P.D. Meers

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.

Bacteraemia in surgical patients with intravenous devices: A European multicentre incidence study

A survey of the incidence of bacteraemia and the use of intravenous (IV) devices among 10,616 surgical patients was performed in 42 hospitals in eight countries. It was found that 63 per cent of the patients surveyed had an IV device inserted at some time during their hospital stay, with national variations between 40 and 99 per cent. The incidence of device-related thrombophlebitis was 10.3 per cent, with national variations between 7.8 and 28.4. Among the surgical patients not given IV therapy, 1.5/1000 had a bacteraemia, 0.5/1000 of them hospital-acquired. The corresponding figures for patients with a peripheral but no central IV device were 6.9 and 3.7, and for patients with a central venous catheter (CVC) 59.0 and 44.8, respectively. Even though there was a strong correlation between the incidence of bacteraemia and certain diagnoses there was also an independent correlation between it and CVCs or peripheral IV lines. No correlation was demonstrated between the number of catheter days per site for patients with a peripheral IV device, and hospital-acquired bacteraemia. This may be due to the low mean number of catheter days per site that was observed. There was a large and not easily explained national variation in the incidence of bacteraemia in patients with CVCs of between 16 and 108/1000.

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.

The impact of methicillin- and aminoglycoside-resistant Staphylococcus aureus on the pattern of hospital-acquired infection in an acute hospital

Infections due to methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) appeared in a new teaching hospital shortly after it opened. The effect this had on the pattern of hospital-acquired infections in the four years that followed is described. No control measures were applied and MARSA became endemic. New infections appeared at a rate of about four for each 1000 patients discharged. It established itself at different levels of incidence in various specialist units, patients under intensive care being most severely affected. MARSA was implicated in half of all hospital-acquired infections due to S. aureus but it was not more pathogenic than its more sensitive counterpart. It had little impact on the life of the hospital.

Microbiological aspects of the 1980 national prevalence survey of infections in hospitals

The records of the 1980 national prevalence survey of infection in hospitals were re-assessed from a microbiological point of view. Of 407 records of Escherichia coli, 71 per cent came from the urinary tract while the commonest source of Staphylococcus aureus was from skin infections. These yielded only 41 per cent of the 303 records. Proteus spp. were recorded 166 times, Pseudomonas spp. 115 times and Klebsiella spp. 101 times. These came mainly from the urinary tract but other sources were important. Streptococcus pneumoniae, Haemophilus influenzae, Mycobacterium tuberculosis and the viruses were associated with community infections while E. coli, Proteus spp., Pseudomonas spp., Klebsiella spp., Str. faecalis and non-aureus staphylococci were associated with hospital-acquired infections. The prevalence of bacteraemia was re-assessed.

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.

Partial characterization of an endemic strain of a methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) homogeneously resistant to β-lactam antibiotics

Selected strains of methicillin- and aminoglycoside-resistant Staphylococcus aureus (MARSA) were subjected to a preliminary examination. They were representative of a larger group collected in a routine clinical microbiology laboratory over a period of 2 years. MARSA was endemic in the associated hospital. The characteristics investigated were antimicrobial resistance, the production of beta-lactamase, free and bound coagulase, protein A, DNA-ase, urease, lipase and pigment. The MARSA strains were generally indistinguishable, other than in their antimicrobial resistances. The resistance to methicillin was completely homogeneous. Except with imipenem, growth extended to the edge of discs containing methicillin and the other beta-lactam antibiotics tested when the strains were cultured at 37 degrees C on media without added salt. Homogeneous resistance may confer an epidemiological advantage on strains of this phenotype.

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.