Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item Molecular Epidemiological Analysis of Bacillus Pseudo-Outbreak due to Contaminated Culture Tubes Containing Stuart Medium(2022) Asgin, Nergis; Kal-Cakmakliogullari, Elcin; Otlu, Baris; Ersoy, Omer F.; Celik, Betul; Basustaoglu, Ahmet; 35023676Background: It is challenging to determine whether Bacillus species other than Bacillus anthracis cause infections. Pseudo and true outbreaks of Bacillus spp. have been noted. Here, we present a molecular analysis of a Bacillus spp. pseudo-outbreak caused by contaminated culture tubes containing Stuart medium. Methods: Between January and March 2015, a high percentage of Bacillus spp. was isolated from the wound samples of inpatients at the Karabuk University Hospital, and an outbreak was suspected. Environmental and staff nasal samples were cultured aerobically, and Bacillus spp. were isolated from some of them. However, the isolation of Bacillus spp. in throat cultures of outpatients suggested contamination caused by culture tubes containing Stuart medium. We examined two lots of culture tubes used in the hospital. Although the culture tubes' expiry date and storage conditions were suitable, Bacillus spp. grew in one of these lots. A total of 47 Bacillus spp. isolated during this period were identified, and the clonal relationship among the isolates was investigated by arbitrarily primed polymerase chain reaction. Results: Twenty-seven strains were identified as Bacillus megaterium and 20 as Bacillus firmus. Of the four strains isolated from the Stuart medium, two were identified as B. firmus and the other two were B. megaterium. Two B. firmus strains isolated from the Stuart medium and two B. firmus strains obtained from the coronary intensive care environmental samples were matched and clustered within the same genotype. We recalled all culture tubes containing Stuart medium. After another brand's culture tubes were distributed, no growth was observed. It was then understood that the pseudo-outbreak source was contaminated culture tubes containing Stuart medium. Conclusions: Microbiological controls of medical materials and equipment should be regularly checked to prevent outbreaks (true or pseudo).Item Comparative in Vitro Activities of Omadacycline, Eravacycline and Tigecycline Against Non-ESBL- Producing ESBL- Producing and Carbapenem- Resistant Isolates of K. Pneumoniae(2022) Mirza, Hasan Cenk; Guclu, Aylin Uskudar; Ceviz, Gizem Ince; Basustaoglu, Ahmet; 0000-0002-8853-3893; 0000-0002-1872-028X; 36301611; F-1232-2015; AAU-6196-2020Introduction. Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae and carbapenem-resistant Enterobacte-riaceae are characterized by the World Health Organization as pathogens for which new antibiotics are urgently needed. Oma-dacycline and eravacycline are two novel antibacterials within the tetracycline class.Gap Statement. There are limited data regarding the comparison of the activities of omadacycline, eravacycline and tigecycline against K. pneumoniae isolates with different antimicrobial susceptibility profiles.Aim. Our objective was to compare the in vitro activities of omadacycline, eravacycline and tigecycline against a collection of K. pneumoniae isolates, including non- ESBL-producing, ESBL-producing and carbapenem-resistant strains.Methodology. Ninety-four K. pneumoniae isolates, including 30 non- ESBL-producing, 30 ESBL-producing and 34 carbapenem-resistant (22 carrying blaOXA-48, 12 carrying blaNDM) strains were included in the study. ESBL and carbapenemase genes were detected by conventional PCR. Omadacycline, eravacycline and tigecycline MICs were determined by the gradient diffusion method and interpreted using US Food and Drug Administration (FDA)-defined breakpoints.Results. Overall, the percentage of tigecycline-susceptible strains (97.9 %) was higher than the percentage of omadacyline-susceptible (75.5 %) and eravacycline-susceptible (72.3 %) strains. The omadacycline and eravacycline susceptibility rates were 83.3 % among non- ESBL-producing isolates and 66.7 % among ESBL-producing isolates. The most common ESBL gene detected was blaCTX-M (90 %), followed by blaTEM (50 %) and blaSHV (50 %). The omadacycline and eravacycline susceptibility rate among isolates carrying blaTEM was 33.3 %, whereas it was 100 % among isolates that do not carry blaTEM. The omadacycline and eravacycline susceptibility rates among carbapenem-resistant isolates were 76.5 and 67.6 %, respectively. The omadacycline susceptibility rates among blaOXA-48-positive