Increase in pneumococcus macrolide resistance, United States

Antibiotic prescription for outpatients with influenza and subsequent hospitalisation: A cohort study using insurance data

Background

Whether prophylactic administration of antibiotics to patients with influenza reduces the hospitalisation risk is unknown. We aimed to examine the association between antibiotic prescription in outpatients with influenza infection and subsequent hospitalisation.

Methods

We conducted a cohort study using health insurance records of Japanese clinic and hospital visits between 2012 and 2016. Participants were outpatients (age, 0-74 years) with confirmed influenza infection who were prescribed anti-influenza medicine. The primary outcomes were the hospitalisation risk from all causes and pneumonia and the duration of hospitalisation due to pneumonia.

Results

We analysed 903,104 outpatient records with 2469 hospitalisations. The risk of hospitalisation was greater in outpatients prescribed anti-influenza medicine plus antibiotics (0.31% for all causes and 0.18% for pneumonia) than in those prescribed anti-influenza medicine only (0.27% and 0.17%, respectively). However, the risk of hospitalisation was significantly lower in patients prescribed peramivir and antibiotics than in those prescribed peramivir only. Patients who received add-on antibiotics had a significantly longer hospital stay (4.12 days) than those who received anti-influenza medicine only (3.77 days). In all age groups, the hospitalisation risk from pneumonia tended to be greater in those who received antibiotics than in those prescribed anti-influenza medicine only. However, among older patients (65-74 years), those provided add-on antibiotics had an average 5.24-day shorter hospitalisation due to pneumonia than those provided anti-influenza medicine only (not significant).

Conclusions

In outpatient cases of influenza, patients who are prescribed antibiotics added to antiviral medicines have a higher risk of hospitalisation and longer duration of hospitalisation due to pneumonia.

Solithromycin in Children and Adolescents With Community-acquired Bacterial Pneumonia

BACKGROUND

Solithromycin is a new macrolide-ketolide antibiotic with potential effectiveness in pediatric community-acquired bacterial pneumonia (CABP). Our objective was to evaluate its safety and effectiveness in children with CABP.

METHODS

This phase 2/3, randomized, open-label, active-control, multicenter study randomly assigned solithromycin (capsules, suspension or intravenous) or an appropriate comparator antibiotic in a 3:1 ratio (planned n = 400) to children 2 months to 17 years of age with CABP. Primary safety endpoints included treatment-emergent adverse events (AEs) and AE-related drug discontinuations. Secondary effectiveness endpoints included clinical improvement following treatment without additional antimicrobial therapy.

RESULTS

Unrelated to safety, the sponsor stopped the trial prior to completion. Before discontinuation, 97 participants were randomly assigned to solithromycin (n = 73) or comparator (n = 24). There were 24 participants (34%, 95% CI, 23%-47%) with a treatment-emergent AE in the solithromycin group and 7 (29%, 95% CI, 13%-51%) in the comparator group. Infusion site pain and elevated liver enzymes were the most common related AEs with solithromycin. Study drug was discontinued due to AEs in 3 subjects (4.3%) in the solithromycin group and 1 (4.2%) in the comparator group. Forty participants (65%, 95% CI, 51%-76%) in the solithromycin group achieved clinical improvement on the last day of treatment versus 17 (81%, 95% CI, 58%-95%) in the comparator group. The proportion achieving clinical cure was 60% (95% CI, 47%-72%) and 68% (95% CI, 43%-87%) for the solithromycin and comparator groups, respectively.

CONCLUSIONS

Intravenous and oral solithromycin were generally well-tolerated and associated with clinical improvement in the majority of participants treated for CABP.

Antibiotic Prescription Patterns in the Paediatric Primary Care Setting before and after the COVID-19 Pandemic in Italy: An Analysis Using the AWaRe Metrics

The containment measures following COVID-19 pandemic drastically reduced airway infections, but they also limited the access of patients to healthcare services. We aimed to assess the antibiotic prescription patterns in the Italian paediatric primary care setting before and after the containment measures implementation. For this retrospective analysis, we used a population database, Pedianet, collecting data of patients aged 0–14 years enrolled with family paediatricians (FP) from March 2019 to March 2021. Antibiotic prescriptions were classified according to WHO AWaRe classification. An interrupted time series evaluating the impact of the containment measures implementation on the monthly antibiotic index, on the access to watch index, and on the amoxicillin to co-amoxiclav index stratified by diagnosis was performed. Overall, 121,304 antibiotic prescriptions were retrieved from 134 FP, for a total of 162,260 children. From March 2020, the antibiotic index dropped by more than 80% for respiratory infections. The Access to Watch trend did not change after the containment measures, reflecting the propensity to prescribe more broad-spectrum antibiotics for respiratory infections even during the pandemic. Similarly, co-amoxiclav was prescribed more often than amoxicillin alone for all the diagnoses, with a significant variation in the trend slope for upper respiratory tract infections prescriptions.

Macrolide Treatment Failure due to Drug–Drug Interactions: Real-World Evidence to Evaluate a Pharmacological Hypothesis

Macrolide antibiotics have received criticism concerning their use and risk of treatment failure. Nevertheless, they are an important class of antibiotics and are frequently used in clinical practice for treating a variety of infections. This study sought to utilize pharmacoepidemiology methods and pharmacology principles to estimate the risk of macrolide treatment failure and quantify the influence of their pharmacokinetics on the risk of treatment failure, using clinically reported drug–drug interaction data. Using a large, commercial claims database (2006–2015), inclusion and exclusion criteria were applied to create a cohort of patients who received a macrolide for three common acute infections. Furthermore, an additional analysis examining only bacterial pneumonia events treated with macrolides was conducted. These criteria were formulated specifically to ensure treatment failure would not be expected nor influenced by intrinsic or extrinsic factors. Treatment failure rates were 6% within the common acute infections and 8% in the bacterial pneumonia populations. Regression results indicated that macrolide AUC changes greater than 50% had a significant effect on treatment failure risk, particularly for azithromycin. In fact, our results show that decreased or increased exposure change can influence failure risk, by 35% or 12%, respectively, for the acute infection scenarios. The bacterial pneumonia results were less significant with respect to the regression analyses. This integration of pharmacoepidemiology and clinical pharmacology provides a framework for utilizing real-world data to provide insight into pharmacokinetic mechanisms and support future study development related to antibiotic treatments.

Antibiotic Stewardship und chronische Lungenerkrankungen

Hintergrund

Ziel dieser Arbeit

Material und Methoden

Ergebnisse und Diskussion

A Multicenter Evaluation of the US Prevalence and Regional Variation in Macrolide-Resistant S. pneumoniae in Ambulatory and Hospitalized Adult Patients in the United States

Macrolide resistance was found in 39.5% of 3626 nonduplicate Streptococcus pneumoniae isolates from adult ambulatory and inpatient settings at 329 US hospitals (2018–2019). Macrolide resistance was significantly higher for respiratory vs blood isolates and ambulatory vs inpatient settings. Despite geographic variation, S. pneumoniae macrolide resistance was >25% in most regions.

