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Journal of Clinical Microbiology, September 2003, p. 4408-4410, Vol. 41, No. 9
0095-1137/03/$08.00+0 DOI: 10.1128/JCM.41.9.4408-4410.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
Chemically Defined Media for Growth of Haemophilus influenzae Strains
Hannah N. Coleman,
Dayle A. Daines, Justin Jarisch, and Arnold L. Smith*
Seattle Biomedical Research Institute, Seattle, Washington 98109
Received 16 February 2003/
Returned for modification 27 April 2003/
Accepted 9 June 2003
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ABSTRACT
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A chemically defined medium that supports the growth of both encapsulated and nontypeable Haemophilus influenzae strains in broth to densities that are
109 CFU/ml or on agar plates is described. The mean generation time of a panel of clinical isolates was comparable to that in rich, chemically undefined media (brain-heart infusion broth supplemented with heme and ß-NAD).
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TEXT
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Haemophilus influenzae is a fastidious, gram-negative coccus that inhabits the upper respiratory system of humans and has an obligate requirement for heme and ß-NAD for aerobic growth. Prior investigators studying Haemophilus influenzae sought a chemically defined medium to facilitate genetic and metabolic studies. Multiple defined media were devised for use with Rd derivatives of H. influenzae (2, 3, 4, 5, 6, 8, 13, 15), but these media would not support the growth of many nontypeable clinical isolates or encapsulated strains.
During the course of experiments studying the invasion of human cell lines by pathogenic H. influenzae, we found that RPMI medium-based tissue culture media appeared to support bacterial growth. Further studies led to the development of the chemically defined media described herein.
Table 1 describes the strains used in this study, which were stored at -70°C in 10% skim milk and were subcultured onto chocolate agar. One liter of chocolate agar was prepared by adding 36 g of GC base (catalog no. 228920; Difco, Detroit, Mich.) and 10 g of hemoglobin (catalog no. ZIZ392; BD Biosciences, Sparks, Md.) and autoclaving at 121°C at 15 lb/in2 for 20 min; after cooling to 55°C, 5,000 U of bacitracin and 10 ml of GCHI Rehydrating Solution (catalog no. 450411; Remel, Lenexa, Kans.) were added and the plates were poured. Supplemented brain-heart infusion (sBHI) agar was prepared by adding 37 g of BHI media (catalog no. 211059; BD Biosciences) and 15 g of BactoAgar (catalog no. 214530; BD Biosciences) to 1 liter of deionized water, autoclaving, cooling to 55°C, and adding 10 ml of ß-NAD and 10 ml of heme and L-histidine stock. The heme-histidine stock was prepared by dissolving 0.2 g of L-histidine (freebase; Sigma catalog no. H 8000) in 200 ml of deionized water and then adding 0.2 g of hemin HCl (catalog no. H 5533, bovine; Sigma) and 4 ml of 1 N NaOH and steaming over a boiling water bath for 5 to 10 min to solubilize the mixture. The solution was then cooled to room temperature, filter sterilized (0.2-µm pore size), and placed in a foil-covered bottle at 4°C. We found that the histidine decreased the rate at which the hemin precipitated from solution. ß-NAD+ stock was prepared by dissolving 100 mg of ß-NAD+ (catalog no. N 7004; Sigma) in 100 ml of deionized water, filter sterilizing (0.2-µm pore size), and storing at 4°C. sBHI broth was prepared without the agar.
Defined liquid medium was made with the following: 191 ml of RPMI 1640 with L-glutamine and 25 mM HEPES, pH 7.26 (catalog no. 61870036; InVitrogen), 2 ml of a 100 mM MEM sodium pyruvate solution (catalog no. 11360070; InVitrogen), 2 ml of ß-NAD+ stock, 4 ml of heme-L-histidine stock, 10 ml of a 2-mg/ml uracil solution (catalog no. U 0750; Sigma) dissolved in 0.1 N NaOH, and 20 ml of a 20-mg/ml inosine solution (catalog no. I 4125; Sigma) dissolved in deionized water and filter sterilized (0.2-µm pore size). The final pH of the liquid medium was 7.56. Where specified, NaHCO3 (2 g/liter) was added to the liquid medium.
