The influence of three types of preoperative mechanical bowel preparation on colonic microflora has been studied in 88 patients undergoing elective bowel resection and compared with 21 controls. Neither conventional bowel preparation (CBP) using oral magnesium sulphate, enemas and rectal washouts nor whole bowel irrigation (WBI) via a nasogastric tube influenced the type or number of organisms in the colon at the time of operation. The administration of an elemental diet (ED) was associated with only a small reduction in the numbers of Escherichia coli (P <0.02). The addition of oral neomycin and metronidazole for 48 h before operation to all three methods of bowel preparation was associated with a highly significant reduction in the counts per ml of E. coli (P<0.001) and Bacteroides fragilis (P<0.001) in the colon. There was no correlation between the diameter of the lesion being resected with the numbers of bacteria in the colon even when oral neomycin and metronidazole were added to the bowel preparation.

Gastric aspirates were obtained from 12 healthy volunteers, 49 patients with duodenal ulcer, 14 with gastric ulcer and 35 with gastric carcinoma. The mean total viable bacterial counts in these groups were as follows: volunteers 0, duodenal ulcer 3.8 X 10(1), gastric ulcer 6.95 X 10(4), carcinoma 1.9 X 10(7) organisms/ml. The incidence of wound sepsis in patients without antibiotic cover was; duodenal ulcer 17 per cent, gastric ulcer 38 per cent, carcinoma 56 per cent. Regardless of the underlying pathology, patients with counts greater than 5 X 10(6) organisms/ml in the gastric aspirate had a 93 per cent incidence of wound sepsis, compared with 16 per cent in patients with counts of less than 5 X 10(6) organisms/ml (P less than 0.001). In the group with high counts all except one of the wound infections were caused by organisms present in the stomach at the time of operation. There was a good correlation in the bacteriology of apirates obtained during preoperative endoscopy compared with operative nasogastric samples (n = 31) both for viable counts (r = 0.93) and for the counts of individual organisms. Therefore, preoperative endoscopy can be used to identify patients who are at risk of developing wound sepsis after gastric surgery.

rest was instituted and the temperature resolved in 24 hours, while all signs and symptoms disappeared in five days.Subsequent investigations showed no evidence of streptococcal infection (a throat swab grew no pathogens and the antistreptolysin titre was < 125 units/ml both one day after admission and six weeks later).The antibody titre for psittacosis LGV was > 1/1000 on admission and six weeks later was still raised at 1/128.Inquiry later showed that before his illness he had visited regularly a neighbouring house in which a healthy, psittacine bird was kept. DiscussionIn this case there are two major and three minor criteria of rheumatic fever present, but without evidence of a recent streptococcal infection.On the contrary, the presence of a cough and constitutional disturbance associated with patchy shadowing on the chest x-ray film and a signific- ant and changing antibody titre all support a diagnosis of psittacosis.The rashes described in association with this disease include "rose spots,"2 erythema nodosum,2 and a macular scaly rash.3We could find no reports of an exanthem resembling erythema marginatum.Arthritis, which may be migratory,4 is a rare complication of psittacosis in man, though in sheep and cattle polyarthritis it is well recognised.5This case shows that psittacosis may present with minimal respira- tory disturbance and with a clinical picture resembling rheumatic fever with erythema marginatum and polyarthritis.

Twenty-eight patients with histologically proved pseudomembranous colitis have been seen in one hospital since July 1975. All patients with the disease had received antibiotics, six for infections not requiring operations; the other 22 cases all occurred after major surgery. All the patients had diarrhoea; six patients also had fever with clinical signs of sepsis, and three had abdominal pain thought to be due to anastomotic dehiscence after colonic resection. Pseudomembranous colitis was associated with white blood counts over 15 000/mm3 in 17 patients and albumin concentrations of less than 30 g/1 in 18. Pseudomembranous colitis was an incidental finding at necropsy in two of six patients who had not had an operation. Of the 22 patients who had had major surgery, nine died from this complication; in all except two of these cases the diagnosis was made only at necropsy. If pseudomembranous colitis is suspected on clinical grounds or if there is an unexplained complication after colorectal surgery repeat sigmoidoscopy and testing for faecal toxins should be carried out to establish the diagnosis so that prompt supportive treatment can be given.

The microflora of the jejunum, ileum, and colon has been studied from operative samples in Crohn's disease (n = 30), ulcerative colitis (n = 15), and controls (n = 40). There was no significant difference in the flora of patients with ulcerative colitis compared with controls. In Crohn's disease there was a significant increase in E. coli (P less than 0.001) and B. fragilis (P less than 0.001) in the ileum and of E. coli (P less than 0.001) and lactobacilli (P less than 0.01) in the colon. The abnormal ileal flora in Crohn's disease was unrelated to serological evidence of disease activity (indices: ESR, serum albumin, serum seromucoids), diameter of the ileum, or excision of the ileocaecal valve. The abnormal colonic flora in Crohn's disease was not related to presence of macroscopic colitis.

The influence on colonic microflora of neomycin and metronidazole alone, or in combination, was studied in volunteers taking a normal diet. Bacterial counts on daily faecal samples revealed that metronidazole had no influence on anaerobic faecal bacteria. Neomycin on the other hand, was effective against sensitive aerobes. However, the combination of neomycin and metronidazole profoundly reduced both aerobic and bacteria. Assay of faecal antibiotic concentrations showed that neomycin achieved high intraluminal levels while metronidazole was undetectable or present at low concentrations.