Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii

Background. This study was aimed at evaluating the antibacterial activity of the acetone extract of A. mearnsii and its interactions with antibiotics against some resistant bacterial strains. Methods. The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract. Results. The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception of S. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibit Enterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are in μg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity. Conclusion. The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases

Multidrug and vancomycin resistance among clinical isolates of Staphylococcus aureus from different teaching hospitals in Nigeria.

Backgrounds: Staphylococcus aureus has emerged as a major public health concern because of the occurrence of multi-drug resistant strains. This study aimed at investigating the multi-drug and vancomycin resistance profile of S. aureus from different infection sites in some teaching hospitals in Nigeria. Methods: Swabs were collected from different infection sites from out-patients in three teaching hospitals from October 2015 to May, 2016. The antibiotic-susceptibility test was carried out with selected antibiotics usually administered anti-microbials in the treatment of infections in these hospitals. The prevalence of multi-drug and vancomycin resistance strains of S. aureus from clinical samples was determined using disk diffusion and agar dilution methods respectively. Results: The result showed (165)82.5% of the isolates were resistant to 653 antibiotics tested. They were highly resistant to ceftazidime 180(90%), cloxacillin 171(85.6%) and augmentin 167(83.3%), but susceptible to ofloxacin 150(75%), gentamicin 142(71.7%), erythromycin 122(61.1%), ceftriaxone 111(55.6%) and cefuroxime 103(51.7%). All the isolates from the HVS were all multidrug resistant strains. While (56)90.16% were multidrug resistant (MDR) in urine samples, followed by (8)88.89% MDR strains in sputum, (37)88.81% MDR strains in semen, (49)71.64% MDR strains in wounds and (6)60% MDR strains in ear swabs samples. Although (147)73.5% of the isolates were vancomycin susceptible S. aureus (VSSA), (30)15% were vancomycin intermediate resistant S. aureus (VISA) and (89)44.5% of the isolates were considered vancomycin resistant S. aureus (VRSA). Conclusions: The high percentage of the VRSA could have resulted from compromising treatment options and inadequate antimicrobial therapy. The implication, infections caused by VRSA would be difficult to treat with vancomycin and other effective antibiotics of clinical importance. Ensuring proper monitoring of drug administration will, therefore, enhance the legitimate role of vancomycin as an empiric choice for both prophylaxis against and treatment of staphylococcal infections

Bioactive compounds in ethanol extract of Lentinus squarrosulus Mont - a Nigerian medicinal macrofungus

Background: The continuous search for new lead compounds of therapeutic importance has become necessary in the face of treatment failures and multidrug resistance plaguing the world. While many plants and higher fungi are sources of bioactive compounds yet to be fully harnessed, understanding the bioactive components in macrofungus could serve as a lead for investigating its biological activities and medicinal potentials.Materials and Methods: The bioactive compounds in the ethanolic extract of Lentinus Squarrosulus, an edible Nigerian macrofungus, were investigated by Gas Chromatography-Mass Spectrometry (GC-MS) analysis.Results: There were nine bioactive compounds in this edible macrofungus. Of these compounds, 9,12-Octadecanoic acid ethyl ester (37.39%; RT:39.815) was the highest in quantity, followed by Hexadecanoic acid ethyl ester (14.49%; RT:36.550). Other fatty acids, their ethyl esters and other compounds identified included 2-Butenethioic acid,3-(ethylthio)-S-(1-methylethyl) ester (4.51%; RT:15.866), n-Hexadecanoic acid (4.74%; RT:36.034), 9,12-Octadecadienoic acid (Z,Z)- (11.88%; RT:39.429), 9,17-Octadecadienal,(Z)- (5.01%; RT:39.500), ethyl oleate (5.27%; RT:39.898), 3a,6-Methano-3aH-indene,2,3,6,7 tetrahydro (4.04%; RT:48.379), and 9,12-Octadecadienoic acid (Z,Z)-,2 hydroxy-1-(hydroxymethyl) ethyl ester (12.68%; RT:48.682). Some of these compounds have antimicrobial, antioxidant, hepatoprotective, hypocholesterolemic as well as cancer preventive activities amongst others.Conclusion: This study showed the bioactive components of therapeutic potentials in L. squarrosulus while creating a platform for screening, isolating and identifying many bioactive components which may be useful in the treatment of the various ailments, disorders and diseases in the nearest future.Keywords: Bioactive constituents; ethanolic extract; Lentinus squarrosulus; GC-MS analysis; mushroom; macrofung

