|Year : 2016 | Volume
| Issue : 3 | Page : 395-396
Aeromonas : An unusual cause of lower gastrointestinal bleed
J Mandal1, S Kumaravel2, V Ganesan1
1 Department of Microbiology, JIPMER, Puducherry, India
2 Department of Pediatric Surgery, JIPMER, Puducherry, India
|Date of Submission||05-Jun-2015|
|Date of Acceptance||07-Mar-2016|
|Date of Web Publication||12-Aug-2016|
Department of Microbiology, JIPMER, Puducherry
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mandal J, Kumaravel S, Ganesan V. Aeromonas : An unusual cause of lower gastrointestinal bleed. Indian J Med Microbiol 2016;34:395-6
|How to cite this URL:|
Mandal J, Kumaravel S, Ganesan V. Aeromonas : An unusual cause of lower gastrointestinal bleed. Indian J Med Microbiol [serial online] 2016 [cited 2020 Oct 25];34:395-6. Available from: https://www.ijmm.org/text.asp?2016/34/3/395/188375
The identity of Aeromonas as a true enteropathogen is elusive till date though the members of this genus have been associated with many clinical manifestations beginning with acute gastroenteritis to severe manifestations of septicaemia resulting from fulminant colitis.  Rare associations of Aeromonas with ischaemic colitis have also been documented earlier. , Herein, we describe a small child with a rare manifestation of a lower gastrointestinal bleed due to Aeromonas.
A 6-year-old boy was admitted in the paediatric surgery ward of our hospital, with the complaints of abdominal pain for 2 days and vomiting for 1 day with a history of passing maroon-coloured stools. There was no history of associated fever or any particular food intake. On examination, the child was afebrile, hydrated and no abdominal tenderness could be elicited. A provisional diagnosis of ischaemic colitis or bleeding Meckel's diverticulum was made. The child was treated conservatively with intravenous fluids. During admission, the haemoglobin was 15.4 g%. Ultrasound of the abdomen showed a normal study. After 2 days, the child developed fever and continued to pass maroon-coloured stools more frequently. On investigation, the haemoglobin was 12.2 g%, the red blood cell count was 4.4 million/cumm, the leucocyte count was 4390/cumm and the platelet count was 201,000/cumm of blood. The blood glucose was 71 mg%, serum urea was 23 g%, serum creatinine was 0.5 g% and serum sodium/potassium level was 138/4.7 mEq. A repeat ultrasound examination of the abdomen revealed a few small mesenteric nodes. Freshly passed stool sample was sent for culture which revealed flat translucent non-lactose fermenting colonies on MacConkey agar. The isolate was catalase and oxidase positive and showed darting motility. The string test was negative, indole test was positive, Kligler iron agar showed alkaline slant and acidic but without any gas production, fermented glucose (without gas), sucrose, arabinose and mannitol, Voges-Proskauer test was negative, ortho-nitrophenyl β-D-galactopyranoside was hydrolysed, aesculin and arginine were hydrolysed and lysine and ornithine were not de-carboxylated. Based on these biochemical tests, the organism was identified as Aeromonas caviae. We could not test the isolate with the O/129 reagent as it was not available in the laboratory at the time of this isolation. The isolate was sensitive to co-trimoxazole, ciprofloxacin, tetracycline and ceftriaxone by the Kirby-Bauer's method of disc diffusion testing as per the Clinical Laboratories Standards Institute.  The child was maintained with intravenous fluids, ceftriaxone was started and eventually his condition improved, started passing normal stools. The child was discharged after 8 days of hospitalisation.
Aeromonas is responsible for a number of mild intestinal and severe extra-intestinal diseases and syndromes. Gastroenteritis due to Aeromonas is a relatively mild manifestation of cholera-like disease or an extremely rare dysenteric form ensuing from inflammation of the large intestine.  Definitive diagnosis in most instances is achieved by the isolation of Aeromonas spp. from stool cultures or other gastrointestinal samples.
Ischaemic colitis can be classified as reversible ischaemic colonopathy (IC) or transient IC, chronic IC, ischaemic colonic stricture, colonic gangrene and fulminant.  The reversible variety is the most common. Such cases resolve by themselves with minimal supportive management based on the hydration therapy and rest to the colon and antibiotics. The prognosis of IC is mostly proportional to age of the patient and is worse in the elderly patients. Many organisms have been known to lead to ischaemic colitis, and rare associations of Aeromonas with ischaemic colitis have also been documented earlier. , In the absence of other evidence such as intestinal biopsy or endoscopy findings and in the presence of a self-limiting nature of the illness with the presence of mesenteric lymphadenitis and the stool culture yielding Aeromonas spp., an infective aetiology of the underlying condition was considered most probable. Finally, a post-infectious ischaemic colitis was considered in this case. The ischaemic colitis resolved with rehydration therapy and appropriate antimicrobial therapy, and the child was discharged after an in-hospital stay of 8 days. Hence, infective agents such as Aeromonas species need to be considered in the differential diagnosis in cases of colitis, and stool culture is a very simple, non-invasive test that can be offered in such cases.
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