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OUTBREAK OF SALMONELLA AGONA INFECTIONAFTER UPPER INTESTINAL FIBREOPTIC

ENDOSCOPY

SIR,-Your editorial on fibreoptic infections (Oct. 11) was timelysince there is increasing awareness of the need for thoroughdisinfection of fibre-endoscopic instruments. To add to earlierreports of outbreaks of salmonella infections, we describe here aseries of five patients with endoscopy-mediated salmonella infec-tion.Case l.-A 73-year-old man was admitted on Dec. 28, 1979, for

upper abdominal complaints. Endoscopy (Jan. 5) revealed a largebenign stomach ulcer and biopsies were done. Fever developed onJan. 6, with watery diarrhoea one day later. A salmonella of group Bwas cultured from the faeces; further typing (Rijks Instituut

Volksgezondheid, Bilthoven) revealed the strain to be Salmonellaagona. The patient recovered in a few days without antibiotics.Case 2.-A 76-year-old man with progressive weight loss under-

went a gastroscopy on Jan. 3, 1980. A large stomach ulcer wasfound. Diarrhoea and fever (39°C) developed on Jan. 5. Faecescultures were positive for a salmonella of group B, later identified asS. agona. Ampicillin and gentamicin were given, and he recoveredslowly.Case 3.-A man of 63 who had had a stomach resection for a

duodenal ulcer was admitted with hypochromic anaemia. Atgastroscopy on Jan. 25, 1980, a peptic ulcer of the jejunum wasfound. The following day he had a high temperature (39’ 3°C) withchills, nausea, and diarrhoea. A salmonella of group B was culturedfrom both blood and faeces. Serotyping confirmed S. agona. Am-picillin was given for 1 week (4 x 500 mg i.v.), which led to rapid im-provement.Case 4.-A 50-year-old male underwent, on Jan. 27, 1980, a

gastroscopy for a bleeding stomach ulcer. He was treated conser-vatively. The following day he had chills and fever up to 39°C, withwatery diarrhoea. Treatment was started with ampicillin (4 x I g)and gentamicin (3 x 80 mg). On Jan. 29 the diarrhoea was still pro-fuse. Bleeding recurred, requiring surgery. Prostoperatively he im-proved rapidly. S. agona was cultured from his stools.Case 5.-A 20-year-old male was admitted on Jan. 25, 1980, with

melaena and acute upper abdominal pain. At gastroscopy nodefinite ulcer could be found but afterwards shoulder paindeveloped and signs of guarding. He was operated on the same even-ing and a gastric ulcer was found. Postoperatively he did well. ByJan. 29 he had increasing diarrhoea, without fever. From the stoolsS. agona was isolated. He recovered in a few days without an-tibiotics.

Repeated isolation of this uncommon Salmonella serotype wassuspicious and inquiries revealed that all these endoscopies hadbeen done with the same instrument, culture of which yielded S.agona.In our hospital fibre-endoscopes were, at the time of the

salmonella outbreak, cleaned after use by careful washing followedby suction of cetrimonium bromide 1% through the fibre-

endoscopes which were then flushed with sterile water and dried.Water bottles and connection tubes were gas-sterilised daily. Fromthe gastroscope (Olympus GIF-K), however, S. agona could beisolated from the air-water channel, even after repeated flushingwith cetrimonium bromide. The failure of cetrimonium bromide to

produce adequate disinfection has been reported by others. 7,8

1. Chmel H, Armstrong D. Salmonella oslo: a focal outbreak in a hospital. Am J Med1976; 60: 203-08.

2. Tuffnell PG. Salmonella infections transmitted by a gastroscope. Can J Publ Health1976; 67: 141.

3. Dean AG. Transmission of Salmonella typhi by fibreoptic endoscopy. Lancet 1977; ii:134

4. Beeacham JH, Cohen ML, Parkin WE Salmonella typhimurium transmission byfibreoptic upper gastrointestinal endoscopy. JAMA 1979; 241: 1013-15.

5. Anon. Salmonella gastroenteritis acquired from gastroduodenoscopy. Morbid MortalWeekly Rep 1977; 26: 266.

6. Anon. Salmonella infection associated with gastroscopy. Communicable Dis Rep (UKPHLS) 1980; no 16 (April 25). Unpublished.

