Microbiology - Block 1 - Part 3

davidwurbel7's version from 2015-06-05 15:08


Question Answer
Enveloped ss(-)RNA. Form syncytia due to fusion (F) glycoprotein. Contain haemagglutinin (except RSV). Human-restricted respiratory transmitted by aerosol. Highly contagious. One serotype for Measles and Mumps (MMR). Ribavirin treatment available for RSV only if infant life is at riskParamyxo
Haemagglutinin positive test rules out which paramyxo virusRSV
Enveloped ss-RNA, Transmitted by aerosol. Coryza, cough, conjunctiva – 3C’s. High fever with symptoms. Koplik spots. Maculo-popular rash starting from forehead down to trunk. Complications include Viral pneumonia (giant cell), Bacterial pneumonia, Encephalitis, SSPE-Subacute Sclerosing Panencephalitis. Diagnosis by Giant multinucleated cells with cytoplasmic inclusions. Prevention by MMR (attenuated) vaccine and Passive IgGMeasles
Highly contagious ~90% & infects only humans. Person to person by respiratory dropletsMeasles
White salt like spot on the mucous mucosaKoplik's Spots
Koplik's spot is pathognomic forMeasles
Measles complication mainly seen in people with immunocompromised patients ie. AIDSGiant Cell Pneumonia
Complications include giant cell pneumonia, bacteria pneumonia, Post-infectious encephalitis, Sub-acute sclerosing panencephalitis (SSPE)Measles
50% deaths causes by a vaccine-preventable diseaseMeasles
MMR vaccine (live attenuated virus)Measles
Measles prevention for unvaccinated immunocompromised children after exposurePassive IgG Immunoglobulin
Enveloped ss-RNA. Transmitted by aerosol. Clinical Presentation - Swollen glands, “Bull neck" Complications - Orchitis, Pancreatitis, Meningo-encephalitis. Diagnosis - Giant multinucleated cells with cytoplasmic inclusions. Prevention by MMR (attenuated).Mumps
Acute benign viral parotitis (painful swelling of the salivary glands)Mumps
Complications include Orchitis – testicles (Pre-vaccine era – major cause of sterility) Pancreatitis & thyroiditisMumps
Enveloped ss-RNA that does not have HA. High risk for neonates. Seasonal (winter). Transmitted by aerosol. Clinical presentation as General URTI (older children) viral pneumonia (MC) and Bronchiolitis (MC neonates). Diagnosis - Forms syncytia; does not hemagglutination. RT-PCR is preferred. Treatment Ribavirin (only life-threatening)RSV
Enveloped ss-RNA. Many subtypes (PIV1-4). Seasonal (spring/fall). Associated with hospital outbreaks. Transmitted by aerosol. Clinical Presentation - Croup MCC (stridor, seal-like cough, Steeple sign), Common cold, Pneumonia, Bronchiolitis. Diagnosis by Syncytia and hemagglutination. Treatment is only supportive.PIV
Seal Bark Cough with strider and "steeple" sign on x-rayCroup


Question Answer
Arboviruses spread by mosquitoes found in forests and maintained in squirrel.La Cross Encephalitis Virus and California Encephalitis Virus
Fever, headache, lethargy, and vomiting. Seizures occur in 50% of patients with encephalitis, usually early in the illness. Signs of meningitis may also be present. Lasts 10-14 days. Less than 1% deathLa Cross Encephalitis Virus and California Encephalitis Virus
Human infection by close contact or inhalation of aerosolized rodent urineHanta
General flu-like symptoms, pulmonary edema, shock, respiratory failure, death within days - Mortality Rate: 30-60%Hanta
Mostly tropics of Africa and South America. From rodents to humans (exposure to urine)Arenavirus Family
Found in West Africa. High fever, flu-like symptoms, petechiae, & occasional visceral hemorrhage, as well as liver and spleen necrosis, diarrhea, bleeding gums and blood vomiting, leading to shock & deathLassa Virus
infects house mice. Found in 20% of mice in Washington DC. A febrile illness with flulike myalgia more than meningeal illness. Only about 10% of infected persons show meningeal infection with full recovery. Risk of in utero transmissionLCMV
Bullet-shaped Enveloped helical ss(-)RNA. Transmission by saliva of animal. Pathogenesis - After contact, the virus binds to nicotinic AchR of peripheral nerves or into muscle. It goes by retrograde axoplasmic travel to spinal cord then to brain. Clinical presentation flu-like symptoms followed by neurological symptoms of hydrophobia, seizures, disorientation, hallucination, coma, death. Diagnosis by Negri bodies and RT-PCR. Treatment & Prevention: 1 dose human HRIgG and 4 doses of killed vaccineRabies
Primary - General flu-like (after incubation). Neurological Phase - Discomfort or a prickling or itching sensation at the site of bite, progressing within days to symptoms of cerebral dysfunction, anxiety, confusion, agitation, nuchal rigidity, muscle twitches and hydrophobia, delirium, abnormal behavior, hallucinations, and insomnia.Rabies
Once clinical signs of this disease appear, the disease is nearly always fatal, and treatment is typically supportiveRabies
One dose immediately injected at site of biteHuman Rabies Immune Globulin (HRIG)
Four shots total giving in sequenceRabies Killed Vaccine Series
Outbreaks associated with West Africa. From monkeys or bats to humans. Among humans by direct contact with infected body fluids (esp. blood) or by accidental injection. High risk in handling body disposalEbola
Initial flu-like symptoms (headache and myalgia) are followed by nausea, vomiting, diarrhea, and possibly a rash. Extensive hemorrhage from gastrointestinal tract, results in hypovolemic shock. Death occurs in 50% to 90% of cases depending on strain. Biosafety Level 4 (BSL-4) isolation is requiredEbola


