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M S Dryden

Publications and source records attributed to M S Dryden.

At least 19 recordsLinked to original sources
PubMed1994

Asymptomatic foodhandlers as the source of nosocomial salmonellosis.

A nosocomial outbreak of salmonellosis affected 22 patients and seven staff on 14 wards in two hospitals with shared catering facilities. The outbreak was characterized by a low level intermittent infection with Salmonella enteritidis phage type 4 over a 19-day period. The epidemiology did not suggest a common source for the outbreak and there was little evidence for person-to-person spread. Extensive food and environmental sampling failed to yield salmonella. Control measures within the kitchens and on wards early in the outbreak had no effect on the rate of infection. Faecal screening of asymptomatic people demonstrated a high carriage rate among catering staff (12.3%), compared with ward staff (2.2%) or patients (0.8%). A case-control study failed to reveal any association between illness and particular meals, food types, wards, medical attendants, medical procedures, or medication. However there was an association between illness and eating meals prepared by one carrier (P = 0.02). Transmission was believed to be via intermittent contamination of occasional meals. No further cases occurred after the exclusion of infected food handlers. The identifiable costs of the outbreak amounted to approximately pounds 33,000. These results indicate that asymptomatic food handlers may be the source of nosocomial salmonella outbreaks, and that efforts should be made to identify carriers and treat them.

Carrier State↗
PubMed1994

RAPD typing of clinical isolates of Staphylococcus haemolyticus.

The randomly amplified polymorphic DNA (RAPD) assay was used to generate DNA fingerprints from clinical isolates of Staphylococcus haemolyticus isolated from patients treated with continuous ambulatory peritoneal dialysis and previously subjected to a combination of typing methods. The RAPD profiles generated with one of six randomly designed 10-mer primers allowed visual discrimination of strains. Good correlation with the original typing scheme was achieved but RAPD typing allowed discrimination of strains previously indistinguishable.

Bacterial Typing Techniques↗
PubMed1994

Detection of Chlamydia trachomatis in general practice urine samples.

BACKGROUND: Chlamydia trachomatis is frequently overlooked as a cause of dysuria and urinary frequency in general practice patients. AIM: This study set out to determine the impact of performing chlamydial antigen detection on sterile pyuria samples from patients aged 16-65 years and which were submitted to a hospital microbiology laboratory by general practitioners in the Winchester health district for routine microbiological investigations. METHOD: Chlamydial antigen detection was performed by enzyme immunoassay and direct immunofluorescence. The cost of performing the test was estimated. In the first year of the study (1991) questionnaires were sent to general practitioners whose patients had a positive test result. RESULTS: A total of 1025 samples of sterile pyuria were received at the laboratory between January 1991 and March 1993. Chlamydial antigen was detected in 54 samples (5%); 22 men and 32 women aged between 16 and 57 years (mean 25 years). The detection rate was highest in the 16-20 years age group (22% of men had a positive sample and 7% of women). Completed questionnaires from 27 general practitioners revealed that 59% of their patients were referred to the genitourinary clinic for treatment and contact tracing. The others were treated by the general practitioner. The cost of the screening programme per cure in this population was estimated to be 246 pounds. CONCLUSION: C trachomatis is a significant pathogen which may go unrecognized and untreated. The cost, medically and financially, of screening for this pathogen and treating infected patients and contacts is likely to be less than ignoring it, particularly if screening is confined to the 16-30 years age group. General practitioners should consider the diagnosis of chlamydial infection in young adult patients with sterile pyuria, and microbiology laboratories should screen sterile pyuria samples for chlamydial antigen.

Adolescent↗
PubMed1992

Controlled trial of a Y-set dialysis delivery system to prevent peritonitis in patients receiving continuous ambulatory peritoneal dialysis.

Peritonitis rates were compared in patients receiving continuous ambulatory peritoneal dialysis (CAPD) via either a Y-set dialysate delivery system or a standard system. Forty patients in each arm of the trial were matched for age (range 20-67 years, mean 49 years), and remained in the study for similar periods (range 3-36 months, mean 14.1 months). The observation time was 564 patient-months for each arm of the trial. There were 22 episodes of peritonitis in nine out of 40 patients using the Y-set and 57 episodes in 21 out of 40 patients using the standard system (P = 0.005 Wilcoxon signed rank test for episodes, P = 0.02 McNemar's chi 2 test for patients). Peritonitis rates were one episode per 25 patient-months in the Y-set group, and one episode per 9.7 patient-months in the standard group. In the Y-set group there were significantly fewer episodes caused by coagulase-negative staphylococci and Acinetobacter spp. There was no difference in the rate of episodes caused by Staphylococcus aureus, streptococci, enterococci, corynebacteria, enterobacteria or pseudomonads. There was no difference in the incidence of catheter exit wound infections. The Y-set dialysis delivery system is effective in reducing peritonitis rates in CAPD patients caused by organisms derived from the commensal skin flora, principally coagulase-negative staphylococci, but does not reduce peritonitis caused by other organisms.

