Detekcija enterotoksigene bakterije Staphylococcus aureus u sirovom i pasteriziranom mlijeku

The aim of this study was to investigate staphylococcal enterotoxins (SEs) by ELISA, and detect the five classical sea, seb, sec, sed, and see genes by real-time PCR in Staphylococcus aureus isolates from raw and pasteurized milk samples. Staphylococcus spp. were isolated from 98 out of 100 raw milk samples, and in 6 out of 100 pasteurized milk samples. On further biochemical tests, S. aureus was isolated in 48 samples (48%) of raw milk (n=100) and in one sample (1%) of pasteurized milk (n=100). Ten (10%) out of 100 raw milk samples were positive for at least one enterotoxin, and the most frequently observed SE was SEA (10%), followed by SEE (7%) and SEB (6%), but none of the isolates were positive for SEC and SED. At least one of the SEs gene types (sea, seb, sec, sed, see) was detected in 45 (93.8%; 45/48) S. aureus isolates from raw milk samples. sec, sea, seb, sed, and see genes were observed in 56.2%, 39.5%, 31.2%, 29.1% and 14.5% of strains respectively. The enterotoxin genes were the single type in 21 (46.7%) of the 45 isolates, there were two in 15 (33.3%), three in six (13.3%), four in two (4.4%), and one (2.2%) in all gene regions. The SE gene was not detected in the S. aureus (n=1) isolate from pasteurized milk. As a result of this study, the presence of enterotoxigenic S. aureus in raw milk was revealed, and it was pointed out that these SEs may contribute to cases of staphylococcal foodborne poisoning (SPF).Cilj je bio u izolatima bakterije Staphilococcus aureus iz sirovog i pasteriziranog mlijeka pomoću ELISA testa istražiti enterotoksine stafilokoka (SEs) te uporabom PCR-a u stvarnom vremenu provjeriti prisustvo pet gena, sea, seb, sec, sedi i see. Bakterija Staphylococcus spp. izolirana je iz 98 od 100 uzoraka sirovog mlijeka i iz 6 od 100 uzoraka pasteriziranog mlijeka. Daljnjim je biokemijskim testiranjem S. aureus izolirana iz 48 uzoraka (48%) sirovog mlijeka (n=100) i iz jednog uzorka (1%) pasteriziranog mlijeka (n=100). Ukupno je 10 uzoraka (10%) od 100 uzoraka sirovog mlijeka bilo pozitivno na barem jedan enterotoksin, a najčešći je enterotoksin bio SEA (10%), zatim SEE (7%) i SEB (6%). Ni jedan od izolata nije bio pozitivan na SEC i SED. Najmanje je jedan tip gena za enterotoksine (sea, seb, sec, sed, see) otkriven u 45 izolata (93,8%, 45/48) S. aureus iz uzoraka sirovog mlijeka. Gen sec uočen je u 56, 2% sojeva, gen sea u 39,5% sojeva, gen seb u 31,2% sojeva, gen sed u 29,1% sojeva i gen see u 14,5% sojeva. Geni za enterotoksine pronađeni su kao pojedinačan tip u 21 od 45 izolata (46,7%), dva od 15 izolata (33,3%), tri od šest izolata (13,3%), četiri od dva izolata (4,4%) i jedan (2,2%) u svim regijama gena. Gen za enterotoksin nije pronađen u izolatu S. aureus (n=1) iz pasteriziranog mlijeka. Ovo je istraživanje pokazalo da se enterotoksigena bakterija S. aureus nalazi u sirovom mlijeku, pri čemu je naglašeno da enterotoksini mogu pridonijeti trovanju hranom uzrokovanom stafilokokima (SPF)

Prevalence, Antimicrobial Resistance and Molecular Characterization of Salmonella spp. and Listeria monocytogenes Isolated from Chicken Carcass

This study aimed to investigate the prevalence of Salmonella spp. and Listeria monocytogenes, their antimicrobial resistance profile. L monocytogenes was not isolated from any of the samples. Salmonella spp. was detected from 32 (8%) out of the 400 collected samples. Antimicrobial resistance was most frequently observed to nalidixic acid (100%), tetracycline (93.75%), erythromycin (90.6%), streptomycin (84.3%), followed by kanamycin (62.5%). Also, 37.5% of Salmonella isolates were phenotypically confirmed as ESBL producers. Multiple drug resistance was defined 93.75% of the Isolates. Among the Salmonella isolates, all of them harbouring qnrB and qnrS genes and, 37.5% of them presented bla(TEM) gene.

Tavuk Karkaslarından İzole Edilen Salmonella spp. ve Listeria monocytogenes Prevalansı, Antimikrobiyal Direnci ve Moleküler Karakterizasyonu

This study aimed to investigate the prevalence of Salmonella spp. and Listeria monocytogenes, their antimicrobial resistance profile. L monocytogenes was not isolated from any of the samples. Salmonella spp. was detected from 32 (8%) out of the 400 collected samples. Antimicrobial resistance was most frequently observed to nalidixic acid (100%), tetracycline (93.75%), erythromycin (90.6%), streptomycin (84.3%), followed by kanamycin (62.5%). Also, 37.5% of Salmonella isolates were phenotypically confirmed as ESBL producers. Multiple drug resistance was defined 93.75% of the Isolates. Among the Salmonella isolates, all of them harbouring qnrB and qnrS genes and, 37.5% of them presented bla(TEM) gene.

