American Journal of Infection Control xxx (2015) 1-4
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Risk factors for extensive drug-resistance and mortality in geriatric inpatients with bacteremia caused by Acinetobacter baumannii Qiang Fu MM a, Huan Ye MD a, *, Shumei Liu MM b a b
Department of Infectious Diseases, FuXing Hospital, Capital Medical University, Beijing, PR China Department of Microbiology and Clinical Laboratory, FuXing Hospital, Capital Medical University, Beijing, PR China
Key Words: Acinetobacter baumannii Bacteremia Extensive drug resistance Risk factors Geriatric inpatients
Background: The aim of this study was to explore the risk factors for developing bacteremia caused by extensive drug-resistant (XDR) Acinetobacter baumannii and the associated mortality in geriatric inpatients. Methods: We conducted a retrospective study of 125 patients with A baumannii bacteremia between October 2008 and December 2013 at a medical center in China. Results: The 30-day hospital mortality rate was 55.2%. XDR A baumannii was detected in 31.2% of all cases. A logistic regression analysis suggested that chronic obstructive pulmonary disease, a bedridden status, and central venous catheters were associated with bacteremia caused by XDR A baumannii, with adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of 2.59 (1.01-6.64), 4.08 (1.39-12.01), and 9.52 (1.90-47.56), respectively. Furthermore, intensive care unit (ICU) stay, bacteremia caused by XDR A baumannii, concurrent fungal infection, and age (70-80 years old and >80 years old) were associated with mortality, with aORs and 95% CIs of 3.16 (1.29-7.73), 4.01 (1.46-11.04), 3.20 (1.28-7.98), 4.31 (1.44-12.92), and 5.46 (1.94-15.35), respectively. Conclusion: Bacteremia is associated with a high 30-day hospital mortality rate in geriatric inpatients. Furthermore, ICU stay, bacteremia caused by XDR A baumannii, concurrent fungal infection, and age are associated with increased mortality in geriatric inpatients with A baumannii bacteremia. Copyright Ó 2015 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Bacteremia caused by Acinetobacter baumannii is a common nosocomial infection in critically ill patients. Acinetobacter spp consist of nonfermenting gram-negative coccobacilli that are often associated with health care environments, and they are opportunistic pathogens.1 Although initially considered to possess a low pathogenic potential in healthy individuals, A baumannii is now largely regarded as one of the most troublesome pathogens and is responsible for several types of nosocomial infections.2,3 In particular, A baumannii has emerged as an important nosocomial pathogen responsible for bacteremia.2,4 A large amount of information is available regarding the epidemiology, risk factors, and outcomes of patients with A baumannii bacteremia. Recent research has demonstrated that bacteremia caused by multidrug-resistant (MDR) and carbapenemresistant (CR) A baumannii typically leads to increased mortality
and prolonged hospital stays.4-9 However, information is limited regarding the clinical outcomes and risk factors for extensive drugresistant (XDR) A baumannii bacteremia and the associated mortality rates in geriatric inpatients in developing countries. Therefore, the present retrospective study investigated the risk factors for bloodstream infections caused by XDR A baumannii in geriatric inpatients. We also analyzed the clinical characteristics and outcomes of A baumannii bacteremia. All of the patients were evaluated at Fu Xing Hospital, Capital Medical University (FXH-CMU). FXH-CMU is a 705-bed, universityaffiliated teaching hospital that has successfully implemented a 2way referral system with several community health service centers in Beijing, China.
* Address correspondence to Huan Ye, PhD, Department of Infectious Diseases, FuXing Hospital, Capital Medical University, 20A Fu Xing Men Wai Da Jie, Xicheng District, Beijing 100038, PR China. E-mail address: [email protected] (H. Ye). Conflicts of interest: None to report.
