Role of wild birds as carriers of multi-drug resistant Escherichia coli and Escherichia vulneris

Emergence and distribution of multi-drug resistant (MDR) bacteria in environments pose a risk to human and animal health. A total of 82 isolates of Escherichia spp. were recovered from cloacal swabs of migrating and non-migrating wild birds. All bacterial isolates were identified and characterized morphologically and biochemically. 72% and 50% of isolates recovered from non-migrating and migrating birds, respectively, showed positive congo red dye binding (a virulence factor). Also, hemolysin production (a virulence factor) was showed in 8% of isolates recovered from non-migrating birds and 75% of isolates recovered from migrating birds. All isolates recovered from non-migrating birds were found resistant to Oxacillin while all isolates recovered from migrating birds demonstrated resistance to Oxacillin, Chloramphenicol, Oxytetracycline and Lincomycin. Some bacterial isolates recovered from non-migrating birds and migrating birds exhibited MDR phenotype. The MDR isolates were further characterized by API 20E and 16S rRNA as E. coli and E. vulneris. MDR Escherichia isolates contain ~1-5 plasmids of high-molecular weights. Accordingly, wild birds could create a potential threat to human and animal health by transmitting MDR bacteria to water streams and other environmental sources through their faecal residues, and to remote regions by migration.

Biochemical Characteristics and Antimicrobial Susceptibility Patterns of Vibrio vulnificus Isolated from the Environment of Korea in 2001

Vibrio vulnificus is a pathogen causing two types of severe illness, septicemia and wound infections, and is continually detected in marine environments. To investigate the biochemical characteristics and the antimicrobial susceptibility of V. vulnificus isolated from environment of Korea in 2001, the API 20E kit test, PCR, and antibiotic disk diffusion method were performed. A total of 210 V. vulnificus strains was isolated from seawater, shell-fish, sediments, coastal water, aquarium water, sewage, and others. All of the isolates could be divided into 15 groups on the basis of their API 20E profiles, and were positive in Indole test. Only 173 isolates (82.4%) were positive by the PCR amplifying the cytolysinhemolysin gene. Almost all isolates were susceptible to chloramphenicol (99.5%), tetracycline (90.0%), ciprofloxacin (92.4%), trimethoprim/sulfamethoxazole (89.0%), nalidixic acid (87.6%). Some isolates were resistant to cephalothin (57.6%), amikacin (33.3%), cefoxitin (31.9%). One hundred and forty three isolates (68.1%) were resistant to one or more antimicrobial agents. These results show that V. vulnificus environmental isolates possessed various biochemical characteristics, and some isolates were not detected of the cytolysin-hemolysin gene by PCR, and a part of isolates were resistant to multiple antibiotics.

Microplate Identification System of Enterobacteriaceae / 대한임상미생물학회지

BACKGROUND: To access the accuracy and clinical usefulness of microplate identification (ID) system for the identification of Enterobacteriaceae, we compared microplate ID system with API 20E(bioMerieux, Etoile, France). METHODS: Ninety-two cultures of Enterobacteriaceae and one isolate of Aeromonas species were simultaneously identified by microplate ID system and the API 20E. Twenty biochemical tests used in microplate ID system were lactose, sucrose, and H2S in Kligler's iron agar media; indole, sucrose, raffinose, arabinose, trehalose, adonitol, dulcitol, sorbitol, cellibiose, methy-red, phenylalanine deaminase, ornithine decarboxylase, lysine decarboxylase, arginine dihydrolase, urease, and citrate in microplate; and oxidase test. The identification was obtained by considering percent likelihood(% ID), modal frequency and ID score method. RESULTS: Among the 92 cultures of Enterobacteriaceae and one isolate of Aeromonas species, agreement rate of identification according to the % ID between microplate ID system and API 20E were 90.3% to the species level and 97.8% to the genus level. CONCLUSIONS: For the identification of clinical Enterobacteriaceae isolates, the microplate ID system compares favorably with API 20E in identification accuracy and have the advantage of costsaving and easy to use.