Antibiotic Resistance in Preschool Children Assignment.
Antibiotic resistance is associated with prior receipt of antibiotics. An analysis of linked computerized databases for physician visits and antibiotic prescriptions was used to examine antibiotic
prescribing for different respiratory infections in preschool children in Canada. In 1995, 64% of
61,165 children aged <5 years made 140,892 visits (mean, 3.6 visits per child) for respiratory infections; 74% of children who made visits received antibiotic prescriptions. Antibiotics were prescribed to 49% of children with upper respiratory tract infection, 18% with nasopharyngitis, 78% with pharyngitis or tonsillitis, 32% with serous otitis media, 80% with acute otitis media, 61% with sinusitis, 44% with acute laryngitis or tracheitis, and 24% with influenza. Antibiotic Resistance in Preschool Children Assignment.Acute otitis media accounted for 33% of all visits and 39% of all antibiotic prescriptions. The estimated Canadian- dollar cost of overprescribing was $423,693, or 49% of the total cost of antibiotics ($859,893) used in this group. This population-based study confirms antibiotic overprescribing in Canada. In the 50 years since the introduction of penicillin, there has been the perception of control of many microbial diseases. Antibiotic Resistance in Preschool Children Assignment. However, in the 1990s, the rise of antimicrobial resistance among common organisms—such as the nonsusceptibility to penicillin of 25% of Streptococcus pneumoniae strains isolated in the United States  and of .50% of those isolated in Spain , Italy , and Hungary — has caused alarm about the public health threat of emerging infectious diseases and anti- microbial resistance. There is a strong association between prior receipt of anti- biotics and development of antibiotic resistance [5–10]. Respi- ratory tract infections account for three-quarters of all antibi- otic prescriptions . Data collected from a pediatric group practice , a Kentucky Medicaid-claims database , and an analysis of pediatric antibiotic prescribing in the National Ambulatory Medical Care Survey  suggest that 50% of children who see a physician for a viral respiratory tract infec- tion receive antibiotics. The amount of increase in antibiotic prescription in Europe varies, with a lower rate in the United Kingdom than in Germany or France . In Canada, the number of antibiotic prescriptions filled in 1996 was 26.3 million , in a total population of nearly 30 million . To determine the magni- tude of antibiotic prescribing for specific respiratory tract in- fections, data from the Saskatchewan Health Databases focus- ing on young children ,5 years of age were obtained for the year 1995. Antibiotic Resistance in Preschool Children Assignment.This age group was targeted because children, particularly those ,5 years of age, receive antibiotics more frequently than those in older age groups [18, 19]. We also examined patterns of use, costs of antibiotics, rates of inappro- priate antibiotic prescribing, and associated hospitalizations. Methods Saskatchewan Health Databases Saskatchewan, a province in western Canada, had a total population of 1,015,200 in 1995 . As in all Canadian provinces, Saskatchewan residents have universal health care access through provincially funded health insurance. Physician claims, outpatient prescription-drug claims, hospital dis- charges, and health insurance registration can be linked across administrative databases and over time by means of the unique number assigned to each Saskatchewan Health beneficiary . The administrative databases included prescribing infor- mation for the total population of Saskatchewan, with the single exception of registered American Indians. As of 30 June 1995, 61,165 registrants eligible for prescription drug benefits were ,5 years of age. Saskatchewan has a relatively restricted formulary for anti- biotics for treatment of respiratory tract infections; it includes amoxicillin, ampicillin, penicillin V and G benzathine, clox- acillin, erythromycin, cefixime, cephalexin, and tetracycline. Physicians wishing to prescribe agents such as amoxicillin/ clavulanate, cefaclor, cefuroxime, clarithromycin, and the Received 3 November 1998; revised 24 February 1999. Antibiotic Resistance in Preschool Children Assignment. The interpretation and conclusions contained herein represent those of the authors and do not necessarily represent those of the Government of Saskatche- wan or the Saskatchewan Department of Health. Financial support: The study was funded by grants-in-aid from Abbott Lab- oratories Ltd. Canada, Bristol-Myers Squibb Canada, and Hoechst Marion Roussel Canada. Reprints or correspondence: Dr. Elaine E. L. Wang, Clinical and Medical Affairs, Pasteur Merieux Connaught, 1755 Steeles Avenue West, Toronto, Ontario, Canada M2R 3T4 (email@example.com_vacc.com). Clinical Infectious Diseases 1999;29:155– 60 © 1999 by the Infectious Diseases Society of America. All rights reserved. 