Microbiology Case Studies: Exam 1 – Flashcards
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A man is brought to the ED with a gun shot wound to the abdomen 20 min prior
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assume perforation of large bowel: mixture of anaerobic and aerobic, Gram+ and Gram- bacteria
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A patient in the ICU with severe pneumonia for one month has a bowel infarction and requires surgery
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assume perforation of large bowel, with likelihood that pt was colonized with bacteria resistant to one or more ABx (nosocomial infection)
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An alcoholic is found unconscious on the street. A day after admission to the hospital, the pt develops fever and pneumonia
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probable aspiration of oropharyngeal and gastric contents; stomach acid would cause tissue necrosis and damage and provide low-oxygen environment for the growth of anaerobes in lungs
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A junior high school student is brought to the ED with a red, painful swollen hand. Two days prior he had been in a fight at school, and his opponent had bitten him
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Mixed infection with oropharyngeal contents including anaerobes
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A 30 yo M presents with a 3-wk Hx of fever, night sweats, weight loss, and increasing dyspnea. He had been in good health and regularly exercised, but was once told that he had a "heart abnormality." On examination his temp is 38.4 degC, pulse 110, BP 130/50 with splenomegaly. White cell count 20,000. CV: oud systolic and diastolic murmurs
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propbable SBE with mouth viridans strep or enterococcus from the gut; most likely valve involvement is the aortic valve with regurgitation; Dx with blood cultures and echo
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A soccer player is brought to the ED unconscious after a severe collision with another player. On exam you notice a clear liquid coming out of the nose
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clear fluid indicative of CSF leak; nasopharynx flora is more like the skin flora than oropharyngeal or dental flora; few immune defenses enable even low virulence organisms like Proprionobacter acnes to grow
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The pt is receiving chemo for acute leukemia and now has a neutrophil count of 70. She has received ABx over the last wk for E. coli bacteremia. The CXR is unchanged from a wk ago but sputum culture now grows S. aureus. Another ABx is added for better coverage for S. aureus. Over the next 2 days her temp rises to 39 degC. Blood cultures are drawn, showing Gram+ organisms with budding
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ABx coverage for Gram+ and Gram- bacteria increases the likelihood that a fungal infection has occurred, possibly candida albicans
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ST is a 23 yo med student with sudden onset of fever, chills, malaise, headache, myalgia, sore throat, runny nose, sneezing. Roommate has same symptoms. Exam: erythematous, inflamed tonsils, no pharyngeal exudates. Throat culture: Group A strep. ST was seen in the ED in December.
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viral pharyngitis + group A strep normal respiratory flora
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PA is a 65 yo M in the ICU. Intubated and on the respirator with good oxygenation. No fever or purulent sputum. Exam: Lungs CTAB. CXR clear with not infiltrates or effusions. Sputum Gram stain reveals mixed flora with Gram+ cocci and thin, long Gram- bacilli. Sputum culture: normal respiratory flora, 2+ Pseunomonoas aeruginosa
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colonization with pseudomonas aeruginosa
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TM is a 38 yo F referred by the Public Health Dept. TM is a private cook in Manhattan and in the past 10 yrs, 7/8 families she worked for had outbreaks of illness presenting fever, malaise, headache, myalgia, maculopapular rash, bradycardia, constipation, bloody diarrhea. TM denies h/o similar illness
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Typhoid Mary Salmonella typhi carrier
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CT is a 18 yo F with PCR of cervical swab positive for Chlamydia trachomatis. CT denies dysuria, urinary frequency, urethral discharge
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asymptomatic Chlamydia trachomatis genital infection
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Pt presents with a puncture wound on the right foot from stepping on a nail x 1 wk. Pt now has difficulty swallowing and speaking and also suffers from generalized muscle stiffness and spasms, sweating, fever
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Infection with Clostridium tetani: release of 2-subunit A-B neurotoxin tetanospasmin, inhibiting release of inhibitory NT and enabling continuous stimulation by excitatory NTs --> tetanus
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52 yo F presents with meningoencephalitis after eating cheese made from unpasteurized milk. Pt has a Hx of pneumocystis pneumonia and recurrent varicella zoster is HIV negative.
