Research letters
Funding
Staphylococcus aureus Surveillance Programme. J Glob Antimicrob Resist 2013; 1: 149–56.
This study was financially supported by the Pork Cooperative Research Centre Ltd and Australian Pork Ltd.
14 Turner AJ. Quarantine, exports and animal disease in Australia 1901– 2010. Aust Vet J 2011; 89: 366– 71. 15 Australian Bureau of Statistics. 2009–10 Year Book Australia. Canberra: Commonwealth of Australia, 2010.
Transparency declarations M. D. G., H. J. M. B. and T. A. C. have received funding from the Pork Cooperative Research Centre Ltd (Australia) and Australian Pork Ltd. S. A. and D. J. T. have received funding from Zoetis for research. D. J. has received funds from Meat and Livestock Australia for research advising on food safety issues. All other authors: none to declare.
17 Callinan I. Equine Influenza: The August 2007 Outbreak in Australia— Report of the Equine Influenza Inquiry. Canberra: Commonwealth of Australia, 2008. 18 National Management Group on TSEs and FMD. Report to Australian Government Primary Industries Ministerial Council—Annex C. http://www. daff.gov.au/__data/assets/pdf_file/0005/316346/pimc_res1_10_AnnexC. pdf (23 August 2013, date last accessed).
1 Garcia-Alvarez L, Dawson S, Cookson B et al. Working across the veterinary and human health sectors. J Antimicrob Chemother 2012; 67 Suppl 1: i37–49. 2 Trott D, Jordan D, Barton M et al. Vets versus pets: methicillin-resistant Staphylococcus aureus in Australian animals and their doctors. Microbiol Aust 2013; 34: 25 –7. 3 Jonas D, Speck M, Daschner FD et al. Rapid PCR-based identification of methicillin-resistant Staphylococcus aureus from screening swabs. J Clin Microbiol 2002; 40: 1821– 3. 4 Graveland H, Wagenaar JA, Heesterbeek H et al. Methicillin resistant Staphylococcus aureus ST398 in veal calf farming: human MRSA carriage related with animal antimicrobial usage and farm hygiene. PLoS One 2010; 5: e10990. 5 Cai L, Kong F, Wang Q et al. A new multiplex PCR-based reverse line-blot hybridization (mPCR/RLB) assay for rapid staphylococcal cassette chromosome mec (SCCmec) typing. J Med Microbiol 2009; 58: 1045 –57. 6 Feßler A, Scott C, Kadlec K et al. Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. J Antimicrob Chemother 2010; 65: 619–25. 7 O’Sullivan MVN, Zhou F, Sintchenko V et al. Prospective genotyping of hospital-acquired methicillin-resistant Staphylococcus aureus isolates by use of a novel, highly discriminatory binary typing system. J Clin Microbiol 2012; 50: 3513– 9.
J Antimicrob Chemother 2014 doi:10.1093/jac/dkt499 Advance Access publication 22 December 2013
Emergence and molecular characterization of clonal complex 398 (CC398) methicillin-resistant Staphylococcus aureus (MRSA) in New Zealand Deborah A. Williamson1,2*, Sarah Bakker1, Geoffrey W. Coombs3,4, Hui leen Tan3, Stefan Monecke5,6 and Helen Heffernan1 1
9 Harmsen D, Claus H, Witte W et al. Typing of methicillin-resistant Staphylococcus aureus in a university hospital setting by using novel software for spa repeat determination and database management. J Clin Microbiol 2003; 41: 5442– 8.
Institute of Environmental Science and Research, Wellington, New Zealand; 2Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; 3Australian Collaborating Centre for Enterococcus and Staphylococcus Species (ACCESS) Typing and Research, School of Biomedical Sciences, Curtin University, Western Australia, Australia; 4Department of Microbiology and Infectious Diseases, PathWest Laboratory Medicine, Royal Perth Hospital, Western Australia, Australia; 5Technical University of Dresden, Dresden, Germany; 6Alere Technologies, Jena, Germany
10 Goering RV, Morrison D, Al-Doori Z et al. Usefulness of mec-associated direct repeat unit (dru) typing in the epidemiological analysis of highly clonal methicillin-resistant Staphylococcus aureus in Scotland. Clin Microbiol Infect 2008; 14: 964– 9.
