Journal of Hospital Infection 86 (2014) 151e154 Available online at www.sciencedirect.com
Journal of Hospital Infection journal homepage: www.elsevierhealth.com/journals/jhin
Short report
Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital F.S. Cavalcante a, R.P. Schuenck b, D.C. Ferreira a, ´r c, K.R.N. dos Santos a, * C.R. da Costa c, S.A. Noue a
Departamento de Microbiologia Me´dica, Instituto de Microbiologia Paulo de Go´es, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil b Departamento de Patologia, Universidade Federal do Espirito Santo, Espirito Santo, Brazil c Hospital Universita´rio Clementino Fraga Filho e Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
A R T I C L E
I N F O
Article history: Received 14 June 2013 Accepted 4 December 2013 Available online 21 December 2013 Keywords: Clonal complex Colonization Hospital wards Lineages Meticillin-resistant Staphylococcus aureus Staphylococcal cassette chromosome mec
S U M M A R Y
This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), PantoneValentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P ¼ 0.002) whereas ‘clone M’ (SCCmec III) was more common in the medical and surgical intensive care unit (P ¼ 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures. ª 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of healthcare-associated infections and some lineages are globally spread. Meticillin resistance is due to the * Corresponding author. Address: Laborato ¸˜ oes Hospital´rio de Infecc ares, Departamento de Microbiologia Me ´dica, Instituto de Microbiologia Paulo de Go ´es, Universidade Federal do Rio de Janeiro, CCS, Bloco I, Sala 010, Cidade Universita ´ria, CEP: 21941-590 Rio de Janeiro, RJ, Brazil. Tel.: þ55 21 2560 8344; fax: þ55 21 2560 8028. E-mail address: [email protected] (K.R.N. dos Santos).
mecA gene, located in a staphylococcal cassette chromosome (SCCmec); the most frequent types are I, II, III and IV.1 In Brazil, isolates related to the ‘Brazilian epidemic clone’ (BEC) multi-locus sequence type (ST) 239, SCCmec III (ST239-III) lineage were responsible for 90% of nosocomial MRSA isolates in the late 1990s.2 However, over the last decade SCCmec IV isolates have emerged in our country. Currently, ST1-IV (USA400) and ST5-IV (USA800) are the most common lineages identified in Brazilian hospitals.3e5 Studies characterizing isolates from nasal colonization of inpatients in Brazil have not been described. Here, we investigated the molecular characteristics of MRSA isolates from
0195-6701/$ e see front matter ª 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jhin.2013.12.004
152
F.S. Cavalcante et al. / Journal of Hospital Infection 86 (2014) 151e154
colonized patients in a Brazilian hospital to characterize the lineages circulating within the institution.
Methods This observational study was performed between October 2005 and August 2006, at the Hospital Universita ´rio Clementino Fraga Filho (HUCFF), a tertiary-care public teaching hospital at Rio de Janeiro, Brazil with 490 beds and 1200 patients admitted per month. Nasal swabs were collected from all patients that met at least one of the following criteria: hospitalized in wards with a high MRSA incidence (more than four new cases per 1000 patient-days); hospitalized in the same room as a newly diagnosed MRSA patient; transferred from the intensive care unit of another hospital or had been submitted to invasive procedures at another hospital; undergoing haemodialysis; had previously been infected/colonized by MRSA; previously hospitalization in HUCFF; or had been submitted to solid organ transplantation. MRSA were identified using Clinical and Laboratory Standards Institute methodology: Staphylococcus aureus isolates were screened for MRSA using a cefoxitin disc (30 mg) (CECON, Sa ˜o Paulo, Brazil).6 All MRSA isolates were tested for 15 antimicrobials (Table I), SCCmec type, carriage of PVL genes and pulsed-field electrophoresis (PFGE).2,5 One isolate of each PFGE-defined genotype was typed by MLST.7 Minimum inhibitory concentration (MIC) to mupirocin was performed by the Etest (Biodisk, Solna, Sweden) in mupirocin-resistant isolates. Data were analysed using SPSS (version 16.0, SPSS Inc., Chicago, IL, USA). Statistical comparisons were performed by analysis of contingency tables using Fisher’s exact test; significance was established at 5% (P < 0.05).
