Comparative chracterization of Staphylococcus aureus isolates from throats and noses of healthy volunteers.

Staphylococcus aureus isolates in 2001 from the nose and the throat of an adult population were characterized for their incidence and type. The incidence was 51%, present in 80 out of 157 individuals examined, consisting of 34 nasal carriers, 24 throat carriers, and 22 who carried the isolates in both the nose and throat. Among these isolates, 2 and 5 from the nose and the throat, respectively, were identified as methicillin-resistant S. aureus. S. aureus from the nose and throat of the same individuals were characterized for identification. Examination of their phenotypes revealed that in 11 individuals the clone of S. aureus in the throat was different from the nasal clone. These results suggested that staphylococcal flora in the nose and the throat were independently formed, and that attention should also be directed to the carriers of S. aureus in the throat for the control of nosocomial infection.

Staphylococcus aureus isolated from hospital staff: a comparative study of Laos and Japan.

Staphylococcus aureus isolated from hospital staff (nurses and doctors) in Laos were characterized for future reference and for comparison with organisms found in Okinawa, Japan. No methicillin-resistant S. aureus (MRSA), among 38 isolates examined, was found in Laos, but 16 of 36 Japanese isolates (44%) were identified as MRSA. The minimum inhibitory concentrations (MICs) of ampicillin and tetracycline against Lao isolates were definitely higher than those against Japanese isolates. The MIC(80) of tetracycline was 50 microg/ml and 0.4 microg/ml in Lao and Japanese isolates, respectively. There was no marked difference in the production of enterotoxin by S. aureus strains in the two countries. Toxic shock syndrome toxin-1 was produced by only 1 of 38 Lao isolates but by 5 of 36 Japanese isolates. Coagulase types varied greatly, but about 50% of the isolates in both countries produced untypable coagulase. Since the interaction of Laotians with foreigners has increased rapidly in recent years, the careful monitoring of drug-resistant pathogens is required.

Enteroaggregative Escherichia coli: incidence in Japan and usefulness of the clump-formation test.

The usefulness of the clump-formation test described by Albert et al. for identifying enteroaggregative Escherichia coli (EAggEC) and the incidence of EAggEC in Japan were studied. One hundred and seventy strains of E. coli agglutinated with enteropathogenic E. coli diagnostic antisera were collected from a variety of districts in Japan. All isolates were from diarrheal stools. EAggEC was identified on the basis of the presence of the aggR gene accompanied by aggregative adhesion to HEp-2 cells. After 24 strains carrying eaeA, elt, est, stx-1, stx-2, or ipaH genes were eliminated, the remaining 145 strains were examined for adhesion to Hep-2 cells, the presence of the aggRgene, and clump formation on the surface of Muller-Hinton broth. aggR was detected in 10 strains, and 9 of them displayed aggregative adhesion to HEp-2 cells. Seven strains produced marked clumps and 22 showed moderate clump formation. The sensitivity and specificity of the clump-formation test for detecting EAggEC were each about 90%, and they varied slightly depending on the stringency of evaluation for the degree of clump formation. From these results, we conclude that the incidence of EAggEC cannot be ignored as a possible cause of diarrheal disease in Japan, and we strongly recommend the clump-formation test for detecting EAggEC.