- Email: [email protected]
A novel 23S rRNA mutation in Propionibacterium acnes confers resistance to 14-membered macrolides
Journal of Global Antimicrobial Resistance 6 (2016) 160–161
Contents lists available at ScienceDirect
Journal of Global Antimicrobial Resistance journal homepage: www.elsevier.com/locate/jgar
Letter to the Editor A novel 23S rRNA mutation in Propionibacterium acnes confers resistance to 14-membered macrolides Sir, Propionibacterium acnes is a major pathogenic factor of acne vulgaris. Antimicrobial agents are used in treatment targeting this bacterium; traditionally, oral and topical macrolides have frequently been used for this purpose. As a result, macrolide-resistant P. acnes exhibiting cross-resistance to clindamycin has been widely disseminated worldwide [1]. Macrolide/clindamycin-resistant P. acnes has been categorised into four groups according to differences in the resistance factors and antibiotic susceptibility [2]. Strains belonging to three of the four groups harbour a mutation at positions 2057, 2058 and 2059, respectively, related to domain V, of 23S rRNA, and strains belonging to these groups are the most predominant in macrolideresistant P. acnes. Susceptibility to macrolides and clindamycin differs according to the point mutation that the strains harbour. Strains belonging to the fourth group harbour the erm(X) gene, which is responsible for dimethylation of 23S rRNA [2]. Although dissemination of clinical P. acnes isolates harbouring the erm(X) gene is rare, these strains exhibit the highest level of resistance to macrolides and clindamycin [2]. In this study, novel mechanisms of resistance to macrolides in P. acnes isolated from patients with acne vulgaris since 2009 in Japan were investigated. During this period, a macrolide-resistant strain was found that had no known resistance determinants. Here we show that a novel 23S rRNA mutation in P. acnes confers resistance to 14-membered macrolides. Sixteen macrolide-resistant P. acnes strains isolated at Tokyo Woman’s Medical University Hospital (Tokyo, Japan) were used in this study. Among them, a strain (68b) was observed that exhibited high-level resistance to clarithromycin [minimum inhibitory concentration (MIC) 256 mg/mL] but was susceptible to spiramycin (MIC = 1 mg/mL) and clindamycin (MIC = 0.25 mg/ mL) [3]. Strain 68b was identified as type II and K1 for recA typing and single-locus sequence type, respectively. According to an interview sheet, the patient in whom this strain was detected was diagnosed with moderate acne vulgaris and did not use any antibiotics. There are only a few reports describing mobile genetic elements, such as plasmids and transposons, in P. acnes, and dissemination of the erm(X) derived from Corynebacterium is rare. In addition, the susceptibility pattern of strain 68b to macrolides and clindamycin was similar to that of strains harbouring a mutation at positions 2057 2059 in the 23S rRNA gene. Therefore, we presumed that strain 68b had a mutation in the 23S rRNA gene. Sequencing analyses of the strain were performed for positions 748 and 752 at domain II, which is located adjacent to domain V,
and for position 2610 at domain V of 23S rRNA. Simultaneously, the rplD and rplV genes for ribosomal proteins L4 and L22, respectively, were also sequenced. The results of the analyses showed that strain 68b harboured a novel cytosine to guanine mutation at position 2611 (2611C!G) in the 23S rRNA gene (Fig. 1). Of the other 15 macrolide-resistant strains, erm(X) was detected from 1 strain, and the other strains harboured the 2058A!G or 2059A!G mutation in the 23S rRNA gene [3]. Compared with the other resistant strains, the strain harbouring 2611C!G in the 23S rRNA gene exhibited susceptibility to spiramycin (a 16-membered macrolide) and clindamycin (a lincosamide), similar to the susceptible strains (Fig. 1). The sequence was verified by BLAST analysis against the GenBank database to check whether the 2611C!G mutation had already been reported; the mutation has not been deposited in the GenBank database. None of the strains tested in this study exhibited multiple resistance factors. In addition, none of the strains harboured mutations at domain II and position G2057 of 23S rRNA, or in the rplD and rplV genes. Mutation at position 2611 in the 23S rRNA gene has been reported in Escherichia coli and Chlamydomonas [4]. Furthermore, the mutation has also been detected in Streptococcus pneumoniae, and the susceptibility patterns of this strain for clarithromycin
Fig. 1. Schematic structure of the point mutations in domain V of 23S rRNA and range of minimum inhibitory concentrations (MICs) for macrolide and/or clindamycin-resistant Propionibacterium acnes. The MIC ranges for the following 15 macrolide-resistant P. acnes isolates are shown; 12 strains with 2058A!G in the 23S rRNA, 2 strains with 2059A!G in the 23S rRNA, and 1 strain with 2611C!G in the 23S rRNA [3].
