Surveillance and molecular typing of Cronobacter spp. in commercial powdered infant formula and follow-up formula from 2011 to 2013 in Shandong Province, China.
BACKGROUND
Infection with Cronobacter spp. leads to neonatal meningitis, necrotizing enterocolitis and bacteremia. Cronobacter spp. are reported to comprise an important pathogen contaminating powdered infant formula (PIF) and follow-up formula (FUF), although little is known about the contamination level of Cronobacter spp. in PIFs and FUFs in China.


RESULTS
In total, 1032 samples were collected between 2011 and 2013. Forty-two samples were positive, including 1.6% in PIFs and 6.5% in FUFs. The strains were susceptible to most antibiotics except for cefoxitin. Pulsed-field gel electrophoresis after XbaI digestion produced a total of 36 banding patterns. The 38 strains were found in 27 sequence types (STs), of which nine types (ST454 to ST462) had not been reported in other countries. The clinically relevant strains obtained from the 38 isolates in the present study comprised three ST3, two ST4, two ST8 and one ST1.


CONCLUSIONS
The contamination rate in the PIF and FUF has stayed at a relatively high level. The contamination rate of PIF was significantly lower than FUF. The isolates had high susceptibility to the antibiotics tested, except cefoxitin. There were polymorphisms between the Cronobacter spp. as indicated by pulsed-field gel electrophoresis and multilocus sequence typing. Therefore, contamination with Cronobacter spp. remains a current issue for commercial infant formulas in China. © 2016 Society of Chemical Industry.
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Huaning
H
Zhang
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Peibin
P
Hou
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Hui
H
Lv
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Yuzhen
Y
Chen
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Xinpeng
X
Li
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Yanyan
Y
Ren
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Mei
M
Wang
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Hailian
H
Tan
Shandong Center for Disease Control and Prevention, Jinan, China.|Academy of Preventive Medicine, Shandong University, Jinan, China.|Shandong Provincial Key Laboratory of Infectious Disease Control and Prevention, Jinan, China.
Zhenwang
Z
Bi
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002681:China; D059126:Cronobacter / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination / Q000032:analysis* / Q000191:economics / Q000706:statistics & numerical data; D059022:Food Safety; D041943:Infant Formula / Q000191:economics / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing
D000900:Anti-Bacterial Agents
Cronobacter spp; PFGE and MLST; PIF and FUF; antibiotic susceptibility