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BMS 250 test 2 > Week 6 Lecture 3 > Flashcards

Week 6 Lecture 3 Flashcards

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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
What are common risk factors for typical community-acquired pneumonia?
Defects in normal defense mechanisms or overwhelming virulent pathogens.
26
What is a significant characteristic of Pseudomonas aeruginosa?
Can cause localized and systemic illness in virtually any tissue or organ.
27
What is the primary cause of subacute bacterial endocarditis?
S. viridans.
28
What are the two types of diseases caused by S. pyogenes?
* Pyogenic diseases * Toxigenic diseases * Immunologic diseases
29
What is the primary role of IgA protease in S. pneumoniae?
Enhances the organism’s ability to colonize the mucosa of the upper respiratory tract by cleaving IgA.
30
True or False: All streptococci are catalase positive.
False ## Footnote All streptococci are catalase negative.
31
What are the two main risk factors for pneumonia?
A) defect in normal defense mechanisms B) large infectious inoculum or virulent pathogen
32
What are the risk factors for infection by common pathogens in typical CAP?
Risk factors include age, comorbidities, and smoking.
33
What are the most common bacterial pathogens in CAP?
* Streptococcus pneumoniae * Haemophilus influenzae * Staphylococcus aureus
34
What are the most common viral causes of CAP?
* coronaviruses (SARS-CoV-2, MERS) * influenza virus * respiratory syncytial virus * Adenovirus * Parainfluenza virus
35
Name two uncommon pathogens associated with pneumonia.
* Chlamydophila psittaci * Coxiella burnetii
36
What are the three widely available diagnostic tests for CAP?
* Sputum Gram stain and culture * Urinary antigen tests for S. pneumoniae and Legionella species * Tests for viruses such as influenza and SARS-CoV-2
37
List clinical findings indicative of CAP.
* 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
38
What characterizes typical pneumonia on an X-Ray?
X-Ray corresponds with clinical findings on physical examination.
39
Define lobar pneumonia.
Acute exudative inflammation of an entire lobe with uniform consolidation.
40
What are the updated recommendations for pneumococcal vaccines in adults over 65?
* 20-valent pneumococcal conjugate vaccine (PCV20) * Sequential administration of PCV15 and PPSV23
41
What is the transmission method for Mycoplasma pneumoniae?
Transmitted by respiratory droplets.
42
True or False: Chlamydia pneumoniae has a seasonal incidence.
False
43
What are the distinguishing features of nosocomial pneumonia?
* Different infectious causes * Different antibiotic susceptibility patterns * Poorer underlying health status of patients
44
What is the most common cause of hospital-acquired pneumonia (HAP)?
Streptococcus species.
45
What factors increase the risk for hospital-acquired pneumonia?
* Instrumentation of the upper airway * Contact with contaminated aerosols * Treatment with broad-spectrum antibiotics
46
What characterizes ventilator-associated pneumonia (VAP)?
New pneumonia developing > 48 hours following endotracheal intubation.
47
What is the microbiology of early hospital-acquired pneumonia?
* Enteric gram-negative bacilli * Haemophilus influenzae * Staphylococcus aureus * Streptococcus pneumoniae
48
What is a lung abscess?
A necrotizing lung infection characterized by a pus-filled cavitary lesion.
49
What are common causes of lung abscesses?
* Aspiration of oral secretions * Endobronchial obstruction * Hematogenous seeding
50
What is the most common microbiological cause of lung abscess?
Anaerobic bacteria.
51
What is the primary clinical picture of a lung abscess?
* Productive cough * Fever * Weight loss
52
What is the definition of tuberculosis?
One of the oldest diseases affecting humans, caused by Mycobacterium tuberculosis.
53
What is the transmission method for Mycobacterium tuberculosis?
Aerosolized droplet nuclei from an infected person.
54
What are risk factors for active tuberculosis?
* Crowding in poorly ventilated rooms * Immunocompromised status * Endogenous factors like innate immunologic defenses
55
What does the Tuberculin test indicate?
