New approaches to the treatment of urinary tract infection.

The term urinary tract infection encompasses a broad range of clinical entities, each with its own pathology and each requiring its own form of treatment. There are at least four different modes in which antimicrobial therapy may be prescribed for urinary tract infection: single-dose therapy aimed at patients with superficial mucosal infection; a conventional seven- to 14-day course of therapy; a prolonged four- to six-week course of therapy for patients with deep tissue infection; and low-dose prophylactic therapy. Increasingly, the response to single-dose therapy is being utilized to delineate the mode of therapy needed by a patient. Patients with underlying renal disease and/or structural abnormalities of the urinary tract are prone to the development of recurrent urinary tract infection, frequently with bacteria resistant to antimicrobial agents conventionally employed to treat the infection. There has been a steady increase, even among otherwise normal persons with urinary tract infection, in the level of antimicrobial resistance exhibited by bacterial uropathogens to the drugs commonly used to treat these infections. The quinolones in general, and ciprofloxacin in particular, appear to be very promising for the treatment of urinary tract infection. It will be important to evaluate the performance of this drug in the four different therapeutic modes and in patients with renal dysfunction or anatomic abnormalities of the urinary tract.

Infection in the renal transplant recipient.

The incidence of infection in the renal transplant patient is directly related to the net immunosuppressive effect achieved and the duration of time over which this therapy is administered. A second major factor in the causation of infections in this population is the nosocomial hazards to which these patients are exposed, ranging from invasive instrumentation to environmental contamination with Aspergillus species, Legionella pneumophila, Pseudomonas aeruginosa and other microbial pathogens. Careful surveillance is necessary to identify and eliminate such nosocomial sources of infection. The major types of infection observed can be categorized according to the time period post-transplant in which they occur: postsurgical bacterial infection in the first month after transplantation; opportunistic infection, with cytomegalovirus playing a major role, and transplant pyelonephritis in the period one to four months post-transplant; and a mixture of conventional and opportunistic infections in the last post-transplant period. Conventional infection in this late period occurs primarily in patients with good renal function who are receiving minimal immunosuppressive therapy; opportunistic infection occurs primarily in patients with poor renal function who are receiving higher levels of immunosuppression.

IGA nephropathy in HLA-identical siblings.

This report describes a patient with end stage IgA nephropathy who received a renal transplant from his asymptomatic HLA-identical brother. A biopsy of the donor kidney performed at the time of transplantation showed evidence of widespread electron-dense mesangial deposits. On immunofluorescence these deposits stained with IgA, documenting clinically occult IgA nephropathy in this otherwise healthy donor. These findings are of particular interest in view of the association of IgA nephropathy with the HLA-Bw35 alloantigen, and raise the possibility that asymptomatic disease, already present in a donor kidney, may have accounted for what has previously been called "recurrence" of this disease in renal allograft recipients.

Impact of hepatitis on renal transplantation.

In order to delineate the incidence, etiology, and impact of liver disease in renal transplant patients, we reviewed 405 consecutive transplants performed between 1970 and 1980. Hepatic dysfunction of at least 2 weeks' duration was diagnosed in 42 patients (10.4%). Of 28 patients acquiring hepatitis in the first post-transplant year, 26 (92.8%) developed chronic hepatitis; of 14 acquiring hepatitis after the first year, 9 (64.2%) developed chronic hepatitis. Of the 42 patients, 19 (45.2%) died, as compared with 16% of the nonhepatitis patients (P less than 0.001). Only one of these patients died of liver failure, with 15 of the 19 (78.9%) dying of extrahepatic infection. In addition, 12 of the 23 survivors (52.1%) suffered life-threatening infections from which they recovered, as compared with 20% of the nonhepatitis patients (P less than 0.01). Conversely, graft survival was significantly increased among the hepatitis patients (73% 1-year cadaveric allograft survival as compared with 50% for the nonhepatitis patients (P less than 0.01)). The etiology of the liver disease was identified in the minority of patients: 5 (11.9%) with hepatitis B, with none occurring since 1973; 10 (23.8%) with evidence of cytomegalovirus infection; and 1 (2.3%) with azathioprine toxicity. We conclude that the major cause of liver disease in renal transplant patients is non-A, non-B hepatitis, and furthermore, that this disease has a marked immunosuppressing effect resulting in increased allograft survival and a marked increase of life-threatening extrahepatic infection.

