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摘要:目的 描述Buruli溃疡的病理、病原体的形态特征以及治疗特点，以提高对本病的认识。 方法 复习有关文献，根据临床和病理分析6例下肢及上肢慢性溃疡病人，按照WHO诊断标准作出临床诊断，并皆经病理和PCR检测证实。溃疡采用切除加植皮术治疗。 结果 5例单发溃疡中左下肢4例，右下肢1例。1例为多发溃疡，病变位于左右下肢及左食指。溃疡直径2.5～6.5cm，平均3.2cm。其特点是皮肤及皮下组织坏死，边缘呈潜行性，底部有黄色坏死物覆盖。溃疡周围皮肤水肿和色素沉着。显微镜下见到细胞外有散在或成团的抗酸杆菌和坏死脂肪细胞—“鬼影细胞”。抗结核药物和抗生素对本组Buruli溃疡无较，5例行手术切除溃疡加植皮术或清创术，除1例复发外，4例治疗效果良好。另1例行清创术换药后溃疡愈合。 结论 Buruli溃疡可以在我国的亚热带地区发生，因此当遇到久经不愈的慢性皮肤溃疡时，要考虑患有Buruli溃疡的可能性。外科手术仍然是目前治疗Buruli溃疡的主要方法。
关键词:溃疡分支杆菌;皮肤感染;Buruli溃疡;中国
Mycobacterium ulcerans infection（Buruli ulcer）First report of six cases in China with literature review.
ZHOU Xue-lu，TAN Xue-jun，YE Wei-hong，et al.
（Department of Surgery of Dongguan Municipal Hospital of Traditional Medicine，Dong-guan523003，Guangdong，P.R.China）
Abstract:Objective To report the six Mycobacterium ulcerans infections（Buruli ulcer）in China which is the third most com-mon mycobacterial infection in West Africa after tuberculosis and leprosy.with literterature review and to provide sciertific information for diagnosis and treal ment of the disease. Methods Six patients with chronic ulcers in lower or upper extremities were diagnosed clinically，and confirmed either by histopathologically，or by PCR or both，then managed by surgical approach of the six caoes. Results One case was male，one male and five were females，with an averaged age of69years（47～83years）.The clinical mani-festations of the patients were deep，indolent，chronic ulcer with undermined margin in their legs in five cases，and in the legs and left finger in one case.Left side outnumbered right one.The diameter of the ulcer was2.5～6.5cm，averaged3.2cm.The micro-scopic findings in the lesion showed extra-cellular anti-fast bacilli and ghost cells.Anti-tuberculosis drugs and antibiotics have no effectiveness to the patients.Six cases had a satisfactory result except one whe had recurrent ulcer after surgical intervention. Con-clusion Chronic unusual skin lesions.occurred in this country should consider Mycobacterium ulceransinfection Surgery remains the mainstay of potentially curative treatment.
Key words:Mycobacterium ulceran infection，Buruli ulcer，China
1 Introduction
1.1 Buruli ulcer is an emerging infectious disease caused by Mycobacterium ulcerans（M.ulcerans）.The causative organism belongs to the same family of bacteria that cause leprosy and tuberculosis.Buruli ulcer is the third most com-mon mycobacterial infection in non-immunocompromised humans after tuberculosis and leprosy.It often occurs in tropical and subtropical countries around the world ［1］ .Over the past decade，however，there have been reported in-creases in the incidence of Buruli ulcer in West Africa.
1.2 In1998，the World Health Organization（WHO）rec-ognized this disease as a public health problem and efforts are being made to address this disease ［2］ .However，there has been no formal report in China，hence we hope that this report helps to raise the awareness of the disease among clinician，public health officials and the public in China.
2 Materials and methods
Between2003and2004，six cases of chronic limbs ul-cer were referred to our hospital，including a male five fe-males，aged from47to83years with an averaged age of69years.Four patients were farmers，the mate patients worker and another female was a nun.History revealed that there was anteceded traumatic factor in two patients.The averaged duration of hospitalization was one month，and the total fee for hospitalization was estimated at about RMB15，000（US ＄2000）.
