1. AN UNUSUAL PATHOGEN IN HUMANS – Edwardsiella ictaluri
ADEPOJU A.A1,2, ADELAJA A.O1
University College Hospital Ibadan1, College of Medicine University of Ibadan2
INTRODUCTION
Dysentery is a diarrhoeal episode in which the loose or watery stool contains visible blood. It is often caused by infectious agents ranging from bacteria to protozoa.
Edwardsiella ictaluri belongs to the Enterobactericeae family, a gram negative short pleomorphic bacilli which affects fish species only and causes enteric septicaemia of catfish and other species of fish, therefore it is not zoonotic.
DISCUSSION
Edwardsiella ictaluri is primarily a disease of catfish species and causes enteric septicaemia in catfish. Edwardsiella ictaluri has not been isolated in humans. However other species like Edwardsiella tarda also belonging to a genus of gram negative facultatively anaerobic bacteria of the family Enterobacteriaceae is an occassional opportunistic pathogen causing diarrhoea in humans, dogs, pigs and calves.
In the case of this 5 year old boy who presented with dysentery, blood culture using BACTEC grew Edwardsiella ictaluri.
Edwardsiella ictaluri may be a pathogen which can infect humans just like another closely related species – Edwardsiella tarda. More efforts should be made in isolating this organism which may cause morbidity in humans and is of high economic importance in catfish.
CASE REVIEW
A 5 year old boy who presented with fever, vomiting, passage of bloody stool of 6 days and abdominal pain of a day duration.
The family eats catfish occassionally and last consumption of catfish was about 3 weeks before the illness. No similar symptoms in other members of the family.
On examination he was acutely ill, febrile( T – 38.1 C, not pale with generalised abdominal tenderness and guarding but no rebound tenderness. He had hepatomegaly of 4cm and normoactive bowel sounds. Other systems were normal.
Initial diagnosis was acute dysentery R/O typhoid fever.
However blood culture grew Edwardsiella ictaluri, sensitive to gentamycin, levofloxacin, ceftriaxone, cefuroxime, augmentin.
He had 1 week of IV ceftriaxone 100mg/kg/day, symptoms resolved on the 5th day of treatment. Repeat blood culture was sterile after 5 days of incubation.
REFERENCES
Edwardsiellosis caused by Edwardsiella
ictaluri in Laboratory Population of Zebrafish
Danio rerio. John P. Hawke, Michael Kent, (…),
and Tracy Peterson
Use of monoclonal antibodies in the indirect
fluorescent antibody technique (IFA) for the
diagnosis of Edwardsiella ictaluri. Journal of
Fish Diseases. 1986; 9:
Edwardsiella ictaluri sp. Nov: the causative
agent of Enteric septicaemia of Catfish. John P.
Hawke, Almi C. McWhorter, Arnold G.
Steigerwalt, Don J. B. Brenner.
Infections associated with the Genus Edwardsiella:
the Role of Edwardsiella tarda in human disease
J. Michael Sharon L. Abbott
CONCLUSION/RECOMMENDATION
Although Edwardsiella ictaluri has never being isolated in humans, could this be the first case?
Is it an emerging disease?
Is it a case of missed diagnosis?
More efforts at proper investigation and efforts to isolate organisms involved must be made and not just presumotive treatment of cases.
Community research to screen people who regularly consume catfish or close contact with catfish.
Better diagnostic means of identification