Bacteria 3 (Lecture 6)

Sepsis

-Mediators of inflammation into the bloodstream caused by an infection (systemic inflammatory response syndrome)

Septicemia

-Presence of pathogenic microorganisms or their toxins of their toxins in the blood

Puerperal Fever (puerperal sepsis) (systemic diseases)

-Caused by Streptococcus pyogenes

-After vaginal delivery, the uterine wall becomes irritated and organisms can enter this site and eventually get into the blood stream

-Antiobiotics

Group B Streptococci (GBS) (systemic diseases)

-Streptococcus agalacitae causes neonatal sepsis with meningitis as a potential complication

-Baby becomes contaminated through birth canal

-Mothers are now checked for the organism before labor so they can be treated with antibiotics to prevent this complication in the newborn

Rheumatic Fever (systemic diseases)

-Streptococcus pyogenes causes “Strep throat”, once these symptoms go away, a complication of fever, rash, and arthritis can develop

-Heart damage can be another complication due to antibodies made against the organism (M protein) reacting to heart protein

-Antibodies are considered cross-reactive since they recognize protein on the organism as well as on heart muscle

Anthrax (systemic diseases)

-Bacillus anthracis causes this infection

-Endospores are eaten from contaminated food or breathed in

-Three forms: cutaneous, respiratory, and intestinal

-Plasmids carry genes for 3 EXOTOXINS (edema factor, lethal factor, and protective antigen) and capsule formation

*all traits must be present to cause disease

-Exotoxins inhibit macrophages from destroying the organism and interfering with other parts of our immune system

-Blood clots in lung capillaries and septic shock will cause death

-Prevention by VACCINATION and people working with animals and animal parts (skins) must keep the working area clean since endospores can be contaminating fur of animals

Gangrene (systemic diseases)

-Clostridium perfringens organism is an endospore former anaerobe

-Since the organism is an anaerobe, it will grow deep in tissue where oxygen is not available and the infection ultimately cuts off the blood supply (ischemia)

-Makes toxins and enzymes to destroy host cells and the bacteria will eventually enter the bloodstream

-Death will occur if infection isn’t treated

Plague (systemic diseases)

-Yersinia pestis makes exotoxins which inhibits macrophages and other parts of the immune system

-Survives in macrophages

-Found in wild rodents which can be bitten by a flea, and now the flea can bite a human and transfer the organism

-Organism travels through the lymph tissue and the swollen lymph tissues are often referred to as “buboes”

-If organism gets into bloodstream, it can cause “pneumonic plague” which spread directly to other humans and is lethal

-Vaccine is available

Lymes Disease (systemic diseases)

-Borrelia burgdoferi causes this disease

-Deer and rodents are the source of the organism and ticks can transfer the organism from them to humans

-The '“Bulls Eye Rash” is a telltale sign of the disease, but not everyone gets it

-Early antibiotic treatment is necessary to prevent complications such as nerve damage and arthritis

Rickettsial system disease (systemic diseases)

-Caused by gram-negative obligate intracellular parasites

-Considered emerging diseases since there is a growing number of new rickettsial diseases being discovered

-The different organisms invade and damage blood vessel linings

-Leakage from the blood vessel can cause skin lesions called petechiae

The organisms may destroy brain and heart tissue

-All rickettsial disease can cause fever, headache, weakness and liver and spleen enlargement

-Infection can be treated with antibiotics but it often remains latent

-Organisms are transmitted to humans through arthropod vectors

Typhus Fever (systemic diseases)

-Caused by Rickettsia Prowazekii and is transmitted from bites of the body lice which releases the organism

-Scratching bite area causes the organism to enter the skin

-Organism can spread easily in overcrowded and unclean environments

-A vaccine is avaliable

-A recurrence of this infection is called Brill-Zinsser disease which caused milder symptoms

Rocky Mountain Spotted Fever (systemic diseases)

-Caused by rickettsia, which is transmitted by ticks

-Antibiotics are used to treat the infection but can be lethal in untreated

Meningitis (nervous system diseases)

-Neisseria meningitidis is often the cause and there are 6 strains that cause this infection

-Organism makes a capsule and an unusual large amount of endotoxin which can cause an infected person to go into shock

-Symptoms start rapidly, treatment must begin to prevent death

-Vaccines available to the common strains in the USA (B,C,Y)

-People can be carriers of the organism and not become sick themselves

-Haemophilus influenzae type B (Hib) was the common cause of bacterial meningitis in young children before the Hib vaccine became available

-Haemophilus influenzae is the common cause of pneumonia

Listeriosis (nervous system diseases)

-Contaminates many food, especially dairy products

-Listeria monocytogenes is the organism that causes the disease and can survive in macrophages

-Problem for immunocompromised people and can cross the placenta and cause death of the fetus

Tetanus (nervous system diseases)

-Clostridium tetani is an anaerobic, endospore former

-Spores can infect a puncture wound and the spores germinate into vegetative cells and release an exotoxin

-Exotoxin can get into bloodstream and causes muscles to stay in a permanent state of contraction with ultimate death

-Lockjaw is common term associated with this disease

-Vaccine for tetanus, which is the toxoid

Botulism (nervous system diseases)

-Caused by Clostridium botulinum

-Makes the most potent toxin know which is a neurotoxin carried on a prophage

-This neurotoxin prevents muscles in the body from contracting and they stay in relaxed state (flaccid paralysis)

-Illness can be food born if the toxin is contaminating food (food poisoning)

-Canned food not treated properly can be the source since the organism is anaerobic and an endospore former

-Endospores can germinate in canned food since the environment is anaerobic

-If infants eat honey contaminated with endospores, the endospores can germinate into toxin producing organisms and causes “floppy baby” syndrome

-Endospores can also contaminate a wound and germinate into vegetative cells producing the toxin