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Occult bacteremia in young febrile children.

The evaluation of nontoxic-appearing, young, febrile children has been a subject of considerable debate. Of young, nontoxic-appearing children aged 3 to 36 months with temperatures of 39 degrees C or more and no clear source, approximately 2% to 3% have occult bacteremia. Of these bacteremias, approximately 90% are caused by S. pneumoniae, 5% by nontyphoidal Salmonella sp., and 1% by N. meningitidis. Most children with occult pneumococcal bacteremia improve spontaneously, but approximately 25% of untreated patients have persistent bacteremia or develop new focal infections, including 3% to 6% who develop meningitis. Occult meningococcal bacteremia, although rare, has frequent complications, including meningitis in approximately 40% and death in approximately 4%. Less is known about the natural history of untreated occult nontyphoidal Salmonella bacteremia. Empiric antibiotic treatment of children with occult bacteremia decreases the rate of complications, including meningitis. Few disagree that febrile, young children at risk for occult bacteremia require a careful clinical evaluation and close follow-up. The benefits of laboratory screening and selective empiric antibiotic treatment of febrile children at risk for occult bacteremia have to be weighed against the costs of screening tests and blood cultures, inconvenience, temporary discomfort to patients, risk for side effects of antibiotics, and the role of antibiotics in the development of bacterial resistance. Although great debate exists concerning the role of empiric antibiotics, a strategy for obtaining blood cultures and empirically administering antibiotics on the basis of an increased ANC, in addition to close clinical follow-up, may be effective in reducing the frequency and severity of uncommon but adverse sequelae. A highly effective S. pneumoniae bacterial conjugate vaccine will soon be available, which will benefit all children, and will alter the ways that clinicians evaluate fully immunized young, febrile children.

Anti-Bacterial Agents↗

Persistence in Staphylococcus aureus bacteremia: incidence, characteristics of patients and outcome.

Staphylococcus aureus bacteremia often persists. The reasons for persistence and its outcome are poorly defined. We conducted a prospective-observational study among 245 consecutive S. aureus (MRSA: n=125; MSSA: n=120) bacteremias (>or=1 positive blood cultures (BC)) among 234 adults (18-103-y-old; median=59 y) hospitalized during 1 January 2002-31 December 2002 at a 600-bed teaching hospital. Measurements included bacteremia duration, complication-rate (metastatic infection, relapse or attributable mortality) and outcome. Bacteremia duration was measured based on follow-up BC among 193 patients and estimated based on symptoms resolution in the rest. Measured (1-59 d; median=2) and estimated (median=1 d) duration correlated (r=0.885) though positive follow-up BC was often detected without fever (57/105 patients, 54.3%). Persistence (defined as bacteremia for >or=3 d) was noted in 84 cases (38.4%). Complication-rate increased steadily with bacteremia duration (6.6%, 24.0% and 37.7% in bacteremia for 1-2, 3 and >or=4 d, respectively; p=0.05). Cox regression analysis revealed that bacteremia duration correlated positively with endovascular sources (p=0.006), vancomycin treatment (p=0.016), cardiovascular prosthesis (p=0.025), metastatic infections (p=0.025) and diabetes (p=0.038). It is concluded that persistent bacteremia is a feature of S. aureus infection, irrespective of oxacillin susceptibility, associated with worse outcome. Risk factors include endovascular sources, cardiovascular prosthesis, metastatic infections, vancomycin treatment and diabetes. Patients at risk may benefit from novel treatment strategies.

Adolescent↗

Polyclonal bacteremia due to gram-negative rods.

