Macrolide resistance: an increasing concern for treatment failure in children

Antigen-specific memory Th17 cells promote cross-protection against nontypeable Haemophilus influenzae after mild influenza A virus infection

Secondary bacterial pneumonia after influenza A virus (IAV) infection is the leading cause of hospitalization and death associated with IAV infection worldwide. Nontypeable Haemophilus influenzae (NTHi) is one of the most common causes of secondary bacterial pneumonia. Current efforts to develop vaccines against NTHi infection focus on inducing antibodies but are hindered by antigenic diversity among NTHi strains. Therefore, we investigated the contribution of the memory T helper type 17 (Th17) response in protective immunity against IAV/NTHi coinfection. We observed that even a mild IAV infection impaired the NTHi-specific Th17 response and increased morbidity and mortality compared with NTHi monoinfected mice. However, pre-existing memory NTHi-specific Th17 cells induced by a previous NTHi infection overcame IAV-driven Th17 inhibition and were cross-protective against different NTHi strains. Last, mice immunized with a NTHi protein that induced a strong Th17 memory response were broadly protected against diverse NTHi strains after challenge with coinfection. These results indicate that vaccination that limits IAV infection to mild disease may be insufficient to eliminate the risk of a lethal secondary bacterial pneumonia. However, NTHi-specific memory Th17 cells provide serotype-independent protection despite an ongoing IAV infection and demonstrate the advantage of developing broadly protective Th17-inducing vaccines against secondary bacterial pneumonia.

Over prescription of antibiotics in children with acute upper respiratory tract infections: A study on the knowledge, attitude and practices of non-specialized physicians in Egypt

BACKGROUND

Antimicrobial resistance (AMR) is currently one of the global public health threats. Increased antibiotic consumption in humans, animals, and agriculture has contributed directly to the spread of AMR. Upper respiratory tract infections (URIs) are one of the most common conditions treated by antibiotics, even if unnecessary as in cases of viral infections and self-limited conditions which represent the most cases of URIs. Investigating physicians' knowledge, attitudes, and practice regarding antibiotic prescriptions in children with acute URIs may reflect the problem of antibiotic over prescription. This study aims to assess the problem in our community and provide information for further planning of appropriate interventions to optimize antibiotic prescriptions.

METHODS

This is a cross-sectional study for all non-specialized physicians dealing with acute upper respiratory tract infections (URIs) in pediatrics sittings in Assiut district, Egypt. We used a self-administered questionnaire to assess physicians' knowledge, attitudes, and practice. In addition, four clinical vignettes addressing different URI scenarios were included in the questionnaire to assess the patterns of antibiotic prescriptions in common cases.

RESULTS

Our study included 153 physicians whose mean age was 32.2 ± 8.7, most of whom were pediatric residents in different health institutes in Assiut district. They had good knowledge as out of the 17 knowledge questions,the mean number of correct answers was 12.4 ± 2.9. Regarding their attitudes, mean attitude scores for inappropriate antibiotic prescribing were low. However, of those scores, the responsibility of others had the highest score (3.8 ± 0.61). Prescribing practice in special conditions of URIs showed that 80% of participants prescribed antibiotics if fever continued for more than five days and 61.4% if the child had a yellowish or greenish nasal discharge. Among 612 clinical vignettes, 326 contained antibiotic prescriptions (53.3%), and appropriate antibiotic prescriptions represented only 8.3% overall.

CONCLUSIONS

Physicians dealing with acute URIs in outpatients' clinics in the Assiut district have good knowledge about antibiotic use and resistance and demonstrate a good attitude toward appropriate antibiotic use. Although the percentage of inappropriate prescriptions in clinical vignettes in high, more research is required to investigate the factors of antibiotic inappropriate prescribing practice and non-adherence to guidelines. Also, it is essential to set up a national antibiotic stewardship program to improve antibiotic prescribing and contain antimicrobial resistance problems.

Widespread of non-typeable Haemophilus influenzae with high genetic diversity after two decades use of Hib vaccine in China

BACKGROUND

The aim of this study was to analyze the microbiological characteristics of nasopharyngeal carriage Haemophilus influenzae isolates collected from children with respiratory infections in Beijing hospital and Youyang Hospital of China.

METHODS

The serotypes of all isolates were determined using latex agglutinated antisera (a-f). The minimum inhibitory concentrations (MICs) of 11 antibiotics were determined using E-test strips. For the beta-lactamase-negative ampicillin-resistant (BLNAR) isolates, ftsI gene was sequenced based on fragments amplified by PCR. STs of H influenzae isolates were determined by multi-locus sequence typing.

RESULTS

The overall carriage rate of H influenzae in the study population was 9.1% (362/3984). One hundred and ninety H influenzae isolates which were selected in our study were non-typeable (NTHi) and 44 (23.2%) of them were positive for β-lactamase. All isolates were susceptible to ceftriaxone and levofloxacin. Susceptibility rates to erythromycin and sulfamethoxazole-trimethoprim in Beijing were significantly higher than Youyang (P < .05). Thirty-six BLNAR isolates were identified. The MLST analysis showed 108 STs in 190 isolates, the most common of which were ST408 (11, 5.8%), ST914 (10, 5.3%), ST57 (9, 4.7%), and ST834 (6, 3.2%). Twelve STs were detected in both of the study sites, which covered 63 isolates.

CONCLUSIONS

All isolates in the present study were NTHi, which suggested widespread of this type in China. The BLNAR isolates were detected more frequently than before. Because high genetic diversity of NTHi isolates of H influenzae exists worldwide, it is important to continuously monitor these bacteria in the future.

