Bordetella pertussis, Pseudomonas aeruginosa, Anthrax, Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium leprae

Cystic Fibrosis is caused by a mutation in which specific protein?

The CFTR (CF transmembrane conductance regulator) chloride channel.

What effect does a CFTR mutation have on the lung’s mucin layer?

It produces a thick, salty mucin layer.

What is the Gram stain and morphology of Pseudomonas aeruginosa?

Gram-negative rod.

Does Pseudomona aeruginosa need oxygen to survive?

P. aeruginosa is a facultative aerobe. Meaning it can survive with or without oxygen.

Which bacterial structure allows P. aeruginosa to bind to the upper respiratory tract (URT)?

Pili.

In the lower respiratory tract (LRT), what does the P. aeruginosa CHO capsule bind to?

Mucin.

What is the function of the enzyme elastase produced by P. aeruginosa?

It decreases elastin in lung tissue and blood vessel walls.

How does P. aeruginosa elastase affect the host’s blood clotting?

It degrades clotting factors.

What is the specific biochemical mechanism of P. aeruginosa Exotoxin A (ExoA)?

It causes ADPR of EF-2, similar to Diphtheria Toxin.

To which host receptor does P. aeruginosa ExoA bind?

Low density lipoprotein receptor-related protein.

What is the target of P. aeruginosa Exoenzyme S (ExoS) via the type 3 secretion system (T3SS)?

ADPR of G proteins.

How does P. aeruginosa neuraminidase facilitate infection?

It cleaves sialic acid to expose host cell receptors.

What is the physiological consequences of phospholipase production by P. aeruginosa?

It decreases lung surfactants, leading to alveolar collapse.

What finding in a sweat test is indicative of Cystic fibrosis?

An increased level of chloride (Cl^-) because it can’t be reabsorbed.

What does an increased level of immunoreactive trypsinogen (IRT) in the blood suggest in a newborn?

CF pancreatic disease causing blocked pancreatic ducts.

Why is antibiotic resistance a significant problem for P. aeruginosa treatment?

Its capsule and LPS act as an intrinsic barrier.

Which stage of Bordetella pertussis infection is the most contagious?

The catarrhal stage (weeks 0-2).

During which stage of Pertussis is antibiotic treatment most effective at decreasing disease severity?

The catarrhal stage.

What clinical sign defines the paroxysmal stage of Pertussis?

A rapid cough followed by a “whoop” sound (weeks 2-8).

Why do antibiotics fail to reduce symptoms during the paroxysmal Pertussis?

The symptoms are caused by toxins, not the bacteria themselves.

To which specific structure in the nasopharynx does Pertussis attach?

The cilia.

What is teh function of Filamentous Hemagglutinin (FHA) in Pertussis pathogenesis?

It binds to ciliated cell and phagocytes.

What is the biochemical effect of Pertussis Toxin (PT) on host cells?

It causes ADPR of G_i, leading to an increase cAMP.

What is the typical duration of the Pertussis convalescent stage?

8 to 12 weeks.

In inhalation anthrax, where do spored typically germinate within minutes?

In lung macrophages.

What is the primary component of the human anthrax vaccine used in the US?

Protective Antigen (PA).

Why is quarantine unnecessary for anthrax outbreaks?

There is no human-to-human transmission.

What is the Gram stain-like morphology and xygen requirement of Mycobacterium tuberculosis?

Gram-positive like rod. It is an obligate aerobe, meaning it needs oxygen to survive.

Which staining method is used to identify Mycobacterium species?

Acid-fast staining.

Approximately what percentage of individuals with a latent TB infection (LTBI) will develop active disease?

5-10%

Which immune cell releases IFN-γ to activate macrophages during a TB infection?

CD4+ T cells.

What is a ‘Ghon complex’ in the context of tuberculosis?

Calcified scar tissue formed by tubercle maturation, visible on chest X-rays.

What is the primary difference between primary TB and secondary TB?

Primary occurs upon initial infection, secondary is the reactivation of LTBI.

In a TST (PPD) test, what does ‘induration’ specifically refer to?

