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Microbiology Part 2.

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Presentation on theme: "Microbiology Part 2."— Presentation transcript:

1 Microbiology Part 2

2 Mycology – Systemic Mycoses
Histoplasmosis Blastomycosis Coccidioidomycosis Paracoccidioidomycosis

3 These are all dimorphic fungi Mold in the soil, yeast in tissues
Cold = mold, Heat = Yeast All cause pneumonia, can disseminate Tx: ketoconazole or fluconazole for local infection; Ampho B for systemic

4 Mycology – Systemic mycoses
Histoplasmosis Blastomycosis Coccidioidomycosis Paracoccidioidomycosis

5 Histoplasmosis Transmitted by inhalation of asexual spores
Mississippi and Ohio River Valley Causes pneumonia In bird or bat droppings “Histo Hides” (in macrophages)

6 3-5 um

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8 Mycology – Systemic Mycoses
Histoplasmosis Blastomycosis Coccidioidomycosis Paracoccidioidomycosis

9 Blastomycosis East of Mississippi River and Central America
Cases Inflammatory lung disease, which can disseminate to skin and bone Granulomatous nodules “Blasto Buds Broadly” (broad-base budding yeast)

10 5-15um

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12 Mycology – Systemic Mycoses
Histoplasmosis Blastomycosis Coccidioidomycosis Paracoccidioidomycosis

13 Coccidioidomycosis Transmitted by inhalation of asexual spores
Southwestern United States, California San Joaquin Valley Causes pneumonia and meningitis; can disseminate to bone and skin Cases increase after earthquake “Coccidio Crowds” – spherule filled with endospores

14 20-60 um

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16 Mycology – Systemic Mycoses
Histoplasmosis Blastomycosis Coccidioidomycosis Paracoccidioidomycosis

17 Paracoccidioidomycosis
Latin America Budding yeast with “captain’s wheel” appearance Larger than RBC

18 40-50 um

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20 Cutaneous mycoses - Dermatophytes
Tinea versicolor Caused by Malassezia furfur Causes hypopigmented patches by degradation of lipids producing acids which damage melanocytes Occurs in hot, humid weather Tx: topical miconazole, selenium sulfide (Selsun) KOH prep show “spaghetti and meatballs”

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22 Cutaneous mycoses - Dermatophytes
Tinea pedis, cruris, corporis, capitis Caused by Microporum, Trichophyton, and Epidermophyton Pruritic lesions with central clearing resembling a ring See mold hyphae on KOH prep Pets are reservoir Tx: topical azoles

23 Opportunistic Fungal Infections
Candida albicans Systemic or superficial Yeast with pseudohyphae at 20°, and germ tubes at 37° Oral and esophageal thrush in immune compromised Vulvovaginitis Diaper rash Endocarditis (in IVDA) Disseminated candidiasis Chronic mucocutaneous candidiasis Tx: Nystatin for superficial infection, Ampho B for serious systemic infections

24 Psuedohyphae and budding yeast at 20°
Germ tubes at 37° Jagged edges with satellite lesions

25 Opportunistic Fungal Infections
Aspergillus fumigatus Mold with septate hyphae that branch at 45° Allergic bronchopulmonary aspergillosis Lung cavity aspergilloma (“fungus ball”) Invasive aspergillosis in immune compromised and pts with CGD

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27 Opportunistic Fungal Infections
Cryptococcus neoformans Heavily encapsulated yeast In soil, pigeon droppings Culture on Sabouraud’s agar; stain with India Ink Latex agglutination test to detect polysaccharide Ag Cryptococcal meningitis; “soap bubble” lesion in brain

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29 Opportunistic Fungal Infections
Mucor and Rhizopus sp. Mold with irregular nonseptate hyphae branching at wide angles Mostly in ketoacidotic diabetic and leukemic patients Proliferate in walls of blood vessels and cause infarction Rhinocerebral, frontal lobe abscess – rapid spreading

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31 Opportunistic Fungal Infections
Pneumocystis jiroveci Yeast; inhaled Pneumonia in immune suppressed Diffuse and bilateral CXR appearance Dx: lung biopsy or lavage; silver stain Tx: TMP-SMX, pentamidine, dapsone Prophylaxis CD4 <200 Sporothrix schenckii Dimorphic fungus – cigar shaped budding yeast; lives on vegetation Sporotricosis – “Rose gardener’s disease” Local pustule or ulcer; follows lymphatic drainage Tx: itraconazole, or potassium iodide

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33 Antifungals

34 Ampho B Nystatin Azoles
MOA: Binds ergosterol, forms membrane pores allowing leakage of electrolytes Use: Systemic mycoses; intrathecally for fungal meningitis (does not cross BBB) Toxicity: Fever/chills, nephrotoxicity, arrhythmia Nystatin MOA: Binds ergosterol disrupting membrane, too toxic for systemic use Use: “Swish and swallow” for oral thrush, topical for diaper rash and vulvovaginitis Azoles MOA: inhibits fungal sterol synthesis Use: systemic mycoses Toxicity: gynecomastia, inhibits P450

