Cardiac Substructure Dose and Survival in Stereotactic Radiotherapy for Lung Cancer: Results of the Multi-Centre SSBROC Trial.

BACKGROUND AND PURPOSE: Stereotactic ablative body radiotherapy (SABR) is increasingly used for early-stage lung cancer, however the impact of dose to the heart and cardiac substructures remains largely unknown. The study investigated doses received by cardiac substructures in SABR patients and impact on survival. MATERIALS AND METHODS: SSBROC is an Australian multi-centre phase II prospective study of SABR for stage I non-small cell lung cancer. Patients were treated between 2013 and 2019 across 9 centres. In this secondary analysis of the dataset, a previously published and locally developed open-source hybrid deep learning cardiac substructure automatic segmentation tool was deployed on the planning CTs of 117 trial patients. Physical doses to 18 cardiac structures and EQD2 converted doses (α/ß = 3) were calculated. Endpoints evaluated include pericardial effusion and overall survival. Associations between cardiac doses and survival were analysed with the Kaplan-Meier method and Cox proportional hazards models. RESULTS: Cardiac structures that received the highest physical mean doses were superior vena cava (22.5 Gy) and sinoatrial node (18.3 Gy). The highest physical maximum dose was received by the heart (51.7 Gy) and right atrium (45.3 Gy). Three patients developed grade 2, and one grade 3 pericardial effusion. The cohort receiving higher than median mean heart dose (MHD) had poorer survival compared to those who received below median MHD (p = 0.00004). On multivariable Cox analysis, male gender and maximum dose to ascending aorta were significant for worse survival. CONCLUSIONS: Patients treated with lung SABR may receive high doses to cardiac substructures. Dichotomising the patients according to median mean heart dose showed a clear difference in survival. On multivariable analyses gender and dose to ascending aorta were significant for survival, however cardiac substructure dosimetry and outcomes should be further explored in larger studies.

Dosimetric Impact of Delineation and Motion Uncertainties on the Heart and Substructures in Lung Cancer Radiotherapy.

AIMS: Delineation variations and organ motion produce difficult-to-quantify uncertainties in planned radiation doses to targets and organs at risk. Similar to manual contouring, most automatic segmentation tools generate single delineations per structure; however, this does not indicate the range of clinically acceptable delineations. This study develops a method to generate a range of automatic cardiac structure segmentations, incorporating motion and delineation uncertainty, and evaluates the dosimetric impact in lung cancer. MATERIALS AND METHODS: Eighteen cardiac structures were delineated using a locally developed auto-segmentation tool. It was applied to lung cancer planning CTs for 27 curative (planned dose ≥50 Gy) cases, and delineation variations were estimated by using ten mapping-atlases to provide separate substructure segmentations. Motion-related cardiac segmentation variations were estimated by auto-contouring structures on ten respiratory phases for 9/27 cases that had 4D-planning CTs. Dose volume histograms (DVHs) incorporating these variations were generated for comparison. RESULTS: Variations in mean doses (Dmean), defined as the range in values across ten feasible auto-segmentations, were calculated for each cardiac substructure. Over the study cohort the median variations for delineation uncertainty and motion were 2.20-11.09 Gy and 0.72-4.06 Gy, respectively. As relative values, variations in Dmean were between 18.7%-65.3% and 7.8%-32.5% for delineation uncertainty and motion, respectively. Doses vary depending on the individual planned dose distribution, not simply on segmentation differences, with larger dose variations to cardiac structures lying within areas of steep dose gradient. CONCLUSION: Radiotherapy dose uncertainties from delineation variations and respiratory-related heart motion were quantified using a cardiac substructure automatic segmentation tool. This predicts the 'dose range' where doses to structures are most likely to fall, rather than single DVH curves. This enables consideration of these uncertainties in cardiotoxicity research and for future plan optimisation. The tool was designed for cardiac structures, but similar methods are potentially applicable to other OARs.

Validation of a Fully Automated Hybrid Deep Learning Cardiac Substructure Segmentation Tool for Contouring and Dose Evaluation in Lung Cancer Radiotherapy.

