Journal: Antimicrobial Agents and Chemotherapy

Article Title: Differences in β-lactamase activity and carbapenem resistance among the Bacillus cereus group

doi: 10.1128/aac.01302-25

Figure Lengend Snippet: Phylogenetic tree of 48 clinical isolates from the Bacillus cereus group and the reference strain B. cereus ATCC 14579, with associated antimicrobial susceptibility, mCIM results, enzyme activity, and β-lactamase gene profiles. A phylogenetic tree of 48 NR isolates of Bacillus cereus group combined with the reference strain B. cereus ATCC 14579 was constructed using Mashtree . All isolates were classified into three species: Bacillus mosaicus , Bacillus luti , and Bacillus cereus sensu stricto ( s.s .). A total of 28 distinct sequence types (STs) were identified. B. cereus s.s . isolates belonged to panC group IV, B. luti belonged to group V, and B. mosaicus belonged to groups II or III. Minimum inhibitory concentrations (MICs) of ampicillin and meropenem were represented using a color gradient from white (low MICs) to red (high MICs). Positive results in the mCIM are indicated by red boxes. The enzyme activity categories are shown with colored boxes; red indicates constitutive activity, green indicates inducible activity, and blue indicates a silent phenotype. The genetic structures around bla1 and BcII are shown based on the classifications shown in , respectively. Abbreviation: mCIM, modified carbapenem inactivation method.

Article Snippet: Although NR5374 and NR5375 showed high levels of meropenem activity, their BcII expression levels (NR5374: 1.69, and NR5375: 0.91) were comparable to those of the three silent isolates with minimal meropenem activity (NR5408:0.93, NR5415:1.38, and ATCC 14579:1.00).

Techniques: Activity Assay, Construct, Sequencing, Modification

Journal: Antimicrobial Agents and Chemotherapy

Article Title: Differences in β-lactamase activity and carbapenem resistance among the Bacillus cereus group

doi: 10.1128/aac.01302-25

Figure Lengend Snippet: Enzyme activity against penicillin G ( a ) and meropenem ( b ). Boxplots were generated using the statistical software R version 4.3.2 and ggplot2 to show the distribution of the enzyme activity. The box represents the interquartile range (IQR), the horizontal line indicates the median, and the whiskers extend to 1.5 × IQR. Outliers are plotted as individual points. The enzyme activity was plotted for each bacterial isolate. Data points obtained with (+) and without (–) cefoxitin (CFX) induction are connected by a line to illustrate inducibility. The color of each dot represents the mode of penicillin G enzyme activity: red indicates the constitutive type, green the inducible type, and blue the silent type. The enzyme activity values (U/mg) are shown on a logarithmic scale. The β-lactamase activity values are the mean of three measures, with standard deviations within 10%.

Article Snippet: Although NR5374 and NR5375 showed high levels of meropenem activity, their BcII expression levels (NR5374: 1.69, and NR5375: 0.91) were comparable to those of the three silent isolates with minimal meropenem activity (NR5408:0.93, NR5415:1.38, and ATCC 14579:1.00).

Techniques: Activity Assay, Generated, Software

Journal: Antimicrobial Agents and Chemotherapy

Article Title: Differences in β-lactamase activity and carbapenem resistance among the Bacillus cereus group

doi: 10.1128/aac.01302-25

Figure Lengend Snippet: D-shaped zone of inhibition in inducible B. mosaicus . D-shaped zone of inhibition around the meropenem (M) disk adjacent to the cefoxitin (C) disk. Disks containing meropenem (10 µg) and cefoxitin (10 µg) were placed 20 mm apart on a Mueller-Hinton agar that had been inoculated overnight with B. mosaicus NR5416 in The induction group. The double-disk test was conducted in triplicate, and each replicate showed a similar D-shaped zone of inhibition.

Article Snippet: Although NR5374 and NR5375 showed high levels of meropenem activity, their BcII expression levels (NR5374: 1.69, and NR5375: 0.91) were comparable to those of the three silent isolates with minimal meropenem activity (NR5408:0.93, NR5415:1.38, and ATCC 14579:1.00).

Techniques: Inhibition