WBR0251

Author	[[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Infectious Disease
Prompt	[[Prompt::A 25-year-old female presents to the physician’s office with complaints of fever, abdominal pain, and vaginal discharge. She is sexually active and has a history of the insertion of an intrauterine device. Physical examination reveals a temperature of 37.7 °C and suprapubic tenderness. A vaginal swab reveals a gram-positive rod with branching filaments. Which of the following organisms likely caused the patient's infection?]]
Answer A	AnswerA::''Neisseria gonorrhea''
Answer A Explanation	[[AnswerAExp::Neisseria gonorrhea is a gram-negative, kidney shaped diplococci.]]
Answer B	AnswerB::''Nocardia asteroides''
Answer B Explanation	[[AnswerBExp::Nocardia asteroides is an aerobic, partially acid fast, gram-positive rod with branching filaments, and it may result in multiple brain abscesses.]]
Answer C	AnswerC::''Actinomyces israelii''
Answer C Explanation	[[AnswerCExp::Actinomyces israelii, often forming sulfur granules, is a non-acid fast, anaerobic, gram-positive rod, forming long branching filaments resembling fungi. Actinomyces israelii is a normal flora of gingival crevices and the female genital tract. Actinomyces israelii infection often follows the use of intrauterine devices and likely results in symptoms similar to those observed in the patient.]]
Answer D	AnswerD::''Candida albicans''
Answer D Explanation	[[AnswerDExp::Candida albicans is a yeast with pseudohyphae and hyphae, which form germ tubes at 37 °C in serum.]]
Answer E	AnswerE::''Streptococcus agalactiae''
Answer E Explanation	[[AnswerEExp::Streptococcus agalactiae is a gram-positive, group B streptococcus (GBS), beta hemolytic, bacitracin resistant, hydrolyzes hippurate, which tests CAMP test positive. It is the most common cause of neonatal septicemia and meningitis.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient described in this scenario has Actinomycosis caused by Actinomyces israelii. It is a non-acid, fast anaerobic, gram-positive rod, forming long branching filaments resembling fungi and it forms sulfur granules. Actinomyces israelii is a normal flora of gingival crevices and female genital tract. It causes an invasive growth in tissues with a compromised oxygen supply. Pelvic Actinomycosis often results from the use of intrauterine devices. Actinomyces israelii infections may also occur folowing dental trauma, poor oral hygiene (lumpy jaw), an abdominal surgery, bowel trauma, or in the thoracic region through aspiration with a contiguous spread. In the CNS, Actinomyces israelii may cause solitary brain abscesses. Educational Objective: Pelvic Actinomycosis, caused by Actinomyces israelii, may result following use of intrauterine devices. References: ]]
Approved	Approved::Yes
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