Failure of sterilization in a dental outpatient facility: Investigation, risk assessment, and management

In 2017, an incident of failed sterilization of dental instruments occurred at a large dental outpatient facility in Singapore. We aim to describe findings of the investigation of the sterilization breach incident, factors related to risk of viral transmission to the potentially affected patients, and the contact tracing process, patient management, and blood test results at a 6-month follow-up. A full assessment of the incident was immediately carried out. The factors related to risk of viral transmission due to affected instruments were analyzed using 3 keys points: breached step(s) and scale of the incident, prevalence of underlying bloodborne diseases and immunity in the Singapore population, health status of potential source patients, and type of dental procedure performed, and health status of affected patients and type of dental procedure received. Up to 72 affected instrument sets were used in 714 potentially affected patients who underwent noninvasive dental procedures. The investigation revealed that there was a lapse in the final step of steam sterilization, resulting in the use of incompletely sterilized items. The assessment determined that there was an extremely low risk of bloodborne virus transmission of diseases to the patients. At the 6-month follow-up, there were no infected/colonized cases found related to the incident. Lapses in the sterilization process for medical and dental instruments can happen, but a risk assessment approach is useful to manage similar incidents. Quick response and proper documentation of the sterilization process can prevent similar incidents.

A general experimental system for the development of acoustic logging tools

Laboratory testing is a pre-requisite for the practical application of new methods and techniques, and it is crucial in the research and development of acoustic well-logging tools. Various tools have been developed based on different acoustic logging theories and methods. Thus, these tools are equipped with different acoustic sonde structures. To meet the test requirements of different tools in a laboratory environment, we designed a general experimental system that includes hardware platform, software platform, and model wells according to the common structure of actual logging tools. Similar to the internal electrical structure of downhole tools, the hardware platform consists of several main parts, such as power supply, control and telemetering, acoustic emission, and data acquisition. The functions of this hardware platform include controlling the working sequence of the experiment, exciting the transmitter sonde, and collecting the acoustic signals received by the receiver sonde. The software platform installed in the host computer provides a human-computer interface for the experimental system to complete the data transmission between the host computer and the hardware platform, store measured data, and process the data in real time. The model wells approximate the actual engineering environment and stratum condition for system testing. A series of practical laboratory experiments is conducted in the model wells by using this experimental system. The process proves that the hardware and software of the experimental system can work in coordination, and the experimental system meets the basic testing requirements of conventional acoustic logging tools.

Epidemiology and clinical characteristics of invasive mould infections: A multicenter, retrospective analysis in five Asian countries

Formal, large-scale, multicenter studies of invasive mould infection (IMI) in Asia are rare. This 1-year, retrospective study was designed to assess the incidence and clinical determinants of IMI in centers in five countries (Thailand, Taiwan, Singapore, China, India). Patients treated in a single year (2012) were identified through discharge diagnoses, microbiology, and histopathology logs, and entered based on published definitions of IMI. A total of 155 cases were included (median age 54 years; 47.7% male). Of these, 47.7% had proven disease; the remainder had probable IMI. The most frequent host factors were prolonged steroid use (39.4%) and recent neutropenia (38.7%). Common underlying conditions included diabetes mellitus (DM; 30.9%), acute myeloid leukemia (19.4%), and rheumatologic conditions (11.6%). DM was more common in patients with no recent history of neutropenia or prolonged steroid use (P = .006). The lung was the most frequently involved site (78.7%), demonstrating a range of features on computed tomography (CT). Aspergillus was the most common mould cultured (71.6%), primarily A. fumigatus and A. flavus, although proportions varied in different centers. The most often used antifungal for empiric therapy was conventional amphotericin. Ninety-day mortality was 32.9%. This is the first multicenter Asian study of IMI not limited to specific patient groups or diagnostic methods. It suggests that DM and rheumatologic conditions be considered as risk factors for IMI and demonstrates that IMI should not be ruled out in patients whose chest features on CT do not fit the conventional criteria.

Donor-Derived Candida dubliniensis Resulting in Perigraft Abscesses in a Liver Transplant Recipient Proven by Whole Genome Sequencing: A Case Report

BACKGROUND

The transmission of fungi via transplant, although well-known, has not often been molecularly proven. We describe a case of donor-derived candidiasis verified by whole genome sequencing.

CASE DESCRIPTION

The multiorgan donor was a 42-year-old woman with subdural hemorrhage. Procurement of the thoracic organs was performed followed by the abdominal organs. Tissue from the left bronchus grew Candida dubliniensis. The liver recipient was a 63-year-old woman with cryptogenic liver cirrhosis. She was noted to have worsening leukocytosis on postoperative day (POD) 9. Computed tomography of the abdomen and pelvis showed multiple rim-enhancing collections around the graft. Percutaneous drainage was performed. Fluid cultures grew C dubliniensis. C dubliniensis isolated from the donor's left bronchus and the liver recipient's abscesses were verified to be related by whole genome sequencing. We postulate that C dubliniensis colonizing the donor's transected trachea could have contaminated the inferior vena cava when the former was left open after explant of the donor's lungs. A portion of the donor's contaminated inferior vena cava was transplanted along with the liver graft, resulting in the infected collections in the recipient.

CONCLUSIONS

Our case report highlights the importance of maintaining a sterile field during organ procurement, especially in a multiorgan donor whose organs are explanted in succession.

