Essentials of Anatomy and Physiology

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Table 22–3 DISEASES CAUSED BY BACTERIA

Bacterial Species Discussion/Disease(s) Caused

Staphylococcus aureus

gram () coccus

Staphylococcus epidermidis

gram () coccus

Streptococcus pyogenes

(Group A streptococci)

gram () coccus

StreptococcusGroup B

gram () coccus

Streptococcus pneumoniae

gram () coccus

Enterococcus faecalis

and other species

gram () coccus

Neisseria gonorrhoeae

gram () coccus

Neisseria meningitidis

gram () coccus

Moraxella catarrhalis

gram () coccobacillus

Bacillus anthracis

gram () bacillus

(spore-forming)

Clostridium perfringens

and other species

gram () bacillus

(spore-forming)

Skin infections such as boils, pneumonia, toxic shock syndrome, osteomyelitis, sep-

ticemia. Most strains resistant to penicillin and many strains to related antibiotics as

well. An important cause of nosocomial infections, carried on the hands or in the

nasal cavities of healthcare personnel. Food poisoning characterized by rapid onset

(1–8 hours) and vomiting. No vaccine.

Normal skin flora; potential pathogen for those with artificial internal prostheses such as

heart valves and joints.

Strep throat, otitis media, scarlet fever, endocarditis, puerperal sepsis; possible immuno-

logic complications are rheumatic fever (transient arthritis and permanent damage to

heart valves) and glomerulonephritis (transient kidney damage, usually with com-

plete recovery). Rare strains cause necrotizing fasciitis, a potentially fatal hemolytic

gangrene. Several vaccines are in the testing stages.

An important cause of neonatal infection, the bacteria are acquired from the mother

during childbirth; risk factors are premature birth and intrapartum fever. May result

in pneumonia, meningitis, or septicemia. May be prevented by testing pregnant

women for Group B strep colonization and, if present, administering ampicillin. No

vaccine.

Pneumonia: accumulation of fluids and white blood cells in the alveoli. The vaccine con-

tains capsules of the most common strains; recommended for the elderly, and for

infants to prevent invasive disease. Possible cause of meningitis in adults with predis-

posing factors such as sickle-cell anemia, alcoholism, asplenism, or head trauma.

Normal colon flora. Has become an important cause of nosocomial infections of the uri-

nary tract. No vaccine. Other species (E.faecium) may be acquired from animals.

Some strains are resistant to many antibiotics.

Gonorrhea: inflammation of the mucous membranes of the reproductive and urinary

tracts. May cause scarring of reproductive ducts and subsequent sterility; in women

may cause pelvic inflammatory disease. Infants of infected women may acquire the

bacteria during birth; this is ophthalmia neonatorum and is prevented by antibiotic

eyedrops. No vaccine.

Meningitis: inflammation and edema of the meninges; pressure on the brain may cause

death or permanent brain damage. Also causes internal hemorrhages, DIC, and gan-

grene. Most common in older children and young adults, many of whom are asymp-

tomatic carriers. Most cases are sporadic, not part of epidemics. The vaccine is given

to military recruits and is strongly recommended for children ages 11–12, summer

campers, high school freshman, and college freshmen living in dorms; the vaccine

also prevents the carrier state. Post-exposure prophylaxis (prevention) involves antibi-

otics.

Otitis media and upper respiratory infection in children; pneumonia in adults, especially

the immunocompromised or elderly. No vaccine.

Anthrax: spores in soil may be acquired by cattle or sheep. People acquire disease from

these animals or from animal products such as wool or leather. The three forms are

pulmonary, cutaneous, and gastrointestinal, reflecting the portal of entry. The toxin

causes death of tissue, and the pulmonary form may be fatal. Rare in the U.S.,

because grazing animals are vaccinated. The vaccine for people was reserved for the

military, but has been offered to people thought to be exposed to spores. Anthrax is

a potential biological weapon.

Gas gangrene: normal soil flora may contaminate wounds; spores require anaerobic

environment (dead tissue); toxins destroy more tissue, permitting the bacteria to

spread; gas produced collects as bubbles in dead tissue. Food poisoning: from con-

taminated meat, self-limiting diarrhea. Some species have contaminated human tis-

sue (ligament, tendon) used for transplants. No vaccine.