The challenges of overcoming antibiotic resistance: Plant extracts as potential sources of antimicrobial and resistance modifying agents

The problem of antibiotic resistance, which has limited the use of cheap and old antibiotics, has necessitated the need for a continued search for new antimicrobial compounds. Understanding the mechanisms of resistance is important in the development of strategies to solving the problem. Active efflux of drugs, alteration of target sites and enzymatic degradations are the strategies by which pathogenic bacteria acquire or develop intrinsic resistance to antibiotics. Multi-drug resistance (MDR)pumps, capable of recognizing and expelling a variety of structurally unrelated compounds from the bacterial cell and conferring resistance to a wide range of antibiotics have since been characterized inmany gram positive and gram negative pathogens like Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and, more recently, in mycobacteria. The ability of some chemical compounds (called MDR inhibitors or resistance modifying agents) to modify the resistance phenotype in bacteria by working synergistically with antibiotics in vitro has since been observed. The search for such compounds which can be combined with antibiotics in the treatment of drug resistant infectionsmay be an alternative to overcoming the problem of resistance in bacteria. Crude extracts of medicinal plants stand out as veritable sources of potential resistance modifying agents and the Africanbiosphere promises to be a potential source of such compounds owing to its rich plant species diversity

Characteristics of a bioflocculant produced by a consortium of Cobetia and Bacillus species and its application in the treatment of wastewaters

The characteristics of a bioflocculant produced by a consortium of 2 bacteria belonging to the genera Cobetia and Bacillus was investigated. The extracellular bioflocculant was composed of 66% uronic acid and 31% protein and showed an optimum flocculation (90% flocculating activity) of kaolin suspension at a dosage of 0.8 mg/m., pH of 8, and with Ca2+ as a coagulant aid. The bioflocculant is thermally stable, with a high residual flocculating activity of 86.7%, 89.3% and 87% after heating at 50oC, 80oCKeywords: Extracellular, bioflocculant, consortium, characteristic, Cobetia sp., Bacillus sp

Real-time PCR quantitative assessment of hepatitis A virus, rotaviruses and enteroviruses in the Tyume River located in the Eastern Cape Province, South Africa

We applied real-time RT-PCR (reverse transcription-polymerase chain reaction) to assess the incidence of hepatitis A virus, rotaviruses and enteroviruses in the Tyume River, an important water resource in the impoverished Eastern Cape Province of South Africa. Detection of noroviruses was done using conventional semi-nested RT-PCR. Water samples were collected once monthly from 6 sampling sites over a 12-month period starting in August 2010 and ending in July 2011. Hepatitis A virus was detected in 13% of the samples in concentrations ranging between 1.67×103 genome copies/ℓ and 1.64×104 genome copies/ℓ while rotaviruses were detected in 4% of the samples with concentrations ranging from 9×101 genome copies/ℓ to 5.64×103 genome copies/ℓ. Enteroviruses were not detected in any of the samples, while noroviruses were detected in 4% of the samples. All hepatitis A and rotaviruses positive samples were from the upstream sections of Tyume River while noroviruses were detected in samples from downstream sections only. Statistical analysis showed that occurrence of the viruses in Tyume River was sporadic. Risk analysis showed that hepatitis A virus posed greater risk than rotaviruses for both recreational and domestic water uses. Because of the low infectious dose of enteric viruses, the detection of even low concentrations of hepatitis A virus, rotaviruses and noroviruses in surface water poses a significant risk to public health.Keywords: Hepatitis A virus, rotaviruses, noroviruses, TaqMan real-time PCR, reverse transcription, Tyume River, public healt

In vitro evaluation of the interactions between acetone extracts of Garcinia kola seeds and some antibiotics

The effect of combinations of the acetone extract of Garcinia kola seeds and six first-line antibiotics was investigated by means of fractional inhibitory concentration (FIC) indices as well as by the use oftime kill assays. Using the FIC indices, synergistic interactions were observed largely against gram positive organisms (FIC indices of 0.52 - 0.875) with combinations against gram negatives yieldinglargely antagonistic interactions (FIC indices of 2.0 to 5.0). The time kill assay detected synergy against both gram negative and gram positive organisms with a ≥ 1000 times (≥ 3Log10) potentiation of thebactericidal activity of tetracycline and chloramphenicol (against E. coli ATCC8739 and K. pneumoniae ATCC10031) as well as amoxycillin and penicillin G against Staphylococcus aureus ATCC 6538.Combinations involving erythromycin and ciprofloxacin consistently gave antagonistic or indifferent interactions. We conclude that the acetone extract of G. kola can be a potential source of broad spectrum antibiotics resistance modifying compounds

Remediation of petroleum hydrocarbon polluted systems: Exploiting the bioremediation strategies

The irrepressible quest for a cheap source of energy to meet the extensive global industrialization demand has expanded the frontiers of petroleum hydrocarbon exploration. These exploration activities amongst others often result in pollution of the environment, thus creating serious imbalance in the biotic and abiotic regimes of the ecosystem. Several remediation alternatives have been in use for the restoration of petroleum hydrocarbon polluted systems. In this paper, we present an overview of bioremediation alternative vis-à-vis other cleanup methods and its adaptations in various polluted systems

In vitro time kill assessment of crude methanol extract of Helichrysum pedunculatum leaves

