ALT A patient delivers twins and experiences what appears to be severe pregnancy complications, possibly HELLP syndrome or something similar. After 5 days in the hospital, she spikes a fever and grows a gram-negative rod from blood cultures. What could this organism be and why can it be a serious concern for patients? A. Stenotrophomonas (may be multi-drug resistant). B. Elizabethkingia (may be hospital-acquired). C. Stenotrophomonas (may represent lab contamination). D. Carbapenem-resistant E. coli (may cause liver injury).

ALT A man in his mid 60s presents with fever, neck stiffness and headache. Symptoms started 10 days prior with an acute onset of headache after being on a boat for several hours. The patient reports being outdoors frequently on fishing trips. He lives in a flooded area with potential exposure to mice when his property floods. He has frequent exposure to mosquitoes, but no known tick bites or skin rashes. The CSF cell count showed elevated nucleated cells with mononuclear predominance. No organisms were seen on the CSF Gram stain, and no organisms grew in culture. The meningitis encephalitis PCR panel was negative. Lyme disease screening was negative and arboviral serologies were negative. The provider noted the patient had conjunctival suffusion and ordered an additional serology test, which revealed the diagnosis. What's the diagnosis? A. Leptospirosis. B. Anaplasmosis. C. Tularemia. D. Lymphocytic choriomeningitis.

ALT A man in his mid 60s presents with fever, neck stiffness and headache. Symptoms started 10 days prior with an acute onset of headache after being on a boat for several hours. The patient reports being outdoors frequently on fishing trips. He lives in a flooded area with potential exposure to mice when his property floods. He has frequent exposure to mosquitoes, but no known tick bites or skin rashes. The CSF cell count showed elevated nucleated cells with mononuclear predominance. No organisms were seen on the CSF Gram stain, and no organisms grew in culture. The meningitis encephalitis PCR panel was negative. Lyme disease screening was negative and arboviral serologies were negative. The provider noted the patient had conjunctival suffusion and ordered an additional serology test, which revealed the diagnosis. What's the diagnosis? A. Leptospirosis. B. Anaplasmosis. C. Tularemia. D. Lymphocytic choriomeningitis.

ALT A 29-year-old Nigerian male presented with high fever, vomiting, diarrhea, and altered mental status. He had previously been diagnosed with malaria 5 days prior and was receiving treatment with an unknown medication. A physical exam revealed tender hepatomegaly and conjunctival icterus. Initial laboratory studies showed severe anemia and thrombocytopenia, with hemoglobinuria, bilirubinuria and proteinuria on urinalysis. Giemsa-stained thick and thin smears show ring-shaped intracellular organisms. Due to a shortage of coartem, quinine was administered. Shortly after, the patient’s urine turned dark brown. What's the diagnosis? A. Acute post-streptococcal glomerulonephritis. B. Malarial hemoglobinuria. C. HIV-associated autoimmune hemolytic anemia. D. Flavivirus hemorrhagic fever.

ALT A 29-year-old Nigerian male presented with high fever, vomiting, diarrhea, and altered mental status. He had previously been diagnosed with malaria 5 days prior and was receiving treatment with an unknown medication. A physical exam revealed tender hepatomegaly and conjunctival icterus. Initial laboratory studies showed severe anemia and thrombocytopenia, with hemoglobinuria, bilirubinuria and proteinuria on urinalysis. Giemsa-stained thick and thin smears show ring-shaped intracellular organisms. Due to a shortage of coartem, quinine was administered. Shortly after, the patient’s urine turned dark brown. What's the diagnosis? A. Acute post-streptococcal glomerulonephritis. B. Malarial hemoglobinuria. C. HIV-associated autoimmune hemolytic anemia. D. Flavivirus hemorrhagic fever.

ALT A 67-year-old male with chest pain, headache and double vision with a history of latent syphilis presents with multiple rim-enhancing brain lesions on MRI. A Gram stain of a brain biopsy shows beaded Gram-positive rods and a Kinyoun stain shows acid-fast bacilli in the brain. What is the diagnosis? A. Treponema pallidum. B. Mycobacterium tuberculosis. C. Nocardia spp. D. Neisseria meningitidis.

ALT A 67-year-old male with chest pain, headache and double vision with a history of latent syphilis presents with multiple rim-enhancing brain lesions on MRI. A Gram stain of a brain biopsy shows beaded Gram-positive rods and a Kinyoun stain shows acid-fast bacilli in the brain. What is the diagnosis? A. Treponema pallidum. B. Mycobacterium tuberculosis. C. Nocardia spp. D. Neisseria meningitidis.

ALT In August 2024, an approximately 16-week-old kitten found as a stray was presented to a veterinary clinic in Minnesota for a swollen neck. Closer inspection of the neck revealed a furuncular lesion with a central pore, with a tan-colored organism seen moving inside of it. The pore was occluded with sterile lubricating jelly, encouraging the organism to come to the surface. The organism was able to be fully removed with gentle traction, and the wound was flushed with a dilute chlorhexidine gluconate solution. Can you guess the diagnosis? A. Hypoderma spp. B. Dermatobia hominis. C. Cuterebra spp. D. Cochliomyia hominivorax.

ALT In August 2024, an approximately 16-week-old kitten found as a stray was presented to a veterinary clinic in Minnesota for a swollen neck. Closer inspection of the neck revealed a furuncular lesion with a central pore, with a tan-colored organism seen moving inside of it. The pore was occluded with sterile lubricating jelly, encouraging the organism to come to the surface. The organism was able to be fully removed with gentle traction, and the wound was flushed with a dilute chlorhexidine gluconate solution. Can you guess the diagnosis? A. Hypoderma spp. B. Dermatobia hominis. C. Cuterebra spp. D. Cochliomyia hominivorax.

