Microbio review (Kinder) Flashcards

Question

Yersinia pestis

Answer 1

Gram negative coccobacillus, microaerophilic, nonmotile, and non spore forming Transmission cycles involve rodents and fleas, which act as vectors. Prairie dogs are a common host Clinical Manifestations of Plague - Bubonic - Septicemic - Pneumonic

Answer 2

Swollen, tender lymph nodes (buboes) closest to site of initial infection Fevers, chills, myalgia, arthralgia, headache, malaise, and prostration Untreated patients have continued fever, tachycardia, agitation, confusion, delirium, and convulsions

Answer 3

Nausea, vomiting, diarrhea, and abdominal pain Disseminated intravascular coagulation Hypotension, renal failure, and obtundation ARDS

Answer 4

Fever, cough, chest discomfort, tachycardia, dyspnea, bacteria laden sputum, chills, headache, myalgias, weakness, and dizziness Respiratory distress, hemoptysis, cardiopulmonary insufficiency, and circulatory collapse Death within 24 hours of symptoms

Answer 5

Streptomycin for pneumonic plague Tetracyclines for bubonic plague Chloramphenicol for meningitis

Answer 6

Spirochete with terminal hook Identified on dark field microscopy or silver staining Obligate aerobe Clinical Manifestations Weil’s Disease: Pulmonary Hemorrhage Syndrome Reservoir: Persistent renal carriage from rodents, dogs, pigs, cattle, and sheep Colonizes renal tubules, excreted in urine, and survives for weeks to months in the environment Transmission: Penetrates the skin or mucous membranes during contact with contaminated water, soil, or vegetation

Answer 7

``` Early phase: First 3-7 days Fever, myalgia, and headache Nausea, vomiting, abdominal pain, diarrhea, cough, and photophobia Muscle tenderness Rash Conjunctival suffusion ``` ``` Late Phase: Weil’s Disease Jaundice Acute hemorrhage Renal Failure Severe thrombocytopenia GI bleeding Pulmonary Hemorrhage Myocarditis Aseptic meningitis ```

Answer 8

Diagnosis Agglutination test Treatment Doxycycline Penicillin Prevention Doxycycline post-exposure

Answer 9

``` Encapsulated gram negative coccobacilli Aerobic or facultative anaerobic Grows on chocolate agar X(hemin) Factor and V(NAD) Factor Nasopharynx of adults and children Transmission: respiratory droplets H influenza type b was most common cause of meningitis in young children prior to effective vaccines ```

Answer 10

Meningitis Children under 5 years old and in adults with skull trauma or CSF leaks Type B strains Diagnosis made by detecting PRP capsular antigens in CSF Epiglottitis Life threatening infection in children that usually occurs in children younger than 5. Symptoms include fever, drooling, dysphagia, and respiratory distress with stridor Course is rapid over a couple of hours Lateral neck film used for diagnosis ``` Pneumonia: Fever, cough, and lobar consolidation Parapneumonic effusion and empyema Diagnosed by blood culture or culture from pleural fluid Smoking – risk factor ``` Bronchitis Risk factor is chronic lung disease ( COPD) Acute Sinusitis Otitis Media

Answer 11

Treatment: 3rd generation cephalosporin for meningitis Prevention Conjugate capsular polysaccharide-protein vaccine effective for type b disease Antibiotic prophylaxis in nonimmunized household or daycare contacts of patients with H influenza type b Rifampin

