Chapter 9- Reporting Flashcards
Includes initiation of the infectious process and the mechanisms that
lead to the development of signs and
symptoms of disease.
pathogenesis of bacterial infection
Bacteria sticking to host cell surfaces, a
crucial initial step in infection
adherence
: Asymptomatic individual capable of
transmitting infection to others.
carrier
Multiplication of infectious agents within
the body, excluding normal microbiota.
infection
Entry of pathogens into host cells or tissues,
spreading in the body.
invasion
Normal microbial flora in healthy
individuals
microbiota
Microorganism not causing disease,
possibly part of microbiota.
nonpathogen
Causes disease when host
resistance is compromised.
opportunistic pathogen
: Microorganism capable of causing disease
pathogen
Infectious agent’s ability to cause
disease.
pathogenicity
Toxins stimulating massive cytokine
production by T cells
superantigen
Microorganism’s ability to produce
toxins contributing to disease.
toxigenicity
: Agent’s quantitative ability to cause
disease; involves adherence, persistence, invasion, and toxigenicity.
virulence
postulates provide guidelines for
establishing infectious disease causation, though exceptions exist
Robert Koch
offers new tools to study
pathogenic bacteria, including molecular cloning for
isolating and modifying virulence genes.
modern microbial genetics
amplifies microorganism-specific nucleic acid sequences from
host tissues, aiding identification
polymerase chain reaction (PCR)
adapt to various environments, including
those within and outside hosts, enhancing survival and transmission
bacteria
species transmitted through food, and Yersinia pestis via fleas from rodents
salmonella and campylobacter
contaminates water sources, while
Mycobacterium tuberculosis spreads through
respiratory aerosols.
vibrio cholerae’s voluminous diarrhea
is common for many bacteria,
with nosocomial infections often spread by hospital personnel. Handwashing is vital for infection control.
hand transmission
typically enter the body through
mucous membranes or damaged skin, where normal defenses are overcome for infection to occur.
pathogenic bacteria
typically begin with bacteria attaching to
host cells, often epithelial cells, establishing a primary site of infection.
infections
enables bacteria to disseminate throughout the body and
colonize tissues conducive to their growth
bacteremia
For instance, pneumococcal pneumonia
starts when Streptococcus pneumoniae,
commonly found in the ______________ of
healthy individuals, is aspirated into the lungs.
nasopharynx
_____________ can enter the
bloodstream, causing bacteremia in 10-20% of
cases, potentially spreading to secondary sites
like cerebrospinal fluid, heart valves, and
joints, resulting in complications like
meningitis and endocarditis.
Pneumococci
are genetic elements in
bacterial genomes associated with virulence. They typically have different guanine plus cytosine (G + C) content, are often linked to tRNA genes and mobile
genetic elements, and exhibit genetic instability
pathogenicity islands
which contribute to
urinary tract infections, and Salmonella serotype Typhimurium SPI-1, involved in cell invasion and
diarrhea.
E. coli PAI 1536 and II536
Regulation of bacterial virulence factors is complex and influenced by environmental signals like
temperature, iron availability, and pH
adjusts expression of virulence factors
based on temperature, crucial for adapting to the host
environment.
yersinia pestis
is crucial for bacteria in their environmental
niches, although not always in disease pathogenesis.
motility
are motile at lower temperatures but lose motility at host temperature, indicating adaptation to different
environments.
yersinia enterocolitica and listeria monocytogenes
the ability to cause infection and disease.
bacterial virulence
is a critical step in the
infectious process for many pathogens.
bacterial invasion
adhere to and invade
host cells by inducing actin polymerization, leading to the formation of pseudopods and subsequent engulfment
shigella species
Listeria monocytogenes
adheres to and invades intestinal cells, facilitated by proteins called ______________
internalins
employs a similar
adherence-invasion process
Yersinia enterocolitica
induces coiling phagocytosis
in pulmonary macrophages.
Legionella pneumophila
utilizes pili and opacity-associated proteins (Opa) to adhere to and invade host
cells
Neisseria gonorrhoeae
which is present in the outer membrane of gram-negative rods
endotoxin
produced by both gram-positive and gram-negative bacteria, are medically significant due to their
role in various diseases.
exotoxins
derived from modified
exotoxins, have been pivotal in disease prevention
toxoids
aids in host cell adherence and
entry
B subunit
provides toxicity
A subunit
secretes diphtheria toxin,
inhibiting protein synthesis by modifying peptide chain elongation factor EF-2
C. diphtheriae
produces a highly potent toxin
that inhibits acetylcholine release, causing
flaccid paralysis
C. botulinum
results from various necrotizing
toxins damaging cell membranes and tissues.
C. perfringens
often associated with diarrheal diseases,
are a significant concern due to their impact on public health.
Enterotoxins
a cause of cholera, produces an
enterotoxin that leads to life-threatening diarrhea through increased adenylate cyclase activity and cAMP concentration in intestinal cells
V. cholerae
Gram-negative bacteria release lipopolysaccharides (LPS), also known as ___________, when they lyse.
endotoxins
The pathophysiological effects of LPS include
- Fever
- Leukopenia
- hypotension,
- shock, intravascular coagulation,
- organ dysfunction.
occurs early, coinciding
with fever onset, and is followed by leukocytosis.
LPS-induced leukopenia
occurs early in gram-negative bacteremia or after injection of LPS.
Hypotension
is a frequent complication of gram-negative bacteremia and can also occur in other infections
Disseminated intravascular coagulation
the first step of the intrinsic clotting system—
and sets into motion the coagulation cascade, which culminates in the conversion of fibrinogen to fibrin
Hageman factor
is made up of crosslinked macromolecules that surround the bacterial.
peptidoglycan of gram-positive bacteria
produces collagenase, which breaks
down collagen and facilitates the spread of infection in tissues
C. perfringens
secretes coagulase, which, along with
blood factors, induces plasma coagulation, forming fibrin walls around lesions and protecting bacteria
from phagocytosis
S. aureus
produced by various bacteria, degrade hyaluronic acid, aiding in
tissue penetration
Hyaluronidases
which activates plasma proteolytic enzymes,
promoting fibrin clot dissolution and bacterial spread.
streptokinase
is the predominant antibody
on mucosal surfaces, existing in two primary forms: IgA1 and IgA2
immunoglobulin A
serves as a key virulence factor for these pathogens, enabling them to evade the host’s mucosal immune defenses
IgA1 protease
is vital for the growth and metabolic processes of most microorganisms, serving as a cofactor in various enzymatic reactions
iron
requires iron as an essential
virulence factor.
Pseudomonas aeruginosa
is widespread and affects
numerous organ systems, including the immune system.
Human iron deficiency
can impair cell-mediated
immunity and reduce polymorphonuclear cell function, predisposing individuals to infections
Iron deficiency
m is a cluster of bacteria attached to surfaces
or each other, encased in an exopolysaccharide matrix.
biofilm
are shielded from the host’s immune
response by the exopolysaccharide matrix and can resist some antimicrobials due to diffusion barriers.
biofilm bacteria
cause disease through the elaboration of factors that facilitate adherence, persistence, invasion, and toxigenicity.
virulent bacteria
are rodlike or hairlike structures, respectively, that facilitate attachment to host cells.
Pili and fimbriae
is a complex mechanism that involves elaboration of proteins that facilitate entry
invasion of host cells
