[Clinical and bacteriological significance of the Streptococcus milleri group in deep neck abscesses].
Streptococcus constellatus, S. intermedius, and S. anginosus, the three species of the S. milleri group, form part of the normal flora most commonly found in the mouth, throat, gastrointenstinal tract, and genital tract. The S. milleri group has become known as an important pathogen in abscess disease, but little attention has been paid to their role in deep neck abscesses. We have treated 9 patients with deep neck abscesses relating to the S. milleri group since 1991, and regarded this group as an important pathogen also in these abscesses. We studied the frequency of the S. milleri group isolated from deep neck abscesses in our cases and from the literature and discuss clinical significance and bacteriological pathogenesis. Cases numbered 27 treated at our facility since 1991 and 200 cases reported in the Japanese literature since 1990. Of our 9 cases, 4 originated from acute pharyngitis, 3 from peritonsillar abscesses, and 2 from odontogenic infection. Serious complications such as mediastinitis, cervical necrotizing fasciitis, sepsis accompanied by disseminated intravascular coagulation, and spondylitis of the cervical vertebrae were seen in 4 cases. Among organisms isolated, the S. milleri group appeared to be a pathogen contributing to abscess formation and to serious complications. The genus Streptococcus was most frequently isolated both in our 27 cases (66.7%) and the 200 in the literature (45.5%). Among species of the genus Streptococcus, the S. milleri group numbered the highest in our cases at 33.3% but only 8.5% in the literature. Cases in the literature, however, contained many unknown species of Streptococci--31.5% vs. 18.5% in our cases. alpha-streptococcus was frequently reported in the literature among unknown species of Streptococci--36 of 63. Culture-negative cases were also numbered more in the literature than in our case--29.0% vs. 18.5%. Special conditions and procedures are required to suitably isolate and detect the S. milleri group. Since not all facilities use identical techniques in routine bacteriological examination, a considerable number of the S. milleri group could be missed in unknown species of Streptococci or alpha-streptococcus and culture-negative cases. The detailed pathogenesis of the S. milleri group remains to be clarified. Infection by normal flora on mucosa is thought to occur due to an imbalance between organisms and host defense in deep neck abscesses. Some strains of the S. milleri group have been reported to produce many tissue-destroying enzymes such as collagenase and hyaluronidase. The co-existence of the S. milleri group with some anaerobe strains has also been suggested to accelerate inflammation. We discuss the mechanism inducing the massive release of cytokines through T cell response to certain exotoxins produced by S. milleri group, as reported in toxic shock-like syndrome due to the group A beta-streptococcus and in alpha-streptococcal shock syndrome due to viridans streptococci (alpha-streptococci).
Department of Otorhinolaryngology, University of Occupational and Environmental Health, School of Medicine, Fukuoka.
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T
Fujiyoshi
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Okasaka
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M
Yoshida
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K
Makishima
D000038:Abscess / Q000209:etiology / Q000382:microbiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009333:Neck; D000039:Peritonsillar Abscess / Q000150:complications; D010612:Pharyngitis / Q000150:complications; D013291:Streptococcus / Q000302:isolation & purification*