Impact of Beta-lactam Allergy on Treatment of Outpatient Infections

PURPOSE

The most commonly reported medication allergies in the United States involve beta-lactam antibiotics, creating an important consideration for prescribers when choosing optimal treatment of infections. Currently, few data exist on outpatient prescribing patterns in response to patients with a beta-lactam allergy. This study sought to evaluate the appropriateness of outpatient antibiotic therapy in patients with documented beta-lactam allergies within a Veterans Affairs health care system to evaluate areas of improvement in prescribing practices.

METHODS

Patients receiving outpatient oral antibiotics were prospectively identified through real-time electronic alerts from June 2017 through February 2018. Prescriptions were then reviewed retrospectively to identify appropriateness of antibiotic, drug choice, dose, and duration based on current guideline recommendations. Data were compared between patients with a listed beta-lactam allergy and patients without a beta-lactam allergy to determine the impact on prescribing patterns and outcomes. Baseline characteristics were compared by using descriptive statistics. Significant risk factors for inappropriate prescribing were identified through a multivariable analysis.

FINDINGS

The cohort included 1844 antibiotic prescriptions (documented beta-lactam allergy, 221; no beta-lactam allergy, 1623). Appropriate drug, dose, and duration for antibiotics prescribed in patients reporting a beta-lactam allergy versus nonallergic patients were 44.3% versus 53.0% (P = 0.02), 91.4% versus 86.2% (P = 0.03), and 75.1% versus 76.2% (P = 0.83), respectively. Patients with a reported beta-lactam allergy were 31% less likely to receive the correct drug for indication empirically (95% CI, 0.52-0.92) in the multivariable regression model when adjusted for fluoroquinolone use. In addition, patients reporting a beta-lactam allergy were 2.2 times (95% CI, 1.6-3.0) more likely to receive a fluoroquinolone antibiotic. Antibiotics were considered overall inappropriate based on at least one aspect of therapy in 79.6% of patients reporting a beta-lactam allergy and in 71% of nonallergic patients.

IMPLICATIONS

Antibiotic therapy in patients with a documented beta-lactam allergy was less likely to be appropriate overall, suggesting an area of improvement for prescribing habits. Future interventions should focus on prescriber education regarding first-line and alternative treatments for patients with beta-lactam allergies to ensure that optimal treatment is being provided.

Impact of an Antibiotic Stewardship Program on Antibiotic Prescription for Acute Respiratory Tract Infections in Children: A Prospective Before-After Study

We assessed the effectiveness of an antibiotic stewardship program (ASP) on antibiotic prescriptions for acute respiratory tract infection (ARTI) in a medical school. Our ASP included delivering an antibiotic use guideline via e-mail and LINE (an instant messaging app) to faculty staff, fellows, and residents, and posting of the guideline in examination rooms. Medical records of pediatric patients diagnosed with ARTI were reviewed to assess the appropriateness of antibiotic prescription. ASP could increase the rate of appropriateness from 78% (1979 out of 2553 visits) to 83.4% (2449 out of 2935 visits; P < .001). The baseline of appropriateness was higher in residents (95%) compared with fellows (82%) and faculty staff (75%). The ASP significantly increased the appropriateness only in faculty staff, especially in semiprivate clinics (75% to 83%, P < .001). In conclusion, our ASP increased appropriateness of antibiotic prescriptions for ARTI, with the greatest impact among faculty staff in semiprivate clinics.

International prevalence and risk factors evaluation for drug-resistant Streptococcus pneumoniae pneumonia

OBJECTIVE

Streptococcus pneumoniae is the most frequent bacterial pathogen isolated in subjects with Community-acquired pneumonia (CAP) worldwide. Limited data are available regarding the current global burden and risk factors associated with drug-resistant Streptococcus pneumoniae (DRSP) in CAP subjects. We assessed the multinational prevalence and risk factors for DRSP-CAP in a multinational point-prevalence study.

DESIGN

The prevalence of DRSP-CAP was assessed by identification of DRSP in blood or respiratory samples among adults hospitalized with CAP in 54 countries. Prevalence and risk factors were compared among subjects that had microbiological testing and antibiotic susceptibility data. Multivariate logistic regressions were used to identify risk factors independently associated with DRSP-CAP.

RESULTS

3,193 subjects were included in the study. The global prevalence of DRSP-CAP was 1.3% and continental prevalence rates were 7.0% in Africa, 1.2% in Asia, and 1.0% in South America, Europe, and North America, respectively. Macrolide resistance was most frequently identified in subjects with DRSP-CAP (0.6%) followed by penicillin resistance (0.5%). Subjects in Africa were more likely to have DRSP-CAP (OR: 7.6; 95%CI: 3.34-15.35, p<0.001) when compared to centres representing other continents.

CONCLUSIONS

This multinational point-prevalence study found a low global prevalence of DRSP-CAP that may impact guideline development and antimicrobial policies.

Macrolides induce severe cardiotoxicity and developmental toxicity in zebrafish embryos

Macrolide antibiotics (MALs) are widely used for both human and animal health. Most MALs and their metabolites transfer into aquatic organisms and environment resulting in violent consequences. Previous studies show that MALs cause cardiotoxicity in humans and mammals. However, the potential risk of these chemicals in aquatic organisms remains unclear. Here, we used zebrafish embryos as a model to evaluate the toxicity of MALs. Zebrafish embryos were exposed to four typical MALs including azithromycin (AZM), clarithromycin (CLR), tilmicosin (TMS) and tylosin (TYL) to study their cardiotoxicity. The heart rate of zebrafish embryos showed similar biphasic distribution in the presence of four MALs at 2 days post-fertilization (dpf). The heart rate increased significantly at low levels of MALs while decreased obviously at high levels. Subsequently, TMS was chose to study its acute toxicity and developmental toxicity, which caused pericardial edema and spinal curvature in zebrafish embryos at 4 dpf. Furthermore, we found that TMS triggered oxidative stress, with decreased SOD activities and increased MDA contents. Lastly, apoptosis was observed in zebrafish embryos under TMS treatment, with up-regulation of apoptosis associated genes such as p53, bcl 2, bax, caspase 3 and caspase 9, confirmed by increased protein expression based on Western blot analysis. Taken together, these data indicate that MALs can cause serious toxicity in the development of zebrafish. Great caution should be taken due to the huge consumption of MALs for food animal production and treatments with TMS for infections in aquaculture.

Antimicrobial Stewardship in the Emergency Department

The emergency department (ED) is the hub of the US health care system. Acute infectious diseases are frequently encountered in the ED setting, making this a critical setting for antimicrobial stewardship efforts. Systems level and behavioral stewardship interventions have demonstrated success in the ED setting but successful implementation depends on institutional support and the presence of a physician champion. Antimicrobial stewardship efforts in the ED should target high-impact areas: antibiotic prescribing for nonindicated respiratory tract conditions, such as bronchitis and sinusitis; overtreatment of asymptomatic bacteriuria; and using two antibiotics (double coverage) for uncomplicated cases of cellulitis or abscess.