Results Eighty-three MRSA-colonized patients were identified [internal medicine (IM), N ¼ 39; medical and surgical intensive care units (MSICU), N ¼ 15; infectious diseases (ID), N ¼ 10; dermatology, N ¼ 8; and others, N ¼ 11]. SCCmec III (43.4%) and IV (49.4%) were predominant. The SCCmec II and V were each found in three isolates (3.6%). Using standard interpretation criteria it was found that 34 pulsotypes belonged to 15 genotypes.2 ST1-IV (USA400) was the most common lineage (32.5%), followed by ST239-III (BEC) (27.7%). PVL genes were found in four type IV isolates: two ST1IV (USA400), one ST5-IV (USA800) and one ST97-IV.
Isolates from ST239-III were resistant to multiple classes of antimicrobial agents (Table I). By contrast, ST1-IV (USA400) isolates were commonly resistant to ciprofloxacin, clindamycin and erythromycin only. For the ST5-IV (USA800) isolates, rates of resistance to antimicrobial resistance did not exceed 50%, with the exception of erythromycin. The three ST5-IV (USA800) isolates resistant to mupirocin exhibited high-level resistance (MIC 1024 mg/L). Among 39 MRSA isolates from the IM wards, 56.4% had SCCmec IV and 91% of them were ST1 (USA400) (P ¼ 0.002), whereas for SCCmec III isolates, 68.7% were ST239 (BEC) (Table II). In the MSICU similar percentages of MRSA isolates carrying SCCmec types IV (46.6%) or III (46.6%) were found. The ‘M clone’ was significantly more common in MSICU when compared with the occurrence in other units (P ¼ 0.004). In the ID wards, most of the isolates carried SCCmec III and 71.4% of them belonged to ST239-III (BEC). SCCmec II isolates were detected mainly in ID wards and all were related to the ST5 (USA100). Moreover, SCCmec IV isolates were not found in the ID wards. In the dermatology wards, all isolates were ST5-IV (USA800) (P < 0.001).
Discussion To our knowledge, this is the first study to identify distinct MRSA lineages circulating in the major units of a general hospital in Brazil. SCCmec IV isolates accounted for the majority of the MRSA nasal isolates recovered in the main units of the hospital. This high proportion differed from studies carried out in some other countries. In the USA, Tenover et al. reported SCCmec type II as the most prevalent among nasal colonization isolates from different hospitals, whereas Luo et al. reported 77% of isolates were SCCmec III among colonized inpatients of an intensive care unit in a Chinese hospital.8,9 On the other hand, our data reflected the findings of MRSA isolates from infections in Brazil, where SCCmec IV isolates have emerged as the most common pathogen in hospitals.3,4 At the internal medicine wards, >90% of type IV isolates belonged to ST1 (USA400), a lineage already described as a significant cause of infections in Rio de Janeiro hospitals.3e5 Vivoni et al. identified circulating lineages of meticillinsusceptible S. aureus (MSSA) belonging to the ST1-IV (USA400) lineage in our hospital, between 1999 and 2004.2 It is possible that these isolates acquired SCCmec IV and have spread throughout the hospital. In the present study, two USA400 isolates were PVL positive; we believe this to be the first report
Table I Antimicrobial resistance to MRSA isolates belonging to the main lineages detected in a Brazilian teaching hospital, between October 2005 and August 2006 SCCmec type (no. of isolates) III (35) IV (33)
Clonality (no. of isolates) ST239 (BEC) (27) ‘M clone’ (8) ST1 (USA400) (22) ST5 (USA800) (11)
% Resistant Chl
Cip
Cli
Ery
Gen
Mup
Rif
Tmp/Stx
Tei
Tet
68.2 75.0 37.0 7.1
100 100 100 50.0
100 100 96.2 35.7
100 100 96.2 71.4
100 100 26.0 0
0 0 0 21.4
63.6 100 3.7 14.3
100 100 3.7 0
0 0 11.1 14.3
100 100 0 0
SCCmec, staphylococcal chromosome cassette mec; BEC, Brazilian epidemic clone; Chl, chloramphenicol; Cip, ciprofloxacin; Cli, clindamycin; Ery, erythromycin; Gen, gentamicin; Mup, mupirocin; Rif, rifampin; Tmp/Stx, trimethoprim/sulfamethoxazole; Tei, teicoplanin; Tet, tetracycline. All isolates were resistant to cefoxitin and penicillin G and susceptible to linezolid, tigecycline and vancomycin.
