Type A aortic dissection associated with Dietzia maris
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a Department of Cardiovascular Surgery, Hospital Universitario La Princesa, Madrid, Spain
b Department of Microbiology, Hospital Universitario La Princesa, Madrid, Spain
c Department of Histiology, Hospital Universitario La Princesa, Madrid, Spain
Abstract
Aortitis is a rare cause of aortic dissection. We report the unusual presentation of a 77-year-old male patient who underwent emergency surgery for an aortic dissection type A. A purulent pericardial fluid and inflammatory aorta were found after chest opening. Several samples were sent for analysis. The ascending aorta presented a mild dilatation with a large haematoma infiltrating the aortic root. The distal part of the ascending aorta seemed unaffected. The aortic rupture was found one centimetre above the non-coronary cusp. Aortic wall tissues were extremely fragile and with an inflammatory aspect. The patient died in the theatre room. In the histological study one out of three fragments of ascending aorta displayed longitudinal splitting of the outer media, with blood extravasation in the adventitial layer. In this level, the presence of a detritus material that reminded of bacterial colonies was noteworthy, together with abundant fibrinous exudates. In the laboratory a new specimen, Dietzia maris, was found in the pericardial liquid and in the aortic wall. We believe that this is the first reported finding of Dietzia maris in a patient with aortic disease.
Key Words: Aortic dissection; Infection; Histology
1. Introduction
Infectious aortitis is an inflammatory process within the arterial wall induced by microorganisms [1]. Infectious aortitis may develop in a normal aorta although it is more frequent in a diseased aorta or in an aortic prosthesis [2]. Nowadays salmonella species have been the primary causes of infectious aortitis [3] among others.
Dietzia maris belongs to a new genus based on 16S ribosomal DNA (rDNA) sequence-based filogenetic evidence [4] and it has been isolated from soil and carp. To our knowledge, we report the first case associating Dietzia maris and a patient with an acute aortic dissection.
2. Case
A 77-year-old male was admitted to the emergency room with mild chest pain. His medical history was remarkable for a prostatic carcinoma, chronic renal failure and Parkinson's disease. Laboratory evaluation showed a white blood cell count of 12.39x109 (82.4% neutrophils) and the patient had no fever. Electrocardiogram showed sinusal rhythm and incomplete right bundle branch block. Cardiac enzyme levels were determined: creatine phosphokinase-MB (CK-MB): 20 U/l and troponin I (TnI): 0.85 ng/ml. With the diagnosis of acute coronary syndrome without ST elevation the patient was admitted to the intensive care unit. The echocardiogram offered a very bad window and the heart seemed unaffected. Due to ongoing dyspnoea, a computed tomography of the chest was performed showing bilateral atelectasis and aortic dissection type A, involving the ascending (with a maximum diameter of 42 mm), and descending aorta. Emergency surgery was planned.
Standard sternotomy was performed. After opening the pericardium 50–70 cc of purulent fluid was found. The liquid was drained and sent for analysis. The ascending aorta presented a mild dilatation with a large haematoma infiltrating the aortic root. The distal part of the ascending aorta seemed unaffected. The right subclavian artery and right atrium were cannulated directly. The patient was cooled to 20 °C and continuous flow made the cerebral protection. The aortic rupture was found one centimetre above the non-coronary cusp. Aortic wall tissues were extremely fragile and with an inflammatory aspect. The ascending aorta was replaced with a synthetic graft (Hemashield no. 28 tube graft). Due to the haematoma and the fragility of tissues, a tear in the aortic root and left atrium junction was seen after rewarming of the patient. This tear caused an uncontrollable bleeding resulting in patient death.
A lot of leukocytes but no microorganisms were observed in Gram-stain. A few orange-pigmented colonies grew after 4 days of incubation and Gram-positive cocci-rods were observed. Because species-level identification was unsuccessful, the strain was sent to a national reference laboratory. Dietzia maris was the definitive identification based on 16S rDNA fraction sequencing. Table 1 shows the antibiotic susceptibility of the microorganism.
In the histological study one out of three fragments of ascending aorta displayed longitudinal splitting of the outer media, with blood extravasation in the adventitial layer. In this level, the presence of a detritus material that reminded of bacterial colonies was noteworthy, together with abundant fibrinous exudates (Fig. 1).
