Species identification and drug susceptibility testing of non-tuberculous mycobacteria by Line Probe Assay in Lambaréné, Gabon-a cross-sectional study

BACKGROUND

Non-tuberculous mycobacteria (NTM) are a group of bacteria that cause rare lung infections and are increasingly recognized as causative agents of opportunistic and device-associated infections in humans. In Gabon, there is a lack of data on NTM species identification and drug susceptibility. The aim of this study was to identify the frequency of NTM species and their genotypic susceptibility pattern to commonly used antibiotics for NTM infections in Gabon.

METHODS

A cross-sectional study was conducted at the CERMEL TB laboratory from January 2020 to December 2022, NTM subspecies identification and drug susceptibility testing to macrolides and aminoglycosides were performed using the genotype NTM-DR kit.

RESULTS

The study found that out of 524 culture-positive specimens, 146 (28%) were NTM, with the predominant group being Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABC). All MAC isolates were fully susceptible to macrolides and aminoglycosides, while five MABC isolates carried mutations indicative of reduced susceptibility to macrolide and aminoglycoside drugs.

CONCLUSIONS

These findings suggest that clinicians may use macrolides and aminoglycosides to manage NTM infections caused by MAC, but further investigation is required to determine MABC drug susceptibility.

Non-communicable disease co-morbidity and associated factors in tuberculosis patients: A cross-sectional study in Gabon

BACKGROUND

There are only limited data from resource-limited settings available on the prevalence of non-communicable diseases and associated risk factors of tuberculosis patients. This study investigated non-communicable disease co-morbidity in tuberculosis patients from Moyen Ogooué Province, Gabon.

METHODS

All patients aged 18 years or older consulting for tuberculosis (TB) symptoms in Gabon's Moyen Ogooué province and neighbouring provinces from November 2018 to November 2020 were screened for diabetes mellitus, hypertension, and risk factors thereof (obesity, dyslipidaemia, smoking and alcohol consumption). Logistic regression was performed to identify factors associated with TB-diabetes and TB-hypertension co-morbidities.

FINDINGS

Of 583 patients included, 227 (39%) were diagnosed with tuberculosis. In tuberculosis-confirmed patients, the prevalences of hypertension and diabetes were 16·3% and 12·8%, respectively. The prevalence of diabetes was twice as high in tuberculosis patients compared to non-tuberculosis patients. Factors independently associated with hypertension-tuberculosis co-morbidity were age >55 years (aOR=8·5, 95% CI 2·43, 32·6), age 45-54 years (aOR=4.9, 95%CI 1.3-19.8), and moderate alcohol consumption (aOR=2·4; 95% CI 1·02- 5·9), respectively. For diabetes-tuberculosis co-morbidity, age >55 years was positively (aOR=9·13; 95% CI 2·4-39·15), and moderate alcohol consumption inversely associated (aOR=0·26, 95% CI 0·08- 0·73). One-hundred-and-four (46%) of the tuberculosis patients had at least either dyslipidaemia, hypertension, diabetes, or obesity with a majority of newly-diagnosed hypertension and diabetes.

INTERPRETATION

Integration of screening of non-communicable diseases and their risk factors during TB assessment for early diagnosis, treatment initiation and chronic care management for better health outcomes should be implemented in all tuberculosis healthcare facilities.

FUNDING

This study was supported by WHO AFRO/TDR/EDCTP (2019/893,805) and Deutsches Zentrum für Infektiologie (DZIF/ TTU 02.812).

Non-tuberculous mycobacteria isolation from presumptive tuberculosis patients in Lambaréné, Gabon

OBJECTIVE

The prevalence of clinical cases of pulmonary non-tuberculous mycobacteria (NTM) is increasing worldwide. The aim of this study was to determine the proportion and the NTM species isolated from presumptive tuberculosis patients in Lambaréné, Gabon.

