Antibiotics and Bacterial Infections

Questions and Answers

Which antibiotic is commonly used to treat bacterial conjunctivitis?

Azithromycin

Linezolid

Moxifloxacin (correct)

Cephalosporin

What is the primary bacterium that causes trachoma?

Chlamydia trachomatis (correct)

Escherichia coli

Haemophilus influenzae

Streptococcus pneumoniae

Which of the following is NOT a common bacterial infection?

Pneumonia

Meningitis (correct)

Otitis media

Strep throat

What is the usual duration of bacterial conjunctivitis before it resolves on its own?

5-7 days Signup and view all the answers

Which antibiotic is used to treat H.pylori infection?

Macrolide Signup and view all the answers

What is the primary presentation of trachoma?

Roughening of inner surface of eye Signup and view all the answers

Which of the following is NOT a treatment for trachoma?

Moxifloxacin ophthalmic solution Signup and view all the answers

What is the primary cause of otitis media?

Viral URI Signup and view all the answers

What is the common pathogen causing otitis externa?

S. pneumoniae Signup and view all the answers

What is the first line of treatment for strep throat in a patient allergic to penicillin?

1G cephalosporin Signup and view all the answers

What is the treatment of choice for peritonsillar abscess?

Surgical I&D + Clindamycin Signup and view all the answers

What is the etiology of catarrhalis?

Virus Signup and view all the answers

What is the common symptom of otitis externa?

All of the above Signup and view all the answers

What is the treatment of choice for impetigo?

Oral antibiotics Signup and view all the answers

What is the complication of tonsillitis?

Peritonsillar abscess Signup and view all the answers

What is the antibiotic of choice for otitis media in a patient allergic to penicillin and cephalosporins?

Azithromycin Signup and view all the answers

What is the primary bacterium responsible for causing Rocky Mountain Spotted fever?

Rickettsia rickettsii Signup and view all the answers

What is the treatment of choice for Lyme disease in non-pregnant individuals?

Doxycycline Signup and view all the answers

What is the mode of transmission of Cellulitis?

Through cuts, scratches, burns, incisions, catheters, etc. Signup and view all the answers

What is the treatment of choice for MRSA infections?

Vancomycin Signup and view all the answers

What is the etiology of Pyogenes?

Streptococcus pyogenes Signup and view all the answers

What is the primary site of infection for Rocky Mountain Spotted fever?

Skin Signup and view all the answers

What is the treatment of choice for animal bites?

Amoxicillin/clavulanate Signup and view all the answers

What is the etiology of CAP pneumonia?

Multiple bacteria including S.pneumo, H.influenzae, S.aureus, and others Signup and view all the answers

What is the primary treatment for gonorrhea?

Single dose of ceftriaxone IM + azithromycin single dose PO Signup and view all the answers

What is the presentation of syphilis in the secondary stage?

Skin/mucous membrane rash Signup and view all the answers

What is the most common cause of UTIs?

E. coli Signup and view all the answers

What is the treatment for chlamydia?

Azithromycin single dose PO Signup and view all the answers

What is the term for asymptomatic bacteriuria?

Asymptomatic bacteriuria Signup and view all the answers

What is the treatment for syphilis in penicillin-allergic patients?

Tetracycline PO x 2 weeks Signup and view all the answers

What is a characteristic symptom of prostatitis?

Prostatic/perineal pain Signup and view all the answers

What is the term for UTIs that occur in non-pregnant outpatient women without abnormalities or instrumentation?

Uncomplicated UTI Signup and view all the answers

What is the treatment for a previously healthy individual with community-acquired pneumonia who has not taken antibiotics in the past three months?

Clarithromycin or azithromycin or doxycycline Signup and view all the answers

What is the primary cause of urethritis?

N. gonorrhea or C. trachomatis Signup and view all the answers

What is the treatment for severe C. difficile infection?

Vancomycin Signup and view all the answers

What is the typical presentation of diverticulitis?

