Banu Kaskatepe

The aim of this study was to investigate and compare in detail both the antifungal activity in vitro (with planktonic and biofilm-forming cells) and the essential oil composition (EOs) of naturally growing (OMN) and cultivated (OMC) samples of Origanum majorana L. (marjoram). The essential oil composition was analyzed using GC-MS. The major constituent of both EOs was carvacrol: 75.3% and 84%, respectively. Both essential oils showed high antifungal activity against clinically relevant Candida spp. with IC50 and IC90 less than or equal to 0.5 µg mL−1 and inhibition of biofilm with a concentration of 3.5 µg mL−1 or less. Cultivated marjoram oil showed higher anti-biofilm activity against C. albicans. In addition, OMC showed greater inhibition of germ-tube formation (inhibition by 83% in Spider media), the major virulence factor of C. albicans at a concentration of 0.125 µg mL−1. Both EOs modulated cell surface hydrophobicity (CSH), but OMN proved to be more active with a CSH% up to 5...

Introduction: There are limited treatments options for carbapenem resistant Enterobacteriaceae (CRE) species and especially colistin, fosfomycin and tigecyclin are used for treatment. Therefore, in this study, we aimed for determining the rates of antibiotic susceptibility against colisting, fosfomycin and tigecyclin in CRE isolates with microdilution method. Material and Method: In our study, a total of 63 isolates, which were isolated from blood, urine and tracheal aspirate samples. Bacteria identification of the isolates was made with MALDI-TOF MS (Bruker Biotyper; Germany) device. Imipenem, meropenem and ertapenem susceptibilities were determined with the gradient strip test (Liofilchem, Italy) method and genotypic properties were determined with the PCR method. Colistin (0.06-32 μg/ml), fosfomycin (0.06-32 μg/ml) and tigecyclin (0.25-256 μg/ml) M?K values were determined with the microdilution method. Results: Of the isolates included in the study, 60 isolates (95.24%) were def...

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are a growing concern for public health resulting in increase in morbidity, length of hospital stay, and cost of treatment. MRSA nasal swab screening may give clinicians additional information for decision of empiric antimicrobial agents. While increasing antibiotic resistance leads to new treatment approaches, bacteriophages are one of the most promising methods for these alternatives. It was aimed to determine the effectiveness of bacteriophages against MRSA isolates. Nasal swab samples were collected from outpatients without any evidence of infection who applied to Hatay, Mersin and Gaziantep family and immigration health centers. A series (35) were isolated from Turkish patients, and G series (64) were isolated from Syrian immigrants. Methicillin resistance was determined phenotypically and genotypically. Also, antibiotic susceptibilities of all isolates were determined against erythromycin, clindamycin, gentamicin, linezolid, rifampicin, and mupirocin. The total antimicrobial resistance rates of isolates were found to be 11%, 28%, 8%, 5%, 16%, 19%, and 29% respectively. The high susceptibility rate against ciprofloxacin (88.8%) was remarkable. The overall susceptibility of MRSA strains to ENKO, INTESTI, PYO, SES, and staphylococcal bacteriophages was 67.7%, 55.5%, 53.5%, 61.6% and 44.4%, respectively. The antibiotic susceptibility rates (except erythromycin) and efficacy of bacteriophages were higher in group A. Considering that high efficacy rates were not achieved in the study and the sensitivity rates of Turkish isolates to all phages were found to be higher than those of Syrian isolates, searching for phages in the geographic regions where the pathogen is common may be helpful to obtain suitable phages for treatment.

