Füsun Cömert

Colistin vs. the combination of colistin and rifampicin for the treatment of carbapenem-resistant Acinetobacter baumannii ventilator-associated pneumonia.

The aim of this study was to compare the responses of colistin treatment alone vs. a combination of colistin and rifampicin in the treatment of ventilator-associated pneumonia (VAP) caused by a carbapenem-resistant A. baumannii strain. Forty-three patients were randomly assigned to one of two treatment groups. Although clinical (P = 0·654), laboratory (P = 0·645), radiological (P = 0·290) and microbiological (P = 0·597) response rates were better in the combination group, these differences were not significant. However, time to microbiological clearance (3·1 ± 0·5 days, P = 0·029) was significantly shorter in the combination group. The VAP-related mortality rates were 63·6% (14/22) and 38·1% (8/21) for the colistin and the combination groups (P = 0·171), respectively. Our results suggest that the combination of colistin with rifampicin may improve clinical and microbiological outcomes of VAP patients infected with A. baumannii.

Characterisation of carbapenem-resistant Acinetobacter baumannii outbreak strains producing OXA-58 in Turkey

The aim of this study was to characterise the molecular epidemiology and mechanisms of carbapenem resistance of nosocomial Acinetobacter baumannii isolates in a new university hospital in Turkey. A total of 145 carbapenem-resistant A. baumannii (CRAB) isolates were collected during the period 2003-2006. All isolates were typed by amplified fragment length polymorphism (AFLP) analysis. AFLP analysis showed three predominant clusters consisting of 72, 20 and 12 clinical strains as well as some smaller clusters and 23 unique strains. The three main clonal AFLP types corresponded to three major antibiotic susceptibility patterns. One environmental isolate was found related to the major outbreak clone. The reference type strains of European clones I, II and III were also typed by AFLP and analysed for clonal similarity. Polymerase chain reaction (PCR) analysis of different carbapenem resistance genes showed that strains from each of the three main clusters as well as 79% of the remaining strains harboured the bla(OXA-58) gene. No genes encoding the metallo-beta-lactamases GIM-1, SIM-1, SPM-1, IMP-like and VIM-like or the oxacillinases OXA-24-like and OXA-23-like were detected. In conclusion, multiple clones of CRAB strains producing OXA-58-type oxacillinase were responsible for a sustained CRAB outbreak occurring in a hospital in Turkey. These isolates were not associated with A. baumannii strains of the major European clones I, II or III.

Inadequate treatment of ventilator-associated and hospital-acquired pneumonia: Risk factors and impact on outcomes

BackgroundInitial antimicrobial therapy (AB) is an important determinant of clinical outcome in patients with severe infections as pneumonia, however well-conducted studies regarding prognostic impact of inadequate initial AB in patients who are not undergoing mechanical ventilation (MV) are lacking. In this study we aimed to identify the risk factors for inadequate initial AB and to determine its subsequent impact on outcomes in both ventilator associated pneumonia (VAP) and hospital acquired pneumonia (HAP).MethodsWe retrospectively studied the accuracy of initial AB in patients with pneumonia in a university hospital in Turkey. A total of 218 patients with HAP and 130 patients with VAP were included. For each patient clinical, radiological and microbiological data were collected. Stepwise multivariate logistic regression analysis was used for risk factor analysis. Survival analysis was performed by using Kaplan-Meier method with Log-rank test.ResultsSixty six percent of patients in VAP group and 41.3% of patients in HAP group received inadequate initial AB. Multiple logistic regression analysis revealed that the risk factors for inadequate initial AB in HAP patients were; late-onset HAP (OR = 2.35 (95% CI, 1.05-5.22; p = 0.037) and APACHE II score at onset of HAP (OR = 1.06 (95% CI, 1.01-1.12); p = 0.018). In VAP patients; antibiotic usage in the previous three months (OR = 3.16 (95% CI, 1.27-7.81); p = 0.013) and admission to a surgical unit (OR = 2.9 (95% CI, 1.17-7.19); p = 0.022) were found to be independent risk factors for inadequate initial AB. No statistically significant difference in crude hospital mortality and 28-day mortality was observed between the treatment groups in both VAP and HAP. However we showed a significant increase in length of hospital stay, duration of mechanical ventilation and a prolonged clinical resolution in the inadequate AB group in both VAP and HAP.ConclusionOur data suggests that the risk factors for inadequate initial AB are indirectly associated with the acquisition of resistant bacteria for both VAP and HAP. Although we could not find a positive correlation between adequate initial AB and survival; empirical AB with a broad spectrum should be initiated promptly to improve secondary outcomes.

