Management of community-acquired pediatric pneumonia in an era of increasing antibiotic resistance and conjugate vaccines

First global report about the prevalence of multi-drug resistant Haemophilus influenzae: a systematic review and meta-analysis

BACKGROUND

In recent decades, the prevalence of antibiotic resistance is increasing in Haemophilus influenzae (Haemophilus influenzae), which poses important challenges to global health. This research offers a comprehensive meta-analysis of the global epidemiology of multi-drug resistant (MDR) H. influenzae.

METHODS

In this study, we conducted a meta-analysis based on PRISMA checklist. Electronic databases including PubMed, ISI Web of Science, Scopus, EMBASE, and Google Scholar were reviewed using keywords related to H. influenzae and antibiotic resistance. Eligible studies were selected based on stringent inclusion and exclusion criteria. Then, data from these studies were analyzed using the Comprehensive Meta-Analysis (CMA) software.

RESULTS

Of 375 retrieved articles, 16 met the inclusion criteria. These studies were conducted from 2003 to 2023 and analyzed data from 19,787 clinical isolates of H. influenzae. The results showed different levels of resistance of H. influenzae to different antibiotics: ampicillin (36%), azithromycin (15.3%), ceftriaxone (1.4%), etc. The global prevalence for beta-lactamases producing H. influenzae and MDR H. influenzae was measured 34.9% and 23.1%, respectively. The prevalence rate of MDR H. influenzae was higher in Asian countries (24.6%) compared to Western regions (15.7%). MDR H. influenzae had the highest prevalence in meningitis cases (46.9%) and the lowest prevalence in acute otitis media (0.5%).

CONCLUSIONS

The prevalence of MDR H. influenzae has been increasing worldwide, especially in Asian regions. This highlights the urgent need for monitoring and implementation of effective antibiotic stewardship programs globally.

Etiological and clinical characteristics of severe pneumonia in pediatric intensive care unit (PICU)

OBJECTIVE

To analyze the etiological distribution characteristics of pediatric patients with severe pneumonia admitted to the Pediatric Intensive Care Unit (PICU), in order to provide a reference for the rational use of clinical antimicrobial drugs.

METHODS

A retrospective analysis of pediatric patients admitted to PICU with a diagnosis of severe pneumonia from January 2018 to December 2021 was performed and statistical analysis of pathogenic characteristics was performed.

RESULTS

A total of 649 pathogens were detected in 515 children, with a positive detection rate of 77.48%. Bacteria were detected at the highest rate (40.52%), followed by viruses (34.35%), atypical pathogens (19.72%) and fungal (4.31%). Gram-positive infections were dominated by Staphylococcus aureus (39.56%) and Streptococcus pneumoniae (32.97%), and Gram-negative infections were dominated by Acinetobacter Bahmani (16.28%) and Haemophilus influenzae (15.12%), followed by Klebsiella pneumoniae (13.95%) and Pseudomonas aeruginosa (12.21%). Viral infections were dominated by respiratory syncytial virus (25.65%) and EB virus (20.43%), fungal infections were dominated by Candida albicans (50.0%). The proportion of children infected with single pathogen (49.62%) was comparable to that of those with mixed infections (50.38%). There were statistically significant differences in the distribution of children with single pathogen infection by gender (P < 0.05). The age distribution of children with single bacterial, single viral and single fungal infections was statistically different (P < 0.05). There was no significant difference in the distribution of onset season in children with single pathogen infections (P > 0.05), but the number of children with single viral infections was significantly higher in winter and spring than that in summer and autumn, and the difference was statistically significant (P < 0.05). A mixture of 2 pathogens (77.61%) accounted for the majority of mixed infections, there were statistical differences in the distribution of bacterial + viral infection in terms of gender, age, and onset season (P < 0.05), children with viral + mycoplasma infection in terms of gender and age (P < 0.05), and children with viral + fungal infection in terms of gender (P < 0.05), and children with bacterial + mycoplasma infection in terms of age and onset season (P < 0.05). Among the children infected with 3 pathogens, there were statistically significant differences in the distribution of bacterial + viral + fungal and viral + mycoplasma + fungal infections in terms of gender (P < 0.05), and children with bacterial + viral + mycoplasma infection in terms of age (P < 0.05), while there was no significant difference in the distribution of onset season (P > 0.05). There were no significant differences in the distribution of children infected with 4 pathogens in terms of gender, age and onset season (P > 0.05).

