Screening for ß-lactam resistance by penicillin G in the Streptococcus anginosus group challenged by rare strains with altered PBPs.
J Antimicrob Chemother
; 77(7): 1847-1850, 2022 06 29.
Article
en En
| MEDLINE
| ID: mdl-35466361
ABSTRACT
BACKGROUND:
Streptococcus anginosus group (SAG) strains are common pathogens causing abscesses and bacteraemia. They are generally susceptible to ß-lactams, which constitute first-line treatment. EUCAST recommends testing penicillin G susceptibility to screen for ß-lactam resistance. Isolates categorized as susceptible (negative screening) can be reported as susceptible to aminopenicillins and third-generation cephalosporins.OBJECTIVES:
To assess the reliability of penicillin G resistance screening in predicting ß-lactam resistance in SAG blood culture isolates, and to investigate isolates for which this test would be unreliable.METHODS:
We determined the susceptibility to penicillin G, amoxicillin and ceftriaxone of 90 SAG blood culture isolates, all with negative penicillin G resistance screening. ß-Lactam-resistant strains were sequenced and compared with susceptible reference SAG strains.RESULTS:
We detected two isolates displaying ß-lactam resistance, especially to third-generation cephalosporins, despite negative screening for penicillin G resistance. For these isolates, amino acid substitutions were identified next to the essential PBP motifs SxxK, SxN and/or KS/TGS/T. Changes in these motifs have been previously linked to ß-lactam resistance in Streptococcus pneumoniae.CONCLUSIONS:
Our study suggests that aminopenicillin and third-generation cephalosporin susceptibility should be determined for SAG strains in the event of severe infection as screening for penicillin G resistance might not be sufficient to detect resistance mechanisms that predominantly affect cephalosporins. The PBP sequencing of resistant SAG strains allowed us to detect amino acid changes potentially linked to ß-lactam resistance.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Resistencia betalactámica
/
Streptococcus anginosus
Tipo de estudio:
Diagnostic_studies
/
Prognostic_studies
/
Screening_studies
Idioma:
En
Revista:
J Antimicrob Chemother
Año:
2022
Tipo del documento:
Article
País de afiliación:
Francia