Browsing by Subject "bacterial virulence"

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    The role of virulent Helicobacter pylori strains in the etiopathogenesis of coronary artery disease; [Virulan Helicobacter pylori suslarinin koroner arter hastaligi etyopatogenezindeki rolu]
    (1999) Yuceyar H.; Saruc M.; Arslan S.; Goksel G.; Ozbakkaloglu B.; Uyanik B.S.; Yigitoglu R.; Sengil A.Z.
    Epidemiological studies have shown a positive correlation between coronary artery disease (CAD) and gastric Helicobacter pylori (H. pylori) infection. The possible mechanism by which H. pylori could increase the risk of CAD is chronic inflammation. More virulent H. pylori strains bearing the cytotoxin associated gene-A (CagA) can induce much more inflammation than CagA negative strains. The aim of our study was to assess the role of virulent H. pylori strains and inflammatory response in the pathogenesis of CAD. We studied 30 patients with CAD, age and sex being matched with 30 controls of similar social class. We determined the presence of H. pylori infection by rapid urease test, histology and serology (anti-H. pylori IgG). CagA status, serum tumor necrosis factor-alpha (TNF-α), gastrin and fibrinogen levels were also studied. The presence of H. pylori infection was statistically equal in CAD group (93.3%) and controls (86.6%)(p = 0.705). Serum CagA titers were 28.13 ± 9.21 U and 18.32 ± 5.8 U in the CAD and control group respectively. Serum TNF-α levels were 15.21 ± 4.30 pg/ml in the CAD group and 5.36 ± 2.41 pg/ml in the control group. Serum CagA and TNF-α levels showed a significant difference between the two groups (p = 0.000). Patients with CAD had a higher prevalence of CagA-positive strains than controls (67.8% versus 42.3%; p = 0.021). The serum gastrin level was higher in CAD but there was no significant difference between two groups (p = 0.379). Fibrinogen levels of the CAD group were significantly higher than those of the control (370 ± 51 mg/ml and 247 ± 43 mg/ml, p = 0.001). Further more, numbers of occluded vessels in CAD patients were positively correlated with both cagA positivity and TNF-α levels. In conclusion, CagA bearing strains of H. pylori may increase the risk of CAD by inducing chronic inflammation and increasing the expression of cytokines and procoagulant substance.
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    The effect of CagA status on response to Helicobacter pylori eradication therapy in Western Turkey
    (Associacao Brasileira de Divulgacao Cientifica, 2001) Saruç M.; Goksel G.; Ozkaya S.; Guclu F.; Ozbakkaloglu B.; Yuceyar H.
    If cytotoxin-associated gene A (CagA) status affects the response rates of therapy, then it may be possible to predict Helicobacter pylori eradication rates. We aimed to evaluate the response to eradication treatment of H. pylori infection in CagA-positive and CagA-negative patients. A total of 184 patients (93 males, 91 females, mean age 42.6 ± 12.8 years) with H. pylori-positive chronic gastritis were studied. Subjects underwent a gastroscopy and biopsy specimens were taken from the gastric antrum, body, and fundus. Before the eradication therapy was given all patients were tested for CagA, TNF-α and gastrin levels. They were then prescribed lansoprazole (30 mg bid), clarithromycin (500 mg bid), and amoxicillin (1.0 mg bid) for one week. On the 8th week a second endoscopy was performed and further biopsy specimens were obtained from the same sites as in the initial endoscopy. One hundred and twenty-seven patients (69.1%) were found to be CagA positive and 57 patients (30.9%) were CagA negative. The total eradication rate was 82.6%. In the CagA-positive group this rate was 87.4%, and in the CagA-negative group it was 71.9% (P = 0.019). TNF-α levels were higher in the CagA-positive than in the CagA-negative group (P = 0.001). However, gastrin levels were not different between groups (P = 0.421). Our findings revealed that CagA-negative status might be a risk factor for failure of H. pylori triple therapies. The CagA pathogenicity island gives a growth advantage to H. pylori strains and has been associated with an increase in the inflammatory response at the gastric mucosal level. These properties could make CagA-positive H. pylori strains more susceptible to antibiotics.
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    Investigation of Antimicrobial Resistance, Biofilm Production, Biofilm Associated Virulence Genes and Integron Genes of Pseudomonas aeroginosa Isolates Obtained from Animal Clinical Samples
    (Israel Veterinary Medical Association, 2022) Ocak F.; Turkyilmaz S.
