Acinetobacter Species Family Moraxellaceae Genus Acinetobacter Species A

Acinetobacter Species • Family : Moraxellaceae • Genus : Acinetobacter • Species: A. baumannii (19 biotypes) A. calcoaceticus A. iwoffi A. johnsonii A. haemolyticus A. radioresistens Introduction: • Acinetobacter species is a ubiquitous pathogen. • It capable of causing both community and health care–associated infections. • This organism has emerged recently as a major cause of Hospital Acquired Infection because of the extent of its antimicrobial resistance. • Acinetobacter, comes from the Latin word for "motionless, " because they lack cilia or flagella with which to move.

Morphology & general Characteristic features • It is Strictly aerobic bacteria • Gram negative coccobacillus. • Encapsulated and Nonmotile • Growth occurs in 370 C. • It is not a part of normal human flora. Virulence factor • The presence of a polysaccharide capsule formed of L-rhamnose, D-glucose, D-glucuronic acid, and D-mannose, which probably renders the surface of strains more hydrophilic. • Polysaccharide capsule, prevent complement activation, delay Phagocytosis. • The property of adhesion to human epithelial cells in the presence of fimbriae.

• The potentially toxic role of the lipo-polysaccharide component of the cell wall and the presence of lipid A. • Pilli is involved in the initial surface attachment during biofilm formation. Pathogenesis • Hospital Acquired Pneumonia • Ventilator – associated Pneumonia • Urinary tract Infection • Bloodstream Infection • Meningitis and Ventriculitis • Skin / wound/Bone Infection • Endocarditis • Peritonitis in peritoneal dialysis patients • Endopthalmitis and Periorbital Cellulitis

Laboratory Diagnosis Specimen – Pus, Pus swab and Tissue debridement. Collection – Specimen collect in Sterile container and transport to the Laboratory within 2 hrs. Direct Gram stain- Gram negative coccobacilli and Pus cells Culture – • Nutrient agar – Smooth, mucoid, greyish white colonies, 2 -3 mm in diameter & Nutrient broth – uniform turbidity • Mac. Conkey agar – Non-lactose fermenting, smooth 2 -3 mm colonies • 5% Sheep Blood agar– usually Non-hemolytic. • Gram stain - Gram negative coccobacilli • Oxidase test - Negative • Selctive media – Leeds Acinetobacter, CHROM & Herellea Agar, Holton’s Agar

Biochemical Reaction Indole, H 2 S, Urease – Not Produce Molecular method: -PCR -16 Sr. RNA ribosomal DNA restriction analysis. Test Result A. baumannii A. iwofii Oxidase Negative Catalase Positive TSI Alk/No change Simmon’s Citrate Utilize Variable Glucose Positive Negative Xylose Positive Negative Lactose Positive Negative