MATHEMATICAL ANALYSIS OF THE ROLE OF DETECTION RATE IN THE DYNAMICAL SPREAD OF HIV-TB CO-INFECTION

Human Immunodeficiency Virus (HIV) co-existing with Tuberculosis (TB) in individuals remains a major global health challenges, with an estimated 1.4 million patients worldwide. These two diseases are enormous public health burden, and unfortunately, not much has been done in terms of modeling the dynamics of HIV-TB co-infection at a population level. We formulated new fifteen (15) compartmental models to gain more insight into the effect of treatment and detection of infected undetected individuals on the dynamical spread of HIV- TB co-infection. Sub models of HIV and TB only were considered first, followed by the full HIV-TB co-infection model. Existence and uniqueness of HIV and TB only model were analyzed quantitatively, and we shown that HIV model only and TB only model have solutions, moreover, the solutions are unique. Stability of HIV model only, TB model only and full model of HIV-TB co-infection were analyzed for the existence of the disease free and endemic equilibrium points. Basic reproduction number () was analyzed, using next generation matrix method (NGM), and it has been shown that the disease free equilibrium point is locally asymptotically stable whenever  and unstable whenever this threshold exceeds unity. i.e., Numerical simulation was carried out by maple software using differential transformation method, to show the effect of  treatment and detection of infected undetected individuals on the dynamical spread of HIV-TB co-infection. Significantly, all the results obtained from this research show the importance of treatment and detection of infected undetected individuals on the dynamical spread of HIV-TB co-infection. Detection rate of infected undetected individuals reduce the spread of HIV-TB co-infections

In vitro assessment of antibiotic-resistance reversal of a methanol extract from Rosa canina L.

The crude methanol extract of Rosa canina (RC) fruit was tested against multidrug-resistant (MDR) bacterial strains, including methicillin-resistant Staphylococcus aureus SA1199B, EMRSA16 and XU212 harbouring NorA, PBP2a and TetK resistance mechanisms, respectively, as well as S. aureus ATCC25923, a standard antimicrobial susceptible laboratory strain. The inhibition of the conjugal transfer of plasmid PKM101 and TP114 by the RC extract was also evaluated. The RC extract demonstrated a mild to poor antibacterial activity against the panel of bacteria having MIC values ranging from 256 to >512 μg/mL but strongly potentiated tetracycline activity (64-fold) against XU212, a tetracycline-effluxing and resistant strain. Furthermore, the extract showed moderate capacity to inhibit the conjugal transfer of TP114 and PKM101; transfer frequencies were between 40% and 45%. Cytotoxicity analysis of the RC extract against HepG2 cells line showed the IC50 > 500 mg/L and, thus, was considered non-toxic towards human cells. Phytochemical characterisation of the extracts was performed by the assessment of total phenolic content (RC: 60.86 mg TAE/g) and HPLC fingerprints with five main peaks at 360 nm. The results from this study provide new mechanistic evidence justifying, at least in part, the traditional use of this extract. However, the inhibition of bacterial plasmid conjugation opens the possibility of combination therapies to overcome antibiotic resistance

Antibacterial and norfloxacin potentiation activities of Ocimum americanum L. against methicillin resistant Staphylococcus aureus

Staphylococcus species are among the most common resistant bacteria associated with the major cause of human ailments. The crude methanol extract from Ocimum americanum (OA) leaf was tested alone or in combination with norfloxacin (NOR) against strains of Staphylococcus aureus using the broth microdilution assay. The cytotoxicity of the OA extract was also evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) reagent assay on a HepG2 hepatocarcinomal cell line. While the plant extract exhibited a mild to poor antibacterial activity against our panel of bacteria, the antibiotic activity of norfloxacin at one-quarter MIC was enhanced by 2–4 fold in the presence of one-half MIC of OA extract against SA-1199B that over expresses the NorA efflux pump and MRSA-274829. These positive interactions were confirmed using a time-killing test; the combination therapy remarkably reduced the bacterial count of SA1199B and MRSA274829 ranging from a 6.0–4.2-log10-CFU/mL, after 24 h incubation. The OA extract strongly depleted DPPH* (IC50: 146.5 μg/mL), LOI (152 μg/mL), PGI (47.6 μg/mL) and FRAP (122.75 μmolFe(II)/g) possibly due to its richness in phenolic compounds. Furthermore, the OA extract showed a non-toxic effect on the HepG2 cells having an IC50 value of 378.0 μg/mL. These findings therefore support the folkloric use of Ocimum americanum at least in part for the treatment of infectious and free radical stress-related diseases