3. Comment
Infectious aortitis may develop in a normal aorta although it is more frequent in a diseased aorta or in an aortic prosthesis [1]. Nowadays salmonella species have been the primary causes of infectious aortitis, often associated with food related gastroenteritis, biliary infection, or lumbar osteomyelitis [3]. However, more pathogens associated with this infection have been described. As far as we know it has never been described as a possible association between Dietzia maris and aortic disease. It is not possible to know if Dietzia maris caused the aortic dissection or it was just a casual finding, as aortitis is a rare cause of aortic dissection [5]. What cannot be denied is that Dietzia maris was found inside the pericardium causing a severe inflammatory reaction in the aortic wall (Fig. 1). When the fluid was cultivated Dietzia maris was found. These findings suggest aortitis as a diagnosis. Computed tomography with contrast is currently the imaging study of choice and features of infectious aortitis are periaortic soft tissue or fluid accumulation, saccular-appearing aneurysm and gas in the aneurysmal sac [6]. However, the computed tomography of this patient only revealed an aortic dissection.
Coincidence in time or a cause-effect relationship between Dietzia maris and aortic dissection is controversial. The history of presentation is not typical and the patient had no fever. It is not easy to know whether the aortitis caused the aortic dissection or if it was an unrelated process (two different diseases). Although isolation was made from purulent pericardial fluid, and pathological findings are compatible with the presence of bacteria within the aortic wall, ideal recovery of Dietzia maris should be made from the aortic specimen, but aortic tissue was not cultured in this case. We think that all suspicious surgical samples should be sent to the microbiology department. Aortic and bone marrow-samples, pericardial fluids, cardiac valves, and pace-maker wires are incubated for at least 30 days in our hospital.
Only two cases of Dietzia maris human infection have been reported previously [7,8]. The presence of foreign material seems to be related to both isolations (a hip prosthesis and a catheter). Dietzia maris has been isolated from soil and carp. There is no evident relation between our patient and fluvial environment although the patient enjoyed hunting.
Why these pathogen isolations are rarely observed may be explained for several reasons. Dietzia spp. and other slow-growing microorganisms are lost in most cases of standard incubation periods, so false sterile cultures could be reported if long-term incubation is not performed. Although basic identification methods and initial susceptibility testing must be performed by the microbiology department, we think that species-level identification based on molecular biology (16S rDNA fraction sequencing) must be provided by a reference laboratory when the usual tests are non-conclusive.
4. Conclusion
This report describes for the first time the finding of Dietzia maris in a patient with an aortic dissection. Since the advent of antibiotics new specimens of bacteria have been described as possible causes of aortitis. The case reported herein prompted us to add Dietzia maris to the list of microorganisms involved in aortic disease. Species-level identification based on molecular biology is needed when the usual tests are non-conclusive to identify these species.
References
Foote EA, Postier RG, Greenfield RA, Bronze MS. Infectious aortitis. Curr Treat Options Cardiovasc Med 2005; 7:89–97.
Oz MC, Brener BJ, Buda JA, Todd G, Brenner RW, Goldenkranz RJ, McNicholas KW, Lemole GM, Lozner JS. A ten-year experience with bacterial aortitis. J Vasc Surg 1989; 10:439–449.
Fernandez Guerrero ML, Aguado JM, Arribas A, Lumbreras C, de Gorgolas M. The spectrum of cardiovascular infections due to Salmonella enterica: a review of clinical features and factors determining outcome. Medicine (Baltimore) 2004; 83:123–138.
Dietzia, a new genus including Dietzia maris comb. nov., formerly Rhodococcus maris Rainey FA, Klatte S, Kroppenstedt RM, Stackebrandt E.
Meehan JJ, Pastor BH, Torre AV. Dissecting aneurysm of the aorta secondary to tuberculous aortitis. Circulation 1957; 16:615–620.
Macedo TA, Stanson AW, Oderich GS, Johnson CM, Panneton JM, Tie ML. Infected aortic aneurysms: imaging findings. Radiology 2004; 231:250–257.
Bemer-Melchior P, Haloun A, Riegel P, Drugeon HB. Bacteremia due to Dietzia maris in an immunocompromised patient. Clin Infect Dis 1999; 29:1338–1340.
