| Description |
Antibiotics are not only essential for human health but also for the well-being of plants and animals. However, the use of antibiotics has led to the evolution of antibiotic-resistant bacteria (ARB) in the environment. Antibiotic resistance in bacteria is a serious public health concern. ARBs are not only a predicament in clinical scenarios and daily life but also existing in many other environments. Wastewater treatment plants have been acknowledged as breeding grounds for such bacteria. As part of this research, a kanamycin-resistant bacterium, Chryseobacterium taeanense strain K-2, was isolated from the Central Valley Water Reclamation Facility and chosen as a model organism for the study. The bacterium was Gram negative, 0.5 μm long with coccoid morphology, and belonged to the Flavobacteriaceae family. The doubling time was observed to be ~2 h. Some species of bacteria under this genus have been associated with pathogenicity in human. This is, however, the first report on an antibiotic-resistant strain of Chryseobacterium taeanense and its presence in wastewater can be a serious concern. A lytic bacteriophage infecting Chryseobacterium taeanense strain K-2 was isolated from Central Valley Water Reclamation Facility. The lytic infection was evident from distinct clear plaques of 1-2 mm diameter obtained on top agar plates. According to the TEM analysis, the phage belongs to the Podoviridae family with a short tail, hexagonal head, and a total length of 90-100 nm. The latent and eclipse period of lytic infection were found to be the same (10 min). The burst size was around 18±2 PFUs/infected cell. Significantly short latent period and relatively high burst size indicate the exceptional potential of the lytic phage to regulate even very high populations of the host. The optimal phage-to-host ratio for infection was found to be 100:1, causing 98.7% of host death after 9 h. The lytic phage was also found to infect the host cells within the biofilm. The biofilm disintegration and degradation of the extra-polymeric substance within the matrix of the biofilm was evident after overnight infection with the phage. In conclusion, the lytic phage isolated in the present study can be attributed with significant potential for biocontrol of both biofilm-forming and planktonic forms of antibiotic-resistant bacterium, Chryseobacterium taeanense strain K-2. |
