Risk factors and course of illness among children with invasive penicillin-resistant Streptococcus pneumoniae. The Streptococcus pneumoniae Working Group

[Regional System for Vaccines (SIREVA), laboratory surveillance and vaccine development for Streptococcus pneumoniae: bibliometric analysis, 1993-2019]

Objetivo.

Medir a través del análisis bibliométrico la productividad, la visibilidad y el impacto del Sistema Regional de Vacunas (SIREVA, un proyecto de la Organización Panamericana de la Salud) en sus dos componentes, la vigilancia por laboratorio y el desarrollo de vacunas.

Métodos.

Se recuperaron de Scopus las publicaciones correspondientes a vigilancia por laboratorio y desarrollo de vacunas con sus referencias y citas y se aplicó la herramienta para obtener los indicadores bibliométricos. Se utilizó VOSviewer^® 1.6.13 para visualizar las redes de coautoría por país y autores, y para realizar un análisis de coocurrencia de términos incluidos en los títulos y resúmenes de las publicaciones.

Resultados.

Cumplieron los criterios establecidos para vigilancia por laboratorio y desarrollo de vacunas 173 y 128 publicaciones, respectivamente. Diez países de la Región fueron responsables de 90,8% de las publicaciones sobre vigilancia por laboratorio y 8 países de todas las publicaciones sobre desarrollo de vacunas. Las diez publicaciones más citadas sobre vigilancia por laboratorio y sobre desarrollo de vacunas estaban incluidas en 855 y 503 artículos, respectivamente; los principales autores se encontraban en Alemania, Australia, Bélgica, Brasil, China, Estados Unidos de América y el Reino Unido. La construcción y visualización de redes por coautorías de autores y países, y la coocurrencia de términos mostraron el trabajo en red y la colaboración intrarregional, así como permitieron hacer seguimiento a las diversas áreas de estudio y su evolución en el tiempo.

Conclusiones.

El análisis bibliométrico permitió documentar de manera objetiva la productividad y visibilidad del Sistema Regional de Vacunas para Streptococcus pneumoniae en la Región.

Risk factors associated with Streptococcus pneumonia carriage in children under five years old with acute respiratory infection in Niger

Introduction

Streptococcus pneumonia is a leading cause of bacterial pneumonia, meningitis and sepsis in children, and pneumococcal carriage is an important source of horizontal spread of these pathogens within the community.

Methods

A questionnaire was addressed to parents for the collection of sociodemographic and medical information. Nasopharyngeal swabbing was processed using a molecular method. We used logistic regression models to examine independent associations between pneumococcal carriage and potential risk factors. All associations with a p-value of < 0.25 in the bivariate regression analyses were subsequently entered in the multivariate regression model.

Results

A total of 637 children aged 1 to 59 months admitted for acute respiratory infection were included. The rate of respiratory virus carriage was 76%, whereas that of bacteria was 47% and that of bacteria-virus co-colonization was 42%. A bivariate analysis showed that carriage was not related to gender, father's or mother's education level, father's occupation, type of housing or lighting, or passive exposure to cigarette smoking in the house. It was also not linked to complete vaccination with PCV-13 or PPSV-23 and antibiotic treatment prior to hospitalization. A multivariate analysis showed that carriage was related to age greater than 3 months, maternal occupation, house flooring type, and co-colonization of another bacterium and virus.

Conclusion

These results can be helpful to understand the dynamics of pneumococcal nasopharyngeal colonization; they confirm the interest of vaccinating infants before the age of 3 months with appropriate vaccine to prevent spread nasopharyngeal colonization and pneumococcal diseases in children.

Prior antibiotic use and acquisition of multidrug-resistant organisms in hospitalized children: A systematic review

Objective:

Multidrug-resistant organisms (MDROs) cause ~5%–10% of infections in hospitalized children, leading to an increased risk of death, prolonged hospitalization, and additional costs. Antibiotic exposure is considered a driving factor of MDRO acquisition; however, consensus regarding the impact of antibiotic factors, especially in children, is lacking. We conducted a systematic review to examine the relationship between antibiotic use and subsequent healthcare-associated infection or colonization with an MDRO in children.

Design:

Systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline.

Methods:

We searched PubMed and Embase for all English, peer-reviewed original research studies published before September 2018. Included studies evaluated hospitalized children, antibiotic use as an exposure, and bacterial MDRO as an outcome.

Results:

Of the 535 studies initially identified, 29 met the inclusion criteria. Overall, a positive association was identified in most studies evaluating a specific antibiotic exposure (17 of 21, 81%), duration of antibiotics (9 of 12, 75%), and number of antibiotics received (2 of 3, 67%). Those studies that evaluated any antibiotic exposure had mixed results (5 of 10, 50%). Study sites, populations, and definitions of antibiotic use and MDROs varied widely.

Conclusions:

Published studies evaluating this relationship are limited and are of mixed quality. Limitations include observation bias in recall of antibiotic exposure, variations in case definitions, and lack of evaluation of antibiotic dosing and appropriateness. Additional studies exploring the impact of antibiotic use and MDRO acquisition may be needed to develop effective antibiotic stewardship programs for hospitalized children.

The Impact of Prior Antibiotic Therapy on Outcomes in Children Hospitalized for Community-Acquired Pneumonia

Here, we review current available literature regarding the effect of prior antibiotic treatment on outcomes of children hospitalized for community-acquired pneumonia (CAP). To date, no prospective trial has reported information regarding morbidity or mortality in this group of patients. Retrospective studies have provided evidence for the advantage of treatment with broad-spectrum antibiotics in children who failed prior antibiotic therapy. We discuss the changing epidemiology of CAP in the post PCV13 and Hib vaccines era and its relevance to the outcome of pediatric patients hospitalized for CAP. Current studies still report Streptococcus pneumoniae as the most common typical bacterial causative agent in pediatric CAP. However, in children who fail to respond to guideline directed antibiotic therapy, a non-pneumococcal, possibly one of several β-lactam resistant causative bacterial agents should be considered thus clarifying the advantage for broad-spectrum empirical antibiotic treatment in this group of patients.

Antibiotic treatment for children hospitalized with community-acquired pneumonia after oral therapy

OBJECTIVE

To compare the outcome of treatment with narrow spectrum versus broad spectrum antibiotics in children hospitalized with community-acquired pneumonia (CAP) who received oral antibiotic treatment prior to their hospitalization.

DESIGN, SETTING, AND PATIENTS

A review of all previously healthy children from 3 months to 18 years with non-complicated CAP who received an oral antibiotic course in the community and were admitted from 2003 to 2008 to our pediatric departments.

MAIN OUTCOME MEASURES

Clinical course and outcome parameters were compared for treatment with narrow and broad spectrum antibiotics.