Isolation and Antibiotic Susceptibility Testing of Haemophilus influenzae from Nasopharynx of Children under Five Years Attending Maternal and Child Health Clinic in Mbarara Regional Referral Hospital

Background. H. influenzae remains an organism of a major public health challenge worldwide despite the availability of the Hib vaccine, particularly among children under 5 years. Information on the current carriage status and antibiotic susceptibility is key on proper health-care provision. Therefore, we conducted a study to determine H. influenzae carriage rate and antibiotic susceptibility testing of the isolates among the children. Methods. This was a cross-sectional study conducted between January and May 2018, among clinically healthy children under five years attending Maternal and Child Health (MCH) Clinic in Mbarara Regional Referral Hospital (MRRH). We carried out standard microbiology methods to culture, isolate, and identify H. influenzae, and then, we tested for their susceptibility to commonly used antibiotics following the CLSI standards. Results. Of the 248 participants included in the study, 116 (46.77%) were females and 132 (53.23%) males and 78 (31.45%) were below the age of 3 months. Fifty one of the study participants had H. influenzae in their nasopharynx, which represents 20.56% carriage (95% CI 15.49 to 25.63). There was a general high susceptibility of the isolates to the antimicrobial agents commonly used. There was 100% susceptibility to ciprofloxacin and imipenem antibiotic agents, though 6 (11.76%) and 4 (7.84%) of the isolates showed resistance to chloramphenicol and ampicillin, respectively. Conclusion. The high burden presented by H. influenzae and the resultant impact on child health require much attention to prevention of infections associated with the organism. A well-funded molecular study focusing on typing the isolates would determine the impact of the vaccine, given the carriage rates are still high.

Streptococcus pneumoniae and chronic endobronchial infections in childhood

Streptococcus pneumoniae (pneumococcus) is the main cause of bacterial pneumonia worldwide and has been studied extensively in this context. However, its role in chronic endobronchial infections and accompanying lower airway neutrophilic infiltration has received little attention. Severe and recurrent pneumonia are risk factors for chronic suppurative lung disease (CSLD) and bronchiectasis; the latter causes considerable morbidity and, in some populations, premature death in children and adults. Protracted bacterial bronchitis (PBB) is another chronic endobronchial infection associated with substantial morbidity. In some children, PBB may progress to bronchiectasis. Although nontypeable Haemophilus influenzae is the main pathogen in PBB, CSLD and bronchiectasis, pneumococci are isolated commonly from the lower airways of children with these diagnoses. Here we review what is known currently about pneumococci in PBB, CSLD and bronchiectasis, including the importance of pneumococcal nasopharyngeal colonization and how persistence in the lower airways may contribute to the pathogenesis of these chronic pulmonary disorders. Antibiotic treatments, particularly long-term azithromycin therapy, are discussed together with antibiotic resistance and the impact of pneumococcal conjugate vaccines. Important areas requiring further investigation are identified, including immune responses associated with pneumococcal lower airway infection, alone and in combination with other respiratory pathogens, and microarray serotyping to improve detection of carriage and infection by multiple serotypes. Genome wide association studies of pneumococci from the upper and lower airways will help identify virulence and resistance determinants, including potential therapeutic targets and vaccine antigens to treat and prevent endobronchial infections. Much work is needed, but the benefits will be substantial.

Bronchiectasis in Children: Current Concepts in Immunology and Microbiology

Bronchiectasis is a complex chronic respiratory condition traditionally characterized by chronic infection, airway inflammation, and progressive decline in lung function. Early diagnosis and intensive treatment protocols can stabilize or even improve the clinical prognosis of children with bronchiectasis. However, understanding the host immunologic mechanisms that contribute to recurrent infection and prolonged inflammation has been identified as an important area of research that would contribute substantially to effective prevention strategies for children at risk of bronchiectasis. This review will focus on the current understanding of the role of the host immune response and important pathogens in the pathogenesis of bronchiectasis (not associated with cystic fibrosis) in children.

Results from the Survey of Antibiotic Resistance (SOAR) 2011-13 in Turkey

OBJECTIVES

Data are presented from the Survey of Antibiotic Resistance (SOAR) for respiratory tract infection pathogens collected in 2011-13 from Turkey.

METHODS

MICs were determined using Etest(®). Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) interpretive criteria.

RESULTS

Rates of antibiotic susceptibility were very low among 333 isolates of Streptococcus pneumoniae tested: penicillin 38% using CLSI (oral) and EUCAST breakpoints; erythromycin 51% using CLSI and EUCAST criteria; and cefuroxime 64.6% using CLSI and PK/PD and 46.9% using EUCAST. Of the isolates, >90% were susceptible to amoxicillin/clavulanic acid, ceftriaxone (except using EUCAST criteria: 76%), levofloxacin and high-dose intravenous penicillin. Among 339 Haemophilus influenzae isolates, 6.8% were β-lactamase positive while 9.1% were β-lactamase negative but ampicillin resistant (BLNAR) by CLSI (14.7% by EUCAST) criteria. Amoxicillin/clavulanic acid susceptibility was ∼90% by CLSI (with or without BLNAR adjustment, EUCAST and high-dose PK/PD) but lower, at 82.9%, by EUCAST with BLNAR adjustment. Levofloxacin susceptibility was 96% using all three breakpoints. Dramatic differences in rates of susceptibility, depending on the breakpoints used, were seen for cefaclor [94% by CLSI (86.4% BLNAR adjusted), 23% by PK/PD] and cefuroxime [97% by CLSI (89.1% BLNAR adjusted), 85% by PK/PD, 15% by EUCAST (13.0% BLNAR adjusted)]. Streptococcus pyogenes (n = 222) and Moraxella catarrhalis (n = 40) isolates remained highly susceptible to amoxicillin/clavulanic acid, cephalosporins and levofloxacin, with only erythromycin susceptibility dropping below 95% for S. pyogenes.

CONCLUSIONS

Overall, amoxicillin/clavulanic acid and levofloxacin were the most active antibiotics based on all three breakpoints against these pathogens. Although susceptibility was not universally low in Turkey, high resistance rates were found in S. pneumoniae and, when using PK/PD and EUCAST breakpoints, in other respiratory pathogens.

Results from the Survey of Antibiotic Resistance (SOAR) 2011-13 in the Gulf States

OBJECTIVES

To provide surveillance data on the susceptibility of community-acquired respiratory tract isolates from four Gulf and Near East countries from 2011 to 2013.