Study participants
MATERIALS AND METHODS
This study retrospectively reviewed data that were prospectively and routinely collected for geriatric inpatients (aged
0196-6553/$36.00 - Copyright Ó 2015 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.2015.03.033
2
Q. Fu et al. / American Journal of Infection Control xxx (2015) 1-4
>65 years) with demonstrated A baumannii bacteremia who were receiving care at FXH-CMU between October 2008 and December 2013. The cases were reviewed in the FXH-CMU microbiology and inspection laboratory database by searching for at least 2 positive blood cultures. The medical records of the cases were obtained from the medical record archives. The demographics, information regarding clinical care, microbiologic data, treatments provided, and outcomes of the patients with clinically significant A baumannii bacteremia were reviewed. Ethical approval This study was approved by the Ethics Committee of FXH-CMU. Definitions Significant bacteremia was defined as the isolation of A baumannii from 1 blood culture specimen and the presence of clinical features consistent with infection (eg, fever, leukocytosis). Nosocomial bacteremia was defined as the isolation of 1 A baumannii isolate from blood culture at 48 hours after admission. Standard microbiologic methods were used to isolate and identify A baumannii from blood specimens. Blood specimens were cultured using the BACTEC FX2000 blood culture system (Becton, Dickinson and Co, Franklin Lakes, NJ). Polymyxin susceptibility was not a part of routine susceptibility testing at our hospital because the Sensi-Disc (Bio Mérieux SA, Marcy l‘Etoile, France) was not available. Bacterial isolation and antimicrobial susceptibility testing were performed in accordance with the methodology of the Clinical and Laboratory Standards Institute.10 The designation of MDR was defined as the absence of susceptibility to 3 of the following antimicrobials or groups of antimicrobials: aminoglycosides, antipseudomonal penicillin and b-lactamase inhibitor combinations, antipseudomonal carbapenems, antipseudomonal fluoroquinolones, trimethoprimsulfamethoxazole, cephalosporins, ampicillin-sulbactam, polymyxins, or tetracyclines. The designation of XDR was defined as the absence of susceptibility to all of the mentioned antimicrobials, excluding polymyxins and tigecycline.11 The designation of CR was defined as in vitro resistance to imipenem or meropenem. Bedridden status was defined according to the Residential Care Facilities for the Elderly 2009 criteria as duration in bed of >14 days with no possibility of recovery. Statistical analysis All of the statistical analyses were performed using SPSS 13.0 (SPSS, Chicago, IL). All of the P values were 2 tailed, and P < .05 was considered statistically significant. Continuous variables were generally presented as means and SDs. Categorical variables were expressed as percentages. Continuous variables were compared using Student t test or Mann-Whitney U test. Categorical variables were compared with the c2 test or Fisher exact test when the expected values were 80 APACHE II score 20 Origin of patients Medical Surgery Bedridden Comorbidities Cerebrovascular diseases Diabetes mellitus COPD Malignancy ESRD Prior invasive procedures Mechanical ventilation Central venous catheters Source of bacteremia Vascular catheter Respiratory tract Other source Concurrent fungal infection Enteric dysbacteriosis Prior use of broad-spectrum antibiotics ICU stay Duration of stay in the hospital, d 30-d hospital mortality
XDRAB (N ¼ 39)
Non-XDRAB (N ¼ 86)
26 (66.7)
49 (57.0)
7 10 22 24
22 30 34 41
(17.9) (25.6) (56.4) (61.5)
(25.6) (34.9) (39.5) (47.7)
P value .31 .21
.15 .18
27 (69.2) 12 (30.8) 15 (38.5)
69 (80.2) 17 (19.8) 14 (16.3)
.01
28 16 20 10 11
64 29 22 24 15
(74.4) (33.7) (25.6) (27.9) (17.4)
.76 .43 .01 .79 .17
36 (92.3) 37 (94.9)
49 (57.0) 47 (54.7)
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Risk factors for extensive drug-resistance and mortality in geriatric inpatients with bacteremia caused by Acinetobacter baumannii Qiang Fu MM a, Huan Ye MD a, *, Shumei Liu MM b a b
Department of Infectious Diseases, FuXing Hospital, Capital Medical University, Beijing, PR China Department of Microbiology and Clinical Laboratory, FuXing Hospital, Capital Medical University, Beijing, PR China
Key Words: Acinetobacter baumannii Bacteremia Extensive drug resistance Risk factors Geriatric inpatients
Background: The aim of this study was to explore the risk factors for developing bacteremia caused by extensive drug-resistant (XDR) Acinetobacter baumannii and the associated mortality in geriatric inpatients. Methods: We conducted a retrospective study of 125 patients with A baumannii bacteremia between October 2008 and December 2013 at a medical center in China. Results: The 30-day hospital mortality rate was 55.2%. XDR A baumannii was detected in 31.2% of all cases. A logistic regression analysis suggested that chronic obstructive pulmonary disease, a bedridden status, and central venous catheters were associated with bacteremia caused by XDR A baumannii, with adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of 2.59 (1.01-6.64), 4.08 (1.39-12.01), and 9.52 (1.90-47.56), respectively. Furthermore, intensive care unit (ICU) stay, bacteremia caused by XDR A baumannii, concurrent fungal infection, and age (70-80 years old and >80 years old) were associated with mortality, with aORs and 95% CIs of 3.16 (1.29-7.73), 4.01 (1.46-11.04), 3.20 (1.28-7.98), 4.31 (1.44-12.92), and 5.46 (1.94-15.35), respectively. Conclusion: Bacteremia is associated with a high 30-day hospital mortality rate in geriatric inpatients. Furthermore, ICU stay, bacteremia caused by XDR A baumannii, concurrent fungal infection, and age are associated with increased mortality in geriatric inpatients with A baumannii bacteremia. Copyright Ó 2015 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Bacteremia caused by Acinetobacter baumannii is a common nosocomial infection in critically ill patients. Acinetobacter spp consist of nonfermenting gram-negative coccobacilli that are often associated with health care environments, and they are opportunistic pathogens.1 Although initially considered to possess a low pathogenic potential in healthy individuals, A baumannii is now largely regarded as one of the most troublesome pathogens and is responsible for several types of nosocomial infections.2,3 In particular, A baumannii has emerged as an important nosocomial pathogen responsible for bacteremia.2,4 A large amount of information is available regarding the epidemiology, risk factors, and outcomes of patients with A baumannii bacteremia. Recent research has demonstrated that bacteremia caused by multidrug-resistant (MDR) and carbapenemresistant (CR) A baumannii typically leads to increased mortality
and prolonged hospital stays.4-9 However, information is limited regarding the clinical outcomes and risk factors for extensive drugresistant (XDR) A baumannii bacteremia and the associated mortality rates in geriatric inpatients in developing countries. Therefore, the present retrospective study investigated the risk factors for bloodstream infections caused by XDR A baumannii in geriatric inpatients. We also analyzed the clinical characteristics and outcomes of A baumannii bacteremia. All of the patients were evaluated at Fu Xing Hospital, Capital Medical University (FXH-CMU). FXH-CMU is a 705-bed, universityaffiliated teaching hospital that has successfully implemented a 2way referral system with several community health service centers in Beijing, China.
