Background : To delineate the changes in the causative agents of neonatal sepsis and
their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang
University Hospital during the past 10 years.
Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of
Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of
neonatal sepsis were sorted and included in the study. The study period was divided into
Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and
their antimicrobial susceptibilities.
Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%})
among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates)
were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170
patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when
the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the
proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that
neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram
positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase
negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus
aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%),
Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida
parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter
baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial
susceptibilities of CNS and S. aureus to methicillin and the first generation cephalosporins were decreased in Period B compare to Period A, those to aminoglycosides were
increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae,
Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared
to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins
were low in both Periods A and B, those to tobramycin and gentamicin were increased
in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole
were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin,
penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin
resistant strains were not identified.
Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU
and nursery of the Hanyang University hospital was 1.1%, and the most common causitive
agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line
drugs decreased in the later half of the study period with no vancomycin resistant isolates
identified. Group B Streptococcus known to be the most common agent causing neonatal
sepsis was not identified, and K. pneumoniae was isolated more commonly during the later
half of the study period without decreased antimicrobial susceptibilities.
Background : To delineate the changes in the causative agents of neonatal sepsis and
their antimicrobial susceptibilities in the neonatal intensive care unit and nursery of Hanyang
University Hospital during the past 10 years.
Methods : Hospital records of 15,144 patients hospitalized at the NICU and nursery of
Hanyang University Hospital from 1989 to 1998 were reviewed and neonates diagnosed of
neonatal sepsis were sorted and included in the study. The study period was divided into
Period A(the first 5 years) and Period B(the second 5 years) to analyse causative agents and
their antimicrobial susceptibilities.
Results : Neonatal sepsis was diagnosed in 170 patients(1.1%{Period A 1.2%, Period B 1.0%})
among the total of 15,144 inpatients. Two hundred isolates(Period A 109 isolates, Period B 91 isolates)
were identified in 186 blood cultures(Period A 99 cultures, Period B 87 cultures) from 170
patients(Period A 91 patients, Period B 79 patients). The average age at the onset of the disease, when
the initial blood culture was drawn, was 12.3 days old(Period A 8.8 days, Period B 16.3 days), and the
proportion of the early onset disease was 34.7% in Period A and 23.0% in Period B, indicating that
neonatal sepsis developed earlier during Period A. Among the isolated organisms including Gram
positive bacteria[132(66.0%)], Gram negative bacteria [60(30.0%)], and fungi[8(4.0%)], coagulase
negative Staphylococcus(CNS) was the most common organism(69/34.5%), followed by Staphylococcus
aureus(36/18.0%), Klebsiella pneumoniae(17/8.5%), Enterococcus(12/6.0%), Enterobacter cloacae(8/4.0%),
Escherichia coli(6/3.0%), and Pseudomonas aeruginosae(5/2.5%). The isolated fungi were Candida
parapsilosis, Candida albicans, and Trichosporon pullulans. CNS, S. aureus and Acinetobacter
baumannii were isolated more frequently in Period A compared to Period B. Antimicrobial
susceptibilities of CNS and S. aureus to methicillin and the first generation cephalosporins were decreased in Period B compare to Period A, those to aminoglycosides were
increased in Period B, and vancomycin resistant strains were not identified. K. pneumoniae,
Enterococcus, E. coli, and P. aeruginosa were isolated less frequently in Period B, compared
to Period A. For K. pneumoniae, antimicrobial susceptibilities to the first generation cephalosporins
were low in both Periods A and B, those to tobramycin and gentamicin were increased
in Period B, and those to amikacin, ceftriaxone, and trimethoprim-sulfamethoxazole
were high in both Periods A and B. Antimicrobial susceptibilities of Enterococcous to ampicillin,
penicillin, and the first generation cephalosporins were decreased in Period B, but vancomycin
resistant strains were not identified.
Conclusion : The occurrence rate of neonatal sepsis during the past 10 years in the NICU
and nursery of the Hanyang University hospital was 1.1%, and the most common causitive
agents were CNS and S. aureus, to which the antimicrobial susceptibilities to the first line
drugs decreased in the later half of the study period with no vancomycin resistant isolates
identified. Group B Streptococcus known to be the most common agent causing neonatal
sepsis was not identified, and K. pneumoniae was isolated more commonly during the later
half of the study period without decreased antimicrobial susceptibilities.