RESULTS

Of the 337 children admitted with non-complicated CAP after an oral antibiotic treatment course in the community, 235 were treated with broad spectrum, and 102 with narrow spectrum antibiotics. The two groups were similar regarding age, sex, days of fever prior to admission, type of preadmission oral antibiotic treatment, and laboratory indices at admission (P > 0.1). The broad spectrum-treated group had significantly better outcomes in terms of number of febrile days (1.2 ± 1.1 vs. 1.7 ± 1.6, P < 0.001), number of days treated with intravenous antibiotics (3.1 ± 1.3 vs. 3.9 ± 2.0, P < 0.001), and days of hospitalization (3.5 ± 1.5 vs. 4.2 ± 2.0, P < 0.001). The odds ratio for remaining hospitalized at 72 hr and 7 days was significantly higher for the narrow spectrum group (2.0 and 5.5 respectively, P < 0.05).

CONCLUSIONS

In previously healthy children hospitalized with CAP after oral antibiotic treatment in the community treatment with broad spectrum antibiotics showed better outcome. Prospective studies are needed for appropriate recommendation.

High prevalence of antibiotic resistance in nasopharyngeal bacterial isolates from healthy children in rural Uganda: A cross-sectional study

BACKGROUND

In Uganda, the main causes of death in children under 5 years of age are malaria and pneumonia--often due to delayed diagnosis and treatment. In preparation for a community case management intervention for pneumonia and malaria, the bacterial composition of the nasopharyngeal flora and its in vitro resistance were determined in children aged five or under to establish baseline resistance to commonly used antibiotics.

METHODS

In a population-based survey in April 2008, nasopharyngeal specimens were collected from 152 randomly selected healthy children under 5 years of age in the Iganga/Mayuge Health and Demographic Surveillance Site (HDSS). Medical history and prior treatment were recorded. Demographic characteristics and risk factors for carriage of resistant strains were obtained from the HDSS census. Bacteria were isolated and analysed for antibiotic susceptibility using disk diffusion and E test.

RESULTS

Streptococcus pneumoniae (S. pneumoniae) carriage was 58.6%, and, while most (80.9%) isolates had intermediate resistance to penicillin, none was highly resistant. Whereas no isolate was resistant to erythromycin, 98.9% were resistant to trimethoprim-sulphamethoxazole (co-trimoxazole).

CONCLUSIONS

In vitro resistance in S. pneumoniae to co-trimoxazole treatment was high, and the majority of isolates had intermediate resistance to penicillin. To inform treatment policies on the clinical efficacy of current treatment protocols for pneumonia in health facilities and at the community level, routine surveillance of resistance in pneumonia pathogens is needed as well as research on treatment efficacy in cases with resistant strains. Improved clinical algorithms and diagnostics for pneumonia should be developed.

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

History of antibiotics. From salvarsan to cephalosporins

Infections have represented for a long time the leading cause of death in humans. During the 19th century, pneumonia, tuberculosis, diarrhea and diphtheria were considered the main causes of death in children and adults. Only in the late 19th century did it become possible to correlate the existence of microscopic pathogens with the development of various diseases. Within a few years the introduction of antiseptic procedures had begun to reduce mortality due to postsurgical infections. Sanitation and hygiene played a significant role in the reduction of the mortality due to several infectious diseases. The introduction of the first compounds with antimicrobial activity succeeded in conquering many diseases. In this review we analyzed, from a historical perspective, the development of antibiotics and the circumstances that led to their discovery. The first compound with antimicrobial activity was introduced in 1911 by Erlich. He focused his research activity on the discovery of a "magic bullet" to treat syphilis. Afterwards, Foley and colleagues brought penicillin to the forefront. Streptomycin represents the first drug discovered for the treatment of tuberculosis, and its development included the first use of clinical trials. Finally, with the development of cephalosporins, the introduction of new antimicrobial compounds with broad activity against gram-positive and also some gram-negative bacteria began.

A challenge to appropriate antibiotic use in children with respiratory infections: a 5-year single-institution experience

BACKGROUND

We have studied the rate of emergence of antibiotic-resistant Streptococcus pneumoniae (S. pneumoniae) and Haemophilus influenzae (H. influenzae) and the subsequent antibiotic use in host patients of those isolates at the Department of Pediatrics, Soma General Hospital, Fukushima. Moreover, we carried out several studies investigating the risks and benefits of antibiotic-free treatment for children with respiratory infections. In this report, we summarize our research and suggest better treatment options for pediatric patients with respiratory infections.

METHODS

We investigated the necessity of antibiotic use in the treatment of pediatric inpatients with respiratory syncytial virus (RSV) infection, and tested our hypothesis that antibiotic-free treatment for common cold will reduce the number of resistant S. pneumoniae strains in the pediatric nasopharynx. Therefore, we restricted prescribing antibiotics for pediatric patients with respiratory infections. The rates of resistant S. pneumoniae and H. influenzae and the medication history of the host patients before and after the intervention were compared.

RESULTS

We found that most of the RSV-infected patients recovered without antibiotic treatment, and that the antibiotic-free treatment inhibited the emergence of antibiotic-resistant strains. The rate of penicillin-resistant S. pneumoniae decreased but the rate of ampicillin-resistant H. influenzae did not change significantly during the study.

CONCLUSION

We concluded that patients with respiratory infections can be treated without antibiotics, under careful examination and observation. Continued monitoring of such new interventions as well as recommending their use to other caregivers and physicians will help inhibit the spread of resistant strains.

Non-antibiotic treatment for pediatric outpatients with common cold inhibits the emergence of drug resistant pneumococci

The occurrence of drug resistant Streptococcus pneurmoniae (S. pneumoniae) is very high in Japan. Unnecessary use of antibiotics had been thought to cause this problem but previous studies had not clearly showed that the decreasing rate of antibiotic use had been related to the reduction of the prevalence of resistant strains. In this study, we tried to prove that non-antibiotic treatment for common cold would reduce the antibiotic resistant S. pneumoniae in nasopharynx in children. Forty-five children with the common cold were randomly selected from pediatric patients who had taken antibiotics within the past three months. We collected nasopharyngeal swabs from all of the participants and once again after a period of 2 to 3 months without using any antibiotics. Twenty-four of these patients had the S. pneumoniae strains isolated. Then these strains were undergone a susceptibility test and drug-resistant gene detection. The susceptibility test reveled that patients with penicillin-resistant strains decreased from 17 to 7 (p < 0.01). The test also reveled that the decreased number of patients had strains that were resistant to cefditren. The gene detection revealed that none of the patients acquired a higher resistance to penicillin. Our study suggests that the treatment without antibiotics reduces the drug-resistant S. pneumoniae. Controlled antibiotic use in children might prevent children from carrying the antibiotic resistant S. pneumoniae.

Macrolide susceptibility and serotype specific macrolide resistance of invasive isolates of Streptococcus pneumoniae in Germany from 1992 to 2008

Background

Macrolide resistant Streptococcus pneumoniae has been on a gradual increase in Germany for over a decade. The current study was undertaken against the background of the recent observation of declining macrolide resistance rates especially among German children. Nationwide surveillance of invasive pneumococcal disease has been conducted in Germany since 1992. A population- and laboratory-based approach was used to collect data on invasive pneumococcal disease, and isolates sent to the National Reference Center for Streptococci by diagnostic microbiological laboratories from 1992 to 2008 were included in this study.