BIOSYNTHESIS OF SILVER NANOPARTICLES FROM SEAWEED Caulerpa taxifolia AGAINST VECTOR BORNE DISEASE Culex quinquefasciatus

Globally, mosquitoes are transmitting agents for diseases like dengue, malaria, filaria and Japanese encephalitis. In this study, the larvicidal activities of silver nanoparticles (AgNPs) synthesized from seaweed Caulerpa taxifolia extract against the larvae of Culex quinquefasciatus was investigated in vitro. The synthesized AgNPs was further characterized using UV-Vis spectroscopy, FTIR, SEM, XRD, DLS and Zeta potential analysis. From the result, the LC50 value for AgNPs identified was 448.66. The synthesized silver nanoparticles have maximum absorption at 430 nm. The FTIR indicated a specific peak in 3275.11cm-1, 2921.7cm-1 and 1244.28cm-1 range. Scanning electron microscopy resulted in spherical shaped approximately ranging from 1 µm to20 µm in size. The average size distributions of Ag nanoparticles were 72.99 nm and are fairly stable with a zeta potential value of -31.1 mV. The biosynthesis of silver nanoparticles with Caulerpa taxifolia extract provides potential source for the larvicidal activity against mosquito. The present study revealed that green synthesized silver nanoparticles can be used as an eco-friendly means for effective control of vector disease

Pytochemical profile of Aloe ferox Mill. across different regions within South Africa

Background: Aloe ferox is an indigenous medicinal plant that is widely used for its various medicinal and pharmacological properties. Despite the medicinal importance and various applications of the species, it is surprising that little is known about the extent of geographical differences in its major chemical compounds. Also, the correlation between different geographic regions and variations in plant phytochemicals has received less attention. Aim: This study sought to investigate the presence of biologically active compounds in the leaf extracts of A. ferox from different geographical regions across South Africa. Setting: This study was set in different regions within South Africa. Methods: Phytochemical screening was performed qualitatively using established standard procedures involving chemical reagents such as hexane, chloroform and methanol and a series of reactions to determine the presence of phytocompounds of biological importance. Results: The study revealed that A. ferox leaves possess several classes of phytocompounds such as alkaloids, tannins, terpenoids, glycosides, phenolics, flavonoids, saponins and fixed oils and fats across various samples. Mucilage was absent across the samples. Conclusion: The study revealed eight classes of phytochemical compounds present on A. ferox leaves in three different geographic regions, which is consistent with the previous studies; however, further research is needed to enhance the study through qualitative research, gas chromatography–mass spectrometry and high-performance liquid chromatography analyses to validate phytochemical variations and their therapeutic effects. Contribution: This study contributes to the existing knowledge of the therapeutic Aloe genus

Antimicrobial Activity, Phenolic Content, and Cytotoxicity of Medicinal Plant Extracts Used for Treating Dermatological Diseases and Wound Healing in KwaZulu-Natal, South Africa

Medicinal plants used for wound healing and skin diseases are the key to unlocking the doors to combating problematic skin diseases as resistance of pathogens to pharmaceuticals and allopathic management continues to increase. The study aimed at investigating the antimicrobial efficacies, phenolic content and cytotoxicity effects of eleven medicinal plant extracts commonly used for treating skin conditions and wound healing in traditional medicine within KwaZulu-Natal. Eleven plant species were separated into different plant parts (bulbs, roots, leaves) and extracted with different solvents. The extracts were assessed for antimicrobial activity against six Gram-positive and seven Gram-negative bacterial strains and four fungi commonly associated with skin conditions using disc diffusion and microdilution techniques. The aqueous methanolic extracts were screened for phenolic content while cytotoxicity tests were performed on all extracts using the brine shrimp lethality and tetrazolium–based colorimetric (MTT) assays. Extracts from Aloe ferox, A. arborescens and Hypericum aethiopicum were the most active against almost all of the tested bacterial and fungal strains. All plant species exhibited some degree of antimicrobial activity. Total phenolic levels, flavonoids and tannins were also higher for A. ferox, followed by A. arborescens and H. aethiopicum respectively. The cytotoxicity results of all plant extracts were in the range of 90-100% survival after 24 h in the Brine shrimp assay. Extracts considered lethal would demonstrate > 50% shrimp death. The MTT cytotoxicity test yielded LC50 values of > 1 mg/mL on all extracts indicating that they are not cytotoxic. The observed antimicrobial efficacy demonstrated by some plant species and the general lack of cytotoxic effects on all the tested extracts presents some promising and beneficial aspects of these medicinal plant extracts in the treatment of skin diseases and wound healing. The two Aloe species and H. aethiopicum were among the best extracts that exhibited consistently good antimicrobial activity and warrants further investigations and possible isolation of bioactive principles