Interest in the production of exopolysaccharides by microorganisms has increased in the recent years. Using low-cost product is the main step of microbial production to reduce cost and compete with chemical production. In this work, EPS production of Streptococcus thermophilus isolates from yogurt (S2), kefir (S3), and S. thermophilus ATCC 19258 (S1) isolate which was used as control strains were investigated by using different fruit pulps. S. thermophilus isolates were identified by morphological and 16S sequence analysis. The amount of EPS obtained was measured spectrophotometrically using glucose as standard with phenol sulfuric acid method. All three isolates produced higher amounts of EPS on M17 medium than Nutrient medium. When the fruit pulp was added to the medium, EPS production increased in all three isolates. When different nitrogen sources were added together with fruit pulp juice, EPS production increased. The highest amount of EPS produced by ATCC 19258 strain (21.570 mg/L) and S3 isolate (29.131 mg/L) is the medium where mixed fruit pulp juice and nitrogen source is tryptophan. It has been shown that EPS production is increased by adding fruit pulps to the prepared media. It is thought that apricot pulp can be a good alternative in EPS production especially in the evaluation of wastes. Also, antiquorum sensing activity of the highest amount EPS was determined by using Chromobacterium violaceum CV026 strain and found effective on violacein pigment inhibition and C6-AHL production of biosensor strain.

Background: The benzazole nucleus is found in many promising small molecules such as anticancer and antibacterial agents. Bendamustine (Alkylating agent), Nocodazole (Mitotic inhibitor), Veliparib (PARP inhibitor), and Glasdegib (SMO inhibitor) are being clinically used as anticancer therapeutic which bear benzimidazole moiety. Based on the principle of bioisosterism, in the present work, 23 compounds belonging to 2-(3,4-dimethoxyphenyl)benzazoles and imidazopyridine series were synthesized and evaluated for their anticancer and antimicrobial activities. Objective: A series of new 2-(3,4-dimethoxyphenyl)-1H-benz(or pyrido)azoles were synthesized and evaluated for their anticancer and antimicrobial activities. Method: N-(5-chloro-2-hdroxyphenyl)-3,4-dimethoxybenzamide 1, was obtained by the amidation of 2-hydroxy-5-chloroaniline with 3,4-dimethoxybenzoic acid by using 1,1'-carbonyldiimidazole. Cyclization of 1 to benzoxazole derivative 2, was achieved by p-toluenesulfonic acid. O...

Neutropenia due to intensive chemotherapy in haematological malignancy patients leaves the host vulnerable and makes them susceptible to infections. Infections are the most important cause of morbidity and mortality especially in haematological malignancy and chemotherapy patients. In addition, the use of multiple or inappropriate antibiotics leads to the development of resistant microorganisms. Therefore, the choice of empirical treatment is of vital important in these patient groups. Escherichia coli, Acinetobacter baumannii and Klebsiella pneumoniae are among the most frequently isolated Gram negative bacteria in neutropenic patients. Rectal swab (RS) samples were obtained from haematological malignancy patients not yet on chemotherapy or have no infection on chemotherapy period, E. coli was isolated from these samples, and A. baumannii and K. pneumoniae colonization were investigated. Susceptibilities of bacteria against antibiotics used in empirical treatment and prophylaxis were determined by using Gradient test strips according to the EUCAST recommendation. All isolates were sensitive against colistin. The resistant rates of antibiotics were detected as 39.1%, 9.4%, 6.8%, 35.1%, 31%, 39.1% for ciprofloxacin, meropenem, imipenem, piperacillin-tazobactam, cefepime, ceftazidime respectively The clonal relationship between Gram negative bacteria of intestinal flora and infection agents of same patient was investigated by Pulsed-Field gel electrophoresis. Twenty-three of the 30 patients (76.6%) were found to have a clonal relationship between the bacterial isolates before and after infection. It was determined that it can be able to predict with RS samples about possible agents of infection and their antibiotic susceptibility patterns.

In recent years rapidly growing antibiotic resistance has increased interest toward natural products, especially essential oils because of their various effects. The aim of this study was to identify the chemical composition of the commercial Origanum onites essential oil (EO) and to investigate the antimicrobial activity by disc diffusion and dilution methods, against ten different ATCC strains, including eight bacteria, two yeasts and seventy-nine clinical nosocomial Escherichia coli isolates that produce extended spectrum beta lactamase (ESBL). The chemical composition of EO was analyzed by GC and GC-MS. The major compounds of the EO were determined as carvacrol (51.4%) followed by linalool (11.2%), p-cymene (8.9%) and γ-terpinene (6.7%). O. onites EO had antimicrobial activity against all standard strains and inhibited microbial growth of ESBL positive E. coli isolates. According to our results, O. onites EO may be an alternative to synthetic drug, used in combination with other...

