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Yayın Blood Culture Positivity: Is It Pathogen or Contaminant?(ANKARA MICROBIOLOGY SOC, 2013) Balikci, Ahmet; Belas, Zeliha; Eren Topkaya, AynurBlood culture is the gold standard for diagnosis of bloodstream infections. Many studies have shown that rapid isolation and identification of the microorganisms in blood culture and initiation of early antimicrobial therapy are critically important to reduce the mortality rate. It was found that the rate of contamination in blood cultures is increasing with automated systems developed to facilitate the growth of microorganism and tracking positivity. It is more difficult to interpret a positive blood culture result especially in the case of having only one sample bottle. In this study the effect of growth time observed in the automated blood culture systems was evaluated in terms of interpretation of blood culture results as being pathogens or contaminants. A total of 1201 blood cultures tested in BACTEC 9120 (Becton Dickinson, USA) system in Maltepe University Hospital Medical Microbiology Laboratory, Istanbul, Turkey during one-year period were included in the study and growth times were recorded for positive bottles. The decision about the growth as being a pathogen or contamination was made by considering the clinical condition of the patient, the number of positive blood cultures and the results of inflammation markers (white blood cell counts, procalsitonin and CRP levels). Of the blood cultures 290 (24%) yielded positive results and 73% (212/290) of them were evaluated as pathogens, while 27% (78/290) were identified as contaminants. The mean detection time for clinically significant isolates was 17.87 hours and for contaminants was 40.56 hours. The difference between the growth time of pathogens and contaminants was found statistically significant (p< 0.0001). With regard to all positive results, it was detected that 66% of the bacteria grew within the first 24 hours. While 29.6% of the pathogens grew within 12 hours, none of the contaminants grew during that time. The evaluation of growth time among staphylococci in terms of methicillin resistance revealed that methicillin- resistant staphylococci grew later (26 hours) than the susceptible ones (11 hours) both in the pathogen group and the contaminant group (p< 0.01). The data of our study emphasized that, the growth time detected in blood culture systems had a critical role in estimating whether the isolated microorganism is a pathogen or a contaminant, especially in case of lack of more than one blood samples. It was concluded that, the bacterial growth detected within the first 24 hours most probably indicated the microorganism as pathogen, while blood culture positivity detected after 48 hours strongly pointed out that it was contaminant. However, it should be considered that methicillin-resistant staphylococci needed much longer time than 24 hour for growth, both as pathogens or contaminants.Yayın Evaluation of mycobacterial microscopy and culture results of Sureyyapasa Chest Diseases and Chest Surgery Training and Research Hospital: A 3-year analysis(TURKISH ASSOC TUBERCULOSIS & THORAX, 2016) Akduman Alasehir, Elcin; Balikci, Ahmet; Partal, Mualla; Catmabacak, Gulay; Yaman, GorkemIntroduction: Effective diagnosis of tuberculosis is of great importance for transmission control and treatment success. The purpose of this study is to evaluate microscopic examination results of Ehrlich-Ziehl Neelsen (EZN) and Auramine-Rhodamine staining methods and automated BACTEC MGIT 960 (TM) system and Lowenstein-Jensen (L-J) culture results of various clinical samples in the light of recent data from the world and Turkey. Materials and Methods: Specimens that were sent from various clinics to Sureyyapasa Chest Diseases and Chest Surgery Training and Research Hospital Microbiology Laboratory from January 2012 to December 2015 were evaluated retrospectively. Results: From a total of 62456 samples; 60923 (97.5%) were pulmonary and 1533 (2.5%) were non-pulmonary samples, especially pleura. 2853 (4.6%) Acid-resistant bacilli (ARB) positivity was detected and mycobacterial culture positivity was in total 12.2%. 7076 (93%) and 535 (7%) mycobacteria other than tuberculosis (MOTT) strains were isolated. In 356 specimens the cultures were negative in despite the positive ARB results. Considering mycobacterial culture as the gold standard; the sensitivity, specificity, positive and negative predictive values of ARB microscopy were 32.8%, 99.4%, 87.5% and 91.4%, respectively. The contamination rates in total were within acceptable limits being 2.7% for L-J and 3.8% for MGIT. Conclusion: Analysis of our data indicated that the sensitivity of microscopy is low and it should be evaluated together with the mycobacterial culture to rule out tuberculosis infection. With the use of fluorescent staining and also L-J and MGIT broth together for routine culture since 2013; ARB false negativity rate was observed to fall to 51.7% from 74.1% compared to the years. The follow-up of data such as the sensitivity of microscopy, culture positivity, false-positivity and false-negativity rates and contamination values is of great importance in terms of assessing compliance with laboratory quality standards and contributing to the surveillance studies.Yayın A Frequently Overlooked Bacteria in Clinical Microbiology Laboratories: Arcanobacterium haemolyticum(ANKARA MICROBIOLOGY SOC, 2011) Balikci, Ahmet; Topkaya, Aynur E.; Belas, ZelihaArcanobacterium haemolyticum, previously known as Corynebacterium haemolyticum, is a facultative anaerobic, gram-positive bacillus with negative catalase and positive CAMP inhibition test results. It may be the causative agent of about 0.5-3% of acute bacterial pharyngitis especially in children and young adults. Since growth of A.haemolyticum is usually inhibited by flora members and since it slowly develops hemolysis in sheep blood agar and its colony morphology resembles beta-hemolytic streptococci, it is frequently overlooked in the evaluation of throat cultures. The aims of this