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

Multidrug-resistant Pathogens: Mechanisms of Resistance and Epidemiology

Resistance to antimicrobial agents among bacteria and fungi is a persistent problem complicating the management of critically ill patients. To understand the issues involved in resistance in critical care, it is essential to understand the epidemiology and mechanisms of resistance. beta-lactam resistance in pneumococci, and penicillin and chloramphenicol resistance in Neisseria meningitidis, have complicated the management of meningitis. Vancomycin resistance in enterococci and methicillin resistance in Staphylococcus aureus have disseminated among hospitals, nursing homes and, in some cases, community patients. Glycopeptide resistance in S. aureus has recently been described in clinical isolates; the potential for spread of this resistance trait is concerning. Resistance to broad-spectrum cephalosporins is a persistent challenge in the management of infections caused by Pseudomonas areuginosa, and Enterobacter species, as well as other Enterobacteriaceae. Azole resistance in Candida species. has also complicated the treatment of nosocomial infections. Resistance to antimicrobial drugs is a persistent and emerging problem and presents major therapeutic challenges.

Antimicrobial use and colonization with erythromycin-resistant Streptococcus pneumoniae in Greece during the first 2 years of life

We evaluated nasopharyngeal colonization with erythromycin-resistant Streptococcus pneumoniae during the first 2 years of life in central and southern Greece. Of 2448 children studied from February 1997 to February 1999, 766 (31%) carried 781 pneumococcal isolates. Ninety-five (3.9%) of the children attended day care centers. Eighteen percent of the pneumococci were resistant to erythromycin (minimal inhibitory concentration 1 to >128 microg/mL), with 67.9% of them carrying the erm(B) gene and 29.2% mef(A) gene products. Four strains possessed neither the erm(B) nor the mef(A) gene. Multidrug resistance occurred in 97% and 40% of isolates carrying the erm(B) and mef(A) gene, respectively. An association was found between the erm(B) gene and serotypes 6B and 23F and between the mef(A) gene and serotypes 14 and 19F. A significant relationship existed between carriage of erythromycin-resistant pneumococci and use of macrolides or beta-lactams in the previous 3 months; the association was strongest when macrolide therapy was administered during the last month (odds ratio, 5.92; P=.0001). The findings indicate the necessity of a judicious use of both macrolides and beta-lactams in young children to reduce the colonization with erythromycin-resistant pneumococci and the subsequent spread of such strains to the community.

Antibiotic prescribing for patients with colds, upper respiratory tract infections, and bronchitis: A national study of hospital-based emergency departments

STUDY OBJECTIVE

Antibiotics are often used to treat viral upper respiratory tract infections, even though they are usually ineffective. However, frequent inappropriate antibiotic use contributes to the emergence of drug-resistant bacterial pathogens. This study used a national database to evaluate antibiotic use in treating upper respiratory tract infections in emergency departments.

METHODS

Data were obtained from the 1996 National Hospital Ambulatory Medical Care Survey. Antibiotic prescribing rates were examined for colds, upper respiratory tract infections, and acute bronchitis. Patients with comorbid conditions or secondary diagnoses, such as chronic obstructive pulmonary disease, pneumonia, sinusitis, and HIV, were excluded. Bivariate and multivariate analyses were used to assess predictors of antibiotic use.

RESULTS

Overall, there were an estimated 2.7 million ED visits for colds, upper respiratory tract infections, and bronchitis by children and adults in 1996. Antibiotics were prescribed for 24.2% (95% CI 18.9, 29.5) of patients with common colds and upper respiratory tract infections and for 42.2% (95% CI 35.2, 49.2) of patients with bronchitis. There were no significant associations between antibiotic use and patient race, sex, Hispanic ethnicity, geographic location, or source of payment. Antibiotics were prescribed less often by interns or residents than by staff or other physicians (odds ratio 0.43; 95% CI 0.19, 0.98), and patients younger than 18 years were less likely to receive antibiotics than adults (odds ratio 0.32; 95% CI 0.20, 0.52). Smokers were 4.3 (95% CI 2.2, 8.3) times more likely to receive antibiotics than nonsmokers.

CONCLUSION

Antibiotics are commonly prescribed for ED patients with upper respiratory tract infections even though they are usually ineffective in otherwise healthy adults. Efforts should be made to reduce inappropriate antibiotic use for the sake of containing costs, preventing side effects, and limiting the spread of antibiotic resistance.

Experimental study of the virulence of Streptococcus pneumoniae with reduced susceptibility to penicillin

Streptococcus pneumoniae is a major cause of morbidity and mortality in all age groups. In a few years, penicillin non-susceptible pneumococci (PNSP) have emerged worldwide as a new threat. In order to better understand the mechanisms behind the rapid expansion of these strains, the virulence of 10 clinical and two transformed PNSP strains were compared with the virulence of three fully susceptible strains in a mouse model of bacteremia and a rat model of acute otitis media. Serotype, antibiotic susceptibility, and to some extent also genetic profile and growth rate of the strains were investigated before inoculation. The animals were monitored for up to 7 days after challenge by clinical examinations/otomicroscopy and cultures from middle ears and blood. The results of the study demonstrated that the PNSP strains had a significantly reduced ability to persist at the infectious site, and to some extent also to induce infections, compared with fully susceptible strains. The reduction was most evident for strains isolated from sources other than blood. It is therefore possible that other factors than virulence factors are of importance for the ability of PNSP strains to expand.

Judicious use of antibiotics for common pediatric respiratory infections

BACKGROUND

Antibiotic resistance among common respiratory infection-producing bacteria such as Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis has become a major global public health problem. The use of antibiotics, whether or not medically justified for a particular illness, contributes to the development of resistant bacteria. To help to contain the proliferation of drug-resistant bacteria, members of the CDC and the American Academy of Pediatrics (AAP) recently published principles for the judicious use of antibiotics in common pediatric respiratory infections including the common cold, otitis media, sinusitis and tonsillopharyngitis. This article reviews the CDC/AAP principles for management of these illnesses and describes results of clinical practice studies in which efforts to improve the judicious use of antibiotics were undertaken.

CONCLUSIONS

The success of the CDC/AAP principles in containing the increase in antimicrobial resistance depends upon their being practiced. Results of clinical practice studies indicate that judicious use of antimicrobial therapy in pediatric respiratory infections can be realized through education and persistence. More widespread educational and behavior modification efforts are necessary to reduce unnecessary prescription of antibiotics and to curtail the still burgeoning problem of bacterial resistance.

