Journal of Infection (199o) 20, 83-93
Letters to the Editor Long latency pneumonia:
a case of melioidosis
Accepted for publication 25 May 1989 Sir, We wish to report a case of b r o n c h o p n e u m o n i a due to Pseudomonas pseudomallei, an organism found only in the tropics, in a patient who had not left this country for 2 years. A 6o-year-old Pakistani m a n was sent to the accident and emergency d e p a r t m e n t of this hospital by his doctor, with a history of abdominal pain and malaise lasting 2 weeks. Further history could not be obtained, since the patient did not speak English, and an interpreter was not available. On examination, the patient was found to be febrile (4o °C) and dehydrated. T h e r e were signs of consolidation in the lower lobe of the right lung. Abdominal examination and chest X - r a y were unremarkable. Initial blood tests showed a raised concentration of glucose ( I 5 m m o l / 1 ) , and a low concentration of sodium ( I I S m m o l / 1 ) . T h e concentrations of urea (5:I mmol/1), potassium (3"9 mmol/1), and haemoglobin (14. 5 g/dl) were all within normal limits. A white blood cell count (9"0 x loS/l) and urine microscopy were also normal. Blood was also taken for culture before starting treatment by means of rehydration, sliding scale insulin, and intravenous ampicillin plus gentamicin. By the next morning, the diabetes was controlled and the patient's temperature had fallen to 38 °C. Chest signs, however, were more pronounced. T h e r e was now evidence of bilateral basal consolidation with a rapidly worsening wheeze. D u r i n g the m o r n i n g the patient suffered a cardiopulmonary arrest. H e was resuscitated and taken to the intensive care unit for artificial ventilation. Because of his ethnic origin and because the electrolyte disturbance was similar to that sometimes seen in Legionnaire's disease, antibiotic treatment was changed to erythromycin, rifampicin, isoniazid and streptomycin. Cefuroxime was added later when G r a m - n e g a t i v e rods were seen in the blood cultures taken on admission. D u r i n g the next day the patient remained haemodynamically stable and artificial ventilation maintained good oxygenation. However, his a b d o m e n became distended with shifting dullness on examination. A peritoneal aspirate was heavily bloodstained but sterile. L a p a r o t o m y revealed a large tear in the liver, thought to be a resuscitation injury. Despite massive blood transfusion and inotropic support, the patient died shortly after surgery. P o s t - m o r t e m examination revealed bilateral b r o n c h o p n e u m o n i a but no other evidence of sepsis. T h e organism isolated from the patient's blood was later identified as P. pseudomallei, the causative organism of melioidosis. T h i s identification was confirmed in the Division of Hospital Infection at the Central Public Health Laboratory, Colindale, where a high antibody titre to this organism was also found in the patient's serum. Melioidosis is very rare in the U . K . 1 but its rarity m a y be due partly to unfamiliarity with the disease as well as to its non-specific and variable presentation. 2 Periods of asymptomatic carriage m a y be as long as 26 years thus giving rise to the expression 'Vietnamese t i m e - b o m b ' . 3 Although there are few Vietnamese war veterans in this country, holiday travel to the Far East is increasing so that more cases may be seen. Pseudomonas pseudomallei is classed as a category B pathogen in the U . K . Since mortality from established sepsis exceeds 70 %, even when appropriate treatment is
Letters to the Editor
given, we considered it p r u d e n t to offer prophylactic tetracycline to the patient's family, and to hospital staff who had been most exposed. T h e s e included anaesthetists, staff in the microbiology laboratory, the intensive care unit and the p o s t - m o r t e m room. (We thank Dr T. Pitt for confirming the identity of the organism and for serological tests as well as Dr P. Fleming for permission to report his patient.)
*Department of Microbiology t Department of Medicine Westminster Hospital London S W I P 2AR, U.K.
M. J. Sheppard* R. M. Marriottt T. J. Brown References
I. Peck G. The first case of septicaemic melioidosis in the U.K. Ailed Lab Sci 1986; 43:
855-856. 2. Smith CJ, Allen JC, Noor Embi M, Othman O, Razak N, Ismail G. Human melioidosis; an emerging medical problem, ff Appl Microbiol Biotechnol 1987; 3: 343-366. 3. Greenberg JH. Public health problems relating to the Vietnam returnee. JAMA 1969; 2o7: 697-702.
Antibodies reactive with non-polymorphic epitopes on HLA molecules c a u s e f a l s e - p o s i t i v e H I V a n t i b o d y tests o n A f r i c a n s a m p l e s o f s e r u m
Accepted for publication 6 June 1989 Sir, A very high rate of false-positive results for antibodies to the h u m a n immunodeficiency virus ( H I V ) has been reported in samples of serum from rural non-elite Africans, when purified virus from H9 cells infected with H I V has been used as antigen for the enzyme-linked i m m u n o s o r b e n t assay ( E L I S A ) . T M A good explanation for these findings does~not exist. We have recently reported that antibodies which react with n o n - p o l y m o r p h i c epitopes on H L A molecules, present in patients with hydatid disease, 5 interfere in H I V screening tests, s Our study shows that such a n t i - H L A reactivity correlates closely with false-positive H I V antibody tests done on the serum of Africans. We studied serum samples obtained from 560 ' h e a l t h y ' Africans (396 males and 164 females; mean age, 29 years; range, 20 to 62 years), living in two rural villages of Somalia, namely Mareire and M o o d a - M o o d e , both situated along the Scebeli river. H I V antibodies were detected by means of three different commercial E L I SA kits: Abbott H 9 / H T L V I I I E I A kit, lot lO37-24 (screening test), E n v / C o r e recombinant Escherichia coli E I A Abbott H T L V I I I , lot 2791-22, and Abbott recombinant H I V I E I A , lot 25-257. Tests were performed according to the manufacturer's instructions. Testing for antibody to H L A was p e r f o r m e d by use of purified class I ( R M 2 cell line: A I I, 24; B28, 44; C-; immunological purity 57 %) and class I I ( L g l o cell line: D R 7 , 7; D R w 5 3 ; D Q w 2 ; immunological purity 4 7 % ) radio-iodinated antigenic preparations. 7 T h e reactivities to each labelled antigen were revealed by use of a double antibody technique with goat antiserum to h u m a n immunoglobulin as the precipitating reagent. 8 A serum was considered positive for H L A antibodies when the value obtained for it was greater than the cut-off threshold calculated for a control sample from 50 Somali blood donors living in an urban area [mean + 3 standard deviations (S.DS)].