Usefulness of blood cultures in pyelonephritis

A biomarker for bacteremia in pregnant women with acute pyelonephritis: soluble suppressor of tumorigenicity 2 or sST2

Objective: Sepsis is a leading cause of maternal death, and its diagnosis during the golden hour is critical to improve survival. Acute pyelonephritis in pregnancy is a risk factor for obstetrical and medical complications, and it is a major cause of sepsis, as bacteremia complicates 15-20% of pyelonephritis episodes in pregnancy. The diagnosis of bacteremia currently relies on blood cultures, whereas a rapid test could allow timely management and improved outcomes. Soluble suppression of tumorigenicity 2 (sST2) was previously proposed as a biomarker for sepsis in non-pregnant adults and children. This study was designed to determine whether maternal plasma concentrations of sST2 in pregnant patients with pyelonephritis can help to identify those at risk for bacteremia.Study design: This cross-sectional study included women with normal pregnancy (n = 131) and pregnant women with acute pyelonephritis (n = 36). Acute pyelonephritis was diagnosed based on a combination of clinical findings and a positive urine culture. Patients were further classified according to the results of blood cultures into those with and without bacteremia. Plasma concentrations of sST2 were determined by a sensitive immunoassay. Non-parametric statistics were used for analysis.Results: The maternal plasma sST2 concentration increased with gestational age in normal pregnancies. Pregnant patients with acute pyelonephritis had a higher median (interquartile range) plasma sST2 concentration than those with a normal pregnancy [85 (47-239) ng/mL vs. 31 (14-52) ng/mL, p < .001]. Among patients with pyelonephritis, those with a positive blood culture had a median plasma concentration of sST2 higher than that of patients with a negative blood culture [258 (IQR: 75-305) ng/mL vs. 83 (IQR: 46-153) ng/mL; p = .03]. An elevated plasma concentration of sST2 ≥ 215 ng/mL had a sensitivity of 73% and a specificity of 95% (area under the receiver operating characteristic curve, 0.74; p = .003) with a positive likelihood ratio of 13.8 and a negative likelihood ratio of 0.3 for the identification of patients who had a positive blood culture.Conclusion: sST2 is a candidate biomarker to identify bacteremia in pregnant women with pyelonephritis. Rapid identification of these patients may optimize patient care.

Clinical and computed tomography factors associated with sepsis in women with clinically uncomplicated pyelonephritis

OBJECTIVE

Sepsis is major determinants of prognosis in acute pyelonephritis (APN). This study aimed to assess factors associated with the development of sepsis among patients with clinically uncomplicated APN.

SUBJECTS AND METHODS

We examined 463 patients presenting to our hospital without complications. We assessed clinical factors including demographic and laboratory features. Renal and extrarenal features on computed tomography (CT) were also analyzed. Risk factors of sepsis are assessed.

RESULTS

The study included 361 patients without (78.0%) and 102 patients with sepsis (22.0%). Crude and attributable mortality rates were 3.9% and 2.0% versus 1.4% and 0.6%, respectively, among patients with and without sepsis. Clinical risk factors for sepsis were age >65 years (odds ratio [OR] 1.79, P = 0.02), absence of flank pain (OR 1.59, P = 0.04), absence of costovertebral tenderness (OR 1.89, P = 0.03), diabetes mellitus (OR 2.25, P = 0.02), bacteremia (OR 2.8, P = 0.01), C-reactive protein level >100 mg/L (OR 1.42, P = 0.02), and lack of previous APN history (OR 1.76, P = 0.04). APN grade IV (OR 3.16, P = 0.01), high grade hydronephrosis (OR 1.50, P = 0.03), diffuse peritoneal thickening (OR 4.12, P = 0.01), and acute interstitial pulmonary edema (OR 3.73, P = 0.01) were the CT features predictive of septic shock.

CONCLUSIONS

Although uncomplicated APN was largely non-fatal, several clinical and CT features could lead to sepsis. Our findings may be useful for predicting sepsis risk and deciding whether intravenous antibiotic treatment and intensive management should be initiated for uncomplicated APN.

The Shapiro-Procalcitonin algorithm (SPA) as a decision tool for blood culture sampling: validation in a prospective cohort study

PURPOSE

Blood cultures (BC) are the gold standard for bacteremia detection despite a relatively low diagnostic yield and high costs. A retrospective study reported high predictive values for BC positivity when combining the clinical Shapiro score with procalcitonin (PCT).

METHODS

Single-center, prospective cohort study between 01/2016 and 02/2017 to validate SPA algorithm, including a modified Shapiro score ≥ 3 points (S) PLUS admission PCT > 0.25 µg/l (P), or presence of overruling safety criteria (A) in patients with systemic inflammatory response syndrome. The diagnostic yield of SPA compared to non-standardized clinical judgment in predicting BC positivity was calculated and results presented as odds ratios (OR) with 95% confidence intervals.

RESULTS

Of 1438 patients with BC sampling, 215 (15%) had positive BC which increased to 31% (173/555) in patients fulfilling SP criteria (OR for BC positivity 9.07 [6.34-12.97]). When adding 194 patients with overruling safety criteria (i.e., SPA), OR increased to 11.12 (6.99-17.69), although BC positivity slightly decreased to 26%. With an area under the receiver operating curve of 0.742, SPA indicated better diagnostic performance than its individual components. Positive BC in 689 patients not fulfilling SPA (sampling according to non-standardized clinical judgment) were rare (3%; OR for BC positivity 0.09 [0.06-0.14]). Eight out of 21 missed pathogens were still identified by sampling the primary infection focus.