Recurrent trichosporonosis with central nervous system involvement in an allogeneic hematopoietic stem cell transplant recipient

Trichosporon is an ubiquitous yeast that has emerged as an opportunistic pathogen in the immunocompromised host. We describe a case of invasive trichosporonosis in an allogeneic hematopoietic stem cell transplant (allo-HSCT) recipient while on caspofungin antifungal prophylaxis. She developed disseminated trichosporonosis in the pre-engraftment period and was successfully treated with voriconazole. She later developed 2 further episodes of invasive trichosporonosis involving the central nervous system. This case highlights the challenges of managing trichosporonosis in allo-HSCT recipients and suggests the need for lifelong therapy in some patients.

Deep branch of the radial nerve in lateral surgical approaches to the radial head - A cadaveric study

INTRODUCTION

The traditional Kocher approach for lateral radial head exposure may be complicated by injury to the deep branch of the radial nerve (DBRN) and the radial collateral ligament. Kaplan approach is less commonly used, due to its known proximity to the DBRN. Extensor Digitorum Communis (EDC) splitting approach allows possible wide surgical exposure and low risk of radial collateral ligament injury. The comparison of the proximity of the DBRN to the surgical dissection at the level of radial head among approaches to the radial head has not previously been evaluated. We aimed to determine the anatomical proximity of the DBRN in these 3 common radial head approaches and to define a safe zone of dissection for the surgical exposure.

METHODS

Cadaveric dissections of 9 pairs of fresh frozen upper extremities were performed using EDC splitting, Kaplan and Kocher approach to the radial head sequentially in a randomized order. A mark was made on the radial head upon initial exposure during dissection. Measurements from the marked point of the radial head to the DBRN were made at the level of radial head.

RESULTS

The distance of DBRN to the radial head was 20 (17-22) mm in EDC splitting approach, 7 (3-11) mm in Kaplan approach and 29 (25-33) mm in Kocher approach. The EDC splitting approach was associated with a significantly lower chance of encountering the DBRN at the level of radial head as compared to the Kaplan approach (P<0.001). In all cases, lateral ligamentous complex was not exposed in Kaplan and EDC approaches, but were encountered in Kocher approach, risking injury to the radial collateral ligament.

CONCLUSIONS

The EDC splitting approach provides adequate exposure without the need to elevate or retract the EDC and ECU muscle mass that could risk injuring the DBRN. The Kaplan approach should be done by experienced surgeons who are familiar with the anatomy in this region, with extreme caution due to proximity of the DBRN to the surgical dissection at the level of the radial head. Caution of the DBRN should be taken during anterior elevation and retraction of the muscle mass in Kocher approach.

LEVEL OF EVIDENCE

IV.

Genetic basis of interindividual susceptibility to cancer cachexia: selection of potential candidate gene polymorphisms for association studies

Cancer cachexia is a complex and multifactorial disease. Evolving definitions highlight the fact that a diverse range of biological processes contribute to cancer cachexia. Part of the variation in who will and who will not develop cancer cachexia may be genetically determined. As new definitions, classifications and biological targets continue to evolve, there is a need for reappraisal of the literature for future candidate association studies. This review summarizes genes identified or implicated as well as putative candidate genes contributing to cachexia, identified through diverse technology platforms and model systems to further guide association studies. A systematic search covering 1986-2012 was performed for potential candidate genes / genetic polymorphisms relating to cancer cachexia. All candidate genes were reviewed for functional polymorphisms or clinically significant polymorphisms associated with cachexia using the OMIM and GeneRIF databases. Pathway analysis software was used to reveal possible network associations between genes. Functionality of SNPs/genes was explored based on published literature, algorithms for detecting putative deleterious SNPs and interrogating the database for expression of quantitative trait loci (eQTLs). A total of 154 genes associated with cancer cachexia were identified and explored for functional polymorphisms. Of these 154 genes, 119 had a combined total of 281 polymorphisms with functional and/or clinical significance in terms of cachexia associated with them. Of these, 80 polymorphisms (in 51 genes) were replicated in more than one study with 24 polymorphisms found to influence two or more hallmarks of cachexia (i.e., inflammation, loss of fat mass and/or lean mass and reduced survival). Selection of candidate genes and polymorphisms is a key element of multigene study design. The present study provides a contemporary basis to select genes and/or polymorphisms for further association studies in cancer cachexia, and to develop their potential as susceptibility biomarkers of cachexia.

Incidence and species distribution of candidaemia in Asia: a laboratory-based surveillance study

The epidemiology of candidaemia varies between hospitals and geographic regions. Although there are many studies from Asia, a large-scale cross-sectional study across Asia has not been performed. We conducted a 12-month, laboratory-based surveillance of candidaemia at 25 hospitals from China, Hong Kong, India, Singapore, Taiwan and Thailand. The incidence and species distribution of candidaemia were determined. There were 1601 episodes of candidaemia among 1.2 million discharges. The overall incidence was 1.22 episodes per 1000 discharges and varied among the hospitals (range 0.16-4.53 per 1000 discharges) and countries (range 0.25-2.93 per 1000 discharges). The number of Candida blood isolates and the total number of fungal isolates were highly correlated among the six countries (R² = 0.87) and 25 hospitals (R² = 0.77). There was a moderate correlation between incidence of candidaemia and the intensive care unit (ICU)/total bed ratio (R² = 0.47), although ICUs contributed to only 23% of candidaemia cases. Of 1910 blood isolates evaluated, Candida albicans was most frequently isolated (41.3%), followed by Candida tropicalis (25.4%), Candida glabrata (13.9%) and Candida parapsilosis (12.1%). The proportion of C. tropicalis among blood isolates was higher in haemato-oncology wards than others wards (33.7% versus 24.5%, p 0.0058) and was more likely to be isolated from tropical countries than other Asian countries (46.2% versus 18.9%, p 0.04). In conclusion, the ICU settings contribute, at least in part, to the incidence variation among hospitals. The species distribution is different from Western countries. Both geographic and healthcare factors contribute to the variation of species distribution.

