Online-Only Abstracts

Urosepsis is a bacteraemia infection caused by an organism previously causing an infection in the urinary tract of a patient, a diagnosis which has been classically confirmed by culture of the same species of bacteria from both blood and urine samples. Given the new insights afforded by sequencing technologies into the complicated population structures of infectious agents affecting humans, we sought to investigate urosepsis by comparing the genome sequences of blood and urine isolates of Escherichia coli from five patients with urosepsis. The results confirm the classical urosepsis hypothesis in four of the five cases, but also show the complex nature of extra-intestinal E. coli infection in the fifth case, where three distinct strains caused two distinct infections. Additionally, we show there is little to no variation in the bacterial genome as it progressed from urine to blood, and also present a minimal set of virulence genes required for bacteraemia in E. coli based on gene association. These suggest that most E. coli have the genetic propensity to cause bacteraemia.Effects of amoxicillin treatment on the salivary microbiota in children with acute otitis mediaV. Lazarevic¹S. Manzano²N. Gaía¹M. Girard¹K. Whiteson¹J. Hibbs¹P. François¹A. Gervaix²J. Schrenzel¹1) Division of Infectious Diseases, Genomic Research Laboratory, Geneva University Hospitals and 2) Division of Paediatric Emergency Medicine, Department of Child and Adolescent Medicine, Geneva University Hospitals, Geneva, SwitzerlandOriginal Submission: 22 October 2012; Revised Submission: 1 February 2013; Accepted: 2 March 2013 Editor: G. GreubArticle published online: 14 March 2013Clin Microbiol Infect 2013; 19: E335–E34210.1111/1469-0691.12213

Abstract

Amoxicillin is a first-line antibiotic treatment for acute otitis media in children and one of the most commonly used antibiotics for human bacterial infections. We investigated changes in salivary bacterial communities among children treated with amoxicillin for acute otitis media (n = 18), using a culture-independent approach based on pyrosequencing of the V3 region of the bacterial 16S rRNA gene. The control group consisted of children with acute otitis media who were not given antibiotics (n = 15). One species-level phylotype assigned to the genus Streptococcus was identified across all (n = 99) saliva samples. Two additional species-level phylotypes from the genera Gemella and Granulicatella were shared by all (n = 45) samples of control subjects. Amoxicillin treatment resulted in reduced species richness and diversity, and a significant shift in the relative abundance of 35 taxa at different ranks from phylum to species-level phylotype. At the phylum level, prevalence of TM7 and Actinobacteria decreased at the end of treatment, whereas Proteobacteria had a higher relative abundance post-treatment. Multivariate analysis showed that samples from the same control subject taken over time intervals tended to cluster together. Among antibiotic-treated subjects, samples taken before and at the end of amoxicillin treatment formed two relatively well-separated clusters both of which greatly overlapped with samples taken about 3 weeks post-treatment. Our results point to a substantial but incomplete recovery of the salivary bacterial community from the antibiotic about 3 weeks after the end of treatment.     

Amoxicillin for acute lower respiratory tract infection in primary care: subgroup analysis by bacterial and viral aetiology

ObjectiveWe aimed to assess the effects of amoxicillin treatment in adult patients presenting to primary care with a lower respiratory tract infection (LRTI) who were infected with a potential bacterial, viral, or mixed bacterial/viral infection.MethodsThis multicentre randomized controlled trial focused on adults with LRTI not suspected for pneumonia. Patients were randomized to receive either antibiotic (amoxicillin 1 g) or placebo three times daily for 7 consecutive days using computer-generated random numbers (follow-up 28 days). In this secondary analysis of the trial, symptom duration (primary outcome), symptom severity (scored 0–6), and illness deterioration (reconsultation with new or worsening symptoms, or hospital admission) were analysed in pre-specified subgroups using regression models. Subgroups of interest were patients with a (strictly) bacterial, (strictly) viral, or combined infection, and patients with elevated values of procalcitonin, C-reactive protein, or blood urea nitrogen.Results2058 patients (amoxicillin n = 1036; placebo n = 1022) were randomized. Treatment did not affect symptom duration (n = 1793). Patients from whom a bacterial pathogen only was isolated (n = 207) benefited from amoxicillin in that symptom severity (n = 804) was reduced by 0.26 points (95% CI −0.48 to −0.03). The odds of illness deterioration (n = 2024) was 0.24 (95% CI 0.11 to 0.53) times lower from treatment with amoxicillin when both a bacterial and a viral pathogen were isolated (combined infection; n = 198).ConclusionsAmoxicillin may reduce the risk of illness deterioration in patients with a combined bacterial and viral infection. We found no clinically meaningful benefit from amoxicillin treatment in other subgroups.     

