Antimicrobial Treatment Guidelines for Acute Bacterial Rhinosinusitis

Rational Prophylactic Antibiotic Selection for Sinus Elevation Surgery

FOCUSED CLINICAL QUESTION

For a generally healthy patient with no risk indicators for postoperative infection, what is the most appropriate perioperative antibiotic regimen for sinus elevation surgery in terms of reducing postoperative infection risk and minimizing untoward effects?

CLINICAL SCENARIO

A 38-year-old female patient in good general and periodontal health presents missing tooth #14 (Fig. ). She reports no systemic conditions, no history of sinusitis, and no allergies. Medications include acetaminophen and ibuprofen as needed for pain. The patient's dentition is minimally restored, with no active caries. Cone-beam computed tomography reveals a clear, pneumatized left maxillary sinus and inadequate bone volume to support dental implant placement (Fig. ). No septa or pathologic lesions are present, the ostium appears patent, and no thickening of the Schneiderian membrane is appreciable. The patient states that she wants to replace her missing molar without restoring adjacent teeth (Figs. and ). [Figure: see text] [Figure: see text] [Figure: see text] [Figure: see text].

High Prevalence of Antibiotic Resistance in Isolates from the Middle Meatus of Children and Adults with Acute Rhinosinusitis

Background

The pathogens in acute rhinosinusitis are similar worldwide. An increase in antibiotic resistance has been shown in a large number of studies in recent years. The prevalence of resistance varies greatly in different countries. This study was performed to determine the endemic prevalence of antibiotic resistance in pathogens of acute rhinosinusitis in Taiwan.

Methods

Middle meatus discharge was taken for aerobic culture in 133 outpatients with the diagnosis of acute rhinosinusitis.

Results

One hundred two isolates of pathogens were found, including three major bacteria: Haemophilus influenzae (37.3%), Streptococcus pneumoniae (28.4%), and Moraxella catarrhalis (11.8%). Polymicrobial infections and positive cultures occurred more frequently in pediatric patients, as did recovery of M. catarrhalis infection. An extremely high percentage of resistance to first-line antibiotics was noted, viz., penicillin-nonsusceptible S. pneumoniae (PNSSP) (72.4%), ampicillin-resistant H. influenzae (60.5%), and M. catarrhalis (58.3%).

Conclusion

The high prevalence of drug resistance is a great threat to public health. Antibiotic use should be more prudent, especially in pediatric patients, who were found to be more susceptible to bacterial rhinosinusitis and multiple pathogenic infection.

Community-Based Treatment of Acute Uncomplicated Bacterial Rhinosinusitis with Gatifloxacin

OBJECTIVE: We sought to evaluate gatifloxacin in adults with acute uncomplicated bacterial rhinosinusitis.

STUDY DESIGN: TeqCES was an open-label, multicenter, noncomparative study of the safety and efficacy of gatifloxacin. More than 11,000 adult patients with acute uncomplicated rhinosinusitis received gatifloxacin 400 mg once daily for 10 days.

RESULTS: Moraxella catarrhalis (91% β-lactamase producers), Haemophilus influenzae (28% β-lactamase producers), Streptococcus pneumoniae (18% intermediately resistant and 14% fully resistant to penicillin), and Staphylococcus aureus were the predominant pathogens isolated from purulent nasal discharge. More than 99% of rhinosinusitis pathogens isolated from the nasopharynx of patients meeting the clinical criteria for rhinosinusitis were susceptible to gatifloxacin. Among 10,353 patients whose clinical response could be determined, 91.6% were cured. Clinical cure rates exceeded 90% for the major pathogens. Gatifloxacin was well tolerated; drug-related adverse events that occurred in 1% or more of patients were nausea (4.4%), dizziness (1.8%), diarrhea (1.4%), and headache (1.0%).

CONCLUSION: Gatifloxacin is effective for patients with acute bacterial rhinosinusitis in the community.!

Acute sinusitis

Clinical diagnosis of acute sinusitis is troublesome because it involves use of a cluster of diagnostic criteria that have only moderate sensitivity. Ancillary testing with radiography or antral puncture is impractical, expensive, and usually unnecessary in the primary care setting. Antibiotic therapy is not beneficial for most patients in whom acute sinusitis is suspected, even when radiographic abnormalities are found. Simple management algorithms and patient information are now available to aid primary care physicians in offering appropriate therapeutic measures and reassuring patients who are expecting "'a pill for every ill' when that pill is an antibacterial."

Beta- lactam antibiotics stimulate biofilm formation in non-typeable haemophilus influenzae by up-regulating carbohydrate metabolism

Non-typeable Haemophilus influenzae (NTHi) is a common acute otitis media pathogen, with an incidence that is increased by previous antibiotic treatment. NTHi is also an emerging causative agent of other chronic infections in humans, some linked to morbidity, and all of which impose substantial treatment costs. In this study we explore the possibility that antibiotic exposure may stimulate biofilm formation by NTHi bacteria. We discovered that sub-inhibitory concentrations of beta-lactam antibiotic (i.e., amounts that partially inhibit bacterial growth) stimulated the biofilm-forming ability of NTHi strains, an effect that was strain and antibiotic dependent. When exposed to sub-inhibitory concentrations of beta-lactam antibiotics NTHi strains produced tightly packed biofilms with decreased numbers of culturable bacteria but increased biomass. The ratio of protein per unit weight of biofilm decreased as a result of antibiotic exposure. Antibiotic-stimulated biofilms had altered ultrastructure, and genes involved in glycogen production and transporter function were up regulated in response to antibiotic exposure. Down-regulated genes were linked to multiple metabolic processes but not those involved in stress response. Antibiotic-stimulated biofilm bacteria were more resistant to a lethal dose (10 µg/mL) of cefuroxime. Our results suggest that beta-lactam antibiotic exposure may act as a signaling molecule that promotes transformation into the biofilm phenotype. Loss of viable bacteria, increase in biofilm biomass and decreased protein production coupled with a concomitant up-regulation of genes involved with glycogen production might result in a biofilm of sessile, metabolically inactive bacteria sustained by stored glycogen. These biofilms may protect surviving bacteria from subsequent antibiotic challenges, and act as a reservoir of viable bacteria once antibiotic exposure has ended.

Canadian clinical practice guidelines for acute and chronic rhinosinusitis

This document provides healthcare practitioners with information regarding the management of acute rhinosinusitis (ARS) and chronic rhinosinusitis (CRS) to enable them to better meet the needs of this patient population. These guidelines describe controversies in the management of acute bacterial rhinosinusitis (ABRS) and include recommendations that take into account changes in the bacteriologic landscape. Recent guidelines in ABRS have been released by American and European groups as recently as 2007, but these are either limited in their coverage of the subject of CRS, do not follow an evidence-based strategy, or omit relevant stakeholders in guidelines development, and do not address the particulars of the Canadian healthcare environment.

Advances in understanding the pathophysiology of CRS, along with the development of appropriate therapeutic strategies, have improved outcomes for patients with CRS. CRS now affects large numbers of patients globally and primary care practitioners are confronted by this disease on a daily basis. Although initially considered a chronic bacterial infection, CRS is now recognized as having multiple distinct components (eg, infection, inflammation), which have led to changes in therapeutic approaches (eg, increased use of corticosteroids). The role of bacteria in the persistence of chronic infections, and the roles of surgical and medical management are evolving. Although evidence is limited, guidance for managing patients with CRS would help practitioners less experienced in this area offer rational care. It is no longer reasonable to manage CRS as a prolonged version of ARS, but rather, specific therapeutic strategies adapted to pathogenesis must be developed and diffused.