Bilateral adrenal histoplasmosis: endoscopic ultrasound-guided fine needle aspiration as a method of diagnosis and assessment

We report a case of a healthy 78-year-old indonesian man who presented with chronic weight loss, poor appetite and lethargy. CT abdomen showed bilateral adrenal masses. EUS-guided FNA was performed on the left adrenal gland. Histopathology report was Histoplasma Capsulatum. He recovered well with antifungal treatment without any complication. In this case, we found that the role of EUS -guided FNA was not only limited to diagnosis but also helped in the prognosis of the disease since the method was able to assess the general anatomy of the adrenal gland better than other imaging modalities due to its close proximity and direct visualization.

Disseminated Mycobacterium marinum infection in a hematopoietic stem cell transplant recipient

Mycobacterium marinum is a photochromogenic mycobacterium that is ubiquitous in the aquatic environment. In the general population, exposure to aquaria is the most common cause of M. marinum infection. Known as "swimmer's granuloma" or "fish tank granuloma," M. marinum is an occupational hazard for aquarium cleaners and fishermen. There are several reports in the literature of M. marinum infection in immunocompromised hosts, including those with solid organ transplants, but none in patients who have received stem cell transplants (SCTs). To our knowledge, this is a first report of disseminated M. marinum infection in an SCT recipient who continued to develop new skin lesions even after months of targeted therapy. The implications are that elderly patients who receive T-cell-depleted SCTs may be at prolonged risk for pathogens dependent on cellular immunity, and the presentation of illness with such pathogens may be more severe and widely disseminated than might otherwise be expected.

Stable dispersions of hybrid nanoparticles induced by stereocomplexation between enantiomeric poly(lactide) star polymers

We report the formation and characterization of stable dispersions of hybrid nanoparticles in solution formed via stereocomplexation of enantiomeric poly(lactide) hybrid star polymers. The hybrid starlike polymers, having polyhedral oligomeric silsesquioxane (POSS) nanocages as the core and either poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) as the arms, are synthesized via ring-opening polymerization of lactide using octafunctional POSS as the macroinitiator. In the solid state, differential scanning calorimetry and wide-angle X-ray scattering measurements confirmed the formation of the stereocomplex in the mixture of POSS-star-PLLA and POSS-star-PDLA (50:50, wt %). In a solution of the same mixture in tetrahydrofuran (THF), sterocomplexation leads to formation of hybrid nanaoparticles. Detailed accounts of the nanoparticle formation and influence of aging and concentration have been presented. It was observed that at low concentration the stereocomplexed nanaoparticles remain stable over 45 days and are not sensitive to dilution, suggesting the formation of a stable hybrid nanoparticle dispersion in solution. In contrast, the aggregates of the individual POSS-star-PLLA or POSS-star-PDLA in THF, formed via weak solvophobic interactions, tended to disintegrate into smaller aggregates on dilution. Exploiting the PLLA-PDLA stereocomplexation with an appropriate molecular design can be a versatile route to develop stable organic/inorganic hybrid nanoparticle dispersions.

Intravenous zanamivir in critically ill patients due to pandemic 2009 (H1N1) influenza A virus

INTRODUCTION

The 2009 (H1N1) influenza A pandemic started in April 2009 and has since spread globally. We have noticed that critically ill patients with confirmed pandemic 2009 (H1N1) influenza A require mechanical ventilation. This paper describes the use of intravenous zanamivir in this group of patients.

METHODS

Patients who had severe pneumonia with 2009 (H1N1) influenza A and required intravenous zanamivir were referred to the Infectious Diseases Department of our institution. Clinical data was collected from these patients. Clinical samples were sent to the National Public Health Laboratory for sequencing.

RESULTS

A total of five patients used intravenous zanamivir from April 8 to May 8, 2010. Only one death was reported. There were no side effects attributable to the use of intravenous zanamivir. H275 mutation, which confers resistance to oseltamivir, was seen in a subpopulation of the virus in one case.

CONCLUSION

Physicians can consider using intravenous zanamivir for the treatment of critically ill patients with 2009 (H1N1) influenza A infection.

Micelle formation and gelation of (PEG-P(MA-POSS)) amphiphilic block copolymers via associative hydrophobic effects

