Nephrol Dial Transplant (1991) 6: 209-214 © 1991 European Dialysis and Transplant Association-European Renal Association
Nephrology Dialysis Transplantation
Case Report Disseminated Infection of the Central Nervous System Caused by Nocardia farcinica K. Miksits1, G. Stoltenburg2, H.-H. Neumayer3, H. Spiegel4, K. P. Schaal5, J. Cervos-Navarro2, A. Distler3, H. Stein4 and H. Hahn1 'Institut fur Medizinische Mikrobiologie und Infektionsimmunologie der FU Berlin; 2Abteilung fur Neuropathologie im Klinikum Steglitz der FU Berlin; 3Medizinische Klinik und Poliklinik im Klinikum Steglitz der FU Berlin, 4Abteilung fur Pathologie im Klinikum Steglitz der FU Berlin; 5Institut fur Medizinische Mikrobiologie und Immunologie der Universitat Bonn, Germany
Key words: CNS infection; Immunocompromised host; neoformans, T. gondii, and Nocardia species, e.g. Nocardiosis; Nocardia farcinica; Renal transplant reci- N. asteroid.es [1]. Here we report on a renal transplant recipient in pient whom multiple brain abscesses were caused by N. farcinica; it is the first case of that infection in this transplantation unit. This organism has been described as a human pathogen in 56 cases of infection since it has Introduction regained its formal standing in taxonomy and nomenclaDuring the last two decades renal transplantation has ture between 1969 and 1978 [2-8]. In addition, it is become the treatment of choice in patients with chronic apparently isolated from compromised hosts with renal failure. Immunosuppressive therapy, albeit increasing frequency: in the last 3 months, we could necessary, results in a greater susceptibility of the isolate this pathogen from three different patients (idenrecipient to infectious diseases [1]. Infections of the tification performed by Professor K. P. Schaal; unpubcentral nervous system (CNS), such as meningitis, lished data). meningoencephalitis, and brain abscesses are a major cause of morbidity and mortality in renal transplant recipients [1]. In the immunocompromised host they are Case Report usually caused by microorganisms different from those found in the general population [1]. Acute meningitis A 55-year-old female renal allograft recipient (donor is commonly caused by L. monocytogenes, whereas CMV-antibody-positive) was admitted to the Klinikum C. neoformans results in a more chronic course. Menin- Steglitz with a 1-week history of nausea, vomiting and goencephalitis is frequently caused by viruses, e.g. headache. The presence of cytotoxic antibodies and a papovaviruses. Brain abscesses in renal transplant successfully treated rejection reaction necessitated recipients are typically caused by Aspergillus species, irnmunsuppression by a triple-drug therapy consisting of but are also frequently due to L. monocytogenes, C. low-dose a-methylprednisolone, cyclosporin A, and azathioprine since transplantation 8 months ago. One Correspondence and offprint requests to: Dr Klaus Miksits, Institut fur month before the actual admission, the patient had Medizinische Mikrobiologie und Infektionsimmunologie der FU already been hospitalised for nausea, vomiting, and Berlin, Hindenburgdamm 27, D(W)-1000 Berlin 45, Geamany.
K. Miksits et al
210 Cyclosporin A Methylprednisolone Azathioprine PyrimethamiDe Acyclovir
Clindamycln Ceftazldime FlucloxaciHtn Metronldazole Ciprofloxacln Amphoterlcln B Flucytoslne body temperature/°C 40 -
200 ^ diagnostic procedures days
p.5 fl7 (19 |21 |23 [25 (27 (29 pi |33 p5 |37 Died
CCT: cranial computed tomography NMRT: nuclear magnetic resonance tomography biopsy: brain biopsy via burr hole CM-CCT: cranial computed tomography with using contrast medium HE* haemodialysis BS: bronchoscopy [7H period at Intensive care unit Fig. 1. Clinical course of CNS-infection caused by Nocardia farcinica.