*Corresponding author. Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand. Tel: +64-9-373-7599; Fax: +64-9-307-6922; E-mail: [email protected]
8 Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing: Twenty-second Informational Supplement M100-S22. CLSI, Wayne, PA, USA, 2012.
11 van Cleef BAGL, Monnet DL, Voss A et al. Livestock-associated methicillin-resistant Staphylococcus aureus in humans, Europe. Emerg Infect Dis 2011; 17: 502–5.
Keywords: zoonoses, staphylococcal infections, infectious
12 Feßler AT, Kadlec K, Hassel M et al. Characterization of methicillinresistant Staphylococcus aureus isolates from food and food products of poultry origin in Germany. Appl Environ Microbiol 2011; 77: 7151–7.
Sir, Of increasing public health importance is the recognition that livestock, most notably swine, poultry and veal calves, act as reservoirs of methicillin-resistant Staphylococcus aureus (MRSA) strains.1 Livestock-associated MRSA (LA-MRSA) strains can effectively colonize and infect humans, with subsequent transmission in both community and healthcare settings.2,3 To date, the most
13 Coombs GW, Pearson JC, Nimmo GR et al. Antimicrobial susceptibility of Staphylococcus aureus and molecular epidemiology of meticillinresistant S. aureus isolated from Australian hospital inpatients: report from the Australian Group on Antimicrobial Resistance 2011
1428
diseases epidemiology
Downloaded from http://jac.oxfordjournals.org/ at Umea universitet on October 13, 2014
References
16 Slingerland BCGC, Tavakol M, McCarthy AJ et al. Survival of Staphylococcus aureus ST398 in the human nose after artificial inoculation. PLoS One 2012; 7: e48896.
JAC scn, chp, sak scn, chp, sak — — — — — — — bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD MSCRAMM, microbial surface components recognizing adhesive matrix molecules.
tet(K), erm(A) tet(K), erm(A) tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(M), blaZ tet(K), tet(M), erm(C) blaZ tet(K), tet(M), blaZ present present absent absent absent absent absent absent absent V V V V V V V V V ST1232 ST1232 ST398 ST398 ST398 ST398 ST398 ST398 ST398 t034 t034 t011 t011 t011 t011 t571 t011 t011 wound swab wound swab sputum wound swab wound swab wound swab wound swab screening swab screening swab 1 2 3 4 5 6 7 8 9
MRS11/2176 MRS11/2552 MRS11/2230 MRS11/3424 MRS12/870 MRS13/846 MRS13/904 MRS13/1037 MRS13/1089
Antimicrobial resistance genes Specimen type Patient
Isolate
spa type
MLST
lukF-PV/ SCCmec lukS-PV type genes
Table 1. Clinical and microbiological characteristics of human CC398 MRSA infections, New Zealand, 2011 –13
commonly reported LA-MRSA strains are those that belong to clonal complex 398 (CC398).1 Recent reports suggest that CC398 MRSA accounts for up to 25% of all community-associated MRSA in some parts of Europe.2 Moreover, CC398 MRSA has also been reported from several other geographic regions, including Singapore, China and North and Central America.4 To date, however, there have been no reports of LA-MRSA CC398 strains from New Zealand, a country noted for its strong agricultural industry. Here, we describe the first identification and molecular characterization of CC398 MRSA isolates from nine patients in New Zealand. In New Zealand, molecular characterization of MRSA isolates is performed at the Institute of Environmental Science and Research. Molecular typing of MRSA isolates is performed by spa typing and, when necessary, isolates are further characterized by multilocus sequence typing (MLST). Between August 2011 and May 2013, MRSA isolates from nine patients were found to belong to CC398. By spa typing, these isolates were spa t011 (six isolates), spa t034 (two isolates) or spa t571 (one isolate) (Table 1). All nine patients resided in the South Island of New Zealand. Three of the patients with spa t011 CC398 either resided on a pig farm or had recently handled swine carcasses. All isolates tested non-susceptible to penicillin, oxacillin and tetracycline. The two spa t034 isolates also tested non-susceptible to erythromycin, as did one of the spa t011 isolates (MRS13/1037), which also displayed constitutive resistance to clindamycin. The isolates were susceptible to all other tested antimicrobials. By MLST, the two spa t034 isolates were ST1232 (a single-locus variant of ST398 belonging to CC398) and all seven remaining isolates were ST398. Further molecular characterization of MRSA isolates was performed by DNA microarray analysis (StaphType, CLONDIAG, Germany) using previously described methods. 