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 American Journal of  
Medical Science and Innovation (AJMSI)

Epidemiological Profile and Diagnosis of  Pulmonary Tuberculosis in the Commune of  
Ntoum, Northwest Gabon  

Bourdettes Meye1*, Hilaire Moundounga Kenguele2, Strédice Maguinga Guitouka3, Kevin Alame Emane4, Joseph Privat Ondo1, 
Louis Clément Obame Engonga¹

Volume 4 Issue 2, Year 2025
ISSN: 2836-8509 (Online)

DOI: https://doi.org/10.54536/ajmsi.v4i2.5191
https://journals.e-palli.com/home/index.php/ajmsi

Article Information ABSTRACT

Received: April 24, 2025

Accepted: May 31, 2025

Published: August 05, 2025

Pulmonary tuberculosis remains a major public health problem in Gabon. The aim of  this 
study was to determine the epidemiological profile of  pulmonary tuberculosis in patients 
from the commune of  Ntoum and its surrounding area. This was a cross-sectional study 
from January 2024 to March 2025. The study enrolled patients who attended the Tuberculosis 
Diagnostic and Treatment Centre (CDT) of  the Ntoum Departmental Hospital (Northwest 
Gabon) for consultation or therapeutic follow-up. A total of  146 patients were enrolled. 
Males predominated (54.2%), with a sex ratio of  1.21. The mean age of  the study population 
was 34.94 years, with an age range 8-77. Ntoum 6 and Mebba neighbourhoods had the 
highest rate of  tuberculosis patients (8.6% each) in the Ntoum commune. TB/HIV co-
infection accounted for 2.2% of  patients, with a therapeutic success rate of  77.6%. The 
mycobacterial strains detected by GeneXpert were all sensitive to Rifampicin. In order to 
achieve the WHO’s goal of  eliminating tuberculosis by 2030, tuberculosis diagnosis and 
treatment centers in most of  Gabon’s health regions play an important role. Despite the 
relatively high rate of  therapeutic success observed, efforts are still needed in the area 
of  case management. The diagnosis of  HIV in all tuberculosis patients, or the molecular 
diagnosis of  tuberculosis in all HIV-positive patients, must be spontaneous. In addition, 
tuberculosis patients must be monitored clinically and biologically on a regular basis. If  
these recommendations are put into practice, the number of  cures will increase nationwide.

Keywords
CDT, Gabon, Ntoum, Prevalence, 
Tuberculosis

1 Department of  Biochemistry, Laboratory of  Research in Biochemistry (LAREBIO), University of  Sciences and Techniques of
  Masuku (USTM) Franceville, & Medical Analysis Laboratory of  Ntoum Departmental Hospital (NDH), Gabon
2 Department of  Biology, Laboratory of  Molecular and Cellular Biology (LABMC), University of  Science and Technology of
  Masuku (USTM), Franceville, Gabon
3 National Tuberculosis Control Program (NTCP), Libreville, Gabon
4 National Public Health Laboratory (NPHL), Libreville, Gabon
* Corresponding author’s e-mail: meyebourdettes@yahoo.fr

INTRODUCTION   
Tuberculosis, which is both preventable and curable, is 
an infectious, contagious disease that mainly affects the 
lungs (Abdelmalek et al., 2013). It is transmitted mainly 
by air from a sick person to a healthy person, through the 
emission of  salivary droplets containing Koch’s bacillus 
(BK) when the patient speaks, coughs, sneezes, si, or 
spits (Swalehe et al., 2024). Worldwide, it represents a 
major public health problem. In 2023, an estimated 10.8 
million people worldwide contracted tuberculosis and 
1.25 million died, including 161,000 co-infected with the 
AIDS virus. HIV infection has accentuated the burden of  
tuberculosis, particularly in sub-Saharan Africa where the 
prevalence of  the disease is high. According to the same 
report, 55% of  tuberculosis sufferers were men, 33% 
women and 12% children and adolescents. Of  all the 
continents, Africa continues to bear the heaviest burden 
(Organization, 2023). To combat this disease effectively, 
early diagnosis of  presumptive cases of  tuberculosis and 
regular monitoring of  tuberculosis patients on treatment 
are important. The absence of  any study of  tuberculosis 
in the commune of  Ntoum lead us to conduct this study. 
The aim was to determine the epidemiological profile of  
pulmonary tuberculosis in the diagnostic and treatment 
center of  the commune of  Ntoum, in north-west Gabon.

