Microbiology & Pathogen Exam 4 : Mycobacteria, Tuberculosis,
Hansen’s Disease, Atypical Pneumonia, Mycoplasma, Legionella,
Fungi, Dimorphic Pathogens, Candida, Aspergillus, Cryptococcus,
Opportunistic vs Primary Mycoses, Sterols, Ergosterol, Antifungal
Therapy, Protists, Apicomplexans, Toxoplasma, Plasmodium,
Helminths, Nematodes, Cestodes, Trematodes, Enterobius, Taenia,
Parasite Life Cycles, Vector-Borne Transmission, African & American
Trypanosomiasis, Leishmaniasis, Immunity, Virulence Factors,
Glycocalyx, ECM, Endomembrane System, Flagella & Cilia, Gram Stain,
Acid-Fast Bacteria, Binary Fission, Morphology, Antibiotic Resistance,
Multidrug Regimens, Vaccines & BCG, Pathogen Epidemiology Exam
Questions Verified and Provided with Complete A+ Graded Rationales
Latest Updated 2026
What is mycobacteria?
slow growing, aerobic to microaerophilic bacteria.
Characteristics of mycobacteria cell wall
the main virulence factor for mycobacteria is a mycolic-acid rich cell wall that has unique, thick,
hydrophobic fatty acids. this makes the cell resistant to chemicals, acids, dehydration, and
detergents.
,Not visible when gram stained
Mycobacteria that causes human disease
mycobacteria tuberculosis, mycobacterium leprae/mycobacterium lepromatosis, non-
tuberculosis mycobacteria
Mycobacterium tuberculosis
a human respiratory tract pathogen.
can present as pulmonary TB or extrapulmonary TB
Pulmonary vs extrapulmonary TB
disease caused my mycobacterium tuberculosis
pulmonary TB: the most common disease manifestation, the bacteria stays in the lungs
Extrapulmonary TB: the mycobacterium infection makes it's way outside of the respiratory tract
and infects virtually any part of the body (heart, bones, GI, nervous system, lymph nodes, etc.)
Mycobacterium tuberculosis epidemiology
humans are the only known resevoir for mycobacterium TB, and the bacteria has co-evolved
with humans. known as one of the deadliest infectious diseases for humans worldwide. 100%
fatal if untreated and occurs more in those with a weak immune system (immunocompromised
and HIV pts)
Mycobacterium tuberculosis transmission
,transmitted through infectious respiratory droplets emitted from someone with pulmonary TB.
if transmitted to another person there are 3 clinical outcomes:
1. the bacteria does not become established and is eliminated by the body
2. inhaled Mtb is not fully eliminated in the body but is contained in granuloma; the person is in
latent (asymptomatic disease), about 1/3 of the world's population
3. a person with latent TB may contract active TB when the bacteria makes it's way out of the
granulomas. can take place immediately or decades after initial infection.
Symptoms of tuberculosis infection
chronic, productive cough with bloody sputum, fever, weightloss, nightsweats, fatigue, loss of
appetite, shortness of breath, pale skin (blood loss).
If extrapulmonary, symptoms depend on the site of infection.
People at risk for TB
those in close contact with active TB patient, living in an area with high TB rates, people who are
immunocompromised due to medical or socioeconomic factors (organ transplant, HIV, poverty,
malnutrition)
TB detection and diagnosis
a tuberculosis skin test consists of an injection or mycobacterial purified protein derivative
under the 1st layer of the skin in the forearm. Can detect both active and latent infections but
cannot distinguish the difference.
Diagnosis of active TB depends on clinical manifestations, adnormal chest radiograph, acid-fast
bacili in sputum, and NAAT test of sputum.
, TB treatment
both active and latent TB is curable with multidrug antimicrobial therapy.
active TB needs 6-9 months of a 4 drug regimen
latent TB needs 4-6 months of phrophylactic AB
multidrug resistant TB is becoming a growing worldwide problem
TB prevention
BCG (M. Bovis) vaccine used in select countries with high childhood TB rates, but not effective
against adult pulmonary TB rates and can give false positive test results.
It is also important to ID and treat people with active AND latent infections to prevent the
spread.
Test routinely for TB if you travel or live in a high risk area.
Mycobacterium leprae characteristics
slow growing, obligate intracellular AFB. has the longest doubling time of almost any bacteria
and it is very hard to grow. prefers cooler temps and likes foot pads/armadillos.
How does mycobacterium leprae infect the body
the bacteria invades skin macrophages and schwann cells, inducing skin leisons and neurological
injury
Hansen's disease
a chronic, granulomatous diease that slowly progresses and results in inflammatory granulomas
in the skin and peripheral nerves.
