Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2021
Publication Date: 5/11/2021
Citation: Agga, G.E., Silva, P.J., Martin, R.S. 2021. Detection of extended-spectrum beta-lactamase-producing and carbapenem-resistant bacteria from mink feces and feed in the United States. Foodborne Pathogens and Disease. 18(7): 497-505. https://doi.org/10.1089/fpd.2020.2898.
Interpretive Summary: Extended spectrum beta-lacatmase enzymes inactivate broad spectrum cephalosporins that are the drugs of choice to treat severe bacterial infections such as salmonellosis. Carbapenems are the last resort antibiotics for the treatment of live threatening infections. However, resistant to carbapenems is also increasing because of their increased use due to increased bacterial resistance to the extended spectrum cephalosporins. The U.S. Centers for Disease Control (CDC) considers carbapenem resistant bacteria and extended spectrum beta-lactamase producing bacteria as urgent and serious public health threats, respectively. The United States monitors antimicrobial resistant bacteria in humans, food animals and retail meat. The U.S. is one of the leading mink producers in the world. Concentrated mink production can be a reservoir for antibiotic resistant bacteria that can escape the production farms and spread to the environment which may eventually reach people through contaminated water and vegetables when mink manure is land applied. We investigated the level of extended spectrum beta-lactamase producing and carbapenem resistant bacteria in the fecal and feed samples obtained from a mink farm. Although diverse extended spectrum beta-lactamse producing bacteria were identified, Escherichia coli and Klebsiella pneumoniae were the two most frequently isolated bacteria both from the fecal and feed samples. Carbapenem resistant bacteria including the pathogenic ones were detected, although at a lower level. This study indicates the presence of antibiotic resistant bacteria that are deemed serious and urgent threats by the CDC. Antimicrobial resistance monitoring programs can incorporate mink farming in to a one health approach for combating antimicrobial resistance.
Technical Abstract: Antibiotic-resistant infections caused by extended-spectrum b-lactamases (ESBLs) and carbapenemases are increasing worldwide. Bacteria resistant to extended-spectrum cephalosporins and last resort carbapenems have been reported from food animals and their environments. Other concentrated nonfood-producing animals such as mink farming can be a reservoir of bacteria resistant to these critically important antibiotics. The objective of this study was to determine the prevalence of ESBL-producing bacteria and carbapenem-resistant (CR) bacteria from mink fecal (n = 42) and feed (n = 8) samples obtained from a commercial mink farm in the United States. The most prevalent ESBL-producing bacteria identified from the fecal samples were Escherichia coli (93%), Klebsiella pneumoniae (76%), and Proteus species (88%). E. coli (100%) and K. pneumoniae (75%) were also the most prevalent ESBL-producing bacteria identified from feed samples. All ESBL E. coli isolates were resistant to penicillin and most cephem beta-lactam antibiotics. Among the ESBL E. coli isolates, co-resistance was observed to ciprofloxacin (33%) and gentamicin (28%) indicating multidrug resistance. ESBL E. coli isolates predominantly carried blaCTX-M-14 and blaCTX-M-15 genes. Although all feed K. pneumoniae isolates carried blaCTX-M-9, all fecal K. pneumoniae isolates carried blaSHV. CR Pseudomonas species (7%), Hafnia alvei (24%), and Myroides odoratimimus (9.5%) were detected from fecal samples. H. alvei (37.5%) was the only CR bacteria detected from the feed samples. All CR isolates were polymerase chain reaction negative for the tested carbapenemases that are commonly reported, which may indicate intrinsic rather than acquired resistance. This study indicates that mink production can be a reservoir for bacteria resistant to the highest priority critically important antibiotics for human health.