METHOD

From January 2018 to December 2020, sputum samples from presumptive TB patients were analysed at the tuberculosis reference laboratory of the Centre de Recherches Médicales de Lambaréné. Two sputum samples were collected per patient, and culture was performed using Bactec MGIT 960. The GenoType Mycobacterium CM/AS was used for NTM isolates confirmation and species differentiation.

RESULTS

Among 1363 sputum samples analysed, 285 (20.9%) were Auramin acid fast bacilli (AFB) smear-positive. NTM were isolated in 137/1363 (10%) of the samples. The most prevalent NTM species was Mycobacterium intracellulare (n=74; 54%).

CONCLUSION

These results show the presence of NTM among presumptive TB patients in Gabon, which could potentially complicate TB diagnosis. This presents a new public health challenge, and emphasises the need to consider NTM in planning the prevention and management of tuberculosis control.

Epidemiological, Mycobacteriological, and Clinical Characteristics of Smoking Pulmonary Tuberculosis Patients, in Lambaréné, Gabon: A Cross-Sectional Study

Gabon carries a high burden of both tuberculosis (TB) and smoking. This study examines the disease characteristics of smoking pulmonary TB patients in Lambaréné. We interviewed adult pulmonary TB patients in Lambaréné, between March 2016 and April 2019. Clinical and biological patient characteristics were collected. Bivariate and logistic regression analyses were performed to assess factors associated with smoking. The mean age of patients included was 31 years (±13). The proportion of smokers in our study was 30% (89/295). Smoking was significantly associated with patient-related diagnostic delay (adjusted odds ratio [AOR] = 8.18; 95% CI = 3.67-19.56), a higher number of pulmonary TB signs and symptoms (AOR = 2.74; 95% CI = 1.18-6.73), and a higher sputum mycobacterial load (AOR = 3.18; 95% CI = 1.33-8.11). The prevalence of smoking among TB patients is high, and leading to aggravated disease as compared with controls. Our study findings suggest that smoking patients should be regularly screened for TB, to reduce diagnostic delay and TB transmission within community. Smoking cessation activities should be included in the national TB control program in Gabon.

Effects of Unripe Musa Paradisiaca on the Histochemistry of the Testis and Testosterone Levels in Adult Albino Rats

This study was aimed at determining the effects of the unripe fruit of Musa paradisiaca on the testis andtestosterone levels in male Wistar rats. The animals were grouped into three, comprising a control, and 2 treatment groupsadministered with different doses (500 mg/kg and 1000 mg/kg) daily of the fruit flour over 28 days. Histochemical evaluationof the testes was done using Haematoxylin and Eosin, Periodic acid Schiff's (PAS) and Feulgen staining techniques, whilethe serum and homogenised testicular tissue were evaluated for testosterone levels using Accu-Bind ELISA Kit. The testisof the treated groups showed more rapidly dividing cells and more population of sperm cells compared to the control group,and also showed more positivity for Feulgen staining and PAS reaction. Both serum and testicular testosterone levels werehowever reduced. Serum testosterone was significantly lowered in the animals given the low dose (0.67 ± 0.03 ng/ml),compared to those given high dose (0.85 ± 0.02 ng/ml) and the control animals (1.88 ± 0.15 ng/ml) (p < 0.05). Changes intesticular testosterone were not statistically significant. The study suggests that M. paradisiaca fruit has reproductiveenhancing potential when consumed moderately, but this benefit may not be related to testosterone levels.

Enhanced laboratory capacity development: a boost for effective tuberculosis control in resource-limited settings

Both routine and research tuberculosis (TB) laboratory capacity urgently need to be expanded in large parts of Sub-Saharan Africa. In 2009, the Centre de Recherches Médicales de Lambaréné (CERMEL) took a strategic decision to expand its activities by building TB laboratory capacity to address research questions and to improve routine diagnostic and treatment capacity. Over the past 7 years, a standard laboratory has been developed that is contributing significantly to TB diagnosis, treatment, and control in Gabon; training has also been provided for TB research staff in Central Africa. CERMEL has a cordial relationship with the Gabon National TB Control Programme (PNLT), which has culminated in a successful Global Fund joint application. This endeavour is considered a model for similar developments needed in areas of high TB prevalence and where TB control remains poor to date.