Vascular endothelial function in cyclosporine and tacrolimus treated renal transplant recipients.

BACKGROUND: Endothelial dysfunction is an early key event in the development of arteriosclerotic cardiovascular disease (ASCVD), thus an early marker of subclinical ASCVD. Endothelial function is impaired in renal transplant recipients (RTR) treated with cyclosporine (CyA). Tacrolimus is associated with less hyperlipidemia and hypertension than CyA, however, there are no data on endothelial function in tacrolimus-treated RTR. METHODS: High-resolution brachial ultrasonography was used to assess endothelium-dependent dilatation (EDD), and endothelium-independent dilatation (EID) in 20 stable RTR and a control group of 10 healthy subjects without clinical evidence of ASCVD. The RTR group included patients receiving CyA (n=10) and tacrolimus (n=10). EDD and EID were measured as percent increase in brachial artery diameter in response to reactive hyperemia and nitroglycerin, respectively. RESULTS AND CONCLUSIONS: EDD was significantly lower in RTR versus controls (1.7+/-0.7 vs. 7.3+/-0.7%, P<0.0001), whereas EID was similar in the two groups. No significant differences were found in EDD or in EID between CyA- and tacrolimus-treated RTR. Glomerular filtration rate, plasma homocysteine, blood pressure, and lipid profiles were similar in CyA- and tacrolimus-treated RTR.

Effect of oral acyclovir or ganciclovir therapy after preemptive intravenous ganciclovir therapy to prevent cytomegalovirus disease in cytomegalovirus seropositive renal and liver transplant recipients receiving antilymphocyte antibody therapy.

BACKGROUND: Organ transplant recipients who are seropositive for cytomegalovirus (CMV) and who are treated with antilymphocyte antibody (ALA) therapy have a high rate of symptomatic CMV disease. The intravenous administration of ganciclovir therapy once daily during ALA therapy decreased the incidence from 24% to 10% in patients receiving ALA as an induction therapy and from 64% to 22% in those treated for rejection. The present study was undertaken to determine whether a more intensive and sustained antiviral regimen could be more effective. METHODS: From April 1995 to December 1997, all CMV seropositive renal and liver transplant recipients who received ALA therapy were treated with intravenously administered ganciclovir (5 mg/kg/day with dose adjusted for renal dysfunction) for the length of ALA therapy and then with orally administered acyclovir (400 mg three times/day) or ganciclovir (1 gm twice/day) for 3 to 4 months. The incidence of CMV viremia and of CMV disease was determined during the 6 months after completion of ALA therapy. RESULTS: Forty-one patients (35 renal and 6 liver transplant recipients) were studied. CMV disease occurred in 2 patients (4.9%), both of whom were treated for rejection; it occurred in 1 of 21 patients (4.8%) treated with orally administered acyclovir, and in 1 of 20 patients (5%) treated with orally administered ganciclovir. The only patient who developed CMV disease in the ganciclovir group had received only 26 days of oral antiviral therapy. No CMV disease was documented in the group of patients receiving ALA therapy as induction therapy. CMV viremia occurred in three patients in the acyclovir group (14.3%) and in one patient in the ganciclovir group (5%). Among renal transplant recipients only, 1 of 35 patients developed CMV disease (2.9%) and no case of CMV disease was documented in patients treated with orally administered ganciclovir. All six patients receiving two courses of ALA therapy each were free of CMV disease. Toxicity of the regimen was minimal, and antiviral resistance did not develop. CONCLUSIONS: Preemptive antiviral therapy with intravenously administered ganciclovir during ALA therapy and then orally administered ganciclovir for 3 to 4 months provides virtually complete protection against the excessive rate of CMV disease that occurs in CMV seropositive allograft recipients receiving ALA therapy.