Induration of more than 15 mm indicates active infection.
56
What is the role of BCG vaccination?
Primovaccination of healthy newborns and revaccination of tuberculin-negative children.
57
Who developed the staining method using crystal violet dye?
Hans Christian Gram ## Footnote The staining method was developed in 1884.
58
What color do Gram-positive bacteria stain?
BLUE
59
What color do Gram-negative bacteria stain?
RED
60
Why do Gram-negative and Gram-positive bacteria stain differently?
Their cell walls are different
61
What are the two classifications of bacteria based on oxygen requirements?
Aerobic and Anaerobic
62
What do aerobic bacteria need for growth?
Oxygen
63
What difficulties do anaerobic bacteria face?
Difficulties to grow when oxygen is present
64
Where is a large part of the normal resident flora located?
Mucous membranes: mouth, lower gastrointestinal tract, and vagina
65
What can cause disease when mucous membranes are disrupted?
Anaerobes from normal flora
66
What are the three morphological classifications of bacteria?
Spherical (cocci), Cylindric (bacilli), Spiral (spirochetes)
67
Name two important human pathogens that are Gram-positive cocci.
Staphylococcus aureus and Streptococcus pyogenes
68
How do staphylococci appear microscopically?
In grapelike clusters
69
How do streptococci appear microscopically?
In chains
70
What biochemical property differentiates staphylococci from streptococci?
Staphylococci produce catalase; streptococci do not
71
What is the arrangement of Staphylococcus aureus?
Spherical gram-positive cocci in irregular grapelike clusters
72
What important virulence factor does Staphylococcus aureus produce?
Catalase
73
List three species of Staphylococcus.
* S. aureus * S. epidermidis * S. saprophyticus
74
What primarily distinguishes S. aureus from other Staphylococcus species?
Coagulase production
75
What is a significant characteristic of S. aureus in terms of antibiotic resistance?
Production of beta-lactamase
76
Where is the main site of colonization for S. aureus?
The nose
77
What percentage of people are approximately colonized by S. aureus at any one time?
30%
78
What is an important mode of transmission for S. aureus?
Hand contact
79
What can decrease transmission of S. aureus?
Handwashing
80
Name one of the three exotoxins produced by S. aureus.
Enterotoxin, Toxic Shock Syndrome Toxin, or Exfoliatin
81
What does enterotoxin cause?
Food poisoning
82
In which individuals can Toxic Shock Syndrome Toxin cause toxic shock?
In tampon-using menstruating women, individuals with wound infections, patients with nasal packing
83
What condition does Exfoliatin cause in young children?
Scalded-skin syndrome
84
What localized production of S. aureus results in bullous impetigo?
Exfoliatin
85
What type of inflammation is induced by S. aureus?
Pyogenic (pus-producing) inflammation. ## Footnote S. aureus causes disease through toxins and pyogenic inflammation.
86
List three typical lesions caused by S. aureus.
* Abscess * Folliculitis * Impetigo
87
What are predisposing factors to infection by S. aureus?
* Foreign bodies * Sutures * Intravenous catheters
88
What type of bacteria are streptococci?
Spherical gram-positive cocci arranged in chains or pairs. ## Footnote All streptococci are catalase negative.
89
How are streptococci classified?
Into groups A–U (Lancefield groups) based on antigenic differences in C carbohydrate.
90
What is the most important human pathogen among Group A streptococci?
S. pyogenes.
91
What is the leading bacterial cause of pharyngitis?
S. pyogenes.
92
Define α-hemolytic streptococci.
Streptococci that produce a green zone around their colonies due to incomplete lysis of red blood cells.
93
Define β-hemolytic streptococci.
Streptococci that produce a clear zone around their colonies due to complete lysis of red blood cells.
94
What causes β-hemolysis in streptococci?
The production of enzymes (hemolysins) called streptolysin O and streptolysin S.
95
What is the main transmission route for streptococci?
Most are part of the normal flora of the human throat, skin, and intestines.