http://dx.doi.org/10.1016/j.jgar.2016.05.005 2213-7165/ß 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.
Letter to the Editor / Journal of Global Antimicrobial Resistance 6 (2016) 160–161
(MIC = 100 mg/mL), spiramycin (MIC = 0.78 mg/mL) and clindamycin (MIC = 0.05 mg/mL) were quite similar to those of P. acnes strain 68b [5]. As with S. pneumoniae, we found that P. acnes harbouring a 2611C!G mutation in the 23S rRNA gene exhibited high-level resistance only to clarithromycin. In conclusion, a novel 23S rRNA mutation that confers resistance only to 14-membered macrolides was found in P. acnes. The 2611C!G mutation in the 23S rRNA gene of P. acnes is a novel group, as the resistance pattern of strains harbouring this mutation does not belong to any of the macrolide resistance groups defined by Ross et al. [2]. Further in vitro analysis is necessary to demonstrate how the 2611C!G mutation in the 23S rRNA gene is induced by use of macrolides. 1. Funding This work was supported by the Matching Fund Subsidy for Private Schools of Japan. 2. Competing interests None declared. 3. Ethical approval Not required. References [1] Sardana K, Gupta T, Garg VK, Ghunawat S. Antibiotic resistance to Propionobacterium acnes: worldwide scenario, diagnosis and management. Expert Rev Anti Infect Ther 2015;13:883–96. [2] Ross JI, Eady EA, Carnegie E, Cove JH. Detection of transposon Tn5432-mediated macrolide–lincosamide–streptogramin B (MLSB) resistance in cutaneous propionibacteria from six European cities. J Antimicrob Chemother 2002;49: 165–8. [3] Nakase K, Nakaminami H, Takenaka Y, Hayashi N, Kawashima M, Noguchi N. Relationship between the severity of acne vulgaris and antimicrobial resistance
161
of bacteria isolated from acne lesions in a hospital in Japan. J Med Microbiol 2014;63:721–8. [4] Vester B, Douthwaite S. Macrolide resistance conferred by base substitutions in 23S rRNA. Antimicrob Agents Chemother 2001;45:1–12. [5] Tait-Kamradt A, Davies T, Cronan M, Jacobs MR, Appelbaum PC, Sutcliffe J. Mutations in 23S rRNA and ribosomal protein L4 account for resistance in pneumococcal strains selected in vitro by macrolide passage. Antimicrob Agents Chemother 2000;44:2118–25.
