XI - Other Bacteria Flashcards
Zoonoses
Brucella abortus, Francisella tularensis, Yersinia pestis, Pasteurella multocida
Small gram (-) rods without a capsule, contaminated dairy, direct contact, undulating fever
Brucellosis
Brucellosis: Cow
B. abortus
Brucellosis: Dog
B. canis
Brucellosis: Goat/Sheep
B. melitensis
Brucellosis: Sheep
B. ovis
Brucellosis: Treatment
Doxycycline + Rifampin
Small gram (-) rods, reservoir - rabbits, deer, rodents, transmission - ticks (Dermacentor), aerosols, contact, ingestion
Francisella tularensis (Tularemia)
Francisella tularensis: Treatment
Streptomycin, Gentamicin
Most virulent bacteria
Yersinia pestis
Small gram (-) rods with bipolar (safety pin) staining, reservoir - rodents, transmission - flea bite, inhalation
Yersinia pestis
Buboes, cutaneous hemorrhage
Yersinia pestis
Bubonic, Pneumonic and Septicemic Plague
Yersinia pestis
Yersinia pestis: Treatment
Streptomycin, Tetracycline
Short encapsulated gram (-) rod that exhibits bipolar staining, buttery colonies with musty odor due to indole production, osteomyelitis, reservoir - cats and dogs, transmission - animal bites
Pasteurella multocida
Pasteurella multocida: Treatment
Penicillin G
Aerobic, acid-fast rods, Ziehl-Neelsen (hot), Kinyoun (cold), high lipid content, mycolic acids, wax D, produces catalase and niacin, slow-growing on Löwenstein–Jensen medium (1 mo.), luciferase assay for drug resistance
Mycobacterium tuberculosis
Mycobacterium tuberculosis: Location
lungs
Mycobacterium tuberculosis: Transmission
respiratory droplets from coughing
TB Virulence Factors: Prevents phagosome-lysosomal fusion
Exported Repetitive Protein (Sulfatides)
TB Virulence Factors: Most important VF, prevents leukocyte migration
Cord Factor
TB Virulence Factors: Elicits delayed hypersensitivity
Tuberculin Surface Protein (Purified Protein Derivative - PPD)
Mycobacterium tuberculosis: Lesions
exudative, granulomatous
Central area of Langhan’s giant cells surrounded by a zone of epithelioid cells, tubercle is a granuloma surrounded by fibrous tissue that has undergone central caseation
Mycobacterium tuberculosis Granulomatous Lesions
TB Phase of Infection: Middle-lower lobes, subpleural granuloma, CLAD, radiologically detectable calcification
Primary Complex
TB: Subpleural Granuloma
Ghon’s Focus
TB: Subpleural Granuloma + Associated LN
Ghon’s Complex
TB: Radiologically Detectable Calcification
Ranke’s Complex
TB Phase of Infection: Apices (Simon’s Focus), cicatricial changes, subpleural blebs, cavitation, fibrosis, nodules, secondary colonization with A. fumigatus (fungus ball), pneumothorax
Reactivation TB
Reactivation TB: X-ray Findings
apices (Simon’s Focus), cicatricial changes, subpleural blebs, cavitation, fibrosis, nodules
PPD: HIV (+), AIDS, old TB, immunosuppressed
> 5 mm
PPD: High-risk Population
> 10 mm
PPD: Low-risk Population
> 15 mm
TB: Spectrum of Disease
pulmonary TB, miliary TB, scrofula (CLAD), erythema nodosum, TB meningitis, spondylitis (Pott’s), GI TB (ileocecal), renal TB, abdominopelvic TB
Cough ≥ 2 weeks ± local/constitutional symptoms
PTB Suspect
PTB: Local Symptoms
hemoptysis, chest pain, dyspnea
PTB: Constitutional Symptoms
night sweats, weight loss, anorexia, fever, chills, fatigue, malaise
Specimen: PTB
sputum AFB x 3
Specimen: TB Lymphadenitis
excisional biopsy
Specimen: TB Effusion
pleural fluid studies