Results

From 1992 to 2008, data on macrolide susceptibility were available for 11,807 invasive isolates. 8,834 isolates (74.8%) were from adults (≥ 16 years), and 2,973 isolates (25.2%) from children (< 16 years). The overall nonsusceptibility rate of all isolates was 16.2% (intermediate, 0.2%; resistant, 16.0%). Higher resistance rates were observed among children (intermediate, 0.2%; resistant, 23.8%) than among adults (intermediate, 0.3%; resistant 13.4%). Maximum nonsusceptibility rates during the period under study were observed in 2005 (children: intermediate, 0.3%; resistant, 32.3%; adults: intermediate, 0.0%; resistant, 18.6%), while nonsusceptibility rates in 2008 were considerably lower, especially for children (children: intermediate, 0.0%; resistant, 15.2%; adults: intermediate, 0.1%; resistant, 12.9%). The rate of resistance was higher among the vaccine serotypes (7-valent, 36.6%; 10-valent, 28.2%; 13-valent, 24.3%) than among the non vaccine serotypes (non 7-valent, 6.5%; non 10-valent, 7.4%; non 13-valent, 6.3%). Serotype 14 (69.6% nonsusceptibility) proved to be the most resistant serotype.

Conclusions

There has been a considerable and statistically significant decrease in macrolide nonsusceptibility in Germany since 2005, especially among children.

Evolving trends in Streptococcus pneumoniae resistance: implications for therapy of community-acquired bacterial pneumonia

Pneumonia is a major infectious disease associated with significant morbidity, mortality and utilisation of healthcare resources. Streptococcus pneumoniae is the predominant pathogen in community-acquired pneumonia (CAP), accounting for 20-60% of bacterial cases. Emergence of multidrug-resistant S. pneumoniae has become a significant problem in the management of CAP. Although pneumococcal conjugate vaccine usage in children has led to significant decreases in morbidity and mortality due to S. pneumoniae in all age groups, disease management has been further complicated by the unexpected increase in resistant serotypes, such as 19A, in some regions. Until rapid and accurate diagnostic tests become available, initial treatment of CAP will remain empirical. Thus, selection of appropriate antimicrobial therapy for CAP must be based on prediction of the most likely pathogens and their local antimicrobial susceptibility patterns. This article reviews information on antimicrobial resistance patterns amongst S. pneumoniae and implications for managing CAP.

Risk factors for antibiotic-resistant Escherichia coli carriage in young children in Peru: community-based cross-sectional prevalence study

Few studies have examined the influence of individual-, household-, and community-scale risk factors on carriage of resistant commensal bacteria. We determined children's medical, agricultural, and environmental exposures by household, pharmacy, and health facility surveys and Escherichia coli cultures of children, mothers' hands, household animals, and market chickens in Peru. Among 522 children with a positive stool culture, by log-binomial regression, using "any antibiotic" and 1-14 (versus 0) sulfa doses in the past 3 months increased children's risk, respectively, for ampicillin- and sulfamethoxazole-resistant E. coli carriage (P = 0.01-0.02). Each household member taking "any antibiotic" increased children's risk for sulfamethoxazole- and multidrug-resistant E. coli carriage (P < 0.0001). Residence in a zone where a larger proportion of households served home-raised chicken (as contrasted with intensively antibiotic-raised market chicken) protected against carrying E. coli resistant to all drugs (P = 0.0004-0.04). Environmental contamination with drug-resistant bacteria appeared to significantly contribute to children's carriage of antibiotic-resistant E. coli.

Decreased Streptococcus pneumoniae susceptibility to oral antibiotics among children in rural Vietnam: a community study

BACKGROUND

Streptococcus pneumoniae is the most significant bacterial cause of community-acquired pneumonia among children under five years worldwide. Updated resistance information of S. pneumoniae among children is essential to adjust the recommendations for empirical treatment of community-acquired pneumonia, which will have immense implications for local and global health. This study investigated the prevalence of antibiotic resistance in isolated strains of S. pneumoniae and relationship with antibiotic use and demographic factors of children under five in rural Vietnam in 2007.

METHODS

In Bavi district, 847 children 6 to 60 months were selected from 847 households. The main child-caregivers in the households were interviewed weekly using structured questionnaires to collect information of daily illness symptoms and drug use for the selected child over a four-week period (from March through June 2007). In the 3rd week, the children were invited for a clinical examination and to collect nasopharyngeal samples for S. pneumoniae identification. Etest and disk diffusion were used to test antibiotic susceptibility.

RESULTS

Of 818 participating children, 258 (32%) had ongoing respiratory infections, 421 (52%) carried S. pneumoniae, and 477 (58%) had used antibiotics within the previous three weeks. Of the 421 isolates, 95% were resistant to at least one antibiotic (401/421). Resistance to co-trimoxazole, tetracycline, phenoxymethylpenicillin, erythromycin and ciprofloxacin was 78%, 75%, 75%, 70% and 28%, respectively. Low resistance was noted for amoxicillin (4%), benzylpenicillin (4%), and cefotaxime (2%). The intermediate resistance to amoxicillin was 32%. Multidrug-resistance was seen in 60%. The most common pattern was co-resistance to co-trimoxazole, tetracycline and erythromycin. The proportion of children carrying resistant bacteria was higher among the children who had used antibiotics in the previous three weeks.

CONCLUSIONS

Resistance to commonly used antibiotics and multidrug-resistance of S. pneumoniae in the area is remarkably high. High-dose amoxicillin is the only investigated oral antibiotic that can possibly be used for treatment of community-acquired pneumococcal infections. Strategies to promote appropriate prescribing and dispensing of effective antibiotics should be immediately implemented for the benefit of local and global health.

Factors associated with acute otitis media in children due to penicillin intermediately resistant Streptococcus pneumoniae

OBJECTIVES

This study was conducted to analyze the association between recent antimicrobial use and acute otitis media (AOM) due to Streptococcus pneumoniae intermediately resistant to penicillin (PISP). The influence of drug resistance on the clinical course of AOM was also assessed.

METHODS

A retrospective cohort study was conducted in infants at Japanese Red Cross Medical Center, Tokyo. Children included in the study were under 24 months of age and diagnosed with AOM due to infection with S. pneumoniae between April 2002 and March 2007. Crude risk ratios (cRR) of PISP infection in cases with recent antibiotic use and other factors were obtained. The Mantel-Haenszel estimate was applied for the adjustment of cRR.

RESULTS

Of 35 children, 13 had AOM due to penicillin-susceptible S. pneumoniae (PSSP) and 22 had AOM due to PISP. The adjusted risk ratio (aRR) of penicillin antibiotic use within 1 month was 1.99 (95% confidence interval (CI): 1.36-2.92), and the aRR of penicillin antibiotic use within 1 week was 1.93 (95% CI: 1.33-2.67). Recent use of penicillin antibiotics was an associated factor for AOM due to PISP. The clinical course was not clearly different between cases infected with PSSP and those with PISP.