96
Where is S. pyogenes typically found in the body?
On the skin and in the oropharynx in small numbers.
97
Which streptococcus is known for causing neonatal sepsis and meningitis?
S. agalactiae (Group B Streptococcus).
98
What are the three types of diseases caused by S. pyogenes?
* Pyogenic diseases * Toxigenic diseases * Immunologic diseases
99
What is a common cause of subacute bacterial endocarditis?
S. viridans.
100
What types of infections is Streptococcus pneumoniae associated with?
* Pneumonia * Bacteremia * Meningitis * Upper respiratory tract infections (otitis media, mastoiditis, sinusitis)
101
What is the significance of pneumococci in community-acquired pneumonia?
They are the most common cause.
102
What does the name 'Streptococcus' derive from?
From the Greek words 'streptos' meaning 'twisted' and 'kokkos' meaning 'berry'.
103
Fill in the blank: α-hemolytic streptococci produce a _______ color on blood agar.
greenish
104
What molecules have been identified within the pneumococcal cell that may play a role in pathogenesis and virulence?
Many molecules within the cytoplasm, cell membrane, and cell wall ## Footnote These include key antigens and factors contributing to virulence.
105
What role do polysaccharide capsules play in S. pneumoniae pathogenesis?
Interfere with phagocytosis ## Footnote Polysaccharide capsules are a key virulence factor.
106
What is C-reactive protein (CRP)?
An 'acute-phase' protein that is elevated in acute inflammation ## Footnote CRP is not an antibody but rather a β-globulin.
107
How much can CRP be elevated during acute inflammation?
Up to 1000-fold ## Footnote This elevation is a nonspecific indicator of inflammation.
108
What is a key characteristic that distinguishes CRP from antibodies?
CRP is a β-globulin, while antibodies are γ-globulins ## Footnote This distinction is important in understanding immune responses.
109
What does elevated CRP indicate in clinical practice?
A better predictor of heart attack risk than elevated cholesterol levels ## Footnote This highlights the clinical significance of CRP measurement.
110
What is pneumolysin?
A hemolysin that causes α-hemolysis and may contribute to pathogenesis ## Footnote Pneumolysin is another virulence factor of S. pneumoniae.
111
What is the function of IgA protease produced by pneumococci?
Enhances the organism’s ability to colonize the mucosa by cleaving IgA ## Footnote This helps pneumococci evade the immune response.
112
What happens when pneumococci reach the alveoli?
Outpouring of fluid and red and white blood cells, resulting in lung consolidation ## Footnote This is part of the inflammatory response to infection.
113
What occurs during recovery from pneumococcal infection?
Pneumococci are phagocytized, mononuclear cells ingest debris, and consolidation resolves ## Footnote This process is crucial for healing.
114
What is the natural host for pneumococci?
Humans ## Footnote There is no animal reservoir for pneumococci.
115
What percentage of the healthy population can carry pneumococci in the oropharynx?
5%–50% ## Footnote This indicates the prevalence of asymptomatic carriers.
116
What are some predisposing factors for pneumococcal disease?
1) Alcohol or drug intoxication 2) Abnormality of the respiratory tract 3) Abnormal circulatory dynamics 4) Splenectomy 5) Certain chronic diseases ## Footnote These factors increase the risk of developing disease.
117
Name two Gram-negative bacteria associated with respiratory infections.
1) Haemophilus influenzae 2) Klebsiella pneumoniae ## Footnote These bacteria are significant pathogens in respiratory disease.
118
What type of infections does Haemophilus influenzae typically cause?
Normal component of the upper respiratory tract flora ## Footnote It can cause various infections when it overgrows or enters sterile areas.
119
What is Bordetella pertussis known for causing?
Pertussis (whooping cough) ## Footnote It is an important cause of morbidity and mortality worldwide.
120
What is a significant effect of pertussis vaccines?
Lowering the incidence of whooping cough ## Footnote Vaccination has significantly impacted public health.