Multicenter, randomized, double-blind comparison of erythromycin estolate versus amoxicillin for the treatment of acute otitis media in children

Erythromycin is frequently prescribed in Germany for acute otitis media, but well-designed clinical trials under present epidemiological conditions are lacking. Therefore, a double-blind, randomized, multicenter trial was performed to compare the clinical efficacy and safety of erythromycin estolate versus amoxicillin in children with acute otitis media and to identify the risk factors associated with clinical failure. Investigators from 19 centers throughout Germany recruited 302 children with clinical, otoscopic, and tympanometric evidence of acute otitis media. In a double-blind fashion, patients were allocated randomly to a 10-day course of erythromycin estolate at 40 mg/kg/day in two divided doses or amoxicillin at 50 mg/kg/day in two divided doses. Clinical examinations, otoscopy, and tympanometry were performed at baseline, day 3–5, day 9–11, and at 5 weeks. Clinical outcome was assessed on day 9–11. Two-hundred eighty children were evaluable for efficacy (erythromycin group, 141; amoxicillin group, 139). Both groups were comparable with respect to demographic data and severity of disease at entry. Treatment was successful in 94% of the erythromycin-treated patients and in 96% of the amoxicillin-treated patients. Clinical outcome was statistically equivalent between groups within a range of 7 percentage points. Clinical recurrence was seen in eight erythromycin-treated children (5.7%) and in seven amoxicillin-treated children (5.0%) (P=0.81). Patients with bilateral disease at entry were at higher risk of unfavourable outcome, whereas age and presence/absence of otorrhea at entry were not associated with outcome. Treatment-related adverse events were recorded in eight (5.3%) of 151 erythromycin-treated patients and in 11 (7.3%) of 151 amoxicillin-treated patients. In this study in an outpatient setting in Germany, erythromycin estolate was as safe and effective as amoxicillin in the treatment of acute otitis media. Both drugs can be administered in a convenient twice-daily dosage schedule.     

Ear discharge in children presenting with acute otitis media: observational study from UK general practice

Background

National Institute for Health and Clinical Excellence (NICE) guidance to treat otitis media in older children immediately with antibiotics only if they have ear discharge is based on limited evidence.

Aim

To determine the clinical significance and outcome of ear discharge in children with acute otitis media, in routine clinical practice.

Design of study

Observational cohort study of children with acute otitis media comparing those with and without ear discharge at presentation.

Setting

Primary care in East Somerset.

Method

Two hundred and fifty-six children aged 6 months to 10 years were recruited from primary care. Clinical features and other characteristics were recorded at presentation. Follow-up was undertaken at 2 weeks and 3 months.

Results

Children with otitis media who present with ear discharge are much more likely to be treated with antibiotics irrespective of age (adjusted odds ratio 15, 95% confidence interval [CI] = 3 to 66). Most with discharge have proven bacterial infection (58%, 95% CI = 42 to 72%). They have a more severe systemic illness, with higher axillary temperature (80% increase in odds of ear discharge for each additional degree centigrade, P = 0.02), pulse rate (9% increase in odds for each extra beat, P<0.001), and Yale score (mean 10.5 versus 9.0, P = 0.003). They may also have an increased likelihood of adverse outcome (adjusted odds ratio of pain at 1 week 2.9; further episodes of acute otitis media 3.3; hearing difficulty at 3 months 4.7; all P<0.10).