A hard, raised area caused by macrophage and fibrin deposition.

What size of induration is considered a positive TST result for a person with no risk factors?

>15mm.

Why might an HIV patient show a negative PPD test despite having TB?

They may experience anergy (inability to mount an immune response).

What is the primary advantage of the IGRA blood test over the TST for TB?

It works on BCG-vaccinated individuals without giving a false positive.

Which species accounts for 80% of Nontuberculosis Mycobacteria (NTM) cases in the US?

M. avium compex (MAC).

What is the primary reservoir for Mycobacterium bovis?

Cattle and other animals.

How is Mycobacterium bovis most commonly spread to humans?

Consumption of unpasteurized milk or inhalation from animals.

The standrad TB vaccine (BCG) is an attenuated strain of which organism?

Mycobacterium bovis.

Which animal serves as a natural reservoir for Mycobacterium leprae in addition to humans?

Armadillos.

Which structures are primarily affected by Mycobacterium leprae?

Skin, nerves, and mucous memebranes.

What is the role of Type IV pili in Neisseria meningitidis pathogenesis?

Adherence to the nasopharynx and breaching the blood-brain-barrier (BBB).

Which virulence factor of Neisseria meningitidis is responsible for significant inflammation and tissue damage?

Lipo-oligosaccharide (LOS).

Which 6 serogroups cause almost all reported cases of invasive meningococcal disease?

A, B, C, W, X, and Y.

What is the purpose of the sIgA protease in Neisseria meningitidis?

To help the bacteria survive the upper respiratory tract (URT).

What diagnostic method is used for Neisseria meningitidis if antibiotics were administered before culture?

PCR (due to low bacterial count).

What is the Gram stain and shape of Neisseria meningitidis?

Gram-negative diplococcus.

How does Neisseria meningitidis enter the cerebrospinal fluid (CSF)?

By crossing the blood-brain barrier (BBB).

The MenACWY vaccine is what type of vaccine?

Meningococcal conjugate vaccine.

Which N. meningitidis virulence factor allows for capsular switching?

The polysaccharide capsule.

What type of organism is Pseudomonas aeruginosa in terms of its role in disease?

An opportunistic pathogen.

What happens to host ciliated cells during a Bordetella pertussis infection?

They stop beating, which prevents the clearing of debris and mucus.

Which diagnostic test for TB measures the release of IFN-γ from pre-primed T cells?

IGRA (Interferon-Gamma Release Assay).

What is the oxygen requirement for Mycobacterium tuberculosis?

Obligate aerobe, which means it needs oxygen to grow.

What percentage of primary TB cases are pulmonary (PTB)?

90%.

How is Mycobacterium leprae typically spread betwene people?

Through air droplets.

What is the mortality rate of untreated inhalation anthrax once it becomes systemic?

Up to 100%.

Which enzyme produced by P. aeruginosa degrades host IgG and IgA?

Elastase.

In the context of P. aeruginosa, what is the significance of the CHO capsule binding to mucin?

It allows for bacterial adherence in the lower respiratory tract.

How many doses are in the standard US human anthrax vaccine schedule?

5 doses with yearly boosters.

What is the common name for disease caused by Bordetella pertussis?

Whooping cough.

Why does P. aeruginosa thrive in the lungs of CF patients?

The thick mucin and impaired lung defenses provide an ideal environment.

Which stage of Pertussis is also known as the ‘toxemic stage’?

The paroxysmal stage.

What is the reservoir for MAC(M. avium complex)?

Soil, water, and animals.

What type of disease does M. bovis typically cause in humans?

Extrapulmonary TB (affecting lympgh nodes, joints, and bone).

Which N. meningitidis vaccine is specifically a recombinant subunit vaccine?

Meningitis B (MenB).

What is the term for the redness and swelling observed in a positive TST?

Erythema.

How long does it typically take for a person to test positive on a TST after initial TB infection?

Approximately 1 month.

What is the function of host calmodulin in pertussis pathogenesis?

It is required for the bacterial adenylate cyclase toxin to increase cAMP.