[Investigation of Biofilm Formation, Anti-Quorum Sensing Activity and Antimicrobial Resistance in Corynebacterium Species Isolated from Clinical Samples]. / Klinik Örneklerden Izole Edilen Corynebacterium Türlerinde Biyofilm Olusumunun, Anti-Quorum Sensing Aktivitesinin ve Antimikrobiyal Direnç Durumunun Arastirilmasi.

An increasing number of different clinical infections caused by Corynebacteria have been reported in the last decade. The aim of this study was to evaluate the antibiotic resistance rates, biofilm formation capacities and to investigate the ''anti-quorum-sensing (anti-QS)'' activities of corynebacteria, which were divided into three groups according to the type of growth in culture (pure, with another pathogenic bacterium and polymicrobial growth). In total 240 Corynebacterium spp. isolates from different clinical specimens sent to the medical microbiology laboratories of Düzce University Faculty of Medicine Hospital and Basaksehir Çam and Sakura City Hospital between June 2021 and June 2022 were classified into three groups: pure, isolated with another pathogen and polymicrobial, according to their growth patterns in culture. Bacteria were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) Biotyper (Bruker, Germany) at an external centre. Antibiotic susceptibilities were determined by disc diffusion method and for vancomycin broth microdilution method was used. Results were interpreted according to EUCAST recommendations. The biofilm-forming properties of the isolates were determined quantitatively. Bioactive components of 17 isolates with strong biofilm formation were extracted and anti-QS activity was determined by agar diffusion method using Chromobacterium violaceum ATCC 12472 strain and then violacein pigment production was measured quantitatively. Of the 240 Corynebacterium spp. isolates, 138 (58%) were pure, 52 (22%) were isolated with another pathogen and 50 (20%) were part of a polymicrobial infection. Of the isolates, 140 were identified as C.striatum, 34 as C.amycolatum and 24 as Corynebacterium afermentans. When the antibiotic resistance rates of the Corynebacterium isolates were analysed according to the groups, the resistance rates to rifampicin and tetracycline antibiotics were found to be statistically significantly lower in the polymicrobial group than in the other groups. The resistance rates to penicillin, clindamycin, ciprofloxacin, moxifloxacin, rifampicin, tetracycline and linezolid were 96.7%, 88.3%, 86.3%, 73.8%, 62.5%, 59.2% and 0.8%, respectively. While all isolates were susceptible to vancomycin, linezolid resistance was detected in two C.afermentans isolates. When the biofilm formation ability was analysed, it was observed that 87 (36.3%) isolates formed biofilm. The biofilm formation rate of the isolates in the polymicrobial growth group was lower than the other two groups. The anti-QS activity of 17 isolates with strong biofilm formation was investigated and none of the Corynebacterium extracts tested were found to have anti-QS activity (inhibition of violacein pigment production without inhibiting bacterial growth) in the QS study with C.violaceum, whereas five isolate extracts had antibacterial activity (inhibition of bacterial growth). Four of the bacterial extracts with antimicrobial activity belonged to C.amycolatum and one to C.afermentans. In conclusion, when both antibiotic resistance rates and biofilm formation rates were analysed, the corynebacteria growing in culture with another pathogen showed similar characteristics to the corynebacteria growing as a pure culture. Therefore, it was thought that corynebacteria growing with another pathogen should not be ignored. In addition, the antimicrobial effects of some corynebacterial extracts suggested that more QS studies should be carried out with microbiota bacteria.

Comparative analysis of different loop types for urine culture collection: Implications for quantitative bacterial growth and culture results.

We hypothesized that the loop material and size could affect the results of the culture when compared to the calibrated pipette. A total of 484 urine samples were included in the study, and each sample was plated by using different loop types and the calibrated pipette. The bacterial counts per milliliter were calculated and compared, with a focus on the important cutoff values of 10³ and 104 CFU/ml for further identification. When considering the 10³ CFU/ml as cutoff value, 1 µl and 10 µl plastic loops gave the highest sensitivity (86.8 %), whereas the 10 µl metal loop had the lowest sensitivity (64.2 %). For the 104 CFU/ml cutoff value, 1 µl plastic loop inoculation demonstrated the highest sensitivity (75.9 %), while the 10 µl metal loop provided the lowest sensitivity (26.5 %). These results suggest that the single use plastic loops are functional, sensitive, useful especially for critical sample.

[NA Rare Bacterial Pathogen in a Patient with Perihilar Cholangiocarcinoma: Erwinia persicina; First Case From Turkey]. / Perihiler Kolanjiyokarsinomlu Hastada Nadir Bir Bakteriyel Patojen: Erwinia persicina; Türkiye'den Bildirilen Ilk Olgu.

