Bekir Çelebi

Seroprevalence of Neospora caninum in dairy cattle ranches with high abortion rate: special emphasis to serologic co-existence with Toxoplasma gondii, Brucella abortus and Listeria monocytogenes.

The aim of this study was to determine seroprevalence of Neospora caninum in dairy cattle ranches with higher abortion rates and co-existence of Neospora caninum, Toxoplasma gondii, Brucella abortus, and Listeria monocytogenes antibodies. The blood samples were collected from dairy cows with history of abortion (n=234) as well as from pregnant cows that were (n=323) kept in the same ranches. N. caninum seroprevalence was 10.77% (60/557). The co-existence rate of N. caninum seropositivity with T. gondii, B. abortus and L. monocytogenes was 24.77% (138/557), 13.82% (77/557) and 42.85% (162/378), respectively. Only one animal had significant antibody titers for all analyzed infectious agents. The seroprevalence of N. caninum and T. gondii were significantly higher in pregnant cows than aborted cows (p<0.05 and p<0.001, respectively). As a result, the comprehensive data generated through this study can significantly contribute to understanding of serologic association of N. caninum with T. gondii, B. abortus and L. monocytogenes in pregnant and aborted dairy cows.

Antimicrobial susceptibilities of Francisella tularensis subsp. holarctica strains isolated from humans in the Central Anatolia region of Turkey

OBJECTIVES To assess the in vitro susceptibility of Francisella tularensis subsp. holarctica biovar II strains to 24 antimicrobial agents. METHODS Thirty-nine F. tularensis strains isolated from humans in the Central Anatolia region of Turkey were examined. Each isolate was identified by conventional and molecular techniques. MICs of aminoglycosides, tetracyclines, fluoroquinolones, macrolides, penicillins, cephalosporins, imipenem, clindamycin, linezolid, chloramphenicol and rifampicin were determined using the Etest method on glucose/cysteine blood agar plates. Interpretation of results was made according to CLSI clinical breakpoints. RESULTS All strains were susceptible to aminoglycosides, tetracyclines, chloramphenicol, rifampicin and three fluoroquinolones. In contrast, resistance to penicillins, cephalosporins, carbapenems, macrolides and clindamycin was observed for all isolates. Fluoroquinolones had the lowest MIC(50) and MIC(90). CONCLUSIONS All strains were susceptible to the antibiotics traditionally used to treat tularaemia, such as streptomycin (MIC(90) 1.5 mg/L), gentamicin (MIC(90) 0.25 mg/L), tetracycline (MIC(90) 0.38 mg/L) and chloramphenicol (MIC(90) 0.25 mg/L). Since fluoroquinolones showed the lowest MIC values, and have important advantages over aminoglycosides, including ease of oral administration and lower toxicities, quinolones have the potential for being effective first-line therapy for tularaemia.

In vitro susceptibility of isolates of Francisella tularensis from Turkey.

Abstract Background: Tularemia is an infection caused by Francisella tularensis, which has a wide distribution in the northern hemisphere and diverse clinical manifestations. For decades, the drug of choice for the treatment of tularemia has been streptomycin, with tetracycline and chloramphenicol being used as alternatives. The purpose of the present study was to determine the in vitro antimicrobial susceptibility of a large panel of geographically diverse F. tularensis isolates from Turkey against traditional and newer antimicrobial agents. Methods: The antibiotic susceptibilities of 250 F. tularensis strains were examined using the Epsilometer test for 9 antimicrobial agents. Each isolate was identified by conventional and molecular techniques. Results: All the strains were confirmed biochemically and using a combination of species- and subspecies-specific polymerase chain reaction (PCR) assays to be F. tularensis subsp. holarctica. One isolate was assigned to F. tularensis subsp. holarctica biovar japonica based on erythromycin susceptibility, an ability to ferment glycerol, and the nucleotide sequence of the region of difference 1 (RD1). All strains were susceptible to aminoglycosides (streptomycin and gentamicin), tetracyclines (tetracycline and doxycycline), chloramphenicol, 2 fluoroquinolones (ciprofloxacin and levofloxacin), and rifampicin. In addition, all isolates except 1 had a minimal inhibitory concentration (MIC) for erythromycin of > 256 μg/ml. Conclusions: Since the fluoroquinolones showed the lowest MIC values and have advantages such as excellent bioavailability and activity, availability of oral formulations, and lower toxicities, they represent candidate therapeutic options in the first-line treatment of tularemia. To the best of our knowledge, this is the first report of the presence of F. tularensis subsp. holarctica biovar japonica outside Japan.

Evaluation of a commercial immunochromatographic assay for the serologic diagnosis of tularemia.

Tularemia is an infection caused by Francisella tularensis with a worldwide distribution in the northern hemisphere and diverse clinical manifestations. Serology plays an important role in the diagnosis of tularemia. A commercially available immunochromatographic assay (ICA) for the serologic diagnosis of tularemia (VIRapid Tularemia, Vircell, Granada, Spain) was evaluated, and the performance was compared with that of the current standard, the microagglutination test (MA). A panel of 221 sera from 109 cases of tularemia was tested as well as 236 sera from normal individuals or individuals with other infectious or autoimmune diseases. The ICA demonstrated 91.5% (κ = 0.91) agreement with the reference method (MA) and gave an overall sensitivity of 99.3% and a specificity of 94.6%. No cross-reactivity was observed in the ICA with serum samples from normal individuals and patients with autoimmune diseases and bacterial, viral, and parasitic infections, although 4 of 50 patients with brucellosis demonstrated positive results in the ICA. The performance of ICA was simple, and it requires no specialized equipment. The ease of use and significantly high sensitivity and specificity of ICA make it a good choice for diagnostic testing and a valuable field test to support a presumptive diagnosis of tularemia in remote areas.

