Utility of Methicillin-Resistant Staphylococcus aureus Nares Screening in Hospitalized Children with Acute Infectious Disease Syndromes

Abstract

Studies in adults support the use of a negative methicillin-resistant Staphylococcus aureus (MRSA) nares screening (MNS) to help limit empiric anti-MRSA antibiotic therapy. We aimed to evaluate the use of MNS for anti-MRSA antibiotic de-escalation in hospitalized children (<18 years). Records of patients admitted between 1 January 2015 and 31 December 2020 with a presumed infectious diagnosis who were started on anti-MRSA antibiotics, had a PCR-based MNS, and a clinical culture performed were retrospectively reviewed. A total of 95 children were included with a median age (range) of 2 (0–17) years. The top three diagnosis groups were skin and soft tissue infections (n = 38, 40%), toxin-mediated syndromes (n = 17, 17.9%), and osteoarticular infections (n = 14, 14.7%). Nasal MRSA colonization and growth of MRSA in clinical cultures was found in seven patients (7.4%) each. The specificity and the negative predictive value (NPV) of the MNS to predict a clinical MRSA infection were both 95.5%. About half (n = 55, 57.9%) had anti-MRSA antibiotics discontinued in-house. A quarter (n = 14, 25.5%) were de-escalated based on the negative MNS test alone, and another third (n = 21, 38.2%) after negative MNS test and negative culture results became available. A high NPV suggests that MNS may be useful for limiting unnecessary anti-MRSA therapy and thereby a useful antimicrobial stewardship tool for hospitalized children. Prospective studies are needed to further characterize the utility of MNS for specific infectious diagnoses.

Pediatric Utilization of Methicillin-resistant Staphylococcus aureus Nasal Swabs for Antimicrobial Stewardship

“…A study conducted at another children’s hospital in New York also reported a high NPV of 95.5% and a low PPV of 42.9% for all indications combined. 10 Of note, this cohort study utilized PCR-based MNS. PCR-based MNS tests were excluded in our study due to low utilization during the study period as our institution transitioned to preferentially utilizing PCR-based MNS in the last few months of the study period.…”

Utilization of Methicillin-resistant Staphylococcus aureus Nasal Swabs for Antimicrobial Stewardship: What About Hospitalized Children With Osteomyelitis?

“…1 Their key finding of a high negative predictive value (NPV) (95%) of MNS for all combined indications adds to 2 previously and 1 since published studies in children confirming high NPVs (95.5%-100%) for infections that primarily included lower respiratory tract infections (LRTI) and skin and soft tissue infections (SSTI). [2][3][4][5] We applaud Braga for being able to calculate the first-time infection-specific NPVs of MNS in children with LRTIs [95% (n = 46)], SSTIs [96% (n = 24)] and bone and joint infections (BJIs) [91% (n = 22)]. We concur with their conclusions that MNS in children may have a utility beyond LRTIs including SSTIs and BJIs as well as with their call for more data specifically for those 2 latter infections.…”

“…This work represents a subanalysis of our group's endeavor since 2015 to evaluate SNS's utility in hospitalized children, which has been approved by our institutional review board and its results in part previously reported. 3 We included 36 patients with a median age (range) of 8.5 years (0-19). Thirty-two (88.9%) were started on empiric anti-MRSA antibiotics, most on clindamycin (n = 21, 58.3%), vancomycin (n = 8, 22.2%), or both (n = 2, 5.6%).…”

“…1 Their key finding of a high negative predictive value (NPV) (95%) of MNS for all combined indications adds to 2 previously and 1 since published studies in children confirming high NPVs (95.5%–100%) for infections that primarily included lower respiratory tract infections (LRTI) and skin and soft tissue infections (SSTI). 2–5…”

“…This work represents a subanalysis of our group’s endeavor since 2015 to evaluate SNS’s utility in hospitalized children, which has been approved by our institutional review board and its results in part previously reported. 3…”