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M K Dasgupta

Publications and source records attributed to M K Dasgupta.

At least 19 recordsLinked to original sources
PubMed2000

A multicenter study of noncompliance with continuous ambulatory peritoneal dialysis exchanges in US and Canadian patients.

Recent evidence suggested that noncompliance (NC) with continuous ambulatory peritoneal dialysis (CAPD) exchanges may be more common in US than in Canadian dialysis centers. This issue was investigated using a questionnaire-based method in 656 CAPD patients at 14 centers in the United States and Canada. NC was defined as missing more than one exchange per week or more than two exchanges per month. Patients were ensured of the confidentiality of their individual results. Mean patient age was 56 +/- 16 years, 52% were women, and 39% had diabetes. The overall admitted rate of NC was 13%, with a rate of 18% in the United States and 7% in Canada (P < 0.001). NC was more common in younger patients (P < 0.0001), those without diabetes (P < 0.001), and employed patients (P < 0.05). It was also more common in black and Hispanic than in Asian and white patients (P < 0.001). NC was more common in patients prescribed more than four exchanges daily (P < 0.0001) but was not affected by dwell volume. On multiple regression analysis, the independent predictors of NC, in order of importance, were being prescribed more than four exchanges per day, black race, being employed, younger age, and not having diabetes. Being treated in a US unit did not quite achieve significance as a multivariate independent predictor. These findings suggest that NC is not uncommon in CAPD patients and is more frequent in US than in Canadian patients. However, country of residence is less powerful as a predictor of NC than a variety of other demographic and prescription factors.

Adult↗
PubMed1998

Rapid growth in the use of automated peritoneal dialysis (APD) in adult patients on peritoneal dialysis.

Inadequate dialysis dose is associated with poor patient-survival in peritoneal dialysis (PD). Most patients would require more than four exchanges a day after losing residual renal function. The use of automated peritoneal dialysis (APD) seems to be a practical way to provide extra dialysis for these patients. In our Dialysis Centre in Northern Alberta, we started to use APD for our adult patients only from 1993. When we evaluated our practice recently, we found that we are progressively increasing the use of APD (including cyclers and night exchange devices) from 3% to 21% for our total adult PD patients in the last 3 years. This increase in the use of APD is mostly to accommodate PD prescription changes and not changes in lifestyle. Increase in the use of APD was associated with decrease in the rate of our PD dropout to hemodialysis. We conclude that to maintain adequate dialysis, rapid growth of APD will become common in North American PD centers in the future and will reduce transfer to hemodialysis.

Adult↗
PubMed1997

The effects of macrolide and quinolone antibiotics in methicillin-resistant Staphylococcus aureus biofilm growth.

Recent studies demonstrate that 14-membered macrolides increase permeability and destruction of Pseudomonas biofilms. The effect of a macrolide antibiotic, erythromycin, on methicillin-resistant Staphylococcus aureus (MRSA) biofilm on Silastic catheter materials in comparison with two different quinolone antibiotics, sparfloxacin (SPFX) and a new quinolone, SYN 1193, was examined. Two different MRSA strains were grown in biofilm, using Mueller-Hinton broth with and without the addition of 10% pooled normal human serum (PNHS), in a modified Robbins device, at 37 degrees C for 24, 48, and 72 hours. Two different clinical MRSA strains were used and minimum bactericidal concentration (MBC) were determined at the time intervals mentioned. Three different dosages of each antibiotic were tested: 5.0, 20.0, and 50.0 micrograms/mL. In addition, a constant dosage of SPFX and SYN 1193, in combination with varying dosages of erythromycin, was tested under similar experimental conditions. SYN 1193 demonstrated the highest MBC in comparison to SPFX; addition of PNHS did not alter the effect of SYN 1193. However, erythromycin alone and in combination with SPFX and SYN 1193 had no effect on MBC. We conclude that (1) macrolide antibiotic erythromycin has poor MRSA biofilm permeability and killing in comparison to SPFX and SYN 1193, and (2) SYN 1193 had the highest MBC to MRSA biofilm.

