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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 antimicrobial resistance in intI+-E. coli strains. Antibiotic abbreviations: AMP, ampicillin; AML, amoxicillin; AMC, amoxicillin + clavulanic acid; PRL, piperacillin; TZP, piperacillin + tazobactam; CEF, cefalothin; CAZ, ceftazidime; CTX, cefotaxime; GEN, gentamicin; STR, streptomycin; IPM, imipenem; NAL, nalidixic acid; CIP, ciprofloxacin; TET, tetracycline; CHL, chloramphenicol; STX, trimethoprim/sulfamethoxazole. Only statistical significant differences are shown: *P < 0.05; **P < 0.01.
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Figure 2: Prevalence of antimicrobial resistance in intI+-E. coli strains. Antibiotic abbreviations: AMP, ampicillin; AML, amoxicillin; AMC, amoxicillin + clavulanic acid; PRL, piperacillin; TZP, piperacillin + tazobactam; CEF, cefalothin; CAZ, ceftazidime; CTX, cefotaxime; GEN, gentamicin; STR, streptomycin; IPM, imipenem; NAL, nalidixic acid; CIP, ciprofloxacin; TET, tetracycline; CHL, chloramphenicol; STX, trimethoprim/sulfamethoxazole. Only statistical significant differences are shown: *P < 0.05; **P < 0.01.

Mentions: Thus, integron structures detected contained genes involved in diverse resistance mechanisms, including enzymatic antibiotic modification (aadA, aadB, aacA, catB, sat, sul), efflux pumps (qacH, qacE) and target protection proteins (qnrS). This diversity of resistance mechanisms largely contributed to the high prevalence of multiresistant intI+-E. coli (64/76, 83%; considering simultaneous resistance to 3 or more different classes of antibiotics), although the presence of additional mechanisms of resistance besides those within integrons cannot be excluded. Prevalence of multi-resistant strains in BW (89%) was statistically different from that observed in WW (57%), but not to the one observed in SF (82%). Overall, the most frequently resistances detected were against tetracycline (87%), streptomycin (79%), ampicillin (70%), amoxicillin (70%), trimethoprim-sulfamethoxazole (70%), piperacillin (53%), and chloramphenicol (45%) (Figure 2). Differences among sources were not statistically significant, except for resistances against amoxicillin+clavulanic acid and imipenem, that were more prevalent in wastewaters (P < 0.01). The prevalence and risk of dissemination of resistant strains to last-resort antibiotics, such as imipenem, is nowadays a matter of great concern, reducing treatment options for infectious diseases. Imipenem resistance if often associated to the presence of integron-borne carbapenemase gene cassetes, such as blaVIM, blaIMP, and blaGES (INTEGRALL database, Moura et al., 2009) and/or plasmid-borne carbapenemases, such as blaKPC, blaOXA−48, and blaNDM−1 (Carattoli, 2013). Nevertheless, none of these mechanisms have been detected in these strains (Alves et al., 2014). Further investigations will allow to elucidate the mechanisms of carbapenem resistance present in these strains as well their potential risk of dissemination into natural environments.


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 antimicrobial resistance in intI+-E. coli strains. Antibiotic abbreviations: AMP, ampicillin; AML, amoxicillin; AMC, amoxicillin + clavulanic acid; PRL, piperacillin; TZP, piperacillin + tazobactam; CEF, cefalothin; CAZ, ceftazidime; CTX, cefotaxime; GEN, gentamicin; STR, streptomycin; IPM, imipenem; NAL, nalidixic acid; CIP, ciprofloxacin; TET, tetracycline; CHL, chloramphenicol; STX, trimethoprim/sulfamethoxazole. Only statistical significant differences are shown: *P < 0.05; **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Prevalence of antimicrobial resistance in intI+-E. coli strains. Antibiotic abbreviations: AMP, ampicillin; AML, amoxicillin; AMC, amoxicillin + clavulanic acid; PRL, piperacillin; TZP, piperacillin + tazobactam; CEF, cefalothin; CAZ, ceftazidime; CTX, cefotaxime; GEN, gentamicin; STR, streptomycin; IPM, imipenem; NAL, nalidixic acid; CIP, ciprofloxacin; TET, tetracycline; CHL, chloramphenicol; STX, trimethoprim/sulfamethoxazole. Only statistical significant differences are shown: *P < 0.05; **P < 0.01.
Mentions: Thus, integron structures detected contained genes involved in diverse resistance mechanisms, including enzymatic antibiotic modification (aadA, aadB, aacA, catB, sat, sul), efflux pumps (qacH, qacE) and target protection proteins (qnrS). This diversity of resistance mechanisms largely contributed to the high prevalence of multiresistant intI+-E. coli (64/76, 83%; considering simultaneous resistance to 3 or more different classes of antibiotics), although the presence of additional mechanisms of resistance besides those within integrons cannot be excluded. Prevalence of multi-resistant strains in BW (89%) was statistically different from that observed in WW (57%), but not to the one observed in SF (82%). Overall, the most frequently resistances detected were against tetracycline (87%), streptomycin (79%), ampicillin (70%), amoxicillin (70%), trimethoprim-sulfamethoxazole (70%), piperacillin (53%), and chloramphenicol (45%) (Figure 2). Differences among sources were not statistically significant, except for resistances against amoxicillin+clavulanic acid and imipenem, that were more prevalent in wastewaters (P < 0.01). The prevalence and risk of dissemination of resistant strains to last-resort antibiotics, such as imipenem, is nowadays a matter of great concern, reducing treatment options for infectious diseases. Imipenem resistance if often associated to the presence of integron-borne carbapenemase gene cassetes, such as blaVIM, blaIMP, and blaGES (INTEGRALL database, Moura et al., 2009) and/or plasmid-borne carbapenemases, such as blaKPC, blaOXA−48, and blaNDM−1 (Carattoli, 2013). Nevertheless, none of these mechanisms have been detected in these strains (Alves et al., 2014). Further investigations will allow to elucidate the mechanisms of carbapenem resistance present in these strains as well their potential risk of dissemination into natural environments.

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