Serkan Oncu

Comparative Activities of β-Lactam Antibiotics and Quinolones for Invasive Streptococcus pneumoniae Isolates

Background: Streptococcus pneumoniae is a leading pathogen causing pneumonia, meningitis, otitis media, bacteremia and sinusitis resulting in significant morbidity and mortality. We examined in vitro activities of five quinolones in comparison with other antibiotics against 85 invasive pneumococcal isolates. Methods: Minimal inhibitory concentrations (MICs) of penicillin G, cefuroxime, azithromycin, clarithromycin, trimethoprim-sulfamethoxazole (SXT), ciprofloxacin, ofloxacin, levofloxacin, trovafloxacin and gemifloxacin were determined using a broth microdilution method. Results: The overall rates of resistance to penicillin (46%), cefuroxime (20%), azithromycin (20%), clarithromycin (18%) and SXT (46%) were considerable. Among all of the isolates, 9 isolates (11%) were highly resistant (MIC ≧2 mg/l) and 30 isolates (35%) had intermediate resistance (MIC 0.12– 1.0 mg/l). Of the quinolones gemifloxacin and trovafloxacin had the highest activity. The penicillin resistance status of the isolates did not have any effect on the resistance pattern of new quinolones. Conclusion: The new quinolones show great potential in the treatment of invasive infections caused by both penicillin-susceptible and penicillin-resistant pneumococci.

Central venous catheter related infections: Risk factors and the effect of glycopeptide antibiotics

BackroundWe undertook a prospective study of all new central venous catheters inserted into patients in the intensive care units, in order to identify the risk factors and to determine the effect of glycopeptide antibiotics on catheter – related infections.MethodsDuring the study period 300 patients with central venous catheters were prospectively studied. The catheters used were nontunneled, noncuffed, triple lumen and made of polyurethane material. Catheters were cultured by semiquantitative method and blood cultures done when indicated. Data were obtained on patient age, gender, unit, primary diagnosis on admission, catheter insertion site, duration of catheterization, whether it was the first or a subsequent catheter and glycopeptide antibiotic usage.ResultsNinety-one (30.3%) of the catheters were colonized and infection was found with 50 (16.7%) catheters. Infection was diagnosed with higher rate in catheters inserted via jugular vein in comparison with subclavian vein (95% CI: 1.32–4.81, p = 0.005). The incidence of infection was higher in catheters which were kept in place for more than seven days (95% CI 1.05–3.87, p = 0.03). The incidence of infection was lower in patients who were using glycopeptide antibiotic during catheterization (95% CI: 1.49–5.51, p = 0.005). The rate of infection with Gram positive cocci was significantly lower in glycopeptide antibiotic using patients (p = 0.01). The most commonly isolated organism was Staphylococcus aureus (n = 52, 37.1%).ConclusionDuration of catheterization and catheter insertion site were independent risk factors for catheter related infection. Use of glycopeptide antibiotic during catheterization seems to have protective effect against catheter related infection.

Rhinocerebral mucormycosis treated with 32 gram liposomal amphotericin B and incomplete surgery: a case report

BackgroundMucormycosis (or zygomycosis) is the term for infection caused by fungi of the order Mucorales. Mucoraceae may produce severe disease in susceptible individuals, notably patients with diabetes and leukemia. Rhinocerebral mucormycosis most commonly manifests itself in the setting of poorly controlled diabetes, especially with ketoacidosis.Case PresentationA 31-year-old diabetic man presented to the outpatient clinic with the following signs and symptoms: headache, periorbital pain, swelling and loss of vision in the right eye. On physical examination his right eye was red and swollen. There was periorbital cellulitis and the conjunctiva was edematous. KOH preparation of purulent discharge showed broad, ribbonlike, aseptate hyphae when examined under a fluorescence microscope. Cranial MRI showed involvement of the right orbit, thrombosis in cavernous sinus and infiltrates at ethmoid and maxillary sinuses. Mucormycosis was diagnosed based on these findings. Amphotericin B (AmBisome®; 2 mg/kg.d) was initiated after the test doses. Right orbitectomy and right partial maxillectomy were performed; the lesions in ethmoid and maxillary sinuses were removed. The duration of the liposomal amphotericin B therapy was approximately 6 months and the total dose of liposomal amphotericin B used was 32 grams. Liposomal amphotericin B therapy was stopped six months later and oral fluconazole was started.ConclusionsAlthough a total surgical debridement of the lesions could not be performed, it is remarkable that regression of the disease could be achieved with medical therapy alone.

