Devrim Dundar

In-Vitro Efficacy of Synergistic Antibiotic Combinations in Multidrug Resistant Pseudomonas Aeruginosa Strains

Purpose Combination antibiotic treatment is preferred in nosocomial infections caused by Pseudomonas aeruginosa (P. aeruginosa). In vitro synergism tests were used to choose the combinations which might be used in clinic. The aim of this study was to investigate the synergistic efficacy of synergistic antibiotic combinations in multidrug resistant P. aeruginosa strains. Materials and Methods Synergistic efficacies of ceftazidime-tobramycin, piperacillin/tazobactam-tobramycin, imipenem-tobramycin, imipenem-isepamycin, imipenem-ciprofloxacin and ciprofloxacin-tobramycin combinations were investigated by checkerboard technique in 12 multiple-resistant and 13 susceptible P. aeruginosa strains. Results The ratios of synergy were observed in ceftazidime-tobramycin and piperacillin/tazobactam-tobramycin combinations as 67%, and 50%, respectively, in resistant strains, whereas synergy was not detected in other combinations. The ratios of synergy were observed in ceftazidime-tobramycin, piperacillin/tazobactam-tobramycin, imipenem-tobramycin, imipenem-ciprofloxacin and imipenem-isepamycin combinations as 31%, 46%, 15%, 8%, 8%, and respectively, in susceptible strains, whereas synergy was not detected in ciprofloxacin-tobramycin combination. Antagonism was not observed in any of the combinations. Conclusion Although the synergistic ratios were high in combinations with ceftazidime or piperacillin/tazobactam and tobramycin, the concentrations in these combinations could not usually reach clinically available levels. Thus, the solution of the problems caused by multiple resistant P. aeruginosa should be based on the prevention of the development of resistance and spread of the causative agent between patients.

The schizophrenia and Toxoplasma gondii connection: Infectious, immune or both?

IntroductionRecent research has suggested a possible link between toxoplasmic agents and schizophrenia. We aimed to assess this by measuring Toxoplasma gondii-associated antibodies in schizophrenia patients and controlsMethodsWe used a commercially available enzyme-linked immunosorbent assay (ELISA) kit to measure the level of immunoglobulin G (IgG) and IgM antibodies in serum samples from schizophrenia patients (n=40) and from a group of non-schizophrenic control subjects (n=37)ResultsAmong schizophrenic patients, 16 (40%) showed IgG seropositivity and two (5%) showed IgM seropositivity. Among the control group, five (13.5%) were found have IgG seropositivity and one (2.7%) showed IgM seropositivity. In our study we found that IgG T gondii antibodies were significantly higher in schizophrenia patients compared with controlsConclusionsThis study supports the theory that toxoplasmic agents may have a role in the aetiology of schizophrenia

Emergence and spread of carbapenem-resistant Acinetobacter baumannii in a tertiary care hospital in Turkey

An intensive care unit (ICU)-based OXA-23-producing multiple-drug resistant Acinetobacter baumannii (MDRAB) outbreak was detected between October 2005 and October 2006. A total of 47 patients were infected/colonized with the outbreak strain. Clinical data were available from 37 patients. The all-cause mortality rate among the patients exposed to the epidemic strain was 35% (13/37). The outbreak strain and the resistance determinants were characterized both by microbiological methods and by molecular techniques. Cloning and sequencing experiments identified ISAbaI-associated bla(oxa-23) on the chromosome. Screening of imipenem-resistant Acinetobacter isolated from the ICU during the outbreak period with PCR identified 97 isolates as positive for the ISAbaI-bla(oxa-23) structure. Pulsed-field gel electrophoresis and plasmid analyses with selected nonrepetitive isolates revealed the clonality. Disk diffusion on cloxacillin-supplemented agar media and the real-time PCR experiments showed that outbreak isolates are overexpressing the ampC enzyme. This study highlights the occurrence of OXA-23-producing and ampC-overexpressing MDRAB in ICUs.