Immunogenicity of hepatitis B vaccine in renal transplant recipients.

To evaluate the immunogenicity of hepatitis B vaccine in renal transplant recipients, we administered three 40-microgram doses of vaccine to 17 patients who had previously undergone transplantation and were on immunosuppressive therapy. Life-table analysis revealed a cumulative antibody response rate of only 17.6% at 12 months, and the three responders had low titers of antibody to hepatitis B surface antigen. There were no serious adverse effects and no episodes of graft rejection in responders or nonresponders. In addition, the ratio of helper/inducer (T4) to suppressor/cytotoxic (T8) T cells in vaccinees bore no relationship to the immunogenicity of the vaccine. These data indicate that hepatitis B vaccine is weakly immunogenic in renal transplant recipients and illustrate the need for vaccination prior to transplantation for maximal protection against hepatitis B virus infection.

Multicenter seroepidemiologic study of the impact of cytomegalovirus infection on renal transplantation.

The effects of cytomegalovirus (CMV) infection on patient and allograft survival were determined in 1245 renal transplant recipients from 46 transplant centers. When an antilymphocyte preparation was administered to cadaveric allograft recipients, those at risk for primary CMV had a worse outcome than similar patients treated with prednisone and azathioprine (53.1% alive at 6 months with a functioning allograft vs. 70.8%, P = .05) or patients at risk for reactivation CMV (53.1% vs. 71.1%, P = .035). Patients at risk for reactivation CMV had a better outcome if they received an antilymphocyte preparation (71.1% vs. 60.8%, P less than .01). The type of immunosuppression had no effect on patients without CMV. Living-related donor transplantation was not significantly influenced by CMV or type of immunosuppression. We conclude that CMV infection is strongly influenced by the form of immunosuppression employed, and that both are important determinants of the outcome of cadaveric renal transplantation.

Diagnosis of tubular injury in renal transplant patients by a urinary assay for a proximal tubular antigen, the adenosine-deaminase-binding protein.

Two murine monoclonal antibodies (URO-4 and URO-4a)--which detect different epitopes of a proximal tubular cell glycoprotein antigen, the adenosine-deaminase-binding protein (ABP)--have been formatted into a sandwich enzyme immunoassay for detection of ABP in the urine. Serial urine samples from 34 renal transplant patients during the first six months posttransplant were analyzed to determine the correlation of this test with clinical rejection and cyclosporin (CsA) nephrotoxicity. In 29/29 acute rejection episodes the ABP level was elevated, beginning 1-7 days prior to treatment of rejection. Eighteen patients were treated for rejection with courses of OKT3 or antithymocyte globulin: 0/6 whose ABP level fell to normal during therapy had rerejection; 10/12 whose ABP level remained elevated had rerejection within 7 days of therapy completion. Of 15 patients treated with CsA, 7 had no rejection or drug toxicity; all 7 had normal ABP levels. The remaining 8 had CsA nephrotoxicity, all in association with elevated ABP levels that rapidly fell to normal with decreased CsA dose. An additional 7 patients with creatinine elevations more than 6 months posttransplant were studied: 5 had chronic vascular changes on biopsy, no response to increased immunosuppression, and normal ABP levels; 2 had a cellular infiltrate on biopsy, response to increased immunosuppression, and elevated ABP levels. We conclude that the urinary ABP assay provides information useful in the management of renal transplant patients with acute and chronic rejection and CsA toxicity.

Symptomatic cytomegalovirus disease in the cytomegalovirus antibody seropositive renal transplant recipient treated with OKT3.