fever. With regard to repeated urinary tract infections after transplantation, but despite the lack of any significant microbiological findings, an urosepsis was diagnosed. Treatment with cefotaxime improved the patient's physical condition and so medical care was continued on an outpatient basis. A chest X-ray did not reveal any pathological changes; a cranial computed tomography (CCT) was not performed. The clinical examination now revealed tiredness, a fine tremor of the hands, and intermittent myocloni of
the legs. The major findings were signs of meningeal irritation. CCT both without and with contrast medium, and nuclear magnetic resonance tomography (NMRT) showed multiple intracerebral processes thought to be abscesses (Figs 1, 2a). Signs of increased intracranial pressure necessitated the cancellation of a lumbar puncture. A brain biopsy revealed a lymphocytic-plasmacytic-histiocytic infiltrate considered to be indicative of subacute encephalitis. Neither bacteria (a complete microbiological examination was performed, including
CNS Infection Caused by N. farcinica
a thioglycollate broth culture and a blood agar culture incubating for 10 days) nor other microorganisms (e.g. T. gondii, CMV, HIV, or fungi) could be demonstrated in these biopsies. The only evidence indicative of infection was the serological demonstration of IgM antibodies to CMV. Based on clinical and radiological findings, an antimicrobial therapy was initiated, including pyrimethamine, acyclovir, clindamycin, and ceftazidime. Because of the deterioration of the physical condition despite this treatment, the antimicrobial regimen was changed toflucloxacillin,metronidazole, ciprofloxacin, pyrimethamine, amphotericin B, and flucytosine (Fig. 1). Subsequently the patient became increasingly somnolent and showed an increase in body temperature as well as a reduction of renal allograft function (determined by serum creatinine concentration). Therefore she underwent haemodialysis (Fig. 1). An angiodynography showed a missed diastolic flow as a sign of rejection or toxic renal injury. The most spectacular symptom during this period was intensive hyperventilation. Chest X-rays revealed progressive bronchopneumonia but no microbial pathogen could be isolated. Concomitant signs of persistent and progressive elevation of intracranial pressure made it impossible to repeat brain biopsy or to perform other neurosurgical invasive procedures. Increasing loss of consciousness and steady increase in intracranial pressure together with signs of axial herniation led to coma, despite recovery of allograft function and receding of the radiological signs of bronchopneumonia. Thirtyseven days after admission, brain death was diagnosed (Fig. 1). The pathological examination revealed the following findings: The lungs showed a mild bronchopneumonia caused by CMV, which was demonstrated by staining with a monoclonal antibody and a DNA probe. The kidneys were completely atrophic. In the allograft, there were only isolated signs of tubular necrosis, but no findings indicative of a severe rejection reaction could be demonstrated. Brain volume was increased, as shown by tonsillar coning. The cisterns on the brain base were filled with creamy pus. Leptomeninges on the surface of the spinal cord showed scattered foci of white adherent spheroids (Fig. 2f). Gross appearance on horizontal sections showed lesions - multiple abscesses - corresponding to CCT and NMRT findings (Fig. 2a, b). The stereotactic biopsy was accidentally taken from brain tissue between two abscess holes so that only chronic inflammatory change and no specific pattern or bacteria could be found by special staining in this region. The abscesses in the right cerebellar hemisphere were
211
2f
Fig. 2. Radiological and pathological signs of nocardiosis. (a) NMRT scan of structures of posterior fossa: two encapsulated abscesses with surrounding oedema in the right cerebellar hemisphere; (b) autopsy specimen of corresponding level of brain stem and cerebellum: note abscess cavities in the cerebellum and haemorrhagic necroses of inferior olives; (c) Grocott impregnation (x200): abundant masses of nocardia along the border of the intact brain tissue; (d) Grocott impregnation (xSOO): typically black threadlike structures; (e) meningitis and vasculitis in the meninges of lower brain stem (H&E, X200); (f) caudal portion of the spinal cord: multiple granulomas in the leptomeninges.
filled with necrotic material. Grocott impregnation revealed typically threadlike structures darkly stained black at the border of the abscesses and surrounding tissue (Fig. 2c, d). Most remarkable was the involvement of vessels in the inflammatory process which caused microcirculatory disturbances and haemorrhagic necrosis in the olives (Fig. 2e). These black threadlike structures were also detected in the border zone of all other abscesses and in the inner and outer cerebral spine fluid space.
