Zeynep Ceren Karahan

Genotype distribution of Candida albicans isolates by 25S intron analysis with regard to invasiveness

The aim of this study was to genotype Candida albicans strains isolated from patients with invasive and non‐invasive deep‐seated infections. For this purpose, 301 C. albicans isolates (81 invasive and 220 non‐invasive) were genotyped by using specific PCR primers designed to span the transposable group I intron of the 25S rDNA gene. Fifty‐three of the 81 invasive isolates were genotype A (65.4%), eight were genotype B (9.9%) and 20 were genotype C (24.7%), while 98 of the 220 non‐invasive isolates were genotype A (44.6%), 46 were genotype B (20.9%) and 76 were genotype C (34.5%). Genotype A was more prevalent among invasive isolates and genotypes B and C were more prevalent among non‐invasive isolates (P = 0.0046). Genotypes D and E which represent C. dubliniensis were not found. These results indicate that there may be a relationship between C. albicans genotypes and invasiveness; genotype A being more invasive than others. The presence or absence of the transposable group I intron in the 25S rDNA gene may be important in determining the invasiveness of C. albicans.

In vitro antimicrobial activity of several concentrations of NaOCl and Octenisept in elimination of endodontic pathogens

OBJECTIVE The objective of this study was to test and compare the in vitro effectiveness of sodium hypochlorite (NaOCl), and octenidine hydrochloride (Octenisept) at different concentrations in the elimination of resistant microorganisms including S. aureus, E. faecalis, and C. albicans over a range of time intervals. STUDY DESIGN A broth dilution test was performed, and the timing for irrigants to kill microbial cells was recorded. Then the samples were compared by using Kruskal-Wallis test, with significance level at P less than .05. Also minimum inhibitory concentration (MIC) of Octenisept was evaluated. RESULTS The in vitro antimicrobial effect of the most effective concentrations of the tested irrigants were ranked from strongest to weakest as follows: 100% Octenisept, 50% Octenisept, 5.25 % NaOCl, and 2.5 % NaOCl. CONCLUSIONS The antimicrobial action is related to type and concentration of the irrigants as well as the microbial susceptibility.

Investigation of Panton-Valentine Leukocidin Genes and SCCmec Types in Clinical Staphylococcus aureus Isolates from Turkey

Panton-Valentine leukocidin (PVL) is an important virulence determinant of Staphylococcus aureus. The aim of this study was to investigate the prevalence of PVL genes in clinical S. aureus isolates and to determine the staphylococcal chromosomal cassette mec (SCCmec) types of methicillin-resistant S. aureus (MRSA) strains obtained from inpatients and outpatients of two hospitals in Turkey. Of the 304 S. aureus strains (230 hospital acquired [HA] and 74 community-onset [CO]), 261 were MRSA and 43 were methicillin-sensitive S. aureus (MSSA). PVL positivity was determined in 12 (1 HA and 11 community acquired) strains. Eight were MRSA, and four were MSSA. Seven of the PVL-positive strains were isolated from wound specimens, four from urine, and one from synovial fluid. SCCmec type III (93.78%) was more prevalent among HA-MRSA strains, and SCCmec type IIIB (41.18%) was more prevalent among CO-MRSA strains. Pulsed-field gel electrophoresis patterns of the PVL-positive isolates were different. Our results indicate that PVL-positive strains are able to cause infection in nearly every system without the need for additional risk factors. Our PVL-positive CO-MRSA strains carry SCCmec types other than types IV and V. Due to the presence of PVL-positive strains in the hospitals, it is important to establish appropriate infection control measures to prevent their spread in the community and in hospitals.

Bevacizumab Sterility in Multiple Doses from a Single-Use Vial

Background: Recent reports have demonstrated that refrigerated bevacizumab can be stored for up to 3 weeks at 4 °C without loss of efficacy. There have been no previous reports addressing bevacizumabs sterility when stored and used as multiple doses from a single-use vial. Objective: To evaluate the sterility of bevacizumab when used as multiple doses from a single-use vial. Methods: Four groups of vials were used to simulate the storage and use conditions for bevacizumab. Each group contained 11 doses of 0.2 mL of bevacizumab. One sample from each group was cultured once each day at 37 °C for 10 days; one sample from each group was left for 15 days. MacConkey agar, blood agar, thioglycollate broth, and Sabouraud medium were used to assess bacterial and fungal growth. Results: A total of 44 samples of bevacizumab were included in this study. Each sample was placed on 4 growth media for microbial readings. All samples were found to be negative for microbial growth. No significant differences were observed among the groups. Possible limitations of this study included the number of samples for each group and in vitro design of the study, which might have affected the growth of bacterial organisms. Conclusions: Storage and multiple use of bevacizumab from single-use vials does not seem to result in microbial contamination.