BACKGROUND AND PURPOSE: Accurate and consistent delineation of cardiac substructures is challenging. The aim of this work was to validate a novel segmentation tool for automatic delineation of cardiac structures and subsequent dose evaluation, with potential application in clinical settings and large-scale radiation-related cardiotoxicity studies. MATERIALS AND METHODS: A recently developed hybrid method for automatic segmentation of 18 cardiac structures, combining deep learning, multi-atlas mapping and geometric segmentation of small challenging substructures, was independently validated on 30 lung cancer cases. These included anatomical and imaging variations, such as tumour abutting heart, lung collapse and metal artefacts. Automatic segmentations were compared with manual contours of the 18 structures using quantitative metrics, including Dice similarity coefficient (DSC), mean distance to agreement (MDA) and dose comparisons. RESULTS: A comparison of manual and automatic contours across all cases showed a median DSC of 0.75-0.93 and a median MDA of 2.09-3.34 mm for whole heart and chambers. The median MDA for great vessels, coronary arteries, cardiac valves, sinoatrial and atrioventricular conduction nodes was 3.01-8.54 mm. For the 27 cases treated with curative intent (planned target volume dose ≥50 Gy), the median dose difference was -1.12 to 0.57 Gy (absolute difference of 1.13-3.25%) for the mean dose to heart and chambers; and -2.25 to 4.45 Gy (absolute difference of 0.94-6.79%) for the mean dose to substructures. CONCLUSION: The novel hybrid automatic segmentation tool reported high accuracy and consistency over a validation set with challenging anatomical and imaging variations. This has promising applications in substructure dose calculations of large-scale datasets and for future studies on long-term cardiac toxicity.

Bioinformatics analysis of rhinovirus capsid proteins VP1-4 sequences for cross-serotype vaccine development.

BACKGROUND: Rhinoviruses (RV) are associated with the development and exacerbations of asthma and chronic obstructive pulmonary disease. They've also been linked to more severe diseases like pneumonia, acute bronchiolitis, croup, and otitis media. Because of the hypervariable sequences in the same serotypes, no effective vaccine against rhinoviruses has been developed to date. With the availability of new full-length genome sequences for all RV-A and RV-B serotyped strains, this study used bioinformatics to find a suitable RV strain with the highest similarity matrices to the other strains. METHODS: The full genomic sequences of all known different RV-A and -B prototypes were downloaded from the National Centre for Biotechnology Information (NCBI) and divided into minor low-density lipoprotein receptor (LDLR) and major intercellular adhesion molecule groups (ICAM). The sequences were edited using Biological Sequence Alignment Editor, v 7.2.0 (BioEdit software) to study each capsid protein (VP1, VP2, VP3, and VP4) and analyzed using the EMBL-EBI ClustalW server and the more current Clustal Omega tool for the calculation of the identities and similarities. RESULTS: We analyzed and predicted immunogenic motifs from capsid proteins that are conserved across distinct RV serotypes using a bioinformatics technique. The amino acid sequences of VP3 were found to be the most varied, while VP4 was the most conserved protein among all RV-A and RV-B strains. Among all strains studied, RV-74 demonstrated the highest degree of homology to other strains and could be a potential genetic source for recombinant protein production. Nine highly conserved regions with a minimum length of 9-mers were identified, which could serve as potential immune targets against rhinoviruses. CONCLUSION: Therefore, bioinformatics analysis conducted in the current study has paved the way for the selection of immunogenic targets. Bioinformatically, the ideal strain's capsid protein is suggested to contain the most common RVs immunogenic sites.

Inhibition of Activin A suppressed tumor necrosis factor-α secretion and improved histopathological conditions in malarial mice.