A prospective study to investigate risk factors for CMV disease was conducted in 94 renal transplant recipients. CMV disease was defined as either unexplained fever for greater than 3 days with viremia or unexplained fever for greater than 3 days with isolation of CMV from the urine or throat wash and at least one of the following: leukopenia, elevated serum alanine aminotransferase, or biopsy-proved invasive tissue infection of the lung or gastrointestinal tract. Fifty-three patients received immunosuppressive regimens consisting of prednisone and cyclosporine, with or without azathioprine. The remaining 41 patients were treated with these agents plus OKT3 (21 received OKT3 to treat rejection, 20 received OKT3 prophylactically). Thirty-seven patients were at minimal risk of CMV disease (donor and recipient seronegative for CMV); 12 patients were at risk of primary disease (donor seropositive, recipient seronegative), and 45 were at risk of reactivation disease (recipient seropositive at the time of transplantation). The incidences of CMV disease in the 3 groups were 0%, 58%, and 36%, respectively. Although the incidence of CMV disease in patients at risk of primary disease was not influenced by the immunosuppressive regimen, immunosuppression had a profound effect on the occurrence of CMV disease in CMV-seropositive transplant recipients. The incidence of CMV disease in those receiving OKT3 was 59%; but only 21% in those who did not receive OKT3. OKT3 increased the risk of CMV disease five-fold (odds ratio 5.2 (95% confidence limits 1.4-17.5)). In the CMV-seropositive patient, OKT3 was also the most important predictor of CMV disease by multivariate analysis (P less than 0.002). A pilot study of preemptive therapy with ganciclovir (2.5 mg/kg daily during OKT3 therapy) in 17 patients decreased the incidence of CMV disease without appreciable toxicity.

Recent advances in the diagnosis and management of infection in the organ transplant recipient.

Infection remains a significant cause of morbidity and mortality in organ transplant patients, with significant infection being found in more than half of these individuals posttransplant. The most important principles of patient treatment are prevention, early diagnosis, and specific therapy. The nature of the antimicrobial therapy required both for infection prevention and treatment is closely linked to the immunosuppressive therapy being administered. A particular challenge in the transplant patient is that the antiinflammatory effects of antirejection therapy tend to obscure the manifestations of infection until relatively late in the disease process, thus putting particular emphasis on more aggressive diagnostic approaches-imaging procedures, biopsy, and new techniques for microbial detection (antigen and DNA detection). Antimicrobial therapy can be administered in three ways: therapeutically, prophylactically, and preemptively. Particularly given the propensity for adverse interactions between antimicrobial agents and cyclosporine and tacrolimus, there is a particular emphasis on prophylactic and preemptive use of antimicrobials.

The infectious disease problems of the diabetic renal transplant recipient.

Approximately 30% of patients with end stage renal disease who undergo transplantation develop renal failure as a result of their long-standing diabetes mellitus. Therefore, diabetics warrant special attention in considering the infectious disease problems associated with transplantation. The three categories that should be considered in infections affecting the diabetic renal transplant recipient are discussed in this article.

Urinary tract infection in the immunocompromised host. Lessons from kidney transplantation and the AIDS epidemic.

The occurrence of urinary tract infection and its clinical impact is determined, as with any infectious disease, by the interaction between the virulence of the infecting organism and the host defense mechanisms that can be mobilized. In the case of urinary tract infections, an anatomically and functionally intact kidney and urinary tract are the primary host defenses, with phagocytic function and immune mechanisms coming into play to limit the consequences of those infections. Of all the categories of immunocompromised hosts, the renal transplant patient is the one most susceptible to the direct and indirect consequences of urinary tract infections. In the first 3 months post transplant, the incidence of urinary tract infection is greater than 30%, and there is a relatively high rate of bacteremia and overt pyelonephritis of the allograft. After this time period, unless anatomic or functional derangement of the urinary tract is present, the direct clinical manifestations are far more benign. In addition to the direct effects of urinary tract infection on these patients, indirect effects are also important. These include the activation of CMV by TNF released as a consequence of a urinary tract infection and the initiation of allograft injury. Fortunately, low-dose trimethoprim-sulfamethoxazole or fluoroquinolones are safe and effective prophylactic strategies for preventing the direct and indirect consequences of urinary tract infections. Although the pathogenetic mechanisms are incompletely understood, data are emerging that AIDS patients have both an increased incidence and severity of urinary tract infection. The risk for urinary tract infections seem to be correlated with the degree of immune compromise and, perhaps, the amount of malnutrition and wasting that are present. The best strategies for preventing urosepsis in AIDS patients remain to be defined.

