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Updated: Jun 7, 2026
Detection and Isolation of Campylobacter spp. from Raw Meat
Published on: February 23, 2024
Detection of gyrA mutation among clinical isolates of Campylobacter jejuni isolated in Egypt by MAMA-PCR
Mayar M Said1, Hanan El-Mohamady, Fawkia M El-Beih
1US. Naval Medical Research Unit#3, Cairo, Egypt. mayar.said.eg@med.navy.mil
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 368 bp 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 μg/ml) and (CIP; 4 - >32 μg/ml). The other 11 sensitive C. jejuni isolates with MIC values (NA; 0.38 - 3 µg/ml) and (CIP; 0.03 - 0.125 µg/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.
Insights
Fluoroquinolone resistance in Campylobacter jejuni is primarily caused by a gyrA gene mutation. MAMA PCR is an effective and quick method for detecting this resistance in Egyptian isolates.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Campylobacter spp., particularly Campylobacter jejuni, are leading causes of human enteritis.
- Fluoroquinolones like ciprofloxacin are standard treatments, but resistance is increasing globally.
- A common resistance mechanism involves a specific mutation (C-257 to T) in the gyrA gene's quinolone resistance-determining region (QRDR), leading to a threonine to isoleucine change at position 86 (Thr-86 to Ile).
Purpose of the Study:
- To investigate the prevalence and mechanisms of fluoroquinolone resistance in Campylobacter isolates from Egypt.
- To confirm the role of the gyrA gene mutation in ciprofloxacin resistance.
- To evaluate the efficacy of Mismatch Amplification Mutation Assay (MAMA) PCR for detecting this resistance.
Main Methods:
- 118 Campylobacter isolates from Egypt (1998-2005) were analyzed.
- Polymerase Chain Reaction (PCR) was used to confirm the presence of the C. jejuni gyrA gene.
- Mismatch Amplification Mutation Assay (MAMA) PCR was employed to detect the specific C-257 to T alteration.
- Minimum Inhibitory Concentrations (MICs) for nalidixic acid and ciprofloxacin were determined using E-tests.
Main Results:
- The C. jejuni gyrA gene was identified in 100 isolates; 18 were identified as Campylobacter coli.
- The gyrA mutation was present in 89 C. jejuni isolates exhibiting high resistance to nalidixic acid (MICs 8 - >256 μg/ml) and ciprofloxacin (MICs 4 - >32 μg/ml).
- Eleven sensitive C. jejuni isolates lacked the mutation and showed significantly lower MIC values, with 100% concordance between MAMA PCR, MICs, and gyrA sequencing.
Conclusions:
- The primary mechanism of fluoroquinolone resistance in Egyptian Campylobacter isolates is the alteration in the gyrA QRDR.
- MAMA PCR is a cost-effective and rapid diagnostic tool for screening fluoroquinolone resistance in Campylobacter.
