gyrA mutations in quinolone-resistant isolates of the fish pathogen Aeromonas salmonicida

Oppegaard, Hanne; Sørum, Henning

doi:10.1128/aac.38.10.2460

Cited by 49 publications

(40 citation statements)

References 33 publications

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“…Therefore, discharge of quinolones in rivers, probably from an agricultural source, must have selected resistant mutants among indigenous bacterial populations (13). Indeed, quinolones are widely used in veterinary medicine in Europe (30) and more recently in the United States (4); these antibiotics are mostly excreted as unchanged substances and are among the most persistent drugs in the environment (17).…”

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confidence: 99%

Type II Topoisomerase Quinolone Resistance-Determining Regions of Aeromonas caviae , A. hydrophila, and A. sobria Complexes and Mutations Associated with Quinolone Resistance

Goñi-Urriza

Arpin

Capdepuy

et al. 2002

Antimicrob Agents Chemother

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Most Aeromonas strains isolated from two European rivers were previously found to be resistant to nalidixic acid. In order to elucidate the mechanism of this resistance, 20 strains of Aeromonas caviae (n ‫؍‬ 10), A. hydrophila (n ‫؍‬ 5), and A. sobria (n ‫؍‬ 5) complexes, including 3 reference strains and 17 environmental isolates, were investigated. Fragments of the gyrA, gyrB, parC, and parE genes encompassing the quinolone resistance-determining regions (QRDRs) were amplified by PCR and sequenced. Results obtained for the six sensitive strains showed that the GyrA, GyrB, ParC, and ParE QRDR fragments of Aeromonas spp. were highly conserved (>96.1% identity), despite some genetic polymorphism; they were most closely related to those of Vibrio spp., Pseudomonas spp., and members of the family Enterobacteriaceae (72.4 to 97.1% homology). All 14 environmental resistant strains carried a point mutation in the GyrA QRDR at codon 83, leading to the substitution Ser-833Ile (10 strains) or Ser-833Arg. In addition, seven strains harbored a mutation in the ParC QRDR either at position 80 (five strains), generating a Ser-803Ile (three strains) or Ser-803Arg change, or at position 84, yielding a Glu-843Lys modification. No amino acid alterations were discovered in the GyrB and ParE QRDRs. Double gyrA-parC missense mutations were associated with higher levels of quinolone resistance compared with the levels associated with single gyrA mutations. The most resistant strains probably had an additional mechanism(s) of resistance, such as decreased accumulation of the drugs. Our data suggest that, in mesophilic Aeromonas spp., as in other gram-negative bacteria, gyrase and topoisomerase IV are the primary and secondary targets for quinolones, respectively.

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Type II Topoisomerase Quinolone Resistance-Determining Regions of Aeromonas caviae , A. hydrophila, and A. sobria Complexes and Mutations Associated with Quinolone Resistance

Goñi-Urriza

Arpin

Capdepuy

et al. 2002

Antimicrob Agents Chemother

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“…There are several reports on the association between mutations in the QRDRs of the corresponding genes gyrA and parC and resistance to fluoroquinolones in other gram-negative bacteria and in gonococci (8,11,16,17,19,21). Mutations in gyrB have been evaluated for several gram-negative bacteria, including N. gonorrhoeae (8,12).…”

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Comparison of Mismatch Amplification Mutation Assay with DNA Sequencing for Characterization of Fluoroquinolone Resistance in Neisseria gonorrhoeae

et al. 2004

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A mismatch amplification mutation assay (MAMA) was developed for identification of point mutations in quinolone resistance-determining region (QRDR) of gyrA at codons 91 and 95. MAMA PCR was used to detect mutations at codons 91 and 95 of gyrA in 117 Neisseria gonorrhoeae isolates (with ciprofloxacin MICs of 0.004 to >32 g/ml) from Bangladesh during 1997 to 2001. The QRDR regions of the gyrA genes from 31 randomly selected isolates were sequenced, and the results were compared with those of MAMA PCR. Using mismatch PCR, a mutation at Ser91 could be detected in all 27 (resistant and intermediate) isolates, and an Asp95-to-Gly95 mutation could be detected in all 15 isolates, as detected by sequencing. MAMA PCR offers a simple, inexpensive, rapid, and easier alternative for detection of point mutations in fluoroquinolone resistance in N. gonorrhoeae.

