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    Effects of disinfectants and ciprofloxacin on quorum sensing genes and biofilm of clinical Pseudomonas aeruginosa isolates
    (Elsevier Ltd, 2020) Uzunbayir-Akel, N.; Tekintas, Y.; Yilmaz, F.F.; Ozturk, I.; Okeer, M.; Aydemir, S.S.; Hosgor-Limoncu, M.
    Background: Pseudomonas aeruginosa is one of the most virulent bacteria and quorum sensing (QS) genes have an importance on virulence factors such as biofilm that provide resistance against disinfectants and antibiotics. Objective: This study aimed to determine the minimum inhibitory concentrations of the disinfectants, to investigate the effects of disinfectants and ciprofloxacin on biofilm production mature biofilm of clinical P. aeruginosa isolates, and it was aimed to investigate the effects of the agents on the expression levels of several QS-related genes in the isolates. Methods: Minimum inhibitory concentration (MIC) levels of polyhexamethylene biguanide (PHMB), chlorhexidine (CHX), quaternary ammonium compounds (QAC), glutaraldehyde (GLU) and ciprofloxacin (CIP) against clinical P. aeruginosa isolates were evaluated by microdilution method. Effects of the agents on the biofilm producing capacities of clonally unrelated nine strains were investigated by spectrophotometric method. Alterations in the expression of QS-related genes (lasI, lasR, rhlI and rhlR) were investigated by qPCR in three isolates that were CIP-susceptible and strong biofilm producer. Results: According to microdilution method results, three isolates were found as resistant, one isolate was found as intermediate susceptible and five isolates were found as susceptible to CIP, and CHX (7.81–31.25 ?g/mL) had the lowest MIC against P. aeruginosa. CHX inhibited biofilm production levels of eight of nine isolates, and GLU and CIP inhibited six of nine isolates in the presence of agents at MIC levels. GLU inhibited the mature biofilm levels of three of nine isolates at MIC and MIC/4 levels and four of nine isolates at MIC/2 levels. Expression levels of QS-related genes were reduced or induced in the presence of different disinfectants. Conclusions: More efforts are required to decrease the risk of ineffective and low-dose application of disinfectants and antimicrobials against bacteria. Targeting of QS-related genes may be a reasonable strategy for the inhibition of virulence factors in P. aeruginosa. © 2020
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    The virulence characteristics and epidemiological relationship of clinical pseudomonas aeruginosa isolates
    (Refik Saydam National Public Health Agency (RSNPHA), 2019) Uzunbayir-Akel, N.; Tekintaş, Y.; Yilmaz, F.F.; Öztürk, I.; Ökeer, M.; Aydemir, S.S.; Hoşgör-Limoncu, M.
    Pseudomonas aeruginosa is an opportunistic pathogen that can cause serious infections, especially in health care settings where host defense is impaired. In addition to resistance problem, the different virulence characteristics of these bacteria can change the course of infection and cure. In this study, it was aimed to determine antibiotic susceptibilities, epidemiological relations and virulence factors of clinical P. aeruginosa isolates. Methods: This study was performed, a total of 83 P. aeruginosa isolated from different clinical samples of Ege University Faculty of Medicine Hospital. Antibiotic susceptibilities of isolates were investigated by the VITEK 2 Compact® automated system and epidemiological relations of isolates determined via "Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR)". Phenotypic tests were performed to determine the virulence factors of the selected representatives from each clone. While the "Elastin Congo Red" method was used for the investigation of elastase activity, appropriate methods applied for Protease, DNase, Lipase, Siderophore and Twitching activities to the detect virulence properties phenotypically. The biofilm production of isolates was investigated by crystal violet method, and the quorum sensing (QS) genes thought to be related to biofilm were determined by PCR method. Results: According to results of antibiotic susceptibility test, the highest resistance was observed against imipenem (43,4%) and the lowest resistance was observed against amikacin (14,5%). Isolates were found in 19 unrelated clones according to ERIC-PZR results. Siderophore and elastase production were observed in all of the representative isolates. Protease, lipase and twitching motility were determined at 5, 14 and 15 isolates respectively, no DNAse production was detected. Nine of the 19 representative isolates produced strong biofilms, and the lasI, lasR, rhlR genes were identified in 17, 18, 13 isolates respectively and the rhlI gene was found in all strains. Conclusion: When the data were evaluated, different antibiotic resistant P. aeruginosa isolates which have different resistance profiles were detected at Ege University Faculty of Medicine Hospital. The inclusion of these resistant isolates in epidemiologically unrelated clones suggests that isolates with genotypically different properties are circulating in the clinics. Despite the many virulence factors that can contribute to pathogenesis, it is noteworthy that biofilm production is particularly prevalent in these isolates. This situation has meant that treatment becomes more difficult, as well as being able to colonize on many different surfaces in health care facilities. More extensive studies in both our country and our region could show the resistance profile of P. aeruginosa bacteria and the effects of virulence factors on the severity of infection. © 2019 Refik Saydam National Public Health Agency (RSNPHA).