CONCLUSIONS

This study validates the high predictive value of SPA for bacteremia, increasing true BC positivity from 15 to 26%. Restricting BC sampling to SPA would have reduced BC sampling by 48%, while still detecting 194/215 organisms (90%), which makes SPA a valuable diagnostic stewardship tool.

Management of acute pyelonephritis in the emergency department observation unit

INTRODUCTION

This study aimed to assess the effectiveness of the emergency department observation unit (EDOU) for patients with acute pyelonephritis in a Singapore tertiary academic medical centre.

METHODS

We reviewed the clinical records of consecutive patients who presented with pyelonephritis between 1 July 2012 and 31 October 2014 to collect information on demographics, symptoms, signs, laboratory and radiological results, treatment, and clinical outcomes.

RESULTS

Of 459 emergency department (ED) patients who were identified as having pyelonephritis, 164 (35.7%) were managed in the EDOU. Successful management in the EDOU was achieved in 100 (61.0%) patients. Escherichia coli was the predominant (64.6%) micro-organism in urine cultures and was positive in 106 patients. Patients diagnosed with acute pyelonephritis who were successfully managed in the EDOU had a lower incidence of nausea (32.0% vs. 60.9%, p < 0.001) and vomiting (15.0% vs. 50.0%, p < 0.001) compared to those who were not successful.

CONCLUSION

EDOU is useful for both observation and treatment of patients with acute pyelonephritis. Urine cultures are sufficient for the identification of the culprit micro-organism. Patients who present with prominent symptoms of vomiting should have routine administration of antiemetics, while consideration for second-line antiemetics is recommended for those with persistent symptoms.

The Emergency Department Diagnosis and Management of Urinary Tract Infection

Urinary tract infection (UTI) is a common infection seen in the emergency department. The spectrum of UTI includes simple versus complicated infection and lower versus upper UTI. No one history or examination finding is definitive for diagnosis. Testing often includes urinalysis and/or urine dipstick, and several pitfalls may occur in interpretation. Urine cultures should be obtained in complicated or upper UTIs but not simple and lower tract UTIs, unless a patient is pregnant. Imaging often is not required. Most patients with simple cystitis and pyelonephritis are treated as outpatients. A variety of potentially dangerous conditions may mimic UTI and pyelonephritis.

The Use of Routine Blood Cultures in Pediatric Appendicitis

OBJECTIVES

To determine the proportion of true-positive blood culture results in children presenting to the ED with suspected appendicitis. To describe the current practice of obtaining blood cultures in children with suspected appendicitis.

METHODS

We performed a 2-year retrospective health record review of all children aged 2 through 17 years investigated for suspected appendicitis at a tertiary Pediatric Emergency Department. Subjects were identified by searching (a) institutional records for ICD-10-CA coding, (b) diagnostic imaging records of ultrasounds for appendicitis, and (c) surgical database records for nonincidental appendectomies. Abstracted demographic and clinical data were matched to regional laboratory services data to describe the performance and result of blood cultures.

RESULTS

Overall, 1315 children investigated for appendicitis were reviewed. Seven hundred fifty (57.0%) were girls, the average age was 11.7 years (SD, 4.0). Blood cultures were obtained in 288 (21.9%) of 1315 patients. Of the 11 (3.8%) cultures that were positive, only 1 (0.35%) was a true positive. Young age, high triage acuity, and presence of fever were associated with the acquisition of cultures (P < 0.001 for all). The proportion of children undergoing appendectomy and the negative appendectomy rate was similar between those with and without blood culture (P = 0.10 and P = 0.96, respectively).

CONCLUSIONS

True-positive blood cultures are very rare in children presenting to the ED with suspected appendicitis. Given the potential for false-positive cultures and the social/economic implications of initial testing/retesting of false positives, the use of routine blood cultures for children with suspected appendicitis is not supported.

Care of Infectious Conditions in an Observation Unit

Infectious conditions such as skin and soft tissue infections (SSTIs), Urogenital infections and peritonsillar abscesses frequently require care beyond emergency stabilization and are well-suited for short term care in an observation unit. SSTIs are a growing problem, partly due to emergence of strains of methicillin-resistant S. aureus (MRSA). Antibiotic choice is guided by the presence of purulence and site of infection. Purulent cellulitis is much more likely to be associated with MRSA. Radiographic imaging should be considered to aid in management in patients who are immunosuppressed, have persistent symptoms despite antibiotic therapy, recurrent infections, sepsis or diabetes.

Low yield of blood and wound cultures in patients with skin and soft-tissue infections

BACKGROUND

Current guidelines recommend blood cultures in skin and soft-tissue infection (SSTI) patients only with signs of systemic toxicity and wound cultures for severe purulent infections. Our objectives were to determine: 1) blood and wound culture yields in patients admitted with SSTIs; 2) whether injection drug users (IDUs) and febrile patients had higher blood culture yields; and 3) whether blood and wound cultures grew organisms sensitive to typical SSTI empiric antibiotics.

METHODS

We prospectively enrolled adult patients admitted from the ED with SSTIs at an urban hospital. We recorded patient characteristics, including IDU, comorbidities and temperatures, and followed admitted patients throughout their hospital course.

RESULTS

Of 734 SSTI patients enrolled, 246 (33.5%) were admitted. Of 86 (35.0%) patients who had blood cultures, six had positive cultures (yield=7.0%; 95% confidence intervals [CIs] 3.2-14.4); 4 were methicillin sensitive Staphylococcus aureus (MSSA) and 2 were methicillin resistant (MRSA). Of 29 febrile patients, 1 had a positive culture (yield=3.5%; 95% CI 0.6-17.2). Of 101 admitted IDU patients, 46 (46%) received blood cultures, and 4 had positive cultures (yield=8.7%; 95% CI 3.4-20.3). Of 89 patients with purulent wounds, 44 (49.4%) patients had ED wound cultures. Thirteen had positive cultures (yield=29.6%; 95% CI 18.2-44.2%). Most were MRSA, MSSA, and group A Streptococcus species - all sensitive to Vancomycin.

