D.A. Leigh

The cost of infection in surgical patients: a case-control study

To determine the excess hospital cost attributable to hospital acquired infection in a UK hospital 67 surgical patients with hospital acquired infection (HAI) were matched with uninfected controls on the primary features of the first operative procedure and primary diagnosis, and on the secondary features of sex, age and surgical service. Costs were calculated from the hospitals unit costs for pathology, radiology and for the cost of one days extra stay. The mean cost of one day of antibiotic therapy was also measured. In infected patients there was a significant increase in the length of hospital stay of 8.2 days with a mean extra cost per patient of 1041 pounds (P < 0.001). Microbiology, haematology, chemical pathology and radiology requests were all significantly increased with a mean extra cost per infected patient of 10.4 pounds, 7.8 pounds, 96. pounds, and 3.3 pounds, respectively. Antibiotic therapy contributed significantly to the extra costs (44 pounds per infected patient). The mean extra cost per patient was highest in orthopaedic patients (2646 pounds) and least in gynaecology patients (404 pounds). For the infections with significantly increased cost, multiple infections carried the greatest (3362 pounds), and urinary tract infections the least (467 pounds) cost. Hospital length of stay was the greatest contributor to the cost and accounted for 95% of the extra cost in orthopaedics, 94% in gynaecology and 92% in general surgery and urology. Antibiotic therapy was the second most significant contributor to cost and, with the exception of urinary tract infection and infections in gynaecology, was at least five times more per patient than requests for microbiology, haematology, chemical pathology or radiology.

Design and execution

Summary A study to determine the prevalence of infection among patients in hospital in England and Wales was designed during 1979. The methods to be used were tested in a pilot study. After the hospitals to be involved had been selected and the personnel concerned trained, a survey involving 43 hospitals and 18,186 patients was completed in mid-1980. The methods that were employed are described, and where necessary simplifications or improvements are suggested. The level of comparability in the methods used and the results achieved by the teams from different hospitals is discussed.

An investigation into Clostridium perfringens enterotoxin-associated diarrhoea

An investigation was carried out to establish the incidence of diarrhoea associated with the presence of enterotoxigenic Clostridium perfringens. The results indicate a high risk group, namely elderly hospitalized patients, who should be investigated for this organism in a similar way to Clostridium difficile if symptoms occur. The significance of antibiotic association is suggested and cross-infection was shown to be a possibility. Detection of the enterotoxin was accompanied in all cases by the presence of high faecal counts of enterotoxigenic strains of C. perfringens.

An eight year study of postoperative wound infection in two district general hospitals.

Abstract Between 1971 and 1978 the incidence of wound infection in 29,941 patients undergoing major or intermediate categories of surgical operations was studied at two district general hospitals. The overall incidence of infection was 5·4 per cent and there was a gradual fall over the period of study. The infection rate in clean operations was 2·9 per cent, in clean-contaminated operations 8·6 per cent and in contaminated operations 12·9 per cent. Thirty-nine per cent of wounds were infected with Staphylococcus aureus and the incidence of anaerobic wound infections was related to improvements in laboratory methods and chemoprophylaxis. Infection surveillance studies and the distribution of the findings to all members of the theatre and ward teams are essential factors in the control of postoperative wound infection.

Post-operative urinary tract infection and wound infection in women undergoing Caesarean section: a comparison of two study periods in 1985 and 1987

In 1985 and 1987 women undergoing Caesarean section were studied for the development of post-catheterization bacteriuria, urinary tract infection and wound infection. In 1985, 34% developed bacteriuria compared to 25% in 1987. Post-catheterization bacteriuria within two days was reduced by improved catheterization techniques. Late urinary tract infection after 5 days occurred in 2% of women in 1985 and 6% in 1987. The commonest bacteria were Escherichia coli and enterococci. Post-catheterization bacteriuria was only confirmed in a second urine specimen in 53%. The incidence of wound infection was 20% in 1985 and 15.8% in 1987 but bacterial pathogens were only isolated from 12.5% and 5.1% respectively. Staphylococcus aureus was isolated in 60% of infected women. Antimicrobial usage was high in this group of women at 41% in 1985 and 27% in 1987. A significant reduction of usage from 37% to 16% was seen in bacteriologically confirmed infections where the laboratory reports were only issued after examination of a second specimen. However most symptomatic women received treatment. The incidence of post-operative infective complications is high in women having Caesarean section. Careful urethral catheterization techniques are necessary to prevent bacteriuria.

Urinary Tract Infection

Summary Infection of the urinary tract was the most prevalent of the hospital acquired infections recorded in the survey, and the second most prevalent among all that were detected. It was diagnosed in 809 cases, representing 22 per cent of all infections, or 30·3 per cent of cases of hospital acquired and 14·5 per cent of community acquired infections, respectively. Eight point six per cent of patients were found to be catheterized at the time of the survey, and of these, 21·2 per cent were infected. Only 2·9 per cent of the non-catheterized population was infected.

An 11-month incidence study of infections in wards of a district general hospital

Between March 1988 and January 1989, an incidence study of infections in patients occupying 122 beds in a district general hospital was undertaken. Nursing notes, medical notes, temperature charts, drug prescription charts and laboratory information were reviewed three times a week to determine if patients had infection which met strict case definitions. In addition, the surveyor consulted with ward nursing and medical staff for clarification of symptoms and signs indicative of infection. During the study, 668 infections were identified amongst 3326 patients. Three hundred and thirty-eight (51%) were community-acquired infections (CAI) and 330 hospital-acquired infections (HAI). Excluding 24 HAI acquired in other hospitals, the incidence rates were 9.2 HAI per 100 discharges, and 1.1 HAI per 100 patient days. The common types of CAI were pneumonia, abdominal infection and urinary tract infection. The main types of HAI were urinary tract infection, surgical wound infection and pneumonia. The microorganisms most frequently associated with CAI and HAI were Gram-negative bacilli.

The general distribution of infection

Summary A study to determine the prevalence of infection among patients in hospital in England and Wales was conducted in mid-1980. Of 18,163 patients studied, 19·1 per cent were infected, about half of the infections being acquired before entry into hospital. Overall, respiratory infection was the most prevalent, though the larger part of this was brought into hospital from the community. Among hospital acquired infections the most common was that of the urinary tract (2·8 per cent of all patients). This was followed in frequency by infection of wounds (1·7 per cent) and the lower respiratory tract (1·5 per cent). Nearly all the infections recorded were of the sporadic or endemic variety. An unknown proportion of these infections is preventable.

Respiratory tract infections

Summary Respiratory tract infections were the most prevalent of those found in the survey, being diagnosed in 30·2 per cent of the 3473 infected patients. They were divided into upper respiratory infections (in 4·8 per cent of infected patients, a rate of 0·9 per cent overall) and lower respiratory infections (24·5 and 4·7 per cent). Most of the latter were acquired in the community (16·4 and 3·1 per cent). The distribution of these infections by sex, age and speciality is presented, and the organisms found in association with them are recorded.

Infections at other sites

Summary Among the infections recorded in the survey, 38·8 per cent were of sites other than the respiratory or urinary tracts, or of wounds. Just under half of these ‘other infections’ were of the skin. The remainder were a collection of various individually rather infrequent conditions, the maximum contribution of any one to the total of all infections being 4·0 per cent.