The spread of multiply resistant Streptococcus pneumoniae at a day care center in Ohio

Improving diagnostic testing and reducing overuse of antibiotics for children with pharyngitis: a useful role for the electronic medical record

BACKGROUND

Because of rising resistance to antibiotics, appropriate use of antibiotics is an important measure of quality of care. The purpose of this study was to use an electronic medical record (EMR) to assess use of diagnostic testing and of antibiotics for pharyngitis in a pediatric outpatient setting and to target areas for improvement.

METHODS

Using data retrieved from the EMR, we analyzed visits from March 1, 2001 to February 28, 2002 for children 3 to 18 years old diagnosed with pharyngitis. We determined the proportion of episodes with a diagnostic test for group A streptococci, the proportion for which a prescription for an antibiotic was dispensed and factors that predicted prescribing and testing.

RESULTS

Of 391 episodes of pharyngitis, a test was ordered for 303 (78%). Antibiotics were prescribed for 90 (23%); for 76 of 90 (84%) a test was ordered. Clinicians were less likely to order tests late in the week [relative risk (RR), 0.76; 95% confidence interval (CI), 0.66, 0.87)], more likely to order tests for patients with an exudate (RR 1.2; 95% CI 1.1, 1.3) and more likely to prescribe an antibiotic for patients with an exudate (RR 1.5; 95% CI 1.1, 2.1). When prescribing an antibiotic clinicians were less likely to order tests late in the week (RR 0.1; 95% CI 0.02, 0.5) and for patients diagnosed with scarlet fever (RR 0.07; 95% CI 0.01, 0.4).

CONCLUSION

Using data from the EMR, we could assess adherence to the guidelines for antibiotic use and identify areas to target for improving diagnostic testing and reducing overuse of antibiotics in our clinic.

Macrolide resistance: an increasing concern for treatment failure in children

BACKGROUND

Antimicrobial treatment of pediatric respiratory tract infections has evolved during the past 30 years as a result of antimicrobial resistance. The focus of antimicrobial therapy in these conditions has shifted from penicillins to other agents because of the dramatic increase in antimicrobial resistance among common respiratory pathogens, including Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. It is important for clinicians to understand how resistance develops so that they can help prevent this phenomenon from occurring with other antimicrobials.

METHODS

This article reviews the published literature on resistance to macrolide antimicrobials among common pediatric respiratory tract pathogens and clinical and bacteriologic outcomes of infections with these pathogens.

RESULTS

Resistance among common pediatric respiratory tract pathogens to macrolides occurs through two main mechanisms, alteration of the target site and active efflux. Although resistance patterns vary by geographic region, the widespread use of macrolides has contributed to the emergence of both types of macrolide-resistant organisms. Conditions that favor the selection and proliferation of resistant strains include children with repeated, close contact who frequently receive antimicrobial treatment or prophylaxis, such as children who attend day care. Recent US surveillance data show that 20 to 30% of S. pneumoniae are resistant to macrolides, with approximately two-thirds of macrolide-resistant strains associated with an efflux mechanism and the remainder associated with a ribosomal methylase. Additionally, although less well-known, virtually all strains of H. influenzae have an intrinsic macrolide efflux pump. As resistance to macrolides has increased, clinical failures have resulted, and these agents are no longer considered appropriate for empiric first line antimicrobial therapy of acute otitis media and sinusitis unless patients are truly penicillin-allergic. Therefore, other antimicrobials are recommended for the empiric treatment of children with respiratory tract infections, including higher doses of amoxicillin and amoxicillin/clavulanate (90 mg/kg/day amoxicillin), cefuroxime axetil and intramuscular ceftriaxone.

CONCLUSIONS

As resistance to macrolides increases and clinical failures in children become more common with this class of antimicrobials, judicious use of antimicrobials is needed. This includes limiting antimicrobial use for viral infections and using the most effective agents when antimicrobials are clinically indicated, such as higher doses of amoxicillin and amoxicillin/clavulanate. Application of these principles may prevent proliferation and further development of resistance.

Antibacterial cleaning and hygiene products as an emerging risk factor for antibiotic resistance in the community

Antibiotic resistance within the community setting is an emerging public-health concern. Infection with antibiotic-resistant organisms in the community among people lacking traditional risk factors has been reported. In addition, prevalence studies have identified individuals carrying antibiotic-resistant organisms in the absence of known risk factors. These studies strongly suggest the presence of contributing factors that have yet to be identified. In this paper we review the burden of antibiotic resistance and known risk factors within the community setting, assess the potential role of antibacterial cleaning and hygiene products containing triclosan in the emergence of resistance, and recommend future research on the assessment of household cleaning and hygiene products containing triclosan.

EURISWEB--Web-based epidemiological surveillance of antibiotic-resistant pneumococci in day care centers

BACKGROUND

EURIS (European Resistance Intervention Study) was launched as a multinational study in September of 2000 to identify the multitude of complex risk factors that contribute to the high carriage rate of drug resistant Streptococcus pneumoniae strains in children attending Day Care Centers in several European countries. Access to the very large number of data required the development of a web-based infrastructure - EURISWEB - that includes a relational online database, coupled with a query system for data retrieval, and allows integrative storage of demographic, clinical and molecular biology data generated in EURIS.

METHODS

All components of the system were developed using open source programming tools: data storage management was supported by PostgreSQL, and the hypertext preprocessor to generate the web pages was implemented using PHP. The query system is based on a software agent running in the background specifically developed for EURIS.

RESULTS

The website currently contains data related to 13,500 nasopharyngeal samples and over one million measures taken from 5,250 individual children, as well as over one thousand pre-made and user-made queries aggregated into several reports, approximately. It is presently in use by participating researchers from three countries (Iceland, Portugal and Sweden).

CONCLUSION

An operational model centered on a PHP engine builds the interface between the user and the database automatically, allowing an easy maintenance of the system. The query system is also sufficiently adaptable to allow the integration of several advanced data analysis procedures far more demanding than simple queries, eventually including artificial intelligence predictive models.

Influence of child care on nasopharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae

BACKGROUND

Children cared for by a child minder (CM) should be less exposed to upper respiratory tract infections than those in group day care (GDC) and therefore to antibiotic treatment. Thus fewer CM children should carry resistant bacteria. To test this hypothesis nasopharyngeal carriage of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI) and exposure to recent antibiotic treatment were investigated among children in both types of care settings in the Alpes Maritimes (France) between November 1999 and March 2000.

METHODS AND POPULATION

A two stage cluster sample of children attending group day care or cared for by a child minder was selected. Nasopharyngeal samples were cultured for SP and HI. Penicillin susceptibility was tested by disk diffusion and E-test and beta-lactamase production.

RESULTS

We sampled 235 children in the CM group and 298 in the GDC group who were ages 6 to 36 months. Age and sex distribution were similar in both groups. S. pneumoniae was isolated in 80 children in the CM group (34.0%) and in 163 (54.7%) children in GDC (P < 10-6). Proportions of non-penicillin susceptible (NPSP) were 52.5 and 55.8%, respectively (P = 0.6). H. influenzae was present in 37.2% of children in GDC vs. 23.8% in the CM group (P < 0.001). Proportions of beta-lactamase-positive HI (HIBL+) were 40.2% vs. 46.4%, respectively (P = 0.4). Antibiotic exposure during the previous 3 months occurred in 41.3% of children in GDC and in 47.4% in the CM group (P = 0.16). There was no association between antibiotic use and carriage of NPSP or HIBL+ strains.

CONCLUSION

SP and HI carriage rates were significantly lower among children in the CM group than in GDC. The proportion of NPSP and HIBL+ was similar in both groups, and comparable patterns of antibiotic use were observed. Continued efforts must concentrate on parental education and enforcement of recommendations for management of pediatric upper respiratory tract infections.