Guidelines must take into account all available evidence and incorporate these in an unbiased fashion into management recommendations based on the quality of evidence, therapeutic benefit, and risks incurred. This document is focused on readability rather than completeness, yet covers relevant information, offers summaries of areas where considerable evidence exists, and provides recommendations with an assessment of strength of the evidence base and degree of endorsement by the multidisciplinary expert group preparing the document.

These guidelines have been copublished in both Allergy, Asthma & Clinical Immunology and the Journal of Otolaryngology-Head and Neck Surgery.

Effectiveness of amoxicillin/clavulanate potassium in the treatment of acute bacterial sinusitis in children

OBJECTIVE

The role of antibiotic therapy in managing acute bacterial sinusitis (ABS) in children is controversial. The purpose of this study was to determine the effectiveness of high-dose amoxicillin/potassium clavulanate in the treatment of children diagnosed with ABS.

METHODS

This was a randomized, double-blind, placebo-controlled study. Children 1 to 10 years of age with a clinical presentation compatible with ABS were eligible for participation. Patients were stratified according to age (<6 or >or=6 years) and clinical severity and randomly assigned to receive either amoxicillin (90 mg/kg) with potassium clavulanate (6.4 mg/kg) or placebo. A symptom survey was performed on days 0, 1, 2, 3, 5, 7, 10, 20, and 30. Patients were examined on day 14. Children's conditions were rated as cured, improved, or failed according to scoring rules.

RESULTS

Two thousand one hundred thirty-five children with respiratory complaints were screened for enrollment; 139 (6.5%) had ABS. Fifty-eight patients were enrolled, and 56 were randomly assigned. The mean age was 66 +/- 30 months. Fifty (89%) patients presented with persistent symptoms, and 6 (11%) presented with nonpersistent symptoms. In 24 (43%) children, the illness was classified as mild, whereas in the remaining 32 (57%) children it was severe. Of the 28 children who received the antibiotic, 14 (50%) were cured, 4 (14%) were improved, 4 (14%) experienced treatment failure, and 6 (21%) withdrew. Of the 28 children who received placebo, 4 (14%) were cured, 5 (18%) improved, and 19 (68%) experienced treatment failure. Children receiving the antibiotic were more likely to be cured (50% vs 14%) and less likely to have treatment failure (14% vs 68%) than children receiving the placebo.

CONCLUSIONS

ABS is a common complication of viral upper respiratory infections. Amoxicillin/potassium clavulanate results in significantly more cures and fewer failures than placebo, according to parental report of time to resolution of clinical symptoms.

Antimicrobial-resistant Streptococcus pneumoniae: trends and management

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

Oral garenoxacin in the treatment of acute bacterial maxillary sinusitis: a Phase II, multicenter, noncomparative, open-label study in adult patients undergoing sinus aspiration

BACKGROUND

Garenoxacin is a des-F(6)-quinolone with in vitro activity against key respiratory pathogens, including Streptococcus pneumoniae, Hemophilus influenzae, Staphylococcus aureus, and Moraxella catarrhalis. Limited data are available regarding the effect of garenoxacin in the treatment of acute bacterial sinusitis.

OBJECTIVE

The aim of this study was to assess the efficacy and tolerability of garenoxacin in adults with acute bacterial maxillary sinusitis undergoing a pre-treatment diagnostic sinus aspirate.

METHODS

This Phase II, multicenter, noncomparative, open-label study was conducted at 30 centers in the United States, Mexico, Argentina, and Europe. Male and female patients aged 18 to 80 years with clinical signs and symptoms lasting >or=5 but <or=28 days and radiologic signs (air-fluid level, opacification, mucosal thickening) of acute maxillary sinusitis were eligible. The entry criteria for the 5-day treatment regimen did not include mucosal thickening of >or=5 mm because it was believed that improvement in mucosal thickening might not be reliably measurable at the 5-day time point. All patients received garenoxacin 400 mg QD for 5 or 10 days. Maxillary sinus needle aspiration for Gram stain, routine culture, and susceptibility testing were performed before treatment, and, if clinically indicated, during and after treatment. Bacteriologic eradication (negative culture on repeat sinus aspiration) and cure rates (complete resolution of all signs and symptoms) were assessed at a test-of-cure visit 5 to 18 days after the end of treatment. The occurrence of adverse events was recorded by the investigators up to 30 days after the last administration of garenoxacin by questioning patients.

RESULTS

A total of 546 patients were enrolled and 543 were randomized (5-day cohort: mean age, 40 years; mean weight, 76 kg; 56% women; 10-day cohort: mean age, 41 years; mean weight, 77 kg; 58% women). Clinically evaluable patients included 253 in the 5-day cohort and 266 in the 10-day cohort. Cure rates were 93% (236/253; 95% CI, 89%-96%) and 91% (243/266; 95% CI, 87%-94%) for evaluable patients in the 5- and 10-day cohorts, respectively. Bacteriologic eradication rates in microbiologically evaluable patients were 94% in both cohorts (5 days, 204/217; 10 days, 182/193). Eradication rates in the 5- and 10-day cohorts were as follows: S pneumoniae, 94% (62/66) and 93% (39/42); H influenzae, 100% (30/30) and 93% (26/28); S aureus, 96% (23/24) and 91% (31/34); and M catarrhalis, 89% (8/9) and 86% (12/14). Of the 9 patients with acute bacterial sinusitis due to multidrug-resistant S pneumoniae, 8 achieved clinical cure with garenoxacin treatment. Adverse events (AEs) most frequently reported were diarrhea (<or=2%), nausea (2%-6%), headache (2%-6%), and dizziness (<or=2%). Two percent of patients withdrew because of an AE (allergic reaction, adverse gastrointestinal effects, dyspnea, dizziness, headache, or elevation in liver enzymes).

CONCLUSION

In this population of patients with signs and symptoms of acute maxillary sinusitis, oral garenoxacin 400 mg QD for 5 or 10 days eradicated 94% of bacterial pathogens associated with acute bacterial sinusitis in this population and appeared to be well tolerated in adults.

A computer-controlled ultrasound pulser-receiver system for transskull fluid detection using a shear wave transmission technique

The purpose of this study was to evaluate the performance of a computer-controlled ultrasound pulser-receiver system incorporating a shear mode technique for transskull fluid detection. The presence of fluid in the sinuses of an ex vivo human skull was examined using a pulse-echo method by transmitting an ultrasound beam through the maxilla bone toward the back wall on the other side of the sinus cavity. The pulser was programmed to generate bipolar pulse trains with 5 cycles at a frequency of 1 MHz, repetition frequency of about 20 Hz, and amplitude of 100 V to drive a 1-MHz piezoelectric transducer. Shear and longitudinal waves in the maxilla bone were produced by adjusting the bone surface incident angle to 45 degrees and 0 degrees, respectively. Computer tomography (CT) scans of the skull were performed to verify the ultrasound experiment. Using the shear mode technique, the echo waveform clearly distinguishes the presence of fluid, and the estimated distance of the ultrasound traveled in the sinus is consistent with the measurement from the CT images. Contrarily, using the longitudinal mode, no detectable back wall echo was observed under the same conditions. As a conclusion, this study demonstrated that the proposed pulser-receiver system with the shear mode technique is promising for transskull fluid detecting, such as mucus in a sinus.

Judicious antibiotic use and intranasal corticosteroids in acute rhinosinusitis

Most patients with symptoms of acute rhinosinusitis are treated with antibiotics. However, many cases of rhinosinusitis are secondary to viral infections and unlikely to benefit from antibiotic therapy. Inappropriate use of antibiotics in patients with acute nonbacterial rhinosinusitis contributes to the increase in bacterial antibiotic resistance. Consequently, safe and effective alternatives to antibiotics are needed in the treatment of acute rhinosinusitis caused by viral infections. Recent results from controlled trials have shown that intranasal corticosteroids, used in combination with antibiotics or as monotherapy in selected cases, provide significant symptom relief and resolution of acute rhinosinusitis. The use of intranasal corticosteroids in acute rhinosinusitis therefore might reduce the inappropriate use of antimicrobial therapy in acute rhinosinusitis.

