Management of urinary tract infections associated with nephrolithiasis.

Nephrolithiasis is a common clinical entity, and the incidence of renal stones appears to be increasing in the United States. Infection with uropathogens that produce urease can lead to the development of stones (infection stones), which serve as a continued source of recurrent infection and can lead to chronic kidney disease. Other than treating infection, medical management has little role in the treatment of infection stones; complete eradication of the stones with percutaneous nephrolithotomy or extracorporeal shock wave lithotripsy is required. Stones of metabolic origin can cause obstruction in the ureter and predispose to the development of urinary tract infection (UTI). Recognizing obstruction and initiating prompt drainage of the collecting system is important in the successful management of nephrolithiasis complicated by UTI. These patients are often at high risk of infection with an antimicrobial-resistant pathogen, so careful consideration of antimicrobial therapy is required, especially for patients who present with severe sepsis.

Surgery for infective endocarditis.

Infective endocarditis (IE) is estimated to have an incidence of five to seven cases per 100,000 person-years. Although not a common clinical entity, IE is associated with substantial morbidity and risk of mortality. IE, especially infections due to Staphylococcus aureus, are increasingly healthcare-associated infections. Despite significant advances in diagnosis and management, mortality from IE has changed little since the availability of penicillin; however, this lack of improvement in mortality is likely due to an increasing number of infections from more virulent and drug-resistant pathogens coupled with infections that occur in patients with other comorbidities and those associated with prosthetic valves. Surgery is an important part of therapy for many patients, but surprisingly, little evidence is available to help clinicians determine which patients will benefit most from surgical therapy for the management of IE.

The utility of deep soft-tissue cultures in diagnosing the causative agent of sternal osteomyelitis following median sternotomy.

BACKGROUND: The authors' goal was to determine whether the bacteria cultured from the mediastinal deep soft tissues matched those identified by the sternal bone cultures in cases of mediastinitis with clinically suspected sternal osteomyelitis, in hopes of eliminating the need for sternal bone biopsy. METHODS: The authors retrospectively reviewed the charts of 27 Detroit Medical Center patients who underwent median sternotomy and developed mediastinitis with clinical suspicion of osteomyelitis between 1996 and 2004. RESULTS: Although only 18 of 27 of the authors' patients had positive bone cultures, they demonstrate that in 94 percent (17 of 18) of these patients, the organisms cultured from the mediastinal deep soft-tissue cultures matched those cultured from the positive sternal bone cultures. CONCLUSIONS: With the results obtained from this study, the authors hope to promote a less-invasive means of investigating osteomyelitis in sternal wounds, to prevent the complications associated with obtaining a bone biopsy specimen in a contaminated soft-tissue setting. Instead, the authors suggest thoracic computed tomographic scanning as a noninvasive means of clinically demonstrating osteomyelitis of the sternum, and culture of the deep soft tissues of the mediastinum at the time of mediastinal debridement to determine the offending organism, if osteomyelitis is suggested by computed tomographic scan.

Ciprofloxacin for the management of urinary tract infection.

Urinary tract infections are common, especially among women. A number of agents are available for the treatment of urinary tract infections but emerging resistance to commonly used first-line therapies has impacted the selection of empirical therapy. Ciprofloxacin was the first member of the fluoroquinolone class of antibiotics to be widely available and is effective for the management of urinary tract infections. An extended-release formulation has recently become available that allows once-daily dosing, which may improve patient adherence and convenience. Clinical trials have demonstrated that the extended-release formulation is as effective as the standard formulation in the management of acute uncomplicated cystitis, complicated urinary tract infections and acute uncomplicated pyelonephritis. The pharmacokinetics of the extended-release formulation may offer potential advantages in terms of microbial eradication and clinical response; however, this has yet to be demonstrated in clinical trials. In the USA and western Europe, overall rates of quinolone resistance among common uropathogens have remained low; however, reports of increasing resistance from certain geographical areas are of great concern. Risk factors for resistance are currently poorly defined.

Antimicrobial Selection in the Treatment of Pyelonephritis.

