Microbiology Of Pulmonary Infections

MICROBIOLOGY – CARDIO/PULMONARY BY MARTINEZ, VIERA & GUZMAN – AT STILL UNIVERSITY SCHOOL OF OSTEOPATHIC MEDICINE

ENDOCARDITIS CAUSING ORGANISMS TYPE

Strep. Viridians

Staphylococcus Aureus

Staphylococcus Epidermitis Candida Albicans Aggregatibacter species (new) Cardiobacterium hominis Rickettsiae

Rickettsia Rickettsi

Coxiella burnetii

Features

Gram + cocci Gram +,cocci,capsule, protein A in the cell wall, yellow,creamy, grapelike clusters on culture

Yeast endogenous to our mucous membrane normal flora Gram -, rods, Facultative anaerobes

Gram -,rods, Facultative anaerobes, Three Genera; Rickettsia,Ehrlichia,Coxiella->Obligate intracellular bacteria, Arthropod borne (lice,ticks, fleas,mites, Obligate intracellular bacteria

Endospore; very unique to the Rickettsia family

Disease

SUBACUTE ENDOCARDITIS, Dental carries, Brain or Liver abscesses ACUTE ENDOCARDITIS, Abcesses,pyogenic infections (endocarditis, osteomyelitis), food poisoning, toxic shock syndrome,scalded skin syndrome

Clinical diagnosis

Catalase -, Facultative anaerobe, α-hemolytic, Optochin Resistant Coagulase +, Catalase +, βhemolytic, novobiocin sensitive, ferment mannitol

Pathogenesis

Extracellular dextran helps bind to heart valve Rapid growth, protein A (antiphagocytic), enterotoxin (watery diarrhea), toxic shock syndrome toxin; exfoliation, αtoxin;coagulase *Most common cause of Endocarditis in IV Drug Abusers

Prosthetic Valve – first year post op Forms pseudohyphae and true hyphae (when it invades tissue) Endocarditis--> A. actinomyecetecomitans, A. aphrophilus Subacute bacterial endocarditis

Endocarditis  IV drug abusers

Best visualized with Giemsa

Rocky Moutain spotted fever; vasculitis, rash spreads from extremities to thorax

Pneumonia Q fever

Weil-Felix reaction (agglutination when patient's serum mixed with OX strain of Proteus Vulgaris)

Invasion of endothelial lining, transmitted by Dermacentor ticks

Non Arthropod transmission;Aerosilized

LOBAR PNEUMONIA Bacteria

Streptococcus Pneumoniae

Features Gram + diplococci; “Lancet shaped”encapsulated, Facultative anaerobe

Clinical diagnosis α-hemolytic, Optochin and Bile sensitive,

Pathogenesis Capsule

Quellung test positive, catalase negative

Klebsiella Pneumoniae

Gram – rod,

Indole negative

Encapsulated

Ferments lactose

Characteristics The most common bacterial pneumonia etiology. Lobar pneumonia Community acquired; elderly or debilitated patient, Otitis Media, Meningitis

Complications Lung abscess

Red currant jelly sputum; color due to O antigen.

Necrosis of alveolar wall with abscess formation

Empyema

Broncho pneumonia Nonmotile Most often seen in alcoholics and diabetics

facultative anaerobe BRONCHOPNEUMONIA

Staphylococcus Aureus

Gram +,cocci, capsule, protein A in the cell wall, yellow, creamy, grapelike clusters on culture

Coagulase +, Catalase +, βhemolytic, novobiocin sensitive, ferment mannitol

Haemophilus Influenzae

Gram – coccobacillus

Grown on Chocolate agar,

encapsulated facultative anaerobe

Positive Quellung test; due to capsule

Rapid growth, protein A (antiphagocytic), enterotoxin (watery diarrhea), toxic shock syndrome toxin; exfoliation, α-toxin; coagulase, hemolysins Leukocidins, penicillinase, hyaluronidase,staphylokin ase Capsule,

