A possible animal model for critical colonisation.
OBJECTIVE
To develop a critical colonisation model in rats that will facilitate investigation of its pathophysiology and the development of new and effective diagnosis and treatment protocols.


METHODS
Three groups of rats were given full-thickness dorsal wounds: a control group received phosphate-buffered saline; an experimental group was inoculated with Pseudomonas aeruginosa; an infection group with streptozotocin-induced diabetes was also inoculated with P. aeruginosa. All groups were assessed on a number of parameters at days 1, 3, 5 and 7 following wounding. Parameters included gross observations, histopathological observations, quantification of redness and swelling, serum C-reactive protein (CRP) measurement and tissue bacterial counts.


RESULTS
Healing was delayed in the experimental group when compared with the control group, with no signs of inflammation. Although the numbers of bacteria were similar in the experimental and infection groups, polymorphonuclear neutrophil (PMN) infiltration was localised to granulation tissue in the experimental group, whereas it extended to muscular tissue in the experimental group. CRP levels remained low in the experimental group.


CONCLUSIONS
These findings suggest that the inoculation of bacteria provides a possible model of critical colonisation in rats. We believe this will contribute to a better understanding of critical colonisation.
Ueda
K
K
Department of Nursing, University of Tokyo Hospital, Tokyo, Japan.
Akase
T
T
Nakagami
G
G
Nagase
T
T
Minematsu
T
T
Huang
L
L
Sagara
H
H
Ohta
Y
Y
Sanada
H
H
D000704:Analysis of Variance; D000818:Animals; D002097:C-Reactive Protein / Q000032:analysis; D015169:Colony Count, Microbial; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D004195:Disease Models, Animal; D006097:Granulation Tissue / Q000473:pathology / Q000502:physiology; D008297:Male; D020556:Neutrophil Infiltration / Q000502:physiology; D009504:Neutrophils / Q000473:pathology / Q000502:physiology; D011552:Pseudomonas Infections / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D014945:Wound Healing / Q000502:physiology; D014946:Wound Infection / Q000209:etiology / Q000473:pathology / Q000503:physiopathology
D002097:C-Reactive Protein