CONCLUSION

The pathogens of pediatric patients with severe pneumonia in PICU commonly involves bacteria and viruses. As the age of children grows, the detection rate of bacteria shows a decreasing trend, and the pathogenic spectrum gradually changes from bacteria to mycoplasma and viruses, and the number of mixed infections gradually increase. Rational selection of antimicrobial drugs needs to consider pathogenic characteristics of different age, gender, and onset season in clinical practice.

Predicting the causative pathogen among children with pneumonia using a causal Bayesian network

BACKGROUND

Pneumonia remains a leading cause of hospitalization and death among young children worldwide, and the diagnostic challenge of differentiating bacterial from non-bacterial pneumonia is the main driver of antibiotic use for treating pneumonia in children. Causal Bayesian networks (BNs) serve as powerful tools for this problem as they provide clear maps of probabilistic relationships between variables and produce results in an explainable way by incorporating both domain expert knowledge and numerical data.

METHODS

We used domain expert knowledge and data in combination and iteratively, to construct, parameterise and validate a causal BN to predict causative pathogens for childhood pneumonia. Expert knowledge elicitation occurred through a series of group workshops, surveys and one-on-one meetings involving 6-8 experts from diverse domain areas. The model performance was evaluated based on both quantitative metrics and qualitative expert validation. Sensitivity analyses were conducted to investigate how the target output is influenced by varying key assumptions of a particularly high degree of uncertainty around data or domain expert knowledge.

RESULTS

Designed to apply to a cohort of children with X-ray confirmed pneumonia who presented to a tertiary paediatric hospital in Australia, the resulting BN offers explainable and quantitative predictions on a range of variables of interest, including the diagnosis of bacterial pneumonia, detection of respiratory pathogens in the nasopharynx, and the clinical phenotype of a pneumonia episode. Satisfactory numeric performance has been achieved including an area under the receiver operating characteristic curve of 0.8 in predicting clinically-confirmed bacterial pneumonia with sensitivity 88% and specificity 66% given certain input scenarios (i.e., information that is available and entered into the model) and trade-off preferences (i.e., relative weightings of the consequences of false positive versus false negative predictions). We specifically highlight that a desirable model output threshold for practical use is very dependent upon different input scenarios and trade-off preferences. Three commonly encountered scenarios were presented to demonstrate the potential usefulness of the BN outputs in various clinical pictures.

CONCLUSIONS

To our knowledge, this is the first causal model developed to help determine the causative pathogen for paediatric pneumonia. We have shown how the method works and how it would help decision making on the use of antibiotics, providing insight into how computational model predictions may be translated to actionable decisions in practice. We discussed key next steps including external validation, adaptation and implementation. Our model framework and the methodological approach can be adapted beyond our context to broad respiratory infections and geographical and healthcare settings.

Prevalence of and outcomes from Staphylococcus aureus pneumonia among hospitalized patients in the United States, 2009-2012

BACKGROUND

The burden of Staphylococcus aureus pneumonia is unknown despite being a major cause of mortality. We investigated national estimates of methicillin-resistant S aureus (MRSA) and methicillin-susceptible S aureus (MSSA) pneumonias and predictors of in-hospital mortality and hospital length of stay (LOS).

METHODS

This was a retrospective analysis of the National Inpatient Sample from 2009-2012. Adult patients with an ICD-9-CM primary diagnosis code for MRSA or MSSA pneumonia were included. Data weights were used to derive national estimates. Prevalence rates were reported per 100,000 hospital discharges, with trends presented descriptively.

RESULTS

There were 104,562 patients who had a primary diagnosis of S aureus pneumonia, with 81,275 from MRSA. MRSA pneumonia prevalence decreased steadily from 2009 (75.6 cases per 100,000 discharges) to 2012 (56.6 cases per 100,000 discharges), with MSSA pneumonia experiencing a slight decrease. Mortality rates decreased between 2009 and 2012 for MRSA pneumonia (7.9% to 6.4%) and MSSA pneumonia (6.9% to 4.7%; P = .008). LOS was higher for MRSA (6.9-7.8 days) compared with MSSA (6.1-6.4 days).

