Highly Drug-Resistant Salmonella enterica Serovar Indiana Clinical Isolates Recovered from Broilers and Poultry Workers with Diarrhea in China

Abstract

Highly drug-resistant Salmonella enterica serovar Indiana became the most common serovar in broilers with diarrhea in China over the course of this study (15% in 2010 to 70% in 2014). While most S. Indiana isolates (87%, 384/440) were resistant to 13 to 16 of the 16 antibiotics tested, 89% of non-S. Indiana isolates (528/595) were resistant to 0 to 6 antibiotics. Class 1 integrons and IncHI2-type plasmids were detected in all S. Indiana isolates, but only in 39% and 1% of non-S. Indiana isolates.

FIG 1

The five most prevalent Salmonella serovars from broilers with diarrhea, 2010-2014. The percentage of S. Indiana among Salmonella serovars rose from 15% in 2010 to 70% in 2014.

FIG 2

Antimicrobial resistance to 16 antibiotics of Salmonella isolates from broilers and poultry workers with diarrhea. The columns denote the percentages of 595 non-S. Indiana isolates (top) from broilers, 428 S. Indiana isolates (middle) from broilers, and 12 S. Indiana isolates (bottom) from poultry workers that were resistant, intermediate, or susceptible to 16 common antibiotics. AMP, ampicillin; CTX, cefotaxime; CRO, ceftriaxone; CAZ, ceftazidime; ATM, aztreonam; GEN, gentamicin; AMK, amikacin; STR, streptomycin; TET, tetracycline; CIP, ciprofloxacin; NAL, nalidixic acid; SXT, trimethoprim-sulfamethoxazole; SUL, sulfafurazole; TMP, trimethoprim; CHL, chloramphenicol; NIT, nitrofurantoin.

FIG 3

Changes in multidrug resistance patterns among S. Indiana isolates from poultry (2010-2014). The columns denote the percentages of 428 avian S. Indiana isolates that were resistant to 9 or 10 antibiotics, 11 or 12 antibiotics, 13 or 14 antibiotics, and 15 or 16 antibiotics.