Zeynep Cizmeci

Carbapenem resistance driven by carbapenemase production in Gram-negative bacteria is a global threat. Carbapenem-resistant Acinetobacter baumannii (CRAb) is a critical priority pathogen listed by the World Health Organization (WHO). While bla _OXA-23 and bla _{OXA-24/40-like} are most frequently reported in CRAb, an increasing prevalence of bla _NDM has been noted in recent years. This study aimed to investigate the distribution of carbapenemase genes among CRAb isolates obtained from three tertiary care centres in Türkiye. A total of 336 CRAb isolates recovered from various clinical specimens (blood, respiratory samples, wound/tissue swabs, urine, and catheter tip samples) between January 2023 and October 2024 were included (Centre-1:198; Centre-2:86; Centre-3:52). Antimicrobial susceptibility testing was performed using the VITEK2 or BD Phoenix system, with additional tests carried out using the disc diffusion or broth microdilution methods. The results were interpreted in accordance with EUCAST criteria. The presence of bla _OXA-51 , bla _OXA-23 , bla _{OXA-24/40-like} , bla _OXA-58 , bla _VIM , bla _IMP , bla _NDM and bla _KPC was tested by qPCR. The clonal relationship among the isolates producing metallo-β-lactamase (MBL) was assessed using AP-PCR and PFGE methods. Our study detected bla _OXA-23 in 305 isolates (90.8%), bla _{OXA-24/40-like} in 88 (26.2%), bla _NDM in 21 (6.3%), and bla _VIM in one isolate. However, bla _OXA-58 , bla _IMP and bla _KPC were not detected. Dual gene combinations were observed in 73 isolates, while triple combinations were identified in three isolates (two bla _NDM / bla _OXA-23 / bla _{OXA-24/40-like} , one bla _VIM /bla _OXA-23 / bla _{OXA-24/40-like} ). AP-PCR/PFGE demonstrated a clonal relationship among 18 isolates, all originating from a single intensive care unit at Centre-1. Because carbapenem resistance is endemic in this unit, the cluster was indistinguishable from the background resistant population and was detected only retrospectively by molecular typing; we therefore describe it as a silent outbreak. In this study bla _OXA-23 and bla _{OXA-24/40-like} were the predominant carbapenemase genes in CRAb, with bla _NDM detected at a notable frequency. The detection of combined gene profiles and inter-centre differences highlight the potential impact of local antibiotic use and infection control practices on the dissemination of resistance, and the clonal cluster identified here shows that such dissemination can go unrecognised in endemic settings.

Background: Candida species are major causes of hospital-acquired bloodstream infections associated with high mortality in critically ill patients. This study aimed to evaluate temporal changes in species distribution, antifungal resistance, clinical outcomes, and mortality predictors in ICU patients with candidemia. Methods: This retrospective study included 250 ICU patients with candidemia between January 2018 and January 2022. The study period was divided into two cohorts (2018–2020, n = 80; 2020–2022, n = 170). Clinical, laboratory, and microbiological characteristics were compared. Multivariable analysis was performed to identify independent predictors of mortality. Results: The incidence density of candidemia significantly decreased from 4.32 to 3.10 per 1,000 ICU patient-days (IRR: 0.72; %95 CI: 0.55–0.94; p = 0,014). A shift toward non-albicans Candida species was observed, while antifungal resistance rates remained stable. Candida score values and empirical antifungal therapy rates were lower in the later period. Despite increased central venous catheter use, catheter-related candidemia decreased. Overall mortality was similar between periods; however, during the second period, mortality was higher in patients with SARS-CoV-2 infection than in those without infection [100/105 (95.2%) vs. 43/65 (66.2%), p < 0.001]. In multivariable analysis, SOFA score was independently associated with mortality in the early period (OR: 1.20, 95% CI: 1.01–1.43; p = 0.043), whereas SARS-CoV-2 infection (OR: 20.43, 95% CI: 3.53–118.14; p = 0.001), Candida score (OR: 0.19, 95% CI: 0.06–0.50; p = 0.003), lactate level at ICU admission (OR: 5.23, 95% CI: 1.55–17.57; p = 0.007), and urea level at ICU admission (OR: 1.01, 95% CI: 1.00–1.02; p = 0.030) were independent predictors in the later period. Conclusion: The high mortality observed among patients with SARS-CoV-2–associated candidemia underscores the need for heightened diagnostic awareness in deteriorating ICU patients. Early diagnostic work-up, timely initiation of antifungal therapy, and reassessment of treatment according to microbiological findings are important in this setting. Hospital-specific identification of preventable risk factors may also help optimize candidemia management and infection control strategies.

