ANTIMICROBIAL AND PHYTOCHEMICAL PROPERTIES OF YOUNGCOCOS NUCIFERA(COCONUT) WATER AND METHALONIC EXTRACT OF THE YOUNGCOCOS NUCIFERA(COCONUT) HUSK
CHAPTER ONE
1.0 INTRODUCTION AND LITERATURE REVIEW
1.1 INTRODUCTION
Medicinal plants represent a rich source of antimicrobials and many other drugs. The potentialsof
higher plants as source for new drugs is still largely unexplored. Antibiotic resistance has become a
global concern (Westhet al., 2004). The clinical efficacy of many existing antibiotics is being
threatened by the emergence of multidrug-resistant pathogens (Bandow, 2003). Many
infectiousdiseases have been known to be treated with herbal remedies throughout the history of
mankind. Natural products, either as pure compounds or as standardized plant extracts, provide
unlimited opportunities for new drug leads because of the unmatched availability ofchemical diversity.
There is a continuous and urgent need to discover new antimicrobial compounds with diversechemical
structures and novel mechanisms of action for new and re-emerging infectious diseases (Rojas et al.,
1992). Therefore, researchers are increasingly turning their attention tolocal herbs, looking for new
leads todevelop better drugs against microbial infections (Benkeblia, 2004).
The increasingfailure of chemotherapeutics and antibiotic resistanceexhibited by pathogenic microbial
infectious agents has led to the screening of several medicinal plants for their potential antimicrobial
activity (Kapila, 2005 ;Runyoro et al.,2006). The rising prevalence of antibiotics resistant pathogenic
microorganisms raises the demand for finding new alternative antimicrobial agents. The drugs already
in use to treat infectious diseaseare of concern because drug safety remains an enormous global issue.
Most of the synthetic drugscause side effects and also most of the microbesdeveloped resistant against
the synthetic drugs (Chanda and Rakholiya 2011). To alleviate this problem, antimicrobial compounds
frompotential plants should be explored. These drugs fromplants are less toxic; side effects are scanty
and alsocost effective. They are effective in the treatment ofinfectious diseases while
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simultaneouslymitigatingmany of the side effects that are often associated withsynthetic antimicrobials
(Harishchandraet al., 2012).
Published studies in medical journals show that coconut in one form or another may provide a wide
range of health benefits. The coconut plant Cocos nucifera (family Arecaceae) is considered as an
important fruit crop in tropical countries. It is commonly available plant with wide variety of
applications in food, drinks, fibers, building materials and various chemicals finding their way into a
huge range of modern day products. Being highly nutritious coconuts have also been studied for
medicinal qualities.
Modern medical science is now confirming the medicinal qualities of Cocos nucifera which are used
for the treatment wide range of infections. Based on the knowledge of the traditional herbs used for the
treatment for local application, coconut husk can be use as a topical antimicrobial. As preliminary
investigation of the use of coconut husk, the antimicrobial activity can be evaluated.
1.2 AIM AND OBJECTIVES
The specific objectives are to:
(a) Evaluate the phytochemical and antimicrobial activities of Methalonic extract of young Cocos
nucifera husk on selected pathogenic microorganisms.
(b) Evaluate the antimicrobial activities andyoung Cocos nucifera water on selected pathogenic
microorganisms
1.3 JUSTIFICATION OF THE RESEARCH
Cocos nucifera husk and Cocos nucifera water are traditionally used in the treatment of wide variety of
diseases, it has been used from time immemorial for the treatment of carcinogenic infections. This
study scientifically justifies the use of young Coconut husk and young Coconut water in traditional folk
medicine and to compare their antimicrobial potency with the commercial antibiotics.
