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BMS 250 test 2 > Week 6 Lecture 3 > Flashcards

Week 6 Lecture 3 Flashcards

1
Q
A
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2
Q

Who developed the staining method for classifying bacteria?

A

Hans Christian Gram

Developed the Gram staining method in 1884 using crystal violet dye.

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3
Q

What color do Gram-positive bacteria stain?

A

BLUE

Due to the retention of crystal violet dye by the thick peptidoglycan cell wall.

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4
Q

What color do Gram-negative bacteria stain?

A

RED

Caused by a different cell wall structure that does not retain the crystal violet dye.

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5
Q

What is the main distinction between aerobic and anaerobic bacteria?

A

Aerobic bacteria need oxygen for growth, whereas anaerobic bacteria have difficulties growing in the presence of oxygen.

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6
Q

What are the three main morphologies of bacteria?

A
  • Spherical (cocci)
  • Cylindric (bacilli)
  • Spiral (spirochetes)
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7
Q

Name two important human pathogens that are Gram-positive cocci.

A
  • Staphylococcus aureus
  • Streptococcus pyogenes
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8
Q

How do staphylococci and streptococci differ microscopically?

A

Staphylococci appear in grapelike clusters, while streptococci appear in chains.

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9
Q

What biochemical property differentiates staphylococci from streptococci?

A

Staphylococci produce catalase, whereas streptococci do not.

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10
Q

What are the three species of Staphylococcus mentioned?

A
  • S. aureus
  • S. epidermidis
  • S. saprophyticus
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11
Q

Where is the main site of colonization for Staphylococcus aureus?

A

The nose

Approximately 30% of people are colonized at any one time.

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12
Q

What are the three exotoxins produced by Staphylococcus aureus?

A
  • Enterotoxin
  • Toxic Shock Syndrome Toxin
  • Exfoliatin
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13
Q

What type of inflammation does Staphylococcus aureus induce?

A

Pyogenic (pus-producing) inflammation.

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14
Q

What is the leading bacterial cause of pharyngitis?

A

S. pyogenes (Group A Streptococcus)

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15
Q

What type of hemolytic streptococci produce a clear zone around their colonies?

A

β-Hemolytic streptococci

This occurs due to complete lysis of red blood cells.

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16
Q

What is the primary cause of neonatal sepsis and meningitis?

A

S. agalactiae (Group B Streptococcus)

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17
Q

What are the main infections caused by Streptococcus pneumoniae?

A
  • Pneumonia
  • Bacteremia
  • Meningitis
  • Infections of the upper respiratory tract
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18
Q

What is a key virulence factor of Streptococcus pneumoniae?

A

Polysaccharide capsules that interfere with phagocytosis.

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19
Q

What is the primary mode of transmission for pneumococci?

A

Humans are the natural hosts, with 5%–50% of the healthy population carrying them in the oropharynx.

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20
Q

What is the primary cause of atypical pneumonia?

A

Organisms such as Mycoplasma pneumoniae, Chlamydia trachomatis, and Legionella.

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21
Q

What defines community-acquired pneumonia (CAP)?

A

Pneumonia acquired outside of a hospital setting.

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22
Q

What are the two categories of nosocomial pneumonia?

A
  • Hospital-acquired pneumonia (HAP)
  • Ventilator-associated pneumonia (VAP)
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23
Q

What are the first line defenses in innate immunity for the respiratory system?

A
  • Intact respiratory epithelium
  • Cough reflex
  • Mucus & mucociliary clearance
  • Immunoglobulin A
  • Cytokines
  • Splenic function
  • Complement
  • Neutrophils
  • Macrophages
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24
Q

What increases the risk of pneumococcal infection in infants?

A

Poorly developed B-cell responses in children under 1-2 years old.

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25
Q

What are common risk factors for typical community-acquired pneumonia?

A

Defects in normal defense mechanisms or overwhelming virulent pathogens.

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26
Q

What is a significant characteristic of Pseudomonas aeruginosa?

A

Can cause localized and systemic illness in virtually any tissue or organ.

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27
Q

What is the primary cause of subacute bacterial endocarditis?

A

S. viridans.

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28
Q

What are the two types of diseases caused by S. pyogenes?

A
  • Pyogenic diseases
  • Toxigenic diseases
  • Immunologic diseases
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29
Q

What is the primary role of IgA protease in S. pneumoniae?