The frequency of, risk factors for, and outcome of polyclonal gram-negative bacteremia are still unknown. We investigated them in a prospective cohort study of patients for whom a blood culture yielded >/=1 species of gram-negative aerobic rod. For each patient, pulsed field gel electrophoresis (PFGE) was performed on 4 colonies of each morphologic type. Episodes of bacteremia were considered polyclonal if caused by >1 PFGE type of the same species. Ten (6.5%) of 153 investigated patients had polyclonal bacteremia. Bacteremia due to nonfermenting rods was the single significant risk factor for polyclonal bacteremia. Complications were equally frequent in all patient groups. However, patients with polyclonal bacteremia received more extensive antibiotic therapy than did patients with monoclonal bacteremia. Nearly 20% of episodes of bacteremia due to nonfermenting rods were polyclonal, but it remains unclear why nonfermenting rods were more likely to cause polyclonal bacteremia than were other gram-negative rods.

Anti-Bacterial Agents↗

Burden of community-onset Escherichia coli bacteremia in seniors.

BACKGROUND: Although Escherichia coli is a well-recognized cause of urinary tract infection in seniors, little is known about the burden of invasive E. coli infection in this population. METHODS: We conducted a population-based cohort study of 46,238 noninstitutionalized Group Health Cooperative members>or=65 years of age to ascertain incidences of community-onset E. coli bacteremia and, for comparison, pneumococcal bacteremia, and we then performed a case-control study to identify risk factors for community-onset E. coli bacteremia. RESULTS: The overall rate of community-onset E. coli bacteremia in the study cohort was 150 cases/100,000 person-years, which was approximately 3 times higher than the rate of pneumococcal bacteremia. In the case-control study, urinary catheterization and urinary incontinence were the only factors associated with an increased risk of E. coli bacteremia in men (62 cases), whereas cancer, renal failure, congestive heart failure, coronary artery disease, and urinary incontinence were associated with an increased risk of E. coli bacteremia in women (119 cases). CONCLUSIONS: E. coli appears to be the leading cause of community-onset bacteremia in seniors, and, on the basis of these rates, we estimate that 53,476 cases occur in noninstitutionalized seniors each year in the United States. Community-onset E. coli bacteremia in seniors is, therefore, an infection of public health importance.

Aged↗

Frequency of permanent pacemaker or implantable cardioverter-defibrillator infection in patients with gram-negative bacteremia.

BACKGROUND: Despite the frequent occurrence of bacteremia due to gram-negative organisms in patients with underlying permanent pacemakers (PPMs) or implantable cardioverter defibrillators (ICDs), the outcome and treatment of these patients has received scant attention. In patients with PPMs or ICDs who have Staphylococcus aureus bacteremia, 45% have PPM/ICD infection. METHODS: We conducted a retrospective cohort study over a 7-year period to assess the clinical features and frequency of PPM/ICD infection in patients with gram-negative bacteremia, as well as the incidence of relapse in patients for whom the device was not removed. RESULTS: Forty-nine patients were included in the study; 3 (6%) had either definite (2 patients) or possible (1 patient) PPM/ICD infection. Both patients with definite PPM/ICD infection had clear infection of the generator pocket. None of the other patients with alternate sources of bacteremia developed PPM/ICD infection. Thirty-four patients with retained PPM/ICD were observed for >12 weeks (median time, 759 days), and 2 (6%) developed relapsing bacteremia, although they each had alternative sources of relapse. CONCLUSIONS: In sharp contrast to S. aureus infection, PPM/ICD infection in patients with gram-negative bacteremia was rare, and no patients appeared to have secondary PPM/ICD infection due to hematogenous seeding of the system. Despite infrequent system removal in these patients, relapsing bacteremia among patients who survived initial bacteremia was rarely seen. If secondary PPM/ICD infection occurs in patients with gram-negative bacteremia, it is either uncommon or it is cured with antimicrobial therapy despite device retention.

Aged↗

Impact of routine intensive care unit surveillance cultures and resultant barrier precautions on hospital-wide methicillin-resistant Staphylococcus aureus bacteremia.

