title: Detection of viable and viable nonculturable Vibrio cholerae O1 through cultures and immunofluorescence in the Tucumán rivers, Argentina.
abstract: Vibrio cholerae has been sporadically isolated from rivers in Tucumán, Argentina, since the outbreak in 1991. The aim of this study was to determine the environmental reservoir of the bacterium in these rivers, assessing the presence of Vibrio cholerae non-O1 and O1 (the latter both in its viable culturable and non culturable state) and its relationship to environmental physicochemical variables. 18 water samplings were collected in the Salí River (in Canal Norte and Banda) and the Lules River between 2003 and 2005. Physical-chemical measurements (pH, water temperature, electrical conductivity and dissolved oxygen) were examined. Vibrio cholerae was investigated with conventional culture methods and with Direct Immunofluorescence (DFA-VNC) in order to detect viable non culturable organisms. All isolated microorganisms corresponded to Vibrio cholerae non-O1 and non-O139 (Lules 26%, Canal Norte 33% and Banda 41%). The majority was found during spring and summer and correlated with temperature and pH. Non culturable Vibrio cholerae O1 was detected year round in 38 of the 54 water samples analyzed. Application of the Pearson correlation coefficient revealed that there was no relationship between positive immunofluorescence results and environmental physicochemical parameters. Genes coding for somatic antigen O1 were confirmed in all DFA-VNC-positive samples, whereas the virulence-associated ctxA and tcpA genes were confirmed in 24 samples.
authors: Departamento de Microbiología Clínica, Facultad Bioquímica, Química, Farmacia y Biotecnología, Universidad Nacional de Tucumán, Argentina.
authors: Olga
authors: O
authors: Aulet
authors: Clara
authors: C
authors: Silva
authors: Sol González
authors: SG
authors: Fraga
authors: Mariana
authors: M
authors: Pichel
authors: Rosa
authors: R
authors: Cangemi
authors: Cristina
authors: C
authors: Gaudioso
authors: Norma
authors: N
authors: Porcel
authors: Maria Angela
authors: MA
authors: Jure
authors: Marta Cecilia
authors: MC
authors: de Castillo
authors: Noma
authors: N
authors: Binsztein
mesh_terms: D001118:Argentina; D004553:Electric Conductivity; D019085:Fluorescent Antibody Technique, Direct; D006863:Hydrogen-Ion Concentration; D016133:Polymerase Chain Reaction; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D013696:Temperature; D041241:Vibrio cholerae O1 / Q000302:isolation & purification*; D014871:Water Microbiology