METHODS

MICs were determined using Etests(®) for all antibiotics evaluated except erythromycin, where testing was by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

Seven hundred and twenty-six respiratory isolates comprising 265 isolates of Streptococcus pneumoniae, 125 isolates of Streptococcus pyogenes and 336 isolates of Haemophilus influenzae were collected from Bahrain, Lebanon, Oman and the United Arab Emirates (UAE). Among S. pneumoniae, susceptibility to penicillin was low in the UAE and Bahrain. Macrolide susceptibility was ∼45%-60% in the UAE and Oman but higher in Lebanon (73.7%) and Bahrain (84%-85%). Penicillin susceptibility using CLSI intravenous breakpoints was >85% in all countries. Antibiotic susceptibility of S. pneumoniae was lower in UAE and Oman. Among S. pyogenes isolates, resistance to erythromycin was highest in Oman (31.6%) but <20% in the other countries. In H. influenzae, susceptibility to most antibiotics was high, except for ampicillin in Lebanon (70.2%) and amoxicillin in Oman (95.4%). Lebanon also had a high percentage (14.9%) of β-lactamase-positive isolates with non-susceptibility to ampicillin. Amoxicillin/clavulanic acid susceptibility was >95% in all countries. Use of EUCAST versus CLSI breakpoints demonstrated profound differences for cefaclor and cefuroxime in S. pneumoniae and H. influenzae, with EUCAST showing lower susceptibility.

CONCLUSIONS

There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.

Results from the Survey of Antibiotic Resistance (SOAR) 2012-14 in Thailand, India, South Korea and Singapore

OBJECTIVES

To provide susceptibility data for community-acquired respiratory tract isolates of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae and Moraxella catarrhalis collected in 2012-14 from four Asian countries.

METHODS

MICs were determined using Etest(®) for all antibiotics except erythromycin, which was evaluated by disc diffusion. Susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints. For macrolide/clindamycin interpretation, breakpoints were adjusted for incubation in CO2 where available.

RESULTS

Susceptibility of S. pneumoniae was generally lower in South Korea than in other countries. Penicillin susceptibility assessed using CLSI oral or EUCAST breakpoints ranged from 21.2% in South Korea to 63.8% in Singapore. In contrast, susceptibility using CLSI intravenous breakpoints was much higher, at 79% in South Korea and ∼95% or higher elsewhere. Macrolide susceptibility was ∼20% in South Korea and ∼50%-60% elsewhere. Among S. pyogenes isolates (India only), erythromycin susceptibility (∼20%) was lowest of the antibiotics tested. In H. influenzae antibiotic susceptibility was high except for ampicillin, where susceptibility ranged from 16.7% in South Korea to 91.1% in India. South Korea also had a high percentage (18.1%) of β-lactamase-negative ampicillin-resistant isolates. Amoxicillin/clavulanic acid susceptibility for each pathogen (PK/PD high dose) was between 93% and 100% in all countries except for H. influenzae in South Korea (62.5%).

CONCLUSIONS

Use of EUCAST versus CLSI breakpoints had profound differences for cefaclor, cefuroxime and ofloxacin, with EUCAST showing lower susceptibility. There was considerable variability in susceptibility among countries in the same region. Thus, continued surveillance is necessary to track future changes in antibiotic resistance.

Microbiological Features of Upper Respiratory Tract Infections in Bulgarian Children for the Period 1998-2014

BACKGROUND

Across the globe, upper respiratory tract infections (URTIs) are the most prevalent cause of morbidity in childhood.

AIMS

The aim of our study is to analyze the incidence and etiology of bacterial URTIs in Bulgarian children, as well as the increasing antimicrobial resistance to the most common etiologic agents over a period of 17 years.

STUDY DESIGN

Retrospective study.

METHODS

The study material comprised the data from 4768 patients (aged 1-16 years) with URTI during the period from 1998-2014. Specific microbiology agent detection was performed by culture examination. Susceptibilities to the investigated pathogens were determined by the disk diffusion method and minimal inhibitory concentration according to the criteria of the Clinical and Laboratory Standards Institute (CLSI). Polymerase chain reaction was used to detect the presence of β-lactam resistance genes.

RESULTS

We identified the following as the most common URTI bacterial pathogens: Streptococcus pneumoniae (40.94%), Streptococcus pyogenes (34.16%), Haemophilus influenzae (44.23%), Moraxella catarrhalis (39.19%) and Staphylococcus aureus (23.88%). In more than 70% of cases, a polymicrobial etiology was found. The most commonly affected individuals were pre-school-aged children, which accounted for more than 36% of all patients. During the study period, a dramatic increase in resistance to antibiotic agents was observed. The most frequent types of resistance were the enzymatic inactivation of penicillins and cephalosporins (close to 100% in staphylococci and moraxellae) and inducible macrolide-lincozamide resistance (about 20% of Gram-positive cocci).

CONCLUSION

Due to mandatory immunization against pneumococci and H. influenzae in Bulgaria and the vast expanding resistance to the most popular antimicrobial agents changes in the etiology of URTI have recently been noted. Regular analysis of this etiological dynamic and the antimicrobial resistance of respiratory pathogens is important for choosing the correct therapy and successful treatment.

Community-acquired Haemophilus influenzae pneumonia--New insights from the CAPNETZ study

OBJECTIVES

We aimed to identify clinical characteristics and to assess effectiveness of different initial antibiotic regimens in adult patients with community-acquired pneumonia (CAP) caused by Haemophilus influenzae.

METHODS

Characteristics were compared between patients with H. influenzae monoinfection versus CAP of other and unknown aetiology enrolled by the German prospective cohort study CAPNETZ. Impact of initial antibiotic treatment on "early clinical response" according to FDA criteria and overall clinical cure were analysed.

RESULTS

H. influenzae was found in 176 out of 2790 patients with pathogen detection (6.3%). Characteristics significantly associated with a H. influenzae CAP (p < 0.017) included purulent sputum, prior pneumococcal vaccination and respiratory co-morbidities. Early clinical response rates on day 4 did not differ between patients receiving any mono- versus combination therapy (85.9% versus 88%), but were numerically higher for regimens including any fluoroquinolone (96.7%) and lower under macrolide monotherapy (70%). Initial CURB-65 score and chronic liver disease were identified as negative predictors for "early clinical response". At day 14, overall clinical cure was 91.9%.

