Anti-Klebsiella pneumoniae activity of secondary metabolism of Achromobacter from the intestine of Periplaneta americana

by Selleckchem | Sep 13 2023

Background: Klebsiella pneumoniae is one of the main pathogens of clinical isolation and nosocomial infections, as K. pneumoniae show broad-spectrum resistance to β-lactam and carbapenem antibiotics. It is emerging clinical need for a safe and effective drug to anti-K. pneumoniae. At present, Achromobacter mainly focused on its degradation of petroleum hydrocarbons, polycyclic aromatic hydrocarbons, assisting insects to decompose, degrade heavy metals and utilize organic matter, but there were few reports on the antibacterial activity of the secondary metabolites of Achromobacter.

Results: In this study, a strain WA5-4-31 from the intestinal tract of Periplaneta americana exhibited strong activity against K. Pneumoniae through preliminary screening. The strain was determined to be Achromobacter sp. through the morphological characteristics, genotyping and phylogenetic tree analysis, which is homologous to Achromobacter ruhlandii by 99%, its accession numbe in GenBank at National Center for Biotechnology Information (NCBI) is MN007235, and its deposit number was GDMCC NO.1.2520. Six compounds (Actinomycin D, Actinomycin X2, Collismycin A, Citrinin, Neoechinulin A and Cytochalasin E) were isolated and determined by activity tracking, chemical separation, nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. Among them, Actinomycin D, Actinomycin X2, Collismycin A, Citrinin and Cytochalasin E showed a good effect on anti-K. pneumoniae, with MIC values of 16-64 µg/mL.

Conclusions: The study reported Achromobacter, which was from the intestinal tract of Periplaneta americana with the activity against K. Pneumoniae, can produce antibacterial compounds for the first time. It lays the foundation for development of secondary metabolites of insect intestinal microorganisms.

Comments:

The study conducted screening and isolation of a strain called WA5-4-31 from the intestinal tract of Periplaneta americana (American cockroach), which exhibited strong antibacterial activity against Klebsiella pneumoniae. Through morphological characteristics, genotyping, and phylogenetic tree analysis, the strain was identified as Achromobacter sp. The identified strain was found to be 99% homologous to Achromobacter ruhlandii, with its accession number in GenBank at the National Center for Biotechnology Information (NCBI) being MN007235. Additionally, its deposit number was GDMCC NO.1.2520.

Six compounds, namely Actinomycin D, Actinomycin X2, Collismycin A, Citrinin, Neoechinulin A, and Cytochalasin E, were isolated and identified through activity tracking, chemical separation, nuclear magnetic resonance (NMR), and mass spectrometry (MS) analysis. Among these compounds, Actinomycin D, Actinomycin X2, Collismycin A, Citrinin, and Cytochalasin E exhibited significant antibacterial effects against K. pneumoniae, with minimum inhibitory concentration (MIC) values ranging from 16 to 64 µg/mL.

This study is significant as it reports the antibacterial activity of Achromobacter, specifically from the intestinal tract of the American cockroach, against K. pneumoniae for the first time. It provides a foundation for further exploration and development of secondary metabolites produced by insect intestinal microorganisms for potential therapeutic applications against K. pneumoniae infections.