Moxifloxacin vs amoxicillin/clavulanate in the treatment of acute sinusitis

PURPOSE

The aim of this study was to compare the efficacy and safety of moxifloxacin with that of amoxicillin/clavulanate for the treatment of acute bacterial sinusitis in adults.

MATERIALS AND METHODS

Five hundred seventy-five patients from Latin American countries were randomized to receive oral moxifloxacin 400 mg once daily for 7 days, or oral amoxicillin/clavulanate 500/125 mg 3 times daily for 10 days, in a prospective, open study.

RESULTS

At the test-of-cure visit (7-14 days after the end of therapy), the clinical success rate in the moxifloxacin group was 93.4% similar to that in the amoxicillin/clavulanate group (92.7%). Documented bacteriological eradication plus presumed eradication rates in the moxifloxacin (96.5%) and the amoxicillin/clavulanate (96.7%) groups were also similar. Drug-related adverse events were recorded in 32.2% of patients in the moxifloxacin group and 29.7% in the amoxicillin/clavulanate group. Patient discontinuation in the trial due to adverse events occurred for 10 patients in the moxifloxacin group and 6 in the amoxicillin/clavulanate group.

CONCLUSIONS

Overall, in terms of clinical and bacteriological response, moxifloxacin was equivalent to amoxicillin/clavulanate for the treatment of acute bacterial sinusitis in adults.

Making the call: the diagnosis of acute community-acquired bacterial sinusitis

BACKGROUND

Although one of the most common illnesses encountered in the primary care setting, acute community-acquired bacterial sinusitis (ACABS) can be a challenge to diagnose.

METHODS

Existing diagnostic modalities ranging from clinical history to imaging studies used to diagnose ACABS are discussed.

RESULTS

Numerous methods exist but they do not distinguish well between viral and bacterial illness.

CONCLUSION

Diagnosis of ACABS should primarily be made based on the clinical history. Other modalities provide useful information in select cases.

Optimizing the management of community-acquired respiratory tract infections in the age of antimicrobial resistance

Community-acquired respiratory tract infections (CARTIs) are the most common reason for prescribing antibiotics in the primary care setting. However, over the last decade, the management of CARTIs has become increasingly complicated by the steady increase in prevalence of drug-resistant pathogens responsible for these infections. As a result, significant attention has been directed at understanding the mechanisms of pathogen acquisition of resistance, drivers of resistance and methods for preventing the development of resistance. Data from recent surveillance studies suggest a slowing or decline in resistance rates to agents, such as beta-lactams, macrolides, tetracyclines and folic acid metabolism inhibitors. However, resistance to one antimicrobial family--the fluoroquinolones--while still low, appears to be on the increase. This is of significant concern given the rapid increase in resistance noted with older antibiotics in recent history. While the clinical implications of antibacterial resistance are poorly understood, the overall rates of antimicrobial resistance, as reported in recent surveillance studies, do not correspond to current rates of failure in patients with CARTIs. This disconnection between laboratory-determined resistance and clinical outcome has been termed the in vitro-in vivo paradox and several explanations have been offered to explain this phenomenon. Solving the problem of antimicrobial resistance will be multifactorial. Important factors in this effort include the education of healthcare providers, patients and the general healthcare community regarding the hazards of inappropriate antibiotic use, prevention of infections through vaccination, development of accurate, inexpensive and timely point-of-care diagnostic tests to aid in patient assessment, institution of objective treatment guidelines and use of more potent agents, especially those with a focused spectrum of activity, earlier in the treatment of CARTIs as opposed to reserving them as second-line treatment options. Ultimately, the single-most important factor will be the judicious use of antibiotics, as fewer antibiotic prescriptions lead to fewer antimicrobial-resistant bacteria.

Macrolide immunomodulatory effects and symptom resolution in acute exacerbation of chronic bronchitis and acute maxillary sinusitis: a focus on clarithromycin

Bacterial respiratory tract infections are common in the primary care setting and patients often seek the assistance of a healthcare professional in order to achieve resolution of their symptoms. Antibiotic agents that offer rapid symptom relief, in addition to excellent bacteriological and clinical cure, are highly desired. Macrolides have proven to be highly effective in treating acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis. In addition, immunomodulatory effects that may contribute to symptom resolution have been reported. This article reviews current literature on symptom resolution in acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis, with a focus on clarithromycin, and explores the potential mechanisms that may contribute to this action.

Pathogen shifts and changing cure rates for otitis media and tonsillopharyngitis

Pneumococcal conjugate vaccine use has caused a decrease in the incidence of recurrent and refractory acute otitis media in the United States and a shift in the predominant pathogens. Now Haemophilus influenzae is the most commonly isolated organism (about 60% of the total), and more than half the strains make beta-lactamase, rendering them resistant to amoxicillin. Penicillin nonsusceptible pneumococci, the main target of antibiotic therapy in the 1990s, has become a much less common isolate (10%- 25% of the total). These changes impact antibiotic selection for acute otitis media. Penicillin treatment of group A streptococcal tonsillopharyngitis does not meet the minimum United States Food and Drug Administration standards for first-line treatment, which is 85% or greater eradication at the end of therapy. Recent results with amoxicillin suggest its efficacy is also waning. Cephalosporins have the highest bacteriologic and clinical efficacy. This has implications for optimal antibiotic therapy.

Telithromycin in the treatment of pneumococcal community-acquired respiratory tract infections: a review

OBJECTIVES

A pooled analysis of 14 Phase III studies was performed to establish the clinical and bacteriologic efficacy of telithromycin 800 mg once daily in the treatment of pneumococcal community-acquired respiratory tract infections (RTIs).

METHODS

Data were examined from 5534 adult/adolescent patients with community-acquired pneumonia (CAP), acute exacerbations of chronic bronchitis (AECB), or acute bacterial sinusitis, who had received telithromycin for 5-10 days or a comparator antibacterial.

RESULTS

Streptococcus pneumoniae was identified in 704/2060 (34.2%) bacteriologically evaluable patients. The respective per-protocol clinical cure rates for telithromycin and comparators were 94.3% and 90.0% (CAP); 81.5% and 78.9% (AECB); 90.1% and 87.5% (acute sinusitis); 92.7% and 87.6% (all indications). Clinical cure rates were 28/34 (82.4%) and 5/7, respectively, for penicillin-resistant infections, and 44/52 (84.6%) and 11/14, respectively, for erythromycin-resistant infections. Of 82 patients with pneumococcal bacteremia, 74 (90.2%) were clinically cured after telithromycin treatment, including 5/7 and 8/10 with penicillin- or erythromycin-resistant strains, respectively. Adverse events considered possibly related to study medication were reported by 1071/4045 (26.5%) telithromycin and 505/1715 (29.4%) comparator recipients. These events were generally of mild/moderate severity, and mainly gastrointestinal in nature.

CONCLUSIONS

As S. pneumoniae is the leading bacterial cause of community-acquired RTIs, and antibacterial resistance is increasing among this species, these findings support the use of telithromycin as first-line therapy in this setting.

