Streptococcus milleri is not an uncommon pyogenic pathogen

Abstract EN

Background : Members of Streptococcus milleri group (SMG) may be unrecognized or misidentified in many laboratories, and their clinical role in causing invasive pyogenic infections may be underestimated.

Objective : To study the bacteriological, antimicrobial susceptibility, and clinical significance of Streptococcus milleri (SMG).

Design : A prospective study.

Setting: King Hussein Medical Centre, Amman, Jordan.

Method : Seventy-three SMG isolated between November 2003 to October 2006 were examined.

The phenotypic characteristics and hemolytic patterns of the bacterial colonies were noted.

Lancefield sero-grouping was determined by rapid latex agglutination slide test.

All isolates were tested using Vitek GPI System for identification.

Antimicrobial susceptibility testing was performed by both disk diffusion method and Vitek GPS System.

The clinical conditions associated with SMG isolates were recorded.

Result : All SMG colonies consistently produced characteristic caramel-like odor.

They showed variable hemolysis and sero-grouping patterns.

Forty (54.8%) isolates were non-hemolytic.

Forty-One out of 73 (56.2%) were nongroupable.

Only 13 (17.8%) isolates were identified by the Vitek GPI system.

SMG isolates were resistant to gentamicin but sensitive to all the other tested antimicrobial agents.

Cervical abscess was the commonest clinical presentation in this study.

Conclusion : SMG is a significant cause of serious invasive infections.

Awareness of SMG by microbiologists and clinicians is important and may aid in laboratory and clinical diagnosis and better patient management.

This is the first report from Jordan demonstrating the bacteriological, antimicrobial susceptibilities, and clinical significance of 73 isolates in our hospital.