Yazar "Kus, Halit" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Genotype distribution of extended Spectrum beta-Lactamase producing Escherichia coli and Klebsiella pneumoniae.
    (ALLIED ACAD, 2015) Dagi, Hatice Turk; Al Dulaimi, Dhay Ali Azeez; Kus, Halit; Seyhan, Tuba; Findik, Duygu; Tuncer, Inci; Arslan, Ugur
    Extended-spectrum beta-lactamase (ESBL) production is the most important cause of beta-lactam resistance in Gram-negative bacteria. Although it may also be found in other Gram-negative bacteria, ESBL is most commonly produced by Escherichia coli and Klebsiella pneumoniae strains. In this study, we aimed to investigate the distribution of beta-lactamase genes in ESBL-producing E. coli and K. pneumoniae strains. One hundred and twenty isolates of E. coli and K. pneumoniae isolated from clinical samples were used in this study. The identification and the antibiotic susceptibility tests were performed by VITEK 2 system in accordance with the manufacturer's instructions. ESBL production was determined accoring to Clinical and Laboratory Standards Institute guidelines. The DNA isolation was performed with a commercial kit following company recommendations. (TEM)-T-bla, (SHV)-S-bla and (CTX)-C-bla-M genes were amplified by multiplex PCR with specific primers. Of the 120 isolates collected, 84 isolates were of E. coli and 36 isolates were of K. pneumoniae. (TEM)-T-bla gene was the most prevalent type (85.8%) followed by (CTX)-C-bla-M (83.3%) and (SHV)-S-bla (24.2%). No blaSHV gene was detected in the E. coli strains. Among 120 ESBL-producing strains, 10.8% were susceptible to cefepime, 10.0% to ceftazidime, while 5.0% to ceftriaxone. In conclusion, (TEM)-T-bla gene was the most frequently encountered ESBL of E. coli and K. pneumonia in our hospital. Further molecular surveillance and epidemiological studies of such resistant bacteria are recommended for monitoring and controlling the spread of ESBL producing strains.
  • Küçük Resim Yok
    Öğe
    In Vitro Synergistic Activity of Sulbactam in Combination with Imipenem, Meropenem and Cefoperazone Against Carbapenem-Resistant Acinetobacter baumannii Isolates
    (ANKARA MICROBIOLOGY SOC, 2014) Dagi, Hatice Turk; Kus, Halit; Arslan, Ugur; Tuncer, Inci
    Acinetobacter baumannii which is an opportunistic pathogen leading to nosocomial epidemics, exhibit high rates of antimicrobial resistance. Treatment of Acinetobacter infections is a challenge since most of the isolates are multiple antibiotic resistant. The aim of this study was to investigate minimum inhibitory concentrations (MICs) of sulbactam, imipenem, meropenem, and cefoperazone and in vitro synergistic activity of sulbactam in combination with imipenem, meropenem and cefoperazone against A.baumannii isolates of hospitalized patients. Forty A.baumannii strains isolated from various clinical specimens and found to be resistant to carbapenems by disc diffusion method, were included in the study. The isolates were identified by conventional methods and VITEK 2 (bioMerieux, France) automated identification system. MICs of sulbactam, imipenem, meropenem, and cefoperazone were determined by the broth nnicrodilution method according to the standards of CLS1 and in vitro synergy test was performed using the checkerboard microdilution method. Synergistic, partial synergistic, additive, indifferent and antagonistic effects of drug combinations were evaluated with the fractional inhibitory concentration index (FICI). Interpretation of the FICI was as follows: 0.5 synergy; <= 0.5 to < 1 partial synergy; 1 additive; > 1 to < 4 indifference; and >= 4 antagonism. Forty A.baumannii isolates were resistant to imipenem and cefoperazone, but two were susceptible, seven were moderately susceptible and 31 were resistant to meropenem with the microdilution method. MIC values of the isolates for sulbactam were found to be 4 mu g/ml in two, 8 mu g/ml in five, 16 mu\g/ml in three, 32 mu g/ml in 13, 64 pg/ml in three, 128 pg/ml in six and > 128 pg/ml in eight isolates. According to the FICI; imipenem/sulbactam combination exhibited synergy in 18 (45%), partial synergy in 4 (10%) and indifferent effect in 2 (5%) isolates, the combination of meropenem and sulbactam showed synergy in 19 (48%), partial synergy in 3 (7.5%), and indifferent effect in 3 (7.5%) isolates, the combination of cefoperazone/sulbactam demonstrated synergy in 18 (45%), partial synergy in 2 (5%), and indifferent effect in 2 (5%) isolates. There was no antagonistic effect with the tested combinations. In conclusion, MIC values of sulbactam were generally high in carbapenem-resistant A.baumannii strains. However, synergistic effect was detected in approximately half of the strains with the sulbactam/carbapenem combinations. The data obtained in this study should be supported by further advanced in vitro and clinical studies to predict the accurate clinical efficacy of sulbactam containing combinations on A.baumannii infections.