A

Enhances the organism’s ability to colonize the mucosa of the upper respiratory tract by cleaving IgA.

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30
Q

True or False: All streptococci are catalase positive.

A

False

All streptococci are catalase negative.

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31
Q

What are the two main risk factors for pneumonia?

A

A) defect in normal defense mechanisms B) large infectious inoculum or virulent pathogen

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32
Q

What are the risk factors for infection by common pathogens in typical CAP?

A

Risk factors include age, comorbidities, and smoking.

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33
Q

What are the most common bacterial pathogens in CAP?

A
  • Streptococcus pneumoniae
  • Haemophilus influenzae
  • Staphylococcus aureus
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34
Q

What are the most common viral causes of CAP?

A
  • coronaviruses (SARS-CoV-2, MERS)
  • influenza virus
  • respiratory syncytial virus
  • Adenovirus
  • Parainfluenza virus
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35
Q

Name two uncommon pathogens associated with pneumonia.

A
  • Chlamydophila psittaci
  • Coxiella burnetii
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36
Q

What are the three widely available diagnostic tests for CAP?

A
  • Sputum Gram stain and culture
  • Urinary antigen tests for S. pneumoniae and Legionella species
  • Tests for viruses such as influenza and SARS-CoV-2
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37
Q

List clinical findings indicative of CAP.

A
  • Fever (>38°C)
  • Leukopenia (<4000 WBC/mm3) or leukocytosis (≥12,000 WBC/mm3)
  • Altered mental status in adults ≥70 years
  • New onset of purulent sputum
  • Worsening gas exchange
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38
Q

What characterizes typical pneumonia on an X-Ray?

A

X-Ray corresponds with clinical findings on physical examination.

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39
Q

Define lobar pneumonia.

A

Acute exudative inflammation of an entire lobe with uniform consolidation.

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40
Q

What are the updated recommendations for pneumococcal vaccines in adults over 65?

A
  • 20-valent pneumococcal conjugate vaccine (PCV20)
  • Sequential administration of PCV15 and PPSV23
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41
Q

What is the transmission method for Mycoplasma pneumoniae?

A

Transmitted by respiratory droplets.

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42
Q

True or False: Chlamydia pneumoniae has a seasonal incidence.

A

False

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43
Q

What are the distinguishing features of nosocomial pneumonia?

A
  • Different infectious causes
  • Different antibiotic susceptibility patterns
  • Poorer underlying health status of patients
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44
Q

What is the most common cause of hospital-acquired pneumonia (HAP)?

A

Streptococcus species.

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45
Q

What factors increase the risk for hospital-acquired pneumonia?

A
  • Instrumentation of the upper airway
  • Contact with contaminated aerosols
  • Treatment with broad-spectrum antibiotics
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46
Q

What characterizes ventilator-associated pneumonia (VAP)?

A

New pneumonia developing > 48 hours following endotracheal intubation.

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47
Q

What is the microbiology of early hospital-acquired pneumonia?

A
  • Enteric gram-negative bacilli
  • Haemophilus influenzae
  • Staphylococcus aureus
  • Streptococcus pneumoniae
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48
Q

What is a lung abscess?

A

A necrotizing lung infection characterized by a pus-filled cavitary lesion.

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49
Q

What are common causes of lung abscesses?

A
  • Aspiration of oral secretions
  • Endobronchial obstruction
  • Hematogenous seeding
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50
Q

What is the most common microbiological cause of lung abscess?

A

Anaerobic bacteria.

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51
Q

What is the primary clinical picture of a lung abscess?

A
  • Productive cough
  • Fever
  • Weight loss
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52
Q

What is the definition of tuberculosis?

A

One of the oldest diseases affecting humans, caused by Mycobacterium tuberculosis.

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53
Q

What is the transmission method for Mycobacterium tuberculosis?

A

Aerosolized droplet nuclei from an infected person.

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54
Q

What are risk factors for active tuberculosis?

A
  • Crowding in poorly ventilated rooms
  • Immunocompromised status
  • Endogenous factors like innate immunologic defenses
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55
Q

What does the Tuberculin test indicate?

A

Induration of more than 15 mm indicates active infection.

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56
Q

What is the role of BCG vaccination?

A

Primovaccination of healthy newborns and revaccination of tuberculin-negative children.

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57
Q

Who developed the staining method using crystal violet dye?

A

Hans Christian Gram

The staining method was developed in 1884.

