Molecular identification of diarrheagenic Escherichia coli pathotypes and their antibiotic resistance patterns among diarrheic children and in contact calves in Bahir Dar city, Northwest Ethiopia

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.

Molecular detection and antibiogram of Shiga toxin-producing Escherichia coli (STEC) from raw milk in and around Bahir Dar town dairy farms, Ethiopia

“…In the present study, E. coli isolates were found sensitive to ciprofloxacin (94.7%), kanamycin (89.5%), and chloramphenicol (84.2%). This sensitivity result agrees with the findings of Belete et al [ 24 ] and Dejene et al [ 15 ]. However, isolates were found resistant to amoxicillin (89.5%), in line with 64.9% resistance in a study conducted by Belete et al [ 24 ] in Bahir Dar town.…”

“…Dairy production is practiced in and around the town, supporting the livelihood of the inhabitants of Bahir Dar. The mean annual rainfall of the city is about 596 mm, with a bimodal rainy season distribution of 70%, which occurs from June to September and 30% from March to April [ 24 ].

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“…The PCR assays were performed using four specific primers ( Table 1 ), targeting the stx1 , stx2 , eae , and ribo157 genes as previously described [ 24 , 28 ]. The DNA was extracted using a Qiagen DNeasy Blood and Tissue Kit based on the manufacturer's instructions (Qiagen, Germantown, MD, USA).…”

“…Mueller Hinton (MHA) agar media (Oxoid, England) and a 0.5 Mac-Farland standard suspension of the bacteria were prepared to culture and adjust the density of the bacterial suspension, respectively. The result of the zone of inhibition was measured and interpreted as sensitive, intermediate, or resistant according to the Clinical and Laboratory Standards Institute (CLSI) guidelines [ 24 ].…”

Isolation and characterization of lytic bacteriophages from various sources in Addis Ababa against antimicrobial-resistant diarrheagenic Escherichia coli strains and evaluation of their therapeutic Potential

“…AMR among pathogenic E. coli strains are steadily increasing in Ethiopia [7,21]. Despite the growing threat of antimicrobial resistance in our country, little attention is given to its management, and novel alternatives have yet to be explored.…”