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Multiplexed Lateral Flow Test for Detection and Differentiation of Cronobacter sakazakii Serotypes O1 and O2
Eva J Scharinger1, Richard Dietrich1, Tobias Wittwer2
1Department of Veterinary Science, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität MünchenOberschleißheim, Germany.
Insights
A new rapid test strip can quickly detect and serotype Cronobacter sakazakii O1 and O2 in infant formula. This multiplexed lateral flow assay offers a faster, simpler, and cost-effective alternative to current methods for ensuring infant formula safety.
Area of Science:
- Food safety microbiology
- Pathogen detection
- Immunodiagnostics
Background:
- Cronobacter sakazakii is a dangerous pathogen causing severe illness in infants, often linked to contaminated powdered infant formula (PIF).
- Existing methods for Cronobacter detection are slow, labor-intensive, and costly, hindering rapid response.
- Accurate and swift identification of specific C. sakazakii serotypes is crucial for public health interventions.
Purpose of the Study:
- To develop a rapid, multiplexed lateral flow assay (LFA) for simultaneous detection and serotyping of C. sakazakii serotypes O1 and O2.
- To provide a cost-effective and user-friendly diagnostic tool for C. sakazakii in PIF.
- To overcome the limitations of conventional microbiological methods.
Main Methods:
- Development of a multiplexed lateral flow test strip utilizing two monoclonal antibodies (MAbs).
- Assay targets specific lipopolysaccharides (LPS) of C. sakazakii serotypes O1 and O2.
- Testing with pure cultures and PIF samples after enrichment.
Main Results:
- The LFA detected C. sakazakii in pure culture within 15 minutes at 10^7 CFU/ml.
- Sensitivity reached as low as one Cronobacter cell per gram of PIF after an 18-hour enrichment.
- The assay demonstrated high specificity, with no cross-reactivity against other C. sakazakii serotypes, Cronobacter species, or Enterobacteriaceae.
Conclusions:
- The developed multiplexed LFA provides rapid, specific, and sensitive detection and serotyping of C. sakazakii O1 and O2.
- Its speed, simplicity, low cost, and minimal equipment requirements make it suitable for routine food safety testing.
- This assay represents a significant advancement over traditional methods for ensuring the safety of infant formula.
Abstract:
The ubiquitous and opportunistic pathogen Cronobacter sakazakii is responsible for severe meningitis, sepsis, and necrotizing enterocolitis in neonates and infants associated with ingestion of contaminated powdered infant formula (PIF). The current ISO method for isolation and detection of Cronobacter spp. is laborious, time-consuming and expensive. In this study, a multiplexed lateral flow test strip was developed to rapidly detect and simultaneously serotype O1 and O2 C. sakazakii serotypes. The assay is based on two monoclonal antibodies (MAb) that specifically bind to the lipopolysaccharides (LPS) of these pathogens. The test strip provides results very quickly; C. sakazakii could be detected in pure culture within 15 min with a sensitivity of 107 CFU/ml. After non-selective enrichment for 18 h as low as one Cronobacter cell per g PIF could be detected. Moreover, the established lateral flow assay (LFA) offers excellent specificity showing no cross-reactivity with other C. sakazakii serotypes, Cronobacter species or Enterobacteriaceae tested. These characteristics, together with several advantages such as speed, simplicity in performance, low analysis cost, and no requirement of specialized skills or sophisticated equipment make the developed multiplexed LFA suitable for reliable detection and serotyping of C. sakazakii serotypes O1 and O2.
