Prevalence and antibiotic resistance of foodborne Staphylococcus aureus isolates in Turkey.

Abstract In this study, 154 Staphylococcus aureus isolates were detected from 1070 food samples (14.4%) collected from seven cities in Turkey. Antimicrobial susceptibility testing against 21 antibiotics was performed by agar disk diffusion method, and those isolates resistant to any antibiotic were further analyzed to determine minimum inhibitory concentration by E-test and polymerase chain reaction analysis of vanA and mecA genes. According to disk diffusion test results, a total of 139 strains were resistant to at least one tested antibiotic, with 39 (25.3%) strains being multidrug resistant (MDR) and the other 15 strains being susceptible to all antibiotics. Penicillin G, linezolid, erythromycin, and tetracycline took up 71.4%, 23.4%, 18.2%, and 15.6% of the tested strains, respectively. In addition, all of the strains were susceptible to vancomycin, oxacillin, cefoxitin, and imipenem. Only one strain (S158B) was resistant to both teicoplanin and cefazolin. On the other hand, the presence of vanA and mecA genes was not detected in the strains. Pulsed-field gel electrophoresis analysis was used to identify genetic-relatedness of the MDR strains. It is noteworthy that some strains from different sources showed 100% homology; however, some of MDR strains were found unrelated with 60% or less homology. The high diversity observed in pulsed-field gel electrophoresis results indicated the possible contamination of S. aureus from different sources and routes.

The antimicrobial effects of chopped garlic in ground beef and raw meatball (cig köfte).

This study was carried out to investigate the antimicrobial effects of chopped garlic in ground beef and raw meatball (çig köfte), which is a traditional food product eaten raw. Fresh minced ground beef and raw meatball batter prepared with traditional methods were separated into groups. Chopped and crushed garlic was added to each batch in order to reach various concentrations from 0% to 10%. The ground beef samples were stored at refrigerator and ambient temperatures. The raw meatball samples were only stored at room temperature. All samples were analyzed in order to determine the microbial counts at the 2(nd), 6(th), 12(th), and 24(th) hours of storage. Garlic addition decreased the microbial growth in some ground beef samples kept either at room temperature or in the refrigerator. However, microbial growth increased in some ground beef samples kept in similar conditions. The difference was found in samples kept in the refrigerator for 24 hours in terms of total aerobic mesophilic bacteria and coliform bacteria when garlic used at 10%. The effects of garlic on the microbial growth of both coliforms and Staphylococcus/Micrococcus in the samples kept at room temperature were increased. The yeast and mold counts in ground beef samples kept in any condition were not affected by garlic addition. However, the addition of garlic to the raw meatball mix decreased the microbial count, in terms of total aerobic mesophilic bacteria and yeast and mold counts, when the garlic was added at 5% or 10% (P < .05). The addition of 10% garlic to raw meatball caused a permanent decrease in yeast and mold count, unlike in ground beef. The results of this study indicate that the chopped garlic has a slowing-down effect on microbiological growth in ground meat depending on the garlic concentration, but this effect was not at an expected level even at the highest concentration, because potential antimicrobial agents in chopped garlic were probably insufficiently extracted.

Identification and characterization of lactic acid bacteria isolated from traditional cone yoghurt.

Cone yoghurt is a yoghurt variety produced by adding only pine cones to milk without culture in a limited area of Turkey. The present study was conducted to identify and characterize lactic flora in traditional cone yoghurt. Morphological, cultural, physiological, biochemical, and genotypic characteristics were employed to identify lactic acid bacteria isolates from cones and cone yoghurts. Streptococcus salivarius subsp. thermophilus (S. thermophilus) and Lactobacillus delbrueckii subsp. bulgaricus (L. bulgaricus) were obtained from both cones and yoghurts. Among the isolates, L. plantarum was frequently isolated except for these two bacteria (S. thermophilus and L. bulgaricus). The results indicate that the cone yoghurt has a mixed microflora contrary to the yoghurt produced by the addition of a starter culture and S. thermophilus, and L. bulgaricus in cone yoghurt originates from the pine cones.

Investigations on the frequency of norovirus contamination of ready-to-eat food items in Istanbul, Turkey, by using real-time reverse transcription PCR.

Investigation of norovirus (NoV) contamination of food items is important because many outbreaks occur after consumption of contaminated shellfish, vegetables, fruits, and water. The frequency of NoV contamination in food items has not previously been investigated in Turkey. The aim of this study was to investigate the frequency of human NoV genogroups (G) I and II in ready-to-eat tomatoes, parsley, green onion, lettuce, mixed salads, and cracked wheat balls. RNA was extracted with the RNeasy Mini Kit, and a real-time reverse transcription (RT) PCR assay was performed using primers specific for NoV GI and GII. Among the 525 samples analyzed, NoV GII was detected in 1 green onion sample and 1 tomato sample by both SYBR Green and TaqMan real-time RT-PCR assays; no GI virus was detected. The Enterobactericaeae and Escherichia coli levels in the NoV-positive green onion were 6.56 and 1.28 log CFU/g, and those in the tomato were 5.55 and 1.30 log CFU/g, respectively. No significant difference in the bacterial levels was found between the NoV-positive and NoV-negative samples. This study is the first in which NoV GII was found in ready-to-eat food collected from Istanbul, Turkey; thus, these foods may be considered a risk to human health. Epidemiological studies and measures to prevent NoV infection should be considered.

