Comparison of two sampling methods for the detection of Gram-positive and Gram-negative bacteria in the environment: moistened swabs versus Rodac plates
Sw. Lemmen et al., Comparison of two sampling methods for the detection of Gram-positive and Gram-negative bacteria in the environment: moistened swabs versus Rodac plates, INT J HYG E, 203(3), 2001, pp. 245-248
Citations number
15
Categorie Soggetti
Medical Research General Topics
Journal title
INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH
The objective of this study was to evaluate the moistened swab technique vs
. Rodac plates for detecting Gram-positive and Gram-negative bacteria in th
e inanimate environment.
Over a period of 22 months, the environment of 190 patients infected or col
onized with MRSA, VRE or multiresistant Gram-negative bacteria was sampled
in turn. MRSA and VRE could be detected with either method in 33 out of 54
(61.1 %) patient rooms in 174 out of 706 (24.6 %) environmental samples. Ho
wever, multiresistant Gram-negative bacteria were found in 42 out of 136 (3
0.9 %) rooms with a very low frequency of 89 out of 1827 (4.9 %) environmen
tal samples (p < 0.0001). The sensitivity of the swab technique for Gram-po
sitive cocci was 54 % (94/174) vs. 69.5 % (121/174) for the Rodac plates, (
[CI95 %], 47-61 % vs. 62-76 %, P < 0.05). In contrast, the sensitivity of t
he swab technique for Gram-negative bacteria was 74.2 % (66/89) vs. 42.7 %
(38/89) for the Rodac plates, ([CI95 %], 64-83 % vs. 32-54 %, p < 0.05).
In conclusion, environmental contamination with Gram positive cocci is dete
cted more often than with Gram-negative bacteria. For the detection of Gram
-positive cocci, Rodac plates are superior to the swab technique; whereas G
ram-negative rods can be detected more often by the swab technique. hll the
se results proved to be statistically significant.