The microbiological diagnosis of tuberculous meningitis: results of Haydarpasa-1 study

We aimed to provide data on the diagnosis of tuberculous meningitis (TBM) in this largest case series ever reported. The Haydarpasa-1 study involved patients with microbiologically confirmed TBM in Albania, Croatia, Denmark, Egypt, France, Hungary, Iraq, Italy, Macedonia, Romania, Serbia, Slovenia, Syria and Turkey between 2000 and 2012. A positive culture, PCR or Ehrlich-Ziehl-Neelsen staining (EZNs) from the cerebrospinal fluid (CSF) was mandatory for inclusion of meningitis patients. A total of 506 TBM patients were included. The sensitivities of the tests were as follows: interferon-γ release assay (Quantiferon TB gold in tube) 90.2%, automated culture systems (ACS) 81.8%, Löwenstein Jensen medium (L-J) 72.7%, adenosine deaminase (ADA) 29.9% and EZNs 27.3%. CSF-ACS was superior to CSF L-J culture and CSF-PCR (p <0.05 for both). Accordingly, CSF L-J culture was superior to CSF-PCR (p <0.05). Combination of L-J and ACS was superior to using these tests alone (p <0.05). There were poor and inverse agreements between EZNs and L-J culture (κ = -0.189); ACS and L-J culture (κ = -0.172) (p <0.05 for both). Fair and inverse agreement was detected for CSF-ADA and CSF-PCR (κ = -0.299, p <0.05). Diagnostic accuracy of TBM was increased when both ACS and L-J cultures were used together. Non-culture tests contributed to TBM diagnosis to a degree. However, due to the delays in the diagnosis with any of the cultures, combined use of non-culture tests appears to contribute early diagnosis. Hence, the diagnostic approach to TBM should be individualized according to the technical capacities of medical institutions particularly in those with poor resources.

Escherichia coli bind to urinary bladder epithelium through nonspecific sialic acid mediated adherence

The first step in the bacterial colonization and infection of uropathogenic Escherichia coli is adherence to uroepithelium. Over 80% of all urinary tract infections are caused by E. coli. Uropathogenic E. coli express several adherence factors including type 1 and P fimbriae, which mediate attachment to the uroepithelium through specific binding to different glycoconjugate receptors. We showed that P and type 1 fimbriae are not the sole adhesins on uropathogenic E. coli and sialic acid also mediates nonspecific bacterial adherence of uropathogenic E. coli and urinary bladder epithelium.

Optimal dosage and dwell time of ethanol lock therapy on catheters infected with Candida species.

BACKGROUND & AIMS Anti-infective lock therapy is a treatment strategy in conjunction with systemic antifungal agents for the treatment of intravascular catheter infections caused by fungi. In this study, the optimal dosage and dwell time of ethanol lock solution (ELS) effective against catheters infected by Candida species were assessed. METHODS Biofilm forming isolates of Candida albicans, Candida parapsilosis and Candida tropicalis was used as the study isolates. Infected catheters were exposed to ELS at 20%, 30%, 40%, 60% and 80% strength for a variety dwell times (15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h and 24 h). Fungal eradication was evaluated by the quantitative culture techniques. RESULTS ELSs with 40% and greater strength sterilized the catheters within 30 min. Lower strength of ELSs (20% and 30%) sterilized the catheters in 24 h and 2 h, respectively. CONCLUSIONS According to the study, lock therapy with ≥40% ethanol for 30 min appear to be the optimal schedule in sterilizing Candida infected catheters. Ethanol lock therapy with such concentrations and dwell time may be a useful adjunct to systemic anti-fungal antibiotics in sterilizing (and cleaning) and eradicating fungal catheter related infections in the hope of preserving crucial central venous access.

Crimean-Congo hemorrhagic fever: An overview

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral infection that is a serious threat to humans. The disease is widely distributed in Africa, Asia, and Europe and has developed into a serious public health concern. Humans become infected through the bites of ticks, by contact with a patient with CCHF, or by contact with blood or tissues from viremic livestock. Microvascular instability and impaired hemostasis are the hallmarks of the infection. Infection in human begins with nonspecific febrile symptoms, but may progress to a serious hemorrhagic syndrome with high mortality rates. Enzyme-linked immunoassay (ELISA) and polymerase chain reaction (PCR) are the most used and specific tests for the diagnosis. The mainstay of treatment is supportive. Although definitive studies are not available, ribavirin is suggested to be effective especially at the earlier phase of the infection. Uses of universal protective measures are the best way to avoid the infection. In this review, all aspects of CCHF are overviewed in light of the current literature.Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral infection that is a serious threat to humans. The disease is widely distributed in Africa, Asia, and Europe and has developed into a serious public health concern. Humans become infected through the bites of ticks, by contact with a patient with CCHF, or by contact with blood or tissues from viremic livestock. Microvascular instability and impaired hemostasis are the hallmarks of the infection. Infection in human begins with nonspecific febrile symptoms, but may progress to a serious hemorrhagic syndrome with high mortality rates. Enzyme-linked immunoassay (ELISA) and polymerase chain reaction (PCR) are the most used and specific tests for the diagnosis. The mainstay of treatment is supportive. Although definitive studies are not available, ribavirin is suggested to be effective especially at the earlier phase of the infection. Uses of universal protective measures are the best way to avoid the infection. In this review, all aspects of CCHF are overviewed in light of the current literature.

