Prevalence of adhesin and toxin genes among isolates of Staphylococcus aureus obtained from mastitic cattle

Abstract

Staphylococcus aureus is recognized as a major etiological agent of the most important udder disease; mastitis. The virulence potential of S. aureus isolates is attributed to a combination of extracellular factors and invasive properties that are controlled at the genomic level. In this study molecular variations were studied among the 128 S. aureus isolates obtained from the mastitic crossbred cattle. The polymorphic patterns of protein A, coagulase, and IG genes were studied in the isolates using the PCR and PCR-RFLP methods. In addition, presence of other virulence genes responsible for the expression of adhesins and toxins was also screened. A considerable genetic variation was observed in amplified fragment of SPA, IG and CLF genes. The PCR-RFLP of COA gene yielded five different patterns. Occurrence of EBP, ENO and FNBA was found to be common in both high and low virulence isolates. However, the prevalence of FNBB and toxin genes was higher in clinical than subclinical isolates. The distribution proportions of adhesin genes EBP, FIB, FNBB, CNA, BBP, MAP CAP5, and CAP8 were 60.2, 59.4, 21.9, 6.3, 5.5, 80.5, 56.3, and 22.7%; for AGR I, II, III, and IV were 44.5, 32.8, 12.5, and 10.2%; and for toxins genes HLB, SEB, SEC, SED, SEE, SEG, and SEI were 82.0, 3.1, 5.5, 3.9, 0.8, 16.4, and 55.5%, respectively. The proportions of FNBB, EBP, FIB, HLB, BBP, SEG, and SEI genes were observed more in clinical cases. The significant genetic variations in SPA, COA, IG, and CLF genes were useful to differentiate the isolates that might be valuable for mastitis reduction programme.

Genes encoding adhesion factors and biofilm formation in methicillin-resistant Staphylococcus aureus in Morocco

“…As for the fib gene, we detected it at a rate of 5.66% in our study. Elastin is the major component of elastic fibers, which are proteins that provide strength and flexibility to connective tissue [32]; we verified the presence of ebpS gene in 9.34% of our isolates.…”

“…Fibrinogen plays an important role in the blood coagulation process, in which fibrinogen is transformed into its insoluble form, fibrin. The fibrinogen-binding protein is an important virulence factor in infections caused by Staphylococcus aureus, as it not only binds to fibrinogen, but can also interfere with the aggregation of platelets and the complement cascade within the host [31][32][33]. As for the fib gene, we detected it at a rate of 5.66% in our study.…”

Fatores de virulência de Staphylococcus spp. e viabilidade celular na mastite subclínica de cabras

“…Dessa forma, a expressão da proteína de superfície provavelmente contribui para a colonização de S. aureus através da ligação à laminina presente na matriz extracelular, ativação do plasminogênio e degradação da laminina em áreas restritas, favorecendo a invasão e a disseminação do microrganismo (CARNEIRO et al, 2004). O gene eno foi um dos mais detectados em mastites por S. aureus e por SCN (KUMAR et al, 2011b;SIMOJOKI et al, 2012).…”

“…Salasia et al 2004 (KUMAR et al, 2011a;SIMOJOKI et al, 2012;ALMEIDA et al, 2013). Em contrapartida, Ikawaty et al (2010) e Kumar et al (2011b) encontraram esse gene em 49% e 6,3% de um total de 76 e 128 isolados de S. aureus, respectivamente. Embora esse gene exerça um relevante papel em processos infecciosos ósseos, a sua presença em infecções da glândula mamária pode não ser tão importante (ELASRI et al, 2002;KLEIN et al, 2012) -GARAYZÁBAL, 1999;CONTRERAS et al, 2003; e também não foi realizada pesquisas sobre os genes de fatores de virulência que podem acometer essa espécie de estafilococos.…”

“…). A baixa ocorrência de gene bap nos SCP, em relação aos SCN, pode ser um indicativo de que os SCN tenham mais capacidade de formar biofilme enquanto os SCP possuam outras características de virulência, o que justifica os genes ebpS, fib e fnbA terem sido mais detectados nos SCP e o bap e eno serem mais detectados nos SCN.Mas os estudos sobre isso ainda são escassos e, portanto, mais pesquisas devem ser realizadas sobre os genes de fatores de virulência e as espécies de estafilococos.Adicionando-se ao que foi descrito anteriormente, pôde-se observar que as associações que mais ocorreram em SCN e SCP foram, respectivamente, bap/eno e ebpS/eno/fib/fnbA Kumar et al (2011b). encontraram muitas associações em S. aureus, já nos SCN, não há informações na literatura.…”