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Journal of Ecosystem & Ecography | ISSN: 2157-7625 | Volume: 8
June 28-29, 2018 | Alexandria, Egypt
International Pre Conference Workshop on
Microbial Ecology & Eco Systems
Plant disease pathogens may cross the ecological border and cause diseases to humans
Elsayed E Wagih
University of Alexandria, Egypt
P
lants, like animals and humans, are known to suffer from a huge number of diseases caused by various pathogens including,
viroids, virusoids, viruses, mycoplasma and spiroplasma, rickettsia, bacteria, protoctista, fungi and nematodes. Due to biological
differences in the anatomy, histology, cytology, physiology, biochemistry and genetic makeup, usually pathogens of each category of
hosts (plants, animals and humans) are confined to only one type of hosts with many known to infect both animals and humans and
are thus termed zoonosis. Although the general notion that plant pathogens are restricted to plants and cannot infect neither animals
nor humans is commonly adopted, it is shown here not to be true. However, research has shown that patients with their immune
systems being compromised (like those having acquired immunodifficiency syndrome, organ or bone marrow transplantations, AIDS,
hepatitis B, steroid treatment, uncontrolled diabetes, cancer or undergoing chemotherapy etc.), many plant pathogens, known as
opportunistic organisms, can infect them with sometimes fatal consequences.
Pseudomonasaeruginosa
,thecausalagentofbacterialblightonlettuceisanopportunistic,nosocomialpathogenofimmunocompromised
individuals. It can invade nearly any tissue in the human body, provided they are already weakened. The bacterium typically infects the
airway, urinary tract, burns, and wounds, and also causes other blood infections. Symptoms vary widely from dermatitis, urinary tract
infections to gastrointestinal infections, endocarditis and even systemic illness (Todar, 2006). To make matters worse, this bacterium is
becoming increasingly antibiotic resistant in institutional settings.
Human health can also be affected by bacterial species used as biocontrol agents for plant diseases.
Pantoea agglomerans
(formerly called
Erwinia herbicola or Enterobacter agglomerans)
, which is known as a plant pathogen and some strains are used for biological control
of fire blight disease of pear and apple has been recognised as an opportunistic organism in immunocompromised patients causing
serious medical conditions in man including septicaemia, septic arthritis, endophthalmitis, periostitis, endocarditis, osteomyelitis and
urinary-tract infections. (Paula
et al.,
2006; Dutkiewicz, 2016). The bacterium may enter human bodies through accidental punctures
by contaminated plant thorns or with contaminated intravenously-administered solutions (Dennis
et al.,
1973).
Similarly, Mucor is a common indoor mold that is implicated in many crop storage diseases of which Mucor rot in apple is merely an
example. Mucor is among the fungi that cause the group of infections in man known as zygomycosis or more precisely mucormycosis.
This type of infection is caused by a number of fungi belonging to the order Mucorales (Hibbett
et al.,
2007) with
Rhizopus oryzae
being
the most common organism isolated from patients with mucormycosis and is responsible for about 70% of all cases of mucormycosis
(Ribes
et al.,
2000, Roden
et al.,
2005).
Rhizopus oryzae
is a fungus that lives worldwide on dead organic matter. It also infects carrots,
pineapples and mangoes.The fungus is an opportunistic human pathogen causaing zygomycosis (or more properly mucormycosis) to
human.The infection typically involves the rhino-facial-cranial area, lungs, gastrointestinal (GI) tract, skin, or less commonly other
organ systems. Black nasal ulceration and periorbital fungal infection known as Mucormycosis, or Phycomycosis is a dangerous
fungal infection usually occurring in the immunocompromised patient, affecting the skin (Cutaneous Zygomycosis), mouth cavity
(Mucormycosis palate) and the regions of the eye, nose, and through its growth and destruction of the periorbital tissues, it will
eventually invade the brain cavity resulting in a rhinocerebral abscess. External symptoms involve necrotic lesions and presence of
cotton-like growth on its surface (James
et al.,
2016).
Aspergillus niger
the causal agent of black mold disease in onion and several other crops, its spores if inhaled can infect the respiratory
system causing a disease called allergic bronchopulmonary aspergillosis or pseudotuberculosis (Vlahakis and Aksamit, 2001;
Greenberger, 2002; Moss, 2002) which involves breathing problems in both immuno-compromised and healthy people. In immuno-
compromised patients, infection with
A. niger
or the common relative,
A. fumigatus
or
A. flavus
can be a life-threatening one. Although
A. flavus
is a rare species, it can similarly cause nasal and sinus infections in such patients
A. niger
was also found to cause fungal
endophthalmitis with its two types, namely endogenous endophthalmitis, which arises from haematogenous spread from a focus
of infection elsewhere in the body and exogenous endophthalmitis, resulting from primary inoculation of the eye following surgery
or penetrating trauma (Kermani and Aggarwal, 2000; Machado Od Ode
et al.,
2003; Hashemi
et al.,
2009; Hosseini
et al.,
2009).
Aspergillus infection can
cause general ill-health and bleeding in the lung and can worsen asthma and cause allergic sinusitis in patients
Elsayed E Wagih, J Ecosys Ecograph 2018, Volume: 8
DOI: 10.4172/2157-7625-C2-035