Overview Snapshot A two-week-old neonate is brought to your office by his concerned mother who explains that her child is wheezing. Upon examination, you note an afebrile infant with a wheeze, stacatto cough, and increased anterior-posterior diameter of the chest. The lungs are tympanitic to percussion and the eyes appear crusty bilaterally. Introduction Classification obligate intracellular bacteria C. trachomatis Pathogenesis transmission sex birth (passage through birth canal) trachoma transmitted by hand-to-eye contact and flies reservoir genital tract eyes molecular biology obligate intracellular cannot make ATP requires live cells for growth in laboratory 2 forms reticulate body intracellular, metabolically active, replicating form "Reticulate Replicates" collections of reticulate bodies can be seen in the cytoplasm under light microscopy and are called "inclusion bodies" elementary body infectious, inactive, extracellular form small, dense "Elementary is Enfectious and Enters cell via Endocytosis" infection of mucosal surfaces leads to granulomatous response and damage multiple serotypes, each with a characteristic assocated disease cell wall does not contain peptidoglycan beta-lactam antibiotics are ineffective Diseases Chlamydia (sexually transmitted disease) the most common bacterial STD in the U.S. herpes and HPV are more common overall serotypes D-K initial presentation subacute (often undiagnosed) cervical motion tenderness ("chandelier sign") purulent cervical discharge sequelae nongonococcal urethritis reactive arthritis (Reiter's syndrome) cervicitis PID infertility conjunctivitis (adults and neonates) transmitted to neonates during birth most common cause of conjunctivitis in the 2nd week of life pneumonia in neonates (staccato cough) transmitted to neonates during birth ectopic pregnancy Lymphogranuloma venereum serotypes L1, L2, L3 ("L for lymphogranuloma") STD prevalent in Africa, Asia, and South America begins as small papule on genital mucosa rectal strictures painful lymphadenopathy can progress to genital elephantiasis diagnosis with serology (complement fixation, enzyme immunoassay, PCR). Positive Frei test (obsolete), granulomatous and neutrophilic inflammation do not confuse with granuloma inguinale (donovanosis) caused by Calymmatobacterium granulomatis papule becomes painless, exophytic mass Trachoma most common cause of preventable blindness associated with Africa serotypes A, B, Ba, C follicular conjunctivitis and in-turned eyelashes Laboratory Characteristics no muramic acid in cell wall therefore not seen on Gram stain Diagnosis cytoplasmic inclusions seen on Giemsa stain or fluorescent antibody-stain Treatment Azithromycin (one-time treatment) or doxycycline not sensitive to beta-lactams (cell wall does not contain peptidoglycan) treatment of N. gonorrhoeae with ceftriaxone monotherapy is often inadequate, as it does not cover for possible coinfection with Chlamydia Erythromycin prophylaxis in neonates erythromycin eyedrops given at birth protect against Chlamydia and N. gonorrhoeae topical and oral erythromycin used to treat neonatal chlamydial conjunctivitis oral erythromycin is used to prevent or treat systemic chlamydial infection
QUESTIONS 1 of 2 1 2 Previous Next (M1.MC.17) A sample is taken of an ulcer in the inguinal region of a 29-year-old Malaysian male who has had unprotected sex in the past few months. Intracytoplasmic inclusions are seen in the Giemsa staining in Image A. On which of the following can the organism in the staining be grown? Review Topic QID: 101476 FIGURES: A 1 Bordet-Gengou agar 8% (15/190) 2 Löwenstein-Jensen agar 12% (23/190) 3 Charcoal yeast extract agar with cysteine and iron 13% (25/190) 4 Eaton's agar 11% (20/190) 5 Yolk sac of a chick embryo 55% (104/190) Select Answer to see Preferred Response PREFERRED RESPONSE 5 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK