High incidence of atypical mycobacteriosis in African HIV-infected adults with low CD4 cell counts: a 6-year cohort study in Côte d'Ivoire

The Manifesto of Pharmacoenosis: Merging HIV Pharmacology into Pathocoenosis and Syndemics in Developing Countries

Pathocoenosis and syndemics theories have emerged in the last decades meeting the frequent need of better understanding interconnections and reciprocal influences that coexistent communicable and non-communicable diseases play in a specific population. Nevertheless, the attention to pharmacokinetic and pharmacodynamics interactions of co-administered drugs for co-present diseases is to date limitedly paid to alert against detrimental pharmacological combos. Low and middle-income countries are plagued by the highest burden of HIV, tuberculosis, malaria, and helminthiasis, and they are experiencing an alarming rise in non-communicable disorders. In these settings, co-infections and comorbidities are common, but no tailored prescribing nor clinical trials are used to assess and exploit existing opportunities for the simultaneous and potentially synergistic treatment of intertwined diseases. Pharmacoenosis is the set of interactions that take place within a host as well as within a population due to the compresence of two or more diseases and their respective treatments. This framework should pilot integrated health programmes and routine clinical practice to face drug–drug interaction issues, avoiding negative co-administrations but also exploiting potential favourable ones to make the best out of the worst situations; still, to date, guiding data on the latter possibility is limited. Therefore, in this narrative review, we have briefly described both detrimental and favourable physiopathological interactions between HIV and other common co-occurring pathologies (malaria, tuberculosis, helminths, and cardiovascular disorders), and we have presented examples of advantageous potential pharmacological interactions among the drugs prescribed for these diseases from a pharmacokinetics, pharmacodynamics, and pharmacogenetics standpoint.

Mycobacterium avium: an overview

Mycobacterium avium is an environmental microorganism found in soil and water sources worldwide. It is the most prevalent species of nontuberculous mycobacteria that causes infectious diseases, especially in immunocompromised individuals. This review discusses and highlights key topics about M. avium, such as epidemiology, pathogenicity, glycopeptidolipids, laboratory identification, genotyping, antimicrobial therapy and antimicrobial resistance. Additionally, the main comorbidities associated with M. avium infection are discussed.

Tuberculosis and non-tuberculous mycobacteria among HIV-infected individuals in Ghana

OBJECTIVES

To assess the prevalence and clinical importance of previously unrecognised tuberculosis (TB) and isolation of non-tuberculous mycobacteria (NTM) among HIV-infected individuals in a teaching hospital in Ghana.

METHODS

Intensified mycobacterial case finding was conducted among HIV-positive individuals before initiation of antiretroviral therapy (ART). Data were collected on socio-demographic characteristics, medical history and TB-related signs and symptoms, and participants were followed for six months to determine treatment and vital status. Two sputum samples were obtained and examined for mycobacteria with smear microscopy, culture and Xpert MTB/RIF assay. NTM species were identified with the GenoType Mycobacterium CM/AS or sequence analysis of 16S rRNA gene.

RESULTS

Of 473 participants, 60 (12.7%) had confirmed pulmonary TB, and 38 (8.0%) had positive cultures for NTM. Mycobacterium avium complex was identified in 9/38 (23.7%) of NTM isolates. Participants with NTM isolated were more likely to have CD4 cell count< 100 cells/μL (aOR 2.37; 95% CI: 1.10-5.14), BMI<18.5kg/m(2) (aOR 2.51; 95% CI: 1.15-5.51) and fever ≥2 weeks (aOR 2.76; 95% CI: 1.27-6.03) at baseline than participants with no mycobacteria. By six months, 76 (16.1%) participants had died; 20 (33.3%) with confirmed TB and 9 (23.7%) with NTM-positive culture. Mortality at six months was independently associated with TB diagnosis at enrolment (aHR 1.97; 95% CI 1.09-3.59), but not with NTM isolation after controlling for age, sex, CD4 cell count, BMI, prolonged fever and ART initiation.

CONCLUSIONS

Intensified mycobacterial screening of HIV-infected individuals revealed a high burden of unrecognised pulmonary TB before ART initiation, which increased risk of death within six months. NTM were frequently isolated and associated with signs of poor clinical status but not with increased mortality.

Non-tuberculous mycobacteria (NTM) in Zambia: prevalence, clinical, radiological and microbiological characteristics

Background

Non-tuberculous mycobacteria (NTM) infection is an emerging health problem. We present here the Zambia-specific national level data of prevalence, symptomatic, radiological and microbiological characteristics of NTM, using results from a national Tuberculosis (TB) prevalence survey.

