Bovine mastitis is a common worldwide infection caused by different types of pathogens
including coliform bacteria. Understanding mastitis pathogens and their dominance, as well
as risk factors, is required to facilitate disease prevention and control, and to enhance udder
health within the herd. Our objectives were to investigate the prevalence of different mastitis-
causing pathogens and describe some genetic traits which outline mastitis-associated E.coli
(MAEC). Four-hundred twenty-eight quarter foremilk samples were collected from 107
apparently healthy lactating cows and buffaloes from El-Menofia Governorate between 2020-
2022. The California Mastitis Test (CMT) was used to estimate the quarter somatic cell count
(SCC), with subclinical mastitis (SCM) defined as non-negative CMT score. The bacterial
culture of milk was used as a reference method to identify SCM based on the isolation of the
causative pathogens. VITEK-2 compact system was used for isolates identification.
Serological identification of E.coli serotypes and molecular identification of some virulence
genes using PCR were also performed. The prevalence of SCM was 60.7% with E.coli being
the most commonly isolated organism. The enteropathogenic serotypes of E.coli isolated
from the examined milk samples showed; O26:H11 (EHEC) 21.70%, O15:H2 (ETEC) 13.04%,
O127:H6 (ETEC) 4.34%, O121:H7 (EHEC) 13.04%, O117:H4 (EHEC) 17.39%, O146:H21 (EPEC)
17.39% and O103:H2 (EHEC) 13.04%. The molecular identification of the most common
virulence genes of E.coli revealed the presence of sfa, papC, and traT genes in 100% of the
examined samples while cnf1 gene was present in only 30% of the samples |