Answer 12

``` Gram-positive bacillus – club shaped Non-spore forming Aerobic Reservoir: Throat and pharynx Transmission: Bacterium or phage via respiratory droplets ``` Respiratory Diphtheria Incubation of 1-7 days Sore throat, malaise, and fever Pharyngeal erythema followed by tonsillar exudate Exudate changes into a grayish membrane that is tightly adherent and bleeds on attempted removal Cervical adenopathy – Bull Neck Stridor Extension of membrane can lead to airway obstruction Myocariditis, recurrent laryngeal nerve palsy, and peripheral neuritis ``` Treatment: Erythromycin Antitoxin Prevention: Vaccination with toxoid vaccine ```

Answer 13

Weakly gram-negative pleomorphic rod Facultative intracellular Requires cysteine and iron ( Charcoal yeast extract) Water organism, amebae, air-conditioning water cooler tanks Transmission: aerosols from contaminated air-conditioning, no human to human transfer Risk Factors: smokers over age 55 with high alcohol intake and immunosuppression Legionaire’s disease Fevers, malaise, cough, chills , dyspnea, myalgias, * headache, chest pain, and diarrhea.** Myalgias, severe headaches, and diarrhea distinguish it from other pneumonias Mental Confusion Pontiac Fever Fever, sore throat myalgia, headache, and extreme fatigue Short duration, lasting on average 3 days Diagnosis Antigen urine test DFA ( direct fluorescent antibody) Treatment Fluoroquinolones, azithromycin, or erythromycin + rifampin for immunocompromised patients Drug must penetrate human cells

Answer 14

Smallest free-living bacteria No cell wall – unaffected by cell-wall inhibiting antimicrobials such as B-lactams Sterol containing membrane Requires cholesterol for culture Transmission: respiratory droplets, close contact, families, military recruits, dorms Highest incidence age 5-20 years old ``` Respiratory Infection 2-3 weeks incubation Fevers, malaise, headache, and cough 5-10% progress to tracheobronchitis or pneumonia Cough usually non-productive Walking pneumonia ``` Diagnosis Primarily clinical diagnosis Positive cold agglutinins - positive in 65% of cases Treatment Macrolides: erythromycin, azithromycin, and clarithromycin Tetracyclines

Answer 15

typical pneumonia ``` Gram positive diplococcus, lancet shaped Facultative anaerobe, grows on blood agar plates alpha hemolytic Optochin sensitive Lysed by bile ``` Reservoir – human upper respiratory tract Transmission – respiratory droplets Pathogenesis: Polysaccharide capsule Risk Factors Influenza infection, COPD, CHF, Alcoholism, and asplenia Pathobiology Initially colonizes the nasopharynx then aspirated ``` Clinical manifestations: Typical Pneumonia Most common cause Shaking chills, high fever, chills, rigors, lobar consolidation, blood tinged (rusty) sputum Adult meningitis Most common cause in adults Otitis media and sinusitis Most common cause in children ``` Treatment of pneumonia Beta lactams Macrolides Fluoroquinolones Treatment of meningitis 3rd generation cephalosporins Vancomycin added if penicillin resistant

Answer 16

``` Gram positive cocci in clusters Catalase positive Coagulase positive Beta hemolytic Small yellow colonies on blood agar Ferments mannitol ``` Reservoir – nasal flora in 25% of population ``` Transmission Hands Sneezing Surgical wounds Contaminated food = Custards = Potato salad = Canned meats ``` Over 50 virulence factors including adhesins, toxins, enzymes, surface-binding proteins, and capsule polysaccharides Pathogenesis from tissue invasion and toxin mediated 3 toxin mediated diseases - Staphylococcal food poisoning - Staphylococcal toxic shock syndrome - Staphylococcal scalded skin syndrome Clinical manifestations Skin manifestations include impetigo, folliculitis, furuncle, abscess, erysipelas, cellulitis, mastitis, necrotizing fasciitis, and wound infections Bacteremia Endocarditis - Roth’s spots, Osler’s nodes, Janeway lesions, and petichiae Pericarditis Osteomyelitis – hematogenous seeding Septic Arthritis, Infected prosthetic joints Pneumonia – nosocomial pneumonia, **salmon colored sputum Toxin Mediated Diseases Staphylococcal food poisoning – Enterotoxins A-E - 2-6 hours after eating nausea, vomiting, diarrhea, and abdominal pain - Self limited Toxic Shock Syndrome TSST-1 a super antigen - Fever, erythroderma, hypotension, involvement of 3 or more organ systems, and desquamation of the palms and soles Scalded Skin Syndrome – exfoliative toxin A or B Treatment Gastroenteritis is self limiting Nafcillin/Oxacillin MRSA – Vancomycin