1058 – 4838/99/2901– 0024$03.00 155 by guest on July 13, 2011cid.oxfordjournals.orgDownloaded from quinolones must fill in forms for "Exception Drug Status" coverage before their patients may receive these agents through the drug plan. The above administrative databases were examined to ex- tract a subgroup of patients whose diagnoses could be classified as respiratory tract infections with use of the International Classification of Diseases (ICD-9-CM) diagnostic codes . Codes corresponded to the following diagnoses: serous (381) and acute suppurative (382) otitis media, common cold (460), acute sinusitis (461), acute pharyngitis (462), acute tonsillitis (463), acute laryngitis (464), acute upper respiratory tract in- fection (URI; 465), acute bronchitis or bronchiolitis (466), pneumonia (including viral, pneumococcal, and other bacterial pneumonia, pneumonia due to another specific organism, pneu- monia without a causative organism specified, and broncho- pneumonia) (480 –486), and influenza (487). Only one diagnostic code was allowed for each visit. If there were multiple diagnoses at the visit and an antibiotic was prescribed, it was assumed that the diagnostic code accurately reflected the infection most likely to be of bacterial origin and therefore likely to respond to antibiotics. An antibiotic prescription was attributed to a specific respiratory diagnosis when it was filled within 7 days of the physician-patient encounter. When there were several visits during a 7-day period, the prescription was attributed to the diagnosis made at the most recent visit. The cost of the prescription (which, for purposes of the study, consists of the acquisition cost, the markup, and the dispensing fee) was summarized in 1995 Canadian dollars. Appropriateness of Antibiotic Prescriptions Wherever possible, antibiotic appropriateness was deter- mined on the basis of evidence-based guidelines. These in- cluded recent publications of a consensus group consisting of members of the Centers for Disease Control and Prevention (Atlanta), the American Academy of Pediatrics, and the Amer- ican Academy of Family Practice, dealing with otitis media, nasopharyngitis, bronchitis, pharyngitis, and sinusitis [22–27]. In the guideline for pharyngitis, it was noted that 85% of acute pharyngitis is of viral etiology, for which antibiotics are not indicated . ORDER A CUSTOM-WRITTEN PAPER HERE For conditions not reviewed by the above group, further information was gathered from other consensus guidelines or reference textbooks. Antibiotic Resistance in Preschool Children Assignment.For many of the conditions, there have not been clinical trials of antibiotic management, which would offer evidence of the highest quality to indicate efficacy of an intervention . In such situations, data on etiologic agents and appropriateness of antibiotics for treatment against such agents were used. However, these data constitute a lower level of evidence than that from randomized trials. Acute bronchiolitis is a viral infection in which secondary bacterial infections are rare, and there is no benefit from antibiotic treatment, according to the single randomized clini- cal trial examining this question . Thus, an expert Canadian consensus panel recommended against the use of antibiotics in initial management of bronchiolitis . Another Canadian consensus panel has recommended against antibiotic treatment when viral pneumonia is suspected on the basis of epidemio- logical factors, presence of wheezing, or identification of viral etiology through antigen detection . Otherwise, antibiotics are recommended. A single ICD-9-CM code applies for acute laryngitis, croup, and tracheitis. Acute laryngitis is a viral infection, for which antibiotics are not indicated. Croup is managed with supportive therapy, racemic epinephrine, or systemic or inhaled steroids as necessary, but not antibiotics . Both epiglottitis and bacte- rial tracheitis are bacterial infections for which antibiotics are indicated, but they are extremely rare and present as acute serious illness. Therefore, we considered the following as inappropriate indications for antibiotics: nonspecific URI, the common cold, serous otitis media, acute bronchitis or bronchiolitis, laryngitis, and influenza; in addition, we considered 85% of antibiotics prescribed for pharyngitis or tonsillitis to be inappropriate. Given difficulties in differentiating etiologic agents in pneumonia, the heterogeneous nature of other respiratory infections, and the benefit of antibiotic treatment of acute otitis media and sinusitis, these conditions were considered appropriate indications for antibiotic treatment. Results A total of 140,892 visits were made during the 1995 calendar year by 38,848 children in Saskatchewan (3.62 visits per child), of whom 28,929 (74%) received at least one course of antibi- otic. The number of visits and the frequency of antibiotic prescribing are listed in table 1. Because a subject may have had more than one physician visit for a diagnosis, the number of subjects and the frequency of prescribing per subject are also included. Figure 1 shows the distribution of subjects prescribed anti- biotics, according to illness syndrome and costs of those anti- biotics. The most frequent reason for a visit and for an antibi- otic prescription was treatment of acute otitis media, accounting for 39% of all antibiotics prescribed. The penicillin class of antibiotics, including ampicillin, re- mains the most frequently prescribed. There was variation in the next most frequently used class of antibiotics, depending on the clinical diagnosis (figure 2). Specifically, trimethoprim- sulfamethoxazole (co-trimoxazole) was the next most fre- quently used agent for acute otitis media, and erythromycin was next most frequently used antibiotic for acute URI, pneu- monia, and pharyngitis or tonsillitis. Antibiotic Resistance in Preschool Children Assignment. The mean (6SD) antibiotic cost per patient, as shown in table 2, varied from $13.04 (67.04) for a patient with a common cold to $23.84 (621.08) for a patient with acute otitis 156 Wang et al. CID 1999;29 (July) by guest on July 13, 2011cid.oxfordjournals.orgDownloaded from media. Patients with pneumonia were excluded from this com- parison because the use of antibiotics in the hospital was not captured. Associated hospitalizations for the same diagnosis within 30 days were generally uncommon. They occurred with 172 (0.4%) of the visits for acute URI; 53 (0.3%) of the visits for pharyngitis or tonsillitis; 371 (4.4%) of the