Evteeva N. I., Rechkin A.I.
The new places of reservation Enterobacteriaceae
in natural systems
Nowadays, investigators focus attention at enterobacteria because of their biological and ecological
adaptations and their possibility to live for a long time in human and animal
organisms and their wide spreading in environment like many other infections.
Many aspects of investigation of places of reservation and ecology of enterobacteria are not solved, but for last years works
about distribution of these microorganisms on living and unliving
objects have appeared (4). These organisms are also opportunistic pathogens for
humans as well as for animals (2, 5, 6).
Besides, Enterobacteriaceae
were isolated from soil (4, 11), herbaceouse and arboreous plants, seeds and fresh vegetables (9, 10).
All
terrestrial ecosystems consist of aboveground and belowground components
which interact and influence community- and ecosystem-level processes
and properties. These components are closely interlinked at the
community level, reinforced by a greater degree of specificity
between plants and soil organisms. A combined aboveground-belowground approach
to community of microorganisms and ecosystem ecology makes clear our understanding
of the regulation and functional significance of biodiversity of enterobacteria (8).
Thus, during our
investigations the new places of reservation and participants of circulation enterobacteria in natural systems on the chain: soil –
plants – insects were studied.
Material and methods
Objects of
investigation. For searching of enterobacteria we
selected bees (Apis mellifera) –
74 probes, substrates of ant-hills (Formica(s.str.) aquilonia Yarr., Formica(s.str.) pratensis Retz.) – 57 probes, and worms (Lumbricus terrestris L.)
– 105 probes.
Besides, we investigated
some honey-producing plants, typical for our region: Chamaenerium angustifolium (L) Scop.
– 9 probes, Tilia cordata. Mill.
– 50 probes, Trifolium pretense L. – 45 probes, Taraxacum officinale Wigg. – 23 probes, Rubus
idaeus L. -35 probes.
We analyzed surface and
tissue of steel and leaves, the whole microflora of
the flowers for a period when insects visited them.
All
bacteriological procedures were performed according to the standard methods.
Analyses for coliform bacteria were performed by
using m-Endo agar and Ploskireva media.
Enterobacteriaceae were discovered in the almost
analyzed probes in our investigations. Totally 444 probes of natural system
were analyzed. Isolated cultures were identified as Serratia, Hafnia, Klebsiella,
Enterobacter, Citrobacter,
Proteus, Morganella, Providencia,
Escherichia, Erwinia.
Results and discussion.
Klebsiella (37%) and
Citrobacter (40%) were shown to dominate genuses of enterobacteriae in gut
of worms. Besides, we isolated Serratia, Hafnia, Citrobacter, Proteus,
Escherichia, Erwinia during analyzing of worm’s
guts.
Investigation of substrates of
ant-hills showed their contamination by Enterobacter (44%),
which also dominanted in content of surface’s microflora of neighboring plants (67%), these plants often
were infected with plant louse. Klebsiella (18,5%)
is another group of enterobacteriae discovering in
substrates of ant-hills.
Enteroflora of bees is the most diverse and includs 10 genuses of Enterobacteriaceae.
Erwinia (30%) was indicated in the most cases.
The same bacteria dominated in enteroflora of flowers
of horney-producing plants: Tilia cordata. Mill. (42%), Taraxacum officinale Wigg. (78%),
Rubus idaeus L.(57%). Serratia was
discovered on Tilia cordata. Mill.,
Rubus idaeus L., and Proteus, Providencia, Escherichia on Rubus idaeus L..
The
highest degree of isolation and diversity of enterobacteriae
was presented on the flowers of the honey-producing plants in comparing on
vegetative parts.
The isolation of Klebsiella and Citrobacter
in substrates of worm’s guts can be connected with enrichment of soil
components by organic substrate, witch enhance processes of denitriphication
and ammoniphication in soil. Some authors found the
same microorganisms in plant’s rhizosphere in the
zone with higher concentration of organic acids and gumin
substrates (11). Soil and sediment particles are believed to function as microecological niches for surviving and perhaps
replication of bacterial species (3).
It is significant, that enteroflora substrates of ant-hills is the same to the enteroflora of worm’s guts. Serratia, Klebsiella, Enterobacter,
Citrobacter, Providencia,
Escherichia, Erwinia were discovered in the both.
Klebsiella pneumoniae
and Enterobacter cloacae from components of ant-hills
were found naturally according to our point of view. In ant-hills such
important biogeocenotic processes as
nitrogen-fixation takes place and these microorganisms active participate in
it. Duncan and Razzell (7) reported about the
isolation of Klebsiella
and Enterobacter
from tree needles and bark in a forest environment, from within living white
fir trees (1). The structure of ant-hills analyzed
by us involved the same material. We consider the ant-hills as reservoir for persistention Enterobacteriaceae
in nature and it is necessary to investigate them attentively.
The wide diversity
microorganisms of Enterobacteriaceae in microflora
of bees can be explained by their ability during their fly on a large territory
to have a contact with different substrates and honey-producing plants, which
has very polymorphal microflora.
The association of Enterobacteriaceae
with other botanical material has been reported on several occasions.
Thus, during our
investigation worms, substrates of ant-hills, bees and honey-producing plants
was shown can be reservoir of Enterobacteriaceae in
environment and take part in the chain of circulation of them in natural
systems.
Literature cited:
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