Impact of a rapid molecular test for positive blood cultures from neonatal intensive care patients on clinical management: a retrospective audit

Abstract

Background: Both Staphylococcus aureus and coagulase negative Staphylococci are common causes of late-onset neonatal sepsis in the neonatal intensive care unit (NICU), usually relating to intravascular access device infections.

Aims: This project aimed to review the impact on antimicrobial treatment and clinical outcome in the NICU setting, of the introduction of the Xpert MRSA/SA BC test (Cepheid, USA) for the identification of staphylococci in blood cultures.

Methods: A retrospective audit was carried out of the pre- and post-intervention periods; the intervention was the introduction of the Xpert MRSA/SA BC test.

Results: In total, 88 neonates had positive blood cultures with Staphylococcus spp., comprising 42 neonates in the pre-intervention and 46 in the post-intervention groups. The pre-intervention group had a higher birth weight (1.541 kg vs. 1.219 kg, p = 0.05) and higher platelet count (288 vs. 224 × 10⁹/L, p = 0.05). There was a trend towards a shorter duration of antimicrobial therapy in term infants and in the length of admission; however, this was not statistically significant (p = 0.2). All of the nine infants post-intervention with significant bacteraemia (S. aureus =3, CoNS =6) were changed to the optimal antimicrobial at the time the result was available.

Conclusions: This study shows that the introduction of the Xpert MRSA/SA BC test can lead to a reduction in the length of admission and duration of antimicrobials in term infants; however, the difference was not statistically significant. All nine infants with clinically significant bacteraemia were treated with the appropriate antimicrobial when the Xpert MRSA/SA BC test result was available.

Keywords: Bacteraemia; GeneXpert; MRSA; Xpert MRSA/SA BC.