Innovations in genomic antimicrobial resistance surveillance

Whole-genome sequencing of antimicrobial-resistant pathogens is increasingly being used for antimicrobial resistance (AMR) surveillance, particularly in high-income countries. Innovations in genome sequencing and analysis technologies promise to revolutionise AMR surveillance and epidemiology; however, routine adoption of these technologies is challenging, particularly in low-income and middle-income countries. As part of a wider series of workshops and online consultations, a group of experts in AMR pathogen genomics and computational tool development conducted a situational analysis, identifying the following under-used innovations in genomic AMR surveillance: clinical metagenomics, environmental metagenomics, gene or plasmid tracking, and machine learning. The group recommended developing cost-effective use cases for each approach and mapping data outputs to clinical outcomes of interest to justify additional investment in capacity, training, and staff required to implement these technologies. Harmonisation and standardisation of methods, and the creation of equitable data sharing and governance frameworks, will facilitate successful implementation of these innovations.

SARS-CoV-2 Outbreak Investigation Using Contact Tracing and Whole-Genome Sequencing in an Ontario Tertiary Care Hospital

Genomic epidemiology can facilitate an understanding of evolutionary history and transmission dynamics of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak. We used next-generation sequencing techniques to study SARS-CoV-2 genomes isolated from patients and health care workers (HCWs) across five wards of a Canadian hospital with an ongoing SARS-CoV-2 outbreak. Using traditional contact tracing methods, we show transmission events between patients and HCWs, which were also supported by the SARS-CoV-2 lineage assignments. The outbreak predominantly involved SARS-CoV-2 B.1.564.1 across all five wards, but we also show evidence of community introductions of lineages B.1, B.1.1.32, and B.1.231, falsely assumed to be outbreak related. Altogether, our study exemplifies the value of using contact tracing in combination with genomic epidemiology to understand the transmission dynamics and genetic underpinnings of a SARS-CoV-2 outbreak. IMPORTANCE Our manuscript describes a SARS-CoV-2 outbreak investigation in an Ontario tertiary care hospital. We use traditional contract tracing paired with whole-genome sequencing to facilitate an understanding of the evolutionary history and transmission dynamics of this SARS-CoV-2 outbreak in a clinical setting. These advancements have enabled the incorporation of phylogenetics and genomic epidemiology into the understanding of clinical outbreaks. We show that genomic epidemiology can help to explore the genetic evolution of a pathogen in real time, enabling the identification of the index case and helping understand its transmission dynamics to develop better strategies to prevent future spread of SARS-CoV-2 in congregate, clinical settings such as hospitals.

Identification of a broadly conserved family of enzymes that hydrolyze (p)ppApp

Bacteria produce a variety of nucleotide second messengers to adapt to their surroundings. Although chemically similar, the nucleotides guanosine penta- and tetraphosphate [(p)ppGpp] and adenosine penta- and tetraphosphate [(p)ppApp] have distinct functions in bacteria. (p)ppGpp mediates survival under nutrient-limiting conditions and its intracellular levels are regulated by synthetases and hydrolases belonging to the RelA-SpoT homolog (RSH) family of enzymes. By contrast, (p)ppApp is not known to be involved in nutrient stress responses and is synthesized by RSH-resembling toxins that inhibit the growth of bacterial cells. However, it remains unclear whether there exists a family of hydrolases that specifically act on (p)ppApp to reverse its toxic effects. Here, we present the structure and biochemical characterization of adenosine 3'-pyrophosphohydrolase 1 (Aph1), the founding member of a monofunctional (p)ppApp hydrolase family of enzymes. Our work reveals that Aph1 adopts a histidine-aspartate (HD)-domain fold characteristic of phosphohydrolase metalloenzymes and its activity mitigates the growth inhibitory effects of (p)ppApp-synthesizing toxins. Using an informatic approach, we identify over 2,000 putative (p)ppApp hydrolases that are widely distributed across bacterial phyla and found in diverse genomic contexts, and we demonstrate that 12 representative members hydrolyze ppApp. In addition, our in silico analyses reveal a unique molecular signature that is specific to (p)ppApp hydrolases, and we show that mutation of two residues within this signature broadens the specificity of Aph1 to promiscuously hydrolyze (p)ppGpp in vitro. Overall, our findings indicate that like (p)ppGpp hydrolases, (p)ppApp hydrolases are widespread in bacteria and may play important and underappreciated role(s) in bacterial physiology.