CONCLUSION

Recent use of penicillin antibiotics might be a selective pressure for PISP.

Host and microbiologic factors associated with mortality in Taiwanese children with invasive pneumococcal diseases, 2001 to 2006

We concurrently evaluated host- and organism-related factors in determining the outcomes of 160 invasive pneumococcal diseases episodes in 158 Taiwanese children during 2001 and 2006. Most (138/160, 86.2%) episodes occurred at age less than 60 months, and an underlying condition was present in 35 (22.2%) cases. Common disease syndromes included complicated pneumonia (29.4%), uncomplicated pneumonia (29.4%), occult bacteremia (17.5%), and meningitis (14.4%). Mortality (13/160, 8.1%) was associated with age less than 24 months, underlying conditions, meningitis, cytopenia, intensive care, and penicillin MIC >or=2 microg/mL in univariate analysis. Pneumococcal serotypes, genotypes, origin of infections, and discordant therapy did not influence the outcome. Multivariate analysis determined the presence of underlying conditions (adjusted odds ratio [OR], 30.5; 95% confidence interval [CI], 4.8-193.1) and penicillin MIC >or=2 microg/mL (adjusted OR, 8.1; 95% CI, 1.4-47.3), which are the independent predictors for fatality. This finding highlighted the importance of immunization of disadvantaged children, targeting drug-resistant pneumococci.

Pneumonia and other respiratory infections

Pneumonia is a leading killer of children in developing countries and results in significant morbidity worldwide. This article reviews the management of pneumonia and its complications from the perspective of both developed and resource-poor settings. In addition, evidence-based management of other respiratory infections, including tuberculosis, is discussed. Finally, the management of common complications of pneumonia is reviewed.

Pneumococcal antimicrobial resistance: therapeutic strategy and management in community-acquired pneumonia

Streptococcus pneumoniae has been consistently shown to represent the most frequent causative agent of community-acquired pneumonia (CAP) and pneumococcal antibiotic resistance towards different families of antibiotics continues to be a much-debated issue. Microbial resistance causes a great deal of confusion in choosing an empirical treatment for pneumonia and this makes it necessary to know which factors actually determine the real impact of antimicrobial resistance on the outcome of pneumococcal infections. Several different aspects have to be taken into account when analyzing this matter, such as the study design, the condition of the patient at the time of diagnosis, the choice of the initial antimicrobial regimen (combination or monotherapy) and the pharmacokinetic/pharmacodynamic variables of the chosen antibiotic. It is generally accepted that in the treatment of beta-lactam-resistant pneumococcal infections, the use of standard antipneumococcal beta-lactam agents is unlikely to impact negatively on the outcome of CAP when appropriate agents are given in sufficient doses. As a general rule, for infections with penicillin-sensitive strains, penicillin or an aminopenicillin in a standard dosage will be effective; in the cases of strains with intermediate resistance, beta-lactam agents are still considered appropriate treatment although higher dosages are recommended; finally, infections with isolates of high-level penicillin resistance should be treated with alternative agents such as the third-generation cephalosporins or the new antipneumococcal fluoroquinolones. In areas of high prevalence of high-level macrolide resistance, empirical monotherapy with a macrolide is not optimal for the treatment of hospitalised patients with moderate or moderately-severe CAP. Fluoroquinolones are considered to be excellent antibiotics in the treatment of pneumococcal CAP in adults, but their general recommendation has been withheld due to fears of a widespread development of resistance. Most international guidelines recommend combination therapy (beta-lactam plus a macrolide) for the treatment of hospitalised patients with CAP.

Management of community-acquired pneumonia in children

Community-acquired pneumonia (CAP) is a significant cause of childhood morbidity and mortality worldwide. Viral etiology is most common in young children and decreases with age. Streptococcus pneumoniae is the single most common bacterial cause across all age groups. Atypical organisms present similarly across all age groups and may be more common than previously recognized.A bacterial pneumonia should be considered in children presenting with fever >38.5 degrees C, tachypnea, and chest recession. Oxygen therapy is life saving and should be given when oxygen saturation is <92%. For non-severe pneumonia, oral amoxicillin is the antibacterial of choice with low failure rates reported. Severely ill children are traditionally treated with parenteral antibacterials. Penicillin non-susceptible S. pneumoniae prevalence rates are increasing and have been linked to community antibacterial prescribing. Most pneumococci remain sensitive to high-dose penicillin-based antibacterials but macrolide resistance is also a problem in some communities. However, primary combination treatment with macrolides is indicated in areas where there is a high prevalence of atypical organisms. The most common complications in CAP are parapneumonic effusions and empyema. The use of ultrasonography combined with intercostal drainage augmented with the use of fibrinolytic therapy has significantly reduced the morbidity associated with these complications. There is increasing evidence that a preventative strategy with the 7-valent pneumococcal conjugate vaccine (PCV-7) results in a significant fall in CAP in early childhood.

Implications of Streptococcus pneumoniae penicillin resistance and serotype distribution in Kuwait for disease treatment and prevention

Streptococcus pneumoniae causes serious infections. Treatment is difficult because of the emergence of penicillin resistance in S. pneumoniae. Pneumococcal vaccines offer the promise of control and prevention of pneumococcal infections. Serotype prevalence and penicillin susceptibility data for a country will predict the usefulness of the vaccines in that country. In Kuwait, the 23-valent polysaccharide and the 7-valent conjugate vaccines are being used without knowledge of the prevalent serotypes in the country. To obtain the necessary background information, data on penicillin susceptibility and serogroups were obtained from 397 consecutive clinical isolates collected during 2004 and 2005. Two hundred fifty-three isolates (64%) were penicillin resistant, and resistance was significantly higher in patients < or =15 years old and among the upper respiratory tract and eye isolates. The most common serotypes were 23F, 19F, 6A, 6B, 14, and 19A. Among the penicillin-resistant strains, the most common serotypes were 23F, 19F, 6B, 14, and 9A. Among the invasive strains, the most common serotypes were 14, 23F, 19A, and 9V. The polysaccharide vaccine gave 82% coverage against invasive infections in all age groups >2 years. The coverage of the 7-valent conjugate vaccine against invasive serotypes in children < or =2 years old was 55%. This moderate coverage by the conjugate vaccine against invasive infections in children necessitates a revised strategy on the use of the present conjugate vaccine and shows the need for formulation of an improved vaccine for superior coverage for Kuwait and possibly other countries of the Arabian Gulf.

Chloramphenicol versus ampicillin plus gentamicin for community acquired very severe pneumonia among children aged 2-59 months in low resource settings: multicentre randomised controlled trial (SPEAR study)

OBJECTIVE

To evaluate whether five days' treatment with injectable ampicillin plus gentamicin compared with chloramphenicol reduces treatment failure in children aged 2-59 months with community acquired very severe pneumonia in low resource settings.

