Inflammation
localized protective reaction of tissue to irritation, injury, or
infection, characterized by pain, redness, swelling, and sometimes
loss of function.
Abscess formation and causes
an infection with bacteria
Pus forming
Causes: staphylococcal bacteria
Virulence factors of Streptococcus pyogenes
M protein is important virulence factor, helps avoid phagocytosis by
breaking down complement protein C3b
Virulence factors of Clostridium tetani
A-B toxin
Virulence factors of Vibrio cholera
ToxT
Virulence factors of Staphylococcus aureus
Multiple virulence factors play role in wound infections
Clumping factor, other proteins allow
attachment Lipases, proteases, hyaluronidases damage
tissue Capsules, coagulase, protein A protect from
attack by complement system, phagocytes, antibodies
Virulence factors of Neisseria gonorrhoeae
Fimbriae or pili
Vaccine available (if any) against pneumonia
pneumococcal polysaccharide vaccine (Pneumovax)
Most common causative agent of bacterial pneumonia
S. aureus, S. pneumoniae
STD
Sexually Transmitted Disease
blood-borne infection
HIV, hepatitis B and viral hemorrhagic fevers
bacterial meningitis in adults and in children
Adults: Streptococcus pneumoniae (pneumococcus) and
Neisseria meningitidis (meningococcus)
Children: Group B streptococcus,Escherichia coli
subacute bacterial endocarditis
Staphylococcal Wound Infections
Staphylococcus epidermidis multiple tissue
abscesses in immunocompromised individuals
S. aureus, S. epidermidis are Gram-positive
cocci
Trauma and wound infections
Clostridial Myonecrosis (Gas Gangrene)
Rabies: causative agent
transmission
signs/symptoms
causative agent:
Rabies virus, member of rhabdovirus family
Has striking bullet shape, is enveloped, contains
single-stranded, negative-sense RNA
transmission:
Transmission via saliva from bite of rabid
animal Inhalation of aerosols containing virus (e.g.,
from bat feces) has been reported but not documented
signs/symptoms:
Fever, head and muscle aches, sore throat, fatigue,
nausea Tingling or twitching sensation at site of viral
entry
Wound healing and wound infections
Prompt surgical removal of all dead and infected
tissue Antibiotics, hyperbaric oxygen treatment
No available vaccine Begins with outgrowth of
connective tissue (fibroblasts) and capillaries from surface to
yield granulation tissue
Fills space created by wound
Shrinks, is converted to collagen (scar tissue)
Covered by skin or mucous membrane
HIV infection: causative agent, HIV structure, transmission, host cells
Causative Agent:
human immunodeficiency virus type 1 (HIV-1), an
enveloped, single-stranded RNA virus of retrovirus family
HIV Structure: an enveloped, single-stranded RNA virus of
retrovirus family
Transmission:
Needle-exchange programs Identifying,
treating other STIs Consistent condom use
Circumcision can reduce incidence up to 60% during
pregnancy, passage through birth canal, and breast-feeding
Host Cells:
helper T (TH) cells that have CD4
surface proteins
HIV Signs/symptoms
6 days to 6 weeks
flulike: fever, head and muscle aches, enlarged lymph
nodes.
HIV Testing
antibody screening test (immunoassay), which tests
for the antibodies that your body makes against HIV.
