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. 2019 Jun 17;85(13):e00037-19. doi: 10.1128/AEM.00037-19

TABLE 3.

Effect of cessation of in ovo administration of ceftiofur and replacement with lincomycin-spectinomycin on the proportions of ceftriaxone-enriched samples from newly hatched, broiler, and breeder birds harboring isolates nonsusceptible to antimicrobials of different classes in the collection of ESBL/AmpC resistance gene-positive E. colia

Sample origin Before or after
ceftiofur cessation
in broiler		 Antimicrobial(s)
administered in ovo 		No. of
samples
(isolates)		 Proportion (%) of nonsusceptible samples by category,b by classc of antimicrobial, and by antimicrobiald
Critically important
 Highly important
Highest priority
 High priority
FLQ
 CPS
 MAC
 PEN
 PEN/I
 AMG
 CPM
 FOL
 PHE
 TET
NA CIP TIO CRO AZM AMP AMC GEN SPT STR FOX SXT SSS CHL
Meconium Before (2014) Ceftiofur 19 (38) 5 0 100 100 5 100 100 47A 37A 63A 100 5A 68A 16 68
After (2015) None 14 (28) 0 0 100 100 0 100 93 64 36A 79 93 29 86 29 79
After (2015) Lincomycin-spectinomycin 16 (32) 6 0 100 100 0 100 100 88B 81B 100B 100 38B 100B 38 88
Pooled feces
of broilers		 Before (2014) Ceftiofur 20 (40) 15 0 100 100 10 100 100 45 25A 85 100 65A 85 25 85
After (2015) None 14 (28) 7 0 100 100 0 100 100 71 50 71A 100 7B 86 7A 50A
After (2015) Lincomycin-spectinomycin 16 (32) 13 0 100 100 0 100 100 69 69B 100B 94 75A 100 44B 94B
Pooled feces
of breeders		 Before (2014) Ceftiofur in 2014 22 (44) 0 0 95 100 9 100 95 41 36 82 95 14 50 32 82
Before (2015) Ceftiofur in 2015 24 (48) 4 4 100 100 4 100 96 50 38 75 96 17 58 25 71
a

Tested by the Kirby-Bauer method. Different letters in the same column of results for antimicrobial and same sample origin indicate significantly different results.

b

Category of human antimicrobial importance according to the World Health Organization (WHO) (7).

c

Abbreviations for antimicrobial classes: FLQ, fluoroquinolones; CPS, cephalosporins; MAC, macrolides; PEN, penicillins; PEN/I, penicillins plus β-lactamase inhibitors; AMG, aminoglycosides; CPM, cephamycins; FOL, folate inhibitors; PHE, phenicols; TET, tetracyclines.

d

Abbreviations for antimicrobials: NA, nalidixic acid; CIP, ciprofloxacin; TIO, ceftiofur; CRO, ceftriaxone; AZM, azithromycin; AMP, ampicillin; AMC, amoxicillin-clavulanic acid; GEN, gentamicin; SPT, spectinomycin; STR, streptomycin; FOX, cefoxitin; SXT, trimethoprim-sulfamethoxazole; SSS, sulfisoxazole; CHL, chloramphenicol; TET, tetracycline.