Vaccination of day-care center attendees reduces carriage of Streptococcus pneumoniae among their younger siblings

AIM

We conducted a study to determine whether administration of a pneumococcal conjugate vaccine to toddlers attending day-care centers (DCCs) could prevent acquisition of Streptococcus pneumoniae of the vaccine serotypes (VT) by their younger siblings.

METHODS

In a double blind study, 262 DCC attendees ages 12 to 35 months were randomized to receive a 9-valent pneumococcal conjugate vaccine (PnCRM9; n = 132), or a control vaccine (meningococcus C vaccine; n = 130). It was planned to follow the groups for 2 years with monthly nasopharyngeal pneumococcal cultures during the first follow-up year and every 2 months during the second year. Forty-six younger siblings of the above described children, age <18 months (23 siblings of the PnCRM9 recipients and 23 of the controls), were also enrolled, and nasopharyngeal cultures were obtained monthly until the children reached the age of 18 months or started to attend DCC, if before the age of 18 months. Pneumococcal isolates were serotyped and tested for antibiotic susceptibility.

RESULTS

Of the 3748 cultures obtained from the DCC attendees, 2450 (65%) were positive for S. pneumoniae. Of 306 cultures obtained from the younger siblings, 151 (49%) were positive. Among the PnCRM9 recipients, cultures were significantly less frequently positive for the VT S. pneumoniae than among the controls (13% vs. 21%, respectively; P < 0.001). The same pattern was seen in the younger siblings of PnCRM9 recipients vs. the siblings of controls (21% vs. 34%, respectively; P = 0.017). The reverse trend was seen for non-VT strains in both the DCC attendees (44% vs. 34%, respectively; P < 0.001) and their younger siblings (19% vs. 13%, respectively; P = 0.15). There was a significant decrease in the carriage rate of antibiotic-resistant S. pneumoniae in both the PnCRM9 recipients and their younger siblings. The relative risks (and 95% confidence intervals) to carry S. pneumoniae penicillin-nonsusceptible, resistant to > or =1, > or =2 and > or =3 antibiotic categories among younger siblings of PnCRM9 recipients vs. siblings of controls were 0.47 (0.31 to 0.70), 0.49 (0.33 to 0.71), 0.46 (0.30 to 0.73) and 0.49 (0.21 to 1.17), respectively. When acquired, VT and antibiotic-resistant S. pneumoniae were carried for a significantly shorter period of time among siblings of PnCRM9 recipients than in siblings of controls.

CONCLUSION

The marked effect of PnCRM9 administration to DCC attendees on carriage of VT and antibiotic-resistant S. pneumoniae among their younger household close contacts demonstrates a herd effect of the vaccine.

Factors associated with penicillin-nonsusceptible pneumococcal infections in Brazil

Resistance of Streptococcus pneumoniae is a worldwide, growing problem. Studies of factors associated with resistance to penicillin have not been conducted in Brazil. The objective of the present study was to evaluate factors associated with infection by S. pneumoniae not susceptible to penicillin. A prevalence study was conducted including all patients with a positive culture for S. pneumoniae in a hospital from July 1991 to December 1992 and the year 1994. Of 165 patients identified, 139 were considered to have clinically relevant infections and 88% of them had invasive infections. All infections were community acquired and consisted of pneumonia (44%) and of central nervous system (19%), pelvic or abdominal (12%), upper airway or ocular (12%), primary bloodstream (9%) and skin and soft tissue (5%) infections. Mortality was 25%. Susceptibility to penicillin was present in 77.6% of the isolates; 21.8% were relatively resistant, and one isolate was resistant (minimal inhibitory concentration = 4 micro g/ml). Multivariate analysis showed that age below 4 years (odds ratio (OR): 3.53, 95% confidence interval (95%CI): 1.39-8.96) and renal failure (OR: 5.50, 95%CI: 1.07-28.36) were associated with lack of susceptibility to penicillin. Bacteremia occurred significantly less frequently in penicillin-nonsusceptible infections (OR: 0.34, 95%CI: 0.14-0.84), possibly suggesting that lack of penicillin susceptibility is associated with lower virulence in S. pneumoniae.

Effect of a nonavalent conjugate vaccine on carriage of antibiotic-resistant Streptococcus pneumoniae in day-care centers

BACKGROUND

In the developed societies, day-care centers (DCCs) play an important role in the spread of antibiotic-resistant pneumococci both within the facility and from the facility to the community. This study was conducted to determine the effect of a nonavalent pneumococcal conjugate vaccine (PCV-9) on the carriage of antibiotic-resistant pneumococci in the DCC.

SUBJECTS AND METHODS

Healthy DCC attendees ages 12 to 35 months were randomized to receive either PCV-9 or a control vaccine (conjugate meningococcus C vaccine) in a double blinded manner. Nasopharyngeal Streptococcus pneumoniae cultures were obtained from each subject before vaccination, monthly during the first year of follow-up and every 2 to 3 months during the second year of follow-up. For each isolate the serotype and antibiotic susceptibility were determined.

RESULTS

A total of 132 and 130 evaluable toddlers received either PCV-9 or the control vaccine, respectively. In total 3748 cultures were obtained, of which 2450 (65%) were positive for S. pneumoniae. The resistance rates to penicillin, trimethoprim-sulfamethoxazole and erythromycin were 36, 35 and 16%, respectively. Resistance rates to > or =1 and > or =3 antibiotic categories were 52 and 9%, respectively. Antibiotic resistance was found mainly in the 5 serotypes included in the pneumococcal conjugate vaccines (6B, 9V, 14, 19F and 23F) and in 2 related serotypes (6A and 19A). In the vaccinated group a clear and significant reduction of the carriage rate of the serotypes included in the vaccine and the related serotype 6A as well as an increase in the carriage rate of the serotypes not included in the vaccine were observed. In parallel a significant decrease in carriage rate of antibiotic-resistant pneumococci was observed. The reduction of carriage of antibiotic-resistant pneumococci was seen in all age windows but was greater in the age window <36 months.

CONCLUSIONS

The carriage rate of antibiotic-resistant S. pneumoniae, including multiply resistant S. pneumoniae, in DCC attendees is high. Pneumococcal conjugate vaccines seem to be an important tool for reducing the carriage rate of antibiotic-resistant pneumonia in DCCs.

Resistance in respiratory tract pathogens and antimicrobial use in Icelandic and Lithuanian children

To assess resistance rates among respiratory tract pathogens and antimicrobial usage of children in Iceland and Lithuania, and to correlate usage patterns with resistance rates, nasopharyngeal swabs were taken from healthy children attending day-care centres in Reykjavik (n = 6) and Vilnius (n = 13), and cultured for pneumococci, Haemophilus influenzae and Moraxella catarrhalis. Information about recent antimicrobial use was obtained by a questionnaire. 50% and 51% carried pneumococci, 59% and 67% carried H. influenzae and 60% and 46% carried M. catarrhalis, in Reykjavik (n = 297) and Vilnius (n = 508), respectively. The prevalence of penicillin non-susceptible pneumococci was 11% in Reykjavik (mainly serotype 6B) and 5% in Vilnius (mainly 23F). At the time of sampling 3% of the children in Reykjavik and 8% in Vilnius were receiving antimicrobials. Children carrying penicillin non-susceptible pneumococci had used antimicrobials more frequently in the preceding month and this was significant for the Icelandic children (p < 0.0002). Antimicrobial use was more common in Vilnius than in Reykjavik, yet antimicrobial resistance was more common in Reykjavik. Resistance rates cannot be predicted only on the basis of recent antimicrobial use.

