Letters to the Editor Isolates of Group F Streptococcus
Received May 19, 1977; received revised manuscript July 5, 1977; accepted for publication July 5, 1977. Key words: Streptococcus, group F. Address reprints to Dr. Ingham.
HARRY R. INGHAM, M.B.,
CH.B.,
M.R.C. PATH., DIP. BACT. PENELOPE R. SISSON, B.SC.
Department of Microbiology Public Health Laboratory Institute of Pathology General Hospital Westgate Road Newcastle upon Tyne England NE4 6BE
Table 1. Sources of Isolates Wounds Abdominal Other Genitourinary Vagina Urinary tract Abscesses Dental Brain Liver Perianal Suprapubic Appendix
12 2 18 2 3 2
TOTAL 44
References 1. Bannatyne RM, Randall C: Ecology of 350 isolates of group F streptococcus. Am J Clin Pathol 67:184-186, 1977 2. Colman G, Williams REO: Taxonomy of some human viridans streptococci, Streptococci and Streptococcal Diseases, Recognition, Understanding, and Management. Edited by Wannamaker LW, Matsen JM. New York, Academic Press, 1972, pp 288-291 3. Ingham HR, Hood FJC, Bradnum P, et ai: Metronidazole compared with penicillin in the treatment of acute dental infections. Br J Oral Surg 14: 264-269, 1977
The Authors' Reply To the Editor:—We are sorry if we implied that our nonhemolytic group F streptococci were all recovered aerobically (although we did not actually claim this). In fact, some of them were Received and accepted for publication June 8, 1977. Address reprint requests to Dr. Bannatyne.
obtained from blood agar plates incubated anaerobically with 10% C0 2 . We did not attempt to determine whether any of these isolates grew only anaerobically with C0 2 . Perhaps we would have confirmed Dr. Ingham'sfindingsif we had. The equivalent effectivenesses of metronidazole and penicillin in acute dental infections is persuasive evidence 798
of the importance of obligate anaerobes in the etiology of this condition. But this does not exclude a role for metronidazole-resistant organisms in dental infections—a good example is actinomycosis. In the three cases of submandibular abscess following dental extractions that we alluded to, anaerobic organisms were energetically sought but not found. Only group F strepto-
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
To the Editor:—We read with interest the recent article reporting the results of a study of the ecology of group F streptococci,1 but feel that the statement that nonhemolytic group F strains of Streptococcus milleri grow well under aerobic conditions on blood agar and lack a characteristic caramei smell merits comment. In a recent study in this laboratory (to be published), 44 strains of streptococci were isolated from a variety of sites (Table 1). All the isolates were selected initially as metronidazole-resistant, nonhemolytic streptococci growing anaerobically, but not aerobically even after five days at 37 C, on 5% blood agar. On subculture on the same medium they grew very poorly in 5% carbon dioxide, but without difficulty in 10% carbon dioxide. Thirtynine of the strains had a definite caramel odor and 40 (90%) carried the group F antigen. Biochemically all were iden-
tified as S. milleri according to the criteria of Colman and Williams.2 These differences may reflect variations in the methods between the laboratories, but it is interesting that initial selection on the basis of a requirement for carbon dioxide for growth under aerobic conditions yielded a homogeneous group of organisms with the biochemical characteristics of S. milleri. Colman and Williams2 reported that only a third of S. milleri strains were group F, the remainder being group A, C, or G, or non-groupable. Undoubtedly group F strains of S. milleri have been shown to be pathogenic in the brain and liver, but caution should be exercised with regard to their role in acute dental infections in view of recent work implicating obligate anaerobes as the primary pathogens in these conditions.3
Received May 19, 1977; received revised manuscript July 5, 1977; accepted for publication July 5, 1977. Key words: Streptococcus, group F. Address reprints to Dr. Ingham.
HARRY R. INGHAM, M.B.,
CH.B.,
M.R.C. PATH., DIP. BACT. PENELOPE R. SISSON, B.SC.
Department of Microbiology Public Health Laboratory Institute of Pathology General Hospital Westgate Road Newcastle upon Tyne England NE4 6BE
Table 1. Sources of Isolates Wounds Abdominal Other Genitourinary Vagina Urinary tract Abscesses Dental Brain Liver Perianal Suprapubic Appendix
12 2 18 2 3 2
TOTAL 44
References 1. Bannatyne RM, Randall C: Ecology of 350 isolates of group F streptococcus. Am J Clin Pathol 67:184-186, 1977 2. Colman G, Williams REO: Taxonomy of some human viridans streptococci, Streptococci and Streptococcal Diseases, Recognition, Understanding, and Management. Edited by Wannamaker LW, Matsen JM. New York, Academic Press, 1972, pp 288-291 3. Ingham HR, Hood FJC, Bradnum P, et ai: Metronidazole compared with penicillin in the treatment of acute dental infections. Br J Oral Surg 14: 264-269, 1977
The Authors' Reply To the Editor:—We are sorry if we implied that our nonhemolytic group F streptococci were all recovered aerobically (although we did not actually claim this). In fact, some of them were Received and accepted for publication June 8, 1977. Address reprint requests to Dr. Bannatyne.
obtained from blood agar plates incubated anaerobically with 10% C0 2 . We did not attempt to determine whether any of these isolates grew only anaerobically with C0 2 . Perhaps we would have confirmed Dr. Ingham'sfindingsif we had. The equivalent effectivenesses of metronidazole and penicillin in acute dental infections is persuasive evidence 798
of the importance of obligate anaerobes in the etiology of this condition. But this does not exclude a role for metronidazole-resistant organisms in dental infections—a good example is actinomycosis. In the three cases of submandibular abscess following dental extractions that we alluded to, anaerobic organisms were energetically sought but not found. Only group F strepto-
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
To the Editor:—We read with interest the recent article reporting the results of a study of the ecology of group F streptococci,1 but feel that the statement that nonhemolytic group F strains of Streptococcus milleri grow well under aerobic conditions on blood agar and lack a characteristic caramei smell merits comment. In a recent study in this laboratory (to be published), 44 strains of streptococci were isolated from a variety of sites (Table 1). All the isolates were selected initially as metronidazole-resistant, nonhemolytic streptococci growing anaerobically, but not aerobically even after five days at 37 C, on 5% blood agar. On subculture on the same medium they grew very poorly in 5% carbon dioxide, but without difficulty in 10% carbon dioxide. Thirtynine of the strains had a definite caramel odor and 40 (90%) carried the group F antigen. Biochemically all were iden-
tified as S. milleri according to the criteria of Colman and Williams.2 These differences may reflect variations in the methods between the laboratories, but it is interesting that initial selection on the basis of a requirement for carbon dioxide for growth under aerobic conditions yielded a homogeneous group of organisms with the biochemical characteristics of S. milleri. Colman and Williams2 reported that only a third of S. milleri strains were group F, the remainder being group A, C, or G, or non-groupable. Undoubtedly group F strains of S. milleri have been shown to be pathogenic in the brain and liver, but caution should be exercised with regard to their role in acute dental infections in view of recent work implicating obligate anaerobes as the primary pathogens in these conditions.3