Molecular Analysis of PBP1A in Streptococcus pneumoniae Isolated from Clinical and Normal Flora Samples in Tehran, Iran: A Multicenter Study

The emergence of high-level penicillin resistance in pneumococcal isolates has seriously complicated the treatment of pneumococcal infections in recent years. The purpose of this study was to determine the serotype, antimicrobial susceptibility, molecular typing, and genetic analysis of the penicillin-binding protein 1a (pbp1a) gene in pneumococcal isolates with high-level resistance to penicillin in Tehran, Iran. PCR amplification, sequencing, and data analysis of the pbp1a gene were carried out for isolates with high-level resistance to penicillin. Antibiotic susceptibility tests showed that the multiple drug resistance pattern "E-CD-OX-TS-T" was the most prevalent (18.0%). The most common serotypes were serotypes 14 (21%), 19F (17%), 23F (16%), and 3 (16%). The highest mutation rates were found in STMK conserved motifs, but no mutation was detected in the other two sequence motifs (SRN and KTG). High-level resistant isolates showed mutations at residues TSQF (574-577) NTGY. Pneumococcal isolates have experienced shifts toward higher penicillin minimal inhibitory concentration levels and other β-lactams. The results of this study show that the presence of multiple substitutions in the pbp1a gene in pneumococcal isolates is highly associated with a reduced affinity to penicillin.

Macrolide-Resistant Mycoplasma pneumoniae Infection, Japan, 2008-2015

We evaluated isolates obtained from children with Mycoplasma pneumoniae infection throughout Japan during 2008–2015. The highest prevalence of macrolide-resistant M. pneumoniae was 81.6% in 2012, followed by 59.3% in 2014 and 43.6% in 2015. The prevalence of macrolide-resistant M. pneumoniae among children in Japan has decreased.

Antimicrobial Resistance Among Streptococcus pneumoniae

Antibiotic resistance in Streptococcus pneumoniae (pneumococcus), the main pathogen responsible for community-acquired pneumonia (CAP), meningitis, bacteremia, and otitis media, is a major concern for clinicians. This pathogen is associated with high rates of morbidity and mortality, especially among children under 2 years old, immunocompromised persons, and the elderly population. The major anti-pneumococcus agents are β-lactams and macrolides, with fluoroquinolones ranking third. The emergence of antibiotic-resistant pneumococcus due to overuse of antibiotics is a global concern. While the discovery of novel classes of antibiotics for the pneumococcus is at a standstill, significant progress in reducing the problem of resistance is associated with antibacterial vaccines. Nevertheless, the World Health Organization recently considered drug-resistant S. pneumoniae as ranking among the 12 bacteria, for which there is an urgent need for new treatments. A challenge is to slow the evolution of new strains that are resistant to the vaccines.

Antimicrobial Resistant Streptococcus pneumoniae: Prevalence, Mechanisms, and Clinical Implications

BACKGROUND

Streptococcus pneumoniae is a major cause of pneumonia, meningitis, sepsis, bacteremia, and otitis media. S. pneumoniae has developed increased resistance to multiple classes of antibiotics.

STUDY DESIGN

Systematic literature review of prevalence, mechanisms, and clinical implications in S. pneumoniae resistance.

AREAS OF UNCERTAINTY

Since S. pneumoniae resistance to penicillin was first reported with subsequent development of resistance to other classes of drugs, selection of appropriate antibiotic treatment is challenging.

DATA SOURCES

We searched PubMed (English language) for citations to antibiotic resistance in S. pneumoniae published before March 1, 2016.

RESULTS

We present a review of S. pneumoniae resistance to beta-lactams, macrolides, lincosamides, fluoroquinolones, tetracyclines, and trimethoprim-sulfamethoxazole (TMP-SMX). There has been a steady decline in susceptibility of S. pneumoniae to commonly used beta-lactams. Phenotypic expression of penicillin resistance occurs as a result of a genetic structural modification in penicillin-binding proteins. Between 20% and 40% of S. pneumoniae isolates are resistant to macrolides. Macrolide resistance mechanisms include ribosomal target site alteration, alteration in antibiotic transport, and modification of the antibiotic. Approximately 22% of S. pneumoniae isolates are resistant to clindamycin. Similar to macrolide resistance, clindamycin involves a target site alteration. The prevalence of fluoroquinolone resistance is low, although increasing. S. pneumoniae resistance to fluoroquinolones occurs by accumulated mutations within the bacterial genome, increased efflux, or acquisition of plasmid-encoded genes. S. pneumoniae resistance has also increased for the tetracyclines. The primary mechanism is mediated by 2 genes that confer ribosomal protection. The prevalence of TMP-SMX resistance is around 35%. As with fluoroquinolones, resistance to TMP-SMX is secondary to mutations in the bacterial genome.

CONCLUSIONS

Effective treatment of resistant S. pneumoniae is a growing concern. New classes of drugs, newer formulations of older drugs, combination antibiotic therapy, nonantibiotic modalities, better oversight of antibiotic usage, and enhanced preventive measures hold promise.

Short-course antimicrobial therapy for paediatric respiratory infections (SAFER): study protocol for a randomized controlled trial

Background

Community-acquired pneumonia (CAP) is commonly diagnosed in children. The Infectious Disease Society of America guidelines recommend 10 days of high-dose amoxicillin for the treatment of non-severe CAP but 5-day “short course” therapy may be just as effective. Randomized trials in adults have already demonstrated non-inferiority of 5-day short-course treatment for adults hospitalized with severe CAP and for adults with mild CAP treated as outpatients. Minimizing exposure to antimicrobials is desirable to avoid harms including diarrhoea, rashes, severe allergic reactions, increased circulating antimicrobial resistance, and microbiome disruption.

Methods

The objective of this multicentre, randomized, non-inferiority, controlled trial is to investigate whether 5 days of high-dose amoxicillin is associated with lower rates of clinical cure 14–21 days later as compared to 10 days of high-dose amoxicillin, the reference standard. Recruitment and enrolment will occur in the emergency departments of McMaster Children’s Hospital and the Children’s Hospital of Eastern Ontario. All children in the study will receive 5 days of amoxicillin after which point they will receive either 5 days of a different formulation of amoxicillin or a placebo. Assuming a clinical failure rate of 5% in the reference arm, a non-inferiority margin of 7.5%, one-sided alpha set at 0.025 and power of 0.80, 270 participants will be required. Participants from a previous feasibility study (n = 60) will be rolled over into the current study. We will be performing multiplex respiratory virus molecular testing, quantification of nasopharyngeal pneumococcal genomic loads, salivary inflammatory marker testing, and faecal microbiome profiling on participants.

Discussion

This is a pragmatic study seeking to provide high-quality evidence for front-line physicians evaluating children presenting with mild CAP in North American emergency departments in the post-13-valent pneumococcal, conjugate vaccine era. High-quality evidence supporting the non-inferiority of short-course therapy for non-severe paediatric CAP should be generated prior to making changes to established guidelines.

