Abstract
A simple procedure is presented whereby an antibiotic solution can be added to prepared agar media for conversion to a selective medium to isolate fungi. Gentamicin solution was deposited onto slants of a variety of previously prepared agar media, allowed to diffuse overnight, and then the slants were inoculated with clinical specimens. Control media without gentamicin included a cycloheximide-chloramphenicol medium (CC), Sabouraud dextrose agar (SDA), and brain heart infusion agar (BHI). Of 75 specimens originating from the respiratory tract, the fungi isolated were predominantly yeast; 35, 39, and 43 were positive on CC, SDA, and SDA with gentamicin, respectively, incubated at 25 C. At 37 C, 32, 34, and 41 positive cultures were obtained with the same media, respectively. The same specimens, inoculated onto BHI with and without gentamicin, yielded 23 and 39 positive cultures, respectively. Of 90 specimens that were either urine, cutaneous, or mucocutaneous, the predominant flora again were yeasts, although on nine occasions dermatophytes were isolated. Positive cultures, 32, 34, and 41, were obtained with CC, SDA, and SDA containing gentamicin, respectively. Bacterial contamination was significantly reduced by the gentamicin, especially on BHI incubated at 37 C. None of the specimens was positive for systemically pathogenic fungi, other than species of Candida, Torulopsis, and Aspergillus. The effectiveness of varying concentrations of gentamicin was investigated by comparing growth of recently isolated bacteria. Of the bacterial isolates, 33% grew on CC, 16% grew on SDA containing gentamicin, 50 mug/ml, and 3% grew on SDA with a gentamicin concentration at 100 mug/ml. With BHI, 3% grew in the presence of 50 mug of gentamicin/ml and less than 1% grew at 100 mug of gentamicin/ml.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Casemore D. P. Gentamicin as a bactericidal agent in virological tissue cultures. J Clin Pathol. 1967 May;20(3):298–299. doi: 10.1136/jcp.20.3.298. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cohen S. N. Modified Sabouraud medium containing neomycin and polymyxin. Appl Microbiol. 1969 Mar;17(3):486–487. doi: 10.1128/am.17.3.486-487.1969. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Collins M. S. Inhibition of growth of Coccidioides immitis on Sabouraud medium containing polymyxin B. J Clin Microbiol. 1975 Mar;1(3):335–336. doi: 10.1128/jcm.1.3.335-336.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dolan C. T. Effect of gentamicin on growth of yeasts, yeast-like organisms, and Aspergillus fumigatus. Am J Clin Pathol. 1972 Jan;57(1):30–32. doi: 10.1093/ajcp/57.1.30. [DOI] [PubMed] [Google Scholar]
- Dolan C. T. Optimal combination and concentration of antibiotics in media for isolation of pathogenic fungi and Nocardia asteroides. Appl Microbiol. 1971 Feb;21(2):195–197. doi: 10.1128/am.21.2.195-197.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lerner P. I., Baum G. L. Antimicrobial susceptibility of Nocardia species. Antimicrob Agents Chemother. 1973 Aug;4(2):85–93. doi: 10.1128/aac.4.2.85. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Litwin J. The effect of commercial and pure gentamicin on the growth of human diploid lung fibroblasts. Acta Pathol Microbiol Scand B Microbiol Immunol. 1970;78(3):273–276. doi: 10.1111/j.1699-0463.1970.tb04302.x. [DOI] [PubMed] [Google Scholar]
- Rudin A., Healey A., Phillips C. A., Gump D. W., Forsyth B. R. Antibacterial activity of gentamicin sulfate in tissue culture. Appl Microbiol. 1970 Dec;20(6):989–990. doi: 10.1128/am.20.6.989-990.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schafer T. W., Pascale A., Shimonaski G., Came P. E. Evaluation of gentamicin for use in virology and tissue culture. Appl Microbiol. 1972 Mar;23(3):565–570. doi: 10.1128/am.23.3.565-570.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taplin D. The use of gentamicin in mycology media. J Invest Dermatol. 1965 Dec;45(6):549–550. doi: 10.1038/jid.1965.172. [DOI] [PubMed] [Google Scholar]
- Taplin D., Zaias N., Rebell G., Blank H. Isolation and recognition of dermatophytes on a new medium (DTM). Arch Dermatol. 1969 Feb;99(2):203–209. [PubMed] [Google Scholar]
- WEINSTEIN M. J., LUEDEMANN G. M., ODEN E. M., WAGMAN G. H., ROSSELET J. P., MARQUEZ J. A., CONIGLIO C. T., CHARNEY W., HERZOG H. L., BLACK J. GENTAMICIN, A NEW ANTIBIOTIC COMPLEX FROM MICROMONOSPORA. J Med Chem. 1963 Jul;6:463–464. doi: 10.1021/jm00340a034. [DOI] [PubMed] [Google Scholar]
- Waitz J. A., Weinstein M. J. Recent microbiological studies with gentamicin. J Infect Dis. 1969 Apr-May;119(4):355–360. doi: 10.1093/infdis/119.4-5.355. [DOI] [PubMed] [Google Scholar]