  • Küçük Resim Yok
    Öğe
    Investigation of Various Virulence Factors of Klebsiella pneumoniae strains Isolated from Nosocomial Infections
    (ANKARA MICROBIOLOGY SOC, 2017) Kus, Halit; Arslan, Ugur; Turk Dagi, Hatice; Findik, Duygu
    Klebsiella pneumoniae is an opportunistic pathogen that commonly affects immunosuppressed patients and causes nosocomial infections. K. pneumoniae has a variety of virulence factors, especially capsule polysaccharide, hypermucoviscosity (HV), fimbriae, toxins and determinants for iron acquisition. The aim of this study was to detect the virulence factors in K. pneumoniae strains isolated from nosocomial infections in two years. Fifty three K. pneumoniae strains isolated from the samples of patients with nosocomial infections in the Medical Microbiology Laboratory of Selcuk University Faculty of Medicine Hospital between 2011 and 2013 were included in the study. Identification and antimicrobial susceptibilities of the isolates were performed by VITEK 2 automatic system. Biofilm formation, alpha-hemolysin, capsule and HV were investigated by phenotypic methods. Polymerase chain reaction (PCR) was used to detect virulence genes encoding adhesins (fimH-1, mrkD, kpn, ycfM), siderophores (entB: enterobactin, iutA: aerobactin, irp-1, irp-2, ybtS, fyuA: yersiniabactin, iroN: catechols receptor), protectines or invasins (rmpA, magA, traT) and toxins (hlyA, cnf-1). Of the 53 K. pneumoniae isolates, 12 (22.6%) were isolated from in patients of reanimation intensive care unit, 8 (15.1%) medical oncology, 7 (13.2%) newborn intensive care unit and 26 (49%) other clinics. The distribution of the isolates according to the samples was as follows: urine (n=14), blood (n=13), wound (n=8), drainage fluid (n=10), broncho-alveolar lavage (n=7), and cerebrospinal fluid (n=1). Isolates which were resistant to meropenem were 5.7% and production of extended spectrum beta-lactamase (ESBL) was 71.7%. The capsule, biofilm formation, and HV were observed in 100%, 79.2%, and 1.9% of the isolates, respectively. Production of alpha-hemolysin was not detected in any of the isolates. The genes; entB (96.2%), ycfM (86.8%), and mrkD (83.0%) showed high prevalence. The other genes were detected in different ratios: fimH-1 (64.2%), fyuA (54.7%), kpn (49.1%), ybtS (41.5%), irp-1(41.5%), irp-2 (37.7%), traT (11.3%) and iutA (5.7%). Virulence genes; iroN, rmpA, magA, hlyA and cnf-1 were not detected in any of the isolates. Enterobactin had the highest rate among siderophores, and ycfM and mrkD in adhesins. The capsule and biofilm formation were commonly found in the isolates. Hypermucoviscosity was only found in one isolate but associated genes were not detected. Alfa hemolysin production and hlyA gene were not determined. As a result, it seems that the basis of the pathogenicity of K. pneumoniae strains isolated from nosocomial infections are capsule, adhesins, enterobactin and ability of biofilm formation. There is a need for new studies for the continuous monitoring of toxin and invasion ability as well as antibiotic resistance in the control of hospital infection caused by K. pneumoniae.