Broncho pneumonia Most commonly in IVDA, elderly and hospitalized patients, chronic lung disease, cystic fibrosis

Attachment pilli,

…also causes: Broncho pneumonia, Meningitis in infants and children, may occur in adults with COPD

IgA protease

Abscess formation or empyema not common

MOST COMMON CAUSE OF EPIGLOTTITIS

Legionella Pneumphila

Pseudomonas Aeruginosa

Gram - bacillus

Diagnosis:

Stains poorly

Dieterle silver stain

Charcoal Yeast Extract

Direct Fluorescent Antibody (DFA)

Gram - rod; appears bluegreen, grape like odor

Facultative Intracellular parasite, catalase and oxidase positive, produces beta lactamases

Infection through inhaled aerosol from stored water, most commonly from AC conditioners

“Foamy Macrophage”

TREATMENT: AZITHROMYCIN OR LEVOFLOXACIN

Capable of growing in diesel or jet fuel, causes corrosion

Nosocomial pneumonia Immunocompromised

Pontiac fever Legionnaires’ disease: Atypical pneumonia

Focal hemorrhage and necrosis

AIDS Cystic fibrosis

INTERSTITIAL PNEUMONIA – PRIMARY ATYPICAL No cell wall Mycoplasma Pneumoniae

****Nonspecific cold agglutinins

Protein P1-adhesion to respiratory epithelium

“Fried egg appearance” on culture

“Walking pneumonia” ; it usally occurs in children and young adults, may occur in epidemics

Encephalitis Erythema multiforme

TREATMENT: DOXYCYCLINE ARYTHROMYCIN Fried Egg Appearance

Respiratory Syncytial Virus (RSV) Belongs to paramyxovirus family

Subgrouping determined by envelope F and G glycoproteins.

Can survive on surfaces for up to 6 hours.

Parainfluenza Virus Belongs to paramyxovirus family (others are Measles,

the causative agents of nearly 40% of acute respiratory infections in infants and children (second to RSV).

Transmitted via large droplets, fomites, and hands; enters through the eyes and nose. Infected cells (epithelium specificity) form syncytia (multinucleated cells).

Infection limited to respiratory tract

Reinfection occurs throughout life with repeat milder infections limited to upper RT.

MOST common cause of upper and lower RTI in infants/young children

Treatment: Ribavirin

**MOST common cause of Bronchiolitis

MOST COMMON CAUSE OF CROUP ALSO CAUSES: Common Cold, bronchitis, and bronchopneumonial; usually accompanied by a hoarse or "barking" cough, sometimes with a swollen epiglottis

Mumps and RSV)

Influenza Belongs to orthomyxovirus family

Is caused by influenza viruses types A and B (but not C) transmitted by airborne droplets.

Enveloped; -, ssRNA MAJOR Surface Angtens for Subtyping: • Hemagglutinin • Neuraminidase Serotyping is based on the M and NP proteins

PNEUMOCYSTIS JIROVECI

Replication: • Cap-Snatching • Synthesis of viral mRNA and RNA genome occurs in nucleus Antigenic Variability: • Antigenic Drift: occurs every year • Antigenic Shift: occurs every 10-20years (only type A) Not transmitted person to person; may be caused by activation of preexisting dormant cells in lung

One of most important fungal agent in AIDS patients **Obligate Extracellur parasite Does NOT contain ergosterol in cell membrane. Can NOT be cultivated, diagnosis rely on microscopic examination.

FAMILY CHLAMYDIACEAE

Obligate intracellular Gramnegative bacteria; small, roundto-ovoid. The cell envelope consists of two lipid bilayers (with LPS)>>> but contains NO peptidoglycan, or muramic acid.

Cysts of P. jiroveci in the lung; SILVER STAIN*

Elementary bodies: metabolically inactive, infectious forms.

Symptoms: common cold, pharyngitis, tracheobronchitis, and bronchiolitis or croup in children.

