Klebsiella pneumoniae is a common cause of nosocomial infections. Antibiotic resistance and ability to form biofilm, as two key virulence factors of K. pneumoniae, are involved in the persistence of infections. The purpose of this study was to investigate the correlation between antimicrobial resistance and biofilm formation capability among K. pneumoniae strains isolated from hospitalized patients in Iran. Over a 10-month period, a total of 100 non-duplicate K. pneumoniae strains were collected. Antibiotic susceptibility was determined by Kirby–Bauer disk diffusion method according to CLSI. Biofilm production was assessed by tissue culture plate method. Finally, polymerase chain reaction was conducted to detect four families of carbapenemase: blaIMP, blaVIM, blaNDM, blaOXA−48; biofilm formation associated genes: treC, wza, luxS; and K. pneumoniae confirming gene: rpoB. Most of the isolates were resistant to trimethoprim-sulfamethoxazole (52 %), cefotaxime (51 %), cefepime (43 %), and ceftriaxone (43 %). Among all the 100 isolates, 67 were multidrug-resistant (MDR), and 11 were extensively drug-resistant (XDR). The prevalence of the blaVIM, blaIMP, blaNDM, and blaOXA−48 genes were 7 , 11 , 5 , and 28 %, respectively. The results of biofilm formation in the tissue culture plate assay indicated that 75 (75 %) strains could produce biofilm and only 25 (25 %) isolates were not able to form biofilm. Among these isolates, 25 % formed fully established biofilms, 19 % were categorized as moderately biofilm-producing, 31 % formed weak biofilms, and 25 % were non-biofilm-producers. The antimicrobial resistance among biofilm former strains was found to be significantly higher than that of non-biofilm former strains (p < 0.05). Molecular distribution of biofilm formation genes revealed that 98 , 96 , and 34 % of the isolates carried luxS, treC, and wza genes, respectively. The rise of antibiotic resistance among biofilm-producer strains demonstrates a serious concern about limited treatment options in the hospital settings. All of the data suggest that fundamental actions and introduction of novel strategies for controlling of K. pneumoniae biofilm-related infections is essential.

中文翻译：

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伊朗住院患者分离的肺炎克雷伯菌菌株抗菌素耐药性与生物膜形成能力的相关性

肺炎克雷伯菌是医院感染的常见原因。作为肺炎克雷伯菌的两个关键毒力因子，抗生素耐药性和形成生物膜的能力与感染的持续性有关。本研究的目的是调查从伊朗住院患者中分离出的肺炎克雷伯菌菌株的抗菌素耐药性与生物膜形成能力之间的相关性。在 10 个月的时间里，共收集了 100 株非重复肺炎克雷伯菌菌株。根据 CLSI，通过 Kirby-Bauer 圆盘扩散法确定抗生素敏感性。通过组织培养板方法评估生物膜产生。最后进行聚合酶链反应检测碳青霉烯酶的四个家族：blaIMP、blaVIM、blaNDM、blaOXA-48；生物膜形成相关基因：treC、wza、luxS；和 K。肺炎链球菌确认基因：rpoB。大多数分离株对甲氧苄啶-磺胺甲恶唑 (52 %)、头孢噻肟 (51 %)、头孢吡肟 (43 %) 和头孢曲松 (43 %) 耐药。在所有 100 株分离物中，67 株为多重耐药（MDR），11 株为广泛耐药（XDR）。blaVIM、blaIMP、blaNDM 和 blaOXA-48 基因的流行率分别为 7%、11%、5% 和 28%。组织培养板试验中生物膜形成的结果表明，75 (75%) 株菌株可以产生生物膜，只有 25 (25%) 株不能形成生物膜。在这些分离株中，25% 形成了完全建立的生物膜，19% 被归类为中度产生生物膜，31% 形成弱生物膜，25% 是非生物膜产生者。发现生物膜前菌株的抗菌素耐药性显着高于非生物膜前菌株（p < 0.05）。生物膜形成基因的分子分布显示，98%、96% 和 34% 的分离株分别携带 luxS、treC 和 wza 基因。生物膜产生菌株中抗生素耐药性的上升表明了对医院环境中有限的治疗选择的严重关注。所有数据表明，控制肺炎克雷伯菌生物膜相关感染的基本行动和新策略的引入是必不可少的。生物膜产生菌株中抗生素耐药性的上升表明了对医院环境中有限的治疗选择的严重关注。所有数据表明，控制肺炎克雷伯菌生物膜相关感染的基本行动和新策略的引入是必不可少的。生物膜产生菌株中抗生素耐药性的上升表明了对医院环境中有限的治疗选择的严重关注。所有数据表明，控制肺炎克雷伯菌生物膜相关感染的基本行动和新策略的引入是必不可少的。