Miscellaneous Pathogenic Organisms

Gardnerella vaginalis clinical manifestation

Vaginosis, polymicrobic disease associated with stinky discharge

Gardnerella vaginalis diagnosis

GPB (variable), clue cells (epithelial cells covered with bacilli), non-hemolytic on BAP but beta-hemolytic on V agar, catalase negative

What does G. vaginalis inhibit?

Alpha strep

What are the miscellaneous pathogens and their gram stains?

Gardnerella vaginalis (GPB, V), Streptobacillus moniliformis (long necklace GNR), Aggregatibacter sp. (small GNB/GNCB), Cardiobacterium hominis (GNB, rosettes), Capnocytophaga sp. (fusiform GNB), Chromobacterium violaceum (curved GNB), Calymmatobacterium granulomatis (pleomorphic GNB with bipolar staining), Spirillum minus (GNB with spirals), Bartonella bacilliformis (GNCB parasitizes RBCs)

Streptobacillus moniliformis pathology/clinical manifestation

NF in rodents/rat bite fever, Haverhill fever

Streptobacillus moniliformis diagnostics

SPS (S), cannot be recovered from blood culture bottle, grows like fluff in THIO, rarely used Rogosa medium

Aggregatibacter sp. pathology/clinical manifestation

NOF isolated from blood/endocarditis

Aggregatibacter aphrophilus morphology

Yellow with opaque zone in center

Aggregatibacter actinomycetemcomitans morphology

4- 6 pointed star @ 48 hrs

Cardiobacterium hominis pathology/clinical manifestation

NF respiratory and GI/Associated with endocarditis (cardio), patients with pre-existing conditions, and dental procedures

Cardiobacterium hominis diagnostics

Alpha-hemolytic pitting agar, no growth on MAC, oxidase positive, indole positive

Capnocytophaga sp. pathology/clinical manifestation

NOF/juvenile periodontitis and endocarditis (think phaga = eat)

Capnocytophaga sp. diagnostics

Microaerophilic/capnophilic, isolated from anaerobic culture, “gliding” motility

Chromobacterium violaceum pathology

Soil/water in tropical environments

Chromobacterium violaceum diagnostics

Violet pigment (viola-ceum) on BAP with almond smell, violet pellicle in broth, glucose fermenter, oxidase variable

Calymmatobacterium granulomatis clinical manifestation

Genital infection; specimens are lesion scrapings/puncture biopsies

Calymmatobacterium granulomatis diagnostics

Bipolar pleomorphic GNB, intracellular in histiocytes GNB “Donovan bodies”

Spirillum minus pathology

Rat bite fever; closely related to Campylobacter

Spirillum minus identification

Unable to culture; ID via microscope or animal inoculation

Barontella bacilliformis pathology/clinical manifestation

Endemic to mountains of South America, mosquito vector/etiologic agent for Carrion’s Disease (Oroya fever and Verruga peruana)

Bartonella henselae pathology/clinical manifestation

Cat scratch fever, transmitted by insects, lice, cat fleas; serology and molecular methods used to diagnose skin nodule/lesions and blood samples

What makes Bartonella sp. unique?

They parasitize RBCs