Analysis of Escherichia coli isolated from bovine mastitic milk

Abstract

RESUMO.-[Análise de Escherichia coli isolada de leite de vacas com mastite.]A um longo tempo a mastite tem sido reconhecida como a doença que provoca as maiores perdas econômicas nos rebanhos leiteiros. De fevereiro a novembro de 2004, foram coletadas 670 amostras de leite mastítico de vacas, provenientes de dois estados brasileiros, das quais foram isoladas 231 cepas de Escherichia coli. Estas cepas foram analisadas para a detecção dos genes de produção de Shiga toxina (stx 1 e stx 2) e do gene da intimina (eae). Vinte cepas (8,6%) foram detectadas através de PCR como contendo os genes da Shiga toxina (8 stx 1, 12 stx 2 e nenhuma delas ambos os genes). Duas cepas (0,8%) de E. coli eram eae positivo não produtoras de Shiga toxina. As cepas de E. coli foram também examinadas para detectar a resistên-cia a 12 agentes antimicrobianos. As resistências mais freqüentes foram para tetraciclina (92,2%), estreptomicina (90,4%), ácido nalidixico (88,3%), amicacina (86,5%) e cefalotina (84,8%). A resistência a múltiplas drogas foi encontrada em 152 cepas (65,8%). TERMOS DE INDEXAÇÃO:Escherichia coli, mastite, agentes antimicrobianos, resistência a múltiplas drogas, STEC, gene eae. INTRODUCTIONMastitis remains a major cause of financial loss to the dairy industry and is considered to be economically the most important disease of dairy cattle (Hortet & Seegers 1998 Escherichia coli strains were isolated, were collected from two Brazilian states. The strains were screened for the presence of Shiga toxin-producing (stx 1 and stx 2) and intimin (eae) genes. Twenty (8.6%) strains were detected by PCR to harbor the Shiga toxin genes (8 the stx 1 gene, 12 the stx 2 gene and none both of them). Two (0.8%) of the Escherichia coli strains studied were eae positive non Shiga toxin-producing. The strains were also examined for resistance to 12 antimicrobial agents. The predominantly observed resistance was to tetracycline (92.2%), streptomycin (90.4%), nalidixic acid (88.3%), amikacin (86.5%) and cephalothin (84.8%). Multidrug resistance was found among 152 isolates (65.8%).

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

“…Heterogeneous profiles of antimicrobial resistance were also described by Rangel and Marin (2009) and Solomakos et al (2009) …”

A contribution on Coliforms causing mastitis in cows with reference to serotypes and virulence factors of E. coli isolates

“…Mastitis is an important and a persistent infection producing high economies losses due to poor milk quality, reduced milk yield and increased expenditure on treatment especially staphylococcal mastitis [16] which resembled 63.37% through the current study and bacteriological examination shows that S. aureus was the main causative agent of clinical mastitis in cows [34 [17]; [18]; [19] , respectively. However, the findings [71.4%] of S. aureus by [20] are much higher than the present report.…”

“…Slime synthesis is controlled by the ica [intercellular adhesion] operon. Coexpression of icaA with icaD leads to a significant increase in activity and is related to phenotypic expression of the capsular polysaccharide [34] . In this study, slime factor production of MRSA isolates were detected by PCR targeting icaA and icaD genes and found that 5 [4] .…”

Detection of Several Virulence Properties, Antibiotic Resistance and Phylogenetic Relationship in E. Coli Isolates Originated from Cow Mastitis

“…In the current study, stx1, stx2, and intimin genes were evaluated. In the previous studies, researchers also stated variations in the presence rates for these genes [5,20,21,22]. Although, Momtaz et al (2012) and Kobori et al (2004) stated a higher presence rate, other researchers [18,23,24] could not detect the gene in E. coli strains.…”

“…E. coli is an environmental mastitis pathogen, which causes clinical signs in mammary glands in cows and its resistance against antibiotics depends on herd management. In previous studies, various antibiotic resistance profi les and rates in E. coli strains were stated in previous studies especially for oxytetracycline [29,30,31,32], penicillin [22,32,33,34], macrolides [21,35,36], trimethoprimsulphamethoxazole [6,36,37], fl uoroquinolones [35,36] and cephalosporins [38]. In the presented papers, resistance profi les of E. coli strains were evaluated for vancomycine, danofl oxacin, oxytetracyline, enrofl oxacin, amoxicillin-clavulanic acid, trimethoprim-sulphamethoxazole, ampicillin and tetracycline.…”