visits for bronchitis or bronchiolitis; no visits for a common cold; 25 (0.5%) of the visits for serous otitis media; 223 (0.5%) of the visits for acute otitis media; 356 (9.4%) of the visits for acute laryngitis/ tracheitis; 272 (6.4%) of the visits for pneumonia; 9 (0.4%) of the visits for influenza; no sinusitis visits; and 86 (2.2%) of the visits for other respiratory conditions. With the exception of acute bronchitis or bronchiolitis, acute laryngitis or tracheitis, and pneumonia, morbidity for the other syndromes is low, as indicated by low associated hospitalization rates. Antibiotic Resistance in Preschool Children Assignment. If the evidence-based management guidelines were fol- lowed, antibiotics should have been withheld from all patients with acute URI, acute bronchitis and bronchiolitis, the common cold, influenza, serous otitis media, and acute laryngitis. One could also withhold antibiotics from 85% of those with acute tonsillitis or pharyngitis. Under these assumptions, 33,680 of a total of 66,419 courses of antibiotics (51%) could have been eliminated in 1995. The cost of overprescribing is in the order of $423,693, 49% of the $859,893 total expenditure for outpa- tient antibiotics for respiratory tract infections in this age group. Acute otitis media was the most common diagnosis contributing to antibiotic prescription costs, accounting for $369,296. Discussion Provincial health insurance allows Canadians to have return visits to their physicians without the burden of out-of-pocket Table 1. Frequency of diagnoses and antibiotic prescriptions for Canadian preschool children. Appropriateness of antibiotic prescription; diagnosis No. of visits Percentage of visits resulting in prescription No. of subjects Percentage of subjects receiving antibiotics Usually inappropriate Acute URI 43,160 36 23,255 49 Acute bronchitis or bronchiolitis 8,504 50 5,473 65 Common cold 5,963 16 4,743 18 Serous otitis media 5,039 21 2,515 32 Acute laryngitis, croup 3,795 34 2,647 44 Influenza 2,340 22 1,971 24 Possibly inappropriate Acute pharyngitis or tonsillitis 16,445 69 12,322 76 Usually appropriate Other respiratory condition 3,887 32 3,157 35 Acute otitis media 46,789 57 19,359 80 Pneumonia 4,251 33 2,488 51 Acute sinusitis 693 56 588 61 NOTE. URI 5 upper respiratory tract infection. Figure 1. Contribution to total antibiotic prescription costs for re- spiratory infections, by diagnosis (URI 5 upper respiratory tract in- fection). Antibiotic Resistance in Preschool Children Assignment. 157Antibiotic Overprescribing for Preschool ChildrenCID 1999;29 (July) by guest on July 13, 2011cid.oxfordjournals.orgDownloaded from costs, a practice that may lead to differences in the frequency of antibiotic prescribing as compared with that in the United States. The strength of these observations lies in the ability of the Saskatchewan Health Databases to capture the vast majority of all physician visits and outpatient antibiotic prescriptions. Our finding that ;50% of antibiotics prescribed are not indi- cated on the basis of evidence-based guidelines is remarkably consistent with rates reported from the United States [11–13, 33]. In the United Kingdom, antibiotic prescribing increased by 46% between 1980 and 1991 , and overprescribing in general practice, especially for antibiotics, is estimated to cost 275 million pounds annually . Half of all antibiotic pre- scriptions in the United Kindgom were for respiratory tract infections . Thus, our findings likely have wide generaliz- ability. Antibiotic Resistance in Preschool Children Assignment. There were limitations to our study. The disease to which the antibiotic is attributed is dependent on the diagnostic code indicated on the physician claim form. For the purpose of determining antibiotic appropriateness, the listed diagnosis was assumed to be the indication for the antibiotic. Because claim forms allow only one disease code to be entered, it is possible that an uncoded illness was in fact the one for which antibiotics were indicated. We have observed in another study of prescrib- ing by pediatricians for respiratory tract infection that these codes may be incorrect in up to 41% of cases when compared with chart diagnoses . It was assumed that physicians' diagnoses were correct. Physicians may diagnose certain conditions as bronchitis, si- nusitis, or otitis media to justify antibiotic prescriptions [37, 38]. Antibiotic Resistance in Preschool Children Assignment.This would lead to an underestimate of inappropriate antimicrobial prescribing. Another limitation of this study is the inability to capture antibiotic treatment initiated during a hospitalization. The low rates of antibiotic prescription for pneumonia, for example, are likely due to a selection bias to include milder cases or are due to capture of follow-up visits during recovery. One would predict that most patients with pneumonia had been hospital- ized, and antibiotics initiated in that setting are not captured in the databases included in this study. It is assumed that many of the visits were follow-up visits, when no further antibiotic courses were being prescribed. It is not possible to differentiate multiple visits for the same illness vs. single visits for illnesses recurring in the same year. Because physicians often have patients with acute otitis media or sinusitis return for follow-up visits, this may explain the low rate of prescribing for acute otitis media and sinusitis, as the second visit usually does not prompt a subsequent antibiotic prescription. Similarly, it is not possible to determine whether some of the antibiotic courses were prescribed only at the second visit, because of lack of improvement. Antibiotic Resistance in Preschool Children Assignment. The estimate in the