Hansen’s Disease, Atypical Pneumonia, Mycoplasma, Legionella,
Fungi, Dimorphic Pathogens, Candida, Aspergillus, Cryptococcus,
Opportunistic vs Primary Mycoses, Sterols, Ergosterol, Antifungal
Therapy, Protists, Apicomplexans, Toxoplasma, Plasmodium,
Helminths, Nematodes, Cestodes, Trematodes, Enterobius, Taenia,
Parasite Life Cycles, Vector-Borne Transmission, African & American
Trypanosomiasis, Leishmaniasis, Immunity, Virulence Factors,
Glycocalyx, ECM, Endomembrane System, Flagella & Cilia, Gram Stain,
Acid-Fast Bacteria, Binary Fission, Morphology, Antibiotic Resistance,
Multidrug Regimens, Vaccines & BCG, Pathogen Epidemiology Exam
Questions Verified and Provided with Complete A+ Graded Rationales
Latest Updated 2026
What is mycobacteria?
slow growing, aerobic to microaerophilic bacteria.
Characteristics of mycobacteria cell wall
the main virulence factor for mycobacteria is a mycolic-acid rich cell wall that has unique, thick,
hydrophobic fatty acids. this makes the cell resistant to chemicals, acids, dehydration, and
detergents.
,Not visible when gram stained
Mycobacteria that causes human disease
mycobacteria tuberculosis, mycobacterium leprae/mycobacterium lepromatosis, non-
tuberculosis mycobacteria
Mycobacterium tuberculosis
a human respiratory tract pathogen.
can present as pulmonary TB or extrapulmonary TB
Pulmonary vs extrapulmonary TB
disease caused my mycobacterium tuberculosis
pulmonary TB: the most common disease manifestation, the bacteria stays in the lungs
Extrapulmonary TB: the mycobacterium infection makes it's way outside of the respiratory tract
and infects virtually any part of the body (heart, bones, GI, nervous system, lymph nodes, etc.)
Mycobacterium tuberculosis epidemiology
humans are the only known resevoir for mycobacterium TB, and the bacteria has co-evolved
with humans. known as one of the deadliest infectious diseases for humans worldwide. 100%
fatal if untreated and occurs more in those with a weak immune system (immunocompromised
and HIV pts)
Mycobacterium tuberculosis transmission
,transmitted through infectious respiratory droplets emitted from someone with pulmonary TB.
if transmitted to another person there are 3 clinical outcomes:
1. the bacteria does not become established and is eliminated by the body
2. inhaled Mtb is not fully eliminated in the body but is contained in granuloma; the person is in
latent (asymptomatic disease), about 1/3 of the world's population
3. a person with latent TB may contract active TB when the bacteria makes it's way out of the
granulomas. can take place immediately or decades after initial infection.
Symptoms of tuberculosis infection
chronic, productive cough with bloody sputum, fever, weightloss, nightsweats, fatigue, loss of
appetite, shortness of breath, pale skin (blood loss).
If extrapulmonary, symptoms depend on the site of infection.
People at risk for TB
those in close contact with active TB patient, living in an area with high TB rates, people who are
immunocompromised due to medical or socioeconomic factors (organ transplant, HIV, poverty,
malnutrition)
TB detection and diagnosis
a tuberculosis skin test consists of an injection or mycobacterial purified protein derivative
under the 1st layer of the skin in the forearm. Can detect both active and latent infections but
cannot distinguish the difference.
Diagnosis of active TB depends on clinical manifestations, adnormal chest radiograph, acid-fast
bacili in sputum, and NAAT test of sputum.
, TB treatment
both active and latent TB is curable with multidrug antimicrobial therapy.
active TB needs 6-9 months of a 4 drug regimen
latent TB needs 4-6 months of phrophylactic AB
multidrug resistant TB is becoming a growing worldwide problem
TB prevention
BCG (M. Bovis) vaccine used in select countries with high childhood TB rates, but not effective
against adult pulmonary TB rates and can give false positive test results.
It is also important to ID and treat people with active AND latent infections to prevent the
spread.
Test routinely for TB if you travel or live in a high risk area.
Mycobacterium leprae characteristics
slow growing, obligate intracellular AFB. has the longest doubling time of almost any bacteria
and it is very hard to grow. prefers cooler temps and likes foot pads/armadillos.
How does mycobacterium leprae infect the body
the bacteria invades skin macrophages and schwann cells, inducing skin leisons and neurological
injury
Hansen's disease
a chronic, granulomatous diease that slowly progresses and results in inflammatory granulomas
in the skin and peripheral nerves.
