Carbapenem-resistant Enterobacteriaceae (CRE) have spread epidemically in the United States and Europe among hospitalized patients. In Japan, CRE infection is a category V infectious disease under the Infectious Disease Control Law from September 19, 2014. CRE includes Klebsiella spp., Citrobacter spp., and Enterobacter spp., which are the coliforms highly detected from foods. In this study, we tried to detect β-lactamase (especially carbapenemase) producing gram negative rods among the swabs from food processing plants or the foods retailed in Osaka City from April, 2008 to January, 2013. We also investigated the antimicrobial susceptibility test in these isolates, and tried to search for drug resistant genes among these strains. Consequently, only one (Pseudomonas fluorescens) isolate among 114 strains was resistant to meropenem, but Pseudomonas fluorescens was not carbapenemase-producing Enterobacteriaceae (CPE). The prevalence of CPE among foods and its surrounding environment is low. Although 6 of 10 isolates which are resistant to cefoxitin are thought to be AmpC β-lactamase producing bacteria, these are intrinsic resistance by chromosomal AmpC β-lactamase. Two isolates of Rahnella aquatilis were possessed CTX-M type extended spectrum β-lactamase (ESBL) gene which encodes chromosomal RAHN-2 gene.
The identification of 84 strains of NBRC strains and yeasts isolated from foods and other products were examined by DNA sequence analysis and the results were compared with commercially available identification Kit (API 20C AUX). In the DNA sequence analysis, all 84 yeast strains tested were possible to identify by two regions of D2 and ITS1 in the rDNA. Concordance rate from comparison of results of API 20C AUX and DNA sequence analysis were 57.1% at the species level, 82.1% at the genus level. In addition, the results of API 20C AUX and DNA sequence analysis had a tendency to agree at the species level when identification probability of API 20C AUX were more than 90%. The part of strains of Candida intermedia /C. pseudointermedia identified by DNA sequence analysis were identified as Trichosporon mucoides with more than 90% identification probability by API 20C AUX. As the results, we were able to identify the yeasts by API 20C AUX when combining the identification probabilities and rDNA sequence analysis.