Pacifier as a risk factor for acute otitis media: A randomized, controlled trial of parental counseling

OBJECTIVES

To evaluate the association between pacifier use and the increased occurrence of acute otitis media (AOM) in an intervention trial.

METHODS

Fourteen well-baby clinics were selected to participate in an open, controlled cohort study. These clinics were paired according to the number of children and the social classes of the parents they served. One clinic in each pair was randomly allocated for an intervention, while the other served as a control. The nurses at the intervention clinics were trained to instruct the parents of children <18 months old to limit pacifier use during their prescheduled visits to the clinic. The intervention consisted of a leaflet explaining the harmful effects of pacifier use and instructions to restrict its use. Two hundred seventy-two children were successfully recruited from the intervention clinics and 212 from the control clinics. The data about pacifier use and the occurrence of respiratory infections and AOM were collected similarly in both groups.

RESULTS

After the intervention, a 21% decrease was achieved in continuous pacifier use at the age of 7 to 18 months (P =.0001), and the occurrence of AOM per person-months at risk was 29% lower among children at the intervention clinics. The children who did not use a pacifier continuously in either of the clinics had 33% fewer AOM episodes than the children who did.

CONCLUSION

Pacifier use appeared to be a preventable risk factor for AOM in children. Its restriction to the moments when the child was falling asleep effectively prevented episodes of AOM.

Susceptibility of 1100 Streptococcus pneumoniae strains isolated in 1997 from seven Latin American and Caribbean countries. Laser Study Group

The antimicrobial susceptibility to beta-lactam and non-beta-lactam agents of 1100 isolates of Streptococcus pneumoniae recovered in 1997 from 16 centres in Argentina, Brazil, Chile, Mexico, Panama, Venezuela and West Indies was studied using E-test and disk diffusion methods. A total of 23.6% of isolates had raised penicillin MICs (16.7% intermediate and 6.9% resistant). The susceptibility of the other agents tested, from most active to least active, were, amoxycillin/clavulanate (99.5% susceptible); chloramphenicol (93.2%); cefotaxime (91.7%); erythromycin (87.1%); tetracycline (74.6%); trimethoprim/sulphamethoxazole (TMP-SMZ) (55.4%); and cefaclor (52.8%). The highest proportion of strains resistant to penicillin, chloramphenicol, erythromycin, tetracycline and TMP-SMZ was found in strains from Mexico while resistance to these agents was lowest in strains from the West Indies. Prevalence of penicillin resistance (including intermediate and resistant isolates) in each of the countries, from highest to lowest was, Mexico (40.8%); Chile (31.3%); Panama (23.0%); Venezuela (21.9%); Argentina (19.1%); Brazil (12.9%); and West Indies (7.1%). Based on current levels of antimicrobial resistance of S. pneumoniae in Latin American and Caribbean countries, continued surveillance efforts are necessary in order to guide clinical empiric treatment and provide for judicious use of antimicrobial agents.

American Academy of Pediatrics. Committee on Infectious Diseases. Technical report: prevention of pneumococcal infections, including the use of pneumococcal conjugate and polysaccharide vaccines and antibiotic prophylaxis

Pneumococcal infections are the most common invasive bacterial infections in children in the United States. The incidence of invasive pneumococcal infections peaks in children younger than 2 years, reaching rates of 228/100,000 in children 6 to 12 months old. Children with functional or anatomic asplenia (including sickle cell disease [SCD]) and children with human immunodeficiency virus infection have pneumococcal infection rates 20- to 100-fold higher than those of healthy children during the first 5 years of life. Others at high risk of pneumococcal infections include children with congenital immunodeficiency; chronic cardiopulmonary disease; children receiving immunosuppressive chemotherapy; children with immunosuppressive neoplastic diseases; children with chronic renal insufficiency, including nephrotic syndrome; children with diabetes; and children with cerebrospinal fluid leaks. Children of Native American (American Indian and Alaska Native) or African American descent also have higher rates of invasive pneumococcal disease. Outbreaks of pneumococcal infection have occurred with increased frequency in children attending out-of-home care. Among these children, nasopharyngeal colonization rates of 60% have been observed, along with pneumococci resistant to multiple antibiotics. The administration of antibiotics to children involved in outbreaks of pneumococcal disease has had an inconsistent effect on nasopharyngeal carriage. In contrast, continuous penicillin prophylaxis in children younger than 5 years with SCD has been successful in reducing rates of pneumococcal disease by 84%. Pneumococcal polysaccharide vaccines have been recommended since 1985 for children older than 2 years who are at high risk of invasive disease, but these vaccines were not recommended for younger children and infants because of poor antibody response before 2 years of age. In contrast, pneumococcal conjugate vaccines (Prevnar) induce proposed protective antibody responses (>.15 microg/mL) in >90% of infants after 3 doses given at 2, 4, and 6 months of age. After priming doses, significant booster responses (ie, immunologic memory) are apparent when additional doses are given at 12 to 15 months of age. In efficacy trials, infant immunization with Prevnar decreased invasive infections by >93% and consolidative pneumonia by 73%, and it was associated with a 7% decrease in otitis media and a 20% decrease in tympanostomy tube placement. Adverse events after the administration of Prevnar have been limited to areas of local swelling or erythema of 1 to 2 cm and some increase in the incidence of postimmunization fever when it is given with other childhood vaccines. Based on data in phase 3 efficacy and safety trials, the US Food and Drug Administration has provided an indication for the use of Prevnar in children younger than 24 months.

Impact of antimicrobial therapy on nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis in children with respiratory tract infections

We conducted a multicenter prospective study to document changes in nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis during antibiotic therapy. A cohort of 629 children with respiratory tract infections underwent nasopharyngeal sampling before and after antibiotic treatment. Susceptibility testing, serotyping, arbitrarily primed polymerase chain reaction, and pulsed-field gel electrophoresis were used to compare pretreatment and posttreatment strains of S. pneumoniae. A significant decrease in carriage of all 3 species (especially S. pneumoniae and B. catarrhalis) was recorded. The increase in the proportion of penicillin-resistant pneumococci (PRP; 66% vs. 44%) was due to the decreased carriage of penicillin-susceptible pneumococci (71 of 629 vs. 176 of 629). The risk of PRP carriage in a given child did not increase. None of the children was found to harbor genetically related strains with increased minimum inhibitory concentrations. Given the multiple resistance of PRP, beta-lactam antibiotic therapy also increased the incidence of macrolide-resistant strains, whereas macrolides selected both macrolide- and penicillin-resistant strains.

