Microbiology Flashcards
When to give tetanus immune globulin
If patient is unvaccinated, uncertain of vaccination, or <3 tetanus toxoid doses with a DIRTY wound
Patients with asplenia are at risk for
infection due to encapsulated bacteria due to deficiency in antibody-mediated phagocytosis
Newborn with microcephaly, ventriculomegaly, periventricular calcifications, hepatosplenomegaly, thrombocytopenia
Congential CMV (saliva)
Pt with HIV (CD4 <100) & febrile wasting, cough, SOB, night sweats, mucocutaneous ulcer, LAD, HSM, pancytopenia
disseminated Histoplasmosis
- dx with urine histoplasma antigen
- tx w/ amphotericin B
Pt with fever, muscle stiffness, trismus/lockjaw, and painful muscle spasms triggered by physical stimuli
tetanus
cephalocaudal spread of maculopapular rash with fever and arthralgias
Rubella (German measles)
19 year old with dry cough, sore throat, headache, maculopapular rash on extremities. Small pleural effusion and increased interstitial markings
Mycoplasma pneumonia
elderly man with severe unilateral ear pain. Ear canal is mildly erythematous with purulent drainage and granulation tissue
necrotizing otitis externa
- pseudomonas
- defecits in lower cranial nerves (vii, x, xi)
- tx: iv cipro with surgical drainage
Patient with acute febrile illness and AMS. Was recently bit by a tick. Leukopenia, thrombocytopenia, and elevated LFTs
Ehrliciosis (carried by lone star tick/reservoir is white tail deer)
-tx: doxycycline empirically
Pt on mission trip around pig farmers has a new seizure. CT show multiple cysts with surrounding edema
neurocysticercosis
- Taenia solium (pork tapeworm) eggs
- tx with albendazole, steroids, phenytoin
Pt with fever, hemoptysis, and chest pain with neutropenia. Ct scan pf chest shows multiple nodular lesions with surrounding ground-glass opacities
Invasive aspergillosis
- RF: immunocompromised
- tx: Voriconazole + capsofungin
Tx of food borne botulinum
horse-derived antitoxin
Young patient with viral URI (flu) develops worsening sx with fever of 104. Xray showed multilobar cavitary infiltrates and thin walled cavities
Staph aureus (MRSA)
HIV patient with linear ulcers with intranuclear and intracytoplasmic inclusions in distal esophagus. Was treated with oral oral fluconazole 2 weeks ago for odynophagia
CMV
tx: Ganciclovir
CD4 <50
Infection after starting chemotherapy
- organism
- treatment
Pseudomonas aeruginosa
Pip-tazo, meropenem, cefepime (covers gram + and -)
Pregnant patient that had a fever and diffuse maculopapular rash (non-pruritic) several weeks ago. U/S of infant shows enlarged ventricles and multiple intracranial calcifications. Hepatomegaly also noted.
Toxoplasma gondii
4 year old girl with “itchy private parts” mostly at night. Perianal area is excoriated and erythematous. No vaginal discharge but erythematous vulva.
Enterobius vermicularis (pinworms) - helminth tx: pyrantel pamoate or albendazole for pt and home contacts
Pt recently traveled to the Caribbean now returns with fever, malaise, polyarthralgias, throbocytopenia, pymhopenia
Chikungunya fever (from Aedes mosquito)
Pt presents with fever, double vision, painful swelling around his eyes, pain in neck and jaw muscles. Lab studies show increased eosinophils
Trichinellosis
- endemic in Mexico, China, Thailand
- ingestion of undercooked meat
- Intestinal phase (1 week): asx, abdominal pain, N/V, diarrhea
- muscle stage: myositis, fever, sugunal splinter hemorrhages, periorbital edema, esosinophilia (>20%)
Side effect of aminoglycosides
Ototoxicity by damaging cochlear cells
Gentamicin can also damage the motion-sensitive hair cells
complications of infectious mono
acute airway obstruction
autoimmune hemolytic anemia and thrombocytopenia
splenic rupture
infectious endocarditis causes:
hospital acquired
community acquired
post dental procedure
Staph (hospital)
Strep (community)
Viridans/sanguinis (post dental)
Severe watery diarrhea in an HIV patient with CD4 of 94 and a low grade fever. Started working at a horse breeding farm
Cryptosporidium parvum
- modified acid fast stain
Infant born with diffuse intracranial calcifications, ventriculomegaly, hepatomegaly, jaundice
Congenital toxoplasmosis
infant fails hearing screen. Mom traveled out of country while she was pregnant, got sick and had arthralgias. Pt has loud murmur heard over second ICS on left.