Malaria infection still remains as one of the most prominent parasitic diseases afflicting mankind in tropical and subtropical regions. The severity of malaria infection has often been associated to exuberant host immune inflammatory responses that could possibly lead to severe immunopathological conditions and subsequent death of host tissues. Activin A is a protein belonging to the transforming growth factor-beta (TGF-ß) family that regulates multiple physiological processes and pathological-associated diseases. The biological roles of activin A have been associated with manipulation of inflammation-related processes and modulation of host immune responses. This implies that activin A protein could play a role in malaria pathogenesis since malaria infection has been closely linked to severe immune responses leading to death, However, the actual in vivo role of activin A in malaria infection remains elusive. Hence, this study was undertaken to investigate the involvement of activin A in malaria infection as well as to assess the modulating effects of activin A on the cytokine releases (TNF-α, IFN-γ and IL-10) and histopathological changes in major affected organs (kidney, liver, lung, brain and spleen) in malarial mice infected with Plasmodium berghei ANKA. Our results showed that the concentrations of plasma activin A were significantly increased in malarial mice throughout the study periods. Also. the systemic activin A level was positively correlated with malaria parasitemia. This indicates that activin A could play a role in malaria pathogenesis and malaria parasitemia development. Plasma TNF-α, IFN-γ and IL-10 cytokine levels were significantly increased in malarial mice at day-5 post infection, suggesting that these cytokines attributed to severe malaria pathogenesis. Histopathological features such as sequestration of parasitized red blood cells (pRBCs) and hemozoin formation were amongst the most common pathological conditions observed in tissues of major affected organs (kidney, liver, lung, brain and spleen) in malarial mice. Neutralization of activin A production via recombinant mouse activin RIIA Fc chimera (rmActivin RIIA Fc chimera) had significantly reduced the parasitemia levels in malarial mice. The release of TNF-α cytokine was significantly reduced as well as the sequestration of parasitized pRBCs and hemozoin formation in major affected organs in malarial mice were also alleviated following inhibition of activin A production. Overall, this preliminary study suggests that activin A could play an immune modulation role in malaria pathogenesis through modulation of TNF-α release that benefits host from severe pathological destructions provoked by intensified inflammatory responses. Further studies are warranted to elucidate the precise mechanism of immune modulation mediated by activin A and its associated immune-modulation mediators in regulating the inflammatory responses elicited during the course of malaria infection.

Occupational exposure and challenges in tackling M. bovis at human-animal interface: a narrative review.

Zoonotic tuberculosis caused by Mycobacterium bovis (M. bovis), a member of Mycobacterium tuberculosis complex (MTBC) has increasingly gathered attention as a public health risk, particularly in developing countries with higher disease prevalence. M. bovis is capable of infecting multiple hosts encompassing a number of domestic animals, in particular cattle as well as a broad range of wildlife reservoirs. Humans are the incidental hosts of M. bovis whereby its transmission to humans is primarily through the consumption of cattle products such as unpasteurized milk or raw meat products that have been contaminated with M. bovis or the transmission could be due to close contact with infected cattle. Also, the transmission could occur through aerosol inhalation of infective droplets or infected body fluids or tissues in the presence of wound from infected animals. The zoonotic risk of M. bovis in humans exemplified by miscellaneous studies across different countries suggested the risk of occupational exposure towards M. bovis infection, especially those animal handlers that have close and unreserved contact with cattle and wildlife populations These animal handlers comprising of livestock farmers, abattoir workers, veterinarians and their assistants, hunters, wildlife workers as well as other animal handlers are at different risk of contracting M. bovis infection, depending on the nature of their jobs and how close is their interaction with infected animals. It is crucial to identify the underlying transmission risk factors and probable transmission pathways involved in the zoonotic transmission of M. bovis from animals to humans for better designation and development of specific preventive measures and guidelines that could reduce the risk of transmission and to protect these different occupational-related/populations at risk. Effective control and disease management of zoonotic tuberculosis caused by M. bovis in humans are also hindered by various challenges and factors involved at animal-human interface. A closer look into factors affecting proper disease control and management of M. bovis are therefore warranted. Hence, in this narrative review, we have gathered a number of different studies to highlight the risk of occupational exposure to M. bovis infection and addressed the limitations and challenges underlying this context. This review also shed lights on various components and approaches in tackling M. bovis infection at animal-human interface.

Progression of malaria induced pathogenicity during chloroquine therapy.

Treatment Failure with chloroquine is one of the challenges that faced the dedicated efforts to eradicate malaria This study aims at investigating the impact of treatment failure with chloroquine on the progression of the disease-induced histo-pathogenic and immunogenic outcomes. To achieve this, Rane's protocol with modifications was applied on a model of Plasmodium berghei ANKA infected ICR mice to determine the dose response curve of chloroquine and to screen the treatment impact on the disease progression. Chloroquine was given at 1, 5, 10, 15 and 20 mg/kg once the parasitemia reached to 20-30% (the experimental initiation point). During the subsequent days, the mice were monitored for changes in the clinical signs, hematology parameters and the progress of the parasitemia until the parasitemia reached to 60-70% (the experimental termination point) or up to 10 days after chloroquine administration in case of achieving a complete eradication of the parasite. At the end, the mice were exsanguinated and their blood and organs were collected for the biochemistry and the histology study. A complete eradication of the parasite was achieved at 20 mg/kg while recrudescence was observed at the lower doses. At 1 mg/kg, the parasite growth was comparable to that of the positive control. The histo-pathogenic and immunogenic changes were stronger in the groups that experienced recrudescence (at 5 and 10 mg/kg). All in all, the study highlights the possibility of having a worsened clinical condition when chloroquine is given at its sub-therapeutic doses during malaria treatment.