Question Answer
Oval single cellYeast
Tube-like connected cellsHyphae
Single daughter cellsConidia
No separation with no visible cell wallAseptate
Separated with visible cell wall separating cellsSeptate
Septate hyphae, Frilled condidia Aspergillosis
Aseptate hyphae, Ball conidiaZygomycetes (Mucor)
Arthroconidia = articulatedCoccidioides
“Elliptical” MacroconidiaMicroporum
Dimorphic with board based buddingBlastomyces
Arthrocondia at 25 degress C and spherule at 37 degrees CCoccidiodes
Tuberculate condiaHistoplasma
Wheel buddingParacoccidiodes
Budding yeast and pseudohyphaeCandida
Hypha with a capsuleCryptococcus
Condia with acute angle septaeAspergillus
Target ergosterol synthesisAzoles
Directly target ergosterolPolyenes
Can only be given for 2 weeks because it also targets host sterolsAmphotericin B
Primary treatment for fungal pneumoniaItraconazole

Systemic Mycosis

Question Answer
Endemic Dimorphic strict pathogen, “Valley Fever” from San Joaquin Valley in CA, Southwestern USA (CA, AZ, NM, NV), Mexico, Desert soil. Has arthroconidia structure at 25 C and spherule structure at 37 CCoccidioides
Spherule with very thick wallCoccidioides
Dense mass pneumonia, Erythema nodosum “Desert Bumps” and can progress to chronic colonization of the bone marrowCoccidioides Valley Fever
Treatment of primary pneumonia and skin bumps or lesionsItraconazole
Treatment of CNS or Disseminated in AIDS patient. Can only be given for two weeksAmphotericin B
Endemic Dimorphic Strict pathogen. “Darling Disease”.Grows in soil and material contaminated with bird or bat guano. Ohio, Mississippi River Valley of North-Central United States. Has tuberculate conidia structure at 25 C and yeast structure (intracellular) at 37 CHistoplasma
Endemic Dimorphic Strict pathogen. Most pathogenic of the endemic fungi. “North American blastomycosis” . Soil and organic debris. East of Mississippi River. Broad Based Budding YeastBlastomyces
Presents with tuberculosis-like pneumonia and skin lesionsBlastomycosis
South American "blastomycosis,” Brazil. "Paracoccidioidal granuloma” Lung. Lungs, mouth, nose, lymph nodes. Inhaled conidia that convert to multi-polar budding yeast (Pilot Wheel)Paracoccidioidomycosis
Prominent mycotic pathogen among HIV-infected individual. Southeast Asia. Lung, lymphadenopathy, hematogenous dissemination. Intracellular (like Histoplasmosis). Inhaled conidia convert to yeast form with transverse septaPenicillium marneffei

Opportunistic Mycosis

Question Answer
Budding yeast with pseudohyphaeCandida
Generates symptomatic infection with excessive moisture (diaper rash, arm pits, breasts), disturbance of beneficial flora (vaginal infection), low T-cell count (oral thrush and nail infection)Candida
Erythematous papules and pustules, which later coalesce into a beefy red confluent rash with sharp bordersDiaper Dermatitis
Women (healthy) with a history of antibiotics accompanied by itching and/or painful urination with Cottage cheese dischargeVaginal Yeast Infection
AIDS/Immunocompromised patients***CMCC- Chronic MucoCutaneous Candidiasis. Chronic inflammation leads to tissue destructionOnychomycosis
Treatment for onychomycosis and topical candidaNystatin
Systemic candida mostly seen in patients that areNeutropenic
Worldwide, in soil, enriched with pigeon poop. Only in yeast form. Pathogenesis: Inhale YEAST which are ingested by macrophages, capsule inhibits phagocytosis and suppresses cellular/humoral reactionCryptococcosis
Fever, meningismus, visual disturbances, abnormal mental status, seizures, forms “soap-bubble lesions”Cerebromeningeal in AIDS patients
Most common cause of CNS infections in AIDS patientsCryptococcosis
Most common cause of pneumonia in AIDS patients (Defining disease <200cell/ul)Pneumoncystis jirovecii
Presentation: slowly progressing, fever, dry cough (atypical pneumonia), diffuse interstitial infiltrates Diagnosis: sputum, bronchoalveolar lavage (BAL), Giemsa-for trophs, Silver Stain for cyst wall, DFA for bothPnemocystis Pneumonia
Pnemocystis Pneumonia is treated withTMP-SMX (Trimethoprim-Sulfamethoxazole)
Ubiquitous in the environment, especially dust. Only in mold form. Lungs (Inhaled conidia --> Hyphae grows in tissue. Acute Angle branching <45 degrees. Septate hyphae. Presentation allergy asthma in atopic patients (high IgE). Pneumonia in neutropenic patients. Obstructive bronchial aspergillosis. Usually other underlying disease: CF, COPD. Bronchial plugs. Also seen in marijuana smokers. Treatment with VoriconazoleAspergillus
In imaging scans, dense ball with a halo sign around dense ballAspergillus
Inhaling sporangiospores-> systemic. Aseptate hyphae with irregular angles and rounded sporangium. Contaminated A/C system. Skin injection after IV catheter use. Nosocomial infection - Neutropenia and diabetes (esp. ketoacidosis). Subcutaneous - Patients with burns or sign of disseminated infectionZygomyces (Mucor)
Lung + neutropenicAspergillus
Lung + AIDSPneumocystis
CNS + AIDSCryptococcus
Systemic + neutropenicCandida
Rhino-cerebral + diabeticMucor

