Postgrad Med J: first published as 10.1136/pgmj.52.610.497 on 1 August 1976. Downloaded from Postgraduate Medical Journal (August 1976) 52, 497-500. Pneumococcal antigen in pneumonia. A post-mortem study with the histological and bacteriological findings M. EL-REFAIE R. TAIT M.B., D.M.Sc. M.B., B.A.O. C. DULAKE* F. E. DISCHE M.B., M.R.C.Path., Dip. Bact. M.D., M.R.C.P., F.R.C.Path. Public Health Laboratory, Dulwich Hovpital, and Department of Morbid Anatomy, King's College Hospital Summary and the presence of pneumococcal capsular antigen Pneumococcal capsular antigens can be detected in has been correlated with the histological and bac- lung tissue by counter-current immunoelectrophoresis teriological findings. even when, following antibiotics, post-mortem bac- teriology suggests that Escherichia coli has replaced Materials and methods pneumococci. Post-mortem examinations The results suggest that antipneumococcal therapy Forty-five postmortems, performed at King's Protected by copyright. would benefit at least 55% of patients critically ill College and Dulwich Hospitals during the period with lung infection and that the potentially toxic January-March, 1975, were studied. Post-mortem drugs directed at coliform bacteria may be unneces- examinations were usually conducted within 24-48 hr sary. of death; ten were delayed for 72 hr. The bodies were kept at 40C until examined. Details of age, clinical findings, and antibiotic treatment during the patient's Introduction last stay in hospital, were extracted from the hos- Pneumonia is a common condition in seriously ill pital records. patients and is a frequent cause of death. Since the introduction of antibiotics, post-mortem lung studies Lung specimens have shown a striking change in the bacteriology of In each case the lungs were carefully examined for terminal pneumonia. The pneumococcus, formerly areas of consolidation from which a piece (approxi- the pathogen isolated from most post-mortem lung mately 10 g) was removed under aseptic precautions. http://pmj.bmj.com/ cultures (Smillie and Duerschner, 1947), is rarely Patchy consolidation was a common finding; and isolated nowadays, instead other bacteria, mainly healthy as well as affected tissue might be contained coliform bacilli, are found (Kneeland and Price, in the pieces removed. When there was no apparent 1960; Tanner et al., 1969). Clinicians now regard consolidation, a sub-pleural piece was taken from these as important lung pathogens, and patients are the lower lobe. Lung specimens were studied histo- often treated with potentially toxic chemothera- logically and bacteriologically and tested for pneumo- peutics. How much of the change in the bacteriology coccal capsular antigen. of terminal pneumonia is of importance has not been on September 30, 2021 by guest. proved. Culture Since the pneumococcus causes lung inflam- Precautions were taken to reduce surface con- mation and is suppressed by antibiotic therapy, taminants before culture. The lung specimen was first detection of its capsular antigen may be taken as washed with sterile saline, placed in boiling water for evidence of infection by the organism (El-Refaie and 10 sec, and then ground in a sterile tube and plated Dulake, 1975). In this study, the role of the pneumo- on blood agar, chocolate blood agar, and Mac- coccus in terminal pneumonia is re-assessed; the Conkey's agar. The plates were incubated aerobically technique of counter-current immunoelectrophoresis overnight at 370C; chocolate blood agar plates being has been applied to a series of post-mortem lungs in 10% carbon dioxide atmosphere. Organisms were * Correspondence: Dr C. Dulake, Public Health Labora- identified using the methods of Cowan and Steel tory, Dulwich Hospital, East Dulwich Grove, London S.E. (1965). Scanty growth of saprophytic species (less 22. than 10 colonies/plate) was ignored. 498 M. El-Refaie et al. Postgrad Med J: first published as 10.1136/pgmj.52.610.497 on 1 August 1976. Downloaded from Counter-current immunoelectrophoresis (CIE) The presence of the antigen correlated with pneu- CIE was carried out in 1 % agarose using a dis- monia: eleven of fourteen antigen-positive specimens continuous veronal-acetate buffer system (El-Refaie showed acute pneumonic inflammation. and Dulake, 1975). Ground lung tissue was boiled in Table 3 gives details of the cases with antigen- 2 ml of sterile water for 15 min, then centrifuged and positive lung specimens. A total of twenty-one types the supernatant tested. Danish antisera were used of capsular antigen was identified. Types 3 and 32 (Lund, 1963); and all bacterial isolates were care- were found more commonly and each was present fully tested for the production of cross-reacting in three specimens. In general, capsular types 1-10 antigens. inclusive were less frequently encountered than types 11-48; the latter represented 67 % (fourteen of Results twenty-one) of the types identified. Cross-reaction There were forty-three adults (average age 65 was observed only once between type 41 and a years), one infant, and a still-born fetus. Cardio- strain of Escherichia coli in case 45. vascular disease was present in nineteen cases, malignant tumour in fifteen, renal and liver failure Discussion each in three cases, and rheumatoid arthritis, peri- Using counter-current immunoelectrophoresis it tonitis and acute gasteroenteritis in the remaining was possible to identify the polysaccharide capsular five. More than two-thirds of the adult patients had antigen of the pneumococcus in 55 % (eleven of had antibiotics during their illness. twenty) of lungs showing histological evidence of Table I lists the organisms isolated from inflamed acute pneumonia. The presence of occasional poly- and non-inflamed lungs. In both cases the growth morphs in one of the specimens showing chronic was usually mixed and, in thirty of thirty-eight inflammatory changes may indicate a recent pneu- instances, formed mainly of coliform bacilli. Most monic process. It appears, therefore, that theProtected by copyright. of the species were equally distributed between both incidence of pneumococcal terminal pneumonia groups. There was no pneumococcal growth; and determined by antigen detection is 60%. sterile cultures were found in nineteen instances, The presence of the antigen correlated strongly eight of them from cases with inflammation. with pneumonia (Table 2). The finding of the antigen Table 2 shows the results of the histological in one of the twenty specimens without inflammation examination of lung specimens and correlates these probably represents a spill-over of the antigen from with the finding of pneumococcal capsular antigen. a nearby undetected pneumonic focus or can be TABLE 1. Bacteriological and CIE findings in forty-five unselected post-mortem lung specimens Lung inflammation Findings Present (twenty-five cases) Absent (twenty cases) Bacterial growth * http://pmj.bmj.com/ E. coli 11 (44%Y) 6 (30%) Klebsiella spp. 2 ( 8%) 0 ( 0%4) Enterobacter aerogenes 2 ( 8%Y.) 3 (15%o) Proteus spp. 4 (16%4) 2 (10%) Strep. faecalis 2 ( 8%Y.) 1 ( 5%) Staph. aureus 2 ( 8%4) I ( 5%) Staph. albus 1 ( 4%Y) 1 ( 5%) No bacterial growth 8 (32%) 11 (55%) on September 30, 2021 by guest. Pneumococcal antigen 13 (52%) 1 ( 5%) * Mostly from mixed culture. TABLE 2. Correlation of histology with pneumococcal antigen in forty-five unselected post-mortem lung specimens Lung histology Antigen present Antigen absent Acute pneumonia (twenty cases) 11 9 Chronic inflammatory changes * (five cases) 2 3 No evidence of inflammation (twenty cases) 1 19 Total (forty-five cases) 14 31 * Chronic inflammatory cells with or without fibrosis. Pneumococcal antigen in pneumonia 499 Postgrad Med J: first published as 10.1136/pgmj.52.610.497 on 1 August 1976. Downloaded from C)~~~~~~~~~~~~~N tn 0) ea£^ ^ > > >~~~~00 t f fien C) PLO c~o en en +++I+ ;~+++++ I++++ 2~~~~~~~~~~~~~~~~20@=\o~ 3a==ri 0~~~~~~~~~~~~z C3 t: U U ! " u4 0~~~~~~~~~~~~ Protected by copyright. 0 °° w 0. 2 ~~.~~~~Co~ ~ etDSs.c E~~e , .e , .2 ACu U) 0~~~~ 0 v a) a- N^^^ http://pmj.bmj.com/ ~~~* 0d 0 > E. CU UCC Cu0 C C Cd Cu 0000S. d00 0 a)~~~ a) 0"0 0" ~~.20:£ 0 0 0Cu 0 a)o.0F 0 .-.-0 0 F0 E U.UA U U on September 30, 2021 by guest. Cu a aot-0 0 r r- Cu ,o~"o o a C) ceo~~~~~cUu)0u o m 0 t e o ) c;00 %n 00 a)C Cna) a) Cu C m) C u C U 500 M. El-Refaie et al. Postgrad Med J: first published as 10.1136/pgmj.52.610.497 on 1 August 1976. Downloaded from attributed to the inclusion of healthy tissue in the by pneumococcal infection and the E. coli played no histologically studied lung specimens. active part in the infection or at most invaded Two points had to be considered in interpreting already damaged tissue. the findings. Firstly, it might be antigen derived In addition to prior antibiotic therapy, changes in from commensal pneumococci that was being detec- the body flora occurring shortly before or after death ted. However, the results show the close association may modify the bacterial picture of post-mortem between lung inflammation and the presence of the lung cultures. The present data (Table 1) and those antigen indicating the discriminant nature of the of earlier workers (e.g. Kneeland and Price, 1960) technique used. Secondly, antigenic overlap oc- show that E. coli can be isolated from normal lung casionally occurs between coliform bacteria and tissue at post-mortem. pneumococci. Evidence of cross-reactions was ob- In conclusion, the study suggests that pneumo- served only once between antigen type 41 and a coccal lung infection in patients with chronic or strain of E. coli in case 45 (Table 3). systemic disease is as important today as it was In this study, the presence of more than one cap- before the introduction of antimicrobials and that sular antigen in five of the inflamed lungs can be post-mortem bacteriology is highly questionable in explained by the carriage of more than one pneumo- assessing the role of different lung pathogens.