212
Microbiological evaluation revealed these as N. farcinica, susceptible to amikacin only. Identification was achieved using the methods and criteria described by Schaal, and Goodfellow and Lechevalier [9-12]. These included chemotaxonomic tests (demonstration of mesodiaminopimelic acid in whole-cell hydrolysates and mycolic acid analysis), utilisation tests with a variety of carbon and carbon plus nitrogen sources, as well as more traditional hydrolysis tests [9-11]. The strain contained mesodiaminopimelic acid and mycolic acids giving single spots on thin-layer plates identical to that of typical nocardiae. On the basis of these results, the organism could definitely be assigned to the genus Nocardia. In the utilisation tests, the organism grew well on 2,3-butylene glycol, 1,2-propylene glycol, and L-rhamnose, but not adonitol, L-arabiose, benzoate, citrate, sodium gluconate, mesoinositol, D-mannitol, D-sorbitol or D-xylose as sole carbon sources. It did not utilise gelatin and L-serine as sole N+C sources. Esculin hydrolysis and urease activity were positive; testosterone, but not casein, tyrosine, xanthine, hypoxanthine, or adenine were degraded. This pattern of physiological reactions clearly showed the organism to belong to the species N. farcinica and distinguished it from N. asteroides as currently defined. Furthermore, the strain was resistant to all the aminoglycosides except amikacin, to penicillins and cephalosporins as well as to vancomycin, which is in accordance with the susceptibility data published for N. farcinica [13].
Discussion Nocardia species, a major cause of brain abscesses in immunocompromised hosts, are branched filamentous bacteria that form a fugacious mycelium that tends to break up into rod-shaped or coccoid elements. They are Gram-positive, but may stain irregularly. Some strains are weakly and partially acid-fast [12,14,15]. Blood agar is a satisfactory medium for primary isolation but colony formation takes 4-10 days, while subcultures grow after 48 h of incubation. Therefore, the microbiological laboratory must be informed about suspected nocardiosis to extend the routine incubation period. Colonies may show an off-white, grey, yellow, orange, pink, peach, red, tan, brown, or purple pigmentation and some cultures emanate a musty odour [12,14,15]. N. farcinica colonies are usually orange with sparse to moderate white aerial hyphae. N. farcinica was first described by Nocard in 1888 as the causative agent of bovine farcy in the West Indies [16]. Trevisian gave the designation Nocardia to this genus and nanied the species N. farcinica [17]. Nocard's original isolate is represented by two supposed identical, but actually very different strains in two culture
K. Miksits et al
collections, ATCC 3318 and NCTC 4524 [12]. One of them [ATCC 3318) is a typical nocardia, whereas the second one (NCTC 4524) contains mycolic acids and mycosides characteristic of mycobacteria. Strain ATCC 3318 was previously considered to belong to the species N. asteroides, but recent studies have shown that this organism, together with other clinical and soil isolates, forms an independent species for which the designation N. farcinica was revived [18-21]. It differs from N. asteroides in some morphological and physiological characteristics (e.g., utilising rhamnose as sole carbon sources) that can be used for identification when the genus affiliation has been determined by chemotaxonomic tests [9]. There are several studies on the in vitro susceptibility of Nocardia species, particularly of N. asteroides, and different susceptibility patterns may also be used to identify the species [9,13]. Our isolate showed resistance against gentamicin, a criterion usually employed to distinguish N. farcinica from N. asteroides [11].
The therapy of brain abscesses usually requires surgery (aspiration or excision) and the application of antimicrobial agents (e.g. penicillin, metronidazole, vancomycin, third-generation cephalosporins, and clindamycin). Both penetration of the blood-brain barrier and entry into abscesses themselves have to be considered in selecting the antimicrobial agents. In this case, surgery could not be performed because of multiple abscesses, partly at inaccessible locations, and due to elevated intracranial pressure with the ensuing risk of herniation into the incisura tentorii. Antimicrobial management consisted of clindamycin, ceftazidime, pyrimethamine, and acyclovir initially. Because of lack of clinical improvement the regimen was changed to a combination of flucloxacillin, metronidazole, amphotericin B, and flucytosine. There