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[Clinical significance of Streptococcus milleri isolated from various suppurative lesions]
1Department of Clinical Laboratory, Tamana Central Hospital.
Abstract:
Seventy-one strains of Streptococcus milleri were isolated from 68 patients admitted to Tamana Central Hospital. (1985.2-1989.1) S. milleri was isolated from the following specimens: sputum (15 strains), urine (10), ascites (9), postoperative wound (9), pleural effusate (6), bile (5), genital discharge (3), aspirated fluid from lung abscess (2) and others (12). In 12 patients (18%), S. milleri was isolated in pure culture and in 56 patients (82%) as part of a mixed flora. Other bacteria isolated in association with S. milleri were obligate anaerobes (41%), Gram-negative rods (40%), Gram-positive cocci (16%) and others (3%). In 71 strains of S. milleri, 9 strains (13%) were beta-haemolytic, 62 (87%) were alpha-haemolytic (week) or non-haemolytic. In 68 patients, type specific male-female ratio was 15:9 for S. milleri I, 20:15 for II and 1:8 for III respectively. The patient's age ranged from 7 to 86 years and 75% of patients were more than 50 years old. In respiratory infection, 10 cases (pyothorax, 6; pneumonia, 3; lung abscess, 1) were related to S. milleri infection and considered clinically significant. 8 cases had underlying disease, however, 2 cases (pyothorax, lung abscess) had no underlying disease. In these 2 cases, S. milleri was isolated in pure culture. Successful treatment of these ten cases usually required either antibiotic therapy or drainage of the lesion. S. milleri was isolated from various clinical specimens and some cases were associated with serious infections. S. milleri was more commonly associated with suppurative infections than other viridans group streptococci. S. milleri may therefore have different characteristics which other streptococcal species of normal flora have not.
Insights
Streptococcus milleri is frequently isolated from various clinical samples, often as part of mixed infections. This bacterium is notably linked to suppurative infections, suggesting unique pathogenic characteristics.
Area of Science:
- Medical Microbiology
- Clinical Bacteriology
Background:
- Streptococcus milleri group (S. milleri) bacteria are part of the normal flora but can cause infections.
- Understanding the prevalence and clinical significance of S. milleri is crucial for effective patient management.
Observation:
- S. milleri was isolated from 68 patients across diverse specimens including sputum, urine, and wounds.
- The bacterium was found in pure culture in 18% of cases and mixed flora in 82%, frequently with anaerobes and Gram-negative rods.
- Beta-hemolytic strains constituted 13% of isolates, while 87% were alpha-hemolytic or non-hemolytic.
Findings:
- S. milleri was implicated in 10 clinically significant respiratory infections, such as pyothorax and pneumonia.
- Two cases of pyothorax and lung abscess caused by S. milleri in pure culture occurred without underlying disease.
- Successful treatment involved antibiotics and/or lesion drainage.
Implications:
- S. milleri demonstrates a higher association with suppurative infections compared to other viridans streptococci.
- These findings suggest S. milleri possesses distinct pathogenic traits differentiating it from commensal streptococci.
- Further research into S. milleri's unique characteristics is warranted to understand its role in disease.