study were to investigate the isolation frequency of A.haemolyticum from the throat cultures of pediatric patients by using both sheep and human blood agar media, and to evaluate the performances of those media for the identification of A.haemolyticum. A total of 355 patients (median age: 7 years) who were admitted to pediatric outpatient clinics with the symptoms of tonsillopharyngitis between March-July 2010 period, were included in the study. Swab samples obtained from tonsils and posterior oropharynx were inoculated into a divided plate which contained 5% sheep blood agar in one half and 5% human blood agar in the other half. After incubation in 5% CO(2) at 37 degrees C, the beta-hemolytic colonies with a microscopic morphology of gram-positive bacilli were further evaluated on 24, 48 and 72(th) hours. Identification of A.haemolyticum was based on negative catalase test, positive reverse CAMP test and biochemical characteristics obtained by API-Coryne (bioMerieux, France) identification system. In our study, beta-hemolytic colonies were detected in the throat cultures of 56 (16%) patients, of which 14% (49/355) were identified as beta-hemolytic streptococci (46 group A, 2 group G, 1 group C), and 2% (7/355) were identified as A.haemolyticum. All of the A.haemolyticum isolates were characterized by the production of beta-hemolysis in human blood agar at 24 hours, while the beta-hemolysis generation time in sheep blood agar was 48 hours for four isolates and 72 hours for three isolates. A.haemolyticum was identified in 2% of children with tonsillopharyngitis during the five months study period in spring/summer. All of the strains were isolated at human blood agar in 24 hours. Thus, in order to isolate A.haemolyticum in routine throat cultures, sheep blood agar plates together with human blood agar plates should be used in clinical microbiology laboratories.Yayın The seroprevalence of hepatitis A in Istanbul, Turkey(MARMARA UNIV, FAC MEDICINE, 2017) Karadeniz, Asli; Akduman Alasehir, Elcin; Yesilbag, Zuhal; Balikci, Ahmet; Yaman, GorkemObjective: Hepatitis A, a leading cause of enterically transmitted acute viral hepatitis throughout the world, has changed its pattern in developing countries. The objective of this study is to determine the current seroprevalence of hepatitis A virus (HAV) for different age groups in Istanbul, Turkey. Materials and Methods: Serum samples of 3,868 patients, which had been previously taken, were used to determine anti-HAV IgG levels by the microparticle enzyme immunoassay (MPEIA) method (Architect SR i1000 and i2000, Abbott Diagnostics, Germany) between January 2011 and December 2013. Results: The prevalence of total anti-HAV antibodies was 64.8% for all patients. Among the 3,868 serum samples tested, 54% were from male patients and 46 % were from female patients. Seropositivity rates among the age groups were determined and anti-HAV antibody positivity rates were 55% for the 0-16 age group; 47% for the 17-30 age group; 73.5% for the 31-45 age group and the seroprevalence increased significantly from 50% (972/1944) in 0 to 30 years old to 89% in patients older than 46 years. Conclusion: The low seronegativity rates in young adults, show this group to be at high risk of acquiring an HAV infection. The results support the routine vaccination of children and the seronegative young adults against HAV.Yayın Serotypes and Antimicrobial Susceptibilities of Invasive Group A Streptococci Identified in Eastern Black Sea Region of Turkey(ANKARA MICROBIOLOGY SOC, 2011) Bayramoglu, Gulcin; Topkaya, Aynur E.; Balikci, Ahmet; Aydin, FarukFrequency of invasive group A streptococcus (GAS) infections is increasing worldwide in recent 20 years. Serotypes responsible for these clinical manifestations and their antibiotic susceptibilities should be known in order to establish preventive measures and initiate appropriate treatment. This study was aimed to determine the serotypes, antibiotic susceptibilities and inducible clindamycin resistance among invasive GAS isolated between 2006-2009 period. A total of 22 GAS strains isolated from clinical samples [sterile body fluids (peritoneal, pleural, pericardial, joint and cerebrospinal fluids), blood, tissue biopsy] of the patients (14 male, 8 female; age range: 3-82 years, median age: 59) who admitted to Karadeniz Technical University Faculty of Medicine, Farabi Hospital located in Trabzon province (Eastern Black Sea Region of Turkey), between March 2006 and March 2009 were included in the study. GAS serotypes were determined by the investigation of serum opacity factors (SOF), T proteins and M proteins. SOF production was investigated by microplate method using human serum and SOF types were determined by SOF-inhibition test using specific antisera. T protein types were detected by agglutination method using polyvalent anti-T sera, and M serotypes were detected by capillary precipitation method using M antisera. Antimicrobial susceptibility tests were performed by disk-diffusion method according to CLSI recommendations. SOF were positive in 9 (41%) samples. Use of T antiserum yielded T (n= 8) and U (n= 7) types and M antiserum M1 (n= 4) and M2 (n= 3) types. The overall antibiotic susceptibility rate of the isolates was 68% (15/22) and overall resistance rate was 32% (7/22). All of the GAS strains were found susceptible to benzylpenicillin, ceftriaxone, vancomycin, levofloxacine and linezolid, however 9 (41%) were intermediate susceptible to tetracycline and 1 (4.5%) was intermediate susceptible to erythromycin. Four (18%) strains were found resistant to tetracycline, while three strains (13.5%) were found resistant to chloramphenicol. Inducible clindamycin resistance was found positive only in one strain. The serotypes determined in this study indicated that 33% of our invasive serotypes were covered by the hexavalent vaccine and 62% by the 26-valent vaccine. Multi-center surveillance studies are required to determine the serotype distribution of invasive GAS in Turkey and to provide valuable information for the development of appropriate vaccines in our country.
