Clinical implications of penicillin and ceftriaxone resistance among children with pneumococcal bacteremia

Phenotypic and genotypic characterization of invasive Streptococcus pneumoniae clinical isolates

BACKGROUND

The emergence of infection caused by invasive penicillinnonsusceptible (PNS) and multidrug-resistant strains of Streptococcus pneumoniae has become a worldwide concern, necessitating the epidemiologic surveillance of such strains.

OBJECTIVES

One aim of this study was to identify clones of invasive PNS S pneumoniae among isolates in Riyadh, Saudi Arabia. The second aim was to compare these clones with international clones to track their spread in Saudi Arabia.

METHODS

The phenotypes of invasive isolates characterized as S pneumoniae were determined using susceptibility testing and serotyping (capsular test and E-test). The genotypes of PNS isolates were determined using random amplified polymorphic DNA analysis. The genetic relatedness of these local strains to the international widespread clones was investigated.

RESULTS

Of 296 S pneumoniae isolates identified using biochemical and culture characteristics, 89 (30.1%) were invasive. Susceptibility testing using the E-test revealed that 17 of the 89 invasive isolates (19.1%) were PNS. Most of the 89 isolates (89.9%) were resistant to sulfamethoxazole-trimethoprim; 32.6% and 23.6% of isolates were resistant to chloramphenicol and tetracycline, respectively. All of the isolates (100.0%) were fully susceptible to ceftriaxone and vancomycin. Capsular serotyping of the 89 isolates showed that 19A (18.0%), 613 (14.6%), 23F (13.5%), 9V (11.2%), 14 (6.7%), 19F (5.6%), and 18C (4.5%) were the most predominant serogroups/serotypes. The 17 PNS strains were confirmed on polymerase chain reaction to have penicillin resistance genes. Of these 17 strains, international clone 19A-a was the most predominant (41.2%), followed by 6B-a (17.6%), and 23F-a and 9V-a (each, 11.8%).

CONCLUSIONS

The present study identified the spread of the 4 most commonPNS S pneumoniae isolates (clones)-19A, 613, 23F, and 9V-to Riyadh, but identified no new clones among patients having invasive infection with S pneumoniae in Riyadh. This study emphasizes that international PNS clones have contributed to the prevalence and spread of PNS pneumococci among the clinical isolates in Saudi Arabia.

Impact of penicillin nonsusceptibility on clinical outcomes of patients with nonmeningeal Streptococcus pneumoniae bacteremia in the era of the 2008 clinical and laboratory standards institute penicillin breakpoints

To investigate the impact of penicillin nonsusceptibility on clinical outcomes of patients with nonmeningeal Streptococcus pneumoniae bacteremia (SPB), a retrospective cohort study was performed. The characteristics of 39 patients with penicillin-nonsusceptible SPB (PNSPB) were compared to those of a group of age- and sex-matched patients (n = 78) with penicillin-susceptible SPB (PSSPB). Susceptibility to penicillin was redetermined by using the revised Clinical and Laboratory Standards Institute (CLSI) penicillin breakpoints in CLSI document M100-S18. Although the PNSPB group tended to have more serious initial manifestations than the PSSPB group, the two groups did not differ significantly in terms of their 30-day mortality rates (30.8% versus 23.1%; P = 0.37) or the duration of hospital stay (median number of days, 14 versus 12; P = 0.89). Broad-spectrum antimicrobial agents, such as extended-spectrum cephalosporins, vancomycin, and carbapenem, were frequently used in both the PNSPB and PSSPB groups. Multivariate analysis revealed that ceftriaxone nonsusceptibility (adjusted odds ratio [aOR] = 4.88; 95% confidence interval [CI] = 1.07 to 22.27; P = 0.041) was one of the independent risk factors for 30-day mortality. Thus, when the 2008 CLSI penicillin breakpoints are applied and the current clinical practice of using wide-spectrum empirical antimicrobial agents is pursued, fatal outcomes in patients with nonmeningeal SPB that can be attributed to penicillin nonsusceptibility are likely to be rare. Further studies that examine the clinical impact of ceftriaxone nonsusceptibility in nonmningeal SPB may be warranted.