Frequency and phylogeny of norovirus in diarrheic children in Istanbul, Turkey.

BACKGROUND: Norovirus (NoV) is recognised as one of the most common causes of foodborne infections. Contaminated shellfish, food, water and hospitals are well documented sources of the virus. OBJECTIVE: NoV in diarrheic children has not previously been investigated in Istanbul, Turkey, hence the aim of this study was to detect and investigate the frequency and phylogeny of human NoV genogroups I and II in children with acute gastroenteritis. STUDY DESIGN: 238 stool samples were collected from diarrheic children from 2 hospitals (Cerrahpasa Medical School and Haseki) in Istanbul and analysed by ELISA, RT-PCR and real-time RT-PCR using both SYBR Green and probe-based assays for human NoV. Primers targeting the RNA-polymerase gene were used for RT-PCR to allow DNA sequencing of Turkish NoV strains and phylogenetic analysis to be performed. RESULTS: NoV GII was detected in 36 (15.1%) of 238 samples by SYBR Green real-time RT-PCR, 10.9% by a probe-based real-time RT-PCR and 10.5% by ELISA (Ridascreen). Genogroup II (GII) the Turkish NoVs clustered with including GII4 (72.2%), GII16 (5.5%), GIIb (16.7%) and GIIe (5.5%). Two variants of GII4 (GII4-2006b and GII4-2008), GII16 and recombinant noroviruses (GIIb and GIIe) were identified. CONCLUSION: This study shows a high frequency and genetic diversity of NoV GII infections in children with acute gastroenteritis in Istanbul, Turkey.

[A view of mites infestation on cheese and stored foods in terms of public health]. / Depo gidalarini ve peynirleri enfeste eden akarlara halk sagligi açisindan bakis

Mites are small live organism that may result in a large number of allergenic diseases such as atopic dermatitis, allergic rhinitis and asthma that may cause individuals' physical, social and mental health, adversely affects quality of life. Mites that can be found everywhere where people live are found in various foodstuffs. The purpose of this review is to examine the types of mites and possible illness result from mites can be found in stored foods especially cheese in terms of public health assessment. Finding mite in the stored foods except for some local cheeses is not desirable because of it's health risks. However, especially in cheese which is maturing in the open always to be the case of mite enfestation. In particular, this risk is much higher in some enterprises where have not taken measures enough in terms of food safety. Besides the lack of standarts related to cheese, fighting against mite in quality assurance systems have generally not been taken into consideration. Whereas mites in cheese consumed by individuals at any age, there is always a possibility of the potential cause of the allergic reactions seen in the consumer. Prevention of possible infestations in cheese, potential presence of storage mite and cheese mite in various stored foods and local cheese of Turkey should be investigated more comprehensive and protective measures should be developed in order to protect public health against mites.

Prevalence and antibiotic susceptibility of thermophilic Campylobacter species on beef, mutton, and chicken carcasses in Istanbul, Turkey.

We investigated the prevalence of contamination of retail-level beef, mutton, and broiler carcasses in Istanbul, Turkey, by thermophilic Campylobacter spp. (TCS) and determined antimicrobial susceptibilities of the TCS strains isolated from these carcasses. From November 2005 to October 2006, 198 beef and 120 mutton carcass excision samples, and 232 chicken carcasses (whole and pieces) were randomly collected from different retail stores and meat-processing plants in Istanbul. TCS were isolated from 11.1%, 21.6%, and 50.4% of beef, mutton, and chicken samples tested, respectively. There was no significant seasonal variation in the prevalence of TCS. A total of 292 Campylobacter isolates were obtained from the samples (56.5% C. jejuni, 33.9% C. Coli, and 9.6% C. lari). C. jejuni was the species most commonly isolated from chicken meat (56.5%<65.9 from table 2>), while C. coli was the most common in beef (63.3%) and mutton (63.9%) carcasses. Susceptibilities of 246 strains for eight antimicrobial drugs were determined using disk diffusion assay. Campylobacter isolates were most often resistant to tetracycline (69.1%), followed by trimethoprim-sulfamethoxazole (64.2%), nalidixic acid (58.1%), erythromycin (56.9%), enrofloxacin (48.8%), ciprofloxacin (42.7%), chloramphenicol (36.2%), and gentamicin (26.0%). The results of this study suggest that a high proportion of meat samples, particularly chicken carcasses, are contaminated by TCS, most of which are antimicrobial-resistant strains. Since campylobacteriosis is transmitted primarily through food of animal origin, the presence of antimicrobial-resistant strains in meat has important implications for public health and food safety.