Trichophyton rubrum klinik izolatlarının hemolitik aktivitesi ve antifungal ilaçlara in vitro duyarlılığının saptanması
Küçük Resim Yok
Tarih
2011
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Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Yüksek morbiditeye sahip dermatofitoz etkenleri arasında yer alan Trichophyton türleri, immün sistem hücreleri üzerine toksik etki gösteren hemolizinler de dahil olmak üzere virülans faktörü olarak kabul edilen çok sayıda enzim salgılamaktadır. Relaps ve kronikleşme oranının yüksek olduğu dermatofitozların tedavisi ise, uygun olmayan antifungal seçimi ve çapraz direncin giderek artması nedeniyle oldukça zorlaşmaktadır. Bu çalışmada, dermatofitoz ön tanılı hastalardan izole edilen Trichophyton rubrum suşlarının hemolitik aktivitesinin araştırılması ve ketokonazol, itrakonazol, sulkonazol, ekonazol ve terbinafine karşı in vitro duyarlılıklarının belirlenmesi amaçlanmıştır. Hastalardan alınan saç, deri ve tırnak örnekleri, potasyum hidroksit ile direkt mikroskobik olarak incelenmiş ve mikolojik kültürleri (mikobiyotik agar ve Sabouraud dekstroz agar besiyerlerinde, 25C ve 37C’de, üç hafta inkübasyon) yapılmıştır. İzolatların hemolitik aktiviteleri, %5 koyun kanlı Columbia agar kullanılarak 25C’de 7-14 gün inkübasyon sonucu değerlendirilmiştir. Hemoliz saptanan besiyerleri hemolitik aktivitenin artması için 37C’de 1-5 gün daha inkübe edilmiştir. Antifungal duyarlılık testi “Clinical and Laboratory Standards Institute (CLSI)” M38-A standartlarına uygun olarak sıvı mikrodilüsyon yöntemi ile çalışılmıştır. Çalışmada, üreaz aktivitesi ve kıl delme testi negatif, patates dekstroz agarda pigmentasyon yapan 79 T.rubrum suşu değerlendirilmiş; suşların 71 (%89.9)’inde hemolitik aktivite saptanmıştır. Elli suş tam olmayan (alfa) hemoliz, 21 suş tam (beta) hemoliz oluştururken, sekiz tanesinde hemoliz görülmemiştir. Büyük kolonilerin daha geniş, küçük kolonilerin ise daha küçük hemoliz zonu oluşturdukları görülmüş; ancak koloninin büyümesi alfa-hemolizi beta-hemolize dönüştürmemiştir. Antifungal duyarlılık testi sonuçlarına göre minimum inhibitör konsantrasyonu (MİK) aralığı, MİK50 ve MİK90 değerleri sırasıyla; ketokonazol için 0.0125-4 ?g/ml, 0.5 ve 2 ?g/ml; itrakonazol için 0.0625-2 ?g/ml, 0.5 ve 1 ?g/ml; sulkonazol için 0.0313-4 ?g/ml, 0.25 ve 1 ?g/ml; ekonazol için 0.0313-0.125 ?g/ml, 0.0313 ve 0.0625 ?g/ml ve terbinafin için 0.0313-0.0313 ?g/ml, 0.0313 ve 0.0313 ?g/ml olarak bulunmuştur. Hemoliz oluşturan ve oluşturmayan izolatların MİK değerleri karşılaştırıldığında, hemolitik aktivite ile MİK değerleri arasında bir ilişki olmadığı görülmüştür. Sonuç olarak çalışmamızda, klinik T.rubrum suşlarına karşı en etkili antifungal ilacın terbinafin olduğu izlenmiş; sıklıkla kullanılan itrakonazolün MİK değerlerinin beklenenden daha yüksek, ekonazolün ise daha düşük olduğu saptanmıştır.