GloveCare: a pilot study in preparation for a cluster crossover randomized controlled trial of non-sterile glove-based care in preventing late-onset infection in the NICU

BACKGROUND

Late-onset infections (LOI) are a major cause of morbidity and mortality among patients in the neonatal intensive care unit (NICU). Gloving after hand hygiene may be a pragmatic approach to prevent infections that arise when healthcare workers' hands transmit pathogens to neonates.

OBJECTIVE

To determine the feasibility of conducting a multicenter, open-labeled randomized controlled trial (RCT) to determine whether a protocol that requires healthcare workers (HCWs) in a level 3 NICU to wear non-sterile gloves plus hand hygiene reduces the occurrence of a late-onset infection, compared to hand hygiene alone.

METHODS

In this single-center pilot study, we recruited neonates admitted to the McMaster Children's Hospital NICU from June 2017 to May 2018. The NICU was randomized to begin with the standard (control) arm for 6 months (June 2017 to Dec 2017), followed by the gloving (GloveCare) arm for 6 months (Jan 2018 to July 2018), with a 2-week washout period in-between to educate healthcare workers about gloving. We measured numerous feasibility outcomes including enrollment, event rate, and compliance with hand hygiene (Moment 1: before patient contact, Moment 2: before clean procedure, Moment 3: after body fluid contact, Moment 4: after patient contact) and gloving compliance.

RESULTS

We enrolled 750 neonates (390 Standard care, 360 GloveCare) and achieved 100% enrollment. We found higher hand hygiene compliance during the standard care arm compared to the GloveCare for all four moments of hand hygiene (Moment 1: 87% vs 79%, OR=1.86 (1.34, 2.59); Moment 2: OR=1.73 (1.00, 3.01); Moment 3: OR=1.11 (0.62, 1.98); Moment 4: OR=1.65 (1.27, 2.14)). We developed and validated a method to calculate glove compliance, which ranged from 48 to 85%, and was highest for moment 3 (doffing after a procedure or body fluid exposure risk). No adverse events were documented for patients or staff.

DISCUSSION

Reduction in hand hygiene compliance in the GloveCare arm presents a pragmatic challenge in ascertaining the effectiveness of gloving to prevent LOI. Most LOIs were non-sterile-site infections, which is considered a less patient-important or clinically relevant outcome compared to sterile-site LOI. Ensuring efficient collection and validation of hand hygiene and gloving data is imperative.

CONCLUSION

The pilot study demonstrated the feasibility of this intervention though modifications to improve hand hygiene compliance during GloveCare will be important prior to a multicenter cluster RCT to assess the efficacy of non-sterile glove-based care in preventing LOI in the NICU.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03078335.

Nanopore-only assemblies for genomic surveillance of the global priority drug-resistant pathogen, Klebsiella pneumoniae

Oxford Nanopore Technologies (ONT) sequencing has rich potential for genomic epidemiology and public health investigations of bacterial pathogens, particularly in low-resource settings and at the point of care, due to its portability and affordability. However, low base-call accuracy has limited the reliability of ONT data for critical tasks such as antimicrobial resistance (AMR) and virulence gene detection and typing, serotype prediction, and cluster identification. Thus, Illumina sequencing remains the standard for genomic surveillance despite higher capital and running costs. We tested the accuracy of ONT-only assemblies for common applied bacterial genomics tasks (genotyping and cluster detection, implemented via Kleborate, Kaptive and Pathogenwatch), using data from 54 unique Klebsiella pneumoniae isolates. ONT reads generated via MinION with R9.4.1 flowcells were basecalled using three alternative models [Fast, High-accuracy (HAC) and Super-accuracy (SUP), available within ONT's Guppy software], assembled with Flye and polished using Medaka. Accuracy of typing using ONT-only assemblies was compared with that of Illumina-only and hybrid ONT+Illumina assemblies, constructed from the same isolates as reference standards. The most resource-intensive ONT-assembly approach (SUP basecalling, with or without Medaka polishing) performed best, yielding reliable capsule (K) type calls for all strains (100 % exact or best matching locus), reliable multi-locus sequence type (MLST) assignment (98.3 % exact match or single-locus variants), and good detection of acquired AMR genes and mutations (88-100 % correct identification across the various drug classes). Distance-based trees generated from SUP+Medaka assemblies accurately reflected overall genetic relationships between isolates. The definition of outbreak clusters from ONT-only assemblies was problematic due to inflation of SNP counts by high base-call errors. However, ONT data could be reliably used to 'rule out' isolates of distinct lineages from suspected transmission clusters. HAC basecalling + Medaka polishing performed similarly to SUP basecalling without polishing. Therefore, we recommend investing compute resources into basecalling (SUP model), wherever compute resources and time allow, and note that polishing is also worthwhile for improved performance. Overall, our results show that MLST, K type and AMR determinants can be reliably identified with ONT-only R9.4.1 flowcell data. However, cluster detection remains challenging with this technology.