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

BackgroundIncreasing reports of carbapenem resistant Acinetobacter baumannii 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 A. baumannii isolates, by comparing to the validated test methods.MethodsSelected 112 clinical isolates of A. baumanii 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.ResultsMicroScan performed true identification of all A. baumannii 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%).ConclusionReporting errors for A. baumannii 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.

Identification of Candida species isolated from patients in intensive care unit and in vitro susceptibility to fluconazole for a 3‐year period

Species level identification of Candida and antifungal susceptibility testing is not generally performed in routine laboratory practice. There is limited information about the distribution of Candida species and antifungal susceptibility in Turkey. In this study, we aimed at identifying Candida isolates to species level from various samples obtained from patients treated in an intensive care unit between 2002 and 2005 and to evaluate fluconazole susceptibilities of the isolates. A total of 320 Candida isolates obtained from 270 patients were identified by conventional methods and using API (Candida and/or 20C AUX) system. Antifungal susceptibility testing was performed by broth microdilution method. Candida albicans was isolated with the highest frequency (65.6%) followed by C. parapsilosis (11.3%), C. glabrata (8.8%) and C. tropicalis (7.8%). Of all the isolates, 92.9% revealed susceptibility to fluconazole. Susceptibility to fluconazole was highest for C. albicans followed by C. parapsilosis and C. glabrata. The MIC90 values for C. albicans, C. parapsilosis, C. glabrata and C. tropicalis were 1, 2, 8 and 4 μg ml−1 respectively. Fluconazole remains effective against both C. albicans and the majority of non‐albicans Candida species. In this study, we determine the distribution of Candida species and evaluate the susceptibilities of the isolates, particularly for the azoles.

Synthesis of antibacterial amphiphilic elastomer based on polystyrene-block-polyisoprene-block-polystyrene via thiol-ene addition

A new type of amphiphilic antibacterial elastomer has been described. Thermoplastic elastomer, polystyrene-block-polyisoprene-block-polystyrene (PS-b-PI-b-PS) triblock copolymer was functionalized in toluene solution by free radical mercaptan addition in order to obtain an amphiphilic antibacterial elastomer. Thiol terminated PEG was grafted through the double bonds of PS-b-PI-b-PS via free radical thiol-ene coupling reaction. The antibacterial properties of the amphiphilic graft copolymers were observed. The original and the modified polymers were used to create microfibers in an electro-spinning process. Topology of the electrospun micro/nanofibers were studied by using scanning electron microscopy (SEM). The chemical structures of the amphiphilic comb type graft copolymers were elucidated by the combination of elemental analysis, (1)H NMR, (13)C NMR, GPC and FTIR.

First isolation of vancomycin-resistant enteroccoci and spread of a single clone in a university hospital in northwestern Turkey

Reported here is the first isolation of vancomycin-resistant Enterococcus (VRE) at a hospital in northwestern Turkey and a description of the ensuing outbreak investigation. The first isolate was obtained from a wound culture of a patient in an intensive care unit. Thereafter, a total of 205 rectal swabs, 67 skin swabs and 123 environmental samples were screened, revealing five more VRE isolates. All isolates showed similar antibiotic resistance patterns, except for two that differed regarding gentamicin resistance. The vanA gene was present in all isolates. Pulsed-field gel electrophoresis demonstrated that all isolates belonged to a single clone, with the gentamicin-resistant isolates demonstrating two-band differences. This is the first outbreak to be caused by spread of a single VRE clone in Turkey; it was successfully controlled by strict adherence to appropriate infection control practices.

