Abstract Catheter-related urinary tract infections are one of the most common biofilm-associated diseases. Within biofilms, bacteria cooperate, compete, or have neutral interactions. This study aimed to investigate the interactions in polymicrobial biofilms of Klebsiella pneumoniae and Enterococcus faecalis, two of the most common uropathogens. Although K. pneumoniae was the most adherent strain, it could not maintain dominance in the polymicrobial biofilm due to the lactic acid produced by E. faecalis in a glucose-enriched medium. This result was supported by the use of E. faecalis V583 ldh-1/ldh-2 double mutant (non-producer of lactic acid), which did not inhibit the growth of K. pneumoniae. Lyophilized cell-free supernatants obtained from E. faecalis biofilms also showed antimicrobial/anti-biofilm activity against K. pneumoniae. Conversely, there were no significant differences in planktonic polymicrobial cultures. In summary, E. faecalis modifies the pH by lactic acid production in polymicrobial biofilms, which impairs the growth of K. pneumoniae.

中文翻译：

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粪肠球菌在富含葡萄糖的培养基中抑制多微生物生物膜中肺炎克雷伯菌的生长

摘要 导管相关尿路感染是最常见的生物膜相关疾病之一。在生物膜内，细菌合作、竞争或具有中性相互作用。本研究旨在调查肺炎克雷伯菌和粪肠球菌这两种最常见的泌尿系统病原体在多种微生物生物膜中的相互作用。尽管肺炎克雷伯菌是附着力最强的菌株，但由于粪肠球菌在富含葡萄糖的培养基中产生的乳酸，它无法保持在多微生物生物膜中的优势。这一结果得到了使用粪肠球菌 V583 ldh-1/ldh-2 双突变体（非乳酸生产者）的支持，该突变体不抑制肺炎克雷伯菌的生长。从粪肠球菌生物膜获得的冻干无细胞上清液也显示出对肺炎克雷伯菌的抗菌/抗生物膜活性。反过来，在浮游多微生物培养物中没有显着差异。总之，粪肠球菌通过在多微生物生物膜中产生乳酸来改变 pH 值，这会损害肺炎克雷伯菌的生长。