Massive hemorrhage protocol activation in obstetrics: a 5-year quality performance review.

BACKGROUND: A structured approach to hemorrhagic emergencies in obstetrics has gained popularity with the implementation of massive hemorrhage protocols. The trauma literature suggests that routine quality reviews should be in place to improve patient outcomes. The aim of this study was to develop quality indicators and assess compliance by the clinical team. METHODS: A multidisciplinary team set the institutional quality indicators for the massive hemorrhage protocol review. A retrospective review of all obstetrical massive hemorrhage protocol activation events from September 2010 to January 2015 was performed. All protocol events occurred before the creation of the quality indicators. Data were retrieved from patient records. RESULTS: There were 17 (0.09%) protocol activations for 19 790 deliveries during the study period. All 17 (100%) patients received at least one unit of red blood cells. Overactivation, defined as the transfusion of <2 units of red blood cells, occurred in two cases (12%). Common causes of non-compliance were: 24% (4/17) temperature monitoring, 18% (3/17) lactate measurement, 41% (7/17) arterial blood gas sampling, and 18% (3/17) hemoglobin maintenance within the target range of 55-95 g/L. Admission to intensive care and peripartum hysterectomy occurred in 12 and 5 cases (71% and 29%), respectively. CONCLUSIONS: Suboptimal compliance was found in multiple areas, which may be attributable to the low frequency of activation of our massive haemorrhage protocol in obstetrics. The quality targets identified in this report can act as a basis for other institutions developing quality indicators to evaluate performance.

Design and validation of small interfering RNA on respiratory syncytial virus M2-2 gene: A potential approach in RNA interference on viral replication.

Human respiratory syncytial virus (RSV) is the leading cause of severe lower respiratory tract infection in infants and young children globally and is a significant pathogen of the elderly and immunocompromised. The M2-2 protein of respiratory syncytial virus (RSV) is particularly important in regulation of viral RNA transcription and replication that could be a potential anti-viral candidate against RSV infection. In this study, we designed and validated siRNAs that specifically target the RSV M2-2 gene. Four siRNAs targeting different regions of the M2-2 gene were designed using web tool. In-vitro evaluation of silencing effect was performed by using RSV infected Vero cell line. Viral M2-2 linked GFP recombinant plasmid was co-transfected with non-targeted siRNA, Pooled siRNA, siRNA 1, siRNA 2, siRNA 3 and siRNA 4 using synthetic cationic polymer. The silencing effect of M2-2 gene at the protein level was measured both qualitatively and quantitatively by using fluorescence microscopy and flow cytometry. Meanwhile, the silencing effect at the mRNA level was assessed by using RT-qPCR. This study showed that all four designed siRNAs can effectively and efficiently silence M2-2 gene. siRNA 2 showed the highest (98%) silencing effect on protein level and siRNA 4 with 83.1% at the mRNA level. The viral assay showed no significant cytopathic effects observed after 6days post-infection with siRNAs. In conclusion, this study showed the effectiveness of siRNA in silencing M2-2 gene both at the protein and mRNA level which could potentially be used as a novel therapeutic agent in the treatment of RSV infection. However, further study is warranted to investigate the silencing effect of M2-2 protein and inhibition of RSV infection.

Adjuvant chemotherapy in elderly patients with pancreatic cancer.

