Enterococci are normal flora of the intestinal
tract, the oral cavity and the vagina. They are relatively a virulent in
healthy individuals but may act as pathogens in hospitalized patients1,2.
are gram-positive cocci (diplococcic), arrange in pairs
or in short chains. Though, they are commensal of the intestine, some also cause
urinary and other infections3.
species were formerly categorized in the genus streptococcus, e.g. S. fecalis, but DNA-rRNA homology
studies show that they differ from the streptococci4. Nineteen
species are recognized. E. faecalis (80-90%) and E fecalis (5-10%)
showed the most common species that cause of the infection. An increase in isolation rate of Efaecium
& other species from various clinical samples were recently observed6,
For epidemiological investigation of an
outbreak and also for clinical decisions identification of species is very
important, particularly with regard to therapy, since antimicrobial susceptibility
differs by species5.
It is observed that the
second most commonly reported cause of surgical wound infections and also
hospital acquired urinary tract infections is the Enterococcus sp. It is also reported that Enterococcus is the third most common cause of bacteremia8,9.
faecalis infections are mainly due to several factors that
are thought to contribute. In animal models infection, a plasmid-encoded hemolysis,
called the cytolysin, is important for pathogenesis, and the cytolysin in
combination with high-level gentamicin resistance
is associated with a five-fold increase in risk of death in human bacteremia
patients10,11,12 . In
animal models of infection a plasmid-encoded
factor called “aggregation substance” plays an important role for
For almost a century an
important cause of bacterial Endocarditis is Enterococci species. However,
during the past decade, there has been a worldwide trend in increasing
occurrence of enterococci (in the hospitals), a shift in the spectrum of
enterococcal infections, and emergenceof antimicrobial resistance among such
isolates14.In US, the second most common cause of nosocomial
infections were Enterococci15.
generally have been intra – abdominal and intra – pelvic abscesses or
post-surgery wound infections14.Commonly in the GIT, it is found
that enterococci are usually part of a mixed flora. In mixed infections the
exact role of enterococci is somewhat murky16.Blood stream
infections (BSIs) is the third most frequent infection caused by these
organisms15. Central nervous system (CNS) and neonatal infections
are the other infections with lower frequency. Respiratory tract infections,
osteomyelitis, or cellulites are rarely caused by these bacteria17.
When there is an isolation of Enterococci from a rectal swab or faecal specimen
collected from a patient with diarrhoea, this isolation should not be considered
as infection but instead it is a colonisation18.
These days Since Enterococcus
species is emerging as nosocomial pathogens, it is important to know the
changing patterns of the Enterococcus
infections and the antimicrobial susceptibility patterns. In view of
this, the present study will be aimed to isolate Enterococcus species from clinical samples and to determine their
Enterococcus are gram positive cocci typically
arranged in paris and short chains,and is non-motile and non capsulate. The
cocci are facultatively anaerobic and grow optimally at 35oC , although
most isolates can grow in the temperature range 10oc to 45oc.
They grow readily on blood agar media, with large, white colonies appearing
after 24 hours of incoubation: the colonies are typically nonhemolytic but can
be alfa-hemolytic or beta-hemolytic. It grows readily on ordinary nutrient
media and on MacConkey agar, on which it froms small (0.5-1mm), usually
The Enterococci posses
several distinctive features separating them from sterptococci. The