BACKGROUND: Serial interventions are often used to reduce the risk of health care-associated methicillin-resistant Staphylococcus aureus (MRSA) infections. To our knowledge, the relative impact of these interventions has not previously been ascertained. METHODS: We conducted a retrospective study of 4 major infection control interventions using an interrupted time series design to evaluate their impact on MRSA bacteremia in an 800-bed hospital with 8 intensive care units (ICUs). Interventions were introduced 1 at a time during a 9-year period and involved the promotion of compliance with maximal sterile barrier precautions during central venous catheter placement, the institution of alcohol-based hand rubs for hand disinfection, the introduction of a hand hygiene campaign, and the institution of routine nares surveillance cultures for MRSA in all ICUs for patients on ICU admission and weekly thereafter while in the ICU. Positive cultures resulted in the initiation of contact isolation precautions. Using segmented regression analyses, we evaluated changes in monthly incidence and prevalence of MRSA bacteremia from their predicted values. Methicillin-susceptible Staphylococcus aureus bacteremia was monitored as a control. RESULTS: Routine surveillance cultures and subsequent contact isolation precautions resulted in substantial reductions in MRSA bacteremia in both ICUs and non-ICUs. In 16 months, the incidence density of MRSA bacteremia decreased by 75% in ICUs (P=.007) and by 40% in non-ICUs (P=.008), leading to a 67% hospital-wide reduction in the incidence density of MRSA bacteremia (P=.002). Methicillin-susceptible S. aureus bacteremia rates remained stable during this time. The other interventions were not associated with a statistically significant change in MRSA bacteremia. CONCLUSIONS: Routine surveillance for MRSA in ICUs allowed earlier initiation of contact isolation precautions and was associated with large and statistically significant reductions in the incidence of MRSA bacteremia in the ICUs and hospital wide. In contrast, no similar decrease was attributable to the other infection control interventions.

Bacteremia↗

Emergence of quinolone-resistant Escherichia coli bacteremia in neutropenic patients with cancer who have received prophylactic norfloxacin.

Between January 1988 and December 1992, 35 episodes of Escherichia coli bacteremia were identified in a series of 230 cases of bacteremia in neutropenic patients with cancer. Thirteen episodes (37%) were due to quinolone-resistant strains. Minimal inhibitory concentrations of norfloxacin ranged from 16 micrograms/mL to 128 micrograms/mL, and those of ciprofloxacin from 8 micrograms/mL to 64 micrograms/mL. The incidence of bacteremia due to quinolone-resistant E. coli increased from zero episodes per 1,000 hospital admissions in 1988 to four episodes per 1,000 admissions in 1992 (P = .018). To identify risk factors for quinolone-resistant E. coli bacteremia, we compared episodes of quinolone-resistant and quinolone-susceptible E. coli bacteremia. Among the variables analyzed, prophylaxis with norfloxacin was the only factor significantly associated with the development of quinolone-resistant E. coli bacteremia; 13 of 13 patients with bacteremia due to resistant strains received norfloxacin, whereas only one (5%) of 22 patients with bacteremia due to susceptible strains did (P < .001). According to our data, neutropenic patients with cancer who receive fluoroquinolone prophylaxis may be at risk of developing E. coli bacteremia due to quinolone-resistant strains.

Adult↗

Exposure to cytomegalovirus from the donated organ is a risk factor for bacteremia in orthotopic liver transplant recipients. Boston Center for Liver Transplantation CMVIG Study Group.

To define predictors of bacteremia and to assess the potential role of exposure to cytomegalovirus (CMV) as a risk factor for bacteremia in liver transplant recipients, an intention-to-treat analysis of data for 146 orthotopic liver transplant recipients who participated in a multicenter, randomized, intervention trial was undertaken. Fifty-eight episodes of bacteremia occurred in 40 (27.4%) of 146 patients within 1 year after transplantation. Bacteremia was diagnosed a median of 39.5 days (range, 1-325 days) after transplantation. One-year mortality rates were higher among patients with bacteremia than among those without bacteremia (47.5% [19 of 40] vs. 18% [19 of 106], respectively; P = .001). A time-dependent multivariate analysis of variables that were significantly (P < or = .05) associated with bacteremia in the univariate analysis showed that donor CMV seropositivity (relative risk [RR], 3.4; 95% confidence interval [CI], 1.6-6.6; P = .0005), age of younger than 16 years (RR, 2.6; 95% CI, 1.3-5.2; P < .0059), and a major abdominal operation after transplantation excluding retransplantation (RR, 3.8; 95% CI, 1.8-8.0; P = .0004) were independently associated with bacteremia. These epidemiologic data suggest that exposure to CMV from the donated organ is an independent risk factor for bacteremia in orthotopic liver transplant recipients.