Trial registration

ClinicalTrials.gov, NCT02380352. Registered on 2 March 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2457-2) contains supplementary material, which is available to authorized users.

A Simple Approach to Pneumococcal Vaccination in Adults

Streptococcus pneumoniae is a bacterium responsible for a spectrum of diseases including lobar pneumonia, meningitis, otitis media, and sinusitis. Invasive pneumococcal disease is responsible for significant morbidity and mortality across the world. Concerted efforts led to the development of two vaccinations, Pneumova × 23 and Prevnar 13, for the prevention of pneumococcal disease. The Advisory Committee on Immunization Practices of the US Centers for Disease Control and Prevention provides vaccination schedules for predisposed adults, but the proposed schedules remain a challenge to health-care providers. We performed a systematic review in PubMed and these specialty group websites to present the pathophysiology of pneumococcal disease, outline different pneumococcal vaccinations, and condense recommendations for vaccination administration.

In Vivo Pharmacodynamic Evaluation of Omadacycline (PTK 0796) against Streptococcus pneumoniae in the Murine Pneumonia Model

Omadacycline is a novel aminomethylcycline antibiotic in clinical development for community-acquired bacterial pneumonia (CABP). We used a neutropenic murine pneumonia infection model to characterize the in vivo pharmacodynamic activity of omadacycline against Streptococcus pneumoniae Four strains with various phenotypic resistances to other antimicrobials, including tetracyclines, were utilized. Drug concentration measurements were performed in the plasma and epithelial lining fluid (ELF) after administration of 0.5, 2, 8, and 32 mg/kg. Pharmacokinetic parameters were calculated using a noncompartmental model and were linear over the dose range. Penetration into ELF ranged from 72 to 102%. Omadacycline demonstrated net cidal activity in relation to the initial burden against all four strains. The pharmacokinetic/pharmacodynamic index AUC/MIC correlated well with efficacy (R² = 0.74). The plasma 24-h static dose AUC/MIC values were 16 to 20 (24-h ELF AUC/MIC of 14 to 18). A 1-log₁₀ kill was achieved at 24-h plasma AUC/MIC values of 6.1 to 180 (24-h ELF AUC/MIC values 6.0 to 200). A 2-log₁₀ kill was achieved at 24-h plasma AUC/MIC values of 19 to 56 (24-h ELF AUC/MIC of 17 to 47). The targets identified in this study in combination with in vitro potency and favorable human pharmacokinetics make omadacycline an attractive candidate for further development and study in patients with CABP.

Prevalence of pneumococcal serotypes in adults ≥50 years of age

CONTEXT

Currently, majority of studies on antibiotic resistance and serotype prevalence in Streptococcus pneumoniae are in paediatric population and there is limited epidemiologic data pertaining to elderly Indian population.

AIMS

This study was undertaken to assess antibiotic resistance pattern and the coverage of the polysaccharide vaccine 23 (PPV23) in the elderly population.

SETTINGS AND DESIGN

This was a prospective 2-year pneumococcal surveillance study in patients with community-acquired pneumococcal infections of ≥50 years' age group on fifty isolates of S. pneumoniae.

MATERIALS AND METHODS

Antibiotic susceptibility by Kirby-Bauer disc diffusion method and minimum inhibitory concentration susceptibility testing by E-test method were performed for various antibiotics. All isolates were serotyped by the capsular Quellung method with commercial antisera.

RESULTS

All S. pneumoniae isolates were sensitive to penicillin and ceftriaxone. Non-susceptibility to levofloxacin, co-trimoxazole, erythromycin and clindamycin was noted as 16%, 74%, 10% and 6%, respectively. Prevalence of multidrug resistance in S. pneumoniae was observed as 6%. The most common serotypes observed in our study were 19A (14%), 8 (10%), 19F (8%), 3 (6%) and 9N (6%). PCV7, PCV10, PCV13 and PCV23 coverage was observed as 16%, 24%, 48% and 66%, respectively. The non-vaccine serotypes (NVTs) comprised 30% (n = 15) of the isolates.

CONCLUSIONS

Our study shows different antibiotic susceptibility patterns of S. pneumoniae as compared to other neighbouring regions in Asia. The modest coverage of S. pneumoniae serotypes by PPV23 vaccine and prevalence of diverse NVTs in adult population make it a challenging task to recommend further changes in the future vaccine.

Risk Factors for Outpatient Use of Antibiotics in Children with Acute Respiratory Illnesses

OBJECTIVES

Antibiotics for acute respiratory illness (ARI) constitute most pediatric medication use and contribute to the emergence of antimicrobial resistance. We investigated antibiotic prescription risk factors for ARI in pediatric clinics and clinical follow-up in individuals prescribed and not prescribed antibiotics.

METHODS

In this observational study, we enrolled children ages 2 to 17 years old presenting with ARI with fever to two academic pediatric primary care outpatient clinics during influenza season 2013-2014. We collected information on demographics, initial symptoms, medical conditions, laboratory tests, discharge diagnoses, treatments, and 30 days of follow-up medical encounters. Factors associated with antibiotic prescription receipt were evaluated using logistic regression.

RESULTS

Of 206 consented and enrolled children, 59 (29%) were prescribed antibiotics, 51 of 59 (86%) for indicated diagnoses: 34 for streptococcal pharyngitis, 15 for acute otitis media (AOM), and 2 for pneumonia. Discharge diagnoses were the only factors independently associated with an antibiotic prescription. Of children prescribed/not prescribed an antibiotic, 17%/17% received follow-up telephone calls and 27%/17% had follow-up visits related to ARI within 30 days. Two children with AOM were prescribed a second antibiotic during follow-up, and one developed Clostridium difficile colitis. Eighteen of 206 (9%) additional children were prescribed antibiotics within 30 days for ARI symptoms, 17 for streptococcal pharyngitis, AOM, pneumonia, or sinusitis; one was prescribed antibiotics for influenza-like illness.

CONCLUSIONS

Among study children 2 to 17 years old with outpatient ARI, 29% were prescribed antibiotics at the initial visit and another 9% were prescribed antibiotics during the 30-day follow-up (most were for appropriate indications). Further decreasing antibiotic use in similar settings will likely require wider implementation of watchful waiting for AOM, a change in guidelines for pharyngitis management, and/or reductions in these diseases.

Resistance to Macrolide Antibiotics in Public Health Pathogens

Macrolide resistance mechanisms can be target-based with a change in a 23S ribosomal RNA (rRNA) residue or a mutation in ribosomal protein L4 or L22 affecting the ribosome's interaction with the antibiotic. Alternatively, mono- or dimethylation of A2058 in domain V of the 23S rRNA by an acquired rRNA methyltransferase, the product of an erm (erythromycin ribosome methylation) gene, can interfere with antibiotic binding. Acquired genes encoding efflux pumps, most predominantly mef(A) + msr(D) in pneumococci/streptococci and msr(A/B) in staphylococci, also mediate resistance. Drug-inactivating mechanisms include phosphorylation of the 2'-hydroxyl of the amino sugar found at position C5 by phosphotransferases and hydrolysis of the macrocyclic lactone by esterases. These acquired genes are regulated by either translation or transcription attenuation, largely because cells are less fit when these genes, especially the rRNA methyltransferases, are highly induced or constitutively expressed. The induction of gene expression is cleverly tied to the mechanism of action of macrolides, relying on antibiotic-bound ribosomes stalled at specific sequences of nascent polypeptides to promote transcription or translation of downstream sequences.

