Indian Journal of Vascular and Endovascular Surgery

CASE REPORT
Year
: 2021  |  Volume : 8  |  Issue : 4  |  Page : 375--377

Mycotic aortic aneurysm caused by Acinetobacter baumannii complex: A rare case


Naveen Rajendra, Jithin Jagan Sebastian, Athirath Reddy, Arun Kumar, MK Ayappan, Kapil Mathur, Radhakrishnan Raju 
 Department of Vascular Surgery, Sri Ramachandra Medical College, Chennai, Tamil Nadu, India

Correspondence Address:
Naveen Rajendra
Department of Vascular Surgery, Sri Ramachandra Medical College, Chennai, Tamil Nadu
India

Abstract

Mycotic aneurysms are uncommon, difficult to treat, and fatal. These aneurysms caused by Acinetobacter baumannii complex are not documented. We present the case of a 20-year-old female who presented with pain abdomen and vomiting with on and off episodes of fever. This woman had a history of postpartum cardiomyopathy for 12 months and chronic kidney disease for 2 months, on medical treatment. She was diagnosed with an infrarenal aortic aneurysm with iliac extension caused by A. baumannii complex and left hydronephrosis. She was successfully treated with surgery followed by long-term antibiotics. There is no documented evidence of this organism to cause mycotic aneurysm. We also discuss about the course, investigations, and management of this case.



How to cite this article:
Rajendra N, Sebastian JJ, Reddy A, Kumar A, Ayappan M K, Mathur K, Raju R. Mycotic aortic aneurysm caused by Acinetobacter baumannii complex: A rare case.Indian J Vasc Endovasc Surg 2021;8:375-377


How to cite this URL:
Rajendra N, Sebastian JJ, Reddy A, Kumar A, Ayappan M K, Mathur K, Raju R. Mycotic aortic aneurysm caused by Acinetobacter baumannii complex: A rare case. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2022 May 28 ];8:375-377
Available from: https://www.indjvascsurg.org/text.asp?2021/8/4/375/332056


Full Text



 Introduction



Development of a mycotic aneurysm is uncommon but a fulminant process. It is potentially life threatening as it can lead to aortic aneurysm rupture, despite aggressive therapy. Staphylococcus aureus and Salmonella species are pathogens commonly associated with mycotic aneurysm development. We present a case of abdominal aortic mycotic aneurysm in a 20-year-old woman who presented with abdominal pain, vomiting and fever, caused by ACINETOBACTER BAUMANNII COMPLEX.

 Case Report



A 20-year-old female presented to the emergency department with a history of pain abdomen for 2 days and vomiting for 1 day. She gave a history of on and off fever associated with chills for 2 months. She was a known case of hypothyroidism, hypertension, and cardiomyopathy secondary to pregnancy and was on medical treatment. She was also diagnosed with chronic kidney disease for 2 months and was on medical treatment.

On admission, her vitals signs included pulse rate of 92/min, blood pressure of 144/88 mm Hg, respiratory rate of 19/min, and temperature of 100 F. On per abdomen examination, she had tenderness in the left lumbar region and left iliac fossa without any signs of guarding and rigidity.

Laboratory investigations showed a total leukocyte count of 6900/mm3, hemoglobin level of 10.4 g/dl, erythrocyte sedimentation rate (ESR) of 84 mm/h, C-reactive protein (CRP) of 4.2 mg/dl, blood urea of 23 mg/dl, and serum creatinine of 2.6 mg/dl. Contrast-enhanced computed tomography [Figure 1] of the abdomen and pelvis showed aneurysmal dilatation involving the infrarenal aorta, bilateral common and internal iliac artery with chronic thrombosis, multiple areas of parenchymal scarring in both kidneys, mild left hydroureteronephrosis with mild mural thickening, and narrowing of left ureter secondary to chronic periaortitis. Broad-spectrum antibiotics were started at diagnosis after blood cultures had been drawn.{Figure 1}