Pathogens resistant to antimicrobial agents. Epidemiology, molecular mechanisms, and clinical management

The emergence of resistance to antimicrobial agents continues to be a major problem in the nosocomial setting and now in nursing homes and the community as well. Bacteria use a variety of strategies to avoid the inhibitory effects of antibiotic agents and have evolved highly efficient means for the dissemination of resistance traits. Control of antibiotic-resistant pathogens provides a major challenge for both the medical community and society in general. To control the emergence of resistant pathogens, CDC and infection control guidelines must be adhered to, and antibiotics must be used more judiciously.

Nonsusceptible Streptococcus pneumoniae in children with chronic otitis media with effusion and recurrent otitis media undergoing ventilating tube placement

CONTEXT

Children with chronic otitis media are at risk for nonsusceptible Streptococcus pneumoniae (NSP) infection. If these children undergo ventilating tube placement, there is an opportunity to culture middle ear fluid and the nasopharynx to determine carriage of NSP.

OBJECTIVE

To determine the incidence of NSP carriage, NSP antibiotic susceptibility and risk factors for NSP carriage in children with chronic otitis media undergoing tube placement.

DESIGN AND SETTING

Prospective cohort study in an academic medical center with recruitment of patients from an otolaryngology private practice and clinic.

PATIENTS

Children < 18 years of age undergoing tube placement for chronic otitis media.

INTERVENTIONS

Myringotomy and tube placement, with culture of middle ear fluid and nasopharynx.

MAIN OUTCOME MEASURES

The incidence of NSP cultured from the middle ears and nasopharynx of recruited subjects with the use of the minimum inhibitory concentration break points for penicillin susceptibility recommended by the National Committee for Clinical Laboratory Standards.

RESULTS

S. pneumoniae was identified in at least 1 site from 23 of 300 study subjects (7.6%); of these 23, 12 case subjects (52.2%) harbored NSP. Of the risk factors assessed by preoperative questionnaire, only younger age was associated with NSP colonization (P < 0.0001). Of the six oral cephalosporins studied, cefpodoxime and cefuroxime showed good in vitro activity against S. pneumoniae isolates with intermediate penicillin resistance.

CONCLUSIONS

Children with chronic otitis media undergoing tube placement may carry NSP and provide a means of monitoring the incidence of NSP and antibiotic susceptibilities for children with ear infections in their communities. Younger age is a risk factor for NSP carriage in this population.

Antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic

BACKGROUND

To assist the Central African Republic (CAR) develop national guidelines for treating children with pneumonia, a survey was conducted to determine antimicrobial resistance rates of nasopharyngeal isolates of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI). Secondary purposes of the survey were to identify risk factors associated with carriage of a resistant isolate and to compare the survey methods of including only children with pneumonia vs. including all ill children.

METHODS

A cross-sectional survey of 371 ill children was conducted at 2 outpatient clinics in Bangui, CAR.

RESULTS

In all 272 SP isolates and 73 HI isolates were cultured. SP resistance rates to penicillin, trimethoprim-sulfamethoxazole (TMP-SMX), tetracycline and chloramphenicol were 8.8, 6.3, 42.3 and 9.2%, respectively. All penicillin-resistant SP isolates were intermediately resistant. HI resistance rates to ampicillin, TMP-SMX and chloramphenicol were 1.4, 12.3 and 0%, respectively. The most common SP serotypes/groups were 19, 14, 6 and 1; 49% of HI isolates were type b. History of antimicrobial use in the previous 7 days was the only factor associated with carriage of a resistant isolate. Resistance rates were similar among ill children regardless of whether they had pneumonia.

CONCLUSIONS

Resistance rates were low for antimicrobials recommended by the World Health Organization for children with pneumonia. We recommended TMP-SMX as the first line treatment for pneumonia in CAR because of its low cost, ease of dosing and activity against malaria.

Community-acquired pneumonia

Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide and has significant financial implications for health-care systems. The epidemiology and fundamental biology of the disease has evolved, reflecting the human immunodeficiency virus pandemic, increasing world travel, and, as always, poverty. The promise held out by molecular diagnostic technology has yet to deliver in this arena, and antibiotic resistance continues to drive the quest for new antimicrobial agents. The emergence of multidrug-resistant Streptococcus pneumoniae, the microorganism most often implicated as a cause of CAP, continues to threaten treatment options. The evolution of this organism, the persistently high mortality rate associated with CAP, and increasing health-care costs have prompted the publication of guidelines by various authorities that can be used to assist in the initial assessment of the patient and then guide empirical antimicrobial therapy. It is unclear whether these guidelines will have significant impact on cost and mortality, although the trend toward a rational and evidence-based approach to antimicrobial therapy must be a goal to aspire to.

Clinical significance of resistant organisms in otitis media

BACKGROUND

Otitis media is an important health care problem of childhood. The bacteriology of otitis media comprises three main pathogens: Streptococcus pneumoniae, nontypable Haemophilus influenzae and Moraxella catarrhalis. Although the prevalence of resistant strains varies geographically and temporally, antimicrobial resistance is widespread and increasing.

RESISTANCE TO ANTIBIOTIC DRUGS

Among the risk factors for development of resistance in otitis media are antimicrobial use, young age, day-care attendance and prior hospitalization. The increasing rate of resistance to antibiotic drugs is associated with a decreased rate of successful eradication of pathogens from middle ear fluid, which is associated with clinical failure. A bacteriologic cure rate of 80 to 85% is observed for S. pneumoniae and nontypable H. influenzae when serum concentrations exceed the MIC for 40 to 50% of dosing interval. Comparative trials indicate that some of the beta-lactams can achieve bacteriologic eradication in acute otitis media, although major differences in outcome exist among agents based on pathogen, beta-lactamase status and MIC values.

ANTIBIOTIC CHOICE

Overall the choice of antibiotics for treatment of otitis media should take into consideration their in vitro activity against the locally prevalent organisms, especially resistant organisms, and results obtained from studies in which bacteriologic outcome was used as the endpoint.

