Ultrastructural study of microbiologic colonization of urinary catheters

We examined ten urinary catheters, associated with catheter-related urinary tract infections, by scanning and transmission electron microscopy to study the morphology of bacterial adherence. We confirmed that the bacteria associated with catheter-associated urinary tract infections grow in glycocalyx-enclosed microcolonies in a biofilm on the catheter surface. The bacterial populations demonstrated a heterogeneity that was not evident from the culture results, and it was demonstrated that only a small proportion of the microorganisms, including fungi, identified morphologically by scanning or transmission electron microscopy are recovered by routine culture methods. The persistence of the bacterial pathogens in catheter-associated infection, even in the face of antibiotic treatment, may be attributed to their adherent mode of growth in protected biofilms and their production of extensive enveloping anionic glycocalyces.

Infection-induced struvite urolithiasis in rats

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Carcinoids of the kidney: case report and literature review

Primary carcinoids of the kidney are very rare, only 10 cases having been reported in the literature. The authors report a case of primary renal carcinoid in a 50-year-old woman. A radical nephrectomy with lymphadenectomy was successfully performed and there was no residual or recurrent tumour at 2-year follow-up. A review of the reported cases revealed a variable, nonspecific presentation. Most laboratory tests were non-contributory except for urinalysis. When a renal carcinoid is diagnosed, a search should be made for a possible primary elsewhere. Primary renal carcinoid does exhibit malignant behaviour. It should be managed by radical nephrectomy with retroperitoneal lymphadenectomy.

Amdinocillin treatment of catheter-associated bacteriuria in rabbits

The effect of the beta-lactam antibiotic, amdinocillin, on the bacterial biofilm adherent to the Foley catheter surface, the bacterial microcolonies attached to the urinary bladder mucosa, and on planktonic bacteria in the urine was studied in a rabbit model of the closed urinary catheter drainage system. Progressively increasing the dose of antibiotic in this experimental catheter-associated urinary tract infection model first eliminated the bacterial population adherent to the bladder mucosa and then the planktonic population in the urine. The bacterial biofilm on the Foley catheter could be eradicated only by the highest dose of antibiotic (400 mg/kg). Scanning electron microscopy showed a gradual deterioration of bacterial biofilm and reduction in bacterial numbers with increasing antibiotic dosages. These data suggest that antibiotics used in short-term catheterization may reduce the serious sequelae associated with catheter-related infections by clearing the potentially dangerous bladder mucosal bacterial populations and urine planktonic bacteria.

Observations of the ultrastructure of infected kidney stones

Struvite stones are formed as the result of urinary tract infection by urease-producing bacteria. Ultrastructural examination of calculi removed from a patient revealed bacteria incorporated throughout the stone matrix. Exopolysaccharide stained by ruthenium red was associated with most of the bacteria, but it represented only a small portion of the organic matrix in the stone. Localised deposits of calcium and phosphorus, components of carbonate-apatite, and magnesium, a struvite component, were detected in close proximity to the cells. Histochemical examinations revealed that several of the gram-negative bacteria within the stone matrix possessed high levels of urease activity. We propose that bacterial slime production, intimately involved in the initiation of stone matrix deposition, is less prominent in mature stones because of the increased incorporation of host-derived mucoproteins and mucopolysaccharides.

Evaluation of the retrograde contamination guard in a bacteriologically challenged rabbit model

We compared a newly developed closed urinary drainage system incorporating a retrograde contamination guard (RCG) with the conventional closed drainage system. The new system contains a solid bactericide (povidone iodine) pellet enclosed in a porous cartridge at the drain port of the urine collection bag. A catheterised rabbit model was used. The urine drainage bags were challenged daily for 8 days with an auxotrophically marked uropathogenic strain of Escherichia coli at the outlet tube. The bag urine was infected with the marked organism in 10 of the 11 rabbits in the control group (conventional collection bags) in 3.8 +/- 1.03 days and in only 1 of the 13 rabbits fitted with the RCG. The RCG effectively prevents contamination of the urine drainage bag and thus may play an important role in reducing the incidence of nosocomial urinary tract infections.