LLQ pain and tenderness, fever, elevated WBC count Signup and view all the answers

What is the primary cause of community-acquired pneumonia?

Enterobacteriaceae, P. aeruginosa, Bacteroides spp., and enterococci Signup and view all the answers

What is the treatment for H. pylori infection?

Quadruple therapy Signup and view all the answers

What is the risk factor for developing C. difficile infection?

Previous use of antibiotics Signup and view all the answers

What is the bacterium that colonizes 100% of people with duodenal ulcers and 80% of gastric ulcers?

H. pylori Signup and view all the answers

Study Notes

Antibiotics

Cell wall inhibitors: PNCs, cephalosporins, carbapenems
Protein synthesis inhibitors: AGs, tetracyclines, macrolides, linezolid, mupirocin
Antifolate drugs
Fluoroquinolones

Common Bacterial Infections

Bacterial Conjunctivitis

Inflammation of conjunctiva from infection
Self-limited, resolves in 5-7 days
Presentation: conjunctival erythema, eyelid edema, mucopurulent discharge, crusting
Treatments: Tobramycin ophthalmic solution, Neomycin/Polymixin/Gramicidin ophthalmic solution, Moxifloxacin ophthalmic solution

Trachoma

Highly contagious ocular infection caused by Chlamydia trachomatis
Presentation: roughening of inner surface of eye, corneal breakdown, eye discharge, light sensitivity
Treatments: Azithromycin single dose, Sulfacetamide ophthalmic solution, Tetracycline ophthalmic solution/ointment

Otitis Media

Typically follows viral URI which can directly cause viral OM or predispose to bacterial OM
Etiology: S.pneumo (35%), H.influenzae, M.catarrhalis, viruses
Presentation: Immobile, erythematous TM; otalgia, otorrhea, fever
Treatment: mild-to-moderate resolves within 1 week without tx; NSAIDs, Amoxicillin, Cefdinir, Azithromycin

Otitis Externa

Results from combo of heat and retained moisture with desquamation and maceration of epithelium of canal
Etiology: P.aeruginosa, S.pneumo
Presentation: Ear discharge, pain with palpation of tragus/pinna, ear canal edema and discomfort
Treatment: Topical otic abx ± topical steroids, Neomycin/Polymyxin/Hydrocortisone otic suspension, Ciprofloxacin/Dexamethasone otic suspension

Streptococcal Pharyngitis

Pharyngeal infection caused by GAS aka S.pyogenes
Presentation: Sore throat, fever, chills, purulent tonsillar exudate, cervical LAD
Treatments: Penicillin V, 1G cephalosporin (Cephalexin) if PCN allergic, Clindamycin if allergic to PCN + cephalosporins due to resistance to macrolides

Peritonsillar Abscess

Also called quinsy, complication of tonsillitis
Consists of collection of pus in peritonsillar space; considered an ENT emergency
Etiology: Oral flora including anaerobes, GAS
Presentation: Severe U/L sore throat, dysphagia, dysphonia, referred otalgia, “hot potato voice”, LAD, trismus
Treatment: Surgical I&D + abx, Clindamycin or Metronidazole + Benzathine Penicillin G

Impetigo

Superficial skin infection seen in young children
Etiology: S.aureus, S.pyogenes
Presentation: Red papular lesions that evolve to pustules, honeycomb-like crusting affecting facial areas
Treatment: Mupirocin topical, Dicloxacillin or Cephalexin if extensive

Cellulitis

Bacterial infection of skin; bacteria enter through cuts, scratches, burns, incisions, catheters, etc.
Etiology: MRSA, MSSA, P.multocida (cat/dog bites), Eikenella cordoned (human bite), P.aeuginosa (penetrating injury)
Presentation: Localized pain, erythema, swelling, heat
Treatment: Depends on the cause, Amoxicillin/Clavulanate for animal bites, Dicloxacillin or Oxacillin for MSSA, Clindamycin, Vancomycin, or Linezolid for MRSA