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58
Q

What color do Gram-positive bacteria stain?

A

BLUE

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59
Q

What color do Gram-negative bacteria stain?

A

RED

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60
Q

Why do Gram-negative and Gram-positive bacteria stain differently?

A

Their cell walls are different

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61
Q

What are the two classifications of bacteria based on oxygen requirements?

A

Aerobic and Anaerobic

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62
Q

What do aerobic bacteria need for growth?

A

Oxygen

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63
Q

What difficulties do anaerobic bacteria face?

A

Difficulties to grow when oxygen is present

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64
Q

Where is a large part of the normal resident flora located?

A

Mucous membranes: mouth, lower gastrointestinal tract, and vagina

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65
Q

What can cause disease when mucous membranes are disrupted?

A

Anaerobes from normal flora

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66
Q

What are the three morphological classifications of bacteria?

A

Spherical (cocci), Cylindric (bacilli), Spiral (spirochetes)

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67
Q

Name two important human pathogens that are Gram-positive cocci.

A

Staphylococcus aureus and Streptococcus pyogenes

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68
Q

How do staphylococci appear microscopically?

A

In grapelike clusters

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69
Q

How do streptococci appear microscopically?

A

In chains

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70
Q

What biochemical property differentiates staphylococci from streptococci?

A

Staphylococci produce catalase; streptococci do not

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71
Q

What is the arrangement of Staphylococcus aureus?

A

Spherical gram-positive cocci in irregular grapelike clusters

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72
Q

What important virulence factor does Staphylococcus aureus produce?

A

Catalase

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73
Q

List three species of Staphylococcus.

A
  • S. aureus
  • S. epidermidis
  • S. saprophyticus
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74
Q

What primarily distinguishes S. aureus from other Staphylococcus species?

A

Coagulase production

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75
Q

What is a significant characteristic of S. aureus in terms of antibiotic resistance?

A

Production of beta-lactamase

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76
Q

Where is the main site of colonization for S. aureus?

A

The nose

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77
Q

What percentage of people are approximately colonized by S. aureus at any one time?

A

30%

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78
Q

What is an important mode of transmission for S. aureus?

A

Hand contact

79
Q

What can decrease transmission of S. aureus?

A

Handwashing

80
Q

Name one of the three exotoxins produced by S. aureus.

A

Enterotoxin, Toxic Shock Syndrome Toxin, or Exfoliatin

81
Q

What does enterotoxin cause?

A

Food poisoning

82
Q

In which individuals can Toxic Shock Syndrome Toxin cause toxic shock?

A

In tampon-using menstruating women, individuals with wound infections, patients with nasal packing

83
Q

What condition does Exfoliatin cause in young children?

A

Scalded-skin syndrome

84
Q

What localized production of S. aureus results in bullous impetigo?

A

Exfoliatin

85
Q

What type of inflammation is induced by S. aureus?

A

Pyogenic (pus-producing) inflammation.

S. aureus causes disease through toxins and pyogenic inflammation.

86
Q

List three typical lesions caused by S. aureus.

A
  • Abscess
  • Folliculitis
  • Impetigo
87
Q

What are predisposing factors to infection by S. aureus?

A
  • Foreign bodies
  • Sutures
  • Intravenous catheters
88
Q

What type of bacteria are streptococci?

A

Spherical gram-positive cocci arranged in chains or pairs.

All streptococci are catalase negative.

89
Q

How are streptococci classified?

A

Into groups A–U (Lancefield groups) based on antigenic differences in C carbohydrate.

90
Q

What is the most important human pathogen among Group A streptococci?

A

S. pyogenes.

91
Q

What is the leading bacterial cause of pharyngitis?

A

S. pyogenes.

92
Q

Define α-hemolytic streptococci.

A

Streptococci that produce a green zone around their colonies due to incomplete lysis of red blood cells.

93
Q

Define β-hemolytic streptococci.

A

Streptococci that produce a clear zone around their colonies due to complete lysis of red blood cells.

94
Q

What causes β-hemolysis in streptococci?

A

The production of enzymes (hemolysins) called streptolysin O and streptolysin S.

95
Q

What is the main transmission route for streptococci?

A

Most are part of the normal flora of the human throat, skin, and intestines.

96
Q

Where is S. pyogenes typically found in the body?

A

On the skin and in the oropharynx in small numbers.

