大熊猫源产碳青霉烯酶肺炎克雷伯菌的耐药性和致病性研究

Study on antibiotic resistance and pathogenicity of carbapenem-resistant Klebsiella pneumoniaes isolated from giant panda

为了掌握产碳青霉烯酶肺炎克雷伯菌(CRKP)在圈养大熊猫中的流行、耐药和致病情况,本研究采用碳青霉烯酶Carba NP检测法从178株大熊猫源肺炎克雷伯菌中分离鉴定出8株CRKP(4.5%)。进一步采用纸片扩散法(K-B法)和PCR技术分别对CRKP分离株进行耐药性和碳青霉烯酶基因型研究,随机选取其中一株CRKP分离株E28研究其对小鼠的致病性。结果显示大熊猫源CRKP对氨曲南、卡那霉素、庆大霉素、氧氟沙星和诺氟沙星敏感,对碳青霉烯类抗生素耐药严重,其中对亚胺培南耐药率(87.5%)高于美罗培南(12.5%);6株CRKP的碳青霉烯酶基因型为blaKPC2-13酶型,2株为bla KPC2-13+bla NDM-1酶型;CRKP分离株E28对小鼠的半数致死量(LD50)为5.6×10^(7)cfu/mL。本研究首次证实CRKP存在于圈养大熊猫中,在大熊猫的临床治疗中应合理使用抗生素,避免CRKP进一步扩散。

The aims of this study were to understand the prevalence,antibiotic resistance and pathogenicity of carbapenemresistant Klebsiella pneumoniae(CRKP)in captive giant pandas.In this study,eight CRKP strains(4.5%)were identified from 178Klebsiella pneumoniae strains isolated from giant pandas by carbapenemase Carba NP assay;the CRKP isolates were further studied for antibiotic resistance and carbapenem genotype by the disk diffusion method(K-B method)and PCR technology,respectively;one of the CRKP isolates,E28,was randomly selected to study its pathogenicity in mice.The results showed that CRKP strains from giant pandas were sensitive to aztreonam,kanamycin,gentamicin,ofloxacin and norfloxacin,and had serious antimicrobial resistant to carbapenem.The antimicrobial resistance rate of imipenem(87.5%)was higher than that of meropenem(12.5%).Among the eight CRKP strains,six strains were KPC2-13 positive,and the remaining two strains all produced the KPC2-13 and NDM-1 carbapenemases.The median lethal dose(LD;)for mice of E28 was 5.6×10^(7)cfu/m L.This study is the first to confirm that CRKP has existed in the captive giant panda population,and antibiotics should be used reasonably in the clinical treatment of giant pandas to avoid further increase and spread.