CONCLUSIONS

H. influenzae was a common CAP pathogen, particularly in patients with previous pneumococcal vaccination and respiratory co-morbidities. Severity of illness and chronic liver disease were associated with a lower rate of "early clinical response".

Prevalence of antibiotic use for pediatric acute upper respiratory tract infections in Korea

This study was conducted to estimate the prevalence of antimicrobial prescribing for acute upper respiratory tract infections (URI) among pediatric outpatients and to identify the national patterns of its use from 2009 to 2011 in Korea. Using National Patients Sample database from 2009 to 2011, we estimated the frequency of antibiotics prescribing for URI in pediatric outpatients with diagnoses of acute nasopharyngitis (common cold), acute sinusitis, acute pharyngitis, acute tonsillitis, acute laryngitis/tracheitis, acute obstructive laryngitis/epiglottitis, and acute upper respiratory infections of multiple and unspecified sites. The proportions of each antibiotic class were calculated by year and absolute and relative differences were estimated. Also, we investigated daily amount of prescribed antibiotics per defined population according to the type of medical care institution, physician specialty, and geographic region. The overall antibiotic prescribing proportion was 58.7% and its annual proportion slightly decreased (55.4% in 2011 vs. 60.5% in 2009; adjusted odds ratio, 0.82; 95% confidence interval, 0.82-0.83). Variations by the type of medical care institution were observed. Tertiary hospitals (45.0%) were less likely to prescribe antibiotics than primary care clinics (59.4%), hospitals (59.0%), and general hospitals (61.2%); they showed different tendencies in choosing antibiotics. Variations by physician specialty and region were also observed. Prevalence of antimicrobial prescribing for pediatric URI is still considered higher than that of western countries and varies by the type of medical care institution, physician specialty, and geographic region.

Macrolide-resistant Streptococcus pyogenes: prevalence and treatment strategies

Although penicillin remains the first-choice treatment for Streptococcus pyogenes infection, macrolides are important alternatives for allergic patients and lincosamides are recommended together with β-lactams in invasive infections. S. pyogenes may exhibit macrolide resistance because of active efflux (mef genes) or target modification (erm genes), the latter conferring cross resistance to lincosamides and streptogramin B. Worldwide, resistance is restricted to a limited number of genetic lineages, despite resistance genes being encoded on mobile genetic elements. For reasons that are not completely clear, resistance and the associated phenotypes are highly variable across countries. Although resistance remains high in several countries, particularly in Asia, an overall decreasing trend of resistance has been noted in recent years, mostly in Europe. This decrease is not always accompanied by declines in macrolide consumption, suggesting significant roles of other factors in determining the dynamics of macrolide-resistant clones. Continued surveillance is needed to obtain further insights into the forces governing macrolide resistance in S. pyogenes.

Nasopharyngeal carriage and antimicrobial susceptibility of Haemophilus influenzae among children younger than 5 years of age in Beijing, China

Background

Haemophilus influenzae is one of the main pathogens that cause community-acquired respiratory infections in children. Our previous study showed that H. influenzae is the second most common pathogen causing pneumonia and accounts for 30–50% of bacterial meningitis among Chinese children. H. influenzae carriage in children and its resistance to commonly used antimicrobials varies widely both geographically and over time.

Results

Surveys of the nasopharyngeal carriage of H. influenzae in children younger than 5 years of age with acute respiratory tract infection (ARI) were conducted in Beijing Children’s Hospital, China in 2000, 2002, 2010, and 2012. The overall annual carriage rates of H. influenzae among children younger than 5 years of age with ARI were 35.5%, 20.6%, 14.4%, and 18.7%, and the percentages of H. influenzae isolates producing β-lactamase were 4%, 13%, 27.1%, and 31%, respectively. The percentages of susceptibility to ampicillin progressively decreased from 96% (2000) to 87% (2002) to 63% (2010) to 61% (2012). All of the ampicillin-resistant isolates were found to be beta-lactamase producers. The susceptibility to tetracycline increased from 54% (2000) to 60% (2002) to 91.5% (2010) to 94.5% (2012). No statistically significant differences were observed in the susceptibility to cefaclor, cefuroxime, sulfamethoxazole, and chloramphenicol. Amoxicillin/clavulanic acid and ceftriaxone were the most effective antimicrobials for the isolates of H. influenzae across the 10-year period.

Conclusions

This report on the H. influenzae carriage rates in children and the susceptibility of these bacteria to commonly used antibiotics showed that H. influenzae carriage decreased from 2000 to 2012. Additionally, the percentage of β-lactamase-producing isolates increased while their susceptibility to ampicillin progressively decreased during this time. These results indicate that the appropriate empirical antimicrobial therapy should be changed for pediatric patients in China.

Pediatric acute-onset neuropsychiatric syndrome

Whether some instances of obsessive-compulsive disorder are secondary to infectious and/or autoimmune processes is still under scientific debate. The nosology has undergone an iterative process of criteria and acronyms from PITANDS to PANDAS to PANS (or CANS for neurology). This review focuses on the clinical presentation, assessment, proposed pathophysiology, and treatment of pediatric autoimmune neuropsychiatric disorders associated with streptococcus (PANDAS), and the newest iteration, pediatric acute-onset neuropsychiatric syndrome (PANS). Children who have these symptoms, which have become known as PANS, have been described by their parents as "changed children."

Assessment of Bronchial Lavage Samples For the Diagnosis of Childhood Pneumonia

Background: Lower respiratory tract infections are frequent and often serious diseases in children. Wide number of microorganisms may cause lower respiratory tract infections, and sometimes it could be very difficult to determine the exact causative.Aim: The aim of this study was to assess the reliability of specimens obtained by bronchial lavage in determining the etiology of childhood pneumonia.Methods: This is prospective study conducted during four years period, in a group of 60 children aged from 6 months to 18 years. All patients included in this study underwent bronchoscopy when they fulfilled criteria of routine clinical protocol, in order to set correct diagnosis of lower respiratory tract disease. Results of bacteriological analysis of PLA samples were compared against the results of bacteriological analysis of BL samples of the same patient.Results: In majority of subjects - 41 (68.32%), the bacteria isolated from the bronchial lavage samples was not identified in pharyngolaryngeal aspirate and was considered as the cause of infection. Haemophilus influenzae was the most frequently isolated pathogen in bronchial lavage samples.Conclusion: Findings based on analysis of bronchial lavage samples may be used as reliable criterion for etiological diagnosis in cases of pneumonia when initial empirical treatment failed.

