Serratia is a genus of Gram-negative, rod-shaped bacteria that commonly lives in moist environments and the human digestive, urinary, and respiratory tracts. The most common species, S. marcescens, is an opportunistic pathogen that frequently causes hospital-acquired infections through contact with contaminated surfaces or equipment. While generally considered non-pathogenic, some Serratia species can cause serious infections like meningitis or endocarditis, especially in infants and immunocompromised individuals. Proper cleaning and disinfection of medical equipment is important to prevent transmission between patients.

2. SERRATIA :-D
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gamma Proteobacteria
Order: Enterobacteriales
Family: Enterobacteriaceae
Genus: Serratia

3. Serratia is a genus of Gram-negative,
facultatively anaerobic, rod-shaped bacteria
of the Enterobacteriaceae family.
•This is a Gram negative rod that thrives in
moist environments.
•It frequently contaminates solutions and
hospital equipment and the human
reservoirs are the urinary and respiratory
tracts as well as the gastrointestinal tract of
children.

4. The genus is named after Serafino
Serrati, an Italian physicist.

5. The most common species in the genus,
S. marcescens, is normally the only
pathogen and usually
causes nosocomial infections.
However, rare strains of S. plymuthica,
S. liquefaciens, S. rubidaea, and
S. odoriferae have caused diseases
through infection.

6. * Members of this genus produce characteristic
red pigment, prodigiosin , and can be
distinguished from other members of the family
Enterobacteriaceae by its unique production of
three enzymes: DNase, lipase, and gelatinase.
* In the hospital, Serratia species tend to
colonize the respiratory and urinary tracts, rather
than the gastrointestinal tract, in adults.

7. •Serratia infection is responsible for about 2% of
nosocomial infections of the bloodstream, lower
respiratory tract, urinary tract, surgical wounds,
and skin and soft tissues in adult patients.
•Outbreaks of S. marcescens meningitis, wound
infections, and arthritis have occurred in pediatric
wards.
•Serratia infection has caused endocarditis and
osteomyelitis in people addicted to heroin.
•Cases of Serratia arthritis have been reported in
outpatients receiving intra-articular injections.

8. •S. marcescens was once thought to be a non-pathogenic
bacteria.
•Because of the red pigment it produces, it was widely
used to trace bacterial transmission and to study settling
and drifting of bacteria in air currents.
•In 1950 the US Navy conducted a secret experiment
called “Operation Sea-Spray” to study wind currents that
might carry biological weapons.
•They filled balloons with S. marcescens and burst them
over San Francisco.
•Shortly thereafter, doctors in the area noted a drastic
increase in pneumonia and urinary tract infections.

9. •Some strains of S. marcescens are capable of
producing a pigment called prodigiosin, which
ranges in color from dark red to pale pink, depending
on the age of the colonies.
•S. marcescens has a predilection for growth on
starchy foodstuffs, where the pigmented colonies are
easily mistaken for drops of blood.

10. •In 1819, Bartolomeo Bizio, a pharmacist from
Padua, Italy, discovered and named S.
marcescens when he identified the bacterium as the
cause of a miraculous bloody discoloration in a
cornmeal mush called polenta.
•Bizio named Serratia in honor of an Italian physicist
named Serrati, who invented the steamboat, and
Bizio chose marcescens (from the Latin word for
decaying) because the bloody pigment was found to
deteriorate quickly.

12. •Since 1906, physicians have used
S marcescens as a biological marker for studying
the transmission of microorganisms because, until
the 1950s, this bacterium was generally considered
a harmless saprophyte.
•Only since the 1960s has S marcescens been
recognized as an opportunistic pathogen in
humans.
•Derivatives of prodigiosin have recently been
found to have immunosuppressive properties and
antitumor activity in vivo.

13. International
The yearly incidence of Serratia bacteremia is
1.03 per 100,000 population, with 47% of
episodes having their onset in the community.
The prevalence of Serratia species as a cause of
nosocomial infections is diminishing, but these
bacteria are still able to cause hospital outbreaks,
especially in intensive care units.

14. Significance in endoscopy
If more evidence is required ofthe pivotal role of
adequate mechanical cleaning in endoscope
reprocessing then it is provided by Serratia
marcescens.
Several outbreaks of S. marcescens infection have
been tracked to bronchoscopic transmission. In an
outbreak involving three fatalities, the instrument
had been inadequately cleaned but then subjected
to a full ethylene oxide sterilising process,
underlining the fact that any attempts at sterilisation
or disinfection are likely to be ineffective in the
presence of inadequate cleaning.

15. Mortality/Morbidity
In a population-based study
of Serratia bacteremia, the 7-day and 6-month
mortality rates were 5% and 37%, respectively.
Serratia meningitis and Serratia endocarditis
carry a high mortality rate.
Serratia species cause less than 6% of cases of
hospital-acquired bacterial pneumonia.
S marcescens causes 11% of burn-related
surgical wound infections.

16. Disease
Significant cause of health care associated
pulmonary, urinary, and surgical site infections.
Mode of transmission
The organism is usually transmitted from person
to person via the nahds of HCW's or from
environmental reservoirs to patients.

17. Sex
Most (68%) episodes of Serratia bacteremia
occur in males.
Age
Outbreaks of Serratia infection occur in
neonates and infants. In adults,
mostSerratia infections are isolated, but
occasional nosocomial outbreaks occur.

19. http://emedicine.medscape.com/article/228495-
overview#showall
http://en.wikipedia.org/wiki/Serratia
http://www.health.qld.gov.au/EndoscopeRepro
cessing/module_1/1_3d.asp