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. 2009 Apr 7;10(4):1538-1551.
doi: 10.3390/ijms10041538.

Resistance to β-lactams in bacteria isolated from different types of Portuguese cheese

Paula Amador  1   2   3 , Ruben Fernandes  2 , Cristina Prudêncio  2 , Luísa Brito  1
Affiliations

Resistance to β-lactams in bacteria isolated from different types of Portuguese cheese

Paula Amador et al. Int J Mol Sci. .

Abstract

The purpose of this study was to investigate the presence of beta-lactam-resistant bacteria in six different types of Portuguese cheese. The numbers of ampicillin resistant (AMP(r)) bacteria varied from 4.7 x 10(2) to 1.5 x 10(7) CFU/g. Within 172 randomly selected beta-lactam-resistant bacteria, 44 resistant phenotypes were found and 31.4% were multidrug resistant. The majority (85%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the bla(TEM) gene was detected in 80.9% of the tested isolates. The results suggest that without thermal processing of the milk and good hygienic practices, cheese may act as a vehicle of transfer of beta-lactam-resistant bacteria to the gastrointestinal tract of consumers.

Keywords: Ready-to-eat (RTE) food; blaTEM gene; cheese, minimal inhibitory concentration (MIC); multiplex-PCR; β-lactam-resistant Enterobacteriaceae.

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Figures

Figure 1.
Figure 1.
Mean values of ampicillin resistant (AMPr) bacteria (CFU/g of cheese) ± the standard deviation (error bars), on VRBG agar medium, after 38 hours at 37 ºC.
See this image and copyright information in PMC

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