Mikrobiyol Bul
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Comparative Study
[Comparison of conventional methods and real-time multiplex polymerase chain reaction for identification and typing of Brucella isolates of human origin].
Brucellosis which is a worldwide zoonotic disease, still constitutes a major public health problem in rural areas of Turkey. The aim of the present study was to evaluate the species and biovar distribution of 187 presumptive Brucella strains isolated from patients inhabiting at the provinces in Eastern, South Eastern and Mediterranean regions over a 7-years period (from 2001 to 2007) and to compare multiplex real-time-polymerase chain reaction (M-RT-PCR) and conventional biotyping for the differentiation of three Brucella species. The isolates were identified at genus level by conventional microbiological methods and classified using the classical Brucella species biotyping scheme based on CO2 requirement for growth, urease activity, H2S production, sensitivity to basic fuchsin and thionin (20 and 40 µg/ml), lysis by Tbilisi and Berkeley phages, and agglutination with monospecific antisera for A and M antigens. ⋯ M-RT-PCR results were found to be 100% compatible with the reference conventional typing methods. Due to its high sensitivity, the M-RT-PCR assay could be a valuable tool for the rapid detection and differentiation of Brucella species in clinical samples which usually have very low bacterial load. These findings indicated that B.melitensis biovar 3 was by far the most frequent species for human brucellosis in these specific regions of Turkey and multiplex-RT-PCR seemed to be promising in the detection and differentiation of Brucella species.
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Candida species which are currently the fourth most common cause of nosocomial bloodstream infections, are associated with a significant morbidity and mortality. The aim of this retrospective case-control study which included adult patients was to determine the epidemiology of candidemia and to evaluate risk factors for the development of candidemia and mortality at a tertiary-care education hospital over a 1-year period. A total of 38 candidemia cases (23 were male; age range: 17-82 yrs; mean age: 61.4 ± 13.5 years) were identified among 22.507 patients hospitalized during the study period (January 1-December 31, 2008) and the overall incidence was found as 16.8 per 10.000 hospital admissions. ⋯ Risk factors for mortality due to candidemia in the univariate analysis were detected as no response to antifungal treatment (OR: 0.23; CI: 0.11-0.51, p< 0.001), underlying disease other than trauma (OR: 0.06; CI: 0.003-1.24, p= 0.02), and high Charlson index (OR: 0.60; CI: 0.38-0.93, p= 0.03), however those factors were not found significant by multivariate analysis. There was also a statistically significant correlation between Charlson index and treatment response (mean Charlson index was 3.5 ± 1.9 in therapy-responded patients and 4.8 ± 1.8 in non-responders; p= 0.03). Since the risk of developing candidemia was significantly higher in severely diseased patients using central venous catheter or with prolonged hospitalization, response to antifungal therapy may be insufficient, leading to higher mortality.
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Urinary system infections are usually bacterial, however, fungal etiology, particularly Candida spp. are encountered in about 10% of these infections. C.albicans is still the most frequently isolated species in candiduria. This study was aimed to identify the risk factors of candiduria and to determine species distribution of Candida which cause candiduria in hospitalized patients. ⋯ The other risk factors for candiduria found to be higher in the case group than the controls were as follows; presence of urinary system intervention (32% and 0, respectively; p= 0.000), catheter use (76% and 46.5%, respectively; p= 0.003) and immunosuppression history (24% and 9.3%, respectively; p= 0.041). However, there was no significant relationship between candiduria and history of surgical intervention, diabetes mellitus and renal failure (p> 0.05). In conclusion, rate of candiduria might be reduced by judicious antibiotic use, by implementation of guidelines for urinary catheter use, care and maintenance, and shortening the duration of ICU and hospital stay.
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Infections caused by extended-spectrum beta-lactamase (ESBL) producing Escherichia coli and Klebsiella spp. constitute severe problems. Carbapenems are commonly used to treat these infections. However, infections caused by carbapenem-resistant gram-negative bacteria show an increasing trend recently. ⋯ While two Klebsiella spp. İsolates were resistant to all of the tested carbapenems (MIC > 32 µg/ml), two E.coli isolates were resistant to ertapenem (MIC > 32 µg/ml) but susceptible to imipenem (MIC= 0.25 µg/ml) and meropenem (MIC= 0.5 µg/ml). Carbapenemase production was demonstrated by modified Hodge test in all of the carbapenem-resistant isolates. In conclusion, ESBL-producing gram-negative isolates should be routinely tested with a screening method for carbapenemase activity and confirmation tests should be performed in suspected cases.
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The majority of catheter-related bloodstream infections (CR-BSI) are associated with central venous catheters (CVCs) and most of them develop in patients staying at intensive care units (ICUs). The aim of this study was to assess the performance of different methods for the diagnosis of CR-BSI in neurology and neurosurgery ICUs of our hospital. This prospective study was carried out between January 2007 and January 2008 and all of the patients were followed daily for CR-BSI after the insertion of CVCs. ⋯ Sensitivity and NPV of the isolation method of the same microorganism from blood culture drawn through the catheter and drawn from the peripheral vein were 100%, specificity was 85% and PPV was 88% for the diagnosis of CR-BSI. Sensitivity, specificity, PPV and NPVs of Gram and drawn simultaneously from the peripheral vein and quantitative and semiquantitative cultures of the catheter tip in patients with removed catheter, were important factors in terms of diagnosis of CR-BSI. It was also concluded that AO staining could provide additional benefit in the diagnosis of CR-BSI since it has higher sensitivity, specificity, PPV and NPVs for peripheral blood cultures and catheter tip cultures compared to Gram staining.