Peritonitis in continuous ambulatory peritoneal dialysis.

The main complication of continuous ambulatory peritoneal dialysis (CAPD) is peritonitis. This paper describes our experience in the diagnosis and management of this complication in 66 patients during the three years to October 1982. The overall incidence of peritonitis was one episode every 6.75 patient months. Staphylococcus albus and Staphylococcus aureus together accounted for 46 per cent of the episodes, and 24 per cent were culture negative. Catheter exit site infections due to Staphylococcus aureus were common and they may have predisposed to peritonitis with gram -ve organisms as well as to staphylococcal peritonitis. Antimicrobial therapy was effective in 60 per cent of peritonitis episodes. The culture negative episodes usually responded to treatment while those due to fungi, though uncommon, did not. Twenty-nine per cent of these CAPD patients were transferred to haemodialysis because of peritonitis which failed to respond to treatment or which recurred repeatedly.

Short-term parenteral antibiotics used as a supplement to SDD regimens.

This discussion has presented detailed data relating to the use of systemic agents (in particular, cefotaxime) as a supplement to selective decontamination of the digestive tract (SDD) during the first few days of an intensive care unit admission. It suggests that this practice is rational and that it is employed for two distinct reasons--treatment of infection already present or developing on admission, and prophylaxis of infection acquired on the unit during the early days of admission. It is also suggested that this use of a systemic agent is an important factor in the striking reduction in unit acquired infection ascribed to SDD regimens.

Acute otitis externa in divers working in the North Sea: a microbiological survey of seven saturation dives.

Saturation diving is an important and widely used technique in the Offshore Oil Industry. During 1974-5 two saturation dives in the North Sea were terminated because of outbreaks of incapacitating otitis externa, and others were disrupted. Pseudomonas aeruginosa was consistently isolated from the ears of affected divers. Because complex work schedules were threatened seven subsequent dives were subjected to microbiological monitoring and control. Colonization of ear canal with P. aeruginosa or with other gram-negative bacilli occurred in 39 (67%) of the 58 divers studied, usually within 7 days of starting the dive. Data obtained by serotyping this isolations of P. aeruginosa suggested that a single infected diver may be the source of organisms which rapidly spread to his colleagues and throughout the living chambers, that the living chambers may constitute a reservoir of infection during and between dives, and that certain serotypes of P. aeruginosa are more likely than others to colonize the ear canal in the conditions of a saturation dive. The control measures used during the dives were only partially effective, but none of the divers suffered severe pain and all the dives were an operational success.

Effects of hyperbaric oxygen on the growth and properties of Pseudomonas aeruginosa.

Growth of Pseudomonas aeruginosa in 2 atmospheres absolute of 100% oxygen at 37 degrees C produced two types of abnormal colonies--stunted, rough colonies, termed dwarfs, and large, domed, mucoid colonies, termed giants. The occurrence of these variants depended upon the partial pressure of oxygen and the inoculum size. Subculture of dwarf or giant colonies produced a mixture of both colony types after incubation in hyperbaric oxygen, and colonies of normal appearance after incubation in air. Electron micrographs of ultrathin sections showed that cells from dwarf colonies had a more clearly defined envelope region than cells from normal colonies. Giant colony and normal colony-derived cells were of similar appearance. Whole cells from giant colonies contained more carbohydrate, readily extractable lipid, neutral lipid and free fatty acid than cells from normal colonies; the two cell types showed similar contents of 2-keto,3-deoxyoctonic acid and total phospholipid, but different proportions of individual phospholipids. Cells from dwarf, giant and normal (air-grown) colonies were incubated in air on nutrient agar containing either polymyxin, tetracycline or phenoxyethanol. Relative to cells from normal colonies, cells from dwarf colonies showed enhanced resistance to all three agents and cells from giant colonies showed enhanced resistance to polymyxin and tetracycline only. The resistance of cells from variant colonies was lost following a single subculture in air in the absence of antibacterial agents. It was concluded that the envelopes of cells from dwarf and giant colonies differed both from each other and from those of normal cells. These differences, and the formation of variant colonies, appeared to result from bacterial adaptation to hyperbaric oxygen rather than from mutation.

