Tracing Acinetobacter baumannii’s Journey from Hospitals to Aquatic Ecosystems

• Published in: Microorganisms (Basel) 2024-08, Vol.12 (8), p.1703
• Main Authors: Gheorghe-Barbu, Irina, Dragomir, Rares-Ionut, Gradisteanu Pircalabioru, Gratiela, Surleac, Marius, Dinu, Iulia Adelina, Gaboreanu, Madalina Diana, Czobor Barbu, Ilda
• Format: Article
• Language: English
• Subjects: Acinetobacter baumannii; Amides; Aminoglycosides; Antibacterial agents; Antibiotic resistance; Antibiotics; Aquatic ecosystems; Aquatic environment; Contamination; Drug resistance; Drug resistance in microorganisms; Environmental management; Fecal coliforms; Fluoroquinolones; Gene sequencing; Health risks; Hospitals; Infectious diseases; Management; Medical wastes; Metagenomics; Microbial contamination; Microbiota; Microorganisms; Nosocomial infections; pangenome analysis; Phenotypes; Phosphorus removal; Phylogeny; Pollutants; Public health; resistant Acinetobacter baumannii isolates; RNA; rRNA 16S; Sludge; southern Romanian cities; Sulbactam; Surface water; surface water microbiome; Tetracycline; Tetracyclines; Waste management; wastewater and surface water microbial load; Water; Water monitoring; Water quality; Water quality management; Water treatment; Whole genome sequencing; β-Lactam antibiotics
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms12081703

Background: This study provides a comprehensive analysis of Acinetobacter baumannii in aquatic environments and fish microbiota by integrating culture-dependent methods, 16S metagenomics, and antibiotic resistance profiling. Methods: A total of 83 A. baumannii isolates were recovered using culture-dependent methods from intra-hospital infections (IHI) and wastewater (WW) and surface water (SW) samples from two southern Romanian cities in August 2022. The antibiotic susceptibility was screened using disc diffusion, microdilution, PCR, and Whole Genome Sequencing assays. Results: The highest microbial load in the analyzed samples was found in Glina, Bucharest, for both WW and SW samples across all investigated phenotypes. For Bucharest isolates, the resistance levels corresponded to fluoroquinolones > aminoglycosides > β-lactam antibiotics. In contrast, A. baumannii from upstream SW samples in Târgoviște showed the highest resistance to aminoglycosides. The bla [sub.OXA-23] gene was frequently detected in IHI, WW, and SW isolates in Bucharest, but was absent in Târgoviște. Molecular phylogeny revealed the presence of ST10 in Târgoviște isolates and ST2 in Bucharest isolates, while other minor STs were not specifically correlated with a sampling point. Using 16S rRNA sequencing, significant differences in microbial populations between the two locations was identified. The low abundance of Alphaproteobacteria and Actinobacteria in both locations suggests environmental pressures or contamination events. Conclusions: These findings indicate significant fecal contamination and potential public health risks, emphasizing the need for improved water quality monitoring and management.