Incidence and importance of bacteriuria in postoperative, short-term urinary catheterization

The frequency and importance of bacteriuria in patients requiring short-term postoperative catheterization (24 to 48 hours) is unknown. From a prospective, controlled study of 100 patients requiring catheterization postoperatively, the authors determined that there was a definite risk (6%) of bacteriuria; however, a symptomatic urinary tract infection developed in only 1% of the patients. There was no advantage to using either a latex or silicone catheter. It appears that the risk of symptomatic bacteriuria in this group of patients is very low when a closed urinary drainage system is used under strict, sterile conditions of catheter insertion and with meticulous ongoing catheter care.

Peritonitis in peritoneal dialysis: bacterial colonization by biofilm spread along the catheter surface

We have used modern techniques of direct microscopic examination and quantitative bacterial recovery to show the existence of a route of bacterial colonization along the external and internal surfaces of Tenckhoff catheters implanted in experimental animals. The external route of progressive bacterial colonization extends from the cutaneous exit site through the dacron cuff and into the peritoneum. Bacterial growth along this route consists primarily of glycocalyx enclosed bacterial biofilms adherent to catheter and tissue surfaces, and this surface colonization may or may not give rise to peritoneal infection in which free-living bacteria are found in the peritoneal fluid. The rate of this progressive bacterial colonization depends on the degree of bacterial contamination of the exit site at the time of implantation. Exit site sterilization (hibitane) delays the process while inoculation with rabbit skin strains of Staphylococcus epidermidis accelerates it. Even with optimal implantation techniques, bacterial colonization proceeds via this subcutaneous route so that most Tenckhoff catheter surfaces are covered with a bacterial biofilm, consisting predominantly of gram positive cocci, within three weeks after the implantation of these devices. The rate of bacterial biofilm development on both surfaces of these Tenckhoff catheters, the bacterial colonization of peritoneal tissues, and the dissemination of bacteria into the peritoneal fluid are all significantly accelerated by dialysis in this experimental animal model of continuous ambulatory peritoneal dialysis (CAPD).

Cavernous hemangiomas of the bladder in the pediatric age group

We describe 2 children with bladder hemangiomas. The diagnosis, pathology and treatment of these lesions in children are reviewed.

Percutaneous endourologic approach for transitional cell carcinoma of the renal pelvis

A small mass was detected in the renal pelvis during investigation for hypertension and diminished renal function. Its presence was confirmed by computed tomography. Since the patient was not a candidate for nephrectomy, interventional percutaneous techniques were used to confirm the diagnosis of transitional cell carcinoma and ultimately permit endourologic access for resection and cure.

A theoretical model of loading and eminence development of the postnatal human temporomandibular joint

The objectives of the present study were to characterize the loading of the immature TMJ, and to develop a theoretical model to explain the relationship between joint loading and development of the eminence of the human TMJ. The osteological remains of forty individuals, ages ranging from birth to twenty years, were used to provide metric coordinates of the three-dimensional relationships of the anatomy of the biting apparatus. The data were used, in a numerical model of TMJ loading (Smith et al., 1986), to calculate the magnitudes and directions of condylar loading. The following conclusions were drawn: (i) static equilibrium cannot be satisfied unless the immature TMJ is loaded; (ii) in the neonate, the direction of condylar loading is approximately vertical but, as the child matures, the angle of condylar loading becomes more oblique; and (iii) evidence is given in support of the hypothesis that early development of the eminence is consequent upon the stimulation of bone growth by the appropriate position and timing of loading of the immature condyle on the temporal component of the joint.

Eminence development of the postnatal human temporomandibular joint

The objective of this study was to analyze postnatal eminence development quantitatively, as a first step in defining the relationship between loading of the TMJ and eminence development. A sample of human osteological remains provided the temporal bones of forty-nine (49) individuals of ages between birth and twenty years. An angular measurement technique permitted quantification of the degree of eminence development of each individual. It was concluded that: (i) the TMJ eminence reaches more than 50% of mature size, and exhibits mature morphology, by the time of completion of eruption of the primary dentition; (ii) the maximum velocity of development of the eminence takes place before three years of age; and (iii) the velocity of development of the eminence is reduced at about five years of age, and slowly diminishes to zero by the middle to late teens.

