Escherichia coli Isolates’ Serotypes, Genotypes, and Virulence Genes and Clinical Coliform Mastitis Severity

Abstract

Dairy cattle with clinical mastitis caused by Escherichia coli exhibit a wide range of disease severity, from mild, with only local inflammatory changes of the mammary gland, to severe, with significant systemic derangement. The present study was designed to examine the relationship between serotype and virulence genes of E. coli mastitis isolates, different levels of systemic disease severity, and farm from which the E. coli strain was obtained. One hundred twenty-three E. coli milk isolates were obtained from cows with clinical mastitis of varying systemic disease severity from 6 different farms. No predominant serotype was identified by farm or by systemic disease severity; however, the most frequent serotype, O158:NM (n = 3), was isolated from cows in the moderate severity group. Virulence genes evaluated were identified infrequently and were not associated with systemic disease severity. Evaluation of genetic similarity showed no clustering assigned by farm or mastitis severity based on systemic disease signs. We concluded that a high degree of genotypic variability is characteristic of E. coli strains causing clinical mastitis within and between different farms and systemic severity groups, and that specific cow factors probably play a more important role in determining systemic disease severity.

Genetic heterogeneity of Escherichia coli isolated from pasteurized milk in State of Paraná, Brazil

“…These results indicate failures in pasteurization process or contamination in post-pasteurization processing and show the need for control measures to minimize E. coli contamination. The present results are consistent with Wenz et al (2006), who studied E. coli isolates from dairy cattle with mastitis, and Rantsiou, Alessandria and Cocolin (2012), who used ERIC-PCR to assess the genetic similarity of E. coli isolated from meat products and unpasteurized dairy products. E. coli is widely distributed in nature, and the sources of milk contamination can be diverse, explaining the high genotypic diversity observed in the present study.…”

“…Rantsiou, Alessandria and Cocolin (2012) assessed the genetic diversity of Shiga toxin-producing E. coli from meat and dairy products using ERIC-PCR. Wenz et al (2006) described genetic variability among E. coli isolates from dairy cattle with mastitis using ERIC-PCR. Ibenyassine et al (2006) used the same technique and evaluated the similarity of isolates from plants infected by irrigation water.…”

Distribution of serotypes and virulence-associated genes in pathogenicEscherichia coliisolated from ducks

“…The serogroups of STEC identified in the present study were shown to be O36, O60, O77, O78, O158 and O78&O92, among which O77 had been detected in STEC of cattle and sheep (Blanco et al, 2003), and STEC O78 had been found in humans, sheep, pigs and birds, and it was also the predominant serogroup of APEC (Fratamico et al, 2004;Shaheen et al, 2004). O158 has also been found in STEC strains isolated from cattle and sheep (Fratamico et al, 2004;Wenz et al, 2006). Thus, it is suggested that the STEC isolates detected in the present study may have wide host sources.…”

Akut Sığır Mastitislerinden İzole Edilen Escherichia coli Suslarının Filogruplandırılması ve Virulens Faktör Değerlendirmesi

“…Clinical signs of E. coli mastitis differ from severe or even fatal forms to mild mastitis. Association between the virulence factors of the isolate and the clinical severity of mastitis has not been clarified, yet [3] .…”

“…Escherichia coli is the most common pathogen of acute bovine mastitis worldwide [1][2][3] . Clinical signs of E. coli mastitis differ from severe or even fatal forms to mild mastitis.…”