121
What types of illnesses can Pseudomonas aeruginosa cause?
Localized and systemic illness affecting virtually any tissue or organ ## Footnote It is particularly problematic in immunocompromised individuals.
122
In what conditions is Klebsiella pneumoniae particularly dangerous?
Necrotizing lobar pneumonia in individuals compromised by alcoholism, diabetes, or COPD ## Footnote It is associated with severe infections in at-risk populations.
123
What type of organism is Klebsiella pneumoniae?
Large, nonmotile bacilli that produce an abundant capsule ## Footnote This capsule contributes to its virulence.
124
What are the bacteria causing atypical pneumonia?
Legionella, Mycoplasma pneumoniae, Chlamydia trachomatis ## Footnote These bacteria are known for causing atypical presentations of pneumonia.
125
What is Legionnaires disease?
An atypical, acute lobar pneumonia with multisystem symptoms that can occur sporadically or in outbreaks ## Footnote It is often associated with the inhalation of contaminated aerosols or aspiration of water containing Legionella.
126
What are the two main categories of pneumonia?
1. Community-acquired pneumonia (CAP) 2. Nosocomial pneumonia ## Footnote Nosocomial pneumonia includes hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).
127
What are the types of community-acquired pneumonia (CAP)?
1. Typical CAP (S. pneumoniae) 2. Atypical CAP (Mycoplasma, Chlamydia, Legionella) ## Footnote These types are differentiated by the causative organisms.
128
What are the first line of defense mechanisms in innate immunity for respiratory infections?
1. Intact respiratory epithelium; cough reflex 2. Nonspecific or innate immune factors ## Footnote These factors include mucus, immunoglobulin A, cytokines, splenic function, complement, neutrophils, and macrophages.
129
What is acquired immunity in the context of pneumonia?
Induced following colonization or exposure to cross-reactive antigens leading to the development of serum IgG antibodies ## Footnote This immunity is crucial for responding to pneumococcal infections.
130
What is the risk associated with infants and agammaglobulinemia regarding pneumonia?
High risk of pneumococcal infection due to poorly developed B-cell responses ## Footnote Agammaglobulinemia results in the absence of serum immunoglobulin, increasing susceptibility.
131
What are the conditions that increase the risk of pneumonia?
A) Defect in normal defense mechanisms B) Large infectious inoculum or virulent pathogen ## Footnote These conditions can overwhelm the immune response.
132
What are the most common viral causes of community-acquired pneumonia (CAP)?
coronaviruses (SARS-CoV-2, MERS), influenza virus, respiratory syncytial virus, adenovirus, parainfluenza virus ## Footnote These viruses are frequently implicated in CAP.
133
Fill in the blank: Atypical pneumonia can be caused by _______.
Mycoplasma pneumoniae, Chlamydia trachomatis, Legionella ## Footnote These pathogens lead to atypical presentations of pneumonia.
134
True or False: Typical CAP is primarily associated with Streptococcus pneumoniae.
True ## Footnote S. pneumoniae is the most common bacterial cause of typical community-acquired pneumonia.
135
What are uncommon pathogens that can cause pneumonia?
Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, Blastomyces, Coccidioides, Histoplasma, Sin Nombre virus ## Footnote These pathogens are less frequently associated with pneumonia but can cause significant disease.
136
What are the bacteria causing atypical pneumonia?
Legionella, Mycoplasma pneumoniae, Chlamydia trachomatis ## Footnote These bacteria are known for causing atypical presentations of pneumonia.
137
What is Legionnaires disease?
An atypical, acute lobar pneumonia with multisystem symptoms that can occur sporadically or in outbreaks ## Footnote It is often associated with the inhalation of contaminated aerosols or aspiration of water containing Legionella.
138
What are the two main categories of pneumonia?
1. Community-acquired pneumonia (CAP) 2. Nosocomial pneumonia ## Footnote Nosocomial pneumonia includes hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP).
139
What are the types of community-acquired pneumonia (CAP)?