5 This demonstrated the presence of the mecA gene and the type V SCCmec element (where SCC stands for staphylococcal cassette chromosome) in all isolates. In keeping with other reports of CC398 strains, all nine isolates belonged to agr group I.6 All isolates, except the spa t571 isolate, contained the tet(K) gene, while all isolates, except the two spa t034 isolates, contained the tet(M) gene. The two spa t034 isolates contained the erm(A) gene and one of the spa t011 isolates (MRS13/1037) contained the erm(C) gene. Of note, the blaZ gene and its accompanying regulatory blaI and blaR genes were not detected by DNA microarray in the two spa t034 isolates (Table 1). Tests for induced b-lactamase using nitrocefin were also negative for these two isolates, further supporting the absence of the blaZ gene. Interestingly, both spa t034 isolates harboured the lukF-PV and lukS-PV genes encoding Panton – Valentine leucocidin (PVL). Although infrequent, human cases of PVL-positive CC398 MRSA infections have been described from Sweden, Finland and China.4,7,8 Of note, two of these previous cases of PVL-positive CC398 in Sweden had an epidemiological link to Asia,8 similar to one of our patients with PVL-positive spa t034 CC398 who had a recent travel history to South-East Asia. None of the nine CC398 isolates contained genes encoding either toxic shock syndrome toxin 1 or any staphylococcal enterotoxins (Table 1). All isolates had a variety of genes encoding proteins associated with biofilm formation,1,9 including clfA and clfB (clumping factors A and B), cna (collagen-binding adhesin), fnbA and fnbB (fibronectin-binding proteins A and B) and bbp (bone sialoprotein-binding protein). The allelic variants of these genes
1429
Downloaded from http://jac.oxfordjournals.org/ at Umea universitet on October 13, 2014
Capsule and biofilm-associated genes
Selected adhesion factor and MSCRAMM genes
Other virulenceassociated genes
Research letters
Research letters
8 Welinder-Olsson C, Floren-Johansson K, Larsson L et al. Infection with Panton– Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus t034. Emerg Infect Dis 2008; 14: 1271–2. 9 Fessler A, Scott C, Kadlec K et al. Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. J Antimicrob Chemother 2010; 65: 619–25.
J Antimicrob Chemother 2014 doi:10.1093/jac/dkt498 Advance Access publication 18 December 2013
A subclass B3 metallo-b-lactamase found in Pseudomonas alcaligenes Masato Suzuki1*, Satowa Suzuki1, Mari Matsui1, Yoichi Hiraki2, Fumio Kawano3 and Keigo Shibayama1 1
Acknowledgements We thank Mona Schousboe and Antje van der Linden for referral of the isolates and initial patient follow-up.
Funding This study was supported by internal funding. D. A. W. is a Clinical Research Training Fellow of the Health Research Council of New Zealand.
Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan; 2Department of Pharmacy, National Hospital Organization Kumamoto Medical Center, 1-5 Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan; 3Department of Hematology, National Hospital Organization Kumamoto Medical Center, 1-5 Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan *Corresponding author. Tel: +81-42-561-0771; Fax: +81-42-561-7173; E-mail: [email protected]
Keywords: nosocomial infections, drug resistance, bacterial
genomics
Transparency declarations None to declare.
