376 know if any drugs being given to an adult male could adversely affect spermatogenesis, even temporarily, and drugs likely to do so ought not to be given to males of low fertility or to normal couples desiring a child. of Physiology and Pharmacology, R.N.T. Medical College, Udaipur, 313 001, India
Departments
AJAY MURDIA VISHNU MATHUR L. K. KOTHARI K. P. SINGH
CORYNEBACTERIUM SPP IN HUMAN DISEASE
SIR,-Dr Vale and Dr Scott’ described the incidence of Corynebacterium bovis in human disease. The National Collection of Type Cultures (N.C.T.C.) has long had an interest in isolates of Corynebacterium spp. involved in human disease.2-4 Organisms of this group, other than C. diphtheria, comprise about 20% of the miscellaneous bacteria
sent to the N.C.T.C. for identification each year. 172 strains of coryneforms were received for identification in the period 1965-75, of which 35% were identified to species level, 43% to genus or possible species, and 22% were unidentified. Identification was attempted using methods and tables given in Cowanand information derived from Bergey’s Manualb and specialist papers, as well as the records of the N.C.T.C. on the cultures that it maintains. The low identification-rate is, in part, due to the poor classification of this group of microorganismse.g., various authors seem to have described different bacteria under the name C. bovis. A total of 15 strains of C. bovis or C. bovis-like organisms have been submitted to the N.C.T.C. for identification since 1965, including those described by Vale and Scott. Other Corynebacterium spp. received include: 2 C. aquaticum, 8 C. haemolyticum, 1 C. hofmannii, 1 C. minutissimum, 1 C. ovis, 6 C. pyogenes, 2 C. renale, 2 C. ulcerans, 29 strains which were very similar to one or other of these species, and 18 strains very similar to C. belfanti (10 strains), C. equi (2 strains), and C. xerosis (6 strains). In addition, 5 strains were identified as Brevibacterium spp. 50 strains could not be identified with named taxa, but 38 of these could be grouped into 6 "new" taxa.4 These bacteria were isolated from a wide variety of human specimens (blood cultures, 40 strains; urogenital tract, 7; pus, 10; cerebrospinal fluid, 7; ear, nose, and throat, 12; limbs, 16). The available details of the clinical conditions concerned were often scanty and no correlation was found between any particular syndrome and any one species or taxon, nor could the possible pathogenic effect of the isolates be evaluated in many of the cases. The genus Brevibacterium has rarely been implicated in human disease and Pitcherhas suggested that many skin bacteria may be more correctly placed in Brevibacterium than in Corynebacterium. Pitcher’s work and that of Hill et al.4 emphasise the difficulty of identifying many strains of coryneform-like bacteria of human origin. These results, together with those of Vale and Scott, suggest that coryneform-like bacteria do cause human disease and should not be ignored if isolated. J. E. HINE National Collection of Type Cultures, L. R. HILL Central Public Health Laboratory, London NW9 5HT S. P. LAPAGE
1. Vale, J. A., Scott, G. W. Lancet, 1977, ii, 682. 2. Bowie, I. S., Hill, L. R., Lapage, S. P. Second International Symposium on Rapid Methods and Automation in Microbiology, Cambridge, September 19-25, 1976; p. 91. Oxford 1977. 3. Hine, J. E., Hill, L. R., Lapage, S. P. ibid. p. 104. 4. Hill, L. R., Lapage, S. P. and the late Bowie, I. S. in Coryneform Bacteria (edited by I. J. Boufield and A. G. Callely); p. 181. London, 1978. 5. Cowan, S. T. Cowan and Steel’s Manual for the Identification of Medical Bacteria. Cambridge, 1974. 6. Buchanan, R. E., Gibbons, N. E. Bergey’s Manual of Determinative Bacteriology. Baltimore, 1974. 7. Pitcher, D. G. Br. J. Dermat. 1978, 98, 363.
PROTEIN BINDING AND ANTIBIOTIC CONCENTRATIONS
SIR,-Dr Gillett and Dr Wise1 claim to have demonstrated that protein binding of drugs has no effect on the concentration measured in a tissue space and that "the penetration of antibiotic into tissue fluid does not depend on the fraction of free drug in the blood". The technique Gillett and Wise used to abrade the skin and cause no "significant bleeding" means that the discs will contain a high protein filtrate of serum, or serum itself. Verwey and Williams have demonstrated rapid equilibrium between free plasma drug levels and peripheral lymph, indicating rapid free drug diffusion.2 We have found that serum proteins can bind large amounts of antibiotic.34Therefore, it is highly likely that the protein in Gillett and Wise’s discs, being mainly albumin, also significantly bound the antibiotics tested. They found tissue-fluid levels similar to serum levels because they were, in effect, measuring serum in their tissue-fluid model. We have demonstrated that the free drug level in serum is important and that the total concentration of a drug in a tissue fluid can be predicted from the serum concentration, the antibiotic serum protein binding, and the antibiotic protein binding in the tissue fluid being evaluated. The following formula has been highly predictive under equilibrium conditions in animal models: 5-7
[C.] . F, [Cc ]=tissue fluid drug concentration
=serum drug concentration
F.=free fraction of drug in serum Fe =free fraction of drug in tissue fluid. If protein binding in serùm and tissue fluid is identical then .F. =R and the tissue-fluid drug concentration will equal the serum concentration (exactly as demonstrated by Gillett and Wise). Our latest study has shown this to be true for both high and low protein containing extravascular fluid.7 Therefore, while we agree that high serum-protein binding of antibiotics is not necessarily a detriment, we believe that the concepts presented by Gillett and Wise are incorrect and that they further obscure the already confusing issue of antibioticprotein interactions. Infectious Disease Section,
Department of Medicine, Veterans Administration Hospital, Minneapolis, Minnesota 55417, U.S.A.