Incidence of Aeromonas hydrophila and Plesiomonas shigelloides in Seafoods

The present study was conducted to investigate the incidence of the pathogens Aeromonas hydrophila and Plesiomonas shigelloides in 700 seafoods (400 raw fish, 100 raw shrimps and 200 raw mollusks) collected from retailers. Isolations were performed by conventional culture methods. The isolates were also confirmed by polymerase chain reaction (PCR) assays. A. hydrophila and P. shigelloides were detected in 5.71% and 0.86% seafood samples, respectively. The highest rate of A. hydrophila (15%) was found in shrimp samples. P. shigelloides were only isolated from fish samples. The study is showed that effective methods to eliminate the Aeromonas and Plesiomonas species are needed

Effect of rosemary essential oil and modified-atmosphere packaging (MAP) on meat quality and survival of pathogens in poultry fillets

The effect of rosemary (Rosmarinus officinalis L.) essential oil (REO) and modified-atmosphere packaging (MAP) on the survival of certain pathogens (Salmonella Typhimurium and Listeria monocytogenes) in poultry fillets and on their meat quality during 7 days of refrigerated storage were investigated. Because REO at 0.05% and 0.1% had weak antibacterial activity and REO at 0.3%, 0.5% and 1.0% imparted unacceptable organoleptic properties, only REO at 0.2% was used to treat the poultry meat. The results showed that adding 0.2% REO to poultry fillets did not reduce the size of the population of S. Typhimurium and L. monocytogenes. However, REO treatment significantly decreased the L* (lightness) value and increased the a* (redness) value of stored fillets, and adding REO in combination with MAP reduced the level of lipid oxidation. In conclusion, in a suitable combination, REO can be applied to improve the quality of meat, but further studies should be conducted to determine the appropriate commercial level for different meat products

Antimicrobial Susceptibility Profiles and Coagulase Gene Polymorphism of Staphylococcus aureus Isolated from Bovine Subclinical Mastitis

The purpose of the study was to isolate Staphylococcus aureus from bovine subclinical mastitis, determine their antibiotic susceptibilities and investigate the coagulase gene polymorphism by using a PCR-based restriction fragment length polymorphism (RFLP) method. Milk samples from 463 CMT positive udders from 237 cows cultured. The antimicrobial susceptibility of the isolates were determined by disc diffusion method. A total of 82 out of the 83 isolates (98.8%) were found to be resistant at least one out of the 16 antibiotics studied. In this experiment 53 isolates (63.8%) were found to be resistant to penicillin; 52 (62.67%) to trimethoprim/sulphamethoxazole; 51 (61.5%) to ampicillin; 40 (48.2%) to erytromycin; 29 (34.9%) to tetracycline; 18 (21.6%) to ciprofloxacin, 16 (19.3%) to clindamycin, 13 (15.6%) to chloramphenicol; 8 (9.6%) to gentamicin; 5 (6.0%) to cefoxitin; 4 (4.9%) to vancomycin; 3 (3.6%) to cephalotin; 2 (2.4%) nafcillin; one (1.2%) to oxacillin and one to (1.2%) furazolidon. No imipenem resistance was seen in the S. aureus isolates. The coagulase gen polymorphism were examined by PCR amplification of coagulase gene followed by AluI digestion of repeating 81 bp DNA sequences. After nested PCR, double bands were produced in 8 of the isolates while there were single band in remaining 75 isolates. Following AluI digestion, isolates that formed single band in length of approximately 300 bp showed 3 different groups

TETRACYCLINE RESISTANCE OF ENTEROBACTERIACEAE ISOLATED FROM FECES OF SYNANTHROPIC BIRDS

Tetracycline is a broad-spectrum antibiotic which is commonly used in humans and animals for treatment of bacterial infections. Therefore, tetracycline-resistant Enterobacteriaceae species found in the nature, humans, and animals are usually considered a serious health concern. The feces of birds that live with humans may be a source for of these antibiotic resistant bacteria. For this reason, presence of tetracycline resistant Enterobacteriaceae in bird droppings collected from 18 different breeders and pet shops fed in Istanbul was investigated by cultural and molecular methods in terms of the presence of that a/b gene. In addition, susceptibilities of isolates to various antibiotics were also determined. The current study reported that Enterobacter cloacae, Citrobacter freundi, Escherichia coli, Edwardsiella spp., Enterobacter spp., Escherichia vulneris, Klebsiella pneumonia, Pantoea agglomerans, Proteus mirabilis, Pantoe spp., Pseudomonas spp., Serratia marcescens, Salmonella spp., Shigella spp. were isolated from the samples. Ninety-seven of the isolates (97/150) were resistant to tetracycline (65.2%). In addition, the isolates were resistant to other antibiotic medications and 114 of them (58%) evaluated as multi drug resistant. The tet (A) and tet (B) genes were found in bacteria isolated from synantrophic birds' feces as 46.6% and 8%, respectively. Although working conditions are limited, the results obtained provide baseline information regarding antibiotic resistance to Enterocatericeae isolates obtained from captive birds' feces. Thus, the results of the present study emphasize the necessity of genotypic resistance research in future studies to help maintain antibiotic treatment efficacy for Enterocatericeae infections. Copyright 2018 Elsevier Inc. All rights reserved