Using Culture-Enriched Phenotypic Metagenomics for Targeted High-Throughput Monitoring of the Clinically Important Fraction of the β‑Lactam Resistome

High bacterial community diversity and complexity greatly challenge the cost-efficient monitoring of clinically prevalent antibiotic-resistant bacteria, which are usually present as rare and important populations involved in the environmental dissemination of clinical resistance. Here, we introduce culture-enriched phenotypic metagenomics that integrates culture enrichment, phenotypic screening, and metagenomic analyses as an emerging standardized methodology for targeted resistome monitoring and apply it to decipher the extended-spectrum β-lactam resistome in a municipal wastewater treatment plant (WWTP) and its receiving river. The results showed that clinically prevalent carbapenemase genes (e.g., the NDM and KPC families) and extended-spectrum β-lactamase genes (e.g., the CTX-M, TEM, and OXA families) were prevalent in the WWTP and showed prominent potential in horizontal dissemination. Strikingly, carbapenem and polymyxin resistance genes co-occurred in the highly virulent nosocomial pathogens Enterobacter kobei and Citrobacter freundii. Overall, this study exemplifies phenotypic metagenomics for high-throughput surveillance of a targeted clinically important fraction of antibiotic resistomes and substantially expands current knowledge on extended-spectrum β-lactam resistance in WWTPs

Using Culture-Enriched Phenotypic Metagenomics for Targeted High-Throughput Monitoring of the Clinically Important Fraction of the β‑Lactam Resistome

High bacterial community diversity and complexity greatly challenge the cost-efficient monitoring of clinically prevalent antibiotic-resistant bacteria, which are usually present as rare and important populations involved in the environmental dissemination of clinical resistance. Here, we introduce culture-enriched phenotypic metagenomics that integrates culture enrichment, phenotypic screening, and metagenomic analyses as an emerging standardized methodology for targeted resistome monitoring and apply it to decipher the extended-spectrum β-lactam resistome in a municipal wastewater treatment plant (WWTP) and its receiving river. The results showed that clinically prevalent carbapenemase genes (e.g., the NDM and KPC families) and extended-spectrum β-lactamase genes (e.g., the CTX-M, TEM, and OXA families) were prevalent in the WWTP and showed prominent potential in horizontal dissemination. Strikingly, carbapenem and polymyxin resistance genes co-occurred in the highly virulent nosocomial pathogens Enterobacter kobei and Citrobacter freundii. Overall, this study exemplifies phenotypic metagenomics for high-throughput surveillance of a targeted clinically important fraction of antibiotic resistomes and substantially expands current knowledge on extended-spectrum β-lactam resistance in WWTPs

The steady-state power, and the latency and amplitude of N1 and P2 (± SD) at different stimulus types (S1–S3). Right columns report ANOVA results.

<p>The steady-state power, and the latency and amplitude of N1 and P2 (± SD) at different stimulus types (S1–S3). Right columns report ANOVA results.</p

A Divergent Synthesis of γ-Iminolactones, Dihydroquinolin-2-ones, and γ-Lactames from β-Hydroxymethylcyclopropanylamides

γ-Iminolactones 2, dihydroquinolin-2-ones 3, and γ-lactames 4 have been synthesized starting from β-hydroxymethylcyclopropanylamides 1, mediated by SnCl4/NaI/NEt3, BF3·OEt2, and TiCl4/NEt3. The corresponding products 2, 3, and 4 were produced, respectively, in high to excellent yields

A Divergent Synthesis of γ-Iminolactones, Dihydroquinolin-2-ones, and γ-Lactames from β-Hydroxymethylcyclopropanylamides

γ-Iminolactones 2, dihydroquinolin-2-ones 3, and γ-lactames 4 have been synthesized starting from β-hydroxymethylcyclopropanylamides 1, mediated by SnCl4/NaI/NEt3, BF3·OEt2, and TiCl4/NEt3. The corresponding products 2, 3, and 4 were produced, respectively, in high to excellent yields

Amplitudes of transient responses and steady-state responses at different stimulus intensities and ANOVA results.

<p>Amplitudes of transient responses and steady-state responses at different stimulus intensities and ANOVA results.</p

One-Step Synthesis of the Tricyclic Core of Martinellic Acid from 2-(Cyanomethyl)-3-oxo-<i>N</i>-arylbutanamides

A SnCl4·5H2O-mediated facile and efficient one-step synthesis of the tricyclic core of martinellic acid from readily available 2-(cyanomethyl)-3-oxo-N-arylbutanamides was developed and a mechanism involving consecutive hydrolysis of a cyano group and a double annulation process is proposed

Correlations of power between transient responses and steady-state responses.

<p>No significant correlation was observed when examining the relationship between N1 power and 40-Hz steady-state power in S2 (left panel; R = −0.08, P = 0.74), as well as between N1 power and 60-Hz steady-state power in S3 (middle panel; R = −0.01, P = 0.97). In contrast, significant correlation was observed when examining the relationship between 40-Hz steady-state power in S2 and 60-Hz steady-state power in S3 (right panel; R = 0.71, P<0.001). Each green point represents one subject, and the red lines represent the best linear fit.</p

Event-related potentials (ERPs) elicited by transient and periodic auditory stimulation.

<p>Waveforms (recorded at electrode Fz) obtained following transient, 40-Hz periodic, and 60-Hz periodic stimulation are shown in blue, red, and green respectively. The onset of both transient and periodic stimulation elicited clear ERPs consisting a dominant negative peak followed by a positive peak after the use of 1–30 Hz bandpass filter. Even with a low SNR, the middle latency responses (MLRs, i.e., gamma band oscillations) were clearly presented around both 40 Hz and 60 Hz at the early latencies (10–100 ms). Steady-state brain responses, synchronized to 40-Hz and 60-Hz periodic auditory stimulation, were clearly presented using a 35–45 Hz and 55–65 Hz bandpass filter respectively.</p