CONCLUSIONS

Febrile and IDU patients had low yields of blood cultures similar to yields in non-IDU and afebrile patients. All blood and wound culture species were adequately covered by currently recommended empiric antibiotic regimens.

Usefulness of Blood Cultures and Radiologic Imaging Studies in the Management of Patients with Community-Acquired Acute Pyelonephritis

Background

The objective of this study was to examine the usefulness of blood cultures and radiologic imaging studies for developing therapeutic strategies in community-acquired acute pyelonephritis (CA-APN) patients.

Materials and Methods

We prospectively collected the clinical data of CA-APN patients who visited 11 hospitals from March 2010 to February 2011.

Results

Positive urine and blood cultures were obtained in 69.3% (568/820) and 42.7% (277/648), respectively, of a total of 827 CA-APN patients. Blood culture identified the urinary pathogen in 60 of 645 (9.3%) patients for whom both urine and blood cultures were performed; the organisms isolated from urine were inconsistent with those from blood in 11 and only blood cultures were positive in 49 patients. Final clinical failure was more common in the bacteremic patients than the non-bacteremic ones (8.0% vs. 2.7%, P = 0.003), as was hospital mortality (3.6% vs. 0.3%, P = 0.003). Likewise, durations of hospitalization and fever were significantly longer. Bacteremia was independent risk factor for mortality (OR 9.290, 1.145-75.392, P = 0.037). With regard to radiologic studies, the detection rate of APN was 84.4% (445/527) by abdominal computed tomography and 40% (72/180) by abdominal ultrasonography. Eighty-one of 683 patients (11.9%) were found to have renal abscess, perinephric abscess, urolithiasis, hydronephorosis/hydroureter or emphysematous cystitis, which could potentially impact on clinical management. Patients with Pitt score ≥ 1, flank pain or azotemia were significantly more likely to have such structural abnormalities.

Conclusion

Blood cultures are clinically useful for diagnosis of CA-APN, and bacteremia is predictive factor for hospital mortality. Early radiologic imaging studies should be considered for CA-APN patients with Pitt scores ≥1, flank pain or azotemia.

For reliable urine cultures in the detection of complicated urinary tract infection, do we use urine specimens obtained with urethral catheter or a nephrostomy tube?

OBJECTIVE

The aim of this study was to compare the results of urine cultures obtained either from urethral, and percutaneous nephrostomy (PCN) catheters.

MATERIALS AND METHODS

This study included 328 consecutive patients that underwent PCN at our institution with complicated urinary tract infections (UTIs) between July 2010 and April 2015. Results of urine cultures obtained from the urethral and nephrostomy catheters were compared.

RESULTS

This study included 152 male and 176 female patients. Mean age of the patients was 46.2±24.3 years. The main indications were obstructive uropathy due to urolithiasis complicated with pyonephrosis 145 (44%), malignant disease (n=87; 26%), pregnancy (n=26; 8%), and anatomical abnormality (n=23; 7%). One hundred and twenty three patients had diabetes mellitus. The most common causative organisms were Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Blood cultures showed the same results for the PCN and bladder urine cultures. The bladder urine culture was positive in 304 patients, while the PCN urine culture in 314 patients.

CONCLUSION

PCN is an important treatment for the management of pyonephrosis. Cultures from the PCN yield valuable information that is not available from urethral urine cultures, and is a guiding tool for antibiotic therapy selection.

Blood cultures and bacteraemia in an Australian emergency department: Evaluating a predictive rule to guide collection and their clinical impact

OBJECTIVE

The objective of the present study is to determine whether a predictive rule could safely reduce the number of negative blood cultures collected in an Australian ED and to assess the clinical impact of positive results from blood cultures taken in the ED.

METHODS

All positive blood cultures taken in the ED at a single facility were retrospectively identified for the calendar year 2012. Clinically significant bacteraemia episodes were assessed against a predictive rule using major and minor clinical and laboratory criteria gathered from medical records and pathology databases, and compared with a randomly generated sample of ED patient episode with negative blood cultures. The ED and final diagnoses and blood culture impact on clinical management were also collected.

RESULTS

The predictive rule has a high sensitivity (98.8%) and modest specificity (48.7%), and if applied stringently would have prevented almost half of all blood cultures in our ED but missed two positives. Blood cultures altered the clinical management of 94.3% bacteraemic patients, representing 3.4% of all ED patients with blood cultures performed. High discordance (54%) between ED diagnosis and discharge diagnosis of bacteraemic patients was noted.

CONCLUSIONS

Bacteraemia detected in the ED alters subsequent patient management. The predictive rule can be safely applied in the ED to determine need for blood culture collection. Blood cultures should not be omitted in the ED based entirely on preliminary diagnosis given the high discordance seen between ED and discharge diagnosis.

Best Clinical Practice: Blood Culture Utility in the Emergency Department

BACKGROUND

Bacteremia affects 200,000 patients per year, with the potential for significant morbidity and mortality. Blood cultures are considered the most sensitive method for detecting bacteremia and are commonly obtained in patients with fever, chills, leukocytosis, focal infections, and sepsis.

OBJECTIVE

We sought to provide emergency physicians with a review of the literature concerning blood cultures in the emergency department.

