Download Acinetobacter Infection: What Was the True Impact during the

MISCELLANY
Acinetobacter Infection:
What Was the True Impact
during the Vietnam Conflict?
Clinton K. Murray,1 Heather C. Yun,2 Matthew E. Griffith,1
Duane R. Hospenthal,1 and Myron J. Tong3
1
Department of Medicine, Infectious Disease Service, Brooke Army
Medical Center, Fort Sam Houston, and 2Department of Infectious
Disease, Wilford Hall Medical Center, Lackland Air Force Base,
San Antonio, Texas; and 3Pfleger Liver Institute, David Geffen
School of Medicine at University of California–Los Angeles
We read with interest 2 recent articles in Clinical Infectious
Diseases highlighting the recognition of Acinetobacter baumannii as one of the more challenging bacteria facing us today [1,
2]. We agree that this bacterium significantly impacts the US
military, because the bacterium frequently colonizes and/or infects our casualties returning from overseas deployments in
support of the global war on terrorism. Although Acinetobacter
species are often reported to have been among the predominant
pathogens infecting war wounds in the Vietnam conflict, there
are significant questions surrounding this assumption.
One of the earliest descriptions of war wound bacteriology
was by Fleming [3] in his 1919 report. He described the evolution of war wounds through 3 phases: initial infection involved sporulating anaerobes (such as Clostridium species) and
streptococci that transitioned, after ∼7 days, to nonsporulating
bacteria of fecal origin (e.g., Escherichia coli and Klebsiella species) and then to pyogenic organisms (including Staphylococcus
species and Streptococcus pyogenes) during the third phase. The
introduction of aggressive surgical debridement likely led to
the essential disappearance of clostridial gas gangrene between
World War I and the Korean War. Implementation of penicillin
treatment during World War II probably led to the diminution
of S. pyogenes infection. The expanded use and broader spectra
of antimicrobial agents occurred simultaneously with the appearance of increasingly resistant bacteria [4, 5].
Received 24 March 2006; accepted 24 March 2006; electronically published 15 June 2006.
The opinions or assertions contained herein are the private views of the authors and are not
to be construed as official or reflecting the views of the Department of Defense or the US
government.
Reprints or correspondence: Dr. Clinton K. Murray, Infectious Disease (MCHE-MDI), Brooke
Army Medical Center, 3851 Roger Brooke Dr., Fort Sam Houston, TX 78234 (Clinton.Murray@
amedd.army.mil).
Clinical Infectious Diseases 2006; 43:383–4
2006 by the Infectious Diseases Society of America. All rights reserved.
1058-4838/2006/4303-0021$15.00
Identifying the role of Acinetobacter species in war wounds
is challenging, because the bacteria’s name has undergone significant evolution [6, 7]. Possibly the first description of Acinetobacter species infection dates back to the Korean War, when
Achromobacter (one of the prior Acinetobacter names) species
was isolated from blood culture of a casualty [8]. Tong’s [9]
1972 description of 30 Marines with 63 extremity wounds is
the most cited description of the role of Acinetobacter infection
in the Vietnam conflict. Culture samples included wound and
blood obtained at the initial time of presentation and then on
dressing change days 3 and 5 after wounding. Initial cultures
were performed within 2.5 h after injury. The article states,
“The predominant gram-negative bacteria on admission were
members of the Mimeae-Herellea-Bacterium-Alcaligenes group”
(p. 1044). The other common gram-negative bacteria included
Pseudomonas aeruginosa and Enterobacter species (table 1). The
Mimeae-Herellea-Bacterium-Alcaligenes group was commonly
identified in bacteremic patients, second only to Enterobacter
species. There is no further description of the microbiology of
the Mimeae-Herellea-Bacterium-Alcaligenes group to enable us
to clearly identify the bacteria today, although by 1971, Acinetobacter was clearly identified as a genus [6, 7]. Tong was not
able to provide further insight into the correct identification
of these bacteria using today’s taxonomy. If this bacterium was
the predominant gram-negative bacterium identified from war
wounds in Vietnam, it is surprising that this is the only report
describing such a fact. Another article from the Vietnam conflict reported findings from 112 initial wound cultures, 2 of
which yielded Alcaligenes (possible Acinetobacter species). The
other gram-negative pathogens identified included Aerobacter
aerogenes and Pseudomonas species, but no Acinetobacter species
or Mimeae-Herellea-Bacterium-Alcaligenes group were described [4]. An analysis of 1531 initial wound cultures performed in Japan from US soldiers wounded in Vietnam during
1967 and 1968 revealed that the most common gram negative
bacteria were P. aeruginosa, Proteus species, E. coli, Aerobacter
aerogenes, and Klebsiella pneumonia [10]. Mimeae-HerelleaBacterium-Alcaligenes group, Acinetobacter, or other names
commonly used for Acinetobacter were not described. Among
orthopedic war wounds evaluated at Brooke General Hospital
(now Brooke Army Medical Center) during the Vietnam conflict, 100 tissue samples revealed that P. aeruginosa, Proteus
species, Klebsiella-Enterobacter group, and E. coli were the predominant gram-negative bacteria identified [11]. Acinetobacterlike bacteria were not identified in this patient population either. Overall, it is unclear what role Acinetobacter played during
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Table 1. The percentage of bacterial cultures of 63 extremity
wound specimens with positive results.
Percentage of
extremity wounds,
by day
a
Pathogen
Pseudomonas aeruginosa
Enterobacter species
Proteus species
Mimeae-Herellea-Bacterium-Alcaligenes group
Escherichia coli
Day 1 Day 3 Day 5
5
38
3
46
25
25
23
8
22
22
67
41
27
25
19
NOTE. Data are from Tong [9].
a
Shown are the 5 most frequently identified gram-negative bacteria.
the Vietnam conflict, in contrast to the role described by most
articles.
Acinetobacter species are associated with war wounds among
casualties returning from the global war on terrorism, although
the source of the infection/colonization is unclear. Three likely
sources have been proposed. The first is that bacteria colonize
soldiers, who are inoculated at the time of injury; the second
is that bacteria are introduced into the wound from the environment at the time of injury; and the third is that nosocomial
infection is responsible, with inoculation occurring during stabilization in theater and/or subsequent evacuation through
higher echelons of medical care. To date, no source has been
clearly identified; however, active investigations are still underway and tend to support nosocomial transmission. Acinetobacter species remain important pathogens among casualties
384 • CID 2006:43 (1 August) • MISCELLANY
because of their multidrug resistant patterns, and we appreciate
the emphasis placed on them by the Infectious Diseases Society
of American and by other authors.
Acknowledgments
Potential conflicts of interest. All authors: no conflicts.
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