Hindawi Publishing Corporation Te Scientifc World Journal Volume 2013, Article ID 746254, 5 pages http://dx.doi.org/10.1155/2013/746254 Research Article The Aquatic Environment as a Reservoir of Vibrio cholerae O1 in Hydrographic Basins of the State of Pernambuco, Brazil Carina Lucena Mendes-Marques, 1 Vladimir da Mota Silveira Filho, 1 Ana Paula Rocha da Costa, 1 Mariana de Lira Nunes, 1 Sandoval Vieira da Silva Filho, 2 Ângela Cristina Torres de Araújo Figueirôa, 2 Ernesto Hofer, 3 Alzira Maria Paiva de Almeida, 1 and Nilma Cintra Leal 1 1 Centro de Pesquisas Aggeu Magalh˜ aes, FIOCRUZ-PE, Avendia Professor Moraes Rego, s/n. Cidade Universit´ aria, 50670-420 Recife, PE, Brazil 2 Laborat´ orio Central de Sa´ ude P´ ublica Dr. Milton Bezerra Sobral (LACEN-PE), Secretaria Estadual de Sa´ ude de Pernambuco (SES- PE), Prac ¸a Oswaldo Cruz, s/n. Boa Vista, 50050-911 Recife, PE, Brazil 3 Instituto Oswaldo Cruz (IOC), FIOCRUZ-RJ, Avenida Brasil, 4365 Manguinhos, 21040-360 Rio de Janeiro, RJ, Brazil Correspondence should be addressed to Carina Lucena Mendes-Marques; clmendes@gmail.com Received 6 December 2012; Accepted 23 January 2013 Academic Editors: K. Ohmiya, J. L. Romalde, and D. Zhou Copyright © 2013 Carina Lucena Mendes-Marques et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Afer the worldwide cholera epidemic in 1993, permanent environmental monitoring of hydrographic basins was established in Pernambuco, Brazil, where cholera is endemic. Afer a quiescent period, 4 rfN (serogroup O1) positive water samples that were culture negative were detected by multiplex single-tube nested PCR (MSTNPCR); 2 of these were also ctxA (cholera toxin) positive. From May to June 2012, 30 V. cholerae O1 isolates were obtained by culturing samples. Tese isolates were analyzed for the presence of virulence genes by PCR, intergenic spacer region 16S-23S PCR (ISR-PCR), and pulsed feld gel electrophoresis (PFGE). Te isolates were positive for the rfN gene and negative for the assessed pathogenic genes and were classifed into 2 groups by ISR and the same profle by PFGE. Close genetic similarity was observed between them (2012) and environmental strains from 2004 to 2005, indicating the permanence of endemic V. cholerae O1 in the region. 1. Introduction Vibrio cholerae has played a prominent role in human history and has caused several epidemics that caused many deaths worldwide. While more than 200 O serogroups of V. cholerae have been identifed, only the O1 and O139 serogroups have been associated with epidemics [1]. Other serogroups commonly known as non-O1/non-O139 [2] coexist in the environment with O1 strains [3]. In Brazil, the O1 serogroup has been recognized as the causative agent of past epidemics, but it is likely that other serogroups were involved in recent small outbreaks [4, 5]. Since the last world cholera epidemic in 1993 [6], the Pernambuco (PE) state Department of Health (Secretaria Estadual de Sa´ ude (SES/PE)) has established permanent environmental monitoring of the hydrographic basins in the state for the detection of V. cholerae [7]. Tis investigation was frst based on the standard culture procedures of water samples, and later a molecular technique, multiplex single- tube nested PCR (MSTNPCR), is used to target the ctxA gene, which encodes cholera toxin subunit A, and the rfN gene, which is specifc to serogroup O1 [8]. In May 2012, four rfN positive but not culturable water samples, of which two were ctxA (cholera toxin) positive, were detected by MSTNPCR. Afer that, the monitoring was intensifed and, from May to June 2012, 30 V. cholerae O1-positive cultures were unexpectedly isolated from four hydrographic basins.