Occupational Exposure and Carriage of Antimicrobial Resistance Genes (tetW, ermB) in Pig Slaughterhouse Workers

Abstract

Objectives Slaughterhouse staff is occupationally exposed to antimicrobial resistant bacteria. Studies reported high antimicrobial resistance gene (ARG) abundances in slaughter pigs. This cross-sectional study investigated occupational exposure to tetracycline (tetW) and macrolide (ermB) resistance genes and assessed determinants for faecal tetW and ermB carriage among pig slaughterhouse workers. Methods During 2015–2016, 483 faecal samples and personal questionnaires were collected from workers in a Dutch pig abattoir, together with 60 pig faecal samples. Human dermal and respiratory exposure was assessed by examining 198 carcass, 326 gloves, and 33 air samples along the line, next to 198 packed pork chops to indicate potential consumer exposure. Samples were analyzed by qPCR (tetW, ermB). A job exposure matrix was created by calculating the percentage of tetW and ermB positive carcasses or gloves for each job position. Multiple linear regression models were used to link exposure to tetW and ermB carriage. Results Workers are exposed to tetracycline and macrolide resistance genes along the slaughter line. Tetw and ermB gradients were found for carcasses, gloves, and air filters. One packed pork chop contained tetW, ermB was non-detectable. Human faecal tetW and ermB concentrations were lower than in pig faeces. Associations were found between occupational tetW exposure and human faecal tetW carriage, yet, not after model adjustments. Sampling round, nationality, and smoking were determinants for ARG carriage. Conclusion We demonstrated clear environmental tetracycline and macrolide resistance gene exposure gradients along the slaughter line. No robust link was found between ARG exposure and human faecal ARG carriage.

Risk Factors for Antimicrobial Resistance in Turkey Farms: A Cross-Sectional Study in Three European Countries

“…A qPCR assay was performed as previously described [ermB, tetW, 16S rRNA [42]; sul2 and aph3 -III [19]]. Briefly, all samples were run in two technical PCR duplicates with a non-competitive internal amplification control (IAC) to control quality.…”

Evaluation of Antibiotic Resistance in Bacterial Strains Isolated from Sewage of Slaughterhouses Located in Sicily (Italy)

“…Many slaughtering activities are sources of contamination and release of microorganisms into the slaughter environment, among which defeathering and evisceration are considered the most important ones, mainly due to the discharge of intestinal content that occurs during these activities [ 36 , 37 ]. Especially for poultry slaughterhouses, previous studies have highlighted that the highest bacterial load is present in the first step of the entire process, the “hanging of poultry”, and then decreases during the defeathering process, before increasing again after evisceration.…”

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

“…Contamination of water, machinery and workers’ hands and their tools may introduce/spread ARB on the line (Gomes‐Neves et al., 2012). Some points, principally scalding and singeing, could be potential critical control points (CCP) to reduce the burden of ARB (Wu et al., 2009; Van Gompel et al., 2020). Other points such as carcass polishing and splitting can result in cross‐contamination between slaughter batches (Gomes‐Neves et al., 2012; Melero et al., 2012).…”

“…In addition to culture‐based studies, there are some studies evaluating occupational exposure to ARGs such as tet W or ermB which confer resistance to tetracycline and macrolides respectively (Van Gompel et al., 2020). Both genes and antimicrobial classes are among the most abundant in pig faecal resistomes (Munk et al., 2018).…”

“…In contrast, other studies state that the transmission through air in slaughter facilities could be negligible (Pearce et al., 2006; Okraszewska‐Lasica et al., 2014) although another study has demonstrated that filtered air reduces carcass contamination, but also highlights that other factors (such as carcass handling or processing) have more impact in bacterial surface contamination (Burfoot et al., 2006). Occupational transmission of AMR may occur at slaughterhouses (Mulders et al., 2010; van Cleef et al., 2010; Gilbert et al., 2012; Van Gompel et al., 2020) and at the same time workers, through their hands or equipment, may act as sources of AMR (Van Gompel et al., 2020). Resistome studies reveal variations in ARGs along the slaughter line and further emphasise the importance of good hygiene in carcass processing (Campos Calero et al., 2018; Van Gompel et al., 2020).…”