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Dx: Listeria meningoencephalitis; targets the pregnant, neonates, elderly, and immunocompromised
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SA is a yo M in the ICU after abdominal surgery. Pt is on a ventilator and has a central venous catheter. Pt now has new fever, increased respiratory secretions, and oxygenation requirement. CXR: RLL infiltrate. Sputum Gram stain: WBCs with Gram+ cocci in clusters. Labs: elevated WBX count
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nosocomial MRSA pneumonia
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TS is a 25 yo F presents fever, hypotension, sunburn-like erythema over whole body, and altered mental status. Pt became ill 1 wk after cosmetic surgery. Upon convalescence, Pt experienced desquamination of hands and feet. Labs: increase in transaminases and increase in creatinine.
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toxic shock syndrome from TSS-1 released by Staphylococcus aureus
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GAS is a 10 yo M originally presented with abrupt onset of sore throat and fever. Exam reveals tonsillopharyngeal erythema and exudates. Pt did not see physician and recovered after 1 wk. 3 wks later GAS developed arthritis of the knees and ankles, spreading to elbows and wrists; also developing fever and erythematous macular rash. His pediatrician detected a heart murmur; labs showed elevated serum ASO.
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FACE (fever, adenopathy, lack of cough, exudates) + age; "sandpaper rash" indicative of strep pharyngitis (strep throat). 3 wk progression consistent with acute rheumatic fever (poststreptococcal, nonsupporative sequelae)
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20 yo M with presents with Hx of intermittent fever, fatigue, and 15-lb weight loss x 3 wks. 6 wks ago, Pt had dental surgery but did not take ABx prophylaxis. On exam his heart murmur (originally detected 10 yrs ago, post Strep throat Dx) is louder. Blood cultures grow Gram+ cocci that turn surrounding agar green
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viridans streptococcal endocarditis
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SP is a 65 yo M presenting with fever, dyspnea, cough, and purulent sputm x 4 days. Exam: decreased breath sounds and dullness over LLL. Sputum: WBC with lancelet-shaped Gram+ diplococci. Pt hasn't had any recent vaccines
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pneumococcal pneumonia caused by Streptococcus pneumoniae
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LM is a 30 yo Pt with lymphoma with initial presentation of fever, vomiting, and diarrhea x 4 days; followed by abrupt onset of headache, stiff neck, and severe drowsiness x 1 day. Pt's roommates have also had GI symptoms and ate cheese made from unpasteurized milk. LP: 800 WBCs (mostly polys), high protein
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meningitis from infection with Listeria monocytogenes; roommates are also affected but are immunocompetent
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The CBs are an elderly Asian couple who present with double vision, bilateral ptosis, dizziness, difficult swallowing, slurred speech. Wife has mild right upper extremity weakness. A bacterium and an associated toxin were detected in home-prepared fermented tofu
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foodborne botulism
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CD is a 52 yo F being treated in the hosptal with ceftazidime for nosocomial pneumonia. Pt now presents with diarrhea x 3 days with 5 watery stools/day, crampy abdominal pain, fever. Labs: elevated WBC count. Stool: fecal leukocytes
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ABx-associated C diff diarrhea
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BF is a 57 yo M with fever, RUQ abdominal pain and jaundice. Labs: elevated WBC and LFTs (liver function tests). Abd CT: multiple liver abscesses. CT-guided drainage: purulent material. Gram stain: WBCs and a mixture of Gram+ cocci and bacilli and Gram- bacilli
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polymicrobial liver abscess: culture grew E. coli, Klebsiella, Enterococcus faecalis, Bacteroides fragilis present though not identified
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FT is seen in the William Jefferson Clinton ER and Crisis Center in Little Rock, AK. 12 yo M with abrupt onset of a flu-like illness with fever, chills, and malaise that has lasted for wks. It is summer time. Pt has a non-healing ulcer on hand and painful lymph notes in axilla. Family keeps rabbits as pets and remembers finding a tick on boy several wks ago
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ulceroglandular tularemia
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YP was seen in a Tribal Health Clinic in NM. 23 yo M with abrupt onset of fever, chills, and weakness. Swollen and extremely painful and tender lymph nodes in left axilla
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bubonic plague
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BA is a 55 yo postal worker in Washington, DC. Fever, diaphoresis, cough productive of purulent sputum x 2 days. Dx by local physician with viral syndrom but 3 days later went to ED with worsening symptoms including dyspnea. CXR showed infiltrates and hilar fullness consistent with pneumonia. Died on day of admission
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inhalational anthrax
