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We identified a chromosomal qnrB19 gene within a transposon in a colistin-resistant Escherichia coli strain isolated from the stool sample of an Ecuadorian resident. This finding suggests a more stable acquisition of quinolone resistance on chromosomes than that on plasmids and the potential for propagation to other DNA structures.

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Pluralibacter gergoviae is a member of the Enterobacteriaceae family that has been reported sporadically. Although P. gergoviae strains exhibiting multidrug-resistant profiles have been identified an in-depth genomic analysis focusing on antimicrobial resistance (AMR) has been lacking, and was therefore performed in this study. Forty-eight P. gergoviae strains, isolated from humans, animals, foods, and the environment during 1970-2023, were analyzed. A large number of single-nucleotide polymorphisms were found, indicating a highly diverse population. Whilst P. gergoviae strains were found to be circulating at the One Health interface, only human and environmental strains exhibited multidrug resistance genotypes. Sixty-one different antimicrobial resistance genes (ARGs) were identified, highlighting genes encoding mobile colistin resistance, carbapenemases, and extended-spectrum ß-lactamases. Worryingly, the co-occurrence of mcr-9.1, blaKPC-2, blaCTX-M-9, and blaSHV-12, as well as mcr-10.1, blaNDM-5, and blaSHV-7, was detected. Plasmid sequences were identified as carrying clinically important ARGs, evidencing IncX3 plasmids harboring blaKPC-2, blaNDM-5, or blaSHV-12 genes. Virulence genotyping underlined P. gergoviae as being a low-virulence species. In this regard, P. gergoviae is emerging as a new multidrug-resistant species belonging to the Enterobacteriaceae family. Therefore, continuous epidemiological genomic surveillance of P. gergoviae is required.

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The presence of crpP was established in 201 Pseudomonas aeruginosa isolates from 9 Peruvian hospitals. The 76.6% (154/201) of the isolates presented the crpP gene. Overall, 123/201 (61.2%) isolates were non-susceptible to ciprofloxacin. The prevalence of crpP-possessing P. aeruginosa in Peru is higher than in other geographical areas.

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OBJECTIVES: In contrast to other qnr families, qnrVC has been reported mainly in Vibrio spp. and inserted in class 1 integrons. This study aimed to identify the variants of qnrVC genes detected in Klebsiella pneumoniae carbapenemase-2-producing Enterobacter and Klebsiella strains isolated from Brazilian coastal waters and the genetic contexts associated with their occurrence. METHODS: qnrVC variants were identified by Sanger sequencing. Stains were typified by pulsed-field gel electrophoresis. Antimicrobial susceptibility testing, conjugation assays, and whole genome sequencing (WGS) were applied to identify the strains' antimicrobial resistance profile, qnrVC and blaKPC-2 co-transference, and qnrVC genetic context. RESULTS: qnrVC1 was identified in 15 Enterobacter and 3 Klebsiella, and qnrVC4 in 2 Enterobacter strains. Pulsed-field gel electrophoresis revealed 12 clonal profiles of Enterobacter and one of Klebsiella. Strains were resistant to aminoglycosides, beta-lactams, fosfomycin, quinolones, and sulfamethoxazole-trimethoprim. Co-transference of qnrVC and blaKPC-2 were obtained from five representative Enterobacter strains, which showed resistance to ampicillin and amoxicillin-clavulanate, and reduced susceptibility to extended-spectrum cephalosporins, meropenem, and ciprofloxacin. WGS analysis from representative strains revealed one K. quasipneumoniae subsp. similipneumoniae, one E. soli, four E. kobei, and seven isolates belonging to Enterobacter Taxon 3. Long-read WGS showed qnrVC and blaKPC-2 were carried by the same replicon on Klebsiella and Enterobacter strains, and the qnrVC association with not previously described genetic environments composed of insertion sequences and truncated genes. These contexts occurred in small- and high-molecular-weight plasmids belonging to IncFII, IncP6, pKPC-CAV1321, and IncU groups. CONCLUSION: Our results suggest that the dissemination of qnrVC among Enterobacterales in Brazilian coastal waters is associated with several genetic recombination events.

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The increasing prevalence of multi-drug resistant (MDR) Escherichia coli in distinct ecological niches, comprising water sources and food-producing animals, such as fish species, has been widely reported. In the present study, quinolone-resistant E. coli isolates from Arapirama gigas, a major fish species in the Brazilian Amazon rivers and fish farms, were characterized regarding their antimicrobial susceptibility, virulence, and genetic diversity. A total of forty (40) specimens of A. gigas, including 20 farmed and 20 wild fish, were included. Thirty-four quinolone-resistant E. coli isolates were phenotypically tested by broth microdilution, while resistance and virulence genes were detected by PCR. Molecular epidemiology and genetic relatedness were analyzed by MLST and PFGE typing. The majority of isolates were classified as MDR and detected harboring blaCTX-M, qnrA and qnrB genes. Enterotoxigenic E. coli pathotype (ETEC) isolates were presented in low prevalence among farmed animals. MLST and PFGE genotyping revealed a wide genetic background, including the detection of internationally spread clones. The obtained data point out A. gigas as a reservoir in Brazilian Amazon aquatic ecosystems and warns of the interference of AMR strains in wildlife and environmental matrices.

