Epidemiologic and molecular characterization of β-lactamase-producing multidrug-resistant uropathogenic Escherichia coli isolated from asymptomatic hospitalized patients

Occurrence of Imipenem-Resistant Uropathogenic Escherichia coli in Pregnant Women: An Insight into Their Virulence Profile and Clonal Structure

Uropathogenic Escherichia coli (UPEC) is the predominant pathogen in Urinary Tract Infection (UTI) in pregnant and non-pregnant women. Limited studies were initiated to explore UPEC from pregnant women with respect to imipenem resistance, pathogenicity, and their clonal lineage. In this study, imipenem resistance, phylogenetic background, virulence-associated genes, and clonal characteristics in UPECs isolated from pregnant and non-pregnant cohorts were investigated. E. coli was identified biochemically from urine culture-positive samples from pregnant and non-pregnant women. Carbapenem (meropenem, ertapenem, imipenem) susceptibility was determined by Kirby-Bauer disk diffusion test. The pathogenic determinants were identified by PCR. MEGA 11 was used to interpret clonal lineages from MLST. GraphPad Prism 8.0 and SPSS 26.0 were used for statistical interpretation. Results indicated highest resistance against imipenem compared to meropenem and ertapenem in UPECs isolated from pregnant (UPECp; 63.89%) and non-pregnant (UPECnp; 87.88%) women. Although phylogroup E was predominant in both imipenem-resistant isolates, acquisition of virulence factors was higher among UPECnp than UPECp. Akin to this observation, the presence of PAI III536 and PAI IV536 was statistically significant (p < 0.05) in the former. MLST analysis revealed similar clonal lineages between UPECnp and UPECp, which showed an overall occurrence of ST405 followed by ST101, ST410, ST131, and ST1195 in UPECnp and ST167 in UPECp, respectively, with frequent occurrence of CC131, CC405. Therefore, imipenem-resistant UPECp although discrete with respect to their virulence determinants when compared to UPECnp shared similar STs and CCs, which implied common evolutionary history. Thus, empiric treatment must be restricted in UTIs to especially protect maternal and fetal health.

High Frequency of Antibiotic Resistance Genes (ARGs) in the Lerma River Basin, Mexico

The spread of beta-lactamase-producing bacteria is of great concern and the environment has been found to be a main source of contamination. Herein, it was proposed to determine the frequency of antimicrobial-resistant-Gram-negative bacteria throughout the Lerma River basin using phenotypic and molecular methods. Resistant bacteria were isolated with chromogenic media and antimicrobial susceptibility tests were used to characterize their resistance. ARGs for beta-lactams, aminoglycosides, and quinolones were detected by PCR. Species were identified by Sanger sequencing the 16S rRNA gene and the representative genomes of MDR strains were sequenced by NGS. A high variation in the number of isolates was observed in the 20 sampled sites, while observing a low diversity among the resistant bacteria. Of the 12 identified bacterial groups, C. freundii, E. coli, and S. marcescens were more predominant. A high frequency of resistance to beta-lactams, quinolones, and aminoglycosides was evidenced, where the bla_CTX,qnrB, qnrS y, and aac(6')lb-cr genes were the most prevalent. C. freundii showed the highest frequency of MDR strains. Whole genome sequencing revealed that S. marcescens and K. pneumoniae showed a high number of shared virulence and antimicrobial resistance genes, while E. coli showed the highest number of unique genes. The contamination of the Lerma River with MDR strains carrying various ARGs should raise awareness among environmental authorities to assess the risks and regulations regarding the optimal hygienic and sanitary conditions for this important river that supports economic activities in the different communities in Mexico.

Screening and Characterization of Multidrug-Resistant Enterobacterales among Hospitalized Patients in the African Archipelago of Cape Verde

This study aimed to investigate, for the first time, the occurrence and characteristics of extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacterales in Cape Verde. A total of 98 inpatients hospitalized at Hospital Universitário Agostinho Neto were screened for rectal colonization. All ESBL- and carbapenemase-producing isolates were tested for antimicrobial susceptibility and characterized by multilocus sequence typing. Mating-out assay followed by PCR-based replicon typing were performed to characterize the plasmids harboring carbapenemase encoding genes. A large proportion of patients carried ESBL- or carbapenemase-producing Enterobacterales (56% and 6%, respectively). Among 93 ESBL-producing isolates, there were mainly Klebsiella pneumoniae (58%) and Escherichia coli (37%). Five different ESBLs were detected, with CTX-M-15 being highly predominant (92%). Six carbapenemase-producing isolates (five E. coli and one K. pneumoniae) were recovered, and all of the OXA-48-like type (four OXA-181, one OXA-48, and one OXA-244). The bla_OXA-48 gene was located on an IncFI-type plasmid, the bla_OXA-181 gene on IncFI or IncX3 plasmids, and the bla_OXA-244 gene was found to be chromosomally located. The five carbapenemase-producing E. coli isolates belonged to five distinct sequence types. This study overall showed a very high prevalence of ESBL-producing Enterobacterales, as well as the emergence of carbapenemase producers in this hospital.