Fetiye Kolayli

Characterization of ESBL (SHV-12) producing clinical isolate of Enterobacter aerogenes from a tertiary care hospital in Nigeria

BackgroundWe studied the beta-lactamases of an E. aerogenes isolate recovered from the blood of a two-year-old patient. The isolate demonstrated a disk-diffusion phenotype typical for an AmpC-ESBL co-producer.MethodsMicrobiology studies were performed according to standard protocols. The resistance gene was identified by transconjugation and cloning experiments.ResultsBy transconjugation only a narrow spectrum beta-lactamase (TEM-1) encoded on a small plasmid was transmitted. The ESBL was cloned and expressed in an E. coli host. Sequence analysis of the recombinant plasmid revealed blaSHV-12 associated to the insertion sequence, IS26.ConclusionThis is the first study demonstrated the occurrence of SHV-12 in Nigeria.

Outbreak of tularaemia in Golcuk, Turkey in 2005: Report of 5 cases and an overview of the literature from Turkey

Tularaemia was diagnosed by TaqMan RT-PCR and microagglutination tests in 5 patients, all from a new settlement constructed after the earthquake of 1999. During the follow-up, 129 more cases were found in this settlement (data from the local Health Care Authority). In this study, clinical features of 5 cases are presented briefly, and the Turkish literature on past outbreaks of tularaemia is reviewed.

Genetic and Enzymatic Properties of Metallo-β-Lactamase VIM-5 from a Clinical Isolate of Enterobacter cloacae

ABSTRACT A VIM-5-producing Enterobacter cloacae isolate (EDV/1) was identified in a collection of clinical strains stored before 2002. The gene, blaVIM-5, was located on a 2,712-bp BamHI-HindIII fragment of a 23-kbp (approximately) nonconjugative plasmid (pEDV5) in a class 1 integron as a single gene cassette.

Emergence and spread of carbapenem-resistant Acinetobacter baumannii in a tertiary care hospital in Turkey

An intensive care unit (ICU)-based OXA-23-producing multiple-drug resistant Acinetobacter baumannii (MDRAB) outbreak was detected between October 2005 and October 2006. A total of 47 patients were infected/colonized with the outbreak strain. Clinical data were available from 37 patients. The all-cause mortality rate among the patients exposed to the epidemic strain was 35% (13/37). The outbreak strain and the resistance determinants were characterized both by microbiological methods and by molecular techniques. Cloning and sequencing experiments identified ISAbaI-associated bla(oxa-23) on the chromosome. Screening of imipenem-resistant Acinetobacter isolated from the ICU during the outbreak period with PCR identified 97 isolates as positive for the ISAbaI-bla(oxa-23) structure. Pulsed-field gel electrophoresis and plasmid analyses with selected nonrepetitive isolates revealed the clonality. Disk diffusion on cloxacillin-supplemented agar media and the real-time PCR experiments showed that outbreak isolates are overexpressing the ampC enzyme. This study highlights the occurrence of OXA-23-producing and ampC-overexpressing MDRAB in ICUs.

Investigation of antibiotic resistance profile and TEM-type β-lactamase gene carriage of ampicillin-resistantEscherichia coli strains isolated from drinking water

Fifty-five ampicillin-resistant (Ampr)Escherichia coli strains were isolated from 51 drinking water points in Rize region containing abundant fresh water sources in Turkey during the years 2000 to 2002 and from January to February 2004. The large number of organisms (nearly 57%) exhibited resistance to three or more antibiotics commonly used in human and veterinary medicine. These strains displayed a multiresistant phenotype. Nearly half of the strains (27%) expressed resistance to ceftazidime, but these strains were not an extended-spectrum β-lactamase-producer according to the results of double-disk synergy test. All isolates were then screened for the carriage of TEM-type β-lactamase gene (blaTEM) by polymerase chain reaction. TEM-type β-lactamase genes were found in six (11%) isolates. Sequence analysis showed TEM-1 type genes. However, isoelectric focusing analysis did not confirm the production of TEM-1 type β-lactamase except for one strain. Conjugation experiments showed that resistance to ampicillin, tetracycline or trimethoprim/sulfamethoxazole was transferable in six (11%) isolates. Emergence of transferable antibiotic resistance andblaTEM-1 gene inE. coli strains from public drinking waters possesses a significant public health risk.

A novel application of Fourier-transformed infrared spectroscopy: classification of slime from staphylococci.

Abstract It has been proposed that the virulence of nosocomial Staphylococcus infections associated with indwelling medical devices is related to the ability of the bacterium to colonise these materials by forming a biofilm composed of multilayered cell clusters embedded in a slime matrix. However, the pathogenic role of exopolysaccharide biofilms is not fully understood. A new method was sought for differentiating the structure of slime from two closely related bacterial strains, Staphylococcus aureus and Staphylococcus epidermidis. Using PCR it was confirmed that these strains were positive for the icaA and icaD genes and the complete ica operon (2.7 kb). Monosaccharide analysis by thin-layer chromatography revealed an identical profile for both strains, with xylose and glucose present among the four visible bands. Using Fourier-transformed infrared spectroscopy and hierarchical cluster analysis, three of four S. aureus samples (75%), and four of five S. epidermidis samples were grouped according to species. A novel FTIR approach in classifying slime produced by S. aureus and S. epidermidis is reported.

