Klebsiella spp is the most common producer of

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