MATERIAL AND METHODS
Type, location and period of  study
A cross-sectional study was conducted at the Ntoum 
departmental (ND) hospital over a 15-month period 
from January 2024 to March 2025.  Ntoum, chief  town 
of  this department is located in north -west Gabon in 
the Estuaire province and had 11,813 inhabitants in 
2012 (DGS, 2015). Is a fast-growing town favored by 
the construction of  road infrastructures such as national 
highway n°1, which links the capital Libreville to the 
interior of  the country. The town’s economy is largely 
based on agriculture, fishing and broiler chicken farming.

Sampling 
Over a 15-month period, the ND hospital mycobacteriology 
laboratory performed molecular tuberculosis diagnostics 
on all patients from Gabon’s diagnostic and treatment 
centers (CDT) suspected of  suffering from pulmonary 
tuberculosis.  Control microscopic examinations were 
carried out on bacteriologically confirmed patients 
undergoing treatment to assess the bacillary load at each 
appointment. All results were recorded in the laboratory 
register provided by the TB National Control Program. 
This document was used as the basic tool for collecting 
data from the study sample. The study variables were: 



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Am. J. Med. Sci. Innov. 4(2) 31-35, 2025

sex, age, district of  origin, HIV status and HIV/TB co-
infection.

Inclusion and non-inclusion criteria
All diagnostic and microscopic control results of  patients 
in the laboratory register during the study period were 
eligible for inclusion. Tuberculosis patients registered 
in the laboratory register outside the study period were 
excluded, as were unregistered patients.

Biological material
Sputum was collected in the morning on an empty 
stomach, after rinsing the mouth with water and coughing. 
A volume of  2 ml was sufficient.

Diagnostic methods 
Detection of  DNA from Mycobacteria belonging to 
the Mycobacterium tuberculosis complex, as well as 
mutations in the rpoB gene associated with rifampin 
resistance, was performed on all patients with suspected 
pulmonary tuberculosis using Cepheid’s GeneXpert® 
systems, based on real-time nested PCR. Control of  
the bacillary load in tuberculosis patients undergoing 
antibiotic therapy was carried out using LED (Light 
Emitting Diode) fluorescence microscopy on auramine-
stained smears, based on the acid-fast properties of  bacilli 
linked to the structure of  their cell wall.

Statistical analysis
The data collected were entered into a database using 
Microsoft Excel version 2016. All statistical analyses 
were performed using R software version 1.4.2. The Chi2 
test was used to compare proportions, with a statistical 
significance level set at 5%.

Study approval and ethical considerations 
The study has been approved by the General Management 
of  ND Hospital. All procedures contributing to this 
project comply with the ethical standards of  the 
relevant national and institutional committees on human 
experimentation and with the Declaration of  Helsinki of  
1975, as revised in 2008.

RESULTS AND DISCUSSIONS
Between January 29, 2024 and March 27, 2025, 146 
sputum samples were analyzed at the ND hospital 
mycobacteriology laboratory. The male sex was the most 
represented with 80 cases (54.8%) for a sex ratio equal 
to 1.21.
The 15-29 age group was the largest, with 54 cases (37%). 
The mean age of  the study population was 34.94 years, 
with an age range 8 - 77. 
Examination requests came mostly from the Ntoum 
CDT, with 87 cases (59.6%). The Nkembo and Kango 
CDTs followed with 54 cases (37%) and 2 cases (1.3%) 
respectively.  Other examination requests came from 
three hospitals located in the capital city Libreville namely 
the Omar Bongo Army Hospital (HIAOBO), Melen 

regional hospital (CHREM), and Chinese and Gabonese 
friendship hospital (HASG); each of  them reported one 
case (0.7%).
The largest number of  presumptive pulmonary TB 
patients resided in the town of  Ntoum, with 98 cases 
(67.2%), followed by Libreville and Kango, with 36 
cases (24.6%) and 12 cases (8.2%) respectively. For those 
living in Ntoum, the Ntoum 6 district was home to the 
most presumptive patients, with 21 cases (14.4%). The 
Okolassi, Meyang and Soleil districts followed with 7 
cases (4.8%) each (Table 1).