Management of acute bacterial rhinosinusitis: current issues and future perspectives

Acute bacterial rhinosinusitis (ABRS), which manifests as an inflammation of at least one of the paranasal sinuses, is a major public health issue in developed countries. Diagnosis and treatment of ABRS can pose significant challenges in clinical practice, including difficulty in differentiation between viral and bacterial infection and a lack of simple, reliable and convenient methods for definitive diagnosis. Treatment choice is also a challenge because a decision is typically made empirically; therefore, the selection of therapy should be based on knowledge of local patterns of antimicrobial resistance, spectrum of activity against the most common ABRS pathogens (including those that are resistant to penicillins and macrolides) and pharmacodynamic potency. Current guidelines for diagnosis and treatment of ABRS in various countries share some similarities but also have important differences. Criteria for making the clinical diagnosis of sinusitis vary only slightly from country to country, while recommendations of therapy reflect the local impact of bacterial resistance.

Bacteriological efficacy of 5-day therapy with telithromycin in acute maxillary sinusitis

Increasing resistance among the key pathogens responsible for community-acquired respiratory tract infections, namely Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, has the potential to limit the effectiveness of the antibacterial agents available to treat these infections. Moreover, there are regional differences in the susceptibility patterns observed and, as treatment is usually empirical, choosing an effective treatment can be challenging. Telithromycin, the first ketolide to be approved for clinical use, offers an activity profile that covers the key respiratory pathogens including penicillin- and macrolide-resistant S. pneumoniae as well as beta-lactamase-producing H. influenzae and M. catarrhalis. In a pooled analysis of three large controlled clinical trials involving patients with acute maxillary sinusitis, the bacteriological efficacy of 5- or 10-day treatment with telithromycin and 10-day treatment with comparators was evaluated. Telithromycin administered as a once-daily 800 mg dose for 5 days achieved eradication rates of 91.8, 87.5 and 92.9% for S. pneumoniae, H. influenzae and M. catarrhalis, respectively. Bacteriological eradication of 8/10 and 12/14 isolates of S. pneumoniae resistant to penicillin and erythromycin, respectively, was also reported following 5-day treatment with telithromycin. The clinical efficacy of this regimen was equivalent to that of a 10-day regimen of telithromycin or standard 10-day courses of amoxicillin-clavulanic acid or cefuroxime axetil. Telithromycin 800mg given for 5 days was well tolerated, with the majority of adverse events being of mild or moderate intensity. These data suggest that telithromycin provides effective first-line therapy for use in patients with acute maxillary sinusitis in a short and convenient once-daily dosage regimen.

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.

Beta-lactam antibiotics: newer formulations and newer agents

beta-Lactam antibiotics share a common structure and mechanism of action, although they differ in their spectrum of antimicrobial activity and utility in treating different infections. The current classes include the penicillins, the penicillinase-resistant penicillins, the extended- spectrum penicillins, the cephalosporins, the carbapenems, and the monobactams. This article discusses some of the newest beta-lactams available for use in the United States: ertapenem, cefditoren, and cefepime. A new formulation of amoxicillin-clavulanate, which contains higher doses of amoxicillin, is also discussed.

Comparative in vitro activity of a pharmacokinetically enhanced oral formulation of amoxicillin/clavulanic acid (2000/125 mg twice daily) against 9172 respiratory isolates collected worldwide in 2000

OBJECTIVES

A new, pharmacokinetically enhanced, oral formulation of amoxicillin/clavulanic acid has been developed to overcome resistance in the major bacterial respiratory pathogen Streptococcus pneumoniae, while maintaining excellent activity against Haemophilus influenzae and Moraxella catarrhalis, including beta-lactamase producing strains. This study was conducted to provide in vitro susceptibility data for amoxicillin/clavulanic acid and 16 comparator agents against the key respiratory tract pathogens.

METHODS

Susceptibility testing was performed on 9172 isolates collected from 95 centers in North America, Europe, Australia, and Hong Kong by broth microdilution MIC determination, according to NCCLS methods, using amoxicillin/clavulanic acid and 16 comparator antimicrobial agents. Results were interpreted according to NCCLS breakpoints and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints based on oral dosing regimens.

RESULTS

Overall, 93.5% of Streptococcus pneumoniae isolates were susceptible to amoxicillin/clavulanic acid at the current susceptible breakpoint of < or =2 microg/mL and 97.3% at the PK/PD susceptible breakpoint of < or =4 microg/mL for the extended release formulation. Proportions of isolates that were penicillin intermediate and resistant were 13% and 16.5%, respectively, while 25% were macrolide resistant and 21.8% trimethoprim/sulfamethoxazole resistant. 21.9% of Haemophilus influenzae were beta-lactamase producers and 16.8% trimethoprim/sulfamethoxazole resistant, >99% of isolates were susceptible to amoxicillin/clavulanic acid, cefixime, ciprofloxacin and levofloxacin at NCCLS breakpoints. The most active agents against Moraxella catarrhalis were amoxicillin/clavulanic acid, macrolides, cefixime, fluoroquinolones, and doxycycline. Overall, 13% of Streptococcus pyogenes were resistant to macrolides.

CONCLUSION

The extended release formulation of amoxicillin/clavulanic acid has potential for empiric use against many respiratory tract infections worldwide due to its activity against species resistant to many agents currently in use.

Efficacy and safety of oral telithromycin once daily for 5 days versus moxifloxacin once daily for 10 days in the treatment of acute bacterial rhinosinusitis

OBJECTIVE

To compare the clinical and bacteriologic efficacy and safety of short-duration treatment with telithromycin given for 5 days with moxifloxacin given for 10 days in adults with acute bacterial rhinosinusitis (ABRS).

STUDY DESIGN

In this prospective, double-blind, parallel-group, randomized, multicenter study, adult patients (N = 349) with ABRS were randomized to oral telithromycin (800 mg once daily for 5 days) or to oral moxifloxacin (400 mg once daily for 10 days) and followed for 31 to 36 days. Clinical outcome was determined by the investigator at the posttherapy/test of cure (TOC) visit. Bacteriologic outcome was determined by comparing cultures taken at the pretreatment visit with cultures obtained at the posttherapy/TOC visit. The primary objective was to demonstrate equivalence of clinical cure rates in the per-protocol population between treatment groups at the posttherapy/TOC visit.

RESULTS

Clinical success at TOC (primary endpoint) was achieved in 87.4% of patients in the telithromycin group compared with 86.9% for moxifloxacin (per-protocol patients; 0.5% difference between treatment groups; 95% confidence interval [CI], -8.1, 9.2; P = 0.8930). The bacteriologic success rates were 94.1% and 93.9%, respectively (0.2% difference between treatment groups; 95% CI, -14.2, 14.5; P = 0.9734). Overall treatment-emergent adverse events for both drugs (mostly gastrointestinal) were mild to moderate in intensity.

CONCLUSION AND SIGNIFICANCE

The clinical and bacteriologic efficacy of telithromycin 800 mg once daily for 5 days was equivalent to that of moxifloxacin 400 mg once daily for 10 days, establishing telithromycin as an important treatment option for ABRS.

Endoscopy versus radiography for the diagnosis of acute bacterial rhinosinusitis

The aim of the study was to estimate the sensitivity and specificity of endoscopy and the diagnostic value of clinical criteria for acute bacterial rhinosinusitis (ABRS). The hospital records of 117 consecutive patients who had symptoms compatible with ABRS and who underwent sinus radiography and flexible nasendoscopy were retrieved. A positive diagnosis was entertained when radiography demonstrated air fluid level, complete opacification or at least 6 mm mucosal thickening and/or endoscopy revealed purulent material within the drainage area of the sinuses. Using a modified version of the Hui and Walter procedure, the sensitivity and specificity of nasendoscopy was calculated against sinus radiography, a standard reference test, with known estimated sensitivity (76%) and specificity (79%). The findings show that 40 patients (34%) had positive endoscopy and radiography. Twenty patients (17%) had positive endoscopy and negative radiography, and vice versa in 15 (13%). In 42 patients (36%) both modalities were negative. Endoscopy yielded a sensitivity of 80% (95% CI, 0.55-1.00) and a specificity of 94% (95% CI, 0.33-1.00). Although estimates seem better than those of radiography, the confidence intervals are quite wide and no firm conclusion is drawn. Neither single nor combination of symptoms, concurrent with two major and one minor factor advocated by the AAO-HNS Task Force on Rhinosinusitis, were associated with a positive diagnosis of ABRS. The data suggest that endoscopy is no less effective than radiography in predicting ABRS, also that clinical criteria are of rather limited diagnostic value, and thus should be supported by other diagnostic tests. Endoscopy is recommended as a first line diagnostic tool for the diagnosis of ABRS in routine ENT practice. If the outcome is negative, radiography may follow.

