PMC3929008_01
Discharging sinus of chronic osteomyelitis
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F1
The patients was initially fine for two weeks after that he suffered from persistent pain over affected region and six months later a sinus tract developed along with purulent discharge. [Figure 1] The patient received various combinations of antimicrobials (mainly second and third generation cephalosporins) to control the disease.
Blood agar plate showing (a) small colony variant (b) normal variant of Staphylococcus aureus
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F2
After 48 hours of incubation non-pigmented small 0.1 mm diameter non haemolytic colonies grew on BA plate. [Figure 2] MA plate showed no growth. Subculture from this large colony revealed yellow pigmented normal Staphylococcal colony. [Figure 2b] These large colonies were catalase, coagulase (slide and tube) tests positive and oxidase negative.
Antibiotic susceptibility test result of small colony variant of S. aureus
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F3
Antibiotic susceptibility test result showed the isolated strain was only susceptible to vancomycin and resistant to oxacillin, azithromycin, co-trimoxazole, and cefpodoxime. [Figure 3] A lawn culture was put on NA plate along with 20 ug and 40 ug menadione impregnated discs over it.