Five patients referred had a characteristic unilateral ul-cer in lower extremity，left in four and right in one.Another patient had bilateral ulcer in legs and ulcer in finger simul-taneously.The duration of illness ranged from two to twelvemonths，with averaged7.8months.
The diameter of ulcer varied from2.5cm to6.5cm with averaged3.2cm.The disease often starts as a painless swelling in the skin called a nodule or a papula.After a few weeks，the original lesion characteristically developed skin ulceration with extensive necrosis of subcutaneous fat.Yel-low necrotic slough in the base and undermined ulcer edge were visible.In the absence of secondary bacterial infec-tions，ulcers are painless and fairly”clean”.There was slightly edema and pigmentation in the skin around the le-sion（Figure1（略））.Usually there were no systemic symptoms such as fiver，chill or anorexia.X-rays showed that there was no abnormality in our patients.A biopsy from the ulcer border was taken for histopathological examination.Biopsy specimen showed necrosis in the panniculus and dermis，vasculitis and inflammatory cells.Fat cells enlarge，die and lose their nuclei，but retain cell membranes，so these cells were referred to as ghost cells（Figure2（略））.In the Ziehl-Neelsen（ZN）staining，extracelllar acid-fast bacilli（AFB）were seen scattered and typically arranged in spherules（Figure3（略））.
All the patients were freated with antibiotic for a period of over2weeks and some cases received anti-tuberculosis treatment，but the results was not satisfactory.Five out of the six patients had an excision of the ulcer and skin graft.The excision includes1-2cm healthy tissue at the lateral and deep into the deep fascia.Only one patient had de-bridement and dressing Results
Follow-up ranged from4months to2years by per-sonal examination of the operating surgeon.There was recur-rence in one patient three months after surgical intervention and the other five patients showed satisfactory results without significant postoperative complications or adverse sequelae，including skin necrosis，long-term pain，or deformity.（Table1）Discussions
In1948，MacCallum and his colleagues ［3］ described patients with chronic necrotizing skin ulcers due to infection with M.ulcerans in Victoria，Australia.This was the first published paper on the disease in the medical journal.How-ever，it is believed that Sir Albert Cook described cases consistent with Buruli ulcer in1897in Uganda but this was not published.In Africa，most of the initial reports came from the Buruli County，Mego in1961and consequently named Buruli ulcer after this county reported by Clancey ［4］ .It is estimated that over27countries in Africa，Asia，Amer-icas and Western Pacific region have the disease，in which the prevalence rate of the disease is as high as22% ［5］ .Al-though there has been a report of oversea Chinese woman ［6］ ，as far as we know，however，this is the first report of thedisease in China. Table1 Clinical presentations，histopathological findings and treatment of six Buruli ulcer cases
Up to now，the exact mode of transmission of the dis-ease remains obscured.It is postulated that M.ulcerans is normally a harmless environmental microorganism in tropical rain forests of warm temperate environments.Transmission of the disease to human being may occur when the soil is destroyed by human being or natural events.In such in-stances，M.ulcerans may enter and proliferate in slowing moving or stagnant water，from which it may spread as a naturally generated aerosol.Meyers and others ［7］ have for a long time believed that trauma to the skin may introduce the organism into the skin.The injury may be a minor one and therefore may go unnoticed by the patient or a major one such as needle injection or a gunshotwound.Two of our pa-tients had a history of antecedent trauma at the site of the lesion，so we agree the point that Buruli ulcer may be in-fected by means of trauma.Most of cases of Buruli ulcer have been reported in tropical or subtropical regions around the equator.Dongguan is located around the latitudes22°N.Therefore we are sure there must be existence of this envi-ronmental mycobacterium in this subtropical region;more-over recently many topographical features have been de-stroyed in order to build economic development zone，villas or resorts in Dongguan.These environmental changes may play an essential role in the survival of the etiological agent.
About70%of patients are children under15years of age in Africa ［5］ .Our patients，however，were much older than those in Africa;the averaged age was69years old.Our findings suggest that these old female patients may be related with immunoinsufficiency.Except for one male case，all the patients were female and this result is consistent with other findings that show female patients outnumbered male ones.
There are various forms of presentation by Buruli ul-cer.The earliest form is the nodule but that is hardly seen.