DISCUSSION

The utility of blood cultures has been a focus of controversy, prompting research evaluating effects on patient management. Bacteremia is associated with increased mortality, and blood cultures are often obtained for suspected infection. False-positive blood cultures are associated with harm, including increased duration of stay and cost. This review suggests that blood cultures are not recommended for patients with cellulitis, simple pyelonephritis, and community-acquired pneumonia, because the chance of a false-positive culture is greater than the prevalence of true positive cultures. Blood cultures are recommended for patients with sepsis, meningitis, complicated pyelonephritis, endocarditis, and health care-associated pneumonia. Clinical prediction rules that predict true positive cultures may prove useful. The clinical picture should take precedence. If cultures are obtained, two bottles of ≥7 mL should be obtained from separate peripheral sites.

CONCLUSIONS

Blood cultures are commonly obtained but demonstrate low yield in cellulitis, simple pyelonephritis, and community-acquired pneumonia. The Shapiro decision rule for predicting true bacteremia does show promise, but clinical gestalt should take precedence. To maximize utility, blood cultures should be obtained before antibiotic therapy begins. At least two blood cultures should be obtained from separate peripheral sites.

Comparison of computed tomography findings between bacteremic and non-bacteremic acute pyelonephritis due to Escherichia coli

AIM: To identify computed tomography (CT) findings that are associated with the presence of bacteremia in patients with acute pyelonephritis (APN) due to Escherichia coli (E. coli).

METHODS: The clinical data and contrast-enhanced CT findings of 128 patients who were diagnosed with APN due to E. coli and showed renal abnormality on contrast-enhanced CT between January 2003 and November 2013 were retrospectively reviewed. The patients were divided into two groups according to the presence of bacteremia: The bacteremia group and the non-bacteremia group. The abnormality on contrast-enhanced CT were categorized into 5 renal and 4 extrarenal CT findings and compared between the two groups using the χ² test and multivariate logistic regression.

RESULTS: Among the 128 patients, 34 patients (26.6%) were classified into the bacteremia group and 94 patients (73.4%) into the non-bacteremia group. There was no statistically significant difference in gender between the two groups (P = 0.09), but the age of the patients in the bacteremia group was higher than that of the patients in the non-bacteremia group (P < 0.01). Compared to the non-bacteremia group, 1 renal CT finding such as urothelial thickening and 3 extrarenal CT findings such as diffuse peritoneal thickening, cystitis and pulmonary congestion were more frequently observed in the bacteremia group with statistical significance. The logistic regression analysis revealed that CT findings, including urothelial thickening, diffuse peritoneal thickening, cystitis and pulmonary congestion were suggested as the predictive CT findings of bacteremic APN.

CONCLUSION: On CT, urothelial thickening, diffuse peritoneal thickening, cystitis, and pulmonary congestion are more frequently observed in patients with bacteremic APN due to E. coli.

Clinical and epidemiological features and prognosis of complicated pyelonephritis: a prospective observational single hospital-based study

Background

Complicated pyelonephritis (cPN), a common cause of hospital admission, is still a poorly-understood entity given the difficulty involved in its correct definition. The aim of this study was to analyze the main epidemiological, clinical, and microbiological characteristics of cPN and its prognosis in a large cohort of patients with cPN.

Methods

We conducted a prospective, observational study including 1325 consecutive patients older than 14 years diagnosed with cPN and admitted to a tertiary university hospital between 1997–2013. After analyzing the main demographic, clinical and microbiological data, covariates found to be associated with attributable mortality in univariate analysis were included in a multivariate logistic regression model.

Results

Of the 1325 patients, 689 (52%) were men and 636 (48%) women; median age 63 years, interquartile range [IQR] (46.5-73). Nine hundred and forty patients (70.9%) had functional or structural abnormalities in the urinary tract, 215 (16.2%) were immunocompromised, 152 (11.5%) had undergone a previous urinary tract instrumentation, and 196 (14.8%) had a long-term bladder catheter, nephrostomy tube or ureteral catheter. Urine culture was positive in 813 (67.7%) of the 1251 patients in whom it was done, and in the 1032 patients who had a blood culture, 366 (34%) had bacteraemia. Escherichia coli was the causative agent in 615 episodes (67%), Klebsiella spp in 73 (7.9%) and Proteus ssp in 61 (6.6%). Fourteen point one percent of GNB isolates were ESBL producers. In total, 343 patients (25.9%) developed severe sepsis and 165 (12.5%) septic shock. Crude mortality was 6.5% and attributable mortality was 4.1%. Multivariate analysis showed that an age >75 years (OR 2.77; 95% CI, 1.35-5.68), immunosuppression (OR 3.14; 95% CI, 1.47-6.70), and septic shock (OR 58.49; 95% CI, 26.6-128.5) were independently associated with attributable mortality.

Conclusions

cPN generates a high morbidity and mortality and likely a great consumption of healthcare resources. This study highlights the factors directly associated with mortality, though further studies are needed in the near future aimed at identifying subgroups of low-risk patients susceptible to outpatient management.

Diagnostic usefulness of procalcitonin as a marker of bacteremia in patients with acute pyelonephritis

BACKGROUND

Acute pyelonephritis (APN) is one of the most common community-acquired infections and frequently accompanies bacteremia. The purpose of this study was to investigate the diagnostic role of procalcitonin in predicting bacteremia in patients with APN.

METHODS

We conducted a retrospective study of patients with APN who visited the emergency department (ED) at Samsung Medical Center, Seoul. Predictors of bacteremia were analyzed and receiver operating characteristics (ROC) curves were plotted for procalcitonin, C-reactive protein (CRP), and leukocytes.