guidelines that 85% of pharyngitis cases are of viral etiology was based on studies that included older children . In this population of young children, the propor- tion of pharyngitis that is viral in origin may be closer to 100%. Thus, the estimate of antibiotic overuse for viral infections may be low. The relatively restricted formulary in Saskatchewan likely lowers the cost of agents and limits the variation in types of antibiotics prescribed through the drug plan. Where there is a larger number of drugs included in a formulary, one could predict greater use of newer, more expensive agents. Further- more, actual prescribing may be underestimated in that the databases capture only antibiotic prescriptions that are actually filled; if prescriptions were not filled by families, they would not be noted in the database. Antibiotic Resistance in Preschool Children Assignment. Only a single year was sampled, which fell during a period before media reports of increasing antibiotic resistance and of Figure 2. Number of prescriptions, per antibiotic class, used in treatment of common respiratory infections (Erythro-sulfa 5 eryth- romycin-sulfisoxazole; URI 5 upper respiratory tract infection). Table 2. Antibiotic treatment costs (in 1995 Canadian $), by diag- nosis, for preschool children in Canada. Diagnosis Mean cost/patient (SD) Total antibiotic cost for 1995 Acute URI 17.08 (11.97) 192,813 Acute bronchitis or bronchiolitis 16.37 (10.42) 58,017 Common cold 13.04 (7.04) 10,977 Serous otitis media 20.63 (15.51) 16,587 Acute laryngitis 14.25 (7.63) 16,744 Influenza 13.82 (6.75) 6,606 Acute pharyngitis or tonsillitis 16.83 (11.77) 143,475 Other respiratory condition 14.92 (9.11) 16,488 Acute otitis media 23.84 (21.08) 369,296 Pneumonia 18.46 (10.81) 23,133 Acute sinusitis 16.09 (13.19) 5,759 Total 859,893. Antibiotic Resistance in Preschool Children Assignment. NOTE. URI 5 upper respiratory tract infection. 158 Wang et al. CID 1999;29 (July) by guest on July 13, 2011cid.oxfordjournals.orgDownloaded from educational efforts aimed at reducing inappropriate antibiotic prescribing. A follow-up study is warranted to determine whether some of these educational and media efforts directed toward parents have substantially affected antibiotic prescription rates. Antibiotic Resistance in Preschool Children Assignment. Comparisons of prescribing by type of physician (pediatri- cian vs. family practitioner) were not made. A higher rate of inappropriate antibiotic prescribing has been described with regard to family practitioners than to pediatricians in the man- agement of acute laryngotracheobronchitis  and purulent nasopharyngitis . However, in Saskatchewan, the majority of primary care of children is delivered by family practitioners, while pediatricians are mainly consultants. Antibiotic Resistance in Preschool Children Assignment. Despite study limitations, the major contribution to antibi- otic exposure is obvious for inappropriate antibiotic therapy for frequently seen nonbacterial conditions such as acute URI. With use of evidence-based guidelines, almost half of the costs incurred for antibiotic treatment of respiratory infections could have been saved. There was also inappropriate selection of antibiotics, which suggests a lack of differentiation between illness syndromes by some prescribers. For example, ;6% of children with pharyngitis received trimethoprim-sulfamethoxazole, which would not be appropri- ate for treatment against group A streptococci. However, after penicillins there is a difference in the next most frequent antibiotic used for different syndromes, suggesting that most physicians do consider the syndromes different. Such substantial savings would be supplemented by the savings associated with the occurrence of fewer infections due to antibiotic- resistant organisms, which cause twice as much morbidity and mortality than susceptible organisms causing the same infections . Antibiotic Resistance in Preschool Children Assignment. A number of factors other than the clinical condition influ- ence antibiotic prescribing. Such factors include lack of cer- tainty of diagnosis , heavy workload and inadequate time for each patient , fear of litigation for not treating a bac- terial infection, the belief that antibiotics are innocuous, social and psychological characteristics of the patient , and per- ceived pressure from parents to prescribe [44– 46]. Guidelines must be adapted for use in the office-based setting, with rec- ognition of the existence of these potential obstacles. The acceptance of these practice guidelines by both the general public and physicians may be enhanced if the guidelines stress the harm of inappropriate antibiotic prescription . Acknowledgments Data abstraction was performed under the supervision of Mary- Rose Stang, Ph.D. (consultant, Research Services, Saskatchewan Health). This study was based in part on data provided by the Saskatchewan Department of Health. Antibiotic Resistance in Preschool Children Assignment. Worldwide in 2013, 935,000 children younger than 5 years of age die of pneumonia, and in sub-Saharan Africa an estimated 16% of child deaths are attributed to pneumonia (1). Bacteria such as Streptococcus pneumoniae, Haemophilus influenzae type b (Hib), and Staphylococcus aureus are responsible for the majority of these infections, but also viruses, parasites, and fungi can cause pneumonia Correspondence: Karin Ka¨llander, Division of Global Health, Tomteboda va¨gen 18A, Karolinska Institutet, SE-171 77 Stockholm, Sweden. E-mail: Karin.firstname.lastname@example.org (Received 15 February 2015; revised 8 July 2015; accepted 9 July 2015) ISSN 0300-9734 print/ISSN 2000-1967 online 2015 Taylor & Francis. This is an open-access article distributed under the terms of