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“…Reports have indicated the necessity of concurrent point mutations in both gyrA and parC for high-level quinolone resistance in several clinical and environmental strains of aeromonads (19,23). These isolates had double mutations at codon 83 (Ser¡Ile/ Arg) of the gyrA QRDR, coupled with a missense mutation at position 80 (Ser¡Ile/Phe) in the parC QRDR.…”

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“…A majority of mutations described to date in Gram-negative bacteria have been found within the N termini of the gyrA, gyrB, and parC proteins, between codons 83 and 87 in the QRDRs (1,3,10,18,19,22,23). Mutations at these locations alter the binding of quinolones to the active site and lead to reduced susceptibility (22,23).…”

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Molecular Characterization of Fluoroquinolone-Resistant Aeromonas spp. Isolated from Imported Shrimp

Shakir

Khan

Sung

et al. 2012

Appl Environ Microbiol

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bSixty-three nalidixic acid-resistant Aeromonas sp. isolates were obtained from imported shrimp. Phylogenetic analysis of gyrB sequences indicated that 18 were A. enteropelogenes, 26 were A. caviae, and 19 were A. sobria. Double missense mutations in the quinolone resistance-determining region (QRDR) of gyrA at codon 83 (Ser¡Val/Ile) and codon 92 (Leu¡Met) coupled with a point mutation of parC at codon 80 (Ser¡Ile/Phe) conferred high levels of quinolone resistance in the isolates. A majority of A. enteropelogenes and A. caviae strains harbored toxin genes, whereas only a few A. sobria strains harbored these genes. The fluoroquinolone-resistant Aeromonas spp. exhibited higher cytotoxicity than fluoroquinolone-sensitive, virulent Aeromonas spp. to rat epithelial cells. The United States in 2009 imported 589,670 metric tons of farmed shrimp worth more than $6 billion from Asia (27). Copious amounts of antibiotics are used in the shrimp ponds to stimulate growth and to retard the incidence of diseases caused by overcrowded, factory farm conditions (4, 5, 9). The indiscriminate use of these antibiotics may select bacteria resistant to multiple antibiotics, and such bacteria may transfer their antibiotic resistance determinants to pathogenic bacteria (14,16).Aeromonads are ubiquitous, psychrophilic, Gram-negative microbes commonly found in fresh water, estuaries, and other coastal waters (6,7,8). They are known to cause hemorrhagic septicemia in aquatic organisms. These microbes also cause several diseases in penaeid shrimp (5). Antibiotics, such as fluoroquinolones, are used to curtail infections (5, 9). However, prolonged abuse of antibiotics could result in the selection of fluoroquinolone-resistant Aeromonas spp. (20). The presence of fluoroquinolone-resistant aeromonads in shrimp could pose public health concerns because these bacteria are associated with outbreaks of human infectious diseases in immunocompromised patients (9, 29). Quinolones are the drugs of choice for the treatment of Aeromonas-induced infections (11). Thus, U.S. regulatory agencies, such as the FDA and CDC (28), want to limit the prevalence of fluoroquinolone-resistant bacteria in food-producing animals to protect the efficacy of the drugs. Since little information is available on the prevalence of fluoroquinolone-resistant aeromonads in imported shrimp, we decided to investigate the prevalence of fluoroquinolone-resistant Aeromonas spp. and the mechanism of resistance in these bacteria to the antibiotic. We report here for the first time that imported shrimp may be a reservoir of virulent, fluoroquinolone-resistant strains of A. enteropelogenes, A. caviae, and A. sobria.Isolation, characterization, and identification of bacteria. Bacteria were isolated from frozen shrimp (Penaeus monodon) imported from Thailand. Typically, 2 g of thawed shrimp sample was enriched for 6 h in alkaline peptone medium (pH 8.0) supplemented with 30 g/ml of ampicillin and nalidixic acid. Enriched samples were streaked on MacConkey agar and incubated at 37°C overnig...

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gyrA mutations in quinolone-resistant isolates of the fish pathogen Aeromonas salmonicida

Cited by 49 publications

References 33 publications

Type II Topoisomerase Quinolone Resistance-Determining Regions of Aeromonas caviae , A. hydrophila, and A. sobria Complexes and Mutations Associated with Quinolone Resistance

Type II Topoisomerase Quinolone Resistance-Determining Regions of Aeromonas caviae , A. hydrophila, and A. sobria Complexes and Mutations Associated with Quinolone Resistance

Comparison of Mismatch Amplification Mutation Assay with DNA Sequencing for Characterization of Fluoroquinolone Resistance in Neisseria gonorrhoeae

Molecular Characterization of Fluoroquinolone-Resistant Aeromonas spp. Isolated from Imported Shrimp

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