Specimen: Genitourinary TB
urine AFB (PCR)
Specimen: Spinal TB (Pott’s)
tissue biopsy
Specimen: Abdominal TB
barium studies (intestinal), CT (extraintestinal), peritoneal fluid studies (AFB, Q/Q)
Specimen: TB Meningitis
CSF studies (AFB, Q/Q)
Specimen: TB Pericarditis
pericardial fluid studies (AFB, Q/Q)
PTB Treatment: New smear (+), new smear (-) with extensive disease, new severe extrapulmonary TB
Category I - Initiation: 2 HRZE, Continuation: 4 HR
PTB Treatment: Sputum smear (+), relapse, treatment failure, defaulter
Category II - Initiation: 2 HRZES + 1 HRZE, Continuation: 5 HRE
PTB Treatment: New smear (-) other than Cat. I, new less severe extrapulmonary TB
Category III - Initiation: 2 HRZE, Continuation: 4 HR
Mycobacterium tuberculosis: Prevention
droplet precautions, BCG vaccine limits extent of disease
Uses of BCG (Bacillus Calmette-Guerin) Vaccine
TB prevention, urinary bladder CA treatment (intravesicular infusion)
Cause pulmonary disease in immunocompromised hosts (CD4 < 50)
Mycobacterium Avium-Intracellulare Complex (MAI/MAC)
Mycobacterium Avium-Intracellulare: Treatment
Azithromycin
Aerobic acid-fast rods, can’t becultured in vitro (mouse footpad, armadillo)
Mycobacterium leprae (Hansen’s coccus spirilly)
Mycobacterium leprae: Location
humans, armadillos
Mycobacterium leprae: Transmission
prolonged exposure to nasal secretion of patients with the lepromatous form
Leprosy: One or few lesions
Tuberculoid
Leprosy: Little tissue destruction
Tuberculoid
Leprosy: Few acid-fast bacilli
Tuberculoid
Leprosy: Low transmission rate
Tuberculoid
Leprosy: Cell-mediated response to M. leprae
Tuberculoid
Leprosy: Lepromin skin test (+)
Tuberculoid
Leprosy: Many lesions
Lepromatous
Leprosy: Marked tissue destruction
Lepromatous
Leprosy: Many acid-fast bacilli
Lepromatous
Leprosy: High transmission rate
Lepromatous
Leprosy: Reduced/Absent cell-mediated response to M. leprae
Lepromatous
Leprosy: Lepromin skin test (-)
Lepromatous
Hypopigmented plaques, thickened superficial nerves, significant anesthesia
Tuberculoid
Leonine facies, erythema nodosum leprosum
Lepromatous
Tender red nodules, humps on both shins, signals acute lepromatous leprosy flare-ups
Erythema Nodosum Leprosum
Leprosy: Treatment for Tuberculoid Form
Dapsone, Rifampin
Leprosy: Treatment for Lepromatous Form
Dapsone, Rifampin, Clofazimine
Leprosy: Treatment for Erythema Nodosum Leprosum
Thalidomide → Phocomelia
Anaerobe, normal oral flora, local trauma (broken jaw, dental extraction), hard, non-tender swelling, sinus tracts draining sulfur granules
Actinomyces israelii
Actinomyces israelii: Treatment
Penicillin G, drainage
Actinomycete, aerobic, filamentous gram (+) rods with aerial hyphae, weakly acid-fast (Fite-Faraco stain), inhalation of particles from soil, mycetomas, lung and brain abscesses (orange colonies)
Nocardia asteroides
Nocardia asteroides: Treatment
TMP-SMX, drainage
Smallest free-living organisms
Mycoplasma pneumoniae
No cell wall, only bacteria with cholesterol in cell membrane, Eaton’s medium
Mycoplasma pneumoniae
Mycoplasma pneumoniae: Location
respiratory tract
Mycoplasma pneumoniae: Transmission
respiratory droplets
M. pneumoniae Virulence Factors: Attachment, inhibition of ciliary motion, necrosis
Toll-Like Receptor 2 Protein (P1 Adhesin)
M. pneumoniae Virulence Factors: Contributes to the damage to the respiratory tract cells