Ciprofloxacin in management of urinary tract infection.

Ciprofloxacin is a new quinolone derivative which is particularly well adapted for the treatment of bacterial urinary tract infection. Virtually all uropathogens are susceptible, and the development of resistance is uncommon. Its pharmacokinetic characteristics reveal that effective concentrations of the drug are easily achieved with twice a day oral therapy in the blood, urine, kidneys, and prostate--even in advanced renal failure. The drug is well tolerated, even with prolonged courses of therapy. It will be particularly useful in the treatment of antibiotic-resistant, complicated, and/or prostatic infection.

Amoxicillin and potassium clavulanate: an antibiotic combination. Mechanism of action, pharmacokinetics, antimicrobial spectrum, clinical efficacy and adverse effects.

The combination of amoxicillin and potassium clavulanate will soon be marketed in 2:1 and 4:1 fixed ratio dosage forms. In vitro and in vivo evidence suggests that clavulanic acid, a potent inhibitor of many bacterial beta-lactamase enzymes, will increase the spectrum of amoxicillin to include, at achievable serum concentrations, Haemophilus influenzae, H. ducreyi, Neisseria gonorrhoeae, Staphylococcus aureus and Branhamella catarralis and, at achievable urine levels, many beta-lactamase-producing strains of E. coli, Klebsiella, Proteus and Citrobacter. Both amoxicillin and clavulanic are well absorbed after oral administration, reach peak serum levels in 40-120 min and have similar half-lives of 45 to 90 min. This combination will be suitable for the treatment of complicated urinary tract infections, otitis media, sinusitis and respiratory tract infections. However, precise recommendations for its use will need to await further clinical trials that compare amoxicillin/clavulanate to alternative therapies.

Clinical management of urinary tract infection.

The clinical management of urinary tract infection has changed considerably over the last two decades due to the recognition of several important factors: All urinary tract infections are not the same; in particular, deep tissue infection of the kidney and/or prostate requires a very different form of clinical management than does superficial mucosal infection of the bladder. Consistent with these differences, it is now clear that conventional 7-14 day treatment courses are not ideal for most forms of urinary tract infections; deep tissue infection requires more intensive therapy and superficial mucosal infection needs less intensive therapy. In particular, single dose antimicrobial therapy has been a major advance in the management of the most common form of urinary tract infection--acute uncomplicated urinary tract infection of the adult female; such therapy is safe, effective, inexpensive, and the response provides useful clinical information. The recognition of the etiology of the acute urethral syndrome in most patients (true bacteriuria or Chlamydia trachomatis infection) had led to an effective therapeutic approach to this problem. A logical approach to the problem of recurrent urinary tract infection has emerged that is both cost-effective and clinically effective. Finally, a clearer picture of those populations that would benefit most from anatomical study of the urinary tract has been developed. With these advances, this most common of bacterial infections affecting man throughout his lifespan has become much easier to control.

Noninvasive renal diagnostic studies.