The microbiology and antimicrobial resistance patterns in chronic rhinosinusitis

OBJECTIVES

The purpose of this study was to review the microbiology of chronic rhinosinusitis (CRS) in patients undergoing endoscopic sinus surgery (ESS) and comment on antimicrobial resistance trends.

METHODS

A retrospective review of 101 patients undergoing ESS during the period of 1997 to 2001 was performed. Patients were divided into groups based on their surgical history. Fifty-five patients without prior ESS history were placed in the primary group; 46 patients who had undergone prior ESS were placed in the revision group. Intraoperative microbiology culture data were reviewed and antimicrobial resistance data analyzed.

RESULTS

Data on 101 patients were analyzed. There were 182 total cultures sent, yielding 257 isolates. The most common isolates were coagulase-negative Staphylococcus (SCN) (45% of cultures), gram-negative rods (25% of cultures), and Staphylococcus aureus (24% of cultures). Pseudomonas aeruginosa was isolated in 9% of cultures. When comparing the 2 patient groups, we did not find consistent trends in the differences in the prevalence of these isolates. Antimicrobial resistance for SCN (P = .01) and S aureus (P < .001) was greater in the revision surgery. Overall, 62% of patients were found to have at least 1 isolate with decreased antibiotic sensitivity.

CONCLUSION

The most prevalent microorganisms in patients with CRS are SCN, S aureus, and gram-negative rods. Perhaps more importantly, the antimicrobial sensitivities of these microorganisms appear to be a growing problem. These findings suggest increased antimicrobial resistance in patients undergoing revision ESS when compared with patients undergoing surgery for the first time.

Treatment of acute bacterial rhinosinusitis caused by antimicrobial-resistant Streptococcus pneumoniae

Acute bacterial rhinosinusitis (ABRS) is a secondary bacterial infection of the nose and paranasal sinuses, usually preceded by a viral upper respiratory infection or allergy, with symptoms that have not improved after 10 days or that have worsened after 5 to 7 days. Streptococcus pneumoniae and Haemophilus influenzae are the most common causes of ABRS in adults. Increasing rates of antimicrobial resistance among S. pneumoniae and beta-lactamase production among H. influenzae are formidable challenges to the successful treatment of infections caused by these organisms. To this end, various formulations of amoxicillin-clavulanate have been developed, the most recent of which is pharmacokinetically enhanced and provides a total daily dose of 4,000 mg of amoxicillin and 250 mg of clavulanate. This formulation has been shown to be safe and effective in the treatment of infections caused by penicillin-resistant S. pneumoniae (minimum inhibitory concentration 2 microg/mL); the clavulanate component provides adequate coverage of beta-lactamase-producing pathogens.

Antimicrobial susceptibility patterns of Streptococcus pneumoniae in Mexico

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

Back-up antibiotic prescriptions could reduce unnecessary antibiotic use in rhinosinusitis

OBJECTIVES

To examine the attitudes of patients with rhinosinusitis toward the availability of "back-up" antibiotics, and potential implications for antibiotic use rates.

STUDY DESIGN AND SETTING

A survey that assessed actual and hypothetical antibiotic prescription patterns was administered to a convenience sample of patients treated for rhinosinusitis in one acute care facility between September 1 and December 1, 2001.

RESULTS

Of 386 eligible patients, 114 completed the survey. Seventy-six percent of patients expected antibiotic treatment; satisfaction rates were significantly associated with receiving an antibiotic prescription (P <.05). Over two-thirds of patients (69.7%) reported preference for back-up antibiotic prescriptions in the future, with 91.1% stating they would wait at least 1 day, and 52.7% at least 7 days, to fill a backup prescription. In sensitivity analysis, back-up prescriptions significantly reduced antibiotic use over a wide range of assumptions.

CONCLUSIONS

The majority of patients with rhinosinusitis in this study expected antibiotic prescriptions, and were more satisfied if they were received. Back-up antibiotics have the potential to reduce unnecessary antibiotic use, mitigate risk of nontreatment, and preserve high levels of patient satisfaction.

Introduction: standards of antibacterial performance

The development and clinical use of antimicrobial agents continue to evolve in line with new science, understanding and needs. While antimicrobial resistance remains an important determinant for drug development and therapeutic choice, pharmacokinetic and pharmacodynamic parameters are having an ever-increasing importance in defining performance targets for new and established agents. Recently licensed new therapies are largely directed at serious hospital-associated Gram-positive infections, whereas in the community, therapeutic choice remains dependent on well-established agents from limited classes of antimicrobials. In order to maximise the benefits from such agents, it is appropriate that dosage regimens and antibacterial choices be reviewed in the light of new knowledge, particularly in the area of pharmacokinetics and pharmacodynamics. Antimicrobial resistance continues to evolve, notably within respiratory pathogens, therefore steps must be taken to maintain optimum therapeutic outcomes and also limit the development and spread of resistant strains. Whilst changes in patient and physician attitudes and behaviour towards better quality prescribing are important, new agents must also be developed to provide adequate coverage for resistant pathogens. Development times for novel agents and classes of antimicrobials are long, with uncertain safety profiles and chances of success. Thus, the development of new formulations of existing agents, designed to overcome current resistance patterns, constitutes a potentially important additional strategy towards appropriate prescribing.

Diagnosis and management of acute otitis media

This evidence-based clinical practice guideline provides recommendations to primary care clinicians for the management of children from 2 months through 12 years of age with uncomplicated acute otitis media (AOM). The American Academy of Pediatrics and American Academy of Family Physicians convened a committee composed of primary care physicians and experts in the fields of otolaryngology, epidemiology, and infectious disease. The subcommittee partnered with the Agency for Healthcare Research and Quality and the Southern California Evidence-Based Practice Center to develop a comprehensive review of the evidence-based literature related to AOM. The resulting evidence report and other sources of data were used to formulate the practice guideline recommendations. The focus of this practice guideline is the appropriate diagnosis and initial treatment of a child presenting with AOM. The guideline provides a specific definition of AOM. It addresses pain management, initial observation versus antibacterial treatment, appropriate choices of antibacterials, and preventive measures. Decisions were made based on a systematic grading of the quality of evidence and strength of recommendations, as well as expert consensus when definitive data were not available. The practice guideline underwent comprehensive peer review before formal approval by the partnering organizations. This clinical practice guideline is not intended as a sole source of guidance in the management of children with AOM. Rather, it is intended to assist primary care clinicians by providing a framework for clinical decision-making. It is not intended to replace clinical judgment or establish a protocol for all children with this condition. These recommendations may not provide the only appropriate approach to the management of this problem.

Quality of Life in Treatment of Acute Rhinosinusitis with Clarithromycin and Amoxicillin/Clavulanate

OBJECTIVES

Clarithromycin and amoxicillin/clavulanate (A/C) are first line antibiotics used to treat uncomplicated acute rhinosinusitis (ARS). This study examined the efficacy of clarithromycin and A/C for the treatment of ARS relative to the patient's quality of life (QOL).