In vitro development of resistance of Streptococcus pneumoniae to beta-lactam antibiotics

In recent years, increasing numbers of Streptococcus pneumoniae strains displaying relative resistance to penicillin have been reported. Epidemiological studies have shown a correlation between aminopenicillin administration and resistance. We investigated the development of resistance in six strains (four sensitive and two intermediate-resistant to penicillin) by serial daily passages in subinhibitory concentrations of amoxicillin (AMX), amoxicillin + clavulanic acid (AMC), imipenem (IMP), cefixime (CFM), cefatrizine (CTZ), cefadroxil (CDX), and cefuroxime (CXM). MICs were determined by the macrodilution method in brain-heart broth for each daily passage. The number of daily passages needed to increase the MIC by a factor of 8 was achieved with AMX, AMC, and CFM for most of the strains after a mean of 24, 20, and 11 passages, respectively, and for one-third of the strains, with CDX, IMP, and CTZ after 11, 11, and 21 passages, respectively. Decreased susceptibility to breakpoints for intermediate-resistant S. pneumoniae populations was noted for all strains with CFM, AMX, and AMC after a mean of 10, 18, and 21 serial passages, respectively, and for four of five strains with IMP and CTZ after 12 and 13 passages. CTZ-, CDX-, and CXM-passaged variants had increased MIC values only for cephalosporins, while AMX-, AMC-, IMP-, and CFM-passaged variants exhibited increased MICs to all antibiotics tested. These in vitro data appear to be in agreement with epidemiological studies and warrant further exploration with respect to possible clinical implications.

Antibiotic susceptibility of Streptococcus pneumoniae isolates in Portugal. A multicenter study between 1989 and 1993

A total of 1,104 strains of Streptococcus pneumoniae were isolated from hospitalized patients (75.5%) and from colonization sites at the Public Health Institute (24.5%) during the last 4 years (1989-1993). Penicillin resistance (defined as MIC > or = 0.1 microgram/liter) was found to increase in time: 4.6% in 1989, 4.9% in 1990, 6.4% in 1991, 11.3% in 1992, and 17% in 1993. In 1992, 0.8% of the strains had penicillin MIC = 2 mg/liter. Increase in penicillin resistance was also evident among invasive strains [blood, cerebrospinal fluid (CSF), pleura]: 2/92 isolates from 1989-1992 (2.3%) were penicillin resistant as compared to 7/101 isolates from 1992 (6.9%). Multiresistance (resistance to three or more antibiotics) was 4.4% with penicillin, tetracycline, chloramphenicol being the predominant resistant phenotype at the end of 1992. In 1993, strains with resistance to penicillin plus chloramphenicol plus tetracycline increased further. Erythromycin resistance was usually associated with clindamycin resistance, but the majority of such strains remained susceptible to penicillin. Drift in the direction of increasing MIC values was also noted during this 3-year period among "susceptible" isolates: bacteria with MIC of 6-10 ng/ml representing the majority of isolates in 1990-1991 decreased and were replaced by cells with MIC of 20 ng/ml. The most frequent pneumococcal serotypes were 23, 19, 3, 6, 14, 9, and 8, with the frequency of type 9 increasing from 2.9% (in 1989) through 3.2% (1990) to 6.4% (1992). Among all antibiotic resistant strains, the prevalent serotypes were 23, 9, 14, and 6. The chromosomal backgrounds of resistant isolates tested by pulsed-field gel electrophoresis showed close resemblance to the background of the serotype 23F multiresistant clone first identified in Spain. The data suggest that the recent large increase in the frequency of penicillin-resistant pneumococci represents the import of this clone into Portugal during the early 1990s. The increased frequency of drug-resistant pneumococci highlights the importance of continued surveillance of these dangerous pathogens.

Effect of antimicrobial use and other risk factors on antimicrobial resistance in pneumococci

Penicillin-resistant and multi-resistant pneumococci have spread globally and reached high prevalence in many countries. Antimicrobial use is considered a major driving force for resistance, although the influence in the community has not been as clearly demonstrated. Other risk factors may be important, and only with a clear understanding of the risk factors can effective control measures be introduced. The main habitat of the pneumococcus is the nasopharynx of children. Carriage increases from birth and is maximal at pre-school age. Antimicrobial use in children is likely to have a significant influence on the susceptibility of pneumococci. Most studies looking for risk factors for resistance in pneumococci have identified antimicrobial use as a risk factor, especially the following aspects: ongoing, recent, repeated, frequent, and prophylactic antibiotic use. The effect of individual classes of antimicrobials has not been studied in detail but use of beta-lactam antibiotics and trimethoprim-sulpha has been associated with increased risk. Other risk factors are young age, nosocomial acquisition, prior hospitalization, and HIV infection. Day-care centers can facilitate the spread of resistant pneumococci and an Icelandic study showed that carriage of resistant pneumococci was associated with young age, domicile in an area with high antimicrobial consumption, recent antimicrobial use, frequent antimicrobial use, and use of trimethoprim-sulpha. The rapid increase of penicillin-resistant pneumococci in Iceland was met with propaganda against overuse of antimicrobials, which lead to reduction of antimicrobial use and subsequently a reduced incidence of penicillin-resistant pneumococci. This reduction may be related to reduced antimicrobial use. Reducing antimicrobial use should be considered important for programs aimed at reducing antimicrobial resistance.

Prevalence and patterns of resistance of Streptococcus pneumoniae strains isolated from carriers attending day care centers in the area of Athens

The prevalence and patterns of Streptococcus pneumoniae resistance to antibiotics was examined in 146 nasopharyngeal carrier strains obtained during April and May, 1997, from 382 healthy children attending eight day care centers (DCCs) in the area of Athens. Reduced susceptibility to at least one antibiotic was found in 32.6% as follows: penicillin 11.4% (intermediate), cefotaxime 0.8% (intermediate), trimethoprim-sulfamethoxazole 22.7%, erythromycin 13.6%, tetracycline 11.4%, chloramphenicol 8.3%. Most of the nonsusceptible to penicillin isolates belonged to serogroups 23, 9, and 19. Multidrug resistance was detected in 11.4% of S. pneumoniae isolates including five penicillin nonsusceptible serogroup 23 strains. More than half of the multidrug resistant strains were susceptible to penicillin and belonged to serogroups 6 (4), 23 (1), 19 (1), and 1(1). Strains that belonged to the same serogroup/serotype and had identical resistance patterns appeared to cluster in some DCCs. Antibiotic use in the previous month was associated with reduced susceptibility to penicillin (p = 0.007) and multidrug resistance (p = 0.012). In conclusion, a moderate prevalence of reduced susceptibility to penicillin in pneumococcal carrier strains was found in our community. Multidrug resistance was common and was often associated with susceptibility to penicillin. Several distinct patterns of resistance were observed, suggesting the spread of resistant clones to our country.

