Ultrastructural cell wall characteristics of clinical gentamycin-resistant Staphylococcus aureus isolates
- PDF / 476,470 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 71 Downloads / 211 Views
ORIGINAL PAPER
Ultrastructural cell wall characteristics of clinical gentamycin-resistant Staphylococcus aureus isolates Kenji Fukutsuji • Sakuo Yamada • Tamotsu Harada
Received: 16 January 2012 / Accepted: 26 March 2012 / Published online: 22 January 2013 Ó The Japanese Society for Clinical Molecular Morphology 2013
Abstract The frequent use of gentamycin (GM) ointment for the treatment of skin infections has led to an increase in the number of GM-resistant clinical isolates of Staphylococcus aureus. We examined the ultrastructural characteristics of 14 clinical strains of S. aureus by transmission electron microscopy. Seven of these isolates were GM-resistant, and seven isolates were GM-sensitive. We found that the cell wall of GM-resistant strains (32.24 ± 5.99 nm) was significantly thicker than that of GM-sensitive strains (19.02 ± 2.72 nm). We genetically characterized these isolates by polymerase chain reaction, targeting the genes for three aminoglycoside-modifying enzymes, aac(60 )-aph(200 ), aph(30 )-III, and ant(40 )-I. All GM-resistant strains tested carried the gene encoding aac(60 )-aph(200 ). However, we were unable to establish a link between a specific gene and cell wall thickening, because one GM-resistant strain was also positive for aph(30 )-III. We also demonstrated that a GM-resistant mutant strain, derived in vitro from a GM-sensitive S. aureus parent strain (209P), also exhibited a thickened cell wall. These results strongly suggest that a thickened cell wall is a common ultrastructural characteristic of GM-resistant S. aureus clinical strains.
K. Fukutsuji (&) T. Harada Department of Otolaryngology, Kawasaki Medical School, 577 Matsusima, Kurasiki, Okayama, Japan e-mail: [email protected] K. Fukutsuji S. Yamada Department of Microbiology, Kawasaki Medical School, Okayama, Japan S. Yamada Department of Clinical Nutrition, Kawasaki University of Medical Welfare, Okayama, Japan
123
Keywords Cell wall Gentamycin Staphylococcus aureus Ultrastructure Antibiotic resistance
Introduction Staphylococcus aureus is the pathogen most commonly associated with bacterial skin infections. In addition, S. aureus is capable of rapidly developing or acquiring multiple antibiotic resistance. Gentamycin (GM) is an antibiotic of the aminoglycoside group, which inhibits protein synthesis by causing misreading of the messenger RNA [1]. The effectiveness of aminoglycoside antibiotics is dependent on the concentration used [2]. Clinically available GM is a mixture of the isomers Cl, Cla, and C2, which have similar properties [3]. Although GM can be administered as an injection, it is often used as ointment for skin infections and for secondary bacterial infections of skin erosions and ulcers. The frequent use of GM ointment for treating skin infections has recently led to an increase in GM-resistant S. aureus strains [4]. Staphylococci resistance to aminoglycoside antibiotics is commonly due to enzymatic modification [5]. Specifically, three types of enzymes account for resistance in clinical
Data Loading...
