Alper Tekeli

Candida carriage and Candida dubliniensis in oropharyngeal samples of type-1 diabetes mellitus patients.

The carriage of Candida dubliniensis in the oral cavities of type‐1 diabetic patients were investigated. Of 230 patients 81 (35%) had Candida spp. in their oral cavity; C. albicans was the most frequently isolated species (58%). No C. dubliniensis was found in the study population.

Aggressive bowel preparation does not enhance bacterial translocation, provided the mucosal barrier is not disrupted

PURPOSE: Prospective, randomized studies have shown that bowel preparation may adversely affect infectious complications following colonic resections. However, very little is known about the effects of bacterial translocation on these infectious complications. The aim of this prospective, randomized study was to assess the effects of bowel preparation on bacterial translocation. METHODS: A total of 82 consecutive patients undergoing elective abdominal operations were randomly assigned to four groups: control (I; n=20), mechanical (II; n=21), mechanical plus oral metronidazole (III; n=20), and polyethylene glycol preparation (IV; n=21). Patients with intra-abdominal infection, those receiving preoperative antibiotics for any reason, and those having lower gastrointestinal tract disease were excluded from the study. Peritoneal swab, ileocecal and pericolic mesenteric lymph nodes, liver wedge biopsy, portal venous blood, and peripheral blood samples were taken for culture. Patients were followed up for postoperative infectious complications. Groups were matched according to age, gender, body surface area, and Acute Physiology and Chronic Health Evaluation II scores. RESULTS: Bacterial translocation was identified by a positive culture in one patient in Group I, two in Group II, one in Group III, and three in Group IV, respectively. Differences in number of positive cultures among the groups were not statistically significant. Nine patients had major infectious complications. Only two had bacterial translocation, and the same micro-organisms grew in both patients, in one at the wound site and in the other at the cyst abscess. CONCLUSION: This study demonstrated that mechanical bowel preparation does not enhance the spontaneous occurrence of bacterial translocation in patients without any clinical signs of lower gastrointestinal tract disease.

Investigation of Panton-Valentine Leukocidin Genes and SCCmec Types in Clinical Staphylococcus aureus Isolates from Turkey

Panton-Valentine leukocidin (PVL) is an important virulence determinant of Staphylococcus aureus. The aim of this study was to investigate the prevalence of PVL genes in clinical S. aureus isolates and to determine the staphylococcal chromosomal cassette mec (SCCmec) types of methicillin-resistant S. aureus (MRSA) strains obtained from inpatients and outpatients of two hospitals in Turkey. Of the 304 S. aureus strains (230 hospital acquired [HA] and 74 community-onset [CO]), 261 were MRSA and 43 were methicillin-sensitive S. aureus (MSSA). PVL positivity was determined in 12 (1 HA and 11 community acquired) strains. Eight were MRSA, and four were MSSA. Seven of the PVL-positive strains were isolated from wound specimens, four from urine, and one from synovial fluid. SCCmec type III (93.78%) was more prevalent among HA-MRSA strains, and SCCmec type IIIB (41.18%) was more prevalent among CO-MRSA strains. Pulsed-field gel electrophoresis patterns of the PVL-positive isolates were different. Our results indicate that PVL-positive strains are able to cause infection in nearly every system without the need for additional risk factors. Our PVL-positive CO-MRSA strains carry SCCmec types other than types IV and V. Due to the presence of PVL-positive strains in the hospitals, it is important to establish appropriate infection control measures to prevent their spread in the community and in hospitals.

Urease Activity and Urea Gene Sequencing of Coccoid Forms of H. pylori Induced by Different Factors

Helicobacter pylori exists in two morphologic forms: spiral shaped and coccoid. The nonculturable coccoid forms were believed to be the morphologic manifestations of cell death for a long time. However, recent studies indicate the viability of such forms. This form of H. pylori is now suspected to play a role in the transmission of the bacteria and is partly responsible for relapse of infection after antimicrobial treatment. Urease activity of H. pylori is an important maintenance factor. Determination of urease activity and possible mutations in the DNA sequences of coccoid bacteria will hence contribute to the understanding of pathogenesis of infections, which these forms might be responsible for. In this study, our aim was to analyze the urease activity and investigate the urease gene sequences of coccoid H. pylori forms induced by different factors with respect to the spiral form. For this purpose, the urease activities of H. pylori NCTC 11637 standard strain and two clinical isolates were examined before and after transformation of the cells to coccoid forms by different methods such as exposure to amoxicillin, aerobiosis, cold starvation, and aging. The effects of these conditions on the urease gene were examined by the amplification of 411-bp ureA gene and 115-bp ureB gene regions by PCR technique and sequencing of the ureA gene. The urease activities of coccoid cells were found to be lower than those of the spiral form. ureA and ureB gene regions were amplified in all coccoid cells by PCR. Inducing the change to coccoid form by different methods was found to have no effect on the nucleotide sequence of the ureA gene. These results show that the urease gene region of coccoid H. pylori is highly protected under various mild environmental conditions.

