Chapter 20 - Gram Negative Bacilli

All species of Staphylococcus...

Lack spores

Enzyme that coagulates plasma

Coagulase

The toxin of Staphylococcus aureus strains that causes blisters and desquamation of skin in scalded skin syndrome

Exfoliative toxin

The bright red rash and fever of scarlet fever is due to...

Erythrogenic toxin

Scarlet fever is caused by strains of...

Streptococcus pyogenes

A common food intoxication is caused by enterotoxin-producing strains of...

Staphylococcus aureus

Which pathogen is the most common cause of neonatal pneumonia, sepsis, and meningitis in the United States?

Streptococcus agalactiae

Which organism is associated with commonly causing urinary tract infections in sexually active young adult and
adolescent females?

Staphylococcus saprophyticus

Which pathogen has drug resistant strains called MRSA?

Staphylococcus aureus

The most common site where carriers of Staphylococcus aureus carry this pathogen...

Anterior nares

Infections caused by Staphylococcus aureus include...

Folliculitis, furuncles and carbuncles, osteomyelitis, pneumonia

Staphylococcus food intoxication

Food becomes contemned by a human carrier; common associated foods include custards, ham, cream pastries, processed meats; symptoms come on quickly, and include nausea, vomiting, diarrhea

Staphylococcus epidermidis infections

From endogenous source; typically occur after insertion of shunts and prosthetic devices; catheterization can introduce the organism and lead to UTI; organism is coagulase negative

Symptoms of TSS

Fever, muscle pain, nausea, vomiting, diarrhea, sunburn-like rash, kidney and liver failure

Staphylococci can be differentiated from streptococci by the...

Catalase test

Rebecca Lancefield differentiated streptococci on the basis of differences in their...

Cell wall carbohydrates in a serological test

The M protein of Streptococcus pyogenes

Protects against phagocytosis and enhances adherence

Streptococcus pyogenes

Necrotizing fasclitis, erysipelas, impetigo, scarlet fever

Streptococcal pharyngitis

Purulent exude over the tonsils; leads to scarlet fever if it is an erythrogenic toxin-producing strain; can lead to serious sequelae; causes redness, difficulty in swelling, and fever

Scarlet fever

High fever, bright red rash on face, trunk, inner arms and legs, tongue; eventual desquamation of epidermis; septicemia

Necrotizing fasciitis

Associated with strains of Streptococcus pyogenes producing destructive enzymes and toxins.

The Group A streptococcal infection that has symptoms of fever, edema of skin near portal of entry, and an
elevated red, hot vesicular lesion

Erysipelas

Long-term sequelae of Group A streptococcal infections

Risk decreased with prompt treatment of skin infections and pharyngitis; development of rheumatic fever; appearance of sequelae with a few weeks after initial infection; development of acute glomerulonephritis

Enterococcus faecalis

Normal flora of the human large intestine; increasingly resistant to many antimicrobics; cause nosocomial wound infections, UTI, and septicemias; can cause endocarditis

Viridans streptococci

Not entirely groupble by Lancefield serology; most numerous residents of the oral cavity; opportunists that can cause subacute endocarditis; introduced to deeper body tissues by dental or surgical procedures

Streptococcus pneumoniae

Gram positive diplococcus with a capsule

Streptococcus pneumonia disease

Otitis media, meningitis, lobar pneumonia, bronchial pneumonia

People at greatest risk for pneumococcal infections

Adolescents and young adults

Neisseria gonorrhoeae

Cause of gonorrhea, opthalmia neonatorum, and are virulent due to fimbriae and a protease that inactivates IgA

Neisseria meningitidis

Capsule, pili, endotoxin, IgA protease, meningitis, reservoir is the nasopharynx of human carriers, and transmitted in close quarters

The instillation of antibiotics in newborn's eyes will prevent ophthalmia neonatorum in newborns. This disease
is caused by...

Neisseria gonorrhoeae

A positive Quellung reaction, or capsular swelling, is confirmatory for...

Streptococcus pneumoniae

Which chemical produced by S. aureus is also known as "spreading factor"?

Hyalurdoniase

Which chemical, produced by S. aureus, digests blood clots?

Staphylokinase

A patient has a suspicious skin infection and a culture is taken. Which media would be appropriate to select for staphylococci?

Mannitol salt agar

A pregnant woman is told she has a positive CAMP test and should be treated with a course of antibiotics and globulin. This test is indicative of...

Group B streptococci

Streptococcus pyogenes

Humans are the only significant reservoir; some of the streptococcal toxins act as super antigens; it can cause impetigo and erysipelas; infection is generally through direct contact

Staphylococcus aureus

Coagulase positive; carriers may be treated with antibiotics; most strains resistant to penicillin and ampicillin; causes furuncles, carbuncles, and abscesses

Sue brought her daughter Amy to the pediatrician complaining of a sore throat. The physician examines Amy
and observes that her throat is bright red and there are white pus-filled nodules on her tonsils. Which of the following conclusions should be made?

Rapid strep test performed before diagnosis made

It left untreated an infection with what bacteria can lead to pelvic inflammatory disease and infertility?

N. gonorrhoeae

Local Staphylococcus aureus infections often involve formation of an abscess.

True

Streptokinase causes the symptoms of scarlet fever.

False

It is theorized that rheumatic fever and acute glomerulonephritis could be the result of antibodies to Group A
streptococci that cross-react with patient tissues.

True

Most strains of Streptococcus pyogenes produce penicillinase.

False

Pneumovax is a vaccine for prevention of disease caused by strains of Neisseria meningitidis.

False

Impetigo involves itching papules that break and form a very contagious yellow crust.

True

Neisseria meningitidis and Neisseria gonorrhoeae are fastidious, gram-negative cocci that produce oxidase

True

An individual with asymptomatic N. gonorrhoeae may not spread the disease.

False

All staphylococci can be differentiated from all streptococci because only staphylococci produce the enzyme _____ that is easily detected in the lab.

Catalase

The two important hemolysins of Group A streptococci are _____ and _____.

Streptolysin O, streptolysin S

The viridans group of streptococci and the pneumococcus produce _____ hemolysis on blood agar.

Alpha

Staphylococcus, Streptococcus, and Neisseria tend to stimulate pus production and are collectively referred to
as _____ cocci.

pyogenic

The production of the enzyme _____ by Staphylococcus aureus is a key characteristic used to identify it from other species of Staphylococcus.

Coagulase

Streptococcus agalactiae is known as Group _____ streptococci.

B