American Journal of Infection Control 42 (2014) 1340-2
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Brief report
Antimicrobial susceptibility profiles of Staphylococcus aureus isolates classified according to their origin in a tertiary hospital in Korea Hee-Won Moon MD, PhD *, Hyun Jung Kim MD, Mina Hur MD, PhD, Yeo-Min Yun MD, PhD Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea
Key Words: Staphylococcus aureus Community-associated methicillin-resistant Staphylococcus aureus Korea Antimicrobial susceptibility
We performed a comprehensive analysis on 3,594 Staphylococcus aureus isolates from routine culture during the last 4 years. The antimicrobial susceptibilities of the isolates were analyzed according to their origin and were compared based on the type of specimens. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in community-associated (CA), health careeassociated, community onset (HACO), and health careeassociated (HA) isolates were 33.0%, 54.3%, and 73.3%, respectively. The MRSA rate differed significantly between specimens, with the highest rate from urine in the CA and HACO isolates, whereas the highest rate from the respiratory tract was in the HA isolates. The monitoring of the MRSA rate in CA, HACO, and HA S aureus isolates would be valuable for surveillance. The elevated rates of MRSA in urinary specimens from CA and HCA isolates need to be addressed for infection control. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Methicillin-resistant Staphylococcus aureus (MRSA) is a wellknown representative, nosocomial pathogen in patients; however, the epidemiology of MRSA has changed because of the emergence of community-associated (CA) MRSA.1-3 In this study, we performed a comprehensive analysis of all S aureus isolates obtained during the last 4 years (2010-2013) in a tertiary hospital in Korea. Antimicrobial susceptibility of the isolates was analyzed according to their origin (CA and health care associated [HA]) and was compared based on the type of specimen they were isolated from, which was rarely performed in previous studies. METHODS The study protocol was approved by the institutional review boards of Konkuk University Medical Center. We performed a retrospective study using data from laboratory and hospital databases at a tertiary university hospital with approximately 900 beds in Seoul, South Korea, between January 2010 and December 2013. Of the nonduplicate 3,594 S aureus isolates, 1,802 (50.1%) were isolated from patients whose clinical cultures were obtained >48 hours after admission and defined as HA. The 852 isolates * Address correspondence to Hee-Won Moon, MD, PhD, Department of Laboratory Medicine, Konkuk University Hospital, Konkuk University School of Medicine, Neungdong-ro, Gwangjin-gu, Seoul 120-1, South Korea. E-mail address: [email protected] (H.-W. Moon). Funding/support: This study was supported by Konkuk University. Conflicts of interest: None to report.
(23.7%), which were isolated 48 hours after admission or from an outpatient clinic (community onset) and without any established health careerelated risk factors (HRFs), were defined as CA isolates.3,4 The remaining 940 isolates (26.2%) from patients with HRFs were defined as health care associated, community onset (HACO).4 The patients from whom CA cultures were isolated showed significantly lower mean age than those of HACO and HA isolates (48, 59, and 60 years old, respectively; P < .001) and less male proportion (52.5%, 58.4%, and 58.5%, respectively; P ¼ .009). Bacterial identification and antimicrobial susceptibility were performed using the VITEK 2 System (bioMérieux, Marcy l’Etoile, France) based on the current guidelines of the Clinical and Laboratory Standards Institute.5 RESULTS The proportions of MRSA in CA, HACO, and HA isolates were 33.0%, 54.3%, and 73.3%, respectively, differing significantly between the isolates of different origins (Table 1). Of the 2,112 MRSA isolates, 281 (13.3%) were classified as CA MRSA. The resistance rates toward most antimicrobial agents were significantly different between the CA, HACO, and HA groups (P < .001). The MRSA rates in isolates obtained from various specimen types were significantly different (P < .001 for CA and HACO isolates, P < .023 for HA isolates) (Table 2). A pronounced difference in the MRSA rate was observed in the CA isolates; the highest rate was observed in isolates obtained from urine specimens (61.9%). The mean age of patients who had CA MRSA isolates in urine was
0196-6553/$36.00 - Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajic.2014.08.014
H.-W. Moon et al. / American Journal of Infection Control 42 (2014) 1340-2 Table 1 Antimicrobial resistance (%) of Staphylococcus aureus according to type of origin Antibiotics
CA (n ¼ 852)
HACO (n ¼ 940)
HA (n ¼ 1,802)
33.0 29.3 15.1 31.6 24.8 17.7 0.1 0.0 2.7 90.7 0.0 0.9 1.3 13.5 17.5 0.0 0.0 0.0
54.3 46.5 37.2 47.9 40.4 31.5 0.1 0.0 3.2 93.6 0.0 2.9 1.9 31.1 35.2 0.0 0.0 0.0
73.3 65.4 56.2 66.5 53.3 46.7 0.0 0.0 3.7 96.0 0.0 5.2 2.0 53.3 55.1 0.0 0.0 0.0
Oxacillin* Clindamycin* Ciprofloxacin* Erythromycin* Fusidic acid* Gentamicin* Habekacin Linezolid Mupirocin Benzylpenicillin* Quinupristin-dalfopristin Rifampin* Trimethoprim-sulfamethoxazole Telithromycin* Tetracycline* Tigecycline Teicoplanin Vancomycin
CA, community associated; HA, health care associated; HACO, health care associated, community onset. *P < .001 by c2 test.
