title: Prevalence and characterization of Salmonella enterica in dried milk-related infant foods in Shaanxi, China.
abstract: The aim of this study was to investigate the existence and characteristics of Salmonella enterica in dried milk-related infant foods. Twenty-four (3.4%) of 705 samples, including 5 (2.0%) of 246 powdered infant formula, 18 (4.0%) of 445 infant rice cereal, and 1 (7.1%) of 14 other infant foods, were positive for Salmonella. Fifteen serotypes were identified in 40 Salmonella isolates; Salmonella Duesseldorf (15.0%) and Salmonella Indiana (15.0%) were more frequently detected than other serotypes. Resistance to chloramphenicol (82.5%) was most common, followed by tetracycline (57.5%), ceftiofur (52.5%), kanamycin (52.5%), streptomycin (50.0%), gentamycin (45.0%), nalidixic acid (35.0%), ceftriaxone (32.5%), ciprofloxacin (25.0%), amikacin (20.0%), and cefoxitin (15.0%). Twenty-eight (70.0%) isolates were resistant to ≥ 8 antimicrobials, with 5 (12.5%) being resistant to 14 antimicrobials. Amino acid substitutions in gyrase A (GyrA) were most frequently detected as Ser83Arg/Asp87Glu and in p53-associated Parkin-like cytoplasmic protein (ParC), they were all Ser80Arg; the quinolone resistance gene qnrS (47.5%) was commonly detected as well as aminoglycoside acetyltransferase [aac(6')-Ib; 25.0%], qnrA (17.5%), and qnrB (15.0%) genes. Thirty distinct pulsed-field gel electrophoresis patterns were identified among 40 isolates; no identical pulsed-field gel electrophoresis pattern was detected among Salmonella isolates with the same serovar that was recovered in 2010 and 2012. Our results suggest that dried milk-related infant foods could be contaminated with Salmonella and highlight that the dangers to infant health should not be neglected.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: B
authors.initials: B
authors.lastname: Yang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: H
authors.initials: H
authors.lastname: Zhao
authors.affiliation: National Institutes for Food and Drug Control, Beijing 100050, China.
authors.forename: S
authors.initials: S
authors.lastname: Cui
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: X
authors.initials: X
authors.lastname: Xia
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: M
authors.initials: M
authors.lastname: Xi
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; Joint Institute for Food Safety and Applied Nutrition, and Department of Nutrition and Food Science, University of Maryland, College Park 20742.
authors.forename: J
authors.initials: J
authors.lastname: Meng
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China. Electronic address: josephge@nwsuaf.edu.cn.
authors.forename: W
authors.initials: W
authors.lastname: Ge
mesh_terms: D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D005798:Genes, Bacterial; D041943:Infant Formula / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology*; D012475:Salmonella / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*; D017422:Sequence Analysis, DNA
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D000123:Acetyltransferases; C019681:aminoglycoside acetyltransferase
keywords: Salmonella; antimicrobial resistance; infant food; pulsed-field gel electrophoresis