Anti-Bacterial Agents↗
PubMed1996

Biofilm causes decreased production of interferon-gamma.

Interferon-gamma, a cytokine, is produced by lymphocytes when they are stimulated by cytokines from activated macrophages, and is essential for macrophage-mediated bactericidal operations. To investigate whether a strain of bacteria can activate macrophages and lymphocytes, the interferon-gamma levels may thus be measured. Current literature maintains that peritoneal dialysis patients with recurrent peritonitis have "unhealthy" macrophages and lymphocytes unable to produce interferon-gamma, but that the administration of interferon improves the rates of peritonitis. In an in vitro experiment, Staphylococcus epidermidis, in both its planktonic and biofilm forms, was added to a suspension of peritoneal dialysis effluents, macrophages, and healthy peripheral blood lymphocytes, which were incubated at 37 degrees C for 18 h and then centrifuged. Subsequent levels of interferon-gamma were measured in the supernatants. Three such experiments were done with peritoneal macrophages and dialysis effluents collected from each of the three different patients involved in the study. It was found that little or no interferon-gamma (0.42 +/- 0.17 U/mL) was produced when biofilm bacteria were tested, but significant amounts of interferon-gamma (9.25 +/- 4.63 U/mL) resulted in conjunction with the planktonic form of the same bacteria. To eliminate experimental errors, all conditions were left identical, appropriate control groups were added, and each of the three experiments was duplicated. These in vitro data therefore provide new insight in the role of biofilm in the pathogenesis of recurrent peritonitis in peritoneal dialysis patients. Further clinical studies are required.

Adult↗
PubMed1994

Development of bacterial biofilms on silastic catheter materials in peritoneal dialysis fluid.

A modified Robbins' device was used to monitor the growth of bacteria associated with clinical peritonitis in peritoneal dialysis fluid. To simulate bacterial colonization and biofilm formation on peritoneal catheters, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Escherichia coli were allowed to adhere to silastic disks and were then grown in fresh or used dialysis fluid. Adherent bacteria formed microcolonies and biofilms on silastics within 4 to 24 hours. Our data showed that colonization of the silastic disks was related to the quantity of bacteria and there were significant differences between the growth of adherent bacteria in fresh and used dialysis fluid. Adherent S epidermidis and P aeruginosa grew better in dialysis fluids than adherent E coli. These results suggest that S epidermidis and P aeruginosa are more likely to colonize silastic catheters and to cause catheter-related peritonitis in peritoneal dialysis patients than E coli.

Bacterial Adhesion↗
PubMed1994

Interferon-gamma levels in peritoneal dialysis effluents: relation to peritonitis.

As peritoneal macrophages require Interferon-gamma (IFN-gamma) for bacterial lysis, IFN-gamma levels were measured in peritoneal dialysis effluents. (PDE) by a specific radioimmunoassay. High IFN-gamma levels were found in patients with peritonitis compared to low levels in patients without peritonitis (mean 9.73 +/- 2.63 SE U/ml, N = 39 vs. 0.25 +/- 0.04, N = 32). IFN-gamma levels varied among different bacteria: Staph. aureus (highest: 23.4 +/- 5.7, N = 14), Staph. epidermidis (lower: 3.2 +/- 0.8, N = 13), other gram-positive (1.06 +/- 0.32, N = 6), gram-negative bacteria (lowest: 0.57 +/- 0.30, N = 6). After treatment of peritonitis levels decreased. In corresponding blood and PDE samples, by comparing IFN-gamma levels in 10 peritoneal dialysis patients (5 with peritonitis, 5 without), levels were raised only in PDE of patients with peritonitis, implying local IFN-gamma production. Total lymphocytes, T, B and monocyte subsets in patients' plasma and PDE did not differ, except for a higher number of mononuclear cells in PDE of patients with peritonitis (P < 0.05). Further investigation of in vitro IFN-gamma production in PDE with peritoneal monocytes, syngeneic host lymphocytes, and bacteria showed that Staph. aureus induced the highest levels of IFN-gamma and E. coli the lowest, in experiments with T cell enriched host lymphocytic fractions. We conclude that Staph. aureus peritonitis induces high levels of IFN-gamma in PDE, possibly by a T cell dependent superantigen response.

