Riverbank erosion vulnerability assessment and coping strategies: A case study of the riparian communities in the Mekong River Basin in Cambodia

Riverbank erosion is a major hazard for riparian communities in the Mekong River Basin. This study aims to (1) assess the livelihood vulnerability of two communities residing along the Mekong River, namely, Kaoh Soutin (KS) and Ruessei Srok (RS), by using the livelihood vulnerability index framed within the Intergovernmental Panel on Climate Change vulnerability framework (LVI-IPCC) and (2) identify the coping strategies of the communities based on semi-structured interviews. The results show that KS is slightly more vulnerable to riverbank erosion than RS, as indicated by LVI-IPCC values of 0.49 and 0.46 for KS and RS, respectively. RS exhibits high adaptive capacity and low sensitivity, but its exposure level is relatively high. Majority of the respondents in KS (62 %) and RS (93 %) were affected by riverbank erosion. In KS, approximately 48 % of the respondents experienced displacement, and 39 % of them relocated once. Meanwhile, in RS, 81 % of the respondents experienced displacement, with 46 % displaced at least three times. The affected households have coped with riverbank erosion by reducing expenses, diversifying their income sources, seeking support from others, and receiving assistance from local authorities, NGOs, and government interventions. Despite such efforts to mitigate the effects of riverbank erosion, the high level of exposure and external factors, such as high living costs and low profits from agriculture, have weakened the ability of the people in both communities to cope with disasters. Moreover, the social ties among households, especially in KS, have declined, thereby making low-income households highly vulnerable to riverbank erosion.

Induction of Antimicrobial Resistance of Stenotrophomonas maltophilia by Exposure to Nonlethal Levels of Antibiotics

The effects of the sequential subculture in the presence of a driving force on antimicrobial resistance of Stenotrophomonas maltophilia K279a were investigated. Stationary-phase cells were inoculated into the lysogeny broth medium, with and without antibiotic supplementation, and grown until the stationary phase before being subcultured into the same antibiotic-supplemented medium for six consecutive cycles. Thirty colonies from each cycle and treatment condition were selected and their antibiotic susceptibility profiles were determined. The sequential subculture of K279a for a number of cycles reduced susceptibility to diverse classes of antibiotics, including ciprofloxacin, amikacin, gentamicin, ceftazidime, co-trimoxazole, and chloramphenicol, regardless of the antibiotic used. Supplementation with antibiotics that is, ampicillin, kanamycin, ciprofloxacin, and ceftazidime, at sublethal concentrations significantly accelerated the development rate of strains that reduced susceptibility to other antibiotics. The patterns of reduced susceptibility were different depending on the antibiotic used for supplementation. Thus, without gene transfer, antibiotic-resistant strains of S. maltophilia can readily develop, especially after antibiotic treatments. Whole-genome sequence analysis of the selected antibiotic-resistant mutants identified gene mutations that might be responsible for antimicrobial resistance of S. maltophilia.