Retrospective Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. May 26, 2019; 7(10): 1111-1121
Published online May 26, 2019. doi: 10.12998/wjcc.v7.i10.1111
Risk factors and clinical responses of pneumonia patients with colistin-resistant Acinetobacter baumannii-calcoaceticus
Hande Aydemir, Hande Idil Tuz, Nihal Piskin, Guven Celebi, Canan Kulah, Furuzan Kokturk
Hande Aydemir, Hande Idil Tuz, Nihal Piskin, Guven Celebi, Department of Infectious Diseases and Clinical Microbiology, Zonguldak Bulent Ecevit University, Faculty of Medicine, Zonguldak 67100, Turkey
Canan Kulah, Department of Microbiology, Zonguldak Bulent Ecevit University, Faculty of Medicine, Zonguldak 67100, Turkey
Furuzan Kokturk, Department of Biostatistics, Zonguldak Bulent Ecevit University, Faculty of Medicine, Zonguldak 67100, Turkey
Author contributions: Aydemir H and Tuz HI contributed together to this work; Aydemir H, Piskin N and Celebi G designed research; Aydemir H, Tuz HI and Kulah C performed research; Kokturk F analyzed data; and Aydemir H wrote the paper.
Institutional review board statement: This study was approved by the ethics committee of Zonguldak Bulent Ecevit University Teaching and Research Hospital.
Informed consent statement: Patients were not required to give informed consent statement for this study due to the suggestion of ethical committee of our hospital. We did not use any personal data. The data which was used for this study is available from our hospital’s computer system. But written informed consent forms were taken for the agreement to treatment of pan-drug resistant Acinetobacter baumannii infections from patients or legal representatives.
Conflict-of-interest statement: All authors declare no conflicts of interest related to this article.
Data sharing statement: The datasets used and/or analyzed during this study available from the corresponding author on reasonable request.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Hande Aydemir, MD, Associate Professor, Department of Infectious Diseases and Clinical Microbiology, Zonguldak Bulent Ecevit University, Faculty of Medicine, Bülent Ecevit Üniversitesi Tıp fakültesi, Enfeksiyon hastalıkları A. D, Zonguldak 67100, Turkey. drhaydemir@yahoo.com
Telephone: +90-538-3712756 Fax: +90-372-2610264
Received: February 10, 2019
Peer-review started: February 12, 2019
First decision: April 18, 2019
Revised: April 24, 2019
Accepted: May 1, 2019
Article in press: May 1, 2019
Published online: May 26, 2019
Processing time: 108 Days and 18.7 Hours
Abstract
BACKGROUND

Nosocomial infections with carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (ABC) strains are great problem for intensive care units. ABC strains can develop resistance to all the antibiotics available. Carbapenem resistance is common and colistin resistance is rare in our country. Knowing the risk factors for colistin resistance is important since colistin seems to be the only remaining therapeutic option for the patients with pneumonia due to extensively drug resistant ABC for our country.

AIM

To investigate the comparison of clinical responses and outcomes between pneumonia patients with colistin-susceptible and -resistant Acinetobacter sp. Strains.

METHODS

During the study period, 108 patients with pneumonia due to colistin-susceptible strains and 16 patients with colistin-resistant strains were included retrospectively. Continuous variables were compared with the Mann-Whitney U test, and categorical variables were compared using Pearson’s chi-square test or Fisher’s Exact chi-square test for two groups. A binary logistic regression model was developed to identify the potential independent factors associated with colistin resistance in patients with colistin-resistant strains.

RESULTS

High Acute Physiology and Chronic Health Evaluation II scores (OR = 1.9, 95%CI: 1.4-2.7; P < 0.001) and prior receipt of teicoplanin (OR = 8.1, 95%CI: 1.0-63.3; P = 0.045) were found to be independent risk factors for infection with colistin-resistant Acinetobacter sp. Different combinations of antibiotics including colistin, meropenem, ampicillin/sulbactam, amikacin and trimethoprim/sulfamethoxazole were used for the treatment of patients with colistin-resistant strains. Although the median duration of microbiological cure (P < 0.001) was longer in the colistin-resistant group, clinical (P = 0.703), laboratory (P = 0.277), radiological (P = 0.551), microbiological response (P = 1.000) and infection related mortality rates (P = 0.603) did not differ between the two groups. Among the patients with infections due to colistin-resistant strains, seven were treated with antibiotic combinations that included sulbactam. Clinical (6/7) and microbiological (5/7) response rates were quite high in these patients.

CONCLUSION

The optimal therapy regimen is unclear for colistin-resistant Acinetobacter sp. infections. Although combinations with sulbactam seems to be more effective in our study patients, data supporting the usefulness of combinations with sulbactam is very limited.

Keywords: Acinetobacter baumannii; Colistin; Ventilator-associated pneumonia

Core tip:Acinetobacter baumannii-calcoaceticus complex (ABC) may cause serious infections. As Acinetobacter species are resistant to many antimicrobials, treatment options for them are extremely limited. Knowing risk factors is important for colistin resistance since colistin seems to be the only remaining therapeutic option for the patients with pneumonia due to extensively drug resistant ABC. We aimed to investigate the risk factors for colistin resistance in ABC strains isolated from the patients with ventilator associated pneumonia (VAP). We also compared clinical response and the outcome between VAP patients due to colistin susceptible and resistant Acinetobacter sp. strains. Furthermore, different treatment combinations were evaluated.