The phylogenetic group, antimicrobial susceptibility, and virulence genes of Escherichia coli from clinical bovine mastitis

Abstract

Bovine mastitis is still a central problem on dairy farms despite control programs, and Escherichia coli is a crucial pathogen during the development of bovine mastitis. The virulence genes, antimicrobial susceptibility, and mortality of mice infected with different E. coli isolates from bovine mastitis were determined in this study. According to the presence of the specific genes chuA, yjaA, and TspE4.C2, these isolates mainly belonged to 2 different groups: group A (47/79) and group B1 (22/79). The ompC gene was detected in all the isolates, followed by fimH (89.9%), ECs3703 (88.6%), and ompF (73.4%), whereas most of the virulence genes were not detected in these isolates. The results of the antimicrobial susceptibility tests indicated that the isolates were susceptible to the fluoroquinolones and aminoglycosides. An inverse relationship was shown between the expression level of ompF and antimicrobial resistance; additionally, the isolates that were nonsusceptible to at least 4 classes of antimicrobial agents showed a lower mortality to mice in comparison with the susceptible isolates. This study indicated that antibiotic resistance had emerged in E. coli from bovine mastitis in this area, and appropriate measures should be taken to avoid potential threats to humans and other animals.

Putative virulence factors of extra‐intestinalEscherichia coliisolated from bovine mastitis with different clinical scores

“…However, only 10Á0% of the isolates were classified as pathogenic phylogroups B2 (6Á0%) and D (4Á0%) (Clermont et al 2011). This finding is in accordance with previous studies that evaluated E. coli isolates phylogenetically from intramammary infections in dairy cattle and predominantly classified strains as commensal or opportunistic pathogens both for humans and domestic animals (Burvenich et al 2003;Fernandes et al 2011;Suojala et al 2011;Blum and Leitner 2013;Zhang et al 2018). Thus, due the lack of association between the specific VFs and the clinical manifestations, the pathogenic actions of E. coli have been partially attributed to concurrent immunosuppressive factors (i.e.…”

“…; Blum and Leitner ; Zhang et al . ). Thus, due the lack of association between the specific VFs and the clinical manifestations, the pathogenic actions of E. coli have been partially attributed to concurrent immunosuppressive factors (i.e.…”

Antimicrobial susceptibility, phylotypes, and virulence genes of Escherichia coli from clinical bovine mastitis in five provinces of China

“…(18.5%) in 497 raw milk samples. The prevalence of E. coli isolates was higher in our study than in a study performed in Turkey (3.2%, 8/250) (Akkaya, Cetinkaya, Alisarli, Telli, & Gök, 2008) and in Liaoning province, China (20.1%,79/389) (Zhang et al, 2018). Our results revealed that E. coli is prevalent in raw milk from mastitic cows in all five regions of China.…”

“…Bovine mastitis, which affects dairy farms throughout the world, reduces milk production, negatively impacts milk quality, and represents a source of contamination for raw milk and dairy products (Halasa, Huijps, Østerås, & Hogeveen, 2007). Several bacteria cause mastitis in dairy cows, including Escherichia coli (Olde Riekerink, Barkema, Scholl, Poole, & Kelton, 2010), one of the most predominant pathogens (Zhang et al, 2018), Staphylococcus aureus (Olde Riekerink, Barkema, Kelton, & Scholl, 2008), and Streptococcus uberis (Levison et al, 2016). E. coli, which has an isolation rate of 10.2% in bovine mastitis (Tenhagen, Hansen, Reinecke, Heuwieser, & Lam, 2009), can be classified into pathogenic and nonpathogenic bacteria, and pathogenic bacteria can be further classified into different types based on the pathogenic mechanism (Blum & Leitner, 2013)and virulence factor, such as enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), Shiga toxin-producing E. coli (STEC or VTEC), and enterohemorrhagic E. coli (EHEC (Fitzhenry et al, 2002;Nagy & Fekete, 1999)).…”

“…Multidrug-resistant E. coli strains, which represent a significant public concern (Erb, Sturmer, Marre, & Brenner, 2007;Johnson et al, 2008), have been isolated from animals in several countries including China (Rao et al, 2014;Seni et al, 2016;Xu, An, Wang, & Zhang, 2015). Additionally, several virulence factors associated with E. coli infections and various pathogenic bacterial genes have been isolated from mastitis in dairy cows (Zhang et al, 2018). Virulence genes identified in E. coli from bovine mastitis include genes that code for hemagglutinin, aerobactin, P-fimbria, enterohemolysin, intimin, and autoagglutinating adhesion proteins (Bekal et al, 2003;Ewers et al, 2007;Johnson et al, 2008).…”