[Biological properties and drug susceptibility of verotoxin-producing Escherichia coli (VTEC) isolated from healthy goats in Okinawa Prefecture].

ABSTRACT

Fecal samples from 116 healthy goats out of 25 randomly selected farms were examined for verotoxin-producing Escherichia coli (VTEC) during 1996 and 1998 in Okinawa Prefecture. VTECs were detected 204 (15.0%) from 1,361 E. coli strains, 36 (31.0%) goats out of 13 (52.0%) farms. Randomly selected 88 strains were further characterized according to VT types, serotypes, virulence markers, biochemical properties and drug susceptibility. VT types were classified as VT1 (46.6%), VT2 (6.8%), and VT1/VT2 (46.6%) by means of reversed latex agglutination test. The VTEC belonged to 18 different O serogroups O1, O6, O22, O27, O48, O75, O76, O77, O78, O82, O91, O103, O111, O123, O125, O128, O146, and O158. Serotypes O91H- (13 strains), O27H- (10 strains), O22H19 (6 strains) are considered to be predominant, whereas O serotypes O157 and O26 were not isolated. eaeA gene was detected only in 5 strains (5.7%)O103H2 and O111H-, in contrast, hlyA gene was found frequent in 45 strains (51.1%) belong to various O serogroups, except for O146 (8 strains). On the basis of 20 biochemical features in all isolates, characteristic patterns were divided into 14 distinct types47 strains (57.3%) were classified as one type. The VTECs examined were resistant to streptomycin (26.7%), ampicillin (12.2%), kanamycin (8.9%), oxytetracyline (8.9%), and oxolinic acid (3.3%), respectively. The current results indicate that goats harbored VTEC at high frequencies and may be a potential reservoir of human VTEC infection.