97
Q

Which streptococcus is known for causing neonatal sepsis and meningitis?

A

S. agalactiae (Group B Streptococcus).

98
Q

What are the three types of diseases caused by S. pyogenes?

A
  • Pyogenic diseases
  • Toxigenic diseases
  • Immunologic diseases
99
Q

What is a common cause of subacute bacterial endocarditis?

A

S. viridans.

100
Q

What types of infections is Streptococcus pneumoniae associated with?

A
  • Pneumonia
  • Bacteremia
  • Meningitis
  • Upper respiratory tract infections (otitis media, mastoiditis, sinusitis)
101
Q

What is the significance of pneumococci in community-acquired pneumonia?

A

They are the most common cause.

102
Q

What does the name ‘Streptococcus’ derive from?

A

From the Greek words ‘streptos’ meaning ‘twisted’ and ‘kokkos’ meaning ‘berry’.

103
Q

Fill in the blank: α-hemolytic streptococci produce a _______ color on blood agar.

104
Q

What molecules have been identified within the pneumococcal cell that may play a role in pathogenesis and virulence?

A

Many molecules within the cytoplasm, cell membrane, and cell wall

These include key antigens and factors contributing to virulence.

105
Q

What role do polysaccharide capsules play in S. pneumoniae pathogenesis?

A

Interfere with phagocytosis

Polysaccharide capsules are a key virulence factor.

106
Q

What is C-reactive protein (CRP)?

A

An ‘acute-phase’ protein that is elevated in acute inflammation

CRP is not an antibody but rather a β-globulin.

107
Q

How much can CRP be elevated during acute inflammation?

A

Up to 1000-fold

This elevation is a nonspecific indicator of inflammation.

108
Q

What is a key characteristic that distinguishes CRP from antibodies?

A

CRP is a β-globulin, while antibodies are γ-globulins

This distinction is important in understanding immune responses.

109
Q

What does elevated CRP indicate in clinical practice?

A

A better predictor of heart attack risk than elevated cholesterol levels

This highlights the clinical significance of CRP measurement.

110
Q

What is pneumolysin?

A

A hemolysin that causes α-hemolysis and may contribute to pathogenesis

Pneumolysin is another virulence factor of S. pneumoniae.

111
Q

What is the function of IgA protease produced by pneumococci?

A

Enhances the organism’s ability to colonize the mucosa by cleaving IgA

This helps pneumococci evade the immune response.

112
Q

What happens when pneumococci reach the alveoli?

A

Outpouring of fluid and red and white blood cells, resulting in lung consolidation

This is part of the inflammatory response to infection.

113
Q

What occurs during recovery from pneumococcal infection?

A

Pneumococci are phagocytized, mononuclear cells ingest debris, and consolidation resolves

This process is crucial for healing.

114
Q

What is the natural host for pneumococci?

A

Humans

There is no animal reservoir for pneumococci.

115
Q

What percentage of the healthy population can carry pneumococci in the oropharynx?

A

5%–50%

This indicates the prevalence of asymptomatic carriers.

116
Q

What are some predisposing factors for pneumococcal disease?

A

1) Alcohol or drug intoxication
2) Abnormality of the respiratory tract
3) Abnormal circulatory dynamics
4) Splenectomy
5) Certain chronic diseases

These factors increase the risk of developing disease.

117
Q

Name two Gram-negative bacteria associated with respiratory infections.

A

1) Haemophilus influenzae
2) Klebsiella pneumoniae

These bacteria are significant pathogens in respiratory disease.

118
Q

What type of infections does Haemophilus influenzae typically cause?

A

Normal component of the upper respiratory tract flora

It can cause various infections when it overgrows or enters sterile areas.

119
Q

What is Bordetella pertussis known for causing?

A

Pertussis (whooping cough)

It is an important cause of morbidity and mortality worldwide.

120
Q

What is a significant effect of pertussis vaccines?

A

Lowering the incidence of whooping cough

Vaccination has significantly impacted public health.

121
Q

What types of illnesses can Pseudomonas aeruginosa cause?

A

Localized and systemic illness affecting virtually any tissue or organ

It is particularly problematic in immunocompromised individuals.

122
Q

In what conditions is Klebsiella pneumoniae particularly dangerous?

A

Necrotizing lobar pneumonia in individuals compromised by alcoholism, diabetes, or COPD

It is associated with severe infections in at-risk populations.