Canadian Paediatric and Perinatal HIV/AIDS Research Group consensus recommendations for infant feeding in the HIV context

Background:

Providing comprehensive infant feeding guidance to families affected by HIV is complex and requires a multidisciplinary approach. While exclusive formula feeding remains the preferred recommendation for infants born to women living with HIV (WLWH) in high-income countries, a more nuanced approach that may include the option of breastfeeding under certain circumstances is emerging in many resource-rich countries.

Methods:

The Canadian Paediatric & Perinatal HIV/AIDS Research Group (CPARG) hosted a Canadian Institute of Health Research-funded meeting in 2016 to develop consensus among multidisciplinary providers around counselling and recommendations for infant feeding. After presentations by adult and pediatric health care providers, basic scientists, and community-based researchers, a subgroup drafted summary evidence-informed recommendations. Along with revisions among CPARG members, a community review was performed by a convenience sample of WLWH who had given birth in the past 5 years from Ontario and Quebec. A legal review was also conducted to ensure understanding of the criminalization potential and concern of HIV transmission and exposure.

Results:

The Canadian consensus guidelines continue to support formula feeding as the preferred method of infant feeding as it eliminates any residual risk of postnatal vertical transmission. Formula should be made available for all infants born to mothers living with HIV for their first year of life. A comprehensive approach to counselling WLWH is outlined to assist providers to effectively counsel on current evidence to ensure WLWH are fully informed in their decision making. For women meeting criteria to and elect to breastfeed, frequent maternal virologic monitoring, and follow-up is required of both mother and infant. Antiretroviral prophylaxis and monitoring are recommended for breastfed infants. The community review highlighted the importance of other supports and counselling needed for implementing effective formula feeding, aside from access to formula. The legal review provided clarifying language around child protection services involvement and the need to provide referral to legal resources or information upon request. Surveillance systems to monitor for cases of breastmilk transmission should be in place to improve gaps in care and develop further knowledge in this area.

Conclusion:

The Canadian infant feeding consensus guideline is designed to inform and enable better care for WLWH and their babies. Ongoing evaluation of these guidelines as new evidence emerges will be important.

CARD 2023: expanded curation, support for machine learning, and resistome prediction at the Comprehensive Antibiotic Resistance Database

The Comprehensive Antibiotic Resistance Database (CARD; card.mcmaster.ca) combines the Antibiotic Resistance Ontology (ARO) with curated AMR gene (ARG) sequences and resistance-conferring mutations to provide an informatics framework for annotation and interpretation of resistomes. As of version 3.2.4, CARD encompasses 6627 ontology terms, 5010 reference sequences, 1933 mutations, 3004 publications, and 5057 AMR detection models that can be used by the accompanying Resistance Gene Identifier (RGI) software to annotate genomic or metagenomic sequences. Focused curation enhancements since 2020 include expanded β-lactamase curation, incorporation of likelihood-based AMR mutations for Mycobacterium tuberculosis, addition of disinfectants and antiseptics plus their associated ARGs, and systematic curation of resistance-modifying agents. This expanded curation includes 180 new AMR gene families, 15 new drug classes, 1 new resistance mechanism, and two new ontological relationships: evolutionary_variant_of and is_small_molecule_inhibitor. In silico prediction of resistomes and prevalence statistics of ARGs has been expanded to 377 pathogens, 21,079 chromosomes, 2,662 genomic islands, 41,828 plasmids and 155,606 whole-genome shotgun assemblies, resulting in collation of 322,710 unique ARG allele sequences. New features include the CARD:Live collection of community submitted isolate resistome data and the introduction of standardized 15 character CARD Short Names for ARGs to support machine learning efforts.