Water as Source of Francisella tularensis Infection in Humans, Turkey.

Francisella tularensis DNA extractions and isolates from the environment and humans were genetically characterized to elucidate environmental sources that cause human tularemia in Turkey. Extensive genetic diversity consistent with genotypes from human outbreaks was identified in environmental samples and confirmed water as a source of human tularemia in Turkey.

Oxidative stress and tryptophan degradation pattern of acute Toxoplasma gondii infection in mice.

Toxoplasma gondii is a very common obligate single-cell protozoan parasite which induces overproduction of interferon (IFN)-gamma and of other proinflammatory cytokines. Although immunomodulatory role of IFN-gamma favors tryptophan (Trp) degradation via indoleamine-2,3-dioxygenase (IDO) activity and is related with nitric oxide (NO) synthesis, the mechanism of antitoxoplasma activity is complex. In order to characterize the Trp degradation pattern during the acute T. gondii infection, serum Trp, kynurenine (Kyn), and urinary biopterin levels of mice were measured. The possible oxidative status was evaluated by the liver, spleen, brain, and serum malondialdehyde (MDA) and NO levels. Increased free radical toxicity may cause elevation in tissue MDA in T. gondii-infected mice, while unchanged serum MDA might indicate the increased oxidative stress due to T. gondii infection restricted to intracellular area. Elevated serum NO most probably might be due to the formation of reactive nitrogen radicals. The Kyn/Trp ratio was higher in T. gondii-infected mice compared to healthy animals (p < 0.05); however, it was not correlated with urinary biopterin. These results suggested that Trp degradation might be promoted by a pathway other than IDO during T. gondii infection and the reduction of Trp concentration favors the local immunosuppression and systemic tolerance.

Investigation of anti-Toxoplasma gondii antibodies in cats of the Ankara region of Turkey Using the Sabin-Feldman dye test and an indirect fluorescent antibody test.

Blood samples from 99 cats from the Ankara province of Turkey were examined for the presence of anti–Toxoplasma gondii antibody with the use of both the Sabin–Feldman dye test (DT) and an indirect fluorescent antibody test (IFAT). Forty of the 99 sera (40.3%) were positive for antibodies against T. gondii with the DT, whereas the IFAT assay detected antibodies in 34 (34.3%). The study also evaluated 3 factors for their potential association with the presence of T. gondii antibody: age (<1 yr, 1–2 yr, and >2 yr), gender (female vs. male), and outdoor access (stray, owned with outdoor access, or indoor only). The DT detected antibodies in 3 cats under 1 yr of age, 22 cats between 1 and 2 yr, and 15 cats older than 2 yr, whereas the IFAT found 1, 18, and 15 cats positive for antibodies, respectively, in each of these categories. Of 61 female cats, 27 (44.2%) were positive by the DT; and of 38 male cats, 13 (34%) were positive by the DT. For the IFAT, 24 female cats (39.3%) and 10 male cats (26.3%) were positive. The percent seropositivity in indoor cats was 30.8% by the DT and 23.1% by the IFAT. In stray cats, the percent seropositivity was 52.8% by the DT and 41.7% by the IFAT. Antibody presence was significantly associated with age, but not with outdoor access.

Dobrava-Belgrade Virus in Apodemus flavicollis and A. uralensis Mice, Turkey

In 2009, human Dobrava-Belgrade virus (DOBV) infections were reported on the Black Sea coast of Turkey. Serologic and molecular studies of potential rodent reservoirs demonstrated DOBV infections in Apodemus flavicollis and A. uralensis mice. Phylogenetic analysis of DOBV strains showed their similarity to A. flavicollis mice–borne DOBV in Greece, Slovenia, and Slovakia.

Oropharyngeal Tularemia Outbreak Associated with Drinking Contaminated Tap Water, Turkey, July-September 2013

In 2013, an oropharyngeal tularemia outbreak in Turkey affected 55 persons. Drinking tap water during the likely exposure period was significantly associated with illness (attack rate 27% vs. 11% among non–tap water drinkers). Findings showed the tap water source had been contaminated by surface water, and the chlorination device malfunctioned.

Cytokine profile in murine toxoplasmosis.

OBJECTIVE To investigate which cytokines are produced after acute infection of mice with Toxoplasma gondii (T. Gondii) RH strain. METHODS Mus domesticus domesticus mice in infected group were inoculated with with highly virulent T. Gondii RH strain by intraperitoneally. Serum samples were obtained from infected and non-infected mice for cytokine levels for ELISA assay. RESULTS The concentrations of tumor necrosis factor-α, interferon-γ, interleukin (IL)-10 and IL-12 in the cardiac blood sample of the infected mice were significantly higher than those in uninfected controls (P<0.05). The levels of transforming growth factor-1β decreased in mice infected with T. gondii compared to those of the controls, the decrease was statistically significant (P<0.05). No significant difference was observed in levels of IL-4 between infected and healty control groups (P>0.05). CONCLUSIONS According to our findings, immune response into T helper type 1 was predominant during acute T. gondii infection. Further characterization and purification of Toxoplasma molecule(s) implicated in the regulation of cytokines could lead to the development of new drug prospects to control Toxoplasma infection.