L. R. PETERSON
D. N. GERDING
ANTIBIOTIC ANTAGONISM AND SYNERGY
SiR,—Your editorial on antibiotic antagonism and synergy (July 8, p. 80) noted that clinical antagonism seems to be irrelevant in Haemophilus influenza meningitis treated with a combination of ampicillin and chloramphenicol. This is surprising in view of the report by Lindbert et al. 8 showing the incidence of long-term sequelx of H. influenzae meningitis in childhood to be increased after combination therapy with ampicillin and chloramphenicol. They noted residual deficits in 27% of 82 patients, with more than half having hearing loss alone. Among 11 children treated with ampicillin and chloramphenicol in 1. 2.
Gillett, A. P., Wise, R. Lancet, 1978, i, 962. Verwey, W. F., Williams, H. R. Antimicrob. Ag. Chemother. 1962-63, p. 476.
Peterson, L. R., Gerding, D. N., Zinneman, H. H., Moore, B. M. ibid. 1977, 11, 993. 4. Peterson, L. R., Hall, W. H., Zinneman, H. H., Gerding, D. N.J. infect. Dis. 1977, 136, 778. 5. Gerding, D. N., Peterson, L. R., Salomonson, J. K., Hall, W. H., Schierl, 3.
6. 7. 8.
E. A. ibid. D.
(in the press).
N., Peterson, L. R., Legler, D. C., Hall, W. H., Schierl, E. A. Antimicrob. Ag. Chemother. (in the press). Peterson, L. R., Gerding, D. N. ibid. (in the press). Lindberg, J., Rosenthal, U., Nylen, O., Ringner, A. Pediatrics, 1977, 60, 1.
Gerdmg,
Departments
AJAY MURDIA VISHNU MATHUR L. K. KOTHARI K. P. SINGH
CORYNEBACTERIUM SPP IN HUMAN DISEASE
SIR,-Dr Vale and Dr Scott’ described the incidence of Corynebacterium bovis in human disease. The National Collection of Type Cultures (N.C.T.C.) has long had an interest in isolates of Corynebacterium spp. involved in human disease.2-4 Organisms of this group, other than C. diphtheria, comprise about 20% of the miscellaneous bacteria
sent to the N.C.T.C. for identification each year. 172 strains of coryneforms were received for identification in the period 1965-75, of which 35% were identified to species level, 43% to genus or possible species, and 22% were unidentified. Identification was attempted using methods and tables given in Cowanand information derived from Bergey’s Manualb and specialist papers, as well as the records of the N.C.T.C. on the cultures that it maintains. The low identification-rate is, in part, due to the poor classification of this group of microorganismse.g., various authors seem to have described different bacteria under the name C. bovis. A total of 15 strains of C. bovis or C. bovis-like organisms have been submitted to the N.C.T.C. for identification since 1965, including those described by Vale and Scott. Other Corynebacterium spp. received include: 2 C. aquaticum, 8 C. haemolyticum, 1 C. hofmannii, 1 C. minutissimum, 1 C. ovis, 6 C. pyogenes, 2 C. renale, 2 C. ulcerans, 29 strains which were very similar to one or other of these species, and 18 strains very similar to C. belfanti (10 strains), C. equi (2 strains), and C. xerosis (6 strains). In addition, 5 strains were identified as Brevibacterium spp. 50 strains could not be identified with named taxa, but 38 of these could be grouped into 6 "new" taxa.4 These bacteria were isolated from a wide variety of human specimens (blood cultures, 40 strains; urogenital tract, 7; pus, 10; cerebrospinal fluid, 7; ear, nose, and throat, 12; limbs, 16). The available details of the clinical conditions concerned were often scanty and no correlation was found between any particular syndrome and any one species or taxon, nor could the possible pathogenic effect of the isolates be evaluated in many of the cases. The genus Brevibacterium has rarely been implicated in human disease and Pitcherhas suggested that many skin bacteria may be more correctly placed in Brevibacterium than in Corynebacterium. Pitcher’s work and that of Hill et al.4 emphasise the difficulty of identifying many strains of coryneform-like bacteria of human origin. These results, together with those of Vale and Scott, suggest that coryneform-like bacteria do cause human disease and should not be ignored if isolated. J. E. HINE National Collection of Type Cultures, L. R. HILL Central Public Health Laboratory, London NW9 5HT S. P. LAPAGE
1. Vale, J. A., Scott, G. W. Lancet, 1977, ii, 682. 2. Bowie, I. S., Hill, L. R., Lapage, S. P. Second International Symposium on Rapid Methods and Automation in Microbiology, Cambridge, September 19-25, 1976; p. 91. Oxford 1977. 3. Hine, J. E., Hill, L. R., Lapage, S. P. ibid. p. 104. 4. Hill, L. R., Lapage, S. P. and the late Bowie, I. S. in Coryneform Bacteria (edited by I. J. Boufield and A. G. Callely); p. 181. London, 1978. 5. Cowan, S. T. Cowan and Steel’s Manual for the Identification of Medical Bacteria. Cambridge, 1974. 6. Buchanan, R. E., Gibbons, N. E. Bergey’s Manual of Determinative Bacteriology. Baltimore, 1974. 7. Pitcher, D. G. Br. J. Dermat. 1978, 98, 363.
