WOUND INFECTIONS

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• WOUND INFECTIONS

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• Wound infections and abscesses can occur in
  different places.
• Some are present at surgical or wound sites
• Others are internal
• Several virulence factors are involved
• Staphylococcus aureus is a common cause

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Anal gland abscess
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Pulmonary abscesses
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Staphylococcal wound infections

• Cause Staphylococcus aureus (leading cause) and
  S. epidermidis,
• The presence of sutures predisposes a
  post-surgical patient to these infections.
• Dx culture and isolation
• Tx debridement and antibiotics
• Prevention care not to infect patients during or
  after surgery, handwashing, and cleaning of wounds

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Surgical wound infection
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Dog with wound infection
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Wound infection
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Infections of burns (nosocomial)

• Cause - primarily Pseudomonas aeruginosa
• Infections of burns by this organism are a
  leading cause of death in burn patients. The
  bacterium can invade the bloodstream. It
  produces tissue damage, prevents healing, and
  increases the risk of septic shock
• Dx - culture and isolation, also P. aeroginosa
  results in pigmentation and a characteristic odor
• Tx - antibiotics, but difficult because of
  resistance
• Prevention - handwashing and care not to expose
  the patient, prompt cleaning of wounds, sulfur
  compounds

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Burn infections- often caused by Pseudomonas
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Gas gangrene

• Cause - Clostridium perfringens
• Gangrene (AKA anaerobic cellulitis or
  myonecrosis) is now relatively rare. Exotoxins
  produce RBC lysis, edema, and tissue destruction.
  A mild form does not spread however, a true
  myonecrosis is very destructive and capable of
  spreading to adjacent healthy tissues.
• Dx - symptoms and Gram stain
• Tx - removal of tissues (sometimes amputation),
  hyperbaric oxygen treatment, and antibiotics
• Prevention prompt cleaning of wounds

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Gas Gangrene caused by Clostridium perfringens
(an anaerobe)
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Necrotizing fasciitis

• Cause- Streptococcus pyogenes
• This rapidly spreading disease can lead to death
  in a relatively short time.
• DX- culture and symptoms
• TX- removal of infected tissues and amputation if
  necessary. Antibiotics
• Prevention- prompt cleaning of wounds

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Necrotizing Fasciitis in Jake Finkbonner
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Jake Finkbonner after having the infection
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• There are other types and causes of wound
  infections that are included in your text if you
  are interested
• Lumpy jaw
• Cat Scratch Disease
• Rat bite fever
• Fungal wound infections

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• Infections of the Blood and Lymphatic System

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Subacute Bacterial Endocarditis

• Cause - normal flora of the mouth and skin (e.g.,
  streptococci and Staphylococcus epidermidis)
• Predisposing factors include congenital defects
  of the heart and diseases such as Rheumatic
  fever. Usually the valves are affected.
  Symptoms include fatigue and slight fever. The
  disease progresses slowly.
• Dx - blood cultures in some, but some rare
  organisms are harder to identify
• Tx antibiotics
• Prevention - prophylactic antibiotics (e.g., for
  oral surgery), sterile technique when using IV
  catheters

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Subacute Bacterial Endocarditis
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Acute Endocarditis

• Cause - Staphylococcus aureus, Streptococcus
  pneumoniae
• This infection is more severe and progresses more
  rapidly than does subacute bacterial
  endocarditis. The bacteria are more virulent and
  drug addiction is a predisposing factor.
• Dx- blood cultures
• Tx antibiotics
• Prevention- avoid illegal drugs and sharing
  needles

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Acute Endocarditis
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Bacterial endocarditis

• Prevention If you have heart-valve damage or a
  heart murmur Request antibiotics prior to
  medical procedures that may introduce bacteria
  into the blood. These include dental work,
  childbirth and surgery of the urinary or
  gastrointestinal tract. It is also important to
  maintain good oral hygiene. Consume alcohol in
  moderation. Don't use illicit drugs like heroin
  or cocaine. Consult medical professional before
  becoming pregnant

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Septicemia

• Cause - a variety of bacteria including Gram
  and Gram organisms as well as some fungi
• Septicemia is an infection of the blood and is
  very serious. For example, the mortality rate
  for septicemia cause by Gram - bacteria is 30-
  50. The infection usually originates elsewhere
  (e.g., a boil or pneumonia). Symptoms include
  violent chills, fever, anxiety, and rapid
  breathing.
• Dx - blood cultures
• Tx antibiotics
• Prevention - avoid contamination of the blood.

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Septicemia
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Tularemia

• Cause - Francisella tularensis
• AKA rabbit fever. There are 150-200 cases/year.
  The bacterium is one of the most infectious but
  is not transmitted from person to person. The
  symptoms vary but may include skin lesions,
  swollen lymph nodes, diarrhea, cv or pulmonary
  disease. Mortality varies but can be up to 30
  (for the pneumonic form).
• Dx - culture on special media, and antibodies
• Tx antibiotics
• Prevention - vaccination for high risk, avoiding
  insect vectors, and care when skinning rabbits

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Tularemia
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Plague or Black Death.