Azithromycin: mechanisms of action and their relevance for clinical applications

Azithromycin is a macrolide antibiotic which inhibits bacterial protein synthesis, quorum-sensing and reduces the formation of biofilm. Accumulating effectively in cells, particularly phagocytes, it is delivered in high concentrations to sites of infection, as reflected in rapid plasma clearance and extensive tissue distribution. Azithromycin is indicated for respiratory, urogenital, dermal and other bacterial infections, and exerts immunomodulatory effects in chronic inflammatory disorders, including diffuse panbronchiolitis, post-transplant bronchiolitis and rosacea. Modulation of host responses facilitates its long-term therapeutic benefit in cystic fibrosis, non-cystic fibrosis bronchiectasis, exacerbations of chronic obstructive pulmonary disease (COPD) and non-eosinophilic asthma. Initial, stimulatory effects of azithromycin on immune and epithelial cells, involving interactions with phospholipids and Erk1/2, are followed by later modulation of transcription factors AP-1, NFκB, inflammatory cytokine and mucin release. Delayed inhibitory effects on cell function and high lysosomal accumulation accompany disruption of protein and intracellular lipid transport, regulation of surface receptor expression, of macrophage phenotype and autophagy. These later changes underlie many immunomodulatory effects of azithromycin, contributing to resolution of acute infections and reduction of exacerbations in chronic airway diseases. A sub-group of post-transplant bronchiolitis patients appears to be sensitive to azithromycin, as may be patients with severe sepsis. Other promising indications include chronic prostatitis and periodontitis, but weak activity in malaria is unlikely to prove crucial. Long-term administration of azithromycin must be balanced against the potential for increased bacterial resistance. Azithromycin has a very good record of safety, but recent reports indicate rare cases of cardiac torsades des pointes in patients at risk.

Geographic and temporal trends in antimicrobial nonsusceptibility in Streptococcus pneumoniae in the post-vaccine era in the United States

BACKGROUND

We examined whether observed increases in antibiotic nonsusceptible nonvaccine serotypes after introduction of pneumococcal conjugate vaccine in the United States in 2000 were driven primarily by vaccine or antibiotic use.

METHODS

 Using active surveillance data, we evaluated geographic and temporal differences in serotype distribution and within-serotype differences during 2000-2009. We compared nonsusceptibility to penicillin and erythromycin by geography after standardizing differences across time, place, and serotype by regressing standardized versus crude proportions. A regression slope (RS) approaching zero indicates greater importance of the standardizing factor.

RESULTS

 Through 2000-2006, geographic differences in nonsusceptibility were better explained by within-serotype prevalence of nonsusceptibility (RS 0.32, 95% confidence interval [CI], .08-.55 for penicillin) than by geographic differences in serotype distribution (RS 0.71, 95% CI, .44-.97). From 2007-2009, serotype distribution differences became more important for penicillin (within-serotype RS 0.52, 95% CI, .11-.93; serotype distribution RS 0.57, 95% CI, .14-1.0).

CONCLUSIONS

 Differential nonsusceptibility, within individual serotypes, accounts for most geographic variation in nonsusceptibility, suggesting selective pressure from antibiotic use, rather than differences in serotype distribution, mainly determines nonsusceptibility patterns. Recent trends suggest geographic differences in serotype distribution may be affecting the prevalence of nonsusceptibility, possibly due to decreases in the number of nonsusceptible serotypes.

Differences in the frequency of 23S rRNA gene mutations in Mycoplasma pneumoniae between children and adults with community-acquired pneumonia: clinical impact of mutations conferring macrolide resistance

We investigated the frequency and clinical significance of macrolide resistance in adult and pediatric patients with community-acquired pneumonia from a Mycoplasma pneumoniae infection. The frequency of the A2063G mutation in the 23S rRNA gene was significantly higher in children than in adults (61.3% [19/31] and 13.3% [8/60], respectively; P < 0.001). Patients with macrolide-resistant M. pneumoniae infections showed a longer duration of fever (P = 0.021) and required a longer duration of antibiotic treatment (P = 0.007).

Psychotropic effects of antimicrobials and immune modulation by psychotropics: implications for neuroimmune disorders

Antimicrobial compounds and psychotropic medications often share overlapping mechanisms of actions and pharmacological effects. The immune system appears to be an important site of interaction as several antimicrobials display neurological and, at times, direct psychotropic effects, while psychotropics have shown significant immunomodulatory properties. The isoniazid class of antibiotics for example has been shown to possess monoamine oxidase activity, while selective serotonin reuptake inhibitors have shown significant effects on leukocyte populations. As the importance of the immune system's role in CNS homeostasis and disease continues to move to the forefront of neuropsychiatric research, these shared pharmacological effects may provide an important insight, elucidating the complexities in neuroimmune pathophysiology and guiding the development of potential treatments.

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.

Antibacterial agents in pediatrics

Antibiotics are among the most frequently used drugs in children. Although antibacterials have been available for decades, many agents have not been studied to assess their safety and efficacy in the pediatric population. This article describes the pharmacologic characteristics and therapeutic use of the most commonly prescribed antibacterials for pediatric patients. Newer agents currently under clinical investigation are discussed as well.

Antimicrobial susceptibility of Haemophilus influenzae strains and antibiotics usage patterns in pediatric outpatients: results from a children's hospital in China (2000-2004)

OBJECTIVE

To investigate the nasopharyngeal carriage and antimicrobial susceptibility of H. influenzae among children younger than 5 years old and to assess antibiotics usage patterns in the outpatient department of Beijing Children's Hospital from 2000 to 2004.

MATERIALS AND METHODS

From 2000 to 2004, At least 100 strains of H. influenzae were isolated from the pediatric patients who were younger than 5 years and who presented with symptoms of acute upper respiratory tract infections during February to May in each of the study years. Antimicrobial susceptibilities were determined; and antibiotics usage was expressed as defined daily dose (DDD)/100 patient days.

