• View in gallery

    Representative growth of Burkholderia pseudomallei (A) plate view and (C) colony view, and of Burkholderia mallei (B) plate view and (D) colony view, on Pseudomonas cepacia (PC) agar at 72 hours incubation at 30°C.

  • 1

    Rotz LD, Khan AS, Lillibridge SR, Ostroff SM, Hughes JM, 2002. Public health assessment of potential bioterrorism agents. Emerg Infect Dis 8 :225–230.

    • Search Google Scholar
    • Export Citation
  • 2

    Ashdown LR, 1979. An improved screening technique for the isolation of Pseudomonas pseudomallei from clinical specimens. Pathology 11 :293–297.

    • Search Google Scholar
    • Export Citation
  • 3

    Wuthiekanun V, Dance DAB, Wattanagoon Y, Supputtamongkol Y, Chaowagul W, White NJ, 1990. The use of selective media for the isolation of Pseudomonas pseudomallei in clinical practice. J Med Microbiol 33 :121–126.

    • Search Google Scholar
    • Export Citation
  • 4

    Peacock SJ, Chieng G, Cheng AC, Dance DAB, Amornchai P, Wongsuvan G, Teerawattanasook N, Chierakul W, Day NPJ, Wuthiekanun V, 2005. Comparison of Ashdown’s medium, Burkholderia cepacia medium, and Burkholderia pseudomallei selective agar for the clinical isolation of Burkholderia pseudomallei. J Clin Microbiol 43 :5359–5361.

    • Search Google Scholar
    • Export Citation
  • 5

    Ashdown LR, Clarke SG, 1992. Evaluation of culture techniques for isolation of Pseudomonas pseudomallei from soil. Appl Environ Microbiol 58 :4011–4015.

    • Search Google Scholar
    • Export Citation
  • 6

    Francis A, Aiyar S, Yean CY, Naing L, Ravichandran M, 2006. An improved selective and differential medium for the isolation of Burkholderia pseudomallei from clinical specimens. Diagn Microbiol Infect Dis 55 :95–99.

    • Search Google Scholar
    • Export Citation
  • 7

    Howard K, Inglis TJJ, 2003. Novel selective medium for isolation of Burkholderia pseudomallei. J Clin Microbiol 41 :3312–3316.

  • 8

    Henry D, Campbell M, McGimpsey C, Clarke A, Louden L, Burns JL, Roe MH, Vandamme P, Speert D, 1999. Comparison of isolation media for the recovery of Burkholderia cepacia complex from respiratory secretions of patients with cystic fibrosis. J Clin Microbiol 37 :1004–1007.

    • Search Google Scholar
    • Export Citation
  • 9

    Henry DA, Campbell ME, LiPuma JJ, Speert DP, 1997. Identification of Burkholderia cepacia isolates from patients with cystic fibrosis and use of a simple new selective medium. J Clin Microbiol 35 :614–619.

    • Search Google Scholar
    • Export Citation
  • 10

    Welch DF, Muszynski MJ, Pai CH, Marcon MJ, Hribar MM, Gilligan PH, Matsen JM, Ahlin PA, Hilman BC, Chartard SA, 1987. Selective and differential medium for recovery of Pseudomonas cepacia from the respiratory tract of patients with cystic fibrosis. J Clin Microbiol 25 :1730–1734.

    • Search Google Scholar
    • Export Citation
  • 11

    Gilligan PH, Gage PA, Bradshaw LM, Schidlow DV, DeCicco BT, 1985. Isolation medium for the recovery of Pseudomonas cepacia from respiratory secretions of patients with cystic fibrosis. J Clin Microbiol 22 :5–8.

    • Search Google Scholar
    • Export Citation
  • 12

    Weyant RS, Moss CW, Weaver RE, Hollis DG, Jordan JG, Cook EC, Daneshvar MI, 1996. Identification of Unusual Pathogenic Gram-Negative Aerobic and Facultatively Anaerobic Bacteria. Second edition. Baltimore, MD: Williams & Wilkins.