F.S. Cavalcante et al. / Journal of Hospital Infection 86 (2014) 151e154
153
Table II Types of SCCmec and clonality of 83 MRSA isolates recovered from patients in the main wards of a Brazilian teaching hospital, between October 2005 and August 2006 Hospital ward (no. of isolates) Internal medicine (39)
SCCmec types (no. of isolates)
Clonality (no. of isolates)
IV (22)
ST1 (USA400) (20) ST5 (USA800) (1) Other (1) ST239 (BEC) (11) ‘M clone’ (2) Othersc (3) Other (1) ST1 (USA400) (5) ST45 (USA600) (1) Other (1) ‘M clone’ (5) ST239 (BEC) (1) ST239 (Hungarian) (1) ST5 (USA100) (1) ST239 (BEC) (5) ‘M clone’ (1) Others (1) ST5 (USA100) (2) Other (1) ST5 (USA800) (8) ST1 (USA400) (2) ST5 (USA800) (2) ST239 (BEC) (6) Other (1)
III (16)
Medical and surgical intensive care units (15)
V (1) IV (7)
III (7)
Infectious diseases (10)
II (1) III (7)
Dermatology (8) Others (11)
II (2) V (1) IV (8) IV (4) III (6) V (1)
P-value 0.002a
0.19b
0.004d
0.005e
Journal of Hospital Infection journal homepage: www.elsevierhealth.com/journals/jhin
Short report
Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital F.S. Cavalcante a, R.P. Schuenck b, D.C. Ferreira a, ´r c, K.R.N. dos Santos a, * C.R. da Costa c, S.A. Noue a
Departamento de Microbiologia Me´dica, Instituto de Microbiologia Paulo de Go´es, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil b Departamento de Patologia, Universidade Federal do Espirito Santo, Espirito Santo, Brazil c Hospital Universita´rio Clementino Fraga Filho e Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
A R T I C L E
I N F O
Article history: Received 14 June 2013 Accepted 4 December 2013 Available online 21 December 2013 Keywords: Clonal complex Colonization Hospital wards Lineages Meticillin-resistant Staphylococcus aureus Staphylococcal cassette chromosome mec
S U M M A R Y
This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), PantoneValentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P ¼ 0.002) whereas ‘clone M’ (SCCmec III) was more common in the medical and surgical intensive care unit (P ¼ 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures. ª 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of healthcare-associated infections and some lineages are globally spread. Meticillin resistance is due to the * Corresponding author. Address: Laborato ¸˜ oes Hospital´rio de Infecc ares, Departamento de Microbiologia Me ´dica, Instituto de Microbiologia Paulo de Go ´es, Universidade Federal do Rio de Janeiro, CCS, Bloco I, Sala 010, Cidade Universita ´ria, CEP: 21941-590 Rio de Janeiro, RJ, Brazil. Tel.: þ55 21 2560 8344; fax: þ55 21 2560 8028. E-mail address: [email protected] (K.R.N. dos Santos).