Bacteremia in children at the University Hospital in Riyadh, Saudi Arabia

BACKGROUND

Bacteremia is a major pediatric health care problem despite the availability of new modalities in the management of this disease. The aim of the present study was to determine the incidence and pattern of bacteremia in pediatric group at a tertiary hospital in Riyadh, SaudiArabia.

METHODS

This retrospective study was conducted at the Department of Pediatrics, College of Medicine, King Khalid University Hospital, Riyadh in the period of January 2003 to January 2005. Positive culture was found in 259 patients aged below 15 years with a total of 8244 admissions in the period.

RESULTS

The highest incidence of bacteremia was found in patients aged less than 1 year (57.9%), and the majority of patients (30.5%) were infants aged less than 1 month. Staphylococcus aureus was the most common isolated pathogen (18.7%). Prematurity was associated with 13.2% of the cases, and respiratory tract infection (10.1%) and fever (76.1%) were chief complaints.

CONCLUSIONS

Staphylococcus aureus is the most common isolated pathogen. The most common primary infections are respiratory tract infection and septic meningitis. Klebsiellapneumoniae and E. coli are the most common isolated Gram-negative organisms.

Bacteremia in children at a regional hospital in Trinidad

OBJECTIVE

The objective of this study was to provide a Trinidadian perspective on pediatric community-acquired and hospital-acquired bacteremia via the documentation of common etiologic agents, antimicrobial profiles of the isolated pathogens, and patient outcome.

METHODS

This was a six-year retrospective study of children with bacteremia admitted to the pediatric wards of the San Fernando General Hospital, Trinidad.

RESULTS

Seven hundred and four episodes of pediatric bacteremia were reviewed during the six-year study period. The predominant isolate was Staphylococcus aureus (23.9%), followed by Pseudomonas aeruginosa (15.5%), Klebsiella pneumoniae (12.5%), and Enterobacter spp (11.1%). The remaining isolates each accounted for less than 10% of total isolates. The mortality rate was highest for P. aeruginosa (39.4%), Streptococcus pneumoniae (22.5%), and Escherichia coli (19.2%). Of the six cases due to Neisseria meningitidis, only two survived. The overall mortality rate for the study period was 15.1%, but varied considerably according to age. All deaths due to P. aeruginosa and E. coli occurred in neonates. Almost 90% and about half of all S. aureus were resistant to ampicillin and erythromycin, respectively; nineteen (11.3%) were methicillin-resistant. More than 95% of K. pneumoniae and more than 87% of Haemophilus influenzae were resistant to ampicillin. Group B streptococci were fully susceptible to ampicillin and amoxicillin-clavulanic acid, but showed >90% and >70% resistance to tetracycline and trimethoprim-sulfamethoxazole, respectively. Of the 40 strains of S. pneumoniae isolated, 10.0% had a minimum inhibitory concentration (MIC) >or=4 microg/mL (resistance) and 12.5% had a MIC=2.0 microg/mL (intermediate resistance) to ceftriaxone, while 7.5% showed intermediate resistance (MIC between 0.12 and 1 microg/mL) and 25.0% showed resistance (MIC >or=2 microg/mL) to penicillin.

CONCLUSION

The bacteremia rate was found to be 8.4% among hospitalized children suspected of having sepsis and from whom a blood culture was positive. Bacteremia was also associated with a high mortality rate of 15.1%. An unusually high level of bacteremia with Gram-negative enteric bacteria was seen, which might indicate cross infection and reflect a breakdown in infection control measures. Relatively high-level resistance of S. pneumoniae to penicillin and ceftriaxone was not seen, even though the overall prevalence of resistance to other antibiotics among other pathogens was relatively low. The drugs that showed the greatest efficacy were imipenem, gentamicin, ciprofloxacin, and the cephalosporins ceftazidime and ceftriaxone.