The ecology and pathogenicity of urease-producing bacteria in the urinary tract

Urease activity is a physiological function of many bacteria that enables these organisms to utilize urea as a source of nitrogen. The association of ureolytic bacteria with human or animal hosts varies widely from a commensal relationship as demonstrated with skin microflora, a symbiotic relationship in the gastrointestinal tract, to a pathogenic relationship in the urinary tract. Since similar or identical species of bacteria such as Staphylococcus aureus are found in all three environments, the effect of urease activity on the host must be solely a function of the environment of these organisms. In this review, the importance of urease to bacteria is discussed, identifying the gastrointestinal tract as a major reservoir of ureolytic bacteria and investigating the urinary tract environment and the infectious struvite stone production that often accompanies urease-producing bacteria there. Finally, an infection model is presented which explains the development and growth of these urinary calculi and their remarkable persistence in spite of modern urological treatments.

The use of a radiorespirometric assay for testing the antibiotic sensitivity of catheter-associated bacteria

A 14C-radiorespirometric assay was used to show the sensitivity of fixed-film (sessile), catheter-associated and free-living (planktonic) cells of Pseudomonas aeruginosa to varying concentrations (100 micrograms/mL to 1000 micrograms/mL) tobramycin sulfate. This strain of P. aeruginosa has an MIC of 0.6 microgram/ml and an MBC of 50 micrograms/mL when tested by conventional methods. When 14C-glutamic acid was used as a substrate in this radiorespirometric assay, it could be completed in less than one hour and planktonic samples showed a significant reduction in mineralization activity (evolution of 14CO2) within eight hours of the antibiotic challenge. These changes in respiratory activity appeared to be dose and time dependent. Within 18 hr. at 1000 micrograms/mL, there was no significant residual respiratory activity in planktonic samples. Some residual respiratory activity was detected, however, in samples exposed to 100 micrograms/mL for 36 hours. The mineralization activity of sessile catheter-associated bacteria was unaffected by four hr. and eight hr. exposures to 1000 micrograms/mL of the antibiotic. A significant reduction in respiratory activity was recorded in catheter samples exposed for 18 hr. or more at each concentration examined. Unlike the planktonic samples, however, the antibiotic challenge failed to eradicate the metabolic activity of the attached bacteria. Antibiotic stressed, catheter-associated bacteria transferred to a post-exposure enrichment broth showed a limited ability to re-establish respiratory activity. This apparent recovery was limited to antibiotic exposures less than 24 hr. and was not observed in planktonic samples. The radioisotopic assay is a non-culture method which can be used to assess the antibiotic sensitivity of both planktonic bacteria and "in situ" biofilm populations. Clinically, it can be used to demonstrate that some adherent biofilm bacteria can survive the exposure to antibiotics that is achieved in routine chemotherapy.

Percutaneous renal surgery

Percutaneous renal surgery was developed initially to remove renal calculi safely without the attendant morbidity of standard open pyelolithotomy. As familiarity with techniques has been obtained, other intrarenal diseases have been treated using this approach. This report reviews the current applications of percutaneous renal surgery and discusses its relation to extracorporeal shock-wave lithotripsy in the management of renal calculi.

Bacterial colonization of intestinal urinary conduit diversion: a morphologic and bacteriologic experimental study

Cutaneous diversion of the urine through intestinal conduits results in bacteriuria with uropathogenic organisms in up to 80% of patients, many of whom suffer pyelonephritis. Analysis of the bacteriologic data from daily sampling at multiple sites and scanning and transmission electron microscopic studies of sequential loop and autopsy specimens in rabbits with functioning colonic conduits indicate that the pyelonephritis evolves in sequential stages of microbial colonization. Using these data on the natural progression of bacterial infection, we can rationally test the ability of strains of bacteria indigenous to the conduit of this animal model to prevent uropathogenic colonization of the conduit.

