Community-acquired bacteremic urinary tract infection: epidemiology and outcome

Exploring Inflammatory Status in Febrile Seizures Associated with Urinary Tract Infections: A Two-Step Cluster Approach

BACKGROUND

Urinary tract infections (UTIs) are considered common facilitating factors, along with other infections, in triggering febrile seizures (FS). The main purpose of our study was to identify specific inflammatory patterns of UTI cases from other infections in a specific cluster, using a combination of inflammatory biomarkers to differentiate UTIs from other bacterial diseases triggering FS.

METHOD

This prospective study included a number of 136 patients with 197 distinct FS events, from patients hospitalized in the Pediatric Clinical Hospital Sibiu, among which 10.2% were diagnosed with UTIs.

RESULTS

In one-third of the patients with UTIs (20 cases), the symptoms were limited to fever and FS. Using two-step cluster analysis, a distinct UTI inflammatory pattern has emerged: highest platelet values (PLT), median value 331 × 103/mm3 and intermediate C-reactive protein (CRP), median value 15 mg/dL, platelet distribution width (PDW), median value 9.65%, platelet-large cell ratio (P-LCR), median value 14.45%, mean platelet volume (MPV), median value 8.60 fL and neutrophil-to-lymphocyte values (NLR), median value 3.64. Furthermore, higher PDW (median value 12.25%), P-LCR (median value 28.55%), MPV (median value 10.40 fL), CRP (median value 74.00 mg/dL) and NLR values (median value 4.11) were associated mainly (85.7%) with bacterial lower respiratory infections. UTIs were highly unlikely in these patients with significantly increased CRP values and normal values of platelet indices.

CONCLUSIONS

Considering the nonspecific clinical picture of UTIs at an early age, to optimize the management of FS, a fast diagnosis of UTI is mandatory. The analysis of the inflammatory biomarker clusters (rather than individual parameters) correlated with urine leukocyte and nitrite stick evaluation for specific age groups could help in identifying even oligosymptomatic UTIs patients. The study limitation (20 UTI cases) recommends future multicentric trials on larger datasets to validate the model.

The management of urinary infections: what have we learned in the past decade?

User-friendly, cost-effective practices to manage urinary infection should become routine. The vast majority of inflections are relatively easy to treat and many of these can be prevented with appropriate interventions. Additional research is urgently needed to compare various clinical strategies and determine which is most acceptable to patients at a reasonable cost with satisfactory health outcomes.

Bacteremia complicating gram-negative urinary tract infections: a population-based study

BACKGROUND

Urinary tract infection (UTI) is common and bacteremia complicating this infection is frequently seen. There has been limited data published that characterize bacteremic UTI in a population-based setting over an extended period. We therefore examined the incidence rate, microbiology, outcome, and in vitro antimicrobial resistance trends of bacteremic UTI due to gram-negative bacilli in Olmsted County, Minnesota, from 1/1/1998 to 12/31/2007.

METHODS

We used Kaplan-Meier method to estimate mortality rates, Cox proportional hazard regression to determine risk factors for mortality, and logistic regression to examine temporal changes in antimicrobial resistance rates.

RESULTS

We identified 542 episodes of bacteremic gram-negative UTI among Olmsted County residents during the study period. The median age of patients was 71 years and 65.1% were females. The age-adjusted incidence rate per 100,000 person-years was 55.3 (95% confidence interval [CI]: 49.5-61.2) in females and 44.6 (95% CI: 38.1-51.1) in males. Escherichia coli was the most common pathogen (74.9%). The 28-day and 1-year all-cause mortality rates were 4.9% (95% CI: 3.0-6.8) and 15.6% (95% CI: 12.4-18.8), respectively. Older age was associated with higher mortality; community-acquired infection acquisition and E. coli UTI were both independently associated with lower mortality. During the study period, resistance rates increased linearly from 10% to 24% for trimethoprim-sulfamethoxazole and from 1% to 8% for ciprofloxacin.

CONCLUSIONS

To our knowledge, this is the first population-based study of bacteremic gram-negative UTI. The linear trend of increasing antimicrobial resistance among gram-negative isolates should be considered when empiric therapy is selected.

The clinical impact of bacteremia in complicated acute pyelonephritis

BACKGROUND

Bacteremia has been considered as a surrogate marker of severe infection in several infectious diseases. However, it remains uncertain whether the presence of bacteremia correlates with severe infection in patients with complicated acute pyelonephritis (APN).