Active surveillance of Streptococcus pneumoniae bacteremia in Italian children

There are few data published regarding the incidence of Streptococcus pneumoniae bacteremia in Italian children. A 14-month surveillance study was conducted in 10 paediatric hospitals to investigate the rate of Sp bacteremia in children aged less than 5 years. The serotype prevalence and antimicrobial susceptibility of isolates were determined. A total of 55 Sp isolates were obtained from 4576 blood cultures (incidence rate, 1.2%). In order of frequency, the most common serotypes were 14, 23F, 19F, 9V, 1. Serotypes in the 7-valent conjugate pneumococcal vaccine (4, 6B, 9V, 14, 18C, 19F, 23F) accounted for 70% of isolates under 2 years of age, and 58% in the interval between 2 and 5 years of age.

Nosocomial bloodstream infections caused by Streptococcus pneumoniae

A retrospective study of Streptococcus pneumoniae bacteraemia among adult patients in two large teaching hospitals in Spain identified 108 (10.6%) of 1,020 episodes as nosocomial pneumococcal bloodstream infections (NPBIs). Seventy-seven clinical records with sufficient data were available for analysis. The interval between admission and a positive blood culture was 3--135 days (median 17 days; interquartile range 8--27). The main underlying and predisposing conditions for NPBI were malignancy (31%), chronic obstructive pulmonary disease (28.6%), heart failure (16.9%), chronic renal failure (15.6%), liver cirrhosis (13%) and infection with human immunodeficiency virus (13%). Overall, 31.2% of patients developed severe sepsis, 11.7% septic shock, and 3.9% multi-organ failure. The main portals of entry were pneumonia (70.1%), meningitis (5.2%) and primary peritonitis (5.2%). Of the responsible serogroups, 78% were included in the 23-valent polysaccharide vaccine. Thirty-five (45.5%) patients died, with death considered to be related to the NPBI in 21 (27.3%) cases. Following multivariate analysis, factors that independently predicted death after adjusting for age were: ultimately fatal underlying disease (OR, 8.9; 95% CI, 0.8--94.3; p<0.001); rapidly fatal underlying disease (OR, 15.0; 95% CI, 2.8--81.3; p<0.001); heart failure (OR, 8.11; 95% CI, 1.1--60.8; p<0.03); inadequate empirical therapy (OR, 10.6; 95% CI, 1.2--97; p<0.003); a severe sepsis score (OR, 9.5; 95% CI, 1.9--47.0; p<0.001); and septic shock or multi-organ failure (OR, 63.7; 95% CI, 4.9--820.7; p<0.001). Adequate empirical therapy was an independent protective factor (OR, 0.05; 95% CI, 0.04--0.58; p<0.005), but the use of more than one antimicrobial agent was not.

Penicillin resistance and serotypes/serogroups of Streptococcus pneumoniae in nasopharyngeal carrier children younger than 2 years in Lima, Peru

The purpose of this study was to determine the carriage rate, susceptibility pattern, and serotype distribution of Streptococcus pneumoniae in the nasopharynx of children younger than 2 years old in Lima, Peru. A total of 666 children were evaluated during 3 periods, 1997, 2001, and 2003. The overall pneumococcal carrier rate was 41%. Reduced susceptibility to penicillin was found in 5% (4/75) of isolates in 1997, 20% (15/75) in 2001, and 37% (40/109) in 2003. Reduced susceptibility to ceftriaxone was found in 12% of isolates in 2003. Serogroups 6, 19, 23, 15, and 14 accounted for 68% of all the isolates and for 81% of the penicillin-nonsusceptible strains. Only 65% of the isolated strains had serogroups found in the 7-valent conjugate pneumococcal vaccine. This highlights the importance of regional surveillance studies for effective vaccine strategies and treatment protocols.

Reference group choice and antibiotic resistance outcomes

Two types of cohort studies examining patients infected with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) were contrasted, using different reference groups. Cases were compared to uninfected patients and patients infected with the corresponding, susceptible organism. VRE and MRSA were associated with adverse outcomes. The effect was greater when uninfected control patients were used.