1. Typical CAP (S. pneumoniae) 2. Atypical CAP (Mycoplasma, Chlamydia, Legionella) ## Footnote These types are differentiated by the causative organisms.
140
What are the first line of defense mechanisms in innate immunity for respiratory infections?
1. Intact respiratory epithelium; cough reflex 2. Nonspecific or innate immune factors ## Footnote These factors include mucus, immunoglobulin A, cytokines, splenic function, complement, neutrophils, and macrophages.
141
What is acquired immunity in the context of pneumonia?
Induced following colonization or exposure to cross-reactive antigens leading to the development of serum IgG antibodies ## Footnote This immunity is crucial for responding to pneumococcal infections.
142
What is the risk associated with infants and agammaglobulinemia regarding pneumonia?
High risk of pneumococcal infection due to poorly developed B-cell responses ## Footnote Agammaglobulinemia results in the absence of serum immunoglobulin, increasing susceptibility.
143
What are the conditions that increase the risk of pneumonia?
A) Defect in normal defense mechanisms B) Large infectious inoculum or virulent pathogen ## Footnote These conditions can overwhelm the immune response.
144
What are the most common viral causes of community-acquired pneumonia (CAP)?
coronaviruses (SARS-CoV-2, MERS), influenza virus, respiratory syncytial virus, adenovirus, parainfluenza virus ## Footnote These viruses are frequently implicated in CAP.
145
Fill in the blank: Atypical pneumonia can be caused by _______.
Mycoplasma pneumoniae, Chlamydia trachomatis, Legionella ## Footnote These pathogens lead to atypical presentations of pneumonia.
146
True or False: Typical CAP is primarily associated with Streptococcus pneumoniae.
True ## Footnote S. pneumoniae is the most common bacterial cause of typical community-acquired pneumonia.
147
What are uncommon pathogens that can cause pneumonia?
Chlamydophila psittaci, Coxiella burnetii, Francisella tularensis, Blastomyces, Coccidioides, Histoplasma, Sin Nombre virus ## Footnote These pathogens are less frequently associated with pneumonia but can cause significant disease.
148
What is the purpose of diagnostic testing in CAP?
To adjust empirically chosen therapy and facilitate epidemiologic analysis.
149
Name three widely available diagnostic tests for CAP.
* 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
What is the typical fever threshold in CAP?
>38°C
151
What leukocyte counts are associated with CAP?
* Leukopenia: <4000 WBC/mm3 * Leukocytosis: ≥12,000 WBC/mm3
152
What altered mental status is significant in adults ≥70 years in CAP?
Altered mental status without an alternative etiology.
153
What are common symptoms indicating CAP?
* 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
What characterizes Typical CAP on an X-ray?
The X-Ray corresponds with clinical findings on physical examination.
155
Define lobar pneumonia.
Acute exudative inflammation of the entire lobe with uniform consolidation.
156
What is the most common cause of lobar pneumonia?
Streptococcus pneumoniae.
157
How does bronchopneumonia differ from lobar pneumonia?
Bronchopneumonia inflames the alveoli with incomplete consolidation within lung regions.
158
What are the updated recommendations for the pneumococcal vaccine?
* 20-valent pneumococcal conjugate vaccine (PCV20) alone * Sequential administration of 15-valent PCV (PCV15) and 23-valent polysaccharide vaccine (PPSV23)
159
In which populations is the pneumococcal vaccine recommended?
* All adults aged 65 years or older * Adults with comorbidities (chronic lung disease, liver disease, diabetes) * Increased risk of meningitis, asplenia, or immunocompromise.
160
What characterizes atypical pneumonia?
The X-Ray does not correspond with clinical findings on physical examination.
161
How is Mycoplasma pneumoniae transmitted?
By respiratory droplets.
162
What percentage of pneumonia cases are attributed to Mycoplasma pneumoniae?
~20%
163
What age group has the highest incidence of Mycoplasma pneumoniae clinical disease?
Older children and young adults (ages 5-20 years).