Emerging non-PCV13 serotypes of noninvasive Streptococcus pneumoniae with macrolide resistance genes in northern Japan

In Japan, the 7-valent pneumococcal conjugate vaccine (PCV7) was introduced to the nation's routine immunization program in April 2013 and was replaced by the 13-valent pneumococcal conjugate vaccine (PCV13) in November 2013. Distribution of serotypes and macrolide resistance genotypes was investigated for a total of 1097 (975 children, 122 adults) and 960 (873 children, 87 adults) clinical isolates of Streptococcus pneumoniae from noninvasive infections in Hokkaido (northern main island of Japan) in the routine immunization periods for PCV7 and PCV13 (April–October 2013 and November 2013–November 2014, respectively). Serotype was determined by sequential multiplex PCR and additional genetic analyses. Macrolide resistance genes erm(B) and mef(A/E) were detected by multiplex PCR. Although the most prevalent serotypes in children were 23A and 6C in the PCV7 period, after replacement with PCV13, 19A became the most common, followed by 6C, 15A and 23A. Among adults, serotype 3 was consistently the most frequent throughout the study periods. Compared with values from the pre-PCV7 routine immunization period, PCV7 serotypes decreased from 48.3 to 3.3% in the PCV13 period among children, while the rates of non-PCV13 serotypes (particularly 15A, 23A, 11A, 10A and 35B) increased from 39.7 to 75.1% (p < 0.001). In the PCV13 period, erm(B), mef(A/E) and both of these genes were detected in 75.8, 31.6 and 11.3% of all isolates, respectively. Serotype 19A accounted for 76.9% of the isolates with both the macrolide resistance genes, and emerging non-PCV13 serotypes 15A, 15C and 23A mostly harboured erm(B).

Polymicrobial community-acquired pneumonia: An emerging entity

Polymicrobial aetiology in community-acquired pneumonia (CAP) is more common than previously recognized. This growing new entity can influence inflammation, host immunity and disease outcomes in CAP patients. However, the true incidence is complicated to determine and probably underestimated due mainly to many cases going undetected, particularly in the outpatient setting, as the diagnostic yield is restricted by the sensitivity of currently available microbiologic tests and the ability to get certain types of clinical specimens. The observed rate of polymicrobial cases may also lead to new antibiotic therapy considerations. In this review, we discuss the pathogenesis, microbial interactions in pneumonia, epidemiology, biomarkers and antibiotic therapy for polymicrobial CAP.

Variation in Outpatient Antibiotic Prescribing for Acute Respiratory Infections in the Veteran Population: A Cross-sectional Study

BACKGROUND

Despite efforts to reduce antibiotic prescribing for acute respiratory infections (ARIs), information on factors that drive prescribing is limited.

OBJECTIVE

To examine trends in antibiotic prescribing in the Veterans Affairs population over an 8-year period and to identify patient, provider, and setting sources of variation.

DESIGN

Retrospective, cross-sectional study.

SETTING

All emergency departments and primary and urgent care clinics in the Veterans Affairs health system.

PARTICIPANTS

All patient visits between 2005 and 2012 with primary diagnoses of ARIs that typically had low proportions of bacterial infection. Patients with infections or comorbid conditions that indicated antibiotic use were excluded.

MEASUREMENTS

Overall antibiotic prescription; macrolide prescription; and patient, provider, and setting characteristics extracted from the electronic health record.

RESULTS

The proportion of 1 million visits with ARI diagnoses that resulted in antibiotic prescriptions increased from 67.5% in 2005 to 69.2% in 2012 (P < 0.001). The proportion of macrolide antibiotics prescribed increased from 36.8% to 47.0% (P < 0.001). Antibiotic prescribing was highest for sinusitis (adjusted proportion, 86%) and bronchitis (85%) and varied little according to fever, age, setting, or comorbid conditions. Substantial variation was identified in prescribing at the provider level: The 10% of providers who prescribed the most antibiotics did so during at least 95% of their ARI visits, and the 10% who prescribed the least did so during 40% or fewer of their ARI visits.

LIMITATION

Some clinical data that may have influenced the prescribing decision were missing.

CONCLUSION

Veterans with ARIs commonly receive antibiotics, regardless of patient, provider, or setting characteristics. Macrolide use has increased, and substantial variation was identified in antibiotic prescribing at the provider level.

PRIMARY FUNDING SOURCE

U.S. Department of Veterans Affairs, Centers for Disease Control and Prevention.

Advances in pneumococcal antibiotic resistance

Antimicrobial resistance and serotypes in Streptococcus pneumoniae have been evolving with the widespread use of antibiotics and the introduction of pneumococcal conjugate vaccines (PCV). Particularly, among various types of antimicrobial resistance, macrolide resistance has most remarkably increased in many parts of the world, which has been reported to be >70% among clinical isolates from Asian countries. Penicillin resistance has dramatically decreased among nonmeningeal isolates due to the changes in resistance breakpoints, although resistance to other β-lactams such as cefuroxime has increased. Multidrug resistance became a serious concern in the treatment of invasive pneumococcal diseases, especially in Asian countries. After PCV7 vaccination, serotype 19A has emerged as an important cause of invasive pneumococcal diseases which was also associated with increasing prevalence of multidrug resistance in pneumococci. Widespread use of PCV13, which covers additional serotypes 3, 6A and 19A, may contribute to reduce the clonal spread of drug-resistant 19A pneumococci.

Mobile elements and chromosomal changes associated with MLS resistance phenotypes of invasive pneumococci recovered in the United States

Pneumococcal macrolide resistance is usually expressed as one of two phenotypes: the M phenotype conferred by the mef gene or the MLSB phenotype caused by modification of ribosomal targets, most commonly mediated by an erm methylase. Target-site modification leading to antibiotic resistance can also occur due to sequence mutations within the 23S rRNA or the L4 and L22 riboproteins. We screened 4,535 invasive isolates resistant to erythromycin and 18 invasive isolates nonsusceptible to quinupristin-dalfopristin (Q-D) to deduce the potential mechanisms involved. Of 4,535 erythromycin-resistant isolates, 66.2% were polymerase chain reaction (PCR)-positive for mef alone, 17.8% for ermB alone, and 15.1% for both mef and ermB. Thirty-seven isolates (0.9%) were PCR negative for both determinants. Of these, 3 were positive for ermA (subclass ermTR) and 25 had chromosomal mutations. No chromosomal mutations (in 23S rRNA, rplD, or rplV) nor any of the macrolides/lincosamides/streptogramin (MLS) resistance genes screened for (ermT, ermA, cfr, lsaC, and vgaA) were found in the remaining nine isolates. Of 18 Q-D nonsusceptible isolates, 14 had chromosomal mutations and one carried both mef and ermB; no chromosomal mutations or other resistance genes were found in 3 isolates. Overall, we found 28 mutations, 13 of which have not been previously described in Streptococcus pneumoniae. The role of these mutations remains to be confirmed by transformation assays.

