Asiye Karakullukcu

Determination of clinical significance of coagulase-negative staphylococci in blood cultures

The aim of this study was to investigate the criteria used to distinguish coagulase-negative staphylococci (CoNS) bacteremia from contamination. We evaluated 162 adult patients with CoNS-positive blood cultures (BCs). Of the 162 patients, 35 (21.6%) had at least 2 positive BCs and 127 (78.4%) had a single positive BC. According to the Laboratory-Confirmed Bloodstream Infection (LCBI) criteria, 24 (14.8%) patients with the same species of CoNS had true bacteremia, and 138 (85.2%) patients had contaminants. Despite the detection of the same CoNS species, 9 of the 24 patients had different CoNS genotypes. Using clinical assessments, only 20 patients were diagnosed with true bacteremia, 8 of them had a single positive BC. We concluded that only using the LCBI criteria or clinical evaluations of a patient were not sufficient to distinguish CoNS bacteremia from contamination. Molecular identification should also be performed as a diagnostic laboratory parameter for CoNS bacteremia.

Patterns of EPIYA motifs among cagA-positive Helicobacter pylori strains: a case–control study in a Turkish population with Eurasian geographical features

Geographical variation in the frequency of various gastroduodenal pathologies was shown to be related to the geographical diversity of H. pylori CagA Glu-Pro-Ile-Tyr-Ala (EPIYA) patterns. We examined the EPIYA patterns of H. pylori and the association of EPIYA patterns with gastric cancer (GC) for the first time, to the best of our knowledge, in Turkey. The patient group (PG) contained 60 patients [38 GC and 22 duodenal ulcer (DU) patients]. The control group (CG) was 110 individuals [94 gastritis patients and 16 persons with a normal gastrointestinal system (NGIS)]. Specific primers were used for the detection of cagA including empty-site-positive and EPIYA-A, -B, -C, -D PCR. Bands of EPIYA-A, -B, -C were confirmed by DNA sequencing. One hundred and forty-two (83.5 %) strains [60 in the PG (38 GC, 22 DU), 82 in the CG (72 gastritis, 10 NGIS)] were positive for the cagA gene. EPIYA-C with multiple repeats was detected in 34 (23.9 %) strains, and 22 (64.7 %) were from GC patients. EPIYA-C with one repeat was detected in 89 (62.7 %) strains, and 54 (60.7 %) were from gastritis patients. EPIYT was detected in 10 strains, and EPIYA-D was not detected. The number of EPIYA-C with multiple repeats was significantly higher for the PG than for the CG (P < 0.0001). In GC patients, the number of EPIYA-C with multiple repeats was significantly higher than one repeat (P < 0.0001). In conclusion, our study showed that multiple EPIYA-C repeats increases the GC risk by 30.6-fold and the DU risk by 8.9-fold versus the CG. This indicates that Western-type H. pylori strains in Turkey have similar EPIYA motifs to those of neighbouring countries and Western populations.

The protective role of Helicobacter pylori neutrophil-activating protein in childhood asthma

BACKGROUND Helicobacter pylori quantity and HP-NAP gene expression were evaluated in the faeces of healthy and asthmatic children. METHODS H. pylori DNAs and RNAs were isolated from the stool samples of 92 asthmatic children (AC; 3-8 years) and 88 healthy controls (HC). Quantitative PCR was used to determine the quantity of H. pylori and HP-NAP expression relative to the 16S rRNA (reference gene). Gene expression was analysed using the delta delta-Ct method. RESULTS H. pylori DNA was detected in the stool samples of 18 (20.4%) of the 88 HC (p<0.0001, OR=0.79) and none of AC. No meaningful statistical differences were found between individuals with positive and negative family histories for asthma in AC and HC (p>0.05). H. pylori quantity was higher in seven of 18 H. pylori-positive samples, but HP-NAP expression levels were low in four of these seven samples. Based on a multivariate logistic regression analysis of these three variables together, only males displayed a significant difference based on gender differences (p<0.02) and it was determined that, based on the OR value of 0.46 and the 95% CI range of 0.241-0.888, male gender was an independent protective factor in asthma. CONCLUSIONS HP-NAP levels vary to the relative concentrations of bacteria in the stationary or late logarithmic phases. Different napA expression levels may be caused by different endogenous napA gene expression or different environmental conditions.

Neopterin and soluble CD14 levels as indicators of immune activation in cases with low anti-HCV reactivity and true HCV infection

Neopterin and soluble CD14 (sCD14) are detected at high levels in hepatitis C virus (HCV) infections. We aimed to evaluate the role of these plasma immune activation biomarkers, for the indirect assessment of immune activation status of patients with low anti-HCV reactivity and a HCV infection. Low anti-HCV reactivity group (LRG, n: 70), true positive HCV infection group (THG, 30) and healthy control group (HCG, 30) were analyzed in this study. We have used ELISA, HCV RIBA/LIA and HCV-RNA methods. Mean neopterin levels were significantly lower in LRG than THG (p <0.001). In contrast, those values were not significantly different from those of HCG (p >0.05). Mean sCD14 were significantly higher in LRG than THG and HCG (p <0.05, p <0.001). Values of 3.95 μg/ml and 5.36 nmol/l for sCD14 and neopterin resulted in the maximum area under the receiver operating characteristic curves (ROC), which were 0.859 (95% CI, 0.745 to 0.935; <0.0001) and 0.788 (95% CI, 0.663 to 0.883; <0.0001), respectively. These cut-offs corresponded to a sensitivity of 73.3% and a specificity of 73.3% for neopterin and of 100% and 76.7% for sCD14. Our results suggest that a specific immunoactivation might be caused by true positive HCV infection. Due to the significant results sCD14 in LRG might be non-specifically affected by some underlying atypical immunohematological pathologies. Only neopterin might be used to exclude low anti-HCV reactivity from a true HCV infection. The use of neopterin but not sCD14 in combination with fourth-generation EIA/CMIA combo tests will be useful when nucleic acid tests are not available for screening blood donors at blood banks.