was no improvement, however, even when ciprofloxacin was added, and the patient died. In the therapy of Nocardia infection, sulphonamides were used as drugs of choice until recently [22]. However, several recent in-vitro and in-vivo studies have shown that amikacin, imipenem, and, in certain cases, amoxycillin plus clavulanic acid are very active antimicrobial agents in the therapy of nocardiosis [13,23-26]. Dietlein et al reported on a case of brain abscesses caused by N. farcinica [7]. This isolate was susceptible against amikacin and imipenem in vitro. Other antimicrobial agents, such as co-trimoxazole, ampicillin, gentamicin, clindamycin, and vancomycin were not active in vitro. Therapy with amikacin and imipenem led to abscess reduction, but withdrawal was followed by a relapse. Our isolate was only susceptible to amikacin, but showed intermediate susceptibility or resistance to all other antimicrobial agents tested. In view of the observed resistance patterns of N. farcinica, amikacin in
CNS Infection Caused by N. farcinica
213
combination with imipenem or amoxicillin plus clavula- References nic acid seems to be the treatment of choice for such 1. Rubin RH. Infection in the renal and liver transplant patient. In: infections. In this case, amikacin was not used for Rubin RH, Young LS Clinical Approach To Infection In The antimicrobial management. We had several reasons for Compromised Host. 2nd edn. Plenum Publishing New York, this decision: (a) brain biopsy lacked the nocardiosis 1988: 557-621 lesions and the causative pathogen could not be iso- 2. Holm P. Seven cases of human nocardiosis caused by Nocardia Sabowaudia 1975; 13: 161-169 lated; (b) aminoglycosides do not readily cross the 3. farcinica. Tsukamura M, Ohta M. Nocardia farcinica as a pathogen of lung blood-brain barrier and must be given at greater doses infection. Microbiol Immunol 1980; 24: 237-241 for treatment of CNS infections; (c) the well-known 4. Tsukamura M. Nocardia recently caused lung infection in Japan Nocardia asteroides and Nocardia farcinica. Microbiol Immunol nephrotoxicity of aminoglycosides restricts their use in 1988; 26: 341-345 renal transplant recipients, especially in view of a 5. Tsukamura M, Shimoide H, Kaneda K et al. A case of lung infection caused by an unusual strain of Nocardia farcinica. supposed rejection reaction; (d) infections with multireMicrobiol Immunol 1988; 32: 541-546 sistant N. farcinica have been reported rarely. 6. Yoshino K, Kusajima K, Fujisaki T et al. Two cases of pulmonary N. asteroides and N. farcinica most commonly infect nocardiosis by Nocardia farcinica. Jpn J Chest Dis 1988; 47: 617623 man via the respiratory tract [15]. But pulmonary Dietlein E, Firsching R, Peters. Therapie eines Hirnabszesses, involvement may be quite weak and short. In the 7. verursacht durch Nocardia farcinica. Med Klin 1988; 83: 613-623 present case, there existed a progressive bronchopneu- 8. Schaal KP. Actinomyces as human pathogens. In: Okami Y, Bepu T, Ogawara H. Biology of actinomycetes '88. Proceedings of the monia caused by CMV. Despite a very intensive search, 7th International Symposium on Biology of Actinomycetes. Japan we could not find any nocardiosis-like lesion in the lungs Scientific Societies Press, Tokyo, 1988: 277-282 or in the bronchial system. Another possibility may be a 9. Schaal KP. Identification of clinically significant actinomycetes and related bacteria using chemical techniques. In: Goodfellow traumatic introduction of the bacterium [15], but this M, Minnikin D E , Chemical Methods In Bacterial Systematic^. pathway could not be verified. Academic Press, Orlando, New York, London, 1985: 359-381 Whether symptoms which had developed 4 weeks 10. Schaal KP. Laboratory diagnosis of actinomycete disease. In: before the patient's final hospitalisation have to be Goodfellow M, Modarski M, Williams ST, The Biology Of The Actinomycetes. Academic Press, London, New York, San Franinterpreted as a manifestation of nocardiosis remains cisco, 1984: 425-456 speculative. If so, this case of nocardiosis developed 11. Schaal KP. Nocardia, Actinomadura, and Streptomyces, In: Seligwithout clear and continuous symptoms of CNS son D , v Graevenitz A. CRC Handbook Series On Clinical Microbiology, Vol. 1. CRC Press, Cleveland, 1977: 131-144 infection over a long period of time. Our case suggests M, Lechavalier MP. Genus Nocardia Trevisan 1889, that diagnostic procedures such as CCT or NMRT 12. 