Azithromycin compared with beta-lactam antibiotic treatment failures in pneumococcal infections of children

OBJECTIVE

To determine whether treatment failures occurred more commonly with azithromycin than with beta-lactam antibiotics in children who developed invasive pneumococcal disease within 30 days of receiving prior antimicrobial therapy.

METHODS

Retrospective review of medical records of children evaluated at Texas Children's Hospital between 1996 and 2002 who had received antimicrobials (azithromycin or a beta-lactam antibiotic) and developed invasive pneumococcal disease within 30 days. Treatment failure was defined as invasive pneumococcal infection that occurred while taking antimicrobials or within 3 days of stopping azithromycin treatment or 1 day of stopping beta-lactam treatment. Penicillin and azithromycin susceptibilities were determined and categorized according to National Committee for Clinical Laboratory Standards guidelines.

RESULTS

We identified 21 and 33 children with similar demographic features who had developed invasive pneumococcal disease within 1 month of receiving azithromycin or a beta-lactam antibiotic, respectively. Eleven (52%) children in the azithromycin group and 11 (33%) in the beta-lactam group met the definition for treatment failures (P = 0.34). Eight treatment failures while receiving azithromycin were caused by pneumococci with the macrolide-resistant (M) phenotype, 2 with the macrolide-, lincosamide- and streptogramin B-resistant (MLSB) phenotype and 1 by a macrolide-susceptible organism. In the beta-lactam group 7 had a penicillin-resistant isolate, 3 had an intermediately susceptible isolate and 1 had a susceptible isolate.

CONCLUSIONS

Our study suggests that treatment failures among patients who developed invasive disease within 30 days of receiving an antimicrobial occur as frequently in patients who receive beta-lactam antibiotics as in those who receive azithromycin. Furthermore macrolide resistant organisms are not more likely to be recovered after a macrolide treatment failure than a penicillin-nonsusceptible isolate being recovered after a beta-lactam treatment failure (P = 1.0).

Pneumococcal bacteremia in a single center in Argentina

OBJECTIVE

To determine the clinical and microbiologic characteristics of pneumococcal bacteremia at Sanatorio Mitre, Buenos Aires, Argentina.

METHODS

One-hundred-and-seven episodes of pneumococcal bacteremia were prospectively analyzed from 1993 to 1998. Demographics, clinical and microbiological variables were studied.

RESULTS

Eighty-one patients (76%) were adults and 26 children (24%). Most cases (98%) were acquired in the community. Seventy-nine patients (74%) had at least one underlying condition. The primary source of bacteremia was found in 91 patients (85%), the lungs being the most common source. Streptococcus pneumoniae was isolated from one sterile site other than the primary focus in 25 patients (23%). Eighty-five (79%) of the Streptococcus pneumoniae were susceptible to penicillin and 22 (21%) showed intermediate or high resistance to penicillin and 2% were additionally resistant to ceftriaxone. Initial antimicrobial therapy was appropriate in 95% of the cases. The overall mortality was 21%, however adults admitted to the intensive care unit (ICU) had higher mortality (81%). No patients under 14 years old died. Multivariate analysis showed that age and recovery of the organisms from a sterile site other than the primary focus were statistically significant predictors of mortality.

CONCLUSION

Bacteremic pneumococcal infections continue to be an important worldwide problem causing morbidity and high mortality despite supportive care and appropriate antimicrobial therapy.

Approach to the febrile child: A challenge bridging the gap between the literature and clinical practice

The approach to the febrile child is always concerning for any physician despite the fact that most fevers are viral in origin. However, in rare cases, a missed bacterial infection can have serious consequences. How can fevers of viral origin be differentiated from those of bacterial origin? Do all febrile children with no obvious infection site need a blood culture? Should antibiotics be administered before the results of the blood culture have been received? In the past 30 years, there has been an overabundance of recommendations, advice, opinions and suggested treatments on this subject. The purpose of this review is to present the evidence that is known at this time concerning the management of the febrile child and to present one approach used in a large urban paediatric emergency department.

