Pantoea agglomerans liver abscess in a resident of Brazilian Amazonia

Case Report

Andre Luiz Santos Rodrigues, Isamu Komatsu Lima, Adib Koury Junior, Rafael Maia De Sousa, Lucas Crociati Meguins
Department of General Surgery and Intensive Care Unit
Hospital de Pronto Socorro
Municipal Dr. Humberto Maradei Pereira
Belém, Pará, Brazil.

Corresponding Author: André Luiz Santos Rodrigues
Email: santosrodrigues@superig.com.br

Abstract

Pyogenic liver abscess(PLA) is a potentially life-threatening disease that accounts for about 17.1 cases / 100,000 hospital admissions in Europe.[1] Recent studies indicate a mortality rate varying from 0% to 12.3%.[1,2,3,4] The most commonly isolated pathogens are Klebsiella pneumoniae, Escherichia coli and Peptostreptococcus spp.[1,2,3,4,5,6,7] However, Pantoea agglomerans has rarely been isolated from blood or hepatic purulent material from patients with PLA.[7, 8]

This report describes the case of a Brazilian male patient who presented with liver abscess due to Pantoea agglomerans thirty days after appendectomy.

Case Report

A 59-year-old man, born in and resident of Brazilian Amazonia, was admitted with a 1 week history of fever, chills, confusion, anorexia and upper abdominal pain associated with episodes of diarrhoea and vomiting. His past medical history was remarkable for an uncomplicated appendectomy performed 40 days before the onset of current symptoms. On physical examination, the patient was pale, febrile (38.5 oC), markedly dehydrated, and had tachycardia with an arterial blood pressure of 90/60 mmHg. Clinical assessment of the abdomen demonstrated abdominal tenderness, pain in the right hypochondrium and hepatomegaly. Laboratory blood exams revealed hypochromic anaemia (hemoglobin: 8.6 g/ dL; hematocrit: 24.3%) and leukocytosis with neutrophilia (white blood cell count: 174,000/mm3; 90% neutrophils). Upper abdominal ultrasonography showed two heterogeneous hypoechoic images in the right lobe of the liver measuring 6.42 cm x 5.34 cm and 2.54 cm x 2.13 cm in diameter, respectively, suggesting liver abscess (Figure 1). The patient was initially maintained with clinical support and intravenous antibiotics (Ceftriaxone 2 g/day in a single daily dose and metronidazole 1.5 g/day in three divided doses). However, as no clinical improvement was noted in the following five days with further deterioration in mental status and blood pressure, he underwent ultrasound-guided percutaneous drainage of the liver abscesses. Culture of the purulent material obtained at the time of surgery yielded Pantoea agglomerans (Enterobacter spp.) as the causative agent. His clinical condition and laboratory parameters improved with ongoing antimicrobial (vancomycin 2 g/day in two divided doses and ceftazidime 6 g/day in three divided doses) and fluid therapy. The patient had an uneventful recovery and was discharged 4 weeks after admission in fair clinical condition with normal laboratory parameters and resolving abscess seen on ultrasound. He received a 6-week course of antibiotics and sonographic resolution was seen at three months.

Discussion

Pyogenic liver abscess is a potentially life-threatening hepatic disease that has undergone significant permutation in epidemiology, management and mortality over the past few decades. It occurs secondary to biliary or intestinal infection, hematogeneous spread, extension of contiguous infection, or trauma.[1,3,6,9] Biliary infection is the leading cause of PLA representing 28%-43% of all cases.[3,6] In the present report, the patient detailed recent history of acute appendicitis suggesting possible portal venous infection of the liver.

The most commonly isolated pathogens are Klebsiella pneumoniae, Escherichia coli and Peptostreptococcus spp.[1,2,3,4,5,6,7] However, Pantoea agglomerans, a gram-negative aerobic bacillus in the family Enterobacteriaceae, has been rarely described as the causative agent of PLA.[7,8] All species of the genus Pantoea can be isolated from feculent material of humans and animals, and from plants and soil,[8,10] but P. agglomerans infection is rare in humans and is usually associated with plant thorn arthritis or synovitis.[10,11,12,13] In the case under consideration, P. agglomerans was the only pathogen isolated from culture of the purulent material obtained at the time of surgery.

PLA usually affects the right lobe resulting in multiple lesions.[4,6] Fever, chills and abdominal pain are the most common symptoms with variable duration.[1,2,3,4,5,6,7] Therapeutic management of patients with PLA includes medical treatment with broad-spectrum intravenous antibiotics, percutaneous drainage and/or open surgical drainage. Treatment with ultrasound-guided percutaneous drainage and systemic antibiotics has proved to be an appropriate approach to improving prognosis of patients non-responsive to other treatment modalities or with an underlying disease.[1,2,3,4,5,6] In our case, the patient presented with two lesions in the right hepatic lobe that required drainage due to deterioration of the clinical condition despite continuous intravenous antibiotics. Ultrasound-guided percutaneous drainage was performed safely and the patient was discharged with uneventful recovery.

Conclusion

In conclusion, this case reinforces the importance of P. agglomerans as a possible agent of PLA in patients unresponsive to conventional treatment and highlights the necessity of early suspicion to avoid diagnostic delay and improve outcome.

References

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