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Opportunistic Fungi & Pneumocystis

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Presentation on theme: "Opportunistic Fungi & Pneumocystis"— Presentation transcript:

1 Opportunistic Fungi & Pneumocystis
Doç.Dr.Hrisi BAHAR

2 Opportunistic organisms
Opportunistic organisms are normal resident flora that become pathogenic only when the host's immune defense reduses. In immunosuppressive therapy, In a chronic disease such as diabetes mellitus, During steroid or antibacterial therapy that upsets the balance of bacterial flora in the body.

3 Opportunistic Mycosis
Opportunistic mycosis is a fungal or fungus-like disease occurring in an animal or human’s with a compromised immune system. Opportunistic fungal infections are: Candidiasis Aspergillosis Cryptococcosis

4 CANDIDA SP Candidia can infect skin, mucosa, or internal organs
It is as Yeast Like fungus It is an important cause of opportunistic fungal infection.

5 Candida ► Candida is found in normal flora,exist in mouth, gastrointestinal tract, vagina, skin in 20 % of normal individuals. ►Colonization increases with age,in pregnancy, hospitalization….. ►Candida is an important etiological agent presenting as opportunistic infection in Diabetes and HIV patients.

6 Morphology and Culturing
The shape is ovoid or spherical budding cells and produces pseudo mycelium Routine cultures are done on Sabouraud's dextrose agar, Grow predominantly in yeast phase A mixture of yeast cells and pseudo mycelium and true mycelium are seen in vivo and nutritionally poor media.

7 Macroscopic and Microscopic appearance of Candida spp

8 Pseudohypal structures in Candida

9 Candida as Pathogenic fungi
Systemic Candidosis Occurs in Patients who carry more yeasts in mouth, and gastrointestinal system, Predisposed with individuals 1. On antibiotic or/and steroid therapy 2. Immunosupressed 3. Recipients with organ transplantation 4. Infancy – Old age – Pregnancy 5. Diabetes mellitus 7. Zink and iron deficiencies

10 Pathogenesis and Pathology
Mucosal infections occur superficially –Discrete white patches on mucosal surface. Can affect tongue Infants and old persons are affected In Immune compromised /AIDS, oral candidois is commonly seen Vaginal candidosis causes itching soreness white discharge, white colored lesions, In pregnancy in advanced stage, Majority experience one episode in a life time

11 Important species of Candida in human infections
C.albicans C.tropicalis C.glabrata C.krusei

12 Infections with Candida

13 Oral Thrush produced by Candia albicans

14 Many cases of AIDS are suspected by observation of oral cavity

15 Laboratory Diagnosis Skin scrapings, Mucosal scrapping,
Vaginal secretions Culturing blood and other body fluids, Observations Microscopic observation after Gram staining. Presence of Gram + yeast cells.

16 Laboratory Diagnosis Isolation of Candida from various specimens
Easier to culture on Sabouraud's dextrose agar Serology, molecular methods,PCR

A capsulated yeast – A true yeast.. A sporadic disease in the past. Most common infection in AIDS patients.

18 Structure of C.neoformans

19 Morphology A true yeast Round 4 – 10 microns
Surrounded by Mucopolysaccharide capsule. Thick in vivo Negative staining with India Ink and Nigrosin 60% of the infected prove positive by India Ink preparation on examination of CSF KoH preparations in Sputum and other tissues, PAS and Mucicaramine staining helps confirmation.

20 C.neoformans in India ink preparation

21 Culturing CSF-Culturing on Sabouraud's agar, and incubated at 370 C for upto to 3 weeks Cultures appear as creamy, white, yellow brown colored *Simple urease test helps in confirming the isolate.

22 Cryptococcus neoformans Serotypes
A true yeast 4 serotypes - A,B,C,D A and D - C.neofromans var neoformans B and C - C.neoformans var gatti. Many infections are caused by C.neofromans var neoformans. Found in wild/Domesticated birds. Pigeons carry C.neofromans, Birds do not get infected.

23 Life cycle of C.neoformans

24 Pathogenesis Enters through lungs by inhalation of “basidiospores” of C.neoformans Enters deep into lungs, pulmonary infections can occur. Men acquires more infections, and women less infected. Self limiting in most cases, Present as discrete nodules - Cryptococcoma.