Gradenigo syndrome: unusual consequence of otitis media

INTRODUCTION

In 1904, Giuseppe Gradenigo published his case series on the triad of ipsilateral abducens nerve palsy, facial pain in the trigeminal nerve distribution, and suppurative otitis media, which would subsequently be referred to as Gradenigo syndrome.

CASE REPORT

Our patient was a 36-year-old female, 23 weeks pregnant, with a 6-day history of right-sided otalgia and hearing loss and a 4-day history of purulent otorrhea, who presented with severe, holocephalic headache, meningeal signs, fever, photophobia, and mental status decline. Lumbar puncture yielded a white blood cell count of 1,559 cells/mm(3) with 95% polymorphonuclear leukocytes, a red blood cell count of 111 cells/mm(3), a protein level of 61 mg/dl, and a glucose level of <40 mg/dl. Cerebrospinal fluid Gram stain showed Gram-positive diplococci, which were subsequently identified as Streptococcus pneumoniae and treated with ceftriaxone. On the second hospital day, she developed horizontal diplopia due to right abducens nerve palsy and right mydriasis. Both symptoms resolved on the third hospital day. Erosion of temporal bone and opacification of mastoid air cells was shown on CT scan. A CT venogram showed an irregularity of the left transverse and superior sagittal sinuses. She was treated with enoxaparin for possible sinus thrombosis.

DISCUSSION

This case demonstrates rare but serious sequelae of otitis media and Gradenigo syndrome. Holocephalic headache from meningitis masked trigeminal pain. Involvement of the ipsilateral petrous apex and surrounding structures on imaging and clinical improvement with antibiotic treatment supports Gradenigo syndrome over intracranial hypertension due to venous sinus thrombosis as the cause of the abducens nerve palsy.

High burden of antimicrobial drug resistance in Asia

The rapid development of antimicrobial resistance among micro-organisms is a serious public health concern. Moreover, the dissemination of antibiotic-resistant bacteria makes this issue a global problem, and Asia is no exception. For example, since New Delhi metallo-β-lactamase (NDM)-producing Enterobacteriaceae were identified in India, further spread of NDM has become a worldwide threat. However, the epidemiology of antibiotic-resistant bacteria in Asia may be different to other regions, and clinical condition may be worse than in western countries. Antibiotic-resistant bacteria, including community-acquired and hospital-acquired meticillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA), vancomycin-resistant enterococci, macrolide- and penicillin-resistant Streptococcus pneumoniae, extend-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, carbapenem-resistant Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa and Acinetobacter spp., are becoming prevalent in many countries in Asia. Moreover, the prevalence of each antibiotic-resistant bacterium in each country is not identical. This review provides useful information regarding the critical condition of antibiotic resistance in Asia and emphasises the importance of continuous surveillance of resistance data.

Streptococcus pneumoniae non-susceptibility and outpatient antimicrobial prescribing rates at the Alaska Native Medical Center

Background

American Indian/Alaska Native (AI/AN) people suffer substantially higher rates of invasive pneumococcal disease (IPD) than the general US population. We evaluated antimicrobial prescribing data and their association with non-susceptibility in Streptococcus pneumoniae causing IPD in AI/AN people between 1992 and 2009.

Methods

Antimicrobial use data were gathered from the electronic patient management system and included all prescriptions dispensed to Alaska Native patients aged 5 years and older from outpatient pharmacies at the Alaska Native Medical Center (ANMC). Antimicrobial susceptibility data were gathered from pneumococcal isolates causing IPD among Anchorage Service Unit AI/AN residents aged 5 years and older. Data were restricted to serotypes not contained in the pneumococcal vaccine (PCV7).

Results

Over the study period, overall antimicrobial prescribing increased 59% (285/1,000 persons/year in 1992 to 454/1,000 persons per year in 2009, p<0.001). Trimethoprim/sulfamethoxazole prescribing increased (43/1,000 persons/year in 1992 to 108/1,000 persons/year in 2009, p<0.001) and non-susceptibility to trimethoprim/sulfamethoxazole in AI/AN patients ≥5 years of age increased in non-PCV7 serotypes (0–12%, p<0.05). Similarly, prescribing rates increased for macrolide antibiotics (46/1,000 persons/year in 1992 to 84/1,000 persons/year in 2009, p<0.05). We observed no statistically significant change over time in erythromycin non-susceptibility among non-PCV7 serotypes in AI/AN patients aged 5 years or greater (0–7%, p=0.087).

Conclusion

Antimicrobial prescribing patterns of some antibiotics in the AI/AN population corresponded to increased antimicrobial resistance in clinical isolates. This study highlights the on-going threat of antimicrobial resistance, the critical importance of judicious prescribing of antibiotics and the potential utility of prescribing data for addressing this issue.

Antibiotic activity against naive and induced Streptococcus pneumoniae biofilms in an in vitro pharmacodynamic model

Biofilms play a role in the pathogenicity of pneumococcal infections. A pharmacodynamic in vitro model of biofilm was developed that allows characterization of the activity of antibiotics against viability and biomass by using in parallel capsulated (ATCC 49619) and noncapsulated (R6) reference strains. Naive biofilms were obtained by incubating fresh planktonic cultures for 2 to 11 days in 96-well polystyrene plates. Induced biofilms were obtained using planktonic bacteria collected from the supernatant of 6-day-old naive biofilms. Biomass production was more rapid and intense in the induced model, but the levels were similar for both strains. Full concentration responses fitting sigmoidal regressions allowed calculation of maximal efficacies and relative potencies of drugs. All antibiotics tested (amoxicillin, clarithromycin, solithromycin, levofloxacin, and moxifloxacin) were more effective against young naive biofilms than against old or induced biofilms, except macrolides/ketolides, which were as effective at reducing viability in 2-day-old naive biofilms and in 11-day-old induced biofilms of R6. Macrolides/ketolides, however, were less potent than fluoroquinolones against R6 (approximately 5- to 20-fold-higher concentrations needed to reduction viability of 20%). However, at concentrations obtainable in epithelial lining fluid, the viabilities of mature or induced biofilms were reduced 15 to 45% (amoxicillin), 17 to 44% (macrolides/ketolides), and 12 to 64% (fluoroquinolones), and biomasses were reduced 5 to 45% (amoxicillin), 5 to 60% (macrolides/ketolides), and 10 to 76% (fluoroquinolones), with solithromycin and moxifloxacin being the most effective and the most potent agents (due to lower MICs) in their respective classes. This study allowed the ranking of antibiotics with respect to their potential effectiveness in biofilm-related infections, underlining the need to search for still more effective options.

