High prevalence of MDR gram-negative bacteria in feces of healthy blood donors in Mexico.

During the initial stage of a study to recruit universal intestinal microbiota donors in Mexico City, we found multiple "healthy" subjects that colonized with MDRO (Multidrug-resistant organisms). We aimed to describe clinical and demographic characteristics of these individuals. This was a prospective observational study. Participants were consecutively recruited among blood donors. A fecal sample was collected from each subject and analyzed at the same day in search of MDRO through chromographic culture media and, if growth observed, later confirmed by MALDI-TOF and susceptibility testing in Vitek 2 system. From July 2018 to March 2019, 85 individuals were screened for fecal colonization. Median age was 35 years (IQR 27-46 years), and 48/85 (56.4%) were males. Seventy-two (84.7%) subjects harbored at least one MDRO. ESBL-producing microorganisms were found in 72/85 (84.3%) subjects, and E. coli was the most frequent (63/85, 74.1%). Four samples (2 E. coli, 2 P. aeruginosa, 2.4% each) harbored carbapenem-resistant Enterobacteriaceae (CRE), together with an ESBL-producing microorganism. Antibiotic use (p = 0.06) and PPIs or H2-blockers intake (p = 0.03) were more common in the colonized subjects during the previous 6-month period. We report a high incidence of enteric colonization of healthy subjects with MDRO, a condition that may be related to antibiotics or PPIs/H2-blockers consumption. This surprisingly high MDRO colonization rate in potential FMT donors emphasizes the need for careful screening of donors to avoid possible transmission to FMT recipients.