PROTEIN BINDING AND ANTIBIOTIC CONCENTRATIONS
SIR,-Dr Gillett and Dr Wise1 claim to have demonstrated that protein binding of drugs has no effect on the concentration measured in a tissue space and that "the penetration of antibiotic into tissue fluid does not depend on the fraction of free drug in the blood". The technique Gillett and Wise used to abrade the skin and cause no "significant bleeding" means that the discs will contain a high protein filtrate of serum, or serum itself. Verwey and Williams have demonstrated rapid equilibrium between free plasma drug levels and peripheral lymph, indicating rapid free drug diffusion.2 We have found that serum proteins can bind large amounts of antibiotic.34Therefore, it is highly likely that the protein in Gillett and Wise’s discs, being mainly albumin, also significantly bound the antibiotics tested. They found tissue-fluid levels similar to serum levels because they were, in effect, measuring serum in their tissue-fluid model. We have demonstrated that the free drug level in serum is important and that the total concentration of a drug in a tissue fluid can be predicted from the serum concentration, the antibiotic serum protein binding, and the antibiotic protein binding in the tissue fluid being evaluated. The following formula has been highly predictive under equilibrium conditions in animal models: 5-7
[C.] . F, [Cc ]=tissue fluid drug concentration
=serum drug concentration
F.=free fraction of drug in serum Fe =free fraction of drug in tissue fluid. If protein binding in serùm and tissue fluid is identical then .F. =R and the tissue-fluid drug concentration will equal the serum concentration (exactly as demonstrated by Gillett and Wise). Our latest study has shown this to be true for both high and low protein containing extravascular fluid.7 Therefore, while we agree that high serum-protein binding of antibiotics is not necessarily a detriment, we believe that the concepts presented by Gillett and Wise are incorrect and that they further obscure the already confusing issue of antibioticprotein interactions. Infectious Disease Section,
Department of Medicine, Veterans Administration Hospital, Minneapolis, Minnesota 55417, U.S.A.
L. R. PETERSON
D. N. GERDING
ANTIBIOTIC ANTAGONISM AND SYNERGY
SiR,—Your editorial on antibiotic antagonism and synergy (July 8, p. 80) noted that clinical antagonism seems to be irrelevant in Haemophilus influenza meningitis treated with a combination of ampicillin and chloramphenicol. This is surprising in view of the report by Lindbert et al. 8 showing the incidence of long-term sequelx of H. influenzae meningitis in childhood to be increased after combination therapy with ampicillin and chloramphenicol. They noted residual deficits in 27% of 82 patients, with more than half having hearing loss alone. Among 11 children treated with ampicillin and chloramphenicol in 1. 2.
Gillett, A. P., Wise, R. Lancet, 1978, i, 962. Verwey, W. F., Williams, H. R. Antimicrob. Ag. Chemother. 1962-63, p. 476.
Peterson, L. R., Gerding, D. N., Zinneman, H. H., Moore, B. M. ibid. 1977, 11, 993. 4. Peterson, L. R., Hall, W. H., Zinneman, H. H., Gerding, D. N.J. infect. Dis. 1977, 136, 778. 5. Gerding, D. N., Peterson, L. R., Salomonson, J. K., Hall, W. H., Schierl, 3.
6. 7. 8.
E. A. ibid. D.
(in the press).
N., Peterson, L. R., Legler, D. C., Hall, W. H., Schierl, E. A. Antimicrob. Ag. Chemother. (in the press). Peterson, L. R., Gerding, D. N. ibid. (in the press). Lindberg, J., Rosenthal, U., Nylen, O., Ringner, A. Pediatrics, 1977, 60, 1.
Gerdmg,