Trichophyton spp. which are among the agents of dermatophytosis with high morbidity, produce many virulence factors including hemolysins that exhibit toxic activity on immune system cells. Since relapses and chronicity are common problems related to dermatophytosis, prompt and appropriate treatment is of crucial importance. However, treatment is getting difficult due to the choice of inappropriate antifungals and increasing rates of cross-resistance among antifungal agents. The aims of this study were to investigate the hemolytic activities of Trichophyton rubrum strains isolated from patients with dermatophytosis and to detect the in vitro susceptibilities of those strains to ketoconazole, itraconazole, sulconazole, econazole and terbinaphine. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on mycobiotic agar and Sabouraud dextrose agar. To determine hemolytic activities of T.rubrum strains, they were subcultured in Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. Antifungal susceptibility testing was done with broth microdilution method guided by Clinical and Laboratory Standards Institute (CLSI) M38-A document. A total of 79 T.rubrum strains which exhibited negative urease and hair perforation tests, yielded pigmentation in potato-dextrose agar, were evaluated in the study. Hemolytic activity was detected in 71 strains (89.9%). Fifty strains showed incomplete (alpha) hemolysis and 21 strains showed complete (beta) hemolysis, whereas hemolysis was absent in eight of the isolates. Larger colonies created a larger zone of hemolysis and the smaller ones created a smaller zone. However, alpha-hemolysis did not turn to beta-hemolysis following further enlargement of the colony. According to antifungal susceptibility testing, the minimum inhibitory concentration (MIC) ranges, MIC50 and MIC90 values were found 0.0125-4 μg/ml, 0.5 and 2 μg/ml for ketoconazole; 0.0625-2 μg/ml, 0.5 and 1 μg/ml for itraconazole; 0.0313-4 μg/ml, 0.25 and 1 μg/ml for sulconazole; 0.0313-0.125 μg/ml, 0.0313 and 0.0625 μg/ml for econazole; 0.0313-0.0313 μg/ml, 0.0313 and 0.0313 μg/ml for terbinaphine, respectively. When the MIC values of hemolytic and non-hemolytic T.rubrum strains were compared, it was detected that hemolytic activity had no effect on MIC values. Our data have indicated that terbinaphine was the most effective antifungal agent against T.rubrum, while MIC values for itraconazole which is in common clinical use, were higher than expected and MIC values for econazole were lower than expected.
Trichophyton spp. which are among the agents of dermatophytosis with high morbidity, produce many virulence factors including hemolysins that exhibit toxic activity on immune system cells. Since relapses and chronicity are common problems related to dermatophytosis, prompt and appropriate treatment is of crucial importance. However, treatment is getting difficult due to the choice of inappropriate antifungals and increasing rates of cross-resistance among antifungal agents. The aims of this study were to investigate the hemolytic activities of Trichophyton rubrum strains isolated from patients with dermatophytosis and to detect the in vitro susceptibilities of those strains to ketoconazole, itraconazole, sulconazole, econazole and terbinaphine. Hair, skin and nail samples of patients were examined with direct microscopy using potassium hydroxide and cultivated on mycobiotic agar and Sabouraud dextrose agar. To determine hemolytic activities of T.rubrum strains, they were subcultured in Columbia Agar with 5% sheep blood and incubated for 7-14 days at 25°C in aerobic conditions. Media which displayed hemolysis were further incubated for 1-5 days at 37°C to increase hemolytic activity. Antifungal susceptibility testing was done with broth microdilution method guided by Clinical and Laboratory Standards Institute (CLSI) M38-A document. A total of 79 T.rubrum strains which exhibited negative urease and hair perforation tests, yielded pigmentation in potato-dextrose agar, were evaluated in the study. Hemolytic activity was detected in 71 strains (89.9%). Fifty strains showed incomplete (alpha) hemolysis and 21 strains showed complete (beta) hemolysis, whereas hemolysis was absent in eight of the isolates. Larger colonies created a larger zone of hemolysis and the smaller ones created a smaller zone. However, alpha-hemolysis did not turn to beta-hemolysis following further enlargement of the colony. According to antifungal susceptibility testing, the minimum inhibitory concentration (MIC) ranges, MIC50 and MIC90 values were found 0.0125-4 μg/ml, 0.5 and 2 μg/ml for ketoconazole; 0.0625-2 μg/ml, 0.5 and 1 μg/ml for itraconazole; 0.0313-4 μg/ml, 0.25 and 1 μg/ml for sulconazole; 0.0313-0.125 μg/ml, 0.0313 and 0.0625 μg/ml for econazole; 0.0313-0.0313 μg/ml, 0.0313 and 0.0313 μg/ml for terbinaphine, respectively. When the MIC values of hemolytic and non-hemolytic T.rubrum strains were compared, it was detected that hemolytic activity had no effect on MIC values. Our data have indicated that terbinaphine was the most effective antifungal agent against T.rubrum, while MIC values for itraconazole which is in common clinical use, were higher than expected and MIC values for econazole were lower than expected.
Açıklama
Anahtar Kelimeler
Mikrobiyoloji
Kaynak
Mikrobiyoloji Bülteni
WoS Q Değeri
Scopus Q Değeri
Cilt
45
Sayı
1
