Detection of vancomycin-resistant enterococci in samples from broiler flocks and houses in Turkey.

Vancomycin-resistant enterococcus (VRE) is a global threat to public health. Knowledge about the occurrence of vanA-carrying enterococci in broiler and environmental samples is important as antibiotic resistance can be transferred to human bacteria. The aim of this study was to investigate the presence of VRE in broiler cloacal and environmental (house) samples and to genotype the isolates. In this study, 350 swabs were collected from broiler farms. All samples were plated onto enterococcus selective agar containing 6 mg/L vancomycin and 64 mg/L ceftazidime. Minimum inhibitory concentration (MIC) values were determined for vancomycin and teicoplanin. Vancomycin-resistant Enterococcus faecium (VREfm) was isolated from 6 out of 300 (2%) broiler cloacal samples and 13 out of 50 (26%) house samples. All E. faecium isolates had vanA genes. All VREfm isolates (19 isolates) were confirmed to be 95% similar to each other. In conclusion, although 20 years have passed since the ban on avoparcin in Turkey, the present study shows that VREfm isolates are still present in broiler production and especially in broiler houses, and most importantly, a major VREfm clone was isolated from broiler cloacal and house samples.

[Investigation and Genotyping of Chlamydia psittaci ompA Gene in Pigeon (Columbia domestica) Feces]. / Güvercin (Columbia domestica) Diskilarinda Chlamydia psittaci ompA Geninin Arastirilmasi ve Genotiplendirilmesi.

Avian chlamydiosis, is a highly contagious, systemic disease occuring in domestic and wild birds. Chlamydia psittaci, the causative agent of the disease, is a gram-negative bacterium in the Chlamydiaceae family that can only live within the cell. The agent can be transmitted directly to humans by contact with infected animals or feces of infected animals. It can also be transmitted by inhalation of fecal dust. Since the disease has a zoonotic character, it is also important in terms of public health. By using the monoclonal antibodies against cell wall proteins (OMP) of C.psittaci, six (A-F) and two (WC and M56) serotypes were determined in mammals. The aim of this study was to investigate and genotype the presence of C.psittaci ompA gene in domestic pigeon feces grown in family management style in ten different districts in Ankara in winter and summer seasons. Within the scope of the study, 100 pigeon stool samples were collected from birdhouses in 10 different districts of Ankara (Beypazari, Haymana, Kizilcahamam, Cubuk, Pursaklar, Bala, Cankaya, Polatli, Golbasi and city center) in two different seasons. DNA extraction from fecal samples was performed by classical methods. The presence of the agent in the extracted DNA samples was investigated by polymerase chain reaction (PCR) analysis of the ompA gene. Two-way sequence analysis of the ompA gene was performed with the primers used in the study from the target DNA products amplified by PCR. The results of sequence analysis were compared with the international database and serotyping/genotyping was performed. In the study, C.psittaci ompA gene was detected in 6 (6%) samples of 100 pigeon stool samples. Among these positive samples, two were from Bala (one sample from winter, one sample from summer), two were from Haymana (one sample from winter, one sample from summer) and two were from Golbasi (one sample from winter, one sample from summer); where the same agent was isolated in the same aviaries in different seasons. In this study, no difference was found between the presence of C.psittaci in pigeon droppings and season. In addition when the sequence analysis of the isolated samples were compared with the World database; all isolates were found to be 100% genotype B and 99% genotype E. In this study, the sequence analysis of the ompA gene of C.psittaci from domestic pigeon feces was determined for the first time in Turkey. Although the presence of C.psittaci in domestic pigeons is low, it is a zoonotic bacterium and is important for the public health.

Development and characterization of polymeric-based nanoparticles for sustained release of amoxicillin - an antimicrobial drug.

In this study, amoxicillin (AMO)-loaded poly(vinyl alcohol)/sodium alginate (PVA/NaAlg) nanoparticles were prepared as a polymer-based controlled release system. The physicochemical properties of the obtained nanoparticles were investigated by XRD, DSC/TGA, particle size analyses and zeta potential measurements. The average particle sizes were in the range from 336.3 ± 25.66 to 558.3 ± 31.39 nm with negative zeta potential values from -41.86 ± 0.55 to -47.3 ± 2.76 mV. The influences of PVA/NaAlg ratio, span 80 concentration, exposure time to glutaraldehyde (GA) and the drug/polymer ratio on AMO release profiles were evaluated. In vitro drug release studies showed a controlled and pH dependent AMO release with an initial burst effect. XRD patterns and DSC thermograms of AMO-loaded nanoparticles revealed that the drug in the nanoparticles was in amorphous form, which was more stable than the crystalline form. The antibacterial activity of the optimal formulation was also investigated. The minimum inhibitory concentration (MIC) values of this formulation had the comparable antibacterial activity with that of pure AMO. These results indicate that the developed nanoparticles could be a promising candidate drug delivery system for AMO.

Panton-Valentine leukocidin and some exotoxins of Staphylococcus aureus and antimicrobial susceptibility profiles of staphylococci isolated from milks of small ruminants.

