3535949 | biostudies-literature
Project description:Thirty-nine bla(KPC)-producing isolates of the family Enterobacteriaceae with carbapenem resistance or reduced carbapenem susceptibility were obtained from inpatients from eight hospitals in six cities of three provinces in eastern China. The pulsed-field gel electrophoresis analysis of all 36 Klebsiella pneumoniae isolates revealed six major patterns. The resistant plasmids of most isolates were successfully transferred by conjugation and evaluated experimentally to be 40 to 180 kb in size. A 20.2-kb bla(KPC)-surrounding nucleotide sequence from plasmid pKP048 has been obtained and contains an integration structure of a Tn3-based transposon and partial Tn4401 segment, with the gene order Tn3-transposase, Tn3-resolvase, ISKpn8, the bla(KPC-2) gene, and the ISKpn6-like element. The chimera of several transposon-associated elements indicated a novel genetic environment of the K. pneumoniae carbapenemase beta-lactamase gene in isolates from China.
| S-EPMC2764158 | biostudies-literature
Project description:We isolated and characterized a carbapenem-resistant Klebsiella pneumoniae (CRKP) clinical strain from blood carrying a novel bla OXA gene, bla OXA-926, and belonging to ST29, an uncommon CRKP type. The strain, 130002, was genome sequenced using both short- and long-read sequencing and has a 94.9-kb self-transmissible IncFII plasmid carrying bla KPC-2. K. pneumoniae genomes of the ST29 complex (ST29 and its single-allele variants) were retrieved and were subjected to single nucleotide polymorphism-based phylogenomic analysis. A total of 157 genomes of the ST29 complex were identified. This complex is commonly associated with extended-spectrum β-lactamase-encoding genes, in particular, bla CTX-M-15 but rarely has carbapenemase genes. The novel plasmid-encoded β-lactamase-encoding gene bla OXA-926 was identified on a 117.8-kb IncFIA-IncFII plasmid, which was transferrable in the presence of the bla KPC-2-carrying plasmid. bla OXA-926 was cloned and MICs of β-lactams in the transformants were determined using microdilution. OXA-926 has a narrow spectrum conferring reduced susceptibility only to piperacillin, piperacillin-tazobactam, and cephalothin. Avibactam cannot fully inhibit OXA-926. bla OXA-926 and its variants have been seen in Klebsiella strains in Asia and Brazil. OXA-926 is the closest in sequence identity (89.9%) to a chromosome-encoding OXA-type enzyme of Variovorax guangxiensis. In conclusion, OXA-926 is novel plasmid-borne narrow-spectrum β-lactamase that cannot be fully inhibited by avibactam. It is likely that bla OXA-926 originates from a species closely related to V. guangxiensis and was introduced into Klebsiella > 10 years ago.
| S-EPMC8430219 | biostudies-literature
Project description:Isolates coproducing serine/metallo-carbapenems are a serious emerging public health threat, given their rapid dissemination and the limited number of treatment options. The purposes of this study were to evaluate the in vitro antibacterial activity of novel β-lactam-β-lactamase inhibitor combinations (BLBLIs) against carbapenem-resistant Klebsiella pneumoniae (CRKP) coproducing metallo-β-lactamase and serine-β-lactamase, and to explore their effects in combination with aztreonam, meropenem, or polymyxin in order to identify the best therapeutic options. Four CRKP isolates coproducing K. pneumoniae carbapenemase (KPC) and New Delhi metallo-β-lactamase (NDM) were selected, and a microdilution broth method was used to determine their susceptibility to antibiotics. Time-kill assay was used to detect the bactericidal effects of the combinations of antibiotics. The minimum inhibitory concentration (MIC) values for imipenem and meropenem in three isolates did not decrease after the addition of relebactam or varbobactam, but the addition of avibactam to aztreonam reduced the MIC by more than 64-fold. Time-kill assay demonstrated that imipenem-cilastatin/relebactam (ICR) alone exerted a bacteriostatic effect against three isolates (average reduction: 1.88 log10 CFU/mL) and ICR combined with aztreonam exerted an additive effect. Aztreonam combined with meropenem/varbobactam (MEV) or ceftazidime/avibactam (CZA) showed synergistic effects, while the effect of aztreonam combined with CZA was inferior to that of MEV. Compared with the same concentration of aztreonam plus CZA combination, aztreonam/avibactam had a better bactericidal effect (24 h bacterial count reduction >3 log10CFU/mL). These data indicate that the combination of ATM with several new BLBLIs exerts powerful bactericidal activity, which suggests that these double β-lactam combinations might provide potential alternative treatments for infections caused by pathogens coproducing-serine/metallo-carbapenems.
