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Category: Clinical Microbiology
Bacillus and Other Aerobic Endospore-Forming Bacteria * , Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap24-1.gif /docserver/preview/fulltext/10.1128/9781555816728/9781555814632_Chap24-2.gifAbstract:
This chapter discusses isolation and various tests for identification and detection of bacteria. The majority of aerobic endospore-forming species apparently have little or no pathogenic potential and are rarely associated with disease. Human anthrax has traditionally been classified as either (i) nonindustrial, resulting from close contact with infected animals or their carcasses after death from the disease, or (ii) industrial, as acquired by those employed in processing wool, hair, hides, bones, or other animal products. Clinical specimens for isolation of Bacillus species other than Bacillus anthracis can be handled safely on the open bench without special precautions. Sections of tissue, or any blood-stained material, should be collected, and spleen or lymph node specimens should be taken if the animal has been opened. The majority of work on molecular typing of Bacillus spp. has focused on members of the Bacillus cereus group due to their clinical importance and the value of genotyping for molecular epidemiology. Anthraxin does not contain highly specific anthrax antigens and relies on the fact that the only Bacillus species likely to proliferate within and throughout an animal is Bacillus anthracis. Low-level contamination of foodstuffs by aerobic endospore formers is commonplace, as is asymptomatic transient fecal carriage. Therefore, in foodborne illness investigations, qualitative isolation tests are insufficient.
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(a) Gram stain of B. anthracis, associated with a bioterrorism attack, showing grampositive rods in peripheral blood buffy coat following admission of patient; bar marker represents 3 μm. (Courtesy of H. Masur.) (b) DFA-stained preparation of B. anthracis using an antibody specific for the poly-γ-D-glutamic acid capsule. (c) India ink stain of B. anthracis incubated in horse blood. Clear zones surrounding the rods are due to the exclusion of the India ink by the capsule. (d) Spore-stained preparation of Bacillus cereus sporangia, viewed by bright-field microscopy. Spores are stained green, and vegetative cells are counterstained red. Bar marker represents 2 μm. (Photograph kindly provided by M. Rodríguez-Díaz.)
(a) Gram stain of B. anthracis, associated with a bioterrorism attack, showing grampositive rods in peripheral blood buffy coat following admission of patient; bar marker represents 3 μm. (Courtesy of H. Masur.) (b) DFA-stained preparation of B. anthracis using an antibody specific for the poly-γ-D-glutamic acid capsule. (c) India ink stain of B. anthracis incubated in horse blood. Clear zones surrounding the rods are due to the exclusion of the India ink by the capsule. (d) Spore-stained preparation of Bacillus cereus sporangia, viewed by bright-field microscopy. Spores are stained green, and vegetative cells are counterstained red. Bar marker represents 2 μm. (Photograph kindly provided by M. Rodríguez-Díaz.)
Photomicrographs of endospore-forming bacteria viewed by bright-field microscopy (a) and phase-contrast microscopy (b to l). Bar markers represent 2 μm. (a) B. anthracis, M'Fadyean stain showing capsulate rods in guinea pig blood smear; (b) B. cereus, broad cells with ellipsoidal, subterminal spores, not swelling the sporangia; (c) B. thuringiensis, broad cells with ellipsoidal, subterminal spores, not swelling the sporangia, and showing parasporal crystals of insecticidal toxin (arrows); (d) B. megaterium, broad cells with ellipsoidal and spherical, subterminal and terminal spores, not swelling the sporangia, and showing PHB inclusions (arrows); (e) B. subtilis, ellipsoidal, central and subterminal spores, not swelling the sporangia; (f) B. pumilus, slender cells with cylindrical, subterminal spores, not swelling the sporangia; (g) B. circulans, ellipsoidal, subterminal spores, swelling the sporangia; (h) Lysinibacillus sphaericus, spherical, terminal spores, swelling the sporangia; (i) Brevibacillus brevis, ellipsoidal, subterminal spores, one swelling its sporangium slightly; (j) Brevibacillus laterosporus, ellipsoidal, central spores with thickened rims on one side (arrow), swelling the sporangia; (k) Paenibacillus polymyxa, ellipsoidal, paracentral to subterminal spores, swelling the sporangia slightly; (l) Paenibacillus alvei, cells with tapered ends, ellipsoidal, paracentral to subterminal spores, not swelling the sporangium.
Photomicrographs of endospore-forming bacteria viewed by bright-field microscopy (a) and phase-contrast microscopy (b to l). Bar markers represent 2 μm. (a) B. anthracis, M'Fadyean stain showing capsulate rods in guinea pig blood smear; (b) B. cereus, broad cells with ellipsoidal, subterminal spores, not swelling the sporangia; (c) B. thuringiensis, broad cells with ellipsoidal, subterminal spores, not swelling the sporangia, and showing parasporal crystals of insecticidal toxin (arrows); (d) B. megaterium, broad cells with ellipsoidal and spherical, subterminal and terminal spores, not swelling the sporangia, and showing PHB inclusions (arrows); (e) B. subtilis, ellipsoidal, central and subterminal spores, not swelling the sporangia; (f) B. pumilus, slender cells with cylindrical, subterminal spores, not swelling the sporangia; (g) B. circulans, ellipsoidal, subterminal spores, swelling the sporangia; (h) Lysinibacillus sphaericus, spherical, terminal spores, swelling the sporangia; (i) Brevibacillus brevis, ellipsoidal, subterminal spores, one swelling its sporangium slightly; (j) Brevibacillus laterosporus, ellipsoidal, central spores with thickened rims on one side (arrow), swelling the sporangia; (k) Paenibacillus polymyxa, ellipsoidal, paracentral to subterminal spores, swelling the sporangia slightly; (l) Paenibacillus alvei, cells with tapered ends, ellipsoidal, paracentral to subterminal spores, not swelling the sporangium.