CONCLUSIONS

The prevalence of MRSA pneumonia has decreased among hospitalized adults in the United States in recent years accompanied by improvements in mortality and LOS. Although the prevalence of MRSA pneumonia is declining, national vigilance is still warranted.

One Center's Guide to Outpatient Management of Pediatric Cystic Fibrosis Acute Pulmonary Exacerbation

Cystic fibrosis (CF) is a chronic disorder characterized by acute pulmonary exacerbations that comprise increased cough, chest congestion, increased mucus production, shortness of breath, weight loss, and fatigue. Typically, severe episodes are treated in the inpatient setting and include intravenous antimicrobials, airway clearance therapy, and nutritional support. Children with less-severe findings can often be managed as outpatients with oral antimicrobials and increased airway clearance therapy at home without visiting the specialty CF center to begin treatment. Selection of specific antimicrobial agents is dependent on pathogens found in surveillance culture, activity of an agent in patients with CF, and the unique physiology of these patients. In this pediatric review, we present our practice for defining acute pulmonary exacerbation, deciding treatment location, initiating treatment either in-person or remotely, determining the frequency of airway clearance, selecting antimicrobial therapy, recommending timing for follow-up visit, and recognizing and managing treatment failures.

Treatment of Childhood Complicated Community-Acquired Pneumonia with Amoxicillin/Sulbactam

The clinical and microbiological efficacy, as well as the tolerability of the amoxicillin/sulbactam combination as empiric treatment for complicated community-acquired pneumonia (CCAP) were evaluated in children from 3 months to 15 years with CCAP who were randomized 1:1 to receive either amoxicillin/sulbactam or cefuroxime. Of 234 patients hospitalized with CCAP in the study period (June, 1999-April, 2002), 62 patients qualified for the study: 32 received amoxicillin/sulbactam and 30 cefuroxime. Two were excluded. Demographic and clinical data showed that both groups were comparable at entry. One etiologic agent was identified in 55% of the patients, with Streptococcus pneumoniae being the most frequent. After treatment, the days of fever, duration of intravenous treatment, and hospitalization stay were similar in both groups. Overall favorable clinical responses were comparable: 97% for amoxicillin/sulbactam vs 100% for the comparative therapy. There was good tolerance to both drugs. Amoxicillin/sulbactam produced a satisfactory therapeutic outcome similar to that of cefuroxime for treatment of CCAP, and may be an appropriate choice for the treatment of this serious pediatric infection.

Risk factors for methicillin-resistant Staphylococcus aureus in patients with community-onset and hospital-onset pneumonia

OBJECTIVES

The risk factors for methicillin-resistant Staphylococcus aureus (MRSA) pneumonia have not been fully characterized and are likely to be different depending on whether infection is acquired in the community or the hospital.

METHODS

We conducted a case-control study of 619 adults hospitalized between 2005 and 2010 with either MRSA or methicillin-sensitive S. aureus (MSSA) pneumonia. Patients with a respiratory culture within 48 h of hospitalization had community-onset pneumonia whereas patients with a culture collected after this time point had hospital-onset pneumonia.

RESULTS

Among patients with community-onset disease, the risk for MRSA was increased by tobacco use (OR 2.31, CI 1.23-4.31), chronic obstructive pulmonary disease (OR 3.76, CI 1.74-8.08), and recent antibiotic exposure (OR 4.87, CI 2.35-10.1) in multivariate analysis while patients with hospital-onset disease had an increased MRSA risk with tobacco use (OR 2.66, CI 1.38-5.14), illicit drug use (OR 3.52, CI 2.21-5.59), and recent antibiotic exposure (OR 2.04, CI 3.54-13.01). Hospitalization within the prior three months was associated with decreased risk (OR 0.64, CI 0.46-0.89) in multivariate analysis.

CONCLUSIONS

This study suggests there are common and distinct risk factors for MRSA pneumonia based on location of onset. The decreased risk for MRSA pneumonia associated with recent hospitalization is unexpected and warrants further investigation.