This study applied two phenotypic tests, namely “Carbapenemase Nordmann–Poirel” (CarbaNP) test and “Carbapenem Inactivation Method” (CIM), against the isolates carrying the carbapenem resistance genes. The study included 83 carbapenem-resistant Enterobacteriaceae isolates producing oxacillinase-48 (OXA-48) and 30 carbapenem-sensitive Enterobacteriaceae isolates. Out of the total isolates studied, 77 isolates (92.77%) were identified as Klebsiella pneumoniae and six isolates (7.23%) were identified as Escherichia coli by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry. Polymerase chain reaction (PCR) method used to detect resistance genes found that 74 isolates (89.16%) produced OXA-48 carbapenemase, whereas nine isolates (10.84%) produced both OXA-48 and New Delhi metallo-beta-lactamase-1 (NDM-1). The isolates producing both OXA-48 and NDM-1 were found to be positive by both phenotypic tests. Among isolates carrying only blaOXA-48 gene alone, nine isolat...

The viridans group Streptococci (VGS) are most abundant in the mouth; in some instances they might emerge as pathogens particularly in infective endocarditis (IE). In this study, we aimed to define and determine the susceptibility against antibiotics of VGS that are members of the oral microbiota of patients exhibiting a risk of developing IE. Forty-nine patients at risk of infective endocarditis were included in the study. Identification of the bacteria was performed using API STREP (bioMérieux, France). Gradient test strips (E-Test, France) were used to determine MIC of the bacteria against penicillin, ampicillin, and vancomycin. The distribution of the isolated VGS groups was determined as follows: Streptococcus mitis 32.6% and anginosus group - 32.6%, S. sanguinis group - 16.3%, S. mutans group - 12.2%, and S. salivarius group - 6.1%. The rates of resistance and reduced sensitivity of the isolates for penicillin and ampicillin were determined at 61.2% and 55.1%, respectively. Ho...

Abstract Widespread existence of drug-resistant pathogens poses a threat to the successful treatment of bacterial diseases and increases the need for new antibacterial agents. Natural products are the basic source of antibacterial therapeutic agents for now, and will remain so in the future. Therefore, the aim of this study was to determine the antibacterial activity of cinnamon oil against carbapenem-resistant nosocomial isolates of Acinetobacter baumannii (111) and Pseudomonas aeruginosa (136). The essential oil composition of cinnamon oil was analyzed by GC, GC/MS and the antimicrobial effect of cinnamon oil was determined by disk diffusion method. The observed zone diameters were compared with carbapenem breakpoints (CLSI standard) and it was found that only one of the P. aeruginosa isolates was within resistance limits. Thus, cinnamon oil has antimicrobial activity with potential use as an antimicrobial agent in the pharmaceutical industry and an additive in the food industry.

Urinary tract infections (UTI) are among the most commonly encountered infections and are thus associated with widespread usage of antibiotics. Escherichia coli is the commonest bacteria isolated in UTI and treatment alternatives are limited in extended spectrum beta-lactamase (ESBL) producers. The aim of this study was to determine antibiotic susceptibility, ESBL production of the Escherichia coli strains and comparison of (ESBL) (+) and ESBL (-) strains, those were isolated in the Clinical Microbiology Laboratory, from urine samples of patients who presented to Ankara Dışkapı Yıldırım Beyazıt Training Hospital with urinary tract infections, in a period between January 2007 and June 2007. Conventional bacteriologic methods were used in identification and a total of 130 E.coli species were isolated. Sensitivity tests were performed according to the guidelines and criteria of National Committee for Clinical Laboratory Standards (NCCLS) using Kirby-Bauer disk diffusion method. The hig...