Rubella (German measles) - congenital
- sensorineural hearing loss
- cataracts
- PDA
Plantar hyperkeratotic papules that are painful to walk on. Pt is sexually active
HPV
Pt from Wisconsin develops fever, night sweats, weight loss. Pt has multiple skin lesions and CXR shows left upper lobe consolidation and two lytic lesions in the anterior ribs
Blastomycosis
Pt is traveling to India and wants to be protected from malaria
Mefloquine chemoprophylaxis until 4 weeks after return
- can use chloroquine in sensitive areas
- in non-sensitive areas, can give atovaquone-proguanil, doxycycline, mefloquine
Pneumonia, diarrhea, and hyponatremia
Legionella
- urine antigen test
- treat with macrolides or fluoroquinolones
Pt presents with fever, chills, dysphagia, and drooling. Has a fever, tongue is displaced posterior and superior due to swollen area on floor of mouth. B/l submandibular area is tender, indurated, nonfluctuant with palpable crepitus
Ludwig angina
- rapidly progressive cellulitis of submandibular space
- many cases arrive from dental infections
- tx: IV abx (ampicillin-sulbactam, clindamycin)
Diarrhea in HIV patients
<180: Cryptosporidium (watery diarrhea)
<100: mycrosporidium (fever rare)
<50: MAC (fever >102.2 & watery diarrhea)
CMV (frequent, small volume diarrhea, hematochezia)
Pt with HIV develops red/purple papules that enlarge into nodules. They are friable and bleed easily when palpated. He also has hepatosplenomegaly
Bartonella - bacilliary angiomatosis
- tx with doxy or erythromycin
Immunocompromised patient presents with bloody diarrhea, mild hepatitis, and pulmonary complaints
CMV
Pt has deep puncture wound by neighbor’s cat. Vaccinations are UTD. Most recent tetanus was 3 years ago
Pasturella - tx with Augmentin
Pt has single intrahepatic cyst that is well-defined with eggshell calcifications. She has had dogs at home for 10 years
Hydatid cyst due to Echinococcus granulosus
- causes unilocular cystic lesions that can occur in any organ
Pt returned from kenya 2 weeks ago now has fevers, headache, and malaise. He developed intense chills followed by fever and diaphoresis. He experienced similar sx a few days ago
Malaria - cyclical fevers
Pt develops submandibular mass after tooth extraction. Mass expresses fluid with yellow granules. Anaerobic culture grows filamentous gram positive rods with rudimentary branching.
Actinomyces
tx = penicillin
Tx of PCP
Bactrim and corticosteroids
Pt presents with fever, right cheek pain and bloody nasal discharge. Pt has a 30 year hx of DM type 2. CT scan shows opacification and bony erosion of the right maxillary sinus
Mucormycosis (Rhizopus)
Where does E corrodens come from
periodontal infection
Polyarthralgias, tenosynovitis, and painless vesiculopustular skin lesions
disseminated gonoccocal infection
Common cause of cellulitis in burn victims and patients with uncontrolled DM
Psuedomonas - gram neg rod
Pt was bit on the leg while skinning small game in Arkansas. There is a painful ulcer with regional LAD
Francisella tularensis
- tx with aminoglycosides
Progressive abdominal discomfort and nausea. Previous farmer in Guatemala. Hepatomegaly present with 10 cm , smooth, round cyst with daughter cysts inside.
Echinococcus granulosus
- dog tapeworm
- tx: albendazole
- hydatid cyst with internal septations
50 year old male develops abdominal pain, bloody stools, and malaise 4 months after kidney transplant. Blood smear shows atypical lymphocytes and colonoscopy shows multiple ulcerations throughout colon.
CMV colitis
Tx of H. ducrei
single PO dose of azithromycin
nasopharyngeal carcinoma is associated with reactivation of
EBV - usually in those from asia
- early spread to cervical LN is common
Patient with worsening pharyngitis develops thrombosis in IJ, sever neck swelling and tenderness. CXR shows multiple peripheral lung nodules, some with cavitation
Fusobacterium necrophorum
- Lemierre syndrome
southeast Asian man presents with a well-demarcated hypopigmented skin lesion on the left upper arm with no pinprick sensation. The ulnar nerve is thickened and tender to palpation at the elbow and he has numbness and tingling in his fingers.
Leprosy
- Mycobacterium leprae
- need full thickness biopsy
- tx: dapsone + rifampin
clostridium septicum
highly associated with colon cancer
- can cause gas gangrene and tissue necrosis
(as well as strep bovis)
most common cause of nosocomial blood infections
central venous catheters
- staph aureus
- candida
parvovirus in adults
acute, symmetric arthralgias (looks like RA)
pneumonia in a patient with prior lung dz. CT shows dilated airways (bronchiectasis)
pseudomonas
- b-lactam + fluoroquinolone
Pts with neutropenic fever should be immediately treated for
pseudomonas
- pip/tazo, ceftazidime, meropenem, imipenem, and cefepime
candida appearance on KOH
pseudohyphae and budding yeast
aminoglycosides
can cause sensorineural hearing loss and ATN
antibiotics most likely to cause c diff
ampicillin and clindamycin
14 year old with 2-week history of a non-productive cough, low-grade fever, sore throat, and occasional chest pain that worsens with deep inspiration.
Atypical pneumonia (walking) tx: macrolides