References 1 Fluit AC. Livestock-associated Staphylococcus aureus. Clin Microbiol Infect 2012; 18: 735– 44. 2 van Cleef BA, Monnet DL, Voss A et al. Livestock-associated methicillin-resistant Staphylococcus aureus in humans, Europe. Emerg Infect Dis 2011; 17: 502–5. 3 Verkade E, Bosch T, Hendriks Y et al. Outbreak of methicillin-resistant Staphylococcus aureus ST398 in a Dutch nursing home. Infect Control Hosp Epidemiol 2012; 33: 624– 6. 4 David MZ, Daum RS. Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic. Clin Microbiol Rev 2010; 23: 616–87. 5 Monecke S, Jatzwauk L, Weber S et al. DNA microarray-based genotyping of methicillin-resistant Staphylococcus aureus strains from Eastern Saxony. Clin Microbiol Infect 2008; 14: 534– 45. 6 Lozano C, Rezusta A, Gomez P et al. High prevalence of spa types associated with the clonal lineage CC398 among tetracycline-resistant methicillin-resistant Staphylococcus aureus strains in a Spanish hospital. J Antimicrob Chemother 2012; 67: 330–4. 7 Salmenlinna S, Lyytikainen O, Vainio A et al. Human cases of methicillin-resistant Staphylococcus aureus CC398, Finland. Emerg Infect Dis 2010; 16: 1626– 9.
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Sir, Metallo-b-lactamase (MBL) is an important resistance determinant among Gram-negative bacteria, and its clinical relevance is increasing.1 Some MBL genes are carried on mobile gene elements that have spread among various clinically important bacterial species.1 Here we report a case of a novel MBL-positive Pseudomonas alcaligenes strain, MRY13-0052, that caused a bloodstream infection in a medical institution in Japan.2 P. alcaligenes is a Gram-negative aerobic bacillus belonging to the bacterial family Pseudomonadaceae, the members of which are common inhabitants of soil and water, and it is a rare opportunistic human pathogen.3 However, little is known about the clinical importance of P. alcaligenes, mainly because of the difficulties in identifying and distinguishing this bacterium from closely related Pseudomonas species, such as Pseudomonas aeruginosa, Pseudomonas mendocina and Pseudomonas pseudoalcaligenes, in medical settings. We report here our investigation of the draft genome sequence of P. alcaligenes strain MRY13-0052 and our finding that this strain contains a subclass B3 MBL,4 PAM-1 (P. alcaligenes MBL-1), that can hydrolyse cephalosporins and carbapenems. In 2012, Pseudomonas strain MRY13-0052 was recovered from a blood sample of a patient who was receiving therapy for Guillain –Barre´ syndrome. The patient had no recent history of travel abroad. Although the primary site of infection was unknown, the patient became afebrile soon after combination therapy
Downloaded from http://jac.oxfordjournals.org/ at Umea universitet on October 13, 2014
were similar to those described from other CC398 strains.1,9 In addition, both PVL-positive spa t034 isolates contained genes associated with hlb-converting phages, namely sak, chp and scn. Although we did not have detailed epidemiological information on all nine patients, it is notable that three of the patients in this study had recent exposure to pigs. In other settings, isolation of CC398 MRSA has been strongly associated with exposure to livestock, including pigs, poultry and calves.2 This association with livestock may be of particular relevance in our geographic setting, given the large rural and agricultural sector in New Zealand. To our knowledge, these cases represent the first known human isolations of CC398 MRSA in New Zealand. We found two clusters of CC398 MRSA, each with distinct characteristics. One cluster was due to a PVL-positive spa t034 ST1232 MRSA strain, which was associated with travel to South-East Asia, and the other cluster was due to a PVL-negative spa t011 or spa t571 ST398 strain, similar to the European LA-MRSA lineage. Ongoing clinical and molecular surveillance is essential to monitor the spread of these MRSA strains in our country.
Funding
Staphylococcus aureus Surveillance Programme. J Glob Antimicrob Resist 2013; 1: 149–56.
