Predominance of FQR1 NAP1/RT027 Clostridioides difficile Among Mexican Children and Adult Patients, and its Resistance to Eleven Antibiotics

Aims

Clostridioides difficile is a major cause of antibiotic-associated diarrhea. This study investigated the diversity, clonality, and antimicrobial resistance of C. difficile isolates from Mexican children and adults with diarrhea.

Methods

Between 2014 and 2016, we isolated 37 C. difficile strains in three hospitals in Mexico City. C. difficile strains were typed by PCR-ribotyping and pulsed-field gel electrophoresis (PFGE). Antimicrobial susceptibility to eleven antibiotics was determined. Whole-genome sequencing (WGS) was used to investigate the presence of antimicrobial resistance genes (ARG) and perform a pangenome analysis of 53 genomes from Mexico and 137 publicly available C. difficile genomes.

Results

Toxigenic strains comprised six isolates from children and 31 from adults. While NAP1/RT027 isolates were found in three children, they were predominant in adults (n = 31, 90.3 %) and showed the 1058 and 008 PFGE macrorestriction patterns. All isolates were susceptible to vancomycin and metronidazole but resistant to ciprofloxacin, and over 90 % of the isolates were resistant to linezolid and carried cfr(E). The pangenome of these isolates contained 4,852 genes, of which 3,455 (81.2 %) were categorized as core genes and 801 (18.8 %) as accessory genes. In addition, our isolates demonstrated a close relationship with strains from the United States, Canada, and France.

Conclusions

Our work provides, for the first time, genomic insights into C. difficile strains present in Mexico. In our hospital setting, the predominant strains were primarily NAP1/RT027 and exhibited resistance to linezolid, a pattern observed in both pediatric and adult populations. This unique combination of characteristics has not been previously reported in Latin America.