Clin med gram neg and pos

Recent clindamycin + profuse watery diarrhea

Clostridioides difficile

First-line treatment for C. difficile

Oral vancomycin (or fidaxomicin)

Most common antibiotic that causes C. difficile

Clindamycin

Most concerning complication of C. difficile

Toxic megacolon

Severe pain out of proportion + crepitus + hemorrhagic bullae

Clostridium perfringens (gas gangrene)

First-line management of gas gangrene

Immediate surgical debridement + IV penicillin + clindamycin

Do you wait for cultures before treating gas gangrene?

No—treat immediately

Infant <12 months + honey + constipation + hypotonia

Infant botulism

Botulinum toxin mechanism

Inhibits acetylcholine release

Botulism causes what type of paralysis?

Descending flaccid paralysis

Treatment for botulism

Botulinum antitoxin + respiratory monitoring

Major cause of death in botulism

Respiratory failure

Puncture wound + lockjaw + muscle spasms

Tetanus

Tetanus toxin mechanism

Inhibits GABA (disinhibition)

Tetanus causes what type of paralysis?

Spastic paralysis

Classic tetanus findings

Trismus, risus sardonicus, opisthotonus

Treatment for tetanus

Debridement + tetanus immune globulin + penicillin + metronidazole

Tdap booster after contaminated wound

If ≥5 years since last vaccine

Tdap booster after clean minor wound

If ≥10 years since last vaccine

Pregnant woman + unpasteurized cheese + flu-like illness

Listeria monocytogenes

Foods associated with Listeria

Unpasteurized dairy, deli meats, raw vegetables

Neonate complication of Listeria

Meningitis

Treatment for invasive Listeria

Ampicillin

Gray pseudomembrane + bull neck

Diphtheria

Pseudomembrane characteristic

Bleeds when scraped

Major fatal complication of diphtheria

Myocarditis

Treatment for diphtheria

Penicillin or erythromycin + diphtheria antitoxin

Diphtheria prevention

DTaP/Tdap vaccination

Painless black eschar

Bacillus anthracis (cutaneous anthrax)

Inhalational anthrax chest x-ray

Widened mediastinum

Anthrax microscopy

Boxcar-shaped gram-positive rods with Medusa head appearance

Treatment for anthrax

IV ciprofloxacin + clindamycin + antitoxin

Additional step in suspected anthrax

Notify state health department

Whooping cough + post-tussive emesis

Bordetella pertussis

Three classic pertussis findings

Paroxysmal cough, inspiratory whoop, post-tussive emesis

Treatment within 3 weeks of cough onset

Azithromycin

Treatment after >3 weeks of cough onset

Supportive care (unless high-risk)

Most contagious stage of pertussis

Catarrhal stage

Currant jelly sputum + bulging fissure

Klebsiella pneumoniae

Risk factors for Klebsiella

Alcohol use disorder, diabetes, COPD, CKD, hospitalization

Treatment for Klebsiella

Cefdinir or levofloxacin (guided by culture)

Hotel stay + pneumonia + diarrhea + failed beta-lactam

Legionella pneumophila

Legionella exposure

Contaminated water, cooling towers, hotels

Legionella diagnostic test if sputum unavailable

Urine antigen

Treatment for Legionella

Azithromycin or levofloxacin

Hot tub folliculitis or otitis externa

Pseudomonas aeruginosa

Green pigment + grape-like odor

Pseudomonas aeruginosa

Common Pseudomonas risk factors

Burns, CF, ventilators, catheters, puncture wounds

IV treatment for serious Pseudomonas infection

Piperacillin-tazobactam, cefepime, or aztreonam

Oral treatment for Pseudomonas

Ciprofloxacin or levofloxacin

Cat bite + cellulitis

Pasteurella multocida

Treatment for Pasteurella

Amoxicillin-clavulanate

Cat scratch + regional lymphadenopathy

Bartonella henselae

Treatment for cat scratch disease

Azithromycin

Petechial rash + meningitis

Neisseria meningitidis

First-line treatment for meningococcal meningitis

IV ceftriaxone

Prevention for meningococcal disease

Meningococcal vaccine

Child with otitis media, sinusitis, or COPD exacerbation

Haemophilus influenzae

Most virulent H. influenzae strain

Hib

Treatment for H. influenzae

Amoxicillin-clavulanate (or cefdinir, doxycycline, azithromycin, levofloxacin)

Prevention of invasive H. influenzae

Hib vaccine

Top 3 cause of otitis media in children

Moraxella catarrhalis

Treatment for Moraxella

Amoxicillin-clavulanate

Young adult with dry cough + normal exam + failed amoxicillin

Mycoplasma pneumoniae

Walking pneumonia organism

Mycoplasma pneumoniae

Treatment for Mycoplasma

Azithromycin, doxycycline, or levofloxacin

Most common cause of uncomplicated UTI

Escherichia coli

First-line treatment for uncomplicated E. coli UTI

Nitrofurantoin

Other first-line UTI options

TMP-SMX or fosfomycin

Traveler's diarrhea organism

Escherichia coli

Undercooked chicken or eggs + diarrhea

Salmonella

Salmonella treatment (uncomplicated gastroenteritis)

Supportive care only

Who should receive antibiotics for Salmonella?

Infants <3 months, immunocompromised, sepsis, typhoid fever, meningitis, osteomyelitis

Sickle cell patient with osteomyelitis organism

Salmonella

Complicated or nosocomial UTI + biofilm formation

Proteus mirabilis

Treatment for Proteus UTI

TMP-SMX or ciprofloxacin