Bacteremia↗

Prospective study of 125 cases of Staphylococcus aureus bacteremia in children in New Zealand.

BACKGROUND: Staphylococcus aureus bacteremia is a common complication of S. aureus infection. There are few pediatric studies defining the incidence and associated morbidity and mortality of S. aureus bacteremia and no such New Zealand studies. We conducted a prospective study of S. aureus bacteremia in children in New Zealand. METHODS: From July 1, 1996 to December 31, 1998, we included all children < 16 years of age with S. aureus bacteremia in Auckland and Christchurch. Relevant information regarding patient demographics, clinical course and outcome and laboratory results was recorded. RESULTS: One hundred twenty-five cases of true S. aureus bacteremia were identified. There were 4 deaths within 30 days of the onset of bacteremia. Fourteen (11%) of the children were < 1 month of age. Maori children (relative risk, 2.0; 95% confidence interval, 1.3 to 3.2) were twice as likely and Pacific Island children (relative risk, 2.5; 95% confidence interval, 1.6 to 3.8) 2.5 times as likely as white children to acquire S. aureus bacteremia. The peak incidence of S. aureus bacteremia was observed in Pacific Island children < 1 year of age (105 cases/100,000 children/year). Twenty-seven percent of cases were related to intravenous catheters. Seventy percent of cases were community-acquired. Ninety-eight percent of non-catheter-related cases in children > 1 month of age were community-acquired. There was a low rate of methicillin resistance (6%). CONCLUSIONS: S. aureus bacteremia is largely community-acquired in children in New Zealand and is more common in Pacific Island and Maori populations. Although there is a low associated mortality, a significant number are potentially preventable cases secondary to intravenous catheters.

Adolescent↗

HIV-associated bacteremia: how it has changed in the highly active antiretroviral therapy (HAART) era.

To evaluate the changing characteristics of HIV-associated bacteremia in the highly active antiretroviral therapy (HAART) era, we conducted a prospective case control study, comparing two periods of time, before (period A) and after (period B) the introduction of HAART. In total, 174 patients with bacteremia and 348 controls were studied. By comparing incidence in periods A and B, a statistically significant reduction of bacteremia, from 11.8 to 6.3/100 person-years (PY), was observed (p = .0001). Incidence of hospital-acquired bacteremia decreased from 5.8 episodes/100 PY in period A to 2.4/100 PY in period B (p = .0005). A similar trend was also observed for community-acquired episodes of bacteremia, with a value close to statistical significance. Logistic regression analysis indicated that intravenous drug abuse, central venous catheter (CVC) use, high value on APACHE III score, and neutropenia were independent risk factors for bacteremia in both the study periods. Interestingly, comparing the prevalence of bacteremia risk factors in the two study periods, we observed a significant reduction in the use of CVC (p = .04, period A versus period B) and in neutropenia (p = .04). The crude mortality rate was 31% in period A and 23% in period B (p = not significant [ns]). Logistic regression analysis indicated that an high value of Acute Physiology and Chronic Health Evaluation III (APACHE III) score (p < .001) predicted an increased risk of death. Analysis of prognostic factors of bacteremia did not significantly differ in both the study periods. We conclude that HAART has determined a significant reduction of the incidence and a modification of the characteristics of bacteremia. This reduced incidence may produce a substantial impact on future morbidity and health care costs of patients with HIV.

AIDS-Related Opportunistic Infections↗

Predicting bacteremia in children with fever and chemotherapy-induced neutropenia.