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1.4LITERATURE REVIEW
1.4.1 MEDICINAL PLANTS AS ANTIMICROBIAL AGENT
Medicinal plants have always been considered as a source for healthy life for people. Therapeutical
properties of medical plants are very useful in healing various diseases and the advantage of these
medicinal plants are natural (Kalemba and Kunicka, 2003). In many parts of the world, medicinal plants
have been used for its antibacterial, antifungal and antiviral activities for hundreds of years (Ali et al.,
1998; Barbour et al., 2004; Yasunakaet al., 2005). Researchers are increasingly turning their attention
to natural products and looking for new leads to develop better drugs against cancer, as well as viral and
microbial infections (Ibrahim, 1997; Towers et al., 2001; Koshy et al., 2009). Several synthetic
antibiotics are employed in the treatment of infections and communicable diseases. The harmful
microorganisms can be controlled with drugs and this has resulted in the emergence of multiple drug
resistant bacteria and it has created alarming clinical situations in the treatment of infections.
In general, bacteria have the genetic ability to transmit and acquire resistance to synthetic drugs which
are utilized as therapeutic agents (Murray, 1992; Madunaguet al., 2001; Koshy et al., 2009;
Senthilkumar and Reetha, 2009) Therefore, actions must be taken to reduce this problem, such as to
minimize the use of antibiotics, develop research of resistance among microorganism and to continue
studies to develop new antibiotic and immune modulating compounds with diverse chemical structures
and novel mechanisms of action, either synthetic or natural to control pathogenic microorganisms
because there has also been an alarming increase in the incidence of new and re-emerging infectious
diseases (Ikenebomeh and Metitiri, 1988; Rojas et al., 2003)
Antimicrobial studies have shown that Gram-negative bacteria show a higher resistance to plant extracts
than Gram-positive bacteria. This may be due to the variation in the cell wall structures of Gram-
positive and Gram-negative bacteria. More specifically, Gram-negative bacteria has an outer membrane
that is composed of high density lipopolysaccharides that serves as a barrier to many environmental
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substances including antibiotics (Paz et al., 1995; Vlietincket al., 1995; Kudiet al., 1999; Palombo and
Semple, 2001). Although hundreds of plant species have been tested for antimicrobial properties, the
vast majority of have not been adequately evaluated (Onwuliri and Dawang, 2006; Mahesh and Sathish,
2008).
The coconut (Cocos nucifera L. family Arecaceae) is a well distributed fruit tree all around the world,
providing food, especially in the tropical and subtropical regions and for its many uses it is often called
the “tree of life”. There are 12 different crops of nuts under the name of coconut palm (DebMandal and
Mandal, 2011). Cocos nucifera is widely distributed over the Brazilian northeastern coast, where is
known as “Coco-da-Bahia”. Popular medicinal uses (against arthritis and diarrhea) of coconut husk fiber
have been reported (Rinaldi et al., 2009), but the knowledge of its potential benefit or adverse effects in
human beings is still very preliminary.
Coconut, Cocos nucifera, is a tree that is cultivated for its multiple utilities, mainly for its nutritional
and medicinal values. The various products of coconut include tender coconut water,copra, coconut
oil, raw kernel, coconut cake, coconut toddy, coconut shell and wood based products, coconut leaves,
coir pith etc. It’s all parts are used in some way or another in the daily life of the people in the
traditional coconut growing areas. It is the unique source of various natural products for the
development of medicines against various diseases and also for the development of industrial products.
The parts of its fruit like coconut husk and tender coconut water have numerous medicinal properties
such as antibacterial, antifungal, antiviral, antiparasitic, antidermatophytic, antioxidant, hypoglycemic,
hepatoprotective, immunostimulant. Coconut water and coconut kernel contain micro minerals and
nutrients, which are essential to human health, and hence coconut is used as food by the peoples in the
globe, mainly in the tropical countries. The coconut palm is, therefore, eulogizedas ‘Kalpavriksha’ (the
all giving tree) in Indian classics. India is the third largest coconut producing country, after Indonesia
and the Philippines, having an area of about 1.78 million hectares under the crop. Annual production is
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about 7,562 million nuts with an average of 5 295 nuts/hectare (Rinaldi et al., 2009). In India, the four
south Indian states namely Kerala, Tamil Nadu, Karnataka and Andhra Pradesh account for around
90% of the coconut production in the country (Rinaldi et al., 2009). For thousands of years,
coconutproducts have held a respected and valuable placein Indianfolk medicine. It is believed to be
antiblenorrhagic, antibronchitis, febrifugal, and antigingivitic. In Ayurvedic medicine, the oil, milk,
cream and water of the coconut are all used to treat hair loss, burns and heart problems. In India, the
use of coconut for food, and its applications in the Ayurvedic medicine were documented in Sanskrit 4
000 years ago. Records show that in the United States, coconut oil was one of the major sources of
dietary fats, aside from dairy and animal fats, prior to the advent of the American edible oil
(soybean and corn) industry in the mid-1940s(Dayrit,2005). Virgin coconut oil (VCO) is completely
non-toxic to humans, and is referred to as the “drugstore in a bottle”. In India, the coconut has religious
connotations; it is described as “The fruit of aspiration” and a coconut is offered to the gods and cut at
the start of many new projects. Coconut water is produced by a 5 month old nut that during World War
II, was used in emergencies, and put directly into a patient’s veins. From ancient times the coconut is
used as a very effective remedy for intestinal worms of all kinds. Boiled toddy, known as jaggery, with
lime makes a good cement. Nutmeat of immature coconuts is eaten or extracted cream is used on
various foods.