Hydrogen Peroxide
M. pneumoniae Virulence Factors: Autoantibodies against red cells and brain, lung and liver cells
Cold Agglutinins
Most common type of atypical pneumonia
Mycoplasma pneumoniae
“Walking Pneumonia” (clinical findings not compatible with x-ray), hemolysis, Stevens-Johnsons Syndrome, Raynaud’s, Guillain-Barré Syndrome
Mycoplasma pneumoniae
Most common infectious cause of Stevens-Johnsons Syndrome
Mycoplasma pneumoniae
Mycoplasma pneumoniae: Treatment
Macrolides (Erythromycin, Azithromycin)
Mycoplasma pneumoniae: Resistance
Penicillins and Cephalosporins - does not have a cell wall
Coiled spirochete, too thin for Gram-stain, cannot be cultured in vitro due to absence of TCA cycle, microaerophilic
Treponema pallidum
Treponema pallidum: Location
genital tract
Treponema pallidum: Transmission
sexual contact, transplacental
Syphilis: Within hours, enters lymphatics and multiplies, local non-tender ulcer (chancre) in 2-10 weeks
Primary Syphilis
Syphilis: Condyloma lata, maculopapular rash (palms, soles), fever, headache, malaise, anorexia, lymphadenopathy, after 1-3 months from inoculation
Secondary Syphilis
Syphilis: Many years after inoculation, granulomas (gummas), neurosyphilis (tabes dorsalis, dementia paralytica), aortitis
Tertiary Syphilis
Tabes dorsalis presents with _____ which _____ but does not react.
Argyll Robertson pupil, accomodates
Obliterative invasion of small blood vessels and vasa vasorum by Treponema pallidum causing endarteritis
Syphilitic Aortitis
Syphilis: Snuffles, saddle nose, mulberry molars, Hutchinson triad, saber shins, rhagades (angle of mouth), Higoumenakis sign, Clutton’s joints (synovitis), pulmonary hemorrhage
Congenital Syphilis
Syphilis: Hutchinson teeth, deafness, keratitis
Hutchinson Triad
Syphilis: Unilateral enlargement of the sternoclavicular portion of the clavicle → detachment
Higoumenakis sign
Most important diagnostic test for Primary Syphilis
dark-field microscopy
Secondary/Tertiary Syphilis: Diagnostic Tests
Screening - Rapid Plasma Reagin/Venereal Disease Research Laboratory (RPR/VDRL), Confirmatory - Fluorescent Treponemal Antibody-Absorption (FTA-ABS)
Causes for False (+) VDRL Results
Viruses (EBV, Hepatitis), Drugs (Marijuana), Rheumatic fever, Rheumatic arthritis, Lupus, Leprosy
Syphilis Diagnostic Test: Most specific, earliest positive, remains positive longest
Fluorescent Treponemal Antibody-Absorption (FTA-ABS)
Syphilis: Treatment
Benzathine Penicillin G
Influenza-like symptoms a few hours after receiving penicillin due to lysis of treponemes
Jarisch-Herxheimer Reaction
Syphilis: Prevention
condoms, post-exposure antibiotics, serologic follow-up
Weakly staining gram (-) spirochetes, largest medically important bacteria, aniline dye (Giemsa or Wright), BSK medium
Borrelia burgdorferi
Borrelia burgdorferi: Location
white-footed mouse, white-tailed deer
Borrelia burgdorferi: Transmission
bite from deer ticks (Ixodes scapularis)
Borrelia burgdorferi: Disease
Lyme Disease
Lyme Disease Stages: Erythema Chronicum Migrans (target lesion)
Stage 1
Lyme Disease Stages: Myocarditis (AV block), meningitis, Bell’s palsy
Stage 2
Lyme Disease Stages: Autoimmune migratory polyarthritis (onion skin lesions), acrodermatitis chronica atrophicans (skin atrophy - hands)
Stage 3
Borrelia burgdorferi: Treatment for Early Localized or Disseminated Disease
