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Aim: This study assessed the Streptococcus pneumoniae colonisation rate and susceptibility to antibiotics among preschool children in rural Vietnam. Method: Nasopharyngeal samples were collected from 546 preschool children aged 6–59 months living in 460 households in the rural BaVi District of Hanoi and their main caregivers completed questionnaires. The samples were cultured, and the Streptococcus pneumoniae colonisation rate and antibiotic susceptibility were investigated. Resistance data from this 2014 study were compared with studies in 1999 and 2007, to identify 15‐year trends, together with clinical isolates from a national surveillance system of 16 Vietnamese hospital laboratories established in 2013. Results: We found that 221/546 (40%) of the cultures were positive for Streptococcus pneumoniae. The susceptibility rates were trimethoprim‐sulphamethoxazole (5%), erythromycin (8%), ciprofloxacin (12%), benzyl‐penicillin (35%), tetracycline (49%), cefotaxime (55%), moxifloxacin (99%) and vancomycin (99%). All the susceptibility rates were lower in 2014 than 1999 and 2007, except tetracycline. Multi‐drug resistance was 80% in 2014, compared to 60% in 2007 and 31% in 1999. Antibiotics was reported used by 191 (35%) within one month, mainly cephalosporins 86 (45%), amoxycillin/ampicillin 69 (36%) and macrolides 30 (16%). Conclusion: Streptococcus pneumoniae showed remarkable high resistance to commonly used antibiotics, including cephalosporins. Multi‐drug resistance rose from 31% to 80% during the 15‐year study period. [ABSTRACT FROM AUTHOR]

Plasticity in salt tolerance can be crucial for successful biological invasions of novel habitats by marine gastropods. The intertidal snail Batillaria attramentaria, which is native to East Asia but invaded the western shores of North America from Japan 80 years ago, provides an opportunity to examine how environmental salinity may shape behavioral and morphological traits. In this study, we compared the movement distance of four B. attramentaria populations from native (Korea and Japan) and introduced (United States) habitats under various salinity levels (13, 23, 33, and 43 PSU) during 30 days of exposure in the lab. We sequenced a partial mitochondrial CO1 gene to infer phylogenetic relationships among populations and confirmed two divergent mitochondrial lineages constituting our sample sets. Using a statistical model‐selection approach, we investigated the effects of geographic distribution and genetic composition on locomotor performance in response to salt stress. Snails exposed to acute low salinity (13 PSU) reduced their locomotion and were unable to perform at their normal level (the moving pace of snails exposed to 33 PSU). We did not detect any meaningful differences in locomotor response to salt stress between the two genetic lineages or between the native snails (Japan vs. Korea populations), but we found significant locomotor differences between the native and introduced groups (Japan or Korea vs. the United States). We suggest that the greater magnitude of tidal salinity fluctuation at the US location may have influenced locomotor responses to salt stress in introduced snails. [ABSTRACT FROM AUTHOR]