METHODS

We performed a retrospective study to investigate the relationship between the presence of bacteremia and disease severity in complicated APN. To do this, we reviewed medical records from 128 patients diagnosed with complicated APN admitted to Kaohsiung Veterans General Hospital, Taiwan between January, 2003 and December, 2003. In our analysis, we compared clinical presentation, treatment response, and outcome in patients with and without bacteremia.

RESULTS

Fifty-four of 128 patients (42%) were bacteremic. This group of patients presented more frequently with severe sepsis or septic shock (P < 0.001), compared with nonbacteremic patients. Other factors that correlated with the presence of bacteremia were older age, diabetes mellitus, more band forms in neutrophil cell counts, impaired renal function, and a lower level of serum albumin. Using a multivariate logistic regression analysis, we show that lower levels of serum albumin (odds ratio, 0.18; 95% CI, 0.05-0.65; P = 0.008) and presence of severe sepsis (odds ratio, 4.76; 95% CI, 1.43-15.84; P = 0.011) were independent factors associated with bacteremia. Following treatment, the bacteremic group took a longer time to become defervescent than the nonbacteremic group (5.1 +/- 2.3 vs. 4.2 +/- 1.6 days, P = 0.023). Also, the bacteremic group had a greater mean duration of intravenous antibiotics administration and longer hospital stays (P < 0.001). Multiple logistic regression analysis shows that non-Escherichia coli bacteremia, presence of urolithiasis or hydronephrosis, shorter duration of antibiotics administration, and being male were significantly associated with recurrence of urinary tract infection within 6 months.

CONCLUSION

Bacteremia in cases of complicated APN indicates a severe disease, which is more likely to recur in patients with non-E coli bacteremia. Our study showed that bacteremia is indeed a useful clinical indicator of severe disease and, if found, should influence patient management. Therefore, we recommend that blood culture samples should be taken in all patients with complicated APN.

Community-acquired urinary tract infection in adults: a hospital viewpoint

The clinical and epidemiologic spectrum of 175 cases of community-acquired urinary tract infection (UTI) were evaluated at a university hospital. Patients were grouped in five different categories of which complicated UTI was the most common (39%). Bacteraemia was detected in eight patients (18%) of this group and in five (12%) with acute uncomplicated pyelonephritis. A single organism was isolated in 166 cases (95%). The rate of Escherichia coli bacteriuria ranged from 60% (asymptomatic bacteriuria) to 94% (uncomplicated cystitis). Of the 184 isolates, 92% were susceptible to ciprofloxacin and significantly high rates of resistance were found for ampicillin, cefazolin, cefuroxime, and co-trimoxazole. Isolates causing uncomplicated UTI had significantly high rates of resistance to ampicillin, amoxycillin-clavulanate and co-trimoxazole and those causing complicated UTI, had significantly high rates of resistance to most oral antibiotics tested, except quinolones and nitrofurantoine. Community-acquired UTI requiring hospital evaluation occurs in a complex group of patients, and current patterns of antibiotic resistance make it difficult to suggest empiric oral treatments in this setting.

Urinary tract infection. Current management strategies

Urinary tract infection is one of the most common infectious diseases in the United States. The term encompasses a wide range of infections, from mild bacteriuria to more severe, complicated upper tract infection. Bacterial virulence factors, host defense mechanisms, and various predisposing factors affect the course and severity of disease. Recent advances in treatment have focused on improved management strategies for specific types of infection (eg, re-current cystitis in women, catheter-related infection). In some cases, the causative organisms are highly predictable and empirical therapy without pretreatment culture is recommended. Other infections (eg, pyelonephritis) require at least 10 days of antimicrobial therapy, and if complications are present, hospitalization may be warranted.

Polymicrobial and monomicrobial bacteraemic urinary tract infection

Polymicrobial blood or urine cultures in bacteraemic urinary tract infection (UTI) are relatively common. There is, however, very little information available on the clinical and bacteriological features that distinguishes between monomicrobial and polymicrobial urosepsis. During 1980-84, 68 of 198 episodes (34%) of urosepsis with at least one identical organism in blood and urine, had multiple growth in either one or the other. Comparison between monomicrobial and polymicrobial infectious episodes showed that the latter were more often hospital-acquired and more frequently associated with urinary catheters. Pseudomonas aeruginosa was more often associated with polymicrobial than with monomicrobial infections, whereas Escherichia coli was more common in monomicrobial infections. Mortality was higher in polymicrobial infections, and was further increased if multiple organisms grew from blood rather than from urine. Thus, there are clinical, microbiological and prognostic characteristics that distinguish polymicrobial from monomicrobial bacteraemic UTIs.

