Using a component of the Escherichia coli protein degradation machinery, we have established a system to regulate protein stability in mycobacteria. A protein tag derived from the E. coli SsrA degradation signal did not affect several reporter proteins in wild-type Mycobacterium smegmatis or Mycobacterium tuberculosis. Expression of the adaptor protein SspB, which recognizes this modified tag and helps deliver tagged proteins to the protease ClpXP, strongly decreased the activities and protein levels of different reporters. This inactivation did not occur when the function of ClpX was inhibited. Using this system, we constructed a conditional M. smegmatis knockdown mutant in which addition of anhydrotetracycline (atc) caused depletion of the beta subunit of RNA polymerase, RpoB. The impact of atc on this mutant was dose-dependent. Very low amounts of atc did not prevent growth but increased sensitivity to an antibiotic that inactivates RpoB. Intermediate amounts of RpoB knockdown resulted in bacteriostasis and a more substantial depletion led to a decrease in viability by up to 99%. These studies identify SspB-mediated proteolysis as an efficient approach to conditionally inactivate essential proteins in mycobacteria. They further demonstrate that depletion of RpoB by ∼93% is sufficient to cause death of M. smegmatis.
Clients in comprehensive HIV care coordination for persons with evident barriers to care showed substantial and consistent improvement in short-term outcomes.
Lower mental health functioning, unstable housing, and drug use can complicate HIV clinical management. Merging programmatic and surveillance data, we examined characteristics and outcomes for HIV Care Coordination clients enrolled between December 2009 and March 2013. For clients diagnosed over 12 months before enrollment, we calculated post- versus pre-enrollment relative risks for short-term (12-month) care engagement and viral suppression. Both outcomes significantly improved in all subgroups, including those with lower mental health functioning, unstable housing, or hard drug use. Analyses further stratified within barrier-affected groups showed a tendency toward greater improvement when that barrier was reduced during the follow-up year.
Background:
To assess long-term effectiveness of an intensive and comprehensive Ryan White Part A-funded HIV Care Coordination Program (CCP) recruiting people living with HIV (PLWH) with a history of suboptimal HIV care outcomes.
Methods:
We merged programmatic data on CCP clients with surveillance data on all adults diagnosed with HIV. Using propensity score matching, we identified a contemporaneous, non-CCP exposed comparison group. Durable viral suppression (DVS) was defined as regular VL monitoring and all VLs ≤200 copies/mL in months 13–36 of follow-up.
Results:
Ninety percent of the combined cohort (N=12,414) had ≥1 VL≤200 during the follow-up period (December 1, 2009 to March 31, 2016), and nearly all had routine VL monitoring, but only 36.8% had DVS. While DVS did not differ overall (relative risk[RR]: 0.99, 95%CI: 0.95–1.03), CCP clients without any VL suppression in the 12 months pre-enrollment showed higher DVS versus ‘usual care’ recipients (21.3% versus 18.4%; RR: 1.16, 95%CI: 1.04–1.29).
Conclusions:
Enrollment in an intensive intervention modestly improved DVS among those unsuppressed prior to CCP enrollment. This program shows promise for meeting treatment-as-prevention goals and advancing progress along the HIV care continuum, if people without evidence of VLS are prioritized for CCP enrollment over those with recent evidence of VLS. Low overall DVS (<40%) levels underscore a need for focused adherence-maintenance interventions, in a context of high treatment access.
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