Use of a multiplex PCR-based assay to differentiate Campylobacter jejuni and Campylobacter coli strains isolated from human and animal sources

Occurrence, Risk Factors, and Antimicrobial Susceptibility Test of Thermophilic Campylobacter Species of Bovine Carcass at Municipal Abattoir and Butcher Shops of Jimma Town, Southwest Ethiopia

BACKGROUND

Although Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) cause acute diarrheal diseases in people all over the world, they are most commonly seen in other mammalian species and are a seemingly healthy carrier condition. Humans in Ethiopia, on the other hand, are largely unaware of the existence of Campylobacter in food animals as potential sources of infection.

OBJECTIVE

To determine the occurrence, risk factors, and antimicrobial susceptibility pattern of thermophilic Campylobacter species in bovine raw meat from the abattoir and butcher shops.

METHODS

Swab samples were collected from 177 cattle carcasses (from abattoir 93 and butcher shops 84) and cultured using standard methods. An antimicrobial susceptibility test was performed using the disk diffusion method towards eleven antimicrobial agents.

RESULTS

The overall prevalence of thermophilic Campylobacter species was 14 (7.9%). From these, 11 (78.6%) were identified to be C. jejuni and 3 (21.4%) were C. coli. Lack of handwashing before meat processing and after visiting the toilet, meat contact with floors, walls, or soiling during preparation, and lack of training were the most important factors independently associated with (p<0.05) the prevalence of Campylobacter species contamination. The highest level of antimicrobial resistance of the Campylobacter isolates was recorded to ampicillin (10μg) (100%), followed by amoxicillin (30μg) (78.6%) and sulphamethoxazole-trimethoprim (57.1%) while the least resisted antimicrobials were streptomycin (25μg), erythromycin (15μg), oxytetracycline (30μg) (each 28.6%), kanamycin (30μg) 14.3%, chloramphenicol (30μg) and gentamycin (10μg) (each 7.1%).

CONCLUSION

Despite the low prevalence of thermophilic Campylobacter in the current investigation, it may pose a significant public health threat. As a result, it is vital to give retailers and customers extensive education, training, and knowledge about the correct handling and cooking of animal-derived goods. Furthermore, antimicrobials should be used with caution in both veterinary and human treatment regimens as well as a wider examination of antimicrobial resistance patterns for the use of well-targeted antimicrobials.

Phenotypic and molecular characterization of erythromycin resistance in Campylobacter jejuni and Campylobacter coli strains isolated from swine and broiler chickens

ABSTRACT: Campylobacter spp. is a bacterial agent that causes gastroenteritis in humans and may trigger Guillain-Barré Syndrome (GBS) and is also considered one of the main foodborne diseases in developed countries. Poultry and pigs are considered reservoirs of these microorganisms, as well as raw or undercooked by-products are often incriminated as a source of human infection. Treatment in human cases is with macrolide, such erythromycin, that inhibits the protein synthesis of the microorganism. This study aimed to isolate Campylobacter jejuni and Campylobacter coli from intestinal content samples of broiler chickens (n=20) and swine (n=30) to characterize the erythromycin resistance profile of the strains and to detect molecular mechanisms involved in this resistance. The minimum inhibitory concentration was determined by agar dilution. The Mismatch Amplification Mutation Assay-Polymerase Chain Reaction (MAMA-PCR) was performed to detect mutations at positions 2074 and 2075 of 23S rRNA region, in addition to PCR test to detect the erm(B) gene. From the intestinal content of broiler chickens, 18 strains of C. jejuni and two strains of C. coli were isolated, whereas, from swine samples, no C. jejuni strain and 14 strains of C. coli were isolated. All C. coli strains were resistant, and three C. jejuni strains from broilers chickens were characterized with intermediate resistance to erythromycin. The MIC of the strains ranged from ≤0.5mg/μL to ≥128mg/μL. All resistant strains had the A2075G mutation, and one strain with intermediate resistance had the A2075G mutation. However, the A2074C mutation and the erm(B) gene were not detected. High resistance levels were detected in C. coli strains isolated from swine. The MAMA-PCR is a practical tool for detecting the erythromycin resistance in Campylobacter strains.

Multiplex PCR for direct identification of Campylobacter spp. in human and chicken stools

Differentiation between Campylobacter jejuni and Campylobacter coli is problematic in clinical specimens due to fastidious growth requirements and limited biochemical tests. This study describes a rapid, multiplex PCR protocol for the direct detection and differentiation of C. jejuni and C. coli in stools. An evaluation was carried out of this multiplex protocol based on the detection of cadF (genus specific), and hipO (C. jejuni) and asp (C. coli) genes, using stool from patients with Campylobacter enteritis and chicken. Protocol sensitivity was assessed and specificity determined using a panel of enteric bacteria, and evaluation of 30 diarrhoeic stool specimens culture negative for Campylobacter. Of the 114 specimens (54 human and 60 chicken) evaluated by the protocol, 70 (61.4 %) were identified as C. jejuni, 35 (30.7 %) as C. coli and 9 (7.9 %) as a mixed infection/colonization with both species. All mixed infections were identified as C. jejuni by culture. Among the stool specimens that were culture negative for Campylobacter, two (6.7 %) were C. jejuni positive by multiplex PCR. The protocol sensitivity limit was 0.015-0.016 ng C. jejuni and C. coli DNA mul(-1) in the specimen. There was no cross-reaction with the reference strains assessed. Comparison of hippurate test and multiplex PCR demonstrated 17 isolates with false-positive hippurate enzymic activity and 7 with false-negative activity. This rapid protocol (turnaround time 6 h) is highly sensitive and specific for direct evaluation of stool for these pathogens. It has significant application for routine clinical diagnostic and epidemiological purposes.

Application of biochemical and polymerase chain reaction assays for identification of Campylobacter isolates from non-human primates

A multiplex polymerase chain reaction (PCR) assay was performed on 167 thermophilic campylobacters isolated from non-human primates. Samples were first identified by phenotypic methods resulting in 64 Campylobacter jejuni and 103 C. coli strains. Four strains identified biochemically as C. coli, were then determined to be C. jejuni by PCR. Comparison of methodologies showed that the main discrepancies were attributed to the hippurate hydrolysis test and sensitivity to cephalothin and nalidixic acid. Analysis of data showed that the application of phenotypic methods should be supplemented by a molecular method to offer a more reliable Campylobacter identification.