Table 2 Proportion (%) of MRSA according to specimens and type of origin Specimens Skin and soft tissue Blood and fluid Respiratory tract Ear discharge Joint Deep site tissue Genital tract Urine Nasal swab
CA* 26.6 28.6 30.8 40.0 25.0 33.3 38.5 61.9 8.6
(53/199) (10/35) (97/315) (66/165) (3/12) (5/15) (5/13) (39/63) (3/35)
HAy
HACO* 46.0 49.3 60.8 44.0 20.0 47.6 50.0 75.0 33.3
(125/272) (69/140) (244/401) (9/20) (2/10) (10/21) (2/4) (45/60) (4/12)
70.2 72.0 75.2 57.1 66.7 33.3 NA 71.6 58.3
(228/325) (154/214) (874/1,162) (4/7) (2/3) (4/12) (48/67) (7/12)
CA, community associated; HA, health care associated; HACO, health care associated, community onset; MRSA, methicillin-resistant Staphylococcus aureus; NA, not applicable. *P < .001 between specimens by c2 test. y P < .023 between specimens by c2 test.
significantly lower than those of other specimens (13 years old in urine vs 34 and 46 years old in skin and soft tissues and ear discharge, respectively). Most of them (82.1%, 32/39) were
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Brief report
Antimicrobial susceptibility profiles of Staphylococcus aureus isolates classified according to their origin in a tertiary hospital in Korea Hee-Won Moon MD, PhD *, Hyun Jung Kim MD, Mina Hur MD, PhD, Yeo-Min Yun MD, PhD Department of Laboratory Medicine, Konkuk University School of Medicine, Seoul, Republic of Korea
Key Words: Staphylococcus aureus Community-associated methicillin-resistant Staphylococcus aureus Korea Antimicrobial susceptibility
We performed a comprehensive analysis on 3,594 Staphylococcus aureus isolates from routine culture during the last 4 years. The antimicrobial susceptibilities of the isolates were analyzed according to their origin and were compared based on the type of specimens. The proportion of methicillin-resistant Staphylococcus aureus (MRSA) in community-associated (CA), health careeassociated, community onset (HACO), and health careeassociated (HA) isolates were 33.0%, 54.3%, and 73.3%, respectively. The MRSA rate differed significantly between specimens, with the highest rate from urine in the CA and HACO isolates, whereas the highest rate from the respiratory tract was in the HA isolates. The monitoring of the MRSA rate in CA, HACO, and HA S aureus isolates would be valuable for surveillance. The elevated rates of MRSA in urinary specimens from CA and HCA isolates need to be addressed for infection control. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Methicillin-resistant Staphylococcus aureus (MRSA) is a wellknown representative, nosocomial pathogen in patients; however, the epidemiology of MRSA has changed because of the emergence of community-associated (CA) MRSA.1-3 In this study, we performed a comprehensive analysis of all S aureus isolates obtained during the last 4 years (2010-2013) in a tertiary hospital in Korea. Antimicrobial susceptibility of the isolates was analyzed according to their origin (CA and health care associated [HA]) and was compared based on the type of specimen they were isolated from, which was rarely performed in previous studies. METHODS The study protocol was approved by the institutional review boards of Konkuk University Medical Center. We performed a retrospective study using data from laboratory and hospital databases at a tertiary university hospital with approximately 900 beds in Seoul, South Korea, between January 2010 and December 2013. Of the nonduplicate 3,594 S aureus isolates, 1,802 (50.1%) were isolated from patients whose clinical cultures were obtained >48 hours after admission and defined as HA. The 852 isolates * Address correspondence to Hee-Won Moon, MD, PhD, Department of Laboratory Medicine, Konkuk University Hospital, Konkuk University School of Medicine, Neungdong-ro, Gwangjin-gu, Seoul 120-1, South Korea. E-mail address: [email protected] (H.-W. Moon). Funding/support: This study was supported by Konkuk University. Conflicts of interest: None to report.