Patients often present late with ulceration.All our cases presented with ulcers but not as extensive as described in other places in Africa.The averaged diameter of the ulcers is3.4cm;this may be associated with the bacterial strain，which produces a little weaker toxin to the tissue ［8］ ?Never-theless these ulcers have the typical features of the disease as described in the literature.
Five out of the six cases had their lesions on the lower limbs;another one on the lower and upper limbs simultane-ously.Almost all of the lower limb lesions were on the left limb.The ankle lesions were the most frequent and perhaps reflect the fact that the organism lives in the soil and the an-kle may be prone to more injuries.
Diagnosis is usually not difficult for heath workers in endemic areas，but in countries with a low incidence，M.ulcerans infection is often not considered and consequently the diagnosis is delayed.Beside the clinical diagnosis，there are four standard methods for laboratory confirmation of clinical diagnosis of Buruli ulcer.The first one is the ZN staining method for AFB.This method is used for the diag-nosis of tuberculosis and leprosy.However，we attempted this method in six cases but none was positive for AFB.Per-haps our method of collecting specimen was inadequate and we believe that standard guidelines on taking the right speci-men could make this method very useful in hospitals in de-veloping countries that have the disease.The second is cul-ture of M.ulcerans.This method requires some expertise and resources that may not be immediately available in rural health facilities.And then the method which comes to histopathological diagnosis is considered the gold standard for the diagnosis M.ulcerans infection ［9，12］ .Although we believe that this service could be available in endemic coun-tries of the developing world，it may not be immediately ac-cessible to most rural hospitals that treat patients with the disease.The last one is the use of modern molecular biolog-ic techniques such as PCR.This can be done in reference laboratories only.Our specimens were confirmed histopatho-logically and by PCR.
Buruli ulcer must be differentiated with those caused by M.tuberculosis and M.leprosy.Unlikely lepromatous leprosy，where clumps of M.leprae are present inside macrophages，M.ulcerans organisms are very rarely intra-cellular ［13］ .Of course，PCR is a reliable way to differenti-ate them.
Surgical procedure remains the mainstay of curative treatment of Buruli ucler nowadays，although some anti-tuberculosis drugs promote healing of preulcerative lesions or early ulcers ［14］ .Early lesions such as nodule，or plaque，or small ulcer less than2cm are excised en bloc，and skin is sutured primarily.However，large ulcers and disseminated nonulcerative lesions are widely excised and sequent skin graft is necessary for prevention of contraction deformi-ties ［9，10］ .Antibiotics are only applied in the patients with secondary infection.
Five of the patients had excision and split-skin graft，one patient had excision only followed by wound dressing.All the cases were done under local anaesthesia.One wom-an had a recurrence three months after surgery，probably owing to insufficient excision，hence the importance of a thorough dissection of the lesion should not be disregarded.The duration of hospitalization for the six patients ranged from two to twelve months，with an average of one month.In other countries，the average hospitalization is in excess of100days.Most of our patient presented earlier.The results also showed that the longer the hospitalization lasted，the higher cost was.The average cost per patient was RMB15，000（US＄2000），which accounted for200%of the aver-age per capita income in this country（US＄1000，2003）.It really imposed an immense burden on the patients and their families.Since this is our first encounter with Buruli ulcer patients，we believe that with time we would be able treat patients better and faster，thus reduce the period of hospitalization further and decrease the socioeconomic bur-den on the patients and the country.
In conclusion，although there is a report from overseas Chinese，this is the first domestic reported case of M.
ulcerans infection in China.These scattered cases in the south of China might be the tip of the iceberg of Buruli ul-cer.The purpose of this article is to pay attention to the possibility in prevalence of M.ulcerans infection in the country.Therefore its extent and public health importance in this country needs further investigation.
Acknowledgements
We really appreciate Professor Francoise Portaels and her colleagues for their excellent PCR work.We also thank Dr.Asiedu Kinsley so much for his great help.
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作者单位:东莞市中医院外科，广东东莞 523003.
作者简介:周学鲁（1957～），男，医学博士，主任医师，研究方向:普通外科、Buruli溃疡.
收稿日期:2005-04-10