BACKGROUND: Adjuvant chemotherapy improves survival for patients with resected pancreatic cancer. Elderly patients are under-represented in Phase III clinical trials, and as a consequence the efficacy of adjuvant therapy in older patients with pancreatic cancer is not clear. We aimed to assess the use and efficacy of adjuvant chemotherapy in older patients with pancreatic cancer. METHODS: We assessed a community cohort of 439 patients with a diagnosis of pancreatic ductal adenocarcinoma who underwent operative resection in centres associated with the Australian Pancreatic Cancer Genome Initiative. RESULTS: The median age of the cohort was 67 years. Overall only 47% of all patients received adjuvant therapy. Patients who received adjuvant chemotherapy were predominantly younger, had later stage disease, more lymph node involvement and more evidence of perineural invasion than the group that did not receive adjuvant treatment. Overall, adjuvant chemotherapy was associated with prolonged survival (median 22.1 vs 15.8 months; P<0.0001). Older patients (aged ≥70) were less likely to receive adjuvant chemotherapy (51.5% vs 29.8%; P<0.0001). Older patients had a particularly poor outcome when adjuvant therapy was not delivered (median survival=13.1 months; HR 1.89, 95% CI: 1.27-2.78, P=0.002). CONCLUSION: Patients aged ≥70 are less likely to receive adjuvant therapy although it is associated with improved outcome. Increased use of adjuvant therapy in older individuals is encouraged as they constitute a large proportion of patients with pancreatic cancer.

Candida albicans isolates from a Malaysian hospital exhibit more potent phospholipase and haemolysin activities than non-albicans Candida isolates.

This study was aimed at determining the phospholipase and haemolysin activity of Candida isolates in Malaysia. A total of 37 Candida clinical isolates representing seven species, Candida albicans (12), Candida tropicalis (8), Candida glabrata (4), Candida parapsilosis (1), Candida krusei (4), Candida orthopsilosis (1) and Candida rugosa (7) were tested. In vitro phospholipase activity was determined by using egg yolk plate assay whereas in vitro haemolysin activity was tested by using blood plate assay on sheep blood Sabouraud's dextrose agar (SDA) enriched with glucose. Phospholipase activity was detected in 75% (9 out of 12) of the C. albicans isolates. Among the 25 non- C. albicans Candida isolates, phospholipase activity was detected in only 24% of these isolates. The phospholipase activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.002). Haemolysin activity was detected in 100% of the C. albicans, C. tropicalis, C. glabrata, C. krusei, C. parapsilosis, and C. orthopsilosis isolates while 75% of the C. krusei isolates and 12.3% of the C. rugosa isolates showed haemolysin activity. The haemolytic activity of C. albicans was significantly higher than that of the non- C. albicans Candida isolates (P=0.0001).The findings in this study indicate that C. albicans isolates in Malaysia may possess greater virulence potential than the non-albicans species.

The prognostic and predictive value of serum CA19.9 in pancreatic cancer.

BACKGROUND: Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 (CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used. METHODS: We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC. RESULTS: By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P=0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels>90 U/ml did not benefit from adjuvant chemotherapy (P=0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P=0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P=0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%. CONCLUSIONS: Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.

An assessment of three noncommercial DNA extraction methods from dried blood spots for beta-thalassaemia mutation identification.

INTRODUCTION: Dried blood spots (DBS) are currently the recommended sample collection method for newborn screening programmes in America. Early diagnosis of beta-thalassaemia screening is essential as it provides an added advantage especially in sickle cell disease. Beta-thalassaemia frequency is high in many poor countries, and the cost of using commercial DNA extraction kits can be prohibitive. Our study assessed three methods that use minimal reagents and materials to extract DNA from DBS for beta-thalassaemia identification. METHODS: The methods assessed in this study were Tris-EDTA (TE) buffer-based method by Bereczky et al. (American Journal of Tropical Medicine and Hygiene 72, 2005, 249), NaCL/NaOH/Sodium dodecyl sulphate (SDS) method by Huang et al. (Human Genetics 84, 1990, 129) and NaOH method by Zhou et al. (Analytical Biochemistry 354, 2006, 159). Extracted DNA was amplified for three common beta-thalassaemia mutations in Malaysia. RESULTS: Amplicons derived from TE buffer-based method were very faint and almost nonexistent while the NaCl/NaOH/SDS method did not produce any visible amplicons. The extraction using NaOH method produced visible bands that were comparable to the standard method using extraction kit. CONCLUSION: The NaOH method is a simple method that uses minimal equipment and reagents that make it labour- and cost-effective. This method could be adopted by poorer countries to extract DNA for beta-thalassaemia mutation characterization.