Antimicrobial drug prescription in ambulatory care settings, United States, 1992-2000

During the 1990s, as antimicrobial resistance increased among pneumococci, many organizations promoted appropriate antimicrobial use to combat resistance. We analyzed data from the National Ambulatory Medical Care Survey, an annual sample survey of visits to office-based physicians, and the National Hospital Ambulatory Medical Care Survey, an annual sample survey of visits to hospital emergency and outpatient departments, to describe trends in antimicrobial prescribing from 1992 to 2000 in the United States. Approximately 1,100-1,900 physicians reported data from 21,000-37,000 visits; 200-300 outpatient departments reported data for 28,000-35,000 visits; approximately 400 emergency departments reported data for 21,000-36,000 visits each year. In that period, the population- and visit-based antimicrobial prescribing rates in ambulatory care settings decreased by 23% and 25%, respectively, driven largely by a decrease in prescribing by office-based physicians. Antimicrobial prescribing rates changed as follows: amoxicillin and ampicillin, -43%; cephalosporins, -28%; erythromycin, -76%; azithromycin and clarithromycin, +388%; quinolones, +78%; and amoxicillin/clavulanate, +69%. This increasing use of azithromycin, clarithromycin, and quinolones warrants concern as macrolide- and fluoroquinolone-resistant pneumococci are increasing.

Epidemiology of invasive pneumococcal infection in Taiwan: antibiotic resistance, serogroup distribution, and ribotypes analyses

From July, 1998, to June, 1999, pneumococcal isolates from 288 patients with invasive disease in Taiwan were serogrouped and tested for their susceptibility to various antibiotics. Automated ribotyping was used to study their molecular epidemiology. The mortality rate among those > or = 65 years was higher than those 18 or 19-64 years (p < 0.001). The total incidence of infection was significantly higher during the cooler season than the warmer season (p = 0.017). Among strains isolated from children aged < or = 18 years, 76% were not susceptible to penicillin, a rate that was significantly higher (p < 0.001) than that for adults (45%), as was the susceptibility to azithromycin, erythromycin, and trimethoprim-sulfamethoxazole (p < 0.005). The most prevalent serogroup encountered in the invasive isolates was 23, followed by 6, 14, 19, and 3. Isolation of Streptococcus pneumoniae in cerebrospinal fluid was at high rate in children under 5 years (p = 0.00012). Molecular typing revealed a high degree of polymorphism among the isolates. Among serogroup 23 and 19 isolates, a high proportion had the same ribotypes, the Taiwan23F-15 and Taiwan19F-14 isolates, suggesting the circulation of a Taiwanese epidemic strain. In Taiwan, S. pneumoniae isolates should be tested for their resistance profile for children < or = 18 years old, as these are more likely to harbor high-level resistance. Control of pneumococcal infection with the 7-valent-conjugated vaccine should also be considered because it is estimated that it would cover nearly 90% of the serotypes among pediatric invasive disease.

Epidemiology of neonatal infections: experience during and after hospitalization

OBJECTIVE

We assessed the epidemiology of neonatal infections coming to medical attention among inpatient and outpatient newborn infants within a defined health care maintenance organization (HMO) population.

DESIGN AND METHODS

This was a retrospective cohort study, using automated data from a large health maintenance organization and the hospital where the majority of HMO patients delivered. All infants delivered between October 1, 1990 and March 31, 1998 at the study hospital and receiving postdischarge care at the study HMO for the first 30 days of life were included. The outcomes assessed were 10 neonatal infection syndromes defined according to modified National Nosocomial Infection System criteria.

RESULTS

There were 13 224 infants in the study cohort. Of these, 559 infants (4.2%) had 574 infections. Nonpneumonia respiratory infections were most common, accounting for 43% of all infections. Infections diagnosed in the outpatient setting comprised 63% of all infections. More serious infections (bloodstream infection, clinical sepsis and pneumonia) were typically diagnosed in the first few days of life and before nursery discharge. Infants with an infection had a significantly longer length of nursery stay (4.7 excess days among full term infants, P < 0.001), more office visits (397.3 vs. 273.3 per 100, P < 0.001) and more hospital admissions (16.7 vs. 3.6 per 100, P = 0.001) than uninfected infants.

CONCLUSION

Infections were common during the first 30 days of life. The majority were noninvasive, were diagnosed in the outpatient setting and were most likely community-acquired. Serious infections were rare, occurred early in the neonatal period and were usually diagnosed before nursery discharge.

Examining influences of pharmacists' communication with consumers about antibiotics

A national study was conducted of community pharmacists to examine influences on their communication with consumers about antibiotics and antibiotic resistance. The objective was twofold: to explore the nature of barriers that might be changed to allow pharmacists greater participation in educational campaigns, and to discover which variables would best predict communication using a modification of the Theory of Reasoned Action model. Whereas most pharmacists agreed that their role in educating patients is important, they also noted several barriers prevent them from engaging in campaigns, such as time constraints, lack of educational materials, and fear of harming relations with physicians. Pharmacists' discussion about antibiotics in general was predicted primarily by attitudes about their role and efficacy, by their autonomy, and by enabling measures-such as pamphlets-that would better aid them in participating in a judicious antibiotic use campaign. Discussion about resistance was predicted by attitudes and enabling measures.

Moving from recommendation to implementation and audit: part 2. Review of interventions and audit

There are multiple interventions available that may help to control the development and spread of resistance to antimicrobial agents in bacteria implicated in community-acquired respiratory tract infections. Unfortunately, very few studies have assessed the effectiveness of these interventions using objective end-points, such as reduction in resistance rates and improvement in clinical outcomes. Most interventions are centered on reducing inappropriate or unnecessary use of antibiotics; others focus on reducing disease burden and bacterial colonization. With regard to antibiotic use, efforts should be concentrated at both the prescriber and consumer levels. Interventions that target prescribers include: provision of educational materials; strategies and tools to improve diagnosis; implementation of practice guidelines; personalized interactive sessions with feedback on the practice profile; and use of delayed prescription and alternative prescribing strategies. Optimal results are usually obtained when these interventions are combined with consumer education. Regulatory interventions (e.g. licensing regulations and controlled access to drugs), restrictions in the use of agents for growth promotion in animals, and use of nonantimicrobial therapies (e.g. probiotics) may help further to reduce inappropriate antibiotic use and thereby decrease the selective pressure for development of resistance. Infection-control strategies, public health measures, vaccination programs, and new antibiotics all have a role in minimizing the spread of resistant organisms. Ideally, resistance-control programs should include predefined criteria for success and integral audit processes based on objective end-points (antibiotic use, resistance trends, and health outcomes). Standardization of data collection is imperative so that the relative merits of various interventions can be compared. Effective implementation and audit of interventions is often difficult in developing countries owing to poor health-care infrastructures, lack of resources, poor education/training, and minimal regulatory controls on the supply and quality of antimicrobials. Substantial support from governments and health-care organizations across the globe is required to initiate and sustain effective intervention programs to control antimicrobial resistance.

Antimicrobial use and serotype distribution of nasopharyngeal Streptococcus pneumoniae isolates recovered from Greek children younger than 2 years old

The serotype distribution of 781 nasopharyngeal pneumococcal isolates recovered from 2448 unselected children aged 2-23 months was studied. Only 3.9% of the children for whom cultures were performed attended day care centers. The proportions of pneumococcal isolates that belonged to serotypes related to the 7-, 9- and 11-valent conjugate pneumococcal vaccine were 65%, 66%, and 70%, respectively. The pneumococcal carriage rate among untreated children was 34%; the rates among children treated with antibiotics during the periods 1-30 or 31-60 days before the time of nasopharyngeal sampling were 25% and 36%, respectively. There was a significant positive association between antimicrobial use and carriage of antibiotic-resistant pneumococci, which belonged mainly to vaccine-related serotypes. The proportion of isolates that belonged to vaccine-related serotypes in untreated carriers was 72%; however, the proportions in carriers treated 1-30 days or 31-60 days before sampling were 66% and 56%, respectively. In the nasopharynx, antimicrobial use selects for antibiotic-resistant pneumococci, mainly of vaccine-related serotypes, whereas it may promote an increase in the frequency of colonization with nonvaccine serotypes.

