Annals of
Burns and Fire Disasters - vol. XIII - n° 1 - March 2000
CLINICAL INVESTIGATION OF CHANGES IN INTESTINAL MICROFLORA IN BURN PATIENTS AFTER
EARLY ESCHARECTOMY EN MASSE
Jun Chen, Yaping Zhang, Guangxia
Xiao
Institute of Burn Research, Southwestern
Hospital, Chongqing, People's Republic of China
SUMMARY. In order to explore changes in intestinal
microflora and their significance in burn patients undergoing early escharectomy en masse
(EEEM), six kinds of intestinal microflora bacteria in faeces were investigated in 29 EEEM
patients by microbiological methods and compared with those observed in 20 healthy
controls. The results showed that there was a clear decrease in the total number of
intestinal bacterial. The number of aerobes such as E. coli and Candida in EEEM
patients increased more markedly than that of the control. The number of anaerobes such as
Bacteroides, Bifidobacteria, and Fusobacteria in EEEM patients decreased
more markedly than that in nomial controls, indicating that the ecology of the intestinal
microflora was disrupted. Out of 29 patients eight suffered diarrhoea due to intestinal
infection. We therefore concluded that the disruption of the ecology of the intestinal
microflc,ra existed in the early stage after EEEM. It is characterized by anaerobic
bacteria disruption, which can be a major cause of intestinal infection.
Introduction
Thanks to developments in
the knowledge of the pathophysiological changes occurring in severe bums and to the design
of modern equipment for the monitoring of critical burn patients, we can now perform early
escharectomy en masse (EEEM) as early as the burn shock period in major burn patients.
This technique will be beneficial to patients and enable them to recover quickly,
optimally, effectively, and economically.
However, the routine application of large dose of antibiotics to patients subjected to
surgery patients has led to post-operative intestinal infection symptoms, e.g. diarrhoea,
of varying degrees of gravity that may even be fatal in some patients.
We therefore compared the ecology of intestinal microtlora in 29 major burn patients who
underwent EEEM with that of 20 healthy controls. The results were analysed in order to
assess the changes in intestinal microflora ecology that may provide sound indications for
the future effective management of post-burn intestinal microtlora disruption.
Subjects and methods
Clinical data
Operation group.
Twenty-nine severely burned patients (24 male, 5 female) were enrolled in the study and
admitted to our burn ward between November 1994 and March 1997 (average age, 31.6 ± 8.42
yr; range, 18-49 yr; average burned TBSA, 72.1 ± 11.9%; range, 55-97%). All the patients
were treated with our routine institutional methods. All the patients underwent EEEM on
post- operative days 4-6. The operation area covered more than 30%. The patients received
routine post-operative application of powerful broad-spectrum antibiotics according to our
institutional routine. Fresh stool specimens were randomly collected on post-operative
days 1-5.
Control group.
Twenty normal persons (17 male, 3 female) were taken as the control group (average age,
31.9 ± 8.5 yr; range 20-52 yr). None of the contrcls had recently been treated with
antibiotics, hormones, or any other immunosuppressive, radiotherapeutic, or
chemotherapeutic, agents. The sample taking procedure was the same as that followed with
the patients.
Analysis of faecal microflora
All the specimens were
taken immediately to the laboratory and processed within I h. Half a gram was placed in an
anaerobic chamber, diluted tenfold in reduced 0.05% yeast extract solution, and emulsified
in a vortex mixer. Serial tenfold dilutions were performed in reduced 0.05% yeast extract
solution. Samples (0.1 ml) of selected dilution were plated on selective and non-selective
aerobic, anaerobic, and Candida media for enumeration of the members of the
intestinal microflora. The plates were incubated at 37 'C for 24 h for aerobic cultures or
for 48 h in an anaerobic chamber for anaerobic cultures. Plates showing 30 to 300 colonies
were used for bacterial counts. The incubated bacteria or Candida were then counted
and identified.
Results
As illustrated in Table I, the faecal microflora was disrupted in the
post-operative period. The population level of total aerobes, such as E. coli, and Candida
increased twenty to fifty times, while levels of anaerobes, such as Bifidobacteria and
Bacteroides, decreased more than a hundred times. The ratio of aerobes and anaerobe
was disrupted, indicating alteration of the ecology of the intestinal microflora. Of the
29 patients eight (27.6%) suffered from intestinal infection (e.g. diarrhoea).
(Log10cfu/g,
X ± 2SD) |
|
Control |
Operation |
Staphylococcus |
5.23 ± 0,54 |
4.06 ± 0.23** |
E. coli |
5.71 + 0.64 |
6.31 ± 0.5 1 * |
Candida |
3.11 ± 0.37 |
5.88 ± 0.45** |
Bacteroides |
8.14 ± 1.25 |
6.14 ± 0.91 * * |
Fusobacteria |
8.85 ± 1.46 |
6.40 ± 0.87** |
Bifidobacteria |
9.76 ± 1.1 |
6.98 ± 0.76** |
Vs control
* p < 0.05 ** p < 0.01 |
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Table 1 - Dynamic
changes of faecal microflora in the two groups |
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Discussion
The normal bacterial
microflora in the human intestinal lumen is an important microbiological species.
