Lincomycin

Lincomycin KENNETH KAPLAN, M.D. LOUIS WEINSTEIN, Ph.D., M.D.

Lincomycin (Lincocin) is an antibiotic elaborated by an actinomycete, Streptomyces lincolnensis, var. lincolnensis, isolated from a soil specimen obtained from Lincoln, Nebraska. It was first recovered from fermentation broths by Mason and his colleagues in 1962.24 Paper chromatography indicated that it differed from all other antibiotics. Using solvent extraction methods, Herr and Bergy13 isolated and purified the drug and prepared a crystalline hydrochloride salt. In the same year, Handa and his co-workers l l devised a microbiological assay procedure sensitive to within 0.25 mg. per mI., and Lewis and his colleagues20 reported that the range of antibacterial activity of lincomycin in vitro and in vivo was comparable to that of erythromycin. CHEMICAL PROPERTIES

Lincomycin is a monobasic compound. The hydrochloride consists of white orthorhombic crystals and is very soluble in water, soluble in methanol and ethanol, and relatively insoluble in less polar organic solvents. The free base is soluble in water and also in most organic solvents other than hydrocarbons. 24 The molecular weight is 455. The antibiotic is composed of a 4-alkyl substituted hygric acid joined to an alkyl 6amino-a-thio octopyranoside by an amide bond. 14 Chemical modifications of the parent compound have been reported to alter the in vitro antibacterial activity of the drug against both gram-positive and gramnegative bacteria and to increase the rate of absorption from the intestinal tract. 22 None of these new derivatives have yet been extensively studied and none are commercially available. Therefore lincomycin, the only commercially available member of this group of drugs, is chemically distinct from all other available antimicrobial agents. From the Infectious Disease Service of the New England Medical Center Hospitals and the Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts

Pediatric Clinics of North America-Vol. 15, No.1, February, 1968

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MECHANISM OF ACTION

Studies of the utilization of HC lysine in the logarithmic phase of growth of Staphylococcus aureus have shown that about 92 per cent of the incorporation of the amino acid into the protein fraction of the organisms is inhibited by 50 p.g. per mI. of lincomycin. Interference with protein synthesis begins immediately upon exposure to the antibiotic. Incorporation of the labelled compound into the cell wall is not significantly affected, although the proportion of lysine in the walls of treated bacteria is increased,u Studies by Chang et al,3 have shown that lincomycin belongs to a group of antibiotics which inhibit the binding of sRNA to the ribosomemessenger complex. Drug-sensitive gram-positive bacteria have metabolic characteristics not shared by ribosomes from resistant gram-negative bacteria. The binding of 14C phenylalanine-sRNA to the ribosome of sensitive bacteria has been found to be inhibited by lincomycin. The 50 S ribosomal subunits of sensitive bacteria were found to be the site of action of this effect, and both 50 S subunits from Escherichia coli and 30 S subunits from sensitive and resistant bacteria were unaffected.

IN VITRO ACTIVITY

The primary activity of lincomycin is bacteriostatic; bactericidal levels range up to 30 times those required to produce bacteriostasis. Almost all of the strains of Staph. aureus isolated in the United States, Great Britain and Canada have been found to be inhibited by concentrations of 2 to 2.8 p.g. per mI. of the drug. 1. 3. 1,5. 18. 20 On the other hand, Daikos and his colleagues 4 noted that 15 per cent of staphylococci recovered from patients in Greece multiplied in the presence of 5 p.g. per mI. of lincomycin. Serial subculture of Staph. aureus in increasing quantities of the drug leads to a relatively slight increase in resistance after 20 to 30 transfers; an occasional strain becomes insensitive to a concentration of 100 p.g. per mI. or higher. 18 Some strains of staphylococci that are resistant to erythromycin are also not suppressed by lincomycin. 1 Diplococcus pneumoniae, group A ,B-hemolytic streptococci and the viridans group of streptococci are inhibited by 0.5 p.g. per mI. or less of lincomycin. Corynebacterium diphtheriae and Bacillus anthracis are sensitive to a concentration of 2 p.g. per mI.12 Enterococci are poorly susceptible to the antibiotic; a few strains are sensitive to less than 10 p.g. per mI., but most are not suppressed by quantities as large as 100 p.g. per mI.l. 18. 20 The meningococcus and gonococcus and some nonpathogenic neisseria (sicca, catarrhalis) are suppressed by lincomycin in a concentration of 30 p.g. per ml. 18 Strains of gonococci either highly sensitive or slightly sensitive to

