Purpose: This study compared the antimicrobial resistance of Salmonella isolated from retail beef and beef cattle, at harvest, in Honduras.
Methods: Antimicrobial resistance of Salmonella isolates from beef cattle (n=47) and retail beef (n=30) in Honduras was determined by microbroth dilution. The minimum inhibitory concentrations (MIC) of nine antimicrobial classes were estimated. Values of MIC were obtained using the Sensititre® OptiRead™ system and Sensititre® software SWIN®(V3.3). Results were categorized as resistant, intermediate, or susceptible according to the manufacturer’s instructions.
Results: A total of 86.7% (26/30) of isolates from retail beef were deemed resistant, with 3.3% (1/30) intermediate, and 10.0% (3/30) susceptible to at least one antimicrobial class. Moreover, isolates from beef cattle were 72.3% (34/47) resistant with 8.5% (4/47) intermediate and 19.2% (9/47) susceptible to at least one antimicrobial. Among the resistant isolates from retail beef and beef cattle, 65.4% (17/26) and 41.2% (14/34), respectively, were multidrug resistant. In both cases, resistance to β-lactams was similar (55.6% [15/27] in retail vs 47.4% [18/38]) during harvest. The penicillin resistance rate was significantly different between retail and harvest isolates (59.3% [16/27] vs 23.7 % [9/38]). Furthermore, fluoroquinolone resistance was significantly different with 29.6% (8/27) in retail and 68.4% (26/38) during harvest.
Significance: Contamination of beef products with antimicrobial and multidrug resistant Salmonella may result in foodborne illnesses that are difficult to treat. There is a variation of antimicrobial resistant Salmonella throughout the meat chain, where certain resistances may be mitigated while others may be enhanced. Further investigations are required to understand their origin and implement food protection strategies.