Splenic Abscesses Caused by a Reptile-Associated Salmonella Infection

Splenectomy due to splenic abscesses is an unusual occurrence, especially in Western countries. The role of foods is a well-known phenomenon for Salmonella infections. Here, we want to illustrate the importance of a child’s environment in the development of salmonellosis, in particular the role of home (reptile) pets.

A previously healthy 17-year-old girl presented at the emergency department with a 2-day history of progressive left upper abdominal pain, fever, and cold shivers. The complaints started with feelings of total malaise with diarrhoea without blood or mucus infiltration. At home, she had a temperature of 39°C. Her family had a negative medical history concerning immunosuppressive diseases. No family members demonstrated signs of fever or illness. She never visited the tropics.

Physical examination presented a sick girl, length 1.73 m, weight 88 kg. The rectal temperature was 39.8°C. The blood pressure was 100/50 mm Hg and the heart rate 120/min, regular and equal. Auscultation of heart and lungs revealed no abnormalities. She had severe left upper abdominal pain, without the presence of muscular defence. The abdomen gave sparse peristalsis, with a varying tympanitic sound on percussion. The spleen was enlarged on palpation. There was no pain on palpation in the renal lodges. Skin and extremities appeared without abnormalities.

Laboratory results: white blood cells 7.4×10⁹/l (basophils <0.1×10⁹/l; eosinophils <0.1×10⁹/l; lymphocytes 0.5×10⁹/l; neutrophils 5.8×10⁹/l, and monocytes 0.3×10⁹/l with C-reactive protein 377 mg/l); liver and renal functions were normal, except for a lactate dehydrogenase level of 492 U/l.

A chest X-ray gave us no explanation for the clinical symptoms. Ultrasound investigation of the abdomen identified an enlarged spleen of 23.3 cm. The rest of the spleen showed multiple, partly merging hypodense lesions. The remaining organs demonstrated no abnormalities. A CT scan of the abdomen revealed multiple splenic abscesses (fig. 1, 2).

On admission, the patient was taken to the intensive care unit with the diagnosis of sepsis and multiple splenic abscesses. Empirical intravenous antibiotic treatment was started (amoxicillin with clavulanic acid 3×2.2 g and gentamicin 4 mg/kg/24 h) after obtaining blood samples. We decided to perform a laparotomy. An enlarged spleen was seen, with a fragile capsule on the lateral side which perforated during the procedure. The discharged pus was collected for culture. Splenectomy was performed. Blood samples and samples of the abscesses revealed growth of a Salmonella species; gentamicin was replaced by ciprofloxacin (2×400 mg i.v.). On day 4 after admission, she was transferred to the surgical ward. On day 15 she was discharged. We started vaccination 4 weeks after surgery. Until the start of the vaccination period, the patient received antibiotic prophylaxis. Thirteen months after surgery, she is doing very well.

The Salmonella species was typed at the National Institute for Public Health and Environment (RIVM) as Salmonellaenterica subsp. enterica Telelkebir which is associated with reptiles. On inquiry, it appeared that the patient had multiple different reptiles as pets. We took some faecal samples from these reptiles (a salamander and a bearded dragon), from which S.enterica subsp. enterica Telelkebir was isolated.

Salmonella species are Gram-negative, facultative anaerobe rods within the family of the Enterobacteriaceae. They can be found as commensal bacteria and are pathogenic to mammals (including humans), reptiles, birds, and even insects. Some serovars can infect multiple hosts, others are specific for bovine animals or reptiles and only rarely cause infections in humans.

Exotic pets are often carriers of Salmonella species. Some studies have shown that in approximately 3–5% of the cases of Salmonella infection a pet is the source [1, 2]. Often it concerns turtles, Iguanidae, or snakes, but also other reptiles, birds, and mammals. Especially children, the elderly, and immunocompromised persons are at risk of infections. Unfamiliarity with the risks of contamination of the owners of the pets seems to play an important role. An information campaign carried out in Sweden reduced the incidence of reptile-associated Salmonella infections from 0.79 to 0.46 cases per 100,000 population [3].

During the period 1998–2005, the RIVM typed 14 human isolates of Salmonella as S.enterica subsp. enterica Telelkebir. Two of these samples were isolated from blood cultures, one was cultured from a surgical drain, and the remaining eleven were isolated from faecal samples. Of these patients, 5 were 0–9 years old, 3 were 10–19 years old, 2 were 20–69 years old, and 4 were 70 years old or older. 3 out of the 14 patients were male.

Currently, the genus Salmonella consists oftwo species: S.choleraesuis or Salmonellaenterica and Salmonellabongori. The first species can be subdivided into six subspecies. Among these subspecies, distinction exists in serovars according to the O, Vi, and H antigens. These serovars within S. enterica subsp. enterica bear often the name of the locality where they have occurred first, e.g., the Egyptian village of Tel-el-Kebir.

Besides typhoid fever caused by Salmonellatyphi and Salmonellaparatyphi and gastro-enteritis caused by other Salmonella species, extra-intestinal infections can also occur. Other infections that have been described include endocarditis, mycotic aneurysm, infections of the central nervous system, pneumonia, osteomyelitis, arthritis, soft-tissue infections, cholecystitis, urogenital infections, and, in rare cases, splenic abscesses [4].

A splenic abscess is an exceptional disorder, and the symptoms are little specific [5]. When the diagnosis is considered, the best way to confirm is supplementary imaging (ultrasound, CT, or MRI). At present, splenectomy is the gold standard for treatment [5,6,7]. But ultrasound- or CT-assisted draining is an increasingly accepted method of treatment, especially in the presence of an isolated abscess [7, 8].

To conclude, exotic pets form an often unrecognized source of Salmonella infections which can be serious, even in apparently healthy persons.

The authors would like to thank Mrs. H. Maas of the National Institute for Public Health and Environment (RIVM) for the characterisation of the isolates and for the summary of the S. Telelkebir isolates typed in the period of 1998–2005.