DESIGN

Open label randomised controlled trial.

SETTING

Inpatient wards within tertiary care hospitals in Bangladesh, Ecuador, India, Mexico, Pakistan, Yemen, and Zambia.

PARTICIPANTS

Children aged 2-59 months with WHO defined very severe pneumonia.

INTERVENTION

Chloramphenicol versus a combination of ampicillin plus gentamicin.

MAIN OUTCOME MEASURES

Primary outcome measure was treatment failure at five days. Secondary outcomes were treatment failure defined similarly among all participants evaluated at 48 hours and at 10 and 21 days.

RESULTS

More children failed treatment with chloramphenicol at day 5 (16% v 11%; relative risk 1.43, 95% confidence interval 1.03 to 1.97) and also by days 10 and 21. Overall, 112 bacterial isolates were obtained from blood and lung aspirates in 110 children (11.5%), with the most common organisms being Staphylococcus aureus (n=47) and Streptococcus pneumoniae (n=22). In subgroup analysis, bacteraemia with any organism increased the risk of treatment failure at 21 days in the chloramphenicol group (2.09, 1.41 to 3.10) but not in the ampicillin plus gentamicin group (1.12, 0.59 to 2.13). Similarly, isolation of S pneumoniae increased the risk of treatment failure at day 21 (4.06, 2.73 to 6.03) and death (5.80, 2.62 to 12.85) in the chloramphenicol group but not in the ampicillin plus gentamicin group. No difference was found in treatment failure for children with S aureus bacteraemia in the two groups, but the power to detect a difference in this subgroup analysis was low. Independent predictors of treatment failure by multivariate analysis were hypoxaemia (oxygen saturation <90%), receiving chloramphenicol, being female, and poor immunisation status.

CONCLUSION

Injectable ampicillin plus gentamicin is superior to injectable chloramphenicol for the treatment of community acquired very severe pneumonia in children aged 2-59 months in low resource settings.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN39543942.

Epidemiology, clinical characteristics and antimicrobial resistance patterns of community-acquired pneumonia in 1702 hospitalized children in Singapore

OBJECTIVE AND BACKGROUND

Childhood community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide. The features of childhood CAP vary between countries. The aim of this study was to delineate the clinical characteristics, complications, spectrum of pathogens and patterns of antimicrobial resistance associated with hospitalized cases of childhood CAP in Singapore.

METHODS

A retrospective study was conducted of patients discharged from Singapore's only children's hospital over a 3-year period with a principal diagnosis of CAP.

RESULTS

A total of 1702 children, with a median age of 4.2 years (range: 1 month-16.3 years) were enrolled. A pathogen was identifiable in 38.4% of cases, including Mycoplasma pneumoniae in 20.3%, typical respiratory bacteria in 10.3% (64.6%Streptococcus pneumoniae; 21.7% non-typeable Haemophilus influenzae), viruses in 5.5% and mixed bacterial/viral infections in 2%. The majority of M. pneumoniae infections were in school-aged children (>5 years). Severity of infection was greater in CAP caused by typical bacteria, as reflected by length of hospital stay, CRP level, white cell and absolute neutrophil counts. Mortality from typical bacterial infections (8.9%) exceeded that from M. pneumoniae (0.3%) and viral pneumonias (0%) (P < 0.001). Aminopenicillins were often prescribed empirically for suspected S. pneumoniae and H. influenzae infections; however, resistance to these agents was frequently documented among S. pneumoniae (58.5%) and H. influenzae isolates (51%).

CONCLUSION

In Singaporean children hospitalized with CAP, M. pneumoniae is the most commonly identified causative organism, followed by common respiratory viruses, S. pneumoniae and H. influenzae. Streptococcus pneumoniae and H. influenzae are associated with greater severity of infection than other organisms, and have high levels of resistance to commonly prescribed antibiotics.

Comparison of standard versus double dose of amoxicillin in the treatment of non-severe pneumonia in children aged 2-59 months: a multi-centre, double blind, randomised controlled trial in Pakistan

INTRODUCTION

WHO pneumonia case management guidelines recommend oral amoxicillin as first line treatment for non-severe pneumonia. Increasing treatment failure rates have been reported over a period of time, which could possibly be due to increasing minimum inhibitory concentrations of Streptococcus pneumoniae and Haemophilus influenzae for amoxicillin. Microbiological data show that this resistance can be overcome by increasing amoxicillin dosage. Based on this data, we examined whether we can improve the clinical outcome in non-severe pneumonia by doubling the dose of amoxicillin.

METHODS

A double blind randomised controlled trial was conducted in the outpatient departments of four large hospitals in Pakistan. Children aged 2-59 months with non-severe pneumonia were randomised to receive either standard (45 mg/kg/day) or double dose (90 mg/kg/day) oral amoxicillin for 3 days and then followed up for 14 days. Final outcome was treatment failure by day 5.

RESULTS

From September 2003 to June 2004, 876 children completed the study. 437 were randomised to standard and 439 to double dose oral amoxicillin. 20 (4.5%) children in the standard and 25 (5.7%) in the double dose group had therapy failure by day 5. Including the relapses, by day 14 there were 26 (5.9%) cumulative therapy failures with standard and 35 (7.9%) with double dose amoxicillin. These differences were not statistically significant (p = 0.55 and p = 0.29, respectively).

CONCLUSION

Clinical outcome in children aged 2-59 months with non-severe pneumonia is the same with standard and double dose oral amoxicillin. Non-severe pneumonia can be treated effectively and safely with a 3 day course of a standard dose.

Changing trends in antimicrobial-resistant pneumococci: it's not all bad news

In the early 1990s, we witnessed a dramatic and relentless increase in multidrug-resistant pneumococci worldwide. However, there is now evidence of decreasing resistance to some antimicrobials in some regions of the world. This may well be a result of several initiatives to promote the judicious use of antimicrobials, as well as the introduction of the pneumococcal conjugate vaccine, suggesting that the fight against resistance is maybe not futile.

Severe pneumococcal pneumonia: new strategies for management

PURPOSE OF REVIEW

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia worldwide and is the most likely causative pathogen in patients with community-acquired pneumonia admitted to the intensive care unit. Bacteremic pneumococcal pneumonia is an advanced stage of severe pneumococcal pneumonia. Improvement in the management of bacteremic pneumococcal pneumonia has the potential for improving the survival for severe pneumococcal pneumonia.

RECENT FINDINGS

Non-culture methods, especially the Binax urinary antigen test, can increase the diagnostic yield for pneumococcal pneumonia, allowing targeted antimicrobial therapy (specifically penicillin). In-vitro resistance to penicillin has increased over the past decade; however, it has not led to clinical failure when used for pneumococcal pneumonia.