RESULTS

During the study period, a total of 147 patients who had microbiologically proven APN and available initial procalcitonin concentrations were identified. Of these, bacteremia was present in 84 patients. Multivariate analysis showed that age, hypotension, and higher procalcitonin concentrations independently predicted the presence of bacteremia. Procalcitonin had better discriminative power than CRP, as reflected by area under the ROC curve analysis (0.746 [95% CI, 0.667-0.826] vs. 0.602 [95% CI, 0.509-0.694], p = 0.02). At a cut-off value of 1.63 μg/L, procalcitonin predicted bacteremia with a sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 61.9, 81.0, 81.3, 61.4 and 70.1%, respectively.

CONCLUSION

Procalcitonin concentration could be used as a reliable marker to predict bacteremia in patients with APN in the ED.

Blood cultures for evaluation of early postoperative fever after femoral neck fracture surgery

PURPOSE

To evaluate the utility of blood cultures in the assessment of early postoperative fever in hip fracture patients with no other indicators of sepsis.

METHODS

101 blood cultures were drawn on postoperative days 0 to 5 to investigate 84 febrile episodes in 31 women and 30 men (mean age, 80 years) whose body temperature measured via the tympanic route was ≥ 38 ºC. Culture results of these 61 patients were divided into culture-positive and culture-negative groups for comparison.

RESULTS

Of the 101 blood cultures, only 2 were positive: one was obtained 5 days after dynamic hip screw fixation, and the other 4 days after hemiarthroplasty. Both blood cultures grew coagulase-negative staphylococcal species, which were deemed to be skin contaminants not requiring change of patient management. 44 of these patients were treated with oral or intravenous antibiotics for a period of time.

CONCLUSION

The risk of bacteraemia in patients with postoperative fever but no other symptoms of infection is low. Routine procurement of blood cultures in such patients is ineffective and of limited utility.

Predictors of bacteremia in emergency department patients with suspected infection

OBJECTIVES

The goal of this study is to identify clinical variables associated with bacteremia. Such data could provide a rational basis for blood culture testing in emergency department (ED) patients with suspected infection.

METHODS

This is a secondary analysis of a prospective cohort of ED patients with suspected infection. Data collected included demographics, vital signs, medical history, suspected source of infection, laboratory and blood culture results and outcomes. Bacteremia was defined as a positive blood culture by Centers for Disease Control criteria. Clinical variables associated with bacteremia on univariate logistic regression were entered into a multivariable model.

RESULTS

There were 5630 patients enrolled with an average age of 59.9 ± 19.9 years, and 54% were female. Blood cultures were obtained on 3310 (58.8%). There were 409 (12.4%) positive blood cultures, of which 68 (16.6%) were methicillin-resistant Staphylococcus aureus (MRSA) and 161 (39.4%) were Gram negatives. Ten covariates (respiratory failure, vasopressor use, neutrophilia, bandemia, thrombocytopenia, indwelling venous catheter, abnormal temperature, suspected line or urinary infection, or endocarditis) were associated with all-cause bacteremia in the final model (c-statistic area under the curve [AUC], 0.71). Additional factors associated with MRSA bacteremia included end-stage renal disease (odds ratio [OR], 3.9; 95% confidence interval [CI], 1.9-7.8) and diabetes (OR, 2.0; 95% CI, 1.1-3.6) (AUC, 0.73). Factors strongly associated with Gram-negative bacteremia included vasopressor use in the ED (OR, 2.8; 95% CI, 1.7-4.6), bandemia (OR, 3.5; 95% CI, 2.3-5.3), and suspected urinary infection (OR, 4.0; 95% CI, 2.8-5.8) (AUC, 0.75).

CONCLUSIONS

This study identified several clinical factors associated with bacteremia as well as MRSA and Gram-negative subtypes, but the magnitude of their associations is limited. Combining these covariates into a multivariable model moderately increases their predictive value.

[Urinary tract colonization and infection in critically ill patients]

Urinary tract infections (UTIs) account for 20-50% of all hospital-acquired infections occurring in the intensive care unit (ICU). In some reports UTI was found to be more frequent than hospital-acquired pneumonia and intravascular device bacteremia, with a greater incidence in developing countries. The risk factors associated with the appearance of UTI include the severity of illness at the time of admission to the ICU, female status, prolonged urinary catheterization or a longer ICU stay and poor urinary catheter management - mainly disconnection of the closed system. about the present study offers data on the epidemiology of UTI in the ICU, the identified risk factors, etiology, diagnosis, impact upon morbidity and mortality, and the measures to prevent its appearance.

A simple model to predict bacteremia in women with acute pyelonephritis

OBJECTIVES

To construct a simple model to predict bacteremia in women with uncomplicated acute pyelonephritis (APN) for the judicious use of blood cultures.

METHODS

A prospective database including 735 women with uncomplicated APN at an academic urban emergency department was analyzed retrospectively. Independent risk factors were determined using multivariate logistic regression in two-thirds of patients. Cutoff values representing 10% and 30% of risk were selected for the stratification. This model was internally and externally validated using a remaining one-thirds of patients and 169 independent patients, respectively.

RESULTS

Independent risk factors were as follows: age ≥65 years (odds ratio [OR]=5.18, 4 points), vomiting (OR=2.40, 2 points), heart rate >110 beats/min (OR=2.35, 2 points), segmented neutrophils >90% (OR=3.17, 3 points), and urine WBC ≥50/HPF (OR=4.27, 4 points). Patients were stratified as low (points <4), intermediate (points, 4-6), or high risk (7≤ points). The areas under receiver operating characteristics curves were 0.707 and 0.792 in internal and external validation cohorts, respectively. The model stratified internal and external validation cohort into low (8.5% and 5.7%), intermediate (16.5% and 14.8%), and high risk of bacteremia (42.0% and 56.4%).

