Non-O157 Shiga toxin-producing Escherichia coli-A poorly appreciated enteric pathogen: Systematic review.

Non-O157 strains of Shiga toxin-producing Escherichia coli (STEC) are more common causes of acute diarrhea than the better-known O157 strains and have the potential for large outbreaks. This systematic review of the literature identified 129 serogroups as well as 262 different O and H antigen combinations of STEC in cases of epidemic and sporadic disease worldwide. Excluding the results from a single large outbreak of STEC O104:H4 in Germany and France in 2011, the reported frequency of dysenteric illness in patients was 26% (119 of 464) for epidemic disease and 25% (646 of 2588) for sporadic cases. Hemolytic uremic syndrome was identified in 14% of epidemic disease cases and 9% of sporadic illness cases. With the increasing use of PCR-based diagnostics, STEC strain identification may not be possible. Rapid diagnostics are needed for STEC infections to aid the clinician while allowing epidemiologists the opportunity to identify outbreaks and to trace the source of infection.

Stability and efficacy of frozen and lyophilized fecal microbiota transplant (FMT) product in a mouse model of Clostridium difficile infection (CDI).

Freezing donor fecal microbiota has simplified fecal microbiota transplantation (FMT) in the treatment of recurrent C. difficile infection (CDI). However, the optimal storage time for the frozen FMT products remains unknown. Using an established murine model of CDI, stability and efficacy of frozen and lyophilized FMT product was studied at time points from 2 months to 15 months. DNA was extracted from fecal samples from the mice with identification of specific bacterial species by real-time quantitative PCR (qPCR). FMT product stability and efficacy were measured by occurrence of diarrhea in the challenged mice together with stability of the microbiota composition. The results were analyzed and compared by SAS statistical software. All mice treated with only C. difficile developed diarrhea within 72 h. Mice treated with frozen (n = 5/group), lyophilized (n = 5/group) products stored for ≤ 7-month or fresh FMT product (n = 22) were protected from post C. difficile challenge diarrhea. There was no difference between frozen and lyophilized products (n = 5/group) stored for ≤ 7 months 95% CI 1.00 (0.38-2.64) and 1.00 (0.38-2.64), respectively. Prevention if CDI by frozen and lyophilized product was not different for storage of 9-, 11- and 15-months. qPCR results demonstrated there were no significant quantitative change in Bacteroides and Clostridium species during any of the storage times (P > 0.05). In the present study, frozen and lyophilized FMT products were stored up to 7 months without losing microbiota composition and therapeutic efficacy. The animal model described may be useful to study stability of human microbiota designed for FMT.