ANAEROBIC BACTERIA ISOLATED FROM CLINICAL SPECIMENS IN A UNIVERSITY HOSPITAL AND RESISTANCE OF ANAEROBIC GRAM-NEGATIVE RODS TO ANTIBIOTICS

Abstract

Objective: Although anaerobic bacteria are normal microbiota members in humans, they can cause endogenous and exogenous infections. The empirical treatment of anaerobic infections is based on reports of susceptibility patterns reported in various studies. This study aims to identify the anaerobic bacteria isolated from clinical samples in 2018 and to determine the resistance of anaerobic Gram-negative rods to antibiotics and to compare the results obtained with the results of anaerobic Gram-negative rods isolated between 2015 and 2017 in the same unit in this study. Material and Method: Specimens were inoculated on Schaedler Agar and Cooked Meat Broth and incubated in anaerobic conditions. Bacteria were identified by colony morphologies, conventional tests and anaerobic diagnostic discs. Antibiotic susceptibility tests were performed using the concentration gradient method and evaluated according to the criteria of CLSI. Results: Of the 1630 clinical samples sent for anaerobic culture, 41 (2.5%) anaerobic bacteria were isolated. Most of the bacteria were isolated from the Department of Gynecology and Obstetrics (29%), Otorhinolaryngology (29%) clinics and mostly abscess specimens (49%). Seventy-one percent of the isolated anaerobic bacteria were Gram-negative and 29% Gram-positive bacteria. The most frequently isolated anaerobic bacteria were Bacteroides fragilis group (24%) and Prevotella spp (22%). Clindamycin resistance was quite high and there was no carbapenem resistance in anaerobic Gram-negative rods, but one third of the isolates were resistant to amoxicillin+clavulanic acid. Conclusion: It was remarkable that more than half of the isolated anaerobic Gram-negative rods, especially the B. fragilis group, were resistant to clindamycin and about a third of amoxicillin+ clavulanate. Increased resistance to these antibiotics used empirically in the treatment of infections caused by anaerobic Gram-negative rods is anticipated to limit antibiotic treatment regimens in the future. Routine monitoring of resistance is necessary for proper empirical treatment.

Keywords

• Anaerobic bacteria
• antibiotic resistance
• .

BİR ÜNİVERSİTE HASTANESİNDE KLİNİK ÖRNEKLERDEN İZOLE EDİLEN ANAEROP BAKTERİLER VE ANAEROP GRAM-NEGATİF ÇOMAKLARIN ANTİBİYOTİKLERE DİRENCİ

Abstract

Amaç: Anaerop bakteriler, insanda normal mikrobiyota üyesi olmakla birlikte endojen ve ekzojen enfeksiyonlara neden olabilmektedir. Anaerobik enfeksiyonların ampirik tedavisi, çeşitli araştırmalarda bildirilen duyarlılık paterni raporlarına dayanmaktadır. Bu çalışmada, 2018 yılında klinik örneklerden izole edilen anaerop bakterilerin tanımlanarak anaerop Gram-negatif çomakların antibiyotiklere direnç durumlarının belirlenmesi ve elde edilen sonuçların aynı birimde 2015-2017 yılları arasında izole edilen anaerop Gram-negatif çomaklara ait sonuçlarla karşılaştırılması amaçlanmıştır. Gereç ve Yöntem: Klinik örnekler Schaedler agar ve kıymalı buyyon besiyerlerine ekilerek anaerop ortam sağlayıcı ile birlikte anaerop ortamda inkübe edilmiştir. Bakteri tanımlaması koloni morfolojisi, konvansiyonel testler ve anaerop tanı diskleri ile yapılmıştır. Antibiyotik duyarlılık deneyleri, konsantrasyon gradiyent yöntemi kullanılarak gerçekleştirilmiş ve CLSI kriterlerine göre değerlendirilmiştir. Bulgular: Anaerop kültür için gönderilen 1630 klinik örnekten 41 (%2,5) anaerop bakteri izole edilmiştir. Anaerop bakteri izole edilen örneklerin en çok Kadın Hastalıkları ve Doğum Kliniği (%29) ve Kulak-Burun-Boğaz (%29) kliniklerinden ve en fazla abse (%49) örneklerinden izole edildiği belirlenmiştir. İzole edilen anaerop bakterilerin %71’inin Gram-negatif, %29’unun Gram-pozitif bakteriler olduğu, en sık izole edilen anaerop bakterilerin Bacteroides fragilis grubu (%24) ve Prevotella cinsi (%22) bakteriler olduğu bulunmuştur. Klindamisin direncinin oldukça yüksek olduğu, anaerop Gram-negatif çomaklarda karbapenem direncinin olmadığı, ancak suşların üçte birinin amoksisilin+klavulanik asite dirençli olduğu bulunmuştur. Sonuç: Özellikle B. fragilis grubunda olmak üzere, izole edilen anaerop Gram-negatif çomakların yarısından fazlasının klindamisine ve yaklaşık üçte birinin amoksisilin+klavulanata dirençli olması dikkat çekicidir. Ampirik olarak kullanılan antibiyotiklere karşı artan direncin, gelecekteki antibiyotik tedavi rejimlerini kısıtlayacağı tahmin edilmektedir. Uygun ampirik tedavi için direncin rutin olarak izlenmesi gereklidir.

Keywords

• Anaerop bakteri
• antibiyotik direnci

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