123
Q

What type of organism is Klebsiella pneumoniae?

A

Large, nonmotile bacilli that produce an abundant capsule

This capsule contributes to its virulence.

124
Q

What are the bacteria causing atypical pneumonia?

A

Legionella, Mycoplasma pneumoniae, Chlamydia trachomatis

These bacteria are known for causing atypical presentations of pneumonia.

125
Q

What is Legionnaires disease?

A

An atypical, acute lobar pneumonia with multisystem symptoms that can occur sporadically or in outbreaks

It is often associated with the inhalation of contaminated aerosols or aspiration of water containing Legionella.

126
Q

What are the two main categories of pneumonia?

A
  1. Community-acquired pneumonia (CAP)
  2. Nosocomial pneumonia

Nosocomial pneumonia includes hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).

127
Q

What are the types of community-acquired pneumonia (CAP)?

A
  1. Typical CAP (S. pneumoniae)
  2. Atypical CAP (Mycoplasma, Chlamydia, Legionella)

These types are differentiated by the causative organisms.

128
Q

What are the first line of defense mechanisms in innate immunity for respiratory infections?

A
  1. Intact respiratory epithelium; cough reflex
  2. Nonspecific or innate immune factors

These factors include mucus, immunoglobulin A, cytokines, splenic function, complement, neutrophils, and macrophages.

129
Q

What is acquired immunity in the context of pneumonia?

A

Induced following colonization or exposure to cross-reactive antigens leading to the development of serum IgG antibodies

This immunity is crucial for responding to pneumococcal infections.

130
Q

What is the risk associated with infants and agammaglobulinemia regarding pneumonia?

A

High risk of pneumococcal infection due to poorly developed B-cell responses

Agammaglobulinemia results in the absence of serum immunoglobulin, increasing susceptibility.

131
Q

What are the conditions that increase the risk of pneumonia?

A

A) Defect in normal defense mechanisms
B) Large infectious inoculum or virulent pathogen

These conditions can overwhelm the immune response.

132
Q

What are the most common viral causes of community-acquired pneumonia (CAP)?

A

coronaviruses (SARS-CoV-2, MERS), influenza virus, respiratory syncytial virus, adenovirus, parainfluenza virus

These viruses are frequently implicated in CAP.

133
Q

Fill in the blank: Atypical pneumonia can be caused by _______.

A

Mycoplasma pneumoniae, Chlamydia trachomatis, Legionella

These pathogens lead to atypical presentations of pneumonia.

134
Q

True or False: Typical CAP is primarily associated with Streptococcus pneumoniae.

A

True

S. pneumoniae is the most common bacterial cause of typical community-acquired pneumonia.

135
Q

What are uncommon pathogens that can cause pneumonia?

A

Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, Blastomyces, Coccidioides, Histoplasma, Sin Nombre virus

These pathogens are less frequently associated with pneumonia but can cause significant disease.

136
Q

What are the bacteria causing atypical pneumonia?

A

Legionella, Mycoplasma pneumoniae, Chlamydia trachomatis

These bacteria are known for causing atypical presentations of pneumonia.

137
Q

What is Legionnaires disease?

A

An atypical, acute lobar pneumonia with multisystem symptoms that can occur sporadically or in outbreaks

It is often associated with the inhalation of contaminated aerosols or aspiration of water containing Legionella.

138
Q

What are the two main categories of pneumonia?

A
  1. Community-acquired pneumonia (CAP)
  2. Nosocomial pneumonia

Nosocomial pneumonia includes hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).

139
Q

What are the types of community-acquired pneumonia (CAP)?

A
  1. Typical CAP (S. pneumoniae)
  2. Atypical CAP (Mycoplasma, Chlamydia, Legionella)

These types are differentiated by the causative organisms.

140
Q

What are the first line of defense mechanisms in innate immunity for respiratory infections?

A
  1. Intact respiratory epithelium; cough reflex
  2. Nonspecific or innate immune factors

These factors include mucus, immunoglobulin A, cytokines, splenic function, complement, neutrophils, and macrophages.

141
Q

What is acquired immunity in the context of pneumonia?

A

Induced following colonization or exposure to cross-reactive antigens leading to the development of serum IgG antibodies

This immunity is crucial for responding to pneumococcal infections.

142
Q

What is the risk associated with infants and agammaglobulinemia regarding pneumonia?