A series of well-defined amphiphilic di- and triblock copolymers have been synthesized, using atom transfer radical polymerization, with poly(ethylene glycol) (PEG) and poly(methacrylisobutyl polyhedral oligomeric silsesquioxane) P(MA-POSS) as the hydrophilic and hydrophobic blocks, respectively. The detailed self-assembly behavior of the amphiphilic macromolecules in aqueous media was studied using both static and dynamic light scattering (SLS and DLS) techniques. The evolution of block copolymer micelle formation in THF/water mixture (20/80 v/v) was monitored as the THF evaporated from the solvent mixture. Initially the block copolymer chains existed as unimers in solution, followed by the formation of smaller aggregates (R(h) < 2 nm) after 30 min, eventually growing in size to reach an equilibrium size when all the THF evaporated within 24 h. The micelles formed by the block copolymers were found to be kinetically unstable (not frozen); i.e., they tended to revert to individual copolymer chains on dilution. The hydrodynamic radii, R(h), of the micelles varied with the degree of polymerization (DP) of the hydrophobic P(MA-POSS); for example, for PEG(5K)-b-P(MA-POSS), an increase from R(h) approximately 13.3 +/- 1.1 nm to R(h) approximately 17.5 +/- 1.4 nm was observed with a nominal change in the DP of P(MA-POSS) from 4 to 6. The micelles formed by the triblock copolymers (P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS)) were comparable in size to the diblock copolymer micelles; e.g., R(h) approximately 14.0 +/- 1.3 nm was found for P(MA-POSS)(4)-b-PEG(10K)-b-P(MA-POSS)(4). The micellar structures created by the triblocks in aqueous media were "flowerlike", where the PEG middle block adopted a loop conformation in the micelle corona. In addition to micelles, larger aggregates formed by P(MA-POSS)-b-PEG(10K)-b-P(MA-POSS) were also detected in solution. The larger aggregates may suggest a contribution from some PEG blocks adopting an extended conformation with one end dangling in solution, causing gelation at higher copolymer concentrations via intermicellar interactions. The P(MA-POSS)(4)-b-PEG(10K)-b- P(MA-POSS)(4) formed a gel in water at approximately 8.8 wt % copolymer concentration. No gel formation by diblock copolymers was observed; however, the addition of a small amount of triblock copolymer to an aqueous solution of diblock copolymer results in gel formation. Finally, rheological behavior of the obtained gels was also investigated.

Synthesis and self-assembly of brush-type poly[poly(ethylene glycol)methyl ether methacrylate]-block-poly(pentafluorostyrene) amphiphilic diblock copolymers in aqueous solution

Well-defined fluorinated brush-like amphiphilic diblock copolymers of poly[poly(ethylene glycol)methyl ether methacrylate] (P(PEGMA)) and poly(pentafluorostyrene) (PPFS) have been successfully synthesized via atom transfer radical polymerization (ATRP). The self-assembly behavior of these polymers in aqueous solutions was studied using (1)H NMR, fluorescence spectrometry, static and dynamic light scattering and transmission electron microscopy techniques. The micellar structure comprised of PPFS as the core and brush-like (hydrophobic main chain and hydrophilic branches) polymers as the coronas. The hydrodynamic radius (R(h)) of the micelles in aqueous solution was in the nanometer range, independent of the polymer concentration, consistent with a closed association model. Diblock copolymers with a longer P(PEGMA) block formed micelles with smaller R(h) and lower aggregation numbers consistent with an improved solubilization of the core. The micelles possessed a thick hydration layer as verified by the ratio of the radius of gyration, R(g) to the hydrodynamic radius, R(h). The aggregation number and ratio of R(g) to R(h) were observed to increase with temperature (20-50 degrees C), while the R(h) of the micelle decreased slightly over the same temperature range. An increase in temperature induced the brush-like PEG segments in the corona to dehydrate and shrink while forming micelles with larger aggregation numbers.

Using transcriptomics to identify and validate novel biomarkers of human skeletal muscle cancer cachexia

Background

Cancer cachexia is a multi-organ tissue wasting syndrome that contributes to morbidity and mortality in many cancer patients. Skeletal muscle loss represents an established key feature yet there is no molecular understanding of the disease process. In fact, the postulated molecular regulators of cancer cachexia originate largely from pre-clinical models and it is unclear how these translate to the clinical environment.

Methods

Rectus abdominis muscle biopsies were obtained from 65 upper gastrointestinal (UGI) cancer patients during open surgery and RNA profiling was performed on a subset of this cohort (n = 21) using the Affymetrix U133+2 platform. Quantitative analysis revealed a gene signature, which underwent technical validation and independent confirmation in a separate clinical cohort.

Results

Quantitative significance analysis of microarrays produced an 83-gene signature that was able to identify patients with greater than 5% weight loss, while this molecular profile was unrelated to markers of systemic inflammation. Selected genes correlating with weight loss were validated using quantitative real-time PCR and independently studied as general cachexia biomarkers in diaphragm and vastus lateralis from a second cohort (n = 13; UGI cancer patients). CaMKIIβ correlated positively with weight loss in all muscle groups and CaMKII protein levels were elevated in rectus abdominis. TIE1 was also positively associated with weight loss in both rectus abdominis and vastus lateralis muscle groups while other biomarkers demonstrated tissue-specific expression patterns. Candidates selected from the pre-clinical literature, including FOXO protein and ubiquitin E3 ligases, were not related to weight loss in this human clinical study. Furthermore, promoter analysis identified that the 83 weight loss-associated genes had fewer FOXO binding sites than expected by chance.

Conclusion

We were able to discover and validate new molecular biomarkers of human cancer cachexia. The exercise activated genes CaMKIIβ and TIE1 related positively to weight-loss across muscle groups, indicating that this cachexia signature is not simply due to patient inactivity. Indeed, excessive CaMKIIβ activation is a potential mechanism for reduced muscle protein synthesis. Our genomics analysis also supports the view that the available preclinical models do not accurately reflect the molecular characteristics of human muscle from cancer cachexia patients.