Conclusion

Ear discharge defines a group of children with otitis media who are sicker and may be at higher risk of adverse outcome. NICE guidance to treat them with antibiotics is supported.     

Multicentre comparative study of the efficacy and safety of azithromycin compared with amoxicillin/clavulanic acid in the treatment of paediatric patients with otitis media

An open multicentre study was conducted in 484 children between the ages of 6 months and 12 years with otitis media to compare the efficacy, the safety and the tolerance of once-daily azithromycin given for three days versus thrice-daily amoxicillin/clavulanic acid (CA) given for ten days. A satisfactory response (cure plus improvement) was noted 10 to 14 days after the start of treatment in 199 of 215 (92.6 %) azithromycin-treated children and in 186 of 198 (93.9 %) amoxicillin/CA-treated children. The relationship between treatment and clinical response was independent of chronicity of infection and the presence or absence of a perforated eardrum. Improvement in signs and symptoms of otitis media occurred significantly more rapidly in the children treated with azithromycin. Treatment-related or possibly treatment-related adverse events were recorded in 11 of 243 (4.5 %) azithromycin-treated patients and in 20 of 240 (8.3 %) treated with amoxicillin/CA. No patients in the azithromycin treatment group were withdrawn from treatment, but six amoxicillin/CA patients, including two < 2 years of age, discontinued treatment prematurely because of adverse events; the difference between treatment groups was statistically significant (p=0.0146). It is concluded that azithromycin given as an oral suspension once daily for three days is as safe and effective as amoxicillin/CA given thrice daily for ten days in the treatment of children with otitis media.     

Acute Mastoiditis in the Pneumococcal Conjugate Vaccine Era

Following the introduction of the 7- and 13-valent pneumococcal conjugate vaccines, we observed an inverse relationship between the increasing rate of immunized children and the proportion of middle ear fluid cultures collected during acute mastoiditis episodes that tested positive for Streptococcus pneumoniae among a subset of children 0 to 6 years old who had initially presented with severe acute otitis media and had bacterial cultures collected during tympanocentesis or from spontaneous otorrhea.     

Otitis media among high-risk populations: can probiotics inhibit Streptococcus pneumoniae colonisation and the risk of disease?

Otitis media is the second most common infection in children and the leading cause for seeking medical advice. Indigenous populations such as the Inuits, indigenous Australians and American Indians have a very high prevalence of otitis media and are considered to be high-risk populations. Streptococcus pneumoniae, one of the three main bacterial causes of otitis media, colonises the nasopharynx prior to disease development. In high-risk populations, early acquisition of high bacterial loads increases the prevalence of otitis media. In these settings, current treatment strategies are insufficient. Vaccination is effective against invasive pneumococcal infection but has a limited impact on otitis media. Decreasing the bacterial loads of otitis media pathogens and/or colonising the nasopharynx with beneficial bacteria may reduce the prevalence of otitis media. Probiotics are live microorganisms that offer health benefits by modulating the microbial community and enhancing host immunity. The available data suggest that probiotics may be beneficial in otitis media. This review discusses the potential use of probiotics to reduce pathogen colonisation and decrease the prevalence of otitis media, providing justification for further investigation.     

Nasopharyngeal flora and acute otitis media.

