[Comparison of genotypic and phenotypic characteristics in biofilm production of Staphylococcus aureus isolates]. / Staphylococcus aureus izolatlarinda biyofilm üretiminin genotipik ve fenotipik karakterlerinin karsilastirilmasi.

Staphylococcus aureus which is an important pathogen, is known to have several virulence factors. The pathogenicity of S.aureus isolates are related with features like adherence, various toxins, enzymes, structural and extracellular factors. Slime factor and biofilm formation are also the pathogenicity factors of the bacteria. Biofilm formation is usually associated with chronic infections and has become a subject of interest in a wide area of research. Biofilm is an adherent structure formed by bacteria encased within a matrix produced on natural body surfaces or medical devices. As the biofilm producing S.aureus isolates are more resistant to antibiotics and and their biofilms prevent phagocytosis, the treatment of infections caused by biofilm positive S.aureus isolates become difficult. The icaADBC locus and some proteins have provento be responsible for the formation of S.aureus type biofilm. The aim of this study was to investigate the relationship between the genotypic and phenotypic detection methods of biofilm formation with icaA, icaD and bap genes and phenotype expressions which are responsible for the formation of biofilm in S.aureus isolates. One hundred seventy five S.aureus isolates from various clinical specimens were included in the study. For the phenotypic detection of biofilm producing isolates Congo red agar (CRA) medium and microplate method were used. The biofilm-producing strain Staphylococcus epidermidis ATCC 35984 and S. epidermidis ATCC 12228 were used as positive and negative controls, respectively. One hundred fifty two S.aureus biofilm producing isolates were detected at least by either Congo Red agar or microplate method and all isolates were screened for icaA, icaD and bap genes by PCR. The production of polysaccharide intracellular adhesins /poly-N-acetyl-beta-1-6-glucosamine (PIA/PNAG) was also investigated in S.aureus isolates. For the detection of PIA/PNAG chemiluminescence dot-blot method was used. According to the phenotypic evaluations based on colony morphologies in CRA medium, biofilm formation were found as negative in 101 of 175 isolates (57.7%), while biofilm formation were positive in 74 (42.3%) of the isolates. As a result of quantitative evaluation by microplate method based on absorbance measurement, biofilm production was determined as negative in 34 (19.4%) specimens, moderate in 112 (64.0%) specimens and strong in 29 (16.6%) specimens. Microplate and CRA methods were incompatible with each other when compared for their biofilm production determination (p< 0.001). Among the 152 clinical isolates used to determine the presence of icaA and icaD genes responsible for the formation of biofilms, the genes were detected in 136 (89.5%) of the isolates and in the S.epidermidis ATCC 35984 strain used as a positive control. icaA and icaD genes were not detected in sixteen of the 152 (10.5%) clinical isolates and in the S.epidermidis ATCC 12228 strain used as a negative control. A weak-moderate correlation was found between icaA and icaD genes and biofilm production determined in CRA medium. A good correlation was found between icaA and icaD genes and biofilm production detected in microplate method. bap gene was determined in only one of the 152 clinical S.aureus isolates studied and in S.aureus V329 strain used as positive control. For the detection of PIA/PNAG which was synthesized by icaADBC genes, 50 clinical S.aureus isolates were used. PNAG production was determined in 42 isolates with positive icaA and icaD genes by the chemiluminescence dot-blot method, and no PNAG production was determined among eight isolates with negative ica genes. As a result, it was found that the microplate method was more sensitive and reliable for the phenotypic determination of biofilm formation in S.aureus isolates, high level of biofilm formation among clinical S.aureus isolates (about 80%), the role of icaA and icaD genes and products (PIA/PNAG) in biofilm production was determined.

[Auditory performance analyses of cochlear implanted patients]. / Koklear implant uygulanan hastalarin isitsel performans analizleri.

OBJECTIVES: The aim of this study was to analyze the auditory performance development of cochlear implanted patients. The effects of age at implantation, gender, implanted ear and model of the cochlear implant on the patients' auditory performance were investigated. PATIENTS AND METHODS: Twenty-eight patients (12 boys, 16 girls) with congenital prelingual hearing loss who underwent cochlear implant surgery at our clinic and a follow-up of at least 18 months were selected for the study. Listening Progress Profile (LiP), Monosyllable-Trochee-Polysyllable (MTP) and Meaningful Auditory Integration Scale (MAIS) tests were performed to analyze the auditory performances of the patients. To determine the effect of the age at implantation on the auditory performance, patients were assigned into two groups: group 1 (implantation age = or <60 months, mean 44.8 months) and group 2 (implantation age = or <60 months, mean 100.6 months). RESULTS: Group 2 had higher preoperative test scores than group 1 but after cochlear implant use, the auditory performance levels of the patients in group 1 improved faster and equalized to those of the patients in group 2 after 12-18 months. Our data showed that variables such as sex, implanted ear or model of the cochlear implant did not have any statistically significant effect on the auditory performance of the patients after cochlear implantation. CONCLUSION: We found a negative correlation between the implantation age and the auditory performance improvement in our study. We observed that children implanted at young age had a quicker language development and have had more success in reading, writing and other educational skills in the future.