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1.4.2COCONUT WATER AS POTENTIAL ANTIMICROBIAL AGENTS
Coconut water (coconut liquid endosperm), with its many applications, is one of the world’s most
versatile natural product. This refreshing beverage is consumed worldwide as it is nutritious and
beneficial for health. There is increasing scientific evidence that supports the role of coconut water in
health and medicinal applications. Coconut water is traditionally used as a growth supplement in plant
tissue culture/micro propagation. The wide applications of coconut water can be justified by its unique
chemical composition of sugars, vitamins, minerals, amino acids and phytohormones.
Coconut water is a natural liquid that contains many biologically active compounds. These include
numerous antioxidant compounds that have the ability to scavenge free radicals in the body. It also
contains cytokins, a plant chemical which has shown anti-aging and anti-carcinogenic effects. Coconut
water also contains B vitamins, which are water soluble and are required for cellular functions (Jannick
and Paull, 2008). Coconut water contains a variety of inorganic ions such as calcium, magnesium,
phosphorus, sodium, potassium and selenium (Patrick and Offler, 2001). Further, other components
found in coconut water include sugars, sugar alcohols, lipids, amino acids, nitrogenous compounds,
organic acids and some enzymes.
They play different functional roles in plant and human systems due their distinct chemical properties
(Pummer et al, 2001). Many studies have shown that the antiviral, antibacterial, anti-inflammatory and
antioxidant activities of coconut water may help ease a number of minor to severe health conditions.
This nutrient rich drink has been used to regulate blood pressure, blood sugar, and cholesterol levels,
and it has been found to boost energy levels and increase metabolism in human body. Other conditions
that it has been found to be effective in treating include stomach flu, dysentery, indigestion,
constipation, intestinal worms, urethra stones, malfunctioning kidneys, dry and itchy skins, age spot and
wrinkles (Campbell-Falck, 2000). Similarly, some recent studies have found thatcoconut water can help
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increase high density lipoprotein (good) cholesterol, which makes it a wonderful natural treatment for
maintaining good cardiovascular health. Young coconut water has estrogens-like characteristics. It
mixes easily with blood, and was used during World War II in emergency transfusions (Pummer et al,
2001). Coconut water can also serve as emergency short-term intravenous hydration fluid. This is
possible because it contains a high level of sugar and other salts that make it possible to be used in the
bloodstream, much like the modern lactate Ringer Solution or a dextrose/water solution as an
intravenous solution (Anurag and Rajamohan, 2003). In Eastern Nigeria, coconut water is used for
several medicinal purposes which include management and treatment of various disorders such as
gastrointestinal disorders, high blood pressure, dehydration, kidney malfunction, anxiety, etc.
Glutathione peroxidase (GPX) is an enzyme which acts on lipid hydroperoxide (LHP) substrates that are
released from membrane phospholipids by phospholipaseA2. It can utilize cholesterol hydroperoxide
and hydrolyzes hydrogen peroxide (H
O) at low concentration (van Overbeek, 2007). The antioxidant
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enzyme, GPX, catalyze the reaction of HO and hydroperoxides formed from fatty acid, thereby
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effectively removing toxic peroxides from living cells. It plays the important role of protecting cells
from potential damage by free radicals, formed by peroxide decomposition (Van Overbeek et al.,
2007).Lipid peroxidation is an established mechanism of cellular injury, and is used as an indicator of
oxidative stress. Polyunsaturated fatty acids peroxides generate malondialdehyde (MDA) and 4-
hydroxyalkanals upon decomposition (Alleyne et al., 2005).
