Significance of Glutamate Racemase for the Viability and Cell Wall Integrity of Streptococcus iniae.

Streptococcus iniae is a pathogenic and zoonotic bacterium responsible for human diseases and mortality of many fish species. Recently, this bacterium has demonstrated an increasing trend for antibiotics resistance, which has warranted a search for new approaches to tackle its infection. Glutamate racemase (MurI) is a ubiquitous enzyme of the peptidoglycan synthesis pathway that plays an important role in the cell wall integrity maintenance; however, the significance of this enzyme differs in different species. In this study, we knocked out the MurI gene in S. iniae in order to elucidate the role of glutamate racemase in maintaining cell wall integrity in this bacterial species. We also cloned, expressed, and purified MurI and determined its biochemical characteristics. Biochemical analysis revealed that the MurI gene in S. iniae encodes a functional enzyme with a molecular weight of 30 kDa, temperature optimum at 35°C, and pH optimum at 8.5. Metal ions, such as Cu2+, Mn2+, Co2+ and Zn2+, inhibited the enzyme activity. MurI was found to be essential for the viability and cell wall integrity of S. iniae. The optimal growth of the MurI-deficient S. iniae mutant can be achieved only by adding a high concentration of D-glutamate to the medium. Membrane permeability assay of the mutant showed an increasing extent of the cell wall damage with time upon D-glutamate starvation. Moreover, the mutant lost its virulence when incubated in fish blood. Our results demonstrated that the MurI knockout leads to the generation of S. iniae auxotroph with damaged cell walls.

Patients who present late to HIV care and associated risk factors in Nigeria.

OBJECTIVES: Our objectives were to assess trends in late presentation and advanced HIV disease (AHD) and determine associated risk factors. METHODS: We conducted a retrospective cohort analysis of patients who had received care and treatment at the AIDS Prevention Initiative Nigeria Plus (APIN)/Harvard School of Public Health-President's Emergency Plan for AIDS Relief (PEPFAR) programme at the Jos University Teaching Hospital, Jos, Nigeria from 2005 to 2010. We used the European Consensus Definition to assess trends in late presentation (CD4 count < 350 cells/µL or AIDS-defining illness) and AHD (CD4 count < 200 cells/µL or AIDS-defining illness) and evaluated associated risk factors using logistic regression methods. RESULTS: Among 14,487 eligible patients, 12,401 (85.6%) were late presenters and 9127 (63.0%) presented with AHD. Late presentation decreased from 88.9% in 2005 to 80.1% in 2010 (P < 0.001). Similarly, AHD decreased from 67.8% in 2005 to 53.6% in 2010 (P < 0.001). In logistic regression models adjusting for sociodemographic and biological variables, male sex [adjusted odds ratio (aOR) = 1.80; 95% confidence interval (CI) 1.60-2.04], older age (aOR = 1.37; 95% CI 1.22-1.54), civil service employment (aOR = 1.48; 95% CI 1.00-2.21), referral from out-patient (aOR = 2.18; 95% CI 1.53-3.08) and in-patient (aOR = 1.55; 95% CI 1.11-2.17) services, and hepatitis B virus (aOR = 1.43; 95% CI 1.26-1.63) and hepatitis C virus (aOR = 1.18; 95% CI 1.02-1.37) coinfections were associated with late presentation. Predictors of AHD were male sex (aOR = 1.67; 95% CI 1.54-1.82), older age (aOR = 1.26; 95% CI 1.16-1.36), unemployment (aOR = 1.34; 95% CI 1.00-1.79), referral from out-patient (aOR = 2.40; 95% CI 1.84-3.14) and in-patient (aOR = 1.97; 95% CI 1.51-2.57) services and hepatitis B virus coinfection (aOR = 1.30; 95% CI 1.19-1.42). CONCLUSIONS: Efforts to reduce the proportion of patients who first seek care at late stages of disease are needed. The identified risk factors should be utilized in formulating targeted public health interventions to improve early diagnosis and presentation for HIV care.

Presentation and survival of patients with AIDS-related Kaposi's sarcoma in Jos, Nigeria.

AIDS-related Kaposi's sarcoma (AIDS-KS) remains a significant cause of morbidity and mortality. We describe the pattern of presentation and survival in Jos, Nigeria. We identified 48 HIV-positive patients with AIDS-KS and matched them for age and sex with an equal number of HIV-positive patients without AIDS-KS. We compared their clinical, immunological, virological characteristics and survival. They were similar in age and body mass index profile but patients with AIDS-KS had more tuberculosis co-infection (P, 0.02), lower median CD4 count (P, 0.003) and higher mortality (P, 0.002). Surprisingly, patients with AIDS-KS had lower levels of median viral load (29,347 copies/mL) compared with controls (80,533 copies/mL). We recommend specific AIDS-KS therapy in addition to highly active antiretroviral therapy in order to improve survival.