and blaNDM-positive isolates were 77.3 and 75.0 %, respectively. The eravacycline susceptibility rates among blaOXA-48-positive and blaNDM- positive isolates were 68.2 and 66.7 %, respectively. One carbapenem-resistant isolate was intermediate and one ESBL-producing isolate was resistant to tigecycline.Conclusion. Overall, tigecycline was the most active tetracycline against isolates. Omadacycline and eravacycline showed excellent activity against ESBL-producing K. pneumoniae isolates that do not carry blaTEM. Omadacycline showed reasonable activity against carbapenem-resistant K. pneumoniae isolates carrying blaOXA-48 or blaNDM.Item Prevention of Candida biofilm formation over polystyrene by plasma polymerization technique(2020) Kaleli-Can, Gizem; Hortac-Istar, Elvan; Ozguzar, Hatice Ferda; Mutlu, Mehmet; Mirza, Hasan Cenk; Basustaoglu, Ahmet; Gocmen, Julide Sedef; 0000-0002-8853-3893; 0000-0002-2571-0637; F-1232-2015; AAI-8926-2021This work investigates the antifungal effect of plasma polymer films produced by low-pressure RF-generated plasma system using acrylic acid, 2-hydroxyethyl methacrylate, and diethyl phosphite (DEP). Unmodified and plasma-modified polystyrene (PS) microplate wells were tested by 30 biofilm-positive Candida spp. isolated from blood samples and two control strains using a quantitative plaque assay method. Regardless of the precursors and plasma parameters, biofilm formation was inhibited for all plasma-modified microplate wells. The most significant anti-biofilm effect was observed on PS modified by DEP at 90 W plasma power with the inhibition of all Candida species' biofilm formation.Item Evaluation of Blood Culture Practices: Use of System (Epicenter) Data(2019) Basustaoglu, Ahmet; Suzuk Yildiz, Serap; Mumcuoglu, Ipek; Karahan, Zeynep Ceren; Ogunc, Dilara; Kaleli, Ilknur; Kursun, Senol; Evren, Ebru; Ozhak, Baysal Betil; Demir, Melek; Murray, Patrick; 30683035Sepsis is a serious clinical problem and estimated to be responsible for 18 million annual deaths worldwide. Therefore, the use and the rapid processing of blood cultures are important for the transition from empiric therapy to directed therapy. The aim of this study was to assess the best blood culture practices in Turkey. We have examined the collection practices and techniques at four different hospitals, and a total of 165.443 blood culture bottles were evaluated (2013-2015). At the preanalytical phase most of the data which were important and which could support hospital quality systems/practices were not entered into the HIS and EpiCenter system. At the analytical phase loading of the bottles and removal of positive bottles primarily occurred between 6:00 and 9:00 AM but the positivity rate of the bottles showed a homogeneous distribution throughout the day. In other words, there were significant delays at processing positive blood culture bottles related to laboratory workers. The effect of education regarding best practices, transition from single bottle to two bottle cultures was successful in all hospitals. Single bottle usage decreased below 10% in all hospitals. Significantly more positive cultures were detected at multiple cultures when compared with the single bottle collection practice. In retrospective patient records, it was seen that all the laboratories reported the results of Gram staining to the clinics. However, these data were not recorded to the Epicenter. The contamination rates of Ankara Numune Hospital and Akdeniz University Faculty of Medicine Hospital are 6.2% and 5.4% respectively, contamination rates were not reported in other hospitals. The most common isolates detected in blood cultures were Escherichia coli, Klebsiella pneumoniae, Enterococcus faecium, Staphylococcus aureus, and Acinetobacter baumannii. The mean time for the detection of these organisms were less than 20 hours in the aerobic bottle and anaerobic bottles. A total of 79.6% of facultative anaerobic isolates were detected in both bottles; 9.8% were detected only in the aerobic bottles; 10.6% of the isolates were detected only in the anaerobic bottles. As a result, the educational efforts in Turkey have met with success for transition from collecting single bottle blood culture sets to two bottle blood cultures. However, further efforts are needed to increase the number of blood culture sets collected during a 24 hour's period. In addition, errors at the preanalytical, analytical and postanalytical periods (taking samples, loading bottles into the system and processing positive blood cultures) should be eliminated.