Doxycycline, Amoxicillin, Cefuroxime
Borrelia burgdorferi: Treatment for Late Disease
IV Penicillin, IV Ceftriaxone
Borrelia burgdorferi: Prevention
insecticides, insect repellants on clothing, protective clothing that reduces exposure of skin to insects
Relapsing fever from rapid antigenic changes due to programmed rearrangements of surface protein DNA
Borrelia recurrentis
Borrelia recurrentis: Transmission
human body louse (Pediculus humanus)
Borrelia recurrentis: Diagnostic Test
microscopy
Borrelia recurrentis: Treatment
Tetracycline, Erythromycin
Thin, coiled spirochetes, hook at one or both ends (Shepherd’s crook), obligate aerobe (only aerobic spirochete), Ellinghausen-McCullough-Johnson-Harris (EMJH) or Fletcher’s medium
Leptospira interrogans
Leptospira interrogans: Location
wild and domestic animals
Leptospira interrogans: Transmission
animal urine (dogs, livestock, rats), wading in floodwaters
Leptospires penetrate intact mucous membranes or skin through small cuts or abrasions, multiply rapidly and damage endothelium of small blood vessels, early - blood & CSF, late - urine, immune complex-mediated meningitis and glomerulonehritis
Leptospira interrogans
Leptospira interrogans: Diagnostic Tests
EMJH/Fletcher’s medium (+) after 2 weeks, Leptospire Microscopic Agglutination Test (Lepto-MAT) - gold standard
Leptospira interrogans: Incubation Period
2-20 days
Leptospirosis Phases: Fever, chills, intense headache, calf tenderness, conjunctival suffusion
Acute Leptospirosis
Leptospirosis: Cause of Calf Tenderness
rapid multiplication of leptospires in muscles with high oxygen
Leptospirosis: Cause of Conjunctival Suffusion
damaged and leaky conjunctival vessels, painful and itchy but with minimal tearing
Leptospirosis Phases: Aseptic meningitis, pulmonary involvement, hepatic necrosis, glomerulonephritis
Immune Leptospirosis
CSF pleocytosis ± meningeal symptoms, coincides with appearance of leptospire antibody titers
Aseptic Meningitis (Leptospira interrogans)
Snow-flake lesion on CXR
Leptospira interrogans
Leptospirosis: Cause of Glomerulonephritis
immune-complex deposition
Most severe form of leptospirosis
Weil Syndrome
Leptospirosis Phases: Jaundice, bleeding, uremia, orange cast skin (severe jaundice)
Weil Syndrome
Weil Syndrome: Triad
bleeding, uremia, orange cast skin (severe jaundice)
Weil Syndrome: Most common cause of death
respiratory failure from massive pulmonary hemorrhage
Leptospirosis: Treatment
Penicillin G
Leptospirosis: Prevention
Doxycycline chemoprophylaxis, vaccination of domestic livestock and pets, rat control
Obligate intracellular bacteria, energy parasites that use host ATP, cell wall lacks muramic acid, grows in cyclohexamide culture, cytoplasmic inclusion bodies (Giemsa)
Chlamydia trachomatis
Chlamydia trachomatis Forms: Inactive, extracellular, enters cells by endocytosis, infectious
Elementary Body
Chlamydia trachomatis Forms: Metabolically active, intracellular, seen microscropically, replicates via binary fission
Reticulate Body
Chlamydia trachomatis: Location
genital tract, eyes
Chlamydia trachomatis: Transmission
Sexual contact, passage through birth canal, hand-eye contact
Most common STD overall
Chlamydia trachomatis
Balance reached between host and parasite resulting in prolonged persistence of infection despite high antibody titers
