Istar Dolapci

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.

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.

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.

Acute pancreatitis, bacterial translocation, and different octreotide regimens: An experimental study

PurposeTo determine the effect of octreotide, octreotide with zinc, levamisole, and misoprostol on the bacterial translocation that develops in rats with acute pancreatitis (AP).MethodsA total of 36 rats were divided into six groups, each consisting of six rats. Only laparotomy was performed on the first group. Acute pancreatitis was performed on the second group. Octreotide was given to the third, fourth, fifth, and sixth groups. Octreotide, octreotide with zinc, levamisole, and misoprostol were given to groups III, IV, V, VI, respectively. Rats were euthanized 48 h after the occurrence of AP. Blood and mesenteric lymph node samples were collected for polymerase chain reaction (PCR). Pancreatic tissue and terminal ileum were obtained for histopathological examinations.ResultsThe severity of pancreatitis and mucosal damage of the terminal ileum was higher in group II than groups I, III, IV, V, and VI, histopathologically (P < 0.05). There wasn’t a significant difference with respect to OA with Zn or L or M and OA group (P > 0.05). A significant difference was found in PCR positivity in blood and mesenteric lymph node between groups I and II (P < 0.05).ConclusionsIn AP, administering octreotide alone significantly prevented the bacterial translocation by preventing mucosal damage. The zinc, levamisole, or misoprostol with octreotide did not influence the results.

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.

The Role of AcrAB–TolC Efflux Pumps on Quinolone Resistance of E. coli ST131

Escherichia coli ST131 is a cause for global concern because of its high multidrug resistance and several virulence factors. In this study, the contribution of acrAB–TolC efflux system of E. coli ST131 to fluoroquinolone resistance was evaluated. A total of nonrepetitive 111 ciprofloxacin-resistant E. coli isolates were included in the study. Multilocus sequence typing was used for genotyping. Expressions of acrA, acrB, and TolC efflux pump genes were measured by RT-PCR. Mutations in marA, gyrA, parC, and aac(6′)-lb-cr positivity were studied by Sanger sequencing. Sixty-four (57.7%) of the isolates were classified as ST131, and 52 (81.3%) of the ST131 isolates belonged to H30-Rx subclone. In ST131, CTX-M 15 positivity (73%) and aac(6′)-lb-cr carriage (75%) were significantly higher than those in non-ST131 (12.8% and 51%, respectively) (P < 0.05). The ampicillin–sulbactam (83%) resistance was higher, and gentamicin resistance (20%) was lower in ST131 than that in non-ST131 (64% and 55%, respectively) (P = 0.001 and P = 0.0002). Numbers of the isolates with MDR or XDR profiles did not differ in both groups. Multiple in-dels (up to 16) were recorded in all quinolone-resistant isolates. However, marA gene was more overexpressed in ST131 compared to that in non-ST131 (median 5.98 vs. 3.99; P = 0.0007). Belonging to H30-Rx subclone, isolation site, ciprofloxacin MIC values did not correlate with efflux pump expressions. In conclusion, the marA regulatory gene of AcrAB–TolC efflux pump system has a significant impact on quinolone resistance and progression to MDR profile in ST131 clone. Efflux pump inhibitors might be alternative drugs for the treatment of infections caused by E. coli ST131 if used synergistically in combination with antibiotics.

Effects of respiratory viruses on febrile neutropenia attacks in children

Respiratory tract viruses have an important effect on morbidity and mortality in patients with febrile neutropenia (FN). The aim of this study was to determine frequency and clinical influence of viral respiratory viruses as potential etiologic agents in episodes of FN in children. A total of 100 children (62 boys, 38 girls) with 166 FN episodes were included in this prospective study. Nasopharyngeal aspirate samples were analyzed for respiratory viral agents using multiplex real-time polymerase chain reaction. The origin of the fever could be defined in 111 (67%) of the episodes. We detected viral agents in 86 (51.8%), bacterial agents in 19 (11.4%), and fungal agents in 5 (3%) of the episodes. The most common detected viruses were rhinovirus (n= 27), respiratory syncytial virus (n=17), and coronavirus (n=16). Parainfluenza virus, influenza A and B, adenovirus, human metapneumovirus, enterovirus, bocavirus and parechovirus were the remaining detected agents. More than one virus positivity occurred in 13 FN episodes. Forty-three patients had multiple FN episodes. Only four patients had the same viral agent in consecutive attacks. Respiratory symptoms (cough, nasal discharge and congestion, sneezing, wheezing), physical examination signs (rales and rhonchi) and radiological findings were significantly more common in viral agent positive patients (p < 0.05). This study showed that respiratory viruses make a substantial contribution on the etiology of FN episodes in children. Identifying viral agents may help to constitute individualized infection-management algorithms in these patients.

