To characterize the location and genetic environments of qnr, aac(6′)-Ib-cr and qepA genes related to quinolone resistance in 19 Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca strains. Genetic environments of the indicated genes were studied by cloning, PCR mapping and sequencing. The location of these genes was analysed by S1-PFGE and PFGE–I-CeuI and hybridization with specific probes. Associated antibiotic resistance mechanisms and molecular typing of strains were also investigated. The studied strains carried the aac(6′)-Ib-cr, qepA, qnrS1, qnrB6, qnrB4 and oqxAB genes, with aac(6′)-Ib-cr being the most prevalent. E. coli strains belonged to sequence types (STs) ST648, ST131, ST224 and ST205, and K. pneumoniae strains to ST433, ST341, ST152, ST15 and ST431. Different genetic environments of quinolone resistance genes were observed, and some of them had not been previously detected and registered in GenBank. The aac(6′)-Ib-cr gene was mainly located in class 1 integrons or associated with the Tn1721 transposon in E. coli and associated with the aac(3)-II gene in Klebsiella. All these structures contained mechanisms of gene acquisition and/or dissemination, such as IS26. The studied quinolone resistance genes were mostly detected in IncF and IncN plasmids in E. coli and in IncR plasmids in Klebsiella, but in some strains the chromosomal location of the aac(6′)-Ib-cr gene was detected for the first time. The bla_CTX-M-15, bla_OXA-1, tet(A), aac(3)-II and aph(3′)-Ia genes and class 1 integrons were found in most strains. The aac(6′)-Ib-cr gene was detected for the first time in the chromosome, although a plasmidic location was the most frequently found, with differentiation of plasmids types in E. coli versus Klebsiella.

Background/Purpose: Uropathogenic E. coli (UPEC) is the main cause of urinary tract infection (UTI) and it is known that pregnant women have a higher risk for UTI. UPEC has a variety of virulence and antibiotic resistance factors that facilitate its pathogenic success and it is crucial to know which are the susceptibility patterns, Extended-Spectrum-β-Lactamase (ESBL) production, virulence genes, pathogenicity islands (PAI), phylogenetic groups and serotypes among strains isolated from pregnant and non-pregnant women. Methods: One hundred fifty UPEC strains were isolated from pregnant and non-pregnant women from two different Mexican states (Sonora and Puebla). Strains were analyzed using the Kirby-Bauer method for the determination of antibiotic susceptibility and ESBL. Virulence genes, PAIs and phylogenetic groups were determined using a multiplex PCR. Strains were serotyped by an agglutination assay. Blood agar and CAS agar were used for phenotypic assays. Results: 92.7% of UPEC strains showed multidrug-resistant (MDR), 6.7% extremely-resistant (XDR) and 0.6% pandrug-resistant (PDR). The highest resistance was determined to be for β-lactam antibiotics (> 72% in both states) and 44.5% of the UPEC strains were ESBL⁺. The predominant virulence genes found were fimH (100%), iucD (85%) and iha (60%). The strains isolated from pregnant women from Puebla presented a large percentage of genes associated with upper urinary tract infections. PAIs were found in 51% and 68% of the strains from Sonora and Puebla, respectively. All the strains were siderophores producers and 41.5% produced hemolysis. The serotypes found were diverse and belonged to phylogroups A, B2 and C. Conclusion: The UPEC strains from this study are MDR with tendency to XDR or PDR, they can cause upper UTIs and are serotypically and phylogenetically diverse, which supports the need to develop new strategies for UTI treatment in pregnant and non-pregnant Mexican women.

The Pseudomonas aeruginosa genome can change to adapt to different ecological niches. We compared four genomes from a Mexican hospital and 59 genomes from GenBank from different niches, such as urine, sputum, and environmental. The ST analysis showed that high-risk STs (ST235, ST773, and ST27) were present in the genomes of the three niches from GenBank, and the STs of Mexican genomes (ST167, ST2731, and ST549) differed from the GenBank genomes. Phylogenetic analysis showed that the genomes were clustering according to their ST and not their niche. When analyzing the genomic content, we observed that environmental genomes had genes involved in adapting to the environment not found in the clinics and that their mechanisms of resistance were mutations in antibiotic resistance-related genes. In contrast, clinical genomes from GenBank had resistance genes, in mobile/mobilizable genetic elements in the chromosome, except for the Mexican genomes that carried them mostly in plasmids. This was related to the presence of CRISPR-Cas and anti-CRISPR; however, Mexican strains only had plasmids and CRISPR-Cas. bla_OXA-488 (a variant of bla_OXA50) with higher activity against carbapenems was more prevalent in sputum genomes. The virulome analysis showed that exoS was most prevalent in the genomes of urinary samples and exoU and pldA in sputum samples. This study provides evidence regarding the genetic variability among P. aeruginosa isolated from different niches.

Multidrug-resistant bacteria are a growing problem in different environments and hosts, but scarce information exists about their prevalence in reptiles. The aim of this study was to analyze the resistance mechanisms, molecular typing, and plasmid content of cefotaxime-resistant (CTX^R) Escherichia coli isolates recovered from cloacal samples of 71 turtles sheltered in a herpetarium in Mexico. CTX^R-E. coli were recovered in 11 of 71 samples (15.5%), and one isolate/sample was characterized. Extended-spectrum β-lactamase (ESBL)-producing E. coli isolates were detected in four samples (5.6%): two strains carried the bla_CTX-M-2 gene (phylogroup D and ST2732) and two contained the bla_CTX-M-15 gene (phylogroup B1 and lineages ST58 and ST156). The bla_CMY-2 gene was detected by PCR in E. coli isolates of eight samples (9.8%) (one of them also carried bla_CTX-M-2); these isolates were distributed into phylogroups A (n = 1), B1 (n = 6), and D (n = 1) and typed as ST155, ST156, ST2329, and ST2732. Plasmid-mediated quinolone resistance (PMQR) genes were detected in five isolates [aac(6′)Ib-cr, qnrA, qnrB19, and oqxB]. From three to five replicon plasmids were detected among the strains, being IncFIB, IncI1, IncF_rep, and IncK the most prevalent. ESBL or pAmpC genes were transferred by conjugation in four strains, and the bla_CTX-M-15 and bla_CMY-2 genes were localized in IncFIB or IncI1 plasmids by Southern blot hybridization assays. Class 1 and/or class 2 integrons were detected in eight strains with six different structures of gene cassette arrays. Nine pulsed-field gel electrophoresis patterns were found among the 11 studied strains. To our knowledge, this is the first detection of ESBL, CMY-2, PMQR, and mobile determinants of antimicrobial resistance in E. coli of turtle origin, highlighting the potential dissemination of multidrug-resistant bacteria from these animals to other environments and hosts, including humans.