Limits...
The contribution of Escherichia coli from human and animal sources to the integron gene pool in coastal waters.

Moura A, Araújo S, Alves MS, Henriques I, Pereira A, Correia AC - Front Microbiol (2014)

Bottom Line: Common arrays were found among strains from different sources.In 20% (15/76) of strains, integrons were successfully mobilized through conjugation to E. coli CV601.Results obtained support the existence of a diverse integron pool in the E. coli strains from this coastal environment, associated with different resistance traits and plasmid incompatibility groups, mainly shaped by animal fecal pollution inputs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and CESAM, University of Aveiro Aveiro, Portugal.

ABSTRACT
To understand the contribution of animal- and human-derived fecal pollution sources in shaping integron prevalence and diversity in beach waters, 414 Escherichia coli strains were collected from beach waters (BW, n = 166), seagull feces (SF, n = 179), and wastewaters (WW, n = 69), on the World Biosphere Reserve of the Berlenga Island, Portugal. Statistical differences were found between the prevalence of integrons in BW (21%) and WW (10%), but not between BW and SF (19%). The majority of integrase-positive (intI (+))-strains affiliated to commensal phylogroups B1 (37%), A0 (24%), and A1 (20%). Eighteen different gene cassette arrays were detected, most of them coding for resistances to aminoglycosides, trimethoprim, chloramphenicol, and quaternary ammonia compounds. Common arrays were found among strains from different sources. Multi-resistance to three or more different classes of antibiotics was observed in 89, 82, and 57% of intI (+)-strains from BW, SF and WW, respectively. Plasmids were detected in 79% of strains (60/76) revealing a high diversity of replicons in all sources, mostly belonging to IncF (Frep, FIA, and FIB subgroups), IncI1, IncN, IncY, and IncK incompatibility groups. In 20% (15/76) of strains, integrons were successfully mobilized through conjugation to E. coli CV601. Results obtained support the existence of a diverse integron pool in the E. coli strains from this coastal environment, associated with different resistance traits and plasmid incompatibility groups, mainly shaped by animal fecal pollution inputs. These findings underscore the role of wild life in dissemination of integrons and antibiotic resistance traits in natural environments.

No MeSH data available.


Related in: MedlinePlus

Prevalence of replicon types detected in intI+-E. coli among different sources (A) and phylogroups (B). Abbreviations: n.d., not detected; n.s., not statistically significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4129628&req=5

Figure 3: Prevalence of replicon types detected in intI+-E. coli among different sources (A) and phylogroups (B). Abbreviations: n.d., not detected; n.s., not statistically significant.

Mentions: Similar to previous reports on plasmid diversity among intI+-strains (Moura et al., 2012a), a wide and diverse plasmid pool was present in these E. coli (Figure 3A). Replicons were detected in 80% (60/76) of strains (Figure 3A; Table 2), though differences among BW, SF, and WW were not statistically significant. Replicons detected belonged to IncF (Frep, FIA, and FIB subgroups), IncI1, IncN, IncY, and IncK incompatibility groups. More than one replicon type was detected in 41% (31/76) of strains. In strains from phylogroups A0 and B1, up to 5 different replicon types were detected (Figure 3B). Integrons were successfully mobilized through IncF (Frep and FIB subgroups) and IncI1 conjugative plasmids into E. coli CV601 in 20% (15/76) of strains, using streptomycin as selective marker. The majority of intI-transconjugants displayed the resistance patterns observed in donor strains (Table 2), highlighting the importance of co-selection in the spread of multi-resistance traits through horizontal gene transfer. Plasmid DNA from transconjugants showed different restriction patterns (data not shown), including in transconjugants from donors that shared identical integron structures. These results may be explained by the presence of identical integron platforms in different plasmids. Nevertheless, the co-mobilization of multiple plasmids and/or the occurrence of genetic rearrangements in transconjugants resulting in different restriction patterns cannot be excluded. It is also noteworthy that plasmid prevalence and diversity, as well as their transfer ability may be, however, under-estimated due to biases introduced by the technical approaches. Alkaline extraction of plasmid DNA may affect the efficiency to recover larger plasmids, and the mating conditions used may favor the transfer the plasmids of IncF and IncI complexes, which are liquid maters.