| S-EPMC10949892 | biostudies-literature
Project description:Carbapenem-resistant Enterobacteriaceae (CRE) are resistant to most antibiotics, making CRE infections extremely difficult to treat with available agents. Klebsiella pneumoniae carbapenemases (KPC-2 and KPC-3) are predominant carbapenemases in CRE in the United States. Nacubactam is a bridged diazabicyclooctane (DBO) β-lactamase inhibitor that inactivates class A and C β-lactamases and exhibits intrinsic antibiotic and β-lactam "enhancer" activity against Enterobacteriaceae In this study, we examined a collection of meropenem-resistant K. pneumoniae isolates carrying blaKPC-2 or blaKPC-3; meropenem-nacubactam restored susceptibility. Upon testing isogenic Escherichia coli strains producing KPC-2 variants with single-residue substitutions at important Ambler class A positions (K73, S130, R164, E166, N170, D179, K234, E276, etc.), the K234R variant increased the meropenem-nacubactam MIC compared to that for the strain producing KPC-2, without increasing the meropenem MIC. Correspondingly, nacubactam inhibited KPC-2 (apparent Ki [Ki app] = 31 ± 3 μM) more efficiently than the K234R variant (Ki app = 270 ± 27 μM) and displayed a faster acylation rate (k2/K), which was 5,815 ± 582 M-1 s-1 for KPC-2 versus 247 ± 25 M-1 s-1 for the K234R variant. Unlike avibactam, timed mass spectrometry revealed an intact sulfate on nacubactam and a novel peak (+337 Da) with the K234R variant. Molecular modeling of the K234R variant showed significant catalytic residue (i.e., S70, K73, and S130) rearrangements that likely interfere with nacubactam binding and acylation. Nacubactam's aminoethoxy tail formed unproductive interactions with the K234R variant's active site. Molecular modeling and docking observations were consistent with the results of biochemical analyses. Overall, the meropenem-nacubactam combination is effective against carbapenem-resistant K. pneumoniae Moreover, our data suggest that β-lactamase inhibition by nacubactam proceeds through an alternative mechanism compared to that for avibactam.
| S-EPMC6658744 | biostudies-literature
Project description:The development of resistance to carbapenems in Klebsiella pneumoniae due to the production of metallo-β-lactamases (MBLs) is a critical public health problem because carbapenems are the last-resort drugs used for treating severe infections of extended-spectrum β-lactamases (ESBLs) producing K. pneumoniae. Restoring the activity of carbapenems by the inhibition of metallo-β-lactamases is a valuable approach to combat carbapenem resistance. In this study, two well-characterized clinical multidrug and carbapenem-resistant K. pneumoniae isolates were used. The sub-inhibitory concentrations of pantoprazole and the well-reported metallo-β-lactamase inhibitor captopril inhibited the hydrolytic activities of metallo-β-lactamases, with pantoprazole having more inhibiting activities. Both drugs, when used in combination with meropenem, exhibited synergistic activities. Pantoprazole could also downregulate the expression of the metallo-β-lactamase genes bla NDM and bla VIM. A docking study revealed that pantoprazole could bind to and chelate zinc ions of New Delhi and Verona integron-encoded MBL (VIM) enzymes with higher affinity than the control drug captopril and with comparable affinity to the natural ligand meropenem, indicating the significant inhibitory activity of pantoprazole against metallo-β-lactamases. In conclusion, pantoprazole can be used in combination with meropenem as a new strategy for treating serious infections caused by metallo-β-lactamases producing K. pneumoniae.
| S-EPMC10963397 | biostudies-literature