Respiratory Infections in Special Populations Flashcards
What is bronchiectasis?
A condition where the bronchi are permanently damaged, widened and thickened.
What is the consequence of bronchiectasis?
Damaged airways allow mucous build-up and bacteria to accumulate
= Multiple infections
How is bronchiectasis cured?
Cannot be cured, but can be managed
What mutation causes cystic fibrosis?
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene mutation
What is the function of CFTR?
- channel that transports chloride into and out of cells
- regulates the passage of other ions and chemicals
- found in the epithelial cells of: lung, digestive system, sweat glands
What is the mode of inheritance of cystic fibrosis?
Autosomal recessive
What does a CFTR mutation result in?
Inappropriate movement of chloride through cells
- result = thick and sticky mucous in the lungs and digestive system
Why do cystic fibrosis patients have chronic lung infections?
- thick and dehydrated mucus is produced throughout the respiratory tract, especially in the small airways
- the mucus is difficult to clear from the airways
- the extra mucus leads to symptoms such as chronic cough
- the abnormal mucus results in bacteria adhering to it
= Ultimately causes chronic lung infection
What organisms are associated with colonization and infection in cystic fibrosis patients?
- Staphylococcus Aureus
- Pseudomonas Aeruginosa
- Haemophilus Influenzae
- Stenotrophomonas Maltophilia
- Burkholderia Cepacia Complex
- Non-tuberculosis Mycobacteria
- Candida spp.
- Aspergillus spp.
and other bacteria…
What is significant about colonization and infection with Staphylococcus Aureus in the CF population?
- GPC clusters
- one of the most common pathogens at any stage
- difficult to eradicate
- develops resistance to Beta-lactams… MRSA
What is significant about colonization and infection with Pseudomonas Aeruginosa in the CF population?
- GNB = common cause of chronic infections
- FORMS BIOFILMS!
- difficult to eradicate
- prone to multi-drug resistance (MDR)
- patients receive multiple courses of antibiotics
What is significant about colonization and infection with Haemophilus Influenzae in the CF population?
- GNB
- more common in younger patients
- often not a chronic pathogen
What is significant about colonization and infection with Stenotrophomonas Maltophilia in the CF population?
- GNB
- less common
- intrinsically MDR
- few treatment options
What is significant about colonization and infection with Burkholderia Cepacia Complex in the CF population?
- GNB
- less common
- usually occurs in older patients
- prone to chronic colonization
- certain species and genotypes associated with poor outcomes and are even a CONTRAINDICATION TO LUNG TRANSPLANTATION
- intrinsically MDR
- few treatment options
What is significant about colonization and infection with Non-Tuberculosis Mycobacteria in the CF population? Which species are associated?
Species: M. Avium Intracellulare
- significance unknown
- long duration of treatment
What is significant about colonization and infection with Candida spp. in the CF population?
- a known commensal of the mouth
- can become pathogenic in certain patients
What is significant about colonization and infection with Aspergillus spp. in the CF population?
- ubiquitous organism
- spores found widely in the environment
- can cause ABPA of carying severities
What are some of the other bacteria that cause infections in cystic fibrosis patients?
Any other bacterial pathogen can infect these patients:
- A. Xylosoxidans
- TB
- E. coli
- Klebsiella Pneumoniae
Cystic Fibrosis patients usually have what symptoms in colonization and infection?
These patients normally have chronic cough (productive, may be purulent), wheeze, signs of respiratory impairment, bronchiectasis
What is seen in colonization of cystic fibrosis patients?
The normal symptoms + isolation of typical bacteria (no deterioration of lung function)
What is seen in infection of cystic fibrosis patients?
Increased volume of purulent sputum, dyspnoea, wheeze, chest pain, CXR may be normal, fever is unusual
How is diagnosis of infection made in cystic fibrosis patients?
Most respiratory sample types are accepted for MC&S (including throat swabs)
- additional culture media is used for testing to improve likelihood of isolating a pathogen
- important to let the laboratory know that the sample has been taken from a patient with CF
How are cystic fibrosis patients managed?
Once diagnosed with CF, patients must be referred to a Pulmonologist (Paediatric or Adult Physician)
- specialist CF treatment centers in SA
Nocardia epidemiology
Environmental saprophytes