Traditional methods of noninvasively evaluating patients for renal injury do not accomplish the following tasks: reliably distinguish potentially treatable forms of acute renal failure from acute tubular necrosis; provide a sensitive indicator of early allograft rejection in renal transplant recipients, particularly those in the pediatric age group; provide an early warning of incipient drug-induced nephrotoxicity; or serve as an adequate screening test for renal injury due to exposure to occupational or environmental toxins, especially heavy metals. Because of this, considerable effort has been devoted to the development of assays to satisfy these needs. Three approaches include measurement in the urine of low-molecular-weight plasma proteins such as beta 2-microglobulin; a variety of kidney-derived enzymes, such as L-alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase; and specific renal antigens using immunologic detection. The first two of these have not proved to be adequately sensitive or specific, complicated by the frequent loss of activity associated with the physicochemical characteristics of the urine or the presence of pyuria. Despite this, useful information has been obtained. In particular, assays of beta 2-microglobulin urinary excretion and retinol binding protein appear to have clinical utility that should be pursued. Recent experience with a monoclonal antibody-based assay for a unique proximal tubular antigen, the adenosine deaminase binding protein, suggests that a battery of such assays, each directed against an antigen localized to a particular segment of the nephron, may be particularly useful.

Infection: the new problems.

Although great strides have been made in clinical transplantation, infection remains a major problem. Critical to the understanding of the infectious disease problems of the present and the foreseeable future is the recognition that the risk of infection is largely related to the interaction of two factors: the net state of immunosuppression present and the epidemiologic exposures the individual patient encounters. It is now apparent that different immunosuppressive agents with comparable antirejection effects will have differing effects on infectious processes. This is perhaps best illustrated by comparing the effects of cyclosporin and antithymocyte globulin on a murine model of cytomegalovirus infection. Cyclosporin appears to have little ability to reactivate latent virus but has profound virus-promoting effects once replicating virus is present. In contrast, antithymocyte globulin has potent reactivating effects but little influence on replicating infection. Thus, the infectious disease problems observed will be affected by the timing, nature, dose, and duration of the various components of the immunosuppressive program. As far as epidemiologic exposures are concerned, there is increasing emphasis on nosocomial hazards, particularly those encountered at such common sites within the hospital as operating rooms and radiology suites. Viral infections remain the most important single infectious disease problem among transplant patients for the foreseeable future. Although immunoglobulin prophylaxis and ganciclovir therapy appear to hold promise for limiting the effects of cytomegalovirus infection, hepatitis virus infection remains a major issue. In addition, it is likely that HIV infection, particularly the clinical management of asymptomatic carriers of the virus, will have an increasing impact on clinical transplantation over the next decade.

Opportunistic infections in renal allograft recipients.

The risk of opportunistic infection in the renal transplant patient is due to an interaction between two major factors: the epidemiologic exposures (particularly within the hospital environment) and the net state of immunosuppression. The net state of immunosuppression is determined by the nature, dose, and duration of the immunosuppressive therapy being administered; the presence or absence of granulocytopenia and technical factors that could compromise the primary mucocutaneous barriers to infection; such metabolic factors as uremia, hyperglycemia, and the state of nutrition; and, finally, the immunomodulating effects of such viruses as CMV, the hepatitis viruses, and HIV. The major types of opportunistic infection to which the renal transplant patient is susceptible are the following: the viruses of the herpes group and papovaviruses; bacteria such as L monocytogenes, N asteroides, and Legionella; such fungi as Candida, Aspergillus, C neoformans, and the Mucoraceae; and protozoans such as P carinii, S stercoralis, and T gondii.

The impact of infection on the outcome of transplantation.

The risk of infection in the transplant patient is determined by two factors: the net state of immunosuppression and the environmental exposures the patient encounters. Those infections that do occur in the transplant patient are strongly modulated by the type, intensity, duration, and sequence of immunosuppressive agents administered. A central role in the pathogenesis of all forms of infection in the transplant patient is played by the immunomodulating viruses, particularly cytomegalovirus. Prevention of infection is far better than treatment; when prevention fails and clinical disease develops, patient and allograft survival are directly related to the speed with which diagnosis is made and specific therapy instituted. In order to prevent disease, both antimicrobial prophylaxis and preemptive therapy are being increasingly employed, particularly to blunt the side effects of intensive antirejection therapy.