亚抑菌浓度抗菌药物对多重耐药鲍曼不动杆菌生物膜形成的影响
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篇名: 亚抑菌浓度抗菌药物对多重耐药鲍曼不动杆菌生物膜形成的影响
TITLE:
摘要: 目的:探讨亚抑菌浓度(sub-MIC)抗菌药物对多重耐药鲍曼不动杆菌(MDR-AB)生物膜形成的影响,为临床相关感染的防治提供参考。方法:采用琼脂平板倍比稀释法测定临床分离鲍曼不动杆菌(AB)的最低抑菌浓度(MIC),筛选MDR-AB菌株;采用微孔法分析不同剂量sub-MIC抗菌药物对MDR-AB菌株生物膜形成的影响,并使用AB标准菌株(ATCC 17978)进行验证;采用定量逆转录聚合酶链反应法测定其生物膜形成相关调控基因的表达情况。结果:临床检出的MDR-AB菌株对碳青霉烯类、头孢菌素类、喹诺酮类、氨基糖苷类、四环素类、大环内酯类抗菌药物耐药(MIC≥16 μg/mL),对多黏菌素B和替加环素较敏感(MIC≤8 μg/mL)。不同剂量sub-MIC头孢吡肟、环丙沙星、阿奇霉素、阿米卡星均可显著抑制大多数MDR-AB菌株生物膜的形成,且以阿奇霉素的抑制作用相对最强(其对应菌株的相对生物膜形成值最小);多西环素可显著诱导大多数菌株生物膜的形成,而美罗培南、头孢哌酮、替加环素、庆大霉素、多黏菌素B对其生物膜形成的影响并不明显。验证试验结果显示,与未经药物作用的对照菌株比较,经0.25、0.125 μg/mL阿奇霉素以及0.25 μg/mL阿米卡星作用后,标准菌株的相对生物膜形成值均显著下降(P<0.05),且阿奇霉素的抑制作用呈现一定的量效关系(P<0.05)。基因表达测定结果显示,与未经药物作用的对照菌株比较,经0.25 μg/mL阿奇霉素作用后,bap、filA、pbp-1a、pbp-1b基因的相对表达量均显著下降(P<0.05),而ompA、csuE基因的相对表达量均无显著变化(P>0.05)。结论:我院MDR-AB菌株的耐药情况严重。sub-MIC头孢吡肟、环丙沙星、阿米卡星、阿奇霉素对其生物膜的形成具有明显的抑制作用,其中阿奇霉素的作用最强且呈量效关系。阿奇霉素对MDR-AB菌株生物膜形成的抑制作用可能与其下调bap、filA、pbp-1a、pbp-1b基因的表达有关。
ABSTRACT: OBJECTIVE: To investigate the effects of sub-MIC antibiotics on the biofilm formation of multi-drug resistant Acinetobacter baumannii (MDR-AB), and to provide reference for the prevention and treatment of related infection. METHODS: Agar plate doubling dilution method was used to detect MIC of clinically isolated A. baumannii (AB) and screen MDR-AB. Microporous method was used to analyze the effects of different doses of sub-MIC antibiotics on the biofilm formation of MDR-AB, which was validated by using AB standard strain (ATCC 17978). The expression of biofilm-related gene was detected by RT-PCR. RESULTS: The detected MDR-AB was resistant to carbapenems, cephalosporins, quinolones, aminoglycosides, tetracyclines and macrolides (MIC≥16 μg/mL). It was sensitive to polymyxin B and tegocycline (MIC≤8 μg/mL). Different doses of sub-MIC cefepime, ciprofloxacin, azithromycin and amikacin could significantly inhibit the biofilm formation of MDR-AB, and azithromycin had the strongest inhibitory effect (the relative biofilm formation values of the corresponding strains was minimal). Doxycycline could significantly induce the formation of biofilm in most strains, but meropenem, cefoperazone, tigacycline, gentamicin and polymyxin B had no significant effect on the formation of biofilm. Results of validation test showed that compared with untreated control strains, the relative biofilm formation values of standard strains were decreased significantly after treated with 0.25 and 0.125 μg/mL azithromycin and 0.25 μg/mL amikacin (P<0.05), and inhibitory effect of azithromycin showed a dose-dependent relationship (P<0.05). Results of gene expression detection showed that compared with untreated control strains, relative expression of bap, filA, pbp-1a and pbp-1b gene were decreased significantly (P<0.05), while relative expression of ompA and csuE gene had no significant change (P>0.05). CONCLUSIONS: The drug resistance of MDR-AB strains in our hospital is serious. Sub-MIC cefepime, ciprofloxacin, amikacin and azithromycin shows significant inhibitory effect on biofilm formation, and the inhibitory effect of azithromycin is the strongest, with dose-dependent manner. Azithromycin can inhibit the biofilm formation of MDR-AB which may be associated with the expression down-regulation of bap, filA, pbp-1a and pbp-1b gene.
期刊: 2018年第29卷第22期
作者: 樊莉,孙凤军,枉前,夏培元,周世文
AUTHORS: FAN Li,SUN Fengjun,WANG Qian,XIA Peiyuan,ZHOU Shiwen
关键字: 鲍曼不动杆菌;多重耐药;生物膜;亚抑菌浓度;抗菌药物;阿奇霉素;基因表达
KEYWORDS: Acinetobacter baumannii; Multi-drug resistance; Biofilm; Sub-MIC; Antibiotics; Azithromycin; Gene expression
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