The contribution of Escherichia coli from human and animal sources to the integron gene pool in coastal waters.

Moura A, Araújo S, Alves MS, Henriques I, Pereira A, Correia AC - Front Microbiol (2014)

Prevalence of replicon types detected in intI+-E. coli among different sources (A) and phylogroups (B). Abbreviations: n.d., not detected; n.s., not statistically significant.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129628&req=5

Figure 3: Prevalence of replicon types detected in intI+-E. coli among different sources (A) and phylogroups (B). Abbreviations: n.d., not detected; n.s., not statistically significant.
Mentions: Similar to previous reports on plasmid diversity among intI+-strains (Moura et al., 2012a), a wide and diverse plasmid pool was present in these E. coli (Figure 3A). Replicons were detected in 80% (60/76) of strains (Figure 3A; Table 2), though differences among BW, SF, and WW were not statistically significant. Replicons detected belonged to IncF (Frep, FIA, and FIB subgroups), IncI1, IncN, IncY, and IncK incompatibility groups. More than one replicon type was detected in 41% (31/76) of strains. In strains from phylogroups A0 and B1, up to 5 different replicon types were detected (Figure 3B). Integrons were successfully mobilized through IncF (Frep and FIB subgroups) and IncI1 conjugative plasmids into E. coli CV601 in 20% (15/76) of strains, using streptomycin as selective marker. The majority of intI-transconjugants displayed the resistance patterns observed in donor strains (Table 2), highlighting the importance of co-selection in the spread of multi-resistance traits through horizontal gene transfer. Plasmid DNA from transconjugants showed different restriction patterns (data not shown), including in transconjugants from donors that shared identical integron structures. These results may be explained by the presence of identical integron platforms in different plasmids. Nevertheless, the co-mobilization of multiple plasmids and/or the occurrence of genetic rearrangements in transconjugants resulting in different restriction patterns cannot be excluded. It is also noteworthy that plasmid prevalence and diversity, as well as their transfer ability may be, however, under-estimated due to biases introduced by the technical approaches. Alkaline extraction of plasmid DNA may affect the efficiency to recover larger plasmids, and the mating conditions used may favor the transfer the plasmids of IncF and IncI complexes, which are liquid maters.

Bottom Line: Common arrays were found among strains from different sources.In 20% (15/76) of strains, integrons were successfully mobilized through conjugation to E. coli CV601.Results obtained support the existence of a diverse integron pool in the E. coli strains from this coastal environment, associated with different resistance traits and plasmid incompatibility groups, mainly shaped by animal fecal pollution inputs.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology and CESAM, University of Aveiro Aveiro, Portugal.

ABSTRACT
To understand the contribution of animal- and human-derived fecal pollution sources in shaping integron prevalence and diversity in beach waters, 414 Escherichia coli strains were collected from beach waters (BW, n = 166), seagull feces (SF, n = 179), and wastewaters (WW, n = 69), on the World Biosphere Reserve of the Berlenga Island, Portugal. Statistical differences were found between the prevalence of integrons in BW (21%) and WW (10%), but not between BW and SF (19%). The majority of integrase-positive (intI (+))-strains affiliated to commensal phylogroups B1 (37%), A0 (24%), and A1 (20%). Eighteen different gene cassette arrays were detected, most of them coding for resistances to aminoglycosides, trimethoprim, chloramphenicol, and quaternary ammonia compounds. Common arrays were found among strains from different sources. Multi-resistance to three or more different classes of antibiotics was observed in 89, 82, and 57% of intI (+)-strains from BW, SF and WW, respectively. Plasmids were detected in 79% of strains (60/76) revealing a high diversity of replicons in all sources, mostly belonging to IncF (Frep, FIA, and FIB subgroups), IncI1, IncN, IncY, and IncK incompatibility groups. In 20% (15/76) of strains, integrons were successfully mobilized through conjugation to E. coli CV601. Results obtained support the existence of a diverse integron pool in the E. coli strains from this coastal environment, associated with different resistance traits and plasmid incompatibility groups, mainly shaped by animal fecal pollution inputs. These findings underscore the role of wild life in dissemination of integrons and antibiotic resistance traits in natural environments.

No MeSH data available.


Related in: MedlinePlus