9.Goodfellow In: Sneath PHA, Mair NS, Sharpe ME, Holt JG, Bergey's should be employed when non-specific symptoms (e.g. Manual Of Systematic Bacteriology, Vol. 2. Wiliams and Wilkins, Baltimore, London, Los Angeles, Sidney, 1986: 1459-1471 nausea and vomiting) occur that may be due to CNS Schaal KP, Schuett-Gerowitt H, Goldmann A. In vitro and in vivo affection. The demonstration of lesions allows the 13. studies on the efficacy of various antimicrobial agents in the initiation of invasive diagnostic procedures including treatment of human nocardiosis. In: Szab6 G, Bird S, Goodfellow M, Biological Biochemical, and Biomedical Aspects of Actinomyspecimen collection for microbiological examination, so Part B. Academiai Kiad6, Budapest, 1986: 619-633 that the appropriate therapy can be started sufficiently 14. cetes, Gordon MA. Aerobic pathogenic actinomycetaceae In: Lennette early. EH, Balows A, Hausler WJ Jr, Shadomy HJ, ed, Manual Of Clinical Microbiology. 4th edn. ASM, Washington DC, 1985: In conclusion, among the bacterial pathogens of brain 249-262 ' . abscesses in immunocompromised hosts, Nocardia spe- 15. Lerner PI. Nocadia species. In: Mandall GL, Douglas RG Jr, cies should be given particular consideration. Renal Bennett JE, Principles and Practice of Infectious Diseases. 3rd edn. Churchill Livingstone, New York, Edinburgh, London, transplant recipients are notably prone to nocardiosis. 1990: 1926-1932 There are nocardiae, e.g. N. farcinica, that are resistant 16. Melbourne, Nocard E. Note sur la maladie des boefs de la Guadaloupe connue against most antimicrobial agents, but therapy with sous le nom de farcin. Ann Inst Pasteur (Paris) 1888; 2: 293-302 amikacin in combination with imipenem or amoxycillin 17. Trevisan V. I generic le species delle Batteriacee. Milano 1889. Reproduced in Int Bull Bacterial Nomencl Taxon 1952; 2:13 plus clavulanic acid is successfully used. Therefore, 18. Tsukamura M. Numerical taxonomy of the genus Nocardia. J Gen these antimicrobial agents should be considered in Microbiol 1969; 56: 265-287 therapy of brain abscesses in renal transplant recipients 19. Ridell M, Taxonomic studies of Nocardia farcinica using serological and physiological characters. IntJSyst Bacteriol 1975; 25:124despite potential nephrotoxic side-effects. 132 Although reported only rarely thus far, N. farcinica 20. Tsukamura M. Extended numerical taxonomy study of Nocardia. Int J Syst Bacteriol 1977; 27: 311-323 may become a more important cause of nocardiosis in the future; it has therefore to be kept in mind, particu- 21. Schaal KP, Reutersberg H. Numerical taxonomy of Nocardia asteroides. Zeutralbl Bacteriol Microbiol Hyg 1. Abt 1978; [Suppl larly in view of its resistance to most antimicrobial 6]: 417-427 22. Peabody JW, Seabury JH. Actinomycosis and nocardiosis. Am J agents. Acknowledgements. We thank Ms Birgit Koch for her skilful assistance isolating the nocardia and Ms Monika Busch for expert performance of the chemical and physiological analysis.
Med 1960; 28: 99-115 23. Dalaviso JR, Pankey GA. In vitro suceptibility of Nocardia asteroides to amikacin. Antimicrob Agents Chemother 1978; 13:
128-129
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214 24. Gombert ME. Susceptibility of Nocardia asteroid.es to various antibiotics, including newer (Madams, trimethoprim-sulfamethoxazole, amikacin, and N-formimidoyl thienamycin. Antimicrob Agents Chemother 1982; 21: 1011-1012 25. Wallace RJ Jr, Septimus EJ, Musher DM et al. Treatment of
experimental nocardiosis in mice: Comparison of amikacin and sulfonamides. J Infect Dis 1979; 140: 244-248 26. Goldstein FW, Hautefort B, Acar JF. Amikacin-containing regimens for treatment of nocardiosis in immunocompromised patients. Eur J Clin Microbiol 1987; 6: 198-200
Received for publication 20.6.90 Accepted in revised form 26.10.90
Nephrology Dialysis Transplantation
Case Report Disseminated Infection of the Central Nervous System Caused by Nocardia farcinica K. Miksits1, G. Stoltenburg2, H.-H. Neumayer3, H. Spiegel4, K. P. Schaal5, J. Cervos-Navarro2, A. Distler3, H. Stein4 and H. Hahn1 'Institut fur Medizinische Mikrobiologie und Infektionsimmunologie der FU Berlin; 2Abteilung fur Neuropathologie im Klinikum Steglitz der FU Berlin; 3Medizinische Klinik und Poliklinik im Klinikum Steglitz der FU Berlin, 4Abteilung fur Pathologie im Klinikum Steglitz der FU Berlin; 5Institut fur Medizinische Mikrobiologie und Immunologie der Universitat Bonn, Germany