  • 13

    Gee JE, Sacchi CT, Glass MB, De BK, Weyant RS, Levett PN, Whitney AM, Hoffmaster AR, Popovic T, 2003. Use of 16S rRNA gene sequencing for rapid identification and differentiation of Burkholderia pseudomallei and B. mallei. J Clin Microbiol 41 :4647–4654.

    • Search Google Scholar
    • Export Citation
  • 14

    Chantratita N, Wuthiekanun V, Bonbumrung K, Tiyawisutsri R, Vesaratchavest M, Limmathurotsakul D, Chierakul W, White NJ, Day NPJ, Peacock SJ, 2007. Biological relevance of colony morphology and phenotypic switching by Burkholderia pseudomallei. J Bacteriol 189 :807–817.

    • Search Google Scholar
    • Export Citation
  • 15

    Brett PJ, DeShazer D, Woods DE, 1998. Burkholderia thailandensis sp. nov., a Burkholderia pseudomallei-like species. Int J Syst Bacteriol 48 :317–320.

    • Search Google Scholar
    • Export Citation
  • 16

    Glass MB, Steigerwalt AG, Jordon JG, Wilkins PP, Gee JE, 2006. Burkholderia oklahomensis sp. nov., a Burkholderia pseudomallei-like species formerly known as the Oklahoma strain of Pseudomonas pseudomallei. Int J Syst Evol Microbiol 44 :2171–2176.

    • Search Google Scholar
    • Export Citation
  • 17

    Smith MD, Angus BJ, Wuthiekanun V, White NJ, 1997. Arabinose assimilation defines a nonvirulent biotype of Burkholderia pseudomallei. Infect Immun 65 :4319–4321.

    • Search Google Scholar
    • Export Citation
  • 18

    Godoy D, Randle F, Simpson AJ, Aanensen DM, Pitt TL, Kinoshita R, Spratt BG, 2003. Multilocus sequence typing and evolutionary relationships among the causative agents of melioidosis and glanders, Burkholderia pseudomallei and Burkholderia mallei. J Clin Microbiol 41 :2068–2079.

    • Search Google Scholar
    • Export Citation
  • 19

    Payne GW, Vandamme P, Morgan SH, LiPuma JJ, Coenye T, Weightman AJ, Jones TH, Mahenthiralingam E, 2005. Development of a recA gene-based identification approach for the entire Burkholderia genus. Appl Environ Microbiol 71 :3917–3927.

    • Search Google Scholar
    • Export Citation

 

 

 

 

 

Comparison of Four Selective Media for the Isolation of Burkholderia mallei and Burkholderia pseudomallei

View More View Less
  • 1 Bacterial Zoonoses Branch, Division of Foodborne, Bacterial, and Mycotic Diseases, National Center for Zoonotic, Vector-borne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia

Currently there are no commercially available selective media indicated for the isolation of Burkholderia mallei and Burkholderia pseudomallei. Ashdown’s agar, a custom selective medium for isolation of B. pseudomallei, is well described in the literature but unavailable commercially. Three commercially available media, Burkholderia cepacia selective agar (BCSA), oxidative-fermentative-polymyxin B-bacitracin-lactose (OFPBL) agar, and Pseudomonas cepacia (PC) agar are recommended for isolation of B. cepacia from respiratory secretions of cystic fibrosis patients. We evaluated the sensitivity and selectivity of these four media using 20 B. mallei, 20 B. pseudomallei, 20 Burkholderia spp., and 15 diagnostically challenging organisms. Ashdown’s agar was the most sensitive medium for the isolation of B. pseudomallei, but it was unable to support growth of B. mallei. Pseudomonas cepacia agar was highly sensitive and selective for both organisms. In non-endemic areas, we suggest the use of the commercially available PC agar for the isolation of B. mallei and B. pseudomallei.