• Cause - Yersinia pestis
• Plague is endemic in the US(2-40) cases per
  year. It killed 1/3 of the population of Europe
  between 1346 and 1350. Persons at highest risk
  in the US are vets, campers, backpackers, and
  people living near woodlands and forests.
  Manifestations include bubonic plague where the
  bacteria multiply in a flea bite, causing the
  formation of a bubo (a hard painful nodule)
  followed by chills, fever, headache, nausea,
  malaise, weakness, and tenderness of the bubo.
  This may progress to septicemic plague causing
  DIC, circulatory stagnation, subcutaneous
  hemorrhage, and gangrene (causing darkening of
  the skin, hence the name Black Death). Pneumonic
  plague is highly contagious. Untreated mortality
  rate from 50 to almost 100.
• Dx - culture and isolation, symptoms
• Tx - antibiotics ASAP, quarantine
• Prevention - avoid fleas and a temporary vaccine
  for high risks

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Bubonic form
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Septicemic form
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Pulmonary form
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Prevention in the past
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Areas affected in the U.S.
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• A total of 18,739 human cases were reported from
  20 countries to the World Health Organization
  between 1980-1994. Plague is most likely
  under-reported because of inadequate surveillance
  and laboratory capabilities in some countries. In
  the United States, plague is endemic in the
  western states. From 1980-1998, human cases in
  the United States have averaged 13 per year, with
  a high of 40 cases in 1983. The case fatality was
  about 15. Thirty percent of cases have occurred
  among Native Americans living in the southwestern
  states, where plague is enzootic. Plague
  pneumonia, potentially transmissible by the
  person-to-person route via respiratory droplets,
  has occurred in 11 of cases in the United States
  between 1979-1997. Five of seven persons who were
  infected by inhalation were known to be exposed
  to infected domestic cats. The presence of plague
  in co-existing suburban and rural rodent
  populations on the outskirts of some southwestern
  and Pacific Coast cities underscores the risk of
  epidemic plague in the United States in the
  absence of effective surveillance and prevention.
  Most plague cases in the United States occur in
  the summer months, when the risk for exposure to
  infected fleas is greatest. The majority of cases
  are acquired in or near the patient's residence.
  Risks for acquiring the disease are associated
  with conditions that provide food and shelter for
  plague-susceptible rodents near human dwellings

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Tetanus or Lockjaw

• Cause - Clostridium tetani
• Spores gain entry through a puncture wound,
  burns, umbilical stumps, and rarely medical
  procedures. In the US, there are approximately
  30-60 cases each year with a 25 fatality rate,
  but tetanus accounts for several hundred thousand
  infant deaths per year in third world countries.
  A potent neurotoxin is produced which blocks the
  release of neuroinhibitors that are necessary to
  the regulation of muscle contractions. Symptoms
  include (in order of appearance) clenching the
  jaw, arching the neck, flexion of the arms and
  extension of the legs
• Dx - cultures are of limited value, symptoms and
  toxin
• Tx - antitoxin, antibiotics, and cleaning of
  wounds
• Prevention vaccination.

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Neonatal tetanus is one of the leading causes of
death worldwide
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• Viral and Protozoan infections

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Infectious mononucleosis or the Kissing Disease

• Cause - Epstein-Barr virus.
• Symptoms include fever, sore throat, and
  enlargement of the spleen and lymph nodes of the
  neck. Complications include myocarditis,
  meningitis, hepatitis, or paralysis. Spread by
  saliva.
• Dx serology
• Tx - usually not needed
• Prevention - avoid other peoples saliva

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Mono
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Atypical lymphocytes
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Yellow fever

• Cause - an arbovirus spread by mosquitoes
• The symptoms of yellow fever vary. Mild disease
  is characterized by fever and a slight headache.
  A more severe form results in high fever, nausea,
  bleeding from the nose and into the skin, black
  vomit and jaundice. Mortality can be as high as
  50.
• DX blood test
• Tx symptoms
• Prevention - avoid mosquitoes and using
  insecticides

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Yellow fever
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Malaria

• Cause - Plasmodium vivax, P. falciparium, P.
  malariae, and P. ovale
• Malaria is one of the most significant diseases
  worldwide. The vector is the Anopheles mosquito.
  Mortality is about 1 million per year and 41 of
  humans live in areas where these organisms are
  endemic. The symptoms reoccur and coincide with
  the simultaneous rupture of rbcs and include
  bouts of chills, fever, and sweating with
  complications such as anemia, enlargement of the
  spleen, liver, and kidneys, pulmonary failure and
  CNS and GI involvement. Morbidity is 300-500
  million infected worldwide and currently a child
  dies every 20 seconds from malaria.
• Dx - presence of the parasites in the blood,
  serological tests
• Tx - antiparasitic medicine
• Prevention - vector control

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Top infectious killers 2004

• http//www.globalhealth.org/view_top.php3?id228