The Comparison in Terms of Early Complications of a New Technique and Percutaneous Method for the Placement of CAPD Catheters

Background. Starting continuous ambulatory peritoneal dialysis (CAPD) immediately after insertion of a peritoneal dialysis catheter is essential in end-stage renal disease (ESRD). In relation to the insertion methods, various mechanical and infectious complications may arise. In this study, we aimed to compare early complications of the laparoscopic tunneling method of CAPD placement that we developed recently in order to minimize the complications, with those of the conventional percutaneous method. Subjects and method. Included in this study were 12 consecutive patients with ESRD to whom we introduced catheters for CAPD by way of laparoscopic tunneling between April 2003 and July 2003 and followed up for at least 6 months, and 30 patients to whom the catheters were placed percutaneously in the same time period with the same follow-up time. The complications seen during the first 6 months after catheter placement with these two different methods were compared. Results. In all of the subjects, dialysis was started soon after catheter placement. No per-operative morbidity was seen in any of the patients. While with laparoscopic tunneling method no mechanical problem was seen, the percutaneous method resulted in early leakage in 10%, pericatheter bleeding in 3.3%, and hernia in 3.3% of the patients. As infectious complications, peritonitis occurred as one episode/36 patient-months in laparoscopic tunneling and one episode/22.5 patient-months in percutaneous method; catheter insertion site infection was seen in none in the laparoscopic method, while one episode/90patient-months was seen with the percutaneous method. Tunnel infection did not arise in any of the subjects. Conclusion. The authors of this study think that the peritoneal tunneling method for introducing CAPD, which has been recently developed and began to be routinely used by them, is rather safe in terms of early complications.

Evaluation of the prevalence of enterotoxigenic Bacteroides fragilis and the distribution bft gene subtypes in patients with diarrhea.

The aim of this study was to determine the prevalence of enterotoxigenic Bacteroides fragilis (ETBF) in the patients with diarrhea in our region and to assess the association between diarrhea and bft gene subtypes. The presence of ETBF and bft gene subtypes were investigated in 200 stool samples from patients with diarrhea, diagnosed as gastroenteritis, which were sent to Clinical Microbiology Laboratory at Zonguldak Karaelmas University, Training and Research Hospital and in 200 stool samples from age-matched healthy subjects between April 14, 2009 and October 28, 2009. Nested - polymerase chain reaction was used to detect the presence of bft gene directly from stool samples. The bft gene subtypes were determined by PCR in case of ETBF detection. The presence of bft gene was detected in 29 (15%) of patients and 27 (14%) of control group. bft-1 and bft-2 were found in 24 and five stool samples from 29 diarrheic patients with ETBF, respectively. Among 27 control patients with ETBF, bft-1 and bft-2 were found in 24 and three samples, respectively. No bft-3 subtypes were identified in our study. ETBF was found as a single pathogen in 9% of the patients with diarrhea, while there was an accompanying pathogen in 6% of the patients. The proportion of coinfection with another pathogen among ETBF positive patients was 38%. Cooccurance with ETBF was present in nine of 18 patients with Rotavirus and two of five patients with Entamoeba histolytica. In conclusion; there was no statistically significant difference between the prevalence of ETBF in diarrheal patients and that of the control group. When the patients and controls were compared for each age group, no statistically significant difference in ETBF rates was found. There was no significant difference between groups with respect to bft subtypes; bft-1 was identified as the most common subtype. The rate of coinfection of ETBF and Rotavirus was high.

Colonic Tuberculosis Mimicking Tumor Perforation: A Case Report and Review of the Literature

Although the exact relationship between colonic tuberculosis and carcinoma of the colon is not well known, a number of studies published in the literature have reported that these two pathologies can be found at the same patient, coincidentally. Coexistence of colonic adenocarcinoma, tuberculosis, and abscess at the same anatomic location in a patient is an extremely rare condition. We herein report the second case of colonic adenocarcinoma together with colonic tuberculosis and abscess , which was diagnosed by polymerase chain reaction (PCR) identification of Mycobacterium tuberculosis of paraffin-embedded biopsy specimens, mimicking the tumor perforation.