In vivo coefficient of kinetic friction: study of urinary catheter biocompatibility

An animal model was developed to measure objectively the in vivo intrinsic coefficient of kinetic friction (COFk) of various catheter materials. Uncoated red rubber catheters had the highest COFk of the three materials tested. The Biocath catheter exhibited less COFk when compared with the standard silicone catheter. Although the etiology of urethral strictures is multifactorial, better biocompatibility as measured by in vivo COFk may be an important factor in the inevitable urethral trauma and irritation associated with indwelling catheterization and possibly with postcatheterization urethral stricture formation.

An ecological study of infected urinary stone genesis in an animal model

Direct molecular and morphological techniques of modern microbiology were used to monitor the sequential development of bacterial microcolonies and biofilms in a rat model of urinary infection and to demonstrate that the urease activity of the infecting organisms sets in course a series of reactions in which struvite and apatite crystals develop within the matrix of the enlarging bacterial aggregate. This forms multiple stone nidi on the uroepithelial surface upon which succeeding bacterial biofilms develop and with the incorporation of other urine components, such as urinary mucroproteins, establishes a matrix skeleton that becomes mineralised, thus allowing for the growth of the stone in concentric layers. To arrive at this hypothesis, we studied infection stone genesis using a newly developed model for infection-induced bladder stone formation in the rat. We examined in detail the sequential events in the evolving microbial ecology of progressive struvite calculogenesis, using conventional microbiological techniques, direct ultrastructural observation, newly developed ultrastructural cytochemical localisation techniques and immunological procedures for stabilisation of the biofilm glycocalix and stone matrix in the rat model. It was concluded that the organic glycocalix material secreted by the associated bacteria comprises a substantial and aetiologically important part of the infection stone calculogenesis and matrix production.

Ultrastructural microbiology of infected urinary stone

Scanning and transmission electron microscopy of an antibiotic-treated infected urinary stone demonstrates a thick bacterial biofilm adhering to the surface of the stone. Cultures of the crushed calculi indicated the viability of the bacteria. Exopolysaccharide secreted by the bacteria develops a matrix or glycocalyx that appears to protect the biofilm-forming sessile bacteria from antibiotics.

Histochemical and biochemical urease localization in the periplasm and outer membrane of two Proteus mirabilis strains

Proteus mirabilis, a gram-negative bacillus, is often implicated in the formation of infectious kidney stones. As ureolytic activity of this organism is thought to play a major role in its pathogenesis, we adapted our recently described urease localization technique to visualize urease activity in vivo. Urease activity was ultrastructurally localized in two clinically isolated P. mirabilis strains by precipitating the enzymatic reaction product (ammonia) with sodium tetraphenylboron. Subsequent silver staining of the cells revealed urease activity to be predominantly associated with the periplasm and outer membranes of each strain. Biochemical measurements of urease activity in P. mirabilis cell fractions correlated well with histochemical observations in that the majority of urease activity was associated with the periplasm. Membrane-bound urease activity of these strains was associated mainly with the peptidoglycan in the detergent-insoluble (outer membrane) fraction.

Bacterial biofilm in persistent penile prosthesis-associated infection

The ultrastructural microbiology of 2 cases of infection associated with rigid penile prostheses was studied. The persistence of these infections appeared to be related to the mode of growth of the bacteria in protected biofilms adherent to the inert surface of the prosthesis.

Clinical relevance of plasma testosterone and prolactin changes in advanced cancer of prostate treated with diethylstilbestrol or estramustine phosphate

We have investigated a group of 30 patients with newly diagnosed metastatic carcinoma of the prostate who were randomly assigned to receive, as primary treatment, either diethylstilbestrol (DES) or estramustine phosphate (Emcyt). Clinical response was assessed following the guidelines of the National Prostatic Cancer Project and the Eastern Cooperative Oncology Group. Effective reduction in the levels of androgens was noted in all patients in both groups regardless of response. During the follow-up period (ranging between 2-5 years) relapses were noted despite the presence of androgen levels at or below castrate values. The most relevant endocrine observation was the detection of early elevations in serum prolactin in a majority of patients. It was noted, however, that those patients in whom hyperprolactinemia did not occur or appeared only briefly at the beginning of therapy, experienced a prolonged, symptom-free survival. Persistent hyperprolactinemia, on the other hand, carried an ominous prognosis. The differences in survival between normoprolactinemic and hyperprolactinemic groups carried statistical significance.