Key words: CNS infection; Immunocompromised host; neoformans, T. gondii, and Nocardia species, e.g. Nocardiosis; Nocardia farcinica; Renal transplant reci- N. asteroid.es [1]. Here we report on a renal transplant recipient in pient whom multiple brain abscesses were caused by N. farcinica; it is the first case of that infection in this transplantation unit. This organism has been described as a human pathogen in 56 cases of infection since it has Introduction regained its formal standing in taxonomy and nomenclaDuring the last two decades renal transplantation has ture between 1969 and 1978 [2-8]. In addition, it is become the treatment of choice in patients with chronic apparently isolated from compromised hosts with renal failure. Immunosuppressive therapy, albeit increasing frequency: in the last 3 months, we could necessary, results in a greater susceptibility of the isolate this pathogen from three different patients (idenrecipient to infectious diseases [1]. Infections of the tification performed by Professor K. P. Schaal; unpubcentral nervous system (CNS), such as meningitis, lished data). meningoencephalitis, and brain abscesses are a major cause of morbidity and mortality in renal transplant recipients [1]. In the immunocompromised host they are Case Report usually caused by microorganisms different from those found in the general population [1]. Acute meningitis A 55-year-old female renal allograft recipient (donor is commonly caused by L. monocytogenes, whereas CMV-antibody-positive) was admitted to the Klinikum C. neoformans results in a more chronic course. Menin- Steglitz with a 1-week history of nausea, vomiting and goencephalitis is frequently caused by viruses, e.g. headache. The presence of cytotoxic antibodies and a papovaviruses. Brain abscesses in renal transplant successfully treated rejection reaction necessitated recipients are typically caused by Aspergillus species, irnmunsuppression by a triple-drug therapy consisting of but are also frequently due to L. monocytogenes, C. low-dose a-methylprednisolone, cyclosporin A, and azathioprine since transplantation 8 months ago. One Correspondence and offprint requests to: Dr Klaus Miksits, Institut fur month before the actual admission, the patient had Medizinische Mikrobiologie und Infektionsimmunologie der FU already been hospitalised for nausea, vomiting, and Berlin, Hindenburgdamm 27, D(W)-1000 Berlin 45, Geamany.
K. Miksits et al
210 Cyclosporin A Methylprednisolone Azathioprine PyrimethamiDe Acyclovir
Clindamycln Ceftazldime FlucloxaciHtn Metronldazole Ciprofloxacln Amphoterlcln B Flucytoslne body temperature/°C 40 -
200 ^ diagnostic procedures days
p.5 fl7 (19 |21 |23 [25 (27 (29 pi |33 p5 |37 Died
CCT: cranial computed tomography NMRT: nuclear magnetic resonance tomography biopsy: brain biopsy via burr hole CM-CCT: cranial computed tomography with using contrast medium HE* haemodialysis BS: bronchoscopy [7H period at Intensive care unit Fig. 1. Clinical course of CNS-infection caused by Nocardia farcinica.
fever. With regard to repeated urinary tract infections after transplantation, but despite the lack of any significant microbiological findings, an urosepsis was diagnosed. Treatment with cefotaxime improved the patient's physical condition and so medical care was continued on an outpatient basis. A chest X-ray did not reveal any pathological changes; a cranial computed tomography (CCT) was not performed. The clinical examination now revealed tiredness, a fine tremor of the hands, and intermittent myocloni of
the legs. The major findings were signs of meningeal irritation. CCT both without and with contrast medium, and nuclear magnetic resonance tomography (NMRT) showed multiple intracerebral processes thought to be abscesses (Figs 1, 2a). Signs of increased intracranial pressure necessitated the cancellation of a lumbar puncture. A brain biopsy revealed a lymphocytic-plasmacytic-histiocytic infiltrate considered to be indicative of subacute encephalitis. Neither bacteria (a complete microbiological examination was performed, including
CNS Infection Caused by N. farcinica
a thioglycollate broth culture and a blood agar culture incubating for 10 days) nor other microorganisms (e.g. T. gondii, CMV, HIV, or fungi) could be demonstrated in these biopsies. The only evidence indicative of infection was the serological demonstration of IgM antibodies to CMV. Based on clinical and radiological findings, an antimicrobial therapy was initiated, including pyrimethamine, acyclovir, clindamycin, and ceftazidime. Because of the deterioration of the physical condition despite this treatment, the antimicrobial regimen was changed toflucloxacillin,metronidazole, ciprofloxacin, pyrimethamine, amphotericin B, and flucytosine (Fig. 1). Subsequently the patient became increasingly somnolent and showed an increase in body temperature as well as a reduction of renal allograft function (determined by serum creatinine concentration). Therefore she underwent haemodialysis (Fig. 1). An angiodynography showed a missed diastolic flow as a sign of rejection or toxic renal injury. The most spectacular symptom during this period was intensive hyperventilation. Chest X-rays revealed progressive bronchopneumonia but no microbial pathogen could be isolated. Concomitant signs of persistent and progressive elevation of intracranial pressure made it impossible to repeat brain biopsy or to perform other neurosurgical invasive procedures. Increasing loss of consciousness and steady increase in intracranial pressure together with signs of axial herniation led to coma, despite recovery of allograft function and receding of the radiological signs of bronchopneumonia. Thirtyseven days after admission, brain death was diagnosed (Fig. 1). The pathological examination revealed the following findings: The lungs showed a mild bronchopneumonia caused by CMV, which was demonstrated by staining with a monoclonal antibody and a DNA probe. The kidneys were completely atrophic. In the allograft, there were only isolated signs of tubular necrosis, but no findings indicative of a severe rejection reaction could be demonstrated. Brain volume was increased, as shown by tonsillar coning. The cisterns on the brain base were filled with creamy pus. Leptomeninges on the surface of the spinal cord showed scattered foci of white adherent spheroids (Fig. 2f). Gross appearance on horizontal sections showed lesions - multiple abscesses - corresponding to CCT and NMRT findings (Fig. 2a, b). The stereotactic biopsy was accidentally taken from brain tissue between two abscess holes so that only chronic inflammatory change and no specific pattern or bacteria could be found by special staining in this region. The abscesses in the right cerebellar hemisphere were
211
2f
Fig. 2. Radiological and pathological signs of nocardiosis. (a) NMRT scan of structures of posterior fossa: two encapsulated abscesses with surrounding oedema in the right cerebellar hemisphere; (b) autopsy specimen of corresponding level of brain stem and cerebellum: note abscess cavities in the cerebellum and haemorrhagic necroses of inferior olives; (c) Grocott impregnation (x200): abundant masses of nocardia along the border of the intact brain tissue; (d) Grocott impregnation (xSOO): typically black threadlike structures; (e) meningitis and vasculitis in the meninges of lower brain stem (H&E, X200); (f) caudal portion of the spinal cord: multiple granulomas in the leptomeninges.
filled with necrotic material. Grocott impregnation revealed typically threadlike structures darkly stained black at the border of the abscesses and surrounding tissue (Fig. 2c, d). Most remarkable was the involvement of vessels in the inflammatory process which caused microcirculatory disturbances and haemorrhagic necrosis in the olives (Fig. 2e). These black threadlike structures were also detected in the border zone of all other abscesses and in the inner and outer cerebral spine fluid space.
212
Microbiological evaluation revealed these as N. farcinica, susceptible to amikacin only. Identification was achieved using the methods and criteria described by Schaal, and Goodfellow and Lechevalier [9-12]. These included chemotaxonomic tests (demonstration of mesodiaminopimelic acid in whole-cell hydrolysates and mycolic acid analysis), utilisation tests with a variety of carbon and carbon plus nitrogen sources, as well as more traditional hydrolysis tests [9-11]. The strain contained mesodiaminopimelic acid and mycolic acids giving single spots on thin-layer plates identical to that of typical nocardiae. On the basis of these results, the organism could definitely be assigned to the genus Nocardia. In the utilisation tests, the organism grew well on 2,3-butylene glycol, 1,2-propylene glycol, and L-rhamnose, but not adonitol, L-arabiose, benzoate, citrate, sodium gluconate, mesoinositol, D-mannitol, D-sorbitol or D-xylose as sole carbon sources. It did not utilise gelatin and L-serine as sole N+C sources. Esculin hydrolysis and urease activity were positive; testosterone, but not casein, tyrosine, xanthine, hypoxanthine, or adenine were degraded. This pattern of physiological reactions clearly showed the organism to belong to the species N. farcinica and distinguished it from N. asteroides as currently defined. Furthermore, the strain was resistant to all the aminoglycosides except amikacin, to penicillins and cephalosporins as well as to vancomycin, which is in accordance with the susceptibility data published for N. farcinica [13].