STUDY DESIGN

Twenty-two patients with uncomplicated ARS were randomly assigned treatment (single blinded relative to the investigator) using clarithromycin or A/C. Patients underwent assessment to confirm the diagnosis and treatment outcome at the initial screening and on completion of antibiotics (diagnosis + 14 days and 28 days). QOL was evaluated using the Allergy Outcomes Survey (AOS), the Rhinoconjunctivitis QOL Questionnaire (RQLQ), the Short Form 36 survey (SF-36), an instantaneous six-item Symptom Severity Survey (SSS-6), and a Visual Analogue Scale (VAS). Surveys were completed at the time of diagnosis, on completion of antibiotics, and at 28 days after diagnosis.

RESULTS

Twenty patients completed the study. The SSS-6 and the RQLQ demonstrated significant improvement for all patients at week 4 (P =.002 and P =.003, respectively). The SSS-6 demonstrated significant improvement for clarithromycin at 14 days (P =.02) and at 28 days (P =.029), whereas A/C patients demonstrated significant improvement in symptoms only at 28 days (P =.046). The RQLQ, which reflects the previous 2 weeks, demonstrated significant improvement for the A/C patients at 28 days (P =.01). The Allergy Survey, the SF-36, and the VAS failed to demonstrate significant improvement in the combined data analysis.

CONCLUSIONS

Clarithromycin and A/C were equally effective in treating ARS. The clarithromycin patients felt better more rapidly (at 14 days), but both groups of patients had long-term improvement in symptoms at 28 days.

Endoscopic surgery for frontal sinusitis–a graduated approach

Contemporary surgical treatment of patients with frontal sinusitis is based on a graduated approach determined by the patient's history and the extent of disease present. Most patients with inflammatory disease of the frontal sinus respond well to an anterior ethmoidectomy and clearing of agger nasi cells encroaching upon the frontal recess. In more advanced cases, a frontal sinusotomy with enlargement of the ostium may be performed to facilitate frontal sinus drainage and ventilation. For patients in whom conventional endoscopic techniques have not been successful, the floor of the frontal sinus is removed with a drill, usually with the assistance of image-guidance technology. Frontal sinus obliteration is reserved for patients with advanced disease for whom endoscopic management has been unsuccessful. Although patients with refractory frontal sinusitis can present a therapeutic challenge, proper surgical management usually results in successful control of symptoms and overall improvement in quality of life.

Effect of adenoidectomy in children with complex problems of rhinosinusitis and associated diseases

OBJECTIVES

The effectiveness of adenoidectomy in the management of pediatric sinusitis is still a controversial issue. The size of the adenoid and associated diseases are the factors for consideration. The adenoid has been studied and is proved to be a probable source of infection for the paranasal sinus. The purpose of this study is to evaluate the efficacy of adenoidectomy in reducing the frequency of sinusitis in children.

METHODS

A prospective study was done in pediatric patients with rhinosinusitis admitted for adenoidectomy from January 2000 to January 2002. Pre-operative frequency of rhinosinusitis, underlying diseases and the diseases caused by the adenoid were recorded. The adenoid size was evaluated by lateral skull X-ray. The patients were followed after surgery and frequency of rhinosinusitis and associated diseases were compared with the pre-operative period.

RESULTS

There were 37 patients with mean age of 6+/-2.8 years. Mean duration for pre-operative review was 436.7 days and mean duration for post-operative follow up was 450.2 days. Almost all (92%) of the patients had obstructive sleep disorder and 88.2% had adenoid-nasopharyngeal ratio >0.7. There was a statistically significant reduction of episodes per year of rhinosinusitis and obstructive sleep disorder after surgery (P-value < 0.001 and 0.008, respectively).

CONCLUSIONS

Adenoidectomy was proved to be effective in the management of pediatric rhinosinusitis in this series. Adenoidectomy should be most beneficial as a surgical option before endoscopic sinus surgery (ESS), especially in younger children with obstructive symptoms.

Microbiology and antimicrobial management of sinusitis

The growing resistance to antimicrobial agents of all respiratory tract bacterial pathogens has made the management of sinusitis more difficult. The upper respiratory tract including the nasopharynx serves as the reservoir for pathogenic bacteria that can cause respiratory infections including sinusitis. During a viral respiratory infection, potential pathogens can relocate from the nasopharynx into the sinus cavity, causing sinusitis. Establishment of the correct microbiology of all forms of sinusitis is of primary importance, because it can serve as a guide for choosing the adequate antimicrobial therapy. This article summarizes the current information regarding the microbiology of all forms of sinusitis and approaches to antimicrobial therapy.

Antibacterial resistance among children with community-acquired respiratory tract infections (PROTEKT 1999-2000)

OBJECTIVE

To determine the susceptibility of bacterial respiratory tract pathogens, isolated from children (0-12 years) as part of the global PROTEKT surveillance study (1999-2000), to a range of antibacterials, including the ketolide telithromycin.

METHODS

Minimum inhibitory concentrations of the antibacterials studied were determined at a central laboratory using the NCCLS microdilution broth method. Macrolide resistance mechanisms were detected by PCR.

RESULTS

Of 779 Streptococcus pneumoniae isolates worldwide, 43% were non-susceptible to penicillin (18% intermediate; 25% resistant) and 37% were resistant to erythromycin, with considerable intercountry variation. Eighteen per cent of 653 Haemophilus influenzae and >90% of 316 Moraxella catarrhalis isolates produced beta-lactamase. Of 640 Streptococcus pyogenes isolates, 10% were resistant to erythromycin, with considerable intercountry variation. All S. pneumoniae and 99.8% of H. influenzae isolates were susceptible to telithromycin using breakpoints proposed to the NCCLS (<or=1 and <or=4 mg/L, respectively). All M. catarrhalis and 97% of S. pyogenes and isolates were susceptible to <or=1 mg/L telithromycin.

CONCLUSIONS

Antibacterial resistance complicates the empirical treatment of respiratory tract infections in children and requires continued monitoring. Telithromycin may be a useful therapeutic alternative as it is highly active against strains exhibiting various resistance phenotypes.

Asthma, allergy, and upper airway disease

The practitioner must be aware of the strong interrelationship between asthma, allergy, eczema, otitis media, viral upper respiratory infection, and sinusitis. When allergy, eczema, otitis media (particularly after the age of 2 years), viral upper respiratory infection, or sinusitis is present in a patient, asthma must be considered as possible sequelae. If a patient has symptoms of intermittent or persistent asthma, consideration must be given to the presence of allergy, eczema, otitis media, viral upper respiratory infection, or sinusitis as comorbid conditions or possible triggers for the asthma symptoms. Failure to evaluate the entire upper and lower airway for these interrelated conditions will result in incomplete treatment and incomplete symptom relief [61]. This article reviews the strong association between diseases of the upper and lower airway [62,63]. Treatment and control of upper airway symptoms is essential for control of asthma symptoms. Control of allergy, eczema, otitis, sinusitis, and viral symptoms result in improved outcomes for asthma patients. Reduction of these asthma triggers and comorbid conditions is also likely to reduce asthma medication requirements while improving symptoms status.

Clinical pharmacodynamics of antifungals

Application of pharmacodynamic principles to antifungal drugs has provided an understanding of the relationship between drug dosing and treatment outcomes similar to that observed in antibacterial pharmacodynamics. Initial observations with triazole pharmacodynamics have correlated with clinical trial results and proved useful for validation of in vitro susceptibility breakpoints. Pharmacodynamic studies have been invaluable for clinical trial dosing design for numerous antibacterial drugs in the development stage. More recently, pharmacodynamics has been used for the development of treatment guidelines. Although there remain many unanswered questions regarding antifungal pharmacodynamics, available data suggest usefulness in the application of pharmacodynamics to antifungal clinical development.

