Seasonal and spatial distribution of antibiotic resistance in marine microbial communities along a trophic gradient in central Adriatic Sea

doctoral thesis

• Title (croatian): Sezonska i prostorna raspodjela rezistencije na antibiotike u morskim mikrobnim zajednicama duž trofičkog gradijenta u srednjem Jadranu
• Author: Mia Dželalija
• Mentor: Ana Maravić (mentor)
• Committee member: Martina Šeruga Musić (predsjednik povjerenstva)
• Committee member: Mirna Mrkonjić Fuka (član povjerenstva)
• Committee member: Ana Bielen (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2024-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 57 - Biological sciences. Physical anthropology. Biodiversity

Abstract

Marine and ocean environments are the most widespread habitats in the world but are still among the least studied from the aspect of antibiotic resistance (AR). The aim was to investigate the seasonal and spatial features of AR in microbial communities along trophic gradient of central Adriatic encompassing a 68-km transect from wastewater-impacted estuary to coastal and pristine open sea. Eighty microbiomes were profiled by using Illumina-based 16S rRNA amplicon sequencing revealing that biogeographical shifts in microbial community are largely driven by the seasonality, featured by thermohaline stratification and nutrients in particular. Proteobacteria were the predominant along the gradient and major contributors to the marine resistomes. Targeted resistance genes were quantified using RT-qPCR, among which distribution of tetA, blaCTX-M and blaTEM correlated with higher temperature, nutrient load and lower salinity. WHO 'high' and 'critical priority' pathogens including vancomycin-resistant Enterococcus faecium and carbapenemase-producing Enterobacteriaceae were isolated from wastewater-impacted coastal waters, pointing to their sewage-driven dissemination in marine environment. Enterobacteriaceae carried carbapenemase genes (blaKPC-2, blaOXA-48 and blaVIM-
1) on diverse conjugative plasmids favouring their horizontal spread as revealed by conjugation experiments and de novo plasmid sequencing. These results show a complex pattern of AR persisting along the trophic gradient and an importance of anthropogenic influence on its dissemination in marine ecosystems, accentuating the imperative for comprehensive strategies congruent with the One Health paradigm to combat AR in the environment.

Abstract (croatian)

Mora i oceani su najrasprostranjeniji prirodni ekosustavi na Zemlji, a ipak su među najmanje istraženima s aspekta antibiotske rezistencije (AR). Cilj je bio istražiti sezonske i prostorne značajke AR u mikrobnim zajednicama duž trofičkog gradijenta srednjeg Jadrana duž 68 km od estuarija pod utjecajem otpadnih voda do obalnog i otvorenog mora. Osamdeset mikrobioma profilirano je korištenjem 16S rRNA sekvenciranja, otkrivajući da su biogeografski pomaci u mikrobnoj zajednici uvelike potaknuti sezonskim promjenama, osobito termohalinom stratifikacijom i hranjivim tvarima. Proteobakterije su prevladavale duž gradijenta i bile glavni čimbenici morskog rezistoma. Ciljani geni AR kvantificirani su pomoću RT-qPCR, pri čemu je distribucija tetA, blaCTX-M i blaTEM korelirala sa višom temperaturom, povećanom koncentracijom hranjivih tvari i nižim salinitetom. Patogeni 'visokog' i 'kritičnog prioriteta', uključujući vankomicin-rezistentni Enterococcus faecium i karbapenemaze-producirajuće Enterobacteriaceae izolirani su iz obalnog područja pod utjecajem otpadnih voda, što ukazuje na njihovo širenje u morskom okolišu putem kanalizacije. Izolati enterobakterija nosili su karbapenemaza-kodirajuće gene (blaKPC-2, blaOXA-48 and blaVIM-1) na različitim konjugacijskim plazmidima što pogoduje njihovom horizontalnom širenju, a što je potvrđeno eksperimentima konjugacije i de novo sekvenciranjem plazmida. Ovi rezultati pokazuju složeni obrazac AR duž trofičkog gradijenta i važnost antropogenog utjecaja za njezino širenje u morskim ekosustavima te nužnost sveobuhvatnih strategija usklađenih s paradigmom „Jednog zdravlja“ (eng. One health) radi rješavanja problema AR u okolišu.

• Keywords: amplicon sequencing; carbapenemase-producing Enterobacteriacae; environmental factors; marine environment; microbiome; resistome; VREfm; qPCR
• Keywords (croatian): karbapenem-producirajuće Enterobacteriaceae; morski okoliš; mikrobiom; okolišni čimbenici; rezistom; sekvenciranje amplikona; VREfm
• Language: english
• URN:NBN: urn:nbn:hr:217:788157
• Promotion: 2024
• Project: Number: UIP-2019-04-9778; Title: Sezonska i prostorna raspodjela gena rezistencije na antibiotike u morskim mikrobnim zajednicama duž trofičkog gradijenta u srednjem Jadranu; Title: Seasonal and spatial distribution of antibiotic resistance genes in marine microbial communities along a trophic gradient in central Adriatic Sea; Acronym: ARGAS; Leader: Ana Maravić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Installation Research Projects
• Study programme: Title: Doctoral study; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti u području prirodnih znanosti (doktor/doktorica znanosti u području prirodnih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-09-03 10:28:22