Pattern of prostate cancer among a Nigerian population: A study in a single tertiary care centre

BACKGROUND

Prostate cancer has become a global health challenge because of its rising morbidity and mortality in males. It is the second cause of cancer death following lung cancer in men. It is rare under the age of 40 and its incidence has been shown to increase exponentially with age. Previously, Prostate cancer was thought to be a disease rare in blacks owing to the fact that not so much was known of the disease.

AIMS AND OBJECTIVES

The objective of the study was to review the prevalence, pattern of presentation and clinic-pathologic findings of prostate cancer in the Department of Radiotherapy, Lagos University Teaching Hospital (LUTH), between January 2001 to December 2010 in comparison to previous and recent studies globally.

METHODOLOGY

Data collection for all patients histologically diagnosed with Prostate cancer at the Department of Radiotherapy, LUTH, from 1st of January 2001 to 31st of December 2010 was done.

RESULTS

A total of 144 cases with histologically confirmed Prostate cancer seen during the ten year study were analysed. The highest frequency was seen in the year 2010 with 34 cases. The age range was 41 to 81years with a mean of 66.19 ±7.30years.Adenocarcinoma was the commonest histological type with 98.6%.9(6.3%) patients had a positive family history of prostate cancer out of which 3(33.3%) had their brother affected the malignancy. 51(35.4%) patients presented with stage IV disease.18(12.5%) patients had a Gleason's score of 6,10(6.9%) patients had a Gleason's score of 7 and 2(1.4%) patients had a Gleason's score of 10. The most common presenting complaints were bone pains seen in 51(35.4%) patients, frequent night urine and difficulty with micturition seen in 50(34.7%) and 42(29.2%) patients respectively.

CONCLUSION

This study showed that prostate cancer is not as rare as it used to be. Reasons attributed to its rarity then were lack of awareness, poor screening facilities and poor diagnosing technique.

β-Hemolytic streptococcal throat carriage and tonsillopharyngitis: a cross-sectional prevalence study in Gabon, Central Africa

BACKGROUND

Group A streptococcus (GAS) and possibly other β-hemolytic streptococci (BHS) account for a considerable morbidity and mortality burden in African populations; however, disproportionately little is known about the epidemiology of BHS in sub-Saharan Africa. This study assessed the prevalence of GAS, group G streptococcus (GGS) and group C streptococcus (GCS) carriage and tonsillopharyngitis in a Central African population.

METHODS

A prospective cross-sectional study was performed to assess the prevalence of and risk factors for BHS carrier status and tonsillopharyngitis in children and adults in Gabon.

RESULTS

The overall BHS carrier prevalence was 135/1,005 (13.4%); carrier prevalence of GAS, GGS, and GCS was 58/1,005 (5.8%), 50/1,005 (5.0%), and 32/1,005 (3.2%), respectively. Streptococcal carriage was associated with school and pre-school age (adjusted OR 2.65, 95% CI 1.62-4.36, p = 0.0001 and 1.90, 95% CI 1.14-3.17, p = 0.0141, respectively). Participants residing in urban areas were less likely carriers (OR 0.52, p = 0.0001). The point-prevalence of BHS-positive tonsillopharyngitis was 1.0% (9/1,014) and 15.0% (6/40) in school children with sore throat.

CONCLUSIONS

Non-GAS exceeded GAS throat carriage and tonsillopharyngitis suggesting a yet underestimated role of non-GAS streptococci in BHS diseases.