Vancomycin intermediate resistant Staphylococcus aureus in the nasal cavity of asymptomatic individuals: a potential public health challenge

Background: The potential of transmitting multidrug resistant Staphylococcus aureus from asymptomatic individuals to healthy individuals could constitute a great challenge to antimicrobial therapy. Methods: The antibiograms of the S. aureus from asymptomatic individuals were determined by disk diffusion and agar dilution assay techniques with different antibiotics and vancomycin. Results: Of the 152 S. aureus isolated, (59)38.8% isolates were multi-drug resistant strains. Streptomycin was the most effective and inhibited (135)88.82% of the isolates while ceftazidime inhibited (24)15.8% of the isolates. While (82)54.0% of the isolates inhibited by cefuroxime had resistant colonies within their inhibition zones (Rc) and ofloxacin inhibited (100)65.8% of the isolates without having resistant colonies within the inhibition zones, ceftazidime inhibited (7)4.6% of the isolates with resistant colonies within the inhibition zones. Subjecting the isolates to vancomycin showed that (27)17.8% were resistant to 2 \u3bcg/ml, (43)28.3% were resistant to 4 \u3bcg/ml and (27)17.8% of the isolates were simultaneously resistant to both concentrations of vancomycin. Although (100)65.8% of the isolates had MARindex 650.2, (52)34.2% of the isolates had MARindex 64 0.2 and (65)428% of the isolates were considered multidrug resistant strains. Conclusion: The isolation of multi-drug and vancomycin intermediate resistant strains of S. aureus in high percentage, in this study, presents a great threat to clinicians and general populace. The vancomycin intermediate resistant S. aureus (VISA) in asymptomatic individuals could be a critical concern to the therapeutic dilemma to be added to the presence of multi-drug resistance. A more sustainable therapy must be in place to prevent its dissemination or the outbreak of its infection

BIOACTIVE COMPOUNDS IN ETHANOL EXTRACT OF LENTINUS SQUARROSULUS MONT - A NIGERIAN MEDICINAL MACROFUNGUS

Background: The continuous search for new lead compounds of therapeutic importance has become necessary in the face of treatment failures and multidrug resistance plaguing the world. While many plants and higher fungi are sources of bioactive compounds yet to be fully harnessed, understanding the bioactive components in macrofungus could serve as a lead for investigating its biological activities and medicinal potentials. Materials and Methods: The bioactive compounds in the ethanolic extract of Lentinus Squarrosulus, an edible Nigerian macrofungus, were investigated by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Results: There were nine bioactive compounds in this edible macrofungus. Of these compounds, 9,12-Octadecanoic acid ethyl ester (37.39%; RT:39.815) was the highest in quantity, followed by Hexadecanoic acid ethyl ester (14.49%; RT:36.550). Other fatty acids, their ethyl esters and other compounds identified included 2-Butenethioic acid,3-(ethylthio)-S-(1-methylethyl) ester (4.51%; RT:15.866), n-Hexadecanoic acid (4.74%; RT:36.034), 9,12-Octadecadienoic acid (Z,Z)- (11.88%; RT:39.429), 9,17-Octadecadienal,(Z)- (5.01%; RT:39.500), ethyl oleate (5.27%; RT:39.898), 3a,6-Methano-3aH-indene,2,3,6,7 tetrahydro (4.04%; RT:48.379), and 9,12-Octadecadienoic acid (Z,Z)-,2 hydroxy-1-(hydroxymethyl) ethyl ester (12.68%; RT:48.682). Some of these compounds have antimicrobial, antioxidant, hepatoprotective, hypocholesterolemic as well as cancer preventive activities amongst others. Conclusion: This study showed the bioactive components of therapeutic potentials in L. squarrosulus while creating a platform for screening, isolating and identifying many bioactive components which may be useful in the treatment of the various ailments, disorders and diseases in the nearest future

