Case History:
A 3-day-old infant female was transferred to the neonatal intensive care unit (NICU) with a fever. Since birth, the baby was placed on pumped breast milk but is now refusing milk. At presentation, the baby is demonstrating abnormal rapid breathing of > 20 breaths/ minute and rapid heart rate of > 100 beats/ minute. On examination, there is redness and swelling in the umbilical cord stump.
A systemic infection is being considered and a 2 mL blood sample was collected from the infant, inoculated equally into paediatric blood culture bottles (Figure 1) and sent immediately to the clinical microbiology laboratory for loading onto a BACTEC blood culture analyser (Figure 2).
Figure 1. BACTEC blood culture bottles used in the investigation
Figure 2. BACTEC blood culture analyser (opened)
After 16 hours of incubation the blood culture analyser flagged positive and a Gram stain from the bottle revealed a Gram positive coccus was present. On the day of the infant’s admission, the NICU appeared to be free from MRSA however three healthcare workers (H1, H2, H3) and two other infants (F1, F2) later tested positive for MRSA carriage. Whole genome sequencing (WGS) of all MRSA isolates was carried out in order to determine the epidemiological relation among isolates and if there is an outbreak present in the NICU. Your work on this practical will assist with the diagnosis and treatment of the infant and determining the possibility of cross-infection in NICU.