Potentially Pathogenic Organisms in Stools and Their Association With Acute Diarrheal Illness in Children Aged <2 Years

BACKGROUND

Acute diarrheal illness (ADI) causes a substantial disease burden in high-income countries. We investigated associations between potentially pathogenic organisms in stools and ADI by polymerase chain reaction (PCR) in Australian children aged <2 years.

METHODS

Children in a community-based birth cohort had gastrointestinal symptoms recorded daily and stool samples collected weekly until their second birthday. Diarrhea was defined as ≥3 liquid or looser than normal stools within a 24-hour period. PCR assays tested for 11 viruses, 5 bacteria, and 4 protozoa. Detections of a new organism or of the same following at least 2 negative tests were linked to ADIs, and incidence rates and estimates of association with ADI were calculated.

RESULTS

One hundred fifty-four children provided 11 111 stool samples during 240 child-years of observation, and 228 ADIs were linked to samples. Overall, 6105 (55%) samples tested positive for a target organism. The incidence rate of 2967 new detections was 11.9 (95% confidence interval 11.4-12.3) per child-year, with 2561 (92%) new detections unrelated to an ADI. The relative risk of an ADI was 1.5-6.4 times greater for new detections of adenovirus, enterovirus, norovirus GII, parechovirus A, wild-type rotavirus, sapovirus GI/II/IV/V, Salmonella, Blastocystis, and Cryptosporidium, compared to when these were absent.

CONCLUSIONS

Wild-type rotavirus, norovirus GII, sapovirus GI/II/IV/V, adenovirus 40/41, and Salmonella were associated with ADI in this age group and setting. However, high levels of asymptomatic shedding of potential pathogens in stools from children may contribute to diagnostic confusion when children present with an episode of ADI.

Predominant Bacterial and Viral Otopathogens Identified Within the Respiratory Tract and Middle Ear of Urban Australian Children Experiencing Otitis Media Are Diversely Distributed

Background

Otitis media (OM) is one of the most common infections in young children, arising from bacterial and/or viral infection of the middle ear. Globally, Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) are the predominant bacterial otopathogens. Importantly, common upper respiratory viruses are increasingly recognized contributors to the polymicrobial pathogenesis of OM. This study aimed to identify predominant bacteria and viruses in the nasopharynx, adenoids and middle ears of peri-urban/urban South-East Queensland Australian children, with and without clinical history of chronic otitis media with effusion (COME) and/or recurrent acute otitis media (RAOM).

Methods

Sixty children, 43 diagnosed with OM and 17 controls with no clinical history of OM from peri-urban/urban South-East Queensland community were recruited to the study. Respiratory tract bacterial and viral presence were examined within nasopharyngeal swabs (NPS), middle ear effusions (MEE) and adenoids, using real-time polymerase chain reaction (RT-PCR) and bacterial culture.

Results

At least one otopathogen present was observed in all adenoid samples, 86.1% and 82.4% of NPS for children with and without OM, respectively, and 47.1% of the MEE from the children with OM. NTHi was the most commonly detected bacteria in both the OM and control cohorts within the adenoids (90.0% vs 93.8%), nasopharynx (67.4% vs 58.8%) respectively, and in the MEE (OM cohort 25.9%). Viruses were detected in all adenoid samples, 67.4% vs 47.1% of the NPS from the OM and control cohorts, respectively, and 37% of the MEE. Rhinovirus was the predominant virus identified in the adenoids (85.0% vs 68.8%) and nasopharynx (37.2% vs 41.2%) from the OM and control cohorts, respectively, and the MEE (19.8%).

Conclusions

NTHi and rhinovirus are predominant otopathogens within the upper respiratory tract of children with and without OM from peri-urban and urban South-East Queensland, Australia. The presence of bacterial otopathogens within the middle ear is more predictive of concurrent URT infection than was observed for viruses, and the high otopathogen carriage within adenoid tissues confirms the complex polymicrobial environment in children, regardless of OM history.

High coverage of diverse invasive meningococcal serogroup B strains by the 4-component vaccine 4CMenB in Australia, 2007-2011: Concordant predictions between MATS and genetic MATS

Meningococcal serogroup B (MenB) accounts for an important proportion of invasive meningococcal disease (IMD). The 4-component vaccine against MenB (4CMenB) is composed of factor H binding protein (fHbp), neisserial heparin-binding antigen (NHBA), Neisseria adhesin A (NadA), and outer membrane vesicles of the New Zealand strain with Porin 1.4. A meningococcal antigen typing system (MATS) and a fully genomic approach, genetic MATS (gMATS), were developed to predict coverage of MenB strains by 4CMenB. We characterized 520 MenB invasive disease isolates collected over a 5-year period (January 2007-December 2011) from all Australian states/territories by multilocus sequence typing and estimated strain coverage by 4CMenB. The clonal complexes most frequently identified were ST-41/44 CC/Lineage 3 (39.4%) and ST-32 CC/ET-5 CC (23.7%). The overall MATS predicted coverage was 74.6% (95% coverage interval: 61.1%-85.6%). The overall gMATS prediction was 81.0% (lower-upper limit: 75.0-86.9%), showing 91.5% accuracy compared with MATS. Overall, 23.7% and 13.1% (MATS) and 26.0% and 14.0% (gMATS) of isolates were covered by at least 2 and 3 vaccine antigens, respectively, with fHbp and NHBA contributing the most to coverage. When stratified by year of isolate collection, state/territory and age group, MATS and gMATS strain coverage predictions were consistent across all strata. The high coverage predicted by MATS and gMATS indicates that 4CMenB vaccination may have an impact on the burden of MenB-caused IMD in Australia. gMATS can be used in the future to monitor variations in 4CMenB strain coverage over time and geographical areas even for non-culture confirmed IMD cases.

Bacterial colonization dynamics associated with respiratory syncytial virus during early childhood

Respiratory syncytial virus (RSV) is an important cause of early life acute respiratory infections. Potentially pathogenic respiratory bacteria, including Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae are frequently detected during RSV infections and associated with increased illness severity. However, the temporal dynamics of bacterial colonization associated with RSV infection remain unclear. We used weekly nasal swab data from a prospective longitudinal birth cohort in Brisbane, Australia, to investigate bacterial colonization patterns within children aged less than 2 years in the 4-week period before and after an RSV infection. During 54 RSV infection episodes recorded in 47 children, both S. pneumoniae and M. catarrhalis were detected frequently (in 33 [61.1%] and 26 [48.1%] RSV infections, respectively). In most cases, S. pneumoniae and M. catarrhalis colonization preceded the viral infection, with the nasal load of each increasing during RSV infection. Generally, the dominant serotype of S. pneumoniae remained consistent in the 1 to 2 weeks immediately before and after RSV infection. Little evidence was found to indicate that prior colonization with either bacteria predisposed participants to developing RSV infection during the annual seasonal epidemic. Possible coacquisition events, where the bacteria species was first detected with RSV and not in the preceding 4 weeks, were observed in approximately 20% of RSV/S. pneumoniae and RSV/M. catarrhalis codetections. Taken together our results indicate that RSV generally triggered an outgrowth, rather than a new acquisition, of S. pneumoniae and M. catarrhalis from the resident microbial community.

Timing of First Respiratory Virus Detections in Infants: A Community-Based Birth Cohort Study

Background

Determining timing of first virus detection episodes (fVDEs) for different respiratory viruses in infants identifies risk periods and informs preventive interventions, including vaccination. We describe the ages and nature of fVDEs in an infant birth cohort and explore factors associated with increased odds of symptomatic fVDEs.

Methods

The Observational Research in Childhood Infectious Diseases (ORChID) study is a community-based birth cohort describing acute respiratory infections in infants until their second birthday. Parents recorded daily symptoms and collected nose swabs weekly, which were batch-tested using polymerase chain reaction assays for 17 respiratory viruses.

Results

One hundred fifty-eight infants participated in ORChID. The median age for fVDEs was 2.9 months for human rhinovirus (HRV) but was ≥13.9 months for other respiratory viruses. Overall, 52% of HRV fVDEs were symptomatic, compared with 57%–83% of other fVDEs. Respiratory syncytial virus and human metapneumovirus fVDEs were more severe than HRV fVDEs. Older age and the winter season were associated with symptomatic episodes.

Conclusions

Infants do not always experience respiratory symptoms with their fVDE. Predominance of early HRV detections highlights the need for timing any intervention early in life. fVDEs from other respiratory viruses most commonly occur when maternal vaccines may no longer provide protection.