A semiquantitative nasopharyngeal culture was found to be sensitive and specific in predicting middle ear pathogens in children with acute bacterial otitis media. In nasopharyngeal specimens with growth of at least 1,000 colonies, the tympanocentesis isolate was present and was either the predominant isolate or accounted for 50% of growth in 16 of 16 children. Data suggest that virulence of nasopharyngeal organisms plays a role in the pathogenesis of acute otitis media. Qualitative differences were found in the nasopharyngeal flora of children with bacterial otitis media as compared with children with clinical otitis media and sterile tympanocentesis cultures, children with uncomplicated upper respiratory illness, and healthy children. Abundant growth of Haemophilus influenzae (greater than or equal to 50% total colony count) was associated with children with bacterial otitis media, and abundant Branhamella catarrhalis was associated with the others (P less than or equal to 0.01). Abundant growth of Streptococcus pneumoniae occurred frequently and regardless of clinical category. Antibiotic treatment of children with otitis media resulted in rapid quantitative and qualitative changes in nasopharyngeal flora.     

Comparison of amoxicillin with second and third generation cephalosporins in the treatment of acute otitis media

The aim of the present study was to compare the efficacy and the tolerability of three different antibiotic regimens for the treatment of acute otitis media in paediatric patients. 75 children, age range 6 months-6 years, divided into three groups, were involved in the study, each group consisting of 25 randomly assigned children (Group 1, amoxicillin 40 mg/kg tid per os for 10 days; Group 2, cefuroxime axetil 30 mg/kg bid per os for 10 days; ceftriaxone 50 mg/kg single-dose i.m.). No statistically significant difference was noted in the clinical efficacy among the different groups. Although amoxicillin is the drug of choice in paediatric otitis media, single dose ceftriaxone might be considered as an interesting alternative regimen when ease of administration and cost of therapy are considered.     

Viral-bacterial interactions and risk of acute otitis media complicating upper respiratory tract infection

Acute otitis media (AOM) is a common complication of upper respiratory tract infection whose pathogenesis involves both viruses and bacteria. We examined risks of acute otitis media associated with specific combinations of respiratory viruses and acute otitis media bacterial pathogens. Data were from a prospective study of children ages 6 to 36 months and included viral and bacterial culture and quantitative PCR for respiratory syncytial virus (RSV), human bocavirus, and human metapneumovirus. Repeated-measure logistic regression was used to assess the relationship between specific viruses, bacteria, and the risk of acute otitis media complicating upper respiratory tract infection. In unadjusted analyses of data from 194 children, adenovirus, bocavirus, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis were significantly associated with AOM (P < 0.05 by χ(2) test). Children with high respiratory syncytial virus loads (≥3.16 × 10(7) copies/ml) experienced increased acute otitis media risk. Higher viral loads of bocavirus and metapneumovirus were not significantly associated with acute otitis media. In adjusted models controlling for the presence of key viruses, bacteria, and acute otitis media risk factors, acute otitis media risk was independently associated with high RSV viral load with Streptococcus pneumoniae (odds ratio [OR], 4.40; 95% confidence interval [CI], 1.90 and 10.19) and Haemophilus influenzae (OR, 2.04; 95% CI, 1.38 and 3.02). The risk was higher for the presence of bocavirus and H. influenzae together (OR, 3.61; 95% CI, 1.90 and 6.86). Acute otitis media risk differs by the specific viruses and bacteria involved. Acute otitis media prevention efforts should consider methods for reducing infections caused by respiratory syncytial virus, bocavirus, and adenovirus in addition to acute otitis media bacterial pathogens.     

Efficacy of amoxicillin with and without decongestant-antihistamine for otitis media with effusion in children. Results of a double-blind, randomized trial

In a randomized, double-blind, placebo-controlled trial involving 518 infants and children who had otitis media with effusion ("secretory" otitis media), we evaluated the efficacy of a two-week course of amoxicillin (40 mg per kilogram of body weight per day) with and without a four-week course of an oral decongestant-antihistamine combination. Among the 474 subjects who were evaluated at the four-week end point, the rate of resolution of middle-ear effusion was twice as high in those treated with amoxicillin, either with or without the decongestant-antihistamine, as in those who received placebo (P less than 0.001), but 69.8 percent of the amoxicillin-treated subjects still had effusion. Among both the amoxicillin-treated subjects and the placebo-treated subjects, resolution was more likely in those with initially unilateral effusion, in those who had had effusion for eight weeks or less, and in those without an upper respiratory tract infection at the four-week end point. Side effects were reported more often in subjects who received decongestant-antihistamine than in those who did not. Among the subjects without effusion at the four-week end point, recurrent effusion developed in approximately half those in both the amoxicillin and placebo groups during the subsequent three months. We conclude that in infants and children with otitis media with effusion, amoxicillin treatment increases to some extent the likelihood of resolution.     