Pyelonephritis is a common clinical entity, although accurate data regarding the true prevalence of this infection are lacking. Acute pyelonephritis is associated with significant morbidity and even mortality. There are very few randomized controlled clinical trials that have addressed the optimal management strategies and antimicrobial therapy for this infection. Increasing resistance among uropathogens, especially Escherichia coli, has impacted recommendations for empiric antimicrobial therapy, and fluoroquinolones have emerged as the empiric therapy of choice for individuals managed as outpatients; more options are available for empiric parenteral therapy for those who require hospitalization. Further study of the epidemiology of antimicrobial resistance among uropathogens and of alternative agents for the management of pyelonephritis is urgently needed.

Adherence to guidelines for community-acquired pneumonia: does it decrease cost of care?

Community-acquired pneumonia (CAP) is a common diagnosis and care of CAP is responsible for significant healthcare expenditures, the majority of which are for patients who require hospitalisation. Studies have shown that significant variation exists among institutions with respect to antibacterial costs and length of stay (LOS) for CAP. These variations do not appear to be associated with significant differences in patient outcomes. This information has stimulated the development of practice guidelines and critical pathways to optimise the care of patients with CAP. The central focus of guidelines is recommendations for antibacterial therapy; critical pathways include recommendations for therapy, but focus on the process of care for patients with CAP. Guidelines and critical pathways are time consuming to develop and their implementation requires significant institutional resources. Therefore, it is essential that they are shown to be effective, and there has been significant interest in determining if guidelines and pathways can improve the cost effectiveness of care. In the past several years, a number of studies have evaluated the impact of treatment consistent with guidelines on outcomes for patients with CAP. These studies have shown that antibacterial therapy that is consistent with guidelines can reduce LOS, decrease costs, and several have shown a favourable impact on mortality. The majority of these studies have been retrospective reviews. One multicenter prospective, randomised trial of a critical pathway for CAP revealed significant reductions in the hospital admission of patients, LOS and cost of care. Other studies of processes of care have been mainly 'before and after' interventions; many have shown reductions in LOS and costs. Based on the available data, it is reasonable to expect that adherence to guidelines and critical pathways can reduce the cost of care for CAP; however, randomised controlled trials that include a formal cost-effectiveness analysis are needed. Even if the data to support the use of guidelines and pathways are robust, those who develop and implement them need to anticipate and understand barriers to physician adherence.

Impact of Changing Patterns of Antimicrobial Resistance in Uropathogens: Emerging Treatment and Strategies.

Urinary tract infection (UTI) is common, especially in women, and the microbiology of UTI is predictable. Over the past decade, numerous reports have documented increasing resistance among uropathogens to first-line agents for the treatment of UTI, especially trimethoprim/sulfamethoxazole (TMP/SMX). It is recommended that TMP/SMX should not be administered as empiric therapy for UTI in communities where resistance rates exceed 20%. However, reliable data regarding the true prevalence of resistance in a community are often lacking. Preliminary work has suggested that recent antimicrobial use is an important risk factor for infection with a TMP/SMX-resistant isolate. A better understanding of the epidemiology of resistance is needed to aid therapeutic decisions and devise interventions to reduce or slow emerging resistance.

Acute pyelonephritis in US hospitals in 1997: hospitalization and in-hospital mortality.

PURPOSE: To describe the 1997 incidence of hospitalization for acute pyelonephritis in the US and the risk factors for in-hospital mortality associated with acute pyelonephritis. METHODS: Cases were defined as those with ICD9-CM codes corresponding to acute pyelonephritis in the 1997 Health Care Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS). Frequencies and calculations were weighted to produce either national or state estimates. Hospitalization rates were calculated using 1997 US Census Bureau population projections for the denominator. RESULTS: Females were almost five times as likely as males to be hospitalized for acute pyelonephritis (11.7/10,000 vs. 2.4/10,000), but males had higher mortality rates (16.5/1000 vs. 7.3/1000); 30% greater after adjustment. Hospitalization and in-hospital mortality rates increased with age, but not with diabetes. Mortality rates increased with number of procedures, diagnoses and having a major diagnostic category other than disorders of the kidney and urinary tract. Persons living in zip codes with lower median incomes were also at higher risk of mortality. There was little variation in mortality by hospital size, ownership, location or teaching status. CONCLUSION: In hospital mortality for pyelonephritis was associated with patient rather than hospital characteristics suggesting uniform application of standard care across hospitals and populations.