Colonies of endospore-forming bacteria on blood agar (a to i) and nutrient agar (j to l) after 24 to 36 h at 37°C. Bar markers represent 2 mm. (a) B. anthracis; (b) B. cereus; (c) B. thuringiensis; (d) B. megaterium; (e) B. pumilus; (f) Lysinibacillus sphaericus; (g) Brevibacillus brevis; (h) Brevibacillus laterosporus; (i) Paenibacillus polymyxa; (j) B. subtilis; (k) B. circulans; (l) Paenibacillus alvei.
Colonies of endospore-forming bacteria on blood agar (a to i) and nutrient agar (j to l) after 24 to 36 h at 37°C. Bar markers represent 2 mm. (a) B. anthracis; (b) B. cereus; (c) B. thuringiensis; (d) B. megaterium; (e) B. pumilus; (f) Lysinibacillus sphaericus; (g) Brevibacillus brevis; (h) Brevibacillus laterosporus; (i) Paenibacillus polymyxa; (j) B. subtilis; (k) B. circulans; (l) Paenibacillus alvei.
Characters for differentiating some species of Bacillus, Geobacillus, Paenibacillus, and Virgibacillus a
a Symbols and abbreviations: +, ≥85% positive; +/w, positive or weakly positive; w, weakly positive; (+), 75 to 84% positive; v, variable (26 to 74% positive); (–), 16 to 25% positive; –, 0 to 15% positive; –/w, negative or weakly positive.
b Arginine dihydrolase, indole production, gelatin hydrolysis, and nitrate reduction reactions was determined using tests in the API 20E strip (bioMérieux). Acid from carbohydrate reactions was determined using the API 50CHB System (bioMérieux).
c Reactions shown in brackets are for the biotype isolated particularly in connection with outbreaks of emetic-type food poisoning and for strains of serovars 1, 3, 5, and 8, which are commonly associated with such outbreaks.
d Spore shape: C, cylindrical; E, ellipsoidal; S, spherical. Spore position: C, central or paracentral; S, subterminal; T, terminal. The commonest shapes and positions are listed first, and those shown in parentheses are infrequently observed.
Characters for differentiating some species of Bacillus, Geobacillus, Paenibacillus, and Virgibacillus a
a Symbols and abbreviations: +, ≥85% positive; +/w, positive or weakly positive; w, weakly positive; (+), 75 to 84% positive; v, variable (26 to 74% positive); (–), 16 to 25% positive; –, 0 to 15% positive; –/w, negative or weakly positive.
b Arginine dihydrolase, indole production, gelatin hydrolysis, and nitrate reduction reactions was determined using tests in the API 20E strip (bioMérieux). Acid from carbohydrate reactions was determined using the API 50CHB System (bioMérieux).
c Reactions shown in brackets are for the biotype isolated particularly in connection with outbreaks of emetic-type food poisoning and for strains of serovars 1, 3, 5, and 8, which are commonly associated with such outbreaks.
d Spore shape: C, cylindrical; E, ellipsoidal; S, spherical. Spore position: C, central or paracentral; S, subterminal; T, terminal. The commonest shapes and positions are listed first, and those shown in parentheses are infrequently observed.
Characters for differentiating some species of Bacillus, Geobacillus, Paenibacillus, and Virgibacillus a
a Symbols and abbreviations: +, ≥85% positive; +/w, positive or weakly positive; w, weakly positive; (+), 75 to 84% positive; v, variable (26 to 74% positive); (–), 16 to 25% positive; –, 0 to 15% positive; –/w, negative or weakly positive.
b Arginine dihydrolase, indole production, gelatin hydrolysis, and nitrate reduction reactions was determined using tests in the API 20E strip (bioMérieux). Acid from carbohydrate reactions was determined using the API 50CHB System (bioMérieux).
c Reactions shown in brackets are for the biotype isolated particularly in connection with outbreaks of emetic-type food poisoning and for strains of serovars 1, 3, 5, and 8, which are commonly associated with such outbreaks.
d Spore shape: C, cylindrical; E, ellipsoidal; S, spherical. Spore position: C, central or paracentral; S, subterminal; T, terminal. The commonest shapes and positions are listed first, and those shown in parentheses are infrequently observed.
Characters for differentiating some species of Bacillus, Geobacillus, Paenibacillus, and Virgibacillus a
a Symbols and abbreviations: +, ≥85% positive; +/w, positive or weakly positive; w, weakly positive; (+), 75 to 84% positive; v, variable (26 to 74% positive); (–), 16 to 25% positive; –, 0 to 15% positive; –/w, negative or weakly positive.
b Arginine dihydrolase, indole production, gelatin hydrolysis, and nitrate reduction reactions was determined using tests in the API 20E strip (bioMérieux). Acid from carbohydrate reactions was determined using the API 50CHB System (bioMérieux).
c Reactions shown in brackets are for the biotype isolated particularly in connection with outbreaks of emetic-type food poisoning and for strains of serovars 1, 3, 5, and 8, which are commonly associated with such outbreaks.
d Spore shape: C, cylindrical; E, ellipsoidal; S, spherical. Spore position: C, central or paracentral; S, subterminal; T, terminal. The commonest shapes and positions are listed first, and those shown in parentheses are infrequently observed.