Peritonitis presents an inflammation of the peritoneal cavity that can develop because of infectious (bacteria, viruses, parasites, etc.) and non-infectious (chemical agents, foreign substances, etc.) causes. Infectious peritonitis is divided into three classes based on

Background: Carbapenem resistance is one of the major global public health threats caused by the overuse or misuse of carbapenems, which are often the last resort in treating multidrug-resistant infections. Today, timely detection of carbapenemase-producing organisms is critical for infection control. Therefore, rapid and accurate detection of carbapenemases using a cost-effective method with high sensitivity and specificity is essential to guide appropriate treatment and prevent further spread. Objectives: This study aimed to evaluate the sensitivity of the newly developed rapid carbapenemase detection method (rCDM) with isolates whose resistance genes were determined by molecular methods and to compare it with the modified carbapenem inactivation method (mCIM), whose diagnostic performance characteristics are well-defined. Methods: A total of 130 Klebsiella pneumoniae isolates (65 carbapenem-susceptible, 65 carbapenem-resistant) from various clinical specimens were included in the study. Identification and antibiotic susceptibility testing of the isolates was performed using the BD Phoenix™ automated system. Phenotypic carbapenemase detection methods, mCIM and rCDM, were studied for all carbapenem-sensitive and carbapenem-resistant isolates with known resistance genes. Results: Among carbapenem-resistant K. pneumoniae isolates, blaOXA-48 was the most frequently detected resistance gene (78%). Using PCR results as the reference method, the sensitivity of rCDM was 100%. When rCDM and mCIM results were compared, both phenotypic methods were 100% compatible, with no statistically significant difference observed. Conclusions: Rapid carbapenemase detection method is a rapid and reliable phenotypic carbapenemase detection method with high sensitivity. Its ease of use and interpretation make it suitable for use in laboratories with limited resources. Additionally, its excellent performance in detecting common carbapenemase types and high consistency with mCIM support its utility in various laboratory settings without requiring additional materials or technical infrastructure.

Objective: We aimed to define the clinical features and antimicrobial susceptibility profiles of Burkholderia cepacia complex infections and to determine the predictors for mortality. Materials and Methods: Our single-center retrospective study included patients with nosocomial B. cepacia complex infection between 2018 and 2022. We evaluated the predictors of 14-day and 28-day mortality by analyzing clinical and microbiological data. Results: A total of 87 patients were included. Most infections (79.3%) occurred in the intensive care units (ICUs). Among B. cepacia complex isolates, 74.7% were susceptible to trimethoprim-sulfamethoxazole, 70.3% to levofloxacin, 50% to meropenem, and 23.4% to ceftazidime. The rates of 14-day mortality, 28-day mortality, and in-hospital mortality were 41.3% (n=36), 52.8% (n=46), and 64.3% (n=56), respectively. Multivariate analysis revealed neutrophil/lymphocyte ratio (NLR) (odds ratio [OR]=1.05, p=0.024), platelet count (OR=1.00, p=0.011), creatinine (OR=2.14, p=0.006), and aspartate aminotransferase (AST) (OR=1.02, p=0.028) as predictors for 14-day mortality. In addition to NLR (OR=1.07, p=0.014), platelet count (OR=1.00, p=0.039), creatinine (OR=2.05, p=0.008), and AST (OR=1.02, p=0.035), procalcitonin (OR=1.05, p=0.049) was also found as an independent predictor for 28-day mortality. In receiver operating characteristic (ROC) curve analysis for predicting 14-day mortality, area under the ROC curve (AUC) values were 0.684 (p=0.003) in NLR, 0.719 (pp=0.003) in procalcitonin, 0.743 (ppp=0.002) in NLR, 0.651 (p=0.010) in platelet count, 0.638 (p=0.020) in procalcitonin, 0.730 (pp=0.001) in AST. Conclusion: Increasing antibiotic resistance and higher mortality rates justify that B. cepacia complex is a significant threat to hospitalized patients, especially in ICUs. Elevated levels of NLR, AST, creatinine, procalcitonin, and decreased platelet may predict poor clinical outcomes and could help clinicians in the management of this notorious bacterial pathogen. Keywords: antimicrobial susceptibility, antibiotic resistance, Burkholderia cepacia complex, mortality, predictors

