PDF(Pubmed)
Abstract：
Neonatal sepsis leads to severe morbidity and occasionally death among neonates within the first week following birth, particularly in low- and middle-income countries. Empirical therapy includes antibiotics recommended by WHO. However, these have been ineffective against antimicrobial multidrug-resistant bacterial strains such as Klebsiella spp, Escherichia coli, and Staphylococcus aureus species. To counter this problem, new molecules and alternative sources of compounds with antibacterial activity are sought as options. Actinobacteria, particularly pathogenic strains, have revealed a biotechnological potential still underexplored. This study aimed to determine the presence of biosynthetic gene clusters and the antimicrobial activity of actinobacterial strains isolated from clinical cases against multidrug-resistant bacteria implicated in neonatal sepsis. In total, 15 strains isolated from clinical cases of actinomycetoma were used. PCR screening for the PKS-I, PKS-II, NRPS-I, and NRPS-II biosynthetic systems determined their secondary metabolite-producing potential. The strains were subsequently assayed for antimicrobial activity by the perpendicular cross streak method against Escherichia fergusonii Sec 23, Klebsiella pneumoniae subsp. pneumoniae H1064, Klebsiella variicola H776, Klebsiella oxytoca H793, and Klebsiella pneumoniae subsp. ozaenae H7595, previously classified as multidrug-resistant. Finally, the strains were identified by 16S rRNA gene sequence analysis. It was found that 100% of the actinobacteria had biosynthetic systems. The most frequent biosynthetic system was NRPS-I (100%), and the most frequent combination was NRPS-I and PKS-II (27%). All 15 strains showed antimicrobial activity. The strain with the highest antimicrobial activity was Streptomyces albus 94.1572, as it inhibited the growth of the five multidrug-resistant bacteria evaluated.
摘要：
新生儿败血症在出生后的第一周内导致严重的发病率和偶尔死亡。特别是在低收入和中等收入国家。经验性治疗包括WHO推荐的抗生素。然而,这些对抗菌多药耐药菌株，如克雷伯菌属，大肠杆菌,和金黄色葡萄球菌。为了解决这个问题，寻求具有抗菌活性的新分子和化合物的替代来源作为选择。放线菌,特别是致病菌株，揭示了生物技术潜力仍未得到充分开发。这项研究旨在确定生物合成基因簇的存在以及从临床病例中分离出的针对与新生儿败血症有关的多药耐药细菌的放线菌菌株的抗菌活性。总的来说,使用了从放线菌瘤临床病例中分离的15株菌株。PCR筛选PKS-I，PKS-II,NRPS-I,和NRPS-II生物合成系统决定了它们产生次级代谢产物的潜力。随后通过垂直横纹法对菌株进行了抗肺炎克雷伯菌亚种FergusoniiSec23的抗微生物活性测定。肺炎克雷伯菌H1064，花色克雷伯菌H776，氧化克雷伯菌H793和肺炎克雷伯菌亚种。ozaenaeH7595，以前被归类为多药耐药。最后,通过16SrRNA基因序列分析对菌株进行鉴定。发现100%的放线菌具有生物合成系统。最常见的生物合成系统是NRPS-I（100％），最常见的组合是NRPS-I和PKS-II（27％）。所有15个菌株均显示出抗微生物活性。具有最高抗菌活性的菌株是白链霉菌94.1572，因为它抑制了所评估的5种多重耐药细菌的生长。