35 Flucytosine Caspofungin Terbinafine Griseofulvin
MOA: inhibits DNA synthesis Use: systemic mycoses with Ampho B Toxicity: Bone marrow suppression Caspofungin MOA: Inhibits cell wall synthesis (inhibits synth of β-glucan) Use: Invasive aspergillosis Terbinafine MOA: Inhibits fungal enzyme squalene epoxidase Use: dermatophytoses Griseofulvin MOA: interferes with microtubule function, disrupts mitosis; deposits in keratin containing tissue Use: Oral for superficial infections; inhibits growth of dermatophytes Toxicity: Teratogen, carcinogenic, increases P450 activity

36 Parasites

37 Single celled organisms
Giardia lamblia Dz: bloating, flatulence, foul-smelling fatty diarrhea, seen in campers Transmission: cysts in water Dx: Trophozoites or cysts in stool Tx: Metronidazole Entamoeba histolytica Dz: Amebiasis – bloody diarrhea, liver abscess, RUQ pain Dx: Serology, trophozoites or cysts in stool Tx: Metronidazole and iodoquinol

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39 Cryptosporidium Toxoplasma gondii
Disease: severe diarrhea in AIDS pts, mild disease in non-immunocompromised Transmission: cysts in water Dx: Cysts on acid-fast stain Prevention by filtering city water Toxoplasma gondii Disease: brain abscess (ring-enhancing lesions); congenital toxo  chorioretinints, hydrocephalus, intracranial calcifications Transmission: cysts in meat or cat feces; crosses placenta Dx: Serology, biopsy Tx: Sulfadiazine + pyrimethamine

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41 Naegleria fowleri Trypanosoma
Disease: rapidly fatal meningoencepalitis Transmission: swimming in fresh water lakes, enter via cribriform plate Dx: Amoebas in spinal fluid Tx: none Trypanosoma T. gambiense, T. rhodesiense Disease: African sleeping sickness = enlarged LN, recurring fever, somnolence, coma Transmission: Tsetse fly Dx: Blood smear Tx: Suramin for blood borne disease; melarsoprol for CNS penetration

42 Trypanosoma cruzi Leishmania donovani
Disease: Chagas disease = dilated cardiomyopathy, megacolon, megaesophagus; South America Transmission: Reduviid bug Dx: Blood smear Tx: Nifurtimox Leishmania donovani Disease: Visceral leishmaniasis (kala azar) = spiking fevers, hepatosplenomegaly, pancytopenia Transmission: sandfly Dx: macrophages with amastigotes Tx: Sodium stibogluconate

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44 Plasmodium – malaria, cycle fever, HA, anemia, splenomegaly
P. vivax/ovale Cycles QOD, dormant form in liver treated with primaquine P. falciparum Severe, cycles QD, RBCs with parasite occlude capillaries in brain, kidneys, lungs P. malariae Transmission: Anopheles mosquito Dx: Blood smear Tx: chloroquine, if resistance use mefloquine; primaquine for dormant form in P. vivax/ovale

45 Trichomonas vaginalis
Babesia Disease: Babesiosis = fever and hemolytic anemia; in NE USA Transmission: Ixodes tick (same as Borrelia of Lyme Dz; may coinfect) Dx: Blood smear; RBC with “Maltese Cross” Tx: Quinine, clindamycin Trichomonas vaginalis Disease: vaginitis = foul-smelling greenish discharge, itching and burning Transmission: sexual Dx: Trophozoites on wet mount Tx: Metronidazole

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47 Helminths - Nematodes Enterobius vermicularis (pinworm)
Food contaminated with eggs; intestinal infection; anal pruritis; scotch tape method Ascaris lumbricoides Eggs visible in feces; intestinal infection; Loffler’s eosinophilic pneumonitis Trichinella spiralis Undercooked meat, usually pork; inflammation of muscle, periorbital edema Strongyloides stercoralis Larvae in soil penetrate skin; intestinal infection; causes vomiting, diarrhea and anemia

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49 Adult worms live in the lumen of the small intestine
Adult worms live in the lumen of the small intestine.  A female may produce approximately 200,000 eggs per day, which are passed with the feces .  Unfertilized eggs may be ingested but are not infective.  Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil).  After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs .  The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed .  Upon reaching the small intestine, they develop into adult worms .  Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female.  Adult worms can live 1 to 2 years.

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51 Acylostoma duodenale, Necator amercanus Dracunculus medinensis
Hookworms; penetrate skin of feet; intestinal infection can cause anemia (Fe deficiency) Dracunculus medinensis In drinking water; skin inflammation and ulceration Onchocerca volvulus Blackflies; hyperpigmented skin and river blindness; Allergic reaction to microfilaria Loa loa Deer fly, horse fly, mango fly; swelling in skin; can see worm crawling in conjunctiva Wuchereria bacrofti Mosquito; blockage of lymphatic vessel; 9mo – 1yr after bite to get elephantiasis Toxocara canis Food contaminated with eggs; granulomas and visceral larva migrans; blindness if in retina