CONCLUSIONS

This model provides a useful tool to predict the risk of bacteremia, which can be helpful to decide whether to perform blood cultures and whether to admit the patient for the intravenous antibiotics in women with uncomplicated APN.

Association between the number of blood cultures and appropriateness of care for suspected bacteremic urinary tract infection in the elderly

The objective of this study was to evaluate the association between the number of blood cultures collected and the appropriateness of care for suspected bacteremic community-acquired urinary tract infection (UTI) in the elderly. We retrospectively evaluated the medical records of 129 patients with UTI > 65 years old admitted to a large community-based training hospital in Japan from 1 January 2006 to 31 December 2009. We assessed the association between the number of blood cultures collected and the appropriateness of care received, as well as other factors. Two-thirds of the patients were women, and patients > 85 years old accounted for 45.0% of the cases. Most of the organisms isolated from the urine and blood were Escherichia coli (65.4-67.0%). More than two blood cultures were collected 79.1% of the time, and 66.7% of the cases were evaluated as having been treated appropriately. The appropriateness of care was not significantly related to the number of blood cultures. The appropriateness of care received in the general internal medicine department was significantly higher (p = 0.016) than that in other departments. Thus, the appropriateness of care for suspected bacteremic UTI in the elderly was not significantly associated with the number of blood cultures. However, the department of hospitalization may have influenced the appropriateness of care.

Pyelonephritis in pregnancy: an update on treatment options for optimal outcomes

Acute pyelonephritis is one of the most common indications for antepartum hospitalization. When acute pyelonephritis is diagnosed, conventional treatment includes intravenous fluid and parenteral antibacterial administration. There are limited data by which to assess the superiority of one antibacterial regimen over the other in terms of efficacy, patient acceptance and safety for the developing fetus; however, it is important to consider antimicrobial resistance patterns in the local community when choosing an agent. Moreover, there are growing public health concerns regarding antimicrobial resistance to commonly prescribed medications for urinary tract infections in pregnancy. There is a small body of evidence to support the ambulatory treatment of pregnant women with pyelonephritis in the first and early second trimesters, but the majority of women will be managed as inpatients. This article provides a suggested algorithm for the treatment of pyelonephritis during pregnancy.

Who needs a blood culture? A prospectively derived and validated prediction rule

The study objective was to derive and validate a clinical decision rule for obtaining blood cultures in Emergency Department (ED) patients with suspected infection. This was a prospective, observational cohort study of consecutive adult ED patients with blood cultures obtained. The study ran from February 1, 2000 through February 1, 2001. Patients were randomly assigned to derivation (2/3) or validation (1/3) sets. The outcome was "true bacteremia." Features of the history, co-morbid illness, physical examination, and laboratory testing were used to create a clinical decision rule. Among 3901 patients, 3730 (96%) were enrolled with 305 (8.2%) episodes of true bacteremia. A decision rule was created with "major criteria" defined as: temperature > 39.5 degrees C (103.0 degrees F), indwelling vascular catheter, or clinical suspicion of endocarditis. "Minor criteria" were: temperature 38.3-39.4 degrees C (101-102.9 degrees F), age > 65 years, chills, vomiting, hypotension (systolic blood pressure < 90 mm Hg), neutrophil% > 80, white blood cell count > 18 k, bands > 5%, platelets < 150 k, and creatinine > 2.0. A blood culture is indicated by the rule if at least one major criterion or two minor criteria are present. Otherwise, patients are classified as "low risk" and cultures may be omitted. Only 4 (0.6%) low-risk patients in the derivation set and 3 (0.9%) low-risk patients in the validation set had positive cultures. The sensitivity was 98% (95% confidence interval [CI] 96-100%) (derivation) and 97% (95% CI 94-100%) (validation). We developed and validated a promising clinical decision rule for predicting bacteremia in patients with suspected infection.

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.

Are blood cultures necessary in the management of women with complicated pyelonephritis?

OBJECTIVES

Data from previous studies suggest that blood cultures in women with uncomplicated acute pyelonephritis (APN) are of limited value. Our objective was to assess the role of blood cultures in the management of complicated APN in women, and to examine the demographic and clinical characteristics, and the outcome as related to the bacteremic status of these patients.

METHODS

Data from medical records of 158 women hospitalized with complicated APN over a 2-year period were analyzed retrospectively. It included demographic, clinical and laboratory data, details of the empiric antimicrobial therapy, urine and blood culture results, complications and clinical outcome.

RESULTS

Out of 158 women with complicated APN, in 155 (98%) pathogens grew in the urine culture, and 33 (20.9%) of them had bacteremia. In the great majority of patients (98.7%), the blood cultures were sterile, or contained the same phenotypically profiled pathogen that was isolated from the urine. Only in two patients (1.3%), the blood cultures grew pathogens different from those found in the urine. The initial empiric antimicrobial therapy was not changed in any of the patients. No significant difference existed between the bacteremic and nonbacteremic patients in the demographic and clinical characteristics, the severity of disease or the outcome.

CONCLUSION

In the management of complicated APN, routine cultures of blood should be reevaluated.

[Retrospective study of bacteremia diagnosed in an emergency department: frequency, susceptibility of microorganisms, and impact on therapeutic management]

OBJECTIVE

The authors had for aim to determine the prevalence of bacteremia diagnosed in an emergency department (ED), the susceptibility of microorganisms to antibiotics, and the impact on therapeutic management.

