MICROSCOPY Vol.45▶No.4 2010
■Feature Articles: Up-to-date Research on Microorganism

Ultrastructural Analysis of Macrolide–Resistant Staphylococci Isolated from Patients with Transmisssion Electron Microspopy

Yukiyoshi Hyo, Sakuo Yamada and Tamotsu Harada

Abstract: Fourteen-membered-ring macrolides have been used widely against bacterial infection. These days, in addition to their well-established role as antibiotics, macrolides have an anti-inflammatory effect, in addition to their antibacterial effect, and are widely used at low dosages for long-term therapy for chronic inflammatory disease such as diffuse pan-bronchiolitis and chronic sinusitis. A macrolide-resistant coagulase-negative staphylococcal strain was obtained from the maxillary sinus of a patient with chronic sinusitis, who failed long-term macrolide therapy. Morphological observation demonstrated that this macrolide-resistant Staphylococcus capitis s strain had a thicker cell wall than macrolide-sensitive S. capitis strains. Moreover, macrolide-resistant four S. epidermidis strains isolated from patients also had thicker cell wall than macrolide-sensitive strain. On the other hand,  the strain was not carrying any other than the four genes that are known mainly to encode for macrolide resistance in S. aureus, and it was not recognized in macrolide-resistant S. epidermidis strains that  there was clear relationships between the genes encoding macrolide-resistance and  the  cell wall-thickness. Therefore, it was suggested that the strain had an unknown macrolide-resistance mechanism that might be related to cell wall thickening.

Key words: macrolide, staphylococci, ultrastracture,antibiotics-resistance