This study was financially supported by the Pork Cooperative Research Centre Ltd and Australian Pork Ltd.
14 Turner AJ. Quarantine, exports and animal disease in Australia 1901– 2010. Aust Vet J 2011; 89: 366– 71. 15 Australian Bureau of Statistics. 2009–10 Year Book Australia. Canberra: Commonwealth of Australia, 2010.
Transparency declarations M. D. G., H. J. M. B. and T. A. C. have received funding from the Pork Cooperative Research Centre Ltd (Australia) and Australian Pork Ltd. S. A. and D. J. T. have received funding from Zoetis for research. D. J. has received funds from Meat and Livestock Australia for research advising on food safety issues. All other authors: none to declare.
17 Callinan I. Equine Influenza: The August 2007 Outbreak in Australia— Report of the Equine Influenza Inquiry. Canberra: Commonwealth of Australia, 2008. 18 National Management Group on TSEs and FMD. Report to Australian Government Primary Industries Ministerial Council—Annex C. http://www. daff.gov.au/__data/assets/pdf_file/0005/316346/pimc_res1_10_AnnexC. pdf (23 August 2013, date last accessed).
1 Garcia-Alvarez L, Dawson S, Cookson B et al. Working across the veterinary and human health sectors. J Antimicrob Chemother 2012; 67 Suppl 1: i37–49. 2 Trott D, Jordan D, Barton M et al. Vets versus pets: methicillin-resistant Staphylococcus aureus in Australian animals and their doctors. Microbiol Aust 2013; 34: 25 –7. 3 Jonas D, Speck M, Daschner FD et al. Rapid PCR-based identification of methicillin-resistant Staphylococcus aureus from screening swabs. J Clin Microbiol 2002; 40: 1821– 3. 4 Graveland H, Wagenaar JA, Heesterbeek H et al. Methicillin resistant Staphylococcus aureus ST398 in veal calf farming: human MRSA carriage related with animal antimicrobial usage and farm hygiene. PLoS One 2010; 5: e10990. 5 Cai L, Kong F, Wang Q et al. A new multiplex PCR-based reverse line-blot hybridization (mPCR/RLB) assay for rapid staphylococcal cassette chromosome mec (SCCmec) typing. J Med Microbiol 2009; 58: 1045 –57. 6 Feßler A, Scott C, Kadlec K et al. Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. J Antimicrob Chemother 2010; 65: 619–25. 7 O’Sullivan MVN, Zhou F, Sintchenko V et al. Prospective genotyping of hospital-acquired methicillin-resistant Staphylococcus aureus isolates by use of a novel, highly discriminatory binary typing system. J Clin Microbiol 2012; 50: 3513– 9.
J Antimicrob Chemother 2014 doi:10.1093/jac/dkt499 Advance Access publication 22 December 2013
Emergence and molecular characterization of clonal complex 398 (CC398) methicillin-resistant Staphylococcus aureus (MRSA) in New Zealand Deborah A. Williamson1,2*, Sarah Bakker1, Geoffrey W. Coombs3,4, Hui leen Tan3, Stefan Monecke5,6 and Helen Heffernan1 1
9 Harmsen D, Claus H, Witte W et al. Typing of methicillin-resistant Staphylococcus aureus in a university hospital setting by using novel software for spa repeat determination and database management. J Clin Microbiol 2003; 41: 5442– 8.
Institute of Environmental Science and Research, Wellington, New Zealand; 2Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand; 3Australian Collaborating Centre for Enterococcus and Staphylococcus Species (ACCESS) Typing and Research, School of Biomedical Sciences, Curtin University, Western Australia, Australia; 4Department of Microbiology and Infectious Diseases, PathWest Laboratory Medicine, Royal Perth Hospital, Western Australia, Australia; 5Technical University of Dresden, Dresden, Germany; 6Alere Technologies, Jena, Germany
10 Goering RV, Morrison D, Al-Doori Z et al. Usefulness of mec-associated direct repeat unit (dru) typing in the epidemiological analysis of highly clonal methicillin-resistant Staphylococcus aureus in Scotland. Clin Microbiol Infect 2008; 14: 964– 9.