Macrolide and Tetracycline Resistance and emm Type Distribution of Streptococcus pyogenes Isolates Recovered from Turkish Patients

The aims of this study were to determine the susceptibilities to macrolide and tetracycline antibiotics and emm type distribution of Streptococcus pyogenes strains isolated in the Kocaeli University Hospital, Turkey. A total of 127 S. pyogenes clinical isolates were tested. Eleven (9%) isolates were resistant to erythromycin, and 23 (18%) isolates were resistant to tetracycline. Ten of the erythromycin-resistant isolates were also resistant to tetracycline. By the triple-disk test, all erythromycin-resistant isolates showed the inducible macrolide-lincosamide-streptogramin-C phenotype and harbored erm(TR) gene. tet(O) was the most common tetracycline resistance gene. Among erythromycin-tetracycline coresistant isolates, seven harbored the tet(O) gene. emm 4, emm 1, emm 2,114, and emm 89 were the most common emm types. These isolates were more susceptible to erythromycin. There was considerable emm type heterogeneity in macrolide or tetracycline resistant isolates. According to our knowledge, this is the first study in which emm type distribution is investigated in Turkey. More comprehensive studies are needed to obtain true information about the epidemiology of macrolide and tetracycline resistance and emm type distribution in Turkey.

Evaluation of immunochromatographic test for the detection of antibodies against Echinococcosis granulosus.

Background Echinococcosis in humans is a disease caused by the larvae of Echinococcus granulosus (E. granulosus) and Echinococcus multilocularis (E. multilocularis). Serological tests are valuable, especially in the clarification of unexplained clinical findings and imaging methods. For this reason, indirect hemagglutination (IHA), latex agglutination, immunoelectrophoresis, immunoblotting, immuno-enzymatic tests, indirect fluorescence antibody test (IFAT), and enzyme-linked immunosorbent assay (ELISA) are used. The purpose of this study was to investigate the value of an immunochromatographic test (ICT) specific for E. granulosus antibodies in the diagnosis of echinococcosis. Material/Methods ICT evaluated 102 cases of cystic echinococcosis, 38 cases of other parasitic diseases, and 50 healthy individuals. ELISA (DRG, Germany) that detects IgG antibodies specific for E. granulosus was used as the reference method. Results The sensitivity, specificity, and positive and negative predictive values of ICT were 96.8%, 87.5%, 98.9%, and 70%, respectively. Diagnostic value was 96.1%. No significant differences and high degrees of agreement were found between ELISA and immunochromatographic test for cystic echinococcosis. Serum samples included 4 taeniasis, 2 leishmaniasis, and 2 healthy individuals were diagnosed to be positive with immunochromatographic test. Conclusions The ability of test to give fast results without need for equipment, devices, and specific storage conditions is an advantage. This test may be used due to its advantages in endemic regions for screening and diagnostic purposes.

OXA-162, a novel variant of OXA-48 displays extended hydrolytic activity towards imipenem, meropenem and doripenem

Context: Isolation and characterization of OXA-162, a novel variant of OXA-48. Objectives: Klebsiella pneumoniae isolate with decreased susceptibility to carbapenems was recovered from a Turkish patient. This study aimed at characterizing the carbapenem resistance determinants of this isolate. Materials and methods: Antibiotic susceptibility tests, analytic isoelectric focusing (IEF), cloning and sequencing were performed. Cloned β-lactamase was purified by means of preparative gel electrophoresis and the kinetic constants were determined under initial rate conditions. Results: The identified blaOXA-162 gene was located on a ca. 45-kb plasmid carrying a transposon consisted of two IS1999-2 elements. OXA-162 differed from OXA-48 by a single amino acid substitution (Thr213Ala) which increased the catalytic efficiency (kcat/KM) of OXA-162 towards imipenem and meropenem. Also this substitution caused a gain of hydrolysis ability towards doripenem. Analysis of OXA-162 model implied that the amino acid change might generate an extension in the opening of the substrate entry site and might cause extended hydrolytic activity towards imipenem, meropenem and doripenem. Discussion and conclusion: OXA-162, a derivative of OXA-48 has enhanced catalytic properties.

Childhood urinary tract infection caused by extended-spectrum β-lactamase-producing bacteria: Risk factors and empiric therapy.

This study investigated risk factors of childhood urinary tract infection (UTI) associated with extended‐spectrum β‐lactamase (ESBL)‐producing bacteria (ESBL‐positive UTI) and evaluated antimicrobial resistance as well as empiric treatment of childhood UTI.

