Trend of Invasive Streptococcus agalactiae at Tertiary Care Hospital in Japan

Streptococcus agalactiae causes various severe infectious diseases such as sepsis, meningitis, and streptococcal toxic shock-like syndrome. Though Streptococcus agalactiae infection has been increasing recently, the comprehensive characteristic investigation of invasive Streptococcus agalactiae isolated in tertiary care hospitals has not been nearly performed in Japan. In this study, we investigated the clinical characteristics and antimicrobial susceptible patterns of 88 Streptococcus agalactiae isolated at two tertiary care hospitals during 2009-2015 in Japan. There was no significant differences between genders in our study. Two-third Streptococcus agalactiae were isolated from over age 60. Total mortality rate was 19% and invasive Streptococcus agalactiae-associated death cases have occurred every year after 2011. All Streptococcus agalactiae were completely susceptible toampicillin. Total non-susceptible rates of erythromycin, minocycline, levofloxacin and trimethoprim-sulfamethoxazole in this study were approximately 30%, 44%, 37%, and 7%, respectively. Our results suggest the need for continuous antimicrobial susceptibility survey of Streptococcus agalactiae.

Analysis of Pyelonephritis-Associated Beta Hemolytic Streptococcus in Japan

Pyelonephritis is an inflammation of the kidney tissue, calyces, and renal pelvis. It is commonly caused by bacterial infection that has spread up the urinary tract. Common bacteria are Escherichia coli and Enterococcus faecalis. Beta hemolytic streptococci also cause pyelonephritis. Beta hemolytic streptococcus such as Streptococcus agalactiae, and S. dysgalactiae subsp. equisimilis, when grown on blood-agar, produce complete hemolysis around each colony, usually cause severe infections including many cases of cellulitis, pneumonia, meningitis and sepsis. However the analysis of pyelonephritis causing beta hemolytic streptococcus has seldom been investigated. In this study, we tried to clarify the relationship between beta hemolytic streptococcus and pyelonephritis patient in Japan. We investigated beta hemolytic streptococcus isolated from pyelonephritis patient at two tertiary care hospitals in the central region of Japan by analyzing the background and antimicrobial susceptibility of beta hemolytic streptococcus. We recovered total sixteen beta hemolytic streptococcus in nine years. In pyelonephritis patients, beta hemolytic streptococcus was isolated from 9 S. agalactiae and 7 S. dysgalactiae subsp. equisimilis, respectively. The numbers of streptococci from female patients were more than those from male patients. Bacteria were not isolated from under 30 year patients. All S. dysgalactiae subsp. equisimilis were isolated from 60-year-age patients. About one fifth of beta hemolytic streptococcus had erythromycin and minocycline-resistant ability. Four beta hemolytic streptococci that were all S. agalactiae, had levofloxacin-resistant ability. Only one S. agalactiae had trimethoprim-sulfamethoxazole-resistant ability. Ampicillin was effective against all beta hemolytic streptococci. In our results, beta hemolytic streptococcus caused pyelonephritis in aged people and the quarter of these bacteria had some antibiotics resistance.