Detection of gyrA mutation among clinical isolates of Campylobacter jejuni isolated in Egypt by MAMA-PCR.
JOURNAL OF INFECTION IN DEVELOPING COUNTRIES(2010)
摘要
Introduction: Campylobacter spp are the major cause of enteritis in humans and more than 90% of reported infections are caused by Campylobacter jejuni. Fluoroquinolones such as ciprofloxacin are the antibiotics of choice for treatment. An increase in the frequency of ciprofloxacin-resistant Campylobacter has been reported globally due to a single base mutation (C-257 to T) in codon 86 of the quinolone resistance determining region (QRDR) of the gyrA gene altering the amino acid sequence from threonine at position 86 to isoleucine (Thr-86 to Ile). Methodology: Campylobacter spp (n = 118) were selected from a collection of Egyptian isolates spanning 1998 to 2005. The presence of C. jejuni gyrA gene was confirmed in each isolate by a PCR assay amplifying 368bp portion of the gyrA gene. C to T alteration was detected by the mismatch amplification mutation assay MAMA PCR. The MIC of nalidixic acid (NA) and ciprofloxacin (CIP) was determined by E-test. Results: C. jejuni gyrA gene was detected in 100 of the Campylobacter spp studied; the other 18 isolates were found to be Campylobacter coli by lpxA PCR. The mutation was detected in 89 C. jejuni resistant isolates with MIC values (NA; 8 - >256 mu g/ml) and (CIP; 4 - >32 mu g/ml). The other 11 sensitive C. jejuni isolates with MIC values (NA; 0.38 - 3 mu g/ml) and (CIP; 0.03 - 0.125 mu g/ml) were not amplified by the MAMA primers. There was 100% congruence with MAMA PCR, MIC results and gyrA gene sequence analysis. Conclusions: In Egypt the main mechanism for resistance to fluoroquinolones is an alteration in the gyrA QRDR. MAMA PCR provides an economical and rapid means for screening fluoroquinolone resistance.
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关键词
fluoroquinolone resistance,mismatch sequence detection,Africa
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