*Corresponding author. Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand. Tel: +64-9-373-7599; Fax: +64-9-307-6922; E-mail: [email protected]
8 Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing: Twenty-second Informational Supplement M100-S22. CLSI, Wayne, PA, USA, 2012.
11 van Cleef BAGL, Monnet DL, Voss A et al. Livestock-associated methicillin-resistant Staphylococcus aureus in humans, Europe. Emerg Infect Dis 2011; 17: 502–5.
Keywords: zoonoses, staphylococcal infections, infectious
12 Feßler AT, Kadlec K, Hassel M et al. Characterization of methicillinresistant Staphylococcus aureus isolates from food and food products of poultry origin in Germany. Appl Environ Microbiol 2011; 77: 7151–7.
Sir, Of increasing public health importance is the recognition that livestock, most notably swine, poultry and veal calves, act as reservoirs of methicillin-resistant Staphylococcus aureus (MRSA) strains.1 Livestock-associated MRSA (LA-MRSA) strains can effectively colonize and infect humans, with subsequent transmission in both community and healthcare settings.2,3 To date, the most
13 Coombs GW, Pearson JC, Nimmo GR et al. Antimicrobial susceptibility of Staphylococcus aureus and molecular epidemiology of meticillinresistant S. aureus isolated from Australian hospital inpatients: report from the Australian Group on Antimicrobial Resistance 2011
1428
diseases epidemiology
Downloaded from http://jac.oxfordjournals.org/ at Umea universitet on October 13, 2014
References
16 Slingerland BCGC, Tavakol M, McCarthy AJ et al. Survival of Staphylococcus aureus ST398 in the human nose after artificial inoculation. PLoS One 2012; 7: e48896.
JAC scn, chp, sak scn, chp, sak — — — — — — — bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna bbp, clfA, clfB, fnbA, fnbB, cna cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD cap5, icaA, icaC, icaD MSCRAMM, microbial surface components recognizing adhesive matrix molecules.
tet(K), erm(A) tet(K), erm(A) tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(K), tet(M), blaZ tet(M), blaZ tet(K), tet(M), erm(C) blaZ tet(K), tet(M), blaZ present present absent absent absent absent absent absent absent V V V V V V V V V ST1232 ST1232 ST398 ST398 ST398 ST398 ST398 ST398 ST398 t034 t034 t011 t011 t011 t011 t571 t011 t011 wound swab wound swab sputum wound swab wound swab wound swab wound swab screening swab screening swab 1 2 3 4 5 6 7 8 9
MRS11/2176 MRS11/2552 MRS11/2230 MRS11/3424 MRS12/870 MRS13/846 MRS13/904 MRS13/1037 MRS13/1089
Antimicrobial resistance genes Specimen type Patient
Isolate
spa type
MLST
lukF-PV/ SCCmec lukS-PV type genes
Table 1. Clinical and microbiological characteristics of human CC398 MRSA infections, New Zealand, 2011 –13
commonly reported LA-MRSA strains are those that belong to clonal complex 398 (CC398).1 Recent reports suggest that CC398 MRSA accounts for up to 25% of all community-associated MRSA in some parts of Europe.2 Moreover, CC398 MRSA has also been reported from several other geographic regions, including Singapore, China and North and Central America.4 To date, however, there have been no reports of LA-MRSA CC398 strains from New Zealand, a country noted for its strong agricultural industry. Here, we describe the first identification and molecular characterization of CC398 MRSA isolates from nine patients in New Zealand. In New Zealand, molecular characterization of MRSA isolates is performed at the Institute of Environmental Science and Research. Molecular typing of MRSA isolates is performed by spa typing and, when necessary, isolates are further characterized by multilocus sequence typing (MLST). Between August 2011 and May 2013, MRSA isolates from nine patients were found to belong to CC398. By spa typing, these isolates were spa t011 (six isolates), spa t034 (two isolates) or spa t571 (one isolate) (Table 1). All nine patients resided in the South Island of New Zealand. Three of the patients with spa t011 CC398 either resided on a pig farm or had recently handled swine carcasses. All