Superoxide dismutase (SOD) decomposes superoxide anion into hydrogen peroxide and oxygen at very
high rates. Superoxide radical is involved in diverse physiological and pathophysiological processes
(Alleyne et al., 2005). Lipid profile is a general term that is given to tests for high density lipoprotein,
low density lipoprotein, total cholesterol and triglycerides. A shift in the normal level of any of these
components of lipid profile is of interest to cases of cardiovascular disorders (Mauney et al., 2006).
Documented scientific evidence on the various medicinal applications of coconut water has been scarce
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in this part of the world. Hence, the present study investigated the antimicrobial property of young
coconut water on pathogenic microorganisms. Coconut water has been extensively studied since its
introduction to the scientific community in the 1940s. In its natural form, it is a refreshing and nutritious
beverage which is widely consumed due to its beneficial properties to health, some of which are based
on cultural/traditional beliefs. It is also believed that coconut water could be used as an important
alternative for oral rehydration and even so for intravenous hydration of patients in remote regions
(Mauney et al., 2006). Coconut water may also offer protection against myocardial infarction (Mauney
et al., 2006).
Interestingly, a study has shown that regular consumption of either coconut water or mauby (a liquid
extracted from the bark of the mauby tree, Colubrinaarborescens), or particularly, a mixture of them, is
effective in bringing about the control of hypertension (Shaw and Srivastava,2004). Apart from that,
coconut water is widely used in the plant tissue culture industry. The extensive use of coconut water as a
growth-promoting component in tissue culture medium formulation can be traced back to more than half
a century ago, when Wayneet al. first introduced coconut water as a new component of the nutrient
medium for callus cultures in 1941 (Shaw and Srivastava,2004).
From a scientific viewpoint, the addition of coconut water to the medium is rather unsatisfactory, as it
precludes the possibility for investigating the effects of individual components of the medium with any
degree of accuracy. The question of which components cause the growth stimulation arose immediately.
Besides its nutritional role, coconut water also appears to have growth regulatory properties, e.g.,
cytokinin-type activity (Van Overbeek, 2007).Some of the most significant and useful components in
coconut water are cytokinins, which are a class of phytohormones (Shaw and Srivastava, 2004). The
first cytokinin, N6-furfuryladenine (kinetin) was isolated from an autoclaved sample of herring sperm
DNA in 1955. In 1963, Letham isolated trans-zeatin, the first naturally-occurring cytokinin, from a plant
source (unripe corn seeds) (Shaw and Srivastava, 2004). In addition to various plant-related functions, it
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was also found that some cytokinins (e.g., kinetin and trans-zeatin) showed significant anti-ageing, anti-
carcinogenic, and anti-thrombotic effects. Furthermore, micronutrients (nutrients needed in small
quantities) such as inorganic ions and vitamins in coconut water play a vital role in aiding the human
body antioxidant system. Hyper metabolism gives rise to an increased production of reactive oxygen
species (or free radicals), as a result of increased oxidative metabolism. Such increase in free radicals
will cause oxidative damage to the various components of the human cell, especially the polyunsaturated
fatty acids in the cell membrane, or to the nucleic acids in the nucleus. Fortunately, living organisms
have well developed antioxidant systems to neutralize the most detrimental effects of these oxidizing
species. Micronutrients have important functions in this aspect. For example, they act directly to quench
free radicals by donating electrons, or indirectly as a part of metallo enzymes (a diverse class of
enzymes that require a catalytic metal ion for their biological activity) such as glutathione peroxidase
(selenium) or superoxide dismutase (zinc, copper) to catalyse the removal of oxidizing species.
