Online Letters to the Editors

Environmental Sources Apart From Air Need to Be Investigated First To the Editor:

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n a recent issue of Critical Care Medicine, we read with great interest the article by Munoz-Price et al (1) who demonstrated a high proportion of air samples positive for Acinetobacter baumannii during an investigation on the outbreak of contamination by A. baumannii in a trauma ICU. Furthermore, the authors also found that A. baumannii–contaminated air samples were significantly associated with patients with respiratory specimen positive for A. baumannii (1). However, we are seriously concerned about many confounding factors that were not taken into this analysis. In the study by Munoz-Price et al, it was reported that 11 of 21 patients (52.4%) with respiratory specimen positive for A. baumannii had contaminated air samples, which means that 10 of 21 patients (47.6%) who did not have contaminated air samples, however, had A. baumannii. Furthermore, the percentage of air contamination with A. baumannii was determined only in 7 of 14 patients (50%) with respiratory specimen positive for A. baumannii. Both of the above findings indicate that contaminated air cannot be considered the sole etiology of the outbreak. Therefore, this implies that the outbreak of contamination should have some other etiology. The most important question is that the role of other environmental sources in the outbreak of contamination, such as bedrails, monitors, bedside desks, and bedside sinks, was not clarified in this study. However, these environmental sources were the most common source of outbreak. Possible environmental sources apart from air should be evaluated in the investigation of outbreak of contamination. In summary, the clinical significance of A. baumannii–contaminated air remains unclear. Furthermore, extensive surveillance of environmental sources other than air samples should be performed simultaneously before making a conclusion about the clinical impact of aerosolization of A. baumannii. The authors have disclosed that they do not have any potential conflicts of interest. Chien-Ming Chao, MD, Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying, Tainan, Taiwan; Hsin-Lan Lin, RN, Department of Nursing, Chi-Mei Medical Center, Liouying, Tainan, Taiwan; Chih-Cheng Lai, MD, Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying, Tainan, Taiwan

REFERENCES

1. Munoz-Price LS, Fajardo-Aquino Y, Arheart KL, et al: Aerosolization of Acinetobacter baumannii in a Trauma ICU. Crit Care Med 2013; 41:1915–1918 DOI: 10.1097/CCM.0b013e3182a5257a Copyright © 2013 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins

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www.ccmjournal.org

The authors reply:

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e thank Chao et al (1) for their comments about our work (2). We fully agree with their primary statement that investigation of air contamination with Acinetobacter baumannii should not be performed until the degree of environmental contamination (e.g., bedrails and bedside tables) within the inpatient areas is fully addressed. At our hospital, we have had an endemic situation with carbapenemresistant A. baumannii for almost two decades (3). Even though this was a polyclonal process, the predominant clone (ST79) remained in circulation for 6 years (3). A bundle of interventions was implemented throughout the years in order to contain new acquisitions with A. baumannii (L.S. Munoz-Price, unpublished data, 2013). The bundle consisted of interventions that targeted different pathways of transmission, including contaminated healthcare worker hands by using hand hygiene interventions that included hand cultures (4), contaminated environment, and shared objects (Fig. 1). This is similar to other bundle of interventions implemented for the containment of carbapenem-resistant Enterobacteriaceae (5). In regard to the hospital environment, we performed serial cultures of surfaces across inpatients’ rooms, especially among our ICUs (6). Given the degree of contamination we found, an improvement process of surface disinfection was done using ultraviolet markers (7–9). Currently, we are evaluating the impact of inadvertent exposure to contaminated surfaces with A. baumannii on the later acquisition of this pathogen (L.S. Munoz-Price, unpublished data, 2013). In summary, the investigation of air as a vehicle for the transmission of A. baumannii is only part of our multipronged approach for the containment of this organism. Dr. Doi received grant support from Merck. The remaining authors have disclosed that they do not have any potential conflicts of interest. L. Silvia Munoz-Price, MD,, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, and Department of Anesthesiology, University of Miami Miller School of Medicine, Miami, FL; Nicholas Namias, MD, Department of Surgery, University of Miami Miller School of Medicine, Miami, FL; Yohei Doi, MD, PhD, Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA

REFERENCES

1. Chao C-M, Lin H-L, Lai C-C: Environmental Sources Apart From Air Need to Be Investigated First. Crit Care Med 2013; 41:e480 2. Munoz-Price LS, Fajardo-Aquino Y, Arheart KL, et al: Aerosolization of Acinetobacter baumannii in a trauma ICU. Crit Care Med 2013; 41:1915–1918 3. Munoz-Price LS, Arheart KL, Nordmann P, et al: Eighteen years of experience with Acinetobacter baumannii in a tertiary care hospital. Crit Care Med 2013 Aug 26. [Epub ahead of print] December 2013 • Volume 41 • Number 12

Environmental sources apart from air need to be investigated first.

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