Antimicrobial activity, phenolic content, and cytotoxicity of medicinal plant extracts used for treating dermatological diseases and wound healing in KwaZulu-Natal, South Africa

Medicinal plants used for wound healing and skin diseases are the key to unlocking the doors to combating problematic skin diseases as resistance of pathogens to pharmaceuticals and allopathic management continues to increase. The study aimed at investigating the antimicrobial efficacies, phenolic content, and cytotoxicity effects of 11 medicinal plant extracts commonly used for treating skin conditions and wound healing in traditional medicine within KwaZulu-Natal. Eleven plant species were separated into different plant parts (bulbs, roots, leaves) and extracted with different solvents. The extracts were assessed for antimicrobial activity against six Gram-positive and seven Gram-negative bacterial strains and four fungi commonly associated with skin conditions using disc diffusion and microdilution techniques. The aqueous methanolic extracts were screened for phenolic content while cytotoxicity tests were performed on all extracts using the brine shrimp lethality and tetrazolium-based colorimetric (MTT) assays. Extracts from Aloe ferox, A. arborescens, and Hypericum aethiopicum were the most active against almost all of the tested bacterial and fungal strains. All plant species exhibited some degree of antimicrobial activity. Total phenolic levels, flavonoids and tannins were also higher for A. ferox, followed by A. arborescens and H. aethiopicum, respectively. The cytotoxicity results of all plant extracts were in the range of 90-100% survival after 24 h in the brine shrimp assay. Extracts considered lethal would demonstrate >50% shrimp death. The MTT cytotoxicity test yielded LC50 values of >1 mg/mL on all extracts indicating that they are not cytotoxic. The observed antimicrobial efficacy demonstrated by some plant species and the general lack of cytotoxic effects on all the tested extracts presents some promising and beneficial aspects of these medicinal plant extracts in the treatment of skin diseases and wound healing. The two Aloe species and H. aethiopicum were among the best extracts that exhibited consistently good antimicrobial activity and warrants further investigations and possible isolation of bioactive principles.The University of KwaZulu-Natal and the National Research Foundation (NRF) of South Africa.http://www.frontiersin.orgam2016Paraclinical Science

Effects and time-kill assessment of amoxicillin used in combination with chloramphenicol against bacteria of clinical importance

With the emergence of multidrug-resistant organisms in an era when drug development faces challenges causing pharmaceutical companies to curtail or abandon research on anti-infective agents, the use of combined existing antimicrobial agents may be an alternative. This study evaluated the effects of combining amoxicillin and chloramphenicol, to which many bacteria have become resistant, in vitro against Gram positive and Gram negative bacteria by agar diffusion, checkerboard and time-kill assays. The test isolates were susceptible to amoxicillin with minimum inhibitory concentrations (MICs) ranging between 0.448 and 500 µg/ml and between 1.953 and 31.25 µg/ml for chloramphenicol. Upon combining these agents, there was a drastic reduction in their MICs indicating an increased antibacterial activity that showed synergistic interaction against all the bacteria. At the highest concentrations, the inhibition zones ranges were 20.33-38.33±0.58 µg/ml for amoxicillin, 27.67-37.67±0.58 µg/ml for chloramphenicol and 31.67-39.33±0.58 µg/ml for the combined agents. The fractional inhibitory concentration indices (FICIs) showed synergy ranging from 0.129 to 0.312 while FICIs for additive interaction were between 0.688 and 1.0. There was no antagonistic interaction. At the 1/2MICs of the combined antibiotics, all the tested bacteria, except for Klebsiella pneumoniae ATCC 4352, Proteus vulgaris CSIR 0030 and Enterococcus cloacae ATCC 13047 were eliminated before 24 h. At the MICs, all the tested bacteria were eliminated except Enterococcus cloacae ATCC 13047 which was almost totally eliminated. Post-antibiotic assessment after 48 h showed that all the cultures were sterile except for that of Enterococcus cloacae ATCC 13047. The lack of antagonism between these antibacterial agents in checkerboard and time-kill assays suggested that combining amoxicillin with chloramphenicol can provide an improved therapy in comparison to the use of each antibiotic individually. The study indicates the potential beneficial value of combining amoxicillin and chloramphenicol in the treatment of microbial infections in clinical settings