Trends/epidemiology Flashcards
Trends in organisms in CF
Huge range of organisms can be found
Haemophilus and staph often found in younger patients
Pseudomonas more in teenagers and up
Burkholderia in older patients
NLFs tend to be opportunistic bacteria -> majority are ubiquitous in nature
Unusual fungal infections can be seen in CF patients such as scedosporium
Infections tend to be polymicrobial
Trends in CF organisms in different age cohorts
H influenzae is more common in infancy
S. aureus is more common in younger patients and peaks in teens at about 17
MRSA is more common in young adults peaks at about 20
P. aeruginosa risk worsens with age and peaks at about 40
NLFs such as B cepacia, Stenotrophomons and Achromobacter stay realatively uncommon throughout life
Usually lung very diverse early on, usually even find weird NLFs or fungi etc . As disease progresses pseudomonas becomes more and more dominant until it takes over
CF organisms in patients as trends over time
The amount of S. aureus weve isolated since the 90s has been increasing
The amount of P. aeruginosa weve isolated since the 90s has been decreasing
MRSA isolations have been increasing
H. influenzae have staed relatively the same
Steno and achromobacter have increased
B. cepacia remained the same
*not entirely reflective as detection methods are a lot better now, less likely to miss an MRSA or an NLF nowadays compared to the 90s etc
H. influenzae in CF trends
A common commensal of the upper respiratory tract
A frequent coloniser of infants and children
Seen in 20% of CF children under 1
Seen in 32% of CF children between 2 and 5
May cause acute exacerbations in chronic conditions
Produces IgA1 proteases and can cause ciliostasis
Can decrease mmucociliary cleanance up to 10 fold in CF patients
S. aureus in Cystic Fibrosis
S. aureus is often the first isolate
Can be seen in up to 70% of CF isolates
More common in younger patients/teens etc
Concern with empyema (pus build-up) and lung abscesses
Role of slime and teichoic acid which play a role in adherence to respiratory epithelial cells
Both CA and HA MRSA are seen in CF patients
P. aeruginosa in Cystic Fibrosis
PA is the most prevalent respiratory bacterial pathogen
Higher prevalence in adults
Isolated i about 50% of cf patients
Infection associated with significant morbidity
Mucoid vs non-mucoid
- Non mucoid strains are more commonly seen in young people
- Mucoid strains are more commonly seen in older patients
Epidemic strains e.g. midlands, liverpool and australia associated with CF to CF spread
First positive isolate, antibiotic treatment, second isolate clear, infection treated, only an intermittent infection
Older patient, third isolate positive, antibiotic treatment, repeated positive isolates, chronic infection, not treated
Burkholderia Cepacia CF
Just under 3% of CF patients are infected
Ubiqitous -> found in nature -> opportunistic -> non pathogenic in healthy humans
Can cause long term colonisation without affecting lung function
Can cause chronic infection associated with slowly declining lung function
Can cause acute fulminant lung infection leading to death in weeks/months -> necrotising pneumonia/cepacia syndrome
Deteriorating lung function
More pulmonary exacerbations/hospital admissions
More IV antibiotics
Reduced life expectancy
Hospital segregation
Social isolation
Implications for transplantation
Epidemic strains e.g. ET12
Stenotrophomonas in CF
Found in soil -> mostly community acquired
Tends to be transient and recurrent
Peakas in teens and young adults
Emerging CF bacteria
Achromobacter xylosoxidans
Pandoraea species
Inquilinus Limosus
Herbaspirillum species
Burkholderia gladioli
Streptococcus milleri group (SMG)
These could be potentially transmissible
They could be naturally multi-drug resistant -> think of NLFs
NLFs could be falely identified as BCC (could take patient of transplant list so we need to be aware of them)
Could impact infection control measures
Non TB Mycobacterium in CF
NTMs are ubiqituous
Risk factors for acquisition are not really understood
Increased risk of acquisition if aspergillus isolates found or if on steroid treatment
Can be difficult to diagnose and problematic to treat
Infection strongly associated with age
2 different types: slow growing and rapid growing
- Slow-growing Mycobacterium avium complex (MAC)
(including M. avium, M. intraceulare and M. chimaera)
- Rapid growing M. absessus complex (MABSC)
Aspergillus in CF
Aspergillus causes significant morbidity in CF
Wide spectrum of disease
Can cause allergic bronchopulmonary aspergillosis
Scedosporium in CF
An unusual isolate
Lolipop canidia
Risk factors for acquisition are not clear
Some strains can remain present for years
Trends in epidemic strands of BCC in CF
BCC outbreaks in Toronto and Canada
Two main markers:
-BCESM -> Burkholderia cepacia Epidemic Strain Marker
- cbLA -> cable-like pil
ET-12 Burkholderia cenocepacia IIA has both BCESM and cbIA markers
ET-12 has been the causative strain of outbreaksa -> not all but some
There have also been epidemic BCC strains which have neither markers
Trends in PA epidemic strains in CF
These are transmissible strains in paediatric and adult CF centres
Atypical PA: They tend to be non-motile, non-pigmented and multi-resistant
Correct ID important in infection control and therapeutics
Molecular ID and typing is the gold standard
Trends in TB
TB is the leading cause of death from a single infectious agent
In 2020 there were 10 million cases and 1.4 million deaths
8.2% of cases were in people with HIV -> 50% of this in southern africa i.e. 4% of worldwide TB in southern Africa
500,000 people developed rifampicin-resistant TB (RR-TB)
78% of (RR-TB?) people had multidrug-resistant TB (MDR-TB)
3.3% of new TB cases and 17.7% of previously treated cases had MDR/RR-TB
Covid-19 pandemic threatens to reverse recent progress in reducing the global burden of TB