ALT A 52-year-old woman presents to the emergency department (ED) with severe lower leg pain a few days after a minor car accident. A fasciotomy is performed as surgeons are concerned about compartment syndrome, and within hours, one of the legs becomes completely necrotic, requiring amputation. The patient continues to decline and within 3 days of initial presentation, she passes away. The same organism is found growing in the blood culture collected in the ED and the tissue culture collected during amputation. What's the diagnosis? A. Aeromonas hydrophila. B. Pseudomonas aeruginosa. C. Vibrio vulnificus. D. Yersinia pestis.

ALT A 52-year-old woman presents to the emergency department (ED) with severe lower leg pain a few days after a minor car accident. A fasciotomy is performed as surgeons are concerned about compartment syndrome, and within hours, one of the legs becomes completely necrotic, requiring amputation. The patient continues to decline and within 3 days of initial presentation, she passes away. The same organism is found growing in the blood culture collected in the ED and the tissue culture collected during amputation. What's the diagnosis? A. Aeromonas hydrophila. B. Pseudomonas aeruginosa. C. Vibrio vulnificus. D. Yersinia pestis.

ALT The answer to last weekend’s #CaseStudySaturday question is 🦠… A. Fasciolopsiasis! Get the details and learn more when you watch the video on the #ASMClinMicro Case Study page: https://asm.org/Case-Studies/Swelling-Surprise-Mystery-Parasite-Unmasked-in-End

ALT New month, new #CaseStudySaturday! A 27 y.o. from India presented with a puffy face, ankles and loss of appetite. The patient was pale and experiencing bilateral pedal edema extending to the knees. Find out the diagnosis on Tuesday 🔗 https://asm.org/Case-Studies/Swelling-Surprise-Mystery-Parasite-Unmasked-in-End #ASMClinMicro

ALT A female patient presented to a dermatology clinic due to a worsening right cheek lesion from an insect bite that occurred while on a visit to the SW Pacific region of the US. The lesion started out as an erythematous papule and progressed to an ulcer, which continued to worsen despite topical antibiotic treatment. The lesion appeared well-circumscribed, crateriform, with sharply raised borders, as well as hemorrhage and granulation tissue on the ulcer bed. A biopsy from the edge of the lesion was performed. Can you guess the diagnosis?

ALT A 62-year-old woman presented to the Mayo Clinic with intermittent high-grade fevers and malaise. She had returned from a wildlife safari in Kenya and Tanzania 4 weeks earlier and recalled a painful insect bite on her left foot that had since resolved. She had been empirically treated with quinine and multiple antibiotics (levofloxacin, azithromycin, metronidazole, doxycycline and vancomycin) without improvement. Peripheral smears were reviewed – extracellular organisms with an undulating membrane and posterior kinetoplast were observed. Cerebrospinal fluid showed an elevated white blood cell count (164 cells/μL) and elevated protein (191 mg/dL). What's the diagnosis? A. Plasmodium falciparum (severe malaria). B. Trypanosoma brucei (human African trypanosomiasis). C. Trypanosoma cruzi (acute Chagas disease). D. Borrelia recurrentis (Louse-borne relapsing fever).

ALT A 62-year-old woman presented to the Mayo Clinic with intermittent high-grade fevers and malaise. She had returned from a wildlife safari in Kenya and Tanzania 4 weeks earlier and recalled a painful insect bite on her left foot that had since resolved. She had been empirically treated with quinine and multiple antibiotics (levofloxacin, azithromycin, metronidazole, doxycycline and vancomycin) without improvement. Peripheral smears were reviewed – extracellular organisms with an undulating membrane and posterior kinetoplast were observed. Cerebrospinal fluid showed an elevated white blood cell count (164 cells/μL) and elevated protein (191 mg/dL). What's the diagnosis? A. Plasmodium falciparum (severe malaria). B. Trypanosoma brucei (human African trypanosomiasis). C. Trypanosoma cruzi (acute Chagas disease). D. Borrelia recurrentis (Louse-borne relapsing fever).

ALT A 41-year-old patient was hit in the eye with a plastic net, causing an eye abrasion. He presented to urgent care with a burning sensation in the eye, photophobia, blurred vision and watering in the eye. Following his visit, the abrasion developed into a corneal ulcer. The ulcer did not heal within 3 weeks. A corneal ring infiltrate and cysts are seen in his eye during an eye exam. Cultures were ordered for bacteria and fungi and PCRs were ordered for bacteria, fungi, HSV, VZV and Acanthamoeba. What’s the diagnosis? A. Herpes simplex virus. B. Acanthamoeba. C. Staphylococcus aureus. D. Fusarium solani.

ALT A 41-year-old patient was hit in the eye with a plastic net, causing an eye abrasion. He presented to urgent care with a burning sensation in the eye, photophobia, blurred vision and watering in the eye. Following his visit, the abrasion developed into a corneal ulcer. The ulcer did not heal within 3 weeks. A corneal ring infiltrate and cysts are seen in his eye during an eye exam. Cultures were ordered for bacteria and fungi and PCRs were ordered for bacteria, fungi, HSV, VZV and Acanthamoeba. What’s the diagnosis? A. Herpes simplex virus. B. Acanthamoeba. C. Staphylococcus aureus. D. Fusarium solani.

ALT A patient admitted with community-acquired pneumonia was enrolled in the hospital’s sepsis pathway and treated with ceftriaxone and azithromycin. Despite stepwise escalation to piperacillin–tazobactam and later meropenem plus vancomycin, the patient deteriorated after only a brief partial improvement. The first blood culture was negative, the sputum was inconclusive and the urine culture was negative, creating major diagnostic uncertainty. A. Escherichia coli. B. Acinetobacter baumannii. C. Pseudomonas aeruginosa. D. Klebsiella pneumoniae.