7. Carr-Locke DL, Clayton P. Disinfection of upper gastrointestinal fibreoptic endoscopyequipment: an evaluation of a cetrimide chlorhexidine solution and glutaraldehyde.Gut 1978; 19: 916-22.

8. Noy MF, Harrison L, Homes GKT, Cockel R. The significance of bacterial con-tamination of fibreoptic endoscopes. J Hosp Infect 1980; 1: 53.

Disinfection with alkaline glutaraldehyde 2% eliminated thesalmonella.

Although glutaraldehyde 2% is still considered the disinfectingsolution of choice, other agents such as ’Tegodor’ 1% (Th.Goldschmidt A. G., Essen) may be preferred because of the absenceof unpleasant toxic vapours. Tegodor contains formaldehyde,glutaraldehyde, and alkyldimethylbenzylammonium chloride (75,50, and 60 g/l, respectively).Careful disinfection of fibre-endoscopes before and after each en-

doscopy session with tegodor 1% has subsequently preventedbacteriological contamination. We would stress, however, that theirrigation-time of the air-water channel is critical. Disinfection ofthis channel after heavy experimental contamination with gram-negative bacteria (Pseudomonas cepacia) was, in our hands, not possi-ble with a flushing-time shorter than 15-20 min, either with

glutaraldehyde 2% or with tegodor 1%. Further trials of disinfec-tion procedures are in progress.

Department of Clinical Bacteriologyand Hospital Hygiene,

and Department of Gastroenterology,Free University Hospital,1007 MB Amsterdam, Netherlands

K. H. SCHLIESSLERB. ROZENDAALC. TAAL

S. G. M. MEAWISSEN

PROBLEMS WITH VITAMIN B12 ASSAYS

SIR,-We agree with Dr England and Dr Linnell (Nov. 15, p.1072) that one can encounter patients with normal serum totalcobalamin levels who are "functionally" cobalamin deficient. Someof these patients have normal haemoglobin levels but still manifestneurological and haematological features of megaloblastosis.Methylmalonic acid (MMA) is present in increased quantity in

the urine of patients who are deficient in 5-deoxyadenosylcobalamin 1 but not in patients with folate deficiency. In our depart-ment we can detect patients with low functional cobalamin bymeasuring the 24 h urinary excretion of MMA after a D,L-valineoral loading dose. The method used is a modification of that of Gut-teridge and Wright,2 using the extraction procedure of Stott el awl. 3It is done in a routine laboratory, requires no special apparatus, andthe results are generally available within one working day.To date we have investigated 30 patients, 15 of whom were MMA

negative and subsequently proved to be folate deficient. The totalcobalamin estimates (isotope dilution technique) for the 15 whowere positive for MMA excretion were as follows:

Thus 8 out of 15 patients had total cobalamins in the normal orlow normal range. All 15 patients responded to therapeutic doses ofhydroxocobalamin with brisk reticulocytosis, a drop in mean cor-puscular volume, a rise in Hb (if anaemic), and general symptomaticimprovement.We suggest that measurement of urinary MMA excretion in such

patients helps to make a diagnosis where serum cobalamin levels ap-pear to be at variance with the haematological assessment. Further-more the results may be available long before the serum cobalaminlevels.

Department of Pathology,Scarborough Hospital,Scarborough

I. C. BALFOURD. W. LANE

1. Hoffbrand AV. In: Hoffbrand AV, Lewis SM, eds. Tutorials in postgraduate medicine.vol 2: London: William Heinemann Medical Books, 1972: 69.

2. Gutteridge JMC, Wright EB. A simple and rapid thin-layer chromatographic tech-nique for the detection of methyl malonic acid in urine. Clin Chim Acta 1970; 27:289-91.

3. Stott AW, Lindsay Smith JR, Hanson P, Robinson R. A simple chromatographic pro-cedure for the concurrent estimation or urinary 4-hydroxy-3-methoxymandelic acid(HMMA) and homovanillic acid (HVA) using a scanning technique. Clin Chim Acta1975; 63: 7-12