the CC-BY-NC-ND 3.0 License which permits users to download and share the article for non-commercial purposes, so long as the article is reproduced in the whole without changes, and provided the original source is credited. Antibiotic Resistance in Preschool Children Assignment. DOI: 10.3109/03009734.2015.1072606 (2,3). Reducing the pneumonia death toll requires preventive interventions (e.g. adequate nutrition and immunizations), but the main difference between life and death for a child sick with pneumonia hinges on prompt and appropriate treatment with an effective drug (4). Yet in 2012 UNICEF published Pneumonia and diarrhoea—Tackling the deadliest diseases for the world's poorest children, which revealed that less than 29% of the worlds' children with potential pneumonia receive antibiotics for their illness (5). In an attempt to improve access to essential medicines in countries with weak health systems, strategies for managing pneumonia in the community are recommended (6). These strategies typically use trained community health workers (CHWs) to assess, classify, and treat children using antibiotic and antimalarial drugs. While community case management (CCM) of malaria and pneumonia can reduce mortality (7,8) there is a concern that CHWs' performance is poorer when they are required to manage several illnesses and that over-treatment and antibiotic resistance in bacteria could be negative consequences of these programmes (9). Antibiotic Resistance in Preschool Children Assignment. The worldwide incidence of infections caused by pneumococci resistant to penicillin and other antimicrobial agents has increased at an alarming rate during past decades (10). Resistance is believed to be driven by antibiotic use (both appropriate and inappropriate), dose, and duration of therapy (11). The use of broad-spectrum antibiotics, as a substitute for precise diagnosis or to enhance the likelihood of treatment success, and use of sub-standard medicines, which give sub-optimal blood drug concentrations, enhance the selection rate of resistant bacteria (12). While prophylactic use of trimethoprimsulphamethoxazole (TMP-SMX, or co-trimoxazole) to prevent opportunistic infections in HIV+ patients is policy in several sub-Saharan countries, many of these countries are also using co-trimoxazole as firstline treatment for non-severe pneumonia. A major factor in the pathogenesis of pneumococcal disease, its transmission, and spread of drug resistance is the nasopharyngeal reservoir of bacteria which is carried by up to 60%–70% of healthy children (13). The colonizing strains, which are carried for a mean duration of 6 weeks, can easily spread from one child to another (14), and their characteristics and susceptibility patterns have been shown to be similar to those involved in invasive illness (15). Hence, studies of the nasopharyngeal reservoir of bacteria can provide useful information about the prevalence and resistance patterns of respiratory pathogens in a population, and how these characteristics change over time. High rates of in vitro resistance to antibiotics have been found in nasopharyngeal isolates in both Gram-positive (e.g. Streptococcus pneumoniae) and Gram-negative (e.g. Haemophilus influenzae and Moraxella catarrhalis) respiratory organisms (16,17). Antibiotic Resistance in Preschool Children Assignment. We were unable to find any population-based study of nasopharyngeal carriage and resistance in respiratory pathogens in Uganda. Hence, our objective was to establish the bacterial composition of nasopharyngeal flora and its in vitro resistance in healthy children at the community level. The study was carried out as a baseline before the introduction of integrated community case management of fever using amoxicillin for presumptive pneumonia and artemether–lumefantrine (Coartem) for presumptive malaria. Materials and methods A cross-sectional survey of nasopharyngeal carriage among healthy children under five was conducted in the Iganga/Mayuge Health and Demographic Surveillance Site (HDSS) in Eastern Uganda in April 2008. The HDSS follows standard INDEPTH network methodology (18) and keeps a census of 65,000 people living in a geographically defined area totalling 3931 km2 . A sample of 152 households with children younger than 5 years of age was selected from the HDSS population register using simple random sampling. Each of the selected households was visited, and one child aged between 2 and 59 months was selected using a lottery method. The primary caretaker was interviewed using a pretested questionnaire for information on socio-demographic characteristics, illness symptoms, and treatments in the last 2 weeks. The household identifier was linked to the HDSS database for retrieval of household characteristics such as crowding, water source, and number of children 5 years. With caretaker consent a nasopharyngeal specimen was collected by a lab technician in each of the 152 children. Pre-packed sterile calcium alginate swabs on flexible aluminium shafts (BD, Franklin Lakes, New Jersey, USA) were used. The swabs were placed in Amies transport medium in a tube. Tubes were transported within 12 h to the Microbiology lab at Makerere University Medical School. Each sample was registered in a book, where date of receipt, lab number, and household number were entered. Each swab was streaked within 3 h on blood agar plates supplemented with 7% sheep blood as well as on chocolate agar. An optochin disk was placed in the first streak area, and plates were incubated at 37C in 5%–10% CO2 for 24–48 h. S. pneumoniae was identified by an inhibition zone 250 E. Rutebemberwa et al. around the optochin disk and the presence of a-haemolytic, flat, irregularly shaped colonies with central depression with