BACKGROUND: Fever and neutropenia are common clinical problems in pediatric oncology and frequently necessitate emergency hospitalization and immediate empiric broad spectrum antimicrobial therapy. Estimating the risk of bacteremia in fever and neutropenia is a challenge. The purpose of this study was to develop an algorithm predicting the risk of bacteremia and Gram-negative bacteremia in children and adolescents with fever and neutropenia, based on information accessible at presentation. METHODS: We collected information available within 2 h of presentation of children with fever and neutropenia and, on outcome, from all pediatric cancer patients presenting with fever and neutropenia from 1993 through 2001 in a retrospective single center cohort study. After univariate analyses a multivariate decision tree was constructed, and its performance was evaluated by cross-validation. RESULTS: Bacteremia was detected in 87 (24%) and Gram-negative bacteremia in 30 (8%) of 364 episodes of fever and neutropenia. At the predetermined sensitivity level, > or =95%, decision tree models reached cross-validated specificities of 37 and 43%, with negative predictive values of 96 and 99%, for bacteremia and Gram-negative bacteremia, respectively. Absence of a clinically or radiologically evident source of infection and previous episodes of fever and neutropenia were defined as two newly described factors associated with bacteremia. CONCLUSIONS: Based on this retrospective analysis, it appears that bacteremia can be predicted with clinically useful specificity at a high level of sensitivity, using clinical information available at presentation in pediatric cancer patients with fever and neutropenia.

Adolescent↗

Staphylococcus aureus bacteremia: recurrence and the impact of antibiotic treatment in a prospective multicenter study.

Staphylococcus aureus bacteremia is associated with substantial morbidity. Recurrence is common, but incidence and risk factors for recurrence are uncertain. The emergence of methicillin resistance and the ease of administering vancomycin, especially in patients who have renal insufficiency, have led to reliance on this drug with the assumption that it is as effective as beta-lactam antibiotics, an assumption that remains open to debate. We initiated a multicenter, prospective observational study in 6 university hospitals and enrolled 505 consecutive patients with S. aureus bacteremia. All patients were monitored for 6 months and patients with endocarditis were followed for 3 years. Recurrence was defined as return of S. aureus bacteremia after documentation of negative blood cultures and/or clinical improvement after completing a course of antistaphylococcal antibiotic therapy. All blood isolates taken from patients with recurrent bacteremia underwent pulsed-field gel electrophoresis testing. Recurrence was subclassified as reinfection (different pulsed-field gel electrophoresis patterns) or relapse (same pulsed-field gel electrophoresis pattern).Forty-two patients experienced 56 episodes of recurrence (79% were relapses and 21% were reinfection). Relapse occurred earlier than reinfection (median, 36 versus 99 d, p < 0.06). Risk factors for relapse of S. aureus bacteremia included valvular heart disease, cirrhosis of the liver, and deep-seated infection (including endocarditis). Nafcillin was superior to vancomycin in preventing bacteriologic failure (persistent bacteremia or relapse) for methicillin-susceptible S. aureus (MSSA) bacteremia. Failure to remove infected intravascular devices/catheters and vancomycin therapy were common factors in patients experiencing multiple (greater than 2) relapses. However, by multivariate analysis, only endocarditis and therapy with vancomycin (versus nafcillin) were significantly associated with relapse. Recurrences occurred in 9.4% of S. aureus bacteremias following antistaphylococcal therapy, and most were relapses. Duration of antistaphylococcal therapy was not associated with relapse, but type of antibiotic therapy was. Nafcillin was superior to vancomycin in efficacy in patients with MSSA bacteremia.

Adolescent↗

Short-term prognosis of community-acquired bacteremia in patients with liver cirrhosis or alcoholism: A population-based cohort study.

