Buket TOKSOY, Banu BAYRAKTAR, Emin BULUT, Fesem BAŞARI

Klinik örneklerden izole edilen Streptococcus pneumoniae suşlarının çeşitli antibiyotiklere duyarlılıkları

Çeşitli klinik örneklerden infeksiyon etkeni olarak izole edilen ardışık 70 Streptococcus pneumoniae suşunun başta penisilin olmak üzere, eritromisin, klindamisin, tetrasiklin, SXT, levofloksasin, vankomisine duyarlılıklarının incelenmesi amaçlanmıştır. Çalışmaya katılan 70 suşun 13’ünde (% 19) orta düzey penisilin direnci (ODPD) bulunmuş, yüksek düzey penisilin direnci (YDPD) görülmemiştir. Diğer antibiyotiklere direnç oranları SXT için % 41, eritromisin için % 23, klindamisin için % 17, tetrasiklin için % 34 ve levofloksasin % 3 olarak saptanmıştır. Tüm suşlar vankomisine duyarlı bulunmuştur. Penisiline duyarlı suşlarda aynı antibiyotiklere ait direnç oranları sırasıyla % 33, % 16, % 14, % 30, % 4 olarak; ODPD görülen suşlarda ise sırasıyla % 77, % 54, % 31, % 54, % 0 olarak saptanmıştır. CLSI rehberinde (2008) infeksiyonun lokalizasyonuna göre parenteral penisilinler için yeni MİK değerleri belirlenmiştir. Menenjit dışı infeksiyonlarda yeni duyarlı, orta ve dirençli MİK sınır değerleri sırasıyla ≤2 μg/ml, 4 μg/ml, ≥ 8 μg/ml’dir. Bu kriterlere göre çalışmamızda parenteral penisilinlere karşı orta veya yüksek düzey dirençli bir suş saptanmamıştır. Bu sınır değerlerin kullanılması halen tedaviye penisilinle devam edilebilmesi ve dolayısıyla diğer antibiyotiklere direnç gelişiminin önlenmesi açısından önem arz etmektedir.

Antibacterial susceptibility of Streptococcus pneumoniae strains isolated from clinical specimens

In this study, aim is to determine mainly penicillin susceptibility of consecutive 70 Streptococcus pneumoniae strains isolated from various clinical samples as infectious pathogens. Erythromycin, clindamycin, tetracycline, SXT, levofloxacin, vancomycin susceptibilities of these strains were also determined. Thirteen of 70 strains (19 %) showed intermediate level resistance to penicillin whereas no high level penicillin resistant strain was detected. Resistance rates for other antimicrobials were as follows; SXT 41 %, erythromycin 23 %, clindamycin 17 %, tetracycline 34 % and levofloxacin 3 %. Vancomycin resistance was not detected. In penicillin susceptible strains, resistance rates to antibiotics mentioned above were 33 %, 16 %, 14 %, 30 %, 4 %, and in intermediate level penicillin resistant strains these rates were 77 %, 54 %, 31 %, 54 %, 0 %, respectively. In 2008 CLSI guideline new MIC breakpoints for intravenous penicillins were established according to infection sites. For the infections except meningitis; the new breakpoints for susceptible, intermediate and resistant strains are ≤ 2 μg/ml, 4 μg/ml and ≥ 8 μg/ml, respectively. According to these breakpoints, there was no intermediatly penicillin resistant or resistant strain in our study. The changes in penicillin breakpoints enable to continue the treatment of nonmeningitis pneumococcal infections with penicillin and to avoid emergence of resistance against other antimicrobial agents.

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