Dynamics of antibiotic usage in the Intensive Care Unit at the University Hospital of the West Indies / Dinámica del uso de Antibióticos en la Unidad de Cuidados Intensivos del Hospital Universitario de West Indies

OBJECTIVE: To determine antibiotic usage patterns in the Intensive Care Unit (ICU) at the University Hospital of the West Indies (UHWI). METHOD: A cross-sectional, analytical study of consecutive patients admitted to the ICU was conducted between July and December 2007. Exclusion criteria were HIV-positive patients, patients < 12 years and those discharged or who died within 48 hours of admission. Data were collected from medical records, stored and analysed using the SPSS Version 12. RESULTS: Of the 150 eligible patients, 109 had complete data (73%). Mean age was 50.8 ± 20.7 years, with mean APACHE II score of 15.6 ± 6.7. Forty-five patients (41.3%) received prophylactic antibiotics, most commonly ceftriaxone (31.7%) and metronidazole (19.0%). Appropriate discontinuation within 24 hours occurred in only 11.1%. Two-thirds of patients (67.9%) were treated with empiric antibiotics, most commonly piperacillin/tazobactam (32.1%), ceftazidime (27.5%) or metronidazole (27.5%). Reasons for empiric choice were primarily coverage of organisms based on presumed source of sepsis (45.6%), and broad spectrum, high-powered coverage (23.5%). Courses ranged from 1 - 42 days and were adequate based on subsequent cultures in 71% of cases. Culture reports took between 2 - 8 days with a mean of 3.7 days to become available. De-escalation was practised in only 2 of 26 (7.7%) cases and intravenous to oral switch therapy in only 3.3%. Thirty-two (29.4%) patients died, with sepsis being a cause in 12 (37.5%). CONCLUSIONS: Improved attention to discontinuation of prophylactic antibiotics, appropriate duration of antibiotic courses and de-escalation are essential if the antibiotic practices in the ICU at the UHWI are to compare favourably with international recommendations.

OBJETIVO: Determinar los patrones de uso de antibióticos en la Unidad de Cuidados Intensivos (UCI) en el Hospital Universitario de West Indies. MÉTODO: Se llevó a cabo un estudio analítico transversal de un número de pacientes consecutivos ingresados a la UCI entre julio y diciembre de 2007. Los criterios de exclusión fueron los siguientes: pacientes positivos al VIH, pacientes < 12 años, y pacientes dados de alta o fallecidos dentro de las 48 horas de su ingreso. Los datos fueron tomados de las historias clínicas, y luego almacenados y analizados usando la versión doce de SPSS. RESULTADOS: De los 150 pacientes elegibles, 109 completaron los datos (73%). La edad promedio fue 50.8 ± 20.7 años, con una puntuación APACHE II media de 15.6 ± 6.7. Cuarenta y cinco pacientes (41.3%) recibieron antibióticos profilácticos, por lo general ceftriaxona (31.7%) y metronidazol (19.0%). Una descontinuación adecuada dentro de las 24 horas se produjo en sólo 11.1%. Dos tercios de los pacientes (67.9%) recibieron tratamiento antibiótico empírico, por lo general con piperacillinatazobactam (32.1%), ceftazidima (27.5%) o metronidazol (27.5%). Las razones para la opción empírica fueron principalmente la cobertura de organismos sobre la base de fuentes de sepsis presuntiva (45.6%), y el espectro ancho, cobertura de alta potencia (23.5%). Los cursos fluctuaron de 1 - 42 días y fueron adecuados a juzgar por los cultivos subsiguientes en 71% de los casos. Los reportes de cultivos tomaron entre 2 - 8 días con un promedio de 3.7 días para hallarse disponibles. El desescalamiento fue practicado en sólo 2 de 26 (7.7%) de los casos y cambio de terapia intravenosa a oral en sólo 3.3%. Treinta y dos (29.4%) pacientes murieron, siendo la sepsis la causa en 12 (37.5%). CONCLUSIONES: Una mayor atención en cuanto a descontinuar el uso de antibióticos profilácticos, una duración apropiada de cursos antibióticos, y el desescalamiento, son esenciales si se quiere que las prácticas antibióticas en las UCI en el HUWI puedan compararse favorablemente con las recomendaciones que se hacen a nivel internacional.

