This study sought to evaluate the probiotic properties and the food preservation ability of lactic acid bacteria isolates collected from the intestines of wild marine fishes (gilthead seabream (Sparus aurata) (n = 60) and whiting fish (Merlangius merlangus) (n = 40)) from the Mediterranean sea in the area of Mostaganem city, Algeria. Forty-two isolates were identified as: Enterococcus durans (n = 19), Enterococcus faecium (n = 15), Enterococcus faecalis (n = 4), Lactococcus lactis subp. lactis (n = 3), and Lactobacillus plantarum (n = 1). All isolates showed inhibition to at least one indicator strain, especially against Listeria monocytogenes, Staphylococcus aureus, Paenibacillus larvae, Vibrio alginolyticus, Enterococcus faecalis, Bacillus cereus, and Bacillus subtilis. In all collected isolates, PCR analysis of enterocin-encoding genes showed the following genes: entP (n = 21), ent1071A/B (n = 11), entB (n = 8), entL50A/B (n = 7), entAS48 (n = 5), and entX (n = 1). Interestingly, 15 isolates harbored more than one ent gene. Antimicrobial susceptibility, phenotypic virulence, and genes encoding virulence factors were investigated by PCR. Resistance to tetracycline (n = 8: tetL + tetK), erythromycin (n = 7: 5 ermA, 2 msrA, and 1 mef(A/E)), ciprofloxacin (n = 1), gentamicin (n = 1: aac(6′)-aph(2″)), and linezolid (n = 1) were observed. Three isolates were gelatinase producers and eight were α-hemolytic. Three E. durans and one E. faecium harbored the hyl gene. Eight isolates showing safety properties (susceptible to clinically relevant antibiotics, free of genes encoding virulence factors) were tested to select probiotic candidates. They showed high tolerance to low pH and bile salt, hydrophobicity power, and co-culture ability. The eight isolates showed important phenotypic and genotypic traits enabling them to be promising probiotic candidates or food bio-conservers and starter cultures.

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 bla_TEM gene was found in 73.7% (14/19) of isolates from the three diseases, whilst the bla_CTXM-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.

Introduction: The spread of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-En) from turkeys via food chain and environmental contamination is a human health concern. Methodology: Seventy fecal samples were collected from healthy turkeys and streaked on Tryptone Bile X-Glucoronide (TBX) supplemented with 2 mg/L of cefotaxime and on TBX supplemented with 1 mg/L of imipenem. ESBL production and susceptibility to antibiotics were studied according to CLSI guidelines. Genes encoding for ESBLs (SHV, CTX-M, TEM), carbapenemases (IMI, KPC, OXA48, NDM), tetracyclines (tetA, tetB, tetC), colistin (mcr-1 to mcr-5), sulphonamides (sul1, sul2), quinolones (qnr A/B/S, aac(6’)-Ib-cr, qepA) resistance, and class 1 and 2 integrons were determined by PCR. Results: ESBL-En [n = 45 (64.3%): 41 E. coli and 4 K. pneumoniae] isolates were collected. In E. coli, blaCTX-M-1, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27, and blaCTX-M-55 genes were identified in 23, 2, 5, 16, and one isolate, respectively. The blaCTX-M-15 gene was detected in two K. pneumoniae isolates, while each of blaCTX-M-1 and blaCTX-M-27 were detected in one isolate. Resistances to tetracyclines, sulfonamides, fluoroquinolones, and colistin were encoded by tetA (n = 21)/tetB (n = 1), sul1 (n = 8)/sul2 (n = 13), aac(6’)-Ib-cr (n = 6), and mcr-1 (n = 2)/mcr-2 (n = 1) genes, respectively. Integrons of class 1 and class 2 were detected in 15 and six isolates, respectively. Five E. coli isolates belonged to the pandemic ST131 clone. Conclusions: Our findings highlight the high occurrence of MDR/ESBL-En and demonstrate the possible transfer of these strains to humans via the food chain or direct contact.