AUTHOR=Fei Peng , Jiang Yujun , Feng Jing , Forsythe Stephen J. , Li Ran , Zhou Yanhong , Man Chaoxin 

TITLE=Antibiotic and Desiccation Resistance of Cronobacter sakazakii and C. malonaticus Isolates from Powdered Infant Formula and Processing Environments

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00316

DOI=10.3389/fmicb.2017.00316

ISSN=1664-302X

ABSTRACT=<p>This study evaluated the antimicrobial and desiccation resistance of <italic>Cronobacter sakazakii</italic> and <italic>Cronobacter malonaticus</italic> isolates from powdered infant formula and processing environments. The antimicrobial susceptibility tests showed that the 70 <italic>Cronobacter</italic> strains, representing 19 sequence types, were susceptible to the most of the antibiotics except for amoxicillin-clavulanate, ampicillin, and cefazolin. Furthermore, the growth of six <italic>C. sakazakii</italic> and two <italic>C. malonaticus</italic> strains from different sequence types (STs) in hyperosmotic media was measured. The growth of the two <italic>C. sakazakii</italic> strains (CE1 and CE13) from the neonatal pathovars ST4 and ST8, were significantly higher (<italic>p</italic> &lt; 0.05) than that of other strains. <italic>C. malonaticus</italic> strain CM35 (ST201) was the slowest grower in all strains, and most could not grow in more than 8% NaCl solution. Also the survival of these strains under desiccation conditions was followed for 1 year. The viable count of <italic>Cronobacter</italic> spp. under desiccation conditions was reduced on average by 3.02 log cycles during 1 year, with CE13 (ST8) being the most desiccation resistant strain. These results will improve our understanding of the persistence of the two closely related species <italic>C. sakazakii</italic> and <italic>C. malonaticus</italic> which are of concern for neonatal and adult health.</p>