(23.7%), which were isolated 48 hours after admission or from an outpatient clinic (community onset) and without any established health careerelated risk factors (HRFs), were defined as CA isolates.3,4 The remaining 940 isolates (26.2%) from patients with HRFs were defined as health care associated, community onset (HACO).4 The patients from whom CA cultures were isolated showed significantly lower mean age than those of HACO and HA isolates (48, 59, and 60 years old, respectively; P < .001) and less male proportion (52.5%, 58.4%, and 58.5%, respectively; P ¼ .009). Bacterial identification and antimicrobial susceptibility were performed using the VITEK 2 System (bioMérieux, Marcy l’Etoile, France) based on the current guidelines of the Clinical and Laboratory Standards Institute.5 RESULTS The proportions of MRSA in CA, HACO, and HA isolates were 33.0%, 54.3%, and 73.3%, respectively, differing significantly between the isolates of different origins (Table 1). Of the 2,112 MRSA isolates, 281 (13.3%) were classified as CA MRSA. The resistance rates toward most antimicrobial agents were significantly different between the CA, HACO, and HA groups (P < .001). The MRSA rates in isolates obtained from various specimen types were significantly different (P < .001 for CA and HACO isolates, P < .023 for HA isolates) (Table 2). A pronounced difference in the MRSA rate was observed in the CA isolates; the highest rate was observed in isolates obtained from urine specimens (61.9%). The mean age of patients who had CA MRSA isolates in urine was
0196-6553/$36.00 - Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajic.2014.08.014
H.-W. Moon et al. / American Journal of Infection Control 42 (2014) 1340-2 Table 1 Antimicrobial resistance (%) of Staphylococcus aureus according to type of origin Antibiotics
CA (n ¼ 852)
HACO (n ¼ 940)
HA (n ¼ 1,802)
33.0 29.3 15.1 31.6 24.8 17.7 0.1 0.0 2.7 90.7 0.0 0.9 1.3 13.5 17.5 0.0 0.0 0.0
54.3 46.5 37.2 47.9 40.4 31.5 0.1 0.0 3.2 93.6 0.0 2.9 1.9 31.1 35.2 0.0 0.0 0.0
73.3 65.4 56.2 66.5 53.3 46.7 0.0 0.0 3.7 96.0 0.0 5.2 2.0 53.3 55.1 0.0 0.0 0.0
Oxacillin* Clindamycin* Ciprofloxacin* Erythromycin* Fusidic acid* Gentamicin* Habekacin Linezolid Mupirocin Benzylpenicillin* Quinupristin-dalfopristin Rifampin* Trimethoprim-sulfamethoxazole Telithromycin* Tetracycline* Tigecycline Teicoplanin Vancomycin
CA, community associated; HA, health care associated; HACO, health care associated, community onset. *P < .001 by c2 test.
Table 2 Proportion (%) of MRSA according to specimens and type of origin Specimens Skin and soft tissue Blood and fluid Respiratory tract Ear discharge Joint Deep site tissue Genital tract Urine Nasal swab
CA* 26.6 28.6 30.8 40.0 25.0 33.3 38.5 61.9 8.6
(53/199) (10/35) (97/315) (66/165) (3/12) (5/15) (5/13) (39/63) (3/35)
HAy
HACO* 46.0 49.3 60.8 44.0 20.0 47.6 50.0 75.0 33.3
(125/272) (69/140) (244/401) (9/20) (2/10) (10/21) (2/4) (45/60) (4/12)
70.2 72.0 75.2 57.1 66.7 33.3 NA 71.6 58.3
(228/325) (154/214) (874/1,162) (4/7) (2/3) (4/12) (48/67) (7/12)
CA, community associated; HA, health care associated; HACO, health care associated, community onset; MRSA, methicillin-resistant Staphylococcus aureus; NA, not applicable. *P < .001 between specimens by c2 test. y P < .023 between specimens by c2 test.
significantly lower than those of other specimens (13 years old in urine vs 34 and 46 years old in skin and soft tissues and ear discharge, respectively). Most of them (82.1%, 32/39) were