A survey on Canadian pediatric hospital clinical/medical teaching unit implementation during the first and second wave of the COVID-19 pandemic

BACKGROUND

As the COVID-19 pandemic heightened, infection control and prevention experts recommended clinical training opportunities be modified or discontinued, substantially impacting the function of clinical or medical teaching units (CTU). A CTU is structured to involve medical learners such that they become active participants of the health care team. Since a review of the literature demonstrates a paucity of data to guide pediatric CTU implementation during pandemic phases, we developed and disseminated a survey to assess Canadian practices.

METHOD

A group of infectious disease specialists and pediatric hospitalists developed, tested, and disseminated surveys to understand CTU clinical rounding and teaching practices during the waves of the COVID-19 pandemic.

RESULT

Our surveys demonstrate the variability in adapting rounding practices during this pandemic and highlights the opportunities to share our approaches and lessons learned to optimize learner experience and patient centered care during unprecedented times in our academic hospitals. We also show the pragmatic implementation of our new pediatric hospital CTU process that was informed by our survey results.

CONCLUSION

Our study demonstrates the variability in adapting rounding practices during this pandemic and highlights the opportunities to share our approaches and lessons learned to optimize learner experience and patient centered care during unprecedented times in our academic hospitals.

Identifying novel β-lactamase substrate activity through in silico prediction of antimicrobial resistance

Diagnosing antimicrobial resistance (AMR) in the clinic is based on empirical evidence and current gold standard laboratory phenotypic methods. Genotypic methods have the potential advantages of being faster and cheaper, and having improved mechanistic resolution over phenotypic methods. We generated and applied rule-based and logistic regression models to predict the AMR phenotype from Escherichia coli and Pseudomonas aeruginosa multidrug-resistant clinical isolate genomes. By inspecting and evaluating these models, we identified previously unknown β-lactamase substrate activities. In total, 22 unknown β-lactamase substrate activities were experimentally validated using targeted gene expression studies. Our results demonstrate that generating and analysing predictive models can help guide researchers to the mechanisms driving resistance and improve annotation of AMR genes and phenotypic prediction, and suggest that we cannot solely rely on curated knowledge to predict resistance phenotypes.

Structural basis for effector transmembrane domain recognition by type VI secretion system chaperones

Type VI secretion systems (T6SSs) deliver antibacterial effector proteins between neighboring bacteria. Many effectors harbor N-terminal transmembrane domains (TMDs) implicated in effector translocation across target cell membranes. However, the distribution of these TMD-containing effectors remains unknown. Here, we discover prePAAR, a conserved motif found in over 6000 putative TMD-containing effectors encoded predominantly by 15 genera of Proteobacteria. Based on differing numbers of TMDs, effectors group into two distinct classes that both require a member of the Eag family of T6SS chaperones for export. Co-crystal structures of class I and class II effector TMD-chaperone complexes from Salmonella Typhimurium and Pseudomonas aeruginosa, respectively, reveals that Eag chaperones mimic transmembrane helical packing to stabilize effector TMDs. In addition to participating in the chaperone-TMD interface, we find that prePAAR residues mediate effector-VgrG spike interactions. Taken together, our findings reveal mechanisms of chaperone-mediated stabilization and secretion of two distinct families of T6SS membrane protein effectors.

CARD 2020: antibiotic resistome surveillance with the comprehensive antibiotic resistance database

The Comprehensive Antibiotic Resistance Database (CARD; https://card.mcmaster.ca) is a curated resource providing reference DNA and protein sequences, detection models and bioinformatics tools on the molecular basis of bacterial antimicrobial resistance (AMR). CARD focuses on providing high-quality reference data and molecular sequences within a controlled vocabulary, the Antibiotic Resistance Ontology (ARO), designed by the CARD biocuration team to integrate with software development efforts for resistome analysis and prediction, such as CARD's Resistance Gene Identifier (RGI) software. Since 2017, CARD has expanded through extensive curation of reference sequences, revision of the ontological structure, curation of over 500 new AMR detection models, development of a new classification paradigm and expansion of analytical tools. Most notably, a new Resistomes & Variants module provides analysis and statistical summary of in silico predicted resistance variants from 82 pathogens and over 100 000 genomes. By adding these resistance variants to CARD, we are able to summarize predicted resistance using the information included in CARD, identify trends in AMR mobility and determine previously undescribed and novel resistance variants. Here, we describe updates and recent expansions to CARD and its biocuration process, including new resources for community biocuration of AMR molecular reference data.

