ABSTRACTEmerging multidrug-resistant (MDR) Gram-negative bacilli (GNB), includingEscherichia colisequence type 131 (ST131) and its resistance-associatedH30 subclone, constitute an ever-growing public health threat. Their reservoirs and transmission pathways are incompletely defined. To assess diarrheal stools as a potential reservoir for ST131-H30 and other MDR GNB, we cultured 100 clinical stool samples from a Veterans Affairs Medical Center clinical laboratory (October to December 2011) for fluoroquinolone- and extended-spectrum cephalosporin (ESC)-resistantE. coliand other GNB, plus totalE. coli. We then characterized selected resistant and susceptibleE. coliisolates by clonal group, phylogenetic group, virulence genotype, and pulsotype and screened all isolates for antimicrobial resistance. Overall, 79 of 100 stool samples yielded GNB (52E. coli; 48 other GNB). Fifteen samples yielded fluoroquinolone-resistantE. coli(10 were ST131, of which 9 wereH30), 6 yielded ESC-resistantE. coli(2 were ST131, both non-H30), and 31 yielded susceptibleE. coli(1 was ST131, non-H30), for 13 total ST131-positive samples. Fourteen non-E. coliGNB were ESC resistant, and three were fluoroquinolone resistant. Regardless of species, almost half (46%) of the fluoroquinolone-resistant and/or ESC-resistant non-E. coliGNB were resistant to at least three drug classes. Fecal ST131 isolates closely resembled reference clinical ST131 isolates according to virulence genotypes and pulsed-field gel electrophoresis (PFGE) profiles. Thus, a substantial minority (30%) of veterans with diarrhea who undergo stool testing excrete antibiotic-resistant GNB, includingE. coliST131. Consequently, diarrhea may pose transmission risks for more than just diarrheal pathogens and may help disseminate clinically relevant ST131 strains and other MDR GNB within hospitals and the community.
Initial Assessment of the Molecular Epidemiology ofblaNDM-1in Colombia