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53 Helminths - Cestodes Taenia solium Diphyllobothrium latum
Pork tape worm; ingested larvae encysted in undercooked pork; ingestion of eggs causes cysticercosis, and neurocysticercosis Diphyllobothrium latum Fish tape worm; ingestion of larvae in freshwater fish; B12 deficiency anemia Echinococcus granulosus Eggs in dog feces, Hydatid cyst (anaphylactic response to echinoccocal Ag in cyst)

54 Helminths - Trematodes
Schistosoma Snails are host; cercariae penetrate skin; cause granulomas, fibrosis, inflammation of spleen and liver. S. hematobium SCC of bladder Clonorchis sinensis Undercooked fish; inflammation of biliary tract  pigmented gallstones; cholangiocarcinoma Paragonimus westermani Undercooked crab meat; inflammation and 2° bacterial infection of lung  hemoptysis Squamous cell CA

55 Viruses

56 Vaccines Live attenuated Killed Recombinant
Smallpox, VZV, yellow fever, Sabin’s polio, MMR Killed Rabies, Influenza, Salk polio, HAV Recombinant HBV, HPV

57 DNA Viruses Herpesviruses
HSV-1: herpes labialis; keratoconjunctivitis; gingivostomatitis; temporal lobe encephalitis HSV-2: herpes genitalis; neonatal herpes VZV: Chickenpox, shingles EBV: Mono (positive monospot), Burkitt’s CMV: infection in immunosuppressed especially transplant recipient; congenital infections; mono (negative Monospot); Owl’s eye inclusions HHV-6: roseola (exanthem subitum); high fevers for several days that can cause febrile seizure, followed by diffuse macular rash HHV-7: clinically insignificant HHV-8: Kaposi’s sarcoma Mono = fever, hepatosplenomegaly; lymphadenopathy particularly posterior cervical nodes

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59 Dx of HSV Tzanck test – smear of opened vescicle to detect multinucleated giant cells For HSV-1, HSV-2, VZV

60 Hepadnavirus: Adenovirus Parvovirus Papillomavirus Polyomavirus
HBV; acute or chronic hepatitis; vaccine; has reverse transcriptase but not retrovirus Adenovirus Febrile pharyngitis, pneumonia, conjunctivitis Parvovirus B19: aplastic crisis in sickle cell, “slapped cheek” (erythema infectiosum, 5th disease); RBC destruction leads to hydrops fetalis Papillomavirus HPV, warts, CIN, cervical cancer Polyomavirus JC: progressive multifocal leukoencephalopathy in HIV Poxvirus Largest DNA virus Smallpox, vaccinia (milkmaid’s blisters), Molluscum contagiousum

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62 RNA Viruses Picornaviruses Reovirus
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, HAV Rhinovirus: common cold Coxsackie: myocarditis, hand foot and mouth disease, aseptic meningitis Reovirus Segmented, dsRNA Rotavirus: infantile gastroenteritis; villous destruction and atrophy leads to decreased absorption for Na and water

63 Flaviviruses Orthomyxovirus HCV, Yellow Fever, Dengue, SLE, West Nile
Yellow Fever: transmitted by Aedes mosquito, causes high fever, black vomitus, jaundice; councilman bodies in liver (hepatocytes undergoing apoptosis) Orthomyxovirus Segmented Influenza – hemagglutinin (viral entry), neuraminidase (progeny release) Genetic shift = reassorment (pandemics) Genetic drift = minor changes based on random mutations (epidemic)

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65 Togavirus Paramyxoviruses Rhabdovirus Rubella, EEE, WEE
Rubella: German measels, 3 days, fever, lymphadenopathy, arthralgias; TORCH Paramyxoviruses Paraflu, RSV, Rubeola, Mumps Measles: Koplik spots, 3 C’s (cough, coryza, conjunctivitis), rash spreads head to toe Mumps: Parotitis, orchitis, aseptic meningitis Rhabdovirus Rabies Negri bodies (cytoplasmic inclusions in neurons); bullet shaped; long incubation; retrograde migration Fever, malaise  agitation  photophobia, hydrophobia  paralysis, coma  death

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67 Hepatitis Viruses HAV HBV HCV HDV HEV
Fecal-oral, short incubation, no carriers, usually asymptomatic HBV Parenteral, sexual, materal-fetal transmission; long incubation, carriers HCV Blood transmission, resembles HBV in course and severity (Chronic, cirrhosis, HCC); carriers; post-transfusion hepatitis; IVDA HDV Requires HBV surface Ag; co-infection or superinfection; carriers HEV Enteric transmission; water-borne epidemics; course similar to HAV; high mortality in pregnant women

68 Hepatitis Serology Markers
IgG HAV Ab = prior infection, protective IgM HAV Ab = active HAV infection HBsAg = active disease, carrier state HBsAb = immunity; recovered (dz or exposure) HBcAg = New dz HBcAb = positive during window pd; IgM is sign of recent disease, IgG signifies chronic disease

69 HIV Diagnosis ELISA = RULE OUT TEST HIV PCR/viral load
Positive test is confirmed with Western Blot (Rule In test) Falsely negative test in first 1-2 months of infection HIV PCR/viral load Monitor effects of therapy AIDS diagnosis is CD4 count ≤200, or presence of AIDS defining illness


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