Adolescent↗
PubMed1994

Silver peritoneal catheters reduce bacterial colonization.

Bacterial colonization potentials by Staphylococcus aureus (Staph. aureus) were determined in silver peritoneal dialysis (PD) catheter materials and were compared to colonization of the same bacteria in silastic catheter materials. The bacteria were colonized in two different experimental systems: In Vitro: In an in vitro biofilm bacterial culture system with a modified Robbins' device (MRD), seven different clinical strains of Staph. aureus were grown in PD effluents on silver or silastic catheter discs, each 0.5 cm in diameter. In identical experimental conditions, reduced bacterial growth was detected in silver catheter discs compared to growth on silastic discs, but the results were not statistically different (p = 0.12). In Vivo: In a rabbit model of PD the, in vivo colonization potential of Staph. aureus was examined in two groups of rabbits using silver (n = 3) and silastic (n = 3) PD catheters. The exit sites of the PD catheters were inoculated with a single strain of Staph. aureus for six days, followed by PD for six days. The rabbits were then sacrificed. After sacrifice, comparison between the bacterial counts of identical segments of silver and silastic catheters showed that there had been a reduction in the growth of Staph. aureus in vivo on silver PD catheters, contrary to the increased growth on the silastic catheters (p < 0.05). Reduced bacterial growth on the silver PD catheters in vivo indicates that the release of silver in tissues over time cause antibacterial effects in vivo. Further in vivo experiments are needed before future clinical use of silver catheters in PD patients.

Animals↗
PubMed1993

A porcine model of Staphylococcus epidermidis catheter-associated infection.

The suitability of using catheterized, partially nephrectomized (uremic) pigs to study catheter-associated infection in peritoneal dialysis was investigated. In some pigs, an inoculum of 10(9) cfu of Staphylococcus epidermidis ATCC 35984 was deposited around the catheter exit site and the organism was allowed to colonize over 21 days. The strain was recoverable from tissues and catheter samples at various locations along the catheter tract from inoculated pigs at postmortem examination. Uninoculated control catheters were colonized to a significantly lesser degree and by various other staphylococcal species. Immune response by inoculated pigs toward catheter-associated bacteria was indicated by a significant increase in serum antistaphylococcal IgG concentration and an increased percentage of peripheral polymorphonuclear leukocytes. Uremia had no significant effect on serologic response. Immunoblotting against S. epidermidis lysostaphin-extracted proteins showed that although incubation with inoculated group antisera produced more intense banding and reacted to a wider range of protein than did antisera from uninoculated controls, common antigenic proteins among the groups were found.

Animals↗
PubMed1993

Effect of growth conditions on expression and antigenicity of Staphylococcus epidermidis RP62A cell envelope proteins.

Staphylococcus epidermidis RP62A (ATCC 35984) was grown in tryptic soy broth (TSB), iron-depleted TSB (TSB-Fe), iron-reconstituted TSB-Fe (TSB+Fe), a chemically defined medium, and fetal calf serum (FCS) and on silastic disks in chambers that were sutured to the pig peritoneal wall. Bacterial cell wall proteins were extracted by digestion with recombinant lysostaphin, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and detected by silver staining. Cell wall proteins from TSB-, chemically defined medium-, or FCS-grown cells had a complex profile of greater than 25 protein bands spanning the full molecular mass range. By contrast, a digest obtained from in vivo-grown cells had only five major proteins of 40 kDa or greater. Proteins of 130 and 106 kDa were present in the cell envelopes of TSB-Fe- and in vivo-grown cells but not in those grown in TSB or TSB+Fe. A 43-kDa protein expressed by in vitro-grown cells and 52- and 96-kDa proteins expressed by in vivo-grown cells reacted with antisera from pigs with the chamber implants and from catheterized, paracatheter-inoculated pigs but not with hyperimmune sera from pigs immunized with TSB-grown cells. The data indicate that S. epidermidis, growing under in vivo conditions, expresses antigens distinct from those that are grown in vitro.