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penicillin G were found to be inhibited by lincomycin only at average concentrations of 18.5 and 30.5 jLg. per mI. respectively.23 E. coli, indolepositive and indole-negative strains of Proteus, Alcaligenes faecalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Aerobacter aerogenes, Hemophilus influenzae, Pasteurella multocida, Shigella and Salmonella are resistant to concentrations of the antibiotic as high as 4000 /Lg. per mI.lS Most strains of Bacteroides, Fusobacterium and the anaerobic cocci are sensitive to lincomycin and are inhibited by drug concentrations of 5/Lg. or less. A few strains of Actinomyces, Veillon ella and Bifidobacterium have shown a similar high degree of antibiotic sensitivity. 5 Antagonism between lincomycin and erythromycin has been shown both on solid and liquid culture media at concentrations of drug that can be achieved in the serum. This appears not to be the result of a chemical reaction between the two drugs; altered metabolism of the staphylococci apparently induced by erythromycin is thought to lead to inhibition of the action of lincomycin on the bacterial cell. lo EXPERIMENTAL IN VIVO ACTIVITY The development of experimental chronic pyelonephritis due to a variety of bacteria can be prevented in 50 per cent of animals by treatment with lincomycin. When the drug is given subcutaneously, the dose required for different organisms is as follows: Strep. pyogenes, 0.7 mg. per kg.; Staph. aureus, 6.5 mg. per kg.; D. pneumoniae, 18 mg. per kg.; Strep. viridans, 29 mg. per kg. From two to six times more antibiotic is needed to produce the same effects when it is given by mouth. These doses are comparable to the median protective quantities of erythromycin required for the same types of infection. Experimental disease in mice due to Staph. aureus resistant to erythromycin and other antimicrobial agents responds well to lincomycin. Staphylococci injected serially into rabbits treated with erythromycin or lincomycin do not become drug-resistant. The antibiotic protects 50 per cent of animals against experimental infection with Leptospira pomona. It is ineffective in artificially induced gram-negative bacterial disease. 2o

ABSORPTION, DISTRIBUTION, AND EXCRETION

About 20 to 35 per cent of an oral dose of lincomycin is absorbed from the gastrointestinal tract in the fasting state. The administration of 0.5 gm. by this route produces average peak plasma values of from 2 to 5/Lg. per mI.; maximal levels after 1 gm. are about 50 per cent higher. Antibiotic activity is detectable in the blood 1 hour after treatment, reaches its height at 2 to 8 hours, and is still present 12 and sometimes 24 hours later. Oral administration closely following meals reduces the peak serum levels by about 50 per centIs Intramuscular injection of 600 mg. of lincomycin in adults produces peak plasma concentrations of about 8 to 12 /Lg. per mI. at 1 to 2 hours; these gradually decline over 24 hours to values of 1 /Lg. per mI. or less.