Vankomisin ve Daptomisinin Koagülaz-Negatif Stafilokok İzolatlarının Oluşturduğu Biyofilm Üzerine İn Vitro Etkisi

Coagulase-negative staphylococci (CNS) are one of the primer agents of blood stream infections (BSI) and catheter-related bloodstream infections (CR-BSI) which are associated mostly with the usage of central venous catheters and, important causes of morbidity and mortality despite the usage of antibacterial and supportive treatment. It is important to determine the properties of these causative microorganisms in order to make appropriate treatment of such infections. The aims of our study were to evaluate the biofilm formation of coagulase negative staphylococci (CNS) which were causative agents of bloodstream (BSI) and catheter related bloodstream infections (CR-BSI), to determine the minimum inhibitory concentration (MIC) of planktonic forms and minimal biofilm eradication concentration (MBEC) of sessile forms for vancomycin and daptomycin and to evaluate the efficacy of these antibiotics in infections with biofilm-forming isolates in vitro. A total of 65 CoNS (n= 26 catheter colonizers, n= 28 CR-BSI, n= 11 BSI agents) were identified by conventional methods and also with BD Phoenix (Becton Dickinson, USA) and Bruker Microflex MS (Bruker Daltonics, Germany) systems. Methicillin resistance was determined by the presence of mecA gene with PCR. MIC values of vancomycin and daptomycin were investigated by broth microdilution, for daptomycin medium containing 25 and 50 μg/ml Ca++ were used. Assessment of biofilm formation and detection of MBEC were determined by microplate method. The clonal relationship was investigated by the PFGE method. A total of 65 isolates; 26 catheter colonizers, 28 CR-BSI agents and 11 BSI agents were evaluated and identified as Staphylococcus epidermidis (n= 33), Staphylococcus haemolyticus (n= 16), Staphylococcus hominis (n= 15), and Staphylococcus capitis (n= 1). 81.5% of the isolates were found to be methicillin resistant and all of them were found to be sensitive to vancomycin (MIC= 0.125-4 μg/ml) and daptomycin (MIC= 0.062-0.25 μg/ml in 25 μg/ml Ca++ and MIC= 0.031-0.50 μg/ml in 50 μg/ml Ca++ containing medium). MIC values were lower in medium containing 50 μg/ml Ca++ for daptomycin. As it is known that the efficacy of daptomycin depends on the physiological levels of Ca++, which causes conformational changes in the structure of these antibacterials. Our findings also suggested that high levels of Ca++ are needed to ensure the efficacy of daptomycin. All of the isolates produced biofilm at different strengths of positivity (n= 12/18.5% weak, n= 35/%53.8 moderate, n= 18/%27.7 strong). MBEC and MBEC/MIC values for vancomycin were found to be higher than daptomycin (p< 0.001). Strong biofilm producers had higher MBEC and MBEC/MIC, MBEC50/MIC50 ve MBEC90/MIC90 values (p< 0.05). Especially in infections with biofilm forming isolates, the detection of only MIC values are not always sufficient in the treatment of biofilm-related infections as they reflect the sensitivity of planktonic bacteria. The inconsistency between the MIC and MBEC values and the high rates of MBEC/MIC found in our study supported this prediction.The lower detection of MBEC and MBEC/MIC values of daptomycin compared to the same values of vancomycin suggested that daptomycin might be effective at lower doses than vancomycin in the treatment of biofilm infections.