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In view of growing concerns, in a One Health context, regarding the transport and dissemination of pathogenic microorganisms among seabirds and other vertebrate animals, including humans, the aim of this study was to identify Salmonella spp. in stranded and non-stranded resident and migratory wild seabirds from the Brazilian coast. Antimicrobial susceptibility and molecular profiles, quinolone resistance genes and antigenic characterization of the isolates were also carried out. Fresh faeces and cloacal swabs were obtained totaling 122 seabirds sampled throughout different Brazilian coast regions. At the laboratory, sample culturing, Salmonella spp. isolation and biochemical identification were performed, followed by antigenic profile identification by serum agglutination, susceptibility profile characterization by the agar disc diffusion technique, detection of quinolone resistance genes (qnrA, qnrB, qnrS) using the multiplex polymerase chain reaction technique (multiplex PCR) and, finally, isolates profiles identification by pulsed field gel electrophoresis (PFGE). Salmonella enterica subsp. enterica was identified in 7% of the studied birds, comprising three different serovars: Panama (63 %), Typhimurium (25 %) and Newport (13 %). The most important findings reported herein are the first description of Salmonella panama in seabirds and the totality of isolates being resistant (or intermediate) to at least one tested antimicrobial, with emphasis on quinolone resistance. The molecular results suggest that the observed resistance cannot be explained by the presence of plasmid-mediated quinolone resistance genes. The PFGE suggests that the Panama and Newport profiles detected herein are not yet widespread in Brazil, unlike Typhimurium, which is already well distributed throughout the country. Considering this finding, we suggest that seabirds are an important link in the epidemiological chain of this serovar. The monitoring of these bacteria in seabirds, as well as of their susceptibility profiles to antimicrobials, must be continuous, strengthening the role of these animals as environmental health indicators and sentinels.

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We investigated the phenotypic and molecular characteristics of Extended-Spectrum-ß-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae clinical isolates from four health-care institutions in Hermosillo, Sonora, Mexico. ESBL-producing isolates were collected from February to August 2016. The prevalence of ESBL-producing E. coli and K. pneumoniae was 11.9 and 8.7%, respectively. High dissemination of resistance to ciprofloxacin (88%), trimethoprim/sulfamethoxazole (72%) and aminoglycosides (59%) were detected, as well as susceptibility to meropenem, amikacin and tigecycline. The ESBL found variants were CTX-M-1 (88%) and CTX-M-9 (5%). The plasmid-mediated quinolone resistance (PMQR) gene aac(6´)-Ib-cr was identified in 62% of a representative sample, whereas the qnrB and qnrS genes were detected in 49% of the isolates. PFGE analyses detected many unrelated clones among the hospital or community isolates. A constant programme of epidemiological surveillance is recommended to understand the dynamics of bacterial resistance to both cephalosporin as well as the fluoroquinolone family of antibiotics.

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OBJECTIVES: This study aimed to evaluate the persistence of the plasmid-mediated quinolone resistance (PMQR) among uropathogenic Escherichia coli strains grown under or without exposure to subinhibitory concentrations of ciprofloxacin. Based on that, we evaluated the possible spontaneous loss or maintenance of PMQR and the possible appearance of compensatory mutations in gyrA and parC genes. METHODS: Three uropathogenic E. coli strains harbouring chromosomal mutations in the gyrA and/or parC genes coupled with qnrS1 or qnrB2 determinants carried by distinct plasmid sizes and incompatibility N groups (IncN/ST1, IncN/ST5) were evaluated using in vitro and in vivo assays. RESULTS: PMQRs remained stable in all strains throughout the generations evaluated, independently of exposure to ciprofloxacin in both in vivo and in vitro assays. Analysis of gyrA and parC genes after in vivo and in vitro assays revealed that no changes occurred in quinolone-resistance determining regions (QRDR). CONCLUSION: We demonstrated that IncN plasmids were persistent over 14 days in E. coli clinical strains independently of exposure to ciprofloxacin, as well as previous mutations in QRDR.

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[This corrects the article DOI: 10.3389/fmicb.2019.02503.].

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Antimicrobial resistance is an increasing problem worldwide, and Salmonella spp. resistance to quinolone was classified by WHO in the high priority list. Recent studies in Europe and in the US reported the presence of small plasmids carrying quinolone resistance in Enterobacteriaceae isolated from poultry and poultry products. The aims of this study were to identify and characterize plasmid-mediated quinolone resistance in Salmonella spp. and to investigate transduction as a possible mechanism associated to its dissemination. First, we assessed resistance to nalidixic acid and/or ciprofloxacin in 64 Salmonella spp. and detected resistance in eight of them. Genomic analyses determined that six isolates of different serotypes and sources carried an identical 2.7-kb plasmid containing the gene qnrB19 which confers quinolone resistance. The plasmid detected also has high identity with plasmids reported in the US, Europe, and South America. The presence of similar plasmids was later surveyed by PCR in a local Salmonella collection (n = 113) obtained from diverse sources: food (eggs), wild and domestic animals (pigs, horse, chicken), and human clinical cases. qnrB19-carrying plasmids were found in 8/113 Salmonella tested strains. A bioinformatics analysis including Chilean and previously described plasmids revealed over 95.0% of nucleotide identity among all the sequences obtained in this study. Furthermore, we found that a qnrB19-carrying plasmid can be transferred between Salmonella of different serotypes through a P22-mediated transduction. Altogether our results demonstrate that plasmid-mediated quinolone resistance (PMQR) is widespread in Salmonella enterica of different serotypes isolated from human clinical samples, wild and domestic animals, and food in Chile and suggest that transduction could be a plausible mechanism for its dissemination. The occurrence of these antimicrobial resistance elements in Salmonella in a widespread area is of public health and food safety concern, and it indicates the need for increased surveillance for the presence of these plasmids in Salmonella strains and to assess their actual impact in the rise and spread of quinolone resistance.