DESIGN

A retrospective analysis was made on patient features, microbiological ecology, susceptibility to antibiotics, and modalities of antimicrobial therapy in the Georges Pompidou European hospital ED of Hôpital, between 1 November 2001 and 30 June 2002.

RESULTS

One thousand four hundred and thirty two blood cultures were obtained from 1069 patients. The rate of positive cultures was 12%, but only 8.7% (n = 125) were proved as true bacteremia. The most frequently identified organisms were: Enterobacteriaceae (n = 63, 39.4%) with a predominance of Escherichia coli (n = 48, 30%), and Streptococcus pneumoniae (n = 16, 10%). Forty two cases of pyelonephritis and 34 of prostatitis both due to E. coli were diagnosed. 76.5% of these were resistant to amoxicillin, 64.7% to amoxicillin-clavulanic acid, 11.8% to ciprofloxacin, and 44% to cotrimoxazole. No resistance to third generation cephalosporin was detected in E. coli isolates. Fourteen S. pneumoniae pneumonia cases were diagnosed. 57.1% of isolates presented with a decreased susceptibility to penicillin (CMI > 0.1 mg/l). Susceptibility to amoxicillin and cefotaxim was 85.7% and 92.9% respectively. Blood culture was the only exam available for bacterial diagnosis in 51.5% of true bacteremia. 1.6% of blood cultures from ED samples had an impact on therapeutic management.

CONCLUSIONS

Blood culture is a relevant exam for the diagnosis of infection in patients admitted to the ED.

Acute pyelonephritis among adults: cost of illness and considerations for the economic evaluation of therapy

Urinary tract infection (UTI) is an infection anywhere in the urinary tract, most commonly due to bacteria. If infection involves the kidney, the UTI is termed acute pyelonephritis (APN). An estimated 10-30% of all patients with APN are hospitalised for treatment; in the US, the incidence of hospitalisation is 11.7 per 10,000 for women and 2.4 per 10,000 for men. Perhaps because of the generally good prognosis of APN when treated with current antibacterial therapies, there have been relatively few studies of patient management and therapeutic options for the disease, or of its epidemiology and risk factors. The most cost-effective outpatient management strategy (immediate discharge, observation followed by discharge, etc.) is currently unknown. Appropriate antimicrobial selection is clearly important, as treatment failures will increase the cost of care and result in additional morbidity for patients. The direct and indirect costs of APN are significant: an estimated 2.14 billion US dollars (year 2000 values). Cost estimates are most sensitive to hospitalisation rates, which are unknown in the US. Additional studies are needed to better define when in-hospital treatment is required. As the pathogens causing APN are increasingly becoming resistant to current therapies, not only are clinical trials in order to test the effectiveness of alternative therapies, but epidemiological studies to identify risk factors for infection with a resistant isolate and effective prevention strategies are required, especially among those with previous episodes of APN.

Blood cultures for women with uncomplicated acute pyelonephritis: are they necessary?

To assess the utility of blood cultures in the management of uncomplicated pyelonephritis in women, we prospectively collected data from 583 cases. Discordant cases were defined as those for which the pathogens isolated from urine and from blood were different. We found that 97.6% of cases were nondiscordant. Clinical and microbiological evolution of infection did not differ between the 2 groups, and no changes of antibiotic therapy were required on the basis of blood culture results. Blood culture may not be routinely required for the evaluation of uncomplicated pyelonephritis in women.

Utility of blood cultures in febrile children with UTI

The objective of the study was to define the prevalence of bacteremia in febrile children <18 years of age diagnosed to have acute urinary tract infection (UTI). Retrospective chart review of patients diagnosed to have a UTI in the emergency department (ED) of an urban, tertiary care children's hospital was conducted Seven hundred forty-four children were discharged or admitted from the ED with a diagnosis of UTI during the study period. Thirty-six (4.8%) patient records were unavailable for review; 343 met inclusion criteria. Two hundred forty-nine patients (72.8%) had a history of fever. Blood cultures were performed on 183 (53.4%) patients. Of febrile patients, 178 (71.5%) had a blood culture performed. Seventeen of 183 (9.3%) blood cultures were positive. All (17/178, 9.5%) positive blood cultures were obtained from febrile patients. Seven of the positive blood cultures were considered to be contaminated. The prevalence of true bacteremia in febrile patients was 5.6%. All 10 patients with a true pathogen recovered from the blood culture had the same organism in their urine culture. The prevalence of bacteremia in patients younger than 2 months was 22.7% and in patients between the ages of 2 months and 36 months, 3.0%. Patients with a positive blood culture were more likely to be younger, to have been hospitalized and to have had a longer duration of hospitalization. No difference was found between patients with a positive blood culture and those without in regards to the number of days of illness before presentation, time to defervescence and mean white blood cell count. Bacteremia in children with UTI is most common in very early infancy. Children with UTI between the ages of 2 months and 12 years appear to have a low risk of bacteremia. Children who are bacteremic are likely to have identical organisms with identical antimicrobial sensitivities in both the urine and blood culture.

Pyelonephritis in pregnancy: treatment options for optimal outcomes

Acute pyelonephritis is one of the most common indications for antepartum hospitalisation. When acute pyelonephritis is diagnosed, conventional treatment includes intravenous fluid and parenteral antibacterial administration. There are limited data by which to assess the superiority of one antibacterial regimen over the other in terms of efficacy, patient acceptance and safety for the developing fetus. There is a small body of evidence to support the ambulatory treatment of pregnant women with pyelonephritis in the first and early second trimesters.