Epidemiological and molecular characteristics of meticillin-resistant Staphylococcus aureus in Turkey: A multicentre study

The aim of this study was to investigate the epidemiological and molecular features of clinical meticillin-resistant Staphylococcus aureus (MRSA) isolates in Turkey. MRSA isolates were collected from six regions of Turkey. The mecA and nuc genes were detected by PCR. Antimicrobial susceptibilities were determined by the disk diffusion method. Staphylococcal cassette chromosome mec (SCCmec) and staphylococcal protein A (spa) typing were performed by the sequencing method for 270 randomly selected MRSA isolates. The US Centers for Disease Control and Prevention (CDC) definition was used for epidemiological diagnosis of community-associated MRSA (CA-MRSA). Resistance rates of MRSA to ciprofloxacin, gentamicin, clindamycin, erythromycin, rifampicin, trimethoprim/sulfamethoxazole and tetracycline were 93.4%, 81.2%, 38.5%, 57.8%, 93.9%, 1.1% and 93.1%, respectively. The most frequent SCCmec type was SCCmec III (91.1%). SCCmec type IV was found in 5.2% of the isolates. The most frequent spa type was t030 (81.1%). Five isolates were CA-MRSA if only the epidemiological definition was used (5/725; 0.7%). Two isolates were defined as CA-MRSA both by epidemiological features and SCCmec typing (2/270; 0.7%). Of 14 SCCmec type IV isolates, 12 were not defined as CA-MRSA by epidemiological features. In conclusion, this is the most comprehensive multicentre study in Turkey investigating MRSA using both epidemiological and genotypic features. The CA-MRSA rate is low in Turkey. Combined use of epidemiological and genotypic methods is the most accurate approach for the diagnosis of CA-MRSA.

Relationship between phylogenetic groups, antibiotic resistance and patient characteristics in terms of adhesin genes in cystitis and pyelonephritis isolates of Escherichia coli.

Extraintestinal pathogenic Escherichia coli (E. coli) is considered as the main causative agent of urinary tract infections worldwide. The relationship between antimicrobial resistance, phylogenetic groups, patient characteristics and adhesin virulence genes are complex and not fully understood. In this study, among 146 urinary isolates of E. coli, phylogenetic groups and various adhesin virulence genes were examined with multiplex Polymerase Chain Reaction methods. Patient characteristics divided into sex, cystitis and pyelonephritis; community-acquired and hospital-acquired; complicated and uncomplicated infection. Antimicrobial resistance was also determined. The papAH gene was seen more often in pyelonephritis than cystitis and female than male patients. iha gene was more frequent in hospital-acquired infections than in community-acquired infections. sfa/focDE was more frequent in ampicillin, amikacin, gentamicin, nalidixic acid, norfloxacin, cefuroxime, ceftriaxone, cefazolin, cefotaxime, ciprofloxacin and trimethoprim/sulfamethoxazole susceptible and extended-spectrum β-lactamase (ESBL) and multi-drug resistance (MDR) negative isolates. focG was seen more often in nalidixic acid, norfloxacin, cefuroxime, ceftriaxone, ciprofloxacin susceptible and MDR negative isolates. fimH and papAH were more commonly observed in amoxicillin/clavulanic acid and cefotaxime susceptible isolates, respectively. iha and afa/draBC genes were more frequent in resistant isolates than the susceptible ones; for iha, in ampicillin, amoxicillin/clavulanic acid, nalidixic acid, cefuroxime, ceftriaxone resistant and ESBL and MDR positive isolates; for afa/draBC, in cefotaxime, cefuroxime, ciprofloxacin, trimethoprim/sulfamethoxazole resistant and ESBL and MDR positive isolates, this trend was observed. ST 131 E. coli virulence gene pattern has a direct effect on resistance profile. Isolates belong to that clonal group has MDR and commonly harbour afa/draBC and iha genes. Our findings may provide new insights into the relationships between pathogenesis, patient characteristics and resistance of E. coli UTI.

Routine Using Pattern and Performance of Diagnostic Tests for Tuberculosis on a University Hospital

Introduction:Nucleic acid amplification tests to detect Mycobacterium tuberculosis in clinical specimens are used increasingly as a laboratory tool. We aimed to investigate the routine using pattern and the effects on therapeutic decision of diagnostic tests for tuberculosis in our hospital. Methods:In this descriptive study, we investigated retrospectively the routine using pattern and the effects on therapeutic decision of diagnostic tests for tuberculosis. Patients with discordant results were clinically evaluated retrospectively by a chest physician. Samples were tested for the presence of M. tuberculosis by a smear technique, M. tuberculosis culture growth technique (Löwenstein-Jensen and/or BACTEC-960), and IS6110 polymerase chain reaction (PCR). Results:Culture positivity was 7.2% (83 of 1159 patients). In total, 198 (62.4%) were tested with PCR, acid-fast bacilli, and culture. On the basis of culture results as a gold standard, sensitivity, specificity, positive predictive value, and negative predictive value of PCR were 46%, 89%, 23%, and 93.5%, respectively. Conclusions:Selection of appropriate patients for further testing and exclusion of low-risk patients from microbiologic testing by experienced clinicians may help to optimize the positive predictive value of PCR.