A survey of physicians' knowledge and attitudes regarding antimicrobial resistance and antibiotic prescribing practices at the University Hospital of the West Indies / Un estudio sobre los conocimientos y actitudes de los médicos en relación con la resistencia antimicrobiana y la práctica de prescripción de antibióticos en el Hospital Universitario de West Indies

OBJECTIVE: To identify physicians' knowledge and attitudes regarding antimicrobial resistance and antibiotic prescribing practices at the University Hospital of the West Indies (UHWI). METHODS: A cross-sectional survey of physicians at the UHWI was conducted between September 2008 and April 2009 using a 28-item, self-administered questionnaire. Eligible physicians from several specialities were identified from departmental rotas. RESULTS: A total of 174 physicians completed the questionnaire, a response rate of 73%. Most physicians considered antibiotic resistance to be an extremely important global problem (55%) but less significant nationally (35%). Factors identified as important in producing resistance included wide-spread use of antibiotics (91%), inappropriate empiric choices (79%) and use of broad-spectrum agents (70%). Hand-washing was not considered to be important in reducing resistance. Useful interventions included access to current information on local resistance patterns (90%), institutional specific antibiotic guidelines (89%) and educational programmes (89%). Antibiotic cycling (40%) and restriction (35%) were regarded as less helpful. Knowledge of resistance-prone antibiotics and specific resistant organisms at the UHWI was poor, except for methicillin-resistant Staphylococcus aureus (MRSA). Empiric therapy for common infections was appropriate in most cases, and antibiotic choices were guided by availability of drugs (89%) and patient factors such as renal disease or allergy (80%). Only 45% of physicians would de-escalate to a narrow-spectrum antibiotic guided by a microbiology report, and consultants were more likely to de-escalate therapy than junior staff (p = 0.002). CONCLUSIONS: Although physicians were aware of the problem of resistance to antibiotics and the contributory factors, their practice did not reflect measures to reduce it. Continuing educational programmes and institution-specific antibiotic prescribing guidelines are needed.

OBJETIVO: Identificar los conocimientos y actitudes de los médicos con respecto a la resistencia antimicrobiana y la práctica de prescripción de antibióticos en el Hospital Universitario de West Indies (UHWI). MÉTODOS: Se llevó a cabo un estudio transversal en UHWI, entre septiembre del 2008 y abril del 2009 de abril, usando un cuestionario autoadministrado de 28 puntos. Los médicos elegibles de varias especialidades fueron identificados de las listas departamentales. RESULTADOS: Un total de 174 médicos completaron el cuestionario, para una tasa de respuesta del 73%. La mayor parte de los médicos consideró que la resistencia antibiótica constituye un problema sumamente importante desde un punto de vista global (55%) pero menos significativo desde una perspectiva nacional (35%). Los factores identificados como importantes en la formación de la resistencia incluyeron el uso generalizado de antibióticos (91%), las elecciones empíricas inapropiadas (79%), y el uso de agentes de amplio espectro (70%). El lavarse las manos no se consideró importante para la reducción de la resistencia. Las intervenciones útiles incluyeron el acceso a la información corriente sobre patrones de resistencia locales (90%), normas institucionales específicas sobre el uso de antibióticos (89%) y programas educativos (89%). El ciclo (40%) y la restricción (35%) de los antibióticos se consideraron menos útiles. El conocimiento de antibióticos con tendencia a la resistencia y organismos resistentes específicos en el HUWI era pobre, excepto en el caso del Staphylococcus aureus resistente a la meticilina (SARM). La terapia empírica para las infecciones comunes fue apropiada en la mayoría de los casos, y las opciones antibióticas estuvieron dictadas por la disponibilidad de medicamentos (89%) y factores relacionados con los pacientes, tales como enfermedades renales o alergias (80%). Sólo el 45% de los médicos desescalarían a un antibiótico de estrecho espectro guiado por un informe microbiológico, y los consultantes mostraron una tendencia mayor a desescalar la terapia, en comparación con la observada en el personal subalterno (p = 0.002). CONCLUSIONES: Aunque los médicos tenían conciencia del problema de la resistencia a los antibióticos y los factores contribuyentes, su práctica no reflejó las medidas para reducirla. Se necesitan programas de educación continua y normas institucionales específicas para la prescripción de antibióticos.

Dynamics of antibiotic usage in the intensive care unit at the University Hospital of the West Indies.