A

High risk of pneumococcal infection due to poorly developed B-cell responses

Agammaglobulinemia results in the absence of serum immunoglobulin, increasing susceptibility.

143
Q

What are the conditions that increase the risk of pneumonia?

A

A) Defect in normal defense mechanisms
B) Large infectious inoculum or virulent pathogen

These conditions can overwhelm the immune response.

144
Q

What are the most common viral causes of community-acquired pneumonia (CAP)?

A

coronaviruses (SARS-CoV-2, MERS), influenza virus, respiratory syncytial virus, adenovirus, parainfluenza virus

These viruses are frequently implicated in CAP.

145
Q

Fill in the blank: Atypical pneumonia can be caused by _______.

A

Mycoplasma pneumoniae, Chlamydia trachomatis, Legionella

These pathogens lead to atypical presentations of pneumonia.

146
Q

True or False: Typical CAP is primarily associated with Streptococcus pneumoniae.

A

True

S. pneumoniae is the most common bacterial cause of typical community-acquired pneumonia.

147
Q

What are uncommon pathogens that can cause pneumonia?

A

Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, Blastomyces, Coccidioides, Histoplasma, Sin Nombre virus

These pathogens are less frequently associated with pneumonia but can cause significant disease.

148
Q

What is the purpose of diagnostic testing in CAP?

A

To adjust empirically chosen therapy and facilitate epidemiologic analysis.

149
Q

Name three widely available diagnostic tests for CAP.

A
  • Sputum Gram stain and culture
  • Urinary antigen tests for S. pneumoniae and Legionella species
  • Tests for viruses such as influenza and SARS-CoV-2
150
Q

What is the typical fever threshold in CAP?

151
Q

What leukocyte counts are associated with CAP?

A
  • Leukopenia: <4000 WBC/mm3
  • Leukocytosis: ≥12,000 WBC/mm3
152
Q

What altered mental status is significant in adults ≥70 years in CAP?

A

Altered mental status without an alternative etiology.

153
Q

What are common symptoms indicating CAP?

A
  • New onset of purulent sputum
  • Change in character of sputum
  • Increased secretions/suction requirements
  • New-onset or worsening cough
  • Dyspnea
  • Tachypnea
  • Rales or bronchial breath sounds
  • Worsening gas exchange
154
Q

What characterizes Typical CAP on an X-ray?

A

The X-Ray corresponds with clinical findings on physical examination.

155
Q

Define lobar pneumonia.

A

Acute exudative inflammation of the entire lobe with uniform consolidation.

156
Q

What is the most common cause of lobar pneumonia?

A

Streptococcus pneumoniae.

157
Q

How does bronchopneumonia differ from lobar pneumonia?

A

Bronchopneumonia inflames the alveoli with incomplete consolidation within lung regions.

158
Q

What are the updated recommendations for the pneumococcal vaccine?

A
  • 20-valent pneumococcal conjugate vaccine (PCV20) alone
  • Sequential administration of 15-valent PCV (PCV15) and 23-valent polysaccharide vaccine (PPSV23)
159
Q

In which populations is the pneumococcal vaccine recommended?

A
  • All adults aged 65 years or older
  • Adults with comorbidities (chronic lung disease, liver disease, diabetes)
  • Increased risk of meningitis, asplenia, or immunocompromise.
160
Q

What characterizes atypical pneumonia?

A

The X-Ray does not correspond with clinical findings on physical examination.

161
Q

How is Mycoplasma pneumoniae transmitted?

A

By respiratory droplets.

162
Q

What percentage of pneumonia cases are attributed to Mycoplasma pneumoniae?

163
Q

What age group has the highest incidence of Mycoplasma pneumoniae clinical disease?

A

Older children and young adults (ages 5-20 years).

164
Q

What is a significant respiratory pathogen causing pharyngitis and atypical pneumonia?

A

Chlamydia pneumoniae.

165
Q

What is Legionnaires disease?

A

An atypical, acute lobar pneumonia with multisystem symptoms.

166
Q

What distinguishes community-acquired pneumonia from nosocomial pneumonia?

A
  • Different infectious causes
  • Different antibiotic susceptibility patterns
  • Poorer underlying health status of patients.
167
Q

What is the definition of hospital-acquired pneumonia (HAP)?

A

Clinical features and imaging consistent with pneumonia occurring > 48 hours after hospital admission.

168
Q

What is the definition of ventilator-associated pneumonia (VAP)?

