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A new Vibrio cholerae serogroup 0139 strain of unknown origin recently emerged in India and Bangladesh, causing a major outbreak of cholera. The genetic relationship between this epidemic strain and the 01 strain responsible for the 7th pandemic ofcholera was studied by analyzing the DNA polymorphism of V. cholerae by pulsed-field gel electrophoresis and arbitrarily primed polymerase chain reaction. The restriction patterns of the reference strain 0139 Bengal and 10 wild 0139 strains isolated early in the Indian outbreak strikingly resemble that of the pandemic 01 strain of V. cholerae El Tor, thus suggesting a close genetic relationship among these strains. This similarity contrasts with the genetic heterogeneity of sporadic non-O1 strains isolated in various parts of the world. Study results strongly suggest that the new epidemic 0139 strain is closely related to and might be derived from the pandemic 01 strain of V. cholerae .

Staphylococcus aureuscapsular polysaccharide type 5 (CP5) expression was investigated in lung tissue and nasal polyps of two cystic fibrosis (CF) patients, in rats, and in vitro using ELISA and IFA. In CF tissues, S. aureus expressed protein A and teichoic acid but only 1%–5% of cells expressed CP5. When rats were challenged with CP5-positive S. aureus in the granuloma pouch model, only 1%–5%of CP5-positive cells were detectable in pouch exudates. CF and pouch isolates, however, reexpressed CP5 (70%–90% of cells) when grown in vitro with air. Addition of 1% CO2 to air or to O2/N2 gas mixtures reduced CP5 expression significantly (P<.001) in a dose-dependent manner (6%–1% CP5-positive cells). The results show that S. aureus does not produce CP5 in CF airways and in rat granuloma pouches and that CO2 is an environmental signal that regulates CP5 expression.