Yusuf Yakupogullari

Background/Objectives: A reactive anti-HCV antibody result requires confirmatory testing because seropositivity does not necessarily indicate active hepatitis C virus (HCV) infection. Although anti-HCV signal intensity may provide clinically useful information, it remains underutilized, particularly in low-reactivity ranges where diagnostic uncertainty is substantial. This study evaluated the diagnostic performance of anti-HCV signal-to-cutoff (S/Co) values and aimed to define a clinically meaningful uncertainty interval. Methods: In this retrospective study, 565,726 anti-HCV test results were screened, and the analysis was performed within the anti-HCV reactive cohort (≥1.0 S/Co; n = 2950), comprising 1581 patients with true HCV infection and 1369 without infection. Infection status was assigned using a uniform virological reference standard, every case being supported by at least one documented positive HCV-RNA PCR result. Receiver operating characteristic (ROC) analysis was used to assess discrimination, and multivariable logistic regression to model the probability of true infection. Results: Anti-HCV signal intensity discriminated true infection well across the reactive cohort (AUC 0.991), but less within the diagnostic uncertainty interval (1.00–4.99 S/Co; AUC 0.832), where only 5.7% of reactive results represented true infection. A Youden-optimal threshold of 4.65 S/Co provided >95% sensitivity, specificity and positive predictive value in the reactive cohort. The probability of true infection rose steeply with signal level, and each doubling of the S/Co value increased the odds of infection 23–fold. No threshold within the uncertainty interval raised the positive predictive value above 58.2%. Restricting confirmatory testing to values above 2.50 S/Co would avoid 41.7% of confirmatory tests while missing 1.96% of true infections. Conclusions: Anti-HCV signal intensity is strongly associated with the probability of true infection, but a single fixed cut-off is insufficient for clinical interpretation. Graded, signal-based interpretation may improve diagnostic accuracy, clarify low-level reactivity, and reduce unnecessary confirmatory testing.

To determine the frequency of microbial DNA detection in patients with sterile pyuria and evaluate the association of leukocyte count and leukocyte esterase (LE) test results with physicians' treatment decisions. This prospective cross-sectional study was conducted over two months in the microbiology laboratories of two university hospitals. Urine samples from 201 patients with sterile pyuria (≥ 10 leukocytes/ml and/or LE positivity with negative urine culture) and 180 controls (no growth in culture and no pyuria) were analyzed. Multiplex PCR targeting 14 potential pathogens was performed. Demographic data, PCR results, and physicians' treatment decisions were recorded. Chi-square tests and logistic regression assessed associations between laboratory findings and treatment decisions. PCR detected at least one potential pathogen in 50.2% of sterile pyuria patients compared to 10% of controls (p < 0.05). Treatment initiation was more frequent in the patient group than in controls (43.3% vs. 30%, p < 0.05). Logistic regression demonstrated that leukocyte counts ≥ 10/ml were significantly associated with PCR positivity (OR = 6.84, p < 0.05) and the physician's treatment decisions (OR = 2.59, p < 0.05). The most common pathogens in patients were Ureaplasma urealyticum (21.9%), Mycoplasma hominis (12.9%), and Gardnerella vaginalis (10.9%), predominantly in adult women with both elevated leukocyte counts and positive LE tests. Although PCR positivity was significantly associated with treatment initiation, the correlation was weak (r = 0.33), indicating that treatment decisions were influenced by additional clinical factors. Molecular testing detected DNA from Ureaplasma, Mycoplasma, and G. vaginalis frequently in sterile pyuria, particularly in adult women; these findings indicate candidate microorganisms requiring clinical correlation.

Background: The landscape of hepatitis C virus (HCV) infection has been changing with the introduction of direct-acting antivirals (DAAs). This study evaluates 15-year temporal trends of anti-HCV and HCV-RNA positivity in a regional referral center in Türkiye, analyzing the impact of DAA treatments, the COVID-19 pandemic, and the 2023 earthquakes on disease dynamics. Methods: Laboratory data of patients tested for anti-HCV antibodies and HCV-RNA between 2011 and 2025 were retrospectively analyzed after excluding repeat records. Positive patients were categorized by antibody titers (1–4.99 S/Co and ≥5 S/Co) and viremia status. Poisson, beta, and quantile regression models were determined annual trends in case numbers, positivity rates, and median ages. Results: A total of 402,557 patients underwent anti-HCV screening over 15 years. While annual test volume increased 2.25-fold, the number and rate of high-titer (≥5 S/Co) positive patients decreased four-fold, significantly. HCV-RNA positivity rates remained stable between 2011 and 2016 but declined sharply from 2017, falling approximately 19.2% annually (p < 0.001). Significant diagnostic disruptions occurred in 2020 (pandemic) and 2023 (earthquakes). An “aging trend” was identified; the median age of viremic patients increased by over 5.5 years throughout the study period. Conclusions: The introduction of DAAs in 2016 marked a milestone, leading to a nearly 90% reduction in the viremic patient burden in our region. The steady aging of the HCV-positive population suggests that the infected pool is shrinking and is not replenished. However, global and regional crises can hinder screening efforts, necessitating resilient public health strategies to achieve World Health Organization 2030 elimination targets.