SUMMARY

This case-control study showed that there are common and distinct risk factors associated with MRSA pneumonia depending on whether the infection onset is in the hospital or in the community. Recent hospitalization was unexpectedly shown to be associated with decreased risk for MRSA pneumonia and warrants further investigation.

Comparative effectiveness of empiric β-lactam monotherapy and β-lactam-macrolide combination therapy in children hospitalized with community-acquired pneumonia

OBJECTIVE

To determine the comparative effectiveness of β-lactam monotherapy and β-lactam and macrolide combination therapy on clinical outcomes in the treatment of children hospitalized with community-acquired pneumonia (CAP).

STUDY DESIGN

This multicenter retrospective cohort study included children aged 1-18 years who were hospitalized with CAP and received β-lactam antibiotic therapy either alone or in combination with a macrolide. Data were obtained from the Pediatric Health Information System. Associations between empiric antibiotic therapy and hospital readmission for the same episode of pneumonia were estimated using exact logistic regression. Associations between empiric antibiotic therapy and length of hospital stay were estimated using a generalized estimating equation with negative binomial distribution.

RESULTS

There were 20 743 patients hospitalized with CAP. Of these, 24% received β-lactam and macrolide combination therapy on admission. Compared with children who received β-lactam monotherapy, children who received β-lactam plus macrolide combination therapy were 20% less likely to stay in the hospital an additional day (adjusted relative risk 0.80; 95% CI, 0.75-0.86) but did not have a different readmission rate (relative risk 0.69; 95% CI, 0.41-1.12). An effect of combination treatment on reduced length of stay was not evident in children <6 years of age but increased with increasing age groups thereafter.

CONCLUSION

School-aged patients hospitalized with CAP who received β-lactam plus macrolide combination therapy have a shorter length of stay and similar rates of readmission compared with school-aged patients who receive β-lactam monotherapy.

Antimicrobial-resistant Streptococcus pneumoniae: trends and management

Management of pneumococcal infections has been challenged by the development of resistance and, more recently, the unexpected spread of resistant clones of serotypes, such as 19A, following the introduction of a conjugate pneumococcal vaccine for use in children in 2000. High-dose penicillin G and many other agents continue to be efficacious parenterally for pneumonia and bacteremia. However, treatment options for meningitis and for infections treated with oral agents, particularly in children, have been limited by resistance. Empiric treatment guidelines should reflect the emerging threats from increased drug resistance. Compliance with guidelines by physicians and patients is important to prevent further development of resistance as new classes of agents are unlikely to be available in the next decade.

Community-acquired pneumonia: a review and recent advances

In the beginning of this 21st century, community-acquired pneumonias (CAP) are still responsible for a significant number of deaths among young children in many developing countries. Public health initiatives such as those proposed by the World Health Organization (WHO) for the management of CAP by means of identifying highly predictable signs and symptoms have had great positive impact in some communities. Still, this approach induces an overdiagnosis and overtreatment of CAP in children below the age of 5 years due to the misclassification of pneumonia in children with fast breathing associated with viral bronchiolitis. Even among children of developed countries, CAP is an important public health problem and many aspects of current diagnostic and management measures are discussed here. In this article, we review the epidemiology and basic concepts of CAP and update current information on clinical evaluation and management of the disease.

Rapid optimization of antimicrobial chemotherapy given to pediatric patients with community-acquired pneumonia using PCR techniques with serology and standard culture

