Feb 2007 Dr W Lowman THE BASICS OF CLINICAL RELEVANCE
Feb 2007 Dr W Lowman Objectives 1. Correlate the physicochemical properties of the gram-negative cell wall, with the clinically relevant pathogenetic and virulence factors of gram-negative bacteria List the key differences between the gram-positive and gram-negative cell wall. 3a. Understand the complexity of the interaction between the cell wall and antimicrobials. 3b. Relate this interaction to the clinical phenomenon of antibiotic resistance.
Feb 2007 Dr W Lowman G- cell wall Cytoplasmic membrane Periplasmic space Peptidoglycan Outer membrane -LPS
Feb 2007 Dr W Lowman
Feb 2007 Dr W Lowman Nomenclature Family- Enterobacteriaceae Genus- Escherichia; Escherichia Species- coli; coli Pseudomonas aeruginosa Klebsiella pneumoniae
Feb 2007 Dr W Lowman ID principles Based on phenotypic criteria in routine clinical laboratory. - growth characteristics; cell morphology & staining; biochemical reactions; serological reactions Molecular methods more precise but primarily used for taxonomic purposes. - G+C% content; DNA-DNA hybridization; 16S rRna
Feb 2007 Dr W Lowman Bacteria & oxygen (O 2 ) Obligate AnO2 Obligate Aerobe AerotolerantMicroaerophile Faculatative Anaerobe ABILITY TO TOLERATE & GROW IN PRESENCE OF OXYGEN (ENERGY- OXYGEN USED AS TERMINAL ELECTRON ACCEPTOR) StrictModerate SPECTRUM
Feb 2007 Dr W Lowman
Feb 2007 Dr W Lowman Clinical spectrum Community-acquired Nosocomial-acquired Infections Not always clear-cut. Term ONSET may be more appropriate “Healthcare-associated infection”
Feb 2007 Dr W Lowman Community-acquired GIT infections- diarrhoeal illness -Salmonella, Shigella, E.coli, Yersinia -Outbreaks NB!
Feb 2007 Dr W Lowman Community-acquired Urinary tract infections -E.coli -Proteus spp. Lower respiratory tract infections Wound/ SSTI
Feb 2007 Dr W Lowman Nosocomial infections ANYTHING NB! in terms of antibiotic resistance. Most resistant organisms typically found in this group. Empiric treatment becomes an important challenge and requires informed guesswork. Pathogen(s) Antibiotic susceptibilities
Feb 2007 Dr W Lowman Antibiotic resistance β-lactams Enzymes Penetration Binding
Feb 2007 Dr W Lowman ANTIBIOTICS ARE NOT THE ANSWER!
Feb 2007 Dr W Lowman