Detecting imipenem resistance in Acinetobacter baumannii by automated systems (BD Phoenix, Microscan WalkAway, Vitek 2); high error rates with Microscan WalkAway

<p>Abstract</p> <p>Background</p> <p>Increasing reports of carbapenem resistant <it>Acinetobacter baumannii </it>infections are of serious concern. Reliable susceptibility testing results remains a critical issue for the clinical outcome. Automated systems are increasingly used for species identification and susceptibility testing. This study was organized to evaluate the accuracies of three widely used automated susceptibility testing methods for testing the imipenem susceptibilities of <it>A. baumannii </it>isolates, by comparing to the validated test methods.</p> <p>Methods</p> <p>Selected 112 clinical isolates of <it>A. baumanii </it>collected between January 2003 and May 2006 were tested to confirm imipenem susceptibility results. Strains were tested against imipenem by the reference broth microdilution (BMD), disk diffusion (DD), Etest, BD Phoenix, MicroScan WalkAway and Vitek 2 automated systems. Data were analysed by comparing the results from each test method to those produced by the reference BMD test.</p> <p>Results</p> <p>MicroScan performed true identification of all <it>A. baumannii </it>strains while Vitek 2 unidentified one strain, Phoenix unidentified two strains and misidentified two strains. Eighty seven of the strains (78%) were resistant to imipenem by BMD. Etest, Vitek 2 and BD Phoenix produced acceptable error rates when tested against imipenem. Etest showed the best performance with only two minor errors (1.8%). Vitek 2 produced eight minor errors(7.2%). BD Phoenix produced three major errors (2.8%). DD produced two very major errors (1.8%) (slightly higher (0.3%) than the acceptable limit) and three major errors (2.7%). MicroScan showed the worst performance in susceptibility testing with unacceptable error rates; 28 very major (25%) and 50 minor errors (44.6%).</p> <p>Conclusion</p> <p>Reporting errors for <it>A. baumannii </it>against imipenem do exist in susceptibility testing systems. We suggest clinical laboratories using MicroScan system for routine use should consider using a second, independent antimicrobial susceptibility testing method to validate imipenem susceptibility. Etest, whereever available, may be used as an easy method to confirm imipenem susceptibility.</p

Do Different Types of Adhesive Agents Effect Enamel Demineralization for Orthodontic Bonding? An In Vitro Study

(1) Objective: The aim of this study was to compare the demineralization around brackets bonded with different types of adhesive agents in a cariogenic suspension environment. (2) Methods: In the study, 60 extracted upper first premolar teeth were divided into three groups with 20 teeth in each group. In Group 1, Transbond XT Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA), in Group 2, GC Ortho Connect Light Cure Adhesive (GC Crop, Tokyo, Japan) and in Group 3, Transbond™ Plus Self Etching Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA) adhesive agents were used. In Group 1 and 2, buccal enamel surfaces were etched for 30 s, washed for 15 s and dried for 15 s. All groups were bonded with Gemini metal (3M Unitek, Monrovia, CA, USA) brackets. Gingival, occlusal and proximal enamel surfaces of the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany), and demineralization values were recorded. Measurements were performed after bracketing (T0) and after 28 days in a cariogenic environment (T1), which was renewed every 48 h. The Kolmogorov–Smirnov test was used to determine whether or not the data were homogeneously distributed, the Wilcoxon test was used for comparisons within groups, and the Mann–Whitney U and Kruskal–Wallis tests were used for comparisons between groups. (3) Results: In all groups, demineralization values on all enamel surfaces of the brackets were found to be statistically significantly higher in the T1 period than in the T0 period (p p p p > 0.05). (4) Conclusion: Significantly less occlusal enamel surface demineralization was observed in teeth in which the Transbond™ Plus Self Etching Primer adhesive agent was not applied with acid etching

