Serratia Serratia marcescens • Gram negative rod • Enterobacteriaceae • Found in various ecological niches soil water plants animals • Survives under extreme conditions disinfectants and antiseptics distilled water salt water • Produces characteristic red pigment, prodigiosin Serratia sp. • water & soil • Serratia marcescens – produces a red pigment, prodigiosin; causes pneumonia, burn & wound infections, septicemia & meningitis • Serratia marcescens – nosocomial surgical wound infections, UTI, RTI, septicemia Serratia -Common opportunistic pathogen in hospital pts. -Cause pneumonia, bacterimia, endocarditis. -Often resist to aminoglycosides and penicillin. -Treatment-Third generation Cephalosporines. Seratia • The main risk factor for Serratia sepsis/bacteremia is hospitalization • Known to cause bacteremia, UTI, respiratory tract infection, meningitis, endocarditis, osteomyelitis, cutaneous infections, and ocular infections. • Serratia infections should be treated with an aminoglycoside plus an antipseudomonal beta- lactam. Most strains are susceptible to amikacin. Reports indicate increasing resistance to gentamicin and tobramycin. Quinolones also are highly active against most strains. • Definitive therapy should be based on the results of susceptibility testing because multiresistant strains are common Serratia marcescens Infection Issues • Transmission on hands of staff most important mode of spread • Occasional focal environmental source • Infection usually occurs in compromised patients: • Pneumonia in ventilated patients • UTI in catheterised patients • Post-operative wound infections • Blood stream infection in patients with intravenous access devices Published S. marcescens Nursery Outbreaks – implicated sources • Liquid theophyline • Milk from used bottles • Ventilator equipment • Breast pumps • Enteral feed additives • Emolient skin cleansers • Antiseptic soaps • Suction tubing • Disinfectants Serratia marcescens Clinical Presentation • Bacteraemia / septicaemia • Meningitis • ventriculitis, cysts • cell count may be normal • mortality 40% • Pneumonia • Urinary tract infection • Soft-tissue infection • Overall mortality 14% S. marcescens Nosocomial Infections • United States CDC-NNIS* • 2.0% of blood stream infections • 2.8% of surgical site infections • 3.6% of pneumonia * All age groups Infection Control Recommendations for Level III Nurseries • Cohort colonised babies – Weekly screening of non-colonised babies • Meticulous hand hygiene practices • Gowns & gloves for all patient contact likely to produce contamination Infection Control Recommendations for Level III Nurseries • Do not move equipment between rooms • Equipment may need to be decontaminated with 500ppm hypochlorite • Limit room access to essential personnel • Effective discharge planning • Communication and Education Identification characteristics of seratia marcescens(Unknown) Test reaction Pigment _ Oxidase _ KIA K/A TSI A/A Indole _ MR _ VP + citrate + urease _ LIA +(k/k) Arginine _ ornihtine + Motility + ONPG + DNase + Gelatinase + Fermentation of Arabinose _ .