INTRODUCTION

Burkholderia mallei and Burkholderia pseudomallei, the bacteria that cause the diseases glanders and melioidosis, respectively, are classified as category B select agents in the United States because of concerns regarding both their dissemination potential and public health impact if used for bioterrorism.1 For bioterrorism preparedness, clinical laboratories need to be able to detect these organisms in a variety of samples. To enhance the recovery of bacterial organisms from clinical samples that contain extensive normal microbiota, selective media greatly increase the chances of isolation and help to prevent overgrowth from other organisms, which can obscure or inhibit growth. Currently, there are no commercially available selective media specifically produced for the isolation and identification of B. mallei or B. pseudomallei. However, in the literature, Ashdown described a selective medium for the isolation of B. pseudomallei, referred to commonly as Ashdown’s agar, that has been used extensively and is prepared in-house for use by laboratories where melioidosis is endemic. 2,3 Other selective media are available commercially but are intended for the isolation of the closely related Burkholderia cepacia from respiratory secretions of patients with cystic fibrosis. These media include B. cepacia selective agar (BCSA), oxidative-fermentative-polymyxin B-bacitracin-lactose (OFPBL) agar, and Pseudomonas cepacia (PC) agar.

Ashdown’s agar (ASH) contains glycerol, crystal violet, neutral red, and gentamicin to significantly increase the recovery of B. pseudomallei from sites or specimens with high microbial diversity.3 Burkholderia pseudomallei characteristically exhibit a wrinkled, rough morphology with dark purple pigment. Ashdown’s agar is currently used in countries where melioidosis is endemic and allows for a presumptive identification in 2 to 4 days.4 Disadvantages of ASH include inhibition of some mucoid strains of B. pseudomallei, inability to differentiate B. pseudomallei from some B. cepacia strains that appear wrinkled, and selectivity against B. mallei because it contains gentamicin.57

The BCSA uses crystal violet, phenol red, lactose, sucrose, polymyxin B, gentamicin, and vancomycin for the selective and differential culture of isolates within or belonging to the B. cepacia complex. This medium permits heavier growth of B. cepacia after 24 hours of culture when compared with OFPBL or PC.8 However, it may not be possible to distinguish B. cepacia from B. pseudomallei because of variable colony morphologies. With clinical samples BCSA had higher colony counts and was shown to be as selective as ASH and thus has been recommended as an acceptable substitute for ASH in non-endemic areas.4 However, like ASH, growth of B. mallei strains will be inhibited by gentamicin.

The OFPBL is an OF (oxidation-fermentation) basal medium containing polymyxin B, bacitracin, and lactose and allows for selective and differential characterization of B. cepacia. Based on the formulation, OFPBL should support the growth of both B. mallei and B. pseudomallei. However, the selectivity of this medium is a problem, as seen when culturing specimens from cystic fibrosis patients; some strains of yeast, Serratia spp., Proteus spp., Flavobacterium spp., Stenotrophomonas maltophilia, and Pseudomonas spp. have grown on OFPBL.810

The PC agar contains crystal violet, bile salts, ticarcillin, and polymyxin B, which inhibit the growth of Pseudomonas aeruginosa and other respiratory pathogens. 11 Prior experience with this agar has demonstrated good growth with both B. mallei and B. pseudomallei strains. However, other organisms have demonstrated growth similar to B. cepacia and a small percentage of B. cepacia strains are inhibited. 8,11

We evaluated these four selective media for the isolation of both B. mallei and B. pseudomallei looking at sensitivity and selectivity using a well characterized, diverse set of 20 B. pseudomallei, 20 B. mallei, 20 Burkholderia spp., and 15 closely related species. This is the first study to compare media for the selective isolation of B. mallei. In addition, some of the closely related Burkholderia species have recently been described and have not been evaluated in previous studies. Our aim was to determine whether a single commercially available selective medium could be used for isolation of B. pseudomallei and B. mallei from non-sterile sites. This would help to avoid the preparation and quality control of a custom medium by laboratories that rarely encounter these bacteria, especially in regions where these diseases are not endemic.

