Fastidious organisms

Approximately 90% of the first two cultures will yield a positive result. If a positive blood culture is not obtained from a patient with suspected IE, the microbiology laboratory should be notified and cultures requested to be monitored for growth of fastidious organisms for up to 1 month. 

Additionally the slow growth rate of the methane formers which has always caused some problems with wash-out or overgrowth would be entirely eliminated without filtering, centrifuging, or in any way handling these fastidious organisms. 

Jorgensen JH, Ferraro MJ. Antimicrobial susceptibility testing Special needs for fastidious organisms and difficult-to-detect resistance mechanisms. Clin Infect Dis 2000 30 799-808. 

Brucella are very fastidious organisms requiring a rich growth medium. They are also slow growing, and media are therefore supplemented by a cocktail of... 

E-tests can be used to determine MIC for fastidious organisms such as Streptococcus pneumoniae, P-haemolytic streptococci, Neisseria gonorrhoeae, Haemophilus sp. and anaerobes. It can also be used for non-fermenting Gram-negative bacilli, e.g.. Pseudomonas sp. and Burkholderia pseudomallei. 

Myxobacteria have a reputation of being particularly fastidious organisms, but in fact many species can be grown in pure culture. As with all other microorganisms, myxobacteria exhibit peculiarities, of course, but they do not have unusual or particularly complex nutrient and growth requirements. In general, there are two nutritional types among the myxobacteria Most species are characterized... 

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