Role of Active Efflux in Association with Target Gene Mutations in Fluoroquinolone Resistance in Clinical Isolates of
            <i>Vibrio cholerae</i>

Baranwal, Somesh; Dey, Keya; Ramamurthy, T.; Nair, G. Balakrish; Kundu, Manikuntala

doi:10.1128/aac.46.8.2676-2678.2002

Cited by 70 publications

(54 citation statements)

References 15 publications

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“…Analysis of the gyrA and parC (VC1258 and VC2430, respectively, in Table S3) genes revealed two point mutations in the Haitian strains, i.e., a ser83ile substitution in gyrA and a ser85leu substitution in parC. Both point mutations are associated with quinolone resistance in clinical V. cholerae and have been reported in India and most recently in Nigeria and Cameroon (33)(34)(35)(36)(37). We observed the same point mutations in gyrA and parC in recent isolates from Zimbabwe (CP1038), Thailand (CP1042), and Bangladesh (CP1048).…”

mentioning

confidence: 99%

Genomic diversity of 2010 Haitian cholera outbreak strains

Hasan

Choi

Eppinger

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

173

212

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The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that Vibrio cholerae , the etiologic agent of cholera, remains a scourge. We report the isolation of both V . cholerae O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of V. cholerae coexisted in Haiti early in the epidemic. As non-O1/O139 V . cholerae was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with V . cholerae O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian V . cholerae O1 and V . cholerae non-O1/O139 strains. A total of 47 V . cholerae O1 and 29 V . cholerae non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of V . cholerae isolated in concurrent epidemics outside Haiti and 27 V . cholerae genomes available in the public database demonstrated substantial diversity of V. cholerae and ongoing flux within its genome.

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mentioning

confidence: 99%

Genomic diversity of 2010 Haitian cholera outbreak strains

Hasan

Choi

Eppinger

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

173

212

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“…Mutation at position 68 on the GyrA results in loss of charge, bulkiness and stability of GyrA and increases the MIC values to these drugs. Point mutations exclusively in the QRDR regions of topoisomerase genes may not be the sole contributing factor for bacterial resistance to quinolone antibiotics, suggesting that other possible mechanisms may also play a role in conferring resistance to these antibiotics (Baranwal et al, 2002;Ghosh et al, 1998;Hopkins et al, 2005Karczmarczyk et al, 2011Poole, 2000;Webber and Piddock, 2003). Since none of the isolates examined in this study contained any of the plasmid-mediated quinolone resistance genes (qnr), high levels of quinolone resistance could be a function of decreased accumulation of the antibiotics due to active efflux pumps.…”

Section: Discussionmentioning

confidence: 96%

“…s 2.6. Determination of efflux pump activity in the quinolone-sensitive and resistant strains of V. parahaemolyticus: Efflux pump activity was determined as described previously (Baranwal et al, 2002;Karczmarczyk et al, 2011). For determination of the presence of active efflux, ethidium bromide at a final concentration of 2 µg/ml was added immediately before the reading in a Synergy 2 Multi-Mode Microplate Reader (BIOTEK Instruments, Winooski, VT).…”

Section: Detection Of Mutations In the Quinolone Resistance Determinimentioning

confidence: 99%

“…Fluorescence was read every 1 min at excitation 530 nm and emission 600 nm for the next 30 min. Carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of the efflux pump (Baranwal et al, 2002;Webber and Piddock, 2003), at a final concentration of 100 µM, was added to the assay mixture. The natural fluorescence of the cells was subtracted and the fluorescence intensity was expressed in relative fluorescence units (RFU).…”

