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    Genetic diversity and antibiotic resistance profiles of Campylobacter jejuni isolates from poultry and humans in Turkey
    (Elsevier, 2014) Abay, Secil; Kayman, Tuba; Otlu, Baris; Hizlisoy, Harun; Aydin, Fuat; Ertas, Nurhan
    In this study, the investigation of clonal relations between human and poultry Campylobacter jejuni isolates and the determination of susceptibilities of isolates to various antibiotics were aimed. A total of 200 C. jejuni isolates concurrently obtained from 100 chicken carcasses and 100 humans were genotyped by the Pulsed-Field Gel Electrophoresis (PFGE) and automated Repetitive Extragenic Palindromic PCR (Rep-PCR, DiversiLab system) methods and were tested for their susceptibility to six antibiotics with disk diffusion method. The minimum inhibitory concentration (MIC) values of ciprofloxacin (CI), enrofloxacin (EF) and erythromycin (EM) were evaluated by E-test. By using PFGE 174 of (87.0%) the isolates were able to be typed. The clonally related strains were placed in 35 different clusters and 115 different genotypes were obtained. All of the two hundred isolates could be typed by using Rep-PCR and were divided into 133 different genotypes. One hundred and fourteen clonally related isolates (57.0%) were included in 47 clusters. In disk diffusion test, while the susceptibility rates of AMC and S to human and chicken derived C jejuni isolates were 84.0%-96.0% and 96.0%-98.0%, respectively, all isolates were susceptible to gentamicin. The resistance rates of human isolates to AMP, NA and TE were detected as 44.0%, 84.0% and 38.0% of the resistances of chicken isolates to these antibiotics were 34.0%, 95.0% and 56.0%, respectively. The MIC values of human and chicken isolates to Cl, EF and EM were detected as 81.0-93.0%, 85.0-88.0% and 6.0-7.0%, respectively. The clonal proximity rates were detected between human and poultry origin C. jejuni isolates. The discriminatory power of PFGE and Rep-PCR was similar, with Simpson's diversity indexes of 0.993 and 0.995, respectively. Concordance of the two methods as determined by Adjusted Rand coefficient was 0.198 which showed the low congruence between Rep-PCR and PFGE. High rates of quinolone resistance were detected in C. jejuni isolates. This study demonstrated that chicken meat played an important role for infections caused by C. jejuni in Turkey and erythromycin, amoxicillin clavulanic acid and gentamicin are recommended for the treatment of Campylobacteriosis in humans. (c) 2014 Elsevier B.V. All rights reserved.
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    Lactiplantibacillus Plantarum Postbiotics Suppress Salmonella Typhimurium Invasion and Modulate Innate Responses in Human Intestinal Epithelial Cells
    (Springer, 2025) Cobur, Hazal; Loker, Neriman; Dishan, Adalet; Vurmaz, Melike; Karatepe, Pinar; Hizlisoy, Harun; Akcay, Aytac
    Postbiotics derived from Lactiplantibacillus plantarum (LPP) exhibit promising potential as safe modulators of intestinal health. Here, the chemical, antimicrobial, and host-regulatory properties of LPP against Salmonella enterica serovar Typhimurium were investigated using a human intestinal epithelial (Caco-2) cell model. The LPP exhibited broad-spectrum antimicrobial activity against major foodborne pathogens, with minimal inhibitory concentrations ranging between 12.5 and 25 mg/mL. Treatment of Caco-2 cells with sub-MIC doses of LPP (6.25 mg/mL) significantly suppressed intracellular invasion of Salmonella (P < 0.05). Gene expression analysis revealed consistent downregulation of NF-kappa B gene expression following LPP presence with sublethal doses (P < 0.001), while no significant changes were detected in the expression levels of other key proinflammatory cytokines during the early phases (six and 12 h) of infection. A significant increase (P < 0.001) in apoptotic cell rates occurred at six h post-infection (PI), while no significant differences were observed at 12 h PI. The results revealed that LPP not only suppresses Salmonella invasion but also shows time-dependent modulation of inflammatory signaling and apoptotic responses in intestinal epithelial cells. These observed effects can be attributed to the bioactive compounds present in LPP, including organic acids, free amino acids, free fatty acids, polyphenols, and volatiles. The findings suggest that L. plantarum postbiotics can attenuate bacterial invasion and modulate innate immune response mechanisms without compromising host cell viability.