ABSTRACT
Background and Purpose: Staphylococcus aureus is a common pathogen responsible for causing various human and animal infections and is well known for its ability to develop resistance to multiple antibiotics. This study aimed to evaluate the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in bulk milk and dairy farms in northwestern Ethiopia and to determine their phenotypic and genotypic antimicrobial susceptibility patterns. Methods: We collected 50 bulk milk samples from 50 dairy farms and 50 hand swabs from dairy milkers. The cefoxitin disk diffusion test and PCR-based assays were used to identify MRSA isolates. In addition, cefoxitin-resistant isolates were tested for susceptibility to other antibiotics using the Kirby-Bauer disk diffusion method. Results: The results showed that MRSA was detected in 8 samples: 6 from bulk milk samples (12%) and 2 from hand swabs (4%). All MRSA isolates exhibited a high resistance rate to penicillin (100%), followed by tetracycline (75%), ciprofloxacin (25%), chloramphenicol (25%), erythromycin (25%), gentamycin (12.5%), and trimethoprim-sulfamethoxazole (12.5%). Moreover, 72% of the isolates showed resistance to three or more antibiotic classes and were classified as multidrug-resistant. Conclusion: This study identified methicillin-resistant Staphylococcus aureus and multidrug-resistant MRSA in bulk milk and dairy farms in northwestern Ethiopia. These findings highlight the potential risk of transmission of these antibiotic-resistant bacteria to humans and the need for improved antibiotic stewardship in the dairy sector using the One Health approach.
ABSTRACT
Diarrheagenic Escherichia coli (DEC) are the leading cause of infectious diarrhea and pose a significant global, regional, and national burden of disease. This study aimed to investigate the prevalence of six DEC pathotypes in children with diarrhea and determine their antibiotic resistance patterns. Samples from 107 diarrheagenic children were collected and processed for Escherichia coli (E. coli). Single-plex PCR was used to detect target virulence genes as well as characterize and categorize DEC pathotypes. Antibiotic resistance patterns were determined by the Kirby-Bauer disk diffusion method. E. coli was detected in 79 diarrheal stool samples, accounting for 73.8% of the samples collected. Additionally, 49.4% (39 out of 79) of the isolates harbored various typical virulence factors. Results revealed six pathotypes of virulence: enterotoxigenic E. coli (ETEC) (53.8%), enteropathogenic E. coli (EPEC) (12.8%), enteroaggregative E. coli (EAEC) (10.3%), Heteropathotypes (7.8%), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC) (7.7% each). The isolates exhibited high antibiotic resistance against trimethoprim/sulfamethoxazole (82.1%), amoxicillin (79.5%), ampicillin (74.4%), gentamicin (69.2%), and streptomycin (64.1%). An overall occurrence of 84.6% of multiple-drug resistance was observed in the isolates, with resistance ranging from three to four antibiotic classes. Our findings revealed a high level of pathogenic E. coli that were highly resistant to multiple categories of antibiotics among children in the Awi zone. These findings highlight the potential role of pathogenic E. coli in childhood diarrhea in tropical low-resource settings and underscore the need for continued research on the characteristics of pathogenic and antibiotic-resistant strains.
ABSTRACT
Diarrheagenic Escherichia coli strains are an essential cause of diarrheal infection in younger children and animals. The study was focused on understanding the associated characteristics of various DEC strains among children and calves, establishing the possible zoonotic transmission, and determining their antibiotic resistance patterns. Samples from 144 acute diarrheic children and 50 diarrheic calves were collected and processed using traditional culture methods. The molecular identification of pathotypes was completed using primer-specific polymerase chain reaction (PCR) targeting ten virulence genes (stx1, stx2, eae, aatA, lt, st, ial, hlyA bfpA, and daaE) related to six DEC pathotypes (EPEC, ETEC, EHEC, EAEC EIEC, and DAEC). The antimicrobial susceptibility testing was carried out using the Kirby-Bauer disk diffusion method. Colonies from 74 study subjects (54 diarrheic children and 20 diarrheic calves) were positive for E. coli isolates. Subsequent PCR detection discovered that 77% of children and 85% of calves' isolates were positive for one or more virulence genes typical of particular strains. Among those ETEC [(18%), (26%)] is being the maximum predominant, and [(15%), (15%)] were positive for STEC, [(13%), (8%)] for atypical EPEC, [(6%), (7%)] for EHEC, [(6%), (5%)] for EAEC, and [(6%), (4%)] for EIEC strains in children's and calves, respectively. Of the identified E. coli isolates, about 29% were found to be hybrid isolates. ETEC (66.7%) and STEC (58.9%) strains showed a better detection rate in contact children with diarrheic calves than children with no contacts. Most antibiotic resistances were obtained towards amoxicillin (64.9%), gentamycin (56.8%), and ampicillin (54.1%). Up to sixty-five percent of isolates were resistant to a minimum of three categories of antibiotics. This is the primary report on the wide occurrence of the six-diarrheagenic Escherichia coli strains, and ETEC was found to be the predominant pathotype among children and contact calves in Ethiopia.
