Table 2.

Antimicrobial Treatment Changes in Response to RMg Results

Treatment Change	n (%)
Indication for RMg testing	N = 128
CA LRTI	30 (23)
HA LRTI	80 (63)
Start of episode	37 (29)
During episode	43 (34)
Other*	18 (14)
Antibiotic prescribing†	n = 110‡
Receiving antibiotics start of RMg test day	89 (81)
Receiving antibiotics end of RMg test day	98 (89)
Deescalation, antibiotics stopped with:
RMg§	29
Same day	7 (24)
Next dayǁ	22 (76)
Meropenem	15
Piperacillin–tazobactam	6
Linezolid	5
Other	3
Escalation, antibiotics started with:
RMg¶	n = 24
Same day	21 (87)
Next day**	3 (13)
Meropenem	10
Linezolid	4
Other	10

Definition of abbreviations: CA = community-acquired; HA = hospital-acquired; LRTI = lower respiratory tract infection; RMg = respiratory metagenomics.

^*Includes where the focus of infection was uncertain at time of testing, to exclude respiratory infection preimmunomodulation or after completing therapy for LRTI.

^† Fifteen patients had antibiotics started or stopped for reasons not linked with the RMg result.

^‡ Excludes samples failed at quality control (n = 15) or sent from nonpilot critical care areas (n = 3).

^§ Antifungals were stopped in 3 patients in response to RMg results.

^ǁ Two patients had antibiotics stopped on second day after testing.

^¶ Antifungals were started for 5 patients in response to RMg results.

^**Three patients had antibiotics started in response to RMg results 2 days after receipt of the result.