Related Experiment Videos
Streptococcus mitis infection in newborns
1Department of Pediatrics and Communicable Diseases, University of Michigan Medical Center, Ann Arbor 48109-0254.
Abstract:
Although neonatal infections caused by Streptococcus viridans have been suggested to be less severe than those caused by classic neonatal pathogens, little is known about neonatal infections caused by specific species within this group of bacteria. We report six infants who had S. mitis isolated from blood culture. All were infected at < or = 3 days of age; five of the mothers had perinatal risk factors for neonatal sepsis. Five infants were preterm and three had birth weights < or = 2500 gm. Hematologic abnormalities were common. Two died as a result of the infection. Antibiotic susceptibility testing of four isolates revealed resistance to penicillin and ampicillin in three and resistance to gentamicin in two. In vivo resistance was not observed. S. mitis is not part of normal skin flora, should not be assumed to be a contaminant, and can cause severe neonatal disease. If S. mitis or S. viridans are recovered from a normally sterile body site and the patient fails to improve with penicillin therapy, it seems prudent to switch to vancomycin until susceptibility results are available.
Insights
Streptococcus mitis can cause severe neonatal infections, contrary to previous assumptions about viridans group Streptococcus. Early identification and appropriate antibiotic treatment, potentially including vancomycin, are crucial for infant survival.
Area of Science:
- Neonatal Medicine
- Infectious Diseases
- Microbiology
Background:
- Neonatal infections caused by viridans group Streptococcus are often considered less severe than those from classic pathogens.
- Limited data exists on the specific clinical impact of individual Streptococcus viridans species in neonates.
Purpose of the Study:
- To investigate the clinical significance and outcomes of neonatal infections caused by Streptococcus mitis.
- To assess the antibiotic susceptibility patterns of S. mitis isolates from neonatal sepsis cases.
Main Methods:
- Case series reporting on six infants with S. mitis isolated from blood cultures.
- Analysis of patient demographics, clinical presentation, hematologic findings, and treatment outcomes.
- In vitro antibiotic susceptibility testing of bacterial isolates.
Main Results:
- All six infants were infected within the first three days of life, with five being preterm and three having low birth weights.
- Hematologic abnormalities were frequently observed, and two infants succumbed to the infection.
- Antibiotic susceptibility testing revealed resistance to penicillin and ampicillin in three isolates and gentamicin resistance in two.
Conclusions:
- Streptococcus mitis, not typically part of normal skin flora, can cause severe neonatal disease and should not be dismissed as a contaminant.
- Prompt recognition and consideration of alternative antibiotics like vancomycin are recommended for severe S. mitis or S. viridans neonatal infections unresponsive to penicillin.