Antimicrobial resistance among pediatric respiratory tract infections: clinical challenges

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

Antimicrobial treatment guidelines for acute bacterial rhinosinusitis

Treatment guidelines developed by the Sinus and Allergy Health Partnership for acute bacterial rhinosinusitis (ABRS) were originally published in 2000. These guidelines were designed to: (1) educate clinicians and patients (or patients’ families) about the differences between viral and bacterial rhinosinusitis; (2) reduce the use of antibiotics for nonbacterial nasal/sinus disease; (3) provide recommendations for the diagnosis and optimal treatment of ABRS; (4) promote the use of appropriate antibiotic therapy when bacterial infection is likely; and (5) describe the current understanding of pharmacokinetic and pharmacodynamics and how they relate to the effectiveness of antimicrobial therapy. The original guidelines are updated here to include the most recent information on management principles, antimicrobial susceptibility patterns, and therapeutic options.

Burden of disease

An estimated 20 million cases of ABRS occur annually in the United States. According to National Ambulatory Medical Care Survey (NAMCS) data, sinusitis is the fifth most common diagnosis for which an antibiotic is prescribed. Sinusitis accounted for 9% and 21% of all pediatric and adult antibiotic prescriptions, respectively, written in 2002. The primary diagnosis of sinusitis results in expenditures of approximately $3.5 billion per year in the United States.

Definition and diagnosis of ABRS

ABRS is most often preceded by a viral upper respiratory tract infection (URI). Allergy, trauma, dental infection, or other factors that lead to inflammation of the nose and paranasal sinuses may also predispose individuals to developing ABRS.

Patients with a “common cold” (viral URI) usually report some combination of the following symptoms: sneezing, rhinorrhea, nasal congestion, hyposmia/anosmia, facial pressure, postnasal drip, sore throat, cough, ear fullness, fever, and myalgia. A change in the color or the characteristic of the nasal discharge is not a specific sign of a bacterial infection. Bacterial superinfection may occur at any time during the course of a viral URI. The risk that bacterial superinfection has occurred is greater if the illness is still present after 10 days. Because there may be cases that fall out of the “norm” of this typical progression, practicing clinicians need to rely on their clinical judgment when using these guidelines. In general, however, a diagnosis of ABRS may be made in adults or children with symptoms of a viral URI that have not improved after 10 days or worsen after 5 to 7 days. There may be some or all of the following signs and symptoms: nasal drainage, nasal congestion, facial pressure/pain (especially when unilateral and focused in the region of a particular sinus), postnasal drainage, hyposmia/anosmia, fever, cough, fatigue, maxillary dental pain, and ear pressure/fullness.

Physical examination provides limited information in the diagnosis of ABRS.

While sometimes helpful, plain film radiographs, computed tomography (CT), and magnetic resonance imaging scans are not necessary for cases of ABRS.

Microbiology of ABRS

The most common bacterial species isolated from the maxillary sinuses of patients with ABRS are Streptococcus pneumoniae , Haemophilus influenzae , and Moraxella catarrhalis , the latter being more common in children. Other streptococcal species, anaerobic bacteria and Staphylococcus aureus cause a small percentage of cases.

Bacterial resistance in ABRS

The increasing prevalence of penicillin nonsusceptibility and resistance to other drug classes among S pneumoniae has been a problem in the United States, with 15% being penicillin-intermediate and 25% being penicillin-resistant in recent studies. Resistance to macrolides and trimethoprim/sulfamethoxazole (TMP/SMX) is also common in S pneumoniae . The prevalence of β-lactamase-producing isolates of H influenzae is approximately 30%, while essentially all M catarrhalis isolates produce β-lactamases. Resistance of H influenzae to TMP/SMX is also common.

Antimicrobial treatment guidelines for ABRS

These guidelines apply to both adults and children. When selecting antibiotic therapy for ABRS, the clinician should consider the severity of the disease, the rate of progression of the disease, and recent antibiotic exposure. The guidelines now divide patients with ABRS into two general categories: (1) those with mild symptoms who have not received antibiotics within the past 4 to 6 weeks, and (2) those with mild disease who have received antibiotics within the past 4 to 6 weeks or those with moderate disease regardless of recent antibiotic exposure. The difference in severity of disease does not imply infection with a resistant pathogen. Rather, this terminology indicates the relative degree of acceptance of possible treatment failure and the likelihood of spontaneous resolution of symptoms—patients with more severe symptoms are less likely to resolve their disease spontaneously. The primary goal of antibiotic therapy is to eradicate bacteria from the site of infection, which, in turn, helps (1) return the sinuses back to health; (2) decrease the duration of symptoms to allow patients to resume daily activities more quickly; (3) prevent severe complications such as meningitis and brain abscess; and (4) decrease the development of chronic disease. Severe or life-threatening infections with or without complications are rare, and are not addressed in these guidelines.

Prior antibiotic use is a major risk factor associated with the development of infection with antimicrobial-resistant strains. Because recent antimicrobial exposure increases the risk of carriage of and infection due to resistant organisms, antimicrobial therapy should be based upon the patient’s history of recent antibiotic use. The panel’s guidelines, therefore, stratify patients according to antibiotic exposure in the previous 4 to 6 weeks.

Lack of response to therapy at ≥72 hours is an arbitrary time established to define treatment failures. Clinicians should monitor the response to antibiotic therapy, which may include instructing the patient to call the office or clinic if symptoms persist or worsen over the next few days.

The predicted bacteriologic and clinical efficacy of antibiotics in adults and children has been determined according to mathematical modeling of ABRS developed by Michael Poole, MD, PhD, based on pathogen distribution, resolution rates without treatment, and in vitro microbiologic activity.

Antibiotics can be placed into the following relative rank order of predicted clinical efficacy for adults: 90% to 92% = respiratory fluoroquinolones (gatifloxacin, levofloxacin, moxifloxacin), ceftriaxone, high-dose amoxicillin/clavulanate (4 g/250 mg/day), and amoxicillin/clavulanate (1.75 g/250 mg/day); 83% to 88% = high-dose amoxicillin (4 g/day), amoxicillin (1.5 g/day), cefpodoxime proxetil, cefixime (based on H influenzae and M catarrhalis coverage), cefuroxime axetil, cefdinir, and TMP/SMX; 77% to 81% = doxycycline, clindamycin (based on gram-positive coverage only), azithromycin, clarithromycin and erythromycin, and telithromycin; 65% to 66% = cefaclor and loracarbef. The predicted spontaneous resolution rate in patients with a clinical diagnosis of ABRS is 62%.

Antibiotics can be placed into the following relative rank order of predicted clinical efficacy in children with ABRS: 91% to 92% = ceftriaxone, high-dose amoxicillin/clavulanate (90 mg/6.4 mg per kg per day) and amoxicillin/clavulanate (45 mg/6.4 mg per kg per day); 82% to 87% = high-dose amoxicillin (90 mg/kg per day), amoxicillin (45 mg/kg per day), cefpodoxime proxetil, cefixime (based on H influenzae and M catarrhalis coverage only), cefuroxime axetil, cefdinir, and TMP/SMX; and 78% to 80% = clindamycin (based on gram-positive coverage only), cefprozil, azithromycin, clarithromycin, and erythromycin; 67% to 68% = cefaclor and loracarbef. The predicted spontaneous resolution rate in untreated children with a presumed diagnosis of ABRS is 63%.