Defined medium solidified with agar was made as follows: a package of RPMI 1640 powder containing L-glutamine and 25 mM HEPES (pH 7.26) (catalog no. 31800022; InVitrogen), which when reconstituted will make 1.0 liter of medium, was added to 334 ml of deionized H2O, 8.7 ml of 100 mM MEM sodium pyruvate solution (as described above), 8.7 ml of ß-NAD (1 mg/ml), 17.5 ml of heme-histidine stock, 44 ml of uracil (2 mg/ml), 87 ml of inosine (20 mg/ml), and 1 ml of bacitracin (5,000 U/ml). This 2x solution was adjusted to a pH of 7.18 to 7.2, filter sterilized (0.2-µm pore size), and warmed to 55°C. Fifteen grams of BactoAgar was added to 500 ml of deionized H2O, autoclaved for 20 min, and cooled to 55°C in a water bath. After the agar reached 55°C, the two solutions were mixed in a sterile fashion and were poured into 100-mm-diameter plates. Agar plates were incubated in either a 37°C Lab-Line Imperial II bacterial incubator or a NuAire 5% CO2, 37°C water-jacketed tissue culture incubator.
Growth curves were performed at 37°C by using 125-ml Erlenmeyer flasks with a starting volume of 15 ml of medium (sBHI broth or liquid defined medium) shaken at 200 rpm in room air or in 5% CO2. A 1-ml sample was taken from the flask at time zero and then at hourly intervals, and the A600 was measured in a Hitachi U2000 spectrophotometer. The flask contents were incubated in a New Brunswick floor shaker or on a platform shaker placed inside the tissue culture incubator. The defined media allowed growth of all 14 strains tested (Table 2). All strains grew to an A600 of >1.10 after 24 h of incubation, a turbidity equivalent to 107 to 109 CFU/ml. However, the final density of the Rd derivative R652 in defined media was about one-third that seen with sBHI broth: a mean of 3.5 x 109 versus 9.0 x 109 CFU/ml. Strains E1a and R2866 reached densities of 9.9 x 107 and 7.3 x 108 CFU/ml, respectively.
Representative H. influenzae strains, R652 (a reference strain), E1a (a prototypic type b), and R2866 (an invasive, unencapsulated strain), were chosen for further study. To estimate mean generation time, 0.1 ml was removed at the end of the lag phase and colony counts were repeated in duplicate at a minimum of three time points until the stationary phase was reached. With strains E1a and R2866, the mean generation time was slightly shorter in sBHI broth when the flasks were shaken in an environment of 5% CO2 than when they were shaken in room air (Table 3). The mean generation time of the prototypic strain R652 grown in defined medium and incubated in room air was 35.66 ± 9.43 min (n = 7), while in the CO2-enriched environment it was 31.36 ± 1.15 min (n = 3), differences that were not statistically significant.
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TABLE 3. Mean generation time of selected strains grown in sBHI broth or defined media when incubated in air or 5% CO2a
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We observed that, after 7 h of incubation, phenol red in the defined medium changed from pink to yellow and that there was a strain dependence and incubation environment effect on apparent acidification. To more precisely define the apparent acidification, we measured the pH of sBHI broth and defined media after 18 h of incubation in air and in a CO2-enriched environment. In general, there was acidification of sBHI broth in air and in 5% CO2. The same trend was seen with defined media, but there was less acidification in 5% CO2 (Table 4). Since defined media contain 23.8 mM NaHCO3, we added the same concentration to sBHI broth and measured the overnight growth and pH (Table 4). In general there were less acidification and less growth. Doubling the NaHCO3 concentration in defined media increased the final pH after incubation in room air but, as expected, had little effect in the 5% CO2 environment.
Since H. influenzae is a facultative anaerobe, we examined the growth of strains R652, E1a, and R2866 in liquid defined media under anaerobic conditions. Anaerobic incubations were performed by placing a 125-ml Erlenmeyer flask containing 15 ml of medium and a sterile stirring bar inside a Becton Dickinson anaerobic chamber by using the BBL GasPak Plus anaerobic system envelopes (catalog no. 271040; BD Biosciences) and BBL Dry Anaerobic Indicator strips (catalog no. 271051; BD Biosciences). The chamber was then placed on a magnetic stirrer inside a standard 37°C bacteriological incubator. The chamber was insulated from the surface of the stirrer by a 13-mm-thick styrofoam square. The cell density after overnight incubation was comparable to that observed in air; strain R652 reached 109 CFU/ml, E1a reached 9.9 x 107 CFU/ml, and R2866 reached 7.3 x 109 CFU/ml. Defined media solidified with agar supported growth of all the strains listed in Table 1 incubated in air or 5% CO2.
