A high proportion of Vibrio cholerae strains isolated from children with diarrhoea in Bangkok, Thailand are multiple antibiotic resistant and belong to heterogenous non-O1, non-O139 O-serotypes

Abstract

Results of a surveillance on cholera conducted with patients seen at the Children Hospital in Bangkok, Thailand from August 1993 to July 1995 are presented. Annually, isolation rates for Vibrio cholerae varied between 1.7 and 4.4% of patients with diarrhoea. V. cholerae O1 serotype Ogawa accounted for between 31 and 47% of patients cultured positive for V. cholerae, whereas the O139 serotype dominated in early 1994 after which it disappeared. Non-O1, non-0139 strains were isolated at similar rates as serotype O1 in 1993 and 1994, but accounted for 69% of V. cholerae culture positive specimens in 1995. However, the annual proportion of the isolation of non-O1, non-O139 strains showed little variation and remained low between 1.0 and 1.3%. Serotyping of 69 epidemiological unrelated non-O1, non-O139 strains produced 37 different O-serotypes. BglI ribotyping of serotypes containing more than two strains demonstrated a high degree of heterogeneity within and between serotypes, except seven serotype O37 strains which showed an identical ribotype suggesting clonality. None of the 69 strains hybridized with a cholera toxin probe and only two strains hybridized with a heat-stable enterotoxin probe. Susceptibility testing to 12 antibiotics showed that 40 of 69 (58%) non-O1, non-O139 strains were resistant to colistin, streptomycin and sulphisoxazole and 28 of 69 (41%) were multiple antibiotic resistant (MAR; > or = 4 antibiotics). Although 26 of 69 (38%) strains contained one or more plasmids, the plasmids were of low molecular weights and did not seem to encode antibiotic resistance. The results of the present study showed that a high proportion of heterogenous MAR V. cholerae non-O1, non-O139 strains were isolated from children at the hospital. With reference to the emergence of V. cholerae O139 in 1992, we suggest that non-O1, non-O139 strains should be monitored carefully to detect new serotypes with a possible epidemic potential, but also to determine the development and mechanism of antibiotic resistance.

A molecular and phenotypic study of Vibrio cholerae in Iran

“…Although the re-arrangement and copy number of the virulence cassette may play an important role in determining the pathogenicity level of the isolates [34], the presence of a virulence cassette could be variable, as it is subjected to amplification and deletion under the control of the recA gene [34]. Moreover, the data obtained in the present study were also in accordance with other reports [35][36][37], i.e., V. cholerae non-O1, non-O139 strains rarely harbour cholera toxin genes or other virulence genes contained in the virulence cassette found in O1 and O139.…”

“…Ribotyping with the Bgll restriction endonuclease produced four distinct patterns amongst the V. cholerae isolates in this study, three of which were in serotype O1 isolates, and the fourth in non-O1, non-O139 isolates. Ribotype pattern 1 was a representative of non-O1, non-O139 V. cholerae isolates in Iran, which was similar to that reported by Dalsgaard et al [36] in Thailand. Pattern 2 was recognised as V. cholerae O1 ribotype B15 in our database.…”

“…A similar pattern has also been reported in isolates from Thailand [5], referred to as type R1, and from isolates in Turkey, Romania and Lebanon [41]. Ribotype pattern 4 has been designated as type R3 by investigators of isolates from Vietnam, India, Thailand and Bangladesh [36,42].…”

“…PFGE and ribotyping of V. cholerae O1 isolates from Bangladesh and India have demonstrated that the O1 serotype, which re-appeared after being temporarily displaced by V. cholerae O139, may represent a new clone [4,38,39]. The suggestion has been made [36,40] that the new V. cholerae ribotype found in India, Bangladesh and Guinea-Bissau could be the cause of new epidemics. Ribotyping with the Bgll restriction endonuclease produced four distinct patterns amongst the V. cholerae isolates in this study, three of which were in serotype O1 isolates, and the fourth in non-O1, non-O139 isolates.…”

Gene Cloning and Characterization of VcrM, a Na+‐Coupled Multidrug Efflux Pump, from Vibrio cholerae Non‐O1

“…Both clinical and environmental strains of V. cholerae (O1 and non-O1) which are multiply resistant to antimicrobial agents have been reported with increasing frequency (5,7,(11)(12)(13). Even though some reports demonstrated that the presence of antibiotic resistance genes in plasmids or integrons in V. cholerae were the cause of resistance to antimicrobial agents, the mechanisms of resistance in other cases are unknown and remain to be determined (5,7,28). Therefore, we are investigating the possible involvement of multidrug efflux pumps as the causative agent of multidrug resistance in V. cholerae.…”