Children (n = 117; mean age 2.4 ± 2.9 years) were diagnosed as having community-acquired pneumonia (CAP) using clinical symptoms, chest X-rays, and hematological data. The causative pathogen was determined using real-time polymerase chain reaction (PCR) (6 bacteria), multiple reverse transcription-PCR (MPCR; 11 viruses), bacterial culture, and serology. The initial chemotherapy was evaluated based on the pathogens identified using PCR. We found 27 viral cases (23.1%), 25 bacterial cases (21.4%), 45 mixed infections with virus and bacteria (38.5%), 10 Mycoplasma pneumoniae (8.5%), 7 mixed infections with M. pneumoniae and another pathogen (6.0%), 1 Chlamydophila pneumoniae (0.9%), and 2 unknown pathogens (1.7%). Streptococcus pneumoniae and Haemophilus influenzae accounted for 58 (49.5%) and 27 (23.0%) of the cases, respectively. The median values (50%) of the white blood cell count (WBC) and C-reactive protein (CRP) using the box-and-whisker and plot method, respectively, were 11.7 × 10³ mm⁻³ and 1.4 mg/dl in viral infections, 15.6 × 10³ mm⁻³ and 4.8 mg/dl in mixed infections with virus and bacteria, 17.8 × 10³ mm⁻³ and 6.3 mg/dl in bacterial infections, 6.7 × 10³ mm⁻³ and 1.4 mg/dl in M. pneumoniae infections, and 21.5 × 10³ mm⁻³ and 6.4 mg/dl in mixed infections with M. pneumoniae and other bacterial infections. Sulbactam/ampicillin (n = 61), carbapenems (n = 12), and ceftriaxone (n = 7) were selected for the patients suspected of having bacterial infections alone or mixed infections with bacterial and viruses in accordance with our criteria defined tentatively. For those with M. pneumoniae and C. pneumoniae infections, azithromycin or minocycline was initially used. Treatments averaged 3–5 days. The empirical chemotherapy was improper in 9.4% of cases in relation to the etiologic agents finally identified. We conclude that rapid and comprehensive identification using PCR can provide optimal antimicrobial chemotherapy for CAP patients.

[Clinicoepidemiological characteristics of community-acquired pneumonia in children aged less than 6 years old]

INTRODUCTION

Acute respiratory infections are an important cause of consultations in primary care and hospitals. Most published epidemiological studies have analyzed pneumonia in hospitals and very few include information on primary care.

MATERIAL AND METHODS

We performed a multicenter, prospective, epidemiological study in 17 primary care centers and four hospital pediatric emergency rooms. All children under 6 years of age with a clinical diagnosis of pneumonia were included.

RESULTS

There were 311 patients with a mean age of 32.2 months. The incidence of community-acquired pneumonia was 3,600 cases/100,000 children/year under 6 years old in primary care centers. Of these, 136 were diagnosed in hospitals (43.7 %). The most common clinical signs and symptoms were fever (95.4 %), cough (94.4 %), tachypnea (58.2 %), and auscultation abnormalities (90.2 %). Antibiotic therapy was started in 298 patients (98 %). The most frequent antibiotic was amoxicillin-clavulanate (39.5 %), followed by cefuroxime (32.7 %) and clarithromycin (8.3 %). The most frequently isolated microorganism was respiratory syncytial virus followed by Streptococcus pneumoniae. Hospital admission was required in 15.6 % of patients. Only 24.6 % of the patients had been vaccinated with the heptavalent pneumococcal conjugate vaccine and 12.7 % of the children with underlying respiratory diseases had been vaccinated with the influenza virus vaccine.

CONCLUSIONS

In our milieu, the diagnosis and treatment of community-acquired pneumonia is usually carried out in primary care and the incidence is high. Although most patients do not require hospitalization, etiological diagnosis of community-acquired pneumonia and optimal antibiotic therapy remain difficult goals to achieve.

Infectious etiology modifies the treatment effect of zinc in severe pneumonia

BACKGROUND

Zinc is undergoing evaluation as an inexpensive therapeutic adjuvant for severe pediatric pneumonia.

OBJECTIVE

We explored the effect of etiology on the treatment effect of zinc in young children hospitalized for severe pneumonia.

DESIGN

We analyzed data from a randomized, double-blind, placebo-controlled clinical trial conducted at the Christian Medical College Hospital, a teaching hospital in Tamilnadu, India. Children aged 2-23 mo (n = 299) were randomly assigned to receive a 10-mg tablet of zinc sulfate or placebo twice a day during hospitalization. The primary outcomes were length of hospitalization and time to resolution of severe pneumonia stratified by etiologic classification on the basis of serum C-reactive protein (CRP) concentrations at admission.