A unified multidisciplinary fragility hip fracture pilot pathway in a trauma centre in Hong Kong: One-year outcome in the acute phase

Introduction:

The growing impact of fragility hip fracture (FHF) on the healthcare system and the society has become a major concern worldwide. A unified multidisciplinary FHF pathway from admission to rehabilitation and back to community was established in 2015. The acute phase of the pathway was put into pilot in our hospital to evaluate the outcome.

Method:

A designated FHF team was established in our centre since January 2015. The FHF pathway was piloted since June 2015. Patients admitted with a hip fracture resulting from fall on standing height were included. Major outcome parameters were compared in three phases: (1) before FHF team and FHF pathway (January to December 2014), (2) after FHF team but before FHF pathway (January to May 2015) and (3) after FHF team and FHF pathway (June 2015 to May 2016).

Result:

In phases 1, 2 and 3, 631, 263 and 634 patients were included, respectively. From phases 1 to 3, the average key performance indicator (KPI) has improved from 49.2% to 65.8% to 70.0% significantly; average acute length of stay (days) has improved from 13.7 to 13.4 to 11.3 significantly; total surgical complication rates have improved from 6.2% to 7.6% to 5.8%. The 30-day mortality rate and the unplanned readmission rate (within 28 days) have remained below 2.7% and 2.2%, respectively.

Conclusions:

Implementation of an FHF pathway can form a multidisciplinary platform that can improve the standard of care and outcome for our FHF patients in terms of KPI and also length of stay.

New knowledge added by this study:

A newly designed and implemented fragility hip fracture pathway in our centre as a pilot with the results evaluated.

Implications for clinical practice or policy:

With the increasing elderly population in Hong Kong and globally, there is a need to design and implement a fragility hip fracture (FHF) pathway to improve the care and effectiveness for FHF patients.

Micronuclei formation in rainbow trout cells exposed to multiple stressors: Morpholine, heat shock, and ionizing radiation

Discharges from industrial cooling water systems can include low levels of morpholine (a chemical pH regulator and corrosion inhibitor), as well as transiently higher temperature effluent water which present a potential source of environmental impact to aquatic biota. The effects of environmental levels of morpholine or heat shock (HS) treatment alone and in combination with a challenge high-dose of ¹³⁷Cs ionizing radiation were studied using the cytokinesis block micronucleus assay in a rainbow trout cell line (RTG-2). Morpholine treatment of 10 or 100mgL^-1 alone produced no significant effects, and no interaction was observed in combination with 7.75Gy radiation. A 9°C magnitude HS treatment alone significantly increased micronuclei formation. A synergistic response was observed when 9°C HS was combined with 7.75Gy radiation, with 15% more cells containing 3 or more micronuclei than the sum of each individual stressor. A synergistic increase in the average number of micronuclei was observed when morpholine and a 9°C HS were co-treated. These results indicate that morpholine at environmentally-relevant levels does not impact micronuclei formation or cell cycle progression however 9°C HS may be of potential concern both alone and in combination with other stressor treatments.

Antimicrobial resistance surveillance in the genomic age

The loss of effective antimicrobials is reducing our ability to protect the global population from infectious disease. However, the field of antibiotic drug discovery and the public health monitoring of antimicrobial resistance (AMR) is beginning to exploit the power of genome and metagenome sequencing. The creation of novel AMR bioinformatics tools and databases and their continued development will advance our understanding of the molecular mechanisms and threat severity of antibiotic resistance, while simultaneously improving our ability to accurately predict and screen for antibiotic resistance genes within environmental, agricultural, and clinical settings. To do so, efforts must be focused toward exploiting the advancements of genome sequencing and information technology. Currently, AMR bioinformatics software and databases reflect different scopes and functions, each with its own strengths and weaknesses. A review of the available tools reveals common approaches and reference data but also reveals gaps in our curated data, models, algorithms, and data-sharing tools that must be addressed to conquer the limitations and areas of unmet need within the AMR research field before DNA sequencing can be fully exploited for AMR surveillance and improved clinical outcomes.