mecA gene, located in a staphylococcal cassette chromosome (SCCmec); the most frequent types are I, II, III and IV.1 In Brazil, isolates related to the ‘Brazilian epidemic clone’ (BEC) multi-locus sequence type (ST) 239, SCCmec III (ST239-III) lineage were responsible for 90% of nosocomial MRSA isolates in the late 1990s.2 However, over the last decade SCCmec IV isolates have emerged in our country. Currently, ST1-IV (USA400) and ST5-IV (USA800) are the most common lineages identified in Brazilian hospitals.3e5 Studies characterizing isolates from nasal colonization of inpatients in Brazil have not been described. Here, we investigated the molecular characteristics of MRSA isolates from
0195-6701/$ e see front matter ª 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jhin.2013.12.004
152
F.S. Cavalcante et al. / Journal of Hospital Infection 86 (2014) 151e154
colonized patients in a Brazilian hospital to characterize the lineages circulating within the institution.
Methods This observational study was performed between October 2005 and August 2006, at the Hospital Universita ´rio Clementino Fraga Filho (HUCFF), a tertiary-care public teaching hospital at Rio de Janeiro, Brazil with 490 beds and 1200 patients admitted per month. Nasal swabs were collected from all patients that met at least one of the following criteria: hospitalized in wards with a high MRSA incidence (more than four new cases per 1000 patient-days); hospitalized in the same room as a newly diagnosed MRSA patient; transferred from the intensive care unit of another hospital or had been submitted to invasive procedures at another hospital; undergoing haemodialysis; had previously been infected/colonized by MRSA; previously hospitalization in HUCFF; or had been submitted to solid organ transplantation. MRSA were identified using Clinical and Laboratory Standards Institute methodology: Staphylococcus aureus isolates were screened for MRSA using a cefoxitin disc (30 mg) (CECON, Sa ˜o Paulo, Brazil).6 All MRSA isolates were tested for 15 antimicrobials (Table I), SCCmec type, carriage of PVL genes and pulsed-field electrophoresis (PFGE).2,5 One isolate of each PFGE-defined genotype was typed by MLST.7 Minimum inhibitory concentration (MIC) to mupirocin was performed by the Etest (Biodisk, Solna, Sweden) in mupirocin-resistant isolates. Data were analysed using SPSS (version 16.0, SPSS Inc., Chicago, IL, USA). Statistical comparisons were performed by analysis of contingency tables using Fisher’s exact test; significance was established at 5% (P < 0.05).
Results Eighty-three MRSA-colonized patients were identified [internal medicine (IM), N ¼ 39; medical and surgical intensive care units (MSICU), N ¼ 15; infectious diseases (ID), N ¼ 10; dermatology, N ¼ 8; and others, N ¼ 11]. SCCmec III (43.4%) and IV (49.4%) were predominant. The SCCmec II and V were each found in three isolates (3.6%). Using standard interpretation criteria it was found that 34 pulsotypes belonged to 15 genotypes.2 ST1-IV (USA400) was the most common lineage (32.5%), followed by ST239-III (BEC) (27.7%). PVL genes were found in four type IV isolates: two ST1IV (USA400), one ST5-IV (USA800) and one ST97-IV.
Isolates from ST239-III were resistant to multiple classes of antimicrobial agents (Table I). By contrast, ST1-IV (USA400) isolates were commonly resistant to ciprofloxacin, clindamycin and erythromycin only. For the ST5-IV (USA800) isolates, rates of resistance to antimicrobial resistance did not exceed 50%, with the exception of erythromycin. The three ST5-IV (USA800) isolates resistant to mupirocin exhibited high-level resistance (MIC 1024 mg/L). Among 39 MRSA isolates from the IM wards, 56.4% had SCCmec IV and 91% of them were ST1 (USA400) (P ¼ 0.002), whereas for SCCmec III isolates, 68.7% were ST239 (BEC) (Table II). In the MSICU similar percentages of MRSA isolates carrying SCCmec types IV (46.6%) or III (46.6%) were found. The ‘M clone’ was significantly more common in MSICU when compared with the occurrence in other units (P ¼ 0.004). In the ID wards, most of the isolates carried SCCmec III and 71.4% of them belonged to ST239-III (BEC). SCCmec II isolates were detected mainly in ID wards and all were related to the ST5 (USA100). Moreover, SCCmec IV isolates were not found in the ID wards. In the dermatology wards, all isolates were ST5-IV (USA800) (P < 0.001).
