Studying the Frequency of Stenotrophomonas Maltophilia From Different Clinical Samples and Determining the Antimicrobial Susceptibility Pattern of Isolates; بررسی فراوانی استنوتروفوموناس مالتوفیلیا از نمونه های بالینی مختلف و تعیین الگوی حساسیت میکروبی ایزول هها



Torabinejad S ; Deilamani MO ; Nikkhahi F ; Bigverdi R ; Fardsanei F
Source: Journal of Payavard Salamat Published:2025

Abstract

Background and Aim: Stenotrophomonas maltophilia is a non-fermentative Gram-negative bacillus and the third most common cause of hospital-acquired infections. Treatment of infections caused by this bacterium has not always been successful due to its high potential for multiple resistance to a wide range of antibiotics and the formation of biofilms. Obviously, accurate and timely diagnosis of bacterial agents causing hospital-acquired infections and determination of the microbial susceptibility pattern of isolates can make a significant contribution to infection control in hospitals. Therefore, the aim of this study was to determine the frequency of Stenotrophomonas in different clinical samples and to determine the biofilm production rate and microbial susceptibility of isolates. Materials and Methods: In a cross-sectional descriptive study, non-fermentative Gram-negative isolates suspected of being Stenotrophomonas maltophilia isolated from different clinical samples from teaching hospitals in Qazvin province were collected and examined from April to March 2023. After phenotypic and molecular confirmation of the isolates using standard methods, the microbial susceptibility pattern of the isolates and the amount of biofilm production were examined using the microplate titer method. Results: In this study, out of 50 isolates collected, the highest number of isolates were isolated from blood culture (33 isolates) and the lowest number of isolates were isolated from urine samples (1 isolate). Also, the highest frequency of samples was reported from the emergency department with 32 samples (63.8%) and the lowest frequency was reported from the ENT and oncology departments, each with 1 sample (0.8%). All isolates were 100% resistant to imipenem and meropenem due to the inherent resistance of this bacterium to carbapenems, which was a confirmation in the identification of this bacterium. The highest sensitivity to the antibiotics levofloxacin, minocycline and cotrimoxazole was observed with a frequency of 90%, 88% and 84%, respectively. The highest resistance to the antibiotic ceftazidime was observed, which was reported as 88%. In this study, 70% of the strains produced strong biofilms. Conclusion: In this study, we saw an increase in hospital infections caused by Stenotrophomonas maltophilia in clinical samples of Qazvin hospitals. Knowledge of the frequency of opportunistic pathogens causing hospital infections and the microbial sensitivity of isolates leads to control of infections caused by these pathogens, proper treatment of infections and reduction of mortality in hospitalized patients. Fortunately, in this study, the isolates had high sensitivity to fluoroquinolone family antibiotics and antimetabolites. © 2025 Elsevier B.V., All rights reserved.