Molecular characterization of antimicrobial resistance and virulence genes of Escherichia coli isolates from bovine mastitis

Abstract

Background and Aim: Mastitis is a common and economically important disease in dairy cattle. It remains one of the most common reasons for the extensive use of antimicrobials in dairy farms leading to the emergence of antimicrobial-resistant pathogens. The aim of this study was to determine the patterns of antimicrobial resistance of Escherichia coli isolates from bovine mastitis and to identify prominent antimicrobial resistance and virulence genes among isolated strains. Materials and Methods: Antimicrobial susceptibility testing against six antibiotic groups, including tetracyclines, aminoglycosides, beta-lactams, macrolides, sulfonamides, and fluoroquinolones was performed using the disk diffusion method. PCR was performed on resistant isolates to detect resistance and virulence genes using commercially available primers. Results: Out of 216 milk samples cultured, 14 samples yielded E. coli isolates. All isolates (100%) were resistant to ampicillin, amoxicillin, procaine penicillin, streptomycin, oxytetracycline, and sulfamethoxazole-trimethoprim. Only one isolate (7%) was sensitive to gentamicin, and all isolates (100%) were sensitive to enrofloxacin and ciprofloxacin. All isolates carried at least one resistance gene against one or more of the major antibiotic groups. All isolates carried the ereA, tetG, tetE, and tetB genes, followed by tetA (93%), ampC (86%), strA (86%), sul1 (78%), tetD (71%), tetC (57%), aadA (57%), and strB (36%). The lowest percentage of isolates carried bla1 (17%) and bla2 (12%) genes, and none of the isolates carried the qnrA gene. Most of the isolates (93%) carried the Shiga toxin 1 virulence gene, followed by complement resistance protein (79%), intimin (64%), Shiga toxin 2 (36%), cytotoxic necrotizing factor (35%), aerotaxis receptor (21%), and type 1 fimbriae (15%). Conclusion: Results of this study indicate that the high percentages of E. coli isolate from bovine mastitis are resistant to two or more of the major antibiotic groups, irrespective of the presence or absence of relevant resistance or virulence genes.

Multidrug-resistant Escherichia coli in Raw Milk: Molecular Characterization and the potential impact of camel’s Urine as an Antibacterial Agent

“…There are many studies in the field of animal products that have suggested that the repeated use of antibiotics has increased the prevalence of different bacterial strains that carry many highly pathogenic genes against the many antibiotics used to treat these bacteria ( Srinivasan et al, 2007 ). Consequently, truthful identification, careful usage of antibiotics, and the application of an effective antimicrobial drug to treat the various contagious illnesses should be applied to restrict the development and distribution of multidrug-resistant microorganisms among animals and humans ( Ismail and Abutarbush, 2020 ).…”

“…The development of multi-drug resistant E. coli strains recovered from mastitic milk and clinical samples is considered a public health alarm worldwide ( Kahlmeter and Poulsen, 2012 , Copur-Cicek et al, 2014 ). Previous scientific reports have proven that there is a close correlation between the amazing development of multidrug-resistant E. coli strains from different animals and those from human clinical samples ( Rasheed et al, 2014 , Walther et al, 2017 , Ismail and Abutarbush, 2020 ).…”

“…( Oliver et al, 2005 , Hennekinne et al, 2012 ), particularly via the ingestion of unpasteurized milk ( Gillespie et al, 2009 ). There are many microorganisms that cause mastitis in cows and the bacterium E. coli represents one of the significant reasons for symptomatic and asymptomatic mastitis among dairy farms ( Burvenich et al, 2003 , Abebe et al, 2014 , Bedasa et al, 2018 , Ismail and Abutarbush, 2020 ). The Gram-negative E. coli is rod-shaped bacterium that frequently established in the human’s intestine and animals.…”

“…The Gram-negative E. coli is rod-shaped bacterium that frequently established in the human’s intestine and animals. However, the majority of E. coli strains are safe, certain strains, for instance, E. coli strains that produce Shiga toxins, has the competence to cause foodborne illnesses ( Dhaka et al, 2016 , Wang et al, 2016 , Ismail and Abutarbush, 2020 ). Predominantly, this germ is transferred to human beings via ingesting adulterated food, such as unpasteurized milk and dairy products ( Bali et al, 2013 ).…”

Lacaune ewes with subclinical mastitis: effects of intramammary application of própolis

“…According to Farshad et al (2012), the presence of this microorganism in raw milk and dairy products is serious, as it can cause diseases such as uremic hemolytic syndrome, hemorrhagic colitis, and bloody diarrhea; this is why we seek to reduce bacterial contamination of milk to the greatest extent possible. In a recent study with cattle, 14 isolates from milk were identified as E. coli (Ismail & Abutarbush, 2020), a zoonotic bacterium that needs to be under constant surveillance.…”