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The intravenous infusion of 300 mg. of the antibiotic every 12 hours yields maximal blood levels of 9 to 11 p.g. per ml., which fall to 2 p.g. per ml. after 12 hours; a dose of 600 mg. given in the same manner produces peak plasma concentrations of 15 to 20 p.g. per ml. and low values of 6 p.g. per ml,29 Very few studies of the absorption and excretion of lincomycin have been carried out in children. Investigations in our laboratory indicate that the intramuscular injection of 75 to 100 mg. per kg. per day in three or four equally divided and spaced doses produces sustained plasma concentrations in excess of 8 p.g. per ml. Single oral doses of lincomycin of 22 to 33 mg. per kg. to children have been shown to produce peak values of 4 to 9 p.g. per ml. 4 hours after administration. Maximum values of 5 to 6 p.g. per ml. were found after oral doses of 33 to 44 mg. per kg. per day during several successive days of treatment of children 3 to 16 years of age. 27 Lincomycin is diluted in the body through a volume approaching the total weight. It is not confined to the extracellular space and is distributed in all tissues,2l The drug penetrates the blood-brain barrier to a small degree in patients with normal meninges. In the presence of meningitis, cerebrospinal fluid concentrations may be 40 per cent of plasma levels. 18 The antibiotic crosses the placenta and is present in the milk of rats. 8 Lincomycin is detectable in significant concentrations in the spleen, testes, heart, liver, kidneys and lung of treated animals; only minimal quantities are present in brain. Levels of antimicrobial activity in most of these organs remain constant for 2 hours after the intravenous injection of 25 mg. of lincomycin, and then decrease so that, after 4 hours, they are Y2 to Y2 0 of the maximal values.26 About 30 to 60 per cent of a single parenteral dose of lincomycin is excreted in the urine as microbiologically active drug in 24 hours. The manner of disposal of the remaining drug is presently unknown. Persons with renal disease have been noted to have elevated and prolonged blood levels of lincomycin. Adults with stable blood urea nitrogen values of 88 to 140 mg. per 100 ml. and who are given 600 mg. of intramuscular lincomycin develop mean serum levels of 24.4 p.g. per ml. at 1 hour, 10.5 p.g. per ml. at 12 hours and 4.4 p.g. per ml. 24 hours after drug administration. These values are approximately two to three times normal. Patients with severe renal disease and blood urea nitrogen levels of over 100 mg. per 100 ml. have been noted to have even higher serum concentrations of the drug, which were not reduced significantly by either peritoneal dialysis or hemodialysis. Peak concentrations, calculated drug half-life, and pharmacologic time concentrations (area under the curve) were three to seven times the values in normal subjects. It is not known whether this is the result of impaired excretion or of alterations in antibiotic distribution. These observations indicate that the dose of drug should be reduced by 60 to 80 per cent in the presence of severe renal disease. 28

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UNTOWARD EFFECTS IN ANIMALS Studies of the toxicity of lincomycin in animals have revealed that some mice, rats, rabbits, monkeys and cats exhibit a high degree of tolerance to the drug, while the guinea pig is very susceptible. Subcutaneous administration of 75 mg. per kg. per day or two daily doses of 300 mg. per kg. for 5 to 14 days produces death in practically all guinea pigs. Among the manifestations exhibited by the animals are anorexia, diarrhea and convulsions. Leukopenia and the presence of immature granulocytes in the peripheral blood are other features of toxicity of the drug in this species. Examination of the tissues reveals abscesses in the wall of the gallbladder in most instances and collections of purulent exudate in the intestine, cecum and spleen in some instances. 29 The precise cause of death has not been established, but it appears to be overgrowth of resistant coliform bacteria in the intestinal tract with invasion of the wall and, in some animals, secondary septic foci due to these organisms. The hamstring muscles of dogs given repeated intramuscular doses of lincomycin show mild diffuse hemorrhage, edema, altered connective tissue and proliferation of fibroblasts along the sciatic nerve below the area of injection. Rabbits exhibit little injury at sites of injection of doses of 50 mg. of lincomycin in 1 ml. of water; 300 mg. in 1 ml. of diluent causes muscle degeneration and hemorrhage; the same changes occur when 50 mg. of erythromycin dissolved in 1 mI. of water is injected. 29 Neither intra-articular nor intrathecal administration of the drug to animals appears to cause significant local inflammation. When lincomycin is administered during gestation, no teratogenicity has been observed in rats. 9

TOXICITY IN MAN

Lincomycin produces few untoward effects in man. Cross-sensitization reactions do not occur in patients allergic to penicillin. Diarrhea develops in about 20 to 50 per cent of those treated via the oral route;12. 15 this usually is mild and easily controlled. In some patients, however, especially those who have continued the drug once this has started, or in those who have taken large oral doses, diarrhea may be severe and persist for weeks after the drug is stopped. A clinical picture simulating acute ulcerative colitis may appear, with fever, severe abdominal cramps, intestInal distention, leukocytosis and blood, pus and mucus in the stool. Sigmoidoscopy reveals hyperemic and friable colonic mucus with no ulcerations or polyps, and roentgenologic examination of the colon shows no organic lesions. Symptoms subside after treatment with a low-residue diet and opiates. A single instance of granulopenia occurring during therapy was ascribed to a simultaneous viral infection. 2 Vague generalized aches and pruritus have been noted in some treated patients. Intramuscular injections are virtually painless. Rapid intravenous infusion (600 mg. in 5 to 10 minutes) may cause Hushing and a sensation of warmth which persists for about 10 minutes. The incidence of superinfection associated with the use of the drug appears to be low because of its narrow spectrum. Although no other untoward effects associated with the use of lincomycin have been reported, it must be emphasized that this agent has

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been used for too short a period to allow an adequate appraisal of its potentialities to produce reactions.

