Occurrence, Virulence and Antimicrobial Resistance-Associated Markers in Campylobacter Species Isolated from Retail Fresh Milk and Water Samples in Two District Municipalities in the Eastern Cape Province, South Africa

Abstract

Campylobacter species are among the major bacteria implicated in human gastrointestinal infections and are majorly found in faeces of domestic animals, sewage discharges and agricultural runoff. These pathogens have been implicated in diseases outbreaks through consumption of contaminated milk and water in some parts of the globe and reports on this is very scanty in the Eastern Cape Province. Hence, this study evaluated the occurrence as well as virulence and antimicrobial-associated makers of Campylobacter species recovered from milk and water samples. A total of 56 water samples and 72 raw milk samples were collected and the samples were processed for enrichment in Bolton broth and incubated for 48 h in 10% CO2 at 42 °C under microaerobic condition. Thereafter, the enriched cultures were further processed and purified. After which, presumptive Campylobacter colonies were isolated and later confirmed by PCR using specific primers for the detection of the genus Campylobacter, target species and virulence associated genes. Antimicrobial resistance profiles of the isolates were determined by disk diffusion method against a panel of 12 antibiotics and relevant genotypic resistance genes were assessed by PCR assay. A total of 438 presumptive Campylobacter isolates were obtained; from which, 162 were identified as belonging to the genus Campylobacter of which 36.92% were obtained from water samples and 37.11% from milk samples. The 162 confirmed isolates were further delineated into four species, of which, 7.41%, 27.16% and 8.64% were identified as C. fetus, C. jejuni and C. coli respectively. Among the virulence genes screened for, the iam (32.88%) was most prevalent, followed by flgR (26.87%) gene and cdtB and cadF (5.71% each) genes. Of the 12 antibiotics tested, the highest phenotypic resistance displayed by Campylobacter isolates was against clindamycin (95.68%), while the lowest was observed against imipenem (21.47%). Other high phenotypic resistance displayed by the isolates were against erythromycin (95.06%), followed by ceftriaxone (93.21%), doxycycline (87.65%), azithromycin and ampicillin (87.04% each), tetracycline (83.33%), chloramphenicol (78.27%), ciprofloxacin (77.78%), levofloxacin (59.88%) and gentamicin (56.17%). Relevant resistance genes were assessed in the isolates that showed high phenotypic resistance, and the highest resistance gene harbored by the isolates was catII (95%) gene while VIM, KPC, Ges, bla-OXA-48-like, tetC, tetD, tetK, IMI and catI genes were not detected. The occurrence of this pathogen and the detection of virulence and antimicrobial resistance-associated genes in Campylobacter isolates recovered from milk/water samples position them a risk to human health.

Campylobacter jejuni from Slaughter Age Broiler Chickens: Genetic Characterization, Virulence, and Antimicrobial Resistance Genes

“…Multiple virulence genes ( n = 7) were observed in 12 isolates, and one isolate harbored all six virulence genes investigated in this study. These results are in line with the reports of Igwaran et al and Han et al [ 6 , 47 ], where the isolates carried more than three virulence genes. The detection of these genes in these isolates indicates the pathogenic potential of the isolates [ 10 ].…”

“…Molecular detection of the antibiotic resistance gene disclosed the presence of 9 genes of which 2 were for tetracycline resistance ( tet O (42.3%) and tet A (26.9%)). This finding is similar to previous findings of 92.3%, 83.1%, and 43.5% of tet O gene that was detected in pigs, poultry, and broiler chicken in South Africa, Iran, and China, respectively [ 6 , 60 , 61 ]. More specifically, about 81% of the isolates were tetracycline (TET) resistant and carried the tet O gene, 33% carried the tet A gene, and 14.2% carried both tet O and tet A genes.…”

“…rectus [ 5 ]. Of these, C. jejuni , C. lari , and C. coli are documented as the main contributors to food-borne diseases such as campylobacteriosis in humans [ 3 , 6 , 7 ].…”

“…Antibiotic resistance is a global health issue that involves the transfer of bacteria and genes between humans and animals [ 15 ]. A number of genes which confer resistance to antibiotics in Campylobacter have been determined by previous studies [ 2 , 6 , 11 ]…”

Molecular Detection of Fluoroquinolone Resistance among Multidrug-, Extensively Drug-, and Pan-Drug-Resistant Campylobacter Species in Egypt

“…In the current study, all Campylobacter isolates had MAR indices of 0.5 or greater. These results were higher than those recorded in a previous study conducted in South Africa, where MAR indices of the tested isolates were 0.2 or lower [ 36 ]. The high resistance rates of Campylobacter isolates in developing countries could be due to the uncontrolled usage of antimicrobials in veterinary medicine as growth promoters and in human and animal treatments without any prescription.…”