RESULTS

The overall nasopharyngeal carriage rate of H. influenzae is 26.3% (562/2,137) in children younger than 5 years old with acute upper respiratory tract infection. The percentage of ampicillin-resistant isolates ranges from 4.0% (4/100) to 14.3% (17/119) from 2000 to 2004. All the ampicillin-resistant isolates are beta-lactamase producers. More than 80% of the isolates are susceptible to amoxicillin, cefaclor, and chloramphenicol; whereas, almost all (99-100%) of the isolates are sensitive to amoxicillin/clavulanic acid, ceftriaxone, and cefuroxime. For antibiotics utilization, macrolides are the predominantly used antibiotics, followed by cephalosporins and penicillins among pediatric patients in the outpatient department during the study period.

CONCLUSION

All amoxicillin-resistant isolates of H. influenzae are producing beta-Lactamase; and the rates of amoxicillin-resistant isolates are increasing over time. Amoxicillin/clavulanic acid and cephalosporins are highly sensitive to H. influenzae isolated from Chinese pediatric patients. Macrolides are the most used antibiotics in the outpatient department during the study period.

Comparative activities of antibiotics against intracellular non-typeable Haemophilus influenzae

INTRODUCTION

Non-typeable Haemophilus influenzae (NTHi) is a major bacterial pathogen of community-acquired respiratory tract infection and is usually found extracellularly, although studies have revealed that NTHi may possess the ability to invade human epithelial cells where it is then protected against attack by the local immune system and partly against the effect of antibiotics. The aim of the present study was to assess the ability of ampicillin, azithromycin, telithromycin, ciprofloxacin and moxifloxacin, five antibiotics in common clinical use, to kill NTHi within bronchial epithelial cells.

METHODS

Confluent human bronchial epithelial cells were infected with NTHi 77, a particularly invasive clinical strain. Extracellular bacterial cells were killed with gentamicin and the intracellular bacteria were incubated with antibiotics at concentrations of 1 mg/l or 10 mg/l for 4 h or 8 h. Viable intracellular bacteria were counted after lysis of the epithelial cells.

RESULTS

With the exception of ampicillin, all the antibiotics caused significant reduction of intracellular bacteria at concentrations of 10 mg/l and exposure for 4 h or at 1 mg/l for 8 h. At 1 mg/l, moxifloxacin eliminated 94% of intracellular NTHi after 4 h and 98% after 8 h; ciprofloxacin, azithromycin and telithromycin only achieved killing indices below 75 after 4 h but 86-90% killing after 8 h. At 10 mg/l, moxifloxacin, ciprofloxacin, telithromycin and azithromycin were able to achieve 99.7%, 96.3%, 86.7% and 74.7% eradication of intracellular bacteria, respectively, after exposure for 4 h.

CONCLUSION

These results demonstrate the rapid antibacterial efficacy of moxifloxacin against intracellular NTHi in vitro. Moxifloxacin, which combines high extracellular and intracellular activities, could be an important tool in the treatment of recurrent respiratory tract infections.

In vitro antibacterial activities of tigecycline and comparative agents by time-kill kinetic studies in fresh Mueller-Hinton broth

Time-kill kinetics performed with tigecycline, in fresh MHB, demonstrated a consistent 1 to 2 log(10) CFU/ml reduction in bacterial counts against the majority of clinically relevant pathogens tested. Although classified as a bacteriostatic agent, tigecycline shows bactericidal activity against select isolates associated with serious infection. In general, vancomycin and imipenem demonstrated bactericidal activity.

Pneumolysin polymerase chain reaction for diagnosis of pneumococcal pneumonia and empyema in children

Streptococcus pneumoniae is the most important cause of childhood pneumonia and empyema, yet the diagnosis of pneumococcal infections by conventional methods is challenging. In this study, the clinical value of the pneumolysin-targeted real-time polymerase chain reaction (PCR) method for the diagnosis of pneumococcal pneumonia and empyema was evaluated with 33 whole blood samples and 12 pleural fluid samples. The analytical sensitivity of the PCR assay was 4 fg of pneumococcal DNA, corresponding to two genome equivalents of pneumococcal DNA per reaction. The PCR assay correctly detected all clinical isolates of S. pneumoniae tested, whereas all nonpneumococcal bacterial organisms tested were negative by PCR. In a clinical trial, S. pneumoniae was detected by PCR in the pleural fluid of 75% of children with empyema, increasing the detection rate of pneumococcus almost tenfold that of pleural fluid culture. However, in whole blood samples, PCR detected S. pneumoniae in only one child with pneumonia and one child with pneumococcal empyema and failed to detect S. pneumoniae in three children with blood cultures positive for S. pneumoniae. The present data indicate that pneumolysin-targeted real-time PCR of pleural fluid is a valuable method for the etiologic diagnosis of pneumococcal empyema in children. The ease and rapidity of the LightCycler technology (Roche Diagnostics, Mannheim, Germany) make real-time PCR an applicable tool for routine diagnostics. In the evaluation of blood samples, blood culture remains the superior method for the diagnosis of bacteremic pneumococcal disease.

The search for new antimicrobials: why we need new options

The increasing identification of antibiotic-resistant pathogens that cause serious infections cannot be ignored. Although the future cannot be predicted with certainty, it is surely possible that an extensive epidemic of resistant bacterial infections could potentially harm millions of people. Given that it takes more than 10 years to establish the efficacy and safety of new compounds, there is an urgent need to restock the antibiotic pipeline. Only a few new antibacterial agents have received approval by the US Food and Drug Administration in the last 5 years, including linezolid in 2001, cefditoren, pivoxil and ertapenem in 2002, gemifloxacin and daptomycin in 2003, and telithromycin in 2004. Many of these agents are improved derivatives from established classes of antibiotics, and several are directed primarily at resistant Gram-positive bacteria (e.g., linezolid and daptomycin). One promising new addition is the recent approval of tigecycline (Tigacyl, Wyeth) in June 2005.