阿奇霉素对比阿莫西林/克拉维酸治疗儿童急性中耳炎疗效和安全性的Meta分析

目的采用Meta分析方法比较阿奇霉素与阿莫西林／克拉维酸治疗儿童急性中耳炎疗效和安全性。方法电子检索中国生物医学文献数据库、中文科技期刊数据库、中国知网、万方数据库、中国医学会数字化期刊、PubMed、Cochrane Library和EMBASE数据库,检索起止时间均从建库至2013年8月。纳入阿奇霉素对比阿莫西林／克拉维酸治疗儿童急性中耳炎的RCT文献,对文献进行质量评价。评估临床治愈率、治疗失败率和不良反应。采用RevMan5．0软件进行数据分析,二分类变量采用OR及其95％CI表示。结果共纳入13篇RCT文献（5081例患儿）。Meta分析结果显示,阿奇霉素组与阿莫西St,／克拉维酸组在〈10d临床治愈率（OR=0．69,95％CI：0．46～1．02）、-19d临床治愈率（OR=0．88,95％CI：0．68～1．13）、～29d临床治愈率（OR=0．99,95％CI：0．83—1．19）、t〉30d临床治愈率（OR=1．00,95％CI：0．72～1．39）和治疗失败率（OR=0．87,95％CI：0．65～1．17）差异均无统计学意义。阿奇霉素组恶心（OR=0．44,95％CI：0．20～0．97）、皮疹（OR=0．48,95％CI：0．31～0．75）、腹泻（OR=0．38,95％CI：0．25～0．57）和稀便（OR=0．41,95％CI：0．20—0．81）的发生率显著低于阿莫西林／克拉维酸组。结论阿奇霉素与阿莫西林／克拉维酸治疗儿童中耳炎疗效相当且不良反应少。     

Bacterial coinfections in children with viral wheezing

Bacterial coinfections occur in respiratory viral infections, but the attack rates and the clinical profile are not clear. The aim of this study was to determine bacterial coinfections in children hospitalized for acute expiratory wheezing with defined viral etiology. A total of 220 children aged 3 months to 16 years were investigated. The viral etiology of wheezing was confirmed by viral culture, antigen detection, serologic investigation, and/or PCR. Specific antibodies to common respiratory bacteria were measured from acute and convalescent serum samples. All children were examined clinically for acute otitis media, and subgroups of children were examined radiologically for sinusitis and pneumonia. Rhinovirus (32%), respiratory syncytial virus (31%), and enteroviruses (31%) were the most common causative viruses. Serologic evidence of bacterial coinfection was found in 18% of the children. Streptococcus pneumoniae (8%) and Mycoplasma pneumoniae (5%) were the most common causative bacteria. Acute otitis media was diagnosed in 44% of the children. Chest radiographs showed alveolar infiltrates in 10%, and paranasal radiographs and clinical signs showed sinusitis in 17% of the older children studied. Leukocyte counts and serum C-reactive protein levels were low in a great majority of patients. Viral lower respiratory tract infection in children is often associated with bacterial-type upper respiratory tract infections. However, coexisting bacterial lower respiratory tract infections that induce systemic inflammatory response are seldom detected.     

