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UID:1103@biotech.technion.ac.il
DTSTART;TZID=Asia/Jerusalem:20230503T020000
DTEND;TZID=Asia/Jerusalem:20230503T030000
DTSTAMP:20230504T093900Z
URL:https://biotech.technion.ac.il/events/the-occurrence-and-evolution-of-
 antibiotic-resistomes-in-soils-and-on-plants/
SUMMARY:The occurrence and evolution of antibiotic resistomes in soils and 
 on plants
DESCRIPTION:In natural environments\, antibiotics are often present at sub-
 inhibitory concentrations. Antibiotic resistance genes (ARGs) may have ini
 tially evolved for environmental adaptation rather than resistance to clin
 ically relevant antibiotics. The assembly of a resistome\, which is the co
 llection of all ARGs\, within a developing microbial community remains poo
 rly understood. Germfree models with low initial bacterial loads can unvei
 l bacterial colonization and resistance development under an antibiotic pr
 essure. Our studies aimed to address the following questions: (1) What are
  the key ARGs in soil and plant resistomes\, and what are the core bacteri
 al families\, whether hosting ARGs or not? (2) How do initial bacterial lo
 ads and/or an antibiotic treatment influence the evolution of soil’s and
  plant’s microbiomes and resistomes? (3) How does the plant resistome af
 fect the antibiotic resistance of the foodborne pathogen Salmonella Typhim
 urium? (4) How does the resistome develop and look like in the pristine ca
 ve\, which represents an environment with less human interventions in plan
 etary history?\nSoils with varying initial bacterial loads were initially 
 exposed to a non-germfree environment and treated with different concentra
 tions of tetracycline (TET). Both germfree soil and TET treatments altered
  bacterial community and resistome profiles compared with untreated natura
 l soil. Multidrug resistance (MDR) genes\, especially multidrug efflux pum
 ps\, along with their primary host Burkholderiaceae\, were dominant in the
  development of soil resistomes\, rather than enhancing TET-related ARGs. 
 Next\, we inoculated S. Typhimurium onto lettuce with germfree or natural 
 leaves and grew them in germfree and natural soil\, respectively\, under v
 arious TET treatments. Only germfree soil affected the bacterial community
  and resistome profiles\, with leaves not serving as a site for Salmonella
  resistance development. MDR genes\, particularly multidrug efflux pumps\,
  and their primary host Burkholderiaceae\, remained the key factors in res
 istome development in lettuce roots and soils. Lastly\, we profiled bacter
 ial communities and resistomes in 47 publicly available datasets of 14 pri
 stine cave environments. Microhabitats (sediments\, microbial mats\, water
 \, biofilms\, and minerals) in different environmental conditions led to d
 istinct microbiome profiles. MDR genes\, especially multidrug efflux pumps
 \, and their bacterial hosts were highly prevalent and abundant. Variation
 s in multidrug efflux pumps primarily accounted for significant difference
 s in resistomes between microhabitats. This study represents a pioneering 
 investigation into resistome assemblies within germfree soil and lettuce m
 odels\, underscoring the significance of germfree models for resistome res
 earch. The findings emphasize the need to explore the inherent multidrug e
 fflux pumps with their versatile capabilities\, given that TET selections 
 did not necessarily select for clinically relevant ARGs\, and also may exp
 lain that the prevalence of mobile efflux pumps has been on the rise recen
 tly. Lastly\, the analysis of resistomes in unspoiled cave environments re
 inforces the notion that resistomes originally emerged as a consequence of
  bacterial adaptation to their surroundings.
CATEGORIES:סמינרים
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