Antibiotics in childhood pneumonia

Pneumonia is one of the most common global childhood illnesses. The diagnosis relies on a combination of clinical judgement and radiological and laboratory investigations. Streptococcus pneumoniae remains the most important cause of childhood community-acquired pneumonia. In addition, viruses (including respiratory syncytial virus) and atypical bacteria (Mycoplasma and Chlamydia) are likely pathogens in younger and older children in developed countries. In the minority of cases only, the actual organism is isolated to guide treatment. Antibiotics effective against the expected bacterial pathogens should be instituted where necessary. The route and duration of antibiotic therapy, the role of emerging pathogens and the impact of pneumococcal resistance and conjugate pneumococcal vaccines are also discussed.

Antibiotic resistance patterns among respiratory pathogens at a German university children's hospital over a period of 10 years

Growing antimicrobial resistance among Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis is raising major concern worldwide. Strains of S. pneumoniae, H. influenzae and M. catarrhalis isolated from children with respiratory tract as well as invasive infection in a South-Western region of Germany between 1993 and 2002 were tested for susceptibility to common antibiotics including penicillins, cephalosporins and macrolides. A total of 2,362 S. pneumoniae, 2,501 H. influenzae, and 1,982 M. catarrhalis isolates were tested. Only two S. pneumoniae strains were found to be highly resistant to penicillin. The overall rate of intermediate resistance to penicillin was 3.5%. There was a significant increase in erythromycin resistance from 5% in 1993 to 12.2% in 2002 (P=0.001). No increase in ampicillin resistance was observed for H. influenzae over time. The rate of cefaclor resistance, however, increased from 4.5% to 11.8% (P<0.0001). Furthermore, a massive increase in erythromycin resistance from 26% to 40% was observed (P<0.0001). The vast majority of M. catarrhalis isolates were beta-lactamase positive, the minimal inhibitory concentration to ampicillin, however, exceeded only in 3% of all strains the cut-off of 1.5 mg/l. The erythromycin resistance rate of M. catarrhalis was 0.3%.

CONCLUSION

There is still a low rate of penicillin/ampicillin resistance in S. pneumoniae, and H. influenzae, but an alarming increase in resistance to erythromycin, and in H. influenzae a significant increase in cefaclor resistance was observed over the 10-year period in South-Western Germany.

In vivo efficacies and pharmacokinetics of DX-619, a novel des-fluoro(6) quinolone, against Streptococcus pneumoniae in a mouse lung infection model

DX-619 is a novel des-fluoro(6) quinolone with potent activity against gram-positive pathogens. The in vivo activity of DX-619 against Streptococcus pneumoniae was compared with those of fluoro(6) quinolones, sitafloxacin, and ciprofloxacin in a mouse model. Two strains of S. pneumoniae were used: a penicillin-sensitive S. pneumoniae (PSSP) strain and a penicillin-resistant S. pneumoniae (PRSP) strain. Furthermore, these strains showed intermediate susceptibilities to ciprofloxacin. In murine lung infections caused by PSSP, the 50% effective doses (ED50s) of DX-619, sitafloxacin, and ciprofloxacin were 9.15, 11.1, and 127.6 mg/kg of body weight, respectively. Against PRSP-mediated pneumonia in mice, the ED50s of DX-619, sitafloxacin, and ciprofloxacin were 0.69, 4.84, and 38.75 mg/kg, respectively. The mean +/- standard error of the mean viable bacterial counts in murine lungs infected with PSSP and treated with DX-619, sitafloxacin, ciprofloxacin (10 mg/kg twice daily), and saline (twice daily) were 1.75 +/- 0.06, 1.92 +/- 0.23, 6.48 +/- 0.28, and 7.57 +/- 0.13 log10 CFU/ml, respectively. Furthermore, the numbers of viable bacteria in lungs infected with PRSP and treated with the three agents and not treated (control) were 1.73 +/- 0.04, 2.28 +/- 0.17, 4.61 +/- 0.59, and 5.54 +/- 0.72 log10 CFU/ml, respectively. DX-619 and sitafloxacin significantly decreased the numbers of viable bacteria in the lungs compared to the numbers in the lungs of ciprofloxacin-treated and untreated mice. The pharmacokinetic parameter of the area under the concentration-time curve (AUC)/MIC ratio in the lungs for DX-619, sitafloxacin, and ciprofloxacin were 171.0, 21.92, and 1.22, respectively. The AUC/MIC ratio in the lungs was significantly higher for DX-619 than for sitafloxacin and ciprofloxacin. Our results suggest that DX-619 and sitafloxacin are potent against both PSSP and PRSP in our mouse pneumonia model.

Properties of novel international drug-resistant pneumococcal clones identified in day-care centers of Lisbon, Portugal

In this study, 61 drug-resistant Streptococcus pneumoniae strains were characterized by multilocus sequence typing (MLST). These strains were representatives of 26 major clones (defined using pulsed-field gel electrophoresis) accounting for 93% of the 1,285 drug-resistant Streptococcus pneumoniae isolates recovered from the nasopharynges of healthy children attending day-care centers in Lisbon during 2001 to 2003. Using MLST, 13 of the 26 clones were found to be identical or closely related to 11 Pneumococcal Molecular Epidemiology Network (PMEN) clones, 4 clones were found to be unique as there were no identical or highly related allelic profiles deposited in the MLST database, and the remaining 9 clones had sequence types that matched or differed at a single or double locus from allelic profiles available in the MLST database. These nine clones were of serotypes 33F, 10A, 19A, 19F, 6A, 20, 24F, and 3, one was nontypeable, and, by MLST, they were found to be identical or highly related to isolates from disease origin that were dispersed internationally. Since the majority of these clones had serotypes that are not included in the 7-valent conjugate pneumococcal vaccine, monitoring of these clones is important for surveying their possible spread in the future. We propose the inclusion of these novel international clones in the PMEN.