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.

Urinary tract infection and pyelonephritis

UTIs are common, potentially severe infections that the emergency physician must manage efficiently and effectively. In most cases, this entity is well recognized, and the clinician will be confident of the correct course. However, in certain populations, complications are common, and the best therapy has yet to be proven. Tailoring the evaluation and treatment to the risk of complications is imperative. With careful evaluation, individualized therapy and close follow-up, the majority of patients can be expected to do well.

Predictive factors associated with significant urinary tract abnormalities in infants with pyelonephritis

BACKGROUND

Major urinary tract abnormalities are detected in 20 to 40% of infants with acute pyelonephritis (APN). Early detection of structural defects is essential for protecting the kidneys from reinfection and subsequent scarring. The purpose of this study was to investigate whether any factors present during the acute phase of infection could predict the presence of existing significant urinary tract abnormalities in infants.

METHODS

A prospective study of 180 infants, aged 1 to 24 months, with APN was conducted. Blood and urine samples were collected. Renal ultrasound (US) was performed within 0 to 6 days from admission. Final diagnosis of the urinary tract anatomy was elucidated using the results of two or more radiologic imaging studies.

RESULTS

Risk factors for the presence of significant urinary tract abnormalities in infants were pathogens other than Escherichia coli in urine [relative risk (RR) 3.4, 95% confidence interval (CI) 2.2 to 5.3; P = 0.001], positive blood culture (RR 2.3, 95% CI 1.3 to 4.0; P = 0.039), young age (1 to 6 months) (RR 2.2, 95% CI 1.3 to 3.9; P = 0.004), lack of papG adhesin genes of E. coli in urine (RR 2.1, 95% CI 1.2 to 3.9; P = 0.016) and abnormal renal US (RR 2.0, 95% CI 1.2 to 3.4; P = 0.008).

CONCLUSIONS

Infants 1 to 6 months of age with APN caused by bacteria other than E. coli or by papG-negative E. coli strain, positive blood culture and abnormal renal US carry an increased risk for significant urinary tract abnormalities and need enforced follow-up.

Limited clinical utility of blood and urine cultures in the treatment of acute pyelonephritis during pregnancy

OBJECTIVE

The purpose of this study was to determine the utility of urine and blood cultures in the clinical management of pregnant women with acute pyelonephritis.

STUDY DESIGN

Data were pooled from three randomized controlled trials that were conducted at two university-based tertiary care centers and included 391 pregnant women with pyelonephritis. The results of urine and blood cultures were correlated with clinical management decisions, outcome, length of hospital stay, and cost.

RESULTS

Results of 98% of urine cultures (382/391) and 99% of blood cultures (388/391) were available for analysis. The most common pathogen isolated was Escherichia coli, which was found in 79% of the urine cultures (300/382) and in 77% of the blood cultures (27/35). Susceptibility testing revealed 46% resistance to ampicillin; 7%, 2%, and 0% resistances to first-, second-, and third-generation cephalosporins, respectively; and 1% resistance to gentamicin. Six percent of the participants (25/391) required changes in antibiotic therapy, most commonly for persistent fever (6/25, 25%). Positive blood culture results directly influenced management by prolonging the duration of hospitalization, with means of 4.6 +/- 2.6 hospital days for women with bacteremia and 2.6 +/- 1.5 hospital days for women without bacteremia (P <.001) despite similar durations of symptoms.

CONCLUSION

Urine and blood cultures with sensitivity testing had limited utility in the clinical management of pregnant women with pyelonephritis. Decisions to change antibiotic treatment were affected more by clinical course than by culture results. We suggest that elimination of blood and urine cultures might simplify management and result in significant cost savings without compromising patient care.

The detection of positive blood cultures by the AccuMed ESP-384 system: the clinical significance of three-day testing

A total of 805 positive blood cultures obtained over a 4-month period during 1997 by the AccuMed ESP-384 system were evaluated and compared with 471 positive blood cultures obtained during 1989. Of the 805 microorganisms isolated in 5-day culture and testing by the ESP-384, 671 (83.4%) were detected within the first 2 days and 758 (94.2%) within 3 days. There were 47 (5.7%) microorganisms detected in culture Days 4 and 5 from 42 patients and review of the medical records from these patients demonstrated that no significant changes in clinical management were instituted as a result of detection and identification of these isolates. These 47 organisms were considered to be zero to equivocal clinical relevance. These data suggest that a 3-day routine blood culture incubation protocol with the ESP-384 system may be sufficient when considering detection rate, clinical relevance, and cost-effectiveness. The microbial spectrum and relative frequencies in this study were found to be similar to those of positive blood cultures obtained during 1989.

Clinical impact of blood cultures taken in the emergency department

OBJECTIVES

(1) To establish the proportion of blood cultures that yield a positive microbiological culture. (2) To determine what proportion of blood cultures taken in the emergency department impact on patient management. (3) To develop guidelines for the appropriate ordering of blood cultures from patients in the emergency department (ED).

METHODS

Retrospective review of all blood cultures taken in the ED of a metropolitan teaching hospital between 26 September 1995 and 30 June 1996.

RESULTS

One thousand and sixty two blood cultures were taken from patients in the ED during the study period. Ninety two (9%) returned a positive microbiological culture. Of these, 52 (5%) were "true" positives and 18 (1.6%) resulted in changes in management.

CONCLUSIONS

Blood cultures taken in the ED rarely yield positive cultures. Only 1.6% of blood cultures taken in the ED impact on management of patients. Simple strategies could reduce the number of blood cultures ordered with little prospect of patient compromise.