HEPATITIS C VIRUS GENOTYPES IN A PROVINCE OF WESTERN BLACK-SEA REGION, TURKEY

WOS: 000284385400013PubMed: 21063977Hepatitis C virus (HCV) is one of the significant causes of hepatitis, cirrhosis and hepatocellular carcinoma all throughout the world. There are six genotypes and more than 50 subtypes of HCV. HCV genotyping is of crucial importance in the determination of the treatment protocols and the follow-up of the clinical course since treatment success is low and the duration of treatment is longer in HCV genotype 1 infected cases. The aim of the present study was to evaluate the HCV genotype profiles of the patients with chronic hepatitis C in Zonguldak, providing the first data about HCV genotypes from western Black-Sea region, Turkey. The HCV genotypes of 44 patients (26 female, 18 male; age range: 29-89 years, mean age: 60.05 +/- 10.81 years) with positive anti-HCV antibody and HCV-RNA results, admitted to the hospital between May 2007 and July 2009, were retrospectively evaluated and included in the study. Alanine aminotransferase (ALT) levels of the patients were between 8-160 IU/L (mean 63.99 +/- 37.15 IU/L) and the aspartate aminotransferase (AST) levels were between 17-160 IU/L (mean 62.77 +/- 36.75 IU/L). HCV antibody was determined by ELISA method (Abbott Laboratories, USA), and HCV-RNA was determined by two commercial real-time polymerase chain reaction systems [Cobas Taqman (Roche Diagnostic, USA) and Rotor-Gene 6000 (Corbett Research, USA)]. The genotyping was performed by a reverse hybridization based method, Versant (R) HCV Genotype Assay (LiPA) 2.0 (Bayer Health Care, Belgium). HCV genotypes could not be determined for 5 (11.4%) patients since HCV-RNA levels were low. Genotyping could be performed for 39 (88.6%) patients and 38 (97.4%) had genotype 1b and one (2.6%) patient had genotype la. In conclusion, in concordance with the other studies conducted in our country, genotype 1b was found to be the most prevalent genotype in patients from our region

EVALUATION OF REDUCED SUSCEPTIBILITY TO VANCOMYCIN AMONG MRSA STRAINS ISOLATED FROM CLINICAL SPECIMENS

WOS: 000277896300021PubMed: 20549970In this study, a total of 390 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimens between April 2004 and June 2008, in a university hospital in Zonguldak (located at Black Sea region), Turkey, were evaluated retrospectively for reduced susceptibility to vancomycin Brain heart infusion (BHI) plates containing 4 and 6 mu g/ml of vancomycin were used to screen for vancomycin intermediate S aureus (VISA) strains Additionally, vancomycin minimal inhibitory concentrations (MIC) of the isolates were determined by agar dilution method No growth was observed on the screen plates after 24 and 48 hours of incubation None of the isolates revealed MIC values equal to or higher than 2 mu g/ml, MIC(90) and MIC(50) values were 1 mu g/ml Although VISA isolates were not detected in this study, no data was obtained for heterogeneous VISA isolates since macro-E test or population analysis were not performed It was concluded that systematic surveillance of MRSA isolates is of particular importance to investigate the presence of VISA/hVISA isolates which may lead to treatment failures and hospital epidemic

Fecal Carriage of Extended Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli and Klebsiella spp. in Children in Zonguldak

WOS: 000488951800011Introduction: The aim of this study was to determine the prevalence of fecal carriage of extended-spectrum beta-lactamase (ESBL)-producing bacteria, ESBL enzyme types, and risk factors affecting colonization in children. Materials and Methods: Stool specimens of 0-15 years old children admitted to the pediatric outpatient clinic for any reason between October 2012-December 2013 were evaluated. Demographic data of the patients were collected through a questionnaire. Patients samples were cultured on selective EMB agar plates. The presence of ESBL was investigated by double disc synergy test and agar gradient test was used when necessary. Enzyme types of the isolates were determined by polymerase chain reaction (PCR). Results: The prevalence of fecal carriage was determined as 33% (150 of 454). Of the 154 ESBL-producing bacteria, 142 (92.2%), 11 (57.1%), and 1 (0.6%) were E. coil, K. pneumoniae and K. oxytoca, respectively. Of the ESBL-producing bacteria, 92.8% were positive for bla(CTX-M)genes. Of the bla(CTX-M) gene-positive isolates, 81.1% were positive for bla(CTX-M-)(15)( )and 94.4% were positive for bla(CTX-M-3) genes while 62.5% isolates were positive for both bla(CTX-M-3) and bla(CTX-M-15) genes. No significant association was demonstrated between carriage rates and the questioned risk factors. Conclusion: A high rate (33%) of fecal carriage of ESBL bacteria was found in the child population of Zonguldak. No significant association was demonstrated between carriage rates and the questioned risk factors. Predominant beta-lactamase enzyme types were CTX-M group while CTX-M-3 and CTX-M-15 were the most common enzyme types

