a. General.

It is difficult to identify microorganisms under a microscope unless
they have been stained.

Hans Christian Gram, a Danish histologist, developed the Gram stain procedure in 1884, a procedure used universally. Bacteria are classified as either positive or negative, depending on their stain reaction.

An organism that takes up and retains the crystal violet stain will appear purplish under the microscope; these are gram-positive organisms. Other organisms will retain the pink or red counterstain, safranin. These organisms are known as gram-negative.

b. Staphylococcal Infections.

(1) Signs/symptoms. The basic symptoms of swelling, pain, redness, and heat at the infection site are present. There may be abscess formation at the site also. Initially, the abscess will be firm; then it becomes yielding when touched, indicating that the center is full of liquid (pus). The abscess will often drain spontaneously and thick
yellow or cream colored pus will come out. Lymphadenitis (inflammation of the lymph glands) and lymphangitis (inflammation of the lymphatic vessels) are both common manifestations of staphylococcal infections.

(2) Treatment. Have the patient rest and elevate the affected area. Apply moist, warm compresses to promote the healing process. In a relatively small, recent wound, this treatment will usually be sufficient. If the wound is large and purulent, complete these first two steps, then make an incision and drain the wound. Squeeze
out any exudate in the wound. Irrigate the wound with normal saline solution and/or antiseptic solution such as povidone-iodine. Clean the wound thoroughly, being sure all foreign matter and exudate has been removed.

Dress the wound with sterile gauze packing. Use iodoform gauze to stuff down in the wound with just the tip (the wick) sticking up. This gauze will soak up the exudate which will be made as part of the healing process. The wick is to allow the person changing the dressing to remove the soiled gauze easily. Put a nonadherent cover over the wicking. (Telfa is a plastic-like coating on one side of a gauze dressing that prevents the dressing from adhering to the wound.) Be sure the dressing is changed daily.

c. Streptococcal Infections.

(1) Signs/symptoms. As with staphylococcal infections, the basic symptoms are swelling, pain, redness, and heat at the infection site. Generally, there is no abscess formation, but there is a rapid spread of infection from the edge of the wound outward through the skin and subcutaneous tissue.

(2) Treatment. Advise the patient to rest and elevate the affected area. Apply moist, warm compresses to promote the healing process. Always administer antibiotic therapy as directed by a physician.

d. Gas Gangrene (Clostridium Bifermentans or Clostridium Perfringens, Class A and F.)

Gas gangrene is an infection that comes on suddenly and violently in
dead tissue and spreads rapidly. The infection is caused by one of several clostridia–Clostridium perfringens, Clostridium novyi, or Clostridium speticum, for example.

Moving into dead or dying tissues, these organisms use amino acids and carbohydrates from the cells. Gas is produced that stretches tissues and interferes with blood supply and oxygenation. The organisms multiply and secrete enzymes that destroy living
tissues adjacent to the wound as well as red blood cells. In this way, infection continues to spread. As the organisms continue to multiply, infection accelerates and advances, making severe anemia and toxemia possible. Eventually, acute toxemia may result in shock and rapid death.

(1) Signs/symptoms. The infection begins suddenly with rapidly increasing pain in the affected area, a fall in blood pressure, and tachycardia. The patient becomes anxious and frightened with a slight fever (less than 101ºF) and profuse sweating. His pulse is elevated (greater than 120 beats per minute). The wound itself
becomes swollen and the skin around the wound is pale due to accumulation of fluid under the skin. The wound has a reddish-brown discharge that is a foul-smelling fluid.

As the infection progresses, the surrounding tissue changes from pale to dusky and finally becomes deeply discolored with red, fluid-filled sacs. When the skin surface is lightly touched, gas in the tissues may be felt. Eventually, the patient suffers severe prostration, stupor, delirium, and coma.

(2) Treatment. Treatment must begin immediately. Delay could mean loss of life. The most important treatment is surgical removal of any dead tissue in the involved area and airing of the wound. Keep the wound open to drain. Give penicillin intramuscularly every 3 hours and tetanus toxoid according to local standing operating
procedure. Hyperbaric oxygen therapy may be helpful. In hyperbaric oxygen therapy, the patient is placed in a hyperbaric chamber, a room which contains oxygen at a concentration and pressure much higher than the normal atmosphere. The patient’s bloodstream and tissues are saturated with oxygen for one to three hours at a time.
Repeat this treatment every six to eight hours. Manage shock and dehydration if present and evacuate the patient.

e. Tetanus.

Caused by the organism Clostridium tetani, tetanus attacks the
central nervous system. The organism is found in the soil and feces of animals and humans. The organism enters the body through a puncture wound or pus-filled, dead tissue. Tetanus is an acute, infectious disease caused by the toxin of tetanus bacillus.

(1) Signs/symptoms. The first symptoms may be pain and tingling at the wound site followed by spasms of the muscles located close to the wound. Usually, the first symptoms are jaw stiffness, neck stiffness, dysphagia (difficulty swallowing), and irritability.

Minor stimuli can cause painful, long lasting convulsions. During
convulsions, the glottis and respiratory muscles may go into spasm so that the patient cannot breathe and he may die from lack of oxygen. Throughout the illness, the patient has only a low grade fever. Contraction of facial muscles may cause the patient’s face
to have a mask-like grin (risus sardonicus).

(2) Prophylaxis at time of injury (precautions taken to prevent the disease). A person who gets a wound and suspects that Clostridium tetani organism might be present should receive tetanus toxoid immediately. Administer 0.5 cc intramuscularly in a dosage of 25 to 500 units. The dosage depends on the seriousness of the wound, not
on the age or weight of the patient. Patients who have had tetanus immunizations should be given a tetanus toxoid booster of 0.5 cc intramuscularly immediately. An exception can be made if the patient has had a tetanus toxoid booster in the last five
years. In the case of a severe, puncture wound, if the patient has had a tetanus toxoid booster in the past twelve months, another tetanus booster need not be given.

(3) Treatment. Give 5000 units of tetanus immune globulin (human)
intramuscularly. Give tetanus antitoxin, 100,000 units intravenously after testing for horse serum sensitivity if tetanus immune globulin is not available. Put the patient on bed rest and avoid exciting him. Take steps to maintain the airway. Administer penicillin-G or tetracycline as directed. Clean the wound thoroughly of dead tissue and foreign matter. If necessary, feed the patient by gastric tube. Insert a Foley catheter if urinary retention occurs.