Table 1.
Reports of reduced susceptibility to β-lactams amongst group A Streptococcus isolates and the associated amino acid substitutions identified.
| Country (study period) |
Sample source | Number OR Rates | β-lactam antibiotics | Antibiotic resistance test | MIC | Breakpoint standards | Mutations identified | References | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PBP2x | PBP2a | PBP2b | PBP1a | PBP1b | ||||||||
| Mexico 2001 |
Pharyngotonsillitis | 10(5%) | Penicillin G | E-test | 0.25–0.75 μg/ml | NCCLS | — | — | — | — | — | (Amábile-Cuevas et al., 2001) |
| India 2002-2003 |
Acute pharyngotonsillitis | 7(20.6%) | Penicillin | E-test | 0.19-0.25μg/ml | CLSI | — | — | — | — | — | (Capoor et al., 2006) |
| Japan 2006-2008 |
Pharyngitis | 2/93 | Penicillin G | Broth microdilution | >2.0μg/ml | CLSI 2007 | — | — | — | — | — | (Ogawa et al., 2011) |
| India 2016-2017 |
Upper respiratory tract infections | 4(8%), 2(4.2%), 2(5.3%) |
Ampicillin cefotaxime ceftriaxone |
MALDI-TOF Mass Spectrometry (VITEK MS, bioMerieux) | MIC, 0.12-8μg/ml | CLSI | — | — | — | — | — | (Berwal et al., 2018) |
| Australia 2020 |
— | 4/9667 | NC | NC | NC | NC | STMK to SAMK STMK to STIK |
— | — | — | — | (Hayes et al., 2020a) |
| USA 2017-2018 |
Blood and wound isolates | 2/282 | ampicillin & cefotaxime | Broth Microdilution & E-test | Ampicillin 8-fold higher, cefotaxime 3-fold higher | CLSI | T553K substitution | — | — | — | — | (Vannice et al., 2020) |
| USA 2020 |
Mouse Model of Necrotizing Myositis | — | — | — | — | — | Pro601Leu amino acid replacement in PBP2X | — | — | — | — | (Olsen et al., 2020) |
| Iceland 1995-2006 |
— | emm12 strains, 332/1575 | A 2-fold increased penicillin G and ampicillin MIC | Disk diffusion method | — | CLSI, EUCAST | Met593Thr Ile502Val Pro676Ser Lys708Glu |
— | — | — | — | (Southon et al., 2020) |
| Japan 2015-2016 |
Skin, Pus, Tonsil | 3 | — | Agar dilution method | — | CLSI | M593T, A397V | T459A | — | — | — | (Ikeda et al., 2021) |
| 2022 | — | — | — | — | — | Identified 464 pbp2x alleles | 564 pbp2a alleles | — | 389 pbp1a alleles | 427 pbp1b alleles | (Beres et al., 2022) | |
| USA 2015-2021 |
— | 55/13727 | None isolates exhibited nonsusceptibility to b-lactams | — | — | — | emm43.4/PBP2x-T553K variant, two isolates ampicillin MIC 0.25 mg/ml, 129/340 (37.9%) of isolates with elevated β-lactam MICs | — | — | — | — | (Chochua et al., 2022) |
| USA 2022 |
An isogenic mutant strain was generated and virulence assessed in a mouse model of necrotizing myositis | — | — | — | — | — | Strains with the chimeric SDSE-like PBP2X had reduced susceptibility in vitro to nine β-lactam antibiotics | — | — | — | — | (Olsen et al., 2022) |
NCCLS (National Committee for Clinical Laboratory Standards) is the predecessor of Clinical and Laboratory Standards Institute (CLSI) ; WGS, Whole-genome sequencing; MALDI-TOF, Matrix Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry; —, No data OR No clear.