Variation and Characterization of Bacterial Communities Contaminating Two Saunas Operated at 64degrees C and 76degrees C

This study was performed to analyze 6 day-term variations in bacterial communities contaminating the floor of two dry saunas that were operated at 64degrees C (low temp) and 76degrees C (high temp). Bacteria were sampled daily from the saunas for 6 days from Monday to Saturday. Genomic DNA was isolated directly from bacteria-collected cotton swabs. The diversity of the bacterial communities collected from the saunas was analyzed using thermal gradient gel electrophoresis (TGGE). The total numbers of DNA bands separated by TGGE for bacteria collected from the low temp and high temp sauna were 20 and 18, respectively, during the 6 days. Seven of 20 bacteria in the low temp sauna and eight of 18 bacteria in the high temp sauna were detected more than three times over the 6 experimental days. Twelve of the 26 bacterial genera contaminating the saunas were cross detected. Bacteria belonging to the genera Moraxella and Acinetobacter were selectively detected in the low temp sauna, whereas those belonging to Aquaspirillum, Chromobacterium, Aquabacterium, Gulbenkiania, Pelomonas, and Aquitalea were selectively detected in the high temp sauna. Three species of bacteria contaminating both the low and high temp saunas were thermophile or thermoduric. The results indicate that the sauna-contaminating bacteria may have been transferred from outside the saunas by user traffic but did not inhabit the saunas.

Characterization of Bacterial Community Contaminating Floor of A Hot and Dry Sauna

The purpose of this study was to examine profile of bacteria contaminated in a dry sauna. Bacteria sampled from the floor of the dry sauna (75~80degrees C) were separated and identified by using a thermal gradient gel electrophoresis (TGGE) technique, and were cultivated using a defined medium at 50degrees C. Bacteria grown in the defined medium were identified based on 16S-rDNA sequence homology. The band number of DNA separated by TGGE was 15, indicating the species diversity of bacteria contaminating the dry sauna. Seven species of bacteria were successfully cultured on agar plate medium at 50degrees C, which represented a combination of thermophilic and thermoduric bacteria contaminating the dry sauna. The highest limit temperature for growth of the bacterial isolates was generally 50degrees C when cultivated in a defined medium, but was raised to 60degrees C when cultivated in a complex medium. Consequently, the bacteria grown at 50~60degrees C are thermoduric or thermophilic, but others may not be.

Quantitative and Qualitative Estimation of Bacteria Contaminating Human Hairs

Human hairs have been known to be easily contaminated with microorganisms. This study was performed in order to measure what bacterial species and how much microorganisms contaminate human hairs in specific place. Virgin human hairs were left at 6 positions in inside corner and beside window in a laboratory for 7 days. The number of viable bacterial cells, which were determined by most probable number method, contaminating the human hairs was measured at a maximum of 10(6)/g hair and a minimum of 10(3)/g hair in inside corner and maximum of 10(6)/g hair and a minimum of 10(3)/g hair beside window. The bacterial cells-contaminating human hairs were observed via fluorescence light microscopy after 4',6-diamino-2-phenylindole (DAPI) staining. The bacterial community contaminating human hairs was analyzed via the thermal gradient gel electrophoresis (TGGE) technique, based on the diversity of the 16S-rDNA variable region. In total, approximately 20 bacterial species were detected from 12 groups of hair samples. In this study, general experimental methods-fluorescence staining, TGGE and MPN-were combined to develop new method for observation and estimation of bacteria contaminating human hairs.

Quantitative and Qualitative Estimation of Bacteria Contaminating Human Hairs

Human hairs have been known to be easily contaminated with microorganisms. This study was performed in order to measure what bacterial species and how much microorganisms contaminate human hairs in specific place. Virgin human hairs were left at 6 positions in inside corner and beside window in a laboratory for 7 days. The number of viable bacterial cells, which were determined by most probable number method, contaminating the human hairs was measured at a maximum of 10(6)/g hair and a minimum of 10(3)/g hair in inside corner and maximum of 10(6)/g hair and a minimum of 10(3)/g hair beside window. The bacterial cells-contaminating human hairs were observed via fluorescence light microscopy after 4',6-diamino-2-phenylindole (DAPI) staining. The bacterial community contaminating human hairs was analyzed via the thermal gradient gel electrophoresis (TGGE) technique, based on the diversity of the 16S-rDNA variable region. In total, approximately 20 bacterial species were detected from 12 groups of hair samples. In this study, general experimental methods-fluorescence staining, TGGE and MPN-were combined to develop new method for observation and estimation of bacteria contaminating human hairs.