Onychomycosis is a nail infection most commonly caused by dermatophytes. However in recent years, non-dermatophyte molds have also been increasingly reported as causative agents of onychomycosis. Phoma glomerata is a saprophytic fungus commonly found in nature, which rarely causes infections in humans and to date, only one case has been reported in another country as a causative agent of onychomycosis. In this case report, a case of onychomycosis caused by P.glomerata was presented. A 67-year-old female patient admitted to the dermatology outpatient clinic of our hospital with a oneyear history of discoloration, thickening and fragility of the left big toenail. In the potassium hydroxide microscopic examination of the specimen taken from the nail bed, septate and branched hyphae were observed. Dark brown pigmented, slow-growing mold colonies were observed within 10 days of culture on Sabouraud dextrose agar. Microscopic examination revealed the presence of pycnidial structures. The fungus isolated from the patient was identified as P.glomerata using the VITEK MS Mould Kit with the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) (VITEK MS, bioMérieux, France) system and DNA sequencing analysis was performed to confirm the diagnosis. Following genomic DNA extraction, the 28S rRNA gene region was amplified by polymerase chain reaction (PCR) using the NL1 and NL4 primers. After agarose gel electrophoresis of the PCR products, the amplicons were sequenced using the SQK-NBD114.96 kit on the MinION (Oxford Nanopore, United Kingdom) platform. The obtained data were analyzed using the BLAST algorithm in the National Center for Biotechnology Information GenBank database. The sequence was submitted to the NCBI GenBank under the accession number PV975047. The patient was treated with oral terbinafine (250 mg/day) and topical antifungal therapy. Clinical improvement was observed after two months of follow-up. In this study, we present a case of onychomycosis caused by P.glomerata in an elderly diabetic patient living in a rural area. According to our literature review, this is the first case reported from Türkiye and the second worldwide. Current scientific data suggest that Phoma species can cause infections in the skin, subcutaneous tissues or other organs, especially in immunocompromised or debilitated individuals, or following penetrating trauma. Classical phenotypic methods pose significant challenges in identifying this agent and MALDI-TOF MS or molecular methods may be useful for accurate identification.

Amaç: Arı venomu gerektiğinde kovan savunmasında kullanmak üzere işçi arılar tarafından üretilir. Yapısında melittin ve fosfolipaz A2 başta olmak üzere birçok aktif bileşik vardır. Venomun antimikrobiyal etkinliği özellikle bu iki bileşiğe atfedilmektedir. Bu çalışmada arı venomunun Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus ve Candida albicans üzerindeki antimikrobiyal etkinliğinin araştırılması amaçlanmıştır. Materyal ve Metot: Etken madde olarak Apis mellifera L. cinsi bal arısı tarafından üretilen arı venomunun sulu çözeltisi kullanıldı. Venomun sulu çözeltisi 1 mg/mL olacak şekilde 500 rpm hızda 40oC’de 3 saat manyetik karıştırıcıda karıştırılarak hazırlandı. Elde edilen çözeltinin gram-negatif etkenlerden Escherichia coli ve Pseudomonas aeruginosa; gram-pozitif etkenlerden Staphylococcus aureus ve fungal bir patojen olan Candida albicans’a karşı minimal inhibitör konsantrasyonu (MİK) Avrupa Antimikrobiyal Duyarlılık Testleri Komitesi (EUCAST) kurallarına göre mikrodilüsyon yöntemi ile araştırıldı. Venomun antimikrobiyal özelliği 12,5 µg/mL – 0.006µg/mL konsantrasyon aralığında test edildi. Bulgular: Test edilen arı venomu Escherichia coli, Pseudomonas aeruginosa ve Candida albicans’ın üremesini 3.1 µg/mL, Staphylococcus aureus’un üremesini ise 6,25 µg/mL konsantrasyonda inhibe etmiştir. Sonuç: Çeşitli kanser hücreleri üzerinde sitotoksik etkileri olduğu bilinen arı venomunun bu çalışma ile gram-negatif, gram-pozitif ve Candida türü mantarlara karşı oldukça düşük konsantrasyonlarda üremeyi inhibe edici etki gösterdiği saptanmıştır. Test edilen venom, bu antimikrobik etkisini çalışılan tüm etkenlerde aynı veya çok yakın konsantrasyonda göstermiştir. Sonuç olarak ham arı venomunun antibakteriyel ve antifungal etkinliği olduğu ve bu maddenin apiterapi uygulamaları içerisinde kullanım potansiyeli gösterdiği anlaşılmaktadır.