Introduction and clonal spread of penicillin- and trimethoprim/sulfamethoxazole-resistant Streptococcus pneumoniae, serotype 9V, in southern Sweden

As part of an intervention project, all patients in Malmöhus county with a culture positive for penicillin-resistant pneumococci, MIC > or =0.5 mg/L (PRP), have been registered since January 1995. Nasopharyngeal specimens were obtained from family members and close contacts of identified carriers. Children were denied attendance at regular day-care until PRP-negative. In 1995 and 1996, PRP were isolated from 882 individuals, 364 of whom had clinical infection and the remaining of whom were asymptomatic carriers. In 49%, the PRP were of serogroup 9, with MIC of penicillin 0.5-2.0 mg/L and resistance to trimethoprim/sulfamethoxazole. Further analyses with serotyping and genetic fingerprinting suggested strongly that most of the isolates belonged to a single serotype 9V clone. Month by month, an apparently continuous spread appeared from one municipality to a neighboring one. In most communities, the serotype 9V PRP appeared and disappeared within a few months. The active procedures of the intervention project may have limited the spread of the clone in the county.

Management of group A streptococcus pharyngitis with a second-generation rapid strep screen: Strep A OIA

Empirical therapy of presumed group A streptococcus (GAS) pharyngitis leads to unnecessary and inappropriate use of antibiotics and pressure for emergence of resistant strains of common bacteria. Immunoassay technology has produced several rapid tests for GAS. The wide variations in diagnosis and treatment of acute pharyngitis are reviewed including the impact of rapid strep tests. Published studies comparing Strep A OIA to routine agar culture and other rapid strep screens are presented to assess the reliability and applicability of this novel assay. These data suggest that Strep A OIA may be superior to the "gold standard" throat culture and other rapid streptococcal antigen detection assays. Judicious use of Strep A OIA can result in rapid, precise diagnoses and eliminate unnecessary and inappropriate use of antibiotics. Careful antibiotic selection can reduce the pressure for emergence of resistant bacteria. This innovative, effective assay can contribute to a lessening of this serious clinical challenge.

Carriage of respiratory tract pathogens and molecular epidemiology of Streptococcus pneumoniae colonization in healthy children attending day care centers in Lisbon, Portugal

In an effort to establish the rate of carriage of antibiotic resistant respiratory pathogens in children attending urban day care centers (DCC) in Portugal, seven DCC in Lisbon were selected for determining the rate of nasopharyngeal colonization of children between the ages of 6 months to 6 years by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Of the 586 children studied between January and March 1996, 47% carried S. pneumoniae, 72% H. influenzae, and 54% M. catarrhalis. Twenty-four percent of the pneumococci had reduced susceptibility to penicillin, and most of these belonged to serogroups 19, 23, 14, and 6. An additional 19% were fully susceptible to penicillin but showed decreased susceptibility to other antimicrobials. These isolates expressed serogroups 6, 11, 14, 18, 19, and 34. The majority (96%) of M. catarrhalis and 20% of H. influenzae were penicillin resistant due to the production of beta-lactamases. Recent antimicrobial use was associated with carriage of penicillin non-susceptible pneumococci and beta-lactamase producing H. influenzae (p < 0.05). Individual DCC differed substantially from one another in their rates of carriage of antibiotic resistant H. influenzae and S. pneumoniae. Characterization of antibiotic resistant S. pneumoniae isolates by molecular fingerprinting techniques showed that each DCC had a unique microbiological profile, suggesting little, if any, exchange of the resistant microbial flora among them. An exception to this was the presence of isolates belonging to two internationally spread epidemic clones: the multiresistant Spanish/USA clone expressing serotype 23F, and the penicillin and sulfamethoxazole-trimethoprim resistant French/Spanish clone (serotype 14) which were detected in four and three DCC, respectively.

Nasal carriage in Vietnamese children of Streptococcus pneumoniae resistant to multiple antimicrobial agents

Resistance to antimicrobial agents in Streptococcus pneumoniae is increasing rapidly in many Asian countries. There is little recent information concerning resistance levels in Vietnam. A prospective study of pneumococcal carriage in 911 urban and rural Vietnamese children, of whom 44% were nasal carriers, was performed. Carriage was more common in children <5 years old than in those >/=5 years old (192 of 389 [49.4%] versus 212 of 522 [40.6%]; P, 0.01). A total of 136 of 399 isolates (34%) had intermediate susceptibility to penicillin (MIC, 0.1 to 1 mg/liter), and 76 of 399 isolates (19%) showed resistance (MIC, >1.0 mg/liter). A total of 54 of 399 isolates (13%) had intermediate susceptibility to ceftriaxone, and 3 of 399 isolates (1%) were resistant. Penicillin resistance was 21.7 (95% confidence interval, 7.0 to 67.6) times more common in urban than in rural children (35 versus 2%; P, <0.001). More than 40% of isolates from urban children were also resistant to erythromycin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline. Penicillin resistance was independently associated with an urban location when the age of the child was controlled for. Multidrug resistance (resistance to three or more antimicrobial agent groups) was present in 32% of isolates overall but in 39% of isolates with intermediate susceptibility to penicillin and 86% of isolates with penicillin resistance. The predominant serotypes of the S. pneumoniae isolates were 19, 23, 14, 6, and 18. Almost half of the penicillin-resistant isolates serotyped were serotype 23, and these isolates were often multidrug resistant. This study suggests that resistance to penicillin and other antimicrobial agents is common in carriage isolates of S. pneumoniae from children in Vietnam.

Resistant bacteria in middle ear fluid at the time of tympanotomy tube surgery

This study was performed to determine the prevalence of resistant Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis isolated from middle ear fluid of children undergoing placement of ventilation tubes. The extent of resistance to commonly prescribed antibiotics and the risk factors associated with this resistance were also examined. Children who had fluid present in their middle ears at the time of ventilation tube placement from May 1996 to May 1997 were included in the study. Middle ear fluid was plated onto culture media in the operating room, and antimicrobial resistance of cultured organisms was ascertained. Risk factors for this resistance were determined from the medical history and analyzed. Cultures of 244 patients (355 ears) were positive for organisms in 29.6%. Penicillin resistance was found in 38.2% of S pneumoniae cultures. Beta-lactamase production was found in 65.1% and 100% of H influenzae and M catarrhalis specimens, respectively. Risk factor analysis revealed young age, day care attendance, and number of antibiotic courses to most reliably predict the presence of resistant microorganisms.

Duration of penicillin prophylaxis in sickle cell anemia: issues and controversies

Functional asplenia occurs in 94% of patients with homozygous sickle cell anemia by 5 years of age and may result in fatal septicemia due to encapsulated microorganisms such as Streptococcus pneumoniae. Penicillin prophylaxis in these patients significantly reduces the risk of septicemia; however, continuation of prophylaxis beyond 5 years of age is controversial, since the risk of developing septicemia is reduced after this age and prolonged prophylaxis may lead to emergence of penicillin resistance. Although reports of penicillin-resistant pneumococci in patients receiving penicillin prophylaxis are conflicting, the prevalence of these organisms in the general population in North America increased from 5% in 1989 to more than 35% in 1997. Discontinuation of prophylaxis after age 5 years may be recommended because of lack of benefit, difficulty maintaining compliance, reduced risk of developing pneumococcal bacteremia after that age, and increase in prevalence of penicillin-resistant pneumococci worldwide.