Bevacizumab Sterility in Multiple Doses from a Single-Use Vial

Background: Recent reports have demonstrated that refrigerated bevacizumab can be stored for up to 3 weeks at 4 °C without loss of efficacy. There have been no previous reports addressing bevacizumabs sterility when stored and used as multiple doses from a single-use vial. Objective: To evaluate the sterility of bevacizumab when used as multiple doses from a single-use vial. Methods: Four groups of vials were used to simulate the storage and use conditions for bevacizumab. Each group contained 11 doses of 0.2 mL of bevacizumab. One sample from each group was cultured once each day at 37 °C for 10 days; one sample from each group was left for 15 days. MacConkey agar, blood agar, thioglycollate broth, and Sabouraud medium were used to assess bacterial and fungal growth. Results: A total of 44 samples of bevacizumab were included in this study. Each sample was placed on 4 growth media for microbial readings. All samples were found to be negative for microbial growth. No significant differences were observed among the groups. Possible limitations of this study included the number of samples for each group and in vitro design of the study, which might have affected the growth of bacterial organisms. Conclusions: Storage and multiple use of bevacizumab from single-use vials does not seem to result in microbial contamination.

Detection of Candida dubliniensis in oropharyngeal samples of Turkish HIV-positive patients.

The incidence of Candida dubliniensis in immunocomprimised patients in Turkey has not yet been determined. In this study the presence of C. dubliniensis in oral rinse samples of human immunodeficiency virus (HIV)‐positive patients and healthy controls were investigated. Phenotypic tests like inability of growth at 45 °C, colony formation on Staib agar, intracellular β‐d‐glucosidase activity, carbohydrate assimilation profiles and polymerase chain reaction with species‐specific primers (DUBF and DUBR) were carried out for differentiation of C. dubliniensis. Of the 35 patients, four (11.4%) had C.dubliniensis in their oral cavity. Antifungal susceptibility testing of these C. dubliniensis isolates showed fluconazole MICs ranging from <0.06 to 32 μg ml−1 and amphotericin B from <0.06 to 0.25 μg ml−1. One isolate was dose‐dependently susceptible to fluconazole (32 μg ml−1). This study demonstrates C. dubliniensis in HIV‐positive patients from Turkey.

Investigation of Candida dubliniensis in Candida spp.-positive hemocultures.

Candida dubliniensis is one of the Candida species which was first recognized in 1995. The yeast was misidentified because of its phenotypic similarities with Candida albicans. In this study, blood samples of patients from various departments at Ankara University Medical Faculty between January 1996 and September 2000 were investigated for distribution of Candida spp. and presence of C. dubliniensis. Ninety‐eight culture positive fungi were included in the study. Phenotypic tests for identification of C. dubliniensis and tests for differentiation of the yeast from C. albicans , such as colony morphology on Staib agar, growth at 42 °C and 45 °C, β‐glucosidase activity and carbohydrate assimilation, were carried out. Sixty‐four of the isolates produced germ tubes and chlamydospores, and none of them had the phenotypic characteristics of C. dubliniensis. Further large‐scale studies of specific patient groups are necessary to reveal the etiologic importance of this yeast.

Initial Candida dubliniensis isolate in Candida spp. positive haemocultures in Turkey between 2001 and 2004

Candida dubliniensis which was first recognized in 1995 can be easily misidentified because of its phenotypic similarities with Candida albicans. In this study blood samples of patients from various departments of Ankara University Medical Faculty between January 2001–June 2004 were investigated for the distribution of Candida spp. and the presence of C. dubliniensis. Culture positive 67 fungi were included to the study. Phenotypic tests such as chlamydospore formation, colony morphology on Staib agar, growth at 45 °C, carbohydrate assimilation profiles were investigated for identification and differentiation of C. dubliniensis from C. albicans. To confirm the results polymerase chain reaction were used for suspected C. albicans and C. dubliniensis isolates. Among 38 germ tube and chlamydospore forming isolates, 37 of them were found as C. albicans and one as C. dubliniensis. The incidence of C. dubliniensis in our hospital is still low, this is the first C. dubliniensis isolate as an agent of candidaemia reported from Turkey.

Investigation of Panton-Valentine leukocidin expressing Staphylococcus aureus colonization among children in a child care center

The presence of Panton-Valentine leukocidin expressing Staphylococcus aureus colonization was investigated with a qualitative nucleic acid hybridization assay among 122 children and 19 staff in a child care center. Genotyping of 5 Panton-Valentine leukocidin-positive isolates by pulsed-field gel electrophoresis revealed that one child and a teacher from the same class were colonized with the clonally related strains. This finding allowed us to suggest that close contact with colonized people is a risk factor for being colonized.

Biodegradation of BTEX Compounds by a Mixed Culture Obtained from Petroleum Formation Water

The biodegradation of BTEX compounds (benzene, toluene, ethyl benzene, and o,m,p-xylenes) by a mixed culture obtained from the formation of water, produced from the petroleum wells of the Turkish Petroleum Corporation (TPAO) in the Adıyaman region (southeast Turkey), and the effect of biomass concentration on the biodegradation rate of BTEX compounds, both alone and as a mixture, were investigated. The mixed culture, identified as Pseudomanas stutzeri and Vibrio mimicus, was grown on a brain heart infusion enriched medium at 30°C before its use in the biodegradation experiments. The biodegradation experiments were carried out using nonadapted, benzene-adapted, and toluene-adapted microorganisms. It was found that the mixed culture obtained degraded all BTEX compounds, both alone and as a mixture, and the overall specific biodegradation rates of BTEX compounds individually were higher with toluene-adapted microorganisms (both benzene and toluene: 4.27 mg/g biomass-day) than with the nonadapted (benzene: 0.096; toluene: 1.355 mg/g biomass-day) and benzene-adapted microorganisms (benzene: 3.4; toluene: 1.6 mg/g biomass-day). Similar results were obtained for BTEX compounds in a mixture. When the initial biomass concentration increased from 0.42 g/L to 2.34 g/L, the time required for complete biodegradation of both benzene and toluene decreased from 3 to 2 days with toluene-adapted microorganisms.