Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland: a case report

Table 1 Reported susceptibility data (MIC) of culture (according to EUCAST 2019) as well as corresponding classes of antibiotics and/or target genes

Substance	MIC	Reported phenotype	Antimicrobial/target gene^a	Remarks
Ceftriaxone	0.25 mg/l	resistant	β-Lactam penA, porinB, ponA, bla	0.38: value from CLM Dr Risch Group 0.25: value from IMM (UZH) MIC breakpoint: S ≤ 0.125 mg/l, R > 0.125 mg/l
Penicillin	0.5 mg/l	intermediate	PorinB
Ciprofloxacin	12.0 mg/l	resistant	Fluoroquinolone gyrA and parC	MIC breakpoint: S ≤ 0.03 mg/l, R > 0.06 mg/l
Azithromycin	0.5 mg/l		Macrolide 23S rRNA gene	Azithromycin is always used in conjunction with another effective agent. ECOFF: 1 mg/l
Tetracycline	0.38 mg/l	susceptible	Tetracycline rpsJ, mtrR, penB, tetM-encoding plasmids	MIC breakpoint: S ≤ 0.5 mg/l, R > 1.0 mg/l

Ceftriaxone testing was performed at the CLM Dr Risch Group as well as at the Institute of Medical Microbiology (IMM) of the University of Zurich (UZH) for confirmation. ECOFF is the “epidemiological cutoff value”
^aMore details on target genes are provided in reviews of the literature [11, 12].

ISSN: 1476-0711