Table 2.

Selected examples of cattle-related AMR human health threats

Source	Bacterial species	Human outbreak	AMR profile	Mechanism	Notes	Study
Calves	S. enterica serotype Typhimurium	Veterinarian’s child	Ampicillin, chloramphenicol, tetracycline, sulfisoxazole, kanamycin, streptomycin, cephalothin, ceftriaxone and ceftiofur, aztreonam, cefoxitin, gentamicin, and tobramycin	Ceftriaxone resistance conferred by bla CMY-2 on a conjugable plasmid	An isolated, domestically acquired case requiring hospitalization. Failure of ampicillin and sulbactam therapy, but recovery with amoxicillin/clavulanate. Direct molecular evidence linking MDR isolates from herds treated by the patient’s father	[216]
Cattle, Sheep	MRSA ST130	Two farmers	Cefoxitin and penicillin	Resistance conferred by mecC (mecA homologue), SCCmec type XI [220]	Direct transfer of mecC-MRSA from cattle and sheep to humans resulting in wound infections	[211]
Veal calves	MRSA ST398	Asymptomatic carriage by farm employees	Methicillin and others	Resistance conferred by mecA, SCCmec not stated	Asymptomatic human MRSA carriage rates associated with prevalence in calves and frequency of animal contact. MRSA carriage in calves associated with antimicrobial use	[217]
Cattle, Swine	E. coli, Salmonella	Potential, sporadic transmission to humans	Ceftriaxone, with high-levels of co-resistance to chloramphenicols, tetracycline, sulfisoxazole, streptomycin, gentamicin, tobramycin, and ciprofloxacin	3rd generation cephalosporin resistance conferred by plasmid-born bla CMY-2	Potential transfer of bla CMY-2 plasmids between E. coli and Salmonella. Close relationship between bla CMY-2 plasmids in E. coli found in bovines and humans	[210]
Ground beef, possibly from dairy cows	S. enterica serotype Typhimurium DT104	Large clustered human outbreak	Ampicillin, chloramphenicol, streptomycin, sulfemethoxazole, and tetracycline (R-type ACSSuT)	MDR genes potentially encoded on Salmonella genomic island 1	Multi-state outbreak, potentially affecting >2200 people. Severe illness, with a high proportion of patients receiving intravenous rehydration and requiring hospitalization	[213]