Accurate and rapid diagnosis of neonatal septicemia is highly warranted
because of high associated morbidity and mortality. Blood culture serves as a routine
method for diagnosis of bacterial sepsis. However, it sometimes takes ≥ 72 hours for the
results, with low sensitivity. Full automated blood culture method is superior to
conventional methods in terms of speed and sensitivity. The polymerase chain reaction–
based detection of 16S rRNA has reduced the laboratory turnaround time and has good
sensitivity. Objectives: The aim of this study was to compare automated blood culture
and amplification of 16srRNA gene by PCR in detection of aerobic bacterial infection in
blood samples of hospitalized neonates with suspected neonatal sepsis and to determine
the most common types of bacteria causing neonatal sepsis. Methodology: Blood
samples collected from 40 neonates clinically suspected as neonatal sepsis were
subjected to bacterial identification through automated blood culture by BacT/ALERT
PF Plus Culture Bottles, and bacterial detection of 16S rRNA gene by PCR. Results: Out
of 40 neonatal blood samples with suspected sepsis, 37(92.5%) neonates showed
concordance between automated blood culture and PCR; 17(42.5%) showed positive
results while 20 (50%) gave negative results by both methods. The remaining 3 cases
(7.5%) were positive only by PCR. PCR sensitivity, specificity, positive and negative
predictive values were 100%, 86.9%, 85% and 100% respectively. So, accuracy of PCR
in relation to automated blood culture is 92.5%. The most common pathogens in cases of
early onset neonatal sepsis were Klebsiella pneumoniae (7/15, 46.7%) followed by
Streptococcus agalactiae (1/15, 6.6%) while the most common pathogens found in cases
of late onset neonatal sepsis were Klebsiella pneumoniae and coagulase negative
staphylococci (4/25,16% for each) then Staphylococcus aureus (1/25, 4%). Conclusion:
16S rRNA PCR showed accurate rapid diagnosis with higher sensitivity in diagnosis of
neonatal septicemia. Klebsiella peumoniae was the main causative bacteria in early
onset neonatal sepsis and late onset neonatal sepsis.
|