Transmission of Staphylococcus aureus between mothers and infants in an African setting

Staphylococcus aureus colonization is a risk factor for invasive disease. There is a need to understand S. aureus colonization in infancy as the burden of S. aureus infections in infants is high. We aimed to investigate the transmission of S. aureus between mothers and their newborns during the first year after delivery in an African setting. In a longitudinal cohort study, colonization of Gabonese mother-infant pairs was assessed at delivery and after 1, 9 and 12 months. Swabs were taken from mothers (nares, mammillae) and infants (nares and throat). Isolates were characterized and risk factors for colonization were assessed using a standardized questionnaire. We recruited 311 mothers and 318 infants including seven sets of twins. Maternal and infant colonization rates declined synchronously following a peak after 1 month at 40% (mothers) and 42% (infants). Maternal colonization was a risk factor for S. aureus carriage in infants. Based on spa typing, direct mother-to-infant transmission was evident in 5.6%. Of all methicillin-resistant isolates (n = 9), 44.4% were related to the USA300 clone; 56.7% (n = 261) of all S. aureus carried Panton-Valentine leukocidin encoding genes. Direct mother-to-infant transmission was rare and cannot explain the increase of carriage in infants within the first month. A transmission from external sources is likely and challenges the S. aureus infection control in newborns and infants in an African setting. The detection of USA300-related MRSA fuels the concern about the spread of this clone in Central Africa.

Beneficial effects of low dose Musa paradisiaca on the semen quality of male Wistar rats

Background:

This study aimed at determining the effects of administration of mature green fruits of Musa paradisiaca on the semen quality of adult male Wistar rats.

Materials and Methods:

The animals used for the study were grouped into three: the control group, given 2 ml of double distilled water, a low dose group given 500 mg/kg/day and a high dose group given 1000 mg/kg/day of the plantain fruits, which was made into flour, and dissolved in 2 ml of double distilled water for easy oral administration.

Results:

Significant increment in the semen parameters was noticed in animals that received a lower dose of the plantain flour, but those animals who received the high dose had marked and very significant reduction in sperm cell concentration and percentage of morphologically normal spermatozoa.

Conclusion:

Musa paradisiaca should be consumed in moderate quantities in order to derive its beneficial effects of enhancing male reproductive functions.

Carriage of encapsulated bacteria in Gabonese children with sickle cell anaemia

Sickle cell anaemia (SCA) is a haemoglobin disorder that alters the deformability of erythrocytes through abnormal polymerization of haemoglobin. Children with SCA have an increased risk of infections with encapsulated bacteria. To guide the antibiotic prophylaxis and vaccinations in children with SCA in Gabon, we characterized Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae from children with and without SCA. We performed a cross-sectional study and compared nasal and pharyngeal S. pneumoniae, Staph. aureus and H. influenzae isolates from SCA children (n = 73) with comparators matched for age, residence and sex (n = 143) in a matched-comparison analysis. The resistance pattern and capsular type were identified for each isolate. The total carriage rate for S. pneumoniae, Staph. aureus and H. influenzae was 13.8%, 46.7% and 12.5%, respectively, and did not differ between groups (p >0.05). The mean number of days under antibiotic treatment in the past year was higher in children with SCA than in controls (penicillin: 70.1 vs 0.1 days, p 0.00002). The total non-susceptibility rate was 30% for oral and parenteral (meningitis) penicillin in S. pneumoniae, resistance rates were 1.6% for oxacillin in Staph. aureus and 14.8% for ampicillin in H. influenzae. Susceptibility to antibiotic agents and distribution of capsular types did not differ significantly between both groups. In conclusion, carriage and resistance rates are similar in children with and without SCA. Our data provide the basis to guide empiric therapy of invasive diseases caused by S. pneumoniae, Staph. aureus and H. influenza in children in Gabon.