Bacteria and viruses in the nasopharynx immediately prior to onset of acute lower respiratory infections in Indigenous Australian children

Acute lower respiratory infection (ALRI) is a major cause of hospitalization for Indigenous children in remote regions of Australia. The associated microbiology remains unclear. Our aim was to determine whether the microbes present in the nasopharynx before an ALRI were associated with its onset. A retrospective case-control/crossover study among Indigenous children aged up to 2 years. ALRI cases identified by medical note review were eligible where nasopharyngeal swabs were available: (1) 0–21 days before ALRI onset (case); (2) 90–180 days before ALRI onset (same child controls); and (3) from time and age-matched children without ALRI (different child controls). PCR assays determined the presence and/or load of selected respiratory pathogens. Among 104 children (182 recorded ALRI episodes), 120 case-same child control and 170 case-different child control swab pairs were identified. Human adenoviruses (HAdV) were more prevalent in cases compared to same child controls (18 vs 7%; OR = 3.08, 95% CI 1.22–7.76, p = 0.017), but this association was not significant in cases versus different child controls (15 vs 10%; OR = 1.93, 95% CI 0.97–3.87 (p = 0.063). No other microbes were more prevalent in cases compared to controls. Streptococcus pneumoniae (74%), Haemophilus influenzae (75%) and Moraxella catarrhalis (88%) were commonly identified across all swabs. In a pediatric population with a high detection rate of nasopharyngeal microbes, HAdV was the only pathogen detected in the period before illness presentation that was significantly associated with ALRI onset. Detection of other potential ALRI pathogens was similar between cases and controls.

Presence of atopy increases the risk of asthma relapse

OBJECTIVES

To describe the point prevalence of respiratory viruses/atypical bacteria using PCR and evaluate the impact of respiratory viruses/atypical bacteria and atopy on acute severity and clinical recovery in children with hospitalised and non-hospitalised asthma exacerbations.

DESIGN

This was a prospective study performed during 2009-2011.

SETTING

The study was performed in the emergency departments of two hospitals.

PATIENTS

244 children aged 2-16 years presenting with acute asthma to the emergency departments were recruited. A nasopharyngeal aspirate and allergen skin prick test were performed.

MAIN OUTCOME MEASURES

The outcomes were divided into (1) acute severity outcomes (Australian National Asthma Council assessment, hospitalisation, Functional Severity Scale, Acute Asthma Score, asthma quality of life questionnaires for parents (PACQLQ) on presentation, asthma diary scores (ADS) on presentation and length of hospitalisation) and (2) recovery outcomes (PACQLQ for 21 days, ADS for 14 days and representation for asthma for 21 days).

RESULTS

PCR for viruses/atypical bacteria was positive in 81.7% of children (75.1% human rhinovirus, codetection in 14.2%). Mycoplasma pneumoniae and Chlamydophila pneumoniae were rarely detected. The presence of micro-organisms had little impact on acute asthma or recovery outcomes. Children with atopy were significantly more likely to relapse and represent for medical care by day 14 (OR 1.11, 95% CI 1.00 to 1.23).

CONCLUSIONS

The presence of any viruses is associated with asthma exacerbations but does not appear to influence asthma recovery. In contrast, atopy is associated with asthma relapse. M. pneumoniae and C. pneumoniae are rare triggers of acute asthma in young children.

Viruses causing lower respiratory symptoms in young children: findings from the ORChID birth cohort

INTRODUCTION

Viral acute respiratory infections (ARIs) cause substantial child morbidity. Sensitive molecular-based assays aid virus detection, but the clinical significance of positive tests remains uncertain as some viruses may be found in both acutely ill and healthy children. We describe disease-pathogen associations of respiratory viruses and quantify virus-specific attributable risk of ARIs in healthy children during the first 2 years of life.

METHODS

One hundred fifty-eight term newborn babies in Brisbane, Australia, were recruited progressively into a longitudinal, community-based, birth cohort study conducted between September 2010 and October 2014. A daily tick-box diary captured predefined respiratory symptoms from birth until their second birthday. Weekly parent-collected nasal swabs were batch-tested for 17 respiratory viruses by PCR assays, allowing calculation of virus-specific attributable fractions in the exposed (AFE) to determine the proportion of virus-positive children whose ARI symptoms could be attributed to that particular virus.

RESULTS

Of 8100 nasal swabs analysed, 2646 (32.7%) were virus-positive (275 virus codetections, 3.4%), with human rhinoviruses accounting for 2058/2646 (77.8%) positive swabs. Viruses were detected in 1154/1530 (75.4%) ARI episodes and in 984/4308 (22.8%) swabs from asymptomatic periods. Respiratory syncytial virus (AFE: 68% (95% CI 45% to 82%)) and human metapneumovirus (AFE: 69% (95% CI 43% to 83%)) were strongly associated with higher risk of lower respiratory symptoms.

DISCUSSION

The strong association of respiratory syncytial virus and human metapneumovirus with ARIs and lower respiratory symptoms in young children managed within the community indicates successful development of vaccines against these two viruses should provide substantial health benefits.

Detection of Toscana virus from an adult traveler returning to Australia with encephalitis

Toscana virus (TOSV) is identified in sandflies, animals, and humans around the Mediterranean Sea. TOSV has not been reported in Australia. During investigations of cerebrospinal fluid samples from patients with encephalitis, TOSV genetic sequences were identified in a traveler returning to Australia from Europe. TOSV should be considered, especially during May to October, in travelers to Australia who embarked in countries in and around the Mediterranean Sea and who subsequently present for medical care because of neurological symptoms.

Upper airway viruses and bacteria in urban Aboriginal and Torres Strait Islander children in Brisbane, Australia: a cross-sectional study

BACKGROUND

Respiratory morbidity in Australian Indigenous children is higher than their non-Indigenous counterparts, irrespective of urban or remote residence. There are limited studies addressing acute respiratory illness (ARI) in urban Indigenous children, particularly those that address the upper airway microbiome and its relationship to disease. We aimed to describe the prevalence of upper airway viruses and bacteria in symptomatic and asymptomatic urban-based Australian Indigenous children aged less than 5 years.

METHODS

A cross-sectional analysis of data collected at baseline in an ongoing prospective cohort study of urban Aboriginal and Torres Strait Islander children registered with a primary health care service in the northern suburbs of Brisbane, Australia. Clinical, demographic and epidemiological data and bilateral anterior nasal swabs were collected on enrolment. Polymerase chain reaction was performed on nasal swabs to detect 17 respiratory viruses and 7 bacteria. The primary outcome was the prevalence of these microbes at enrolment. Logistic regression was performed to investigate differences in microbe prevalence between children with and without acute respiratory illness with cough as a symptom (ARIwC) at time of specimen collection.

RESULTS

Between February 2013 and October 2015, 164 children were enrolled. The median age at enrolment was 18.0 months (IQR 7.2-34.3), 49.4% were boys and 56 children (34.2%) had ARIwC. Overall, 133/164 (81%) nasal swabs were positive for at least one organism; 131 (79.9%) for any bacteria, 59 (36.2%) for any virus and 57 (34.8%) for both viruses and bacteria. Co-detection of viruses and bacteria was more common in females than males (61.4% vs 38.6%, p = 0.044). No microbes, alone or in combination, were significantly associated with the presence of ARIwC.

CONCLUSIONS

The prevalence of upper airways microbes in asymptomatic children is similar to non-Indigenous children with ARIwC from the same region. Determining the aetiology of ARIwC in this community is complicated by the high prevalence of multiple respiratory pathogens in the upper airways.

STUDY REGISTRATION

Australia New Zealand Clinical Trial Registry Registration Number: 12,614,001,214,628. Retrospectively registered.

Effectiveness of a cough management algorithm at the transitional phase from acute to chronic cough in Australian children aged <15 years: protocol for a randomised controlled trial

INTRODUCTION

Acute respiratory infections (ARIs) are leading causes of hospitalisation in Australian children and, if recurrent, are associated with increased risk of chronic pulmonary disorders later in life. Chronic (>4 weeks) cough in children following ARI is associated with decreased quality-of-life scores and increased health and societal economic costs. We will determine whether a validated evidence-based cough algorithm, initiated when chronic cough is first diagnosed after presentation with ARI, improves clinical outcomes in children compared with usual care.

METHODS AND ANALYSIS

A multicentre, parallel group, open-label, randomised controlled trial, nested within a prospective cohort study in Southeast Queensland, Australia, is underway. 750 children aged <15 years will be enrolled and followed weekly for 8 weeks after presenting with an ARI with cough. 214 children from this cohort with persistent cough at day 28 will be randomised to either early initiation of a cough management algorithm or usual care (107 per group). Randomisation is stratified by reason for presentation, site and total cough duration at day 28 (<6 and ≥6 weeks). Demographic details, risk factors, clinical histories, examination findings, cost-of-illness data, an anterior nasal swab and parent and child exhaled carbon monoxide levels (when age appropriate) are collected at enrolment. Weekly contacts will collect cough status and cost-of-illness data. Additional nasal swabs are collected at days 28 and 56. The primary outcome is time-to-cough resolution. Secondary outcomes include direct and indirect costs of illness and the predictors of chronic cough postpresentation.

