Community-based care vs. centralised hospitalisation for MDR-TB patients, KwaZulu-Natal, South Africa

SETTING

KwaZulu-Natal, South Africa, a predominantly rural province with a high burden of tuberculosis (TB), multidrug-resistant TB (MDR-TB) and human immunodeficiency virus (HIV) infection.

OBJECTIVE

To determine the most effective care model by comparing MDR-TB treatment outcomes at community-based sites with traditional care at a central, specialised hospital.

DESIGN

A non-randomised observational prospective cohort study comparing community-based and centralised care. Patients at community-based sites were closer to home and had easier access to care, and home-based care was available from treatment initiation.

RESULTS

Four community-based sites treated 736 patients, while 813 were treated at the centralised hospital (total = 1549 patients). Overall, 75% were HIV co-infected (community: 76% vs. hospitalised: 73%, P = 0.45) and 86% received antiretroviral therapy (community: 91% vs. hospitalised: 82%, P = 0.22). On multivariate analysis, MDR-TB patients were more likely to have a successful treatment outcome if they were treated at a community-based site (adjusted OR 1.43, P = 0.01). However, outcomes at the four community-based sites were heterogeneous, with Site 1 demonstrating that home-based care was associated with an increased treatment success of 72% compared with success rates of 52-60% at the other three sites.

CONCLUSION

Community-based care for MDR-TB patients was more effective than care in a central, specialised hospital. Home-based care further increased treatment success.

The treatment journey of a patient with multidrug-resistant tuberculosis in South Africa: is it patient-centred?

To improve the treatment of patients co-infected with multidrug-resistant tuberculosis (MDR-TB) and the human immunodeficiency virus, we measured the relationship between treatment outcomes and hospital performance at four decentralised MDR-TB sites in South Africa. We describe hospital performance from the patient's perspective by the use of a graphic that visually represents a patient's treatment journey. The graphic was used to report study findings to study sites and as a catalyst for a quality improvement process.

Comparing early treatment outcomes of MDR-TB in decentralised and centralised settings in KwaZulu-Natal, South Africa

SETTING

In KwaZulu-Natal, South Africa, a setting endemic for tuberculosis (TB) and the human immunodeficiency virus (HIV), prolonged hospitalisation for the treatment of the growing number of multidrug-resistant TB (MDR-TB) patients is neither possible nor effective.

OBJECTIVE

To compare early treatment outcomes in patients with MDR-TB with and without HIV co-infection at four decentralised rural sites with a central urban referral hospital.

DESIGN

This is an operational, prospective cohort study of patients between 1 July 2008 and 30 November 2009, where culture conversion, time to culture conversion, survival and predictors of these outcomes were analysed.

RESULTS

Of 860 patients with MDR-TB, 419 were at the decentralised sites and 441 at the central hospital. Overall, 71% were HIV co-infected. In the 17-month study period, there was a higher proportion of culture conversion at the decentralised sites compared with the centralised hospital (54% vs. 24%, P < 0.001, OR 3.76, 95%CI 2.81-5.03). The median time to treatment initiation was significantly shorter at the decentralised sites compared with the centralised hospital (72 vs. 93 days, P < 0.001). There was no significant difference in survival following treatment initiation.

CONCLUSION

In this study, early treatment outcomes suggest that decentralised care for MDR-TB patients is superior to that in a centralised setting.

Tuberculosis retreatment category predicts resistance in hospitalized retreatment patients in a high HIV prevalence area

SETTING

Rates of multidrug-resistant tuberculosis (MDR-TB) are currently as high as 7.7% in retreatment cases in KwaZulu-Natal, South Africa. MDR-TB prevalence is known to be high in patients categorized as treatment failures. Recent reports have questioned the effectiveness of the World Health Organization (WHO) Category II regimen in retreatment TB cases.

OBJECTIVE

To determine whether treatment category predicts susceptibility patterns and outcomes in a hospitalized population of retreatment TB cases.

DESIGN

Retrospective cohort of 197 pulmonary retreatment cases.