Highly divergent Staphylococcus aureus isolates from African non-human primates

Staphylococcus aureus is a bacterium that colonizes and infects both humans and animals. As little is known about the phenotypic and molecular characteristics of S. aureus from wild animals in sub-Saharan Africa, the objective of the study was to characterize S. aureus isolates from wildlife and to analyse if they differed from those found among humans. The resistance to penicillin was low in S. aureus isolates from non-human primates (2.9%). Phylogenetic analysis based on the concatenated sequences from multilocus sequence typing revealed two highly divergent groups of isolates. One group was predominated by S. aureus that belonged to known human-related STs (ST1, ST9 and ST601) and mainly derived from great apes. A second clade comprised isolates with novel STs. These isolates were different from classical human S. aureus strains and mainly derived from monkeys. Our findings provide the basis for future studies addressing the inter- and intra-species transmission of S. aureus in Africa.

Maternal HIV-1 and HIV-2 infection and child survival in The Gambia

OBJECTIVE

To compare the survival of children born to HIV-1 or HIV-2 seropositive mothers with that of children born to HIV-seronegative mothers and to evaluate risk factors for mortality.

DESIGN

Physician-blinded prospective study.

METHODS

One hundred and one HIV-1-seropositive, 243 HIV-2-seropositive pregnant women, and 468 HIV-seronegative women (control group) matched by age, parity, and health centre, were followed up in a study of mother-to-child transmission of HIV. Mothers and children were seen at 2 and 6 months of age and subsequently followed at 3-monthly intervals up to 18 months of age. HIV infection in children was diagnosed by polymerase chain reaction at 2, 9 or 18 months and by antibody assays at 18 months.

RESULTS

Fifteen per cent of children born to HIV-1-infected mothers died compared with 7% of children born to HIV-2-infected mothers [hazard ratio, 2.3; 95% confidence interval (CI), 1.1-4.7; P = 0.02], and 6% of HIV-seronegative mothers (hazard ratio, 2.6; 95% CI, 1.4-5.0; P = 0.003). Six of the 17 children known to be HIV-1 infected died compared with none among the eight HIV-2-infected children (P = 0.13). High proviral load in the babies, high antenatal maternal RNA plasma viral load, and maternal death increased child mortality significantly.

CONCLUSIONS

More children born to HIV-1-infected mothers died in comparison with those born to HIV-2-infected mothers or to mothers from the control group. This effect was due to excess death in HIV-1-infected infants which was associated with a high viral load in the affected mother and child.

Plasma RNA viral load predicts the rate of CD4 T cell decline and death in HIV-2-infected patients in West Africa

OBJECTIVE

To examine whether the levels of plasma RNA and DNA provirus predict the rate of CD4 cell decline and patient death.

DESIGN

Retrospective analysis of HIV-2 cohort subjects.

METHODS

Fifty-two subjects were recruited between January 1991 and December 1992. HIV-2 RNA levels in plasma and DNA levels in peripheral blood mononuclear cells (PBMC) were measured using in-house quantitative PCR assays. The annual rate of CD4 cell decline was calculated using the least-squares method. The survival data on 31 December 1997 were used.

RESULTS

The mean percentage of CD4 cells at baseline was 30.7 (SD, 9.5). In a linear regression model, the annual rate of CD4 cell decline was 1.76 CD4% faster for every increase in one log10 RNA copies/ml [95% confidence interval (CI), 0.81-2.7; P = 0.0006; r = 0.46; n = 52] and 1.76 CD4% faster for every increase in log10 DNA copies/10(5) PBMC (95% CI 0.46-3.1; P = 0.01; r = 0.33; n = 42). In a multiple linear regression model, RNA load was related to CD4 decline independently of DNA load (P = 0.02). The overall mortality rate was 7.29/100 person-years. In a Cox regression model, the hazard rate increased by 2.12 for each log10 increase in RNA load (95% CI, 1.3-3.5; P = 0.0023) but only by 1.09 for each log10 increase in DNA load (95% CI, 0.64-1.87; P = 0.8).

CONCLUSION

This longitudinal study shows for the first time that a baseline HIV-2 RNA load predicts the rate of disease progression. HIV-2-infected patients with a high viral load may need to be treated as vigorously as HIV-1 patients.