Methods

This was a cross-sectional study of the prevalence of NTM among adults aged 15 years and above, who were participants in a national TB prevalence survey. Participants who had either an abnormal chest x-ray or were symptomatic were considered presumptive TB cases and submitted sputum for smear and culture analysis. HIV testing was performed on an opt-out basis. Symptomatic NTM prevalence was estimated from individual level analysis.

Results

Of the 6,123 individuals with presumptive TB, 923 (15.1 %) were found to have NTM, 13 (0.2 %) were MTB/NTM co-infected and 338 (5.5 %) were contaminated (indeterminate). The prevalence of symptomatic NTM was found to be 1,477/100,000 [95 % CI 1010–1943]. Smear positivity, history of cough or chest pain and HIV positivity were risk factors for NTM.

Conclusion

This first study to estimate the national prevalence of NTM in Zambia indicates that the burden is high. The NTM occurrence in Zambia constitutes both a public health and ethical issue requiring action from health managers.

Trends in nontuberculous mycobacterial disease in hospitalized subjects in Spain (1997-2010) according to HIV infection

OBJECTIVES

The aim of the study was to estimate the incidence of nontuberculous mycobacterial (NTM) disease and the rate of NTM disease-related mortality and to analyse trends in these variables according to HIV infection.

METHODS

We performed a retrospective study for the period 1997-2010 using data from the Minimum Basic Data Set (MBDS) provided by the Spanish Ministry of Health. The exposure variables were: (i) HIV infection (HIV positive versus HIV negative); (ii) calendar period in relation to widespread use of combination antiretroviral therapy (cART) [1997-1999 (early cART period), 2000-2003 (middle cART period) and 2004-2010 (late cART period)]. The outcome variables were (i) new NTM disease diagnosis and (ii) mortality.

RESULTS

A total of 3729 cases of incident NTM disease were collected in MBDS, 1795 in the HIV-negative group and 1934 in the HIV-positive group, among whom 602 deaths occurred, 223 in the HIV-negative group and 379 in the HIV-positive group. The incidence of NTM disease and the rate of NTM disease-related mortality were 1000-fold higher in the HIV-positive group than in the HIV-negative group. Regarding the incidence of NTM disease, in the HIV-negative group the incidence increased from 2.91 to 3.97 events per 1,000,000 patient-years from 1997-1999 to 2004-2010 (P < 0.001), while in the HIV-positive group the incidence decreased from 2.29 to 0.71 events per 1000 patient-years from 1997-1999 to 2004-2010 (P < 0.001). Regarding mortality, in the HIV-negative group mortality increased from 2.63 to 4.26 events per 10,000,000 patient-years from 1997-1999 to 2000-2003 (P = 0.059), and then the rate stabilized at around 3.87 events per 10,000,000 patient-years in 2004-2010 (P = 0.128), while in the HIV-positive group mortality decreased from 4.28 to 1.39 events per 10,000 patient-years from 1997-1999 to 2004-2010 (P < 0.001).

CONCLUSIONS

HIV infection was associated with a higher NTM disease incidence and higher NTM disease-related mortality than in the general population, but these rates decreased in the HIV-positive group from 1997-1999 to 2004-2010, whereas the NTM disease incidence increased in the HIV-negative group.

Urine lipoarabinomannan point-of-care testing in patients affected by pulmonary nontuberculous mycobacteria--experiences from the Danish Cystic Fibrosis cohort study

Background

The urine lipoarabinomannan (LAM) strip test has been suggested as a new point-of-care test for active tuberculosis (TB) among human immunodeficiency virus (HIV) infected individuals. It has been questioned if infections with nontuberculous mycobacteria (NTM) affect assay specificity. We set forth to investigate if the test detects LAM in urine from a Danish cystic fibrosis (CF) population characterized by a high NTM prevalence and negligible TB exposure.

Method

Patients followed at the Copenhagen CF Center were comprehensively screened for pulmonary NTM infection between May 2012 and December 2013. Urine samples were tested for LAM using the 2013 Determine™ TB LAM Ag strip test.

Results

Three-hundred and six patients had a total of 3,322 respiratory samples cultured for NTM and 198 had urine collected (65%). A total of 23/198 (12%) had active pulmonary NTM infection. None had active TB. The TB-LAM test had an overall positive rate of 2.5% applying a grade 2 cut-point as positivity threshold, increasing to 10.6% (21/198) if a grade 1 cut-point was applied. Among patients with NTM infection 2/23 (8.7%) had a positive LAM test result at the grade 2 cut-point and 9/23 (39.1%) at the grade 1 cut -point. Test specificity for NTM diagnosis was 98.3% and 93.1 for grade 2 and 1 cut-point respectively.

