Infective agents are abundant in hospitals, and so medical staff members are often exposed to them. Although previous studies have highlighted the role played by the nasal flora of medical staff in the development of nosocomial infections, few studies have specifically investigated this issue. Six volunteer medical staff members, who worked at Nihon University Hospital at Matsudo, participated in this study. Nasal samples were obtained from the medical staff, and then the samples were cultured and evaluated using routine bacteriological study methods. Staphylococci were detected in the nasal samples of all of the medical staff. Staphylococcus epidermidis was the predominant species in their nasal cavities（71.3％） . None of the medical staff had been infected with methicillin-resistant Staphylococcus aureus（MRSA） , but four of six staff members possessed methicillinresistant coagulase-negative staphylococci（MR-CNS） .Medical staff members are both at risk of infection and also a potential source of nosocomial pathogens such as methicillin-resistant staphylococci. As a preventive measure against nosocomial infection, it might be necessary to continuously investigate the frequency of methicillin-resistant staphylococci in the nasal cavities of medical staff.

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Rothia dentocariosa and Rothia mucilaginosa, which are opportunistic pathogens that are capable of causing serious infections, inhabit the oral cavity. However, there is no suitable method for assessing the prevalence of Rothia species in the oral cavity. In this study, four polymerase chain reaction(PCR)primers were designed based on partial sequences of the 16S rDNA genes of the abovementioned oral Rothia species. These primers react to the oral Rothia species and did not react to other Rothia species except Rothia aeria. Moreover, representative non-Rothia oral bacteria displayed negative reactions to these primers.These results indicate that these primers are useful for identifying R. dentocariosa and R. mucilaginosa. We also developed a simple multiplex PCR procedure involving the two primer pairs designed in the present study as a rapid and reliable method of identifying known oral Rothia species.