Abstract
To compare the efficiency of detecting Haemophilus influenzae type b bacteremia by the BACTEC radiometric system (RS; Johnston Laboratories, Inc., Towson, Md.) and a conventional Trypticase soy broth (BBL Microbiology Systems, Cockeysville, Md.) blood culture system (TSB), we developed an in vivo model of bacteremia in rats. After intravenous injection of 50 to 200 CFU into adult rats, there was a linear logarithmic increase in CFU per milliliter of rat blood during the first 10 h (r = 0.98), allowing accurate prediction of the level of bacteremia with time. Culture bottles were inoculated with 0.5 ml of blood obtained by cardiac puncture and processed as clinical samples in the microbiology laboratory with our RS and conventional protocols. We found the following. (i) The first detection of bacteremia by RS was similar to that by TSB if a Gram stain of the TSB was done on day 1 and was superior if that smear was omitted (P less than 0.01). (ii) The detection times in both systems were comparable at different magnitudes of bacteremia (10(1) to 10(4) CFU/ml). (iii) Supplementation of inoculated bottles with 2 ml of sterile rat blood interfered with Gram stain detection in TSB but resulted in increased 14CO2 production in RS. (iv) No difference in detection time was found between RS and TSB for four different clinical isolates. These studies show that, in a biologically relevant model, the detection of positive blood cultures for H. influenzae type b by RS was comparable to or better than detection by TSB when blood was processed analogously to clinical specimens.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Crist A. E., Jr, Amsterdam D., Neter E. Superiority of hypertonic culture medium for detection of Haemophilus influenzae by the BACTEC procedure. J Clin Microbiol. 1982 Mar;15(3):528–530. doi: 10.1128/jcm.15.3.528-530.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- La Scolea L. J., Jr, Dryja D., Neter E. Comparison of the quantitative direct plating method and the BACTEC procedure for rapid diagnosis of Haemophilus influenzae bacteremia in children. J Clin Microbiol. 1981 Dec;14(6):661–664. doi: 10.1128/jcm.14.6.661-664.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- La Scolea L. J., Jr, Dryja D., Sullivan T. D., Mosovich L., Ellerstein N., Neter E. Diagnosis of bacteremia in children by quantitative direct plating and a radiometric procedure. J Clin Microbiol. 1981 Mar;13(3):478–482. doi: 10.1128/jcm.13.3.478-482.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- La Scolea L. J., Jr, Sullivan T. D., Dryja D., Neter E. Advantages of BACTEC hypertonic culture medium for detection of Haemophilus influenzae bacteremia in children. J Clin Microbiol. 1983 Jun;17(6):1177–1179. doi: 10.1128/jcm.17.6.1177-1179.1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Larson S. M., Charache P., Chen M., Wagner H. N., Jr Automated detection of Haemophilus influenzae. Appl Microbiol. 1973 Jun;25(6):1011–1012. doi: 10.1128/am.25.6.1011-1012.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moxon E. R., Smith A. L., Averill D. R., Smith D. H. Haemophilus influenzae meningitis in infant rats after intranasal inoculation. J Infect Dis. 1974 Feb;129(2):154–162. doi: 10.1093/infdis/129.2.154. [DOI] [PubMed] [Google Scholar]
- Moxon E. R., Vaughn K. A. The type b capsular polysaccharide as a virulence determinant of Haemophilus influenzae: studies using clinical isolates and laboratory transformants. J Infect Dis. 1981 Apr;143(4):517–524. doi: 10.1093/infdis/143.4.517. [DOI] [PubMed] [Google Scholar]
- Santosham M., Moxon E. R. Detection and quantitation of bacteremia in childhood. J Pediatr. 1977 Nov;91(5):719–721. doi: 10.1016/s0022-3476(77)81022-6. [DOI] [PubMed] [Google Scholar]
- Szymczak E. G., Barr J. T., Durbin W. A., Goldmann D. A. Evaluation of blood culture procedures in a pediatric hospital. J Clin Microbiol. 1979 Jan;9(1):88–92. doi: 10.1128/jcm.9.1.88-92.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]