Animals↗
PubMed1992

Significant reduction of peritonitis rate by the use of Twin-bag system in a Canadian regional CAPD program.

In a regional CAPD program in Northern Alberta, Canada, the peritonitis rates among patients undergoing CAPD treatment were quite high: 1/8.3 and 1/7.4 per patient month from a population of 75 and 76 patients in 1989 and 1990 respectively. Our patient population is comprised of different ethnic groups, separated widely from the dialysis centre; over half of them are above the age of 60 years. As it is not possible to change the patient characteristics in our centre, we switched to the Twin-bag disconnect system in 83 out of a total of 103 patients in 1991. With this change our overall peritonitis rate has significantly improved to 1/14 per patient months and 1/17 per patient months in patients using the Twin-bag system. This improvement in the peritonitis rate has occurred without any change in our patient characteristics. We find the improvement in our peritonitis rate is due to the use of the new Twin-bag system, which provides total disconnection with no spikes and thereby reduces peritonitis due to touch contamination.

Humans↗
PubMed1991

Catheter biofilms and recurrent CAPD peritonitis.

To study the significance of biofilm bacteria in CAPD peritonitis, in a preliminary study, we compared the growth of planktonic and biofilm bacteria by parallel cultures of the same PD effluent in 14 patients with CAPD-associated peritonitis. Planktonic bacteria were isolated by routine microbiologic culture techniques and biofilm bacteria by the use of a modified Robbins' device (MRD). Antibiotic sensitivity or MIC's of bacterial strains isolated by the two techniques were compared. This comparison of the IC identified a subgroup of patients who developed recurrent antibiotic resistant biofilm-induced peritonitis and their peritoneal catheters were subsequently removed.

Adult↗
PubMed1991

Use of streptokinase or urokinase in recurrent CAPD peritonitis.

In patients undergoing CAPD treatment, removal of peritoneal catheters has become a standard practice after two or more episodes of recurrent peritonitis which are refractory to antibiotic treatment. Immediate replacement of peritoneal catheters is not always safe in the presence of active peritonitis. Temporary institution of hemodialysis treatment in some of these patients may also be impossible because of unstable hemodynamic states or loss of vascular access sites. Successful continuation of CAPD treatment in some of these patients has been reported by using intraperitoneal (IP) administration of fibrinolytic agents such as streptokinase or urokinase as an adjunctive therapy to antibiotic treatment and as an outpatient procedure. Although numbers of cases reported are few in the literature and controlled studies in large numbers of patients are lacking, these reports emphasize the safety of IP use of these agents without any major systemic adverse effects. The reports are reviewed here to provide some practical guidelines for safe use of these agents in selected patients with recurrent CAPD-associated peritonitis.

Humans↗
PubMed1990

Pathogenesis of chronic bacterial prostatitis in an animal model.

A reproducible rat model of chronic bacterial prostatitis was developed using a defined bacterial pathogen (Escherichia coli) to study the pathogenesis and persistence of chronic bacterial prostatitis. The progression of inflammation and its consequences from acute to chronic prostatitis were documented with microbiological, histological, ultrastructural and immunological data. Chronic bacterial prostatitis in this model was associated with sparse glycocalix-enclosed protected bacterial microcolonies within the prostatic acini and ducts which appeared to stimulate a persistent local and systemic immunological reaction resulting in chronic inflammation of the gland. This model has many striking similarities to the natural history of human chronic bacterial prostatitis.

Animals↗