Meningitis and encephalitis in children. An update

Over the course of the past decade, much has changed on the landscape of meningitis and encephalitis in children. West Nile virus has emerged in the United States as a new etiologic pathogen causing encephalitis. Human herpesvirus-6 has been identified as a cause of encephalitis and febrile seizures. Lymphocytic choriomeningitis virus has been identified as an underrecognized neuroteratogen. The emergence of penicillin-resistant Streptococcus pneumoniae has complicated the treatment of bacterial meningitis, whereas the Haemophilus influenzae vaccine has fundamentally altered the disease's epidemiology. The recognition that much of the neuropathologic change induced by bacterial meningitis is inflammation mediated has paved the way to the demonstration that dexamethasone can substantially improve the outcome of bacterial meningitis in children. Although much progress has been made toward understanding, treating, and preventing these important infections, much remains to be learned.

Narrow versus broad spectrum antibacterials: factors in the selection of pneumococcal resistance to beta-lactams

Streptococus pneumoniae represents an interesting model to discuss the relative impact of broad versus narrow spectrum antibacterials as potential selectors for resistance. Indeed, this pathogen is responsible for potentially severe infections in the community, and has a great capacity for acquisition of resistance to antibacterial agents. It has been the focus of many studies to elucidate some unique aspects of molecular biology, including the adaptive mechanisms responsible for emergence and spread of multiresistance. In the past, the use of narrow spectrum agents was recommended in order to try to reduce the risk of selection of resistance. This concept is nowadays somewhat obsolete for several reasons. S. pneumoniae is able to acquire resistance to antibacterials belonging to different families of drugs through different molecular mechanisms. Thus, selection of multiresistant pneumococci can result from exposure to very different agents, including narrow spectrum as well as broad spectrum agents. In vitro studies have shown a different potential for selection of resistance among the beta-lactam agents. Furthermore, several studies have more or less directly established a close relationship between the level of antibacterial use and the rate of selection of resistance. In addition to the overall amount of antibacterials prescribed in the community, several other factors have been shown to influence the rate of selection of resistance, including the use of doses that are too low, the length of therapy and the duration of bacterial exposure to long-acting agents compared to drugs with short half-lives. Therefore, there are three main ways to control selection and spread of resistant strains: by (i) reducing the amount of antibacterials used; (ii) using optimal dosages (avoiding underdosing) and treatments of short duration; and (iii) reducing the risk of transmission among young children attending daycare centres or kindergartens. In order to help physicians reduce the number of unnecessary prescriptions, it is important to develop rapid tests to recognise the bacterial origin of a febrile illness and even more important to detect resistance to antibacterials. However, apart from rapid diagnostic tests for streptococcal pharyngitis, those tests are not currently available. As a consequence, currently, the debate around narrow versus broad spectrum antibacterials remains a false debate. Physicians should use broad spectrum agents in many instances of upper or lower respiratory tract infection, taking into consideration the probable pathogens and the risk of (multi)resistance to antibacterials. Once rapid diagnostic are available in community practice, allowing a precise diagnosis of the offending agent and its susceptibility profile, physicians will be able to add to their current criteria the selective potential for resistance of the antibacterials that appear to be active in vitro.

Pneumococcal vaccination of children

Streptococcus pneumoniae is the most frequent cause of invasive bacterial infection in children younger than 2 years of age, reaching a peak incidence at 6 to 12 months of age. Pneumococci also cause many cases of pneumonia, sinusitis, and otitis media. Incidence rates of invasive infection in children with sickle cell disease, acquired or congenital splenectomy, or human immunodeficiency virus infection are 20- to 100-fold higher than are those of healthy children during the first 5 years of life. Other healthy children, such as those of American Indian, Native Alaskan, or African American descent, also have high rates of invasive infection, and those children enrolled in out-of-home care may have modestly increased risks. Pneumococcal polysaccharide polyvalent vaccines have been available for more than 2 decades but are limited in their usefulness for children because of their inability to induce protective antibody responses in children younger than 2 years of age and lack of immunologic memory. In contrast, pneumococcal protein conjugate vaccines induce presumptive protective responses in infants younger than 6 months, and immunologic memory further enhances responses after booster doses are given. Currently, a single heptavalent pneumococcal protein conjugate vaccine is licensed for use in the United States and is recommended for routine administration to all children, beginning at 2 months of age. It also is recommended for children between 24 and 59 months of age who are at high risk of acquiring invasive disease.

Household transmission of Streptococcus pneumoniae among siblings with acute otitis media

Nasopharyngeal transmission of Streptococcus pneumoniae was evaluated among 23 siblings with acute otitis media (AOM). Restriction fragment length polymorphism revealed that the nasopharyngeal strains were identical between siblings in 12 of 13 clusters of AOM experienced in 11 families. This study demonstrated person-to-person transmission of S. pneumoniae, especially drug-resistant strains, among siblings with AOM.

Cost burden of viral respiratory infections: issues for formulary decision makers

Viral respiratory infections (VRIs) are a common malady associated with considerable costs in terms of decreased productivity and time lost from work or school, visits to health-care providers, and the amount of drugs prescribed. Both total respiratory illness and rhinovirus infection peak during the fall and spring seasons, although the average percentage of office visits by patients with a rhinovirus infection is moderately high throughout the year. Most common cold remedies are relatively ineffective and may produce side effects that contribute to increased health-care costs. Antibiotic therapy is widely overused and misused despite evidence that antibiotics fail to treat the cause of VRI or prevent secondary bacterial infections. Increasing use of antibiotics has a significant impact on health-care costs and the emergence of antimicrobial resistance. Reasons for overprescribing antibiotics are varied, but they often involve physician and patient attitudes and expectations. Although treatment of VRIs poses challenges for effective formulary management, several steps can be taken to facilitate the introduction of antiviral agents, including patient and provider education, the development of rapid diagnostic tests, and medical-economics studies to determine the true cost of antiviral therapy.

Antibiotic use and upper respiratory infections: a survey of knowledge, attitudes, and experience in Wisconsin and Minnesota

BACKGROUND

Public attitudes and expectations contribute to inappropriate antibiotic prescribing and antibiotic resistance. This study assessed knowledge, attitudes, and experiences regarding antibiotic use for respiratory infection or illness.

METHODS

Random-digit-dialing telephone surveys of adults and parents of children <5 years old were conducted in Wisconsin and Minnesota during 1999.

RESULTS

The survey was completed by 405 adults and 275 parents of children <5 years old. The median age was 32 years for parents and 50 years for adults. Seven percent of parents and 17% of adults believed that antibiotics are never or almost never necessary for bronchitis. More than 70% in each group believed that antibiotics are needed for green or yellow nasal drainage, and nearly half of respondents believed that they knew whether an antibiotic was needed before seeing a physician. Exposure to multiple information sources on antibiotic resistance in the past 6 months was independently associated with a knowledge score greater than or equal to the median for nine questions.

CONCLUSIONS

The general public has misconceptions regarding indications for antibiotic use, and this may contribute to inappropriate prescribing. Providing multiple and varied antibiotic-related informational messages may increase knowledge of appropriate antibiotic prescribing and decrease patient demand for antibiotics.

Effect of beta lactam antibiotic use in children on pneumococcal resistance to penicillin: prospective cohort study

OBJECTIVE

To examine the relation between use of antibiotics in a cohort of preschool children and nasal carriage of resistant strains of pneumococcus.

DESIGN AND PARTICIPANTS

Prospective cohort study over two years of 461 children aged under 4 years living in Canberra, Australia.

MAIN OUTCOME MEASURES

Use of drugs, respiratory symptoms, and visits to doctors were documented in a daily diary by parents of the children during 25 months of observation. Isolates of pneumococci, which were cultured from nasal swabs collected approximately six monthly, were tested for antibiotic resistance.