Micelle formation of amphiphilic polystyrene-b-poly(N-vinylpyrrolidone) diblock copolymer in methanol and water-methanol binary mixtures

The micelle formation by the amphiphilic polystyrene-block-poly(N-vinylpyrrolidone) (PS48-b-PNVP99) copolymer is investigated in methanol and water-methanol binary mixtures of various compositions using 1H NMR, fluorescence spectroscopy, static/dynamic light scattering (SLS/DLS), and transmission electron microscopy (TEM). Critical micelle concentrations (cmc) are determined by employing fluorescence spectroscopy and DLS measurements. The cmc of the PS48-b-PNVP99 block copolymer increases with increasing methanol content in the water-methanol binary mixtures, suggesting that methanol is a better solvent for the PS48-b-PNVP99 block copolymer than water-methanol mixtures or pure water. The amphiphilic PS48-b-PNVP99 diblock copolymer forms spherical micelles of Rh approximately 16 nm in pure methanol solution as revealed by DLS measurements. In contrast, significantly larger micelles having higher aggregation numbers are formed in water-methanol binary mixtures. Temperature dependent data reveal an increase in aggregation number and radius of gyration (Rg) concomitantly with temperature (10-40 degrees C). In contrast, the overall size (Rh) of the micelles remains almost constant over the same temperature range. An explanation is tendered that PNVP coronas dehydrate/desolvate at higher temperatures counteracting the increase in micelle size (Rh) caused by increased aggregation numbers (Nagg).

The influence of systemic inflammation, dietary intake and stage of disease on rate of weight loss in patients with gastro-oesophageal cancer

Although weight loss is often a dominant symptom in patients with upper gastrointestinal malignancy, there is a lack of objective evidence describing changes in nutritional status and potential associations between weight loss, food intake, markers of systemic inflammation and stage of disease in such patients. Two hundred and twenty patients diagnosed with gastric/oesophageal cancer were studied. Patients underwent nutritional assessment consisting of calculation of body mass index, measurement of weight loss, dysphagia scoring and estimation of dietary intake. Serum acute-phase protein concentrations were determined by enzyme-linked immunosorbent assay. In all, 182 (83%) patients had lost weight at diagnosis (median loss, 7% body weight). Weight loss was associated with poor performance status, advanced disease stage, dysphagia, reduced dietary intake and elevated serum C-reactive protein (CRP) concentrations. Multiple regression identified dietary intake (estimate of effect, 38%), serum CRP concentrations (estimate of effect, 34%) and stage of disease (estimate of effect, 28%) as independent variables in determining degree of weight loss. Mechanisms other than reduced dietary intake or mechanical obstruction by the tumour appear to be involved in the nutritional decline in patients with gastro-oesophageal malignancy. Recognition that systemic inflammation plays a role in nutritional depletion may inform the development of appropriate therapeutic strategies to ameliorate weight loss, making patients more tolerant of cancer-modifying treatments such as chemotherapy.

Management of pyogenic liver abscesses - percutaneous or open drainage?

This pictorial essay aims to review the literature on the management of pyogenic liver abscess, focusing on the choice of drainage. Articles on the treatment of pyogenic liver abscess, accessed through a MEDLINE search using PubMed, were reviewed. A case series of the authors' experience with clinicopathological correlation is presented to highlight the indication and outcome of each modality of drainage. Intravenous antibiotic is the first line, and mainstay, of treatment. Drainage is necessary for large abscesses, equal to or larger than 5 cm in size, to facilitate resolution. While percutaneous drainage is appropriate as first-line surgical treatment in most cases, open surgical drainage is prudent in cases of rupture, multiloculation, associated biliary or intra-abdominal pathology. Percutaneous drainage may help to optimise clinical condition prior to surgery. Laparoscopic drainage is a feasible surgical option with promising results in the future. Liver resection is reserved for concomitant localised intrahepatic disease and tumour, after control of sepsis. The final verdict on the outcome of percutaneous versus open surgical drainage of pyogenic liver abscesses requires further studies in a controlled trial setting. Nevertheless, in current good clinical practices, the choice of therapy needs to be individualised according to patient's clinical status and abscess factors. They are complementary in the management of liver abscesses.

Fluoroquinolones may delay the diagnosis of tuberculosis

INTRODUCTION

Fluoroquinolones (FQs), frequently used for many common infections such as community-acquired pneumonia and urinary tract infection, are also effective against Mycobacterium tuberculosis. This study describes a series of patients in whom the empirical use of FQs for what appeared to be common community-acquired infections led to a delay in the diagnosis of tuberculosis (TB).

METHODS

We reviewed the records of five patients with TB in whom the early use of FQs led to partial symptom resolution and a prolonged relapsing and remitting course.

RESULTS

Of the five patients described, four presented with community-acquired pneumonia and one with urinary tract infection. All were given FQs and improved, though not completely. Their illnesses took a relapsing and remitting course. TB was eventually diagnosed, in four of them by culture and in one by characteristic histopathology (this patient required surgical resection of a lung abscess).

CONCLUSION

FQs may lead to partial symptom resolution in TB. We highlight the problem of a delayed diagnosis, and voice our concern about inadvertent monotherapy of TB in such cases.

Emergence of community-associated methicillin-resistant Staphylococcus aureus in Singapore: a further six cases

INTRODUCTION

The clinical features and molecular epidemiology of further cases of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in Singapore are described.

METHODS

Six cases of CA-MRSA infection that occurred between April and October 2004 are described. The bacterial isolates were tested for the presence of Panton-Valentine leukocidin (PVL) genes and typed via pulsedfield gel electrophoresis, staphylococcal chromosomal cassette mec (SCCmec) and multi-locus sequence typing. The results were compared with that of previously-reported local and international CA-MRSA isolates.