ROUTES OF ADMINISTRATION AND DOSAGE

Lincomycin is available in capsules containing 250 and 500 mg. of the drug and as a pediatric syrup with 250 mg. in 5 ml. for oral use. Ampoules, in which 300 mg. or 600 mg. of the hydrochloride salt are dissolved in 10 ml. or 20 ml. of benzyl alcohol, are available for parenteral administration. The oral dose of lincomycin for adults is 0.5 to 1 gm. three or four times daily; the drug should be given no earlier than 2 hours after and no later than half an hour before a meal. The dose for children is 50 to 100 mg. per kg. per day divided into three or four equal injections. When administered intravenously, lincomycin should be dissolved in about 50 ml. of 5 per cent dextrose in water or in saline and infused over a 30minute period.

THERAPEUTIC USE

The clinical effectiveness of lincomycin is difficult to evaluate for several reasons. A number of the variable reports do not include microbiological data sufficiently adequate for interpretation of the activity of the drug against specific etiological agents. Information concerning plasma levels that would allow assessment of the antimicrobial effects of the antibiotic is lacking in some instances. In addition, in some types of disease, the number of cases treated is too small and clinical experience too short to permit any final conclusions concerning the therapeutic usefulness of lincomycin. A number of human infections have been treated successfully with lincomycin. Among these are osteomyelitis, septic arthritis, pneumonia, meningitis, subacute bacterial endocarditis, erysipelas, cellulitis, group A Strep. pyogenes pharyngitis and the acute and carrier states of diphtheria. 1 , 7, 16, 18,30 Infections, both in children and adults, caused by Strep. mitis, Strep. pyogenes, Staph. aureus and D. pneumoniae respond well to therapy with this agent. Human infections produced by gram-negative bacteria including neisseria are unaffected by the drug. Lincomycin has been shown to be approximately as effective as penicillin in curing susceptible infections. Similar comparative studies with erythromycin are not available. It appears that lincomycin, like erythromycin, can be considered an acceptable substitute for penicillin in penicillin-sensitive patients, and it may be substituted for the penicillinase-resistant penicillins for infections caused by most resistant strains

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of Staph. aureus. The fact that lincomycin possesses a rather narrow range of antimicrobial activity necessitates precise identification of the causative agent of an infection and determination of its susceptibility to the drug. Lincomycin appears to be espe~ially effective for the treatment of chronic staphylococcal osteomyelitis, even when given orally in a dose of 2 gm. per day.25 Whether this is related to a particular affinity of the drug for bone or to enhanced antimicrobial activity in osseous structures is unknown. Holloway and his colleagues15 found a concentration of 1 to 2.2 p.g. of lincomycin per gram of bone with concomitant plasma levels of 6 to 16.5 p.g. per ml.; on one occasion, 6.6 p.g. of the antibiotic per gram of bone was noted, but no coincident blood level was reported. Grady and Stern6 have reported that rats given lincomycin orally in single doses of lOO mg. per kg. rapidly achieve peak concentrations of drug of 3.7 to 9.9 p.g. per gram of wet bone. Concentrations in bone were higher, were achieved more rapidly and persisted longer at levels higher than those in the blood, so that 8 hours after the drug was given bone values of 1.7 to 4.1 p.g. per ml. were four to seven times greater than those in the circulation. Although they used similar techniques, Kessler and co-workers19 had contradictory results, with bone levels one third those of serum, a similar half-life in bone and serum, and no evidence of drug accumulation in bone.

