WBR0251

Author	[[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1]]]
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 past history is significant for the insertion of an intrauterine device. Physical examination revealed a temperature of 99.8F and suprapubic tenderness. Culture of vaginal swab revealed a gram-positive rod with branching filaments. What is the likely causative organism of this 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 gram-positive rod with branching filaments, which should be distinguished from Actinomyces israelii that is a gram-positive rod with long branching filaments but anaerobic. Another difference between them is that Nocardia asteroides is partially acid fast and multiple brain abscesses unlike that of Actinomyces that is solitary.]]
Answer C	AnswerC::Actinomyces israelii
Answer C Explanation	[[AnswerCExp::Actinomyces israelii is a non-acid fast anaerobic gram-positive rod, forming long branching filaments resembling fungi. It forms sulfur granules. It is a normal flora of gingival crevices and female genital tract. It results as a complication of the use of intrauterine devices and could cause the symptoms in the patient above.]]
Answer D	AnswerD::Candida albicans
Answer D Explanation	AnswerDExp::Candida albicans are yeasts with pseudohyphae and hyphae that form germ tubes at 37 degree Celsius in serum.
Answer E	AnswerE::Streptococcus agalactiae
Answer E Explanation	AnswerEExp::Streptococcus agalactiae is a gram-positive cocci, a group B streptococcus (GBS), beta hemolytic, bacitracin resistant, hydrolyzes hippurate and CAMP test positive. It is the most common causative agent of neonatal septicemia and meningitis.
Right Answer	RightAnswer::C
Explanation	[[Explanation::The patient described in this vignette has Actinomycosis caused by Actinomyces israelii. It is a non-acid fast anaerobic gram-positive rod, forming long branching filaments resembling fungi. It forms sulfur granules. It 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 results as a complication of the use of intrauterine devices. Other ways of getting infected with Actinomyces israelii are either after a dental trauma or poor oral hygiene (lumpy jaw) or after an abdominal surgery or bowel trauma or it could occur in the thoracic region through aspiration with a contiguous spread. In the CNS, it causes solitary brain abscesses. Educational Objective Pelvic Actinomycosis results as a complication of the use of intrauterine devices and is caused by Actinomyces israelii. Educational Objective: References: ]]
Approved	Approved::Yes
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