BACKGROUND: Liver cirrhosis is associated with an increased risk of infection and a poor prognosis, but the role of alcoholism in these outcomes is uncertain. This study looks at the short-term prognosis for bacteremia in patients with alcoholic liver cirrhosis, nonalcoholic liver cirrhosis, and alcoholism, compared with the prognosis for other bacteremia cases. METHODS: All patients who were hospitalized with their first community-acquired bacteremia in North Jutland County, Denmark, in the period 1992 to 2002 were retrieved from a population-based bacteremia registry. Denmark's Hospital Discharge Registry then allowed us to disaggregate these patients into the following groups: 47 patients with alcoholic liver cirrhosis, 19 with nonalcoholic liver cirrhosis, 190 with alcoholism, and a comparison group of 3,535 other bacteremia cases. Using logistic regression, we estimated odds ratios (ORs) for 30-day case fatality for the main study variable, adjusted for gender, age, focus of infection, and comorbidity. RESULTS: The case fatality rate (CFR) was 43% for patients with alcoholic liver cirrhosis, 32% for patients with nonalcoholic liver cirrhosis, 24% for patients with alcoholism, and 15% for other bacteremia patients. The adjusted OR estimates for patients with alcoholic liver cirrhosis, nonalcoholic liver cirrhosis, and alcoholism compared with other bacteremia cases were 6.3 (95% CI 3.3-11.7), 2.4 (95% CI 0.9-6.7), and 2.5 (95% CI 1.7-3.7), respectively. Focus of infection and group of bacteria did not noticeably affect the increased CFR. CONCLUSION: Liver cirrhosis and alcoholism were associated with a poor short-term prognosis for community-acquired bacteremia. Liver cirrhosis and alcoholism may have independent effects on the prognosis for patients with liver cirrhosis and bacteremia.

Adult↗

Bacteremia in patients with cirrhosis of the liver.

Infections are frequent in patients with liver cirrhosis, as their defenses against infectious agents are altered. But bacteremia occurring in cirrhotic patients has seldom been reported in the literature. From 1981 to 1986, we collected 197 cases with 228 episodes of bacteremia for this retrospective study. The incidence of bacteremia in cirrhotic patients was 8.8%; no significant difference was noted between cirrhotic patients with variant etiologies of HBV(+), HBV(-) and alcohol. But the incidence increased with the severity of the disease (1%, 4.8%, 17.1% in Child's A, B, C groups, respectively). Gram-negative bacteria were the predominant microorganisms of bacteremia (75.6%). Among them, Escherichia coli, Klebsiella pneumoniae and Aeromonas hydrophilia were the three most commonly detected microorganisms. Gram-positive bacterias were detected in 21.2% of patients with bacteremia, with predominance of the Streptococcus group and Staphylococcus aureus. In about 26.3% of cases the infectious sources were the same by bacteria cultures as from blood. The most common sources were spontaneous bacterial peritonitis, urinary tract infection, pneumonia and biliary tree infection. In cirrhotic patients with and without bacteremia, the mortality rate increased significantly in the bacteremia group (54.8% vs 23.2%, P less than 0.05). By Child's classification, the mortality of patients with classes B and C increased significantly after onset of bacteremia. There was no significant difference in mortality between bacteremic patients in the HBV(+), HBV(-) and alcohol groups. In conclusion, bacteremia is a severe complication of liver cirrhosis and a sign of a poor prognosis.

Bacteremia↗

Case-control analysis of endemic Serratia marcescens bacteremia in a neonatal intensive care unit.