The effect of cephalosporin resistance on mortality in adult patients with nonmeningeal systemic pneumococcal infections

PURPOSE

To evaluate the clinical relevance of cephalosporin (ceftriaxone/cefotaxime) resistance among patients with nonmeningeal systemic pneumococcal infection.

SUBJECTS AND METHODS

From January 1994 to October 2000, we prospectively studied 522 episodes of nonmeningeal systemic pneumococcal infections (448 pneumonias) in 499 adults who were treated according to hospital guidelines. In vitro antibiotic susceptibility, as the minimum inhibitory concentration (MIC), was determined by microdilution method. The MIC methods and breakpoints (cutoffs) were established by the National Committee for Clinical Laboratory Standards.

RESULTS

Of the 522 pneumococcal strains, 413 strains (79%) were susceptible to ceftriaxone/cefotaxime, MIC < or =0.5 microg/mL; 79 (15%) were intermediate, MIC = 1 microg/mL; and 30 (6%) were resistant, MIC = 2 microg/mL. After adjusting for several variables, including pneumococcal serogroups/serotypes, infections due to nonsusceptible (intermediate and resistant) pneumococcal strains were independently associated with prior antibiotic therapy, with an odds ratio of 5.9 (95% confidence interval: 2.6 to 13.6). Thirty-day mortality among the 185 patients who were treated with ceftriaxone (1 g/d) or cefotaxime (1.5 g every 8 hours) did not differ by cephalosporin susceptibility: 18% (26/148) among those with susceptible organisms, 13% (3/24) with intermediate organisms, and 15% (2/13) in resistant cases (P = 0.81).

CONCLUSION

Ceftriaxone or cefotaxime were effective in treating patients with nonmeningeal systemic pneumococcal infections caused by strains with MIC < or =2 microg/mL. These results support the newly established ceftriaxone/cefotaxime MIC breakpoints (cutoffs) for nonmeningeal pneumococcal infections.

Clinical aspects and cost of invasive Streptococcus pneumoniae infections in children: resistant vs. susceptible strains

Invasive Streptococcus pneumoniae infections in children are associated with serious consequences in terms of morbidity and mortality. The main objective of the study was to determine if invasive infections caused by penicillin-resistant Streptococcus pneumoniae (PRSP) differed in clinical presentation, outcome, risk factors, or cost from those caused by penicillin-susceptible strains (PSSP) in children. All patients aged 18 or less with invasive Streptococcus pneumoniae infections admitted to two teaching hospitals in Montreal between 1989 and 1998 were included in the study. We present a case-control study in which for each index case of PRSP, 3 controls with PSSP infections were matched for age, sex, and site of infection. One hundred and forty-four patients were included in the analysis (36 cases, 108 controls). There was no difference between the two groups in terms of initial clinical presentation (vital signs, laboratory results) or total length of stay. Mortality was 2.7% in both groups. Hospital antibiotic cost was higher in the PRSP group (211 Canadian dollars (CAD) vs. 74 CAD; P=0.02). Antibiotic consumption in the preceding month was significantly associated with PRSP infection. Underlying diseases or day-care attendance were not shown to be significant risk factors for acquiring invasive PRSP infection. There were no differences between invasive infections caused by PRSP and PSSP in terms of clinical presentation, morbidity or mortality in a paediatric population.

Management of febrile children in the age of the conjugate pneumococcal vaccine: a cost-effectiveness analysis

OBJECTIVES

The optimal practice management of highly febrile 3- to 36-month-old children without a focal source has been controversial. The recent release of a conjugate pneumococcal vaccine may reduce the rate of occult bacteremia and alter the utility of empiric testing and treatment. The objective of this study was to determine the cost-effectiveness of 6 different management strategies of febrile 3- to 36-month-old children at current and declining rates of occult pneumococcal bacteremia.