25 Pathogenesis Can infect normal humans
Abnormalities of T lymphocyte function aggravates, the clinical manifestations. In AIDS 3-20% develop Cryptococcosis. Present with chronic meningitis , meningo encephalitis Manifest with – head ache low grade fever, Visual abnormalities ,Coma – fatal Treatment reduces the morbidity and cure in non immuno supressed expected.

26 Clinical manifestation
1.Pulmonary Cryptococcosis 2.Central Nervous System Cryptococcosis 3.Cutaneous Cryptococcosis 4.Cryptococcosis of bone 5.Ocular Cryptococcosis 6.Other forms (Cryptococcus neoformans is often isolated from urine of patients with disseminated infection. Occasionally, signs of pyelonephritis or prostatitis may be observed. Other rare forms of cryptococcosis include adrenal cortical lesions, endocarditis, hepatitis, sinusitis, and localized oesophageal lesions) .

27 Laboratory Diagnosis. CSF Microscopic observation under India Ink preparation Direct microscopy - Gram staining Cultures on Sabouraud dextrose agar, Serological tests for detection of Capsular antigen CSF findings mimic like Tuberculosis IN CSF - latex test for detection of Antigen Blood cultures, ELISA

28 Avoid contact with Birds
Treatment Immune competent Fluconazole,Itraconazole Immune Deficient Amphotericin B,Flucytosine AIDS patients are not totally cured , Relapses are frequent with fatal outcome. Rapid resistance develops with Fluconazole. Avoid contact with Birds

29 ASPERGILLUS SP In nature > 100 species of Aspergillus exist, Few are important as human pathogens 1 A.fumigatus 2 A.niger 3 A.flavus 4 A.terreus 5 A.nidulans

30 Fungal spores enters through respiratory tract

31 Morphology Cultured as Mycelial fungus
Separate hyphae with distinctive sporing structures Spore bearing hyphae – Conidiophores terminates in a swollen cell vesicle surrounded by one or two rows of cell ( Streigmata ) from which chains of asexual conidia are produced

32 Pathogenesis Clinical presentations
Allergic Aspergillosis – Atopic individuals, with elevated IgE levels 10-20% of Asthmatics react to A.fumigatus Allergic alveoitis follows particularly heavy and repeated exposure to larger number of spores Maltsters Lung – causes allergic alveolitis, who handle barley on which A.claveus has sporulated during malting process

33 Pathogenesis Aspergilloma – A fungal ball, fungus colonize Preexisting (Tuberculosis ) cavities in the lung and form compact ball of Mycelium which is later surrounded by dense fibrous wall presents with cough, sputum production Haemoptysis occurs due to invasion of blood vessels

34 Pathogenesis Invasive Aspergillosis occurs in immunocompromised host
with underlying disease Neutropenia is the most common predisposing factor A.fumigatus is the most common infecting species In bone marrow recipients leads to high mortality Fungus invades blood vessels, causes thrombosis septic emboli Can spread to Kidney and heart.

35 ZYGOMYCETES The ilness is called Zygomycosis,also called as Mucor Mycosis or Phycomycosis Saprophytic mould fungi Major Causative agents of Zygomycosis Rhizopus Mucor Absidia

36 Morphology Majority are with broad aseptate mycelium with many number of asexual spores inside a sporangium which develops at the end of the aerial hyphae

37 Mucor Microscopy ► Non septate hyphae ►Having branched sporangiophores
with sporangium at terminal ends

38 Rhizopus Microscopy ► Shows non septate hyphae ► Sporangiophores in
groups are above the Rhizoids

39 Important Clinical Manifestations
Rhino cerebral Zygomycosis associate with Diabetus mellitus, leukemia, or lymphomas Causes extensive Cellulitis, and tissue destruction.

40 Mucormycosis Cellulitis causes extensive tissue destruction.
Spread from nasal mucosa to turbinate bone,paranasal sinuses ,orbit, and brain Rapdily fatal if untreated

41 Laboratory Diagnosis Histopathology more reliable than culturing

42 Pathology and Pathogenesis
Spread from nasal mucosa Spread to turbinate bones,para nasal sinuses , orbit, brain Associated with uncontrolled diabetes mellitus In leukemia patients , Lymphoma patients, Leads to fatal outcome, Improved with anti fungal treatment. Spread to lungs disseminated infection,.