RESULTS

There were four cases of cutaneous abscesses and one each of chronic osteomyelitis and endocarditis. CA-MRSA isolates from the last two cases tested negative for PVL genes. Three isolates were identical and related to the Oceanian clone, and one isolate to the predominant Taiwanese clone. The isolate causing osteomyelitis had a novel sequence type.

CONCLUSION

CA-MRSA, though uncommon, is being isolated with increasing frequency in Singapore. A predominant clone (ST30- MRSA-IV) seems to be emerging locally.

Oyster-associated outbreaks of Norovirus gastroenteritis in Singapore

Outbreaks of gastroenteritis associated with the consumption of raw imported half-shelled frozen oysters occurred in Singapore between 16 Dec 2003 and 04 Jan 2004. A total of 305 cases were reported with clinical symptoms of diarrhoea (94%), abdominal cramps (72%), vomiting (69%) and fever (54%). The median incubation period was 30.8h and the duration of illness was 2-3 days. The overall relative risk of oyster consumption was 14.1 (95% CI: 8.3-24.0, P<0.001). Stool and oyster samples tested negative for common bacterial pathogens, including Vibrio parahaemolyticus. However, stool samples were positive for the presence of Norovirus group II RNA via RT PCR while oyster samples indicated the presence of Norovirus particles by electron microscopy. The clinical and epidemiological features were suggestive of Norovirus gastroenteritis and were subsequently confirmed by laboratory tests of stools and implicated oysters. Steps have been taken to ensure that food outlets do not thaw frozen oysters and serve them raw.

Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore

BACKGROUND

Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths.

AIMS

To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use.

METHODS

A self-administered questionnaire survey of 14,554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May-July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis.

RESULTS

A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were "useful in protecting from contracting SARS". Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW's job title, reported contact with SARS patients, area of work, and Impact Events Scale scores.

CONCLUSION

A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.

Candida spondylodiscitis and epidural abscess: management with shorter courses of anti-fungal therapy in combination with surgical debridement

Epidural abscess associated with candidal spondylodiscitis is rarely seen, particularly when it involves the cervical and thoracic spine. We report two such cases that were successfully managed with early surgical debridement, as well as medical therapy with intravenous amphotericin followed by oral fluconazole. The literature related to candidal spinal infection is reviewed, and a rational approach to the management of this uncommon condition is proposed. A good outcome may generally be expected with early diagnosis as well as appropriate surgical and pharmacological treatment. Oral fluconazole appears to be useful in the management of candida spondylodiscitis complicated by epidural abscess formation. Treatment until a normal ESR is attained is ideal, and this may be as short as 3 months when surgical drainage has been adequately performed.

Cavitating cryptococcal pneumonia in the immunocompetent host

INTRODUCTION

Isolated cryptococcal pneumonia in the immunocompetent host is a rare infection. Indications for treatment and its duration are currently not defined.

CLINICAL PICTURE

Three patients presented with cavitating cryptococcal pneumonia.

TREATMENT

They were treated with oral fluconazole.

OUTCOME

Improvement was evident clinically, radiologically and serologically. Fluconazole was continued until serum cryptococcal antigen (SCA) levels were negative in our patients as they had manifestations such as haemoptysis, cavitating or multi-lobar pneumonia and relatively high antigen levels, suggesting potentially serious disease.

CONCLUSIONS

Fluconazole is effective and safe for the treatment of cryptococcal pneumonia in the immunocompetent host. Although the role of monitoring SCA levels in the immunocompetent host is currently unclear, it may be an indication of infective burden and the benefits of longer treatment seem to outweigh the risks.

Direct identification of Mycobacterium haemophilum in skin lesions of immunocompromised patients by PCR-restriction endonuclease analysis

PCR-restriction endonuclease analysis (PRA) was used for direct identification of Mycobacterium haemophilum in clinical specimens from immunocompromised patients. PRA correctly identified M. haemophilum in four smear-positive specimens. Direct identification by PRA takes 2 to 3 working days compared to the 3 to 5 weeks required for culture isolation and identification by conventional methods.

Bacteremia caused by Gordonia bronchialis in a patient with sequestrated lung

Gordonia species have been recognized as pathogens in immunocompromised and immunocompetent patients. We report the first case of bacteremia due to Gordonia bronchialis in a diabetic patient with a sequestrated lung. Species identification was confirmed with mycolic acid analysis by high-performance liquid chromatography and sequencing of the 16S rRNA gene.

Myocardial infarction in Singapore: a nationwide 10-year study of multiethnic differences in incidence and mortality

INTRODUCTION AND METHODS

Cardiovascular diseases have progressively increased in importance as a major contributor of morbidity and mortality in Asia. However, many countries in Asia do not have nationwide systematically-collected and standardised data on myocardial infarction (MI). To accurately document the extent of atherosclerotic coronary heart disease in Singapore, a nationwide myocardial infarct registry was established in the mid-1986. Possible myocardial infarct events were identified through daily national lists of cardiac enzymes, hospital discharge codes, mortuary records and the national death registry. Data obtained from clinical history, cardiac enzymes and 12-lead electrocardiogram Minnesota codes were entered into an algorithm based on the WHO MONICA study. Cases identified as "definite" MI were included in the decade's review for this study.

RESULTS

From 1988 to 1997, 13,048 myocardial infarct events were diagnosed with 3367 deaths. There was a 39.1% decline in mortality, with an average decline of 6.5% per year [95% confidence intervals (CI), -3.9% to -9.1%]. However, the decline in incidence was only 20.8% with an average decline of 2.4% per year (95% CI, -6.6% to -1.2%). The highest incidence and mortality rates for both genders were seen in the Indians, followed by the Malays and the Chinese.

