Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Calvez, Philippe; Breukink, Eefjan; Roper, David I.; Dib, Mélanie; Contreras‐Martel, Carlos; Zapun, André

doi:10.1074/jbc.m116.764696

Cited by 15 publications

(13 citation statements)

References 46 publications

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“…All strains with Thr-445-Ala substitution showed penicillin MIC ≥ 0.25 µg/mL, consistent with a recent work reporting this mutation to reduce PBP binding affinity by 60% and resulting in raised penicillin MIC (>0.25 µg/mL) [26]. Additional mutations beyond the active sites of PBP2b observed in this study had been reported to decrease β-lactams reactivity and is commonly present in strains with penicillin MIC > 0.5 µg/mL [27]. The most common mutations in PBP2x (Thr-338-Ala in STMK motif and Leu-546-Val adjacent to KSG motif) were identified in S. pneumoniae strains exhibiting raised penicillin MICs (2-8 µg/mL), consistent with previous reports associating these mutations with higher-level β-lactam resistance [28][29][30].…”

Section: Discussionsupporting

confidence: 91%

β-Lactam Resistance in Upper Respiratory Tract Pathogens Isolated from a Tertiary Hospital in Malaysia

et al. 2021

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The rise of antimicrobial resistance (AMR) among clinically important bacteria, including respiratory pathogens, is a growing concern for public health worldwide. Common causative bacteria for upper respiratory tract infections (URTIs) include Streptococcus pneumoniae and Haemophilus influenzae, and sometimes Staphylococcus aureus. We assessed the β-lactam resistant trends and mechanisms of 150 URTI strains isolated in a tertiary care hospital in Kuala Lumpur Malaysia. High rates of non-susceptibility to penicillin G (38%), amoxicillin-clavulanate (48%), imipenem (60%), and meropenem (56%) were observed in S. pneumoniae. Frequent mutations at STMK and SRNVP motifs in PBP1a (41%), SSNT motif in PBP2b (32%), and STMK and LKSG motifs in PBP2x (41%) were observed in S. pneumoniae. H. influenzae remained highly susceptible to most β-lactams, except for ampicillin. Approximately half of the ampicillin non-susceptible H. influenzae harboured PBP3 mutations (56%) and only blaTEM was detected in the ampicillin-resistant strains (47%). Methicillin-susceptible S. aureus (MSSA) strains were mostly resistant to penicillin G (92%), with at least two-fold higher median minimum inhibitory concentrations (MIC) for all penicillin antibiotics (except ticarcillin) compared to S. pneumoniae and H. influenzae. Almost all URTI strains (88–100%) were susceptible to cefcapene and flomoxef. Overall, β-lactam antibiotics except penicillins remained largely effective against URTI pathogens in this region.

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Section: Discussionsupporting

confidence: 91%

β-Lactam Resistance in Upper Respiratory Tract Pathogens Isolated from a Tertiary Hospital in Malaysia

et al. 2021

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“…It is notable that mutations in MraY—which are generally last to occur, and never occur alone—might have a compensatory effect. Altered PBPs, while conferring resistance, might be less active transpeptidases than their wild-type counterparts [ 54 ]. For example, the amidotransferase enzyme encoded by murT enables cross-linking of cell wall peptidoglycans by preparing lipid II used by pneumococcal PBPs [ 55 , 56 ].…”

Section: Resultsmentioning

confidence: 99%

Large-scale genomic analysis of antimicrobial resistance in the zoonotic pathogen Streptococcus suis

et al. 2021

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Background Antimicrobial resistance (AMR) is among the gravest threats to human health and food security worldwide. The use of antimicrobials in livestock production can lead to emergence of AMR, which can have direct effects on humans through spread of zoonotic disease. Pigs pose a particular risk as they are a source of zoonotic diseases and receive more antimicrobials than most other livestock. Here we use a large-scale genomic approach to characterise AMR in Streptococcus suis, a commensal found in most pigs, but which can also cause serious disease in both pigs and humans. Results We obtained replicated measures of Minimum Inhibitory Concentration (MIC) for 16 antibiotics, across a panel of 678 isolates, from the major pig-producing regions of the world. For several drugs, there was no natural separation into ‘resistant’ and ‘susceptible’, highlighting the need to treat MIC as a quantitative trait. We found differences in MICs between countries, consistent with their patterns of antimicrobial usage. AMR levels were high even for drugs not used to treat S. suis, with many multidrug-resistant isolates. Similar levels of resistance were found in pigs and humans from regions associated with zoonotic transmission. We next used whole genome sequences for each isolate to identify 43 candidate resistance determinants, 22 of which were novel in S. suis. The presence of these determinants explained most of the variation in MIC. But there were also interesting complications, including epistatic interactions, where known resistance alleles had no effect in some genetic backgrounds. Beta-lactam resistance involved many core genome variants of small effect, appearing in a characteristic order. Conclusions We present a large dataset allowing the analysis of the multiple contributing factors to AMR in S. suis. The high levels of AMR in S. suis that we observe are reflected by antibiotic usage patterns but our results confirm the potential for genomic data to aid in the fight against AMR.

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“…The difference between PBP1b and PBP2x labeling intensity for 7MTz and 7TCO also indicate that protein environment can have a strong effect on bioorthogonal labeling efficiencies. PBP TP active sites are highly structurally homologous, but differences in antibiotic binding between PBPs, along with limited available structural comparisons, suggest that there are subtle differences in active site architecture between PBP isoforms [8,9,12,53–56] . Further structural characterization of PBPs in complex with β‐lactone probes will be necessary to achieve a structure‐based understanding of differences in labeling efficiency.…”

Section: Resultsmentioning

confidence: 99%

Comparison of Bioorthogonal β‐Lactone Activity‐Based Probes for Selective Labeling of Penicillin‐Binding Proteins

et al. 2020

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Penicillin-binding proteins (PBPs) are a family of bacterial enzymes that are key components of cell-wall biosynthesis and the target of β-lactam antibiotics. Most microbial pathogens contain multiple structurally homologous PBP isoforms, making it difficult to target individual PBPs. To study the roles and regulation of specific PBP isoforms, a panel of bioorthogonal βlactone probes was synthesized and compared. Fluorescent labeling confirmed selectivity, and PBPs were selectively enriched from Streptococcus pneumoniae lysates. Comparisons between fluorescent labeling of probes revealed that the accessibility of bioorthogonal reporter molecules to the bound probe in the native protein environment exerts a more significant effect on labeling intensity than the bioorthogonal reaction used, observations that are likely applicable beyond this class of probes or proteins. Selective, bioorthogonal activity-based probes for PBPs will facilitate the activity-based determination of the roles and regulation of specific PBP isoforms, a key gap in knowledge that has yet to be filled.

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Substitutions in PBP2b from β-Lactam-resistant Streptococcus pneumoniae Have Different Effects on Enzymatic Activity and Drug Reactivity

Cited by 15 publications

References 46 publications

β-Lactam Resistance in Upper Respiratory Tract Pathogens Isolated from a Tertiary Hospital in Malaysia

β-Lactam Resistance in Upper Respiratory Tract Pathogens Isolated from a Tertiary Hospital in Malaysia

Large-scale genomic analysis of antimicrobial resistance in the zoonotic pathogen Streptococcus suis

Comparison of Bioorthogonal β‐Lactone Activity‐Based Probes for Selective Labeling of Penicillin‐Binding Proteins

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