Antimicrobial-drug use and changes in resistance in Streptococcus pneumoniae

Resistance of Streptococcus pneumoniae to antimicrobial drugs is increasing. To investigate the relationship between antimicrobial use and susceptibility of S. pneumoniae isolates at 24 U.S. medical centers, we obtained data on outpatient antimicrobial-drug use for the regions surrounding 23 of these centers. We found an association between decreased penicillin susceptibility and use of beta-lactam antimicrobial drugs.

Antibiotic resistance in Streptococcus pneumoniae isolated from children

OBJECTIVE

To determine the level of antibiotic resistance in pneumoniae (S. pneumoniae) isolated from nasal swabs of healthy children.

METHOD

Cross-sectional community survey.

SETTING

Survey was undertaken in general practice settings in Canberra during March and April 1998.

SUBJECTS

Four hundred and sixty-one children under 3 years of age enrolled in general practice trial of clinical practice guidelines for antibiotic use.

OUTCOME MEASURES

Resistance to penicillin, erythromycin, co-trimoxazole, tetracycline, chloramphenicol and cefotaxime among the isolates of S. pneumoniae.

RESULTS

A total of 461 nasal swabs were collected and S. pneumoniae was isolated from 171 (37.1%). Penicillin resistance was found in 12.3% of these isolates, with high level resistance in 0.6%. Resistance rates were higher for cotrimoxazole (44.4%) and erythromycin (18.1%) than for penicillin. Multidrug resistance was found in 19% of these isolates. There was a significant association between the attendance at a day care centre and carriage of pneumococcus (53% vs 32%, odds ratio (OR) 2.4, 95% confidence interval (CI) 1.5-3.7, P < 0.001). Children who attended day care centers and had received antibiotics during the 4 months prior to swab collection were three times more likely to carry an antibiotic-resistant isolate than children who had neither attended a day care centre nor received antibiotics (68% vs 40%, OR 3.1, 95% CI 1.2-8.4, P = 0.02).

CONCLUSION

The level of antibiotic resistance in pneumococci from healthy children was of concern. Carriage of pneumococcus was significantly higher in children who attended a day care centre. Resistance was significantly correlated with antibiotic use in combination with day-care attendance. These findings warrant more judicious use of antibiotics in children.

Advances in antimicrobial therapy

Despite several decades of improved therapy and prevention of infectious diseases, infectious pathogens remain major causes of morbidity and mortality in humans worldwide. Among the most complex and daunting problems facing medical science is the evolution of antibiotic resistance among many common and once easily-treated infectious agents. This review summarizes the status of newer antimicrobial agents that have utility against pathogens infecting the central nervous system.

Nasopharyngeal carriage of multidrug-resistant Streptococcus pneumoniae in institutionalized HIV-infected and HIV-negative children in northeastern Romania

OBJECTIVES

The study compared nasopharyngeal carriage of resistant pneumoniae in human immunodeficiency virus (HIV)-seropositive and -seronegative children.

METHODS

Nasopharyngeal colonization with Streptococcus pneumoniae was investigated during May 1996 in 162 HIV-negative infants and children (age range, 1-38 mo) and 40 HIV-infected children (age range, 39-106 mo) living in an orphanage in Iasi, northeastern Romania. The HIV-infected children lived separated from the other children and were cared for by a different staff. Streptococcus pneumoniae was isolated from 12 of 40 (30%) HIV-infected and from 81 of 160 (50%) HIV-negative children. Antimicrobial susceptibility to penicillin and ceftriaxone was determined by E-test, and to another five antibiotics by disk diffusion. Serotyping was performed by the Quellung method on 81 of 93 (87%) isolates.

RESULTS

Serotypes 6A, 6B, 19A, and 23F together represented 98% of all isolates. Ninety-nine percent of S. pneumoniae isolates were resistant to penicillin, and 74% were highly resistant to penicillin (minimum inhibitory concentration [MIC] > 1 mg/mL); MIC50 and MIC90 to penicillin of the isolates were 2 mg/mL and 8 mg/mL, respectively. Eighty-nine of ninety-one isolates were susceptible to ceftriaxone; 99%, 87%, 87%, 48%, and 21% of the isolates were resistant to trimethoprim-sulphamethoxazole, erythromycin, clindamycin, tetracycline, and chloramphenicol, respectively. Eighty-two (89%) isolates were multidrug resistant (resistant to =/>3 antibiotic classes); 37 of 92 (40%) isolates were resistant to 5 or more antibiotic classes, and 16 of these 37 (43%) belonged to serotype 19A. All serotype 19 isolates were highly resistant to penicillin.

CONCLUSIONS

No significant differences were observed in the resistance rates of S. pneumoniae in HIV-infected children compared to HIV-negative children. Multidrug-resistant pneumococci were highly prevalent in this Romanian orphanage in both HIV-negative and older HIV-infected children. The observed high prevalence of multidrug-resistant pneumococci (coupled with high penicillin resistance) with a limited number of circulating serotypes emphasizes the need to further evaluate the conjugate vaccines in children at risk for invasive pneumococcal infection.

Carriage of multidrug-resistant Streptococcus pneumoniae and impact of chemoprophylaxis during an outbreak of meningitis at a day care center

Three cases of meningitis due to multidrug-resistant serotype 14 Streptococcus pneumoniae occurred at a day care center (DCC) over 5 days. Cultures of nasopharyngeal samples were done at the index DCC, 2 comparison DCCs, and a pediatrics practice. Isolates were serotyped and subtyped by pulsed-field gel electrophoresis (PFGE) with SmaI. Pneumococcal carriage rates ranged from 44%-65% at the 3 DCCs and 29% in the pediatrics practice. Carriage of multidrug-resistant serotype 14 S. pneumoniae was noted in 13%-19% of children at the 3 DCCs. An outbreak strain was identified by PFGE at the index DCC and 1 other DCC; a closely related strain was found in the third DCC. Carriage of the outbreak strain was associated with being age 0-24 months, antibiotic use, upper respiratory tract infections, and otitis media. DCC contacts of the ill children were offered chemoprophylaxis with rifampin and clindamycin, which produced a profound but transient decrease in carriage. No additional cases occurred.