Table 1: Socio-demographic characteristics of  patients
Sex n %
Male 80 54,8
Female 66 45,2
Age (year)
0 – 14 8 5,5
15 – 29 54 37,0
30 – 44 47 32,2
45 – 59 26 17,8
60 – 74 9 6,1
>75 2 1,4
Health facilities
CDT Ntoum 87 59,6
CDT Nkembo 54 37
CDT Kango 2 1,4
HIAOBO 1 0,7
CHREM 1 0,7
HASG 1 0,7
City of  residence
Libreville 36 24,6
Ntoum 98 67,2
Kango 12 8,2
Ntoum districts
Mebba 5 3,4
Okolassi 7 4,8
Ntoum 6 21 14,4
Nkoltang 5 3,4
Soleil 7 4,8
Essassa 4 2,7
Ayeme 2 1,4
Dame –Oyem 4 2,7
Meyang 7 4,8
Assora 6 4,1
TP 2 1,4
Akoneki 6 4,1
Venez-voir 2 1,4
Nkan 5 3,4
Alarmitang 4 2,7



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Am. J. Med. Sci. Innov. 4(2) 31-35, 2025

PK 27 3 2,0
Cimenterie 2 1,4
PK 11 2 1,4
Dubai 1 0,7
2 lions 1 0,7
Bikele 1 0,7
Bidzango Rails 1 0,7
Total 146 100

Clinical symptoms such as a persistent cough lasting 
more than 2 weeks, whether or not associated with 
cachexia, were the most common motive for physicians 
to request the Xpert MTB/RIF test. Real-time PCR 
was performed on 88 (60.3%) sputum samples. 
Mycobacterium tuberculosis complex DNA was detected 
in 22 samples (25%). All these bacterial strains were 
sensitive to Rifampicin (100%). To assess the efficacy 
of  anti-tuberculosis treatment, microscopic examination 
of  sputum was requested for all tuberculosis patients 
undergoing treatment, in accordance with the national 
protocol for monitoring patients on treatment. A total 
of  58 samples (39.7%) were examined by fluorescence 
optical microscopy (F.O.M.), and more than a fifth 
(22.4%) of  these showed acid-fast bacillus (Table 2).

Table 2: Biological diagnoses of  tuberculosis at ND 
hospital
Diagnostics n %
Xpert MTB/RIF
Mt detected 22                      25
Mt no detected 66                      75 
Total 88                     100
Resistance to Rifampicin
Detected 00                       00
No detected 22                      100
Total 22                      100
Microscopy
Presence of  acid-fast 
bacillus

13                       22,4

Absence of  acid-fast 
bacillus

45                        77,6

Total  58                       100
Legend: Mt = Mycobacterium tuberculosis

Table 3: HIV/Tuberculosis co-infection in patients seen 
at ND HOSPITAL
Variables n %
HIV+/TB+ 3 2,2
HIV+/TB- 11 7,5
HIV-/TB- 12 8,2
 HIV-/TB+ 5 3,4
Inc/TB+ 25 17,1
Inc/TB- 90 61,6
Total 146 100

Legend: TB =Tuberculosis; Inc = Unknown; + = Positive; - = 
Negative.

Distribution of  tuberculosis patients by city of  residence
More than half  the tuberculosis patients (51.4%) lived 
in the town where the study took place (Ntoum). The 
others came from Libreville, the country’s political capital 
(37.1%), followed by the town of  Kango, capital of  the 
Komo-Kango Department (11.5%) (Figure 1).

Figure 1: Distribution of  tuberculosis patients by city of  
residence

Figure 2: Distribution of  tuberculosis patients by Ntoum 
district

As for the Ntoum neighborhoods with the highest number 
of  tuberculosis cases, Mebba and Ntoum 6 were the most 
representative, with 3 cases each (16.8%), followed by 
Meyang and Assora with 2 cases each (11.2%) (Figure 2).

HIV infection was found in 14 people, bringing the rate 
to 9.6% of  HIV cases in the study population. HIV+/
TB+ co-infection was found in 3 patients (2.2%). 
However, a large number of  participants (n=115; 78.7%) 
were unaware of  their HIV status (Table 3).