MATERIALS AND METHODS

Twenty B. mallei, 20 B. pseudomallei, 20 Burkholderia spp., and 15 diagnostically challenging or closely related organisms (Table 1) were recovered from −70°C freezer stocks of our culture collection and subcultured twice onto trypticase soy agar with 5% sheep blood (BBL Microbiology Systems, Cockeysville, MD) before plating on ASH (prepared in-house according to author’s instructions),2 BCSA (Remel, Lenexa, KS), OFPBL (Remel, Lenexa, KS), and PC (Remel, Lenexa, KS). The B. cepacia type strain ATCC 25416 was inoculated as a control with each set of agar plates. Identification of the strain collection, except in the case of type strains, was carried out using a standard battery of biochemical tests and 16S ribosomal RNA (rRNA) gene sequencing. 12,13 The ASH and BCSA plates were incubated at 37°C and PC and OFPBL plates were incubated at 30°C as per manufacturer’s instructions or, as in the case of ASH, per author recommendation.2 Plates were observed and photographed at 24, 48, 72, and 96 hours, and 1 week. Positive growth was determined by the ability of the organism to grow away from the original streak. Characteristic growth was determined by the ability of the organism to demonstrate expected or uniform morphology. Results were formulated based upon the recommended incubation time points determined by either the manufacturer or as recommended in the literature: 48 hours for OFPBL, 72 hours for BCSA, and PC, and 96 hours for ASH. All work was performed using Biosafety Level 3 (BSL-3) practices, containment, and facilities.

To evaluate the ability of PC agar to select against normal microbiota in clinical samples, swabbing of the pharynx and tonsillar facues was performed on four volunteers. Trypticase soy agar with 5% sheep blood (SBA) (BBL Microbiology Systems, Cockeysville, MD) and PC agar plates were inoculated with a swab from each patient. Plates were incubated at 30°C and observed at 72 hours.

RESULTS

Sensitivity was determined by demonstration of characteristic growth at the recommended incubation length. On ASH, all 20 B. pseudomallei strains (100%) demonstrated either the characteristic purple wrinkled (80%) or a smooth “donut” shaped (20%) appearance (Table 2). No B. mallei strains grew on the ASH plates. Of the 13 Burkholderia spp. able to grow on ASH, only Burkholderia oklahomensis demonstrated the characteristic wrinkled appearance. Of the 10 diagnostically challenging organisms that were capable of growth on ASH, none exhibited characteristic growth.

Overall, 14 strains of B. pseudomallei (70%) demonstrated two common morphologies on BCSA. Eight B. pseudomallei strains (40%) showed an agar color change to yellow with growth of circular, smooth, convex, gray to white, and metallic colonies, whereas six (30%) showed the same yellow agar change but with circular, wrinkled, and blue to gray metallic colonies. No B. mallei strains grew on BCSA. Of the 14 Burkholderia spp. that were capable of growth on BCSA, only Burkholderia thailandensis demonstrated growth that was similar to the B. pseudomallei strains, exhibiting yellow color change of the agar with growth of circular, smooth, convex, and white metallic colonies. Only 5 diagnostically challenging strains were able to grow on BSCA, none of which shared any similar morphology to B. pseudomallei.

On OFPBL, 18 B. pseudomallei strains (90%) shared a common morphology of circular, smooth, entire, convex, and yellow to translucent colonies with an agar color change to yellow. However, 25% of Burkholderia spp. and 7% of diagnostically challenging strains showed those same characteristics. Eleven B. mallei strains were able to grow on OFPBL with either no agar color change or a change to yellow, with growth of circular, translucent, and pinpoint-sized colonies. One B.cepacia strain shared the same morphology.

