Bacterial infections remain the leading killer worldwide which is worsened by the continuous emergence of antibiotic resistance. In particular, antibiotic-resistant Enterobacteriaceae is prevalent and extremely difficult to treat. Reusing existing drugs and rejuvenating the therapeutic potential of existing antibiotics represent an attractive novel strategy. Azidothymidine (AZT) is an antiretroviral drug which is used in combination with other antivirals to prevent and to treat HIV/AIDS. AZT is also active against Gram-negative bacteria but has not been developed for that purpose. Here we investigated in vitro and in vivo efficacy of AZT in combination with colistin against antibiotic-resistant Enterobacteriaceae including extended-spectrum beta-lactamase (ESBL), New Delhi metallo-beta-lactamase 1 (NDM) or the mobilized colistin resistance (mcr-1) producing strains. Minimum inhibitory concentration was determined using the broth microdilution method. The combinatory effect of AZT and colistin was examined using the checkerboard method and time-kill analysis. A murine peritoneal infection model was used to test the therapeutic effect of the combination of AZT and colistin. Fractional inhibitory concentration index from checkerboard assay demonstrated that AZT synergized with colistin against 61% and 87% of ESBL-producing Escherichia coli and Klebsiella pneumoniae, respectively, 100% of NDM-1-producing strains and 92% of mcr-1 producing E. coli Time-kill analysis demonstrated significant synergistic activities when AZT was combined with colistin. In the murine peritoneal infection model, AZT in combination with colistin showed augmented activities of both drugs in the treatment of NDM-1 K. pneumoniae and mcr-1 E. coli infections. AZT and colistin combination poses a potential to be used coherently to treat antibiotic-resistant Enterobacteriaceae infections.

Nucleoside reverse transcriptase inhibitors (NRTI) such as zidovudine (AZT) are constituents of HIV-1 therapy and prevention of mother to child transmission. Prolonged thymidine analogues exposure has been associated with mitochondrial toxicities to heart, liver, and skeletal muscle. We hypothesized that the thymidine analogue AZT might interfere with autophagy in myocytes, a lysosomal degradation pathway implicated in regulation of mitochondrial recycling, cell survival and the pathogenesis of myodegenerative diseases. The impact of AZT and lamivudine (3TC) on C2C12 myocyte autophagy was studied using various methods based on LC3-GFP overexpression or LC3 staining in combination with western blotting, flow cytometry and confocal and electron microscopy. Lysosomal and mitochondrial functions were studied using appropriate staining for lysosomal mass, acidity, cathepsin activity as well as mitochondrial mass and membrane potential in combination with flow cytometry and confocal microscopy. AZT, but not 3TC, exerted a significant dose and time-dependent inhibitory effect on late stages of autophagosome maturation, which was reversible upon mTOR inhibition. Inhibition of late autophagy at therapeutic drug concentrations led to dysfunctional mitochondria accumulation with membrane hyperpolarization and increased ROS generation, and ultimately compromised cell viability. These AZT effects could be readily replicated by pharmacological and genetic inhibition of myocyte autophagy and most importantly rescued by pharmacological stimulation of autophago-lysosomal biogenesis. Our data suggest that the thymidine analogue AZT inhibits autophagy in myocytes, which in turn leads to accumulation of dysfunctional mitochondria with increased ROS generation and compromised cell viability. This novel mechanism could contribute to our understanding of the long-term side effects of antiviral agents.

In the United States and other developed countries, HIV-infected mothers should generally not breastfeed their infants. In countries in which no acceptable, feasible, sustainable and safe replacement feeding is available, World Health Organization guidelines recommend that all women with an HIV infection who are pregnant or breastfeeding should be maintained on antiretroviral therapy for at least the duration of risk for mother-to-child transmission. Mothers should exclusively breastfeed their infants for the first 6 months of life; breastfeeding with complementary feeding should continue through 12 months of life. The first choice regimen for nursing mothers is tenofovir, efavirenz and either lamivudine or emtricitabine. If these drugs are unavailable, alternative regimens include: 1) zidovudine, lamivudine and efavirenz; 2) zidovudine, lamivudine and nevirapine; or 3) tenofovir, nevirapine and either lamivudine or emtricitabine. Exclusively breastfed infants should also receive 6 weeks of prophylaxis with nevirapine.[1][2]