Cutaneous Mycosis

Question Answer
Collective term for fungal agents that cause cutaneous infections in keratin tissueDermatophyte
A collective term for disease presentation of scaly, puritic localized fungal infectionTinea
Elliptical Macroconidia. Mostly associated with Tinea capitisMicrosporum
Frequent in children (3-7 years old). Lesion can be asymptomatic (M. audouinii, T. tonsurans) or pruritic (zoophilics). Centrifugal plaquesTinea capitis
Numerous elliptical microconidia, borne singly along the hyphae or in clusters. Can produce any of the Tinea conditionsTrichophyton
Erythematous patches of the face and neck show scaling, fragile, lusterless hairs and a tendency to folliculitisTinea barbae
Lesion lasts for days to months with mild pruritis or even no symptoms. Annular plaque that expand in centrifugal pattern. Border with erythematous elevated shape and occasionally small papules. Center of lesion is pale. Lesions -more inflammatory when zoophillic fungiTinea corporis
Involves the groin, buttocks, scrotum and penis. Clinically appears as brown to beefy-red serpiginous (Snake-like), scaly lesions. Common in adult males but seldom occurs in females - Lesions are pruritic and localized in groin area and thighs, and occasionally in buttocks. Large and well-demarcated red, tan or brown plaques with scaling can be seen. The margin are more elevated or active with some pustules or erythematous papules. Centrifugal patternTinea cruris
Distal Subungual. MOST common Fungal Invasion of hyponychlum. Nail thickens and turns yellow or white. T rubrum main causative agent. Crumbling and fragmentation of nailTinea unguium
Most common associated with Tinea pedisEpidermophyton
No microconidia. Macroconidia thin smooth walls of 2-4 cells, borne singly or in clusters. Dumb-bell shape macrocondidia. The most common infection in late childhood or young adults caused by dermatophytesEpidermophyton
Involving most commonly the toe webs and plantar surfaces of the feet. Clinical forms – Moccasin – Interdigital– Vesicular. Interdigital spaces, underspaces of toes, sole, sometimes extending over feet. Clinical Signs - Scales, erythema, cracked skin, blistering, itchingTinea pedis
Lesions characterized by small hypo- or hyperpigmented macules (interfere with production of melanin). Common sites - chest, shoulders, neck, face, back and arms. Patches of discolored skin with sharp borders (edges) and fine scales. In African Americans, there may be loss of skin color in dark skinned individuals (hypopigmentation) or an increase in skin color (hyperpigmentation) in light skinned degrades lipids and produces damage acids that damage melanocytes and cause hypopigmented/hyperpigmented patches, occurs in humid weather, Mild itching Differential: Appears similar to Tuberculoid leprosy however leprosy causes loss of sensation and Pitryrisis causes itchingTinea versicolor
Thermally dimorphic. Has a swollen conidiophores, tear shaped, round conidia, sleeve shapes, rosette form at 25 degrees C. Has a round/cigar-shaped yeast cells at 37 degrees C.Sporothrix schenckii
Subcutaneous tissue and rarely spread systemically. The causative agents are soil organisms introduced into the extremities by trauma (thorn, scrach from cat). Establishes subcutaneous ulcers along the lymphaticsSporotrichosis
Verrucoid, ulcerated and crusted flat or raised 1-3 cm. Single nodule that become more with time. Satellite lesions by auto-inoculation or lymphatics extensive keloid formation. Chronic lesions – “cauliflower like” (years) with black dots, chronic granulomtous inflammatory process. Verrucose lesions are warty and hyperkerototic (thickening of the stratum) corneum, pruriticChromomycosis
Post-traumatic chronic infections. Site(s) - Feet, lower extremities, hands. Findings - Multiple granulomas and abscesses that contain large aggregate of fungal hyphae known as granules or grains. Swelling and draining sinuses containing granules. Abscess formation, it can involve muscle & bone locallyEumycotic Mycetoma

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