RESULTS

CRP concentrations were available for 295 (98.7%) of the enrolled cases. Of these 295 cases, 223 (75.6%) were classified as suspected nonbacterial pneumonias (CRP concentrations <or=40 mg/L). Etiology modified the treatment effect of zinc on the length of the hospital stay [hazard ratio (HR) for interaction term: 0.52; 95% CI: 0.31, 0.91; P = 0.022]. In the 72 suspected bacterial cases (CRP concentrations >40 mg/L), the median length of hospitalization was approximately 20 h longer in the zinc-supplemented group than in the placebo group (87.3 and 68.3 h, respectively; HR: 0.56; 95% CI: 0.34, 0.93; P = 0.025). The treatment effect was not modified in the suspected nonbacterial cases of pneumonia.

CONCLUSIONS

Our results suggest that the treatment effect of zinc for severe pediatric pneumonia may be modified by bacterial infection. Further studies are required to develop appropriate recommendations for the use of zinc in the treatment of severe pneumonia. This trial was registered at clinicaltrials.gov as NCT00198666.

Antimicrobial resistance in Haemophilus influenzae

Haemophilus influenzae is a major community-acquired pathogen causing significant morbidity and mortality worldwide. Meningitis and bacteremia due to type b strains occur in areas where the protein-conjugated type b vaccine is not in use, whereas nontypeable strains are major causes of otitis media, sinusitis, acute exacerbations of chronic bronchitis, and pneumonia. Antibiotic resistance in this organism is more diverse and widespread than is commonly appreciated. Intrinsic efflux resistance mechanisms limit the activity of the macrolides, azalides, and ketolides. beta-Lactamase production is highly prevalent worldwide and is associated with resistance to ampicillin and amoxicillin. Strains with alterations in penicillin binding proteins, particularly PBP3 (beta-lactamase negative ampicillin resistant and beta-lactamase positive amoxicillin-clavulanate resistant), are increasing in prevalence, particularly in Japan, with increasing resistance to ampicillin, amoxicillin, amoxicillin-clavulanate, and many cephalosporins, limiting the efficacy of expanded-spectrum cephalosporins against meningitis and of many oral cephalosporins against other diseases. Most strains remain susceptible to the carbapenems, which are not affected by penicillin binding protein changes, and the quinolones. The activity of many oral agents is limited by pharmacokinetics achieved with administration by this route, and the susceptibility of isolates based on pharmacokinetic and pharmacodynamic parameters is reviewed.

Pneumonien

Pneumonien sind wichtige Verursacher kindlicher Morbidität und in den Entwicklungsländern eine führende Todesursache. Die ätiologische Diagnostik bakterieller Infektionen ist unbefriedigend, die therapeutischen Möglichkeiten bei viralen Pneumonien sehr beschränkt. Klare Möglichkeiten zur Differenzierung der einzelnen Pneumonien fehlen. Für die Behandlung ambulant erworbener Pneumonien orientiert man sich am besten an den zu erwartenden Erregern, die ein gewisse Altersabhängigkeit aufweisen. Amoxicillin und Makrolide stellen die besten, weil zielorientiertesten, Antibiotika für ambulante Pneumonien dar. Angesichts noch relativ günstiger Empfindlichkeitsverhältnisse in mitteleuropäischen Ländern ist nicht primär mit Therapieversagern zu rechnen. Besondere Probleme ergeben sich bei neonatalen Pneumonien sowie bei Pneumonien als Folge von Immunsuppression. Allergisch bedingte Pneumonien müssen gesondert untersucht werden.

Ampicillin and penicillin concentration in serum and pleural fluid of hospitalized children with community-acquired pneumonia

BACKGROUND

Optimal therapeutic efficacy of beta-lactam antibiotics for treatment of pneumococcal pneumonia is thought to be associated with the serum concentration greater than the minimum inhibitory concentration for 40-50% of the interdose interval at site of infection.

OBJECTIVE

Establish whether intravenous administration of ampicillin 400 mg/kg/day or penicillin 200,000 IU/kg/day in 6 divided doses reaches serum and or pleural concentrations above 4 microg/ml for at least 40% of the interdose interval.

MATERIALS AND METHODS

Hospitalized healthy children 1 month-14 years old with community-acquired bacterial pneumonia and empyema were eligible. Blood samples were obtained 30 min (C1) and 3 h (C2) after an antibiotic dose. Pleural fluid samples were obtained 1 and 4 h after the same dose in which blood samples were obtained. The concentrations were measured by high performance liquid chromatography.