Keisuke Nakase Hidemasa Nakaminami Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan Yuko Takenaka Department of Dermatology, Tokyo Women’s Medical University, 8-1 Kawadachou, Shinjuku-ku, Tokyo 162-8666, Japan Nobukazu Hayashi Department of Dermatology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan Makoto Kawashima Department of Dermatology, Tokyo Women’s Medical University, 8-1 Kawadachou, Shinjuku-ku, Tokyo 162-8666, Japan Norihisa Noguchi* Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan *Corresponding
author. Tel.: +81 426 76 5619; fax: +81 426 76 5647 E-mail address: [email protected] (N. Noguchi). 9 March 2016
Contents lists available at ScienceDirect
Journal of Global Antimicrobial Resistance journal homepage: www.elsevier.com/locate/jgar
Letter to the Editor A novel 23S rRNA mutation in Propionibacterium acnes confers resistance to 14-membered macrolides Sir, Propionibacterium acnes is a major pathogenic factor of acne vulgaris. Antimicrobial agents are used in treatment targeting this bacterium; traditionally, oral and topical macrolides have frequently been used for this purpose. As a result, macrolide-resistant P. acnes exhibiting cross-resistance to clindamycin has been widely disseminated worldwide [1]. Macrolide/clindamycin-resistant P. acnes has been categorised into four groups according to differences in the resistance factors and antibiotic susceptibility [2]. Strains belonging to three of the four groups harbour a mutation at positions 2057, 2058 and 2059, respectively, related to domain V, of 23S rRNA, and strains belonging to these groups are the most predominant in macrolideresistant P. acnes. Susceptibility to macrolides and clindamycin differs according to the point mutation that the strains harbour. Strains belonging to the fourth group harbour the erm(X) gene, which is responsible for dimethylation of 23S rRNA [2]. Although dissemination of clinical P. acnes isolates harbouring the erm(X) gene is rare, these strains exhibit the highest level of resistance to macrolides and clindamycin [2]. In this study, novel mechanisms of resistance to macrolides in P. acnes isolated from patients with acne vulgaris since 2009 in Japan were investigated. During this period, a macrolide-resistant strain was found that had no known resistance determinants. Here we show that a novel 23S rRNA mutation in P. acnes confers resistance to 14-membered macrolides. Sixteen macrolide-resistant P. acnes strains isolated at Tokyo Woman’s Medical University Hospital (Tokyo, Japan) were used in this study. Among them, a strain (68b) was observed that exhibited high-level resistance to clarithromycin [minimum inhibitory concentration (MIC) 256 mg/mL] but was susceptible to spiramycin (MIC = 1 mg/mL) and clindamycin (MIC = 0.25 mg/ mL) [3]. Strain 68b was identified as type II and K1 for recA typing and single-locus sequence type, respectively. According to an interview sheet, the patient in whom this strain was detected was diagnosed with moderate acne vulgaris and did not use any antibiotics. There are only a few reports describing mobile genetic elements, such as plasmids and transposons, in P. acnes, and dissemination of the erm(X) derived from Corynebacterium is rare. In addition, the susceptibility pattern of strain 68b to macrolides and clindamycin was similar to that of strains harbouring a mutation at positions 2057 2059 in the 23S rRNA gene. Therefore, we presumed that strain 68b had a mutation in the 23S rRNA gene. Sequencing analyses of the strain were performed for positions 748 and 752 at domain II, which is located adjacent to domain V,
and for position 2610 at domain V of 23S rRNA. Simultaneously, the rplD and rplV genes for ribosomal proteins L4 and L22, respectively, were also sequenced. The results of the analyses showed that strain 68b harboured a novel cytosine to guanine mutation at position 2611 (2611C!G) in the 23S rRNA gene (Fig. 1). Of the other 15 macrolide-resistant strains, erm(X) was detected from 1 strain, and the other strains harboured the 2058A!G or 2059A!G mutation in the 23S rRNA gene [3]. Compared with the other resistant strains, the strain harbouring 2611C!G in the 23S rRNA gene exhibited susceptibility to spiramycin (a 16-membered macrolide) and clindamycin (a lincosamide), similar to the susceptible strains (Fig. 1). The sequence was verified by BLAST analysis against the GenBank database to check whether the 2611C!G mutation had already been reported; the mutation has not been deposited in the GenBank database. None of the strains tested in this study exhibited multiple resistance factors. In addition, none of the strains harboured mutations at domain II and position G2057 of 23S rRNA, or in the rplD and rplV genes. Mutation at position 2611 in the 23S rRNA gene has been reported in Escherichia coli and Chlamydomonas [4]. Furthermore, the mutation has also been detected in Streptococcus pneumoniae, and the susceptibility patterns of this strain for clarithromycin
Fig. 1. Schematic structure of the point mutations in domain V of 23S rRNA and range of minimum inhibitory concentrations (MICs) for macrolide and/or clindamycin-resistant Propionibacterium acnes. The MIC ranges for the following 15 macrolide-resistant P. acnes isolates are shown; 12 strains with 2058A!G in the 23S rRNA, 2 strains with 2059A!G in the 23S rRNA, and 1 strain with 2611C!G in the 23S rRNA [3].