Section: Detection Of Mutations In the Quinolone Resistance Determinimentioning

confidence: 99%

“…Thus, U.S. regulatory agencies, such as United States Food and Drug Administration (USFDA) and Centers for Disease Control and Prevention (CDC), want to limit the prevalence of quinoloneresistant bacteria in food-producing animals to protect the efficacy of the quinolone drugs for human use (USFDA, 1997). Several different kinds of mechanisms confer bacterial resistance to quinolone antibiotics (Baranwal et al, 2002;Ghosh et al, 1998;Hopkins et al, 2005;Karczmarczyk et al, 2011;Poole, 2000;Ruiz, 2003;Yoshida et al, 1991). In Gramnegative bacteria, resistance to quinolones is mainly due to chromosomal mutations in the quinolone resistance determining region (QRDR) of genes encoding the drug target enzymes (DNA gyrase and topoisomerase IV) and a majority of mutations in these bacteria have been found within the N termini of GyrA (between codons Ala67-Gln106), GyrB (between codons Asp426-Lys447) and ParC proteins (between codons 83 and 87).…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of Quinolone Resistance in Vibrio parahemolyticus strains Isolated from Imported Shrimp

Nawaz

Sung

Gokulan

et al. 2015

MRAJ

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Sixty-one quinolone-resistant strains of Vibrio parahaemolyticus were isolated from 247 shrimp samples. These isolates had MICs of 256 and 4-8 µg/mL for nalidixic acid and ciprofloxacin respectively. Template DNA of the 61 isolates were screened by PCR for the quinolone resistance genes. Purified PCR amplicons of gyrA, gyrB and parC from these isolates were sequenced and analyzed for point mutations that confer resistance to these antibiotics. Point mutations in the quinolone resistance determining region (QRDR) of GyrA at positions 68, 83, 85 and 89 and in ParC at positions 85 as well as in the non QRDR of GyrA at positions 48 along with 4 different point mutations in GyrB at positions 311, 354, 360 and 374 conferred resistances to these antibiotics. Structural analysis were undertaken to determine the role of these four novel point mutations in V. parahaemolyticus at codons 48, 68, 83 and 89 on GyrA in enhanced MICs to quinolone antibiotics. Homology analysis indicated that all four mutations are localized in the vicinity of quinolone binding and DNA binding major grooves. These four mutations are known to play pivotal roles in readjusting the position of α-helices, stabilization of GyrA, loss of electrical charges or the formation of A2 dimers resulting in enhanced MICs to the quinolone antibiotics. Ethidium bromide uptake experiments indicated higher efflux pump activities in drug resistant V. parahaemolyticus than their sensitive counterparts. Our results indicate that imported shrimp is a reservoir of quinolone-resistant V. parahaemolyticus.

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Cholera Outbreaks in India

Ramamurthy

Sharma²

2014

Cholera Outbreaks

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Cholera is a global health problem as several thousands of cases and deaths occur each year. The unique epidemiologic attribute of the disease is its propensity to occur as outbreaks that may flare-up into epidemics, if not controlled. The causative bacterial pathogen Vibrio cholerae prevails in the environment and infects humans whenever there is a breakdown in the public health component. The Indian subcontinent is vulnerable to this disease due its vast coastlines with areas of poor sanitation, unsafe drinking water, and overcrowding. Recently, it was shown that climatic conditions also play a major role in the persistence and spread of cholera. Constant change in the biotypes and serotypes of V. cholerae are also important aspects that changes virulence and survival of the pathogen. Such continuous changes increase the infection ability of the pathogen affecting the susceptible population including the children. The short-term carrier status of V. cholerae has been studied well at community level and this facet significantly contributes to the recurrence of cholera. Several molecular tools recognized altering clonality of V. cholerae in relation with the advent of a serogroup or serotype. Rapid identification systems were formulated for the timely detection of the pathogen so as to identify and control the outbreak and institute proper treatment of the patients. The antimicrobials used in the past are no longer useful in the treatment of cholera as V. cholerae has acquired several mechanisms for multiple antimicrobial resistance. This upsurge in antimicrobial resistance directly influences the management of the disease. This chapter provides an overview of cholera prevalence in India, possible sources of infection, and molecular epidemiology along with antimicrobial resistance of V. cholerae.

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Role of Active Efflux in Association with Target Gene Mutations in Fluoroquinolone Resistance in Clinical Isolates of Vibrio cholerae

Cited by 70 publications

References 15 publications

Genomic diversity of 2010 Haitian cholera outbreak strains

Genomic diversity of 2010 Haitian cholera outbreak strains

Mechanisms of Quinolone Resistance in Vibrio parahemolyticus strains Isolated from Imported Shrimp

Cholera Outbreaks in India

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