maturity. H. influenzae was identified by morphology (convex, smooth, pale, grey, or transparent) and with oxidase test, Gram stain, satellitism, and growth dependence on factors X and V. M. catarrhalis isolates were identified using standard microbiological methods: colony morphology (grey-white hemispheric colonies about 1 mm in diameter), Gram stain, oxidase test, DNase production, and a nitrate reduction test. S. pneumoniae colonies from a 24-h-old subculture were suspended in sterile normal saline to achieve a density equal to a 0.5 McFarland standard. The inoculum was swabbed onto three plates of Mueller– Hinton agar supplemented with 7% sheep blood. Antimicrobial susceptibility to penicillin (1 mg oxacillin disc was used), erythromycin (15 mg), and TMPSMX (co-trimoxazole) (1.25/23.75 mg) was determined by disk diffusion (Biolab Inc., Budapest, Hungary). Streptococcus pneumoniae ATCC 6303 was used as control, and results were within acceptable ranges. Minimum inhibitory concentration (MIC) of penicillin for S. pneumoniae was determined using E test (bioMe´rieux, Marcy l'Etoile, France). Antibiotic discs or E test strips were placed on the swabbed plates, which were then incubated for 24 h at 37C in 5% CO2.Antibiotic Resistance in Preschool Children Assignment. Zone diameters and MIC of various antibiotics were read and interpreted using Clinical and Laboratory Standards Institute guidelines (19). The disk diffusion interpretation is shown in Table I. H. influenzae was only analysed for detection of b-lactamase activity, determined by the chromogenic cephalosporin nitrocefin (BR66A; Oxoid Limited, Basingstoke, United Kingdom) method using known b-lactamase positives as controls. The study protocol was reviewed by the Institutional Review Board at Makerere University School of Public Health, and ethical approval was obtained from Uganda National Council for Science and Technology (Ref HS 72). Verbal consent was obtained from district and village leaders as well as from caretakers while the studied children gave assent. Antibiotic Resistance in Preschool Children Assignment. Results Descriptive statistics The median age of the 152 children was 24 months (Interquartile Range (IQ) 12–33.5). Fifty-two per cent of the children were girls (Table II). Complete socio-demographic profile was available for 82.9% (126/152) of the included children, of whom 82.1% were from rural villages and 73.6% used spring water as their primary water source. The median number of children less than 5 years of age per household was 2 (IQ 1–2), and the median number of household members per bedroom (as a measure of crowding) was 4 (IQ 3–5). Antibiotic Resistance in Preschool Children Assignment. Table II. Socio-demographic characteristics of the household heads, caretakers, and children. Variable Number of children (%) Child age 2 years 77 (50.7) 42 years 75 (49.3) All 152 (100) Child sex Girl 79 (52.0) Boy 73 (48.0) All 152 (100) Residence Rural 110 (82.1) Urban 24 (17.9) All 134 (100) Water source Spring water 95 (73.6) Well water 33 (25.6) Piped water 1 (0.8) All 126 (100) Number of children under 5 in household 1 70 (49.3) 2 54 (38.0) 3 11 (7.8) 4 6 (4.2) 6 1 (0.7) All 142 (100) Number of people per bedroom 0–2 13 (10.3) 3–5 84 (66.1) 5+ 30 (23.6) All 127 (100) Table I. Disk diffusion interpretation. Zone diameter interpretation (mm) Agent Disk content/mL Susceptible Intermediate Resistant Oxacillin 1 mg oxacillin 20 a a Trimethoprim-sulphamethoxazole 1.25/23.75 mg 19 16–18 15 Erythromycin 15 mg 21 – 20 a If the zone diameter for oxacillin is520 mm, an isolate cannot be reported as susceptible, intermediate, or resistant, and MIC testing must be conducted for an appropriate penicillin (or other b-lactam) drug (19). Antibiotic Resistance in Preschool Children Assignment. Carriage of resistant bacteria in Uganda 251 Illness and antibiotic use in the previous 2 weeks According to reports of the mothers, 95% (145/152) of the children had been sick in the previous 2 weeks. Among these, the most common symptoms were fever (91.7%; 133/145), running nose (61.4%; 89/145), and cough (44.8%; 65/145). No child was reported to have had fast breathing. Of the children who had been sick, 27.6% (40/145) had reportedly been given an antibiotic, mostly co-trimoxazole (77.5%; 31/40) and ampicillin (12.5%; 5/40). Only one child had been given amoxicillin. Antibiotics were given to 29.2% (19/65) of children with cough, 27.3% (24/88; 1 observation missing) of those with running nose, and 26.3% (35/131; 2 observations missing) of those with fever. Nasopharyngeal carriage S. pneumoniae was recovered from 58.6% (89/152) of the children, M. catarrhalis from 15% (23/152), and H. influenzae from 11% (16/152). Of all children sampled 34% (52/152) had none of the three bacteria, 20% (30/152) had two of the three bacteria (16 had M. catarrhalis + S. pneumonia, and 14 had H. influenzae + S. pneumonia). No child had all three bacteria. There was no difference in pneumococcal carriage between boys and girls, between children 6 months versus older children, bedroom crowding, or number of under-5 children in the household. Antibiotic Resistance in Preschool Children Assignment. Antimicrobial susceptibility Of the pneumococcal isolates 98.9% (88/89) were resistant to co-trimoxazole, and 80.9% (72/89) had intermediate resistance to penicillin. None was highly resistant to penicillin (2 mg/mL) (Table III). Sex, previous illness symptoms, treatment taken, and socio-economic or household profile had no effect on carriage of non-susceptible or intermediately resistant S. pneumoniae. Of the 16 H. influenzae isolates, 4 (25%) were producing b-lactamase. Discussion This study, which is one of the first population-based studies from East Africa that determines both the