ETHICS AND DISSEMINATION

The Children's Health Queensland (HREC/15/QRCH/15) and the Queensland University of Technology University (1500000132) Research Ethics Committees have approved the study. The study will inform best-practice management of cough in children.

TRIAL REGISTRATION NUMBER

ACTRN12615000132549.

Upper airway viruses and bacteria and clinical outcomes in children with cough

BACKGROUND

Cough is symptomatic of a broad range of acute and chronic pediatric respiratory illnesses. No studies in children have tested for an extended panel of upper airway respiratory viruses and bacteria to identify whether they predict cough outcomes, irrespective of clinical diagnosis at the time of acute respiratory illness (ARI). We therefore determined whether upper airway microbes independently predicted hospitalization and persistent cough 28-days later in children presenting with an ARI, including cough as a symptom.

METHODS

A cohort study of children aged <15-years were followed for 28-days after presenting to a pediatric emergency department with an ARI where cough was also a symptom. Socio-demographic factors, presenting clinical features and a bilateral anterior nasal swab were collected at enrolment. Polymerase chain reaction assays tested for seven respiratory bacteria and 17 viruses. Predictors of hospitalization and persistent cough at day-28 were evaluated in logistic regression models.

RESULTS

Eight hundred and seventeen children were included in the analysis; median age 27.7-months. 116 (14.2%, 95%CI 11.8, 16.6) children were hospitalized and 163 (20.0%, 95%CI 17.2, 22.7) had persistent cough at day-28. Hospitalized children were more likely to have RSV A or B detected on nasal swab than those not admitted (adjusted relative risk (aRR) 1.8, 95%CI 1.0, 3.3). M. catarrhalis was the only microbial difference between children with and without cough persistence (aRR for those with cough at day 28: 2.1, 95%CI 1.3, 3.1).

DISCUSSION

An etiologic role for M. catarrhalis in the pathogenesis of persistent cough post-ARI is worth exploring, especially given the burden of chronic cough in children and its relationship with chronic lung disease. Pediatr Pulmonol. 2017;52:373-381. © 2016 Wiley Periodicals, Inc.

The burden of community-managed acute respiratory infections in the first 2-years of life

BACKGROUND

Contemporary information on acute respiratory infections (ARIs) in children is based on hospital cohorts, primary healthcare presentations, and high-risk birth cohort studies. We describe the burden and determinants of symptomatic episodes of ARIs in unselected healthy infants in the first 2-years of life.

METHODS

One hundred and fifty-four infants from subtropical Brisbane, Australia participated in a longitudinal, community-based birth cohort study. A daily tick-box diary captured pre-defined respiratory symptoms. Parents also completed a burden diary, recording family physician and hospital visits, and antibiotic use.

RESULTS

Participants contributed 88,032 child-days (78.2% of expected), of which 17,316 (19.7%) days were symptomatic during 1,651 ARI episodes: incidence rate 0.56 ARIs per child-month (95%CI: 0.54, 0.59). Runny nose (14,220 days; 6.0-days median duration) and dry cough (6,880 days; 4.0-days median duration) were reported most frequently. Overall, 955 burden diaries recorded 455 family physician visits (1-8 visits per ARI) and 48 hospital presentations, including six hospital admissions. Antibiotics were prescribed on 209 occasions (21.9% of ARI episodes where burden diary submitted). Increasing age, non-summer seasons, and attendance at childcare were associated with an increased risk of ARI.

CONCLUSIONS

ARIs are a common cause of morbidity in the first 2-years of life, with children experiencing 13 discrete ARI episodes and almost 5-months of respiratory symptoms. Most ARIs are managed in the community by parents and family physicians. Antibiotic prescribing remains common for ARIs in young children. Secular societal changes, including greater use of childcare in early childhood, may have maintained the high ARI incidence in this age-group. Pediatr Pulmonol. 2016;51:1336-1346. © 2016 Wiley Periodicals, Inc.

Detection of viruses in weekly stool specimens collected during the first 2 years of life: A pilot study of five healthy Australian infants in the rotavirus vaccine era

Several viruses are associated with gastroenteritis in infants. This pilot study, nested within a larger community-based project of early childhood infections, collected daily symptom data and 511 weekly stool samples from five healthy, fully vaccinated, term infants from birth until their second birthday. Real-time PCR assays were used to detect six enteric viruses. Frequent, silent shedding of one or more of the six viruses was observed, particularly involving adenovirus where shedding could be for up to 3 months without gastrointestinal symptoms. These pilot data demonstrate that a positive PCR result for enteric viruses may not always indicate the cause of childhood gastroenteritis. J. Med. Virol. 89:917-921, 2017. © 2016 Wiley Periodicals, Inc.

Prevalence, codetection and seasonal distribution of upper airway viruses and bacteria in children with acute respiratory illnesses with cough as a symptom

Most studies exploring the role of upper airway viruses and bacteria in paediatric acute respiratory infections (ARI) focus on specific clinical diagnoses and/or do not account for virus-bacteria interactions. We aimed to describe the frequency and predictors of virus and bacteria codetection in children with ARI and cough, irrespective of clinical diagnosis. Bilateral nasal swabs, demographic, clinical and risk factor data were collected at enrollment in children aged <15 years presenting to an emergency department with an ARI and where cough was a symptom. Swabs were tested by polymerase chain reaction for 17 respiratory viruses and seven respiratory bacteria. Logistic regression was used to investigate associations between child characteristics and codetection of the organisms of interest. Between December 2011 and August 2014, swabs were collected from 817 (93.3%) of 876 enrolled children, median age 27.7 months (interquartile range 13.9-60.3 months). Overall, 740 (90.6%) of 817 specimens were positive for any organism. Both viruses and bacteria were detected in 423 specimens (51.8%). Factors associated with codetection were age (adjusted odds ratio (aOR) for age <12 months = 4.9, 95% confidence interval (CI) 3.0, 7.9; age 12 to <24 months = 6.0, 95% CI 3.7, 9.8; age 24 to <60 months = 2.4, 95% CI 1.5, 3.9), male gender (aOR 1.46; 95% CI 1.1, 2.0), child care attendance (aOR 2.0; 95% CI 1.4, 2.8) and winter enrollment (aOR 2.0; 95% CI 1.3, 3.0). Haemophilus influenzae dominated the virus-bacteria pairs. Virus-H. influenzae interactions in ARI should be investigated further, especially as the contribution of nontypeable H. influenzae to acute and chronic respiratory diseases is being increasingly recognized.

Direct urine polymerase chain reaction for chlamydia and gonorrhoea: a simple means of bringing high-throughput rapid testing to remote settings?

Background Rapid point-of-care tests (POCTs) for chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) have the potential to confer health benefits in certain populations even at moderate sensitivities; however, suitable POCTs for these organisms are currently lacking.

METHODS

In this study, we investigated the use of direct urine polymerase chain reaction (PCR), with the view of implementing a simplified PCR strategy for high-throughput chlamydia and gonorrhoea screening in remote settings. Briefly, a simple dilution of the urine was performed before adding it directly to a real-time PCR reaction. The method was evaluated using 134 stored urine specimens that had been submitted for chlamydia and gonorrhoea testing and had been tested using a commercial C. trachomatis and N. gonorrhoeae PCR method. These included samples that were PCR-positive for chlamydia (n=87), gonorrhoea (n=16) or both (n=2). Direct urine testing was conducted using previously described in-house real-time PCR methods for C. trachomatis and N. gonorrhoeae as well as for recognised N.gonorrhoeae antimicrobial resistance mechanisms.

RESULTS

The overall sensitivities and specificities of the direct urine PCR were 78% and 100% for chlamydia, and 83% and 100% for gonorrhoea. N.gonorrhoeae penicillin and quinolone resistance mechanisms were characterised in 14 of the 18 N. gonorrhoeae-positive samples.

CONCLUSIONS

The results of this study show that the simplified PCR strategy may be a feasible approach for rapid screening and improving chlamydia and gonorrhoea treatment in remote settings.

