Emergence of optrA-Mediated Linezolid Resistance in Enterococcus faecium: A Molecular Investigation in a Tertiary Hospital of Southwest China from 2014–2018

Figures & data

Table 1 Clinical Information and Screening of Linezolid-Resistant Mechanism

Date	Samples	Age/Sex	Wards	Outcome	Antibiotics Usage	Bacterial Type	MLST	LZD MIC (mg/L)	VA MIC (mg/L)	Mechanisms^a
										L22	optrA	poxtA
2014.10.03	Urine	86/male	Geriatrics	Discharge	Penicillin Aminoglycosides Carbapenems	Infection	414^b	4	1
2015.04.20	Blood	66/male	Urology Surgery	Discharge	Aminoglycosides Cephalosporins Carbapenems	Infection	1161	8	0.25		WT
2015.05.22	Urine	70/male	Emergency ward	Transfer	Cephalosporins	Colonization	80^b	4	0.25
2015.06.15	Secretion	69/male	Vasculr Surgery	Discharge	Cephalosporins Carbapenems	Infection	8	8	1			+
2015.07.12	Urine	47/Famale	Urology Surgery	Transfer	Penicillin	Infection	117^b	8	0.25		WT
2015.08.08	Ascites	86/male	Gastrointestinal Surgery	Discharge	Carbapenems	Infection	1850^b	4	0.25
2015.08.18	Urine	74/male	Neurology	Transfer	None	Infection	78^b	4	0.25
2016.08.04	Drainage	78/male	ICU	Discharge	Cephalosporins	Colonization	1160	8	0.25
2016.02.09	Urine	46/Famale	Rehabilitation	Transfer	Cephalosporins	Infection	78^b	8	0.25
2017.01.27	Drainage	70/male	Gastrointestinal Surgery	Discharge	Cephalosporins	Colonization	Unclassified	8	0.25		P
2018.03.09	Urine	78/male	Urology Surgery	Discharge	Cephalosporins	Infection	Unclassified	8	0.25		P
2018.07.20	Bile	51/Famale	Hepatobiliary Surgery	Discharge	Cephalosporins	Colonization	Unclassified	4	0.25	Ser77Thr
2018.08.10	Secretion	61/male	Dermatology	Discharge	Penicillin	Colonization	425	8	0.5		P
2018.10.02	Secretion	74/male	Nephrology	Transfer	None	Colonization	8	16	0.5		P
2018.11.07	Secretion	65/male	Gastrointestinal Surgery	Discharge	Penicillin Cephalosporins Fluoroquinolones	Infection	117^b	8	0.25		EYDNDM	+

Notes: P, T481P; EYDNDM, Lys3Glu, Asn12Tyr, Tyr176Asp, Asp247Asn, Gly393Asp, Ile622Met. ^aNo mutations in genes encoding domain V of 23S rRNA or ribosomal proteins L3/L4 were found. ^bIsolates belonging to CC17 clone.

Abbreviation: ICU, intensive care unit.

Figure 1 Structure of two resistant gene plasmids in E. faecium_7150. (A) Structure of the optrA-carrying plasmid pEF7150-3. (B) Structure of the poxtA-carrying plasmid pEF7150-5. The peripheral circle represents CDS, and arrows indicate the CDSs and their transcription directions. The second and third circle shows GC skew and GC content respectively. The purple square refers to other function gene. The yellow square refers to other resistant gene. The red square refers to linezolid resistant gene. The grey square refers to mobile genetic elements.