Urinary Tract Infections in Renal Transplant Recipients.

Infection of the urinary tract is the most common infectious complication of renal transplantation. The microbiology of post-transplant urinary tract infections is similar to what is seen in the general population, although transplant patients may develop infections due to unusual or opportunistic pathogens. The optimal management of urinary tract infections in renal transplant recipients is poorly studied, but recommendations for treatment are available. Antibiotic prophylaxis can reduce the risk of bacterial infection of the urinary tract post-transplant but is not used in all transplant centers. The influence of urinary tract infection on graft survival requires further study.

Infective endocarditis in the injection drug user.

Although infective endocarditis is certainly not the most common infection seen in injecting drug users, it is the infection that clinicians most commonly think of when they consider infectious complications of injected drug use. The microbiology of infective endocarditis in injection drug users has remained relatively stable over the last several decades. Tricuspid valve endocarditis has been associated most frequently with injection drug use, but recent reports have suggested that involvement of left-sided valves is seen more often now than in the past. The use of transesophageal echocardiography has greatly advanced the ability to diagnose infective endocarditis and the cardiac complications of valvular infection.

Skin and Soft Tissue Infections in Injection Drug Users.

Skin and soft tissue infections (SSTIs) are common among injection drug users (IDUs). Subcutaneous and intramuscular injection ("skin-popping") and the injection of "speedballs" (a mixture of heroin and cocaine) are important risk factors for SSTIs in this patient population. Female IDUs appear to be at greater risk of SSTIs than male IDUs, probably because of more difficult venous access. There are conflicting data regarding the impact of HIV and human T-cell lymphotrophic virus II infection on the risk of SSTIs in IDUs; however, an expanding body of evidence suggests that immunosuppressive effects of the drugs themselves may play a role. Most information regarding the microbiology of SSTIs in IDUs comes from data on skin and subcutaneous abscesses, where Staphylococcus aureus and organisms that originate from the oral flora predominate. Clonal outbreaks and uncommon infections including tetanus, wound botulism, and a sepsis/myonecrosis syndrome due to Clostridium species have been recently reported in IDUs.

Prevalence and predictors of trimethoprim-sulfamethoxazole resistance among uropathogenic Escherichia coli isolates in Michigan.

Resistance among uropathogenic Escherichia coli to trimethoprim-sulfamethoxazole (TMP-SMX) has increased. Risk factors for resistance and the impact on clinical failure have been poorly described. We performed a retrospective cohort study of women with acute uncomplicated cystitis seen at a university health center and at primary care clinics in southeastern Michigan from 1992 to 1999. The prevalence of TMP-SMX resistance increased from 8.1% to 15.8% (P=.01). Women who had taken TMP-SMX recently were >16 times as likely as women who had not taken antibiotics recently to be infected with an isolate resistant to this agent; those who had taken any other antibiotic were more than twice as likely to be infected with a resistant isolate. Women infected with a TMP-SMX-resistant isolate who were treated with TMP-SMX were >17 times as likely to have treatment failure. Recent antibiotic use is a risk factor for infection with a TMP-SMX-resistant isolate; patients who are infected with a TMP-SMX-resistant isolate and who are treated with this agent are at a higher risk for clinical failure.

Diagnostic Investigation of Pyelonephritis.

Urinary tract infections are common, especially among women, and cause significant morbidity. While prognosis is probably more dependent on whether or not an episode of urinary tract infection is complicated (ie, associated with functional, metabolic, or anatomic abnormalities of the urinary tract) or uncomplicated, anatomic localization of infection has important implications for therapy. Pyelonephritis is difficult to diagnose with a high degree of accuracy based on clinical findings alone. Radiologic imaging plays an important role in the diagnosis and management of selected patients. Noninvasive and inexpensive methods to allow accurate localization of infection are needed.