Catheter-associated bacteriuria. An experimental study

A bacteriologically-stressed catheterized animal model was developed to evaluate the comparative importance of the intraluminal versus the extraluminal route of catheter-acquired urinary tract infections. This study indicated that in short-term catheterization (less than 7 days), contamination of the drainage spout or accidental disconnection of the drainage tube resulted in bacteriuria within a short time (32-48 hours). If a strict sterile closed drainage system was maintained, the extraluminal route assumed more importance in the development of bacteriuria, however this pathway was considerably slower (72-168 hours). It appeared that catheter-associated bacteriuria results from ascending bacterial colonization within glycocalyx-enclosed biofilm on the inside and/or outside surfaces of the catheter and drainage systems. Development of a biomaterial that inhibits bacterial adherence and does not allow upstream colonization of bacteria on the catheter drainage system would significantly influence the rate of catheter-acquired urinary tract infection.

An in vitro ultrastructural study of infectious kidney stone genesis

A ureolytic strain of Proteus mirabilis, isolated from a patient with infectious kidney stones, produced struvite (MgNH4PO4 X 6 H2O) and apatite [Ca10(PO4)6CO3] crystals in vitro when grown in artificial urine. Surface-attached crystals were encased in a slime-like layer. Scanning electron microscopy revealed that surfaces submerged in the artificial urine were colonized by P. mirabilis. Bacteria-associated crystals appeared soon after colonization and eventually became coated with an amorphous substance. Energy-dispersive X-ray analysis of these crystals revealed the presence of Mg, Ca, and P which are major components of struvite and apatite. Transmission electron microscopy of surface scrapings revealed that the glycocalyx of P. mirabilis contained a large number of crystals. Based on these observations and previous work, a theory for infectious renal calculogenesis is proposed. The kidney is initially colonized by invading ureolytic pathogens. These pathogens secrete copious amounts of glycocalyx which facilitates adhesion of the organisms to the kidney, provides protection for these bacteria, and serves to bind struvite and apatite crystals that result from bacterial urease activity. Growth of these calcified microcolonies into mature stones is characterized by continued bacterial growth, incorporation of urinary mucoproteins into the matrix along with bacterial glycocalyx, and a continued deposition of struvite and apatite crystals due to the high pH. The mature stone, in effect, represents an enlarged "fossilized" bacterial microcolony.

Rapid method for detection of adherent bacteria on Foley urinary catheters

An accurate, rapid, and inexpensive method was developed for detecting and enumerating bacteria adherent to Foley urinary catheters based on malachite green staining of acridine orange-prestained specimens. This method has proven to be quick and reliable and will find application in quantitative studies of biomaterial-related sepsis.

Tobramycin resistance of Pseudomonas aeruginosa cells growing as a biofilm on urinary catheter material

When disks of urinary catheter material were exposed to the flow of artificial urine containing cells of Pseudomonas aeruginosa, a thick adherent biofilm, composed of these bacteria and of their exopolysaccharide products, developed on the latex surface within 8 h. After this colonization, sterile artificial urine containing 1,000 micrograms of tobramycin per ml was flowed past this established biofilm, and a significant proportion of the bacterial cells within the biofilm were found to be still viable after 12 h of exposure to this very high concentration of aminoglycoside antibiotic. Planktonic (floating) cells taken from the test system just before the exposure of the biofilm to the antibiotic were completely killed by 50 micrograms of tobramycin per ml. The MIC of tobramycin for cells taken from the seeding cultures before colonization of the catheter material, and for surviving cells recovered directly from the tobramycin-treated biofilm, was found to be 0.4 micrograms/ml when dispersed cells were assayed by standard methods. These data indicate that growth within thick adherent biofilms confers a measure of tobramycin resistance on cells of P. aeruginosa.

