NAS agar is more suitable than McKay agar for primary culture of Streptococcus milleri group (SMG) fastidious bacteria, S. intermedius in particular
Language English Country United States Media print-electronic
Document type Comparative Study, Evaluation Study, Journal Article
PubMed
27638003
DOI
10.1007/s12223-016-0470-y
PII: 10.1007/s12223-016-0470-y
Knihovny.cz E-resources
- MeSH
- Agar MeSH
- Bacteriological Techniques methods MeSH
- Culture Media chemistry MeSH
- Humans MeSH
- Streptococcus milleri Group isolation & purification MeSH
- Streptococcal Infections diagnosis MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Evaluation Study MeSH
- Comparative Study MeSH
- Names of Substances
- Agar MeSH
- Culture Media MeSH
Streptococcus milleri group (SMG) is a group of three streptococcal species (S. anginosus, intermedius and constellatus) that act as opportunist pathogens, among others in cystic fibrosis. Due to their fastidious character, they are both difficult to cultivate and to differentiate from less pathogenic streptococcal species, therefore being most probably underdiagnosed. Semi-selective McKay agar and NAS agar were developed to facilitate SMG recovery from clinical samples; however, direct comparison of recovery rates has not been published yet. We tested the performance of both media on 123 patient samples and demonstrated general superiority of NAS agar for SMG recovery during primary cultivation convincingly. This observation was also confirmed by quantitative drop tests during subculture. Despite the undisputed overall superiority of NAS agar over McKay agar, a smaller fraction of strains grew better on McKay agar. Inter-strain differences were the most probable explanation. Therefore, when economic conditions are not limiting and maximum recovery rate is desirable, both plates are advised to be used in parallel for primary cultivation of clinical samples.
Department of Pediatrics University Hospital Olomouc 1 P Pavlova 6 Olomouc Czech Republic
Department of Respiratory Medicine University Hospital Olomouc 1 P Pavlova 6 Olomouc Czech Republic
Department of Surgery 1 University Hospital Olomouc 1 P Pavlova 6 Olomouc Czech Republic
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