isolates tested non-susceptible to penicillin, oxacillin and tetracycline. The two spa t034 isolates also tested non-susceptible to erythromycin, as did one of the spa t011 isolates (MRS13/1037), which also displayed constitutive resistance to clindamycin. The isolates were susceptible to all other tested antimicrobials. By MLST, the two spa t034 isolates were ST1232 (a single-locus variant of ST398 belonging to CC398) and all seven remaining isolates were ST398. Further molecular characterization of MRSA isolates was performed by DNA microarray analysis (StaphType, CLONDIAG, Germany) using previously described methods. 5 This demonstrated the presence of the mecA gene and the type V SCCmec element (where SCC stands for staphylococcal cassette chromosome) in all isolates. In keeping with other reports of CC398 strains, all nine isolates belonged to agr group I.6 All isolates, except the spa t571 isolate, contained the tet(K) gene, while all isolates, except the two spa t034 isolates, contained the tet(M) gene. The two spa t034 isolates contained the erm(A) gene and one of the spa t011 isolates (MRS13/1037) contained the erm(C) gene. Of note, the blaZ gene and its accompanying regulatory blaI and blaR genes were not detected by DNA microarray in the two spa t034 isolates (Table 1). Tests for induced b-lactamase using nitrocefin were also negative for these two isolates, further supporting the absence of the blaZ gene. Interestingly, both spa t034 isolates harboured the lukF-PV and lukS-PV genes encoding Panton – Valentine leucocidin (PVL). Although infrequent, human cases of PVL-positive CC398 MRSA infections have been described from Sweden, Finland and China.4,7,8 Of note, two of these previous cases of PVL-positive CC398 in Sweden had an epidemiological link to Asia,8 similar to one of our patients with PVL-positive spa t034 CC398 who had a recent travel history to South-East Asia. None of the nine CC398 isolates contained genes encoding either toxic shock syndrome toxin 1 or any staphylococcal enterotoxins (Table 1). All isolates had a variety of genes encoding proteins associated with biofilm formation,1,9 including clfA and clfB (clumping factors A and B), cna (collagen-binding adhesin), fnbA and fnbB (fibronectin-binding proteins A and B) and bbp (bone sialoprotein-binding protein). The allelic variants of these genes
1429
Downloaded from http://jac.oxfordjournals.org/ at Umea universitet on October 13, 2014
Capsule and biofilm-associated genes
Selected adhesion factor and MSCRAMM genes
Other virulenceassociated genes
Research letters
Research letters
8 Welinder-Olsson C, Floren-Johansson K, Larsson L et al. Infection with Panton– Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus t034. Emerg Infect Dis 2008; 14: 1271–2. 9 Fessler A, Scott C, Kadlec K et al. Characterization of methicillin-resistant Staphylococcus aureus ST398 from cases of bovine mastitis. J Antimicrob Chemother 2010; 65: 619–25.
J Antimicrob Chemother 2014 doi:10.1093/jac/dkt498 Advance Access publication 18 December 2013
A subclass B3 metallo-b-lactamase found in Pseudomonas alcaligenes Masato Suzuki1*, Satowa Suzuki1, Mari Matsui1, Yoichi Hiraki2, Fumio Kawano3 and Keigo Shibayama1 1
Acknowledgements We thank Mona Schousboe and Antje van der Linden for referral of the isolates and initial patient follow-up.
Funding This study was supported by internal funding. D. A. W. is a Clinical Research Training Fellow of the Health Research Council of New Zealand.
Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan; 2Department of Pharmacy, National Hospital Organization Kumamoto Medical Center, 1-5 Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan; 3Department of Hematology, National Hospital Organization Kumamoto Medical Center, 1-5 Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan *Corresponding author. Tel: +81-42-561-0771; Fax: +81-42-561-7173; E-mail: [email protected]
Keywords: nosocomial infections, drug resistance, bacterial
genomics
Transparency declarations None to declare.