Acinetobacter↗
PubMed1992

Evaluation of methods for typing coagulase-negative staphylococci.

One hundred and forty-two coagulase-negative staphylococci (CNS) isolated from dialysate effluent or skin of patients receiving continuous ambulatory peritoneal dialysis (CAPD) were typed by extended antibiogram (16 antibiotics) and biotype (26 reactions). These isolates were then typed by supplementary methods to determine the most suitable typing method for an epidemiological study of antibiotic resistance. These included phage typing, reverse phage typing, plasmid typing, whole-cell protein typing by SDS-PAGE with analysis by densitometry, and immunoblotting. The percentage of isolates typed successfully by the supplementary methods were: phage typing 20%, reverse phage typing 0%, plasmid typing 66%, SDS-PAGE 100%, immunoblotting 100%. The discrimination of each method was: phage typing 20%, plasmid typing 37%, SDS-PAGE 69%, immunoblotting 57%. Reproducibility was 88% for phage typing and 97% for plasmid typing. The reproducibility of the whole-cell protein typing was 83% if the same extracts were used but only 43% when separate protein extracts were analysed on separate occasions. However, strain relatedness was highly reproducible. The determination of an antibiogram-biotype profile was not a sufficiently accurate typing method for an epidemiological study of antibiotic resistance. Whole-cell protein typing by SDS-PAGE or immunoblotting was technically demanding but was the most effective of the supplementary methods for detecting erroneous discrimination and false matching produced by antibiogram-biotype combinations.

Bacterial Proteins↗
PubMed1992

The epidemiology of ciprofloxacin resistance in coagulase-negative staphylococci in CAPD patients.

Ciprofloxacin was used as empirical therapy for peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD) for 26 months, providing an opportunity to study the epidemiology of ciprofloxacin resistance amongst coagulase-negative staphylococci (CNS). Swabs were collected from the CAPD patients, staff, and clinic environment before, during and after the time this antibiotic was prescribed. Clinical isolates were also studied, and records kept of patient hospital attendance. Ciprofloxacin-resistant staphylococci were typed by antibiogram, biotype, plasmid profile, SDS-PAGE, and immunoblotting. No resistant strains were detected before the use of ciprofloxacin. During its use 30% of patients became skin carriers, and resistant strains caused 8% of peritonitis episodes in 7% of patients (38% of carriers). Resistant strains were isolated from the environment, but never from attending members of staff. A total of 208 resistant isolates with MIC's between 8 and 128 mg/l was collected and identified as Staphylococcus epidermidis or S. haemolyticus. Sixteen strain types were distinguished. There was epidemiological evidence for selection of resistant strains derived from the host commensal flora and also for cross-colonization, and cross-infection. Carriage of resistant strains fell to 15% of patients, 6 months after the use of ciprofloxacin had ceased.

Air Microbiology↗
PubMed1991

Infective complications associated with the use of the Quinton 'Permcath' for long-term central vascular access in haemodialysis.

The major complication of central venous catheterization for immediate access for haemodialysis is infection. The Quinton Permcath is a tunnelled, double lumen, flexible silastic catheter with a Dacron cuff, and is claimed to be associated with a low rate of infection. In a two-year study we have monitored all complications including catheter-associated infection related to this device in haemodialysis patients while following a simple aseptic programme for the care of the catheter exit wound. Thirty four Permcaths were inserted in 30 patients for a mean duration of 6.2 months (SD +/- 5.7; range 2 days to 23 months). Catheter use amounted to a total of 197 months. Of twenty-seven catheter wound infections, 6 (22%) were caused by Staphylococcus aureus, and 15 (56%) by coagulase-negative staphylococci or corynebacteria. These occurred in 19 patients, giving an exit site infection rate of one episode per 7.4 catheter months. Catheter-associated septicaemia occurred in three patients (two S. aureus, one S. epidermidis), at a rate of one episode per 66 months. It was possible to correlate three episodes of infection with breakdown in aseptic care. This study confirms the low rate of infection associated with the use of the Permcath, and we conclude that the design of the device and aseptic care of the catheter and its wound contribute to this.

Adult↗
PubMed1991

Low dose intraperitoneal ciprofloxacin for the treatment of peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD).

Ciprofloxacin at a dose of 25 mg/L of dialysate was administered intraperitoneally for five days as a single agent for the empirical treatment of CAPD peritonitis. One hundred and seventeen consecutive episodes of peritonitis occurred in 65 patients during the study period, and 100 episodes were entered in the study. This therapy was successful in 79% of episodes. Resistant organisms (MIC greater than 4 mg/L) all of them coagulase-negative staphylococci, were isolated in nine (7.8%) of the 117 episodes. Mean ciprofloxacin concentrations in dialysate and serum on the last day of treatment were 6.1 mg/L (range 0.3-15.7) and 0.3 mg/L (range 0-0.9) respectively. No adverse effects were reported.

Adolescent↗
PubMed1991

Active intervention dramatically reduces CAPD-associated infection.

