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1

Streptococcal Pharyngitis (Strep Throat) (56)

Signs & Symptoms
Sore throat, difficulty swallowing, laryngitis if infection spreads to lower respiratory tract; may progress to scarlet fever or pneumonia; acute glomeronephritis occurs in some untreated cases

Pathogen & Virulence factors
Caused by GROUP A STREPTOCOCCI (STREPTOCOCCUS PYOGENES); has variety of virulence factors

Pathogenesis:
occurs when normal microbiota are depleted, large inoculum is introduced, or adaptive immunity is impaired

Epidemiology
Spread via respiratory droplets; occurs most often in winter and spring

Diagnosis, treatment, and prevention
Often confused with viral pharyngitis, oral penicillin is an effective treatment

2

Diphtheria (57)

Signs & Symptoms
Sore throat, localized pain, fever; presence of PSEUDOMEMBRANE that can obstruct airways

Pathogen & Virulence Factors
Caused by CORYNEBACTERIUM DIPHTHERIAE; PRODUCES DIPHTHERIA TOXIN; prevents polypeptide synthesis and causes cell death

Pathogenesis and Epidemiology
Spread via respiratory droplets or skin contact; symptomatic in immunocompromised or nonimmune individuals; LEADING CAUSE OF DEATH AMONG UNIMMUNIZED CHILDREN

Diagnosis, treatment, prevention
Diagnosis is based on presence of pseudomembrane; treated with antitoxin and antibiotics; immunization available

3

Common Cold (58)

Signs & Symptoms
Sneezing, runny nose, congestion, sore throat, malaise, and cough

Pathogens and Virulence Factors
Enterovirus (RHINOVIRUS) are the most common cause; numerous other viruses cause colds; cold viruses replicate at the lower temperature of the nasal cavity

Pathogenesis
Cold viruses replicate in and kill infected cells

Epidemiology
Rhinoviruses are highly virulent; spread through coughing sneezing, fomites, or person to person contact; develop some immunity to serotypes over time

Diagnosis, treatment, and prevention
Signs and symptoms are usually diagnostic; pleconaril can reduce duration of symptoms; hand antisepsis is important preventative measure

4

Pneumococcal Pneumonia (59)

Signs & Symptoms
Fevers, chills, congestion, cough, chest pain; results in short rapid breathing, blood enters lungs, causing rust colored sputum

Pathogen & Virulence Factors
Caused by STREPTOCOCCUS PNEUMONIAE
Adhesions, Capsure, and pneumolysin are virulence factors

Pathogenesis and Epidemiology
PNEUMOCOCCAL PNEUMONIA ACCOUNT FOR MOST CASES OF BACTERIAL PNEUMONIA; infection occurs by inhalation of bacteria; bacterial replication causes damage to lungs

Diagnosis, treatment, and prevention
Diagnosed by identifying diplococci in sputum smears; penicillin is drug of choice for treatment; some strains are penicillin resistant; vaccination is avaiable

5

Primary Atypical (Mycoplasmal) Pneumonia (60)

Signs & Symptoms
Include Fever, malaise, sore throat, excessive sweating; SYMPTOMS MAY LAST FOR WEEKS, MORE MILD-'WALKING PNEUMONIA"

Pathogen and Virulence Factors
Caused by MYCOPLASMA PNEUMONIAE; virulence factors include adhesion proteins

Pathogenesis
Bacteria colonize and kill epithelial cells; causes mucus buildup and colonization by other bacteria

Epidemiology
Bacteria spread by nasal secretions; most common form of pneumonia in teenagers and young adults *

Diagnosis, treatment, Prevention
Difficult to diagnose, treated w/erythromycin and doxyclycline; prevention difficult because infected individuals may be asymptomatic

6

Klebsiella Pneumonia (61)

Signs & Symptoms
PNEUMONIA SYMPTOMS WITH A THICK, BLOODY SPUTUM

Pathogen and virulence factors
Caused by KLEBSIELLA PNEUMONIAE; virulence factors include a capsule

Pathogenesis and Epidemiology
Immunocompromised individuals at greatest risk for infection

Diagnosis, treatment, prevention
Diagnosed by identifying klebsiella in sputum; treated with antimicrobials, prevention involves good aseptic technique by health care workers

7

Legionnaire's Disease (64) (Bacteria)

Signs & Symptoms
Typical pneumonia symptoms; pulmonary function may decrease rapidly

Pathogen and Virulence factors
Caused by LEGIONALLA PNEUMOPHILA

Pathogenesis
L PNEUMOPHILA KILLS HUMAN CELLS; CAUSES TISSUE DAMAGE AND INFLAMMATION

Epidemiology
Legionella survives in domestic water sources, elderly, smoker, and immunocompromised at risk

Diagnosis, treatment, prevention
Diagnosed with florescent antibody staining or serology; quinolones or macrolides are preferred treatement; controlled by reducing bacterial presence in water

8

Tuberculosis (65) (Bacteria)

LEADING DISEASE KILLER IN THE WORLD

Signs & Symptoms
Initially limited to minor cough and mild fever; not always apparent

Pathogen & Virulence Factors
Caused by MYCOBACTERIUM TUBERCULOSIS; presence of MYCOLIC ACID gives unique features; SLOW GROWTH; PROTECTION FROM PHAGOCYTIC LYSIS; INTRACELLULAR GROWTH, RESISTANCE TO MANY ANTIMICROBIAL DRUGS

Pathogenesis
Spread via inhalation of respiratory drops; 3 types (Primary, Secondary, Disseminated tuberculosis)

Epidemiology
1/3 of worlds population is infected; most deaths occur in Asia/Africa