Cystic fibrosis--a review of 26 adolescent and adult patients.

Twenty-six patients, mean age 20.5 years (range 11-33 years) at last assessment or death, attended an adult cystic fibrosis clinic between 1975 and 1983. Twenty-one presented in infancy, and 5 later (3-17 years). Most morbidity was due to recurrent respiratory infection and 5 of the 7 deaths were from respiratory failure. Cor pulmonale occurred in 4 patients, pneumothorax in 3 and severe haemoptysis necessitating lobectomy in 2. Declining spirometric values and persistent isolation of Pseudomonas aeruginosa from sputum samples were associated with a poor prognosis. Minor gastrointestinal symptoms were common (19 patients). Four patients developed intestinal obstruction. Six patients had abnormal liver function tests and one patient died from hepatic cirrhosis. Diabetes was diagnosed in 3 patients and 9 patients experienced joint pains. The prognosis and quality of life for patients with cystic fibrosis appear to be improving, and all but 2 of the patients attending the clinic are at school, university or are employed.

Investigation of the immune status of mice during and following selective decontamination of the digestive tract.

Selective decontamination of the digestive tract (SDD) employs oral antibiotics to eliminate aerobic Gram-negative bacilli while retaining the anaerobic flora. A combination of SDD and parenteral cefotaxime has recently been reported to strikingly reduce the incidence of infection in patients treated in an intensive therapy unit. The present study describes the effects of SDD and of cefotaxime on the immune response of mice to protein antigens. The in vivo cellular response to ovalbumin and sheep red blood cells was unchanged. However, SDD appeared to decrease the in vitro mitogenic response of spleen cells to phytohaemagglutinin, and cefotaxime similarly affected the response to Concanavalin A. The antibody response to sheep red blood cells was increased in the period after discontinuation of SDD. The antibody response was otherwise not affected. These results indicate that SDD is unlikely to have adverse effects on the immune response to protein antigens.

Effect of hyperbaric oxyhelium gas on response of bacteria to antimicrobial agents in vitro.

Modern diving techniques can require the treatment of infection in an atmosphere of pressurized oxyhelium gas. The antibiotic susceptibility of 16 species and strains (eight genera) of gram-negative bacilli and 3 species and strains (two genera) of gram-positive cocci to each of 21 antimicrobial agents was assessed in air at atmospheric pressure and in oxyhelium gas at an absolute pressure of 7 bar (ca. 709 kPa). A disk diffusion technique was employed, and significantly different results were obtained in the two atmospheres. The effect of oxyhelium on diameters of growth inhibition varied significantly with the bacterium and with the antibiotic and was particularly marked with certain bacterium-antibiotic combinations. The gram-negative bacilli generally gave reduced zone diameters in oxyhelium, whereas the gram-positive cocci showed a mixture of effects.

Specific secretion of polypeptides from cells infected with myxoma virus.

The polypeptides secreted from cells infected with myxoma virus have been studied. Three virus-induced polypeptides were detected. One major and one minor polypeptide were synthesized and secreted in the absence of virus DNA synthesis; one minor polypeptide was not detected in the medium under such conditions. All these polypeptides were glycosylated and one was sulphated. Two precipitin lines were seen in Ouchterlony tests examining medium from infected rabbit cells and using serum from rabbits convalescent from myxoma virus infections. These antigens were unrelated to the virus-specific antigens released from cells infected with vaccinia virus. No major differences were detected in comparisons between the polypeptides secreted from cells infected with virulent and relatively avirulent strains of myxoma virus.

The effect of selective decontamination of the digestive tract with the addition of systemic cefotaxime on the aerobic faecal flora of mice.