We conclude that this medium will facilitate metabolic studies of a wide variety of H. influenzae.
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ACKNOWLEDGMENTS
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This work was supported in part by grants AI 44002 and DC 005833 from the National Institutes of Health.
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FOOTNOTES
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* Corresponding author. Mailing address: Seattle Biomedical Research Institute, 4 Nickerson St., Suite 200, Seattle, WA 98109. Phone: (206) 284-8846. Fax: (206) 284-0313. E-mail: arnold.smith{at}sbri.org. 
Present address: Department of Molecular Microbiology & Immunology, School of Medicine, University of MissouriColumbia, Columbia, MO 65212. 
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REFERENCES
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- Barenkamp, S. J. 1986. Protection by serum antibodies in experimental nontypeable Haemophilus influenzae otitis media. Infect. Immun. 52:572-578.[Abstract/Free Full Text]
- Butler, L. O. 1962. A defined medium for Haemophilus influenzae and Haemophilus parainfluenzae. J. Gen. Microbiol. 27:51-60.
- Catlin, B. W. 1973. Nutritional profiles of Neisseria gonorrhoeae and Neisseria lactamica in chemically defined media and the use of growth requirements for gonococcal typing. J. Infect. Dis. 128:178-194.[Medline]
- Coulton, J. W., and J. C. S. Pang. 1983. Transport of hemin by Haemophilus influenzae type b. Curr. Microbiol. 9:93-98.
- Herriott, R. M., E. Y. Meyer, M. Vogt, and M. Modan. 1970. Defined medium for growth of Haemophilus influenzae. J. Bacteriol. 101:513-516.[Abstract/Free Full Text]
- Holt, L. B. 1961. The growth-factor requirements for Haemophilus influenzae. J. Gen. Microbiol. 27:317-322.
- Jiang, Z., N. Nagatat, E. Molina, L. O. Bakaletz, H. Hawkins, and J. A. Patel. 1999. Fimbria-mediated enhanced attachment of nontypeable Haemophilus influenzae to respiratory syncytial virus-infected respiratory epithelial cells. Infect. Immun. 67:187-192.[Abstract/Free Full Text]
- Klein, R. D., and G. H. Luginbuhl. 1979. Simplified media for the growth of Haemophilus influenzae from clinical and normal flora sources. J. Gen. Microbiol. 113:409-411.[Medline]
- Nizet, V., K. F. Colina, J. R. Almquist, C. R. Rubens, and A. L. Smith. 1998. A virulent nonencapsulated Haemophilus influenzae. J. Infect. Dis. 173:180-186.
- Setlow, J. K., D. C. Brown, M. E. Boling, A. Mattingly, and M. P. Gordon. 1968. Repair of deoxyribonucleic acid in Haemophilus influenzae. I. X-ray sensitivity of ultraviolet-sensitive mutants and their behavior as hosts to ultraviolet-irradiated bacteriophage and transforming deoxyribonucleic acid. J. Bacteriol. 95:546-558.[Abstract/Free Full Text]
- Smith, A. L., D. H. Smith, D. R. Averill, J. Marino, and E. R. Moxon. 1973. Production of Haemophilus influenzae b meningitis in infant rats by intraperitoneal inoculation. Infect. Immun. 8:278-290.[Abstract/Free Full Text]
- St. Geme, J. W., III, S. Falkow, and S. J. Barenkamp. 1993. High-molecular-weight proteins of nontypeable Haemophilus influenzae mediate attachment to human epithelial cells. Proc. Natl. Acad. Sci. USA 90:2875-2879.[Abstract/Free Full Text]
- Talmadge, M. B., and R. M. Herriott. 1960. A chemically defined medium for growth, transformation and isolation of nutritional mutants of Haemophilus influenzae. Biochem. Biophys. Res. Commun. 2:203-206.[CrossRef]
- Wilcox, K. W., and H. O. Smith. 1975. Isolation and characterization of mutants of Haemophilus influenzae deficient in an adenosine 5'-triphosphate-dependent deoxyribonuclease activity. J. Bacteriol. 122:443-453.[Abstract/Free Full Text]
- Wolin, H. L. 1963. Defined medium for Haemophilus influenzae. J. Bacteriol. 85:253-254.[Free Full Text]
Journal of Clinical Microbiology, September 2003, p. 4408-4410, Vol. 41, No. 9
0095-1137/03/$08.00+0 DOI: 10.1128/JCM.41.9.4408-4410.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
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