Uses of Penicillin

Penicillin is now the drug of choice in the treatment of many types of bacterial infection. It is not a cure-all, however, and it is of little or no value in the treatment of many serious diseases. Generally speaking, its application can be correlated with the identity and character of the pathogen. It is particularly effective against the pyogenic cocci and the gram-positive, spore-forming bacilli, including the anaerobic forms belonging to the genus Clostridium.

Penicillin may be administered in a variety of ways, including intramuscular, intravenous, or local injection; by continuous intravenous drip; and by topical application. The intramuscular method is most commonly used. A solution of penicillin of appropriate concentration is made with sterile isotonic saline, or distilled water. The dosage commonly ranges from 10,000 to 30,000 units and is administered every 3 hours, day and night. It is important that the injections be continued until the clinical picture clearly warrants their cessation.

The intravenous method is usually employed for the purpose of obtaining quickly a blood concentration of penicillin adequate to halt or reduce infection. Penicillin may be injected locally into abscesses, joint cavities, and so forth in varying doses, depending upon the extent of the infection. Penicillin may also be administered topically at localized sites of infection, where it is applied in the form of wet compresses or as a powder. As penicillin becomes more generally available it is probable that it will be administered orally on an increasingly greater scale. To obtain the proper blood levels to combat and eliminate infection, it is necessary to give four to five times the amount required if administered parenterally. The patient's gain in comfort would more than compensate for the added cost of the drug.

The total amount of penicillin necessary to clear up an infection depends upon the nature and extent of the infection and the sensitivity of the causative organism. The gonococci are the most sensitive of all pathogens and most cases of gonorrhea can be cured by a series of 3 to 6 intramuscular injections of 30,000 units administered at 3-hour intervals. Cases of bacterial endocarditis, on the other hand, require much greater amounts of penicillin, often running to several million units administered at rates of 200 thousand to 1 million units a day. While specific hospital cases require varying amounts of the drug, an average figure would be approximately a million units administered over a period of 3 to 7 days.

Penicillin is usually marketed in the form of the sodium salt and the methods of administration cited above are based upon the use of solutions of the drug in this form. It may also be embodied in the form of ointments or creams that find their greatest usefulness for the treatment of second- or third-degree burns and localized surface infections. It may be suspended in a suitable vehicle for nebulization and used as a nasal or oral spray to combat infection of the throat and nasal passages. The use of penicillin in the form of troches and dental cones has been recommended to combat oral infections.

Penicillin has played a major role in military medicine. It was employed quite freely in forward areas as a preventative measure to forestall the development of gas gangrene and other serious infections. Behind the lines, it found wide application in the treatment of osteomyelitis and other deep-seated wound infections in addition to the multiple uses for which it is recommended in general practice. New uses for penicillin are constantly being discovered, new modes of administration are being developed, and clinical practice, therefore, is undergoing continual change.

In the field of veterinary medicine, the most successful application of Penicillin has been made in the treatment of bovine mastitis in which the causative organisms were Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus uberis. Streptococcic infections responded to smaller doses than those in which the invading organism was Staphylococcus aureus. The penicillin solution is administered through the teat canal immediately after a milking period and apparently has no adverse effects on the mammary glands or on the Quality of the milk.

Penicillin has been used with positive results in the treatment of strangles of horses caused by Streptococcus equi, in hemorrhagic septicemia of cattle, "shipping fever" of horses, swine erysipelas, peritonitis and osteomyelitis in dogs, and canine distemper. The method of administration and the dosage varies with the size of the animal, the nature and severity of the infection, and the identity of the causative organisms.

Additional pathogens causing diseases in animals that are known to be penicillin-sensitive include: Actinomyces bovis, causing actinomycosis of cattle; Bacillus anthraces, causing anthrax in cattle, sheep, and horses; Clostridium chauvoei, causing blackleg in cattle and sheep; Corynebacterium renale, causing pyelonephritis in cattle; C. equi, causing suppurative pneumonia in foals; Erysipelothrix rhusiopathiae, causing erysipelas in swine; Leptospira canicola, causing leptospirosis in hogs, dogs, cats, and foxes; Listerella monocytogenes, causing encephalitis in sheep, cattle, and swine; Streptococcus gallinarum, causing septicemia in chickens; and others.

Some investigations have indicated the possible usefulness of penicillin to combat certain plant diseases. Such studies have been limited in number and would need to be performed on a much more extensive scale before any conclusions can be reached regarding the usefulness of the drug in this field.

The addition of penicillin to milk and other highly perishable food products has been recommended but its usefulness as a food preservative is questioned. Penicillin in low concentrations will inhibit the growth of many bacteria responsible for food spoilage. It is not effective, however, in preventing the growth of other forms often equally responsible. Gram-negative species are usually not affected, and among the gram-positive forms, which are generally penicillin sensitive, a number of spore formers, such as Bacillus cereus, produce enzymes, termed pencillinases, which rapidly destroy the drug. While the addition of penicillin may extend somewhat the useful life of a product under certain conditions, the varied microflora, normally present precludes its continuing effectiveness.

THE AUTHOR

Kenneth B. Raper is senior microbiologist in charge of the Culture Collection Section, Fermentation Division, Northern Regional Research Laboratory, Peoria, Ill. He has been associated with the Bureau of Agricultural and Industrial Chemistry during most of the past 18 years. Dr. Raper holds degrees from the University of North Carolina, George Washington University, and Harvard University. At the Northern Regional Research Laboratory, Dr. Raper and his co-workers are building a large collection of cultures of fungi, yeasts, and bacteria, many of which are essential in the industrial fermentation processes used in the production of antibiotics and use full organic chemicals. During the period in which penicillin fermentation was being developed, he examined hundreds of cultures obtained from all parts of the world in efforts to discover strains of the Penicillium notatumchrysogenum group that would be more satisfactory than existing strains for the production of high yields of penicillin.