Answer 17

Fungus Obligate extracellular parasite Silver stain Opportunistic infection in HIV patients with CD4 count less than 200 Pneumonia: Fever, nonproductive cough, and shortness of breath X-ray with patchy infiltrate, ground glass appearance, lower lobe and periphery may be spared Diagnosis : silver staining cysts in bronchial alveolar lavage fluids or biopsy Treatment sulfamethoxazole/trimethoprim or dapsone Prevention SMX/TMP prophylaxis for CD4 counts less than 200 in HIV patients

Answer 18

Dimorphic fungus Facultative intracellular parasite – found in RES cells Found in soil, caves, and abandoned buildings with bird and bat guano Transmission - Disruption of soil; cleaning attics, bridges, and barns; tearing down old structures, and spelunking Endemic to Mississippi and Ohio River Valleys Clinical Manifestations: Acute pulmonary - Most asymptomatic - Several weeks after exposure fevers, chills, fatigue, non-productive cough, anterior chest discomfort, and myalgias Chronic pulmonary - Progressive, often fatal - Elderly, immunocompromised, and COPD patients at risk X-ray - Acute Pneumonia with patchy lobar or multilobar infiltrate - Chronic Pneumonia with upper lobe infiltrates, multiple cavities, fibrosis of lower lobes – mimics TB Treatment - Itraconazole - Amphotericin B

Answer 19

Thermally dimorphic fungus Broad based budding yeast Appears to be associated with soil and decaying vegetation, especially in areas associated with rivers and lakes. Endemic in north central, south central, great lakes, and southeastern seaboard Transmission – inhaled conidia Clinical Manifestations: - Acute Pulmonary Most asymptomatic or thought to have community acquired pneumonia Fever, malaise, nonproductive cough Chest x-ray with lobar, multilobar, or nodular infiltrates Skin lesions - Chronic Pulmonary Fever, night sweats, fatigue, weight loss, cough, hemoptysis, and dyspnea Chest x-ray with cavitary, nodular, fibrosis, mass like Treatment All patients should be treated Itraconazole in mild disease Amphotericin B in severe disease

Answer 20

Dimorphic fungi Inhaled arthroconidia enlarge and form spherules Spherules undergo internal septation producing endospores Endemic in southwest deserts Clinical Manifestations - Most asymptomatic - Pulmonary Infection: Symptoms develop 5-21 days after exposure Fever, weight loss, fatigue, dry cough, and pleuritic chest pain Arthralgias Erythema nodosum Chest x-ray with pulmonary infiltrates, hilar adenopathy, and peripneumonic effusion Pulmonary Nodule, cavitary Disseminated infection Immunocompromised , e.g. AIDS 3rd trimester pregnancy Skin, joints, and bones Treatment Itraconazole Amphotericin B

Answer 21

Thermally dimorphic fungus Endemic to humid areas of Central and South America Lives in soil Most prevalent in middle-aged to elderly men Paracoccidioidomycosis develops after inhalation of aerosolized conidia encountered in the environment - Acute-Subacute Paracoccidioidomycosis – less than 10% ----RES (reticulo-endothelial system) with dissemination to the liver, spleen, lymph nodes, and bone marrow Chronic Paracoccidioidomycosis Progressive over many years Most patients older men Pulmonary involvement mimics tuberculosis Chest x-ray with nodular, interstitial, and cavitary lesions in the middle or lower lung fields Ulcerative lesions in the anterior nares, oral cavity, and larynx that are slowly destructive Chronic Paracoccidioidomycosis Diagnosis Growth in culture Morphology Thick-walled yeast cells that have multiple small circumferentially attached, narrow-based budding daughter yeast cells Ship’s steering wheel

Answer 22

Endemic in warm climates worldwide Transmission Exposed skin comes in contact with free-living filiariform larvae living in contaminated soil. After skin penetration, larvae enter the afferent circulation and travel to the pulmonary vasculature, where they rupture into the alveolar spaces, ascend the respiratory tree, and are swallowed into the GI tract. Development into adult worms occurs in the upper part of the small intestine. Female worms begin laying eggs. Eggs hatch in the lumen of the small intestine. Rhabditiform larvae migrate to the colon and are passed in the feces. Pulmonary Manifestations Can be severe in immunocompromised Resembles ARDS with acute onset of dyspnea, productive cough, and hemoptysis accompanied by fever, tachypnea, and hypoxemia Treatment ivermectin

