Asiye Karakullukcu

Rapid and accurate diagnosis of healthcare-associated infections (HAIs) is an unmet need for improving outcomes in intensive care units (ICUs). Traditional culture-based methods, while the gold standard, are time-consuming and can delay therapeutic interventions. In this study, we evaluated the diagnostic utility of pathogen-specific immunoglobulin G (IgG) binding levels using an enzyme-linked immunosorbent assay (ELISA). We measured IgG binding against pathogens including Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Enterococcus faecium, and Staphylococcus aureus. Diagnostic performance was evaluated through receiver operating characteristic (ROC) curve analysis, with culture results as the reference. The assay demonstrated an overall diagnostic accuracy of 83.2%, with a sensitivity of 85.4%, a specificity of 81.4%, and an area under the curve (AUC) of 0.910. Pathogen-specific cutoff values ranged from 0.918 to 1.534. Especially, A. baumannii showed the highest performance metrics, achieving a sensitivity of 94.7%, a specificity of 93.6%, and an AUC of 0.975. The pathogen-specific IgG binding levels can offer a novel and effective diagnostic tool for the initial assessment of HAIs, enhancing early detection and improving patient management across healthcare settings.

Objective: Antimicrobial resistance is one of the most mportant health problems of recent years. Multidrug-resistant Klebsiella pneumoniae strains have been causing serious problems in many countries including Turkey in recent years. Aim of this study was to detect molecular mechanisms behind the carbapenem resistance in carbapenem-resistant K. pneurnoniae strains isolated from rectal swab samples and investigate the susceptibility of two potentially alternative drugs, fosfornycin, and chloramphenicol. Methods: 46 K. pneumoniae strains isolated from rectal screening cultures of intensive care unit patients by using MacConkey agar containing 2 mg/L meropenem were included in this study. Carbapenem resistance of strains were confirmed by minimum inhibitor concentrations of meropenem obtained with gradient strip test. Presence of the bla(KPC,) bla(NDM) and bla(OXA), bla(IMP) and bla(VIM) genes were investigated by the real-time polymerase chain reaction. Broth microdilution method was used to investigate chloramphenicol susceptibility, and gradient strip test was used to investigate fosfomycin susceptibility of the strains. Results: At least one carbapenemase gene was detected in all K. pneumoniae strains. While all strains were found positive for the presence of OXA-48 type carbapenemase gene, 12 (26%) out of 46 were positive for both OXA-48 and NDM-1 carbapenemase genes, and only one (2%) strain was positive for OXA-48, NDM-1, and IMP-1 carbapenemase genes. Only 3 (6%) out of 46 strains were found susceptible to fosfomycin while 23 (50%) of them were susceptible to chloramphenicol. Additionally, we observed that the resistance rates to fosfomycin and chloamphenicol tended to be higher among carbapenemase producers. Conclusions: It is estimated that fosfomycin is not going to be a good option for the treatment of infections caused by carbapenemresistant K. pneumoniae strains in Turkey since only 6% of them were susceptible. Although the chloramphenicol susceptibility rate (50%) was higher than fosfomycin, further clinical studies are required to provide a better knowledge about the usage of this antibiotic in systemic infections. Moreover, multiple carbapenemase producers tended to be more resistant to fosfomycin and also chloramphenicol.

The amounts of Akkermansia muciniphila and Faecalibacterium prausnitzii in gut microbiota are reduced in patients with allergic diseases compared to healthy controls. We aimed to quantify levels of A. muciniphila and F. prausnitzii amounts using real-time quantitative PCR (qPCR) in the gut microbiota of children with allergic asthma and in healthy controls. In total, 92 children between the ages of three and eight who were diagnosed with asthma and 88 healthy children were included in the study and bacterial DNA was isolated from the stool samples using the stool DNA isolation Kit. qPCR assays were studied with the microbial DNA qPCR Kit for A. muciniphila and microbial DNA qPCR Kit for F. prausnitzii. Both bacterial species showed a reduction in the patient group compared to healthy controls. A. muciniphila and F. prausnitzii were found to be 5.45±0.004, 6.74±0.01 and 5.71±0.002, 7.28±0.009 in the stool samples of the asthma and healthy control groups, respectively. F. prausnitzii and A. muciniphila may have induced anti-inflammatory cytokine IL-10 and prevented the secretion of pro-inflammatory cytokines like IL-12. These findings suggest that A. muciniphila and F. prausnitzii may suppress inflammation through its secreted metabolites.

Tick-borne encephalitis virus (TBEV) and West Nile virus (WNV) are mainly transmitted by arthropod vectors to vertebrate hosts including humans, resulting in fever and neurological signs. The aim of this study was to investigate the presence of antibodies to TBEV and WNV, and TBEV-RNA and WNV-RNA in Turkish children with fever and/or arthritis. For this purpose, 110 sera and buffy-coat samples were collected; sera were analyzed by indirect enzyme-linked immunosorbent assay for the presence of IgM and IgG antibodies to TBEV and WNV, and buffy-coat-derived white blood cells were analyzed by quantitative real-time RT-PCR for TBEV-RNA and WNV-RNA. IgM antibodies to TBEV were detected in five children between the ages of 3 and 7 years; no IgG antibodies to TBEV were detected. IgG antibodies to WNV were detected in two children and IgM antibodies to WNV were detected in six children, between the ages of 3 and 7 years. One of the children had IgM antibodies to WNV and to TBEV. Children who had antibodies to TBEV and WNV had fever and/or arthritis but no obvious neurological signs. Molecular diagnostic approaches revealed that neither TBEV-RNA nor WNV-RNA was present in any of the buffy-coat samples, not even in children with IgM-specific antibodies. Our serological results indicate that children in Turkey are exposed to TBEV and WNV.

Vancomycin-resistant Enterococci (VRE) cause outbreaks and infections by easily spreading in hospitals. Effective cleaning and disinfection play an important role to control and prevent VRE infections. We aim to investigate the clinical and in vitro efficacy of a nanotechnology-based surface disinfectant on VRE contamination and colonization.

Carbapenem resistance, Enterobacteriaceae, rectal swab, isepamicin, chloramphenicol.