Health and Social Services in Puerto Rico Before and After Hurricane Maria: Predisaster Conditions, Hurricane Damage, and Themes for Recovery.

"In September 2017, Puerto Rico was struck by two major hurricanes-Irma and Maria-that intensified existing challenges in Puerto Rico's health and social services infrastructure. In the aftermath, the government of Puerto Rico created a long-term recovery plan built on an evidence-based assessment of the damage from the hurricanes and the ongoing needs across Puerto Rico. Development of the recovery plan was supported by the Federal Emergency Management Agency, other federal agencies, local stakeholders, and analysis from the Homeland Security Operational Analysis Center (HSOAC), operated by RAND Corporation under contract with the U.S. Department of Homeland Security. HSOAC research provided the foundation for the 31 courses of action in the recovery plan addressing the health and social services sector. These actions are a mix of social, governmental, fiscal, and economic policies and reforms. This collection of actions presents an opportunity to build a more resilient health and social services infrastructure and regional health care networks to ensure reliable access to services, promote health and well-being, and more efficiently and effectively respond to public health crises and future disasters. The actions span the areas of health care, public health and emergency preparedness, environmental health, mental and behavioral health, and social services. The damage and needs assessment and courses of actions cover four major themes: building system capacity to respond both during disasters and routine times; strengthening the health and social services workforce; strengthening support services for at-need populations; and creating health-promoting communities.

Linking cohort-based data with electronic health records: a proof-of-concept methodological study in Hong Kong.

OBJECTIVES: Data linkage of cohort-based data and electronic health records (EHRs) has been practised in many countries, but in Hong Kong there is still a lack of such research. To expand the use of multisource data, we aimed to identify a feasible way of linking two cohorts with EHRs in Hong Kong. METHODS: Participants in the 'Children of 1997' birth cohort and the Chinese Early Development Instrument (CEDI) cohort were separated into several batches. The Hong Kong Identity Card Numbers (HKIDs) of each batch were then uploaded to the Hong Kong Clinical Data Analysis and Reporting System (CDARS) to retrieve EHRs. Within the same batch, each participant has a unique combination of date of birth and sex which can then be used for exact matching, as no HKID will be returned from CDARS. Raw data collected for the two cohorts were checked for the mismatched cases. After the matching, we conducted a simple descriptive analysis of attention deficit hyperactivity disorder (ADHD) information collected in the CEDI cohort via the Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale (SWAN) and EHRs. RESULTS: In total, 3473 and 910 HKIDs in the birth cohort and CEDI cohort were separated into 44 and 5 batches, respectively, and then submitted to the CDARS, with 100% and 97% being valid HKIDs respectively. The match rates were confirmed to be 100% and 99.75% after checking the cohort data. From our illustration using the ADHD information in the CEDI cohort, 36 (4.47%) individuals had ADHD-Combined score over the clinical cut-off in the SWAN survey, and 68 (8.31%) individuals had ADHD records in EHRs. CONCLUSIONS: Using date of birth and sex as identifiable variables, we were able to link the cohort data and EHRs with high match rates. This method will assist in the generation of databases for future multidisciplinary research using both cohort data and EHRs.

Psychometric evaluation of the Adjustment Disorder New Module-20 (ADNM-20): A multi-study analysis.

The Adjustment Disorder New Module (ADNM) is a self-report instrument for assessing Adjustment disorder (AjD), but uncertainties remain in evaluating factor structure and psychometric properties of ADNM in previous studies. Three studies were conducted to examine the factor structure, psychometrics properties, and clinical utility of the 20-item version of ADNM (ADNM-20) and 4-item version (ADNM-4) among samples of Hong Kong Chinese (N = 1,415). Confirmatory factor analysis demonstrated good model fitness with a bifactor model. Statistical indices indicated unidimensionality of AjD. The model-based reliability showed that the total score of ADNM-20 should be used in scoring and interpretation for capturing the construct of AjD. ADNM-4 model demonstrated full invariance between women and men and partial invariance between age groups. Receiver operating characteristic analysis revealed a cutoff score of 10 for probable AjD. The prevalence of probable AjD was 20.5 % excluding cases with probable depression among a population-representative sample of Hong Kong Chinese amid civil unrest in Hong Kong in July 2019. Cutoff scores of ADNM-20 (49) and ADNM-4 (9) were established for clinically significant common psychiatric conditions, namely PTSD, depression, and anxiety. Both ADNM-20 and ADNM-4 were reliable and valid to assess probable AjD. Implications for clinical research and practice are discussed.

