micro quiz 1

Streptococcus pneumoniae — Gram stain

Gram-positive cocci in pairs (diplococci)

Other Streptococcus species — Gram stain

Gram-positive cocci in chains

Staphylococcus aureus — Gram stain

Gram-positive cocci in clusters; coagulase-positive

Staphylococcus epidermidis — Gram stain

Gram-positive cocci in clusters; coagulase-negative

• think the dangerous ones, mostly staph auerus

Corynebacterium diphtheriae — Gram stain

• resp infect with “bull neck”, can become systemic

Gram-positive, club-shaped rod

Listeria monocytogenes — Gram stain

• contaminated food— cold survival

• amp or tmp/smx treatment

Gram-positive, V- or L-shaped rod

Bacillus anthracis — Gram stain

Gram-positive rod

Bacillus cereus — Gram stain

• emetic or diarrheal forms; from foodborne illness

• spore formin

Gram-positive rod

Clostridium species — Gram stain

• botulinum

• tetani

• perfringens

• dificile

Anaerobic, gram-positive rods

Clostridioides difficile — Gram stain

Anaerobic, gram-positive rod

Streptococcus pyogenes — Drug of choice

• gram positive cocci

• beat hemolytic

Penicillin or clindamycin; use penicillin plus clindamycin for necrotizing fasciitis

Streptococcus agalactiae (Group B Streptococcus) — Drug of choice

• digestive/genital tracts

• sepsis, pneumonia, mengingitis in newborns

• gram positive cocci in chains and pairs

Penicillin

Viridans group streptococci — Drug of choice

• alpha hemolytic

Amoxicillin for prophylaxis; penicillin plus gentamicin for infection

• think to associate with dental carries

• mutans, salivarius, anginosus

Streptococcus pneumoniae — Drug of choice

Ceftriaxone; penicillin may be used, but resistance occurs

Staphylococcus species — Surgical prophylaxis

Cefazolin

MSSA — Drug of choice

Nafcillin, a penicillinase-resistant penicillin

Healthcare-associated MRSA (HA-MRSA) — Drug of choice

Vancomycin or linezolid

Community-associated MRSA (CA-MRSA) — Drug of choice

Trimethoprim–sulfamethoxazole (Bactrim) or doxycycline

Vancomycin-resistant Staphylococcus aureus (VRSA) — Drug of choice

Daptomycin or linezolid

Corynebacterium diphtheriae — Drug of choice

Diphtheria antitoxin plus penicillin

Listeria monocytogenes — Drug of choice

Ampicillin; trimethoprim–sulfamethoxazole (Bactrim) is an alternative

Bacillus anthracis — Drug of choice

• spore forming

• rod shaped , gram positive

Ciprofloxacin; a second CNS-active drug may be added in disseminated disease

Bacillus cereus — Treatment

• the “fried rice syndrome”— starchy foods at room temperature

No antibiotics unless the patient has a serious presentation

• quick onset, most cases self-resolving, you throw it up and out

Clostridium tetani — Treatment

Tetanus immune globulin plus metronidazole or penicillin G; also vaccinate

Clostridium botulinum — Treatment

Botulinum antitoxin

Clostridium perfringens — Drug of choice

• foodborne illness, gas gangrene

• gram +spore former

Penicillin G plus clindamycin

Clostridioides difficile — Drug of choice

Oral vancomycin or fidaxomicin

• second is a macrolide