SUMMARY

Hospitalized patients with community-acquired pneumonia should have blood cultures obtained to confirm the possibility of bacteremic pneumococcal pneumonia. Based on pharmacodynamic properties, parenteral penicillin remains the drug of choice to treat pneumococcal pneumonia regardless of in-vitro resistance. Combination antimicrobial therapy will likely improve survival of patients with bacteremic pneumococcal pneumonia among the subset of critically ill patients.

Otitis media today: a challenge for physicians and the community

Acute otitis media is one of the most common causes of medical consultation worldwide, and has a high economic impact. In this review, a clear definition between acute otitis media and otitis media with effusion is presented. The microbiology and characterization of the main bacterial isolates in acute otitis media and the susceptibility patterns are reviewed, and the latest concepts in antimicrobial treatment are discussed. The need for courses that improve the capability of primary care physicians to diagnose acute otitis media using pneumatic otoscopy, and for parental education is also discussed.

Penicillin resistance and serotyping of Streptococcus pneumoniae in Latin America

Streptococcus pneumoniae (Strep. pneumoniae) is the main cause of bacterial pneumonia in children less than 5 years of age, with high mortality rates in developing countries. In 1993, the Regional System for Vaccines Group (SIREVA) of the pan-American Health Organisation (PAHO) began a study involving six Latin American countries to identify serotypes and their representativity in the new conjugated vaccines, and to determine the degree of resistance to penicillin. Serotypes 14 (highest resistance level), 5, 1, 6A/B, 23F, 7F, 9V, 19F, 18C, 19A, 9N, were prevalent in the region, with some differences among countries. Although resistance to penicillin ranged from 2% (Brazil) to 21.1% (Mexico), studies have shown that pneumonia caused by Strep. pneumoniae with diminished sensitivity to penillin can be treated with this antibiotic. Only 58% of the serotypes isolated in the region studied were represented in the seven-valent vaccine. Continual surveillance is essential to determine which formulation of conjugated vaccine will be suitable for use in Latin America.

Immunogenicity and protective efficacy of DnaJ (hsp40) of Streptococcus pneumoniae against lethal infection in mice

The present study was carried out to evaluate the immunogenicity and protective efficacy of DnaJ (hsp40) of Streptococcus pneumoniae, by cloning the full-length DnaJ of S. pneumoniae and expressing in heterologous host E. coli BL-21 (DE3). PCR amplified DnaJ was ligated in pQE-30 expression vector and subsequently transformed in E. coli DH5alpha strain. Cloning of DnaJ was confirmed by double digestion and PCR, followed by DNA sequencing. The His-tag containing recombinant protein was purified by Ni-NTA affinity chromatography. To determine the immunogenicity of DnaJ, the mice (10 mice/group) were immunized by injecting 40 microg DnaJ protein/mouse i.p. There was a significant increase in IgG titres (2 x 10(5)) in mice immunized with DnaJ protein. Isotyping studies revealed that antibodies produced are predominantly IgG2a type indicating the predominance of Th1 response. A significant increase in lymphocyte proliferation was observed in mice immunized with DnaJ protein as compared to the control mice. Further, there was a significant increase in IL-2 and gamma-IFN levels in culture supernatants of splenocytes isolated from immunized mice. To determine the efficacy of DnaJ vaccination in eliciting protection, the mice were challenged with 1 x 10(5)cells of S. pneumoniae A66 type 3 capsular strain intra-nasally after 7 days of last immunization. All the control mice died within 2 days of post-infection, while 70% of animals immunized with DnaJ survived the lethal challenge by S. pneumoniae. The study reveals that immunization of mice with DnaJ elicits protective immunity against S. pneumoniae infection.

Drug-resistant pneumococcal pneumonia: clinical relevance and approach to management

Community-acquired pneumonia is the most common infectious disease that causes death, with Streptococcus pneumoniae remaining the leading causative pathogen. The worldwide incidence of infections caused by pneumococci resistant to penicillin, macrolides, and other antimicrobial agents has increased at an alarming rate during the past 2 decades. Yet, these agents are still used as first-line empirical therapy in the outpatient setting. There are several reasons for this, including the infrequency of making a pathogen-specific diagnosis, the failure of studies to demonstrate the relevance of resistance, and the infrequency with which clinicians recognize clinical failures. Despite this, there is mounting evidence that supports the practice of using high doses of some antimicrobial agents, a more active antimicrobial agent within a class, or switching to another class of antimicrobial agents when a patient is identified as being at an increased risk of infection with a resistant pneumococcus. There is now information that will allow the physician to identify not only the patient at risk for infection with a resistant pneumococcus but also the antimicrobial class and, in some cases, the agent within the class to which the organism is more likely to be resistant. This will allow clinicians to better define optimal therapy for patients with community-acquired pneumonia.

Therapeutic options for pneumococcal pneumonia in Turkey

BACKGROUND

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality worldwide. Streptococcus pneumoniae continues to be the most important causative agent in CAP.

OBJECTIVE

This article reviews options for the empiric treatment of pneumococcal pneumonia in Turkey based on local epidemiologic data.

METHODS

This was a retrospective review of studies evaluating antimicrobial susceptibility patterns among clinical isolates of S pneumoniae in Turkey from 2000 onward. Relevant studies were identified through literature searches of both Turkish (Ulakbim and Pleksus) and international (MEDLINE) databases using the search terms S pneumoniae and Turkey. Only antibiotics likely to be used in pneumococcal pneumonia were evaluated. The minimum concentration required to inhibit 90% of isolates (MIC(90)) for each antibiotic was obtained by averaging all reported values to arrive at a single value for the entire country.

RESULTS

The MIC(90) for penicillin was 1 g/mL; among all isolates of S pneumoniae, 6.4% were penicillin resistant and 30.9% showed intermediate susceptibility. The MIC(90)s and overall rates of resistance (combined intermediate susceptibility and resistance) for the other antibiotics studied were as follows: cefaclor, 4 microg/mL (26.3%); cefuroxime, 2 microg/mL (15.4%); ceftriaxone, 0.25 microg/mL (0.75%); imipenem, 0.06 microg/mL (0%); erythromycin, 2 microg/mL (13.9%); clarithromycin, 2 microg/mL (13.7%); azithromycin, 2 microg/mL (13.8%); telithromycin, 0.06 microg/mL (no published breakpoints); trimethoprim-sulfamethoxazole, 4 microg/mL (63.8%); tetracycline, 16 microg/mL (24.6%); ciprofloxacin, 2 microg/mL (no published breakpoints); ofloxacin, 2 microg/mL (4%); levofloxacin, 1 microg/mL (0%); gemifloxacin, 0.06 microg/mL (no published breakpoints); and moxifloxacin, 0.06 microg/mL (0%). Penicillin G, at standard parenteral doses, has been shown to achieve concentrations above the MIC for >40% to 100% of the dosing interval, depending on the MIC of the isolate. Based on pharmacodynamic studies, the MIC(90) for penicillin in Turkey should easily be exceeded with the use of penicillin G 3 mU QID. In vitro, susceptibility is generally greater to amoxicillin than to penicillin, with average amoxicillin MIC values approximately 1 dilution lower than those for penicillin. Amoxicillin's better pharmacodynamic/pharmacokinetic properties relative to penicillin make it a reasonable option for the treatment of CAP. In pharmacodynamic studies, amoxicillin 1 g TID achieved and maintained serum concentrations of 2 to 4 microg/mL for at least 40% of the dosing interval. A new formulation of amoxicillin/clavulanate given 2000/125 mg BID is expected to eradicate isolates of S pneumoniae at an amoxicillin MIC < or = 4 microg/mL.