High detection rates of nucleic acids of a wide range of respiratory viruses in the nasopharynx and the middle ear of children with a history of recurrent acute otitis media

Both bacteria and viruses play a role in the development of acute otitis media, however, the importance of specific viruses is unclear. In this study molecular methods were used to determine the presence of nucleic acids of human rhinoviruses (HRV; types A, B, and C), respiratory syncytial viruses (RSV; types A and B), bocavirus (HBoV), adenovirus, enterovirus, coronaviruses (229E, HKU1, NL63, and OC43), influenza viruses (types A, B, and C), parainfluenza viruses (types 1, 2, 3, 4A, and 4B), human metapneumovirus, and polyomaviruses (KI and WU) in the nasopharynx of children between 6 and 36 months of age either with (n = 180) or without (n = 66) a history of recurrent acute otitis media and in 238 middle ear effusion samples collected from 143 children with recurrent acute otitis media. The co-detection of these viruses with Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis was analyzed. HRV (58.3% vs. 42.4%), HBoV (52.2% vs. 19.7%), polyomaviruses (36.1% vs. 15.2%), parainfluenza viruses (29.4% vs. 9.1%), adenovirus (25.0% vs. 6.1%), and RSV (27.8% vs. 9.1%) were detected significantly more often in the nasopharynx of children with a history of recurrent acute otitis media compared to healthy children. HRV was predominant in the middle ear and detected in middle ear effusion of 46% of children. Since respiratory viruses were detected frequently in the nasopharynx of both children with and without a history of recurrent acute otitis media, the etiological role of specific viruses in recurrent acute otitis media remains uncertain, however, anti-viral therapies may be beneficial in future treatment and prevention strategies for acute otitis media.     

Serum concentrations of amoxicillin in neonates during continuous intravenous infusion

Amoxicillin is commonly used for the treatment of neonatal bacterial infection with intermittent dosing (ID) regimens. However, increasing bacterial resistance, in addition to a lack of new antimicrobial agents, urges the optimization of current therapeutic options. Clinical studies in adults suggest continuous infusion (CI) regimens of beta-lactam antibiotics to be superior to ID. There are as yet no guidelines concerning the CI dosing of amoxicillin. The present study was developed to describe the CI pharmacokinetics and -dynamics of amoxicillin during the first 3 days of life in search of the optimal dosing regimen. Neonates with a gestational age above 34 weeks, at risk of neonatal infection and requiring amoxicillin therapy, were included. Serum concentrations of amoxicillin were measured during CI on days 1 and 3 in the steady state. Twenty-two serum samples of 11 patients were collected. All patients reached and retained serum concentrations of amoxicillin within the therapeutic range without exceeding the toxic concentration (serum concentrations on day 1 mean 55.4 mg/l, range 30.9–69.5, SD 10.5, and on day 3 48.8 mg/l, range 25.5–92.4, SD 18.4). There was no significant decrease in concentration from day 1 to day 3 (p = 0.38). This study showed therapeutic, nontoxic concentrations of amoxicillin in neonates on CI of amoxicillin in the first 3 days of life. Randomized controlled trials should reveal whether the clinical benefits of the CI of amoxicillin exceed those of ID regimens.     

<Emphasis Type="Italic">Echinacea purpurea</Emphasis> and osteopathic manipulative treatment in children with recurrent otitis media: a randomized controlled trial

Background  

Recurrent otitis media is a common problem in young children. Echinacea and osteopathic manipulative treatment have been proposed as preventive measures, but have been inadequately studied. This study was designed to assess the efficacy of Echinacea purpurea and/or osteopathic manipulative treatment (OMT) for prevention of acute otitis media in otitis-prone children.     

Mometasone furoate nasal spray increases the number of minimal-symptom days in patients with acute rhinosinusitis