1.4.3COCONUT HUSKAS POTENTIAL ANTIMICROBIAL AGENTS
The husk fibers of coconut (Cocos nucifera) are reported to be used by people of rural areas of South
India for daily cleaning their teeth. A thorough review of literature has revealed few studies on
beneficial effects of husk of C. nucifera namely, antibacterial activity against Vibrio species [4] and
Staphylococcus aureus,(Campbell-Falck,2000)antileishmanial(Pummer et al ,2001) and
antitumoral(Anurag and Rajamohan,2003) properties. Studies conducted by Alvianoet al have also
suggested in vivo and in vitro analgesic and free radical scavenging properties of this plant material.
(Van Overbeek,2007) It is reported that certain plants like C. nucifera were used as teeth blackening
agents by tribal population of Asia and suggested that this form of bodily inscription made a positive
contribution to health status in these population due to the antimicrobial properties of this plant.
(VanOverbeek et al., 2007)Although coconut husks have been used for maintaining oral hygiene for
many years, there is no scientific evidence for the beneficial effects of this plant material, with respect to
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antimicrobial properties against common cariogenic bacteria. Therefore, the present study was designed
to find scientific evidence on valuable effects of this traditional practice. Previous studies showed that
aqueous C. nucifera husk fiber extracts present important biological activities such as antimicrobial,
antiviral, antinociceptive, anti-inflammatory, antioxidant and antineoplasic properties (Esquenazi et al.,
2002; Alviano et al., 2004; Rinaldi et al., 2009). Coconut husk fiber is rich in polyphenolic compounds.
The C. nucifera husk fiber aqueous extracts are mainly composed by catechin, epicatechin and
condensed tannins (B-type procyanidins) (Esquenazi et al., 2002). Plant phenols represent an important
group of natural antioxidants and some of them are potent antimicrobial compounds (Chakraborty and
Mitra, 2008). In general, polyphenols can prevent chronic diseases by their antioxidant, free radical
scavenger and metal chelator properties (Daglia, 2012).
The industrial use of this plant generates large amounts of husk fiber as industrial reject, featuring an
environmental problem. continuous interest in searching for medicinal plants with antimicrobial activity
and in expanding the knowledge about the phytochemical profile of C. nucifera, the purpose of this
study was to investigate the antimicrobial activity of methalonic extract of the husk fiber of the C.
nuciferaand C. nucifera wateragainst bacteria (Staphylococcus aureus, Salmonella typhii,Escherichia
coli,Proteus mirabilis ,Steptococcushaemolyticus,Streptococcus faecalis, Pseudomonas aerugenosa,
Pseudomonas aerugenosa(ATCC 29853), Staphylococcus aureus(NCIB 950), Escherichia coli(ATCC
35218) and fungi (Candida albican, Aspergillus flavus and Aspergillus niger).
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1.4.4 PHYTOCHEMICAL PROPERTIES OF MEDICINAL PLANTS
1.4.4.1 SAPONINS
Saponins are steroids and triterpene glycosides. They are called as saponins due to their soaplike
properties. Saponins possess anti-ulcer, anti-tumor and anti-diabetic properties. Four saponins,
bugbanosides have been isolated from Cimifuga simplex.Solanine is an example of saponins found in
family Solanaceae, such as thepotato(Solanumtuberosum) and has fungicidaland pesticidalproperties and
was firstisolated in 1820.A number of studieshave shown saponins to have inhibitory effects onprotozoa.
Saponins from Quillajasaponariaand Acaciaauriculoformiswere found to be antiprotozoal in-vitro
withbutanol as the main active component (Wallace, 2004).