Conclusions

This is the first study to assess urine LAM detection in patients with confirmed NTM infection. The study demonstrated low cross-reactivity due to NTM infection when using the recommended grade 2 cut-point as positivity threshold. This is reassuring in regards to interpretation of the LAM test for TB diagnosis in a TB prevalent setting. The test was not found suitable for NTM detection among patients with CF.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0655-4) contains supplementary material, which is available to authorized users.

Trends in overall opportunistic illnesses, Pneumocystis carinii pneumonia, cerebral toxoplasmosis and Mycobacterium avium complex incidence rates over the 30 years of the HIV epidemic: a systematic review

BACKGROUND

The natural history of HIV infection has changed dramatically after the introduction of highly active antiretroviral therapy. Currently, opportunistic illnesses still represent a major cause of death and hospitalization in this population. In this study, we review the trends in opportunistic illnesses incidence rates and compare the results observed in high-income settings with that for low/middle-income settings, with special attention given to studies from Brazil.

METHODS

We systematically searched Pubmed, Web of Science, Lilacs and Google scholar for publications on HIV associated opportunistic illness. Studies reporting rates based on person-time for all opportunistic illnesses and/or the three opportunistic infections of interest, namely, Pneumocystis carinii pneumonia, cerebral toxoplasmosis, and Mycobacterium avium complex were included.

RESULTS

Significant reductions in the incidence rates were demonstrated for opportunistic illnesses overall and also for the specific opportunistic infections included in the present study, both in high and low/middle-income settings. Out of the 37 studies included in the present review, almost 70% were from high-income settings. All the studies conducted in low/middle-income settings were single center studies and four were from Brazil. We found no study from Brazil reporting annual incidence rates of opportunistic illnesses.

CONCLUSIONS

Opportunistic illnesses remain an important public health problem. To better guide health policies in low/middle-income settings, multicenter cohort studies should be encouraged. Studies from Brazil are urgently needed to assess the current burden of opportunistic illnesses in our population and to support the planning of HIV/AIDS health care services organization.

Prevalence of non-tuberculous mycobacterial infections among tuberculosis suspects in Nigeria

Background

Nigeria is ranked in the top five countries for tuberculosis deaths worldwide. This study investigated the mycobacterial agents associated with presumptive clinical pulmonary tuberculosis (TB) in Nigeria and evaluated the pattern and frequency of mycobacterial infections over twelve calendar months period.

Methods

Sputum samples from 1,603 consecutive new cases with presumptive diagnosis of TB were collected from August 2010 to July 2011. All sputum samples were incubated for detection of mycobacterial growth and those with positive acid fast bacilli (AFB) growth were tested to detect mycobacterium tuberculosis (MTB) complex and characterized to differentiate between MTB complex species. Cultures suggestive of Non-tuberculous mycobacterial infections (NTM) were sub-cultured and characterized.

Results

Of the 1,603 patients screened, 444 (28%) culture-positive cases of pulmonary tuberculosis were identified. Of these, 375 (85%) were due to strains of MTB complex (354 cases of M. tuberculosis, 20 M. africanum and one case of M. bovis) and 69 (15%) were due to infection with NTM. In contrast to the MTB complex cases, the NTM cases were more likely to have been diagnosed during the calendar months of the Harmattan dust season (OR = 2.34, 1.28–4.29; p = 0.01), and aged older than 35 years (OR = 2.77, 1.52–5.02, p = 0.0007), but less likely to have AFB identified on their sputum smear (OR = 0.06, 0.02–0.14, p<0.0001). Among those with NTM infection, cases 35 years or younger were more likely to have co-infection with HIV (3.76, 1.72–8.22; p = 0.0009) compared to those older than 35 years.

Interpretation

The high proportion of younger patients with clinical pulmonary TB due to NTM and co-infection with HIV and the likely role of the seasonal dust exposure in the occurrence of the disease, present novel public health challenges for prevention and treatment.

Demonstration of cord formation by rough Mycobacterium abscessus variants: implications for the clinical microbiology laboratory

In low-income countries some infections caused by nontuberculous mycobacteria are misdiagnosed as multidrug-resistant tuberculosis. In most of these settings the observation of microscopic cords is the only technique used to identify Mycobacterium tuberculosis in the laboratory. In this article we definitively demonstrate that Mycobacterium abscessus, an emerging pulmonary pathogen, also forms microscopic cords.

