[Determination of the role of Salmonella enterica plasmids in antibiotic susceptibility and Caenorhabditis elegans pathogenicity]. / Salmonella enterica plazmitlerinin antibiyotik duyarliligi ve Caenorhabditis elegans patojenitesindeki rollerinin belirlenmesi.

Poultry animals and poultry associated products are important risk sources for Salmonellosis. S.Kentucky and S.Infantis are among the serovars frequently isolated from retail chickens and were reported to be isolated in Turkey. In this study, the role of plasmids carried by S.Kentucky and S.Infantis isolates in antibiotic resistance profiles of the isolates and their pathogenicity on Caenorhabditis elegans nematode model system were investigated. The isolates used, 1 of Kentucky and 2 of Infantis serotypes, were selected among food-borne Salmonella isolated from chicken carcass in Edirne. All three isolates were previously shown to contain plasmids carrying multidrug resistance and were known to be pathogenic on C.elegans nematode model system. S.Kentucky A10 isolate was resistant to ampicillin, nalidixic acid, tetracycline, ciprofloxacin, trimethoprim and sulphonamide and carried one plasmid with 31.6 kb size. S.Infantis A15 isolate was resistant to ampicillin, streptomycine, nalidixic acid, tetracycline, neomycin, sulphonamide and kanamycin and carried a plasmid with 19.9 kb size while the other S.Infantis isolate (A16) was resistant to streptomycin, nalidixic acid, tetracycline, trimethoprim, neomycin, sulphonamide and kanamycin and carried 3 plasmids with 42.4, 1.5 and 1.2 kb sizes. Plasmid curing experiments were performed to investigate the role of plasmids in antibiotic resistance and pathogenicity in C.elegans. Ethidium bromide (EtBr) dye was used as the plasmid curing agent. Plasmids were isolated from cultures grown in LB broth with different concentrations of EtBr (50, 75, 100, 125 µg/ml) according to the Kado-Liu method and the most effective EtBr concentration was determined as 125 µg/ml. C.elegans pathogenicity assays were carried out using plasmid cured isolates. The time 50% of the nematode die (TD50) values of the nematode groups fed with plasmid cured isolates were compared with previously obtained TD50 values of the nematode groups fed with wild type Salmonella isolates. Studentðs t-test (p< 0.05) was used to showthe level of significance between TD50 values of the two groups. TD50 values of the positive control group fed with S.Typhimurium ATCC 14028 and the negative control group fed with Escherichia coli OP50 were found as 4.0 ± 0.4 and 8.0 ± 0.02 days, respectively. The differences between TD50 values of nematode groups fed with wild type and plasmid cured isolates were statistically significant both for S.Kentucky (A10) (4.9 ± 0.04-6.2 ± 0.1) and S.Infantis (A16) (4.4 ± 0.01-6.2 ± 0.2) (p< 0.05) strains, but no significant difference was observed for the groups fed with wild type and plasmid cured S.Infantis (A15) (5.7 ± 0.39-5.8 ± 0.16) strain. Broth microdilution method was used to determine whether there was any change in minimal inhibitory concentrations (MIC) of the antibiotics for which the isolates were resistant before plasmid elimination. No significant difference was found between the MIC values of the resistant antibiotics among Salmonella isolates carrying plasmids and with cured plasmid. This study is important since the first in vivo results about the role of Kentucky and Infantis serovar plasmids on C.elegans nematode model system were presented.

[Investigation of pathogenic phenotypes and virulence determinants of food-borne Salmonella enterica strains in Caenorhabditis elegans animal model]. / Gida kökenli Salmonella enterica suslarinin patojenik fenotiplerinin ve virülans determinantlarinin Caenorhabditis elegans hayvan modelinde incelenmesi.

Salmonellosis, caused by non-typhoidal Salmonella enterica serovars with the consumption of contaminated food, is one of the leading food-borne disease that makes microbial food safety an important public health issue. This study was performed in order to determine the antibiotic resistance, serotyping, plasmid profiles and pathogenicity potentials of food-borne Salmonella isolates in Caenorhabditis elegans animal model system in Edirne province, located at Thrace region of Turkey. In this study, 32 Salmonella isolates, of which 26 belonged to Infantis, four to Enteritidis, one to Telaviv and one to Kentucky serovars, isolated from chicken carcasses were used. Antibiotic resistance profiles were determined by disc diffusion and broth microdilution methods. A new C.elegans nematode animal model system was used to determine the pathogenicity potential of the isolates. The antibiotic resistance profiles revealed that one (3.1%) isolate was resistant to gentamicin, two (6.2%) to ciprofloxacin, three (9.4%) to ampicillin, 18 (56.3%) to kanamycin, 19 (60.8%) to neomycin, 25 (78.1%) to tetracycline, 25 (78.1%) to trimethoprim, 26 (81.25%) to nalidixic acid, 27 (84.4%) to streptomycin and 32 (100%) to sulfonamide. All of the 32 strains were susceptible to chloramphenicol and ampicillin/sulbactam. High levels of resistance to streptomycin, nalidixic acid, tetracycline, trimethoprim, sulfonamide, kanamycin and neomycin was determined. According to the plasmid analysis, six isolates (18.75%) harboured 1-3 plasmids with sizes between 1.2 and 42.4 kb. In C.elegans nematode animal model system, the time (in days) required to kill 50% (TD50) of nematodes was calculated for each experimental group. TD50 values of the nematode group fed with S.Typhimurium ATCC 14028 that was used as the positive control and another group fed with E.coli OP50 as the negative control were 4.2 ± 0.5 days and 8.0 ± 0.02 days, respectively. TD50 of the groups fed with Salmonella isolates ranged between 3.4 and 7.3 days. The significance of the differences between TD50 values of the positive control and experimental groups was analysed by using Student's t test. Ten of the isolates (31.25%), of which six belonged to Infantis and four to the Enteritidis serotypes were non-pathogenic, and the rest 22 isolates including Infantis, Kentucky and Telaviv serovars (67.75%) were found to be pathogenic for the C.elegans animal system (p< 0.05). Twenty of the isolates (90.9%) which were determined as pathogens showed multiple drug resistance and three of them possessed 1-3 plasmids, sizes between 1.2 - 42.4 kb. The overall results underlined wide distribution of antibiotic-resistant Salmonella enterica strains and provided a practical alternative for studies aiming determination of pathogenic potential of environmental and food-borne strains through new experimental animal infection model. In this study, C.elegans was utilized for the first time to determine the profiles of pathogenicity of food-borne Salmonella serotypes in Turkey.

Radio-guided nonpalpable metastatic lymph node localization in patients with recurrent thyroid cancer.

The detection of nonpalpable recurrent thyroid carcinoma has increased due to the use of imaging techniques in time. This report is to investigate whether preoperative injection of a radiotracer under ultrasound guidance is useful in nonpalpable recurrent thyroid carcinoma. The neck of two patients with recurrent thyroid carcinoma was scanned with the probe to localize the area of maximal radioactivity allowing appropriate location of the incision over the lesion. After the lymph nodes were removed, radioactivity was measured in the lesion bed to confirm the success of the dissection. In conclusion, the radio-guided nonpalpable lesion localization technique can be performed safely for the detection and excision of metastatic foci.