Synthesis, characterization, and antibacterial activity of metal nanoparticles embedded into amphiphilic comb-type graft copolymers

The synthesis, spectroscopic characterization, and antimicrobial efficiency of gold and silver nanoparticles embedded in novel amphiphilic comb-type graft copolymers having good film-forming properties have been described. Amphiphilic comb-type graft copolymers were synthesized by the reaction of chlorinated polypropylene (PP) (M w = 140,000 Da) with polyethylene glycol (PEG) (M n = 2,000 Da) at different molar ratios. Metal nanoparticles embedded graft copolymers were prepared by reducing solutions of the salts of silver or gold and the copolymer in tetrahydrofuran. The optical properties of the metal nanoparticle embedded copolymers were determined by using UV–visible spectroscopy. Surface plasmon resonance (SPR) of the gold and silver nanoparticle embedded copolymers in toluene was observed at a maximum wavelength (λmax) of 428 and 551 nm in the UV–VIS absorption spectra, respectively. The average particle diameters of the gold and silver nanoparticles were found to be 50 nm from the high resolution scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Amphiphilic polymer films containing silver and gold nanoparticles were found to be highly antimicrobial by virtue of their antiseptic properties to Escherichia coli and Staphylococcus aureus

Causative Agents of Intravenous Catheter-Related Infections and Their Antibiotic Susceptibilities

WOS: 000287635700011PubMed: 21341163Intravenous catheterization can lead to colonization as well as a broad spectrum of infections ranging from catheter site infections to catheter-related blood stream infections (CRBSIs). The aim of this study was to evaluate the distribution of causative agents and their antibiotic susceptibility patterns in CRBSIs and catheter site infections along with the colonization rates and colonizing microorganisms in Zonguldak Karaelmas University Hospital, Turkey. The results of cultures from catheter tips and/or intracatheter blood cultures and simultaneously taken peripheral blood cultures were sent to medical microbiology laboratory and were retrospectively investigated for 201 patients hospitalized between September 2007 and September 2009. The catheter tips were cultured by semi-quantitative and quantitative culture methods. Blood cultures from the catheters and peripheral veins were performed in BACTEC 9120 (Becton Dickinson, USA) blood culture systems. The antibiotic susceptibility tests were done by Kirby-Bauer disk diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Out of 201 patients included, 28 (13.9%) had CRBSIs and 13 (6.4%) had catheter site infections while colonization was defined for 55 (27.3%) patients. Of 28 patients with CRBSIs, Acinetobacter spp. were isolated from 11 including five carbapenem-resistant strains, methicillin-resistant coagulase-negative staphylococci (MRCNS) from eight, methicillin-susceptible coagulase-negative staphylococci (MSCNS) from two, Klebsiella pneumoniae from two patients and one of each patient's cultures yielded methicillin-resistant Staphylococcus aureus (M RSA), carbapenem-resistant Pseudomonas aeruginosa, Enterococcus spp., Escherichia coli and MRCNS + Enterococcus faecium. Of 13 patients with catheter site infections, five MSCNS, two methicillin-susceptible S.aureus (MSSA), two E.coli, and one of each K.pneumoniae, MRCNS, Enterococcus spp., K.pneumoniae + P.aeruginosa were isolated. No resistance to vancomycin and teicoplanin were detected among the staphylococci isolated from CRBSIs and catheter site infections. The distribution of the 55 colonizing microorganisms were as follows; 18 MSCNS, 18 MRCNS, four Acinetobacter spp., five K.pneumoniae, three E.coli, two MSSA, and one of each MRSA, P.mirabilis, P.aeruginosa, Corynebacterium spp., Candida albicans. In this study, the predominant microorganism isolated from CRBSIs was Acinetobacter spp., followed by coagulase-negative staphylococci. This unexpected distribution of the agents was related to the Acinetobacter spp. that have gained endemic potential following an Acinetobacter outbreak in our hospital in 2006. We emphasize that it is critical for any individual hospital to assess periodically the distribution and susceptibility profiles of isolates obtained from catheter-related infections to set out rational empirical treatment strategies