Aim: Zidovudine and tenofovir form the backbone of antiretroviral therapy in Kenya. However, their side-effects may affect the quality of life (QoL) of patients. The aim was to compare the health-related quality of life (HRQoL) of adult patients on tenofovir versus zidovudine based regimens in a referral hospital in Kenya to provide future guidance. Methods: A comparative cross sectional study among 501 adult out-patients on either tenofovir or zidovudine was undertaken in Kenyatta National Hospital between 2015 and 2016. The Medical Outcome Study HIV Health Survey (MOS-HIV) was administered along with other key aspects of treatment. Linear regression analysis was performed to identify determinants of HRQoL. Results: Patients on zidovudine had a higher Physical Health Summary Score (PHSS) and Mental Health Summary Score (MHSS) compared to those on tenofovir. The presence of any symptom of the disease and a stated inability to cope were negatively associated with PHSS, whilst having a regular source of income improved PHSS. Being on tenofovir, symptom of illness [β = -1.24; 95% CI (-2.253, -0.226)], absence of pain [β=0.413; 95% CI (0.152, 0.674)] and patient stated inability to cope with HIV [β = -1.029; 95% CI (-1.441, -0.617)] affected the MHSS. Patients on tenofovir and second line regimens had more signs and symptoms of illness. Conclusion: Participants on zidovudine based regimens showed a better performance across all aspects of HRQoL. These are considerations for the future.

The co-use of conventional drug and herbal medicines may lead to herb-drug interaction via modulation of drug-metabolizing enzymes (DMEs) by herbal constituents. UDP-glucuronosyltransferases (UGTs) catalyzing glucuronidation are the major metabolic enzymes of Phase II DMEs. The in vitro inhibitory effect of several herbal constituents on one of the most important UGT isoforms, UGT2B7, in human liver microsomes (HLM) and rat liver microsomes (RLM) was investigated. Zidovudine (ZDV) was used as the probe substrate to determine UGT2B7 activity. The intrinsic clearance (Vmax/Km) of ZDV in HLM is 1.65 µL/mg/min which is ten times greater than in RLM, which is 0.16 µL/mg/min. Andrographolide, kaempferol-3-rutinoside, mitragynine and zerumbone inhibited ZDV glucuronidation in HLM with IC50 values of 6.18 ± 1.27, 18.56 ± 8.62, 8.11 ± 4.48 and 4.57 ± 0.23 µM, respectively, hence, herb-drug interactions are possible if andrographolide, kaempferol-3-rutinoside, mitragynine and zerumbone are taken together with drugs that are highly metabolized by UGT2B7. Meanwhile, only mitragynine and zerumbone inhibited ZDV glucuronidation in RLM with IC50 values of 51.20 ± 5.95 μM and 8.14 ± 2.12 µM, respectively, indicating a difference between the human and rat microsomal model so caution must be exercised when extrapolating inhibitory metabolic data from rats to humans.

Adverse drug reactions (ADRs) are expected to be associated with an economic drain on the healthcare systems. The study was carried out to determine the occurrence of ADRs reported to NAFDAC Pharmacovigilance from January to June 2015, to illustrate the pattern of organ system affected by ADRs, to assess the completeness of ADR report, to determine the relationship between the occurrence of ADRs with suspect drugs and the use of concomitant drugs as well as to generate possible signals from the reported ADRs. A total number of 921 ADR cases reported from January to June 2015 were analyzed using SPSS version 22. A higher percentage of ADR reports were seen in females (65.5%). The highest percentages of reports (45.6%) were from the age range of 21-40 years, most of the suspected drugs reported had both NAFDAC (50.2%) and batch number identification (65.6%). HIV (56.9%) was the most prevalent indication reported for using the suspected drug; Zidovudine/Lamivudine/Nevirapine combination (16.9%) was reported as the suspected drug with the highest occurrences of ADRs and generalized body itching (6.9%) as the most prevalent ADR. "General disorders" (47.3%) was the most predominant organ system affected by ADRs and Pharmacists were revealed as the highest reporters of ADRs (80.2%). Overall, patients on ARVs should be vigilantly followed up as they are mostly prone to ADRs. Adverse drug reaction reporting systems need to be robust and complete in order to be able to detect new drug alerts, possible signals and improve pharmacovigilance.