1st August 2023

Bacterial Infections

Infection	Clinical features	Management
Tuberculosis (mycobacterium tuberculosis)	Areas with high rates of TB also often have high rates of HIV, and immunosuppression caused by HIV predisposes to TB infection. HIV infection often also causes the reactivation of latent TB. TB in immunocompromised individuals can present in atypical ways – such as more prominent hilar lymphadenopathy and the absence of the characteristic cavitating lesions. Extrapulmonary manifestations are also more common. Mantoux testing and sputum sampling are less reliable in immunosuppressed individuals – culturing for acid-fast bacilli with Ziehl-Neelsen stain remains the best diagnostic test.	Standard management with anti-TB drugs of rifampicin, isoniazid, pyrazinamide and ethambutol, although extended courses may be given. Potential for interaction with antiretroviral drugs – each case should be considered individually. Paradoxical inflammatory reactions, or immune reconstitution inflammatory syndrome (IRIS), can be seen in patients with TB who are started on antiretrovirals. Presents as an acute exacerbation of TB symptoms. Managed by withholding ART temporarily and continuing anti-TB drugs.
Mycobacterium avium complex (MAC)	An atypical mycobacterium which presents only when patients are heavily immunosuppressed (i.e. CD4 count of less than 50). MAC causes fever, malaise, weight loss and sweats and is associated with anaemia and diarrhoea. Diagnosed through culturing blood, lymph nodes and bone marrow samples.	Generally resistant to anti-TB drugs. Most common treatment is a combination of ethambutol, rifabutin and clarithromycin.
Pneumonia (including Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, and Moraxella catarrh,alis amongst other species)	Pneumonia is a common infection in immunocompromised individuals – should be considered in any respiratory illness, especially associated with cough, fever and systemic upset. Illness is more likely to become disseminated in immunocompromised individuals. Should also consider more atypical causes of pneumonia and common community-acquired pathogens.	Antimicrobials, as per local guidance.

Infection

Clinical features

Management

Tuberculosis (mycobacterium tuberculosis)

Areas with high rates of TB also often have high rates of HIV, and immunosuppression caused by HIV predisposes to TB infection. HIV infection often also causes the reactivation of latent TB.

TB in immunocompromised individuals can present in atypical ways – such as more prominent hilar lymphadenopathy and the absence of the characteristic cavitating lesions. Extrapulmonary manifestations are also more common.

Mantoux testing and sputum sampling are less reliable in immunosuppressed individuals – culturing for acid-fast bacilli with Ziehl-Neelsen stain remains the best diagnostic test.

Standard management with anti-TB drugs of rifampicin, isoniazid, pyrazinamide and ethambutol, although extended courses may be given.

Potential for interaction with antiretroviral drugs – each case should be considered individually.

Paradoxical inflammatory reactions, or immune reconstitution inflammatory syndrome (IRIS), can be seen in patients with TB who are started on antiretrovirals. Presents as an acute exacerbation of TB symptoms. Managed by withholding ART temporarily and continuing anti-TB drugs.

Mycobacterium avium complex (MAC)

An atypical mycobacterium which presents only when patients are heavily immunosuppressed (i.e. CD4 count of less than 50).

MAC causes fever, malaise, weight loss and sweats and is associated with anaemia and diarrhoea.

Diagnosed through culturing blood, lymph nodes and bone marrow samples.

Generally resistant to anti-TB drugs.

Most common treatment is a combination of ethambutol, rifabutin and clarithromycin.

Pneumonia (including Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, and Moraxella catarrh,alis amongst other species)

Pneumonia is a common infection in immunocompromised individuals – should be considered in any respiratory illness, especially associated with cough, fever and systemic upset.

Illness is more likely to become disseminated in immunocompromised individuals.

Should also consider more atypical causes of pneumonia and common community-acquired pathogens.

Antimicrobials, as per local guidance.

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