RESULTS

From the four swab collections 631 positive pneumococcal isolates from 461 children were found, of which 13.6% were resistant to penicillin. Presence of penicillin resistant pneumococci was significantly associated with children's use of a beta lactam antibiotic in the two months before each swab collection (odds ratio 2.03 (95% confidence interval 1.15 to 3.56, P=0.01)). The odds ratio of the association remained >1 (though did not reach significance at the 0.05 level) for use in the six months before swab collection. The association was seen in children who received only penicillin or only cephalosporin antibiotics in that period. The odds ratio was 4.67 (1.29 to 17.09, P=0.02) in children who had received both types of beta lactam in the two months before their nasal swab. The modelled odds of carrying penicillin resistant pneumococcus was 4% higher for each additional day of use of beta lactam antibiotics in the six months before swab collection.

CONCLUSIONS

Reduction in beta lactam use could quickly reduce the carriage rates of penicillin resistant pneumococci in early childhood. In view of the propensity of these organisms to be spread among children in the community, the prevalence of penicillin resistant organisms may fall as a consequence.

Geographic, demographic, and seasonal differences in penicillin-resistant Streptococcus pneumoniae in Baltimore

We examined the epidemiology of invasive penicillin-resistant Streptococcus pneumoniae (PRSP) infections among residents of the Baltimore metropolitan area from 1995 through 1997. During this period, the proportion PRSP cases increased 42%, from 5.7% to 8.1% of cases. PRSP rates were highest among persons aged <5 and > or =65 years, black patients, and urban dwellers. However, the proportion of PRSP cases was higher among white persons (10%) than it was among black persons (5%) and among residents of suburban counties (10%) versus urban counties (6%). PRSP cases were more common in November-April (8%) than they were in May-October (5%), particularly for persons aged > or =65 years (10% vs. 1%). By use of logistic regression, white race, suburban residence, and winter respiratory season were found to be independent predictors of infection with PRSP. The incidence of PRSP is increasing in Baltimore, and the seasonality of PRSP suggests that recent antibiotic use, which is more common in winter months, may rapidly affect the prevalence of resistant pneumococcal infections.

Carriage of penicillin-resistant Streptococcus pneumoniae by children in day-care centers during an intervention program in Malmo, Sweden

BACKGROUND

An increasing incidence of penicillin-resistant Streptococcus pneumoniae (PRP) was detected in Malmo in 1994.

OBJECTIVE

To evaluate clonality and factors facilitating the spread of PRP among children in day-care centers (DCCs).

METHODS

We used phenotypic and DNA-fingerprinting methods in conjunction with epidemiologic data from the South Swedish Pneumococcal Intervention Project's investigation of 63 DCCs during a 3-year period (1995 to 1997) in the Malmo region.

RESULTS

A questionnaire about building and hygiene standards disclosed no statistically significant risk factor for carriage of pneumococci. However, age younger than the mean age at the DCC or in the child group was positively associated with carriage. Contrary to expectations no association with the number of children, either at the DCC or in the individual groups, was found. Of 2912 investigated children 1224 (42%) were carriers of S. pneumoniae, and 373 (12.8%) were PRP carriers (MIC > or = 0.1 microg/ml). Among isolates with MIC > or = 0.5 microg/ml 9 serogroups and 30 genetic types were found. Two clones in serogroups 9 (33%) and 19 (24%) were dominant in most municipality districts, and dominance was sustained during the whole study period. The previously internationally recognized serotype 9V clone seemed to be very stable, with a single DNA type and resistance pattern during the study period. In contrast the serogroup 19 isolates and other serogroups had diverse DNA types and resistance patterns, supporting the hypothesis that DCCs have a unique microenvironment facilitating the recombination of penicillin-binding protein genes among streptococci. In five DCCs we found PRP isolates with two different serogroups but an identical genetic type, indicating that serotype shift may be a common phenomenon in DCCs.

CONCLUSION

Multivariate logistic regression of risk factors disclosed that young age of the children in the child groups was a significant risk factor for carriage of S. pneumoniae.

Restricted use of antibiotic prophylaxis for recurrent acute otitis media in the era of penicillin non-susceptible Streptococcus pneumoniae

OBJECTIVE/INTERVENTION: To compare the annual rates of acute otitis media (AOM) episodes, antibiotic days, and ventilating tube insertion during the first 3 years of life before and after a practice change to restrict use of antibiotic chemoprophylaxis for recurrent AOM.

METHODS SETTING

The sole pediatric private practice in a rural Kentucky community.

PATIENTS

Population-based sample of all children born consecutively in two different 13 month intervals. Cohort 1 (n=251) was born before and Cohort 2 (n=274) was born after restricted use of chemoprophylaxis and documented emergence of widespread penicillin non-susceptible Streptococcus pneumoniae (PNSP).

DESIGN

Retrospective case cohort comparison.

MAIN OUTCOME MEASURES

Suppurative AOM diagnosed by validated experienced otoscopists using stringent tympanic membrane criteria.

RESULTS

Children were mostly white with the majority (50-65%) enrolled in daycare during each year. The first episode of AOM was experienced by 6 and 12 months of age in 64 and 86%, respectively. Rates of children with recurrent AOM in Cohorts 1 and 2 were 28 and 31% in Year 1, 17 and 23% in Year 2, and 7 and 10% in Year 3, respectively. Rates of new onset AOM and persistent AOM episodes were similar between cohorts in the first 2 years. Number of days of antibiotic prophylaxis were reduced from 11.2 to 3.4 days in Year 1, from 11.9 to 2.6 days in Year 2, and from 6.9 to 0.7 days in Year 3, respectively (P<0.0001 for each year). Total antibiotic days for Years 1, 2 and 3 were reduced commensurately with prophylactic days from 61.7 to 55.5 days (nonsignificant), from 56.3 to 45.8 days (P=0.047), and from 38.7 to 25.7 days (P<0.0001), respectively. For each year a non-significant trend for increased ventilating tube placement from Cohort 1 to Cohort 2, respectively, was observed, 2 versus 2.2%, 4 versus 5.8%, and 0.8 versus 2.6%. Daycare attendance and white race were consistently significant risk factors for AOM and recurrent AOM.

CONCLUSIONS

In the era of PNSP, restricted use of antibiotic chemoprophylaxis for recurrent AOM was not associated with significantly increased rates of new onset AOM episodes or tube placement in the first 24 months of life. Total antibiotic days were also significantly reduced in Cohort 2 during Years 2 and 3.

High rates of multiple antibiotic resistance in Streptococcus pneumoniae from healthy children living in isolated rural communities: association with cephalosporin use and intrafamilial transmission

OBJECTIVE

Streptococcus pneumoniae is one of the most clinically significant pathogens with emerging antibiotic resistance. We performed a surveillance study in isolated rural populations of healthy children to estimate the prevalence of pneumococcal resistance and to contrast factors that predict pneumococcal carriage with those that specifically predict resistant pneumococcal carriage.

METHODS

The study was conducted in 1998 in 2 rural communities in Utah. Families were recruited directly for participation through community canvassing. Surveillance nasopharyngeal cultures were obtained from children who were younger than 8 years. Antibiotic usage and information on other potential risk factors were obtained from questionnaires and local pharmacy records. Resistance was determined by testing isolates for susceptibility to penicillin, cefaclor, trimethoprim-sulfamethoxazole, erythromycin, ceftriaxone, and trovafloxacin. Selected resistant isolates were characterized further by serotyping, pulsed field gel electrophoresis, and Southern blot with DNA probes specific for the pneumococcal lytA gene and for antibiotic resistance genes.