Rocky Mountain Spotted Fever

Tick/mite-born illness
Transmitted by American dog tick (Dermacentor variabilis) and Rocky Mountain wood tick (D.andersoni)
Etiology: R.rickettsii
Presentation: Evolving macular rash; rarely CNS involvement, hypovolemia, HoTN, renal failure
Treatment: Doxycycline, Chloramphenicol if pregnant or allergic

Lyme Disease

Spirochetal infection transmitted by ticks (Ixodes scapularis)
Etiology: Borrelia burgdorferi
Presentation: ECM (stage 1), nonspecific sx like HA, muscoskeletal pain, neurologic deficits (stage 2), arthritis (stage 3)
Treatment: Doxycycline, Amoxicillin, Cefuroxime, or Erythromycin are alternative agents

Community-Acquired Pneumonia (CAP)

Infection of lung parenchyma
Etiology: S.pneumo, H.influenzae, S.aureus, K.pneumoniae, P.aeruginosa; atypicals like M.pneumoniae, C.pnuemoniae, Legionella spp.
Presentation: Fever, chills, cough, sweats, pleuritic CP, and dyspnea
Treatment: Clarithromycin, Azithromycin, or Doxycycline if previously healthy and no abx in past 3 mo, Respiratory fluoroquinolone (e.g., Moxifloxacin or Levofloxacin) if co-morbidities or previous abx use (alt: high-dose Amoxicillin/Clavulanate plus Macrolide)

Diverticulitis

Digestive disease in which pouches form within the bowel wall
Etiology: Enterobacteriaceae, P.aeruginosa, Bacteroides spp., and enterococci
Presentation: LLQ pain + tenderness, fever, elevated WBC count
Treatment: Ciprofloxacin plus Metronidazole, Alternative agents include TMP/SMX, Amoxicillin/Clavulanate

H.Pylori Infection

Colonizes 100% of people with DU, 80% of GU
Etiology: H.pylori
Presentation: Burning epigastric pain 90min to 3hr after eating (DU) or worse with eating/ unrelated (GU)
Treatment: Quadruple therapy first-line

C.Difficile Colitis

Diarrheal illness
Most commonly acquired in hospital
All abx has risk of CDI
Etiology: C.difficile
Presentation: Malodorous diarrhea, up to 20 BMs/day
Treatment: Metronidazole for mild-moderate disease, Vancomycin for severe disease

Urethritis

Commonly caused by N.gonorrhea or C.trachomatis
Presentation: Mucopurulent urethral discharge
Treat while symptoms are present
Treatment: Gonorrhea: single dose of Ceftriaxone IM + Azithromycin single dose PO, Cefpodoxime PO, or Cefixime PO, Chlamydia: Azithromycin single dose PO, Doxycycline PO x 7 days

Syphilis

Spirochetal infection caused by T.pallidum
Presentation: Painless chancre (1º), skin/mucous membrane rash (2º), symptomless (latent), neurologic/ cardiovascular sx (3º)
Treatment: Benzathine Penicillin G single dose, Tetracycline or Doxycycline x 2 weeks if allergic

Urinary Tract Infections (UTIs)

Term encompasses cystitis, pyelonephritis, prostatitis, and asymptomatic bacteriuria
Uncomplicated UTI refers to acute disease in non-pregnant outpatient women without abnormalities or instrumentation; complicated UTIs refers to all other UTIs
Etiology: E.coli (75-90%), S.saprophyticus, Klebsiella spp., Proteus spp., Citrobacter spp.
Presentation: Dysuria, freq/urgency (cystitis); fever, LBP, CVAT, N/V (pyelo); dysuria, freq, chills, prostatic/perineal pain (prostatitis)

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Description

This quiz covers types of antibiotics, including cell wall inhibitors and protein synthesis inhibitors, as well as common bacterial infections such as conjunctivitis, pneumonia, and cellulitis.