CARD 2017: expansion and model-centric curation of the comprehensive antibiotic resistance database

The Comprehensive Antibiotic Resistance Database (CARD; http://arpcard.mcmaster.ca) is a manually curated resource containing high quality reference data on the molecular basis of antimicrobial resistance (AMR), with an emphasis on the genes, proteins and mutations involved in AMR. CARD is ontologically structured, model centric, and spans the breadth of AMR drug classes and resistance mechanisms, including intrinsic, mutation-driven and acquired resistance. It is built upon the Antibiotic Resistance Ontology (ARO), a custom built, interconnected and hierarchical controlled vocabulary allowing advanced data sharing and organization. Its design allows the development of novel genome analysis tools, such as the Resistance Gene Identifier (RGI) for resistome prediction from raw genome sequence. Recent improvements include extensive curation of additional reference sequences and mutations, development of a unique Model Ontology and accompanying AMR detection models to power sequence analysis, new visualization tools, and expansion of the RGI for detection of emergent AMR threats. CARD curation is updated monthly based on an interplay of manual literature curation, computational text mining, and genome analysis.

Use of a bioengineered human dermis on a large acute foot ulcer

When there is a lack of available skin, full-thickness wounds are often closed with meshed and expanded split-thickness skin grafts. However, as there is a lack of dermis beneath the healed graft interstices, hypertrophic scarring, wound contraction and instability of the skin may occur. Moreover, some patients may not be suitable for or refuse surgery.

How did general practitioners protect themselves, their family, and staff during the SARS epidemic in Hong Kong?

CONTEXT

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease and how the frontline community doctors respond to it is not known.

OBJECTIVES

To explore the impact of SARS on general practitioners (GPs) in Hong Kong.

DESIGN

A cross sectional survey.

SETTING

Community based primary care clinics.

PARTICIPANTS

183 family medicine tutors affiliated with a local university. Postal survey sent to all tutors with a 74.8% response rate.

MAIN OUTCOME MEASURES

Change of clinical behaviour and practices during the epidemic; anxiety level of primary care doctors.

RESULTS

All agreed SARS had changed their clinical practices. Significant anxiety was found in family doctors. Three quarters of respondents recalled requesting more investigations while a quarter believed they had over-prescribed antibiotics. GPs who were exposed to SARS or who had worked in high infection districts were less likely to quarantine themselves (10.8% versus 33.3%; p<0.01; 6.5% versus 27.5%; p<0.01 respectively). Exposure to SARS, the infection rates in their working district, and anxiety levels had significant impact on the level of protection or prescribing behaviour.

CONCLUSION

The clinical practice of GPs changed significantly as a result of SARS. Yet, those did not quarantine themselves suggesting other factors may have some part to play. As failure to apply isolation precautions to suspected cases of SARS was one major reason for its spread, a contingency plan from the government to support family doctors is of utmost importance. Interface between private and public sectors are needed in Hong Kong to prepare for any future epidemics.

Syntactic awareness of Cantonese-speaking children

The development of metalinguistic awareness, and specifically syntactic awareness, (here measured by age-related changes in the ability to judge and revise unacceptable sentences), reflects developmental changes in focus from semantic to syntactic properties of sentences. Previous research reported that children find judgements of word-order changes easier than morphological violations (Hakes, 1980). We hypothesized that this difference in ease of judgement is linked to the language under investigation. That is, there may be a relationship between the functional load of grammatical morphemes and ability to detect syntactic violations. This study investigated the development of syntactic awareness in Cantonese-speaking children. Fifty-six subjects from four age groups (three, five, seven and 20 years old) were asked to judge the grammaticality of 40 sentences (18 with word-order changes and 22 with morphological violations) and correct the grammatically deviant sentences. There was a significant age effect on subjects' performance in both judgement and revision tasks. Children scored significantly higher in judging sentences with word order changes than those with morphological violations. They also scored higher on word order revisions than morphological revisions, an unexpected finding. The success of correcting morphological violations varied by morphological marker, apparently according to each marker's degree of obligatory use in the language. It would seem then that syntactic awareness is very much affected by language-specific characteristics.

