Diagnosis Of Opportunistic Infections- Bacteria
Those bacteria infecting cell mediated immunity include:-
- Listeria monocytogenes
- Legionella pneumophila
- Atypical mycobacterium
- Norcardia ssp.
Listeria monocytogenes are gram positive diptheroid like bacteria, non-sporing bacillus. It infect:-
· the newborns whose mothers have been infected.
· Cancer patients.
· Patients on corticosteroids (immunosuppressive treatment).
Specimen required include:-
· Lochia (discharge from the mother – HVS)
This specimen should be stored in the fridge at 40C. It grows well on BAP and majority of strains are:-
- B – haemolytic
- Small gram positive roods sometimes coccobacillis hence confuse with streptococcus
- Do catalase test to differentiate it from streptococcus.
- They are motile in room temperature (tumbling motility).
- D o sugar fermentation test to differentiate it from Erysipellothrix rhusiopaathiae which is non-motile and micro-aerophilic
It causes lung infection and is treated with Erythromycin. They are gram negative pleomorphic bacilli. Needs special media made of charcoal blood agar (Iron, selective antibiotic , micro-aerophilic condition – 5-10% CO2 at 37oC . After it has grown subject the colonies to indirect fluorescent antibody (IFAT) using U.V light. In Serology, you need to pair sera acute and convalescent sera. Diagnosis of the bacteria is long hence doctors diagnose it clinically.
Patients have prolonged fever. Specimens required include sputum, urine, tissue, biopsy and CSF.