Genotypic characterization of Streptococcus pneumoniae serotype 19F in Malaysia

Streptococcus pneumoniae is an epidemiologically important bacterial pathogen. Recently, we reported the antibiotic susceptibility patterns of a limited collection of pneumococcal isolates in Malaysia with a high prevalence of erythromycin resistant strains. In the present study, 55 of the pneumococcal isolates of serotype 19F were further analysed by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). The generated genotypic patterns were then correlated with the antibiograms previously reported. Forty-seven different PFGE profiles (PTs) were obtained, showing that the isolates were genetically diverse. MLST identified 16 sequence types (STs) with ST-236 being predominant (58.2%), followed by ST-81 (10.3%). Among the ST-236 isolates, 22 were erythromycin resistant S. pneumoniae (ERSP) and 15 were trimethoprim/sulfamethoxazole (TMP/SMX) resistant, while among ST-81, four isolates were ERSP and two were TMP/SMX resistant. The high prevalence of erythromycin resistant serotype 19F isolates of ST-236 in this study has also been reported in other North and South East Asian countries.

Principles of judicious antibiotic prescribing for upper respiratory tract infections in pediatrics

Most upper respiratory tract infections are caused by viruses and require no antibiotics. This clinical report focuses on antibiotic prescribing strategies for bacterial upper respiratory tract infections, including acute otitis media, acute bacterial sinusitis, and streptococcal pharyngitis. The principles for judicious antibiotic prescribing that are outlined focus on applying stringent diagnostic criteria, weighing the benefits and harms of antibiotic therapy, and understanding situations when antibiotics may not be indicated. The principles can be used to amplify messages from recent clinical guidelines for local guideline development and for patient communication; they are broadly applicable to antibiotic prescribing in general.

Molecular resistance mechanisms of macrolide-resistant invasive Streptococcus pneumoniae isolates from Alaska, 1986 to 2010

The rapid emergence of antibiotic-resistant pneumococcal strains has reduced treatment options. The aim of this study was to determine antimicrobial susceptibilities, serotype distributions, and molecular resistance mechanisms among macrolide-resistant invasive pneumococcal isolates in Alaska from 1986 to 2010. We identified cases of invasive pneumococcal disease in Alaska from 1986 to 2010 through statewide population-based laboratory surveillance. All invasive pneumococcal isolates submitted to the Arctic Investigations Program laboratory were confirmed by standard microbiological methods and serotyped by slide agglutination and the Quellung reaction. MICs were determined by the broth microdilution method, and macrolide-resistant genotypes were determined by multiplex PCR. Among 2,923 invasive pneumococcal isolates recovered from 1986 to 2010, 270 (9.2%) were nonsusceptible to erythromycin; 177 (66%) erythromycin-nonsusceptible isolates demonstrated coresistance to penicillin, and 167 (62%) were multidrug resistant. The most frequent serotypes among the macrolide-resistant isolates were serotypes 6B (23.3%), 14 (20.7%), 19A (16.7%), 9V (8.9%), 19F (6.3%), 6A (5.6%), and 23F (4.8%). mef and erm(B) genes were detected in 207 (77%) and 32 (12%) of the isolates, respectively. Nineteen (7%) of the erythromycin-nonsusceptible isolates contained both mef and erm(B) genotypes; 15 were of serotype 19A. There was significant year-to-year variation in the proportion of isolates that were nonsusceptible to erythromycin (P < 0.001). Macrolide resistance among pneumococcal isolates from Alaska is mediated predominantly by mef genes, and this has not changed significantly over time. However, there was a statistically significant increase in the proportion of isolates that possess both erm(B) and mef, primarily due to serotype 19A isolates.

Risks of population antimicrobial resistance associated with chronic macrolide use for inflammatory airway diseases

Macrolide antibiotics have established efficacy in the management of cystic fibrosis and diffuse panbronchiolitis-uncommon lung diseases with substantial morbidity and the potential for rapid progression to death. Emerging evidence suggests benefits of maintenance macrolide treatment in more indolent respiratory diseases including chronic obstructive pulmonary disease and non-cystic fibrosis bronchiectasis. In view of the greater patient population affected by these disorders (and potential for macrolide use to spread to disorders such as chronic cough), widespread use of macrolides, particularly azithromycin, has the potential to substantially influence antimicrobial resistance rates of a range of respiratory microbes. In this Personal View, I explore theories around population (rather than patient) macrolide resistance, appraise evidence linking macrolide use with development of resistance, and highlight the risks posed by injudicious broadening of their use, particularly of azithromycin. These risks are weighed against the potential benefits of macrolides in less aggressive inflammatory airway disorders. A far-sighted approach to maintenance macrolide use in non-cystic fibrosis inflammatory airway diseases is needed, which minimises risks of adversely affecting community macrolide resistance: combining preferential use of erythromycin and restriction of macrolide use to those patients at greatest risk represents an appropriately cautious management approach.

Functionally cloned pdrM from Streptococcus pneumoniae encodes a Na(+) coupled multidrug efflux pump

Multidrug efflux pumps play an important role as a self-defense system in bacteria. Bacterial multidrug efflux pumps are classified into five families based on structure and coupling energy: resistance−nodulation−cell division (RND), small multidrug resistance (SMR), major facilitator (MF), ATP binding cassette (ABC), and multidrug and toxic compounds extrusion (MATE). We cloned a gene encoding a MATE-type multidrug efflux pump from Streptococcus pneumoniae R6, and designated it pdrM. PdrM showed sequence similarity with NorM from Vibrio parahaemolyticus, YdhE from Escherichia coli, and other bacterial MATE-type multidrug efflux pumps. Heterologous expression of PdrM let to elevated resistance to several antibacterial agents, norfloxacin, acriflavine, and 4′,6-diamidino-2-phenylindole (DAPI) in E. coli KAM32 cells. PdrM effluxes acriflavine and DAPI in a Na⁺- or Li⁺-dependent manner. Moreover, Na⁺ efflux via PdrM was observed when acriflavine was added to Na⁺-loaded cells expressing pdrM. Therefore, we conclude that PdrM is a Na⁺/drug antiporter in S. pneumoniae. In addition to pdrM, we found another two genes, spr1756 and spr1877,that met the criteria of MATE-type by searching the S. pneumoniae genome database. However, cloned spr1756 and spr1877 did not elevate the MIC of any of the investigated drugs. mRNA expression of spr1756, spr1877, and pdrM was detected in S. pneumoniae R6 under laboratory growth conditions. Therefore, spr1756 and spr1877 are supposed to play physiological roles in this growth condition, but they may be unrelated to drug resistance.

