Comparison of media and culture techniques for detection of Streptococcus pneumoniae in respiratory secretions.

Journal of Clinical Microbiology (Impact Factor: 4.07). 01/1981; 12(6):772-5.
Source: PubMed

ABSTRACT We compared the relative efficacy of three methods for the isolation of Streptococcus pneumoniae in lower respiratory secretions. Based on results from 294 clinical specimens, we found that S. pneumoniae was isolated at a frequency of 65% with 5% sheep blood agar or 5% sheep blood agar containing 5 micrograms of gentamicin per ml, both incubated in 5% CO2. Anaerobic incubation of 5% sheep blood agar enhanced the recovery rate of S. pneumoniae to 93%. The improved efficacy with anaerobic incubation is due to the greater ease of recognition of the larger and more mucoid colonies of S. pneumoniae, and to the suppression of the growth of other oral bacteria present in the respiratory sections.

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    ABSTRACT: Streptococcus pneumoniae is the most common cause of community-acquired pneumonia. However, it can also asymptomatically colonize the upper respiratory tract. Because of the need to distinguish between S. pneumoniae that is simply colonizing the upper respiratory tract and S. pneumoniae that is causing pneumonia, accurate diagnosis of pneumococcal pneumonia is a challenging issue that still needs to be solved. Sputum Gram stains and culture are the first diagnostic step for identifying pneumococcal pneumonia and provide information on antibiotic susceptibility. However, these conventional methods are relatively slow and insensitive and show limited specificity. In the past decade, new diagnostic tools have been developed, particularly antigen (teichoic acid and capsular polysaccharides) and nucleic acid (ply, lytA, and Spn9802) detection assays. Use of the pneumococcal antigen detection methods along with biomarkers (C-reactive protein and procalcitonin) may enhance the specificity of diagnosis for pneumococcal pneumonia. This article provides an overview of current methods of diagnosing pneumococcal pneumonia and discusses new and future test methods that may provide the way forward for improving its diagnosis.
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    ABSTRACT: The use of anaerobic incubation for the culture of Streptococcus pneumoniae from sputum was compared with incubation in carbon dioxide in air. A coagglutination test for pneumococcal antigen was used as an index of the number of specimens containing pneumococci. A total of 334 specimens were examined. There was evidence of pneumococcal colonisation by culture or coagglutination, or both, in 48 (14.37%), of which 41 (12.27%) yielded S pneumoniae on culture. Anaerobic incubation was better than incubation in carbon dioxide in air for the primary culture of S pneumoniae from sputum. Primary isolation of S pneumoniae was achieved in 11 of the 41 strains (26.82%) by anaerobic incubation alone, by incubation only in carbon dioxide in air in one strain (2.43%), and by both anaerobic incubation and incubation in carbon dioxide in air in 29 strains (70.73%). Anaerobic incubation gave large moist or mucoid colonies that were easy to recognise, but it suppressed the typical draughtsman colony of S pneumoniae. The factor V supplement routinely used in our medium also inhibited the formation of draughtsman colonies. It is suggested that draughtsman colonies occur because of a relative lack of the coenzyme nicotinamide adenine dinucleotide (factor V), which is required as a reducing agent in aspartate and glutamate metabolism. This nutritional deficiency may lead to bacterial cell wall defect and hence to the autolysis which gives the typical draughtsman colony.
    Journal of Clinical Pathology 05/1987; 40(4):368-71. · 2.44 Impact Factor
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    ABSTRACT: Six anaerobic oral spirochetes designated strains a, b, c, d, e, and e’ were isolated randomly from periodontal pockets and were maintained in pure culture. The strains were found to belong to the genus Treponema. All strains were similar in cultural, morphological, biochemical, and physiological properties with the exception of the following features: strains c and d were more fastidious nutritionally for sodium bicarbonate as a medium supplement than the other strains; they differed in the number of axial fibrils; and they were also serologically distinct from strains a, b, e, and e’ by agglutination tests and fluorescent immunoassays. However, DNA homology studies indicated that all the isolates were strains of Treponema denticola with divergent phenotypic and serological properties. Serovar a and serovar c, representing two different serogroups, have been deposited in the American Type Culture Collection with the accession numbers ATCC 35405 and ATCC 35404, respectively.
    Journal of Periodontal Research 12/1985; 20(6):602-12. · 1.99 Impact Factor


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