ImageFigure 1: Chemical structure of Saponin
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1.4.4.2 TANNINS
Tannins are biologically active compounds having diverse antimicrobial actions. Tannins have wide
applications in food, pharmaceutical and leather industries. Tannic acid is the example of gallotannins
that is hydrolysable. It is extracted fromthe roots and fruits of Rhustrilobata. Tannic acid has
antibacterial,antidermatotic, antihemorrhoidal, antiseptic, astringent, antiulcer and antiviral properties. It
also has well-described antimutagenic and antioxidantactivities (Wallace, 2004). The mechanism of
action of tannin includes: Protein binding, adhesin binding, enzyme inhibition, ssubstrate deprivation,
ccomplex with cell wall, mmembrane disruption, metal-ion complexation. (Cowan, 1999)
ImageImageImage
ImageFigure 2: Chemical structure of Tannin
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1.4.4.3 QUINONES
Aromatic rings that have two ketone groups are known as Quinones. An anthraquinone wasisolated from
Cassia italica, which inhibited the growth of Bacillusanthracis, Cynebactericimpseudodiphthericumand
Pseudomonas aerugenosa. Anantifungal naphtaquinone has been isolated from the
Swertiacalycina.Hypericinis an anthraquinone that was extracted from Hypericumperforatum. Itgained
popularity as an anti-depressant and it had general antimicrobial properties(Wallace, 2004).The
mechanism of action includes: Adhesin binding, complex with cell wall,enzyme inactivation. (Cowan,
1999).
ImageImageImage
ImageFigure 3: Chemical structure of Quinones
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1.4.4.4 FLAVONOIDS
Flavonoids are the largest group of polyphenolic compounds. They are widely distributedthroughout the
plant kingdom. There are four major groups of flavonoids, anthocyaninsflavones, flavonols and
isoflavones.Genistein is one of several known isoflavones. It is found in a number of plantsincluding
lupin, fava beansand Flemingiavestita. Various studiesdemonstrated that moderate doses of genistein
has inhibitory effects on cancers of the prostate, cervical, brain and breast(Wallace, 2004). The
mechanism of action is adhesin binding (Cowan, 1999)
ImageImage
ImageFigure 4: Chemical structure of Flavonoid
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1.4.4.5 ALKALOIDS
Alkaloids are heterocyclic nitrogenous compounds . The first useful alkaloid frommedicinal point of view
was morphine. It was isolated in 1805 from poppy plant Papaversomnife. Alkaloids have antimicrobial
properties. The tropane alkaloids have been isolated from leaves ofErythroxylum mooni, a medicinal plant
from Sri Lanka, which display broad spectrumantifungal activity(Wallace, 2004). Alkaloid mechanism of
action incude: Intercalation into cell wall and/or DNA. (Cowan, 1999).
Image
ImageFigure 5: Chemical structure of Alkaloid
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1.4.4.6 PHENOLICS AND POLYPHENOLS
Plants are able to make a wide range of aromatic compounds, more common among them arephenols or
their derivatives having oxygen substitution .Vanillic acid has been extracted from the
Aristolochiamollissima. Vanillic acid hasantioxidant properties and hence is useful against cancer.
Caffeic acid ispresent in common herbstarragon and thyme which is effective against all types
ofmicroorganisms. Cinnamicacid obtained from oil of cinnamon, or from balsamsand catechol present in
the juice ofMimosa catechu are also the examples of phenolic compounds derived from plants(Wallace,
2004).
Image
Image
Figure 6: Chemical Structure of Phenolics (Catechol)
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1.4.5 BACTERIA INFECTIONS
1.4.5.1 STAPHYLOCOCCUS AUREUS
Staphylococcus aureus causes boils, styes, pustules, impetigo, infections of wounds (cross infections),
ulcers and burns, osteomyelitis, mastitis, septicaemia, meningitis, pneumonia, and pleular empyema.
Also, included are toxic food-poisoning (rapid onset on fever), toxic shock syndrome and toxic skin
exfoliation (Lowy, 2003). According to Cheesbrough (2000), Staphylococcus aureusis carried in the
nose of 40% or more of healthy people. It is a pathogen of great concern because of its intrinsic
virulence, its ability to cause a diverse array of life-threatening infections, and its capacity to adapt to
different environmental conditions (Lowy, 2003). The mortality of Staphylococcus aureusbacteremia
remains approximately 20–40% despite the availability of effective antimicrobials (Lowy, 2003) and it
is now the leading overall cause of nosocomial infections.
