Monitoring of antibiotic resistance in bacteria isolated from laboratory animals / 한국실험동물학회지

The drug resistance of microorganisms isolated from laboratory animals never treated with antibiotics is being reported consistently, while the number of laboratory animals used in medicine, pharmacy, veterinary medicine, agriculture, nutrition, and environmental and health science has increased rapidly in Korea. Therefore, this study examined the development of antimicrobial resistance in bacteria isolated from laboratory animals bred in Korea. A total of 443 isolates (7 species) containing 5 Sphingomonas paucimobilis, 206 Escherichia coli, 60 Staphylococcus aureus, 15 Staphylococcus epidermidis, 77 Enterococcus faecalis, 27 Citrobacter freundii, 35 Acinetobacter baumannii were collected from the nose, intestine, bronchus and reproductive organs of ICR mice and SD rats. Of these species, Acinetobacter baumannii and Enterococcus faecalis showed significant antimicrobial resistance according to the minimum inhibition concentration (MIC) in E-test. In case of Acinetobacter baumannii, several isolates showed MIC values 16-128 microg/mL for cefazolin and cefoxitin, and higher resistance (128-512 microg/mL) to nitrofurantoin than that of standard type. Resistance to cefazolin, cefoxitin and nitrofurantoin was detected in 17.14, 20.00, and 8.57% of the Acinetobacter baumannii isolates, respectively. In addition, 44.1% of the Enterococcus faecalis isolates collected from the laboratory animals were resistant to oxacillin concentration of 16-32 microg/mL range, while MIC value of standard type was below oxacillin concentration of 6 microg/mL. These results suggest that in rodent species of laboratory animals, Acinetobacter baumannii are resistance to cefazolin, cefoxitin and nitrofurantoin, whereas those of Enterococcus faecalis were resistance to oxacillin.

Investigation of the Bovine Leukemia Virus Proviral DNA in Human Leukemias and Lung cancers in Korea

The bovine leukemia virus (BLV) is the causative agent of enzootic bovine leucosis. This study investigated the presence of the BLV in leukemia (179 acute lymphoblastic leukemia, 292 acute myeloid leukemia and 46 chronic myelogenous leukemia cases) and 162 lung cancer patients (139 adenocarcinoma, 23 squamous cell carcinoma) to determine if the BLV is a causative organism of leukemia and lung cancer in Koreans. A BLV infection was confirmed in human cells by PCR using a BLV-8 primer combination. All 517 cases of human leukemia and 162 lung cancer were negative for a PCR of the BLV proviral DNA. In conclusion, although meat has been imported from BLV endemic areas, the BLV infection does not appear to be the cause of human leukemia or lung cancer in Koreans. These results can be used as a control for further studies on the BLV in Koreans.