Youth health promotion and health promoting schools: what should be the aims?

The school plays a very important role in health education and promotion at the crucial stage of childhood and adolescence. It develops personal character, skills, attitude and physique, in addition to imparting knowledge. To sustain the concerted effort to address inter-wined social, educational, psychological and health needs of children, training and ongoing reinforcement must be given to teachers. A task force made up of parents, teachers, administrators, students and health professionals must be formed to develop core values, visions, goals and activities; and to provide new direction for health education and promotion. The 'Health Promoting Schools' Programme of the CUHK was launched in 1999 with the aim to promote physical, emotional and intellectual development of students through healthy and hygienic practices. The programme has also conducted researches on health of students, prioritise and evaluate relevant programmes. Recent research studies revealed that students in higher grades had more physical and psychological health problems, probably due to heavy workload and less emphasis on health education in their formal curriculum. Another research study has shown the lack of concrete school policies in health education. It is therefore important to develop policies, practices and structures, as well as regular curricular reviews to promote health of the school children. The "Health Promoting Schools' Programme has already initiated several district based health promotion programmes to pave the way for the formation of local task force on youth health promotion.

Factors associated with osteoarthritis of the hip and knee in Hong Kong Chinese: obesity, joint injury, and occupational activities

In 1998, a case-control study was conducted in Hong Kong on hospital patients with osteoarthritis of the hip (n = 138) and osteoarthritis of the knee (n = 658). Age- and sex-matched controls were recruited consecutively from general practice clinics in the same region. The following three risk factors were found to be associated with osteoarthritis of both the hip and the knee: first, a history of joint injury: for osteoarthritis of the hip, the odds ratio = 25.1 (95% confidence interval (CI): 3.5, 181) in men and 43.3 (95% CI: 11.7, 161) in women; for osteoarthritis of the knee, the odds ratio = 12.1 (95% CI: 3.4, 42.5) in men and 7.6 (95% CI: 3.8, 15.2) in women; second, climbing stairs frequently: for osteoarthritis of the hip, the odds ratio = 12.5 (95% CI: 1.5, 104.3) in men and 2.3 (95% CI: 0.6, 8.1) in women; for osteoarthritis of the knee, the odds ratio = 2.5 (95% CI: 1.0, 6.4) in men and 5.1 (95% CI: 2.5, 10.2) in women; third, lifting heavy weight frequently: for osteoarthritis of the hip, the odds ratio = 3.1 (95% CI: 0.7, 14.3) in men and 2.4 (95% CI: 1.1, 5.3) in women; for osteoarthritis of the knee, the odds ratio = 5.4 (95% CI: 2.4, 12.4) in men and 2.0 (95% CI: 1.2, 3.1) in women. In addition, subjects whose height and weight were in the highest quartile were at increased risk of osteoarthritis of the hip and knee, respectively (p < 0.05).

Hip fracture in Hong Kong over the last decade--a comparison with the UK

BACKGROUND

Hip fracture is a major public health problem in Asia and the UK. The objectives of this study were to describe the trends of hip fracture in Hong Kong over the last decade, and to compare the incidence in Hong Kong with that from the Wessex Health Region of the UK in 1995.

METHODS

The number of hip fractures was calculated using hospital discharge records for all public hospitals in Hong Kong in 1991 and 1995. Age-specific incidence rates were then calculated using the mid-year census population for the two years. These rates were presented with previously reported age-specific rates for Hong Kong in 1966 and 1985. These age-specific rates for Hong Kong in 1995 were compared with rates for the Wessex Health Region of the UK. The total number of hip fracture expected in 2010 was calculated by applying the age-specific rates of 1995 to the projected population for 2010.

RESULTS

In 1995, a total of 1138 men and 2782 women in Hong Kong fractured their hip. The age-specific rates had remained static from 1985 to 1995, after substantial rise from 1966 to 1985. In 1995, the rates of hip fracture rates were 11/1000 in women and 5/1000 in men who were 70 years and older. These rates were almost identical to those observed in the Wessex Health Region of the UK.

