Abstract:

Objective

To explore the clinical characteristics of severe Streptococcus agalactiae infection in small infants.

Methods

Clinical data of hospitalized infants with Streptococcus agalactiae positive in blood culture or cerebrospinal fluid bacterial culture from January 1st， 2016 to December 31st，2023 in the Pediatric Intensive Care Unit， Children's Hospital Affiliated to Capital Institute of Pediatrics was analyzed， retrospectively.

Results

Total of 23 infants were included， the ratio of male to female was 14∶9；the diagnostic age was 5-101 days， the infants under 3 months accounted for 95.7% （22 cases）.There were 13 cases （56.5%） diagnosed as septicemia and complicated with purulent meningitis， while 4 cases （17.4%）only with septicemia and 6 cases （26.1%） only with purulent meningitis.There were 12 cases （52.2%） of septic shock and 12 cases （52.2%） of multiple organ failure.Total of 8 cases （34.8%） were complicated with subdural effusion， 4 cases （17.4%） complicated with ventricular meningitis and 7 cases （30.4%） complicated with hydrocephalus.The hospitalization duration was 28 hours to 74 days.Total of 12 cases were cured，3 cases died and 8 cases were left with neurological sequelae.Compared with the cured group， the poor prognosis group had lower white blood cell count ［1.9 （1.1， 6.6） × 10⁹/L vs.11.3 （3.6， 16.1） × 10⁹/L： Z =-2.585， P = 0.010］ and lower platelet count ［152 （78， 233） × 10⁹/L vs.301 （212， 412） × 10⁹/L： Z =-2.523，P = 0.012］， higher white blood cell count in cerebrospinal fluid ［1 425 （290， 3 500） × 10⁶/L vs. 153 （5， 1 495） ×10⁶/L： Z =-2.093， P = 0.036］ at the beginning of illness； and had lower cerebrospinal fluid glucose ［0.2 （0.1，0.3） mmol/L vs.2.6 （0.7， 4.1） mmol/L： Z =-3.171， P = 0.002］， higher cerebrospinal fluid protein ［5 226 （2 935， 6 892） mg/L vs.937 （558， 2 997） mg/L： Z =-3.077， P = 0.002］， longer prothrombin time ［17.8 （14.5， 19.4） s vs.12.9 （11.9，15.0） s： Z =-3.016， P = 0.003］， longer activated partial thromboplastin time ［53.6 （44.2， 102.3） s vs.40.6（37.2， 47.8） s， Z =-2.893， P = 0.004］， lower pH ［7.3 （7.2， 7.4） vs.7.4 （7.3， 7.4）］： Z =-2.585， P = 0.010］，higher proportion of three or more antibiotics application （81.8% vs.33.3%： χ² = 5.490， P = 0.019）， higher proportion of component blood transfusion （81.8% vs. 41.7%： χ² = 3.884， P = 0.049） and shorter 28 day-non-ICU hospitalization duration ［0 （0， 1.0） d vs. 8.5 （0.3， 12.5） d： Z =-2.250， P = 0.024］.

Conclusions

The clinical manifestations of infection in small infants caused by Streptococcus agalactiae are severe， and they are sensitive to commonly used penicillin and cephalosporins.However， central nervous system involvement can easily lead to serious complications and residual neurological sequelae.

Key words: Small infant, Streptococcus agalactis, Severe, Septicemia, Meningitis, Septic shock