METHODS

A cost-effectiveness (CE) analysis was performed to compare the strategies of "no work-up," "clinical judgment," "blood culture," "blood culture + treatment," "complete blood count (CBC) + selective blood culture and treatment," and "CBC and blood culture + selective treatment." A hypothetical cohort of 100 000 children who were 3 to 36 months of age and had a fever of >/=39 degrees C and no source of infection was modeled for each strategy. Our main outcome measures were cases of meningitis prevented, life-years saved compared with "no work-up," total cost (1999 dollars), and incremental CE ratios.

RESULTS

When compared with "no work-up," the strategy of "CBC + selective blood culture and treatment" using a white blood cell (WBC) cutoff of 15 x 10(9)/L prevents 48 cases of meningitis, saves 86 life-years per 100 000 patients, and is less costly at the current rate of bacteremia (1.5%). Using the strategy of "CBC + selective blood culture and treatment" with a lower WBC cutoff of 10 x 10(9)/L costs an additional $72 300 per life-year saved. If the rate of bacteremia declines to 0.5%, then the incremental CE ratio of "clinical judgment" compared with "no work-up" is $38 000 per life-year saved; however, strategies that include empiric testing or treatment result in CE ratios greater than $300 000 per life-year saved.

CONCLUSIONS

"CBC + selective blood culture and treatment" using a WBC cutoff of 15 x 10(9)/L is cost-effective at the current rate of pneumococcal bacteremia. If the rate of occult bacteremia falls below 0.5% with widespread use of the conjugate pneumococcal vaccine, then strategies that use empiric testing and treatment should be eliminated.

Outcome of invasive infections outside the central nervous system caused by Streptococcus pneumoniae isolates nonsusceptible to ceftriazone in children treated with beta-lactam antibiotics

OBJECTIVE

To determine the outcome of children treated primarily with beta-lactam antibiotics for a systemic infection outside the central nervous system (CNS) caused by isolates of Streptococcus pneumoniae nonsusceptible to ceftriaxone (MIC > or = 1.0 microg/ml).

DESIGN

Retrospective review of the medical records of children identified prospectively with invasive infections outside of the CNS caused by isolates of S. pneumoniae that were not susceptible to ceftriaxone between September, 1993, and August, 1999. A subset of this group treated primarily with beta-lactam antibiotics was analyzed for outcome.

PATIENTS

Infants and children with pneumococcal infections cared for at eight children's hospitals.

RESULTS

Among 2,100 patients with invasive infections outside the CNS caused by S. pneumoniae, 166 had isolates not susceptible to ceftriaxone. One hundred patients treated primarily with beta-lactam antibiotics were identified. From this group 71 and 14 children had bacteremia alone or with pneumonia, respectively, caused by strains with an MIC of 1.0 microg/ml. Bacteremia or pneumonia caused by isolates with a ceftriaxone MIC > or = 2.0 microg/ml occurred in 6 and 5 children, respectively. Three children with septic arthritis and 1 with cellulitis had infections caused by strains with an MIC to ceftriaxone of 1.0 microg/ml. Most were treated with parenteral ceftriaxone, cefotaxime or cefuroxime for one or more doses followed by an oral antibiotic. All but one child were successfully treated. The failure occurred in a child with severe combined immune deficiency and bacteremia (MIC = 1.0 microg/ml) who remained febrile after a single dose of ceftriaxone followed by 12 days of cefprozil.

CONCLUSION

Ceftriaxone, cefotaxime or cefuroxime are adequate to treat invasive infections outside the CNS caused by pneumococcal isolates with MICs up to 2.0 microg/ml, a concentration currently considered resistant for these antibiotics by National Committee for Clinical Laboratory Standards breakpoints.

