Neisseria cinerea with High Ceftriaxone MIC Is a Source of Ceftriaxone and Cefixime Resistance-Mediating penA Sequences in Neisseria gonorrhoeae.
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ABSTRACT:
SUBMITTER: Igawa G
PROVIDER: S-EPMC5826163 | biostudies-literature | 2018 Mar
REPOSITORIES: biostudies-literature
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Project description:OBJECTIVES: To examine mutations within the penA, mtrR, porB, ponA and pilQ genes of Neisseria gonorrhoeae to determine their contribution to cephalosporin resistance. METHODS: A total of 46 N. gonorrhoeae isolates with reduced susceptibility to cefixime or ceftriaxone (MICs > or = 0.12 mg/L) and two susceptible isolates were selected. The full sequence of penA and partial sequences previously reported as hot mutation sites of the other genes were analysed. Genotyping by N. gonorrhoeae multiantigen sequence typing (NG-MAST) was also performed. RESULTS: A mosaic penicillin-binding protein 2 (PBP 2) was found in a single isolate that exhibited the highest cefixime MIC (0.5 mg/L). The majority of the isolates with reduced susceptibility to cephalosporins contained non-mosaic PBP 2 sequences, of which PBP 2 pattern XIII was most common (28/46). All isolates with reduced susceptibility to cephalosporins also had mtrR and porB mutations. Two susceptible isolates had the PBP 2 pattern XIV and an incomplete MtrR protein, which was a new mutation. Isolates with identical PBP 2 patterns comprised multiple NG-MAST sequence types. CONCLUSIONS: Reduced susceptibility of N. gonorrhoeae to ceftriaxone and cefixime was associated with diverse penA mutations, particularly PBP 2 pattern XIII containing an Ala-501-->Val substitution, together with mtrR and porB mutations. The existence of only one strain having the mosaic penA sequence indicated that ceftriaxone and cefixime resistance in Korea is mostly not associated with a mosaic penA sequence. Highly heterogeneous NG-MAST sequence types excluded the clonal expansion of a particular subtype.
| S-EPMC2837549 | biostudies-literature
Project description:In Neisseria gonorrhoeae, the mosaic type of penA, which encodes penicillin-binding protein 2 (PBP 2), is associated with reduced susceptibility to oral cephalosporins. To investigate the relatedness of N. gonorrhoeae clinical isolates with reduced susceptibility, we sequenced the penA genes of 32 isolates. Five different amino acid sequence types of PBP 2 were identified, but all seemed to be derivatives of pattern X of PBP 2 (PBP 2-X). However, multilocus sequence typing of the isolates showed that the isolates belonged to six different sequence types. As PBP 2-X was identified in three different sequence types, horizontal transfer of the penA allele encoding PBP2-X was suggested. We demonstrated that the penA gene could be transferred from an isolate with reduced susceptibility to a sensitive isolate by natural transformation. Comparison of the sequence of the penA-flanking regions of 12 transformants with those of the donor and the recipient suggested that at least a 4-kb DNA segment, including the penA gene, was transferred. During horizontal transfer, some of the penA alleles also acquired variations due to point mutations and genetic exchange within the allele. Our results provide evidence that the capacity for natural transformation in N. gonorrhoeae plays a role in the spread of chromosomal antibiotic resistance genes and the generation of diversity in such genes.
| S-EPMC2826007 | biostudies-literature
Project description: Not available
| S-EPMC8202096 | biostudies-literature
Project description:Recently, the first Neisseria gonorrhoeae strain (H041) highly resistant to the expanded-spectrum cephalosporins (ESCs) ceftriaxone and cefixime, which are the last remaining options for first-line gonorrhea treatment, was isolated in Japan. Here, we confirm and characterize a second strain (F89) with high-level cefixime and ceftriaxone resistance which was isolated in France and most likely caused a treatment failure with cefixime. F89 was examined using six species-confirmatory tests, antibiograms (33 antimicrobials), porB sequencing, N. gonorrhoeae multiantigen sequence typing (NG-MAST), multilocus sequence typing (MLST), and sequencing of known gonococcal resistance determinants (penA, mtrR, penB, ponA, and pilQ). F89 was assigned to MLST sequence type 1901 (ST1901) and NG-MAST ST1407, which is a successful gonococcal clone that has spread globally. F89 has high-level resistance to cefixime (MIC = 4 μg/ml) and ceftriaxone (MIC = 1 to 2 μg/ml) and resistance to most other antimicrobials examined. A novel penA mosaic allele (penA-CI), which was penA-XXXIV with an additional A501P alteration in penicillin-binding protein 2, was the primary determinant for high-level ESC resistance, as determined by transformation into a set of recipient strains. N. gonorrhoeae appears to be emerging as a superbug, and in certain circumstances and settings, gonorrhea may become untreatable. Investigations of the biological fitness and enhanced understanding and monitoring of the ESC-resistant clones and their international transmission are required. Enhanced disease control activities, antimicrobial resistance control and surveillance worldwide, and public health response plans for global (and national) perspectives are also crucial. Nevertheless, new treatment strategies and/or drugs and, ideally, a vaccine are essential to develop for efficacious gonorrhea management.