References 1 Fluit AC. Livestock-associated Staphylococcus aureus. Clin Microbiol Infect 2012; 18: 735– 44. 2 van Cleef BA, Monnet DL, Voss A et al. Livestock-associated methicillin-resistant Staphylococcus aureus in humans, Europe. Emerg Infect Dis 2011; 17: 502–5. 3 Verkade E, Bosch T, Hendriks Y et al. Outbreak of methicillin-resistant Staphylococcus aureus ST398 in a Dutch nursing home. Infect Control Hosp Epidemiol 2012; 33: 624– 6. 4 David MZ, Daum RS. Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic. Clin Microbiol Rev 2010; 23: 616–87. 5 Monecke S, Jatzwauk L, Weber S et al. DNA microarray-based genotyping of methicillin-resistant Staphylococcus aureus strains from Eastern Saxony. Clin Microbiol Infect 2008; 14: 534– 45. 6 Lozano C, Rezusta A, Gomez P et al. High prevalence of spa types associated with the clonal lineage CC398 among tetracycline-resistant methicillin-resistant Staphylococcus aureus strains in a Spanish hospital. J Antimicrob Chemother 2012; 67: 330–4. 7 Salmenlinna S, Lyytikainen O, Vainio A et al. Human cases of methicillin-resistant Staphylococcus aureus CC398, Finland. Emerg Infect Dis 2010; 16: 1626– 9.
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Sir, Metallo-b-lactamase (MBL) is an important resistance determinant among Gram-negative bacteria, and its clinical relevance is increasing.1 Some MBL genes are carried on mobile gene elements that have spread among various clinically important bacterial species.1 Here we report a case of a novel MBL-positive Pseudomonas alcaligenes strain, MRY13-0052, that caused a bloodstream infection in a medical institution in Japan.2 P. alcaligenes is a Gram-negative aerobic bacillus belonging to the bacterial family Pseudomonadaceae, the members of which are common inhabitants of soil and water, and it is a rare opportunistic human pathogen.3 However, little is known about the clinical importance of P. alcaligenes, mainly because of the difficulties in identifying and distinguishing this bacterium from closely related Pseudomonas species, such as Pseudomonas aeruginosa, Pseudomonas mendocina and Pseudomonas pseudoalcaligenes, in medical settings. We report here our investigation of the draft genome sequence of P. alcaligenes strain MRY13-0052 and our finding that this strain contains a subclass B3 MBL,4 PAM-1 (P. alcaligenes MBL-1), that can hydrolyse cephalosporins and carbapenems. In 2012, Pseudomonas strain MRY13-0052 was recovered from a blood sample of a patient who was receiving therapy for Guillain –Barre´ syndrome. The patient had no recent history of travel abroad. Although the primary site of infection was unknown, the patient became afebrile soon after combination therapy
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were similar to those described from other CC398 strains.1,9 In addition, both PVL-positive spa t034 isolates contained genes associated with hlb-converting phages, namely sak, chp and scn. Although we did not have detailed epidemiological information on all nine patients, it is notable that three of the patients in this study had recent exposure to pigs. In other settings, isolation of CC398 MRSA has been strongly associated with exposure to livestock, including pigs, poultry and calves.2 This association with livestock may be of particular relevance in our geographic setting, given the large rural and agricultural sector in New Zealand. To our knowledge, these cases represent the first known human isolations of CC398 MRSA in New Zealand. We found two clusters of CC398 MRSA, each with distinct characteristics. One cluster was due to a PVL-positive spa t034 ST1232 MRSA strain, which was associated with travel to South-East Asia, and the other cluster was due to a PVL-negative spa t011 or spa t571 ST398 strain, similar to the European LA-MRSA lineage. Ongoing clinical and molecular surveillance is essential to monitor the spread of these MRSA strains in our country.