Infection due to a novel mycobacterium, mimicking multidrug-resistant Mycobacterium tuberculosis

The treatment of multidrug-resistant tuberculosis (TB) requires the use, for long periods, of drugs liable to cause significant side effects. In the case of misdiagnosis of multidrug-resistant TB, the patient is exposed to toxic substances without any benefit. In low-income countries, where the microbiological diagnosis of TB relies on microscopy only, the misdiagnosis of multidrug-resistant TB is very frequent in patients persistently smear-positive despite anti-TB treatment, with the possibility of an infection due to non-tuberculous mycobacteria (NTM) being neglected. The isolation of a mycobacterium from the sputum of a Somali patient apparently confirmed the previous diagnosis of cavitary pulmonary disease. Preliminary investigations led, at first, to the strain being identified as multidrug-resistant Mycobacterium tuberculosis, with findings fully in agreement with the patient's history, which was characterized by repeated interruptions of anti-TB treatment. Thorough phenotypic and genotypic analyses led subsequently to the recognition that the strain was a previously unreported non-tuberculous mycobacterium. The patient, who was unresponsive to the anti-TB treatment, dramatically improved once a drug combination active against NTM was used. A major objective of this article is to alert the medical community to the risk, present also in settings in which sophisticated diagnostic techniques are used, that a cavitary infection due to NTM, and consequently not responding to the anti-TB standard regimen, will be mistaken for multidrug-resistant TB.

Weight gain at 3 months of antiretroviral therapy is strongly associated with survival: evidence from two developing countries

BACKGROUND

In developing countries, access to laboratory tests remains limited, and the use of simple tools such as weight to monitor HIV-infected patients treated with antiretroviral therapy should be evaluated.

METHODS

Cohort study of 2451 Cambodian and 2618 Kenyan adults who initiated antiretroviral therapy between 2001 and 2007. The prognostic value of weight gain at 3 months of antiretroviral therapy on 3-6 months mortality, and at 6 months on 6-12 months mortality, was investigated using Poisson regression.

RESULTS

Mortality rates [95% confidence interval (CI)] between 3 and 6 months of antiretroviral therapy were 9.9 (7.6-12.7) and 13.5 (11.0-16.7) per 100 person-years in Cambodia and Kenya, respectively. At 3 months, among patients with initial body mass index less than or equal to 18.5 kg/m (43% of the study population), mortality rate ratios (95% CI) were 6.3 (3.0-13.1) and 3.4 (1.4-8.3) for those with weight gain less than or equal to 5 and 5-10%, respectively, compared with those with weight gain of more than 10%. At 6 months, weight gain was also predictive of subsequent mortality: mortality rate ratio (95% CI) was 7.3 (4.0-13.3) for those with weight gain less than or equal to 5% compared with those with weight gain of more than 10%.

CONCLUSION

Weight gain at 3 months is strongly associated with survival. Poor compliance or undiagnosed opportunistic infections should be investigated in patients with initial body mass index less than or equal to 18.5 and achieving weight gain less than or equal to 10%.

Mortality and causes of death in adults receiving highly active antiretroviral therapy in Senegal: a 7-year cohort study

OBJECTIVES

To evaluate survival and investigate causes of death among HIV-1 infected adults receiving HAART in Senegal.

DESIGN

An observational prospective cohort.

METHODS

Mortality was assessed in the first patients enrolled between August 1998 and April 2002 in the Senegalese antiretroviral drug access initiative. First-line regimen combined two nucleoside reverse transcriptase inhibitors and either a non-nucleoside reverse transcriptase inhibitor or a protease inhibitor. The most likely causes of death were ascertained through medical records or post-mortem interviews (verbal autopsy).

RESULTS

Four hundred and four patients (54.7% women) were enrolled in the study and were followed for a median of 46 months (interquartile range: 32-57 months) after HAART initiation. At baseline, 5% were antiretroviral therapy (ART) non-naive, 39 and 55% were respectively at CDC stage B and C, median age, CD4 cell count and viral load were 37 years, 128 cells/microl and 5.2 log cp/ml, respectively. Ninety-three patients died during follow-up and the overall incidence rate of death was 6.3/100 person-years [95% confidence interval (CI), 5.2-7.7]. During the first year after HAART initiation, 47 patients died and seven were lost to follow-up, yielding to a probability of dying of 11.7% (95% CI, 8.9-15.3%). The death rate, which was highest during the first year after HAART initiation, decreased with time yielding a cumulative probability of dying of 17.4% (95% CI, 13.9-21.5%) and 24.6% (95% CI, 20.4-29.4%) at 2 and 5 years. Causes of death were ascertained in 76 deaths. Mycobacterial infections, neurotropic infections and septicaemia were the most frequent likely causes of death.

CONCLUSIONS

This study underlines the early mortality pattern after HAART initiation and highlights the leading role of mycobacterial infections in the causes of death.