Discussion Nocardia species, a major cause of brain abscesses in immunocompromised hosts, are branched filamentous bacteria that form a fugacious mycelium that tends to break up into rod-shaped or coccoid elements. They are Gram-positive, but may stain irregularly. Some strains are weakly and partially acid-fast [12,14,15]. Blood agar is a satisfactory medium for primary isolation but colony formation takes 4-10 days, while subcultures grow after 48 h of incubation. Therefore, the microbiological laboratory must be informed about suspected nocardiosis to extend the routine incubation period. Colonies may show an off-white, grey, yellow, orange, pink, peach, red, tan, brown, or purple pigmentation and some cultures emanate a musty odour [12,14,15]. N. farcinica colonies are usually orange with sparse to moderate white aerial hyphae. N. farcinica was first described by Nocard in 1888 as the causative agent of bovine farcy in the West Indies [16]. Trevisian gave the designation Nocardia to this genus and nanied the species N. farcinica [17]. Nocard's original isolate is represented by two supposed identical, but actually very different strains in two culture
K. Miksits et al
collections, ATCC 3318 and NCTC 4524 [12]. One of them [ATCC 3318) is a typical nocardia, whereas the second one (NCTC 4524) contains mycolic acids and mycosides characteristic of mycobacteria. Strain ATCC 3318 was previously considered to belong to the species N. asteroides, but recent studies have shown that this organism, together with other clinical and soil isolates, forms an independent species for which the designation N. farcinica was revived [18-21]. It differs from N. asteroides in some morphological and physiological characteristics (e.g., utilising rhamnose as sole carbon sources) that can be used for identification when the genus affiliation has been determined by chemotaxonomic tests [9]. There are several studies on the in vitro susceptibility of Nocardia species, particularly of N. asteroides, and different susceptibility patterns may also be used to identify the species [9,13]. Our isolate showed resistance against gentamicin, a criterion usually employed to distinguish N. farcinica from N. asteroides [11].
The therapy of brain abscesses usually requires surgery (aspiration or excision) and the application of antimicrobial agents (e.g. penicillin, metronidazole, vancomycin, third-generation cephalosporins, and clindamycin). Both penetration of the blood-brain barrier and entry into abscesses themselves have to be considered in selecting the antimicrobial agents. In this case, surgery could not be performed because of multiple abscesses, partly at inaccessible locations, and due to elevated intracranial pressure with the ensuing risk of herniation into the incisura tentorii. Antimicrobial management consisted of clindamycin, ceftazidime, pyrimethamine, and acyclovir initially. Because of lack of clinical improvement the regimen was changed to a combination of flucloxacillin, metronidazole, amphotericin B, and flucytosine. There was no improvement, however, even when ciprofloxacin was added, and the patient died. In the therapy of Nocardia infection, sulphonamides were used as drugs of choice until recently [22]. However, several recent in-vitro and in-vivo studies have shown that amikacin, imipenem, and, in certain cases, amoxycillin plus clavulanic acid are very active antimicrobial agents in the therapy of nocardiosis [13,23-26]. Dietlein et al reported on a case of brain abscesses caused by N. farcinica [7]. This isolate was susceptible against amikacin and imipenem in vitro. Other antimicrobial agents, such as co-trimoxazole, ampicillin, gentamicin, clindamycin, and vancomycin were not active in vitro. Therapy with amikacin and imipenem led to abscess reduction, but withdrawal was followed by a relapse. Our isolate was only susceptible to amikacin, but showed intermediate susceptibility or resistance to all other antimicrobial agents tested. In view of the observed resistance patterns of N. farcinica, amikacin in
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combination with imipenem or amoxicillin plus clavula- References nic acid seems to be the treatment of choice for such 1. Rubin RH. Infection in the renal and liver transplant patient. In: infections. In this case, amikacin was not used for Rubin RH, Young LS Clinical Approach To Infection In The antimicrobial management. We had several reasons for Compromised Host. 2nd edn. Plenum Publishing New York, this decision: (a) brain biopsy lacked the nocardiosis 1988: 557-621 lesions and the causative pathogen could not be iso- 2. Holm P. Seven cases of human nocardiosis caused by Nocardia Sabowaudia 1975; 13: 161-169 lated; (b) aminoglycosides do not readily cross the 3. farcinica. Tsukamura M, Ohta M. Nocardia farcinica as a pathogen of lung blood-brain barrier and must be given at greater doses infection. Microbiol Immunol 1980; 24: 237-241 for treatment of CNS infections; (c) the well-known 4. Tsukamura M. 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Received for publication 20.6.90 Accepted in revised form 26.10.90