The Sentinel Project: an update on the prevalence of antimicrobial resistance in community-acquired respiratory Streptococcus pneumoniae and Haemophilus spp. in Italy

A total of 460 Streptococcus pneumoniae and Haemophilus spp. collected from respiratory infections during 2000 was tested for their susceptibility to 15 selected antibiotics. Overall, penicillin resistance among pneumococci was 10.5%, while lack of susceptibility to macrolides, co-trimoxazole, tetracycline and chloramphenicol reached 35.2%, 26.2%, 22.6% and 6.0%, respectively. Amoxicillin/clavulanic acid and levofloxacin were the most potent compounds (100% and 99.9% susceptible strains, respectively). Among isolates of Haemophilus influenzae and Haemophilus parainfluenzae, beta-lactamase production (12.5% and 10%, respectively), and co-trimoxazole (19.9% and 40.0%) and clarithromycin (11.2% and 40.0%) resistance were the prevalent threats. This study confirms the trend observed in Italy since 1992: macrolide resistance among respiratory microorganisms is increasing, while several drugs including amoxicillin/clavulanic acid, third generation injectable cephalosporins and fluoroquinolones remain active on the great majority of these pathogens.

Efflux-mediated antimicrobial resistance

Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.

Pediatric sinusitis: when do we operate?

PURPOSE OF REVIEW

The role of surgery in the treatment of pediatric sinusitis is still in evolution. This review of recent literature highlights developments in the study of pediatric sinusitis, particularly as it pertains to surgical intervention.

RECENT FINDINGS

There is growing support in the literature for adenoidectomy as a first-line surgical intervention for chronic rhinosinusitis in children when maximal medical management fails. Maxillary sinus aspiration or middle meatal culture can be performed at the same sitting to facilitate directed antibiotic therapy. Intravenous antibiotics seem to be a promising alternative to functional endoscopic sinus surgery (FESS), especially in younger children. Current literature continues to support FESS as a safe and effective treatment for pediatric sinus disease. Previous notions that FESS may inhibit midfacial growth have been challenged by several recent studies. There is no clear consensus regarding timing of FESS for chronic rhinosinusitis. However, the current literature seems to support FESS when maximal medical therapy, adenoidectomy, and culture-directed systemic antibiotics have all failed with persistence of sinonasal disease, when anatomic abnormalities predispose to chronic rhinosinusitis by obstructing normal sinonasal drainage pathways, in sinonasal polyposis to facilitate application of topical steroids, as an adjunct to desensitization in aspirin-sensitive patients, when orbital or intracranial complications of sinonasal disease occur, and in selected cystic fibrosis patients to improve quality of life and facilitate application of topical antibiotics with activity against Pseudomonas aeruginosa.

SUMMARY

Although the current literature lends some additional clarity to the indications for surgical intervention in pediatric chronic rhinosinusitis, additional research is still needed to elucidate appropriate timing for surgery and more specific indications.

Trends of penicillin and erythromycin resistance among invasive Streptococcus pneumoniae in Europe

OBJECTIVES

To forecast trends in resistance to penicillin and erythromycin among Streptococcus pneumoniae in Europe.

METHODS

Since 1999, the European Antimicrobial Resistance Surveillance System (EARSS) has collected routine antimicrobial susceptibility test results of S. pneumoniae. To observe and predict changes of reduced susceptibility over time, we used a multinomial logistic regression model.

RESULTS

Large variations in penicillin and erythromycin non-susceptibility were observed between countries, and reduced susceptibility to erythromycin (17%) has become more frequent than reduced susceptibility to penicillin (10%) in Europe overall. An overall decrease in single penicillin non-susceptibility, but an increase in dual non-susceptibility was observed, indicating a shift of single penicillin to combined non-susceptibility with erythromycin. By 2006, the proportion of single erythromycin and dual non-susceptibility could increase to as much as 20.4% and 8.9%, respectively.

CONCLUSIONS

Our results indicate that appropriately dosed beta-lactams for empirical therapy are still the treatment of choice, and that macrolides should be used with prudence.

Pediatric chronic rhinosinusitis

PURPOSE OF REVIEW

Pediatric sinusitis is prevalent, and the debate continues regarding how best to care for these children. Although acute sinusitis is commonly associated with an upper respiratory infection, the focus of this paper is on chronic rhinosinusitis in children. Research is often more difficult in children than adults, so many times one can learn from the adult literature and determine whether there can be application to the childhood population.

RECENT FINDINGS

This paper looks at both medical and surgical treatment of chronic rhinosinusitis. "Maximal medical management" is often cited in the literature, but what this should consist of has never been clearly proved in the literature. Alternative medicine approaches as well as irrigation as an adjunct to care are discussed. Biomaterials are also be discussed. Recent outcome data are put in perspective.

SUMMARY

Hopefully the reader will find the presentation stimulating. The paper does not promote surgery as a "cure all," and in the end, analysis will hopefully leave the reader more cautious but with a better understanding of this complex disease.

Molecular characterisation of macrolide resistance mechanisms of Streptococcus pneumoniae and Streptococcus pyogenes isolated in Germany, 2002-2003

In the present study, a real-time PCR protocol was developed for the detection of macrolide resistance determinants and was validated in a nationwide study in Germany covering a total of 236 Streptococcus pyogenes and 241 Streptococcus pneumoniae strains collected from children < or = 16 years of age with community-acquired infections. Macrolide resistance was observed in 19.9% of pneumococcal strains and 14% of S. pyogenes isolates. Of the erythromycin A-resistant S. pyogenes strains, 93.9% showed the efflux type mef(A); 62.5% of the S. pneumoniae strains were mef(A)- and 37.5% erm(B)-positive. The correlation of the results of real-time PCR assay genotyping in the present study compared with those of conventional PCR genotyping and resistance phenotyping was 100%. Macrolide resistance is of growing concern in Germany. This highly sensitive and specific PCR assay to detect macrolide resistance has the potential to provide sufficiently rapid results to improve antibiotic treatment of streptococcal infections.

Antibacterial agents in pediatrics

Antibiotics are among the most widely prescribed therapeutic agents in children. Several new trends in antibiotic usage for pediatric care have emerged. New mechanisms of antibacterial resistance have required a broader repertoire of antibiotic usage, including new agents directed at multidrug resistance. After promotion of judicious antibiotic use, there has been a decline in the number of pediatric prescriptions for antibiotics. Recent legislation addresses the necessity for pediatric clinical drug trials, ensuring development of further antibacterial agents for use in pediatric patients.