Related Experiment Video
Updated: Jul 4, 2026
Foodborne Pathogen Screening Using Magneto-fluorescent Nanosensor: Rapid Detection of E. Coli O157:H7
Published on: September 17, 2017
Development of an immobilization and detection method of Enterobacter sakazakii from powdered infant formula
Yanhong Zhou1, Qingping Wu, Xiaoke Xu
1Wuhan Institute of Virology, Chinese Academy of Science, Wuhan 430071, China. mylovelyswallow@yeah.net
Insights
A new method immobilizes Enterobacter sakazakii for detection using duplex PCR. This rapid technique accurately identifies the pathogen in infant formula, improving food safety for infants.
Area of Science:
- Microbiology
- Food Safety
- Molecular Diagnostics
Background:
- Enterobacter sakazakii is an opportunistic pathogen causing severe infant infections.
- Current detection methods for E. sakazakii in infant formula can be slow and less sensitive.
Purpose of the Study:
- To develop a rapid and efficient method for detecting Enterobacter sakazakii in powdered infant formula (PIF).
- To improve the sensitivity and accuracy of E. sakazakii detection in PIF samples.
Main Methods:
- Developed a procedure for immobilizing E. sakazakii using zirconium hydroxide.
- Utilized a species-specific duplex PCR targeting 16s-23s rDNA ITS and ompA gene for detection.
- Tested the method's efficacy on pure cultures, inoculated PIF, and commercial PIF samples.
Main Results:
- The immobilization and duplex PCR method achieved high recovery rates (79.4%-99.6%) for pure E. sakazakii cultures.
- Detection limit in PIF was as low as 3x10(0) CFU/ml after enrichment.
- The method detected E. sakazakii in 7 out of 13 commercial PIF samples, compared to 3 by biological methods.
Conclusions:
- The combination of zirconium hydroxide immobilization and duplex PCR is a sensitive, rapid, and efficient method for E. sakazakii detection.
- This approach offers significant advantages over traditional biological methods for PIF analysis.
- The developed method has potential for widespread application in ensuring infant formula safety.
Abstract:
Enterobacter sakazakii is an emerging opportunistic pathogen that is associated with rare but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in premature and full-term infants. In the present study, a procedure was developed for immobilization of E. sakazakii with zirconium hydroxide coupled with detection by a species-specific duplex PCR, based on 16s-23s rDNA internal transcribed spacer (ITS) and ompA gene. Specificity of duplex PCR was tested against two-type strains, six isolates of E. sakazakii and other eight non-E. sakazakii species. When pure culture of E. sakazakii was used for immobilization, total recovery rate ranged from 79.4% to 99.6% of input bacteria, and the detection limit of duplex PCR was 3x10(5)CFU/ml. Different levels of E. sakazakii were inoculated into 90ml reconstituted powdered infant formula (PIF), and detection limit of duplex PCR was 3x10(0)CFU/ml with 24-30h enrichment after immobilization. When the experiment was performed in the presence of 10(2)CFU/ml Salmonella typhimurium, the detection limit of duplex PCR was not affected after enrichment. Seven out of 13 commercial PIF were detected positive by duplex PCR after immobilization, while only three were positive by biological methods. This study demonstrates that the combination of immobilization method with duplex PCR is easy, rapid, and efficient, and may have applications for the detection of E. sakazakii in more PIF samples.