164
What is a significant respiratory pathogen causing pharyngitis and atypical pneumonia?
Chlamydia pneumoniae.
165
What is Legionnaires disease?
An atypical, acute lobar pneumonia with multisystem symptoms.
166
What distinguishes community-acquired pneumonia from nosocomial pneumonia?
* Different infectious causes * Different antibiotic susceptibility patterns * Poorer underlying health status of patients.
167
What is the definition of hospital-acquired pneumonia (HAP)?
Clinical features and imaging consistent with pneumonia occurring > 48 hours after hospital admission.
168
What is the definition of ventilator-associated pneumonia (VAP)?
New pneumonia developing > 48 hours following endotracheal intubation and mechanical ventilation.
169
List some exogenous risk factors for HAP.
* Instrumentation of the upper airway * Contact with personnel and equipment * Treatment with broad-spectrum antibiotics.
170
What are some patient factors that increase the risk for HAP?
* Malnutrition * Advanced age * Altered consciousness * Swallowing disorders * Underlying pulmonary and systemic diseases.
171
What microbiological agents are common in HAP?
* S aureus (including MRSA) * Streptococcus species * P aeruginosa * Other gram-negative rods.
172
What is the etiology of early HAP?
* Enteric GNB (E coli, K pneumoniae, Proteus, Serratia) * H influenzae * S aureus * S pneumoniae.
173
What organisms are more frequent in late HAP?
* Acinetobacter spp * Pseudomonas * Methicillin-resistant S aureus (MRSA).
174
What is a lung abscess?
A necrotizing lung infection characterized by a pus-filled cavitary lesion.
175
What is the most common cause of lung abscess?
Aspiration of oral secretions.
176
What are the risk factors of aspiration?
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
Which bacteria are commonly involved in aspiration pneumonia?
Anaerobic bacteria: *Prevotella melaninogenica, *Peptostreptococcus, *Fusobacterium nucleatum, *Bacteroides species.
178
What diseases can be caused by anaerobic bacteria?
*Abscesses (Lung abscess), *Actinomycosis, *Botulism, *Clostridium-difficile-induced colitis, *Food poisoning, *Gas gangrene, *Tetanus.
179
What is the typical clinical picture of a lung abscess?
Typical symptoms: Productive cough, fever, sweats, weight loss. Less frequent symptoms: hemoptysis, pleuritic chest pain.
180
How is a lung abscess typically diagnosed?
Chest x-ray, CT scan.
181
What is the usual treatment for a lung abscess?
Combination beta-lactam/beta-lactamase inhibitor or a carbapenem.
182
What is tuberculosis (TB)?
One of the oldest diseases known to affect humans, top cause of infectious death worldwide excluding COVID-19.
183
What is the estimated annual incidence of new TB cases?
Approximately 7.0 million new cases annually.
184
What is the common agent of human disease in the Mycobacterium family?
M. tuberculosis.
185
What is the shape and size of M. tuberculosis?
Rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 μm by 3 μm.
186
What characteristic justifies the classification of M. tuberculosis as acid-fast bacilli?
Once Gram-stained, the bacilli cannot be decolorized by acid alcohol.
187
How is M. tuberculosis primarily transmitted?
By droplet nuclei from a person with infectious pulmonary TB aerosolized by coughing, sneezing, or speaking.
188
What are the transmission risk factors for tuberculosis?
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
What is primary TB?
Clinical illness directly following infection, common among children and immunocompromised persons, may be severe.
190
What occurs in post-primary TB in adults?
Reactivation or reinfection later in life, frequent cavitation, more often infectious than primary disease.
191
What are the possible systemic symptoms of tuberculosis?
Fatigue, nocturnal sweating, increased temperature, weight loss, cough with expectoration of mucous or mucous-purulent sputum, hemoptysis.
192
What is the purpose of the tuberculin test?
To determine exposure to M. tuberculosis.
193
What indicates active infection in a tuberculin test?
Induration of more than 15 mm.
194
What is the BCG vaccine used for?
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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