The aims of this study were to determine the existence of pvl gene, some toxin genes, and mecA gene in Staphylococcus aureus strains isolated from sheep milk and to examine antimicrobial resistance profiles in staphylococci from sheep and goats' milk. The milk samples were collected from 13 different small ruminant farms in Kirikkale province from February to August 2009. A total of 1,604 half-udder milk samples from 857 ewes and 66 half-udder milk samples from 33 goats were collected. Staphylococcus spp. were isolated and identified from the samples. Toxin genes and mecA gene among S. aureus strains were determined by PCR. Antimicrobial susceptibility of staphylococci was examined by the disk diffusion method on Mueller-Hinton agar, and interpreted according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The prevalence of subclinical intramammary infection in both ewes and goats was 5.2%. The most prevalent subclinical mastitis agents were coagulase-negative staphylococci and S. aureus with prevalences 2.8% (n:46) and 1.3% (n = 21), respectively. The prevalence of resistances in isolated Staphylococcus spp. to penicilin G, tetracycline, erythromycin, gentamicin, and enrofloxacin were found as 26.9% (18), 7.5% (5), 6.0% (4), 3.0% (2), and 1.5% (1), respectively. Only 3 of the 21 S. aureus ewe isolates (13.4%) were shown to harbor enterotoxin genes being either seh, sej or sec. However, fourteen (66.6%) of the 21 S. aureus isolates had pvl gene while none of the isolates harbored mecA gene. In conclusion, Staphylococci were shown to be the most prevalent bacteria isolated from subclinical mastitis of ewes and goats and these isolates were susceptible to most of the antibiotics. In addition, S. aureus strains isolated from ewes were harboring few staphylococcal enterotoxin genes. However, Panton-Valentine leukocidin produced by S. aureus could be an important virulence factor and contribute to subclinical mastitis pathogenicity.

Detection of stapylococcal enterotoxin, methicillin-resistant and Panton-Valentine leukocidin genes in coagulase-negative staphylococci isolated from cows and ewes with subclinical mastitis.

Coagulase-negative staphylococci (CNS) are the most prevalent mastitis pathogens. However, virulence characteristics of CNS have not been well determined. The presence of genes for enterotoxins (sea-sej), toxic shock syndrome toxin-1 (tst), the exfoliative toxins (eta, etb), Panton-Valentine leukocidin (pvl) and mecA of CNS species isolated from cows and ewes with subclinical mastitis was investigated in this study. A total of 121 CNS (81 cows, 40 ewes) representing 18 different Staphylococci species were examined by PCR, and 38.1% (33 cows and 13 ewes) of CNS isolates had one or more se genes. The difference between percentages for SE toxin genes of CNS strains isolated from cows (40.7%) and ewes (32.5%) was not statistically significant (P > 0.05; χ(2) = 0.380). It was found that S. simulans isolates had the highest prevalent se genes. Furthermore, the most common SE gene types was seh-sej. In this study, none of the isolates harbored the toxic shock syndrome toxin gene (tsst) and the exfoliative toxin genes (eta, etb). Five cow (6.17%) and three ewe CNS (7.5%) isolates had mecA gene. Three cow (3.7%) and two ewe CNS (5.0%) isolates had pvl gene. In conclusion, the present study showed that CNS species isolated from cows and ewes could serve as potential reservoir of se, mecA, and pvl genes.

[Resistance to newer beta-lactams and related ESBL types in gram-negative nosocomial isolates in Turkish hospitals: results of the multicentre HITIT study]. / Türkiye'de hastane izolati gram-negatif bakterilerde yeni beta-laktam antibiyotiklere direnç ve GSBL tipleri: çok merkezli HITIT sürveyansinin sonuçlari.

Increasing resistance due to extended-spectrum beta-lactamases (ESBLs) and multiple resistance mechanisms in gram-negative hospital isolates restrict the role of beta-lactam antibiotics in empirical treatment of serious infections. As the prevalence of ESBL producing strains and resistance rates to antimicrobial agents can vary in each center, local surveillance studies are required to guide therapy. In this study, in vitro rates of resistance to ceftriaxone, ceftazidime, cefepime, imipenem, cefoperazone/sulbactam and piperacillin/tazobactam were evaluated in 1196 gram-negative hospital isolates in a multicenter in vitro study with the participation of six different centers in Turkey between the period of June 2004-January 2005. The isolates included Escherichia coli (n= 457), Klebsiella pneumoniae (n= 390), Pseudomonas aeruginosa (n= 194) and Acinetobacter boumannii (n= 155). In addition, frequency of ESBL production and types of enzymes were determined in blood isolates of E. coli and K. pneumoniae. MICs and ESBL production were investigated by E-test (AB Biodisk, Solna) and the results were evaluated by using CLSI breakpoints. PCR analysis was used for typing of the ESBLs. In E. coli, 26% and in K. pneumoniae 32% of the isolates were ESBL producers. Among the blood isolates of E. coli and K. pneumoniae, 31.7% and 33.3% produced ESBLs, respectively. CTX-M (71.4%) was the most prevalent enzyme, followed by TEM (49.4%) and SHV (46.7%) derived enzymes. CTX-M-15 (69.4%) was the most frequent CTX-M type in blood isolates followed by CTX-M-3 (28.6%) and CTX-M-1 (2%). Resistance to imipenem was not observed in E. coli isolates, however it was 1.3% in K. pneumoniae, 28.9% in P. aeruginosa and 52.2% in A. baumannii strains. Resistance to cefoperazone/sulbactam was found as 6%, 17.7%, 27.9% and 41.3% in E. coli, K. pneumoniae, P. aeruginosa and A. baumannii isolates, respectively, whereas resistance rates to piperacillin/tazobactam were 10.2%, 22.3%, 22.7% and 78.7%, respectively. These results indicate that ESBL production and rates of resistance to beta-lactam antibiotics are high in hospital isolates of gram-negative bacteria in Turkey, however, they show variations in different hospitals and CTX-M enzymes are prevalent in these isolates.