11-1

03-22-12Medically important bacteria

11-2

Chemoorganotrophs (fermentation)

• Variety of end products (acids and gases)

• Ex. Clostridium species - form endospores

• Ex. Lactic acid bacteria (Lactobacillus, Streptococcus, Enterococcus)

11-3

11-4 Clostridium tetani (23.8)

11-5

Muscular spasms in an individual with tetanus (23.7)

11-6

11-7

Streptococcus pyogenes stainedwith fluorescent antibody (24.2)

11-8

Streptococcus pyogenes growing on blood agar (22.6)

11-9

11-10

Lactobacillus species (11.3)

Produce lactic acid; aerotolerant anaerobe, obligate fermenter.Metabolizes glycogen in the vagina, low pH protects against infection

11-11

Aerobic Chemoorganotrophs

• Obligate aerobes

• Facultative anaerobes

11-12

Obligate Aerobes

• Large variety of bacteria

• Ex. Mycrococcus species

• Ex. Mycobacterium species

• Ex. Pseudomonas species

11-13

Micrococcus luteus (11.11)

Airborne, common contaminant in petri dishes,recognized by yellow pigments

11-14

Pseudomonas species (11.12)

Pigmented Gram-negative rods, diverse biochemical capabilities, important in bioremediation, P. aeruginosa is a common opportunistic pathogen in hospitals

11-15

Mycobacterium tuberculosis in sputum from a tuberculosis patient (24.17)

11-16

11-17

Stained lungtissue showing a tubercule(a granuloma containinginflammatory cells) andlung X-ray from atuberculosispatient (24.18)

11-18

Facultative Anaerobes

• Ex. Corynebacterium species

• Ex. Enterobacteriaceae family

11-19

Corynebacterium (11.13)

Gram-positive pleomorphic rods (coryneforms) C. diptheriae causes diphtheria

11-20

Enterobacteriaceae (11.14)

Enterobacteria, Gram-negative rods, reside in intestinal tract Enterobacter, Klebsiella, Proteus are part of normal flora, Shigella, Salmonella, some E. coli stains, Yersina pestis cause disease

E. coli O157:H7 inuncooked burgerscaused gastroenteritisepidemic in WashingtonState in 1993

11-21

Thriving in Terrestrial Environments

11-22

Endospore – formers (11.15)

Bacillus anthracis Clostridium tetani

Gram-positive rods

11-23

Aquatic Bacteria

Vibrio cholerae - cholera

Vibrio parahaemolyticus - gastrointestinal disease

Legionella pneumophila - Legionaire’s diseaseGram-negative aerobes that use aa’s

Leptospira interrogans - leptospirosis

Treponema pallidum – syphilis

Borrelia burgdorferi - Lyme disease

11-24

Legionella pneumophila, stained with a fluorescent antibody (24.20)

11-25

Scanning EM of Vibrio cholerae attached to intestinal mucosa using pili (25.12)

11-26 Mode of action of cholera toxin (25.13)

11-27

11-28

Spirochetes (11.26)

11-29

Syphilitic chancre, the entry point forTreponema pallidum (22.12)

11-30

11-31 Scanning EM of Borrelia burgdorferi (22.13)

11-32

11-33

Life cycle of theDeer Tick (22.16)

11-34

11-35

Animals as Habitats

• Skin

• Mucous membranes

• Obligate intracellular parasites

11-36

Skin

• Ex. Staphylococcus aureus. Gram-positive cocci,

catalase positive, causes wound infections,

food poisoning

• Ex. Staphylococcus epidermidis (normal flora)

Can cause disease in individuals with

other medical problems

11-37Staphylococcal toxic shock in the U.S. (25.6)

11-38

Mucous Membrane• Ex. Bacteroides. Anaerobic, Gram-negative rods and coccobacilli, 30%

of bacteria in feces

• Ex. Bifidobacterium. Anaerobic, Gram-positive rods, common intestinal flora in breast fed infants, may provide protective function

• Ex. Campylobacter and Helicobacter. Gram-negative rods, microaerophiles, C. jejuni causes diarrhea in humans Helicobacter pylori causes stomach ulcers

• Ex. Haemophilus. Small, Gram-negative coccobacilli,love blood, H. influenzae causes ear infections,respiratory infections and meningitis in children

11-39

Otis media(24.8)

11-40

Streptococcus pneumoniae in spinal fluidfrom a meningococcal meningitis patient (27.4)

Meningitis is alsocaused by:

Haemophilus influenzae

Neisseria meningitidis

11-41

Mucous Membrane

• Ex. Neisseria. Gram-negative diplococci, grow on mucous membranes, N. gonorrhoeae causes gonorrhea, N. meningitidis causes menengitis

• Ex. Mycoplasma. No cell wall, small pleiomorphic cells,M. pneumoniae causes “walking pneumonia”

• Ex. Treponema and Borrelia. Spirochetes, T. pallidiumcauses syphillis, Borrelia species cause Lyme Disease,

relapsing fever

11-42

Mycoplasma pneumoniae growing on agar (11.27)

11-43

Obligate Intracellular Parasites

• Cannot reproduce outside a host cell

• Transferred by blood-sucking arthropods

eg Rickettsia rickettsii causes Rock Mountain

Spotted Fever

• Can form a sporelike structure (Ex. Coxiella) Q fever

• Person to person transmission (Ex. Chlamydia)

C. trachomatis causes eye infection,

gonorrhea-like STD

11-44

Coxiella (11.29)

11-45

Chlamydia (11.30)

1 = reticulate bodies, noninfectious2-4 = dense bodies, infectious upon cell lysis

11-46

11-47

11-48

11-49

Table 11.1

Table 11.1cont

Table 11.2

Table 11.3

Table 11.3cont