RESULTS

In April 1998, surveillance nasopharyngeal cultures were obtained from 368 children aged </=8 years in community A and 369 children in community B. The number of antibiotic courses per child within 1 year before culture was higher in community B than A (mean: 2.2 vs 1.7). Conversely, oral cephalosporins were more frequently used in community A than B (community A: 22% received cephalosporins within 4 months; community B: 12%). Colonization with S pneumoniae was detected in 24% of children in community A and 14% in community B; 36% of isolates from community A and 28% of isolates from community B were resistant or intermediately susceptible to at least 1 antibiotic tested. Reduced susceptibility was most common to trimethoprim-sulfamethoxazole and cefaclor (28% and 26%, respectively). Pneumococcal carriage (susceptible or resistant) was independently associated with age <5 years (odds ratio [OR]: 2.2), child care exposure (OR: 2.4), presence of a sibling with a positive culture (OR: 3.3), and residence in community A (OR: 1.7). Among carriers, age <2 years (OR: 2.6), use of cephalosporins within the preceding 4 months (OR: 2.7), and having a sibling colonized with resistant S pneumoniae (OR: 5.5) were independent predictors of reduced susceptibility or resistance. Each pair of resistant isolates from siblings was indistinguishable by pulsed field gel electrophoresis and other molecular typing techniques. Several pneumococcal isolates from these isolated rural areas had the molecular characteristics of international clones of multiple-drug-resistant pneumococci that have been associated with worldwide spread.

CONCLUSIONS

Young age and intrafamilial transmission were important risk factors for carriage of both susceptible and resistant S pneumoniae. In contrast, previous cephalosporin use was linked specifically to resistant pneumococcal carriage, which suggests that modifications in antibiotic usage patterns may have salutary effects on antimicrobial resistance. These results extend previous observations in large cities regarding the penetration of multiple-drug-resistant clones of pneumococci into community populations.

Effect of a conjugate pneumococcal vaccine on the occurrence of respiratory infections and antibiotic use in day-care center attendees

BACKGROUND

Incidence and severity of respiratory infections are increased in day-care center attendees. Streptococcus pneumoniae is an important contributor to these infections.

OBJECTIVE

To examine whether the use of a pneumococcal conjugate vaccine could reduce the occurrence of respiratory infections and the ensuing antibiotic drug use in the day care.

METHOD

In this double blind, randomized, controlled study performed in 8 day-care centers located in Beer-Sheva, Israel, 264 toddlers ages 12 to 35 months at enrollment were randomized to receive either a 9-valent conjugate pneumococcal vaccine (conjugated to CRM197) or a control vaccine [conjugate meningococcus C vaccine (conjugated to CRM197)] and were followed for an average of 22 months. The main outcome measures were respiratory morbidity and antibiotic use.

RESULTS

An overall reduction of 7% in child months with > or = 1 reported illness episodes was observed among vaccinees (P = 0.008), and 85% of all episodes were related to the respiratory tract. Reductions of 15, 16 and 17% were observed in upper respiratory infections, lower respiratory problems and otitis media, respectively. An overall reduction of 17% in antibiotic days was observed [10% for upper respiratory infections, 20% for otitis and 47% for lower respiratory problems (P < or = 0.005 for each entity)]. The reduction in episodes and antibiotic use was greater for those <36 months of age than for the older children.

CONCLUSION

The reduction of respiratory problems, including those not traditionally considered of pneumococcal origin and the ensuing lowered antibiotic use in day-care center attendees by pneumococcal conjugate vaccination suggest a broader benefit from the vaccine than preventing invasive disease only.

Antimicrobial drug use and resistance among respiratory pathogens in the community

There is substantial evidence that the overuse of antibiotics is a major cause for the emergence of resistance in respiratory pathogens in the community. However, it is also recognized that the mechanisms of resistance, the cost of resistance to the fitness of the organism, and the ability of the resistant strain to disseminate are all important contributors to this problem. Therefore, when developing strategies to control and/or prevent the emergence of resistance, health care professionals must take each of these factors into consideration. As we enter a new era in the use of fluoroquinolones for the treatment of respiratory tract infections, we have an opportunity to apply such lessons learned in the past to minimize or prevent the development of resistance to this class of antimicrobial drugs in the future.

Development and spread of bacterial resistance to antimicrobial agents: an overview

Resistance to antimicrobial agents is emerging in a wide variety of nosocomial and community-acquired pathogens. The emergence and spread of multiply resistant organisms represent the convergence of a variety of factors that include mutations in common resistance genes that extend their spectrum of activity, the exchange of genetic information among microorganisms, the evolution of selective pressures in hospitals and communities that facilitate the development and spread of resistant organisms, the proliferation and spread of multiply resistant clones of bacteria, and the inability of some laboratory testing methods to detect emerging resistance phenotypes. Twenty years ago, bacteria that were resistant to antimicrobial agents were easy to detect in the laboratory because the concentration of drug required to inhibit their growth was usually quite high and distinctly different from that of susceptible strains. Newer mechanisms of resistance, however, often result in much more subtle shifts in bacterial population distributions. Perhaps the most difficult phenotypes to detect, as shown in several proficiency testing surveys, are decreased susceptibility to beta-lactams in pneumococci and decreased susceptibility to vancomycin in staphylococci. In summary, emerging resistance has required adaptations and modifications of laboratory diagnostic techniques, empiric anti-infective therapy for such diseases as bacterial meningitis, and infection control measures in health care facilities of all kinds. Judicious use is imperative if we are to preserve our arsenal of antimicrobial agents into the next decade.

Antimicrobial use and the emergence of antimicrobial resistance with Streptococcus pneumoniae in the United States

The rapid emergence of resistance to antimicrobial agents by Streptococcus pneumoniae in the United States has been influenced by various factors, including the clonal nature of most resistant strains and the fact that organisms with a multiresistant phenotype have become stably endemic. The ease with which transmission occurs and the fact that humans, especially children, are often colonized asymptomatically in the upper respiratory tract have contributed to the problem. Clearly, the most important factor in the emergence of antimicrobial resistance with S. pneumoniae, however, is the selective pressure of antimicrobial agents. Potency, defined as a product of both antibacterial effect and drug delivery, is a key factor. Generally speaking, the more potent an antimicrobial agent, the less likely it is to select for resistance. This is germane to comparisons of oral agents within specific antimicrobial classes (e.g., beta-lactams, macrolides, and fluoroquinolones). Within each class, potencies differ. In view of the existence of stably endemic multidrug-resistant S. pneumoniae, given comparable cost, side-effect profile, palatability, convenience of dosing, and accessibility, use of the most potent agent(s) within a particular class is advocated.

Pneumococcal carriage in children in The Netherlands: a molecular epidemiological study

In 1999, Engelen and coworkers investigated colonization in Amsterdam among 259 children attending 16 day-care centers (DCCs) and among 276 children who did not attend day-care centers (NDCCs). A 1.6- to 3.4-fold increased risk for nasopharyngeal colonization was observed in children attending DCCs compared with NDCC children, while no difference in antibiotic resistance was found between groups. The serotype and genotype distributions of 305 nasopharyngeal Streptococcus pneumoniae isolates of the latter study were investigated. The predominant serotypes in both the DCC and the NDCC groups included 19F (19 and 18%, respectively), 6B (14 and 16%, respectively), 6A (13 and 7%, respectively), 23F (9 and 7%, respectively), and 9V (7 and 7%, respectively). The theoretical vaccine coverage of the 7-valent conjugate vaccine was 59% for the DCC children and 56% for the NDCC group. Genetic analysis of the pneumococcal isolates revealed 75% clustering among pneumococci isolated from DCC attendees versus 50% among the NDCC children. The average pneumococcal cluster size in the DCC group was 3.8 and 4.6 isolates for two respective sample dates (range, 2 to 13 isolates per cluster), while the average cluster size for the NDCC group was 3.0 (range, 2 to 6 isolates per cluster). Similar to observations made in other countries, these results indicate a higher risk for horizontal spread of pneumococci in Dutch DCCs than in the general population. This study emphasizes the importance of molecular epidemiological monitoring before, during, and after implementation of pneumococcal conjugate vaccination in national vaccination programs for children.