SUMMARY

Lincomycin is an antibiotic with a structural configuration different from that of all of the commonly used antimicrobial agents. It inhibits bacterial growth by intedering with protein synthesis. The antimicrobial spectrum of the drug is relatively narrow; its range of activity resembles that of erythromycin and it is effective against Staph. aureus, Strep. viridans, Strep. pyogenes, D. pneumoniae, C. diphtheriae, fusospirochetes, Bacteroides, anaerobic streptococci and B. anthracis in a concentration of 2 to 5 p.g. per mI. or less. Twenty to 35 per cent of orally administered linocomycin is absorbed from the gastrointestinal tract. Doses of 0.5 to 1 gm. by mouth produce average peak plasma levels of 2 to 5 p.g. per ml. for 2 to 8 hours; detectable antibacterial activity persists for at least 24 hours. Single intramuscular injections of 600 mg. yield blood levels of 8 to 11 p.g. per mI.; intravenous infusions given every 12 hours produce concentrations of 20 p.g. per ml. in the circulation. Lincomycin penetrates the normal bloodbrain barrier poorly but is present in significant quantities in the cerebrospinal fluid when the meninges are inflamed. About 50 per cent of a dose is excreted in the active form in the urine. In the presence of renal disease, the drug achieves higher levels that persist for longer periods of

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time. Neither hemodialysis nor peritoneal dialysis appears to be effective in reducing these levels significantly. Diarrhea is the major toxic manifestation in man and occurs in 20 to 50 per cent of treated patients. If the drug is continued after this complication has developed, diarrhea may become severe and persist for weeks after therapy is stopped. Although inflammatory reactions occur about sites of injection of the drug in muscle, they are less marked than those produced by erythromycin. Lincomycin appears to be therapeutically effective in pneumonia, suppurative arthritis, meningitis, endocarditis, cellulitis, tonsiIlopharyngitis, erysipelas, abscesses and chronic osteomyelitis when these disorders are due to Staph. aureus, Strep. pyogenes, anaerobic streptococci, Strep. viridans and D. pneumoniae. It appears to have special usefulness as an alternative drug in the treatment of these diseases in penicillin-sensitive individuals. Acute diphtheria and the carrier state are probably also benefited by the drug. Lincomycin may have special usefulness in chronic staphylococcal osteomyelitis. Infections due to gram-negative bacteria are unaffected. The conventional daily doses of the antibiotic are 2 to 4 gm. for adults and 75 to 100 mg. per kg. for children; the required amount is divided into three or four equally sized and spaced doses. More study of and experience with lincomycin are necessary before its precise value in the chemotherapy of infection and its potential for producing untoward effects can be fully evaluated.

REFERENCES 1. Barber, M., and Waterworth, P. M.: Antibacterial activity of lincomycin and pristinamycin: A comparison with Erythromycin. Brit. Med. J., 2:603-606, 1964. 2. Brown, E. B., and Cunningham, L. E.: Granulopenia occurring during the administration of lincomycin. J.A.M.A., 194:668-670, 1965. 3. Chang, F. N., Sih, C. J., and Weisblum, B.: Lincomycin, an inhibitor of aminoacyl sRNA binding to ribosomes. Proc. Nat. Acad. Sc., 55:435-438, 1966. 4. Daikos, G. K., Kontomichalon, P., Papadoyannakis, N., and Tourkantonis, A.: Clinical and laboratory experience with lincomycin. Antimicrobial Agents and Chemotherapy 1963, pp. 197-199. 5. Finegold, S. M., Haraela, N. E., and Miller, L. G.: Lincomycin: Activity against anaerobes and effect on normal human fecal flora. Antibiotic Agents and Chemotherapy 1965, pp. 659-667. 6. Grady, J. E., and Stern, K. F.: Penetration of lincomycin into bone. Antibiotic Agents and Chemotherapy 1965, pp. 201-205. 7. Grandin, C., St. Martin, M., and Potuin, A.: Lincomycin and staphylococcal infection. Canad. Med. Assoc. J., 92:1062-1065, 1965. 8. Gray, J. E., Purmalos, A., and Fienstra, E. S.: Animal toxicity studies of a new antibiotic, lincomycin. Toxicology and Applied Pharmacol., 6:476-494, 1964. 9. Gray, J. E., Purmalis, A., and Mulvihill, W. J.: Further toxicologic studies of lincomycin. Toxicology and Applied Pharmacol., 9:445-454, 1966. 10. Griffith, L. J., Ostrander, W. E., Mullins, C. G., and Besurck, D. E.: Drug antagonism between lincomycin and erythromycin. Science, 147:740-747, 1965. 11. Hanka, L. J., Mason, D. J., Burch, M. R., and Treick, R. W.: Lincomycin, a new