Antimicrobial susceptibility and resistance mechanisms of methicillin resistant Staphylococcus aureus isolated from 12 Hospitals in Turkey

IntroductionMethicillin-resistant Staphylococcus aureus (MRSA) is one of the most important nosocomial pathogens and is also emerging in Turkish hospitals. The aim of this study was to determine the antimicrobial susceptibility profiles of MRSA isolated from Turkish hospitals.Materials and methodsA total of 397 MRSA strains isolated from 12 hospitals in Turkey were included to present study. Antimicrobial susceptibilities were tested using agar dilution method. Presence of ermA, ermB, ermC, msrA, tetM, tetK, linA and aac-aph genes were studied by PCR.ResultsAll strains were susceptible to vancomycin and linezolid. The susceptibility rates for fusidic acid, lincomycin, erythromycin, tetracyclin, gentamycin, kanamycin, and, ciprofloxacin were 91.9%, 41.1%, 27.2%, 11.8%, 8.5%, 8.3% and 6.8%, respectively. Lincomycin inactivation was positive for 3 isolates. Of 225 erythromycin resistant isolates 48 had ermA, 20 had ermC, and 128 had ermA-C. PCR was negative for 15 strains. Of 3 isolates with lincomycin inactivation one had linA and msrA. Of 358 gentamycin resistant isolates 334 had aac-aph and 24 were negatives. Among 350 tetracyclin resistant isolates 314 had tetM. Of 36 tetM negative isolates 10 had tetK.ConclusionMRSA isolates from Turkish hospitals were multiresistant to antimicrobials. Quinolone and gentamycin resistance levels were high and macrolide and lincosamide resistance were relatively low. Susceptibility rates for fusidic asid were high. Linezolide and vancomycin resistance are not emerged. The most common resistance genes were ermA, tetM and aac-aph. Evolution of antimicrobial susceptibilities and resistance genes profiles of MRSA isolates should be surveyed at regional and national level for accurate treatment of patients and to control dissemination of resistance genes.

The Seminal Literature of Anthrax Research

A chronically weak area in research papers, reports, and reviews is the complete identification of seminal background documents that formed the building blocks for these papers. A method for systematically determining these seminal references is presented. Citation-Assisted Background (CAB) is based on the assumption that seminal documents tend to be highly cited. Application of CAB to the field of Anthrax research is presented. While CAB is a highly systematic approach for identifying seminal references, it is not a substitute for the judgment of the researchers, and serves as a supplement.

Tetanus seroepidemiology and factors influencing immunity status among farmers of advanced age

OBJECTIVES Tetanus, which is a vaccine preventable disease, remains a significant health concern. The mortality is especially high in elderly and farming is a significant risk factor for the disease. This study evaluates the serological immunity of tetanus and the related factors, in a farmer population. METHODS This cross-sectional study was carried out in a village located in the western part of Turkey. Volunteer farmers over the age of 50 were included in the study. The study group was determined by the systematic sampling method. IgG class tetanus antibody was measured in sera of each participant. A structured questionnaire evaluating the demographic characteristics was completed by the investigators. RESULTS A total of 293 participants (55.3% female, 44.7% male) were recruited from March 2010 to June 2010. A serum protective tetanus antitoxin level (> 0.1 IU/ml) was detected in 99 out of 293 (33.9%) of participants. According to univariate analysis; advancing age, female gender, lower education, low monthly income, presence of chronic disease, absent or incomplete vaccination history or being unvaccinated in the last ten years were risk factors for insufficient tetanus immunity. After multiple logistic regression analysis, up-to-date vaccination, gender and age were the only factors that remained independently associated with immune status (p < 0.001). CONCLUSION Farmers of advancing age are a population at risk for tetanus due to their work environment and their absent or incomplete immunization to the disease. Low rates of immunity detected highlight the importance to explore strategies in order to improve immunization status in this risky population.