Analysis of gyrA mutations in quinolone-resistant and -susceptible Campylobacter jejuni isolates from retail poultry and human clinical isolates by non-radioactive single-strand conformation polymorphism analysis and DNA sequencing.
OBJECTIVE
The aims of this study were to characterize the molecular variations in the quinolone resistance-determining region (QRDR) of gyrA among quinolone-resistant and -susceptible Campylobacter jejuni isolates originating from foods of animal origin and human infections and to evaluate the suitability of the single-strand conformation polymorphism (SSCP) method as a screening method for molecular characterization of fluoroquinolone resistance.


RESULTS
Alterations in QRDR of gyrA from 182 C. jejuni isolates were determined by nonradioisotopic SSCP analysis and direct sequencing. A total of 13 types of nucleic acid sequence combinations within the QRDR of the gyrA gene resulted in 11 different SSCP patterns. All nalidixic acid resistant strains possessed nucleotide substitution at either codon Thr-86 or Asp-90. Silent mutations were detected additionally. Thr-86 to Ile mutation was detected in all 139 ciprofloxacin resistant strains, which showed cross-resistance to nalidixic acid.


CONCLUSIONS
The SSCP method is suitable for a molecular screening of quinolone resistant C. jejuni isolates and in combination with DNA sequencing suitable to detect genetic variations of the QRDR of gyrA.


CONCLUSIONS
This study provides data of the genetic variations of the QRDR of gyrA from C. jejuni isolates of foods and human beings.
Beckmann
L
L
Bundesinstitut für Risikobewertung (BfR), Diedersdorfer Weg 1, Berlin, Germany.
Müller
M
M
Luber
P
P
Schrader
C
C
Bartelt
E
E
Klein
G
G
D000818:Animals; D001483:Base Sequence; D002169:Campylobacter Infections / Q000382:microbiology; D016123:Campylobacter jejuni / Q000235:genetics*; D027081:DNA Gyrase / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D024841:Fluoroquinolones; D005516:Food Microbiology; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D020125:Mutation, Missense / Q000235:genetics; D009268:Nalidixic Acid; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011200:Poultry / Q000382:microbiology; D015363:Quinolones
D004269:DNA, Bacterial; D024841:Fluoroquinolones; D015363:Quinolones; D009268:Nalidixic Acid; D027081:DNA Gyrase