RESULTS

Retreatment cases treated with the standard retreatment regimen had a high in-hospital mortality (19.8%), or poor outcome (26.4%) and a high rate of MDR-TB (16.2%). The 'treatment failure' category predicted resistance, with 57.1% of patients exhibiting any resistance compared to other treatment categories (P = 0.02); 53.8% of patients with any resistance experienced poor outcomes, compared to 16.6% of pan-susceptible cases (P = 0.02). There was a trend towards poor outcome in the treatment failure category (42.9%, P = 0.13).

CONCLUSION

The retreatment category 'treatment failure' is associated with a high prevalence of resistance in an area of high human immunodeficiency virus (HIV) prevalence. The 'treatment failure' category should be used to identify patients who may benefit from alternative regimens using directed, intensified therapy or second-line agents instead of the current standard retreatment regimen.

The A17L gene product of vaccinia virus is exposed on the surface of IMV

The p21 membrane protein of vaccinia virus (VV), encoded by the A17L gene, has been reported to localize on the inner of the two membranes of the intracellular mature virus (IMV). It has also been shown that p21 acts as a membrane anchor for the externally located fusion protein p14 (A27L gene). Since p14 is located on the surface of IMVs, it is hard to envision that p21 should be located only on the inner membrane. Our results from (i) immunoelectron microscopy, (ii) biotinylation, and (iii) protease treatment of purified IMVs showed that the N-terminus of p21 is exposed on the surface of virus particles, while the C-terminus is embedded in the membrane. Mono-specific antibodies to the N-terminus of p21 neutralize infection of VV while antibodies to the C-terminal domain do not. We suggest that p21 molecules are located both in the inner and in the outer membrane of IMV.

Minimal exclusion of plasma membrane proteins during retroviral envelope formation

The retrovirus forms its envelope by budding at the plasma membrane (PM). This process is primarily driven by its cytoplasmic core-precursor protein, Gag, as shown by the efficient formation of virus-like Gag particles in the absence of its envelope protein, Env. Most interestingly, several studies have demonstrated incorporation of various PM proteins into retrovirus, but the underlying mechanism of this phenomenon has remained elusive. We have purified Moloney murine leukemia virus Gag particles by sedimentation in an iodixanol gradient and donor PMs by flotation in a sucrose gradient and compared their protein compositions at equal lipid basis. We found that most PM proteins are present at similar density in both membranes. The inclusion of PM proteins was unaffected by incorporation of Env protein into the envelope of the Gag particles and whether these were produced at high or low level in the cells. These findings indicate that most PM proteins become incorporated into the retrovirus envelope without significant sorting. This feature of retrovirus assembly should be considered when studying retrovirus functions and developing retrovirus vectors.

Localization of actin in Moloney murine leukemia virus by immunoelectron microscopy

Immunoelectron microscopy was used to detect actin in wild-type (wt) Moloney murine leukemia virus (MoMuLV) and in virus-like particles (VLP) produced by recombinant Semliki Forest virus expressing only the MoMuLV gag polyprotein. Gold immunolabeling revealed the presence of actin on the surface of delipidized VLP and delipidized wt virus particles. Statistical evaluation of the number of colloidal gold particles per VLP revealed a large range of values and a prevalence of VLP with small numbers of gold particles. Labeling for actin was lost after prolonged treatment of VLP with 1% Nonidet-P40, high-pH buffer, or gelsolin. Gold immunolabeling with antibodies to gag proteins p15 (MA) and p12 and p30 (CA) was abundant and was not affected by treatment of VLP or wt virus with 1% Nonidet or gelsolin. VLP treated with a mixture of detergent and aldehyde fixatives showed more uniform and consistent labeling for actin than without fixatives. Negative staining or heavy metal shadowing revealed a globular surface of delipidized VLP. Stereomicrographs of gold-immunolabeled VLP showed that p15gag and p12gag were associated with the globular projections. Delipidized VLP were also well labeled with antibody to p30gag, which indicated that the gag shell permitted access of antibodies to p30gag and was therefore not a closely packed structure. Labeling for actin-binding proteins moesin and ezrin was negative in both the wt virus and the VLP. The absence of Gaussian distribution of actin in the sample of VLP suggests that actin is not a structural protein and its presence in MuLV virus particles may be fortuitous. This, however, does not rule out any possible role of actin in transport, assembly, budding, or release of virus particles, events which take place in the cytoplasm or at the plasma membrane. The site of actin in VLP is discussed in relation to the present knowledge of the molecular organization of the MuLV gag shell.