The in vitro antibacterial activities and time kill regimes of crude methanol extract of Helichrysum pedunculatum was assessed using standard microbiological procedures. The experiment wasconducted against a panel of bacterial species made up of clinical, environmental and reference strains. The extract was active against eleven of the twenty-one bacteria tested at a concentration of 10 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.1 – 5.0mg/ml. The average log reduction in viable cell count in time kill assay ranged between 0.17 Log10 to 6.37 Log10 cfu/ml after 6 h of interaction, and between 0.14 Log10 and 6.99 Log10 cfu/ml after 12 h interaction in 1×MIC and 2×MIC of the extract. The extract was bactericidal against 8 of the test bacteria at 1×MIC and against 9 of the test bacteria at 2×MIC from 12 h interaction period. At both MIC levels, the extract was bactericidal to all the reference strains and four of the six environmental strains at both MIC levels after 12 h of interaction. Also the extract was bactericidal to four of the six environmental strains at both MIC levels after 12 h of interaction and bacteriostatic during the first 6 h of interaction. Inhibitory levels of crude methanol extract of H. pedunculatum could be bacteriostatic or bactericidal independentof Gram’s characteristic

Dechlorination of 1,2– dichloroethane by Pseudomonas aeruginosa OK1 isolated from a waste dumpsite in Nigeria

As part of our attempt at isolating and stocking some indigenous microbial species, we isolated a bacterium from a waste dumpsite with appreciable dechlorination activity. 16S rDNA profiling revealed the isolate to be a strain of Pseudomonas aeruginosa and the sequence has been deposited in the NCBI nucleotide sequence database (accession number AJ550306). The bacterium utilized 0.1% (v/v) 1, 2 – dichloroethane (1, 2 – DCE) as sole source of carbon and attained peak cell density of 6.0 × 107 cfu/ml in 48 h. It also has a proportionate increase in chloride release during this period resulting in the release of 80% free Cl-. The bacterium also had dehalogenase activities against other chlorinated organics such as monochloroacetic acid, trichloroacetic acid, dichloromethane, trichloromethane and tetrachloromethane at pH 7.5 and 9.0. Optimum temperature for dehalogenase activity against 1, 2 – DCE was 35oC. Key Words: Dechlorination, 16S rDNA, bioremediation, Pseudomonas aeruginosa OK1. African Journal of Biotechnology Vol.3(10) 2004: 508-51

Wastewater treatment plants as a source of microbial pathogens in receiving watersheds

Wastewater treatment facilities have become sin quo non in ensuring the discharges of high quality wastewater effluents into receiving water bodies and consequence, a healthier environment. Due to massive worldwide increases in human population, water has been predicted to become one of the scarcest resources in the 21st century, and despite large advances in water and wastewater treatments, waterborne diseases still pose a major threat to public health worldwide. Several questions have been raised on the capacity of current wastewater treatment regimes to remove pathogens from wastewaterwith many waterborne diseases linked to supposedly treated water supplies. One of the major gaps in the knowledge of pathogenic microorganisms in wastewater is the lack of a thorough understanding ofthe survival and persistence of the different microbial types in different conditions and environments. This therefore brings to the fore the need for a thorough research into the movement and behavior of these microorganisms in wastewaters. In this review paper we give an overview of wastewater treatment practices with particular emphasis on the removal of microbial pathogens

The proposed mechanism of bactericidal action of eugenol, &#8733-terpineol and g-terpinene against Listeria monocytogenes, Streptococcus pyogenes, Proteus vulgaris and Escherichia coli

The mechanism of antimicrobial activity of essential oils components; - terpineol, g-terpinene and eugenol was studied to evaluate their effect on the bacterial membrane against four strains of bacteria:Listeria monocytogenes, Streptococcus pyogenes, Proteus vulgaris and Escherichia coli. The study was done to observe changes in membrane composition by assaying for the leakage of protein and lipid using Bradford and van Handel’s method respectively. The oils components were capable of inducing cell lysis by the leakage of protein and lipid contents. Eugenol at 2 × MIC was highly effective toward protein content leakage after 120 min of exposure. Alpha terpineol and g-terpinene showed similar effect at 2 × MIC under the same condition. Gamma terpinene displayed the highest activity toward lipid content leakage at 2 x MIC while -terpineol and eugenol showed similar effect after 120 min of exposure. The result revealed that both cell wall and membrane of the treated gram negative and gram positive bacteria were significantly damaged

Determinants and effect of girl child marriage: a cross sectional study of school girls in Plateau State, Nigeria

Background: Child marriage is a major problem contributing to maternal morbidity and mortality in Nigeria. It has effect on both social and health of not only the girl child but the children born to these young mothers. Aim: This study aimed at assessing the determinants of early marriage among secondary school girls in Plateau State and its effect especially on their health and education. Methods: The study was a cross sectional study of young girls in 21 secondary schools across the three geopolitical zones in Plateau state, selected through a simple random sampling technique after obtaining consent from the JUTH ethical committee and permission from the State ministry of education and the principals of the various schools.Results: The study found that while must marriages among girls are forceful marriages, the factors that influenced early marriage was poor educational level of parents, poverty and place of residence. The girls who married among them reported having had some health challenges and educational backwardness as a result of early marriage. Conclusion: This study found that poverty and poor education are the underlying cause of child marriage and child marriage is usually against the will of the girls who desire to be educated.Key words: Early marriage, maternal and childhood morbidity and mortality, Child Right Act, girl child education, puberty, teenage pregnanc