As shown in Fig. 3, morphological changes of E. coli treated with
streptomycin were different from E. coli treated with stems essential
oil. Unlike EO-treated cells which remained almost the same
size, cells incubated with streptomycin compacted and became
shorter with obvious membrane shriveling (Klainer and Russell,
1974). Previous studies have shown that streptomycin may kill
microbes by indirect consequences of ribosomal block which could inhibit the synthesis of protein and ultimately lead to cell death
(Cameron et al., 2014; Raut and Karuppayil, 2014).