A community intervention trial to promote judicious antibiotic use and reduce penicillin-resistant Streptococcus pneumoniae carriage in children

OBJECTIVE

Inappropriate use of antibiotics is common in primary care, and effective interventions are needed to promote judicious antibiotic use and reduce antibiotic resistance. The objective of this study was to assess the impact of parent and clinician education on pediatric antibiotic prescribing and carriage of penicillin-nonsusceptible Streptococcus pneumoniae in child care facilities.

METHODS

A nonrandomized, controlled, community intervention trial was conducted in northern Wisconsin Clinicians. Clinic staff received educational materials and small-group presentations; materials were distributed to parents through clinics, child care facilities, and community organizations. Prescribing data were analyzed for 151 clinicians who provided primary pediatric care; nasopharyngeal carriage of penicillin-nonsusceptible S pneumoniae was assessed for 664 children in the baseline period (January-June 1997) and for 472 children in the postintervention period (January-June 1998).

RESULTS

The median number of solid antibiotic prescriptions per clinician declined 19% in the intervention region and 8% in the control region. The median number of liquid antibiotic prescriptions per clinician declined 11% in the intervention region, compared with an increase of 12% in the control region. Retail antibiotic sales declined in the intervention region but not in the control region. Among participating children in child care facilities, there were no significant differences in antibiotic use or penicillin-nonsusceptible S pneumoniae colonization between the intervention and control regions.

CONCLUSIONS

A multifaceted educational program for clinicians and parents led to community-wide reductions in antibiotic prescribing, but in child care facilities, there was no apparent impact on judicious antibiotic use or colonization with drug-resistant S pneumoniae. Longer follow-up time or greater reductions in antibiotic use may be required to identify changes in the pneumococcal susceptibility.

Antibiotic-resistant pneumococci carried by young children do not appear to disseminate to adult members of a closed community

Although antibiotic-resistant pneumococci have been frequently detected among day care center (DCC) attendees, the transmission of these organisms to other members of the community has not been adequately studied. Nasopharyngeal cultures were obtained from 152 children and 244 adult members of a closed community (a kibbutz) in Israel. Serotyping, antibiogram, and pulsed-field gel electrophoresis were performed to determine the relatedness of isolated pneumococci. Twenty (30%) of the 66 isolates from children showed decreased susceptibility to penicillin and 9 isolates (14%) were resistant to > or =3 drugs. Of the 16 isolates from adults, 5 (31%) were intermediately resistant to trimethoprim-sulfamethoxazole. Resistant strains carried by DCC attendees were not isolated either from their parents or from other adult members of the community. Despite the high degree of interpersonal contact occurring in a closed community, resistant pneumococcal strains carried by DCC attendees do not appear to be easily transmitted to the adult population, which suggests the existence of an immunological barrier.

Acute otitis media in Brazilian children: analysis of microbiology and antimicrobial susceptibility

Between 1990 and 1995, a total of 300 children, ages 2 months to 5 years, received diagnoses of acute otitis media (AOM) in a hospital emergency room in São Paulo, Brazil, and were recruited for this study. The investigation was undertaken, first, to identify microorganisms and antimicrobial susceptibilities of pathogens from AOM in Brazilian children; next, to ascertain, by comparison, whether the isolates of Streptococcus pneumoniae have the same serotypes as those included in the new conjugated heptavalent pneumococcal vaccine; and last, to determine whether additional and/or different serotypes are needed in the vaccine to ensure an immunogenic response against pneumococcal pathogens for the indigenous children in this study. Microorganisms were isolated from ear fluid of 192 patients (64%). The 5 most prevalent pathogens were S pneumoniae (48 isolates; 16%), Haemophilus influenzae (21 isolates; 7%), Moraxella catarhalis (15 isolates; 5%), Pseudomonas aeruginosa (6 isolates; 2%), and Staphylococcus aureus (3 isolates; 1%). These 5 represented 93 of the 192 total isolates. Resistance to antibiotics was found in the 3 primary pathogens. No high-level resistance of S pneumoniae to penicillin was found; instead, there was high-level resistance to trimethoprim-sulfamethoxazole. Ten serotypes of S pneumoniae were isolated: 6B, 9V, 11A, 16, 18C, 19A, 19F, 23A, 23B, and 23F. Only 5 of the 10 serotypes isolated were included in the conjugated heptavalent pneumococcal vaccine. Therefore, the other 5 serotypes (24 of 48 strains) should be considered in selecting antigens for the new vaccine.

Bacterial infection in chronic obstructive pulmonary disease in 2000: a state-of-the-art review

Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States. The precise role of bacterial infection in the course and pathogenesis of COPD has been a source of controversy for decades. Chronic bacterial colonization of the lower airways contributes to airway inflammation; more research is needed to test the hypothesis that this bacterial colonization accelerates the progressive decline in lung function seen in COPD (the vicious circle hypothesis). The course of COPD is characterized by intermittent exacerbations of the disease. Studies of samples obtained by bronchoscopy with the protected specimen brush, analysis of the human immune response with appropriate immunoassays, and antibiotic trials reveal that approximately half of exacerbations are caused by bacteria. Nontypeable Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pneumoniae are the most common causes of exacerbations, while Chlamydia pneumoniae causes a small proportion. The role of Haemophilus parainfluenzae and gram-negative bacilli remains to be established. Recent progress in studies of the molecular mechanisms of pathogenesis of infection in the human respiratory tract and in vaccine development guided by such studies promises to lead to novel ways to treat and prevent bacterial infections in COPD.

Novel penicillin-, cephalosporin-, and macrolide-resistant clones of Streptococcus pneumoniae serotypes 23F and 19F in Taiwan which differ from international epidemic clones

A cluster (14 of 18) of Streptococcus pneumoniae serotype 23F isolates that were resistant to penicillin (PEN), cephalosporin, and macrolide was found in one day care center in Kaohsiung, Taiwan. We analyzed the 18 isolates by pulsed field gel electrophoresis (PFGE). All but one serotype 23F isolate demonstrated identical PFGE patterns, which were different from the established pattern of the internationally spread Spanish 23F clone. The three strains of serotype 19F also showed a uniform pattern. These data strongly suggest that two novel clones of PEN-, cephalosporin-, and macrolide-resistant S. pneumoniae serotypes 23F and 19F are present in Taiwan.

A prospective study of antibiotic use and associated infections in young children

This study examines antibiotic usage and associated infections in infants and young children in Iowa. Longitudinal data were collected using a cohort recruited at birth from eight hospitals in eastern Iowa. Parents of recruited children were mailed questionnaires at 6 weeks, and 3, 6, 9, 12, 16, and 20 months of age. The cumulative incidence of antibiotic use and associated infections was determined using Kaplan-Meier survival analysis. There were data on 1,368 children. Antibiotic use was common in our cohort and increased with age. Beginning at age 3 months, approximately 50% of the cohort was exposed to an antibiotic during each reporting period. Otitis media was the most common indication and was responsible for 67.3% of antibiotic use. Children were most frequently treated with amoxicillin, followed by the cephalosporins and sulphonamides. By 12 and 20 months of age 79.0% and 92.5% of the children, respectively, had been treated with at least one course of antibiotics. Children received antibiotics for a median of 43 days by 20 months of age. Males were more likely to experience any antibiotic exposure than females (hazard ratio = 1.18) and showed a trend for more days of use (P = 0.052). There was a small but significant variation in antibiotic usage in the different recruitment communities (P = 0.02).

The effect of a community intervention trial on parental knowledge and awareness of antibiotic resistance and appropriate antibiotic use in children

BACKGROUND

Overuse of antibiotics for children's upper respiratory infections is widespread and contributes to the emergence of antibiotic-resistant bacteria.

OBJECTIVE

To assess changes in knowledge and awareness regarding antibiotic resistance and appropriate antibiotic use after community-wide educational interventions to reduce inappropriate antibiotic use.

DESIGN

Baseline survey conducted during June through July 1997 and postintervention survey of baseline participants during June through August 1998.