Novel 3-O-carbamoyl erythromycin A derivatives (carbamolides) with activity against resistant staphylococcal and streptococcal isolates

A novel series of 3-O-carbamoyl erythromycin A derived analogs, labeled carbamolides, with activity versus resistant bacterial isolates of staphylococci (including macrolide and oxazolidinone resistant strains) and streptococci are reported. An (R)-2-aryl substituent on a pyrrolidine carbamate appeared to be critical for achieving potency against resistant strains. Crystal structures showed a distinct aromatic interaction between the (R)-2-aryl (3-pyridyl for 4d) substituent on the pyrrolidine and G2484 (G2505, Escherichia coli) of the Deinococcus radiodurans 50S ribosome (3.2Å resolution).

Macrolide resistance determinants among Streptococcus pneumoniae isolates from carriers in Central Greece

Background

We sought to characterize the temporal trends in nasopharyngeal carriage of macrolide-resistant pneumococci during a period with increased heptavalent pneumococcal conjugate vaccine (PCV7) coverage in Central Greece.

Methods

Streptococcus pneumoniae isolates were recovered from 2649 nasopharyngeal samples obtained from day-care center attendees in Central Greece during 2005–2009. A phenotypic and genotypic analysis of the isolates was performed, including the identification of macrolide resistance genes mef(A), subclasses mef(A) and mef(E), as well as erm(B).

Results

Of the 1105 typeable S. pneumoniae isolates, 265 (24%) were macrolide-resistant; 22% in 2005, 33.3% in 2006, 23.7% in 2007, and 20.5% in 2009 (P=0.398). Among these macrolide-resistant pneumococci, 28.5% possessed erm(B), 24.3% erm(B)+mef(E), 41.8% mef(E), and 5.3% mef(A). A mef gene as the sole resistance determinant was carried by 31% of macrolide-resistant isolates belonging to PCV7 serotypes and 75.8% of the non-PCV7 serotypes. Across the 4 annual surveillances, pneumococci carrying mef(A) gradually disappeared, whereas serotype 19F isolates carrying both erm(B) and mef(E) persisted without significant yearly fluctuations. Among isolates belonging to non-PCV7 serotypes, macrolide-resistance was observed in those of serotypes 6A, 19A, 10A, 15A, 15B/C, 35F, 35A, and 24F. In 2009, ie 5 years after the introduction of PCV7 in our country, 59% of macrolide-resistant pneumococci belonged to non-PCV7 serotypes.

Conclusions

Across the study period, the annual frequency of macrolide-resistant isolates did not change significantly, but in 2009 a marked shift to non-PCV7 serotypes occurred. Overall, more than half of the macrolide-resistant isolates possessed erm(B) either alone or in combination with mef(E). erm(B) dominated among isolates belonging to PCV7 serotypes, but not among those of non-PCV7 serotypes.

IDSA Clinical Practice Guideline for Acute Bacterial Rhinosinusitis in Children and Adults

Evidence-based guidelines for the diagnosis and initial management of suspected acute bacterial rhinosinusitis in adults and children were prepared by a multidisciplinary expert panel of the Infectious Diseases Society of America comprising clinicians and investigators representing internal medicine, pediatrics, emergency medicine, otolaryngology, public health, epidemiology, and adult and pediatric infectious disease specialties. Recommendations for diagnosis, laboratory investigation, and empiric antimicrobial and adjunctive therapy were developed.

Current concepts in laboratory testing to guide antimicrobial therapy

Antimicrobial susceptibility testing (AST) is indicated for pathogens contributing to an infectious process that warrants antimicrobial therapy if susceptibility to antimicrobials cannot be predicted reliably based on knowledge of their identity. Such tests are most frequently used when the etiologic agents are members of species capable of demonstrating resistance to commonly prescribed antibiotics. Some organisms have predictable susceptibility to antimicrobial agents (ie, Streptococcus pyogenes to penicillin), and empirical therapy for these organisms is typically used. Therefore, AST for such pathogens is seldom required or performed. In addition, AST is valuable in evaluating the activity of new and experimental compounds and investigating the epidemiology of antimicrobial resistant pathogens. Several laboratory methods are available to characterize the in vitro susceptibility of bacteria to antimicrobial agents. When the nature of the infection is unclear and the culture yields mixed growth or usual microbiota (wherein the isolates usually bear little relationship to the actual infectious process), AST is usually unnecessary and results may, in fact, be dangerously misleading. Phenotypic methods for detection of specific antimicrobial resistance mechanisms are increasingly being used to complement AST (ie, inducible clindamycin resistance among several gram-positive bacteria) and to provide clinicians with preliminary direction for antibiotic selection pending results generated from standardized AST (ie, β-lactamase tests). In addition, molecular methods are being developed and incorporated by microbiology laboratories into resistance detection algorithms for rapid, sensitive assessment of carriage states of epidemiologically and clinically important pathogens, often directly from clinical specimens (ie, presence of vancomycin-resistant enterococci in fecal specimens).

Doxycycline vs. macrolides in combination therapy for treatment of community-acquired pneumonia

We assessed the comparative efficacy of empirical therapy with beta-lactam plus macrolide vs. beta-lactam plus doxycycline for the treatment of community-acquired pneumonia (CAP) among patients in the Australian Community-Acquired Pneumonia Study. Both regimens demonstrated similar outcomes against CAP due to either 'atypical' (Chlamydophila, Legionella or Mycoplasma spp.) or typical bacterial pathogens.

Changing trends in antimicrobial resistance and serotypes of Streptococcus pneumoniae isolates in Asian countries: an Asian Network for Surveillance of Resistant Pathogens (ANSORP) study

Antimicrobial resistance in Streptococcus pneumoniae remains a serious concern worldwide, particularly in Asian countries, despite the introduction of heptavalent pneumococcal conjugate vaccine (PCV7). The Asian Network for Surveillance of Resistant Pathogens (ANSORP) performed a prospective surveillance study of 2,184 S. pneumoniae isolates collected from patients with pneumococcal infections from 60 hospitals in 11 Asian countries from 2008 to 2009. Among nonmeningeal isolates, the prevalence rate of penicillin-nonsusceptible pneumococci (MIC, ≥ 4 μg/ml) was 4.6% and penicillin resistance (MIC, ≥ 8 μg/ml) was extremely rare (0.7%). Resistance to erythromycin was very prevalent in the region (72.7%); the highest rates were in China (96.4%), Taiwan (84.9%), and Vietnam (80.7%). Multidrug resistance (MDR) was observed in 59.3% of isolates from Asian countries. Major serotypes were 19F (23.5%), 23F (10.0%), 19A (8.2%), 14 (7.3%), and 6B (7.3%). Overall, 52.5% of isolates showed PCV7 serotypes, ranging from 16.1% in Philippines to 75.1% in Vietnam. Serotypes 19A (8.2%), 3 (6.2%), and 6A (4.2%) were the most prominent non-PCV7 serotypes in the Asian region. Among isolates with serotype 19A, 86.0% and 79.8% showed erythromycin resistance and MDR, respectively. The most remarkable findings about the epidemiology of S. pneumoniae in Asian countries after the introduction of PCV7 were the high prevalence of macrolide resistance and MDR and distinctive increases in serotype 19A.