A new cost-effective, selective and differential medium for the isolation of Cronobacter spp.

S. A. Kim, Min-Suk Rhee

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The objective of the present study was to develop a new selective, differential and cost-effective medium (Kim and Rhee - KR-medium) for the isolation of Cronobacter spp. In this new medium, which contained salicin as a differential agent, Cronobacter spp. generated typical colonies with characteristic violet-colored centers surrounded by a transparent to opalescent border, and the growth of other microorganisms (40 strains) was inhibited or produced visually distinguishable colonies. Using healthy and heat- and desiccation-injured cells, the quantity of nutrients was adjusted to determine the optimal recovery rate, selectivity, differentiation and cost-effectiveness. Peptone and salicin concentrations were established as 10 and 8. g/L, respectively. The KR medium was then validated using salicin fermenting organisms, including Cronobacter spp. (52 strains), Enterobacter cloacae (50 strains) and Klebsiella pneumonia (10 strains) isolated from clinical and food specimens. All strains of Cronobacter spp. produced typical colonies and other salicin fermenting organisms were easily distinguishable from Cronobacter spp. with the exception of 2 E. cloacae strains. The verification of KR medium was carried out in powdered infant formula artificially inoculated with healthy, heat-injured, and desiccation-injured Cronobacter spp. and the expected typical colonies were appeared. The KR medium had a high specificity (98%) and sensitivity (100%), with no false-negative results. Moreover, we show that the cost of the KR medium is much lower than that of other selective and differential media. The use of the KR medium for the selective isolation of Cronobacter spp. in laboratories and food industry settings may therefore lessen the financial burden of Cronobacter spp. detection.

Original languageEnglish
Pages (from-to)149-154
Number of pages6
JournalJournal of Microbiological Methods
Volume85
Issue number2
DOIs
Publication statusPublished - 2011 May 1

Fingerprint

Cronobacter
Costs and Cost Analysis
Enterobacter cloacae
Desiccation
Hot Temperature
Viola
Food
Peptones
Infant Formula
Food Industry
Klebsiella pneumoniae
Cost-Benefit Analysis

Keywords

  • Cronobacter spp.
  • Isolation
  • Salicin
  • Selective and differential medium

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Microbiology (medical)

Cite this

A new cost-effective, selective and differential medium for the isolation of Cronobacter spp. / Kim, S. A.; Rhee, Min-Suk.

In: Journal of Microbiological Methods, Vol. 85, No. 2, 01.05.2011, p. 149-154.

Research output: Contribution to journalArticle

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