* Address correspondence to Huan Ye, PhD, Department of Infectious Diseases, FuXing Hospital, Capital Medical University, 20A Fu Xing Men Wai Da Jie, Xicheng District, Beijing 100038, PR China. E-mail address: [email protected] (H. Ye). Conflicts of interest: None to report.
Study participants
MATERIALS AND METHODS
This study retrospectively reviewed data that were prospectively and routinely collected for geriatric inpatients (aged
0196-6553/$36.00 - Copyright Ó 2015 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.2015.03.033
2
Q. Fu et al. / American Journal of Infection Control xxx (2015) 1-4
>65 years) with demonstrated A baumannii bacteremia who were receiving care at FXH-CMU between October 2008 and December 2013. The cases were reviewed in the FXH-CMU microbiology and inspection laboratory database by searching for at least 2 positive blood cultures. The medical records of the cases were obtained from the medical record archives. The demographics, information regarding clinical care, microbiologic data, treatments provided, and outcomes of the patients with clinically significant A baumannii bacteremia were reviewed. Ethical approval This study was approved by the Ethics Committee of FXH-CMU. Definitions Significant bacteremia was defined as the isolation of A baumannii from 1 blood culture specimen and the presence of clinical features consistent with infection (eg, fever, leukocytosis). Nosocomial bacteremia was defined as the isolation of 1 A baumannii isolate from blood culture at 48 hours after admission. Standard microbiologic methods were used to isolate and identify A baumannii from blood specimens. Blood specimens were cultured using the BACTEC FX2000 blood culture system (Becton, Dickinson and Co, Franklin Lakes, NJ). Polymyxin susceptibility was not a part of routine susceptibility testing at our hospital because the Sensi-Disc (Bio Mérieux SA, Marcy l‘Etoile, France) was not available. Bacterial isolation and antimicrobial susceptibility testing were performed in accordance with the methodology of the Clinical and Laboratory Standards Institute.10 The designation of MDR was defined as the absence of susceptibility to 3 of the following antimicrobials or groups of antimicrobials: aminoglycosides, antipseudomonal penicillin and b-lactamase inhibitor combinations, antipseudomonal carbapenems, antipseudomonal fluoroquinolones, trimethoprimsulfamethoxazole, cephalosporins, ampicillin-sulbactam, polymyxins, or tetracyclines. The designation of XDR was defined as the absence of susceptibility to all of the mentioned antimicrobials, excluding polymyxins and tigecycline.11 The designation of CR was defined as in vitro resistance to imipenem or meropenem. Bedridden status was defined according to the Residential Care Facilities for the Elderly 2009 criteria as duration in bed of >14 days with no possibility of recovery. Statistical analysis All of the statistical analyses were performed using SPSS 13.0 (SPSS, Chicago, IL). All of the P values were 2 tailed, and P < .05 was considered statistically significant. Continuous variables were generally presented as means and SDs. Categorical variables were expressed as percentages. Continuous variables were compared using Student t test or Mann-Whitney U test. Categorical variables were compared with the c2 test or Fisher exact test when the expected values were 80 APACHE II score 20 Origin of patients Medical Surgery Bedridden Comorbidities Cerebrovascular diseases Diabetes mellitus COPD Malignancy ESRD Prior invasive procedures Mechanical ventilation Central venous catheters Source of bacteremia Vascular catheter Respiratory tract Other source Concurrent fungal infection Enteric dysbacteriosis Prior use of broad-spectrum antibiotics ICU stay Duration of stay in the hospital, d 30-d hospital mortality
XDRAB (N ¼ 39)
Non-XDRAB (N ¼ 86)
26 (66.7)
49 (57.0)
7 10 22 24
22 30 34 41
(17.9) (25.6) (56.4) (61.5)
(25.6) (34.9) (39.5) (47.7)
P value .31 .21
.15 .18
27 (69.2) 12 (30.8) 15 (38.5)
69 (80.2) 17 (19.8) 14 (16.3)
.01
28 16 20 10 11
64 29 22 24 15
(74.4) (33.7) (25.6) (27.9) (17.4)
.76 .43 .01 .79 .17
36 (92.3) 37 (94.9)
49 (57.0) 47 (54.7)