CONCLUSION

Over 10 years, from 1988 to 1997, we documented a significant fall in mortality from MI in Singapore. There was a smaller decline in the incidence of infarction. Singapore implemented a National Healthy Lifestyle Programme in 1992 as a 10-year effort. The disparity in the incidence and mortality may suggest that a more dramatic and immediate impact has taken place in mortality through therapeutic programmes; primary preventive programmes would be more difficult to evaluate and have a more gradual impact. Only with continual accurate data collection through the whole country, over a much longer period, can the relative value of preventive and therapeutic programmes in coronary heart disease be assessed.

Outcome of percutaneous nephrostomy for the management of pyonephrosis

OBJECTIVE

The aim of this study was to evaluate the efficacy of percutaneous nephrostomy (PCN) drainage for the interim management of pyonephrosis.

METHODS

Ninety-two consecutive patients [29 men, 63 women; mean age, 57 years; range, 23 to 88] who underwent PCN for the treatment of pyonephrosis from 1996 to 1999 were evaluated retrospectively. The clinical presentation, bacteriology and patient outcomes were analyzed.

RESULTS

The majority [77%] of patients had underlying obstructing urinary calculi. Other causes of obstruction included strictures [9%], papillary necrosis [7%], pelvi-ureteric junction obstruction [4%] and malignant stricture [3%]. The microorganisms cultured were Escherichia coli [30%], Klebsiella [19%], Proteus [8%], Pseudomonas [5%], Enterococcus [5%], and Candida spp [5%]. The microorganisms were sensitive to gentamicin [79%], ceftriaxone [71%], cephalexin [54%], nitrofurantoin [40%], cotrimoxazole [35%], nalidixic acid [32%] and ampicillin [29%]. Only 30% of bladder urine cultures were positive for microorganisms; the addition of PCN cultures improved this yield to 58%. The antibiotic regimen was revised according to the PCN culture whenever there was a discrepancy. After PCN, 69% of patients underwent minimally invasive procedures as definitive treatment of the obstructing lesion. Only 14% of patients required open surgery. There was low procedure-related morbidity [14%] and low overall mortality [2%].

CONCLUSIONS

PCN cultures yield important bacteriological information. The procedure is associated with minimal morbidity, facilitates definitive treatment and provides therapeutic benefit.

Birth prevalence of Down syndrome in Singapore from 1993 to 1998

OBJECTIVE

To examine the livebirth prevalence rate of Down Syndrome in Singapore from 1993 to 1998.

DESIGN

Index cases for the National Birth Defects Register were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered.

SETTING

Information for the Register was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths.

SUBJECTS

All foetuses with Trisomy 21 diagnosed prenatally together with livebirths and stillbirths with Down Syndrome diagnosed at or after birth were identified from the Registry database.

MAIN OUTCOME MEASURES

Prevalence of Down Syndrome

RESULTS

From 1993 to 1998, there were 295 Down Syndrome livebirths, four stillbirths and 197 Down Syndrome foetuses aborted. There has been an increasing number of Down Syndrome foetuses diagnosed antenatally ending in termination and this is accompanied by a falling trend in the Down Syndrome livebirth rate in the same years from 1.17 to 0.89 per 1000 total live births. This is despite an expected increase in Down Syndrome livebirth rate obtained by modelling maternal Down Syndrome age-related risks on the maternal age distribution over the years.

CONCLUSIONS

The livebirth prevalence of Down Syndrome in Singapore has fallen over the years from 1.17/1000 livebirths in 1993 to 0.89/1000 livebirths in 1998 due to antenatal diagnosis and selective termination.

Silica sol-gel for the controlled release of antibiotics. I. Synthesis, characterization, and in vitro release

Room temperature processed silica sol-gel (xerogel) was investigated as a novel controlled release carrier of antibiotics (vancomycin). Xerogel characteristics, in vitro release properties, and bactericidal efficacy of the released antibiotic were determined. The xerogel/vancomycin composite showed a long-term sustained release (up to 6 weeks). In addition, bactericidal efficacy of released vancomycin was retained. The kinetics of release and the amount released were dose dependent. The initial, first-order release was followed by a near-zero-order release. The time to transition from the first- to zero-order release increased with vancomycin load (from 2 to 3 weeks with load increase from 2.2 to 11.1 mg/g). Regardless of the load, about 70% of the original vancomycin content was released by the transitional point, and the cumulative release after 6 weeks of immersion was about 90%. This study, combined with other reports documenting biocompatibility and controlled resorbability of the xerogel/drug composite in vivo, suggests that silica xerogel is a promising controlled release material for the treatment of bone infections.

Traumatic transection of aorta

A 16 year-old man presented with fracture of both his femurs after a road traffic accident. Chest radiograph revealed mediastinal widening. Subsequent CT scan and arch aortogram confirmed the findings of traumatic aortic arch transection at the isthmus. He underwent successful surgical repair. High index of suspicion and prompt actions are important in managing this potentially fatal but treatable condition.