Panton–Valentine leucocidin gene carriage among Staphylococcus aureus strains recovered from skin and soft tissue infections in Turkey

OBJECTIVES Regardless of methicillin resistance, Panton-Valentine leucocidin (PVL)-positive Staphylococcus aureus isolates are associated with various types of infections and outbreaks. Limited data exist about the PVL content of S. aureus strains in Turkey. In this multicentre study, we aimed to assess the PVL positivity and antimicrobial susceptibilities of S. aureus isolates recovered from skin and soft tissue samples of both community and nosocomial origin in the study period, 2007-08. METHODS Two hundred and forty-two [92 community-acquired (CA) and 150 hospital-acquired (HA)] isolates were included in the study. Analysis of mecA and PVL was carried out using PCR. All isolates underwent susceptibility testing according to the CLSI. RESULTS Out of 242 isolates, 77 were mecA positive. PVL was not found among methicillin-resistant S. aureus (MRSA) isolates, but 8 (5.3%) HA methicillin-susceptible S. aureus (MSSA) and 14 (15.2%) CA-MSSA, mostly isolated from furuncles (71.4%), were positive for PVL. Among PVL-positive strains, the penicillin resistance rate was 90.9%. Low resistance rates, <10%, were detected for erythromycin, fusidic acid and co-trimoxazole. PVL-positive strains showed higher rates of susceptibility to erythromycin, gentamicin and rifampicin than negative isolates. CONCLUSIONS Based on the findings of this study, infection related to PVL-carrying CA-MRSA is not at an alarmingly high level, but population-based surveillance studies should be done to determine the real status.

A cluster of Klebsiella pneumonia bacteremia in a radiation oncology ward

BACKGROUND We report an outbreak of genetically related strains of Klebsiella pneumoniae bloodstream infection. METHODS The practices that were possibly related to the outbreak were investigated through direct observation and interviews with staff by infection control team. Cultures of potential environmental sources of bacteria were obtained. RESULTS Six patients receiving intravenous medications in saline solution developed fever and shaking chills 1.5 to 4 hours after the infusion was initiated. Cultures of the blood from 4 patients yielded K. pneumoniae. Molecular characterization of K. pneumoniae done by pulsed-field gel electrophoresis revealed the same strain. CONCLUSION Although a definite source for the outbreak could not be identified, probably environmental contamination, lack of adherence to hand hygiene practices, contamination, and cross contamination led to this outbreak.

Investigation of Entamoeba histolytica and Mycobacterium spp. in biopsy specimens of patients with inflammatory bowel disease in Turkey

Intestinal amebiasis and gastrointestinal tuberculosis can mimic inflammatory bowel disease and its exacerbations clinically, pathologically, radiologically and endoscopically. In the existence of IBD and/or either one of these two pathogens, early identification and prompt treatment can improve the clinical course of the patients. The aim of this study was to investigate the presence of Entamoeba histolytica and/or Mycobacterium spp. in the first diagnostic biopsy specimens of prediagnosed IBD patients in a tertiary education hospital in Ankara, Turkey. As the differentiation of pathologic Entamoeba histolytica must be based on isoenzymatic, immunologic or molecular analysis and PCR is a rapid and reliable method for the identification of Mycobacterium spp., we investigated the presence of these pathogens in the biopsy specimens of 20 patients who were suspected to have IBD and nine controls, by using PCR-based detection methods. All of them were histopathologically diagnosed as Crohn’s disease and none of the specimens contained these two pathogens. We thought that the low prevalence of both infections in Crohn’s disease patients may have caused our negative findings and loss of pathogens could have lowered the sensitivity. Further studies with larger number of patients are needed to determine the misdiagnosis rate and coexistence of these three diseases.