In 1987 a preventive programme was initiated to address the problem of high hospital and community-acquired CAPD infection. It concentrated on reducing Staphylococcus aureus carriage, improving aseptic operative technique, intensive training for nursing staff and patients in stringent aseptic care of the exit site, and avoidance of contact of the exit site with unsterile water. This programme was associated with an overall 10-fold reduction in exit site infection, a 2-fold reduction in peritonitis, and a 4.5-fold reduction in catheter loss from infection. These reductions have been sustained. Preventing infection in CAPD patients requires persistence and commitment but improves the patient's quality of life and reduces the cost of treatment.

Asepsis↗
PubMed1988

The microbial causes of diarrhoea in patients infected with the human immunodeficiency virus.

Diarrhoea is common in patients infected with the human immunodeficiency virus (HIV). We sought the cause of diarrhoea in all HIV antibody-positive patients with diarrhoea who presented at St Stephen's Hospital, London over a period of 15 months. Altogether, 441 specimens from 179 patients were examined. Infective causes were found in 86 (48%) patients. Protozoa were the most common infecting organisms (30% patients). Of these, Cryptosporidium sp. was the most frequent (9.5% patients), followed by Entamoeba histolytica and Giarda lamblia. 'Non-pathogenic' protozoa (NPP) were also common (15% patients), often in the absence of generally recognised pathogens. A case controlled study failed to show a significant difference in the rate of isolation of NPP in HIV antibody-positive patients with diarrhoea compared with HIV antibody-positive patients without diarrhoea. Bacterial causes of diarrhoea were found as follows: Salmonella spp., Campylobacter spp. and Shigella sonnei; Mycobacterium avium-intracellulare (MAI) was isolated from the faeces of eight (4.5%) patients. Isolation of MAI from faeces was associated with disseminated MAI infection. This study has shown that two commonly isolated pathogens, namely Cryptosporidium sp. and MAI, can be identified quickly and reliably by the same modified Ziehl-Neelson staining of concentrated faeces.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Disseminated Mycobacterium avium-intracellulare infection and red cell hypoplasia in patients with the acquired immune deficiency syndrome.

During a period of 14 months in 1985 and 1986, infection with Mycobacterium avium-intracellulare (MAI) complex was diagnosed in 10 of 76 patients with Human Immunodeficiency Virus (HIV)-associated infection. In eight of the 10 patients, the infection was disseminated. All eight patients were anaemic. A bone marrow aspirate and/or trephine biopsy performed in six of them revealed evidence of red cell hypoplasia. MAI was cultured from all six samples of bone marrow. The strains of MAI isolated were resistant to conventional antituberculous drugs but were susceptible in vitro to ansamycin, ethionamide and cycloserine. None of the eight patients responded clinically to antituberculous therapy. The eight anaemic patients had pronounced constitutional symptoms. We suggest that severe anaemia and constitutional symptoms in patients with HIV-associated disease should prompt a search for evidence of disseminated MAI infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Cryptosporidial diarrhoea in AIDS and its treatment.

Of 234 patients with AIDS diagnosed at St. Stephen's Hospital between January 1981 and June 1987, 26 (11%) were found to have cryptosporidiosis. Stool examination was positive in all patients, but an average of three specimens (range 1-6) were required before a positive diagnosis was made. Other methods of diagnosis included jejunal and rectal biopsy and aspiration of the duodenal contents. Twenty three (89%) lived for six months from the time of diagnosis and 16 (60%) were alive at one year. Only five patients died as a direct result of cryptosporidial infection, while 10 other patients died from another complication of AIDS. Fifteen patients were enrolled in a prospective controlled study of erythromycin or spiramycin in the treatment of cryptosporidial diarrhoea. Most patients showed a significant response to antibiotic therapy but treatment was limited because of side effects. All patients responded to antidiarrhoeal agents, particularly long acting morphine sulphate. Three of our patients recently given zidovudine (AZT) have responded with a cessation of diarrhoea and cryptosporidia are no longer isolated from the stools.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Comparison of methods for isolating Mycobacterium avium-intracellulare from blood of patients with AIDS.

A variety of blood culture media were compared to determine the optimal method for the isolation of Mycobacterium avium-intracellulare (MAI) from the blood of patients with AIDS. Simulated laboratory blood cultures and clinical blood cultures were tested. Glucose broth, Bactec aerobic medium, Kirschner's medium, and Bactec Middlebrook medium supported the growth of MAI. The Isolator system, a lysis centrifugation method, facilitated the most rapid isolation of MAI (p = 0.001). The Bactec Middlebrook medium gave the most rapid detection rate (p = 0.001) as acid fast bacilli could be stained by the Ziehl-Neelson method before colonies were isolated in the Isolator system. The growth index readings did not reliably predict mycobacterial growth in the two radiometric media tested. Although several methods may be used to isolate MAI from blood, the most rapid and sensitive method is the Isolator system used in combination with the Bactec Middlebrook medium.

Acquired Immunodeficiency Syndrome↗