RESULTS

The study included 17 patients treated with ampicillin and 13 treated with penicillin. For ampicillin, mean serum concentrations were C1 37.3 +/- 19 microg/ml and C2 11 +/- 10.2 microg/ml and mean pleural fluid concentrations were C1 25.8 +/- 9.9 microg/ml and C2 16.2 +/- 7.9 microg/ml. For penicillin, mean serum concentrations were C1 21.8 +/- 16.4 microg/ml and C2 23.9 +/- 3.4 microg/ml. Mean pleural fluid concentrations were C1 10.9 +/- 2.2 microg/ml and C2 7.7 +/- 3.4 microg/ml. In 8 of 30 patients, serum C2 was <4 microg/ml; in all of them serum concentrations were >4 microg/ml for >40% of the interdose interval.

CONCLUSIONS

This study of the pharmacokinetics of beta-lactam antibiotics in children with bacterial pneumonia may help in the development of therapeutic guidelines for the treatment of pneumococcal pneumonia.

Antimicrobial resistance among pediatric respiratory tract infections: clinical challenges

Considerable development of antimicrobial resistance has occurred in the major pediatric bacterial pathogens, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. However, most of the respiratory infections that children suffer are viral and self-limiting, and only a small percentage of them will develop secondary bacterial infections with the pathogens listed. The challenge for rational antibiotic use is to determine which patients can be treated conservatively and which require antimicrobial intervention to avoid prolonged discomfort or development of permanent sequelae. The basis for rational use of antibiotic in the era of resistance in these major pathogens is to avoid overuse of antimicrobial agents, tailor treatment to identified pathogens as much as possible, and base empiric treatment on the disease being treated and the susceptibility of the probable pathogens at breakpoints based on pharmacokinetic and pharmacodynamic parameters. With appropriate dosing regimens based on these parameters and despite development of resistance, amoxicillin is still one of the most active oral agents against S. pneumoniae and non-beta-lactamase producing strains of H. influenzae, whereas amoxicillin-clavulanate is active against beta-lactamase-producing strains of H. influenzae and M. catarrhalis. Parenteral ceftriaxone and oral and parenteral fluoroquinolones are active against all 3 species, but fluoroquinolones should be used with utmost caution when all other options have been considered because of concerns about toxicity and development of resistance. Introduction of a 7-valent conjugate pneumococcal vaccine in the United States in 2000 reduced the prevalence of invasive pneumococcal disease in children younger than 2 years old, but, as of 2001, had not had a major impact on decreasing antimicrobial resistance.

Paediatric community-acquired pneumonia: current concept in pharmacological control

Community-acquired pneumonia (CAP) is one of the most frequent infections in childhood but it is not easy to establish a rational therapeutic approach for a number of reasons, including difficulties in identifying the aetiology, the fact that the most frequent bacterial pathogens become resistant to commonly used antibiotics and the lack of certain information concerning the possible preventive role of conjugate vaccines. This leads paediatricians to treat almost all cases of CAP with antibiotics, often using a combination of different antimicrobial classes. In order to avoid unnecessary antibiotic use and limit the spread of antibiotic resistance, consensus guidelines for the management of CAP in childhood should be developed and used by practitioners in their offices and hospitals.

Tooth discoloration after treatment with linezolid

With the increasing frequency of methicillin-resistant Staphylococcus aureus in immunocompromised hosts, clinicians are increasingly prescribing the oral treatment option of linezolid. Linezolid is the first of a new class of antibiotics, the oxazolidinones. The drug is generally well tolerated. However, mild-to-moderate adverse effects have been reported, such as gastrointestinal effects (most frequent), myelosuppression, skin eruptions, elevated liver enzymes, and tongue discoloration. As with any new drug on the commercial market, not all adverse effects are elucidated during preclinical trials. An immunocompromised 11-year-old girl with cellulitis of the toe experienced tooth discoloration after receiving a 28-day course of linezolid. The discoloration was present on the enamel of her lower anterior teeth and was superficial and reversible with dental cleaning.