Bir Şehir Hastanesinde Klinik Örneklerden İzole Edilen Stenotrophomonas maltophilia Suşlarının Antibiyotik Direnç Profilleri ve Epidemiyolojik Eğilimlerinin İncelenmesi (2023–2025)

Abstract

Stenotrophomonas maltophilia, sahip olduğu doğal ve kazanılmış çoklu antibiyotik direnç mekanizmaları nedeniyle sağlık hizmetleri ile ilişkili enfeksiyonlarda giderek önem kazanan fırsatçı bir patojendir. Bu çalışma, 2023 2025 yılları arasında bir şehir hastanesinde klinik örneklerden izole edilen S. maltophilia suşlarının antibiyotik direnç profillerini ve epidemiyolojik eğilimlerini değerlendirmeyi amaçlamaktadır. Retrospektif ve tanımlayıcı nitelikteki bu çalışmada, klinik örneklerden elde edilen tekrarsız S. maltophilia izolatları incelenmiştir. Tür tanımlaması Bruker SMART MALDI Biotyper MALDI TOF MS sistemi ile yapılmıştır. Trimetoprim sülfametoksazol (SXT) ve levofloksasin (LEV) duyarlılığı BD Phoenix M50 otomatize sistemi ve disk difüzyon yöntemiyle belirlenmiş; sonuçlar güncel CLSI/EUCAST kriterlerine göre yorumlanmıştır. Seftazidim için minimum inhibitör konsantrasyon (MİK) değerleri gradient test (bioMérieux Etest) ile belirlenmiştir. Tanımlayıcı istatistikler Microsoft Excel 16.0 ve IBM SPSS Statistics 26.0 programları kullanılarak yapılmıştır. Toplam 1.745 benzersiz S. maltophilia izolatı analiz edilmiştir. İzolatların çoğu erişkin yoğun bakım ünitelerinden (%49,2) ve solunum yolu örneklerinden (%62,4) elde edilmiştir. Genel direnç oranları SXT için %6,0, LEV için %9,2 olup, SXT direncinde yıllar içinde hafif bir azalma eğilimi gözlenmiştir. Seftazidim için MİK₅₀ değeri 16 mg/L, MİK₉₀ değeri ise >256 mg/L olarak bulunmuştur. S. maltophilia, özellikle yoğun bakım ve solunum yolu örneklerinde izole edilen önemli bir sağlık hizmeti ile ilişkili patojen olmaya devam etmektedir. SXT’ye karşı düşük ve azalma eğilimindeki direnç oranı, bu ajanın halen etkili bir tedavi seçeneği olduğunu göstermektedir. Direnç gelişiminin önlenmesi için düzenli sürveyans ve akılcı antibiyotik kullanımı büyük önem taşımaktadır.

Keywords

• Stenotrophomonas maltophilia
• antibiyotik direnci
• trimetoprim-sülfametoksazol
• levofloksasin
• epidemiyoloji

Investigation of the Antibiotic Resistance Profiles and Epidemiological Trends of Stenotrophomonas maltophilia Strains Isolated from Clinical Specimens in a City Hospital (2023–2025)

Abstract

Stenotrophomonas maltophilia has emerged as an important opportunistic pathogen associated with healthcare related infections due to its intrinsic and acquired multidrug resistance mechanisms. This study aimed to evaluate the antibiotic resistance profiles and epidemiological trends of S. maltophilia isolates obtained from clinical specimens in a city hospital between 2023 and 2025. This retrospective, descriptive study included non duplicate S. maltophilia isolates recovered from various clinical samples. Identification was performed using the Bruker SMART MALDI Biotyper MALDI TOF MS system. Antimicrobial susceptibility to trimethoprim sulfamethoxazole (SXT) and levofloxacin (LEV) was determined by the BD Phoenix M50 automated system and disk diffusion, interpreted according to current CLSI/EUCAST criteria. Ceftazidime minimum inhibitory concentrations (MICs) were determined by gradient test (bioMérieux Etest). Descriptive analyses were performed using Microsoft Excel 16.0 and IBM SPSS Statistics 26.0. A total of 1,745 unique S. maltophilia isolates were analyzed. Most isolates originated from adult intensive care units (49.2%) and respiratory samples (62.4%). Overall resistance rates were 6.0% for SXT and 9.2% for LEV, with a slight decreasing trend in SXT resistance over the study period. For ceftazidime, the MIC₅₀ was 16 mg/L and the MIC₉₀ was >256 mg/L. S. maltophilia remains a significant healthcare associated pathogen, predominantly isolated from intensive care and respiratory specimens. The low and decreasing resistance rate to SXT indicates that this agent remains an effective treatment option. Regular surveillance and rational antibiotic use are crucial to prevent the development of resistance.

Keywords

• Stenotrophomonas maltophilia
• antibiotic resistance
• trimethoprim-sulfamethoxazole
• levofloxacin
• epidemiology

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