    The results of antimicrobial treatment in Pseudomonas aeroginosa infections may depend not only on the antibiotic susceptibility of the etiologic agents, but also on the biofilm production and integron carrying capabilities of the bacteria. This study aimed to examine the relationship between antimicrobial resistance and biofilm production, biofilm related virulence genes, integron genes carried by P. aeroginosa isolates obtained from different animal clinical samples. A total of 67 P. aeroginosa isolates obtained from bovine mastitis, canine otitis and dermatitis cases were used as material. Bacterial identification was carried out using conventional methods. Qualitative (Congo Red Agar Test (CRA)) and quantitative (Microplate Test (MP)) methods were used to determine the phenotypic biofilm production capacity of the isolates. Polymerase chain reaction (PCR) was used to confirm the genus and species level identification of the isolates, and to identify biofilmassociated virulence genes and integron genes. The resistance patterns of the isolates against 12 antibiotics belonging to 6 antimicrobial families were examined using the disk diffusion method. Isolates resistant to at least three drug classes were defined as multi-drug resistant (MDR). The Chi-Square (χ2) test was used to compare the relationship between the MDR capacity of the isolates and biofilm formation, the prevalence of biofilm-associated virulence genes and the prevalence of integron genes. It was determined that 41.8% of the isolates as by qualitative method and 64.2% by the quantitative method were biofilm producers. The genes responsible for biofilm formation, ppyR, pslA and pelA, were detected in 94.0%, 83.6% and 65.7% of the isolates, respectively. 23.9% of the isolates carried the integron gene. Piperacillin tazobactam and ceftolozane tazobactam were found to be the most effective drugs against P. aeruginosa isolates studied. 28.4% of the isolates were MDR. As a result of this study, it was determined that MP was more effective than CRA in determining biofilm production phenotypically. While there was no significant relationship between MDR capacities with phenotypically biofilm formation, the prevalence of ppyR and pslA virulence genes, the relationship between the prevalence of pelA virulence gene and the presence of integron genes, was significant. © 2022, Israel Veterinary Medical Association. All rights reserved.
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    The Evaluation of the Diagnostic Performance of the BioFire FilmArray Meningitis/Encephalitis Panel in Children: A Retrospective Multicenter Study
    (Georg Thieme Verlag, 2022) Bal A.; Saz E.U.; Arslan S.Y.; Atik S.; Bayturan S.; Yurtseven A.; Gazi H.; Cicek C.; Kurugol Z.; Bal Z.S.
    Objective Acute bacterial meningitis (ABM) declined after implementing conjugate Haemophilus influenzae type B and the pneumococcal vaccines worldwide. However, it still contributes to significant morbidity and mortality. The Biofire FilmArray Meningitis Encephalitis (FAME) panel can rapidly diagnose common bacterial and viral pathogens. Several studies suggested that the use of FAME may accelerate diagnosis and decrease the time to pathogen-specific therapy. However, the clinical utility is still controversial due to scarce data and relatively high costs. Therefore, we aimed to evaluate the diagnostic performance of FAME in children. Methods A retrospective multicenter cross-sectional study was conducted to evaluate FAME in diagnosing ABM in children with a suspected central nervous system infection between January 2017 and May 2021. Results This study consisted of 179 children diagnosed with central nervous system infection who had parallel testing done using FAME and traditional microbiological diagnostic methods. Twenty-two FAME results were positive; 8 (36.3%) were bacterial pathogens and 14 (53.7%) were viral pathogens . The most common viral pathogen was human herpesvirus 6 (n = 6; 27.2%), followed by herpes simplex virus 1 (n = 4; 18.1%), Enterovirus spp. (n = 2; 9%), Parechovirus (n = 2; 9%), and Cytomegalovirus (n = 1; 4.5%). Bacterial pathogens included S. pneumoniae (n = 3; 13.6%), H. influenzae (n = 3; 13.6%), Neisseria meningitidis (n = 1; 4.5%), and Streptococcus agalactiae (n = 1; 4.5%). Bacterial culture confirmed S. pneumoniae infection in only 1 of 8 (12.5%) patients, while 7 of 8 bacterial meningitis were only detected by FAME. Conclusion FAME may also help with diagnosis and pathogen identification in patients who have already had antibiotics before cerebrospinal fluid collection. The use of FAME to detect infections quickly may minimize the improper use of medications, treatment duration, and the cost of hospitalization. © 2022. Thieme. All rights reserved.
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    Investigation of genetic relatedness, antimicrobial resistance, biofilm formation, biofilm-related virulence genes and integron-related genes of Stenotrophomonas maltophilia isolates obtained from bovine milk samples with mastitis
    (Hellenic Veterinary Medical Society, 2023) Ocak F.; Turkyilmaz S.
