Comparative Genotypic and Phenotypic Analysis of Cronobacter Species Cultured from Four Powdered Infant Formula Production Facilities: Indication of Pathoadaptation along the Food Chain |
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| Authors: | Qiongqiong Yan Juan Wang Jayanthi Gangiredla Yu Cao Marta Martins Gopal R Gopinath Roger Stephan Keith Lampel Ben D Tall Séamus Fanning |
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| Institution: | aUCD Centre for Food Safety, WHO Collaborating Centre for Research, Reference & Training on Cronobacter, School of Public Health, Physiotherapy & Population Science, University College Dublin, Belfield, Dublin, Ireland;bU.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, OARSA, Silver Spring, Maryland, USA;cInstitute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland |
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| Abstract: | Cronobacter species are opportunistic pathogens commonly found in the environment. Among the seven Cronobacter species, Cronobacter sakazakii sequence type 4 (ST-4) is predominantly associated with recorded cases of infantile meningitis. This study reports on a 26-month powdered infant formula (PIF) surveillance program in four production facilities located in distinct geographic regions. The objective was to identify the ST(s) in PIF production environments and to investigate the phenotypic features that support their survival. Of all 168 Cronobacter isolates, 133 were recovered from a PIF production environment, 31 were of clinical origin, and 4 were laboratory type strains. Sequence type 1 (n = 84 isolates; 63.9%) was the dominant type in PIF production environments. The majority of these isolates clustered with an indistinguishable pulsotype and persisted for at least an 18-month period. Moreover, DNA microarray results identified two phylogenetic lineages among ST-4 strains tested. Thereafter, the ST-1 and -4 isolates were phenotypically compared. Differences were noted based on the phenotypes expressed by these isolates. The ST-1 PIF isolates produced stronger biofilms at both 28°C and 37°C, while the ST-4 clinical isolates exhibited greater swimming activity and increased binding to Congo red dye. Given the fact that PIF is a low-moisture environment and that the clinical environment provides for an interaction between the pathogen and its host, these differences may be consistent with a form of pathoadaptation. These findings help to extend our current understanding of the epidemiology and ecology of Cronobacter species in PIF production environments. |
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