A

New pneumonia developing > 48 hours following endotracheal intubation and mechanical ventilation.

169
Q

List some exogenous risk factors for HAP.

A
  • Instrumentation of the upper airway
  • Contact with personnel and equipment
  • Treatment with broad-spectrum antibiotics.
170
Q

What are some patient factors that increase the risk for HAP?

A
  • Malnutrition
  • Advanced age
  • Altered consciousness
  • Swallowing disorders
  • Underlying pulmonary and systemic diseases.
171
Q

What microbiological agents are common in HAP?

A
  • S aureus (including MRSA)
  • Streptococcus species
  • P aeruginosa
  • Other gram-negative rods.
172
Q

What is the etiology of early HAP?

A
  • Enteric GNB (E coli, K pneumoniae, Proteus, Serratia)
  • H influenzae
  • S aureus
  • S pneumoniae.
173
Q

What organisms are more frequent in late HAP?

A
  • Acinetobacter spp
  • Pseudomonas
  • Methicillin-resistant S aureus (MRSA).
174
Q

What is a lung abscess?

A

A necrotizing lung infection characterized by a pus-filled cavitary lesion.

175
Q

What is the most common cause of lung abscess?

A

Aspiration of oral secretions.

176
Q

What are the risk factors of aspiration?

A
  1. Depressed levels of consciousness: drug or alcohol use, seizures, general anesthesia, CNS disease. 2. Impaired deglutition: esophageal disease, neurologic disorders, tracheal or nasogastric tubes. 3. Periodontal disease & poor dental hygiene.
177
Q

Which bacteria are commonly involved in aspiration pneumonia?

A

Anaerobic bacteria: *Prevotella melaninogenica, *Peptostreptococcus, *Fusobacterium nucleatum, *Bacteroides species.

178
Q

What diseases can be caused by anaerobic bacteria?

A

*Abscesses (Lung abscess), *Actinomycosis, *Botulism, *Clostridium-difficile-induced colitis, *Food poisoning, *Gas gangrene, *Tetanus.

179
Q

What is the typical clinical picture of a lung abscess?

A

Typical symptoms: Productive cough, fever, sweats, weight loss. Less frequent symptoms: hemoptysis, pleuritic chest pain.

180
Q

How is a lung abscess typically diagnosed?

A

Chest x-ray, CT scan.

181
Q

What is the usual treatment for a lung abscess?

A

Combination beta-lactam/beta-lactamase inhibitor or a carbapenem.

182
Q

What is tuberculosis (TB)?

A

One of the oldest diseases known to affect humans, top cause of infectious death worldwide excluding COVID-19.

183
Q

What is the estimated annual incidence of new TB cases?

A

Approximately 7.0 million new cases annually.

184
Q

What is the common agent of human disease in the Mycobacterium family?

A

M. tuberculosis.

185
Q

What is the shape and size of M. tuberculosis?

A

Rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 μm by 3 μm.

186
Q

What characteristic justifies the classification of M. tuberculosis as acid-fast bacilli?

A

Once Gram-stained, the bacilli cannot be decolorized by acid alcohol.

187
Q

How is M. tuberculosis primarily transmitted?

A

By droplet nuclei from a person with infectious pulmonary TB aerosolized by coughing, sneezing, or speaking.

188
Q

What are the transmission risk factors for tuberculosis?

A
  1. Exogenous: crowding in poorly ventilated rooms, sputum smear-positive cases. 2. Endogenous: degree of immune competence, HIV-infected patients, cancer treatment, immunosuppressive drugs.
189
Q

What is primary TB?

A

Clinical illness directly following infection, common among children and immunocompromised persons, may be severe.

190
Q

What occurs in post-primary TB in adults?

A

Reactivation or reinfection later in life, frequent cavitation, more often infectious than primary disease.

191
Q

What are the possible systemic symptoms of tuberculosis?

A

Fatigue, nocturnal sweating, increased temperature, weight loss, cough with expectoration of mucous or mucous-purulent sputum, hemoptysis.

192
Q

What is the purpose of the tuberculin test?

A

To determine exposure to M. tuberculosis.

193
Q

What indicates active infection in a tuberculin test?

A

Induration of more than 15 mm.

194
Q

What is the BCG vaccine used for?

A

Immunization against tuberculosis in newborn children and revaccination in tuberculin-negative 11-year-old children.

BMS 250 test 2 (11 decks)

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