OXA-162, a novel variant of OXA-48 displays extended hydrolytic activity towards imipenem, meropenem and doripenem

Context: Isolation and characterization of OXA-162, a novel variant of OXA-48. Objectives: Klebsiella pneumoniae isolate with decreased susceptibility to carbapenems was recovered from a Turkish patient. This study aimed at characterizing the carbapenem resistance determinants of this isolate. Materials and methods: Antibiotic susceptibility tests, analytic isoelectric focusing (IEF), cloning and sequencing were performed. Cloned β-lactamase was purified by means of preparative gel electrophoresis and the kinetic constants were determined under initial rate conditions. Results: The identified blaOXA-162 gene was located on a ca. 45-kb plasmid carrying a transposon consisted of two IS1999-2 elements. OXA-162 differed from OXA-48 by a single amino acid substitution (Thr213Ala) which increased the catalytic efficiency (kcat/KM) of OXA-162 towards imipenem and meropenem. Also this substitution caused a gain of hydrolysis ability towards doripenem. Analysis of OXA-162 model implied that the amino acid change might generate an extension in the opening of the substrate entry site and might cause extended hydrolytic activity towards imipenem, meropenem and doripenem. Discussion and conclusion: OXA-162, a derivative of OXA-48 has enhanced catalytic properties.

Community-acquired CTX-M-15-type ESBL-producing Escherichia coli meningitis: a case report and literature review.

In this report, a case of community-acquired acute bacterial meningitis (CA-ABM) caused by CTX-M-15-producing Escherichia coli in an elderly male patient was presented in the light of literature. Cultures of cerebrospinal fluid, blood, ear discharge, and stool samples yielded CTX-M-15-producing E. coli in-vitro, which was resistant to the extended-spectrum cephalosporins and ciprofloxacin and susceptible to imipenem, meropenem and amikacin. Meningitis was treated with parenteral meropenem plus parenteral and intraventricular amikacin administration. Since bacterial meningitis is a life-threatening infection, empiric antibiotic therapy with carbapenem can be started before the culture results are obtained, mainly in areas where the ESBL epidemiology is well known.

In vitro antibacterial activity of various adhesive materials against oral streptococci

ABSTRACT The purpose of this study was to investigate the antibacterial activity of various adhesive materials against five different oral streptococci. The antibacterial activity of the adhesive systems was evaluated using agar diffusion tests. In each section of each plate, 6-mm-diameter wells were created with sterilized glass cylinders. Ten microlitres of self-etch adhesives and control materials were applied into the shallow holes. After incubation at 37 °C for 24 h, the growth inhibition zones were measured in millimetres. Statistical analyses were performed by using two-way analysis of variance and the Tukeys multiple range test (p < 0.05). A statistically significant difference was found between inhibition zones of oral streptococci cultivated with different adhesive systems (p < 0.01). Clearfil Protect Bond exhibited larger inhibition zones than the other materials that were used against the oral streptococci. The antibacterial effects observed for the different tested adhesive systems may be related to 12-methacryloyloxy dodecyl-pyridinium bromide and the acidic nature of the materials.

Production and mechanical properties of Ti–5Al–2.5Fe–xCu alloys for biomedical applications

In this study, the mechanical, antibacterial properties and cell toxicity response of Ti-5Al2.5Fe alloy with different copper contents were investigated. The alloys were prepared by high-energy ball milling using elemental Ti, Al, Fe, and Cu powders and consolidated by a uniaxial vacuum hot press. Staphylococcus aureus strain ATCC 29213 and Escherichia coli strain ATCC 25922 were used to determine the antibacterial properties of the sintered alloys. The in vitro cytotoxicity of the samples was evaluated with HeLa (ATTC, CCL-2) cells using thiazolyl blue tetrazolium bromide. The mechanical behavior of the samples was determined as a function of hardness and bending tests and analyzed by scanning electron microscopy, energy dispersive x-ray spectroscopy, optical microscopy and x-ray diffraction (XRD). The results showed that the Cu content significantly improved the antibacterial properties. Cu addition prevented the formation of E. coli and S. aureus colonies on the surface of the samples. All samples exhibited very good cell biocompatibility. The alloys with different copper contents showed different mechanical properties, and the results were correlated by microstructural and XRD analyses in detail. Our results showed that Cu has a great effect on the Ti5Al2.5Fe alloy and the alloy is suitable for biomedical applications with enhanced antibacterial activity.