Serratia marcescens is a Gram negative, rod shaped bacterium belonging to the family Enterobacteriaceae. It is known to cause several nosocomial infections, especially, catheter-induced bacteremia, UTI, and wound infections.
Given its omnipresence in the environment, and its partiality towards moist conditions, S. marcescens proliferates in the bathrooms, where it is seen as a pinkish discoloration and oily film proliferating on soap and shampoo residues and phosphorus-containing materials. Once the bacteria have been established, total annihilation is quite tricky, but can be done by applying a bleach based sanitizer. The microbe is also found in the sub-gingival bio-film of the teeth. These microbes also synthesize a reddish-orange pigment called prodigiosin that could result in extrinsic staining of the teeth. It also has a fondness for growth on starchy foods, where the pigmented colonies are mistaken for drops of blood.
Serratia Marcescens SymptomsSepsis or bacteremia is the commonest presenting symptom of S. marcescens; and is seen as fever with chills.
Urinary tract infection is another common manifestation. Clinical features include: frequent urination, burning during urination, blood and blood in the urine and fever.
Respiratory tract infection is demonstrated as fever, cough with expectoration, wheezing and gasping and chest pain.
Meningitis or cerebral abscesses due to the microbe develop in children; and becomes apparent as: fever, vomiting, seizures, and coma.
Intra-abdominal infections cause liver, gall bladder and pancreatic abscesses and peritoneal exudates.
Osteomyelitis and arthritis are relatively common too; and are seen as swollen joints, redness and pain in the affected joints, stiffness and difficulty in movement.
Endocarditis may become apparent as with fever, petechiae, and, occasionally, embolic complications.
Serratia Marcescens CausesThe chief risk factor for S. marcescens infection is long-drawn-out hospitalization. Those who have a weak immune mechanism are more prone to the development of these nosocomial infections. Important triggering factors include: intra peritoneal, intra venous or urinary catheters, instrumentation of the respiratory tract, such as bronchoscopy and ventilators, intra articular injections, trauma to the skull, neuro-surgery, epidural injection, or a lumbar puncture.
Serratia Marcescens TreatmentThe principal treatment plan is administering anti biotics.
Abscesses and exudates call for incision and drainage.
S. marcescens is resistant to ampicillin, macrolides, and 1st generation cephalosporins. Consequently, most doctors manage the case with aminoglycosides along with anti-pseudomonal beta-lactam. Also, quinolones are decidedly active against most Serratia strains.
Definitive therapy for the case depends on the results of vulnerability testing, given that, multi-resistant strains are rather common.
Home therapy is an alternative for those patients who are clinically stable; others have to be hospitalized.
The prognosis for S. marcescens infections is moderately poor. Certain infections, such as UTIs, abdominal abscesses and arthritis show fairly good outcomes; whilst meningitis, cerebral abscesses, sepsis and endocarditis show moderate prognosis.