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Widespread acquisition of antimicrobial resistance among Campylobacter isolates from UK retail poultry and evidence for clonal expansion of resistant lineages.

Wimalarathna HM, Richardson JF, Lawson AJ, Elson R, Meldrum R, Little CL, Maiden MC, McCarthy ND, Sheppard SK - BMC Microbiol. (2013)

Bottom Line: This was compared with a phylogeny for these isolates based upon Multi Locus Sequence Typing (MLST) to investigate the pattern of antimicrobial resistance acquisition.Erythromycin resistance was associated with Campylobacter coli.These results are consistent with the widespread acquisition of antimicrobial resistance among chicken associated Campylobacter isolates, either through mutation or horizontal gene transfer, and the expansion of these lineages as a proportion of the population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.

ABSTRACT

Background: Antimicrobial resistance is increasing among clinical Campylobacter cases and is common among isolates from other sources, specifically retail poultry - a major source of human infection. In this study the antimicrobial susceptibility of isolates from a UK-wide survey of Campylobacter in retail poultry in 2001 and 2004-5 was investigated. The occurrence of phenotypes resistant to tetracycline, quinolones (ciprofloxacin and naladixic acid), erythromycin, chloramphenicol and aminoglycosides was quantified. This was compared with a phylogeny for these isolates based upon Multi Locus Sequence Typing (MLST) to investigate the pattern of antimicrobial resistance acquisition.

Results: Antimicrobial resistance was present in all lineage clusters, but statistical testing showed a non-random distribution. Erythromycin resistance was associated with Campylobacter coli. For all antimicrobials tested, resistant isolates were distributed among relatively distant lineages indicative of widespread acquisition. There was also evidence of clustering of resistance phenotypes within lineages; indicative of local expansion of resistant strains.

Conclusions: These results are consistent with the widespread acquisition of antimicrobial resistance among chicken associated Campylobacter isolates, either through mutation or horizontal gene transfer, and the expansion of these lineages as a proportion of the population. As Campylobacter are not known to multiply outside of the host and long-term carriage in humans is extremely infrequent in industrialized countries, the most likely location for the proliferation of resistant lineages is in farmed chickens.

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ClonalFrame genealogies of Campylobacter isolates from UK retail poultry surveys in 2001 and 2004–5. Grey-scale shading indicates the percentage of isolates in each ST with antimicrobial resistance to (A) tetracycline, (B) quinolones - naladixic acid & ciprofloxacin combined, (C) erythromycin, (D) chloramphenicol, (E) aminoglycosides. The scale bar indicates the genetic distance in coalescent units.
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Figure 2: ClonalFrame genealogies of Campylobacter isolates from UK retail poultry surveys in 2001 and 2004–5. Grey-scale shading indicates the percentage of isolates in each ST with antimicrobial resistance to (A) tetracycline, (B) quinolones - naladixic acid & ciprofloxacin combined, (C) erythromycin, (D) chloramphenicol, (E) aminoglycosides. The scale bar indicates the genetic distance in coalescent units.

Mentions: The genealogy estimated using ClonalFrame, applied to MLST data, showed a high degree of genetic structuring among retail poultry isolates (Figure 2), with many of the lineages frequently identified from clinical samples being represented. Isolate clustering on the tree correlated with previously identified clonal complex designations (Table 1). For four (tetracycline, quinolones, chloramphenicol & erythromycin) out of the five antimicrobial substances tested in this study, resistance phenotypes were dispersed throughout clusters of related lineages (Table 1). Nearly all isolates tested were sensitive to aminoglycosides, therefore this class of antimicrobial agent was excluded from further analyses.


Widespread acquisition of antimicrobial resistance among Campylobacter isolates from UK retail poultry and evidence for clonal expansion of resistant lineages.

Wimalarathna HM, Richardson JF, Lawson AJ, Elson R, Meldrum R, Little CL, Maiden MC, McCarthy ND, Sheppard SK - BMC Microbiol. (2013)

ClonalFrame genealogies of Campylobacter isolates from UK retail poultry surveys in 2001 and 2004–5. Grey-scale shading indicates the percentage of isolates in each ST with antimicrobial resistance to (A) tetracycline, (B) quinolones - naladixic acid & ciprofloxacin combined, (C) erythromycin, (D) chloramphenicol, (E) aminoglycosides. The scale bar indicates the genetic distance in coalescent units.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3717071&req=5

Figure 2: ClonalFrame genealogies of Campylobacter isolates from UK retail poultry surveys in 2001 and 2004–5. Grey-scale shading indicates the percentage of isolates in each ST with antimicrobial resistance to (A) tetracycline, (B) quinolones - naladixic acid & ciprofloxacin combined, (C) erythromycin, (D) chloramphenicol, (E) aminoglycosides. The scale bar indicates the genetic distance in coalescent units.
Mentions: The genealogy estimated using ClonalFrame, applied to MLST data, showed a high degree of genetic structuring among retail poultry isolates (Figure 2), with many of the lineages frequently identified from clinical samples being represented. Isolate clustering on the tree correlated with previously identified clonal complex designations (Table 1). For four (tetracycline, quinolones, chloramphenicol & erythromycin) out of the five antimicrobial substances tested in this study, resistance phenotypes were dispersed throughout clusters of related lineages (Table 1). Nearly all isolates tested were sensitive to aminoglycosides, therefore this class of antimicrobial agent was excluded from further analyses.

Bottom Line: This was compared with a phylogeny for these isolates based upon Multi Locus Sequence Typing (MLST) to investigate the pattern of antimicrobial resistance acquisition.Erythromycin resistance was associated with Campylobacter coli.These results are consistent with the widespread acquisition of antimicrobial resistance among chicken associated Campylobacter isolates, either through mutation or horizontal gene transfer, and the expansion of these lineages as a proportion of the population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.

ABSTRACT

Background: Antimicrobial resistance is increasing among clinical Campylobacter cases and is common among isolates from other sources, specifically retail poultry - a major source of human infection. In this study the antimicrobial susceptibility of isolates from a UK-wide survey of Campylobacter in retail poultry in 2001 and 2004-5 was investigated. The occurrence of phenotypes resistant to tetracycline, quinolones (ciprofloxacin and naladixic acid), erythromycin, chloramphenicol and aminoglycosides was quantified. This was compared with a phylogeny for these isolates based upon Multi Locus Sequence Typing (MLST) to investigate the pattern of antimicrobial resistance acquisition.

Results: Antimicrobial resistance was present in all lineage clusters, but statistical testing showed a non-random distribution. Erythromycin resistance was associated with Campylobacter coli. For all antimicrobials tested, resistant isolates were distributed among relatively distant lineages indicative of widespread acquisition. There was also evidence of clustering of resistance phenotypes within lineages; indicative of local expansion of resistant strains.

Conclusions: These results are consistent with the widespread acquisition of antimicrobial resistance among chicken associated Campylobacter isolates, either through mutation or horizontal gene transfer, and the expansion of these lineages as a proportion of the population. As Campylobacter are not known to multiply outside of the host and long-term carriage in humans is extremely infrequent in industrialized countries, the most likely location for the proliferation of resistant lineages is in farmed chickens.

Show MeSH
Related in: MedlinePlus