CONCLUSIONS

Based on data from Turkish surveillance studies performed from 2000 onward, high-dose parenteral penicillin G and parenteral/oral amoxicillin may be initial choices for the empiric treatment of uncomplicated pneumococcal pneumonia in Turkey. If these agents cannot be used for any reason, other options include parenteral cefuroxime, ceftriaxone, cefotaxime, newer quinolones, macrolides, and telithromycin. Due to elevated rates of resistance in Turkey, trimethoprim-sulfamethoxazole and tetracyclines are not recommended for empiric use in these infections.

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.

[Distribution of serotypes and antibiotic susceptibility patterns of Streptococcus pneumoniae strains isolated from children in Misiones, Argentina]

BACKGROUND

The aim of this study was to assess the local resistance patterns and serotypes of Streptococcus pneumoniae implicated in invasive infections in children in Hospital Provincial de Pediatría in Misiones, Argentina.

METHODS

A total of 101 strains isolated from sterile sites between June 1998 and June 2001 were studied. Strains were identified according to standard methods. Resistance patterns were determined by disk diffusion and a macrodilution method according to NCCLS guidelines. Capsular typing was based on the Quellung technique.

RESULTS

Among the total, 62% of pneumonia cases, 70% of pneumonia with pleural effusion and meningitis, and 78% of sepsis occurred in children younger than 2 years old (74% of the total). Twelve serotypes were detected among 71 strains analyzed. Types 14 (37.1%), 5 (21.4%), 1 (10%), 6A/6B (7.1%), 9N and 19A (5.7%) and 9V (4.3%), were the most frequent. Penicillin (PEN) resistance was detected in 39% of isolates: 17.5% had intermediate levels and 21.5% high levels of resistance. None of the strains had PEN MICs of > 4 microg/ml. PEN resistance was limited to 5 serotypes, with 84% corresponding to type 14. Among the 71 strains, in 50 CTX MICs were < or = 0.5 microg/ml, in 18 the MIC was 1 mg/ml and in 3 the MIC was 2 microg/ml. None of the strains had CTX MICs of > 2 microg/ml. Twenty-two percent of strains were resistant to tetracycline, 48% to trimethoprim-sulfamethoxazole (TMS), 11% to chloramphenicol (CLO) and 6.8% to erythromycin. None of the isolates were resistant to vancomycin, ofloxacin or rifampin. The most common combined resistance patterns were PEN-TMS (20%), PEN-CTX-TMS (7%, 3 strains with a CTX MIC of 2 .g/ml) and PEN-TMS-CLO (5%).

CONCLUSIONS

The local drug resistance patterns and serotype distribution defined in this study allow appropriate empirical therapy to be established in our area and provide information that can be used assess vaccination strategies as a preventive tool for the control of invasive pneumococcal infections.

Non-antibiotic treatment recommendations: delivery formats and implications for parent resistance

This study draws on a database of 570 community-based acute pediatric encounters in the USA and uses conversation analysis as a methodology to identify two formats physicians use to recommend non-antibiotic treatment in acute pediatric care (using a subset of 309 cases): recommendations for particular treatment (e.g., "I'm gonna give her some cough medicine.") and recommendations against particular treatment (e.g., "She doesn't need any antibiotics."). The findings are that the presentation of a specific affirmative recommendation for treatment is less likely to engender parent resistance to a non-antibiotic treatment recommendation than a recommendation against particular treatment even if the physician later offers a recommendation for particular treatment. It is suggested that physicians who provide a specific positive treatment recommendation followed by a negative recommendation are most likely to attain parent alignment and acceptance when recommending a non-antibiotic treatment for a viral upper respiratory illness.

Parent resistance to physicians' treatment recommendations: one resource for initiating a negotiation of the treatment decision

This article examines pediatrician-parent interaction in the context of acute pediatric encounters for children with upper respiratory infections. Parents and physicians orient to treatment recommendations as normatively requiring parent acceptance for physicians to close the activity. Through acceptance, withholding of acceptance, or active resistance, parents have resources with which to negotiate for a treatment outcome that is in line with their own wants. This article offers evidence that even in acute care, shared decision making not only occurs but, through normative constraints, is mandated for parents and physicians to reach accord in the treatment decision.

Effect of Ampicillin on the kinetics of colonization of Streptococcus pneumoniae and Lactobacillus fermentum in the respiratory tract of mice

Ampicillin was selected to further study the effect of this antibiotic on the colonization capability of S. pneumoniae and L. fermentum intranasally inoculated in a mice experimental model. The sensitivity of S. pneumoniae and L. fermentum to antibiotics was evaluated by different "in vitro" techniques. The results showed that both microorganisms have a typical pattern of sensitivity to antibiotics in these assays. The "in vivo" experiments showed that the treatment with Ampicillin increased the number of lactobacilli and neumococci in the groups of mice treated only with one of the microorganisms. In those mice treated with Lactobacillus, challenged later with neumococci and treated with Ampicillin, the pathogen in lung decreased on the 4th day, disappearing completely after on. The histological studies showed that the antibiotic treatment decreased the inflammatory response produced by the pathogen at the lung and trachea levels.

Antimicrobial susceptibility patterns of Streptococcus pneumoniae in Mexico

The susceptibility to 14 beta-lactam and non-beta-lactam antimicrobial agents was evaluated for Streptococcus pneumoniae from patients with community-acquired respiratory infections in a Mexican medical center. Three hundred fifteen pneumococcal isolates obtained from patients between 1995 and 2001 were tested by the broth microdilution test. Fifty-two percent of the isolates were nonsusceptible to penicillin (minimal inhibitory concentration, >0.06 microg/mL). Penicillin-nonsusceptible isolates were more likely to exhibit resistance to cephalosporins, macrolides, ciprofloxacin, trimethoprim/sulfamethoxazole, chloramphenicol, and tetracycline when compared to penicillin-susceptible isolates. Ninety-three percent of the penicillin-nonsusceptible isolates were resistant to at least one other class of antimicrobials, in contrast to only 47% of the penicillin-susceptible strains (p < 0.0001). More than 90% of the tested isolates were susceptible to amoxicillin/clavulanate, ceftriaxone, levofloxacin, and gatifloxacin. Reduced susceptibility to penicillin was considered to be a reliable marker for the higher probability of multidrug resistance, thus requiring in vitro tests to guide chemotherapy or the choices of parenteral extended spectrum cephalosporins or newer respiratory quinolones.