Recommendations for initial therapy for adult patients with mild disease (who have not received antibiotics in the previous 4 to 6 weeks) include the following choices: amoxicillin/clavulanate (1.75 to 4 g/250 mg per day), amoxicillin (1.5 to 4 g/day), cefpodoxime proxetil, cefuroxime axetil, or cefdinir. While TMP/SMX, doxycycline, azithromycin, clarithromycin, erythromycin, or telithromycin may be considered for patients with β-lactam allergies, bacteriologic failure rates of 20% to 25% are possible. Failure to respond to antimicrobial therapy after 72 hours should prompt either a switch to alternate antimicrobial therapy or reevaluation of the patient (see Table 4).When a change in antibiotic therapy is made, the clinician should consider the limitations in coverage of the initial agent.

Recommendations for initial therapy for adults with mild disease who have received antibiotics in the previous 4 to 6 weeks or adults with moderate disease include the following choices: respiratory fluoroquinolone (eg, gatifloxacin, levofloxacin, moxifloxacin) or high-dose amoxicillin/clavulanate (4 g/250 mg per day). The widespread use of respiratory fluoroquinolones for patients with milder disease may promote resistance of a wide spectrum of organisms to this class of agents. Ceftriaxone (parenteral, 1 to 2 g/day for 5 days) or combination therapy with adequate gram-positive and negative coverage may also be considered. Examples of appropriate regimens of combination therapy include high-dose amoxicillin or clindamycin plus cefixime, or high-dose amoxicillin or clindamycin plus rifampin. While the clinical effectiveness of ceftriaxone and these combinations for ABRS is unproven; the panel considers these reasonable therapeutic options based on the spectrum of activity of these agents and on data extrapolated from acute otitis media studies. Rifampin should not be used as monotherapy, casually, or for longer than 10 to 14 days, as resistance quickly develops to this agent. Rifampin is also a well-known inducer of several cytochrome p450 isoenzymes and therefore has a high potential for drug interactions. Failure of a patient to respond to antimicrobial therapy after 72 hours of therapy should prompt either a switch to alternate antimicrobial therapy or reevaluation of the patient (see Table 4). When a change in antibiotic therapy is made, the clinician should consider the limitations in coverage of the initial agent. Patients who have received effective antibiotic therapy and continue to be symptomatic may need further evaluation. A CT scan, fiberoptic endoscopy or sinus aspiration and culture may be necessary.

Recommendations for initial therapy for children with mild disease and who have not received antibiotics in the previous 4 to 6 weeks include the following: high-dose amoxicillin/clavulanate (90 mg/6.4 mg per kg per day), amoxicillin (90 mg/kg per day), cefpodoxime proxetil, cefuroxime axetil, or cefdinir. TMP/SMX, azithromycin, clarithromycin, or erythromycin is recommended if the patient has a history of immediate Type I hypersensitivity reaction to β-lactams. These antibiotics have limited effectiveness against the major pathogens of ABRS and bacterial failure of 20% to 25% is possible. The clinician should differentiate an immediate hypersensitivity reaction from other less dangerous side effects. Children with immediate hypersensitivity reactions to β-lactams may need: desensitization, sinus cultures, or other ancillary procedures and studies. Children with other types of reactions and side effects may tolerate one specific β-lactam, but not another. Failure to respond to antimicrobial therapy after 72 hours should prompt either a switch to alternate antimicrobial therapy or reevaluation of the patient (see Table 5).When a change in antibiotic therapy is made, the clinician should consider the limitations in coverage of the initial agent.

The recommended initial therapy for children with mild disease who have received antibiotics in the previous 4 to 6 weeks or children with moderate disease is high-dose amoxicillin/clavulanate (90 mg/6.4 mg per kg per day). Cefpodoxime proxetil, cefuroxime axetil, or cefdinir may be used if there is a penicillin allergy (eg, penicillin rash); in such instances, cefdinir is preferred because of high patient acceptance. TMP/SMX, azithromycin, clarithromycin, or erythromycin is recommended if the patient is β-lactam allergic, but these do not provide optimal coverage. Clindamycin is appropriate if S pneumoniae is identified as a pathogen. Ceftriaxone (parenteral, 50 mg/kg per day for 5 days) or combination therapy with adequate gram-positive and -negative coverage may also be considered. Examples of appropriate regimens of combination therapy include high-dose amoxicillin or clindamycin plus cefixime, or high-dose amoxicillin or clindamycin plus rifampin. The clinical effectiveness of ceftriaxone and these combinations for ABRS is unproven; the panel considers these reasonable therapeutic options based on spectrum of activity and on data extrapolated from acute otitis media studies. Rifampin should not be used as monotherapy, casually, or for longer than 10 to 14 days as resistance quickly develops to this agent. Failure to respond to antimicrobial therapy after 72 hours of therapy should prompt either a switch to alternate antimicrobial therapy or reevaluation of the patient (see Table 5). When a change in antibiotic therapy is made, the clinician should consider the limitations in coverage of the initial agent. Patients who have received effective antibiotic therapy and continue to be symptomatic may need further evaluation. A CT scan, fiberoptic endoscopy or sinus aspiration and culture may be necessary.

In vitro activities of ABT-492, a new fluoroquinolone, against 155 aerobic and 171 anaerobic pathogens isolated from antral sinus puncture specimens from patients with sinusitis

ABT-492 exhibited excellent in vitro activities against all 326 aerobic and anaerobic antral puncture sinus isolates tested with MICs (in micrograms per milliliter) at which 90% of the isolates tested were inhibited as follows: Haemophilus influenzae, 0.001; Moraxella catarrhalis, 0.008; and Streptococcus pneumoniae, 0.015. It was four- to sixfold more active than other fluoroquinolones, including against levofloxacin-resistant strains of S. pneumoniae, methicillin-resistant Staphylococcus aureus, and Prevotella species.

Basic pharmacodynamics of antibacterials with clinical applications to the use of β-lactams, glycopeptides, and linezolid

Time above MIC for free drug concentrations is the important PK-PD parameter correlating with the efficacy of beta-lactam antibiotics. The duration of time plasma concentrations needed to exceed the MIC is relatively similar for most organisms except staphylococci. Neutrophils contribute very little to the overall activity of beta-lactams. The appearance of increasing antimicrobial resistance can challenge the efficacy of these drugs when concentrations do not exceed the MIC for 40% to 50% of the dosing interval. Time above MIC with oral amoxicillin and amoxicillin-clavulanate can be enhanced with high-dose formulations. Time above MIC with parenteral preparations can be enhanced by longer intravenous infusions or even continuous infusion. The 24-hour AUC-MIC is probably the important PK-PD parameter correlating with the efficacy of vancomycin and teicoplanin. It clearly is the important parameter for the efficacy of linezolid. Usual doses of these drugs generally provide adequate plasma concentrations to treat effectively infections in which plasma concentrations are predictive of tissue concentrations. Penetration of these drugs into respiratory secretions, such as ELF, is enhanced for linezolid and reduced for vancomycin. This may give linezolid an advantage over vancomycin in certain respiratory infections.

Rhinosinusitis: review from a dental perspective

Patients often present to their dental providers with reports of posterior maxillary pain. The etiology of their symptoms may be either an acute or chronic situation, and the examining dentist's primary focus is usually to rule out dental pathosis. Rhinosinusitis should be an important consideration on the list of differential diagnoses when evaluating patients with posterior maxillary pain. The American Academy of Otolaryngology standardized the terminology for paranasal sinus infections in 1996 and offered guidelines for evaluation and treatment of sinusitis. This article highlights these guidelines for diagnosing and treating patients with rhinosinusitis. It also includes a review of sinus anatomy and of the special considerations for iatrogenic sinus exposure as well. Dental providers who understand the relationship between the maxillary sinus and the oral structures are better prepared to arrive at an accurate diagnosis. The astute dental provider will ensure a rapid and positive outcome for this group of patients with rhinosinusitis.