Antibiotic stress alters lysogeny-lysis dynamics and drives phage-mediated transfer of antibiotic resistance genes in the activated sludge process.

The spread of antibiotic resistance genes (ARGs) in wastewater treatment systems poses a significant public health concern, yet the role of bacteriophages (phages), particularly temperate phages, in mediating horizontal gene transfer (HGT) of ARGs under antibiotic stress remains poorly understood. This study investigated the effects of escalating ciprofloxacin (CIP; 0-200 μg/L)-selected as a representative antibiotic due to its frequent occurrence and persistence in wastewater-on phage lysogeny-lysis dynamics and phage-mediated ARG transfer in a laboratory-scale activated sludge reactor. Integrating metaviromic and metagenomic analysis revealed that the phage-mediated ARG-HGT events mainly occurred at the highest CIP concentration stage (200 μg/L), indicating that high-level antibiotic stress is essential for triggering significant ARG transfer.

Significant impact of bleaching treatment on phage-host interaction dynamics in a full-scale wastewater treatment plant.

The temporal dynamics of phage-host interactions within full-scale biological wastewater treatment (BWT) plants remain inadequately characterized. Here, we provide an in-depth investigation of viral and bacterial dynamics over a nine-year period in an activated sludge BWT plant, where bleach addition was applied to control sludge foaming. By conducting bioinformatic analyses on 98 metagenomic time-series samples, we reconstructed 3,486 bacterial genomes and 2,435 complete or near-complete viral genomes, which were classified into 361 bacterial and 889 viral clusters, respectively.

Expression and biological activity of lytic proteins HolST-3 and LysST-3 of Salmonella phage ST-3.

Salmonella infection is a major public health concern. Several strategies for Salmonella infection prevention and control are currently available including vaccines and antibiotics. However, vaccines are expensive and inefficient, and the use of antibiotics can lead to antibiotic resistance.

Isolation and characterization of SGF3, a novel Microviridae phage infecting Shigella flexneri.

In the context of widespread bacterial contamination and the endless emergence of antibiotic-resistant bacteria, more effective ways to control pathogen infection are urgently needed. Phages become potential bactericidal agents due to their bactericidal specificity and not easy resistance to bacteria. But an important factor limiting its development is the lack of phage species.

Genomic characterization of a novel virulent phage infecting Shigella fiexneri and isolated from sewage.

Shigella fiexneri phage SGF2 is a novel lytic phage isolated from a sewage sample. Morphological characterization indicates that phage SGF2 is a member of the Podoviridae family, producing virions with an isometric head (82.6 ± 8 nm diameter) and a short non-contractile tail (length 52 ± 8 nm).

Characterization and coagulation-flocculation performance of a composite flocculant in high-turbidity drinking water treatment.

Klebsiella variicola B16, a microbial bioflocculant (MBF-B16)-producing bacteria, was isolated and identified by its 16S rRNA sequence, biochemical properties, and physiological characteristics. The effects of culture conditions on MBF-B16 production, including carbon source, nitrogen source, C/N ratio, initial pH, and culture temperature, were investigated in this study. Results showed that 6.