Gnotobiotic piglet infection model for evaluating the safe use of antibiotics against Escherichia coli O157:H7 infection.
BACKGROUND
Shiga toxin (Stx)-producing Escherichia coli (STEC), especially O157:H7, cause bloody diarrhea, and in 3%-15% of individuals the infection leads to hemolytic uremic syndrome (HUS) or other complications. Use of antibiotics to treat STEC infections is controversial. Here, we describe the use of piglets to evaluate the efficacy and mechanism of action of antibiotics in these infections.


METHODS
The effects of 2 antibiotics on STEC toxin production and their mechanisms of action were first determined by enzyme-linked immunosorbent assay and subsequently evaluated clinically in the gnotobiotic piglet infection model.


RESULTS
In vitro treatment of clinical and isogenic strains with ciprofloxacin increased the production of Stx2 via phage induction but not the production of Stx1. Azithromycin caused no significant increase in toxin production. After treatment with ciprofloxacin, infected piglets had diarrhea and the severe fatal neurological symptoms associated with Stx2 intoxication. Characteristic petechial hemorrhages in the cerebellum were more severe in ciprofloxacin-treated animals than in control animals. In contrast, azithromycin-treated piglets survived the infection and had little or no brain hemorrhaging.


CONCLUSIONS
The increased in vitro toxin production caused by ciprofloxacin was strongly correlated with death and an increased rate of cerebellar hemorrhage, in contrast to the effect of azithromycin. The piglet is a suitable model for determining the effectiveness and safety of antibiotics available to treat patients.
Zhang
Quanshun
Q
Division of Infectious Diseases, Department of Biomedical Sciences, Tufts University Cummings School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA.
Donohue-Rolfe
Arthur
A
Krautz-Peterson
Greice
G
Sevo
Milica
M
Parry
Nicola
N
Abeijon
Claudia
C
Tzipori
Saul
S
D000704:Analysis of Variance; D000818:Animals; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D017963:Azithromycin / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D002531:Cerebellum / Q000473:pathology; D016009:Chi-Square Distribution; D002939:Ciprofloxacin / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D005856:Germ-Free Life; D009154:Mutation; D011938:Rec A Recombinases / Q000235:genetics; D022622:Shiga Toxin 1 / Q000378:metabolism; D022641:Shiga Toxin 2 / Q000032:analysis / Q000378:metabolism; D016019:Survival Analysis; D013552:Swine
D000900:Anti-Bacterial Agents; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; D002939:Ciprofloxacin; D017963:Azithromycin; D011938:Rec A Recombinases