SETTING

Communities in northern Wisconsin.

PARTICIPANTS

Parents of 729 randomly selected children <4 years of age were called until 215 in each of the intervention and control areas were reached. Of the 430 baseline participants, 365 (85%) participated in the postintervention survey.

INTERVENTION

Parent-oriented activities included distribution of materials and presentations. Physician-oriented activities included formal presentations and small group meetings.

OUTCOME MEASURE

Change in awareness about antibiotic resistance and knowledge about antibiotic indications.

RESULTS

A higher proportion of parents in the intervention area (53%) were exposed to 2 or more local educational messages, compared with the control area (23%). From the baseline to the postintervention survey, the percentage of parents with a high degree of antibiotic resistance awareness increased more in the intervention area (58% to 73%) than in the control area (60% to 65%). In the intervention area, there was also a larger increase in knowledge regarding appropriate indications for antibiotic use, compared with the control area. The proportion of parents who expected an antibiotic for their child and did not receive one declined in the intervention area (14% to 9%), while it increased in the control area (7% to 10%). In addition, the percentage of parents in the intervention area who brought their child to another physician because they did not receive an antibiotic decreased (5% to 2%), while it increased in the control area (2% to 4%).

CONCLUSION

Parental knowledge and awareness about antibiotic indications and antibiotic resistance can be changed with educational interventions directed at parents and clinicians.

Oral antibiotic use without consulting a physician: a survey of ED patients

The purpose of our study was to determine the extent to which patients use antibiotics without consulting a physician and to examine patient characteristics associated with such oral antibiotic misuse. The study design was a prospective survey. The setting was a suburban, community, emergency department (ED). The participants were a convenience sample of oriented, ED patients who were enrolled during an 8-week period. Subjects provided written answers to standardized questions regarding their use of oral antibiotics over the 12 months preceding their ED visit. Categorical and continuous data were analyzed by chi-square and t-tests respectively. All test were 2-tailed with alpha set at 0.05. One thousand three hundred sixty three subjects were enrolled; 80% were White, 54% were female, 58% had attended college, 85% had a private physician, and 88% had health insurance. The mean age was 45 +/- 19 years. 43% of patients had used oral antibiotics within the past year. Twenty-two percent of patients indicated that their physicians routinely prescribed antibiotics for their cold symptoms. Seventeen percent of patients had taken "left-over" antibiotics without consulting their physician, most commonly for a cough (11%) or sore throat (42%), and much less frequently for urinary tract infection symptoms (0.7%). Women (19% versus 15% men; P =.04) and patients who attended college (19% versus 14% no college; P =.01) were more likely to have taken "left-over" antibiotics. A significant percentage of our ED patients had taken oral antibiotics without consulting a physician for symptoms frequently caused by viruses. Further study is warranted to examine whether local patterns of outpatient self-prescribing affect community oral antibiotic resistance.

Molecular epidemiology of penicillin-nonsusceptible Streptococcus pneumoniae among children in Greece

A total of 145 penicillin-nonsusceptible Streptococcus pneumoniae strains were isolated from young carriers in Greece and analyzed by antibiotic susceptibility testing, serotyping, restriction fragment end labeling (RFEL), and penicillin-binding protein (PBP) genotyping. The serotypes 23A and 23F (54%), 19A and 19F (25%), 9V (5%), 15A, 15B, and 15C (4%), 6A and 6B (4%), and 21 (4%) were most prevalent in this collection. Fifty-three distinct RFEL types were identified. Sixteen different RFEL clusters, harboring 2 to 32 strains each, accounted for 82% of all strains. Eight of these genetic clusters representing 60% of the strains were previously identified in other countries. A predominant lineage of 66 strains (46%) harboring five RFEL types and the serotypes 19F and 23F was closely related to the pandemic clone Spain(23F)-1 (genetic relatedness of > or =85%). Another lineage, representing 11 strains, showed close genetic relatedness to the pandemic clone France(9V)-3. Another lineage of 8 serotype 21 strains was Greece specific since the RFEL types were not observed in an international collection of 193 genotypes from 16 different countries. Characterization of the PBP genes pbp1a, pbp2b, and pbp2x revealed 20 distinct PBP genotypes of which PBP type 1-1-1, initially observed in the pandemic clones 23F and 9V, was predominantly present in 11 RFEL types in this Greek collection of penicillin-nonsusceptible strains (55%). Sixteen PBP types covering 52 strains (36%) were Greece specific. This study underlines the strong contribution of penicillin-resistant international clones to the prevalence and spread of penicillin-nonsusceptible pneumococci among young children in Greece.

treatment and prevention of otitis media

OBJECTIVE

To review and summarize recent advances in the treatment and prevention of otitis media (OM).

DATA SOURCES

A MEDLINE search (1996-March 2000) was performed to identify relevant primary and review articles. References from these articles were also reviewed if deemed important.

STUDY SELECTION AND DATA EXTRACTION

English-language primary and review articles focusing on the treatment and prevention of acute otitis media (AOM) were included. Studies focusing exclusively on OM with effusion or serous OM and chronic suppurative OM were excluded. Information regarding prevention and drug therapy was reviewed, with an emphasis placed on advances made in the last two years.

DATA SYNTHESIS

Recently, an expert panel of the Centers for Disease Control and Prevention recommended use of only three of 16 systemic antibiotics approved by the Food and Drug Administration for treatment of AOM: amoxicillin, cefuroxime axetil, and ceftriaxone. Controversy exists over the importance of key selection factors used by the expert panel in determining which antibiotics to recommend in a two-step treatment algorithm, that is, in vitro data, pharmacodynamic profiles, and necessity for coverage of drug-resistant Streptococcus pneumoniae at all steps of empiric treatment. Additional antibiotic and patient selection factors useful for individualizing therapy include clinical efficacy, adverse effects, frequency and duration of administration, taste, cost, comorbid infections, and ramifications should bacterial resistance develop to the chosen antibiotic. Presumed or past patient/caregiver adherence (especially when antibiotic failure has occurred) is also paramount in selecting antibiotic therapy. A three-step treatment algorithm for refractory AOM that employs amoxicillin, trimethoprim/sulfamethoxazole (TMP/SMX), or high-dose amoxicillin/clavulanate (depending on the prior dose of and adherence to amoxicillin therapy), and ceftriaxone or tympanocentesis at steps 1, 2, and 3, respectively, appears rational and cost-effective. The recent upsurge in antimicrobial resistance is highlighted, and recommendations are presented for the treatment of AOM and prevention of recurrent otitis media (rAOM).

CONCLUSIONS

Amoxicillin remains the antibiotic of choice for initial empiric treatment of AOM, although the traditional dosage should be increased in patients at risk for drug-resistant S. pneumoniae. In cases refractory to high-dose amoxicillin, TMP/SMX should be prescribed if adherence to prior therapy seemed good or complete, or high-dose amoxicillin/clavulanate if adherence was incomplete or questionable. Ceftriaxone should be reserved as third-line treatment. The increasing prevalence of drug-resistant S. pneumoniae emphasizes the importance of alternative medical approaches for the prevention of OM, as well as judicious antibiotic use in established cases. Removal of modifiable risk factors should be first-line therapy for prevention of rAOM. We support the use of conjugate pneumococcal vaccine per guidelines for prevention of rAOM from the Advisory Committee on Immunization Practice of the Centers for Disease Control and Prevention, with consideration given to influenza vaccine for cases of rAOM that historically worsen during the flu season. Sulfisoxazole prophylaxis should be reserved for children who are immunocompromised, have concurrent disease states exacerbated by AOM, or meet the criteria of rAOM despite conjugate pneumococcal and influenza vaccination. Therapy should be intermittent, beginning at the first sign of an upper respiratory infection, and should continue for 10 days. The invasive nature and risks of anesthesia relegate myringotomy, tympanostomy tubes, and adenoidectomy to last-line therapies for rAOM.