Immunomodulating activity of mycobacterial heat shock protein 65 in tumor cells

In recent years, heat shock proteins have been shown to be effective in enhancing the immunogenicity of tumors. In this study, we examined the effect of mycobacterial hsp65 gene transfection in a non-immunogenic and aggressive tumor cell-line in order to understand the factors that could contribute to the increase in immunogenicity mediated by Hsp65. The transfected cells were found to have indeed lost their tumorigenenicity and increased their immunogenicity. Tumor-specific cytotoxic T cells were present only in mice immunized with the Hsp65-expressing cells. Furthermore, endogenous Hsp70 was significantly increased in irradiated Hsp65-expressing cells and recombinant Hsp65 protein was able to stimulate the mRNA expression of various T helper 1 (Th1) and pro-inflammatory cytokines in splenocyte cultures, as well as a modest expansion of CD4 T cells. These results provide further evidence of the immunomodulating properties of Hsp65, which could be exploited for the treatment of cancer.

Isolation and characterization of group II introns from Pseudomonas alcaligenes and Pseudomonas putida

Group II introns isolated from Pseudomonas alcaligenes NCIB 9867, Pseudomonas putida NCIB 9869, and P. putida KT2440 were closely related with nucleotide sequence identities of between 87 and 96%. The genome of P. alcaligenes also harbored a truncated group II intron of 682 bp that lacks the gene for the intron-encoded protein (IEP). Unlike most bacterial group II introns, the Pseudomonas introns were found to lack the Zn domains in their IEPs, did not appear to interrupt any genes, and were located downstream of open reading frames which were adjacent to hairpin loop structures that resemble rho-independent terminators. These structures also contain the intron binding sites 1 and 2 (IBS1 and IBS2 sequences) that were required for intron target site recognition in transposition. One of the group II introns found in P. alcaligenes, Xln3, was shown to have transposed from the chromosome to the endogenous pRA2 plasmid at a site adjacent to IBS1- and IBS2-like sequences.

RGD tripeptide of bluetongue virus VP7 protein is responsible for core attachment to Culicoides cells

Bluetongue virus (BTV) is an arthropod-borne virus transmitted by Culicoides species to vertebrate hosts. The double-capsid virion is infectious for Culicoides vector and mammalian cells, while the inner core is infectious for only Culicoides-derived cells. The recently determined crystal structure of the BTV core has revealed an accessible RGD motif between amino acids 168 to 170 of the outer core protein VP7, whose structure and position would be consistent with a role in cell entry. To delineate the biological role of the RGD sequence within VP7, we have introduced point mutations in the RGD tripeptide and generated three recombinant baculoviruses, each expressing a mutant derivative of VP7 (VP7-AGD, VP7-ADL, and VP7-AGQ). Each expressed mutant protein was purified, and the oligomeric nature and secondary structure of each was compared with those of the wild-type (wt) VP7 molecule. Each mutant VP7 protein was used to generate empty core-like particles (CLPs) and were shown to be biochemically and morphologically identical to those of wt CLPs. However, when mutant CLPs were used in an in vitro cell binding assay, each showed reduced binding to Culicoides cells compared to wt CLPs. Twelve monoclonal antibodies (MAbs) was generated using purified VP7 or CLPs as a source of antigen and were utilized for epitope mapping with available chimeric VP7 molecules and the RGD mutants. Several MAbs bound to the RGD motif on the core, as shown by immunogold labeling and cryoelectron microscopy. RGD-specific MAb H1.5, but not those directed to other regions of the core, inhibited the binding activity of CLPs to the Culicoides cell surface. Together, these data indicate that the RGD motif present on BTV VP7 is responsible for Culicoides cell binding activity.

Oral biopsy turnaround time: 20-year experience of the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya

The turnaround time (TAT) for oral biopsies received for histological examination by the Department of Oral Pathology, Oral Medicine and Periodontology, Faculty of Dentistry, University of Malaya, for the years 1978, 1988 and 1998 was evaluated. For the three years studied, TATs for 61, 233 and 463 specimens were retrospectively analysed. Testing intervals, that is, from the dates the surgeons procured the specimens, the laboratories accessioned them and until the pathologists signed off the diagnoses, were used to calculate TAT. The performance level of the respective pathologists, the growth of tissue diagnostic services and the possible variables that influence TAT were also evaluated. As prompt diagnosis means prompt treatment, which in turn has a bearing on prognosis, the TAT pertinent to oral malignant tumors was emphasized. The mean TAT, its mode and median fell significantly in 1998 compared with the previous 2 years; it was lower for soft tissue than for hard tissue specimens, and lower for malignant, than for non-malignant specimens. The progression of tissue diagnostic services is up to a satisfactory level, as 88.89 % of biopsies could render diagnoses within a fair period of time in 1998.

Comparison of quantitative cytomegalovirus (CMV) PCR in plasma and CMV antigenemia assay: clinical utility of the prototype AMPLICOR CMV MONITOR test in transplant recipients

The correlation between the prototype AMPLICOR CMV MONITOR test (Roche Molecular Systems), a quantitative PCR assay, and the cytomegalovirus (CMV) pp65 antigenemia assay was evaluated in transplant recipients. Sequential blood specimens were collected on 29 patients (491 specimens), the leukocyte fraction was tested by CMV antigenemia, and quantitative PCR was performed on plasma specimens. None of the 15 patients (242 specimens) who were antigenemia negative were positive for CMV DNA by PCR, and none of these patients developed active CMV disease. There were 14 antigenemia-positive patients, 8 of whom developed active CMV disease. In all patients, there was a good association between the antigenemia and PCR assays. Ganciclovir-resistant virus was isolated from three patients with active CMV disease. These three patients had persistently elevated levels of antigenemia and CMV DNA by PCR when resistance to ganciclovir developed. This standardized, quantitative CMV PCR assay on plasma has clinical utility for the diagnosis of active disease and in monitoring the response to antiviral therapy in transplant recipients.