Diagnosis, treatment, prevention
Tuberculin skin test identifies exposed tuberculosis; chest x-ray, treatment is combination of drugs; drug resistant strains have emerged; BCG vaccine is available

9

Pertussis (Whooping Cough) (66)

Signs & Symtoms
Initially coldlike, then characteristic cough develops

Pathogen and Virulence factors
BORDETELLA PERTUSSIS is causative agent; includes adhesions and SEVERAL TOXINS

Pathogenesis
4 phases of progression; Incubation, catarrhal, paroxysmal, and convalescent

Epidimiology
Highly contagious; Bacteria spread through airborne droplets in air, bacteria does not survive long outside of body

Diagnosis, treatment, prevention
Symptoms are usually diagnostic; treatment is mainly supportive, DTaP vaccine

10

Inhalational Anthrax (67) Bacterial

Signs & Symptoms
Initially resembles a cold or flu; progresses to severe coughing, lethargy, shock, and death

Pathogen and Virulence Factors
BACILLUS ANTHRACIS ; virulence factors include a capsule and ANTHRAX TOXIN

Pathogenesis and Epidemiology
Anthrax is not spread from person to person; acquired by contact or inhalation of endospore

Diagnosis, treatment, and prevention
Diagnosis based on identification of bacteria in sputum, early and aggressive antimicrobial treatment is necessary; anthrax vaccine is available to select individuals

11

Influenza (68) viral

Signs & Symptoms
Pharyngitis, congestion, cough, myalgia; sudden fever distinguishes flu from common cold

Pathogens and Virulence Factors
INFLUENZA VIRUS TYPE A AND B; mutations in HEMAGGLUTININ AND NEURAMINIDASE PRODUCE NEW STRAINS; occurs via antigenic drift and antigenic drift
Concern about the fatality associated w/strains similiar to those of past pandemics

Pathogenesis
Symptoms produced by immune response to virus; flu patients are susceptible to secondary bacterial infections; cause damage to lung epithelium

Epidemiology
Transmitted via inhalation of viruses or by self-inoculation; complication occur in those with weak immune systems

12

Respiratory Syncytial Virus Infection (69)

MOST COMMON CHILDHOOD RESPIRATORY DISEASE

Signs & Symptoms
Fever, runny nose, coughing in babies or immunocompromised; mild coldlike symptoms in children and adults

Pathogen
RESPIRATORY SYNCYTIAL VIRUS (RSV)

Pathogenesis
Virus causes SYNCYTIA to form the lungs; immune response to RSV further damages lungs

Epidimiology
Transmission occurs via close contact with infected persons

Diagnosis, treatment, prevention
Diagnosis made my immunoassay; supportive treatment for young; prevention includes aseptic technique of health care workers and day care employees

13

Hantavirus Pulmonary Syndrome (HPS) (70)

Signs & Symptoms
Symptoms progress to cough, shock, and labored breathing

Pathogen
Caused by HANTAVIRUS; transmitted from mice via inhalation

Pathogenesis
Hantavirus travels throughout the body via the blood; infection causes widespread inflammation leading to shock

Epidemiology
Human disease more likely as mouse population increases; person to person contact does not occur

Diagnosis, treatment, and prevention
Diagnosis is based on characteristic symptoms; no pharmaceutical treatment available, prevention is control of rodents

14

Coccidiodomycosis (71)

Signs & Symptoms
Resembles pneumonia or tuberculosis; can become systemic in immunocompromised patients

Pathogen and Virulence Factors
Caused by COCCIDIOIDES IMMITIS; pathogen assumes yeast form at human body temperature

Pathogenesis
Arthroconidia from soil enter the body through inhalation

Epidemiology
ALMOST EXCLUSIVELY IN SOUTHWESTERN US & NORTHERN MEXICO

Diagnosis, treatment, prevention
Diagnosed by presence of spherules in clinical specimens; treated with amphotericin B; protective masks can prevent exposure

15

Blastomycosis (72)

Signs & Symptoms
Flu like; Systemic infections can PRODUCE LESIONS ON THE FACE AND UPPER BODY or purulent lesions on various organs

Pathogen
BLASTOMYCES DERMATIDITIS; pathogen yeast from at human body temperature

Pathogenesis & Epidemiology
Enters body through inhalation of dust carrying fungal spores; incidence of human infection is increasing

Diagnosis, treatment, and prevention
Identify fungus in samples; treated with amphotericin B; relapse common in aids patients

16

Histoplasmosis (73)

Signs & Symptoms
Asymptomatic in most cases; symptomatic infection causes coughing with bloody sputum or skin lesions

Pathogen
HISTOPLASMA CAPSULATUM; pathogenic yeast form at human body temp.; histoplasma produces several proteins that inhibit macrophage activities and other hose defenses

Pathogenesis and epidemiology
Humans inhale airborne SPORES FROM THE SOIL (FORM BIRD OR BAT DROPPINGS); PREVALENT IN THE EASTERN US

Diagnosis, treatment, and prevention
Diagnosis is based on identifying fungus, in clinical samples; infections in immunocompromised usually resove without treatment

17

Pneumocystis Pneumonia (PCP) (74)

Signs & Symptoms
Difficulty breathing, anemia, hypoxia, fever

Pathogen
PNEUMOCYSTIS JIROVECII

Pathogenesis and Epidemiology
COMMON DISEASE IN AIDS PATIENTS; transmitted by inhalation of droplets containing the fungus

Diagnosis, treatment, and prevention
Diagnosis based on clinical microscopic findings; treated with trimethoprim and sulfamethoxazole; impossible to prevent infection with P jirovecii