BackgroundAcute rhinosinusitis (ARS) is triggered by viral or, uncommonly, bacterial infection, causing inflammatory symptoms for ≤12 weeks.ObjectiveTo investigate effects of mometasone furoate nasal spray (MFNS) vs amoxicillin and placebo on minimal-symptom days.MethodsA double-blind, parallel-group, placebo- and active-controlled 15-day study randomly assigned patients 12 years of age or older to MFNS 200 μg twice daily, MFNS 200 μg once daily, amoxicillin 500 mg 3 times daily, or placebo.Patients had baseline rhinosinusitis major symptom score (MSS; combined rhinorrhea, postnasal drip, congestion, sinus headache, facial pain) of ≥5 and ≤12 (maximum: 15) for 7 to 28 days; scores were similar among groups. Minimal-symptom days and minimal-congestion days were defined post hoc by average am/pm MSS ≤4 and average am/pm congestion ≤1.ResultsMFNS twice daily (n = 234) showed more minimal-symptom days vs placebo (n = 246) (62.69% vs 50.33%; P < .0001) or amoxicillin (n = 248) (54.35%; P = .0040). The MFNS QD was associated with numerically more minimal-symptom days than amoxicillin or placebo (54.72%; P ≤ .8982). MFNS was associated with more minimal-congestion days than placebo (72.97%, 67.73%, and 56.67% for twice daily, once daily, and placebo; P < .0001, each vs placebo) and MFNS BID with more minimal-congestion days than amoxicillin (72.97% vs 64.15%; P = .0007). Median time to first minimal-symptom day sustained until study end was 8.5 days for MFNS BID vs. 11 for placebo (P = .0085).ConclusionMFNS 200 μg twice daily significantly increased minimal-symptom days vs amoxicillin or placebo in patients with ARS. Results of this intranasal corticosteroids (INS) therapy indicate it can improve outcomes and potentially reduce inappropriate antibiotic use.     

Treatment of acute otitis media: comparative study of efficacy of cefatrizine and amoxicillin-clavulanic acid

Fourty hospitalized patients (15 children, 25 adults) suffering from acute otitis media have been treated with either cefatrizine or amoxycillin-clavulanic acid. Bacteriological samples were done during surgery by tympanocentesis (N = 33) or by sampling of middle ear fluid specimens (13). H. influenzae was the most common isolate, following by Enterobacteriaceae, S. aureus, P. aeruginosa, and S. pneumoniae. We conclude that these two antibiotics can be used for treatment of acute otitis media in our country even in adults where the order of frequency of bacteria is different from those reported in children.     

The Fimbria Gene Cluster of Nonencapsulated Haemophilus influenzae

The occurrence of fimbria gene clusters in nonencapsulated Haemophilus influenzae strains from chronic bronchitis patients (n = 58), patients with acute otitis media (n = 13), and healthy carriers (n = 12) was determined by DNA hybridization and PCR, based on sequences of fimbriate H. influenzae type b. Although an average of 18% of all nonencapsulated strains had a fimbria gene cluster consisting of hifA to hifE inserted in the chromosome between purE and pepN, differences in the frequency of fimbria cluster-positive strains were observed, depending on the source of isolates. The compositions of the fimbria gene clusters of seven strains from chronic bronchitis patients and one strain from an otitis media patient were analyzed in more detail. After enrichment for fimbria expression, the promoter of the gene cluster contained 10 TA repeats (n = 2), leading to optimal positioning between the −10 and −35 promoter regions. The promoter regions of five fimbria-negative strains were sequenced; four were found to have nine TA repeats, and one had only four TA repeats. The protein sequence of three ganglioside GM1-specific HifA adhesins consisted of conserved regions intermingled with regions of sequence diversity. hifA appeared to be flanked by intergenic regions that varied between strains and contained both direct and inverted DNA repeats. Since noncoding DNA between hifA and purE has not been found in H. influenzae type b, these DNA sequences are probably not essential for fimbria expression. An analysis of strains lacking the gene cluster revealed the presence of similar sequences in 13 of 15 strains from chronic bronchitis patients, 5 of 5 strains from otitis media patients, and 3 of 5 strains from healthy carriers. The lengths of these intergenic regions were the same for multiple isolates of strains obtained during persistent infections. The presence or absence and the composition of the fimbria gene cluster and other sequences between the flanking genes purE and pepN suggest that the fimbria gene cluster was originally contained on a mobile element.