Discussion To our knowledge, this is the first study to identify distinct MRSA lineages circulating in the major units of a general hospital in Brazil. SCCmec IV isolates accounted for the majority of the MRSA nasal isolates recovered in the main units of the hospital. This high proportion differed from studies carried out in some other countries. In the USA, Tenover et al. reported SCCmec type II as the most prevalent among nasal colonization isolates from different hospitals, whereas Luo et al. reported 77% of isolates were SCCmec III among colonized inpatients of an intensive care unit in a Chinese hospital.8,9 On the other hand, our data reflected the findings of MRSA isolates from infections in Brazil, where SCCmec IV isolates have emerged as the most common pathogen in hospitals.3,4 At the internal medicine wards, >90% of type IV isolates belonged to ST1 (USA400), a lineage already described as a significant cause of infections in Rio de Janeiro hospitals.3e5 Vivoni et al. identified circulating lineages of meticillinsusceptible S. aureus (MSSA) belonging to the ST1-IV (USA400) lineage in our hospital, between 1999 and 2004.2 It is possible that these isolates acquired SCCmec IV and have spread throughout the hospital. In the present study, two USA400 isolates were PVL positive; we believe this to be the first report
Table I Antimicrobial resistance to MRSA isolates belonging to the main lineages detected in a Brazilian teaching hospital, between October 2005 and August 2006 SCCmec type (no. of isolates) III (35) IV (33)
Clonality (no. of isolates) ST239 (BEC) (27) ‘M clone’ (8) ST1 (USA400) (22) ST5 (USA800) (11)
% Resistant Chl
Cip
Cli
Ery
Gen
Mup
Rif
Tmp/Stx
Tei
Tet
68.2 75.0 37.0 7.1
100 100 100 50.0
100 100 96.2 35.7
100 100 96.2 71.4
100 100 26.0 0
0 0 0 21.4
63.6 100 3.7 14.3
100 100 3.7 0
0 0 11.1 14.3
100 100 0 0
SCCmec, staphylococcal chromosome cassette mec; BEC, Brazilian epidemic clone; Chl, chloramphenicol; Cip, ciprofloxacin; Cli, clindamycin; Ery, erythromycin; Gen, gentamicin; Mup, mupirocin; Rif, rifampin; Tmp/Stx, trimethoprim/sulfamethoxazole; Tei, teicoplanin; Tet, tetracycline. All isolates were resistant to cefoxitin and penicillin G and susceptible to linezolid, tigecycline and vancomycin.
F.S. Cavalcante et al. / Journal of Hospital Infection 86 (2014) 151e154
153
Table II Types of SCCmec and clonality of 83 MRSA isolates recovered from patients in the main wards of a Brazilian teaching hospital, between October 2005 and August 2006 Hospital ward (no. of isolates) Internal medicine (39)
SCCmec types (no. of isolates)
Clonality (no. of isolates)
IV (22)
ST1 (USA400) (20) ST5 (USA800) (1) Other (1) ST239 (BEC) (11) ‘M clone’ (2) Othersc (3) Other (1) ST1 (USA400) (5) ST45 (USA600) (1) Other (1) ‘M clone’ (5) ST239 (BEC) (1) ST239 (Hungarian) (1) ST5 (USA100) (1) ST239 (BEC) (5) ‘M clone’ (1) Others (1) ST5 (USA100) (2) Other (1) ST5 (USA800) (8) ST1 (USA400) (2) ST5 (USA800) (2) ST239 (BEC) (6) Other (1)
III (16)
Medical and surgical intensive care units (15)
V (1) IV (7)
III (7)
Infectious diseases (10)
II (1) III (7)
Dermatology (8) Others (11)
II (2) V (1) IV (8) IV (4) III (6) V (1)
P-value 0.002a
0.19b
0.004d
0.005e