BACKGROUND: Serratia marcescens is an opportunistic gram-negative rod which typically infects compromised hosts. OBJECTIVES: To identify risk factors, signs, and outcomes associated with non-epidemic S marcescens bacteremia in a neonatal intensive care unit (NICU). METHODS: The records of infants with S marcescens bacteremia while in the Yale-New Haven Hospital NICU from 1980-2004 were reviewed. A matched case-control study was performed by comparing each case of S marcescens to 2 uninfected controls and 2 cases of Escherichia coli bacteremia. RESULTS: Twenty-five sporadic cases of S marcescens bacteremia were identified. Eleven available isolates were determined to be different strains by pulse field gel electrophoresis. Infants with S marcescens bacteremia had median gestational age and birth weight of 28 weeks and 1235 grams, respectively. Compared to matched, uninfected controls, infants with S marcescens bacteremia were more likely to have had a central vascular catheter (OR = 4.33; 95% CI (1.41 to 13.36)) and surgery (OR = 5.67; 95% CI (1.81 to 17.37)), and had a higher overall mortality (44% vs 2%; OR = 38.50; 95% CI (4.57 to 324.47)). Compared to E coli matched controls, infants with S marcescens bacteremia had later onset of infection (median of 33 days of life vs 10; p<0.001), prolonged intubation (OR = 5.76; 95% CI (1.80 to 18.42)), and a higher rate of CVC (OR = 7.77; 95% CI (2.48 to 24.31)) use at the time of infection. A higher rate of meningitis (24% vs 7%; OR = 3.98; 95% CI (1.09 to 14.50)) was observed with S marcescens bacteremia compared to E coli. CONCLUSIONS: S marcescens bacteremia occurs sporadically in the NICU, primarily in premature infants requiring support apparatus late in their hospital course. Associated meningitis is common and mortality high.

Bacteremia↗

Predicting the risk of bacteremia in childen with fever and neutropenia.

PURPOSE: We sought to identify factors assessable at the time of admission for fever and neutropenia that predict bacteremia in children with cancer. PATIENTS AND METHODS: One hundred fifteen consecutive episodes of fever and absolute neutrophil count (ANC) less than 500/microliter in 72 children with cancer were studied prospectively to determine the risk of bacteremia using data assessable at the time of presentation. After exploratory analysis identified admission temperature and absolute monocyte count (AMoC) as the strongest predictive factors, recursive partitioning was used to determine cutpoints for these variables that resulted in discrimination between episodes associated with a lower or higher risk of bacteremia. RESULTS: There were 24 episodes of bacteremia (21% of episodes). Episodes were grouped using the cutpoints for AMoC and temperature: 17% were classified as low risk for bacteremia (AMoC > or = 100/microliter), 65% as intermediate risk (AMoC < 100/microliter and temperature < 39.0 degrees C), and 18% as high risk (AMoC < 100/microliter and temperature > or = 39.0 degrees C). No episodes classified as low risk were associated with bacteremia; 19% of intermediate-risk and 48% of high-risk episodes were associated with bacteremia. The odds ratio of bacteremia for the high-risk versus the intermediate-risk group is 4.4 (95% confidence interval, 1.6 to 12.9). The risk classification was validated using data from 57 different episodes of fever and neutropenia treated in the same hospital. CONCLUSION: Three levels of risk for bacteremia are defined using the AMoC and temperature at the time of admission for fever and neutropenia. Trials now should be conducted to test whether these factors may be used to assign some children to less intensive or outpatient antibiotic therapy at the time of presentation with fever and neutropenia.

Adolescent↗

Serotype prevalence of occult pneumococcal bacteremia.

