Characterization of antimicrobial resistant Salmonella Kinshasa from dairy calves in Texas.
OBJECTIVE
To determine the prevalence of antimicrobial resistance among Salmonella isolated from a central Texas dairy calf farm that raises animals for dairy-beef production.


RESULTS
Salmonella isolates collected from 50 faecal samples were characterized for susceptibility to 20 antimicrobial agents. Seventy per cent of the faecal samples (35 of 50) tested positive for Salmonella, and high rates of resistance to the following drugs that are commonly used for treatment of bacterial enteritis in livestock were observed: ampicillin (88%), apramycin (83%), neomycin (86%), spectinomycin (91%) and oxytetracycline (90%). No resistance to the fluoroquinolone antibiotics was observed. The most prevalent Salmonella serotype was Kinshasha (22 of 35 samples), followed by Agona (4 of 35), Newport (3 of 35), Infantis (2 of 35), Montevideo (2 of 35), Lille (1 of 35) and Newington (1 of 35). The Kinshasa, Agona, Newport and Infantis serotypes all displayed resistance to ampicillin, chloramphenicol, streptomycin, sulphamethoxazole and tetracycline, and the penta-resistance phenotype was transferable to an Escherichia coli recipient strain.


CONCLUSIONS
Multi-drug resistant Salmonella in dairy calves pose a costly animal health problem and a potential risk to the public health. This study emphasizes the need for alternative, non-antimicrobial intervention strategies for the control of zoonotic pathogens.
Bischoff
K M
KM
US Department of Agriculture, Agricultural Research Service, Southern Plains Agricultural Research Center, TX, USA. bischoff@ffsru.tamu.edu
Edrington
T S
TS
Callaway
T R
TR
Genovese
K J
KJ
Nisbet
D J
DJ
D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle / Q000382:microbiology*; D002701:Chloramphenicol / Q000494:pharmacology; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D005243:Feces / Q000382:microbiology*; D024841:Fluoroquinolones / Q000494:pharmacology; D022761:Gene Transfer, Horizontal; D008826:Microbial Sensitivity Tests; D009328:Nebramycin / Q000031:analogs & derivatives* / Q000494:pharmacology; D009355:Neomycin / Q000494:pharmacology; D010118:Oxytetracycline / Q000494:pharmacology; D011634:Public Health; D012307:Risk Factors; D012475:Salmonella / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D012703:Serotyping; D000198:Spectinomycin / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology; D013420:Sulfamethoxazole / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology; D013781:Texas
D000900:Anti-Bacterial Agents; D024841:Fluoroquinolones; D009328:Nebramycin; C011666:apramycin; D002701:Chloramphenicol; D000667:Ampicillin; D000198:Spectinomycin; D013752:Tetracycline; D009355:Neomycin; D013420:Sulfamethoxazole; D010118:Oxytetracycline; D013307:Streptomycin