Pneumococcal conjugate vaccine

Pneumococcal infections account for a significant proportion of bacterial infections in infants and children. The growing threat from pneumococci resistant to penicillin and other antimicrobials has led to increased pressure for the development of an effective vaccine. The only vaccine available until recently, a purified polysaccharide vaccine, is limited in that it fails to induce adequate and long-lasting immunity in infants under 2 years of age, the age group most at risk from this disease. Polysaccharide antigens conjugated to certain proteins induce effective immunity with a rapid response to subsequent infection or antigen challenge. The success of the protein-conjugated haemophilus influenzae vaccine supports the strategy of protein-conjugated polysaccharide vaccines. Currently, published trials of conjugated pneumococcal vaccines have shown the effectiveness and safety of these vaccines. Conjugate vaccines also provide protection against otitis media and may eliminate nasopharyngeal carriage of this organism. Widespread use of this vaccine is both cost effective and safe.

Two-year surveillance of antibiotic resistance in Streptococcus pneumoniae in four African cities

Worldwide spread of antibiotic resistance in Streptococcus pneumoniae is a major problem. However, data from West and North African countries are scarce. To study the level of resistance and compare the situations in different cities, a prospective study was conducted in Abidjan (Ivory Coast), Casablanca (Morocco), Dakar (Senegal), and Tunis (Tunisia), from 1996 to 1997. The resistances to eight antibiotics of 375 isolates were studied by E test, and the results were interpreted using the breakpoints recommended by the National Committee for Clinical Laboratory Standards. Overall, 30.4% of the isolates were nonsusceptible to penicillin G (25.6% were intermediate and 4.8% were resistant). Amoxicillin (96.3% were susceptible) and parenteral third-generation cephalosporins (92.7%) were highly active. Resistance to chloramphenicol was detected in 8.6% of the isolates. High levels of resistance were noted for erythromycin (28%), tetracycline (38.3%), and cotrimoxazole (36.4%). Resistance to rifampin was rare (2.1%). There were significant differences in resistance rates between individual countries. Multiple resistance was more frequent in penicillin-nonsusceptible isolates than in penicillin-susceptible isolates. Recommendations for treatment could be generated from these results in each participating country.

Management of fever without source in infants and children

Twenty percent of febrile children have fever without an apparent source of infection after history and physical examination. Of these, a small proportion may have an occult bacterial infection, including bacteremia, urinary tract infection (UTI), occult pneumonia, or, rarely, early bacterial meningitis. Febrile infants and young children have, by tradition, been arbitrarily assigned to different management strategies by age group: neonates (birth to 28 days), young infants (29 to 90 days), and older infants and young children (3 to 36 months). Infants younger than 3 months are often managed by using low-risk criteria, such as the Rochester Criteria or Philadelphia Criteria. The purpose of these criteria is to reduce the number of infants hospitalized unnecessarily and to identify infants who may be managed as outpatients by using clinical and laboratory criteria. In children with fever without source (FWS), occult UTIs occur in 3% to 4% of boys younger than 1 year and 8% to 9% of girls younger than 2 years of age. Most UTIs in boys occur in those who are uncircumcised. Occult pneumococcal bacteremia occurs in approximately 3% of children younger than 3 years with FWS with a temperature of 39.0 degrees C (102.2 degrees F) or greater and in approximately 10% of children with FWS with a temperature of 39.5 degrees C (103.1 degrees F) or greater and a WBC count of 15, 000/mm(3) or greater. The risk of a child with occult pneumococcal bacteremia later having meningitis is approximately 3%. The new conjugate pneumococcal vaccine (7 serogroups) has an efficacy of 90% for reducing invasive infections of Streptococcus pneumoniae. The widespread use of this vaccine will make the use of WBC counts and blood cultures and empiric antibiotic treatment of children with FWS who have received this vaccine obsolete.

Fever without apparent source on clinical examination, lower respiratory infections in children, and enterovirus infections

This section focuses on issues in infectious disease that are commonly encountered in pediatric office practice. McCarthy discusses recent literature regarding the evaluation and management of acute fevers without apparent source on clinical examination in infants and children and the evaluation of children with prolonged fevers of unknown origin. Klig reviews recent literature about lower respiratory tract infection in children. Finally, Kennedy and Kahn discuss recent developments in infectious diseases pertinent to office practice.