1. High G + C Gram-Positive Bacteria: The Acintobacteria
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Chapter 22
High G + C
Gram-Positive Bacteria:
The Acintobacteria

2. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
High G + C Bacteria
volume 4 of Bergey’s Manual of Systematic Bacteriology, 2nd Edition
Actinomycetes
gram-positive, aerobic bacteria that produce filamentous cells called hyphae and differentiate into asexual spores
adapt to climates similar to fungi

3. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.1

4. General Properties of the Actinomycetes
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
General Properties of the Actinomycetes
source of most currently used antibiotics
also produce metabolites that are anticancer, antihelminthic, and immunosuppressive
complex life cycle
most are not motile
motility is restricted to flagellated spores

5. Life Cycle of Actinomycetes
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Life Cycle of Actinomycetes
involves development of filamentous cells (hyphae) and spores
hyphae can form branching network
can grow on surface of substrate or into it to produce a substrate mycelium
some hyphae differentiate to form an aerial mycelium which extends above substratum
at this stage forms secondary metabolites, some of which are medically useful

6. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.2

7. Life Cycle of Actinomycetes…
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Life Cycle of Actinomycetes…
aerial mycelium
form exospores which are called sporangiospores if they are located in a sporangium
produced in response to nutrient deprivation
withstand desiccation but not heat resistant
spores dispersed by wind for new bacteria

8. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.3

9. Ecological Significance of Actinomycetes
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Ecological Significance of Actinomycetes
widely distributed in soil
play important role in mineralization of organic matter
most are free living, but a few are pathogens

10. Characteristics Used in Actinomycete Taxonomy
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Characteristics Used in Actinomycete Taxonomy
four major cell wall types based on peptidoglycan structure and sugar content other than N-acetylglucosamine and N-acetylmuramic acid

11. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.4

12. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Table 22.1

13. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.5

14. Phylum Actinobacteria
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Phylum Actinobacteria
16S rRNA evidence shows 1 class (Actinobacteria), five subclasses, six orders, 14 suborders, 44 families
consists of actinomycetes and their high G + C gram-positive relatives

15. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.6

16. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Table 22.2

17. Suborder Actinomycineae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Actinomycineae
one family with five genera
irregularly shaped, gram-positive rods
swelling, club shapes, or other deviations from normal rod morphology
aerobic or facultative metabolism

18. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Actinomyces
straight or slightly curved rods and slender filaments with true branching
may have swollen, clubbed, or clavate ends
facultative or obligate aerobes (require CO2)
peptidoglycan contains lysine and not diaminopimelic acid or glycine
normal inhabits of oral mucosa
cause of lumpy jaw in cattle
ocular infection, actinomycoses, and peridontal disease in humans

19. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.7

20. Suborder Micrococcineae Genus Micrococcus
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Micrococcineae Genus Micrococcus
aerobic, catalase-positive rods that occur in pairs, tetrads, or irregular clusters
usually nonmotile
often pigmented yellow, orange, or red
widespread in soil, water, and on human skin
does not undergo morphological differentiation

21. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.8

22. Genus Arthrobacter aerobic, catalase-positive rods, respiratory
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Arthrobacter
aerobic, catalase-positive rods, respiratory
lysine in peptidoglycan
rod-coccus growth cycle
exponential phase
irregular, branched rods
reproduce by snapping division
early stationary phase
begin to change to coccoid form
when transferred to fresh medium, coccoid cells produce outgrowths of actively growing rods

23. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.9

24. Genus Dermatophilus Dermatophilus (type IIIB)
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Dermatophilus
Dermatophilus (type IIIB)
form packets of motile spores with tufts of flagella
facultative anaerobes
parasites of mammals
cause streptothrichosis – skin infection

25. Suborder Corynebacterineae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Corynebacterineae
has seven families with many known genera such as
Corynebacterium
Mycobacterium
Nocardia

26. Genus Corynebacterium
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Corynebacterium
aerobic and facultative, catalase positive
straight to curved rods with tapered ends and club shaped
after snapping division bacteria often remain partially attached resulting in palisade arrangements of cells

27. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.10

28. Genus Corynebacterium
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Corynebacterium
form metachromatic granules
cell walls have meso-diaminopimelic acid
some are harmless soil and water saprophytes
many are animal and human pathogens
e.g., C. diphtheriae - diphtheria

29. Genus Mycobacterium in family Mycobacteriaceae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Mycobacterium
in family Mycobacteriaceae
straight or slightly curved rods that sometimes branch or form filaments
aerobic and catalase positive
filaments readily fragment into rods and coccoid bodies
very slow growing on culture media

30. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.11

31. Mycobacterial Cell Walls
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Mycobacterial Cell Walls
contain waxes with 60 to 90 carbon mycolic acids
cell wall surface
consists of the glycolipid trehalose dimycolate
once called cord factor
cell wall very hydrophobic
impenetrable by antibiotics
acid-fast
basic fuchsin dye cannot be removed from cell by acid alcohol treatment

32. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.12

33. Important Species of Mycobacterium
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Important Species of Mycobacterium
M. bovis
tuberculosis in cattle, humans
M. tuberculosis
tuberculosis in humans
M. avium complex (MAC)
various diseases
M. leprae
leprosy

34. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Nocardia
along with genus Rhodococcus make up the family Nocardiaceae
develop a substrate mycelium that readily breaks into rods and coccoid elements
some also form an aerial mycelium and conidia

35. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.13

36. Impact of Nocardia most are free-living saprophytes
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Impact of Nocardia
most are free-living saprophytes
can degrade many molecules
e.g., petroleum hydrocarbons, detergents, benzene
involved in biodegradation of rubber joints in water and sewage pipes
some are opportunistic pathogens causing nocardiosis
usually infect lungs; can infect central nervous system

37. Genus Rhodococcus widely distributed in soils and aquatic habitats
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Rhodococcus
widely distributed in soils and aquatic habitats
degrade an enormous variety of molecules such as
petroleum hydrocarbons, detergents, benzene, polychlorinated biphenyls (PCBs), various pesticides
may reduce sulfur from fuels and reduce air pollution from sulfur oxide emissions

38. Suborder Micromonosporineae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Micromonosporineae
only one family, Micromonosporaceae
extensive substrate mycelia
lack or have rudimentary aerial mycelia
sporangiospores motile or nonmotile
found in soil and aquatic habitats (especially freshwater)
soil dwellers play important roles in plant and animal decomposition
some produce antibiotics

39. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.14

40. Genus Propionibacterium
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Propionibacterium
found on skin and in digestive tract of animals
also in dairy products such as cheese
used in production of Swiss cheese
e.g., P. acne – involved in development of body odor and acne vulgaris

41. Suborder Streptomycineae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Streptomycineae
one family, three genera
aerial hyphae that divide in single plane to form chains of 3–50 nonmotile spores
all have type I cell wall
G+C DNA content is 69–78%
filaments grow by tip extension

42. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.15

43. Genus Streptomyces are 1 to 20% of culturable soil microbiota
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Streptomyces
are 1 to 20% of culturable soil microbiota
produce geosmin
volatile substance that is source of moist earth odor
important in mineralization process
aerobically degrade many resistant substances (e.g., pectin, lignin, and chitin)
produce vast array of antibiotics, other bioactive compounds, and antibiotic resistance genes
most are nonpathogenic saprophytes

44. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.16

45. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.17

46. Streptomyces coelicolor
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Streptomyces coelicolor
one of the largest bacterial genomes, 8.67 Mbp
largest number of genes (7,825)
65 RNA polymerase sigma subunits
80 two-component regulatory systems
genes for 18 additional secondary metabolites

47. Pathogenic Streptomycetes
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Pathogenic Streptomycetes
Streptomyces scabies
scab disease in potatoes and beets
Streptomyces somaliensis
actinomycetoma
infection of subcutaneous tissues in humans
leads to swelling, abscesses, and bone destruction

48. Suborder Streptosporangineae
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Streptosporangineae
three families, 16 genera
aerial mycelia bear pairs or short chains of spores
whole cell homogenates contain sugar madurose
Actinomadura associated with the disease acinomycetoma

49. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.18

50. Suborder Frankineae genera Frankia and Geodermatophilus
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Suborder Frankineae
genera Frankia and Geodermatophilus
both form multilocular sporangia characterized by clusters of spores
both have type III cell walls
Geodermatophilus
type IIIC, motile spores, aerobic
Frankia – type IIID, nonmotile spores, microaerophile, fixes nitrogen, symbiotic with nonleguminous plants

51. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.19

52. Genus Sporichthya Sporichthya lack substrate mycelium
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Genus Sporichthya
Sporichthya
lack substrate mycelium
use holdfasts to anchor to substratum
grow upward to form aerial mycelia
release motile, flagellated conidia in presence of water

53. Order Bifidobacteriales
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Order Bifidobacteriales
one family and ten genera
e.g., genera Falcivibrio and Gardnerella
found in human genitourinary tract
Gardnerella thought to be major cause of vaginitis
e.g., Bifidobacterium
nonsporing rods
found in mouth and intestinal tract of warm-blooded animals, in sewage, and in insects

54. e.g., Bifidobacterium bifidus
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
e.g., Bifidobacterium bifidus
pioneer colonizer of human intestinal tract
does not appear to be major cause of disease
probiotic agent

55. Copyright © The McGraw-Hill companies, Inc
Copyright © The McGraw-Hill companies, Inc. Permission required for reproduction or display.
Figure 22.20