| S-EPMC3294892 | biostudies-literature
Project description:All strains of Neisseria gonorrhoeae with reduced susceptibility to ceftriaxone and cefixime (cephalosporin-intermediate-resistant [Ceph(i)] strains) contain a mosaic penA allele encoding penicillin-binding protein 2 (PBP 2) with nearly 60 amino acid differences compared to the sequence of wild-type PBP 2, together with a set of resistance determinants (i.e., mtrR, penB, and/or ponA1) that are required for high-level penicillin resistance. To define the individual contributions of these determinants to reduced susceptibility to ceftriaxone and cefixime, we created isogenic strains containing the mosaic penA allele from the Ceph(i) strain 35/02 (penA35) together with one or more of the other resistance determinants and determined the MICs of penicillin G, ceftriaxone, and cefixime. The majority of cefixime resistance is conferred by the penA35 allele, with only a small contribution coming from mtrR and penB, whereas ceftriaxone resistance is nearly equally dependent upon mtrR and penB. Unlike high-level penicillin resistance, the ponA1 allele does not appear to be important for Ceph(i). A strain containing all four determinants has increased resistance to ceftriaxone and cefixime but not to the levels that the donor Ceph(i) strain does, suggesting that Ceph(i) strains, similar to high-level-penicillin-resistant strains, contain an additional unknown determinant that is required to reach donor levels of resistance. Our data also suggest that the original Ceph(i) strains arose from the transformation of penA genes from commensal Neisseria species into a penicillin-resistant strain already harboring mtrR, penB, ponA1, and the unknown gene(s) involved in high-level penicillin resistance.
| S-EPMC2737842 | biostudies-literature
Project description:We have characterized in detail a new ceftriaxone- and multidrug-resistant Neisseria gonorrhoeae strain (FC428) isolated in Japan in 2015. FC428 differed from previous ceftriaxone-resistant strains and contained a novel mosaic penA allele encoding a new mosaic penicillin-binding protein 2 (PBP 2). However, the resistance-determining 3'-terminal region of penA was almost identical to the regions of two previously reported ceftriaxone-resistant strains from Australia and Japan, indicating that both ceftriaxone-resistant strains and conserved ceftriaxone resistance-determining PBP 2 regions might spread.
| S-EPMC4914677 | biostudies-literature
Project description:We identified a ceftriaxone-resistant Neisseria gonorrhoeae isolate in a patient in Canada. This isolate carried the penA-60 allele, which differs substantially from its closest relative, mosaic penA XXVII (80% nucleotide identity). Epidemiologic and genomic data suggest spread from Asia. Antimicrobial susceptibility surveillance helps prevent spread of highly resistant N. gonorrhoeae strains.
| S-EPMC5782888 | biostudies-literature
Project description:Neisseria gonorrhoeae strains with reduced susceptibility to cefixime (MICs, 0.25 to 0.5 micro g/ml) were isolated from male urethritis patients in Tokyo, Japan, in 2000 and 2001. The resistance to cephems including cefixime and penicillin was transferred to a susceptible recipient, N. gonorrhoeae ATCC 19424, by transformation of the penicillin-binding protein 2 gene (penA) that had been amplified by PCR from a strain with reduced susceptibility to cefixime (MIC, 0.5 micro g/ml). The sequences of penA in the strains with reduced susceptibilities to cefixime were different from those of other susceptible isolates and did not correspond to the reported N. gonorrhoeae penA gene sequences. Some regions in the transpeptidase-encoding domain in this penA gene were similar to those in the penA genes of Neisseria perflava (N. sicca), Neisseria cinerea, Neisseria flavescens, and Neisseria meningitidis. These results showed that a mosaic-like structure in the penA gene conferred reductions in the levels of susceptibility of N. gonorrhoeae to cephems and penicillin in a manner similar to that found for N. meningitidis and Streptococcus pneumoniae.