1.4.5.2 PSEUDOMONAS AERUGENOSA
Pseudomonas aerugenosa is an opportunistic human pathogen associated with nosocomial infections of
immunocompromised individuals as a result of burns or other severe trauma, underlying diseases,
including cancer, diabetes and cystic fibrosis (CF), deliberate immunosuppression and major surgery
(Poole, 2001). Pseudomonas aeruginosacauses urinary tract infections, respiratory system infections,
dermatitis, soft tissue infections, bacteremia and a variety of systemic infections. Infections are often
difficult to eradicate due to Pseudomonas aeruginosabeing resistant to many antimicrobials
(Cheesbrough, 2000) and this intrinsic resistance has long been attributed to the outer membrane, a
barrier of limited permeability (Poole, 2001). A study on the resistance of Pseudomonas
aeruginosaisolates from pus samples obtained from wound of patients in Enugu and Abakaliki using the
paper disc diffusion technique showed that, out of fifty pus samples screened, 34(64%) yielded
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Pseudomonas aeruginosa(Amadiet al., 2009). The sensitivity of the Pseudomonas aeruginosawas then
investigated using amoxycillin, co-trimoxazole, streptomycin, gentamicin, chloramphenicol and
ciprofloxacin and the highest resistance obtained was recorded for amoxycillin (88.2%), followed by co-
trimoxazole (76.5%), streptomycin (67.6%), gentamicin (58.8%), chloramphenicol (58.8%) and
ciprofloxacin (23.5%) (Amadiet al., 2009).
1.4.5.3 SALMONELLA TYPHI
Typhoid fever is a life-threatening illness caused by the bacterium Salmonella typhithat lives only in
humans. Typhoid fever remains a serious health threat especially in 19 developing countries where it is
estimated that over 20 million cases occur annually resulting in greater than700,000 deaths globally.
Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. A small number of
persons who recover from typhoid fever remain carriers of the bacteria. In both cases, S. typhiare shed in
the faeces (Cheesbrough, 2000). It has been a major human pathogen for thousands of years, thriving in
conditions of poor sanitation, crowding, and social chaos (Bruschet al., 2010). The antibiotic of choice
for many years was chloramphenicol, but like many pathogens, chloramphenicol-resistant strains have
emerged. In addition, many strains have developed resistance to ampicillin and
trimethoprim/sulfamethoxazole, which are considered appropriate alternatives to chloramphenicol
(Mills-Robertson et al., 2002). In a study by Mills-Robertson et al., (2003), 30 strains of bacteria out of
a total of 58 isolates (52%) exhibited multiple drug resistance (MDR) with 10 strains being resistant to
all three first line antibiotics.
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1.4.5.4 ESCHERICHIA COLI
Escherichia coli is one of the main causes of nosocomial infections in humans (Oloweet al., 2008). It is
naturally found in the intestinal tract, in soil and water. Escherichia colicauses infections of wounds,
peritonitis, sepsis, endotoxin induced shock, diarrhoeal disease, meningitis and bacteraemia in neonates
and it is also the commonest pathogen isolated from patients with cystitis with recurring infections being
common in women (Cheesbrough, 2000). The organism is of clinical importance due to its cosmopolitan
nature and ability to initiate, establish and cause various kinds of infections (Oloweet al., 2003). It is one
of the organisms most 20 frequently isolated from different clinical cases of diarrhoea and others
(Okekeet al., 1999; Oloweet al., 2003). A study by Oloweet al., (2008) demonstrated Escherichia
colimulti-drug resistance in isolates from clinical samples obtained from patients at LadokeAkintola
University Teaching Hospital, Osogbo, Osun State, Nigeria. Seven antimicrobials were used during the
study and the prevalence of strains resistant to antimicrobials were; Tetracycline (91.6%), Ampicillin
(86.7%), Sulphnamide (77.8%) and Gentamicin and Nalidixic acid which were (39.3%) and (4.1%)
respectively. A total of seven antibiotic resistance profiles were obtained with over 64% of the isolates
showing multi-drug resistance. The isolates with high multi-drug resistance profiles were found to
possess multiple plasmids with large sizes in the range less than 6–25 kb. Very large resistance levels
greater than 85% were detected against Tetracycline, Sulphnamide, and Cotrimoxazole while Nalidixic
acid showed least resistance of 4.1% among the isolates (Oloweet al., 2008). Majority of the isolates
were positive for betalactamase production when subjected to starch paper method (Oloweet al., 2008).
.