Upper airway viruses and bacteria detection in clinical pneumonia in a population with high nasal colonisation do not relate to clinical signs

Indigenous Australian children have high (up to 90%) rates of nasopharyngeal microbial colonisation and of hospitalisation for pneumonia. In Indigenous children hospitalised with pneumonia in Central Australia, we describe the nasopharyngeal detection of viruses and bacteria and assessed whether their presence related to signs of pneumonia (tachypnoea and/or chest in-drawing) on hospital admission and during subsequent days. Nasopharyngeal swabs (NPS) and data were prospectively collected from 145 children (median age = 23.5 months, interquartile range [IQR] 8.7–50) hospitalised with pneumonia at Alice Springs Hospital, Australia, between April 2001 and July 2002. The cohort was enrolled in a randomised controlled study using zinc and/or vitamin A supplementation. NPS were taken within 24 hours of hospitalisation and kept frozen at-80°C until analysed in 2014. Polymerase chain reaction (PCR) was used to detect Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, Chlamydophila pneumoniae, Mycoplasma pneumoniae, and 16 respiratory viruses. Uni- and multi-variate analyses were used to examine the relationships. One or more organisms were present in 137 (94.5%) NPS; 133 (91.7%) detected ≥ 1 bacterium, 34 (37.2%) for ≥ 1 virus and 50 (34.5%) were positive for both viruses and bacteria. C. pneumoniae (n = 3) and M. pneumoniae (n = 2) were rare. In multi-variate analyses, age < 12 months (odds ratio [OR] 6.6 [95% confidence interval {CI} 1.7–25.4]) and fever (OR 4.1 [95% CI 1.7–10.4]) were associated with tachypnoea and chest in-drawing. However the presence of bacteria and/or virus type was not associated with tachypnoea and/or chest in-drawing on admission or during recovery. In children with high nasopharyngeal microbial colonisation rates, the utility of NPS in determining the diagnosis of clinical pneumonia or duration of tachypnoea or in-drawing is likely limited. Larger cohort and case-control studies are required to confirm our findings.

Acquisition of human polyomaviruses in the first 18 months of life

We investigated the presence of 4 human polyomaviruses (PyVs) (WU, KI, Merkel cell, and Malawi) in respiratory specimens from a community-based birth cohort. These viruses typically were acquired when children were ≈1 year of age. We provide evidence that WU, KI, and Malawi, but not Merkel cell PyVs, might have a role in respiratory infections.

The respiratory health of urban indigenous children aged less than 5 years: study protocol for a prospective cohort study

BACKGROUND

Despite the burden of acute respiratory illnesses (ARI) among Aboriginal and Torres Strait Islander children being a substantial cause of childhood morbidity and associated costs to families, communities and the health system, data on disease burden in urban children are lacking. Consequently evidence-based decision-making, data management guidelines, health resourcing for primary health care services and prevention strategies are lacking. This study aims to comprehensively describe the epidemiology, impact and outcomes of ARI in urban Aboriginal and Torres Strait Islander children (hereafter referred to as Indigenous) in the greater Brisbane area.

METHODS/DESIGN

An ongoing prospective cohort study of Indigenous children aged less than five years registered with a primary health care service in Northern Brisbane, Queensland, Australia. Children are recruited at time of presentation to the service for any reason. Demographic, epidemiological, risk factor, microbiological, economic and clinical data are collected at enrolment. Enrolled children are followed for 12 months during which time ARI events, changes in child characteristics over time and monthly nasal swabs are collected. Children who develop an ARI with cough as a symptom during the study period are more intensely followed-up for 28 (±3) days including weekly nasal swabs and parent completed cough diary cards. Children with persistent cough at day 28 post-ARI are reviewed by a paediatrician.

DISCUSSION

Our study will be one of the first to comprehensively evaluate the natural history, epidemiology, aetiology, economic impact and outcomes of ARIs in this population. The results will inform studies for the development of evidence-based guidelines to improve the early detection, prevention and management of chronic cough and setting of priorities in children during and after ARI.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry Registration Number: 12614001214628 . Registered 18 November 2014.

Specific rolling circle amplification of low-copy human polyomaviruses BKV, HPyV6, HPyV7, TSPyV, and STLPyV

Eleven new human polyomaviruses have been recently discovered, yet for most of these viruses, little is known of their biology and clinical impact. Rolling circle amplification (RCA) is an ideal method for the amplification of the circular polyomavirus genome due to its high fidelity amplification of circular DNA. In this study, a modified RCA method was developed to selectively amplify a range of polyomavirus genomes. Initial evaluation showed a multiplexed temperature-graded reaction profile gave the best yield and sensitivity in amplifying BK polyomavirus in a background of human DNA, with up to 1 × 10(8)-fold increases in viral genomes from as little as 10 genome copies per reaction. Furthermore, the method proved to be more sensitive and provided a 200-fold greater yield than that of random hexamers based standard RCA. Application of the method to other novel human polyomaviruses showed successful amplification of TSPyV, HPyV6, HPyV7, and STLPyV from low-viral load positive clinical samples, with viral genome enrichment ranging from 1 × 10(8) up to 1 × 10(10). This directed RCA method can be applied to selectively amplify other low-copy polyomaviral genomes from a background of competing non-specific DNA, and is a useful tool in further research into the rapidly expanding Polyomaviridae family.

Three-weekly doses of azithromycin for indigenous infants hospitalized with bronchiolitis: a multicentre, randomized, placebo-controlled trial

BACKGROUND

Bronchiolitis is a major health burden in infants globally, particularly among Indigenous populations. It is unknown if 3 weeks of azithromycin improve clinical outcomes beyond the hospitalization period. In an international, double-blind randomized controlled trial, we determined if 3 weeks of azithromycin improved clinical outcomes in Indigenous infants hospitalized with bronchiolitis.

METHODS

Infants aged ≤24 months were enrolled from three centers and randomized to receive three once-weekly doses of either azithromycin (30 mg/kg) or placebo. Nasopharyngeal swabs were collected at baseline and 48 h later. Primary endpoints were hospital length of stay (LOS) and duration of oxygen supplementation monitored every 12 h until judged ready for discharge. Secondary outcomes were: day-21 symptom/signs, respiratory rehospitalizations within 6 months post-discharge and impact upon nasopharyngeal bacteria and virus shedding at 48 h.

RESULTS

Two hundred nineteen infants were randomized (n = 106 azithromycin, n = 113 placebo). No significant between-group differences were found for LOS (median 54 h for each group, difference = 0 h, 95% CI: -6, 8; p = 0.8), time receiving oxygen (azithromycin = 40 h, placebo = 35 h, group difference = 5 h, 95% CI: -8, 11; p = 0.7), day-21 symptom/signs, or rehospitalization within 6 months (azithromycin n = 31, placebo n = 25 infants, p = 0.2). Azithromycin reduced nasopharyngeal bacterial carriage (between-group difference 0.4 bacteria/child, 95% CI: 0.2, 0.6; p < 0.001), but had no significant effect upon virus detection rates.

CONCLUSION

Despite reducing nasopharyngeal bacterial carriage, three large once-weekly doses of azithromycin did not confer any benefit over placebo during the bronchiolitis illness or 6 months post hospitalization. Azithromycin should not be used routinely to treat infants hospitalized with bronchiolitis.

CLINICAL TRIAL REGISTRATION

The trial was registered with the Australian and New Zealand Clinical Trials Register: Clinical trials number: ACTRN1261000036099.

Respiratory viruses in exacerbations of non-cystic fibrosis bronchiectasis in children

BACKGROUND

Respiratory viral infections precipitate exacerbations of chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease though similar data in non-cystic fibrosis (CF) bronchiectasis are missing. Our study aimed to determine the point prevalence of viruses associated with exacerbations and evaluate clinical and investigational differences between virus-positive and -negative exacerbations in children with bronchiectasis.

METHODS

A cohort of 69 children (median age 7 years) with non-CF bronchiectasis was prospectively followed for 900 child-months. PCR for 16 respiratory viruses was performed on nasopharyngeal aspirates collected during 77 paediatric pulmonologist-defined exacerbations. Clinical data, systemic (C reactive protein (CRP), IL-6, procalcitonin, amyloid-A, fibrinogen) and lung function parameters were also collected.

FINDINGS

Respiratory viruses were detected during 37 (48%) exacerbations: human rhinovirus (HRV) in 20; an enterovirus or bocavirus in four each; adenoviruses, metapneumovirus, influenza A virus, respiratory syncytial virus, parainfluenza virus 3 or 4 in two each; coronavirus or parainfluenza virus 1 and 2 in one each. Viral codetections occurred in 6 (8%) exacerbations. HRV-As (n=9) were more likely to be present than HRV-Cs (n=2). Children with virus-positive exacerbations were more likely to require hospitalisation (59% vs 32.5% (p=0.02)) and have fever (OR 3.1, 95% CI 1.2 to 11.1), hypoxia (OR 25.5, 95% CI 2.0 to 322.6), chest signs (OR 3.3, 95% CI 1.1 to 10.2) and raised CRP (OR 4.7, 95% CI 1.7 to 13.1) when compared with virus-negative exacerbations.