bacterial composition of the nasopharyngeal flora and its in vitro resistance in healthy children at the community level, shows colonization rates of 59% for S. pneumonia, 15.1% for M. catarrhalis, and 10.5% for H. influenzae. The S. pneumoniae colonization rate has been shown to vary geographically. While the 59% carriage rate found in our study is consistent with the 51%–60% prevalence found in coastal Kenya (20), it is much lower than the 97% observed in Gambian infants (21). Other studies from children in hospital settings in southern Africa generally show higher carriage rates (469%) (22,23). Apart from differences in sampling frames, other factors influencing nasopharyngeal carriage rates include age, season, number of siblings, and acute respiratory illness (24). Our study did not show any significant association between pneumococcal carriage and these known risk factors, probably due to the small sample size. Antibiotic Resistance in Preschool Children Assignment. Almost all pneumococcal strains were resistant in vitro to the treatment that was first line for pneumonia at the time of the study, co-trimoxazole, and 81% had intermediate resistance to penicillin. No isolate had high resistance to penicillin (2.0 mg/mL). Nevertheless, the 99% co-trimoxazole resistance is very high, and similar levels have only been observed in one other study, also from Uganda but in an adult population (25). Previous studies on pneumococcal isolates showed that co-trimoxazole resistance varied depending on sampling frame: from 39% in healthy village children in the Gambia (21), 83.5% in healthy children in a Ugandan hospital (26), and 64% in patients with invasive disease in South Africa (27). Yet the extreme levels of pneumococci resistant to co-trimoxazole reported Table III. Antimicrobial susceptibility of isolated respiratory pathogens, n ¼ 89 (%). Agent Bacterium Susceptible Intermediate Resistant Oxacillina S. pneumoniae 17 (19.1) c c Nitrocefinb Moraxella sp. 2 (9.5) – 19 (90.5) Haemophilus sp. 12 (75.0) 4 (25.0) Trimethoprim-sulphamethoxazolea S. pneumoniae 1 (1.1) 0 88 (98.9) Erythromycina S. pneumoniae 89 (100) – 0 Penicillinb S. pneumoniae 17 (19.1) 72 (80.9) 0 a Determined by disk diffusion. b Determined by E test. c If the zone diameter for oxacillin is520 mm, an isolate cannot be reported as susceptible, intermediate, or resistant, and MIC testing must be conducted for an appropriate penicillin (or other b-lactam) drug (19). 252 E. Rutebemberwa et al. from studies in Uganda have not been observed in any other country. While the result of the susceptibility testing indicates a very homogeneous susceptibility pattern, a clonal spread could be suspected. However, the study area is large, and it is unlikely that the children sampled lived very close to each other or would ever have met. The molecular characteristics of pneumococci in healthy carriers and cases with invasive disease need to be determined to explain further the transmission and the high prevalence of non-susceptible bacteria in the study area. Antibiotic Resistance in Preschool Children Assignment. Penicillin resistance patterns also vary greatly between countries (0%–79%), and it is well documented that resistance in pneumococci is increasing globally (16). Most studies on carriage of resistant pneumococci are conducted on hospital-based samples, such as another Uganda study which found 83.5% intermediate penicillin resistance (26). Of the few population-based studies from sub-Saharan Africa that were identified, intermediate penicillin resistance ranged from 14% in village-based infants in the Gambia (21,28), 45% in children in urban Ghanaian kindergartens (29), to 67% in healthy Tanzanian children attending an urban clinic (30). Again, it appears that Uganda, where we found 80% intermediate penicillin resistance, is on the higher end of the global penicillin-non-susceptible S. pneumoniae spectrum. Despite these remarkable in vitro resistance rates of S. pneumoniae in the nasopharyngeal flora, the clinical relevance of these findings has not been clearly established. While there is evidence of the inferiority of co-trimoxazole in vivo efficacy in treating pneumonia (31), most studies have not been able to show any consistent association between in vitro resistance to co-trimoxazole and failure of therapy in cases of non-severe pneumonia (32). Studies that documented impact of b-lactam resistance on pneumococcal pneumonia mortality (33,34) had not been adjusted for severity of disease or HIV infection (35). In addition, susceptibility is rarely determined in community settings, but data primarily come from hospitalized patients where aggressive intravenous and/or multi-drug therapy makes the impact of therapy difficult to assess (11). Antibiotic Resistance in Preschool Children Assignment. In 2009 the World Health Organization (WHO) recommended that while co-trimoxazole may be an alternative in some settings, national treatment policies should change to amoxicillin as first-line treatment of children 2–59 months of age diagnosed with pneumonia (36,37). Yet, despite the widespread pneumococcal in vitro resistance to co-trimoxazole, the treatment is still used as a first choice for treatment of pneumonia in many countries, primarily due to its low cost, few side effects, and because it can be safely used by health workers at the peripheral health facilities and at home by mothers (31). While agencies like UNICEF and WHO recommend that 'the clinical efficacy of pneumonia treatment should be monitored regularly to revise national treatment policies based on antimicrobial resistance information, clinical outcomes and other data' (38), such surveillance has been sporadic in most of subSaharan Africa. Hence, more studies on how in vitro