OBJECTIVE: To determine antibiotic usage patterns in the Intensive Care Unit (ICU) at the University Hospital of the West Indies (UHWI). METHOD: A cross-sectional, analytical study of consecutive patients admitted to the ICU was conducted between July and December 2007. Exclusion criteria were HIV-positive patients, patients < 12 years and those discharged or who died within 48 hours of admission. Data were collected from medical records, stored and analysed using the SPSS Version 12. RESULTS: Of the 150 eligible patients, 109 had complete data (73%). Mean age was 50.8 +/- 20.7 years, with mean APACHE II score of 15.6 +/- 6.7. Forty-five patients (41.3%) received prophylactic antibiotics, most commonly ceftriaxone (31.7%) and metronidazole (19.0%). Appropriate discontinuation within 24 hours occurred in only 11.1%. Two-thirds of patients (67.9%) were treated with empiric antibiotics, most commonly piperacillin/tazobactam (32.1%), ceftazidime (27.5%) or metronidazole (27.5%). Reasons for empiric choice were primarily coverage of organisms based on presumed source of sepsis (45.6%), and broad spectrum, high-powered coverage (23.5%). Courses ranged from 1 - 42 days and were adequate based on subsequent cultures in 71% of cases. Culture reports took between 2 - 8 days with a mean of 3.7 days to become available. De-escalation was practised in only 2 of 26 (7.7%) cases and intravenous to oral switch therapy in only 3.3%. Thirty-two (29.4%) patients died, with sepsis being a cause in 12 (37.5%). CONCLUSIONS: Improved attention to discontinuation of prophylactic antibiotics, appropriate duration of antibiotic courses and de-escalation are essential if the antibiotic practices in the ICU at the UHWI are to compare favourably with international recommendations.

A survey of physicians' knowledge and attitudes regarding antimicrobial resistance and antibiotic prescribing practices at the University Hospital of the West Indies.

OBJECTIVE: To identify physicians' knowledge and attitudes regarding antimicrobial resistance and antibiotic prescribing practices at the University Hospital of the West Indies (UHWI). METHODS: A cross-sectional survey of physicians at the UHWI was conducted between September 2008 and April 2009 using a 28-item, self-administered questionnaire. Eligible physicians from several specialities were identified from departmental rotas. RESULTS: A total of 174 physicians completed the questionnaire, a response rate of 73%. Most physicians considered antibiotic resistance to be an extremely important global problem (55%) but less significant nationally (35%). Factors identified as important in producing resistance included widespread use of antibiotics (91%), inappropriate empiric choices (79%) and use of broad-spectrum agents (70%). Hand-washing was not considered to be important in reducing resistance. Useful interventions included access to current information on local resistance patterns (90%), institutional specific antibiotic guidelines (89%) and educational programmes (89%). Antibiotic cycling (40%) and restriction (35%) were regarded as less helpful. Knowledge of resistance-prone antibiotics and specific resistant organisms at the UHWI was poor, except for methicillin-resistant Staphylococcus aureus (MRSA). Empiric therapy for common infections was appropriate in most cases, and antibiotic choices were guided by availability of drugs (89%) and patient factors such as renal disease or allergy (80%). Only 45% of physicians would de-escalate to a narrow-spectrum antibiotic guided by a microbiology report, and consultants were more likely to de-escalate therapy than junior staff (p = 0.002). CONCLUSIONS: Although physicians were aware of the problem of resistance to antibiotics and the contributory factors, their practice did not reflect measures to reduce it. Continuing educational programmes and institution-specific antibiotic prescribing guidelines are needed.

KpnBI is the prototype of a new family (IE) of bacterial type I restriction-modification system.

KpnBI is a restriction-modification (R-M) system recognized in the GM236 strain of Klebsiella pneumoniae. Here, the KpnBI modification genes were cloned into a plasmid using a modification expression screening method. The modification genes that consist of both hsdM (2631 bp) and hsdS (1344 bp) genes were identified on an 8.2 kb EcoRI chromosomal fragment. These two genes overlap by one base and share the same promoter located upstream of the hsdM gene. Using recently developed plasmid R-M tests and a computer program RM Search, the DNA recognition sequence for the KpnBI enzymes was identified as a new 8 nt sequence containing one degenerate base with a 6 nt spacer, CAAANNNNNNRTCA. From Dam methylation and HindIII sensitivity tests, the methylation loci were predicted to be the italicized third adenine in the 5' specific region and the adenine opposite the italicized thymine in the 3' specific region. Combined with previous sequence data for hsdR, we concluded that the KpnBI system is a typical type I R-M system. The deduced amino acid sequences of the three subunits of the KpnBI system show only limited homologies (25 to 33% identity) at best, to the four previously categorized type I families (IA, IB, IC, and ID). Furthermore, their identity scores to other uncharacterized putative genome type I sequences were 53% at maximum. Therefore, we propose that KpnBI is the prototype of a new 'type IE' family.