Journal of Hygiene最新文献

A 1-year prospective study of nosocomial bacteraemia was performed at Hvidovre Hospital with special reference to frequency, focus of infection and prognosis. All patients were examined clinically in order to confirm the bacteraemia. In total, 98 hospital-acquired bacteraemias were observed, giving an incidence rate of 0.28%. Bacteraemia due to Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis predominated. The overall mortality was 38%; 65% of the patients with S. aureus bacteraemia died, 25% due to the bacteraemia. The most common types of infection were urinary tract infections and intravenous catheter infections. Fifty-five of the bacteraemias were caused by foreign bodies, mostly urinary catheters and intravenous catheters, and in 14 cases the focus was unknown. The patient population was severely ill patients. We conclude that nosocomial bacteraemia occurs specially in severely ill patients often preceded by indwelling urinary or intravenous catheters. The patients seldom die due to the bacteraemia, but they die with concomitant bacteraemia.

A survey was undertaken of the occurrence, serotype, antimicrobial sensitivity and plasmid content of members of the tribe Proteeae in the environment of two calf-rearing units in the county of Avon in South West England. Examples of the following species were found: Proteus mirabilis, Prot. vulgaris, Prot. vulgaris Biogroup 2, Morganella morganii, Providencia stuartii, Prov. alcalifaciens and Prov. rettgeri. A wide range of serotypes was found, many having been previously reported from nosocomial isolates. A total of 15% of isolates carried plasmids; six pairs of isolates were identified which had identical serotypes but different patterns of plasmid carriage. The antimicrobial sensitivity of the isolates was generally similar to isolates of Proteeae from humans. Although no truly aminoglycoside-resistant isolates were found, some isolates of Prov. stuartii and Prov. rettgeri had MIC's higher than the other isolates to gentamicin and netilmicin, suggesting the presence of low levels of the enzyme AAC 2'. The study demonstrates that there is a considerable diversity of species and types of Proteeae associated with calves and their environment. It seems likely that a potential cause of colonization of the human gut by Proteeae is the consumption of meat.

The apparent reduction in the incidence of subsequent joint sepsis and of re-operation without evidence of infection during the course of a prospective study was an artifact of the analysis method.

An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of brucella-specific IgG, IgM and IgA in 173 patients with acute brucellosis, 22 patients with chronic brucellosis and in 281 controls consisting of 98 patients with other infectious etiologies, 20 patients with non-infectious diseases and 163 normal healthy adults. The ELISA results were compared with culture findings, the results of slide agglutination tests with Brucella melitensis (M), B. abortus (A) and Ross Bengal (RB) antigens, and of tube and microagglutination tests. Brucella cultures were positive in 53 and 5% of patients with acute and chronic brucellosis respectively. The slide agglutination tests with A, M, A plus M and RB antigens were positive in 42, 44, 51 and 98% of patients with acute brucellosis and in 23, 27, 27 and 64% of patients with chronic brucellosis. There was no significant difference in the results between the tube and microagglutination tests regardless of the type of antigen used. At a titre of greater than or equal to 80 or greater than or equal to 160 these tests were positive in 98% and 92% of patients with acute brucellosis and 60 and 40% of patients with chronic brucellosis. The brucella culture and agglutination tests were negative for all the controls. Brucella ELISA immunoglobulins (Ig) were detected in some individuals in the control groups but the majority of these had titres of less than or equal to 100 for IgG, IgM, and IgA. However, patients with brucellosis had significantly higher ELISA titres in all classes of Ig than controls but the sensitivity and specificity within each Ig class varied with the titre considered. At a titre of greater than or equal to 1600 the brucella IgG had a sensitivity and specificity of 98% for patients with acute or chronic brucellosis; this decreased with lower reciprocal titres. The brucella IgM titre of greater than or equal to 400 had a sensitivity of 98% and a specificity of 98% for patients with acute brucellosis. However, in patients with chronic brucellosis the brucella IgM was very low. The brucella IgA titre of greater than or equal to 200 showed a sensitivity of 98% and a specificity of 99% for patients with either acute or chronic brucellosis. This study indicates that brucella ELISA is a rapid, sensitive and specific assay, provides a profile of Ig classes in the diagnosis of acute and chronic brucellosis, is useful for mass screening and could be considered the method of choice for the serological diagnosis of brucellosis.

In Salmonella typhimurium phage type 204c isolated in Britain, gentamicin resistance is specified by plasmids of the I1 compatibility group which also confer resistance to apramycin. These plasmids have been subdivided into three types within the I1 group on the basis of their antibiotic resistance specificity, their ability to produce colicin Ib and their restriction enzyme digest fragmentation patterns. All three have been identified in strains from cattle, but as yet only two types have been found in strains from humans. It is suggested that the use of apramycin in animal husbandry is responsible for the appearance of gentamicin resistance in multiresistant strains of phage type 204c, a phage type already epidemic in bovine animals and with an increasing incidence in humans.

A four-component solid-phase capture enzyme immunoassay was set up to test for serum IgM antibody to respiratory syncytial (RS) virus and was compared with immunofluorescence assay (IFA). A total of 128 young children with acute respiratory infections were studied. Thirty-six were shown to be RS virus-positive by the detection of RS virus in nasopharyngeal secretions and 92 were RS virus-negative. A serum specimen was collected after admission to the hospital (days 0-4) and a further specimen was obtained during days 10-14. Out of 36 RS virus-positive patients, 28 (77.7%) were found to be positive for IgM by both capture-ELISA and IFA. Out of 92 RS virus-negative patients 5 (5.4%) were IgM-positive. Four false-positive results were obtained by IFA due to the presence of rheumatoid factor. The capture-ELISA was shown to be a reliable technique in detecting specific IgM antibody to RS virus.

The survival of Escherichia coli in an aerosol was studied at several temperatures and over a range of relative humidities using a Henderson apparatus. Death occurred in two phases, the first lasting approximately 1 min; in the second the number of viable microorganisms declined exponentially. E. coli was robust and remained viable for many hours. Death was most rapid at low humidities (less than 50% r.h.) at 15 and 30 degrees C, with half-lives of 14 and 3 min respectively. In humid conditions the half-lives were much longer, approximately 83 and 14 min respectively. Based on this work, preliminary recommendations for the climate of livestock buildings can now be given to control the airborne spread of E. coli.

A survey on the bacteriological quality of both drinking water and flavoured drinks from coin-operated vending machines is reported. Forty-four per cent of 25 drinking water samples examined contained coliforms and 84% had viable counts of greater than 1000 organisms ml at 30 degrees C. Thirty-one flavoured drinks were examined; 6% contained coliforms and 39% had total counts greater than 1000 organisms ml. It is suggested that the D.H.S.S. code of practice on coin-operated vending machines is not being followed. It is also suggested that drinking water alone should not be dispensed from such machines.

Amounts of Mycobacterium tuberculosis antibodies were determined in sera from patients with either active or inactive tuberculosis and in healthy subjects by an immunoenzymatic assay in which whole BCG cells attached covalently to polystyrene disks were used as antigen. Statistically significant differences (P less than 0.005) were found both between the active and inactive tuberculosis groups and between the active group and healthy controls. No significant differences were found between the inactive group and controls. Since this procedure is efficient (91%) and can be used in areas which lack laboratory equipment, it appears promising for individual serodiagnosis and for epidemiological surveys.