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Leishmania (L.) infantum-infected dogs may present with a large range of clinical signs, from apparently healthy with no or few (asymptomatic dogs, AD) to several clinical signs indicators of active infection (symptomatic dogs, SD). The present study is justified by the conflicting reports describing that either L. infantum-specific IgG1 or IgG2 antibodies may be used as isotype marker of the asymptomatic infection status and by the lack, to our knowledge, of previous analysis of the IgG sub-classes autoantibody repertoires of Leishmania-infected dogs. On the basis of clinical evaluation and laboratory testing (IFAT, parasitological examination of Giemsa-stained lymph node smears, L. infantum antigens-ELISA of total (Tot) IgG), 131 dogs were categorized as SD, asymptomatic seronegative (AND) or seropositive dogs (APD) from surrounding areas, and as negative control dogs (CTD). ELISA based on leishmanial native antigens or recombinant LACK and LeIF proteins showed that SD produce higher levels of specific Tot IgG, IgG1 and IgG2 antibodies than APD, and that for both clinical stages, the antibody titers of IgG2 isotype were constantly higher than those of the IgG1. The seroprevalences of Tot IgG, IgG2 did not differ between APD and SD groups (97 and 97% in SD; 100 and 96% in APD, respectively) whereas that of IgG1 was slightly lower in SD (88% of APD versus 82% of SD). The autoantibody repertoires were analyzed by ELISA using HEp-2 extracts, ds-DNA, human albumin and transferrin as self-antigens and by Western blot using HEp-2 proteins. ELISA results' indicated that APD develop higher levels of IgG1 autoantibodies, and higher seroprevalence (50% and 26% in APD and SD, respectively), contrasting with lower levels and seroprevalences of Tot IgG and IgG2 (43 and 68% for APD; 100 and 74% for SD). Interestingly, SD showed a stronger IgG1 and particularly IgG2 reactivity with transferrin, an iron-binding protein, than APD and AND. Western blotting experiments produced heterogeneous IgG1 and IgG2 inter- and intra-groups reactivity profiles towards HEp-2 proteins, to identify a specific antigenic profile. Generated data from competitive HEp-2-ELISA using leishmanial antigens as inhibitors were in favor that IgG1 antibodies are predominantly autoantibodies to self-antigens in APD whereas they are mainly cross-reactive (Leishmania/self-antigens) in SD.

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Background: Escherichia coli (E. coli) is one of the main etiological agents responsible for bovine mastitis (BM), neonatal calf diarrhea (NCD), and avian colibacillosis (AC). This study aimed to assess resistance and virulence genes content, biofilm-forming ability, phylogenetic groups, and genetic relatedness in E. coli isolates recovered from clinical cases of BM, NCD, and AC. Materials/Methods: A total of 120 samples including samples of milk (n =70) and feces (n =50) from cows with BM and calves with NCD, respectively, were collected from different farms in Northern Tunisia. Bacterial isolation and identification were performed. Then, E. coli isolates were examined by disk diffusion and broth microdilution method for their antimicrobial susceptibility and biofilm-forming ability. PCR was used to detect antimicrobial resistance genes (ARGs), virulence genes (VGs), phylogenetic groups, and Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) for their clonal relationship. Results: Among the 120 samples, 67 E. coli isolates (25 from BM, 22 from AC, and 20 from NCD) were collected. Overall, 83.6% of isolates were multidrug resistant. Thirty-six (53.73%) isolates were phenotypically colistin-resistant (CREC), 28.3% (19/67) were ESBL producers (ESBL-EC), and forty-nine (73.1%) formed biofilm. The blaTEM gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the blaCTXM-g-1 gene was detected in 47.3% (9/19) of isolates, all from AC. The most common VG was the fimA gene (26/36, 72.2%), followed by aer (12/36, 33.3%), cnf1 (6/36, 16.6%), papC (4/36, 11.1%), and stx1 and stx2 genes (2/36; 5.5% for each). Phylogenetic analysis showed that isolates belonged to three groups: A (20/36; 55.5%), B2 (7/36; 19.4%), and D (6/36; 16.6%). Molecular typing by ERIC-PCR showed high genetic diversity of CREC and ESBL E. coli isolates from the three animal diseases and gave evidence of their clonal dissemination within farms in Tunisia. Conclusion: The present study sheds new light on the biofilm-forming ability and clonality within CREC and ESBL-EC isolated from three different animal diseases in Tunisian farm animals.