Members of the Erwiniaceae family, which can be found saprophytic in humans, have been identified several times as an infectious agent after their first identification in 1920. Erwinia persicina was first identified as a plant pathogen by being isolated from cucumber, tomato and banana in 1990, and it was shown to cause disease in many plant species in the following years. E.persicina was diagnosed as a urinary tract infection agent in an 88-year-old female patient in 1998. Our case, a 30-year-old male patient, was hospitalized for perihilar cholangiocarcinoma while being examined with the complaint of abdominal pain. In preparation for the operation, external drainage from the left lobe biliary tract was performed. The same bacterial growth was detected in the three bile fluid cultures of the patient taken on different dates. The bacterium was identified as E.persicina by MALDI-TOF Microflex LT/SH Smart MS (Bruker Daltonics, Germany) and Erwinia rhapontici with VITEK MS (Biomerieux, France), Rahnella aquatilis with VITEK 2 automated system, Pantoea agglomerans with BD Phoenix™ M50 (BD Diagnostics, USA) automated system. E.persicina identification was also obtained by Sanger sequencing. Antibiotic susceptibility results were evaluated according to the non-species related breakpoints criteria of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). While resistance was found to cefuroxime and cefazolin, the isolate was found to be sensitive to many other beta-lactam antibiotics, quinolones and aminoglycosides. E.persicina is a bacterium that is rarely isolated as an infectious agent in humans. The reason for this may be that it is a plant pathogen on the one hand, and mistakes made in its diagnosis on the other. Many identification systems do not have this bacterium in their library. In this case report, our aim was to emphasize that mistakes made in the diagnosis of E.persicina may play a role in the rare occurence of the agent.

[Three Candida auris Case Reports from Istanbul, Turkey]. / Türkiye Istanbul'dan Bildirilen Üç Candida auris Olgusu.

Candida auris is a fungal pathogen that was first identified in 2009. Since its definition, it has spread globally and has caused life-threatening nosocomial infections. Increases in the number of immunocompromised individuals, empirical use of broad-spectrum antimicrobials and widespread use of catheterizations are the predisposing factors in the development of infection. There are problems for the identification of C.auris with the routine methods. In this case report, infections with C.auris, isolated for the first time from three patients in our hospital's intensive care units (ICU) between November 2020-January 2021, were presented. The first case was a 46-year-old male patient with laryngeal carcinoma who developed cardiopulmonary arrest during anesthesia induction in the tumor operation, and was followed up in the ICU. C.auris growth was detected in the blood and intravenous (IV) catheter tip cultures on the 66th day of admittance. Cure achieved on the 24th day under caspofungin treatment as no growth was determined. Second case was a 71-year-old female patient admitted to the emergency department with shortness of breath and general condition disorder that developed after COVID-19 infection and hospitalized in ICU with the diagnosis of pneumonia and acute renal failure. In the 16th day of admittance C.auris growth was detected in blood and from catheter tip cultures and the patient died in the 18th day. The third case was a 49-year-old male patient, followed up in ICU with the diagnosis of subarachnoid hemorrhage after he admitted to the emergency department with confusion. In the 35th day of admittance, 100000 CFU/ mL C auris growth was detected in urine culture. The patient was accepted as asymptomatic fungiuria and followed up in the ICU. It was determined that the three patients were intubated, had urinary and femoral venous catheters and were being followed under wide spectrum antibiotherapy when the growth of C.auris was detected. Isolates identified as C.auris by MALDI-TOF Microflex LT/SH Smart MS in the Medical Microbiology Laboratory were then confirmed by conventional methods and DNA sequencing in the National Mycology Reference Laboratory. Antifungal susceptibility tests were performed by broth microdilution method. Fluconazole MIC values were >256 mg/ml for all cases. Long-term survival in hospital environments, colonization on skin, resistance to disinfectants of C.auris, facilitate the spread of the fungi and resistance to antifungals lead to treatment failures. In this case report, it was aimed to draw attention to the infections with C.auris, its diagnosis and risk factors.

Nasal care in intensive care unit patients.

PURPOSE: The aim of this study was to investigate nasal hygiene in intensive care patients and improve patient care using isotonic saline nasal spray. MATERIAL AND METHODS: In the study group, over a period of tendays saline nasal spray was administered four times daily. Nasal treatment was not given to the control group. Each patient was examined with a flexible nasopharyngoscope before and after the treatment and a nasal culture was taken. RESULTS: In the study group, the secretion score (1- absent; 2- serosal; 3- seropurulent and 4- purulent) mean value improved from 1.9 to 1.4. In the control group, the secretion score mean value had risen from 1.7 to 3.1. At the beginning of the study, there was no difference in secretion scores between the groups, but on the tenth day a statistically significant difference was found. CONCLUSION: The use of saline nasal spray in this group of intensive care patients was found to be effective in achieving nasal hygiene.