| S-EPMC132769 | biostudies-literature
Project description:Increasing numbers of Neisseria gonorrhoeae strains with decreased susceptibilities to ceftriaxone and other oral cephalosporins widely used for the treatment of gonorrhea have been isolated in Sydney, Australia, over several years. In this study, we examined the complete penicillin-binding protein 2 (PBP 2) amino acid sequences of 109 gonococci, selected on the basis of their diverse temporal and geographic origins and because they exhibited a range of ceftriaxone MICs: < OR =0.03 microg/ml (n = 59), 0.06 microg/ml (n = 43), and 0.125 microg/ml (n = 7). Auxotyping, serotyping, and genotyping by N. gonorrhoeae multiantigen sequence typing sequence-based analysis was also performed. In total, 20 different amino acid sequence patterns were identified, indicating considerable variation in the PBP 2 sequences in this study sample. Only some of the N. gonorrhoeae isolates with significantly higher ceftriaxone MICs contained a mosaic PBP 2 pattern, while more isolates exhibited a nonmosaic PBP 2 pattern containing an A501V substitution. Although particular N. gonorrhoeae genotypes in our sample were shown to be less susceptible to ceftriaxone, the reduced susceptibility to ceftriaxone was not specific to any particular genotype and was observed in a broad range of auxotypes, serotypes, and genotypes. Overall, the results of our study show that N. gonorrhoeae strains exhibiting reduced sensitivity to ceftriaxone are not of a particular subtype and that a number of different mutations in PBP 2 may contribute to this phenomenon.
| S-EPMC2043202 | biostudies-literature
Project description:Resistance to ceftriaxone in Neisseria gonorrhoeae is mainly conferred by mosaic penA alleles that encode penicillin-binding protein 2 (PBP2) variants with markedly lower rates of acylation by ceftriaxone. To assess the impact of these mosaic penA alleles on gonococcal fitness, we introduced the mosaic penA alleles from two ceftriaxone-resistant (Cror) clinical isolates (H041 and F89) into a Cros strain (FA19) by allelic exchange and showed that the resultant Cror mutants were significantly outcompeted by the Cros parent strain in vitro and in a murine infection model. Four Cror compensatory mutants of FA19 penA41 were isolated independently from mice that outcompeted the parent strain both in vitro and in vivo One of these compensatory mutants (LV41C) displayed a unique growth profile, with rapid log growth followed by a sharp plateau/gradual decline at stationary phase. Genome sequencing of LV41C revealed a mutation (G348D) in the acnB gene encoding the bifunctional aconitate hydratase 2/2 methylisocitrate dehydratase. Introduction of the acnBG348D allele into FA19 penA41 conferred both a growth profile that phenocopied that of LV41C and a fitness advantage, although not as strongly as that exhibited by the original compensatory mutant, suggesting the existence of additional compensatory mutations. The mutant aconitase appears to be a functional knockout with lower activity and expression than wild-type aconitase. Transcriptome sequencing (RNA-seq) analysis of FA19 penA41 acnBG348D revealed a large set of upregulated genes involved in carbon and energy metabolism. We conclude that compensatory mutations can be selected in Cror gonococcal strains that increase metabolism to ameliorate their fitness deficit.IMPORTANCE The emergence of ceftriaxone-resistant (Cror) Neisseria gonorrhoeae has led to the looming threat of untreatable gonorrhea. Whether Cro resistance is likely to spread can be predicted from studies that compare the relative fitnesses of susceptible and resistant strains that differ only in the penA gene that confers Cro resistance. We showed that mosaic penA alleles found in Cror clinical isolates are outcompeted by the Cros parent strain in vitro and in vivo but that compensatory mutations that allow ceftriaxone resistance to be maintained by increasing bacterial fitness are selected during mouse infection. One compensatory mutant that was studied in more detail had a mutation in acnB, which encodes the aconitase that functions in the tricarboxylic acid (TCA) cycle. This study illustrates that compensatory mutations can be selected during infection, which we hypothesize may allow the spread of Cro resistance in nature. This study also provides novel insights into gonococcal metabolism and physiology.
| S-EPMC5885032 | biostudies-literature