A survey of fluoroquinolone resistance inEscherichia coliand thermophilicCampylobacterspp. on poultry and pig farms in Great Britain

Abstract

Aims: To estimate the proportions of farms on which broilers, turkeys and pigs were shedding fluoroquinolone (FQ)‐resistant Escherichia coli or Campylobacter spp. near to slaughter. Methods and Results: Freshly voided faeces were collected on 89 poultry and 108 pig farms and cultured with media containing 1·0 mg l−1 ciprofloxacin. Studies demonstrated the specificity of this sensitive method, and both poultry and pig sampling yielded FQ‐resistant E. coli on 60% of farms. FQ‐resistant Campylobacter spp. were found on around 22% of poultry and 75% of pig farms. The majority of resistant isolates of Campylobacter (89%) and E. coli (96%) tested had minimum inhibitory concentrations for ciprofloxacin of ≥8 mg l−1. The proportion of resistant E. coli and Campylobacter organisms within samples varied widely. Conclusions: FQ resistance is commonly present among two enteric bacterial genera prevalent on pig and poultry farms, although the low proportion of resistant organisms in many cases requires a sensitive detection technique. Significance and Impact of the Study: FQ‐resistant bacteria with zoonotic potential appear to be present on a high proportion of UK pig and poultry farms. The risk this poses to consumers relative to other causes of FQ‐resistant human infections remains to be clarified.

Farm-level risk factors for fluoroquinolone resistance inE. coliand thermophilicCampylobacterspp. on finisher pig farms

“…This was shown in related studies where the resistant proportion of the E. coli population in faeces from pigs on seven affected pig farms ranged between 0.008% and 53% and the resistant proportion of the Campylobacter population on five affected pig farms varied from <10% to 100% [23]. It seems that the greatest scope for avoiding the development of FQ resistance may lie with those farms that have never used FQ, but which on the present evidence appear still to be at substantial risk of acquiring such resistance.…”

Scientific Opinion on an estimation of the public health impact of setting a new target for the reduction ofSalmonellain turkeys

“…A theoretical calculation suggested that a reduction of five pairs to two pairs of boot swabs per flock could have reduced the overall prevalence estimate from 3.8 % to 2.8 %, but this does not take into account the fact that each pair of boot swabs was only used over one-fifth of the area of the house in the baseline survey. Whatever the sampling or culture method chosen, it is always possible to increase detection of infected flocks further by applying more complex or intensive protocols (Carrique-Mas and Davies, 2008;). …”

“…Salmonella normally migrates more quickly than competing organisms in the malachite green/magnesium chloride based inhibitory medium at 41.5 °C and can be preferentially recovered from the margin of the zone of turbid growth. A loop of this growth is plated on to two selective indicator agars, Xylose Lysine Decarboxylase agar (XLD) and a second media of choice, although the value of the second media is often debatable ) and greater detection could normally be achieved by testing more samples with a single plate method (Carrique-Mas and Davies, 2008). Suspect colonies are confirmed biochemically and/or by slide agglutination tests and isolates can then be submitted for serotyping and further characterisation.…”

“…Detection of Salmonella in breeding flocks is improved by the inclusion of a dust sample as well as a faeces sample . Dust can be a valuable sample as most Salmonella strains survive desiccation well compared with competing organisms and dust accumulates over time, so is likely to include faecal components from periods between sampling where levels of Salmonella excretion may have been higher (Carrique-Mas and Davies, 2008). Sensitivity analysis carried out by EFSA (EFSA, 2008b) using data from the baseline survey of breeding flocks showed that in several MSs with positive flocks only one or two pairs of the five pairs of boot swabs that were taken were found to be positive.…”

“…Resistance to extended spectrum cephalosporins in Salmonella has emerged more recently, predominantly in the USA and Canada initially (Gray et al, 2004;Poppe et al, 2006;Poppe et al, 2005;Salmon and Watts, 2000;Sjolund-Karlsson et al, 2010;Taylor et al, 2008). These strains typically possess the bla CMY-2 resistance gene on a transferable multidrug resistance plasmid that can move between different Salmonella serovars and E. coli or other commensal flora (Allen and Poppe, 2002a).…”