J Med Microbiol 55 (2006), 575-583; DOI: 10.1099/jmm.0.46339-0
© 2006 Society for General Microbiology
ISSN 1473-5644
Distribution and characterization of integrons in various serogroups of Vibrio cholerae strains isolated from diarrhoeal patients between 1992 and 2000 in Kolkata, India
Lei Shi1,7,
Kazutaka Fujihara1,
Toshio Sato2,
Hideaki Ito1,3,
Pallavi Garg4,
Rupa Chakrabarty4,
Thandavarayan Ramamurthy4,
G. Balakrish Nair5,
Yoshifumi Takeda6 and
Shinji Yamasaki1
1 Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-Cho, Sakai, Osaka 599-8531, Japan
2 Research Institute, International Medical Center of Japan, Tokyo, Japan
3 Dainippon Pharmaceutical Co. Ltd., Osaka, Japan
4 National Institute of Cholera and Enteric Diseases, Calcutta, India
5 International Center for Diarrhoeal Diseases Research, Dhaka, Bangladesh
6 Cine-Science Laboratory, Tokyo, Japan
7 College of Light Industry and Food Technology, South China University and Technology, Guangdong, PR China
Correspondence
Shinji Yamasaki
shinji{at}vet.osakafu-u.ac.jp
Received 20 September 2005
Accepted 3 January 2006
A total of 133 clinical strains of Vibrio cholerae comprising 44 strains of O1, 45 strains of O139 and 44 strains of non-O1, non-O139 serogroups isolated from hospitalized patients in Kolkata, India, from 1992 to 2000 was examined for the presence of class 1, 2 and 4 integrons. By PCR and DNA sequencing, seven strains of O1, one strain of O139 and six strains of non-O1, non-O139 serogroups were found to contain class 1 integron-harbouring genes aadA1, aadA2 (encoding resistance to streptomycin and spectinomycin), blaP1 (resistance to ß-lactams), aar-3 (resistance to rifampicin), aacA4 (resistance to kanamycin and gentamicin), and dfrA1 and dfrA15 (resistance to trimethoprim). Most strains produced one or two bands using primers specific for the amplification of the variable region where the antibiotic-resistance genes are located, and their sizes ranged from 700 to 1250 bp. However, one strain of V. cholerae O1 isolated in 1994 gave a 2483 bp fragment, the largest fragment so far found in a class 1 integron of V. cholerae O1. No strain was positive for the intI2 gene. All V. cholerae strains, regardless of serogroup, were positive for the intI4 gene by PCR and using a colony hybridization test. Amplification of the intI4 gene by PCR yielded a 2200 bp fragment (1260 bp larger than the expected size) from three V. cholerae O139 strains isolated in 1999. Sequence analysis of this amplicon revealed an insertion of IS1359 in the middle of the intI4 gene. These data indicate that a class 1 integron is present in some clinical strains of V. cholerae isolated in Kolkata, India, and that a class 4 integron is ubiquitously distributed among V. cholerae strains regardless of serogroup.
Abbreviations: CS, conserved segment.
The GenBank/EMBL/DDBJ accession numbers for the sequences of the genes aacA1c (O1: VC2), aar-3–aacA4–dfrA1–orfc (O1: CO747), dfrA1–orfc (O139: CO406), dfrA1–orfc (non-O1 non-O139: SG6), dfrA15 (non-O1 non-O139: CO248), aadA2 (non-O1 non-O139: CO248), dfrA1–orfc (non-O1 non-O139: CO775), dfrA1–orfc (non-O1 non-O139: PG92), dfrA15 (non-O1 non-O139: NLC35), blaP1 (non-O1 non-O139: NLC35), aadA2 (non-O1 non-O139: NLC38), blaP1 (non-O1 non-O139: NLC38), intI4–IS1358–intI4 (O139: NLC31), intI4–IS1358–intI4 (O139: NLC40) and intI4–IS1358–intI4 (O139: NLC50) are AB219433, AB219436, AB219437, AB219453, AB219434, AB219435, AB219451, AB219452 and AB219454–AB219460, respectively.
Copyright © 2006 Society for General Microbiology.
