This study was conducted to determine the antibiotic resistance
profile of Escherichia coli isolate from apparently healthy domestic
livestock viz: cow, goats and chicken from Oyo State Nigeria. E. coli
was isolated using Eosin Methylene Blue Agar (EMB) and identified by
conventional microbiological technique. The isolate were tested against
14 antibiotics using the disc diffusion method. A total of 42 different
antibiotics resistance profile were observed with each isolate showing
resistance to at least four or more drugs tested. Generally, the E. coli
isolates showed resistance rates of 93.8% to Ampicilin; 15.3% to
Chloramphenicol, 52.7% to cloxacillin, 74.3% Erythromycin, 20.9% to
Gentamicin, 53.8% to Penicillin, 17.7% to Streptomycin, 67.3% to
Tetracyclin, 21.1% to Ceftazidine 70.7% to Cefuroxine, 20.5% to
Cefixine, 28.8% to Ofloxacine, 58.6% to Augmentin, 27.2% to
Nitorfurantion 27.3% to Ciprofloxacin. Statistical analysis showed that
average number of resistance phenotypes per isolate was significantly
higher for cow compared with poultry. A significant public health
concern observed in this study is that multi drug resistant: commensal
E. coli strains may constitute a potential reservoir of resistance genes
that could be transferred to pathogenic bacteria.
The usage of antibiotics is the most essential factors that
promotes the emergence, selction and dissemination of antibiotic-
resistance microorganisms in both veterinary and human medicine
(Daniles et al, 2009). This acquired resistance not only in pathogenic
bacteria but also in the endogenous flora of exposed individuals
(animals and humans).
Also, intensively reared food animals, antibiotic may be
administered to whole flocks rather than individual animals, and
antimicrobial agent may be continuously fed to food animals. Such as
poultry, goats and cattle as growth promoters.
Furthermore, the antibiotic selection pressure for bacteria drug
resistance in animal is high and invariably their feacal flora contains
a relatively high proportion of resistant bacteria (Whitworth et al,
2008, Literak et al, 2010).
The mechanisms for spreading antibiotic resistance from animal to
human and vice versa remains controversial. Coli from chicken has been
shown in human volunteers and there is historical evidence that animals
are a reservoir for Escherichia coli found in humans (Akwar et al,
Fang et al, 2008 reported that the spread of antibiotic resistance
plasmids in E. coli from chickens to human handles or of antibiotic
microorganisms from animal to humans in various countries has been
Resistance has been found in organisms common to both humans and
animals such as Escherichia coli, Salmonella spp., Campylobacter spp.
and Enterococcs among others (Davis et al, 2009). Due to the intricate
balance of micro flora of different habitats within the ecosystem, the
transfer of the resistance genes among bacteria occupying different
habitats has the potential to occur frequently. (Call et al., 2008)
Escherichia coli is a gram negative, rod shape bacterium that is
commonly found in the lower intestine of poikilothermic (warmblooded)
Most Escherichia coli strains are harmless, but some serotype can
cause serious food poisoning in humans and are occasionally responsible
for product recalls due to food contamination (Migular et al., 2007).
Also the harmless strains are part of the normal floral of the gut
and can benefit their host [by producing vitamin k2 and by preventing
the establishment of the pathogenic bacteria within the intestine
(Michael et al., 2002)
Escherichia coli and related bacteria composed of about 0.1% of
the gut flora and fecal oral transmission is the major route through
which pathogenic strains of the bacterium cause diseases (Okoli et al.,
Cells are able to survive outside the body for a limited amount of
time which makes them ideal indicator organisms to test environmental
sample for fecal contamination.
However, a growing body of research that has examined
environmentally persistence of Escherichia coli which can survive fro
extended period of time outside the host (Lee et al., 1996)
Furthermore, the bacterium can also be grown easily and in
expensively in a laboratory setting and has been inextensively
investigated fro over 60 years. Escherichia coli is the most widely
studied and an important species in the field of biotechnology and
microbiology as well, where it has served as the host organism for the
majority of work with recombinant DNA (Davis et al., 2008).
Conclusively, this was done to ascertain the significant of
antibiotics resistance usage in microorganism and human medicines and
also to know the mechanisms for spreading antibiotic resistance of
Escherichia coli in animals and vice versa which remain controversial.