Marked differences in pneumococcal carriage and resistance patterns between day care centers located within a small area

Carriage rates of Streptococcus pneumoniae and their antibiotic resistance, capsular types, and genetic patterns were studied among 264 children aged 12-35 months attending 8 day care centers located within a 2.5-mile radius in the same city. Nasopharyngeal cultures were obtained within a 2-month interval from all 264 children. Significant differences in each of the studied characteristics were found between day care centers, and each day care center had a unique pattern of the carried pneumococci. Our findings show that day care centers are independent microenvironments and emphasize their role in the transmission and augmentation of antibiotic-resistant S. pneumoniae in the community.

Bacterial meningitis

In recent years, investigators have made significant advances in understanding the pathogenesis of bacterial meningitis, particularly with regard to understanding the cascade of biologic events that cause excessive inflammation within the central nervous system (CNS). Nevertheless, the most important event in the field of bacterial meningitis in the past decade is the dramatic decline in the incidence of Haemophilus influenzae meningitis in children as a result of the widespread use of the conjugated H. influenzae type b vaccine. Currently, the most important clinical challenge in this field is the emergence of the drug-resistant Streptococcus pneumoniae. This problem has significantly complicated initial management of patients with suspected bacterial meningitis. Preliminary data show promise with new conjugated S. pneumoniae vaccines.

The bacteriology of the nasopharynx in childhood

Non-typeable Haemophilus influenzae and Streptococcus pneumoniae (Pnc) are frequently isolated from the nasopharynx (NP) of young healthy children. Colonization of the NP may be detected in early infancy with peaks toward the second year of life. NP carriage of Pnc and especially of antibiotic-resistant Pnc is common and plays an important role in its spread in children, its prevalence increases in those coming into close contact, such as children attending day-care facilities. Several studies show that the presence of older siblings, antibiotic treatment during the month preceding the culture and the attendance at a large day-care center are associated with carriage of drug-resistant Pnc. Significant changes may occur early during antibiotic treatment, and these changes may vary with the use of different antibiotics. Also new strains of Pnc not detected initially emerge, and newly detected organisms are most often resistant to the administered drug. Nasopharyngeal colonization with resistant bacteria was shown to be associated with an increased incidence of acute otitis media with resistant organisms and growing incidence of unresolved otitis media. Preliminary studies show that conjugate pneumococcal vaccine might reduce the nasopharyngeal pneumococcal carriage in general, and of resistant organisms in particular.

Nosocomial pneumococcal infection: an outbreak

When an outbreak of pneumococcal disease occurs an institution--be it a hospital, nursing home, day care center, or other facility--management includes treatment of affected cases and prevention of new cases. Patients and staff should be tested for nasopharyngeal carriage and their vaccination status ascertained. Antibiotic use should be reviewed, especially if the causative strain is resistant.

Therapy for pneumococcal infection at the millennium: doubts and certainties

Rapidly burgeoning worldwide multiple drug-resistant pneumococcal serotypes pose an urgent demand for new management approaches. Perhaps modern intensive care methods may have alternatives to offer. Indeed, standard assessments such as the admission APACHE II score may overestimate individual risk of death in severe CAP, and mortality can be reduced. However, among those at highest risk for mortality in the early phase of invasive disease, the conclusions reached 2-3 decades ago, that it is questionable whether a more effective drug than penicillin can be developed, and that a reduction in the number of deaths consequent to this infection can be accomplished only by widespread immunoprophylactic measures, remain inescapable. Clearly, as discussed elsewhere in this supplement, the continuing validity of these 20-year-old conclusions and the global prevalence of DRSP demand the development and marketing of new conjugate vaccines, although more widespread use of the existing 23-valent polysaccharide vaccine among high-risk populations is essential in the interim. With respect to resistance selection pressures, antibiotic prescription control may provide the answer. However, patient expectations of antibiotic therapy for trivial respiratory infection is high and, in the United Kingdom, 75% of previously healthy adults will receive it; those who do not will usually consult another physician in an effort to secure such therapy. Thus, without the intervention of government or managed care organizations, self-regulation in prescribing is unlikely. The evidence for beta-lactam treatment failure in meningitis has led to alternative approaches, with vancomycin as the primary agent. Penicillins may remain effective for otitis media, but oral cephalosporins are suspect. Data on pediatric pneumococcal pneumonia continue to suggest use of beta-lactams, at least for disease caused by strains with intermediate penicillin sensitivity. Pallares et al concluded that penicillins and cephalosporins remain the drugs of choice for severe pneumococcal pneumonia in adults. Others who share this conclusion often cite that study as evidence. However, in the case of penicillins, the mortality rate was 6% higher in a subgroup selected for monomicrobial infection and reduced risk factors for mortality when penicillin-resistant infection was present, and the overall mortality was 14% higher with penicillin-resistant strains (taking into account "all comers"). Those who depend on the findings of evidence-based medicine may accept the premise that penicillins and cephalosporins remain the drugs of choice, and agree with Goldstein and Garau that it would indeed be a mistake to adopt alternative therapies. Others may consider the deaths of 6 of 100 patients who were not in the highest-risk group too high a price to pay for statistical significance and may be skeptical of the continued use of beta-lactam therapy on higher-risk patients. In addition, the persistent selection pressure applied by continued use of beta-lactams offers a powerful population-based argument for alternatives. As DRSP continues to spread and resistant strains with penicillin MIC >2 mg/L become more prevalent, new agents such as the azabicyclo-methoxyquinolone, moxifloxacin, and perhaps grepafloxacin, but not the more toxic sparfloxacin and trovafloxacin, will undoubtedly flourish as treatments for CAP. By that time, the results of clinical studies on ketolides and oxazolidinones could offer further choices.

Penicillin-nonsusceptible pneumococcus in acute otitis media in New York City

OBJECTIVE

To determine the proportion of children with acute otitis media (AOM) presenting in our catchment area in New York City who were infected with nonsusceptible Streptococcus pneumoniae and to determine the susceptibility of these organisms to penicillins and other antibiotics commonly used to treat AOM.

SETTING

Ambulatory clinics and the emergency department of a tertiary care, inner-city medical center.

PATIENTS

During a 2-year period from 1993 to 1995, 115 children (aged 6 months to 12 years) with AOM underwent tympanocentesis. Patients did not receive antibiotics for at least 1 week before tympanocentesis.

RESULTS

Thirty-one children were infected with S pneumoniae, and 83.9% of isolates were susceptible to penicillin. Of the 16.1% strains that were nonsusceptible, most (4 of 5 strains) were intermediately resistant, and only 1 exhibited high-level resistance to penicillin. Of all the cephalosporins tested, only cefotaxime had consistent activity against the intermediately resistant strains. Notably, all nonsusceptible pneumococci were inhibited by macrolides.

