AETIOLOGY AND PRESENTATION OF HIV/AIDS-ASSOCIATED PULMONARY INFECTIONS IN PATIENTS PRESENTING FOR BRONCHOSCOPY AT A REFERRAL HOSPITAL IN NORTHERN TANZANIA

Abstract

ABSTRACT
Objectives: To determine the aetiological agents of pulmonary infections in HIV-infected Tanzanians
and to correlate the causative agents with clinical, radiographic features, and mortality.
Design: A prospective study.
Setting: Kilimanjaro Christian Medical Centre (KCMC), Tanzania.
Subjects: Bronchoalveolar lavage fl uid (BAL) were obtained from 120 HIV infected patients with
pulmonary infections. BAL for causative agents was analysed and correlated with clinical and
radiographic features, and one-month outcome.
Results: Causative agents were identifi ed in 71 patients (59.2%) and in 16 of these patients, multiple
agents were found. Common bacteria were identifi ed in 35 patients (29.2%), Mycobacterium
tuberculosis in 28 (23.3%), Human Herpes Virus 8 (HHV8) in 12 (10%), Pneumocystis jiroveci in nine
(7.5%) and fungi in fi ve (4.2%) patients. Median CD4 T cell count of the patients with identifi ed
causes was 47 cells/μl (IQR 14-91) and in the 49 patients with undetermined aetiology was 100 cells/
μl (IQR 36-188; p=0.01). Micronodular chest radiographic lesions were associated with presence
of M. tuberculosis (p=0.002). The one-month mortality was 20 (16.7%). The highest mortality was
associated with HHV8 (41 .7%) and M. tuberculosis (32.1%). Mortality in patients with undetermined
aetiology was 11.3%. No death occurred in patients with PCP.
September 2007 EA S T AF R I C A N ME D I C A L JOURNAL 421
INTRODUCTION
Sub-Saharan Africa is the region of the world most
affected by HIV/AIDS, more than 70% of HIV
infected individuals live in this African sub-continent,
(1) and the HIV pandemic is still increasing. Despite
this, data pertaining to the disease presentation from
this region compared to the developed world are
insuffi cient and require regular updating. The clinical
presentation of HIV/AIDS and the occurrence of
opportunistic infections depend on different factors
such as the presence of endemic diseases, quality
of health services, availability of and access to antiretroviral
treatment, and levels of education of the
population. Pulmonary infections are the leading
causes of morbidity and mortality in HIV-infected
individuals (2,3). A microbiological diagnosis is of
crucial importance in HIV infected patients with
pulmonary infections because of atypical clinical
and radiographic manifestations and high mortality
(4). Because in these settings resources are limited,
treatment is largely empirical, but to be effective,
it should be tailored to locally prevailing causative
organisms. Therefore health facilities equipped with
advanced diagnostic techniques should monitor the
trend of diseases and obtain data on aetiological
pathogens, so that empirical treatment regimens
can be improved.
The aim of this study was to fi nd the aetiological
pathogens of pulmonary infections in HIV/AIDS
patients who presented with features of pulmonary
infection for bronchoscopy.
Furthermore, we correlated the pathogens
identified with clinical and radiographic
presentations, level of immunity, and outcome
after one month.
MATERIALS AND METHODS
At Kilimanjaro Christian Medical Center (KCMC)
in northern Tanzania we enrolled 120 HIV infected
patients aged 18 years and above, who presented
with features of chest infection such as cough
(dry or productive) and/or chest pain, dyspnoea,
fever and chest radiographic abnormalities. These
patients were recruited at the endoscopy unit
where bronchoscopic procedures are done. The
patients were referred by their attending clinicians
for bronchoscopy as part of patient’s management
after failing to establish the causative agent by other
methods and/or following failure to respond to
empirical treatment. Pregnant women and patients
with oxygen saturation less than 90% under 61/mm
of oxygen were excluded from the study.
Bronchoscopy and bronchoalveolar lavage (BAL)
was performed by standard procedure using fl exible
fi beroptic bronchoscope. Briefl y, the bronchoscope
was wedged in one of the heavily involved segmental
bronchi as seen on the chest radiograph. In case of
diffuse lung involvement, the scope was wedged
in one of the segmental bronchi of the right middle
lobe. Then aliquots of 50 ml or less of sterile saline at
body temperature, up to a maximum of 150 ml, were
instilled and at least 40 ml was sucked back into a
sterile container. The sediments of BAL fl uid obtained
by centrifugation at 1500 g for 10 minutes were used
for laboratory tests to identify the aetiological agent
of the chest infection.
For identifi cation of M. tuberculosis, BAL samples
were decontaminated with 4% NaOH, centrifuged
and cultured using in-house made Lowenstein-
Jensen (LJ) solid medium, with a maximum of eight
weeks incubation. Diagnosis of M. tuberculosis was
based on positive culture results showing acid fast
bacilli (AFB) in ZN stain.
Diagnosis of pneumocystis pneumonia (PCP)
was based on identification of Pneumocystis (P)
jiroveci with at least one of the following techniques:
Giemsa stain, Gomori methenamine silver (GMS)
stain or immunofl uorescence test (IFT). Also real
time PCR was performed for detection of P. jiroveci
DNA in the BAL fl uid, using 40 as the cycle threshold
(CT) cut off value (5).
Conventional PCR was used for the diagnosis of
Human herpes virus 8 (HHV8) as described by Chang
and collaborators (6).
Fungi were diagnosed by direct smear and
culture for seven days using Sabouraud dextrose
Conclusion: In this population of severely immunosuppressed HIV-infected patients with
pulmonary infection a variety of causative agents was identifi ed. Micronodular radiographic
lesions were indicative of TB. High mortality was associated with M. tuberculosis or HHV8. No
death occurred in patients with P. jiroveci infection.