INTERPRETATION

Respiratory viruses are commonly detected during pulmonary exacerbations of children with bronchiectasis. HRV-As were the most frequently detected viruses with viral codetection being rare. Time-sequenced cohort studies are needed to determine the role of viral-bacterial interactions in exacerbations of bronchiectasis.

A comparison of two informative SNP-based strategies for typing Pseudomonas aeruginosa isolates from patients with cystic fibrosis

Background

Molecular typing is integral for identifying Pseudomonas aeruginosa strains that may be shared between patients with cystic fibrosis (CF). We conducted a side-by-side comparison of two P. aeruginosa genotyping methods utilising informative-single nucleotide polymorphism (SNP) methods; one targeting 10 P. aeruginosa SNPs and using real-time polymerase chain reaction technology (HRM10SNP) and the other targeting 20 SNPs and based on the Sequenom MassARRAY platform (iPLEX20SNP).

Methods

An in-silico analysis of the 20 SNPs used for the iPLEX20SNP method was initially conducted using sequence type (ST) data on the P. aeruginosa PubMLST website. A total of 506 clinical isolates collected from patients attending 11 CF centres throughout Australia were then tested by both the HRM10SNP and iPLEX20SNP assays. Type-ability and discriminatory power of the methods, as well as their ability to identify commonly shared P. aeruginosa strains, were compared.

Results

The in-silico analyses showed that the 1401 STs available on the PubMLST website could be divided into 927 different 20-SNP profiles (D-value = 0.999), and that most STs of national or international importance in CF could be distinguished either individually or as belonging to closely related single- or double-locus variant groups. When applied to the 506 clinical isolates, the iPLEX20SNP provided better discrimination over the HRM10SNP method with 147 different 20-SNP and 92 different 10-SNP profiles observed, respectively. For detecting the three most commonly shared Australian P. aeruginosa strains AUST-01, AUST-02 and AUST-06, the two methods were in agreement for 80/81 (98.8%), 48/49 (97.8%) and 11/12 (91.7%) isolates, respectively.

Conclusions

The iPLEX20SNP is a superior new method for broader SNP-based MLST-style investigations of P. aeruginosa. However, because of convenience and availability, the HRM10SNP method remains better suited for clinical microbiology laboratories that only utilise real-time PCR technology and where the main interest is detection of the most highly-prevalent P. aeruginosa CF strains within Australian clinics.

Detection of a divergent Parainfluenza 4 virus in an adult patient with influenza like illness using next-generation sequencing

BACKGROUND

Human Parainfluenza viruses are a common cause of both upper and lower respiratory tract infections, particularly in children. Of the four Parainfluenza virus serotypes, Parainfluenza 4 is least well characterised from both the clinical, epidemiological and genetic perspectives.

METHODS

Flocked nose or throat swabs from a previous study investigating viral prevalence in community-based adults suffering from influenza like illness were used as the basis for this study. Samples in which no virus was detected using a 16 viral respiratory pathogen real-time PCR panel were barcoded and pyrosequenced using the Roche 454 GS FLX Titanium chemistry. The sequences were analysed using the VirusHunter bioinformatic pipeline. Sanger sequencing was used to complete the detected Parainfluenza 4 coding region.

RESULTS

A variant Parainfluenza 4 subtype b strain (QLD-01) was discovered in an otherwise healthy adult who presented with influenza like illness. Strain QLD-01 shared genomic similarities with both a and b subtypes. The extent of divergence of this genome from the 5 available whole Parainfluenza 4 genomes impacted the predicted binding efficiencies of the majority of published Parainfluenza 4 PCR assays.

CONCLUSIONS

These findings further support a possible role for Parainfluenza 4 in the aetiology of adult respiratory disease within the community setting, and highlight the caution needed to be used in designing PCR assays from limited sequence information or in using proprietary commercial PCR assays.

Feasibility of parental collected nasal swabs for virus detection in young children with cystic fibrosis

Background

The detrimental role of viruses has been well described in CF, although the pattern of virus infections has not been investigated in a longitudinal study. The primary aim was to determine the feasibility of fortnightly parent collected swabs in young children with CF.

Methods

Children under three years with CF were recruited. Nasal swabs were collected by parents every fortnight and during periods of symptoms over 12 months. Nasal swabs were posted and virus detected using real-time PCR.

Results

Only 27% of the patients completed the study to 10 months, although 98% of the swabs returned were adequate for analysis. Mould was observed growing on 23% of the returned swabs. There was no evidence to demonstrate relationships with symptoms and viruses, prolonged symptoms, prolonged shedding or patterns of virus infections.

Conclusions

This study highlights the need to further investigate the role of viruses in children with CF using a robust method of frequent collection in children for a longitudinal study, with appropriate storage and shipping techniques to avoid mould growth or other potential contaminants.

Epidemiology of respiratory viral infections in children enrolled in a study of influenza vaccine effectiveness

BACKGROUND

Influenza-like illness (ILI) confers a high annual morbidity in young children. We report the epidemiology of ILIs in children who participated in an influenza vaccine effectiveness study during the 2010 Southern Hemisphere influenza season in Sydney, Australia.

METHODS

Children aged 0·5-3 years were prospectively recruited from child care centres (CCCs). We classified them as fully vaccinated, partially vaccinated and unvaccinated according to their receipt of unadjuvanted vaccines containing influenza A (H1N1)pdm09. For 13 weeks commencing 30 July 2010, parents reported when their children developed an ILI (fever ≥37·8°C/feverishness plus ≥1 respiratory symptom) and collected nose and/or throat swabs for multiplex respiratory virus polymerase chain reaction (PCR) testing. Health impacts were assessed by telephone interview at enrolment and two weeks after each ILI.

RESULTS

There were 124 ILIs reported in 105 of 381 enrolled children. Swabs were taken in 117 ILIs: 175 viruses were identified from 103 swabs. Adeno- and rhinoviruses were most frequently identified; 44% of swabs yielded multiple viruses. No virus was associated with more severe symptoms, although rhinovirus-related ILIs lasted longer. Nose swabs had a higher virus detection rate than throat swabs. Influenza-vaccinated children were 1·6 times (P = 0·001) more likely than unvaccinated children to have a non-influenza ILI.

CONCLUSION

Adeno- and rhinoviruses were the most common viruses causing ILI. Swabs taken by parents are an effective method for sample collection. Influenza-like illness was more common in children vaccinated against influenza in this observational study, but prior health-seeking behaviour may have contributed to this difference.

Mailed versus frozen transport of nasal swabs for surveillance of respiratory bacteria in remote Indigenous communities in Australia

Background

Surveillance programs and research for acute respiratory infections in remote Australian communities are complicated by difficulties in the storage and transport of frozen samples to urban laboratories for testing. This study assessed the sensitivity of a simple method for transporting nasal swabs from a remote setting for bacterial polymerase chain reaction (PCR) testing.

Methods

We sampled every individual who presented to a remote community clinic over a three week period in August at a time of low influenza and no respiratory syncytial virus activity. Two anterior nasal swabs were collected from each participant. The left nare specimen was mailed to the laboratory via routine postal services. The right nare specimen was transported frozen. Testing for six bacterial species was undertaken using real-time PCR.

Results

One hundred and forty participants were enrolled who contributed 150 study visits and paired specimens for testing. Respiratory illnesses accounted for 10% of the reasons for presentation. Bacteria were identified in 117 (78%) presentations for 110 (79.4%) individuals; Streptococcus pneumoniae and Haemophilus influenzae were the most common (each identified in 58% of episodes). The overall sensitivity for any bacterium detected in mailed specimens was 82.2% (95% CI 73.6, 88.1) compared to 94.8% (95% CI 89.4, 98.1) for frozen specimens. The sensitivity of the two methods varied by species identified.

Conclusion

The mailing of unfrozen nasal specimens from remote communities appears to influence the utility of the specimen for bacterial studies, with a loss in sensitivity for the detection of any species overall. Further studies are needed to confirm our finding and to investigate the possible mechanisms of effect.

Clinical trial registration

Australia and New Zealand Clinical Trials Registry Number: ACTRN12609001006235.

A single dose of azithromycin does not improve clinical outcomes of children hospitalised with bronchiolitis: a randomised, placebo-controlled trial

Objective

Bronchiolitis, one of the most common reasons for hospitalisation in young children, is particularly problematic in Indigenous children. Macrolides may be beneficial in settings where children have high rates of nasopharyngeal bacterial carriage and frequent prolonged illness. The aim of our double-blind placebo-controlled randomised trial was to determine if a large single dose of azithromycin (compared to placebo) reduced length of stay (LOS), duration of oxygen (O₂) and respiratory readmissions within 6 months of children hospitalised with bronchiolitis. We also determined the effect of azithromycin on nasopharyngeal microbiology.

