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Vancomycin-resistant gram-positive bacteria isolated from human sources
K L Ruoff1, D R Kuritzkes, J S Wolfson
1Francis Blake Bacteriology Laboratories, Massachusetts General Hospital, Boston 02114.
Abstract:
Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.
Insights
Vancomycin-resistant gram-positive bacteria, primarily Lactobacillus, Leuconostoc, and Pediococcus species, were identified in human samples. Some vancomycin-resistant lactobacilli from sterile sites were clinically significant, suggesting an emerging threat.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Diagnostics
Background:
- Reports of vancomycin-resistant gram-positive bacteria infections are increasing.
- Understanding the diversity of these resistant bacteria is crucial for public health.
- Identification of novel resistant strains necessitates further investigation.
Purpose of the Study:
- To characterize vancomycin-resistant gram-positive bacterial isolates from human sources.
- To identify the specific bacterial genera exhibiting vancomycin resistance.
- To assess the clinical significance of these resistant isolates.
Main Methods:
- Analysis of 36 vancomycin-resistant gram-positive isolates from clinical and stool samples.
- Morphological and physiological testing for bacterial identification.
- Genus-level identification using standard microbiological techniques.
Main Results:
- Twenty-five Lactobacillus, 6 Leuconostoc, and 3 Pediococcus species were identified.
- Two isolates could not be assigned to a genus due to indeterminate morphology.
- Four vancomycin-resistant Lactobacillus isolates from sterile sites were clinically significant.
Conclusions:
- Vancomycin-resistant gram-positive bacteria, including Lactobacillus, Leuconostoc, and Pediococcus, are present in human samples.
- These resistant organisms may represent an emerging class of nosocomial pathogens.
- Improved laboratory methods are needed for accurate identification of these genera.