Scanning electron microscopy and antibiotic sensitivity of the actinobacterium, Kocuria sediminis DDK6

Abstract

In the present work, the cellular arrangements and shape of Kocuria sediminis DDK6 which was isolated from a diesel-oil contaminated soil, were investigated using scanning electron microscope (SEM). Additionally, the intrinsic antibiotic resistance of theDDK6 to 10 different antibiotics was also assessed using disc diffusion antibiotic sensitivity testing. The results obtained from SEM indicated that cells of the strain DDK6 were arranged in pairs, tetrads, packets and grape-like clusters. Typical spherical-shaped cells with a diameter between 0.7 -0.9 um, were observed. The cell surface appeared relatively smooth in texture. Additionally, circumferential rings with different spatial planes were observed in cells with various arrangements, indicating different planes of divisions. Results of intrinsic antibiotic resistance revealed that DDK6 strain was sensitive to all antibiotic tested at the applied concentration, except for the nitrofurantoin (F 300 µg). The diameter of the inhibition zone ranged between 0.85-1.3 cm highlighting variations in susceptibility levels to the antibiotic tested. In conclusion, DDK6 could adjust the position of the cell division site to cope with the habitat in which it lives, and resistance to the nitrofurantoin could be used as a rapid identification of Kocuria spp, in addition, to many other phenotypic traits.