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antibiotic. III. Microbiological assay. Antimicrobial Agents and Chemotherapy 1962, pp. 565-569. Harnecker, J., Contneras, J., Gilafert, B., and Ubilla, V.: Bacteriological and clinical studies of lincomycin hydrochloride. Antimicrobial Agents and Chemotherapy 1963, pp. 204-209. Herr, R. R., and Bergy, M. E.: Lincomycin, a new antibiotic. II. Isolation and characterization. Antimicrobial Agents and Chemotherapy 1962, pp. 560-564. Hoeksema, H., Bannister, B., Birkenmeyer, R. D., et al.: Chemical studies on lincomycin I. The structure of lincomycin. J. Am. Chem. Soc., 86:4223-4224, 1964 Holloway, W. J., Kahlbaugh, R. A., and Scott, E. G.: Lincomycin, a clinical study. Antimicrobial Agents and Chemotherapy 1963, pp. 200-203. Jackson, H., Corpa, J., Mellinger, W. J., and Olsen, A. R.: Group A fl-hemolytic streptococcal pharyngitis-Results of treatment with lincomycin, J.A.M.A., 194: 1189-1192, 1965. Josten, J. J., and Allen, P. M.: The mode of action of lincomycin. Biochemical and Biophysical Research Assoc., 14:241-244, 1964. Kaplan, K., Chew, W. H., and Weinstein, L.: Microbiological, phamacological and clinical studies of lincomycin. Amer. J. Med. Sc., 250:137-146, 1965. Kessler, H. J., Naumann, P., and Kempf, J.: Lincomycin: Serum and bone levels in the rat. Brit. J. Pharmacology and Chemotherapy, 30:627-630, 1967. Lewis, C., Clapp, H. W., and Grady, J. E.: In vitro and in vivo evaluation of lincomycin, a new antibiotic. Antimicrobial Agents and Chemotherapy 1962, pp. 570-582. Ma, P., Lim, M., and Noden, J. H.: Human pharmacological studies of lincomycin, a new antibiotic for gram positive organisms. Antimicrobial Agents and Chemotherapy 1963, pp. 183-188. Magerlein, B. J., Birkenmeyer, R. D., and Kagan, F.: Chemical modification of lincomycin. Antibiotic Agents and Chemotherapy 1966, pp. 727-736. Martin, J. E., Samuels, S. B., Peacock, W. L., Jr., and Thayer, J. D.: Neisseria gonorrhoeae and Neisseria meningotides sensitivity to spectinomycin, lincomycin and penicillin G. Antibiotic Agents and Chemotherapy 1965, pp. 437-439. Mason, D. J., Dietz, A., and Deboer, C.: Lincomycin, a new antibiotic. I. Discovery and biologic properties. Antimicrobial Agents and Chemotherapy 1962, pp. 555-559. McMillan, N. L., McRae, R. K., and McDougall, A.: Lincomycin in the treatment of osteomyelitis. Practitioner, 198:390-395, 1967. Meyer, C. E., and Lewis, C.: Absorption and fate of lincomycin in the rat. Antimicrobial Agents and Chemotherapy 1963, pp. 169-175. Nunnery, A. W., and Riley, H. D.: Clinical and laboratory studies of lincomycin in children. Antimicrobial Agents and Chemotherapy 1964, pp. 142-146. Reinarz, J. A., and McIntosh, D. A.: Lincomycin excretion in patients with normal renal function, severe azotemia and with hemodialysis and peritoneal dialysis. Antimicrobial Agents and Chemotherapy 1965, pp. 232-238. Wagner, J. G., and Alway, C. D.: Prediction of multiple dose serum levels of "Lincocin" from single dose serum levels when "Lincocin" (as the hydrochloride) was administered by constant rate intravenous infusion. Nature, 201:1101-1103, 1964. Walters, E. W., Romansky, M. J., and Johnson, A. C.: Lincomycin, laboratory and clinical studies. Antimicrobial Agents and Chemotherapy 1963, pp. 210-215.

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