relationship between HIV and AIDS
Most cases caused by human immunodeficiency virus
type 1 (HIV-1), In parts of western Africa, HIV-2 is
common cause of AIDS
Role of bacterial toxins in the development of intestinal infections
Attachment often prerequisite, typically adhesins on pili
Transmission of intestinal pathogens
fecal-oral route commonly from food or water contaminated with
animal or human feces
role of water quality and water treatment in this process
Oral rehydration therapy (ORT) used to counteract loss of fluid
and electrolytes from diarrhea � Water alone insufficient; cannot be
absorbed quickly � Glucose increases absorptive capacity of
intestine � Oral rehydration salts (ORS) is glucose plus sodium
chloride, potassium chloride, trisodium citrate
Cholera: causative agent, transmission, signs/symptoms, pathogenesis
causative agent: Vibrio cholerae: curved, Gram-negative rod � Several
serotypes grouped by O antigen -O1 is current serotype usually
circulating � Halotolerant, can grow in alkaline conditions
Transmission: Fecally contaminated water most common source Foods
including crab, oysters, vegetables implicated
Signs/Symptoms:
severe watery diarrheal disease Can amount to 20
liters/day Has �rice water stool� appearance
Vomiting may occur at onset; severe muscle cramps result from
loss of fluids and electrolytes Severe dehydration can lead
to organ failure and death
Pathogenesis:
� Sensitive to acid, so large numbers must be ingested
� Adhere to epithelial cells of small intestine, establish
infection, produce cholera toxin, an A-B toxin
Plague: causative agent, transmission, signs/symptoms, pathogenesis
Causative Agent: Yersinia pestis: like other
Enterobacteriaceae, a facultative anaerobe, Gram-negative rod (safety pin)
Transmission: transmit via saliva, Flea that live on Prairie dogs,
rock squirrels, their fleas main reservoir, Respiratory droplets
produced by coughing can spread
Signs/Symptoms: 2�6 daysEnlarged and tender lymph nodes buboes;
bubonic plague High fever, shock, delirium, patchy bleeding under skin
Pathogenesis:
Multiple virulence factors allow it to avoid host
defenses Some on bacterial chromosome, others on 3
plasmids Protease (Pla) clears lymphatics and capillaries
of clots, inactivates certain complement system components, C3b
and C5a
-Streptococcus pyogenes (Abscess/ wound/ respiratory)
Pathogenesis: M protein important adhesion, Protein F adheres to
fibrin of epithelial cellsDNase, hyaluronidase, proteases degrade
intracellular connections
respiratory droplets or contaminated food Nasal
carriers more likely to spread than pharyngeal Anal
carriers uncommon; can be source of healthcare-associated
infections
Confirmation via diagnostic tests and throat
culture Treatment with penicillin or erythromycin
about 90% effective; prevents post-streptococcal sequelae
S. aureus, S. epidermidis (Skin/ Abscess/ wound)
Clumping factor, other proteins allow
attachment Lipases, proteases, hyaluronidases damage
tissue Capsules, coagulase, protein A protect from
attack by complement system, phagocytes, antibodies
S. aureus, S. epidermidis are Gram-positive
cocci
S. aureus carriers at increased risk for surgical wound
infection Age, poor general health, immunosuppression,
prolonged preoperative hospital stay, infection at other site
all factors
S. epidermidis found on skin and mucous membranes as
part of normal microbiota on most people
Vancomycin-intermediate S. aureus (VISA) and
vancomycin-resistant S. aureus (VRSA) have emerged
Thorough cleaning of wounds reduces infections
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Signs and Symptoms:
Initially, difficulty swallowing, jaw muscle
contractions Then continuous, painful,
uncontrollable muscle spasms Breathing becomes
difficult, abnormal heart rhythms may occur, bones can
fracture Following period of almost unbearable
pain, person often dies of pneumonia or from
Causative Agent:
Clostridium tetani: anaerobic,
Gram-positive
Pathogenesis: Not invasive; colonization
localized to wound A and B toxins Plasmid
Encoded
Prevents release of neurotransmitter from inhibitory
neurons, so muscles contract without control
Puncture wounds including stepping on a nail, body
piercing, tattooing, animal bites, splinters,
injected-drug Treatment and
Prevention: Human tetanus immune globulin (TIG)
injection Cleaning wound, antibiotics, vaccine
-Pseudomonas aeruginosa (Abscess/ wound)
Signs/Symptoms:
Chills, fever, skin lesions, shock
Causative Agent
Pseudomonas aeruginosa is Gram-negative rod with polar
flagellum
Found in soils, water
Pathogenesis:
Tissue damage delays healing, increases risk of
septic shock nature, grows in
most places that have moisture Soaps, ointments,
eyedrops, contact lens solutions, cosmetics, disinfectants,
swimming pools, hot tubs, even distilled water
Introduced into hospitals on ornamental plants, flowers,
produce; also found on hospital equipment, inner soles of
shoes, illegal injectable drugs
Treatment:
Only a few antimicrobial medications effective
Eliminating possible sources; removing dead tissue