On PC, 19 B. pseudomallei strains (95%) shared a common morphology that was distinct from strains of the B. cepacia complex for which this medium was designed. All 19 strains grew circular, white to yellow metallic colonies and changed the agar color to pink. The one remaining strain, PHLS 216, was mucoid with white colonies and no metallic sheen. Of the 12 Burkholderia spp. capable of growth on PC, only two (10%), B. oklahomensis and B. thailadensis, demonstrated a similar appearance. Fifteen B. mallei (75%) demonstrated an agar color change to pink with circular, smooth, and white to translucent colonies, all smaller than 1 mm (Figure 1). Of the five remaining B. mallei, NCTC 10247 grew but did not change the agar color and four did not grow at all (ATCC 15310, India 65-503, KC1092, and NCTC 10248). One B. cepacia strain (5%) resembled the growth of B. mallei. Of the 7 diagnostically challenging organisms that grew on PC, only two, Stenotrophomonas maltophilia and Ralstonia pickettii, demonstrated similar growth to B. mallei.

Selectivity was defined as the percentage of strains that did not grow. For non-B. pseudomallei and B. mallei strains of Burkholderia, selectivity was calculated to 34% for ASH, 46% for BCSA, 34% for OFPBL, and 46% for PC (Table 3). For non-Burkholderia spp., selectivity was 33% for ASH, 67% for BCSA, 47% for OFPBL, and 53% for PC. Although inhibition generally varied from medium to medium, strains that did not grow on any of the four media included B. mallei ATCC 15310, B. cepacia H444, B. rhizoxinica, Chromobacterium violaceum, Pseudomonas mendocina, and Staphylococcus aureus.

All four SBA plates inoculated with throat swabs from human volunteers were completely overgrown. No colony forming units (cfu) were observed on the PC agar inoculated with throat swabs after 72 hours or at one week of incubation.

DISCUSSION

The most sensitive medium for the growth of B. pseudomallei was ASH, with all 20 strains showing a characteristic growth appearance. This was not surprising considering reports from previous studies and long-standing use in the literature.24,14 The results of growth on PC, seen with 95% and 75% sensitivities for the growth of B. pseudomallei and B. mallei, respectively, have established it as a commercial selective agar that may be suitable for both these organisms. The PC was substantially more sensitive for B. mallei than the other media. This selective medium can serve as a suitable substitute for ASH in laboratories located in non-endemic areas or that are limited to commercially available products. For laboratories unaccustomed to routinely working with these organisms, having to purchase and stock only one medium that serves many purposes is time- and cost-effective. Additionally, PC agar was effective at selecting against throat microbiota as compared with a non-selective medium. The BCSA did not support the growth of B. mallei and had a lower sensitivity than either ASH or PC. The OFPBL did not support development of characteristic colony appearance in the recommended incubation length of 48 hours. Lengthening the incubation to 96 hours or 1 week enhanced the morphology of all strains and increased sensitivity.

Burkholderia oklahomensis and B. thailandensis share morphologic characteristics similar to B. pseudomallei on all four selective media. This result is not unexpected, as both organisms were previously misclassified as B. pseudomallei or B. pseudomallei-like strains.15,16 To date there are very few reports of disease caused by B. oklahomensis and B. thailandensis, so it is not clear how similar their clinical presentations might be to melioidosis. Burkholderia oklahomensis can be differentiated from B. pseudomallei using molecular testing such as Multilocus sequence typing (MLST) or 16S rRNA gene sequencing. 16 Burkholderia thailandensis strains, common to soil and water in Thailand, can be easily distinguished from B. pseudomallei by assimilation of arabinose and other molecular methods, such as MLST, 16S, and recA gene sequencing. 13,1719

The BCSA and PC were the most selective media against strains of Burkholderia that were not B. pseudomallei or B. mallei. The high selectivity and sensitivity of PC for the isolation of B. mallei and B. pseudomallei make this medium ideal for use with non-sterile specimens in suspected cases of melioidosis or glanders. Inoculation of non-selective media with throat swabs resulted in overgrowth, whereas PC agar successfully inhibited all growth of the normal microbiota for four separate volunteers. However, we will continue to evaluate these media for effectiveness against other clinical specimens that are routinely positive for B. mallei and B. pseudomallei. Growth on PC can be read at 72 hours, a day earlier than ASH, helping the investigator to reduce the time required for identification. When B. pseudomallei or B. mallei are suspected, all work should be performed in a BSL-3 setting. A further evaluation comparing PC and ASH in an endemic setting would be most valuable. On the basis of these results, we recommend the use of PC agar for the selective isolation of B. mallei and B. pseudomallei outside of melioidosis endemic areas, where preparation of custom media for isolation of rarely occurring organisms is not indicated.