Methods

Children aged ≤18 months were randomised to receive a single large dose (30 mg/kg) of either azithromycin or placebo within 24 hrs of hospitalisation. Nasopharyngeal swabs were collected at baseline and 48hrs later. Primary endpoints (LOS, O₂) were monitored every 12 hrs. Hospitalised respiratory readmissions 6-months post discharge was collected.

Results

97 children were randomised (n = 50 azithromycin, n = 47 placebo). Median LOS was similar in both groups; azithromycin = 54 hours, placebo = 58 hours (difference between groups of 4 hours 95%CI -8, 13, p = 0.6). O₂ requirement was not significantly different between groups; Azithromycin = 35 hrs; placebo = 42 hrs (difference 7 hours, 95%CI -9, 13, p = 0.7). Number of children re-hospitalised was similar 10 per group (OR = 0.9, 95%CI 0.3, 2, p = 0.8). At least one virus was detected in 74% of children. The azithromycin group had reduced nasopharyngeal bacterial carriage (p = 0.01) but no difference in viral detection at 48 hours.

Conclusion

Although a single dose of azithromycin reduces carriage of bacteria, it is unlikely to be beneficial in reducing LOS, duration of O₂ requirement or readmissions in children hospitalised with bronchiolitis. It remains uncertain if an earlier and/or longer duration of azithromycin improves clinical and microbiological outcomes for children. The trial was registered with the Australian and New Zealand Clinical Trials Register. Clinical trials number: ACTRN12608000150347. http://www.anzctr.org.au/TrialSearch.aspx.

Respiratory virus detection in nasopharyngeal aspirate versus bronchoalveolar lavage is dependent on virus type in children with chronic respiratory symptoms

Background

The comparative yield of respiratory virus detection from nasopharyngeal aspirate (NPA) versus bronchoalveolar lavage (BAL) is uncertain. Furthermore, the significance of virus detection and its relationship to lower airway neutrophilic inflammation is poorly studied.

Objectives

To evaluate the sensitivity, specificity and predictive values of NPA for detecting respiratory viruses in BAL; and to determine the relationship between viruses and lower airway neutrophilia in children with non-acute respiratory illness.

Study design

150 paired NPA and BAL samples were obtained from 75 children aged <18 years undergoing flexible bronchoscopy for investigation of chronic respiratory symptoms. Viral studies were performed using polymerase chain reaction (PCR). Cellularity studies were performed on BALs. Diagnostic parameters of NPA compared to BAL and associations between viruses and lower airway %neutrophils were evaluated.

Results

NPA had a higher yield than BAL for detection of any respiratory virus (52 versus 38, respectively). NPA had a high sensitivity (92%) and low specificity (57%) for detecting HRV in BAL with poor kappa agreement value of 0.398 (95% CI 0.218–0.578, p < 0.001). NPA had a fair sensitivity (69%) and good specificity (90.3%) for detecting HAdV on BAL, kappa agreement was 0.561 (95% CI 0.321–0.801, p < 0.001). HAdV positivity on NPA, compared to negativity, was independently associated with heightened airway neutrophilia [mean difference (95% CI): 18 (1,35); p = 0.042].

Conclusions

NPA has a higher yield for respiratory virus detection than BAL, however its diagnostic accuracy is dependent on viral species. Adenovirus positivity is associated with significantly heightened lower airway neutrophilia in children with chronic respiratory symptoms.

The development of chronic cough in children following presentation to a tertiary paediatric emergency department with acute respiratory illness: study protocol for a prospective cohort study

Background

Acute respiratory illness, a leading cause of cough in children, accounts for a substantial proportion of childhood morbidity and mortality worldwide. In some children acute cough progresses to chronic cough (>4 weeks duration), impacting on morbidity and decreasing quality of life. Despite the importance of chronic cough as a cause of substantial childhood morbidity and associated economic, family and social costs, data on the prevalence, predictors, aetiology and natural history of the symptom are scarce. This study aims to comprehensively describe the epidemiology, aetiology and outcomes of cough during and after acute respiratory illness in children presenting to a tertiary paediatric emergency department.

Methods/design

A prospective cohort study of children aged <15 years attending the Royal Children’s Hospital Emergency Department, Brisbane, for a respiratory illness that includes parent reported cough (wet or dry) as a symptom. The primary objective is to determine the prevalence and predictors of chronic cough (≥4 weeks duration) post presentation with acute respiratory illness. Demographic, epidemiological, risk factor, microbiological and clinical data are completed at enrolment. Subjects complete daily cough dairies and weekly follow-up contacts for 28(±3) days to ascertain cough persistence. Children who continue to cough for 28 days post enrolment are referred to a paediatric respiratory physician for review. Primary analysis will be the proportion of children with persistent cough at day 28(±3). Multivariate analyses will be performed to evaluate variables independently associated with chronic cough at day 28(±3).

Discussion

Our protocol will be the first to comprehensively describe the natural history, epidemiology, aetiology and outcomes of cough during and after acute respiratory illness in children. The results will contribute to studies leading to the development of evidence-based clinical guidelines to improve the early detection and management of chronic cough in children during and after acute respiratory illness.

Evidence of false-positive results in a commercially available rotavirus assay in the vaccine era, Australia, 2011 to 2012

Concerns were raised about specificity of the VIKIA Rota-Adeno immunochromatographic kit. Only 28-37% of samples positive with the VIKIA kit could be confirmed using two real-time RT-PCR assays and three ELISA kits. On re-analysis of a subset of the positive samples, 86% remained positive with the VIKIA kit, however, 90% remained negative in the other assays. In a highly vaccinated population we found a high number of false-positive rotavirus tests with a widely-used commercial kit.

Detection of novel polyomaviruses, TSPyV, HPyV6, HPyV7, HPyV9 and MWPyV in feces, urine, blood, respiratory swabs and cerebrospinal fluid

Eight novel human polyomaviruses have been discovered since 2007. Prevalence rates and tissue tropism for the most recent members HPyV 6, 7, 9, TSPyV and MWPyV are largely unknown. We used real-time PCR to determine the presence of HPyV 6, 7, 9, TSPyV and MWPyV in feces (n = 263), urine (n = 189), blood (n = 161), respiratory swabs (n = 1385) and cerebrospinal fluid (n = 171) from both healthy control children and children and adults undergoing diagnostic testing. Whole genome sequencing was able to be performed on 9 MWPyV positive specimens. Novel polyomaviruses were only detected in respiratory swabs and feces, with no detections of HPyV 9 in any sample type. MWPyV was found to be the most prevalent novel polyomavirus, being detected in 18 (1.5%) respiratory specimens from symptomatic patients, 16 (9.8%) respiratory sample from healthy control children, 11 (5.9%) fecal specimens from patient suffering gastrointestinal illness, and in 13 (15.3%) of feces from healthy control children. MWPyV was found only in respiratory and fecal specimens from children, the oldest being 9 years old. HPyV 6, 7, 9 and TSPyV were also detected in respiratory specimens and fecal specimens at low prevalence (<1.3%). The majority of these detections were found in immunocompromised patients. Our findings suggest that MWPyV can result in a subclinical infection, persistent or intermittent shedding, particularly in young children. The other novel polyomaviruses were also found in respiratory and fecal specimens, but at lower prevalence and most commonly in immunocompromised individuals.

Community-wide, contemporaneous circulation of a broad spectrum of human rhinoviruses in healthy Australian preschool-aged children during a 12-month period

Human rhinovirus (HRV) replication triggers exacerbation of asthma and causes most acute respiratory illnesses (ARIs), which may manifest as influenza-like illness. The recent assignment of 60 previously unknown HRV types to a third HRV species, Human rhinovirus C, raised questions about the prevalence of these picornavirus types in the community, the extent of HRV diversity at a single site, and whether the HRVs have an equally diverse clinical impact on their hosts. We quantified HRV diversity, and there was no clinical impact attributable to HRV species and genotypes among a community population of preschool-aged children with ARI who provided respiratory samples during 2003. All HRV species were represented among 138 children with ARI, and 74 distinct HRV types were cocirculating. Fever accompanied 32.8% of HRV-positive ARI cases. HRVs were less likely than DNA viruses to be codetected with another virus, suggesting virus interference at the community level, demonstrated by the inverse correlation between influenza virus detection and HRV detection.

The influence of target population on nonculture-based detection of markers of Neisseria gonorrhoeae antimicrobial resistance

BACKGROUND

With treatment options for gonorrhoea (Neisseria gonorrhoeae) diminishing, strengthening antimicrobial resistance (AMR) surveillance is paramount.