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TP is a 21 yo undergraduate with fever, malaise, and maculopapular rash arising first on the palms and soles of the feet. 3 wks ago Pt had a painless ulcer on his penis that resolved without any treatment
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secondary syphilis
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BB is from the northeast and has had a painless erythematous maculopapular rash that has been spreading x 1 wk. Pt remembers finding ticks on his body when camping 2 wks ago
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Lyme disease: erythema chronicum migrans
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BH presents Hx of fever, chills, headache x 2 wks. Pt had a similar episode 1 wk ago that resolved without treatment. Pt recently went camping in the Sierras and stayed in a log cabin that had a next of rats beneath it
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relapsing fever caused by Borrelia recurrentis or Borrelia hemsii
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CT is a 18 yo F college student with vaginal discharge x 5 days. Exam: erythematous cervix with mucopurulent discharge from os
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genital disease caused by Chlamydia trachomatis
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CP is a 65 yo M presenting Hx of fever, cough, no sputum x 3 days. Exam: chest: rhonchi and rales on left. CXR: LLL infiltrate
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Chlaymdia pneumonia: community acquired pneumonia
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RP isa 25 yo F refugee in Darfur, presenting with Hx of fever, rash, headache x 3 days. Rash started in axillary folds and upper trunk with outward spreading to rest of body, sparing the face, palms and soles. Exam: maculopapular rash
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epidemic typhus caused by Rickettsia prowazekii
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BZ is a 75 yo M with Hx of fever, rash, and headache x 1 wk. Rash started in axillary folds and upper trunk and spread outwards to reset of body, sparing face, palms, and soles. Pt states that this illness is similar to, but not as severe as an illness when he was in Poland just after the end of WWII. Exam: maculopapular rash.
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Brill-Zinsser disease caused by Rickettsia prowazekii
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RR is 55 yo M at the William Jefferson Clinton ER and Crisis Center in Little Rock, AK. Pt presents with Hx of fever and headache x 5 days and rash x 2 days. Rash started on wrists and ankles, then spread to arms and legs. Today the rash spread to the trunk. Exam: petechial rash without blanching
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Rocky Mountain Spotted Fever (Rickettsia rickettsii)
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CB is a 45 yo M seen in the Olympic Village Clinic in Sydney, Australia. Pt presented flu-like illness x 3 days with fever and cough, but no sputum. Pt had revisited a sheep farm in Queensland 2 wks prior to illness. Exam: Lungs CTAB. No rash
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Q fever caused by Coxiella burnetii
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AP is a 32 yo M seen in Lyme, CT. Pt presents with h/o fever, headache, myalgia. Pt had been hiking and later noticed a tick on his skin. Exam: no rash
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Ehrlichiosis caused by Anaplasma phagocytophilum
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BH is a 23 yo F who c/o of fever and swollen lymph nodes in right armpit. Pt has a new kitten. Exam: arms: scratch marks. Swollen tender axillary lymph nodes
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Cat-scratch disease (Bartonella henselae)
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NM is a 18 yo F who moved into the dorm 1 mo. ago. She presents fever, cough, sore throat, and rash x 1 day. Rash: small, raised, painful, reddish lesions (palpable purpura)
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MM is a 18 yo F from the same dorm as another 18 yo F presenting fever, cough, sore throat, rash x 1 day. MM has sudden onset of fever, headache, stiff neck x 1 day and says she is the sickest she has ever felt. Exam: petechiae on skin and soft palate. LP: 3000 WBCs and small Gram- diplococci
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NG is a 18 yo M from the same dorm as the 18 yo F with fever, cough, sore throat, rash x 1 day and 18 yo F with sudden onset of fever, headache, stiff neck x 1 day. NG presents with dysuria and purulent discharge x 2 days. Gram stain: WBCs and Gram- diplococci. His gf has a warm erythematous area on dorsum of foot and had several small pustules on both feet. She denies vaginal discharge or bleeding and just finished having her period
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19 yo F presents 2 wks foul smelling vaginal discharge. No fever or abdominal pain but reports vaginal bleeding after intercourse. Unprotected vaginal intercourse with 2 men over past 6 mo. Pt missed her last period. Pelvic exam positive for mucopurulent cervical discharge. No cervical motion tenderness. NAAT sent for GC/CT. Urine pregnancy test sent. Pending results, decision made to treat for GC/CT
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Tx for gonorrhea and chlamydia: cephtriaxone and azythromycin; don't give doxycyline because might be pregnant (chelates Ca)
