Resistance to antimicrobial agents in campylobacter isolated from chickens raised in intensive and organic farms and its implications for the management of risk to human health

The use of antimicrobials in poultry may lead to the emergence of resistant micro-organisms that could cause additional health risk to humans through food consumption. This study aims to investigate the relative health risks from Campylobacter and its antimicrobial resistance associated with chicken raised in organic and intensive rearing systems. Three groups of chicken were tested, pre-packaged intensively reared (PIC) and pre-packaged organically reared chickens (POC) both purchased from supermarkets and unwrapped intensively reared (BIC) chickens purchased from butcher' shops in London. Thirty chickens were randomly sampled for each group. Campylobacter was isolated using three culture methods and enumerated using most probable number method (MPN). A modified MPN was also developed for the study. Resistance rates to three antimicrobials were determined using an agar dilution method. Numbers and antimicrobial resistance rates of campylobacter were used in consumer risk models to calculate health risks. The BICs harboured significantly highest numbers of Campylobacter (8.0+0.81log₁₀MPN/g), followed by the POCs and PICs. All isolates from all groups of chickens were resistant to erythromycin and nalidixic acid. All isolates from the POCs were susceptible to ciprofioxacin, whereas 8.7% of the PICs and 26.7% of the BICs harboured resistant isolates. The calculated risk of campylobacter associated illness related to the consumption of chicken meals using the dose response relationship model was found to be the highest for the BICs group (33% probability). However, this is the worst case scenario. If elevated internal temperatures (63°C-72°C) are achieved for a sufficient length of time (1-5 minutes), this risk is reduced to <1 %. High resistance rates to antimicrobials may generate additional risk where levels of infection are high. Potential intervention options for the reduction of campylobacter load in chickens and the control of antimicrobial resistance were considered. The most significant factors found were the initial number of organisms, personal hygiene practices and cooking procedures

Tackling antibiotic resistance: the environmental framework

Antibiotic resistance is a threat to human and animal health worldwide, and key measures are required to reduce the risks posed by antibiotic resistance genes that occur in the environment. These measures include the identification of critical points of control, the development of reliable surveillance and risk assessment procedures, and the implementation of technological solutions that can prevent environmental contamination with antibiotic resistant bacteria and genes. In this Opinion article, we discuss the main knowledge gaps, the future research needs and the policy and management options that should be prioritized to tackle antibiotic resistance in the environment

Antimicrobial resistance of campylobacter species isolated from edible bivalve molluscs purchased from Bangkok markets, Thailand.

Campylobacter species have been recognized as the most commonly reported cause of bacterial gastroenteritis in humans. The increase of resistance rates to drugs of choice used for treatment in campylobacteriosis is becoming a public health concern. In parallel, the increased use of antimicrobials in aquaculture may lead to the emergence of resistant microorganisms and is likely to cause additional health risk to humans through food consumption. The study assesses the presence of antimicrobial resistance in Campylobacter species isolated from three groups of bivalve molluscs (bloody cockles, green mussels, and oysters) purchased from markets in Bangkok. Thirty samples were collected from each group. Susceptibility to three antimicrobials was determined using the Epsilometer test. Rates of erythromycin, nalidixic acid, and ciprofloxacin resistance in Campylobacter isolates were 72–84%, 28–40%, and 21–25%, respectively. There was no statistically significant difference in the prevalence of each antimicrobial resistance between the three groups. This study demonstrates a significant level of antimicrobial resistance in the Campylobacter spp. isolated from molluscs with a particular high rate of resistance to erythromycin. Consumption of raw molluscs contaminated with antimicrobial-resistant Campylobacter spp. may therefore result in resistant infections in humans

Resistance to three antimicrobial agents of campylobacter isolated from organically- and intensively-reared chickens purchased from retail outlets

Resistance rates to three antimicrobials (ciprofloxacin, erythromycin and nalidixic acid) in Campylobacter isolated from organically- and intensively-reared chickens purchased from supermarkets and butcher's shops in London were determined. Significant differences in the minimum inhibitory concentrations (MICs) of nalidixic acid were found, with the highest values in unpackaged intensively-reared chickens and the lowest values in organically-reared chickens. Using pre-set breakpoints, all isolates from all groups of chickens were identified as resistant to erythromycin and nalidixic acid. All isolates from the organically-reared group were susceptible to ciprofloxacin. Of the supermarket intensively-reared chickens, 8.7% harboured resistant isolates, all on the external parts, indicating post-slaughtering contamination. The highest percentage (26.7%) was in chickens from butcher shops, mostly in the chicken cavities, suggesting a link to treatment on the farm