Methicillin-resistant Staphylococcus aureus (MRSA), regarded as a tenacious pathogen in the hospital, has recently become increasingly prevalent as a community pathogen. We evaluated the prevalence and characteristics of methicillin-resistant staphylococci in the Japanese community by testing nasal samples of 818 children of five day care centers and two kindergartens in three districts. We found that methicillin-resistant staphylococci are already prevalent among healthy children. Among 818 children, 35 children (4.3%) carried MRSA and 231 children (28.2%) carried methicillin-resistant coagulase-negative staphylococci (MRC-NS). The types of staphylococcal cassette chromosome mec (SCCmec) found among 44 MRSA isolates were as follows: type IIa, 11 isolates; type IIb, 19 isolates; and type IV, 14 isolates. The type IIb SCCmec element was a new SCCmec element found in this study. Eleven (25%) strains which belonged to clonal complex 5 (CC5) carried type IIa SCCmec, and they produced type 2 coagulase and toxic shock syndrome toxin 1. They were indistinguishable from health care-associated MRSA (H-MRSA) strains in Japan, represented by strain N315. On the other hand, 33 (75%) strains, most of which belonged to CC78 or CC91, carried small SCCmec elements, such as type IIb or type IV, and they produced type 1 or type 3 coagulase and exfoliative toxin. The data indicated that MRSA clones distinct from H-MRSA have disseminated in healthy children. The fact that MRC-NS strains were prevalent in the community suggested that they might serve as a reservoir for the SCCmec element carried by MRSA strains disseminated in the community.

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Determination of the serum level of intestinal fatty acid-binding protein has been used to detect rat intestinal ischemia following ligation or 30-min occlusion of the superior mesenteric artery. The normal values were under the minimal detectable level of less than 2 ng/ml in all the 10 rats. The serum fatty acid-binding protein level increased rapidly, to 340.7 +/- 54.6, 438.5 +/- 40.1, 388.1 +/- 37.4, and 292.2 +/- 95.7 ng/ml (P less than 0.01) at 1, 2, 4, and 8 hr after ligation, respectively. It also increased, to 347.2 +/- 127.7 ng/ml (P less than 0.01) at 1 hr, after a 30-min transient occlusion and then returned to a normal level. Histological studies showed destruction of the villi, disappearance of the mucosa, and transmural necrosis with the progress of time after ligation, while no remarkable morphological change was observed following 30-min transient occlusion. These observations strongly suggest that the intestinal fatty acid-binding protein is a useful biochemical marker for intestinal ischemia, particularly in the early reversible phase.

A simple and rapid slide latex agglutination assay was developed to detect penicillin-binding protein 2' (PBP2') from isolates of staphylococi. PBP2' present in the membranes of methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase negative staphylococci (MRCNS) was rapidly extracted by alkaline treatment and,by combining with a slide agglutination reaction using latex particles sensitized with monoclonal antibodies raised against it, PBP2' could be detected from a single loopful of cells taken from agar plates not containing beta-lactum antibiotics within 15 min. In a study of clinical isolates previously characterized as either MRSA or methicillin-susceptible Staphylococcus aureus (MSSA) by antibiotic susceptibility testing, 231 specimens of 232 MRSA were PBP2' positive by latex agglutination, and the 87 specimens of MSSA were all negative. One specimen identified as MRSA by susceptibility testing but PBP2' negative by latex agglutination was confirmed as mecA gene negative by PCR. This simple and rapid slide latex reagent should be useful in clinical diagnostics.