Diagnosis: Silver-Staining Cyst in Bronchial alveolar lavage fluids or biopsy

Mainly infection of lung tissue; 100% fatal if untreated. Pneumocystis Carrini Pneumonia*interstitial Pneumonia X-RAY: Patchy Infiltrative (ground glass appearance)

Treatment: Trimethoprim/Sulfamethoxazole Chlamydophila pneumoniae: Respiratory infections: atypical pneumonia.

Reticulate bodies: metabolically active, noninfectious forms

Chlamydophila psittaci : Respiratory infections: severe bronchopneumonia with localized infiltration of inflammatory cells, necrosis, and hemorrhage.

c.pneumoniae (pear shaped)

FUNGI – DIMORPHIC Histoplasma Capsulatum

*Giemsa Stain

Inhalation of Histoplasma capsulatum hyphae containing spores from soils contaminated with bird droppings or bat guano Tissue form: Yeast Enviornmental form: Hyphae Microconidia

Leading to infection of macrophages and histocytes; infection of reticuloendothelial system

Occurs throughout the Mississippi and Ohio River valleys

Disease: Fungus Flu Symptoms: flu-like, weight loss and night sweats resemble TB. Chronic infection in immunocompromised individuals leads to hepatosplenomegaly

Blastomyces Dermatitidis

More common in males than in females or children.

Endemic Region:Mostly in South Central and South Eastern U.S.

Tissue Form: Broad Based Budding Yeast Environmental form: hypha with conidia Coccidioides Immitis

Mold phase: Segmented arthroconidia found in the environment Spherule filled with endospores, typical structures formed in infected tissues

Paracoccidioides Brasiliensis

= South American blastomycosis

*Appears to be associated with Rotton Wood Broad Based Budding Yeast (pic) Possible chronic pulmonary infection or disseminated infection (meninges, soft tissues, joints, and bone). Endemic Region: Southwestern U.S. – So. California(especially San Joaquin Valley), Arizona, New Mexico, Texas, Nevada 90% infected are males

Disease: Blastomycosis Acute and chronic pulmonary disease Disseminated Disease: Progressive pulmonary disease may occur with further dissemination to skin, bone, and genitourinary tract. Disease: Coccidiodmycosis (Valley fever) caused by C. Immitis and Coccidioides posadasii influenza-like illness with fever, cough, headaches, rash, and myalgias

Sperule PARACOCCIDIOIDES AND PARACOCCIDIOIDOMYCOSIS An asymptomatic to a subclinical, symptomatic or chronic infection. Disseminated paracoccidioidomycosis affects: reticuloendothelial system, skin, and mucous membranes (most common: mouth and nose).

OPPORTUNISTIC MYCOSIS Cryptococcus neoformans

an environmental yeast **Encapsulated Yeast Reproduces by budding Present in soil contaminated with bird excreta

Aspergillus fumigatus

filamentous mold in dust and soil.

surrounded by a huge polysaccharide capsule ( major virulence factor) in tissue

India ink preparation of CSF: encapsulated yeast cells; diagnostic of cryptococcus neoformans meningitis

Yeasts inhaled into the alveoli and begins to produce the polysaccharide capsule

Aspergilloma: a mycelial ball (cotton ball) formed in the lung cavity; Hospital outbreak due to construction reported. **Hemoptysis

V-SHAPED

“Soap Bubble Lesion”  Mucoid Clear Capsule

Aspergillus flavus (found growing on peanuts) produce Aflatoxins B1 is a potent carcinogen.

Acute invasive aspergillosis (most severe and fatal) results in the spread from the lungs to brain, GI, etc. Other primary infection site: eye, ear, nose (pneumonia), and skin. Treatment: Amphotericin B

Rhizopus and Rhizomucor filamentous, found in soil, plants, and decaying fruits

RIGHT ANGLE BRANCH, NOT SEGMENTED



Restricted to burn, leukemia, DM population.

Cause mucocutaneous and rhinocerebral (fatal within a week) infections, septic arthritis, dialysisassociated peritonitis, renal infections, gastritis, and pulmonary infections.