resistance in pneumococci translates into clinical outcomes in patients with varying treatment regimens and disease severity are urgently needed to optimize the clinical management of pneumonia (11,35). Meanwhile, monitoring of the bacterial reservoir in the society over time can provide important information on the characteristics and spread of respiratory bacteria, especially in relation to interventions such as community case management and introduction of vaccines against respiratory pathogens. Antibiotic Resistance in Preschool Children Assignment. The most important factor driving resistance is previous exposure to antibiotics (24,35). In our study one-third of children in the community had been given an antibiotic in the previous 2 weeks. Since a child in this context is expected to suffer from 0.3 episodes of pneumonia per year (39) it is apparent that over-treatment with antibiotics is common. The WHO case management guidelines (40,41), which are based on simple clinical signs to help health workers identify and appropriately manage pneumonia and other illnesses in the community and health facilities, have shown to increase rational prescribing of medicines (42). However, as WHO guidelines do not make a distinction between viral and bacterial pneumonia, these children continue to receive antibiotics because of the concern that it may not be safe to do otherwise. Hence, studies on how to reduce unnecessary prescribing, not only in health facilities but also at the community level and in the private sector, are key to preserve the efficacy of existing antibiotics. There is a need for simple methodologies to help health workers collect relevant data that can inform decision-makers to change policy and guidelines from first- to second-line antibiotics (43). Scaling up the pneumococcal vaccine (PCV) for children is a potential strategy to reduce the incidence of pneumococcal disease and possibly also reduce the problem with resistant strains among PCV serotypes. However, the actual role of the PCV in relation to pneumococcal resistance development is not yet fully understood, and it is likely that pneumococcal vaccine pressure has led to the selection of resistance in non-vaccine pneumococcal serotypes (44); this Carriage of resistant bacteria in Uganda 253 calls for research on a vaccine that targets the antibiotic resistance mechanism itself (45). Research is also warranted to identify inexpensive and efficacious alternative antibiotic regimens that are associated with good adherence such as through co-formulated combination therapy, less frequent dosing, and shorter courses. More specific diagnostic criteria for acute respiratory infection and improved diagnostic tests should be developed and evaluated in clinical practice. Antibiotic Resistance in Preschool Children Assignment. There are some methodological limitations of this study to keep in mind. The very high prevalence of reported illness is likely a result of caretaker overreporting, and as a consequence illness data should be interpreted with caution. It is possible that the study purpose was not explained sufficiently well, leading caretakers to give answers which she or he expected to be 'desired' by the interviewer (46). This study was also based on a small study sample, which did not allow for stratified analysis. While we were unable to type the pneumococcal isolates for serotypes and clones, data on serotypes and resistance patterns from the same study population have been collected at a later stage and will be published elsewhere (Lindstrand et al., unpublished). Because the intention of the study was to have a baseline estimate of nasopharyngeal carriage and resistance rates in the child population before rollout of blisterpacked amoxicillin through community health workers, the funding did not allow for these molecular analyses. We would like to conclude that among the pneumococci isolated from healthy children in the community, in vitro resistance to co-trimoxazole treatment was high, and the majority of strains had intermediate resistance to penicillin. To inform treatment policies on the clinical efficacy of current treatment protocols for pneumonia in facilities and at the community level, routine surveillance of resistance in pneumonia pathogens is needed as well as rigorous research on the association between pneumococcal in vitro resistance in populationbased samples and in vivo efficacy of treatment of clinical pneumonia. The revised WHO treatment guidelines for pneumonia in children, which recommend the use of amoxicillin over co-trimoxazole, should be rolled out widely. Pneumococcal vaccination should be scaled up, and improved clinical algorithms and diagnostics for pneumonia should be developed. Acknowledgements E.R. participated in the design of the study, supervised the data collection in the field, and helped to draft the manuscript. B.M., G.P., S.P., and E.M. were part of conceiving the study, participated in the design, and helped to draft the manuscript. F.B. carried out the analysis in the laboratory and helped draft the manuscript. K.K. was part of conceiving the study, participated in the design, helped in the data collection in the field, performed the statistical analysis, and drafted the manuscript. All authors read and approved the final manuscript. Antibiotic Resistance in Preschool Children Assignment. We thank all the children and caretakers who agreed to participate in the study. We also thank the HDSS field workers and staff for managing data collection, compilation, and entering. We are grateful to the laboratory assistants in the Makerere University Department of Microbiology for analysing the specimens and to INDEPTH for technical support. 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