Nosocomial bacteremia in a medical-surgical intensive care unit: epidemiologic characteristics and factors influencing mortality in 111 episodes

OBJECTIVE

To analyze the epidemiology and factors influencing mortality of ICU-acquired bacteremia.

DESIGN

Prospective clinical study.

SETTING

A medical-surgical ICU in an university hospital.

PATIENTS

We recorded variables from 111 consecutive ICU-acquired episodes for a 3-year period.

RESULTS

The attack rate was 1.9 episodes per 100 patient-days. The commonest isolates were coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Intravascular catheters were the most frequent source of infection. Overall mortality was 31.5%, and 65.7% of all deaths were directly attributable to infection. Bacteremia from intra-abdominal, lower respiratory tract or unknown origin were associated with a poor prognosis. A logistic regression analysis defined intraabdominal origin (p = 0.01, OR = 15.7) and presence of shock (p = 0.04, OR = 3.3) as independently influencing the risk of death. No significant differences were found for the remaining variables studied.

CONCLUSIONS

Epidemiology and etiology of ICU-acquired bacteremia does not differ seriously in respect to nosocomial bacteremia among unselected populations, although it is associated with a greater incidence and overall mortality. Presence of shock is the most important modificable variable affecting the outcome.

Bacteremic and non-bacteremic febrile urinary tract infection--a review of 168 hospital-treated patients

Patients with febrile urinary tract infections with (80 patients) or without (88 patients) positive blood cultures were reviewed. Eighty-nine percent of the infections were community acquired. The bacteremic patients were older, Escherichia coli was the most commonly found organism in both groups. The most important finding in this study was increased frequency of resistance to three common urinary tract antibiotics (ampicillin, cephalothin and trimethoprim-sulfamethoxazole) in E. coli from patients with non-bacteremic compared with bacteremic infections. Complications occurred in 28 bacteremic and in three non-bacteremic patients. Six patients died, all with bacteremia. The significantly higher temperature at admittance among patients with gram-negative versus gram-positive bacteremic infection possibly reflects an effect by endotoxin.

Bacterial etiologic agents in the pathogenesis of urinary tract infection

Most of the information available concerning virulence factors of uropathogens is based on studies of Escherichia coli, the commonest cause of urinary tract infections. Earlier studies revealed several phenotypic Escherichia coli virulence factors that influenced both the anatomic level and severity of urinary tract infection. Virulence factors included O antigen serotype, presence and quantity of K capsular polysaccharide, adherence to uroepithelial cells, resistance to serum bactericidal activity, hemolysin, and aerobactin production. The introduction of DNA hybridization methodology has provided a valuable tool for reevaluation of the epidemiology of Escherichia coli infection as well as an alternative to the conventional phenotypic approach for studying the genotypic basis for virulence.

Clinical implications of positive blood cultures

Positive blood cultures can be classified according to their veracity (true-positive or false-positive culture), clinical severity (inconsequential or life threatening), place of origin (community acquired or nosocomial), source (primary or secondary), duration (transient, intermittent, or continuous), pattern of occurrence (single episode, persistent, or recurrent), or intensity (high or low grade). In general, however, positive blood cultures identify a patient population at high risk of death. In my studies, patients with positive blood cultures were 12 times more likely to die during hospitalization than patients without positive blood cultures. Many bacteremias and fungemias occur in complicated clinical settings, and it appears that only about one-half of the deaths among affected patients are due directly to infection. Hence, it is appropriate to speak of "crude mortality" and "attributable mortality." Among hospitalized patients, recent trends include rising incidences of Staphylococcus aureus and coagulase-negative staphylococcal and enterococcal bacteremias and a dramatic increase in the incidence of fungemias. The diagnostic and therapeutic implications of blood cultures positive for specific microorganisms continue to evolve and are the subject of a large and growing medical literature.

Hospital-acquired bacteremic urinary tract infection: epidemiology and outcome

Analysis of 221 episodes of hospital-acquired bacteremic urinary tract infection in 4 hospitals of 1 metropolitan area from 1977 to 1981 revealed an over-all mortality rate of 30.8 per cent. The mortality rate attributed specifically to bacteremic urinary tract infection was 12.7 per cent. Of the 28 patients whose deaths were attributed directly to hospital-acquired bacteremic urinary tract infection 19 were on medical services and all had focal or diffuse central nervous system disease, malignancy, alcoholic liver disease or cirrhosis, advanced arteriosclerosis with renal failure and/or diabetes mellitus with obliterative peripheral vascular disease. Extrapolation of these data suggests that 3,520 deaths in the United States each year are directly caused by hospital-acquired bacteremic urinary tract infection but that these deaths may be limited virtually to high risk patients with poor prognoses from underlying diseases.