Chlamydia trachomatis
C. trachomatis types A-C, chronic keratoconjunctivitis leading to scarring and blindness, Halberstädter-Prowazek inclusion bodies
Trachoma
Most common infectious cause of blindness
Chlamydia trachomatis
Round to oval cytoplasmic inclusion bodies near the nuclei of conjunctival epithelial cells in trachoma
Halberstädter-Prowazek inclusion bodies
C. trachomatis types D-K, NGU (Non-gonococcal Urethritis) in males, PID in females, co-infection with gonorrhea, neonatal conjunctivitis and pneumonia, Reiter’s Syndrome
Chlamydia GUT Infection
C. trachomatis types D-K, late-onset (2-4 weeks), striking tachypnea, paroxysmal cough (staccato cough), absence of fever, eiosinophilia
Chlamydia Neonatal Pneumonia
C. trachomatis types L1-L3, papule or vesicular which ulcerates and leads to suppurative inguinal lymphadenitis (buboes), (+) Frei test (intradermal injection of antigen)
Lymphogranuloma Venereum
Atypical pneumonia similar to Mycoplasma pneumoniae, associated with atherosclerosis
Chlamydia pneumoniae
Bird exposure (bird fancier’s disease - parrots, parakeets, macaws, cockatiels), sudden onset pneumonia, malaise fever, anorexia, sore throat, photophobia, severe headache
Chlamydia psittaci
Chlamydia: Treatment for STD
Azithromycin
Chlamydia: Treatment for Conjunctivitis
Erythromycin
Chlamydia: Treatment for Lymphogranuloma Venereum
Doxycycline
Chlamydia: Treatment for Psittacosis
Azithromycin
Cell wall resembles that of gram (-) rods, stain poorly with Gram-stain, obligate intracellular parasites (unable to produce sufficient energy to replicate extrecellularly), grown in cell culture, embryonated eggs, experimental animals, divide by binary fission within host cell
Rickettsiae
Detected using Weil Felix reaction (cross-reaction with antigens of OX strains of Proteus vulgaris)
Rickettsiae
Rickettsiae: Treatment
Doxycycline
Rocky Mountain Spotted Fever: Rash starts in _____ and spreads _____
wrist, centripetally
Rickettsia Typhus: Rash starts in _____ and spreads _____
trunk, centrifugally
Rickettsia: Q fever is Queer because
no rash, no vector, (-) Weil-Felix reaction, not obligate intracellular, does not have Rickettsia in genus name (Coxiella burnetti)
Diseases with Palm and Sole Rash
Coxsackievirus Type A (hand, foot & mouth disease), Rocky Mountain Spotted Fever, Syphilis
Cat-scratch disease, gram (-) rod, normal oral flora of cats, cat bite/scratch, cat-scratch fever (immunocompetent), bacillary angiomatosis (immunocompromised)
Bartonella henselae
Dogs, morulae in cytoplasm of monocytes, dog tick (Dermacentor) bite
Ehrlichia chaffeensis
Facultative gram-variable rod, clue cells (squamous cells attahced to bacteria, (+) whiff test (fishy odor with KOH), malodorous vaginal discharge (white, milk-splattered)
Gardnerella vaginallis
Small gram (-) rod, culture on chocolate agar with heme (factor X), painful genital ulcer (chancroid)
Haemophilus ducreyi
Mesenteric adenitis (pseudoappendicitis), gram (-) rods, domestic animals, oro-fecal transmission
Yersinia enterolitica
Granuloma inguinale (Donovanosis), encapsulated, pleomorphic, gram (-) bacillus, bipolar densities (Donovan bodies) that look like closed safety pins, small painless papule ulcerates to form beefy red ulcer with velvety surface, pseudobuboe formation
Klebsiella granulomatis
Klebsiella granulomatis: Treatment
Azithromycin