http://dx.doi.org/10.1016/j.jgar.2016.05.005 2213-7165/ß 2016 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.
Letter to the Editor / Journal of Global Antimicrobial Resistance 6 (2016) 160–161
(MIC = 100 mg/mL), spiramycin (MIC = 0.78 mg/mL) and clindamycin (MIC = 0.05 mg/mL) were quite similar to those of P. acnes strain 68b [5]. As with S. pneumoniae, we found that P. acnes harbouring a 2611C!G mutation in the 23S rRNA gene exhibited high-level resistance only to clarithromycin. In conclusion, a novel 23S rRNA mutation that confers resistance only to 14-membered macrolides was found in P. acnes. The 2611C!G mutation in the 23S rRNA gene of P. acnes is a novel group, as the resistance pattern of strains harbouring this mutation does not belong to any of the macrolide resistance groups defined by Ross et al. [2]. Further in vitro analysis is necessary to demonstrate how the 2611C!G mutation in the 23S rRNA gene is induced by use of macrolides. 1. Funding This work was supported by the Matching Fund Subsidy for Private Schools of Japan. 2. Competing interests None declared. 3. Ethical approval Not required. References [1] Sardana K, Gupta T, Garg VK, Ghunawat S. Antibiotic resistance to Propionobacterium acnes: worldwide scenario, diagnosis and management. Expert Rev Anti Infect Ther 2015;13:883–96. [2] Ross JI, Eady EA, Carnegie E, Cove JH. Detection of transposon Tn5432-mediated macrolide–lincosamide–streptogramin B (MLSB) resistance in cutaneous propionibacteria from six European cities. J Antimicrob Chemother 2002;49: 165–8. [3] Nakase K, Nakaminami H, Takenaka Y, Hayashi N, Kawashima M, Noguchi N. Relationship between the severity of acne vulgaris and antimicrobial resistance
161
of bacteria isolated from acne lesions in a hospital in Japan. J Med Microbiol 2014;63:721–8. [4] Vester B, Douthwaite S. Macrolide resistance conferred by base substitutions in 23S rRNA. Antimicrob Agents Chemother 2001;45:1–12. [5] Tait-Kamradt A, Davies T, Cronan M, Jacobs MR, Appelbaum PC, Sutcliffe J. Mutations in 23S rRNA and ribosomal protein L4 account for resistance in pneumococcal strains selected in vitro by macrolide passage. Antimicrob Agents Chemother 2000;44:2118–25.
Keisuke Nakase Hidemasa Nakaminami Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan Yuko Takenaka Department of Dermatology, Tokyo Women’s Medical University, 8-1 Kawadachou, Shinjuku-ku, Tokyo 162-8666, Japan Nobukazu Hayashi Department of Dermatology, Toranomon Hospital, 2-2-2 Toranomon, Minato-ku, Tokyo 105-8470, Japan Makoto Kawashima Department of Dermatology, Tokyo Women’s Medical University, 8-1 Kawadachou, Shinjuku-ku, Tokyo 162-8666, Japan Norihisa Noguchi* Department of Microbiology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 1920392, Japan *Corresponding
author. Tel.: +81 426 76 5619; fax: +81 426 76 5647 E-mail address: [email protected] (N. Noguchi). 9 March 2016