43 Treatment Early Diagnosis highly essential for effective cure
High doses of I V Amphotericin B Surgical interventions Control of Diabetes a basic requirement for better clinical outcome

44 PNEUMOCYSTIS Identified as the most Important opportunistic fungal infection in persons with impaired immune systems & AIDS

45 Pneumocystis Pneumocystis is a genus of unicellular fungi found in the respiratory tracts of many mammals and humans. The organism was first described in 1909 by Chagas and then a few years later by Delanöes, who ultimately named the organism in honor of Dr. Carini after isolating it from infected rats. The name was Pneumocystis carinii

46 Pneumocystis Years later, Dr. Otto Jirovec and his group isolated the organism from humans, and the organism responsible for P.carinii pneumonia (PCP) was renamed after him and P.carinii change to Pneumocystis jiroveci

47 Pneumocystis The taxonomic classification of the Pneumocystis genus was debated for some time It was a trypanasome then a protozoan and today it is accepted as a fungus. The organism is found in 3 distinct morphologic stages, as follows: The trophozoite (trophic form), The sporozoite (precystic form)and the cyst, which contains several intracystic bodies

48 Life cycle of P.Jiroveci

49 Pathogenesis Pneumocystis jiroveci pneumonitis (PCP) is a common opportunistic disease that occurs almost exclusively in persons who have profound immunodeficiency. PCP was and still is the most common life-threatening opportunistic infection occurring in patients with HIV disease.

50 Pathogenesis ►The portal of entry for P carinii has not been firmly established; however, because the organism has been found only in the lung, inhalation is a likely mode of transmission. ►In most individuals, the organism is dormant and sparsely dispersed in the lung, with no apparent host response (latent infection). ►In susceptible (immunocompromised) hosts, the organism occurs in massive numbers. Pathogenesis

51 Clinical manifestation
► Tachypnea and fever are consistent features of the pneumonitis, and diffuse bilateral alveolar disease can be observed by radiography. ► Diagnosis requires the identification of P carinii in pulmonary tissue or lower airway fluids. ► Such specimens may be obtained by lung biopsy, inducement of sputum, bronchoalveolar lavage, or needle aspiration of the lung. ► The Gomori, Giemsa, fluorescence-labelled antibody, or toluidine blue stains may be used to identify the organism. Clinical manifestation

52 Pneumocystis carinii
Title: EM Image of Pneumocystis carinii Disease(s): Pneumocystis pneumonia Legend: An electron micrograph of P. carinii cyst from rat lung tissue. Genus/Species: Pneumocystis carinii Image Type: Microscopic Morphology

53 Pneumocystis carinii
Title: Pneumocystis carinii-infected Rat Lung Tissue   Disease(s): Pneumocystis pneumonia Legend: An H&E stain of a rat lung infected with P. carinii. It does not show any organisms, but shows the proteinaceous exudate which results from Pneumocystis infection, and ultimately causes reduced gas exchange. Genus/Species: Pneumocystis carinii Image Type: Microscopic Morphology

54 Pneumocystis carinii
Title: Pneumocystis carinii Silver Stain Disease(s): Pneumocystis pneumonia Legend: A silver stain of P. carinii cysts from rat lung tissue showing the typical 'deflated ball' shape. Genus/Species: Pneumocystis carinii Image Type: Microscopic Morphology

55 Pneumocystis carinii
Title: EM Image of Pneumocystis carinii Disease(s): Pneumocystis pneumonia Legend: An electron micrograph of a P. carinii troph from rat lung tissue, showing its binding to a type I pneumocyte. Genus/Species: Pneumocystis carinii Image Type: Microscopic Morphology

56 Treatment pentamidine isethionate trimethoprim-sulfamethoxazole
Four drugs currently available for therapy of P carinii pneumonitis are: pentamidine isethionate trimethoprim-sulfamethoxazole atovaquone trimetrevate Trimethoprim-sulfamethoxazole is preferred because of its low toxicity and greater efficacy.

57 Pencillium marneffi Causes serious disseminated infection, Papular skin lesions in AIDS Common in South east Asia

58 Morphology A dimorphic fungi Mould at 250 c Yeast at 370c
Intracellular yeast like appearance as in Histoplasmosis The fungi are associated with Bamboo rat

59 Typical microscopic appearance of P.marneffi

60 Pathology and Pathogenesis
Inhalation of Conidia Primary site of infection RES Present with Chills, Fever Malaise Hepato splenomegaly Probably AIDS defining infection

61 Laboratory Diagnosis Microscopy Tissues, skin Lymph node bone marrow
Use of special stains Culturing on Sabouraud dextrose agar Immunoblot methods PCR

62 Treatment Some times Amphotericin B may be considered.
Major Antifungal treatments are speculative

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