Given the diagnosis of infected/inflammatory “infrarenal aortic aneurysm with bilateral iliac artery aneurysm and chronic kidney disease,” she was taken up for surgery. Under general anesthesia, bilateral Double J stenting was done, followed by transabdominal approach to the aneurysm. The inflamed aneurysmal aortic wall was debrided and Rifampicin dipped bifurcated Dacron graft was used for aorta to left common iliac and right external iliac bypass followed by right graft to right internal iliac artery bypass [Figure 2]. The wall, plaques and debris were sent for culture and sensitivity.{Figure 2}

Postoperatively, the patient was closely monitored in the intensive care unit for 24 h and later transferred to the ward. The operative tissue culture grew Acinetobacter baumannii complex sensitive to several antibiotics including cefoperazone, ceftazidime, cefotaxime, ciprofloxacin, cefepime, gentamycin, levofloxacin, amikacin, and tetracycline. Blood cultures were negative. She recovered well and was ambulated by day 3 and was discharged on day 8 on ASA and long course of intravenous antibiotic as per the culture for 4 weeks followed by oral ciprofloxacin for 12 weeks, as recommended by the infectious diseases team.

At 1-month follow-up, she was clinically asymptomatic, her renal function was normal, her ESR was 24 mm/h, and CRP was 1.4 mg/dl, which were suggestive of reduction in the inflammatory response. She was advised for the double J stent removal after a month.

 Discussion



Mycotic aortic aneurysm is an uncommon disease that makes up 0.65% to 1.3% of all aortic aneurysms.[1] Microorganisms invade the aortic wall to cause mycotic aortic aneurysms. The mode of invasion may be via septic emboli, bacterial inoculation secondary to trauma, direct extension from adjacent infected fields like lymph nodes, or seeding of the vasa vasorum or of the intimal surface of a preexisting atherosclerotic plaque or aneurysm.[2],[3],[4],[5],[6],[7] Other predisposing factors include intravascular drug abuse, poor immunity, and iatrogenic causes such as catheterizations of the vessels for diagnostic or therapeutic purposes.[6]

Pathogens have been cultured from 46% to 74% of blood samples and 76% of tissue biopsy samples.[8],[9] The most frequent pathogens are S. aureus and Salmonella species,[10],[11],[12] but other organisms (e.g. Bacteroides species) have been occasionally reported as causative pathogens.[12],[13] The incidence of aneurysm rupture and mortality is higher with Gram-negative infections than with Gram-positive infections (84% vs. 10% for rupture and 84% vs. 50% for morality, respectively).[14]

In our patient, the source of the mycotic aneurysm remains unclear. Blood cultures were negative, with only the surgical tissue culture growing A. baumannii complex.

A. baumannii is a Gram-negative bacillus that is aerobic, pleomorphic, and nonmotile. An opportunistic pathogen, A. baumannii, has a high incidence among immunocompromised individuals, particularly those who have experienced a prolonged (>90 days) hospital stay.[15] It colonizes in the skin, respiratory, and oropharynx secretions of the infected individuals.[16] In recent years, it has been designated as a “red alert” human pathogen, generating alarm among the medical fraternity, arising largely from its extensive antibiotic resistance spectrum.[17]

The treatment of mycotic aortic aneurysm combines surgical intervention with intravenous antibiotics. Broad-spectrum antibiotics should be started as soon as there is clinical suspicion of a mycotic aortic aneurysm and can be tailored once cultures return.[2],[18] The gold standard for surgical treatment of infrarenal mycotic aortic aneurysms involves resection of the infected aorta along with extensive debridement of the surrounding periaortic tissue. Revascularization is performed by in situ reconstruction of the aorta or by aortic ligation and extra-anatomic bypass.[1],[19] There is no standardization regarding the conduit to choice. Superficial femoral veins, popliteal veins, cryopreserved arterial homografts, silver-coated Dacron grafts, or antibiotic-bonded grafts have all been tried.[20],[21]

Data regarding antibiotic-soaked grafts such as rifampin-soaked grafts remain mixed. In a canine model, rifampin-bonded gelatin-sealed polyester grafts were found to have significantly decreased rates of reinfection than silver/collagen-coated polyester grafts.[22]

To our knowledge, this is the first case of mycotic aneurysm caused by Acinetobacter baumannii complex. In the future, we hope that definitive treatment guidelines will be established for patients with mycotic aneurysm.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the legal guardian has given his consent for images and other clinical information to be reported in the journal. The guardian understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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