Pidoux O, Argenson J-N, Jacomo V, Drancourt M. Molecular identification of a Dietzia maris hip prosthesis infection isolate. J Clin Microbiol 2001; 39:2634–2636.(Guillermo Reyes, Jose-Lui)
b Department of Microbiology, Hospital Universitario La Princesa, Madrid, Spain
c Department of Histiology, Hospital Universitario La Princesa, Madrid, Spain
Abstract
Aortitis is a rare cause of aortic dissection. We report the unusual presentation of a 77-year-old male patient who underwent emergency surgery for an aortic dissection type A. A purulent pericardial fluid and inflammatory aorta were found after chest opening. Several samples were sent for analysis. The ascending aorta presented a mild dilatation with a large haematoma infiltrating the aortic root. The distal part of the ascending aorta seemed unaffected. The aortic rupture was found one centimetre above the non-coronary cusp. Aortic wall tissues were extremely fragile and with an inflammatory aspect. The patient died in the theatre room. In the histological study one out of three fragments of ascending aorta displayed longitudinal splitting of the outer media, with blood extravasation in the adventitial layer. In this level, the presence of a detritus material that reminded of bacterial colonies was noteworthy, together with abundant fibrinous exudates. In the laboratory a new specimen, Dietzia maris, was found in the pericardial liquid and in the aortic wall. We believe that this is the first reported finding of Dietzia maris in a patient with aortic disease.
Key Words: Aortic dissection; Infection; Histology
1. Introduction
Infectious aortitis is an inflammatory process within the arterial wall induced by microorganisms [1]. Infectious aortitis may develop in a normal aorta although it is more frequent in a diseased aorta or in an aortic prosthesis [2]. Nowadays salmonella species have been the primary causes of infectious aortitis [3] among others.
Dietzia maris belongs to a new genus based on 16S ribosomal DNA (rDNA) sequence-based filogenetic evidence [4] and it has been isolated from soil and carp. To our knowledge, we report the first case associating Dietzia maris and a patient with an acute aortic dissection.
2. Case
A 77-year-old male was admitted to the emergency room with mild chest pain. His medical history was remarkable for a prostatic carcinoma, chronic renal failure and Parkinson's disease. Laboratory evaluation showed a white blood cell count of 12.39x109 (82.4% neutrophils) and the patient had no fever. Electrocardiogram showed sinusal rhythm and incomplete right bundle branch block. Cardiac enzyme levels were determined: creatine phosphokinase-MB (CK-MB): 20 U/l and troponin I (TnI): 0.85 ng/ml. With the diagnosis of acute coronary syndrome without ST elevation the patient was admitted to the intensive care unit. The echocardiogram offered a very bad window and the heart seemed unaffected. Due to ongoing dyspnoea, a computed tomography of the chest was performed showing bilateral atelectasis and aortic dissection type A, involving the ascending (with a maximum diameter of 42 mm), and descending aorta. Emergency surgery was planned.
Standard sternotomy was performed. After opening the pericardium 50–70 cc of purulent fluid was found. The liquid was drained and sent for analysis. The ascending aorta presented a mild dilatation with a large haematoma infiltrating the aortic root. The distal part of the ascending aorta seemed unaffected. The right subclavian artery and right atrium were cannulated directly. The patient was cooled to 20 °C and continuous flow made the cerebral protection. The aortic rupture was found one centimetre above the non-coronary cusp. Aortic wall tissues were extremely fragile and with an inflammatory aspect. The ascending aorta was replaced with a synthetic graft (Hemashield no. 28 tube graft). Due to the haematoma and the fragility of tissues, a tear in the aortic root and left atrium junction was seen after rewarming of the patient. This tear caused an uncontrollable bleeding resulting in patient death.
A lot of leukocytes but no microorganisms were observed in Gram-stain. A few orange-pigmented colonies grew after 4 days of incubation and Gram-positive cocci-rods were observed. Because species-level identification was unsuccessful, the strain was sent to a national reference laboratory. Dietzia maris was the definitive identification based on 16S rDNA fraction sequencing. Table 1 shows the antibiotic susceptibility of the microorganism.
In the histological study one out of three fragments of ascending aorta displayed longitudinal splitting of the outer media, with blood extravasation in the adventitial layer. In this level, the presence of a detritus material that reminded of bacterial colonies was noteworthy, together with abundant fibrinous exudates (Fig. 1).