[Investigation of siderophore, total matrix protease and elastase activity in Pseudomonas aeruginosa isolates from lower respiratory tract and extra-respiratory tract samples]. / Alt solunum yolu örnekleri ve solunum yolu disi örneklerden izole edilen Pseudomonas aeruginosa suslarinda siderofor, total matriks proteaz ve elastaz aktivitesinin arastirilmasi.

Pseudomonas aeruginosa is an important opportunistic pathogen. P. aeruginosa strains secrete several virulence factors, in the form of extracellular proteins. Adhesins, pyocyanin, proteases, hemolysins, exotoxin A and exoenzyme S are some of the virulence factors found in P. aeruginosa strains. In this study, the presence of siderophore, total matrix protease and elastase activities were investigated in a total of 157 P. aeruginosa strains isolated from lower respiratory tract (n: 81; sputum, bronchoalveolar lavage, tracheal aspirate) and extrarespiratory sites (n: 76; urine, wound, blood) of hospitalized pati ents. Chrome azurol S (CAS) agar plates were used for detection of siderophore activity. Hide powder azure was used for the investigation of total matrix protease activity and elastin congo red was used to test elastase activity. All strains gave positive reaction on CAS agar. Enzyme activities of the test strains were compared with the activity of P. aeruginosa PAO1 positive control strain. Mean total matrix protease and elastase activities were less than P. aeruginosa PAO1 activity in the test strains, however, some strains exhibited activity higher than PAO1. There was no significant difference for mean protease and elastase activities between the strains isolated from lower respiratory tract samples and the others (p > 0.05) [corrected] as well as no difference with respect to antibiotic resistance (p > 0.05) [corrected] It was found that ceftazidime and cefoperazone were the most resistant agents in both groups (67.9% and 57.9% for ceftazidime and 49.3% and 48.7% for cefoperazone, respectively). It was concluded that further in vivo studies are necessary to clarify the role of virulence factors of P. aeruginosa in the establishment of infection in different body sites.

[Biotyping of Propionibacterium acnes strains isolated from patients with acne vulgaris]. / Akne vulgaris hastalarindan izole edilen Propionibacterium acnes suslarinin biyotiplendirilmesi.

Propionibacterium acnes is the main bacterial etiologic agent in acne vulgaris pathogenesis. The rate of antibiotic resistant P. acnes isolates is less than 10% in our country. The aim of this study was to biotype P. acnes strains which were isolated from acne vulgaris patients and to investigate the biotype distribution in our region. P. acnes isolates from 64 patients (18 male, 46 female; mean age 19 +/- 3.1 years) were included in the study and biotyped by sugar-specific pH changes using sorbitol, erythritol and ribose. Results were compared with the global acne grading scores and clinical types of the patients. The frequency rates of P. acnes biotypes were found as follows; 40 strains (62.5%) were biotype I, 3 (4.7%) were biotype II, 20 (31.3%) were biotype III and one (1.6%) was biotype IV, whereas biotype V was not detected. The acne cases who were admitted to dermatology outpatient clinics mostly complained of papulopustuler and nodulocystic lesions. Therefore the detection of antibiotic resistance rates of P. acnes strains by mass screening of the community has a growing importance. Since P. acnes biotype III is the main biotype which causes the most severe acne reactions, the 31.3% rate of frequency found in our study, can not be overlooked. As a result, this data should be considered as a guide while prescribing antibiotics for the treatment of acne patients.

[Investigation of the inter-observer agreement rates for morphometric evaluation of the growth of Microsporum canis colonies]. / Microsporum canis kolonilerinin morfometrik degerlendirmesinde arastirici uyumu.

Morphometry is a newly applied method for investigation of the in-vitro growth dynamics of dermatophyte colonies. This study was undertaken to evaluate the correlation and agreement rates between the morphometric data obtained by different observers. For this purpose, five different Microsporum canis growth data were evaluated by six observers. The results of the study suggested that the agreement rates among the data obtained by different observers were low (R1 = -5.3509), while the results obtained by a single observer at different reading time points were consistent and correlated with the estimated growth rate. We thus recommend the evaluation of morphometric test results by a single observer for optimal standardization and consistency.

Anticandidal activity of Pseudomonas aeruginosa strains isolated from clinical specimens.

Pseudomonads represent the major group of non-differentiating microorganisms that produce antibiotics. The antibiotic substances produced by this group of organisms are pyocyanin, pyrolnitrin and pseudomonic acid. This study was designed to investigate the in vivo and in vitro anticandidal activity of Pseudomonas aeruginosa strains against Candida species. Forty-four P. aeruginosa strains isolated from various specimens of intensive care patients were included in the study. All P. aeruginosa strains have pyocyanin pigment. Candida albicans ATCC 10231, Candida parapsilosis ATCC 22019, Candida krusei ATCC 6258 and a clinical isolate of Candida tropicalis were used to measure the anticandidal activity of Pseudomonas strains by Kerr's method. The total inhibition rates obtained by using blood agar of C. albicans, C. parapsilosis, C. krusei and C. tropicalis were 41%, 34%, 34% and 25% respectively. When Sabouraud dextrose agar (SDA) was used, the rates were detected as 45%, 39%, 48% and 25% respectively. In the mouse model of concomitant subcutaneous infection with Candida species and P. aeruginosa no yeast were recovered from skin cultures despite 100% detection of P. aeruginosa. Pseudomonas aeruginosa strains isolated from intensive care patients showed anticandidal activity against the Candida species in the present study and this point may be important in the following and treatment of patients.