Ultrastructural microbial ecology of infection-induced urinary stones

With advanced techniques of scanning and transmission electron microscopy we studied the ultrastructural ecology of bacteria associated with struvite calculi on catheter surfaces, and in the bladder, ureter and renal pelvis. These detailed morphological data indicate that the interstices, core and external surface of such struvite aggregates contain large numbers of bacterial cells that grow as microcolonies and thick biofilms within extensive fibrous organic matrices. These bacterial cells and their secreted products (glycocalyx or biofilm matrix) appear to provide initial foci for crystal development and aggregation of crystals to form macroscopic struvite stones. The protective glycocalyx-enclosed microcolonial mode of bacterial growth also may explain the relative resistance to antibiotics observed in bacteria associated with infection stones.

Antibiotic resistance of Pseudomonas aeruginosa colonizing a urinary catheter in vitro

A modified Robbins Device was used to establish coherent biofilms of Pseudomonas aeruginosa on the surface of catheter material in an artificial urine milieu and the ability of an antibiotic to penetrate the biofilm and kill the enclosed bacteria was assessed. The Pseudomonas aeruginosa strain used had been isolated from a patient with urinary tract infection. Although planktonic (floating) cells of the Pseudomonas aeruginosa strain were inhibited by less than 1 mg/l of tobramycin and killed by 50 mg/l, contact with 1,000 mg/l of tobramycin for 12 h failed to kill all the sessile (adherent) bacteria in the biofilms on the surface of the catheter material. Surviving sessile bacteria recovered directly from the exposure to 1,000 mg/l of tobramycin were inhibited by 0.4 mg/l of this agent when tested as dispersed planktonic cells by standard MIC methods. It is suggested that growth within thick adherent biofilms confers upon cells of Pseudomonas aeruginosa a large measure of resistance to aminoglycosides and other antibiotics that may help to explain the frequent failure of antibiotic chemotherapy in catheter-associated urinary tract infections.

Electron microscopic study of an infected Foley catheter

A scanning and transmission electron microscopic study was made of material from the surface of a Foley catheter removed from an 87-year-old woman with antibiotic-resistant bacteriuria. A thick, adherent bacterial biofilm was found. The sessile adherent bacteria were surrounded by an extensive exopolysaccharide glycocalyx that appears to be fundamental in the pathogenesis of catheter-associated urinary tract infections and their resistance to systemic antibiotic therapy.

Endocrine dysfunction in impotence: incidence, significance and cost-effective screening

A comprehensive evaluation of impotence includes assessment of the functional integrity of the hypothalamic-pituitary-gonadal axis. However, little is known about the incidence or significance of hormonal abnormalities in an unselected group of men with erectile failure. A systematic multidisciplinary, multidimensional assessment of 256 impotent men showed clearly an organic etiology in 35.9 per cent, psychogenic in 38.3 per cent and mixed or uncertain in 25.8 per cent. The incidence of hypothalamic-pituitary-gonadal axis abnormalities in the entire group was 17.5 per cent but in only 12.1 per cent did they contribute clearly to erectile dysfunction. A cost-effective screening of the endocrine system in impotent men includes a thorough history and physical examination, and a serum testosterone determination. More sophisticated and expensive investigations should be reserved for patients with a history of drug use known to induce hormonal abnormalities or with somatic evidence of hypogonadism and a depressed serum testosterone level.

Necrotizing fasciitis of the male genitalia (Fournier's gangrene)

Necrotizing fasciitis of the male genitalia was first described 100 years ago. Although the mortality of this condition has generally been high, the last few years have seen dramatic therapeutic improvements. This paper details the treatment of necrotizing fasciitis in two patients and describes a plan of management, which includes early diagnosis, vigorous antibiotic treatment and radical débridement of the necrotic tissues, that should improve the prognosis of the condition.