CONCLUSIONS

This study provides unique reference data for nonsusceptible Streptococcus pneumoniae in children with AOM and documents that newer cephalosporin agents are not active against all of these strains.

Indication-based use of antimicrobials in Finnish primary health care. Description of a method for data collection and results of its application

OBJECTIVE

To collect population-based information on treatment of infections with antibiotics in PHC.

DESIGN

A questionnaire study for general practitioners (GPs).

SETTING

All health centres of Pirkanmaa Hospital District in Finland.

PATIENTS

Patients with any infection attending health centre during 1 week in November 1994.

MAIN OUTCOME MEASURES

An infection diagnosis by the GP.

RESULTS

A total of 4150 questionnaires were received from 223 doctors. Respiratory tract infections comprised 80% of all infections. Of all patients 64% received antimicrobial treatment. Unspecified upper respiratory tract infections and pharyngitis were rarely treated with antimicrobials (10 and 21%, respectively), whereas patients with acute bronchitis received antibiotics as often (83%) as patients with otitis media (93%) or tonsillitis (86%). The most commonly prescribed substances were cephalosporins (19% of all antimicrobials), penicillin V (17%), and amoxycillin (17%). Half of the cephalosporin use could be regarded as overuse. Half of the sulphatrimethoprims were used for otitis media. A quarter of the patients expressed a desire to receive antibiotic treatment.

CONCLUSION

The method was practical, inexpensive, and successful in giving such information, which is needed for supervising the rational use of antibiotics in primary health care.

One dose ceftriaxone vs. ten days of amoxicillin/clavulanate therapy for acute otitis media: clinical efficacy and change in nasopharyngeal flora

OBJECTIVE

To compare the efficacy and the safety of a single intramuscular dose of ceftriaxone, 50 mg/kg, vs. a 10-day course of amoxicillin/clavulanate (amox/clav) therapy, 80 mg/kg/day of amoxicillin: 10 mg/kg/day of clavulanate in three divided doses, in children with acute otitis media (AOM) and to evaluate the changes in nasopharyngeal flora after treatment.

METHODS

In a prospective, comparative, open randomized, multicenter trial, children were scheduled to return for visits on Days 12 to 14 (main end point) and Days 28 to 42 after the beginning of treatment for AOM. A nasopharyngeal swab for bacterial culture was obtained before the treatment and at Days 12 to 14.

RESULTS

Between February, 1995, and May, 1996, 513 children with a mean age of 14.2 +/- 6.7 months were enrolled. All the patients were evaluable for the safety and intent-to-treat analyses and 463 for the per protocol efficacy. At Days 12 to 14 clinical success was obtained in 186 of the 235 children (79%) given ceftriaxone and in 188 of the 228 children (82.5%) treated with amox/clav. Among the patients with clinical success on Days 12 to 14, the success was maintained at Days 28 to 42 for 108 of 183 (59%) patients in the ceftriaxone group and 103 of 187 (55%) patients in the amox/clav group. Before the antibiotic treatment the percentages of children carrying Streptococcus pneumoniae (59.1%), Haemophilus influenzae (39.4%), Moraxella catarrhalis (55.7%) and the rate of penicillin-resistant S. pneumoniae (52.2%) were comparable between the 2 groups. At Days 12 to 14 the carriage of S. pneumoniae and M. catarrhalis was significantly different between the patients treated with ceftriaxone, 43.9 and 42.2, respectively, and the patients treated with amox/clav, 17.4 and 11.1%, respectively. Among the children carrying S. pneumoniae at Days 12 to 14, the percentage of penicillin-resistant strains reached 63.4% in the ceftriaxone treatment group and 83.0% in the amox/clav treatment group, (P = 0.02). Adverse events (mainly diarrhea) related to the study medication were reported more frequently (P < 0.0001) in the amox/clav treatment group.

CONCLUSIONS

In an area with a high rate of penicillin-resistant S. pneumoniae, a single dose of ceftriaxone is as efficient as a 10-day course of amox/clav in the treatment of AOM in young children. There was for the two regimens an increased rate of penicillin-resistant strains among the pneumococci carried, whereas the chance for a child to carry a penicillin resistant S. pneumoniae did not increase after treatment.

The relationship between perceived parental expectations and pediatrician antimicrobial prescribing behavior

CONTEXT

Despite growing concern over the escalating antimicrobial resistance problem, physicians continue to inappropriately prescribe. It has been suggested that a major determinant of pediatrician antimicrobial prescribing behavior is the parental expectation that a prescription will be provided.

OBJECTIVES

To explore the extent to which parental previsit expectations and physician perceptions of those expectations are associated with inappropriate antimicrobial prescribing; and to explore the relationship between fulfillment of expectations and parental visit-specific satisfaction.

DESIGN

Previsit and postvisit survey of parents and postvisit survey of physicians.

SETTING

Two private pediatric practices, one community based and one university based.

PARTICIPANTS

Ten physicians (response rate = 77%), and a consecutive sample of 306 eligible parents (response rate = 86%) who were attending sick visits for their children between October 1996 and March 1997. Parents were screened for eligibility in the waiting rooms of the two practices and were invited to participate if they spoke and read English and their child was 2 to 10 years old, had a presenting complaint of ear pain, throat pain, cough, or congestion, was off antimicrobial therapy for the past 2 weeks, and was seeing one of the participating physicians.

MAIN OUTCOME MEASURES

Antimicrobial prescribing decision, probability of assigning a bacterial diagnosis, and parental visit-specific satisfaction.

RESULTS

Based on multivariate analysis, physicians' perceptions of parental expectations for antimicrobials was the only significant predictor of prescribing antimicrobials for conditions of presumed viral etiology; when physicians thought a parent wanted an antimicrobial, they prescribed them 62% of the time versus 7% of the time when they did not think the parent wanted antimicrobials. However, physician antimicrobial prescribing behavior was not associated with actual parental expectations for receiving antimicrobials. In addition, when physicians thought the parent wanted an antimicrobial, they were also significantly more likely to give a bacterial diagnosis (70% of the time versus 31% of the time). Failure to meet parental expectations regarding communication events during the visit was the only significant predictor of parental satisfaction. Failure to provide expected antimicrobials did not affect satisfaction.

CONCLUSIONS

The antibiotic resistance epidemic should lead to immediate replication of this study in a larger more generalizable population. If inaccurate physician perceptions of parent desires for antimicrobials for viral infections are confirmed, then an intervention to change the way physicians acquire this set of perceptions should be undertaken.