CONCLUSION

The age-specific incidence rates of hip fracture had not risen in Hong Kong in the last decade. The incidence of hip fracture in Hong Kong was similar to that in the UK in 1995. The total number of patients with hip fracture in Hong Kong will increase substantially in the future, as a result of the ageing of the population.

Prostatism and the burden of benign prostatic hyperplasia on elderly men

All men aged 40-79 years registered with two group general practices in Central Scotland were enumerated. Four hundred and ten men (249 in the working age group 40-64 years and 161 in retirement ages 65-79 years satisfied predetermined criteria for clinical benign prostatic hyperplasia (BPH) of prostatic weight > 20 g in the presence of urinary dysfunction and without evidence of malignancy. Despite a higher prevalence of BPH among the retirement group (428/1000) compared with men of working ages (202/1000), there were virtually no statistically significant differences between the two groups in terms of annoyance and interference in daily living activities caused by urinary dysfunction, frequency of urinary symptoms, or medical consultations for BPH. Although elderly men with BPH changed their lifestyle as a result of urinary dysfunction, only a low proportion of them disclosed their difficulties to a doctor. Increased education of the public and health care professionals about the nature and magnitude of the problem of BPH in elderly men is required.

A mass hepatitis B vaccination programme in Taiwan: its preparation, results and reasons for uncompleted vaccinations

Chronic hepatitis B infection is hyperendemic in Taiwan. A massive hepatitis B vaccination programme has been implemented since 1984. Eight years after its introduction, the HBsAg carrier rate in young children has decreased fivefold, and the protective efficacy of the vaccines is estimated to be 85%. Despite the successful execution of the programme, a certain percentage of the population declined vaccination. The reasons for not completing or for delaying the vaccination schedule are discussed. In conclusion, a flexible and target-specific campaign should be undertaken in the future.

Impact of benign prostatic hyperplasia on general well-being of men

Little is known about the impact of benign prostatic hyperplasia (BPH) on the general well-being of men with this condition. All men aged 40-79 years registered with a group general practice were enumerated. BPH was defined as enlargement of the prostate gland of equivalent weight > 20 g in the presence of symptoms of urinary dysfunction and/or a urinary peak flow rate < 15 ml/s, without evidence of malignancy. Four hundred and ten men (20% of those who participated) satisfied these criteria. The proportion of men with a negative feeling of well-being was higher in men with BPH than in men who did not have BPH. The difference was consistent for all aspects of well-being (anxiety, depression, self-control, vitality, being worried or being bothered by illness). Men with BPH had a higher level of bothersomeness attributed to urinary symptoms, and more interference in selected daily living activities caused by urinary dysfunction. These were related to worry or concern over urinary function and prostate cancer, together with a higher level of embarrassment caused by urinary dysfunction, compared with men who did not have BPH. Patients' feelings of well-being should be taken into account in the clinical management of BPH.

[Leukopenia and hypoxemia induced by hemodialysis]

Patients with uremia usually develop hypoxemia during hemodialysis therapy. It has been thought by most of the investigators that the development of hypoxemia is related to the impropriety of biocompatibility of the dialyzer membranes. Besides, acetate dialysate through metabolism may cause a decrease of respiratory quotient and some amount of CO2 may be lost during hemodialysis. The decrease of CO2 in the blood may induce hypoventilation and therefore develop hypoxemia. A total of 32 patients who received hemodialysis therapy were studied. They were divided into group A and group B. In group A, there were 14 males and 8 females. They were hemodialyzed with cuprophan dialyzer membrane for 22 times totally. In group B, there were 6 males and 4 females. They were hemodialyzed with PMMA dialyzer membrane for 16 times totally. In both groups, acetate dialysate was used. Arterial blood gas analyses were hemodialyzed with PMMA dialyzer membrane for 16 times totally. In both groups, acetate dialysate was used. Arterial blood gas analyses were performed before hemodialysis as the baseline and at 15, 30, 45, 60, 120, 180, 240, and 300 minutes during hemodialysis. White blood cell counts (WBC) were done at the same time when arterial blood gas analyses were performed. The results showed that in group A, a marked decrease of WBC at 15 minutes (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)