METHODS

In this study, we investigated polymerase chain reaction (PCR) based methods, in parallel with N. gonorrhoeae multi-antigen sequence typing (NG-MAST), for direct detection of four N. gonorrhoeae chromosomal mechanisms associated with emerging resistance to extended spectrum cephalosporins using noncultured samples: an adenine deletion in the mtrR promoter, a mosaic penicillin-binding protein (PBP) 2, an A501V PBP2 mutation, and alterations at positions 120 and 121 of the porB protein. The PCR assays were validated using a panel of characterised N. gonorrhoeae isolates (n=107) and commensal Neisseria (n=100) species. These PCR assays with NG-MAST were then applied to noncultured clinical specimens from distinct populations in Australia with differing levels of N. gonorrhoeae AMR: the Northern Territory (NT), where resistance has a low population prevalence, and Queensland (Qld), with higher AMR prevalence.

RESULTS

The real-time PCR assays proved highly sensitive and specific. When applied to the noncultured samples, only 1 out of 50 (2%) samples from NT harboured a resistant mechanism, whereas the Qld samples (n=129) collected over different periods showed progressive acquisition of resistant mechanisms, and these were associated with specific NG-MAST types, including Type 225.

CONCLUSIONS

The results suggest that our PCR-based methods could be used to rapidly pinpoint incursion of resistant strains into previously unaffected populations. Likewise, our results show that for molecular AMR surveillance, the population being investigated is as important as the genetic mechanisms being targeted.

Polymerase chain reaction-based screening for the ceftriaxone-resistant Neisseria gonorrhoeae F89 strain

Emergence and spread of Neisseria gonorrhoeae resistant to extended spectrum cephalosporins is a major problem threatening treatment of gonorrhoea and is further highlighted by the recent report of a second ceftriaxone-resistant N. gonorrhoeae strain (F89) in Europe, initially observed in France and subsequently identified in Spain. N. gonorrhoeae antimicrobial resistance (AMR) surveillance has acquired new importance and molecular tools have the potential to enhance bacterial culture-based methods. In this study, we established a polymerase chain reaction (PCR) protocol for direct detection of the F89 strain. A key component of this screening protocol was the development of a hybridisation probe-based melting curve analysis assay (mosaic501-hybPCR) to detect the presence of an A501P substitution on the N. gonorrhoeae mosaic penicillin binding protein 2 (PBP2) sequence, an important characteristic of the F89 strain. The mosaic501-hybPCR was evaluated using plasmid-derived positive controls (n=3) and characterised gonococcal (n=33) and non-gonococcal (n=58) isolates. The protocol was then applied to 159 clinical specimens from Sydney, Australia, collected during the first half of the year 2012 that were N. gonorrhoeae PCR-positive. Overall, the results indicate that the PCR-based protocol is suitable for direct detection of the N. gonorrhoeae F89 strain in non-cultured clinical samples. It therefore provides an additional tool to aid investigations into the potential spread of F89 strain throughout Europe and elsewhere.

Association of micropapillary urothelial carcinoma of the bladder and BK viruria in kidney transplant recipients

INTRODUCTION

BK virus (BKV) is an ubiquitous human polyomavirus that establishes latency in urothelium. BKV is known to re-activate in immunosuppressed individuals, and is an increasingly important cause of nephropathy and graft loss in kidney transplant recipients. Animal studies have demonstrated BKV has a potential role as a tumor virus. However, its role in precipitating or facilitating oncogenesis in humans is still debated.

REPORT

We report 2 cases of aggressive micropapillary urothelial carcinoma of the bladder in kidney transplant recipients with persistent BK viruria and preserved graft function.

RESULTS

In both cases, polyomavirus immunohistochemistry performed on the tumor specimens was strongly positive, and limited to the malignant tissue. BKV DNA, viral protein 1, and large T antigen mRNA were detected in the tumor; however, no viral particles were seen on electron microscopy.

CONCLUSION

In one of the cases, BKV integration into the host genome was identified, leading to the truncation of the major viral capsid gene. This finding raises the concern that persisting BK viruria may be a risk factor for this aggressive form of bladder cancer. Further studies to determine screening and management strategies are required.

Bronchiectasis exacerbation study on azithromycin and amoxycillin-clavulanate for respiratory exacerbations in children (BEST-2): study protocol for a randomized controlled trial

BACKGROUND

Bronchiectasis unrelated to cystic fibrosis (CF) is being increasingly recognized in children and adults globally, both in resource-poor and in affluent countries. However, high-quality evidence to inform management is scarce. Oral amoxycillin-clavulanate is often the first antibiotic chosen for non-severe respiratory exacerbations, because of the antibiotic-susceptibility patterns detected in the respiratory pathogens commonly associated with bronchiectasis. Azithromycin has a prolonged half-life, and with its unique anti-bacterial, immunomodulatory, and anti-inflammatory properties, presents an attractive alternative. Our proposed study will test the hypothesis that oral azithromycin is non-inferior (within a 20% margin) to amoxycillin-clavulanate at achieving resolution of non-severe respiratory exacerbations by day 21 of treatment in children with non-CF bronchiectasis.

METHODS

This will be a multicenter, randomized, double-blind, double-dummy, placebo-controlled, parallel group trial involving six Australian and New Zealand centers. In total, 170 eligible children will be stratified by site and bronchiectasis etiology, and randomized (allocation concealed) to receive: 1) azithromycin (5 mg/kg daily) with placebo amoxycillin-clavulanate or 2) amoxycillin-clavulanate (22.5 mg/kg twice daily) with placebo azithromycin for 21 days as treatment for non-severe respiratory exacerbations. Clinical data and a parent-proxy cough-specific quality of life (PC-QOL) score will be obtained at baseline, at the start and resolution of exacerbations, and on day 21. In most children, blood and deep-nasal swabs will also be collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 21. The main secondary outcome is the PC-QOL score. Other outcomes are: time to next exacerbation; requirement for hospitalization; duration of exacerbation, and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood inflammatory markers will be reported where available.

DISCUSSION

Currently, there are no published randomized controlled trials (RCT) to underpin effective, evidence-based management of acute respiratory exacerbations in children with non-CF bronchiectasis. To help address this information gap, we are conducting two RCTs. The first (bronchiectasis exacerbation study; BEST-1) evaluates the efficacy of azithromycin and amoxycillin-clavulanate compared with placebo, and the second RCT (BEST-2), described here, is designed to determine if azithromycin is non-inferior to amoxycillin-clavulanate in achieving symptom resolution by day 21 of treatment in children with acute respiratory exacerbations.

TRIAL REGISTRATION

Australia and New Zealand Clinical Trials Register (ANZCTR) number http://ACTRN12612000010897. http://www.anzctr.org.au/trial_view.aspx?id=347879.

High-throughput single-nucleotide polymorphism-based typing of shared Pseudomonas aeruginosa strains in cystic fibrosis patients using the Sequenom iPLEX platform

Shared strains of Pseudomonas aeruginosa are now well recognized in people with cystic fibrosis (CF), and suitable P. aeruginosa laboratory typing tools are pivotal to understanding their clinical significance and guiding infection control policies in CF clinics. We therefore compared a single-nucleotide polymorphism (SNP)-based typing method using Sequenom iPLEX matrix-assisted laser desorption ionization with time-of-flight mass spectrometry (MALDI-TOF MS) with typing methods used routinely by our laboratory. We analysed 617 P. aeruginosa isolates that included 561 isolates from CF patients collected between 2001 and 2009 in two Brisbane CF clinics and typed previously by enterobacterial repetitive intergenic consensus (ERIC)-PCR, as well as 56 isolates from non-CF patients analysed previously by multilocus sequence typing (MLST). The isolates were tested using a P. aeruginosa Sequenom iPLEX MALDI-TOF (PA iPLEX) method comprising two multiplex reactions, a 13-plex and an 8-plex, to characterize 20 SNPs from the P. aeruginosa housekeeping genes acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. These 20 SNPs were employed previously in a real-time format involving 20 separate assays in our laboratory. The SNP analysis revealed 121 different SNP profiles for the 561 CF isolates. Overall, there was at least 96% agreement between the ERIC-PCR and SNP analyses for all predominant shared strains among patients attending our CF clinics: AUST-01, AUST-02 and AUST-06. For the less frequently encountered shared strain AUST-07, 6/25 (24%) ERIC-PCR profiles were misidentified initially as AUST-02 or as unique, illustrating the difficulty of gel-based analyses. SNP results for the 56 non-CF isolates were consistent with previous MLST data. Thus, the PA iPLEX format provides an attractive high-throughput alternative to ERIC-PCR for large-scale investigations of shared P. aeruginosa strains.

Human rhinovirus C in adult haematopoietic stem cell transplant recipients with respiratory illness

Background

A previously unidentified species of human rhinovirus, HRV-C, was described in 2006 in association with lower respiratory tract infection (LRTI). Features of infection in immunosuppressed adults are poorly characterised.