Fecal Carriage of Extended‑spectrum Beta‑lactamase and AmpC Beta‑lactamase‑producing Enterobacteriaceae in a Turkish Community

Background: Community-acquired infection caused by extended-spectrum beta-lactamase (ESBL)-producing microorganisms has an increasing frequency. Aim: The aim of this study was to determine the fecal carriage of ESBL and AmpC beta-lactamase-producing Enterobacteriaceae in community and to investigate cefotaxime-M (CTX-M) genes among ESBL isolates. Materials and Methods: A total of 1402 fecal specimens which were collected from outpatients included in the study. ESBL screening, ESBL production, and AmpC beta-lactamase detection were performed. Matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) was used for identification of species. Antibiotic susceptibilities of the isolates were detected by disk diffusion method. CTX-M beta-lactamase genes were investigated by polymerase chain reaction. Results: During the study period, a total of 1402 fecal samples were analysed with ESBL screening test and 490 Enterobacteriaceae strains isolated from these samples (Escherichia coli [n = 461, 94.1%], Klebsiella pneumoniae [n = 25, 5.1%], and Enterobacter cloacae [n = 4, 0.8%]). Fecal carriage of ESBL-producing Enterobacteriaceae in the community was 34.3%. AmpC beta-lactamases were detected in 26 (5.3%), and the frequency of CTX-M was found as 96.9%. The resistance rates of the E. coli strains to fluoroquinolones, trimethoprim–sulfamethoxazole, and carbapenems were 31.2%, 33.3%, and 0%, respectively. Conclusion: The relative high prevalence of fecal carriage of ESBL-producing bacteria in community warrants further study in this field including developing policies about antimicrobial use and close monitoring of resistance patterns.

Proinflammatory biomarkers' level and functional genetic polymorphisms in periprosthetic joint infection

Objective The aims of this study were 1) to identify the level of inflammatory biomarkers interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-17, C-reactive protein (CRP), granulocyte colony-stimulating factor (GCSF), ferritin, and tumor necrosis factor (TNF)-α in serum and synovial fluid samples of patients who underwent revision arthroplasty surgery; 2) to establish the relationship between serum and synovial fluid levels; 3) to determine if any of the 11 genetic polymorphisms of TNFα, IL-1, IL-6, IL-8, IL-17, and GCSF on the encoding genes was associated with periprosthetic joint infection (PJI). Methods Synovial fluid and serum was collected from 88 patients who underwent revision arthroplasty surgery. The Musculoskeletal Infection Society definition was used to classify these patients into 2 groups: 36 PJIs and 52 aseptic failures. Synovial fluid and serum samples were tested for 9 biomarkers using a micro enzyme-linked immunosorbent assay. Genetic polymorphisms were evaluated with polymerase chain reaction and restriction endonuclease analysis. Results Synovial fluid-derived IL-1α, IL-1β, IL-8, IL-17, CRP, GCSF, TNFα, and serum-derived IL-6, IL-17, ferritin, CRP were found suitable to classify PJI and aseptic failure. In addition, IL-17 and CRP levels demonstrated a positive correlation between synovial fluid and serum. TNFα-238, IL6-174, GCSF3R, and IL1 RN-VNTR genetic polymorphisms occurred more frequently in individuals with septic failure. Conclusion Significant differences between the two groups were observed in the functional polymorphisms of the genes encoding the cytokines investigated. These differences could be interpreted as indicating that there is an association between PJI and genetic polymorphisms. Level of evidence Level III, diagnostic study.

Effects of respiratory viruses on febrile neutropenia attacks in children

Respiratory tract viruses have an important effect on morbidity and mortality in patients with febrile neutropenia (FN). The aim of this study was to determine frequency and clinical influence of viral respiratory viruses as potential etiologic agents in episodes of FN in children. A total of 100 children (62 boys, 38 girls) with 166 FN episodes were included in this prospective study. Nasopharyngeal aspirate samples were analyzed for respiratory viral agents using multiplex real-time polymerase chain reaction. The origin of the fever could be defined in 111 (67%) of the episodes. We detected viral agents in 86 (51.8%), bacterial agents in 19 (11.4%), and fungal agents in 5 (3%) of the episodes. The most common detected viruses were rhinovirus (n= 27), respiratory syncytial virus (n=17), and coronavirus (n=16). Parainfluenza virus, influenza A and B, adenovirus, human metapneumovirus, enterovirus, bocavirus and parechovirus were the remaining detected agents. More than one virus positivity occurred in 13 FN episodes. Forty-three patients had multiple FN episodes. Only four patients had the same viral agent in consecutive attacks. Respiratory symptoms (cough, nasal discharge and congestion, sneezing, wheezing), physical examination signs (rales and rhonchi) and radiological findings were significantly more common in viral agent positive patients (p < 0.05). This study showed that respiratory viruses make a substantial contribution on the etiology of FN episodes in children. Identifying viral agents may help to constitute individualized infection-management algorithms in these patients.