We aimed to characterize carbapenem-resistant isolates in a tertiary hospital in Istanbul, Turkey, high-prevelance area for OXA-48 producers. About 76 Enterobacteriaceae clinical isolates were included. Carbapenemase production was detected by Carbapenem Inactivation Method and carbapenemase genes were investigated by PCR. The clonal relationships were evaluated by AP-PCR. Nineteen Klebsiella pneumoniae isolates were colistin resistant. About 75 isolates yielded carbapenemase by CIM. 52 OXA-48, 17 NDM-1 and 2 VIM-5 carbapenemase genes were detected. Co-production of ‘OXA-48 and NDM-1’ and ‘OXA-48 and VIM-5’ were demonstrated in two Klebsiella pneumoniae isolates. The total clustering rate was 20.2%. About 69 Klebsiella pneumoniae yielded 60 profiles and 12 isolates formed five clusters. We have demonstrated the presence of OXA-48 carbapenemases in the majority of isolates in a large collection of carbapenemase-producing isolates from a single hospital. The relatively high rates of NDM-1-producing isolates and colistin resistance is noteworthy.

The aim of this study was to assess species distribution, antifungal susceptibility and clonal relationships among Candida strains isolated from a group of pediatric/neonatal intensive care (PICU/NICU) patients that had a very high mortality rate (76%). The cases of 21 patients (19 with candidemia, 2 with Candida meningitides) treated over a 1-year period in a Turkish hospital PICU and NICU were retrospectively analyzed. Twenty-eight Candida isolates were detected from blood (20), cerebrospinal fluid (CSF) (2) and other specimens (6). Candida species were identified using the API ID 32C System. Susceptibility testing was done (all 28 isolates) for amphotericin B, fluconazole and itraconazole using the broth microdilution method. Arbitrarily primed polymerase chain reaction (AP-PCR) was used for molecular typing of the 3 most common ones; C. albicans (15), C. parapsilosis (6), and C. pelliculosa (4). Electrophoretic karyotyping (EK) was done to check clonal identity obtained by AP-PCR. Of the 20 blood isolates, 8 (40%) were C. albicans, 12 (60%) were non-albicans Candida, and one of the 2 CSF isolates was C. albicans. The overall species distribution was as follows: 15 C. albicans isolates, 6 C. parapsilosis isolates, 4 C. pelliculosa isolates, 2 C. famata isolates and 1 C tropicalis isolate. Amphotericin B had the best antifungal activity with a MIC90 of 0.125 microg/ml, and the rates of susceptibility to fluconazole and itraconazole were 93% and 82%, respectively. AP-PCR revealed 11 genotypes (4 were identical pairs, 7 were distinct) among the 15 C. albicans isolates, 2 genotypes (5 were classified in the same type) among the 6 C. parapsilosis isolates, and 4 separate genotypes for the 4 C. pelliculosa isolates. Karyotyping results correlated well with the AP-PCR findings. As indicated in the previous research, our results confirmed that non-albicans Candida species have become more frequently causative agents for invasive fungal infections in the ICU. Transmission of C. albicans and C. pelliculosa was relatively low, but transmission of C. parapsilosis was high, suggesting that more effective control and very strict treatment protocols are needed for patients having high mortality and invasive fungal infection in ICU.