Intestinal lumen aerobes and anaerobes in normal humans maintain a relatively stable
ratio, the micro-ecological balance being maintained by the interaction between the host
and normal physiological bacterial species. 1,2 Disruption of the normal intestinal
microtlora is caused by certain medical interventions, such as surgical operations and the
administration of antibiotics, especially in patients undergoing major escharectomy.'
These factors make the patients prone to intestinal microflora disruption, which is
characterized by an alteration in the number and ratio of various bacteria. Clinical
intestinal disruption exhibits a series of intestinal symptoms such as shapeless stools or
diarrhoea. The principal causes of disturbances in the intestinal microflora are, first of
all, pathophysiological intestinal changes that alter the biological and micro-ecological
circumferences for the colonization of normal intestinal bacterial microflora, with the
result that recessive microflora are dominated. Secondly, the administration of a large
amount of broad-spectrum antibiotics may kill large quantities of normal intestinal
microflora and decrease colonization resistance, which leads to intestinal bacterial
disruption characterized by the overgrowth of some antibioticresistant bacteria and Candida.
A number of studies have suggested that the anaerobic component of the intestinal
microflora is essential for the maintenance of colonization resistance.` The physiological
basis for colonization resistance has been attributed to competition for nutrients,
competition for attachment sites, production of bacteriocins, and production of volatile
fatty acids." The decrease in the number of anaerobes must lead to a decrease in host
colonization resistance, which provokes an outbreak of diseases owing to colonization in
the intestine of exogenous or potentially pathogenic microorganisms.
In our investigation we found that most patients who underwent EEEM exhibited obvious
clinical symptoms in the post-operative period. Some patients even Fresented severe
enteral infection, which was in some cases ultimately fatal. We therefore concluded that
the ecological disruption of the intestinal microflora occurred during the early stage
after EEEM, which may be the result of the comprehensive action of the burn and the
application of broad- spectrum antibiotics. This was one of the direct causes of
intestinal infection. The ecological disruption of intestinal microflora was characterized
by the disruption of anaerobic microflora. However, we still need to study how to apply
these discoveries in clinical practice with burn patients undergoing EEEM.
RESUME. Les Auteurs se sont proposés d'étudier les
modifications de la microflore intestinale et leur importance pour les patients brûlés
traités avec l'escarrectorme précoce en masse (sigle anglais EEEM). Ils ont étudié six
types de bactérie de la microflore intestinale dans les feces de 29 patients qui
suivaient le traitement avec l'escarrectomie précoce en masse, moyennant des méthodes
microbiologiques, et ils ont comparé les résultats aux résultats obtenus dans 20
témoins sains. Ils ont trouvé que le numéro des aérobies comme E. Coli et Candida dans
les patients EEEM augmentait en manière plus marquée que celui des témoins. L-c numéro
des anaérobies comme les Bacteroides, les Bifidobacteria et les Fusobacteria dans les
patients EEEM diminuait en manière plus évidente que celui des témoins. Ces résultats
indiquaient que l'écologie de la microflore intestinale était dérangée. Sur les 29
patients huit ont souffert de diarrhée due à l'infection intestinale. Les Auteurs ont
conclu que le dérangement de l'écologie de la microflore intestinale existait dans la
phase précoce après FEEEM. Cette condition est caractérisée par un dérangement des
bactéries anacrobiques qui peut constituer une cause importante de l'infection
intestinale.
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This paper was received on
22 November 1999. Address correspondence to:
Dr Chen Jun
Institute of Burn Research, Southwestern Hospital
Chongqing, 400038, People's Republic of China
E-mail: chenjun@mail.tmmu.com.cn |
AWARD OF THE G.
WHITAKER
INTERNATIONAL BURNS PRIZE FOR 2000, PALERMO, ITALY
At a meeting held on 24
March 2000 at the seat of the G. Whitaker Foundation, Palermo, after examining the
scientific activity in the fields of research, teaching, clinical organization,
prevention, and co-operation presented by various candidates and in consideration of the
high level of the candidates, the Adjudicating Committee unanimously decided to award the
Prize for 2000 to BASIL PRUITT jr, M.D., Commander and former Director, US Army
Institute of Surgical Research, Texas, USA.
The prize is awarded with the following motivation:
"Having graduated from a most prestigious University, Harvard, in 1957, Dr Pruitt was
drafted in the Army almost immediately, during the Vietnam war, and began a career in
trauma and bums care in war and peace which continues until today, over 43 years: for 27
years, he directed and commanded the US Army Burn Centre, now called the Institute of
Surgical Research.
"On retirement he continued his teaching and operating activity as Professor of
Surgery at the University of Texas Health Sciences Center at San Antonio.
"At all times he has operated, clinically treated, directed, guided research, and
administered burn careat the highest level, making his Centre the largest internationally
recognized Centre of burn excellence in the world.
"An analysis of his many publications as primary author (among his 415 papers)
reveals that he has shown deep interest and has brought scientific contributions to all
the aspects of burns disease. It must be emphasized that bums disease concerns all the
parameters of human physiology and pathology; these render Dr Pruitt's work all the more
capital. This global view is also evident in the work of his collaborators, colleagues,
and researchers whom he has inspired." |
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