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Discussion
Of  the 146 sputum samples analyzed, 54.8% came from 
male patients. The sex ratio was one female to 1.21 males. 
These results confirm those of  several studies showing 
a male predominance in patients infected with Koch’s 
bacillus (Tékpa et al., 2019; Kalidou et al., 2021). This is 
probably due to the fact that men have social contacts 
which probably contribute to the burden of  tuberculosis 
disease compared with women (Horton et al., 2020; 
Ozsahin et al., 2011). Consumption of  alcohol, tobacco 
and illicit substances, are other risk factors that increase 
TB susceptibility in men (Narasimhan et al., 2013).
In this study the mean age of  our patients was 34.94 years. 
These results are in line with those found in the Pneumo-
phtisiology departments of  the CHU-RN of  N’Djamena 
and that of  Zinder in Niger, where the mean ages were 
34.1 and 33.5 years respectively (Ngakoutou et al., 2024; 
Hamidou et al., 2024). These results underline the fact 
that tuberculosis strikes with predilection young adults 
because of  their multiple activities and their carelessness 
in the face of  microbial infections.
More than half  the tuberculosis sufferers (51.4%) lived 
in Ntoum (study site), which justifies this high prevalence 
compared with other towns. On the other hand, the city of  
Libreville (Gabon’s political capital) had more tuberculosis 
patients than the city of  Kango (capital of  the Komo-
Kango Department), with 37.1% and 11.5% of  cases 
respectively.  The results of  this comparison confirm the 
idea that tuberculosis is more prevalent in urban than in 
rural areas, as shown by studies carried out at the Zinder 
National Hospital in Niger (Hamidou et al., 2024) and 
those carried out in Morocco, at the Settat Diagnostic 
Center for Tuberculosis and Respiratory Diseases located 
in the Casablanca-Settat region. (Chahboune et al., 2022).
In this study, the prevalence of  TB-HIV co-infection 
was 2.2%. These results are similar to those obtained in 
Niger and the Republic of  Guinea, where prevalences 
were 2.4% and 2.5% respectively (Hamidou et al., 2024; 
Kolamou et al., 2023). HIV infection and tuberculosis 
form a lethal pair, as each of  these diseases accelerates 
the progression of  the other.  HIV-positive people are 16 
times more likely to develop tuberculosis than others, due 
to their compromised immune systems (Organization, 
2023). The discovery of  tuberculosis should be 
systematically followed by an HIV test, which was not the 
case in the Komo-Mondah department, where 17.1% of  
tuberculosis patients did not know their HIV status.
The therapeutic success rate in this study was 77.6%. 
This result is close to that recorded in work carried out 
in Niger (84.2) (Hamidou et al., 2024) and to that found 
in the Pneumo-phtisiology department of  the CHU-RN 
in N’Djamena (83.8%) (Ngakoutou et al., 2024).  This 
therapeutic success rate is the result of  the efficacy of  
the pharmacological regimen adopted by the NTP of  our 
country, Gabon, on Rifampicin-sensitive mycobacterial 
strains.
The WHO recommends GeneXpert as the first-line 
diagnostic test for tuberculosis in all presumptive cases in 

adults and children (Organization, 2013). Among the 88 
samples analyzed, the Mycobarium tuberculosis genome 
was detected 22 times, bringing the prevalence rate to 
25%. Our results are similar to those found in southern 
Ethiopia and Nigeria, where the reported prevalences 
were 26.8% and 22.9% , respectively (Diriba et al., 2022; 
Tahiri et al., 2014). In contrast to our study, the results 
found in the Internal Medicine Department of  the 
National Hospital Donka in Guinea Conakry (31.03%) 
(Wann et al., 2024) and the Central Army Hospital 
Mohamed Seghir Nekkache in Algiers (34, 6%) (Yamouni 
et al., 2024) were higher than in our study, and the results 
found in Addis Ababa (15.1%) (Nugussie et al., 2017) 
and South Africa (13%) (Nicol et al., 2011) were lower 
than ours. These differences in prevalence are probably 
due to the study design, sample size and TB control and 
prevention practices adopted in each country.

CONCLUSION
Tuberculosis diagnosis and treatment centers in Gabon’s 
health regions play an important role in the national 
eradication of  tuberculosis. HIV infection further weakens 
the immune system of  tuberculosis patients. Systematic 
HIV screening is therefore essential for all tuberculosis 
patients, and molecular diagnosis of  tuberculosis must 
also be systematic for all HIV-positive subjects. According 
to the WHO standard, the high presence of  acid-fast 
bacillus in the sputum of  tuberculosis patients in the 
first-line treatment phase, as measured by fluorescence 
microscopy, has a negative impact on therapeutic success. 
Rigorous case follow-up combined with a community-
based anti-tuberculosis treatment strategy will certainly 
increase therapeutic success in Gabon. 

Study limitations
This study was limited by the lack of  data on the HIV 
status of  a large number of  tuberculosis patients (25/115 
cases; 17.1%). This lack of  information may have biased 
the number of  HIV+/TB+ co-infections.

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