Answer 23

Aspergillus are ubiquitous organisms found in soil, decaying matter, and air. Spore like conidia are aerosolized from the mold form of the organism. They reach tissue and form invasive hyphae. Can be isolated from basements, crawl spaces, bedding, humidifiers, ventilation ducts, potted plants, dust, condiments, and marijuana

Answer 24

``` Immunocompromised host Fever Pulmonary infiltrates Nodules Wedge-shaped densities resembling infarcts Sinusitis Extrapulmonary sites CNS abscesses, endophthalmitis, MI, GI, renal, osteomyelitis, endocarditis ``` Diagnosis Diagnosis: BAL, needle aspiration, thoracoscopic biopsy, or open lung biopsy Treatment Antifungal- Voriconazole or liposomal amphotericin B Reversal of immunosuppression Surgical resection of infected lesions

Answer 25

Aspergilloma Ball in cavity Debris in preformed cavity from TB, Histoplamosis, or fibrocystic sarcoidosis Treatment Limited benefit with aspergilloma Antifungal – itraconazole or voriconazole in chronic cavitary pulmonary aspergillosis

Answer 26

History of chronic asthma or cystic fibrosis Airway obstruction, fever, eosinophilia, positive sputum cultures, mucous plugs containing hyphae, brown flecks in sputum, transient infiltrates, proximal bronchiectasis, upper lobe contraction, elevated IgE. Eosinophilia in blood, sputum, and lung tissue

Answer 27

``` Asthma Immediate cutaneous reaction to A. fumigatus antigen Serum IgE greater than 1000 ng/ml A. fumigatus specific serum IgE levels Precipitating serum antibodies to A. fumigatus Central bronchiectasis Peripheral eosinophilia Pulmonary infiltrates ``` Treatment Corticosteroids and itraconazole

Answer 28

Occurs most often in the immunosuppressed – HIV Meningitis is most common clinical manifestation Pulmonary and other organ involvement can occur Cryptococcus neoformans Yeast Environment and tissues Polysaccharide capsule is the major virulence factor Patients at highest risk are those with AIDS and CD4 counts less than 50. Inhaled from the environment and causes pulmonary infection initially. Most patient asymptomatic. If the host becomes immunosuppressed the organism can reactivate and disseminate to other sites. C. neoformans is neurotropic ``` Central Nervous System Infection: Meningoencephalitis Headaches over several weeks Nuchal rigidity Lethargy Personality changes Confusion Visual abnormalities Nausea and vomiting ``` Pulmonary Infection Risk factors include COPD, Corticosteroid use, and solid organ transplant Fever, cough, and dyspnea Treated with antifungals Other organs affected Skin, prostate, osteoarticular surfaces, breast, eye, and larynx. Diagnosis Yeast is grown in culture from CSF, Blood, sputum, skin lesions, or other body fluids India Ink stain – visualization of budding yeast with large capsule Latex agglutination for Cryptococcal polysaccharide antigen Treatment of CNS infection Non-AIDS Patients Amphotericin B and flucytosine for 6 weeks AIDS Patients Amphotericin B and flucytosine for 2 weeks, followed by fluconazole 400 mg daily for 8 weeks, then suppressive therapy with fluconazole 200 mg daily

Answer 29

``` Haemophilus spp Actinobacillus actinomycetemcomitans Cardiobacterium hominis Eikenella corrodens Kingella spp 5% of endocarditis cases Normal flora Common Cause of endocarditis in non-IV drug users Difficult to diagnose- often takes 3 months ```

Answer 30

H. influenzae Chocolate Agar with Factors V(NAD+) and X(Hematin) N. meningitidis Thayer-Martin B. pertussis Bordet-Gengou C. diphtheriae Loffler medium M. pneumoniae Eaton Agar – requires cholesterol Legionella Charcoal Yeast Extract cysteine and iron

Answer 31

Chlamydia Giemsa Cryptococcus India Ink Pneumocystis Silver Stain Mycobacteria Ziehl-Neelsen