the most common producers of ESBL. Klebsiella spp is the most common producer of carbapenemases but it may be produced by E. Coli, Enterobacter spp, Pseudomonas spp and salmonella. Amp C B-lactamases are seen in the following bacteria: Serratia, pseudomonas, Acinetobacter, citrobacter, enterobacter. Other mechanisms of resistance include a change in the cell wall permeability which prevents the entry of antibiotics. Some bacteria will develop an altered structural target for antibiotics. Other bacteria may have an altered metabolic pathway that bypasses the reaction inhibited by the drug. Or the bacteria may have developed an altered enzyme that can still perform its metabolic function but is much less affected by the drug. Occurs when bacteria change in a way that reduces the effectiveness. Bacteria survive and continue to multiply, causing more harm Discuss the role of vaccines in preventing infectious disease. Purpose of vaccination is to induce active immunologic protection before exposure to the risks of infection, produces large number of memory cells, and a sustained protective secondary immune response May need booster injections to maintain protection throughout life Need desired protective immune response (ie: antibody, T cell), identifying the appropriate antigen to induce that response (ie: immune responses against some antigens on an infectious agent are ineffective or even increase the risk for infection), determining the most effective route of administration, optimizing the number and timing of vaccine doses to induce protective immunity in a large proportion of the at-risk population
Pathological Effects Properties Staphylococca l Gram positive (commonly causes hospital acquired infections in skin and soft tissue infections) -Part of normal flora, can be transmitted through direct contact (direct hand contact, stethoscopes) -Found on nares & skin Has surface proteins which enable it to attach to endothelium and tissues to cause infection -Produces Protein A which binds with the IgG antibody, masks the bacteria from the antibody -Produces coagulase (produces clotting on the exterior portion of the bacteria, provide protection from complement mediated lysis) -MRSA- resistant form of bacteria (conferred from B-lactamase) D/t recent antibiotic use (cephalosporin, fluoroquinolones, prolonged hospitalization, nursing home residents, invasive medical devices, dialysis E. coli *Most significant enteric bacteria, disease causing in many different organs (diarrhea, hemolytic uremic syndrome, common cause of UTIs) -Gram negative rod, part of normal flora in the gut -Enteropathogenic E. colic (EPEC)- causes diarrhea in infants, usually in developing countries -Enterotoxigenic E. coli- traveler’s diarrhea, diarrhea in infants in developed countries -Shiga toxin producing E. coli (STEC)- produces a toxin that has been associated with hemorrhagic colitis **newborns highly susceptible because they lack IgM antibodies **leading cause of meningitis in infants Candida Most common fungal infection in humans, part of normal flora
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- Fall '15