    Treatment of infections caused by the opportunistic pathogen Stenotrophomonas maltophilia is complicated by the bacterium’s ability to produce biofilms and high antibiotic resistance. This study aimed to investigate the prevalence of genetic relatedness, antimicrobial resistance, biofilm formation, biofilm-related genes with virulence and integron-related genes among isolates of S. maltophilia recovered from bovine milk with subclinical mastitis. In this study, bacterial identification was performed using conventional methods. The smeT gene-based Polymerase Chain Reaction (PCR) was used for bacterial identification. PCR was also used to detect virulence and integron-related genes, too. The quantitative Microplate Test (MP) method was used to determine the phenotypic biofilm production capacity of the isolates. The resistance patterns of the isolates against nine antibiotics belonging to nine antimicrobial families were examined using the disk diffusion method. Isolates resistant to at least three drug classes from various antimicrobial drug classes were defined as multi-drug resistant (MDR). The genetic linkage of S. maltophilia isolates was investigated by Enterobacterial Repetitive Intragenic Consensus (ERIC) PCR. Chi-square (χ2) test was used to reveal statistical difference between MDR and integron-related gene prevalances as well as biofilm formation capacity of isolates and biofilm-related virulence genes. In the study, a total of 312 milk samples with subclinical mastitis were taken from 27 farms. Ten isolates from five farms were phenotypically and genotypically identified as S. maltophilia. All isolates were resistant to cefepime and imipenem. 80% of the isolates carried at least one of the integron-related genes and 70% were MDR. The phenotypically biofilm-forming capacity identified in isolates was detected at 80%. The prevalence of the studied virulence genes was rpfF 60%, rmlA 70%, spgM and smf1 80%. There was no significant relationship between the biofilm-forming capacity of the isolates and the prevalence of biofilm-related virulence genes and MDR with integron-related genes. In the UPGMA analysis performed, a total of five genotypes were found, two single and three multiple according to 18% similarity coefficient. The presence of same isolates on the same farm and closely related isolates on different farms may suggest a clonal spread. ERIC-PCR can be useful in identifying S. maltophilia isolates with epidemic potential. S. maltophilia isolates were detected simply and quickly, using PCR based on the smeT gene, from bovine milk samples for the first time in Turkey. © 2023, F Ocak, S Turkyilmaz
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    Comparative study on genotypic properties of Pseudomonas aeruginosa isolated from subclinical mastitis in Türkiye
    (Hellenic Veterinary Medical Society, 2023) Ocak F.; Turkyilmaz S.
    The results of antibacterial treatment in mastitis may be related not only to the antibiotic sensitivity of the etiological factors but also to their abilities to carry integron and virulence genes. Integrons are mobile DNA elements that can capture and carry genes, particularly those responsible for antibiotic resistance. Pseudomonas aeruginosa has numberless virulence factors which are contributed to bacterial invasion and toxicity. This study aims to investigate antibiotic resistance, integron and virulence gene profiles of P. aeruginosa isolates obtained from cow milk with subclinical mastitis; further, was to evaluate the relationship between the antimicrobial resistance of bacteria with the integron and virulence gene carrying. The material of the study consists of 32 (9.8%) P. aeruginosa isolates obtained from 326 subclinical mastitis milk samples. After the bacterial identification by classical conventional methods, polymerase chain reaction (PCR) was carried out to confirm the genus and species of the isolates and to determine the integron and virulence gene profiles. Antimicrobial resistance was determined by the disk diffusion method using fifteen antibiotics belonging to eleven antimicrobial families. The relationship between the presence of integron and virulence genes associated with antibiotic resistance, further the relationship between the presence of virulence genes and antimicrobial resistance was calculated with the Chi-Square (χ2) test. Ten virulence genes (lasl, lasR, lasB, rhll, rhlR, rhlAB, plcH, plcN, ppyR, exoT) were found in all isolates whilst another virulence gene (aprA) was not present in any isolate. It was found that 34.4% of the isolates carried any integron gene. The results showed that the relationship is important between the presence of int genes and gentamicin, amikacin, tetracycline, cefoperazone, imipenem, aztreonam, ciprofloxacin, enrofloxacin resistance and exoU virulence gene presence. Also; there were also important associations between resistance to certain antibiotics and the presence of P. aeruginosa virulence genes. All isolates obtained in this study showed multiple antibiotic resistance (MDR). In these cases, showing the presence of integron and some virulence genes could play a prominent role in the resistance of P. aeruginosa isolates to antimicrobial drugs. This study may be important as it is the first study to show the presence of antibiotic resistance, integron and virulence genes together in subclinical mastitis cow’s milk isolates of P. aeruginosa in Türkiye. The presence of antibiotic-resistant P. aeruginosa strains in cattle farms may also pose a public health risk, as these bacteria can transmit their resistance genes to humans through food consumption © This work is licensed under a Creative Commons Attribution-NonCommercial 4.0.