Evaluation of the Demineralization Development around Different Types of Orthodontic Brackets

The aim of this study was to compare the demineralizations of the enamel surfaces around different types of orthodontic brackets in an artificial cariogenic environment. A total of 90 extracted human maxillary first premolar teeth were used in this in vitro study. The teeth were divided into 6 groups, 5 study and 1 control, each consisting of 15 samples. Victory metal, Gemini metal, Clarity self-ligating ceramic, APC Clarity Advanced ceramic and Clarity Advanced ceramic brackets (3M Unitek, Monrovia, Calif) used in the study groups were bonded to the teeth with the direct technique. The gingival, occlusal and proximal enamel surfaces adjacent to the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany) (T0). Then, the teeth were placed in a cariogenic suspension environment containing Streptococcus mutans, sucrose and artificial saliva. The teeth were removed from the cariogenic suspension at the end of 28 days. Enamel surfaces were remeasured with DIAGNOdent and the values were recorded (T1). Whether the obtained data were homogeneously distributed or not was determined by the Kolmogorov&ndash;Smirnov test, within-group comparisons were performed with the Wilcoxon test, and between-group comparisons were performed with Mann&ndash;Whitney U and Kruskal&ndash;Wallis tests. Significance level was accepted as p &lt; 0.05. In all groups, the demineralization values of the enamel surfaces in the gingival, proximal and occlusal surfaces adjacent to the brackets were significantly higher in the T1 period than in the T0 period (p &lt; 0.05). In the T1 period of Gemini metal, Clarity self-ligating ceramic and Clarity advanced ceramic bracket groups, the demineralization values of the proximal enamel surfaces were found to be significantly higher than the Victory metal and APC Clarity Advanced ceramic bracket groups (p &lt; 0.05). In the T1 period, the demineralization values of the occlusal enamel surfaces of the Victory metal, APC Clarity Advanced ceramic bracket groups and control group were significantly lower than the Gemini metal, Clarity self-ligating ceramic and Clarity Advanced ceramic bracket groups (p &lt; 0.05). Significant increases in enamel demineralization values were observed as a consequence of increased retention areas for microbial dental plaque on enamel surfaces adjacent to the bracket. Considering the importance of minimizing enamel demineralization in fixed orthodontic treatments, less enamel demineralization in Victory metal and APC Clarity Advanced ceramic bracket groups showed that these brackets can be preferred in patients with poor oral hygiene

THROMBOCYTE AND ERYTHROCYTE INDICES IN SEPSIS AND DISSEMINATED INTRAVASCULAR COAGULATION

WOS: 000296765600010Sepsis is the inflammatory response against infection. The existence of DIC during sepsis indicates a poor prognosis and coagulation abnormalities and thrombocytopenia may exist. The aim of this study was to investigate platelet and erythrocyte indices in sepsis patients with DIC and without DIC. In both groups coagulation tests, platelet count and indices, erythrocyte count and indices were retrospectively analysed. In the sepsis plus DIC patients the prothrombin time and D-dimer values were found significantly higher and fibrinogen, platelet and plateletcrit were found significantly lower than in the sepsis without DIC group. The ana lysis of mean platelet volume, platelet distribution width, erythrocyte count and indices revealed no significant differences between the two groups. These results showed us that the depression of bone marrow in septic patients with DIC and without DIC did not differ. The activation of the coagulation system might probably be the cause of thrombocyte depletion in DIC