Quinolone Resistance among Pneumococci: Therapeutic and Diagnostic Implications

Fluoroquinolones are widely recommended as empirical monotherapy for community-acquired pneumonia. Since 1999, case reports of failure of levofloxacin therapy due to levofloxacin-resistant strains of Streptococcus pneumoniae have started to appear. Most worrying is that, in some cases, levofloxacin resistance has been acquired by pneumococci within days of the initiation of therapy. Because use of current clinical antimicrobial resistance breakpoints fail to identify the majority of S. pneumoniae isolates with only first-step mutations, current treatment guidelines not only may have implications with regard to the ability of surveillance programs to detect emerging resistance but may have therapeutic implications as well.

Drug‐Resistant Pneumococcal Pneumonia: Clinical Relevance and Related Factors

A multicenter study of 638 cases of community-acquired pneumonia due to Streptococcus pneumoniae (SP-CAP) was performed to assess current levels of resistance. Of the pneumococcal strains, 35.7% had an minimum inhibitory concentration (MIC) of penicillin of > or =0.12 microg/mL (3 isolates had an MIC of 4 microg/mL), 23.8% had an MIC of erythromycin of 128 microg/mL, and 22.2% were multidrug resistant. Logistic regression determined that chronic pulmonary disease (odds ratio [OR], 1.44], human immunodeficiency virus infection (OR, 1.98), clinically suspected aspiration (OR, 2.12), and previous hospital admission (OR, 1.69) were related to decreased susceptibility to penicillin, and previous admission (OR, 1.89) and an MIC of penicillin of MIC > or =0.12 microg/mL (OR, 15.85) were related to erythromycin resistance (MIC, > or =1 microg/mL). The overall mortality rate was 14.4%. Disseminated intravascular coagulation, empyema, and bacteremia were significantly more frequent among patients with penicillin-susceptible SP-CAP. Among isolates with MICs of penicillin of > or =0.12 microg/mL, serotype 19 was predominant and was associated with a higher mortality rate. In summary, the rate of resistance to beta -lactams and macrolides among S. pneumoniae that cause CAP remains high, but such resistance does not result in increased morbidity.

High-Dose Versus Standard-Dose Amoxicillin for Acute Otitis Media

BACKGROUND:

Emergence of drug-resistant bacteria has led to a recommendation to use high-dose (HD) amoxicillin (80–90 mg/kg/d) rather than standard-dose (SD) amoxicillin (40–45 mg/kg/d) to treat children with acute otitis media (AOM).

OBJECTIVE:

To compare the efficacy and tolerability of HD versus SD amoxicillin among children with AOM who were considered at low risk for infection with antibiotic-resistant bacteria.

METHODS:

A double-blind, randomized, 3-year clinical trial was conducted using participants who met the following criteria: age >3 mo, weight ≤18 kg, diagnosed with AOM, and candidates for treatment with amoxicillin. The primary endpoint was treatment success at a 3- to 4-day follow-up visit based on the clinical decision to continue the prescribed antibiotic therapy for AOM. Other endpoints included duration of illness, number of office visits and telephone calls related to illness, total number of subsequent AOM episodes, and number of adverse effects.

RESULTS:

The absolute difference in antibiotic failure rate with SD versus HD amoxicillin at the follow-up visit was nonsignificant (95% CI–1.5% to 3.4%; p = 0.78). The mean duration of illness was similar for both doses of amoxicillin (3 ± 2 d). The number of office visits and telephone calls related to illness and the number of subsequent AOM episodes did not differ between the 2 treatment groups. HD amoxicillin did not result in a greater incidence of adverse effects than SD amoxicillin.

CONCLUSIONS:

HD amoxicillin had neither benefit nor detriment compared with SD for AOM in children at low risk for infection with antibiotic-resistant bacteria.

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.

Invasive pneumococcal disease in Costa Rican children: a seven year survey

BACKGROUND

Streptococcus pneumoniae is a leading cause of invasive bacterial disease in children worldwide. Although morbidity and mortality associated with invasive pneumococcal disease (IPD) are known to be high in Latin American infants, the current situation for Central American children is unclear.

METHODS

A 7-year retrospective review of IPD cases (January 1995 to December 2001) treated at the National Children's Hospital in San José, Costa Rica.

RESULTS

We analyzed 135 episodes that occurred in 132 patients. The mean age of presentation was 35.7 months (range, 0 to 11.4 ys), with 73.3% of all episodes occurring in patients <5 years of age and 56% occurring in patients <24 months of age. Underlying medical conditions were present in 47% of children. The most common clinical presentations were meningitis in 56 (41.5%) patients, pneumonia in 36 (26.7%), bacteremia alone in 30 (22.2%), peritonitis in 10 (7.4%), septic arthritis in 2 (1.5%) and osteomyelitis in 1 (0.7%). The case fatality rate was 14.4%, and children <2 years of age had the highest rates of complications, sequelae and death. Penicillin or cefotaxime nonsusceptibility was observed in 14.3% (10.7% intermediate, 3.6% resistant) and 4.5% (1.5% intermediate, 3% resistant) of tested isolates, respectively.

CONCLUSIONS

IPD in Costa Rica is associated with high morbidity and mortality, particularly among young infants. Most prevalent IPD are the ones observed in developed countries before the introduction of current conjugated vaccine. Penicillin and third generation cephalosporin resistance in invasive cases is present at low rates.

The epidemiology of antibiotic resistance in Streptococcus pneumoniae and the clinical relevance of resistance to cephalosporins, macrolides and quinolones

Invasive non-meningeal pneumococcal infections remain a major cause of morbidity and mortality worldwide. The factors affecting the epidemiology and mortality of pneumococcal infections are discussed. The increase and spread of resistance to antimicrobial agents among pneumococci is a cause of concern to the clinician. There are links between the usage of antibacterial agents and the development of resistance. Resistance to penicillin and other beta-lactams has become widespread but this does not appear to have decreased the efficacy of some of these agents against non-meningeal infections. There is evidence that the good pharmacokinetic and pharmacodynamic features of the third generation cephalosporins (cefotaxime and ceftriaxone) contribute to their efficacy in vivo. New breakpoints for cefotaxime and ceftriaxone against non-meningeal pneumococcal isolates were proposed by the National Committee for Clinical Laboratory Standard (NCCLS, US), based on the clinical evidence of the efficacy of these drugs. In contrast there is increasing evidence that resistance to macrolides can lead to a poor clinical response. Fluoroquinolones have been widely used to treat respiratory tract infections among others, and pneumococcal resistance to these agents in vitro, although currently low, is increasing. There are reports that resistance to fluoroquinolones can develop during treatment and may be reflected in a lack of clinical response. Several clinical and epidemiological variables (e.g. prior antibiotic use) can be useful to identify patients at risk from infections with antibiotic-resistant pneumococci. These patients would be those who would benefit the most from a pneumococcal vaccination programme.