Isolation and Identification of Multidrug-Resistant Clones from the Hospital Environment.

Global dispersion, hospital outbreaks, and lineage relationships between emerging antibiotic-resistant strains such as are of public health interest. This study aimed to isolate and identify clones from third-level healthcare hospitals in Mexico to establish their multidrug-resistant phenotype, phylogeny, and prevalence. Biological and abiotic surface samples were used to isolate strains and to test their antibiotic susceptibility to classify them. The housekeeping genes: , , , , , , and were used for multilocus sequence typing (MLST). Phylogenetic networks were constructed with 48 strains. Isolated strains (93) were mainly from urine and blood, 96% were resistant to ampicillin as expected, 60% were extended-spectrum β-lactamases (ESBL), 98% were susceptible to ertapenem and meropenem and 99% were susceptible to imipenem, 46% were multi-drug resistant (MDR), 17% were extensively-drug resistant (XDR), 1% were pan-drug resistant (PDR), and 36% were not classified. The , , and genes were the most variable, and the gene showed positive selection. The most prevalent sequence types (STs) were ST551 (six clones), ST405 (six clones), ST1088 (four clones), ST25 (four clones), ST392 (three clones), and ST36 (two clones). ST706 was PDR, and ST1088 clones were MDR; neither of these STs has been reported in Mexico. The strains analyzed were from different hospitals and locations; thus, it is important to maintain antibiotic surveillance and avoid clone dissemination to prevent outbreaks, adaptation to antibiotics, and the transmission of antibiotic resistance.