Table 1

Designations of strains used in study*

Table 1 Table 1
Table 2

Sensitivity as determined by characteristic growth*

Table 2
Table 3

Selectivity as defined as the percentage of strains that did not grow*

Table 3
Figure 1.
Figure 1.

Representative growth of Burkholderia pseudomallei (A) plate view and (C) colony view, and of Burkholderia mallei (B) plate view and (D) colony view, on Pseudomonas cepacia (PC) agar at 72 hours incubation at 30°C.

Citation: The American Journal of Tropical Medicine and Hygiene Am J Trop Med Hyg 80, 6; 10.4269/ajtmh.2009.80.1023

*

Address correspondence to Mindy B. Glass, Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne and Enteric Diseases, Division of Foodborne, Bacterial and Mycotic Diseases, Bacterial Zoonoses Branch, 1600 Clifton Road, MS G-34, Atlanta, GA 30333. E-mail: mglass@cdc.gov

Authors’ addresses: Mindy B. Glass, Cari A. Beesley, Patricia P. Wilkins, and Alex R. Hoffmaster, Centers for Disease Control and Prevention, National Center for Zoonotic, Vector-borne and Enteric Diseases, Division of Foodborne, Bacterial and Mycotic Diseases, Bacterial Zoonoses Branch, 1600 Clifton Road, MS G-34, Atlanta, GA 30333, Tel: 404-639-4055, Fax: 404-639-3023, E-mail: mglass@cdc.gov.

Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

REFERENCES

  • 1

    Rotz LD, Khan AS, Lillibridge SR, Ostroff SM, Hughes JM, 2002. Public health assessment of potential bioterrorism agents. Emerg Infect Dis 8 :225–230.

    • Search Google Scholar
    • Export Citation
  • 2

    Ashdown LR, 1979. An improved screening technique for the isolation of Pseudomonas pseudomallei from clinical specimens. Pathology 11 :293–297.

    • Search Google Scholar
    • Export Citation
  • 3

    Wuthiekanun V, Dance DAB, Wattanagoon Y, Supputtamongkol Y, Chaowagul W, White NJ, 1990. The use of selective media for the isolation of Pseudomonas pseudomallei in clinical practice. J Med Microbiol 33 :121–126.

    • Search Google Scholar
    • Export Citation
  • 4

    Peacock SJ, Chieng G, Cheng AC, Dance DAB, Amornchai P, Wongsuvan G, Teerawattanasook N, Chierakul W, Day NPJ, Wuthiekanun V, 2005. Comparison of Ashdown’s medium, Burkholderia cepacia medium, and Burkholderia pseudomallei selective agar for the clinical isolation of Burkholderia pseudomallei. J Clin Microbiol 43 :5359–5361.

    • Search Google Scholar
    • Export Citation
  • 5

    Ashdown LR, Clarke SG, 1992. Evaluation of culture techniques for isolation of Pseudomonas pseudomallei from soil. Appl Environ Microbiol 58 :4011–4015.

    • Search Google Scholar
    • Export Citation
  • 6

    Francis A, Aiyar S, Yean CY, Naing L, Ravichandran M, 2006. An improved selective and differential medium for the isolation of Burkholderia pseudomallei from clinical specimens. Diagn Microbiol Infect Dis 55 :95–99.

    • Search Google Scholar
    • Export Citation
  • 7

    Howard K, Inglis TJJ, 2003. Novel selective medium for isolation of Burkholderia pseudomallei. J Clin Microbiol 41 :3312–3316.

  • 8

    Henry D, Campbell M, McGimpsey C, Clarke A, Louden L, Burns JL, Roe MH, Vandamme P, Speert D, 1999. Comparison of isolation media for the recovery of Burkholderia cepacia complex from respiratory secretions of patients with cystic fibrosis. J Clin Microbiol 37 :1004–1007.

