Antibiotic resistance and virulence profiles of Proteus mirabilis isolated from broiler chickens at abattoir in South Africa.

BACKGROUND: Proteus mirabilis has been identified as an important zoonotic pathogen, causing several illnesses such as diarrhoea, keratitis and urinary tract infections. OBJECTIVE: This study assessed the prevalence of P. mirabilis in broiler chickens, its antibiotic resistance (AR) patterns, ESBL-producing P. mirabilis and the presence of virulence genes. METHODS: A total of 26 isolates were confirmed as P. mirabilis from 480 pooled broiler chicken faecal samples by polymerase chain reaction (PCR). The disk diffusion method was used to evaluate the antibacterial susceptibility test, while nine virulence genes and 26 AR genes were also screened by PCR. RESULTS: All 26 P. mirabilis isolates harboured the ireA (siderophore receptors), ptA, and zapA (proteases), ucaA, pmfA, atfA, and mrpA (fimbriae), hlyA and hpmA (haemolysins) virulence genes. The P. mirabilis isolates were resistant to ciprofloxacin (62%) and levofloxacin (54%), while 8 (30.7%) of the isolates were classified as multidrug resistant (MDR). PCR analysis identified the blaCTX-M gene (62%), blaTEM (58%) and blaCTX-M-2 (38%). Further screening for AMR genes identified mcr-1, cat1, cat2, qnrA, qnrD and mecA, 12%, 19%, 12%, 54%, 27% and 8%, respectively for P. mirabilis isolates. The prevalence of the integron integrase intI1 and intI2 genes was 43% and 4%, respectively. CONCLUSIONS: The rise of ciprofloxacin and levofloxacin resistance, as well as MDR strains, is a public health threat that points to a challenge in the treatment of infections caused by these zoonotic bacteria. Furthermore, because ESBL-producing P. mirabilis has the potential to spread to humans, the presence of blaCTX -M -producing P. mirabilis in broilers should be kept under control. This is the first study undertaken to isolate P. mirabilis from chicken faecal samples and investigate its antibiotic resistance status as well as virulence profiles in South Africa.

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

Campylobacter jejuni is a major cause of food-borne human gastroenteritis worldwide and is designated as a high priority antimicrobial-resistant pathogen by the World Health Organization (WHO). In this study, a total of 26 C. jejuni isolates from broiler chickens were screened for the presence of virulence and antimicrobial resistance genes by PCR. As a result, the study detected 11/26 (42.3%), 9/26 (34.6%), 8/26 (30.8%), 7/26 (26.9%), 6/26 (23.1%), and 6/26 (23.1%) of cdtC, pldA, cdtB, cdtA, cadF, and ciaB virulence genes, respectively, with seven of the isolates carrying more than two virulence genes. The majority of the isolates n = 25 (96.1%) were resistant to nalidixic acid, followed by n = 21 (80.7%), n = 22 (84.6%), and n = 5 (19.2%) for tetracycline, erythromycin, and ciprofloxacin, respectively. Most isolates were harboring catI (n = 16; 84.2%), catII (n = 15; 78.9%), catIII (n = 10; 52.6%), catIV (n = 2; 10.5%), floR (n = 10; 52.6%), ermB (n = 14; 73.7%), tetO (n = 13; 68.4%), tetA (n = 9; 47.4%), mcr-4 (n = 8; 42.1%), and ampC (n = 2; 10.5%). Meanwhile, mcr-1, mcr-2, mcr-3, mcr-5, tet(X), tet(P), and tet(W) genes were not detected in all isolates. Class I and Class II integrons were detected in 92.3% (n = 24) and 65.4% (n = 17) isolates, respectively. About 31% (8 of the 26 isolates) isolates were carrying more than two resistance genes. According to our knowledge, this is the first study to detect class II integrons in Campylobacter spp. (C. jejuni). The high prevalence of cdtA, cdtB, cdtC, cadF, pldA, and ciaB genes and antibiotic resistance genes in C. jejuni in this study indicates the pathogenic potential of these isolates. Majority of the isolates demonstrated resistance to nalidixic acid, tetracycline (tet), and erythromycin (ermB), which are the drugs of choice for treating Campylobacter infections. Therefore, these findings highlight the importance of implementing an efficient strategy to control Campylobacter in chickens and to reduce antimicrobial use in the poultry industry, which will help to prevent the spread of infections to humans.

Molecular Detection of Integrons, Colistin and ß-lactamase Resistant Genes in Salmonella enterica Serovars Enteritidis and Typhimurium Isolated from Chickens and Rats Inhabiting Poultry Farms.

The rapid growth of multidrug-resistant Salmonella is a global public health concern. The aim of this study was to detect integrons, colistin and ß-lactamase resistance genes in Salmonella enteritidis and typhimurium. A total of 63 isolates of S. enteritidis (n = 18) and S. typhimurium (n = 45) from fecal samples of layers and rats at chicken farms were screened for antibiotic resistant genes. Conventional PCR was performed for the detection of integrons (classes 1, 2, and 3), colistin (mcr-1-5) and ß-lactamase (blaCTX-M, blaCTX-M-1, blaCTX-M-2, blaCTX-M-9, blaCTX-M-15, blaTEM, blaSHV, and blaOXA) resistant genes. Of these isolates, 77% and 27% of S. typhimurium and S. enteritidis harboured the mcr-4 encoded gene for colistin, respectively. The prevalence of class 1 integrons for S. typhimurium and S. enteritidis was 100% for each serovar, while for class 2 integrons of S. typhimurium and S. enteritidis it was 49% and 33% respectively, while class 3 integron genes was not detected. Our study also detected high levels of ß-lactamase encoding genes (bla gene), namely blaCTX-M, blaCTX-M-1, blaCTX-M-9 and blaTEM from both S. typhimurium and S. enteritidis. This, to our knowledge, is the first report of mcr-4 resistance gene detection in Salmonella serovars in South Africa. This study also highlights the importance of controlling rats at poultry farms in order to reduce the risk of transmission of antibiotic resistance to chickens and eventually to humans.

Isolation and antibiotic sensitivity of Campylobacter species from fecal samples of broiler chickens in North West Province, South Africa.

BACKGROUND AND AIM: Infections with Campylobacter species have gained recognition as the most frequent cause of foodborne gastroenteritis globally. Their significance in South Africa is still an area of study interest. This study was, therefore, carried out to determine the occurrence of Campylobacter species in chickens from North West Province of South Africa as well as their antibiotic sensitivity status. MATERIALS AND METHODS: A total of 2400 chicken fecal samples were collected and pooled to a total of 480 samples from five registered active poultry abattoirs in the Ngaka Modiri Molema District of North West Province, South Africa. Polymerase chain reaction (PCR) was used for the detection of Campylobacter spp. targeting the 16S rRNA gene while antibiotic sensitivity was determined using disk diffusion inhibition test. RESULTS: After isolation, a total of 26 samples were confirmed to be harboring Campylobacter jejuni by PCR and sequencing. C. jejuni was found to be the only isolate detected in all the fecal samples tested. The study further demonstrated that C. jejuni infections were highest in the summer season (3%) followed by autumn and winter at 1%, while there were none detected in the spring. The isolated C. jejuni-positive samples on disk diffusion inhibition test displayed resistance to nalidixic acid, tetracycline, erythromycin, and ciprofloxacin at 98%, 80%, 83%, and 21%, respectively. CONCLUSION: C. jejuni isolated in this study is known to cause disease in humans, and thus its occurrence requires application of "One Health" strategy to reduce the spread of this zoonotic pathogen in South Africa.