Objectives

This study aims to determine the epidemiology of HRV-C in haematopoietic stem cell transplant (HSCT) recipients in a single centre.

Study design

A prospective cohort study of all HSCT recipients admitted to Westmead Hospital, Westmead, Australia from 1 July 2005 to 30 September 2007 was undertaken. Nose/throat samples were collected from all patients at the time of admission and patients developing pre-defined symptoms and/or signs of respiratory infection during the admission. Samples were processed and tested for rhinoviruses and 14 other respiratory viruses using nucleic acid-based methods, immunofluorescence and culture. HRV genotyping was performed by sequencing a region of the rhinovirus 5′ untranslated region (UTR). Clinical data on each episode were collected prospectively.

Results

HRVs were identified in 24 episodes: 8% of 299 episodes of clinically- defined respiratory infections and 39% of 61 episodes in which respiratory viruses were detected. HRV-C was most frequent (HRV-C: nine, HRV-A: eight and HRV-B: two). Seven episodes of HRV-C, five with pneumonia, occurred within 100 days of HSCT. Co-pathogens were frequent.

Conclusions

The newly described HRV-C was the most common rhinovirus group detected in HSCT recipients with respiratory infection, with co-pathogens being frequent. Further research is required to understand the activity and pathogenicity of this virus in HSCT recipients.

Protocol for the molecular detection of antibiotic resistance mechanisms in Neisseria gonorrhoeae

Gonorrhoea is no longer an easily treatable ailment but rather is now a challenging disease in terms of antimicrobial resistance (AMR) with treatment options rapidly diminishing. The causative agent of gonorrhoea, Neisseria gonorrhoeae, has managed to develop resistance to almost every single drug used against it with the sole exception of extended spectrum cephalosporins. The situation is further exacerbated by the fact that not only are the rates of gonococcal infections on a steady rise globally, but tracking AMR is being undermined by the growing popularity of molecular methods at the expense of traditional bacterial culture in diagnostic laboratories. Recently, concerns have been raised over the emergence of a multi-resistant gonococci and the potential for untreatable gonorrhoea. Maintaining optimal epidemiological surveillance of gonococcal AMR remains an important aspect of gonorrhoea control. The development of molecular tools for tracking AMR in N. gonorrhoeae has the potential to further enhance such surveillance. In this chapter, we discuss nucleic acid amplification-based detection of AMR in gonorrhoea with a particular emphasis on chromosomal-mediated resistance to beta-lactam antibiotics.

Real-time PCR genotyping of Neisseria gonorrhoeae isolates using 14 informative single nucleotide polymorphisms on gonococcal housekeeping genes

OBJECTIVES

Neisseria gonorrhoeae multilocus sequence typing (MLST) is a key tool used to investigate the macroepidemiology of gonococci exhibiting antimicrobial resistance (AMR). However, the utility of MLST is undermined by the high workload and cost associated with DNA sequencing of seven housekeeping genes. In this study, we investigated single nucleotide polymorphism (SNP)-based profiling as a means of circumventing these problems.

METHODS

A total of 14 SNPs were selected following in silico analysis of available N. gonorrhoeae MLST sequence data. Real-time PCR methods were developed for characterization of each SNP and applied to 86 N. gonorrhoeae isolates exhibiting a range of ceftriaxone MICs. Twenty-one isolates had previously been characterized by MLST. The ability of the real-time PCR methods to generate SNP profiles and of the 14 SNP profiles to predict MLST types were assessed.

RESULTS

In silico analysis of the 217 different MLST types available on the Neisseria web site showed 181 different 14 SNP profiles (Simpson's index of diversity = 0.998). When the real-time PCR methods were applied to the isolates, 29 different 14 SNP profiles were obtained for 83 isolates. Predicted MLST types were consistent with those for the 21 isolates previously characterized by MLST. For 46 isolates with raised ceftriaxone MICs (≥ 0.03 mg/L), there were 14 different 14 SNP profiles observed, with two profiles accounting for more than half of these isolates.

CONCLUSIONS

The 14 SNP real-time PCR profiling approach is a simple and cost-effective alternative to N. gonorrhoeae MLST and could be used to complement current typing schemes in N. gonorrhoeae AMR investigations.

The ticking time bomb: escalating antibiotic resistance in Neisseria gonorrhoeae is a public health disaster in waiting

From a once easily treatable infection, gonorrhoea has evolved into a challenging disease, which in future may become untreatable in certain circumstances. International spread of extensively drug-resistant gonococci would have severe public health implications. It seems clear that under the current treatment pressure from extended-spectrum cephalosporins, and owing to Neisseria gonorrhoeae's remarkable evolutionary adaptability, further rise of ceftriaxone-resistant strains around the world is inevitable. Simply increasing the doses of extended-spectrum cephalosporins will likely prove ineffective in the long run, and has been a lesson learnt for all single-agent therapies used for gonorrhoea to date. We recommend that dual therapy, especially those consisting of extended-spectrum cephalosporins and azithromycin, be adopted more widely and complemented by strengthening of antimicrobial resistance surveillance. Unless there is urgent action at international and local levels to combat the problem of N. gonorrhoeae antimicrobial resistance, we are in for gloomy times ahead in terms of gonorrhoea disease and control.

Antibiotics for bronchiectasis exacerbations in children: rationale and study protocol for a randomised placebo-controlled trial

BACKGROUND

Despite bronchiectasis being increasingly recognised as an important cause of chronic respiratory morbidity in both indigenous and non-indigenous settings globally, high quality evidence to inform management is scarce. It is assumed that antibiotics are efficacious for all bronchiectasis exacerbations, but not all practitioners agree. Inadequately treated exacerbations may risk lung function deterioration. Our study tests the hypothesis that both oral azithromycin and amoxicillin-clavulanic acid are superior to placebo at improving resolution rates of respiratory exacerbations by day 14 in children with bronchiectasis unrelated to cystic fibrosis.

METHODS

We are conducting a bronchiectasis exacerbation study (BEST), which is a multicentre, randomised, double-blind, double-dummy, placebo-controlled, parallel group trial, in five centres (Brisbane, Perth, Darwin, Melbourne, Auckland). In the component of BEST presented here, 189 children fulfilling inclusion criteria are randomised (allocation-concealed) to receive amoxicillin-clavulanic acid (22.5 mg/kg twice daily) with placebo-azithromycin; azithromycin (5 mg/kg daily) with placebo-amoxicillin-clavulanic acid; or placebo-azithromycin with placebo-amoxicillin-clavulanic acid for 14 days. Clinical data and a paediatric cough-specific quality of life score are obtained at baseline, at the start and resolution of exacerbations, and at day 14. In most children, blood and deep nasal swabs are also collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 14. The main secondary outcome is the paediatric cough-specific quality of life score. Other outcomes are time to next exacerbation; requirement for hospitalisation; duration of exacerbation; and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood markers will also be reported.

DISCUSSION

Effective, evidence-based management of exacerbations in people with bronchiectasis is clinically important. Yet, there are few randomised controlled trials (RCTs) in the neglected area of non-cystic fibrosis bronchiectasis. Indeed, no published RCTs addressing the treatment of bronchiectasis exacerbations in children exist. Our multicentre, double-blind RCT is designed to determine if azithromycin and amoxicillin-clavulanic acid, compared with placebo, improve symptom resolution on day 14 in children with acute respiratory exacerbations. Our planned assessment of the predictors of antibiotic response, the role of antibiotic-resistant respiratory pathogens, and whether early treatment with antibiotics affects duration and time to the next exacerbation, are also all novel.

TRIAL REGISTRATION

Australia and New Zealand Clinical Trials Register (ANZCTR) number ACTRN12612000011886.

Exploring the prevalence of ten polyomaviruses and two herpes viruses in breast cancer

Several different viruses have been proposed to play a role in breast carcinogenesis. The aim of this study was to investigate the prevalence of a subset of viruses in breast cancer tissue. We investigated the prevalence of 12 DNA viruses: EBV and CMV from the Herpesviridae family and SV40, BKV, JCV, MCV, WUV, KIV, LPV, HPyV6, HPyV7, and TSV from the Polyomaviridae family in 54 fresh frozen breast tumour specimens. Relevant clinical data and basic lifestyle data were available for all patients. The tissue samples were DNA extracted and real-time PCR assays were used for viral detection.The highest prevalence, 10% (5/54), was found for EBV. MCV, HPyV6, and HPyV7 were detected in single patient samples (2% each), while WUV, KIV, JCV, BKV, LPV, SV40, TSV and CMV were not detected in the 54 breast cancer specimens analysed here. Further investigations are needed to elucidate the potential role of viruses, and particularly EBV, in breast carcinogenesis.