    • Search Google Scholar
    • Export Citation
  • 9

    Henry DA, Campbell ME, LiPuma JJ, Speert DP, 1997. Identification of Burkholderia cepacia isolates from patients with cystic fibrosis and use of a simple new selective medium. J Clin Microbiol 35 :614–619.

    • Search Google Scholar
    • Export Citation
  • 10

    Welch DF, Muszynski MJ, Pai CH, Marcon MJ, Hribar MM, Gilligan PH, Matsen JM, Ahlin PA, Hilman BC, Chartard SA, 1987. Selective and differential medium for recovery of Pseudomonas cepacia from the respiratory tract of patients with cystic fibrosis. J Clin Microbiol 25 :1730–1734.

    • Search Google Scholar
    • Export Citation
  • 11

    Gilligan PH, Gage PA, Bradshaw LM, Schidlow DV, DeCicco BT, 1985. Isolation medium for the recovery of Pseudomonas cepacia from respiratory secretions of patients with cystic fibrosis. J Clin Microbiol 22 :5–8.

    • Search Google Scholar
    • Export Citation
  • 12

    Weyant RS, Moss CW, Weaver RE, Hollis DG, Jordan JG, Cook EC, Daneshvar MI, 1996. Identification of Unusual Pathogenic Gram-Negative Aerobic and Facultatively Anaerobic Bacteria. Second edition. Baltimore, MD: Williams & Wilkins.

  • 13

    Gee JE, Sacchi CT, Glass MB, De BK, Weyant RS, Levett PN, Whitney AM, Hoffmaster AR, Popovic T, 2003. Use of 16S rRNA gene sequencing for rapid identification and differentiation of Burkholderia pseudomallei and B. mallei. J Clin Microbiol 41 :4647–4654.

    • Search Google Scholar
    • Export Citation
  • 14

    Chantratita N, Wuthiekanun V, Bonbumrung K, Tiyawisutsri R, Vesaratchavest M, Limmathurotsakul D, Chierakul W, White NJ, Day NPJ, Peacock SJ, 2007. Biological relevance of colony morphology and phenotypic switching by Burkholderia pseudomallei. J Bacteriol 189 :807–817.

    • Search Google Scholar
    • Export Citation
  • 15

    Brett PJ, DeShazer D, Woods DE, 1998. Burkholderia thailandensis sp. nov., a Burkholderia pseudomallei-like species. Int J Syst Bacteriol 48 :317–320.

    • Search Google Scholar
    • Export Citation
  • 16

    Glass MB, Steigerwalt AG, Jordon JG, Wilkins PP, Gee JE, 2006. Burkholderia oklahomensis sp. nov., a Burkholderia pseudomallei-like species formerly known as the Oklahoma strain of Pseudomonas pseudomallei. Int J Syst Evol Microbiol 44 :2171–2176.

    • Search Google Scholar
    • Export Citation
  • 17

    Smith MD, Angus BJ, Wuthiekanun V, White NJ, 1997. Arabinose assimilation defines a nonvirulent biotype of Burkholderia pseudomallei. Infect Immun 65 :4319–4321.

    • Search Google Scholar
    • Export Citation
  • 18

    Godoy D, Randle F, Simpson AJ, Aanensen DM, Pitt TL, Kinoshita R, Spratt BG, 2003. Multilocus sequence typing and evolutionary relationships among the causative agents of melioidosis and glanders, Burkholderia pseudomallei and Burkholderia mallei. J Clin Microbiol 41 :2068–2079.

    • Search Google Scholar
    • Export Citation
  • 19

    Payne GW, Vandamme P, Morgan SH, LiPuma JJ, Coenye T, Weightman AJ, Jones TH, Mahenthiralingam E, 2005. Development of a recA gene-based identification approach for the entire Burkholderia genus. Appl Environ Microbiol 71 :3917–3927.

    • Search Google Scholar
    • Export Citation
Save