OBJECTIVE: The licensure and use of a pneumococcal conjugate vaccine that is immunogenic in children who are younger than 2 years may affect the epidemiology of occult bacteremia. This study was conducted to determine the serotype prevalence of Streptococcus pneumoniae isolates from children with occult bacteremia and to document the proportion that would be covered by the recently licensed heptavalent pneumococcal conjugate vaccine. METHODS: A cohort of 5901 children who were 2 to 24 months of age and had a temperature of >/=39.0 degrees C evaluated with a blood culture at an urban tertiary care children's hospital emergency department was studied to determine the prevalence of S pneumoniae serotypes. Patients were excluded if their immune system was suppressed, they had a diagnosis of a focal infection, they were evaluated by lumbar puncture, they were admitted to the hospital, or they died during initial evaluation. Blood cultures were inoculated into pediatric blood culture bottles and processed using an automated carbon dioxide monitoring system. All pneumococcal isolates were serotyped on the basis of capsular swelling with type-specific antisera (Quellung reaction). RESULTS: The study population consisted of 5901 patients. The overall rate of occult bacteremia was 1.9% (95% confidence interval [CI]: 1.5-2.3). S pneumoniae accounted for 92 of 111 isolates (82.9%; 95% CI: 74.6-89.4) in children with occult bacteremia. Eight pneumococcal serotypes were represented: 6A (2%), 9V (6%), 19F (6%), 18C (8%), 4 (9%), 6B (13%), 23F (15%), and 14 (42%). Serotypes 14, 6B, and 23F accounted for 69.3% (95% CI: 58.6-78.7) of typed isolates. In the cohort, 97.7% (95% CI: 92-99.7) of isolated serotypes are represented in the newly licensed heptavalent pneumococcal conjugate vaccine. The single isolated serotype that would not have been covered by the currently licensed heptavalent pneumococcal conjugate vaccine was 6A. CONCLUSIONS: S pneumoniae accounts for the vast majority of bacterial pathogens in children with occult bacteremia. As indicated by the results of this study, the heptavalent pneumococcal conjugate vaccine may prevent the majority of occult pneumococcal bacteremia episodes. The 2 cases of bacteremia with a serotype that would not have been included in the vaccine both were due to serotype 6A. It has been noted that there is potential nonvaccine serotype and subgroup cross-protection (6A from 6B) afforded to children who are immunized with the heptavalent vaccine. The high potential efficacy of the heptavalent pneumococcal conjugate vaccine for strains that cause occult bacteremia in our population may have a profound effect on the treatment of children with fever without a source. There has been an alarming and rapid emergence of antibiotic-resistant pneumococcal strains. Less pressure to use broad-spectrum antibiotics, which in turn causes further antibiotic resistance, should result. Laboratory testing and hospitalization also should be reduced. The prevalence rates determined by this study may be used as baseline data for comparison of serotype rates of occult pneumococcal bacteremia after widespread use of the heptavalent vaccine.

Bacteremia↗

EPIBACDIAL: a multicenter prospective study of risk factors for bacteremia in chronic hemodialysis patients.

Bacteremic infections are a major cause of mortality and morbidity in chronic hemodialysis patients. New developments in managing these patients (erythropoietin therapy, nasal mupirocin, long-term implanted catheters, and synthetic membranes) may have altered the epidemiologic patterns of bacteremia in dialysis patients. This multicenter prospective cross-sectional study was carried out to determine the current incidence of and risk factors for bacteremia in chronic hemodialysis patients in France. A total of 988 adults on chronic hemodialysis for 1 mo or longer was followed up prospectively for 6 mo in 19 French dialysis units. The factors associated with the development of at least one bacteremic episode over 6 mo were determined using the multivariate Cox proportional hazards model. Staphylococcus aureus (n=20) and coagulase-negative staphylococci (n=15) were responsible for most of the 51 bacteremic episodes recorded. The incidence of bacteremia was 0.93 episode per 100 patient-months. Four risk factors for bacteremia were identified: (1) vascular access (catheter versus fistula: RR=7.6; 95% CI, 3.7 to 15.6); (2) history of bacteremia (> or =2 versus no previous episode: RR=7.3; 95% CI, 3.2 to 16.4); (3) immunosuppressive therapy (current versus no: RR=3.0; 95% CI, 1.0 to 6.1); and (4) corpuscular hemoglobin (per 1 g/dl increment: RR=0.7; 95% CI, 0.6 to 0.9). Catheters, especially long-term implanted catheters, were found to be the leading risk factor of bacteremia in chronic hemodialysis patients. There was a trend toward recurrence of bacteremia that was not associated with chronic staphylococcal nasal carriage. Synthetic membranes were not associated with a lower risk of bacteremia in this population of well dialyzed patients, but anemia linked to resistance to erythropoietin appeared to be a possible risk factor for bacteremia.

Adolescent↗