Evaluation of Neisseria gonorrhoeae Isolates Susceptibility to Tetracycline Antibiotics from 9 Provinces in China Since 2020

Figures & data

Table 1 Primers Implemented for PCR Assay and Target Mutations

Target	Primer Name	Primer Sequence
rpsJ	rpsJ_F	5’-GCCAAACCGGGTACTATCAACTCCT-3’
	rpsJ_R	5’-CCGATTTCACCGACCGCACTGT-3’
mtrR	mtrR_F	5’-AACAGGCATTCTTATTTCAG-3’
	mtrR_R	5’-TTAGAAGAATGCTTTGTGTC-3’
porB1b	porB1b_F	5’-CAAGAAGACCTCGGCAA-3’
	porB1b_R	5’-CCGACAACCACTTGGT-3’
tetM_A	tetM_A_F	5’-CTTCCCAACGGAAGCGGTGAT-3’
	tetM_A_R	5’-GGTCCGTCTGAACTTTGCGG-3’
tetM_D	tetM_A_F	5’-CTCCCTAATGGAAGCGGTGC-3’
	tetM_A_R	5’-GGTCAGTCTGAACTTTGCGG-3’
23S rRNA	23SrRNA_F	5’- ACGAATGGCGTAACGATGGCCACA-3’
	23SrRNA_R	5’-TTCGTCCACTCCGGTCCTCTCGTA-3’

Table 2 Antimicrobial Susceptibility Results of 412 N. gonorrhoeae Isolates (Number of Strains Were Indicated in Parentheses)

Antimicrobial	MIC Range (mg/L)	Mode (mg/L)	MIC50 (mg/L)	MIC90 (mg/L)
Ceftriaxone	≤0.008-≥1	0.06 (139)	0.06 (139)	0.25 (20)
Azithromycin	≤0.03-≥8	0.25 (180)	0.25 (180)	1 (65)
Tetracycline	≤0.5–128	2 (186)	4 (148)	64 (59)
Minocycline	≤0.25–64	1 (141)	1 (141)	64 (45)
Tigecycline	0.03–1	0.25 (206)	0.25 (206)	0.5 (120)
Eravacycline	0.06–0.5	0.25 (244)	0.25 (244)	0.5 (48)
Omadacycline	0.5–8	4 (267)	4 (267)	4 (267)

Figure 1 Correlation between MICs of four tetracycline antibiotics and tetracycline, ceftriaxone or azithromycin. Each symbol with specific numbers and colors represents one or multiple isolates. MIC values were log-transformed (log2) before calculating the regression line. (A–D) Correlation between MICs of minocycline, tigecycline, eravacycline, omadacycline and ceftriaxone. (E–H) Correlation between MICs of minocycline, tigecycline, eravacycline, omadacycline and azithromycin. (I–L) Correlation between MICs of minocycline, tigecycline, eravacycline, omadacycline and tetracycline.

Table 3 Presence of Resistance Determinants in N. gonorrhoeae Strains Displaying High Tigecycline MICs or Low Tigecycline MICs

Molecular Markers	MIC≤0.25mg/L	MIC>0.25mg/L	P
porB1A	11	0	0.013
porB1B	23	37	<0.001
GA120KD	20	36	0.153
A121D	16	33	0.086
rpsJ V57M	36	36	1
tetM	11	27	<0.001
tetM_A	1	3	1
tetM_D	10	24	1
mtrR	30	31	1
A39T	7	6	1
G45D	8	5	0.537
−35ΔA	16	26	0.02
23S rRNA	1	5	0.207
C2611T	1	4	0.364
A2059G	0	1	1

Abbreviations: tetM_A, tetM American type; tetM_D, tetM Dutch type.