Prevalence of Clostridium sPP. in diarrhoeic and healthy dogs ...
Prevalence of Clostridium sPP. in diarrhoeic and healthy dogs ...
Prevalence of Clostridium sPP. in diarrhoeic and healthy dogs ...
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Ann. Fac. Medic. Vet. di Parma (Vol. XXVII, 2007) pag. 143 - pag. 156different (P= 0.023, Fisher’s test). This is <strong>in</strong> disagreement with previous reports <strong>in</strong>which significant differences were not found <strong>in</strong> the isolation rates <strong>of</strong> C. difficilebetween the 2 groups [3]. Four <strong>of</strong> ten C. difficile-positive <strong>dogs</strong> expressed enteritisafter antibiotic therapy. Probably, antibiotic adm<strong>in</strong>istration caused the overgrowth<strong>of</strong> C. difficile <strong>in</strong> <strong>in</strong>test<strong>in</strong>e <strong>of</strong> the <strong>dogs</strong>, predispos<strong>in</strong>g the animals to enteritis. Infact, a previous study has reported that the carriage rate <strong>of</strong> C. difficile <strong>and</strong> tox<strong>in</strong>s<strong>in</strong> animals <strong>in</strong>clud<strong>in</strong>g <strong>dogs</strong> that had recently received antibiotics was higher than<strong>in</strong> the nonantibiotic-treated group, although these differences were not statisticallysignificant [3]. Another study has <strong>in</strong>dicated that the presence <strong>of</strong> C. difficile <strong>in</strong> can<strong>in</strong>efeces was evident only after adm<strong>in</strong>istration <strong>of</strong> antibiotic [9]. However, results <strong>of</strong>several studies have supported the notion that antimicrobial treatment is not requiredfor C. difficile-associated disease (CDAD) development <strong>in</strong> <strong>dogs</strong> [3].S<strong>in</strong>ce we did not research the tox<strong>in</strong>s A <strong>and</strong> B (neither <strong>in</strong> vivo directly <strong>in</strong> fecesnor <strong>in</strong> vitro from the C. difficile isolates), which seem the primary virulence factors<strong>in</strong>volved <strong>in</strong> the pathogenesis <strong>of</strong> CDAD, we cannot correlate the C. difficile isolationwith dog illness. However, we performed on the 10 C. difficile isolates a duplexPCR for the revelation <strong>of</strong> tcdA <strong>and</strong> tcdB genes, encod<strong>in</strong>g for tox<strong>in</strong> A <strong>and</strong> tox<strong>in</strong> B,respectively [11]. The majority <strong>of</strong> C. difficile stra<strong>in</strong>s (6/10, 60.0%) were toxigenic(tcdA+/tcdB+) on the basis <strong>of</strong> the results <strong>of</strong> PCR assay (data not shown). The carriagerates <strong>of</strong> toxigenic isolates <strong>in</strong> <strong>diarrhoeic</strong> <strong>dogs</strong> (5/6, 83.3%) were higher than those<strong>in</strong> non-<strong>diarrhoeic</strong> <strong>dogs</strong> (1/6, 16.7%). However, this difference was not statisticallysignificant (P= 0.08, Fisher’s test).It could be <strong>in</strong>terest<strong>in</strong>g to verify if tcdA/tcdB-positive stra<strong>in</strong>s by PCR willbe able to produce the two tox<strong>in</strong>s also <strong>in</strong> vitro, because the presence <strong>of</strong> genes is notalways correlated with their expression.ConclusionsIt is particularly important to seek C. perfr<strong>in</strong>gens <strong>and</strong> C. difficile presence<strong>in</strong> can<strong>in</strong>e fecal samples. However, C. perfr<strong>in</strong>gens-associated diarrhoea <strong>in</strong> the <strong>dogs</strong>eems to be a complex disease, the pathogenesis <strong>of</strong> which is still poorly understood.Furthermore, despite various reports that have documented an association betweenthe detection <strong>of</strong> CPE <strong>and</strong> the presence <strong>of</strong> diarrhoea, it is still unclear whether or notC. perfr<strong>in</strong>gens is a primary cause <strong>of</strong> can<strong>in</strong>e diarrhoea or a secondary determ<strong>in</strong>ant.Much work still needs to be done to clarify the exact role <strong>of</strong> C. perfr<strong>in</strong>gens <strong>in</strong>can<strong>in</strong>e diarrhoea. Based on the results <strong>of</strong> several studies, the optimum diagnosticapproach for can<strong>in</strong>e C. perfr<strong>in</strong>gens-associated diarrhoea is the use <strong>of</strong> a CPE ELISA<strong>in</strong> conjunction with PCR for detection <strong>of</strong> enterotoxigenic stra<strong>in</strong>s procured aftera heat shock or alcohol shock treatment [7]. To date, different PCRs (duplex <strong>and</strong>multiplex) were evaluated for the revelation <strong>of</strong> genes encod<strong>in</strong>g for C. perfr<strong>in</strong>genstox<strong>in</strong>s (CPE, tox<strong>in</strong> α, tox<strong>in</strong> β, tox<strong>in</strong> β2, tox<strong>in</strong> ι <strong>and</strong> tox<strong>in</strong> ε) only for research purposes[2, 4]. It will be useful to evaluate these methods on our isolates for the presence <strong>of</strong>C. perfr<strong>in</strong>gens tox<strong>in</strong> genes, especially <strong>of</strong> the CPE gene. The production <strong>in</strong> vivo <strong>and</strong>/or<strong>in</strong> vitro <strong>of</strong> CPE should be also <strong>in</strong>vestigated to correlate the C. perfr<strong>in</strong>gens isolationwith diarrhoea <strong>in</strong> <strong>dogs</strong>.153