The administration per-orally to mice of the non-absorbable antibiotics polymyxin E, tobramycin and amphotericin B resulted in the elimination of detectable aerobic gram-negative rods from the faecal flora without affecting the total viable aerobic count. The addition of parental cefotaxime to the regime caused a fall in the number of aerobic lactobacilli and an increase in the number of enterococci. The rise was associated with the translocation of viable enterococci to the mesenteric lymph nodes and the spleen. The changes induced by cefotaxime were reversed when the antibiotic was withdrawn. Following withdrawal of all antibiotics the total aerobic faecal flora increased to above normal levels, but there was no associated diarrhoea. Attempts to implant exogenous enterobacteria into the digestive tract resulted in only low level colonization both in treated mice and in control mice. These results may have implications for the use of this antibiotic regime for selective decontamination of the digestive tract in humans, particularly those who are immunocompromised.

Triple regimen of selective decontamination of the digestive tract, systemic cefotaxime, and microbiological surveillance for prevention of acquired infection in intensive care.

All 324 patients admitted over sixteen months to a general intensive therapy unit (ITU) were prospectively studied to assess the effect of a novel prophylactic antibiotic regimen on the incidence of acquired infection. Consecutive control (161 patients) and test (163 patients) groups were analyzed. In the control group, antibiotic administration was determined by clinical and microbiological evidence of infection. In the test group, treatment consisted of a triple regimen of selective decontamination of the digestive tract (polymyxin E, tobramycin, and amphotericin B) administered throughout the ITU stay, systemic cefotaxime administered for the initial four days, and regular microbiological screening of multiple sites. The test group showed a striking and consistent reduction in colonisation of the digestive tract with aerobic gram-negative bacilli, and there was a substantial reduction in the incidence of acquired infection (24% to 10%). Mortality in certain categories of patients was also reduced. There is now a considerable body of evidence to justify the more widespread use of this selective parenteral and enteral anti-sepsis regimen (SPEAR) in general intensive care practice.

The reduction of radiation mucositis by selective decontamination antibiotic pastilles: a placebo-controlled double-blind trial.

The aim of this study was to see if antibiotic pastilles could reduce radiation mucositis, pain, dysphagia and weight loss in patients undergoing radical radiotherapy for head and neck cancer. A total of 275 patients with T1-T4 tumours entered the study; 136 were allocated to suck four times daily a pastille containing amphotericin, polymyxin and tobramycin. The remaining 139 patients received an identical placebo. In all, 54 patients were unevaluable (24 active, 30 placebo). Bacteriological monitoring was carried out before and twice weekly during treatment. Both arms of the study were well balanced for T and N stage, age, sex and radiation dose (60 Gy). There was a slight imbalance in the site of disease which had no substantive effect on the results. The primary study end point was the percentage of patients who developed intermediate or thick pseudomembranes. No statistically significant difference was found in this end point, with 36% of patients in the active arm developing this type of membrane compared with 48% in the placebo arm (P = 0.118). The estimated odds ratio (placebo/active) of developing an intermediate or thick pseudomembrane was 1.59 (95% CI 0.89-2.82). However a more sensitive test comparing the worst recorded mucositis grade between the two arms was statistically significant (P = 0.009). This indicated that the active pastilles had a beneficial effect, but the magnitude was probably smaller than the trial was designed to detect. There was a reduction in mucositis distribution (P = 0.002), mucositis area (P = 0.028), dysphagia (P = 0.006) and weight loss (P = 0.009) in the active arm. There was a clear tendency for patients with positive cultures for aerobic Gram-negative bacteria (AGNB) (P = 0.003) and yeasts (P = 0.026) during treatment to have more severe mucositis. The active pastilles reduced the percentage of patients with yeast cultures (P = 0.003) but had less effect on AGNB. The benefit derived from the pastilles should materially increase patient tolerance to radical radiotherapy for head and neck cancer.