The Staphylococcus species and Staphylococcal Wound Infections
The Staphylococcus species, notably Staphylococcus aureus and Staphylococcus epidermis, are what cause staphylococcal wound infections, sometimes referred to as "staph" infections. These two harmful agents are resilient, thrive in the dry, salty environment found on human skin, and are therefore easily contagious from one person to the next. Toxic shock syndrome, septic arthritis, and abscess formation are the three primary signs of staphylococcal wound infections. S. aureus produces "many virulence factors" that are essential to the development of the disease and is the cause of more serious wound infections. For instance, clumping factor and other proteins such as lipases and proteases allow the attachment of cells to clots and tissues, causing tissue damage. Immunity to this agent is rare weak the species can attack and evade an organism’s immune defense. Bacteria develops and spreads in the wound leading to systematic complications such as abscesses in the heart and bones.
Risk Factors and Treatment of Staph Infections
The S. aureus mainly affects surgical wound individuals and this condition also affects people who suffer from a weak immune system or have used medical equipment that has gone directly inside their body. Advanced age, poor health, immunosuppression, and severe trauma to the skin are factors that increase the risk of contracting Staphylococcal wound infections. The treatment of staph infections is problematic because the species are resistant to antibiotics and sulfa drugs, clindamycin, and tetracyclines are the most common treatment methods. Prevention involves the quick closure of surgical wounds, not sharing towels or washcloths, and the thorough cleaning of any wounds.
Group A Streptococcal "Flesh-Eating Disease"
Group A streptococcal "flesh-eating disease" is the second common bacterial infection of the wounds. It is caused by streptococcus pyogenes, which is "β-hemolytic, Gram-positive, chain-forming, aerotolerant, with Lancefield group A cell wall polysaccharide and a hyaluronic acid capsule." The infections caused by the S. pyogenes can progress rapidly, even leading to death, and the dangerous ones are referred to as "invasive" that is. Spreading to the tissues and organs causing meningitis, pneumonia, and faciitis. The signs and symptoms of the 'flesh-eating disease' include severe pain and swelling in the wound area, discoloration of the skin, fevers, shock, and confusion. Unless the individual receives quick treatment, death follows within a short time.
Bacterium and Pathologic Effects of S. Pyogenes
The S. Pyogenes bacterium produces the F proteins which serve the purpose of colonizing the wound. There is also the release of enzymes such as streptokinase's which destroy the subcutaneous fat tissue and fascia, causing damage to the muscle tissues. Streptococcal pyrogenic exotoxins are also produced, and they lead to shock by causing helper T cells to release cytokines. The effect is tissue death and breakdown, fluid accumulation, excessive swelling, and multiplication of the dead tissue. The cases of the 'flesh-eating' diseases are rare, and individuals at risk of developing this condition are those suffering from diabetes, cancer, alcoholism, AIDS. Also, persons who have undergone recent surgery, abortion, childbirth, and injected drug abuse are at a high risk. Treatment requires immediate surgery to reduce the pressure of swollen tissue and remove the dead tissue because the toxins spread rapidly. Amputation may be necessary to remove the source of the toxins, and it is important to note that there are no preventive measures for "the flesh-eating disease."
Tetanus: An Anaerobic Wound Infection
Tetanus is a fatal condition common in the underdeveloped world, and it is caused by Clostridium tetani, an "anaerobic, spore-forming, Gram-positive, rod-shaped bacterium." The causative agent has two features, a "spherical endospore that forms at the end of a wall" and growth that spreads over a solid media surface. The signs and symptoms are continuous, painful, and uncontrollable muscle spasms, mainly limited to one part of the body. They begin with the jaw muscles hence the name 'lock-jaw,' and other symptoms include restlessness, irritability, swallowing difficulties, and seizures. Greater contraction of the muscles results in breathing difficulties, abnormality in the heart rhythm, and in severe cases fractures, lung damage, and pneumonia.
Bacterium and Pathologic Effects of Clostridium tetani
The Clostridium tetani localize colonization to the wound, and its tetanospasmin causes its pathologic effects. The tetanospasmin A-B toxin where the B portion attaches itself to motor neuron receptors, and the A portion is taken up by endocytosis. The toxin is then released to the neuron body cells via the spinal cord, stimulating the cells and in the process inhibiting muscle contraction. The toxin through the spinal cord spreads to the opposite side of the wound and moves downward, and as their amount increases, the wound gets infected. An infected wound releases the tetanospasmin to the central nervous system inhibiting the neurological ability of the brain, and the jaw muscles are the first to develop the spasms.
Risk Factors and Treatment of Tetanus
Cases of tetanus occur in puncture wounds from stepping on sharp objects such as wounds, piercing the body, bites from animals, drug abuse through injections, and stings from insects. Tetanus is also common for newborn babies, a condition known as neonatal tetanus, and is fatal with symptoms appearing fourteen days after birth. Treatment of tetanus is by the injection of the infected person with the human TIG (tetanus immune globulin) vaccine. Muscle relaxers are also provided, antibacterial medication such as metronidazole is given, and the wounds are thoroughly cleaned. Prevention of tetanus is by vaccination with the tetanus toxoid, that is, tetanospasmin in the inactivated form.
Clostridial Myonecrosis: Gas Gangrene
Clostridial myonecrosis, also known as "gas gangrene," is the second disease due to anaerobic wound infections. The condition is common in wounds that have been neglected, and they have bone fragments or severe tissue damage. There are several species of the Clostridium species, but Clostridium perfringens is the most common cause of this disease. It is endospore-forming but does not produce spores in wounds. The signs and symptoms appear between one to five days after infections, and they include severe pain, swelling in the wound area, and leakage of a thin, bloody fluid from the wound. The wound's overlying skin becomes tightly stretched, black, and the shocking part is that the victim is fully alert, and he or she becomes delirious and goes into a coma.
Bacterium and Pathologic Effects of Clostridium perfringens
The development of gas gangrene comes about as a result of two factors: the presence of dirt and dead tissue in a wound and a delay before the treatment of the wound. Dead tissue provides the species with a nutrient source, and it releases α-toxin, an enzyme that destroys lecithin in cell membranes, causing cell lysis. The released toxins get into the infected area, kill leukocytes and tissue cells, and as they reproduce, hydrogen and carbon dioxide are released. The gasses accumulate in the infected tissue, causing a pressure rise, and without the intervention of quick surgery, the toxins get into the bloodstream, destroying red blood cells and body structures.
Risk Factors and Treatment of Clostridial Myonecrosis
Clostridium perfringens is common in soil and the intestinal tract of animals as well as in neglected trauma and some surgical wounds. Also, it can occur in self-induced abortions and miscarriages. Individuals at risk include those suffering from arteriosclerosis and diabetes because they restrict blood flow and oxygenation to the tissues. Treatment requires quick surgery to remove the infected tissues, and amputation may be necessary. Antibiotics such as a combination of penicillin and clindamycin are used to control bacterial growth and the production of toxins. Prevention is by thorough cleaning of wounds and removal of dead tissue, and the disease has no vaccine.
