Isolation and Characterization of Staphylococcus aureus from Raw Fish and Meat

Abstract

From May, 1987 to May, 1989, raw fish and meat samples obtained from retail shops in Hyogo Prefecture were examined for the contamination with Staphylococcus aureus. The isolates were tested for some biological characteristics and enterotoxigenicity. S. aureus was isolated from 148 (44.7%) of 331 fish and 125 (59.5%) of 210 meat samples. It was found in 19 (25.3%) of 75 scad, 35 (34.7%) of 101 sardine, nine (28.1%) of 32 mackerel, 43 (71.7%) of 60 saury, 39 (78.0%) of 50 squid, three (23.1%) of 13 oyster, 102 (92.7%) of 110 chicken, 13 (26.0%) of 50 pork, and 10 (20.0%) of 50 beef samples. Two hundred and thirty (82.1%) of 280 fish isolates and 119 (95.2%) of 125 meat isolates were biotyped. Most of them were biotype B or C. Two hundred and two (72.1%) of the 280 fish isolates and 50 (40.0%) of the 125 meat isolates were typable with the human phages. Most of the fish isolates belonged to mixed groups, group III and group II. Most meat isolates belonged to group III. Eighty (94.1%) of 85 fish isolates and 44 (64.7%) of 68 meat isolates were typable with the eight coagulase-typing antisera. The most predominant type among the fish isolates was type VII, followed by types III, II, I and VIII; that among the meat isolates was type VII, followed by types VIII, III, VI, II and V. Nineteen (22.4%) of the 85 fish isolates and 38 (30.4%) of the 125 meat isolates produced enterotoxin. The most predominant enterotoxin type produced by the fish isolates was B, followed-by A, AB and AD; that produced by the meat isolates was B, followed by C, A and AB. Forty-seven (55.3%) of the 85 fish isolates and 39 (31.2%) of the 125 meat isolates were resistant to one or more of six antibiotics. The most predominant resistance pattern among the fish isolates were PC; that of the meat isolates were LCM/EM and PC.