3. Comment
Infectious aortitis may develop in a normal aorta although it is more frequent in a diseased aorta or in an aortic prosthesis [1]. Nowadays salmonella species have been the primary causes of infectious aortitis, often associated with food related gastroenteritis, biliary infection, or lumbar osteomyelitis [3]. However, more pathogens associated with this infection have been described. As far as we know it has never been described as a possible association between Dietzia maris and aortic disease. It is not possible to know if Dietzia maris caused the aortic dissection or it was just a casual finding, as aortitis is a rare cause of aortic dissection [5]. What cannot be denied is that Dietzia maris was found inside the pericardium causing a severe inflammatory reaction in the aortic wall (Fig. 1). When the fluid was cultivated Dietzia maris was found. These findings suggest aortitis as a diagnosis. Computed tomography with contrast is currently the imaging study of choice and features of infectious aortitis are periaortic soft tissue or fluid accumulation, saccular-appearing aneurysm and gas in the aneurysmal sac [6]. However, the computed tomography of this patient only revealed an aortic dissection.
Coincidence in time or a cause-effect relationship between Dietzia maris and aortic dissection is controversial. The history of presentation is not typical and the patient had no fever. It is not easy to know whether the aortitis caused the aortic dissection or if it was an unrelated process (two different diseases). Although isolation was made from purulent pericardial fluid, and pathological findings are compatible with the presence of bacteria within the aortic wall, ideal recovery of Dietzia maris should be made from the aortic specimen, but aortic tissue was not cultured in this case. We think that all suspicious surgical samples should be sent to the microbiology department. Aortic and bone marrow-samples, pericardial fluids, cardiac valves, and pace-maker wires are incubated for at least 30 days in our hospital.
Only two cases of Dietzia maris human infection have been reported previously [7,8]. The presence of foreign material seems to be related to both isolations (a hip prosthesis and a catheter). Dietzia maris has been isolated from soil and carp. There is no evident relation between our patient and fluvial environment although the patient enjoyed hunting.
Why these pathogen isolations are rarely observed may be explained for several reasons. Dietzia spp. and other slow-growing microorganisms are lost in most cases of standard incubation periods, so false sterile cultures could be reported if long-term incubation is not performed. Although basic identification methods and initial susceptibility testing must be performed by the microbiology department, we think that species-level identification based on molecular biology (16S rDNA fraction sequencing) must be provided by a reference laboratory when the usual tests are non-conclusive.
4. Conclusion
This report describes for the first time the finding of Dietzia maris in a patient with an aortic dissection. Since the advent of antibiotics new specimens of bacteria have been described as possible causes of aortitis. The case reported herein prompted us to add Dietzia maris to the list of microorganisms involved in aortic disease. Species-level identification based on molecular biology is needed when the usual tests are non-conclusive to identify these species.
References
Foote EA, Postier RG, Greenfield RA, Bronze MS. Infectious aortitis. Curr Treat Options Cardiovasc Med 2005; 7:89–97.
Oz MC, Brener BJ, Buda JA, Todd G, Brenner RW, Goldenkranz RJ, McNicholas KW, Lemole GM, Lozner JS. A ten-year experience with bacterial aortitis. J Vasc Surg 1989; 10:439–449.
Fernandez Guerrero ML, Aguado JM, Arribas A, Lumbreras C, de Gorgolas M. The spectrum of cardiovascular infections due to Salmonella enterica: a review of clinical features and factors determining outcome. Medicine (Baltimore) 2004; 83:123–138.
Dietzia, a new genus including Dietzia maris comb. nov., formerly Rhodococcus maris Rainey FA, Klatte S, Kroppenstedt RM, Stackebrandt E.
Meehan JJ, Pastor BH, Torre AV. Dissecting aneurysm of the aorta secondary to tuberculous aortitis. Circulation 1957; 16:615–620.
Macedo TA, Stanson AW, Oderich GS, Johnson CM, Panneton JM, Tie ML. Infected aortic aneurysms: imaging findings. Radiology 2004; 231:250–257.
Bemer-Melchior P, Haloun A, Riegel P, Drugeon HB. Bacteremia due to Dietzia maris in an immunocompromised patient. Clin Infect Dis 1999; 29:1338–1340.
Pidoux O, Argenson J-N, Jacomo V, Drancourt M. Molecular identification of a Dietzia maris hip prosthesis infection isolate. J Clin Microbiol 2001; 39:2634–2636.(Guillermo Reyes, Jose-Lui)