Bioisosteric investigation of ebselen: Synthesis and in vitro characterization of 1,2-benzisothiazol-3(2H)-one derivatives as potent New Delhi metallo-ß-lactamase inhibitors.

Carbapenem-resistant Enterobacteriaceae (CRE) producing New Delhi metallo-ß-lactamase (NDM-1) cause untreatable bacterial infections, posing a significant threat to human health. In the present study, by employing the concept of bioisosteric replacement of the selenium moiety of ebselen, we have designed, synthesized and characterized a small compound library of 2-substituted 1,2-benzisothiazol-3(2H)-one derivatives and related compounds for evaluating their cytotoxicity and synergistic activity in combination with meropenem against the E. coli Tg1 (NDM-1) strain. The most promising compound 3a demonstrated potent synergistic activity against a panel of clinically isolated NDM-1 positive CRE strains with FICI as low as 0.09. Moreover, its IC50 value and inhibition mechanism were also confirmed by using the enzyme inhibition assay and the ESI-MS analysis respectively. Importantly, compound 3a has acceptable toxicity and is not a PAINS. Because of its structural simplicity and potent synergistic activity in combination with meropenem, we propose that compound 3a may be a promising meropenem adjuvant and a new series of such compounds may worth further investigations.

Effects of social support and depression on problematic drinking among trauma-exposed Chinese adults: A population-based study.

BACKGROUND: Alcohol consumption is prevalent and alcohol-related problems are a considerable social issue in China. Over 17% of Chinese consume alcohol regularly. Exposure to potentially traumatic events (PTE) is associated with increased alcohol-related problems. Social support often buffers this association. This study examined the relationship between exposure to PTE and alcohol misuse and explored the moderating effect of social support on this relationship in a Chinese context. METHODS: Data were collected through face-to-face computer assisted interviews in a stratified cluster sample of 753 Chinese adults living in Guangzhou, China. The Life Events Checklist-5 (LEC-5), World Health Organization Alcohol Use Disorders Identification Test (WHO-AUDIT), and Social Support Rating Scale (SSRS) were used to measure trauma exposure, problematic alcohol use, and social support. RESULTS: Univariable logistic regression analyses indicated that trauma exposure (OR = 3.18; compared to non-exposure), increased depression (OR = 1.06), and perceived friend support (OR = 1.21), were associated with higher odds of problematic drinking. Multivariable models adjusting for potential confounders demonstrated that PTE and depression were associated with problematic drinking, but this was not the case for perceived friend support. Perceived friend support modified the effect of trauma exposure and was associated with increased odds of problematic drinking among those who reported high levels of depressive symptoms. CONCLUSION: Social support may not always be a beneficial resource among those who experienced PTEs in a Chinese context. Further research is needed to better understand the role and function of different types of support, and for whom these associations are beneficial.

Barriers and Facilitators of Rapid HIV and Syphilis Testing Uptake Among Filipino Transnational Migrants in China.

Transnational migrant workers are known to be at high risk for HIV/STIs. This study estimated the point prevalence of HIV/syphilis and examined correlates of HIV/syphilis testing uptake among female migrant domestic workers in Macao, China. Data was obtained from 1363 female Filipino domestic workers who were offered free rapid HIV and syphilis testing. A mixed methods analysis was undertaken to examine correlates of testing and themes about reasons for not testing. Among 1164 women tested, there were no cases of HIV/syphilis observed and 199 (14.6%) refused HIV/syphilis testing. Greater social integration (aOR 1.12; 95% CI 1.02-1.24), having more than one sexual partner (aOR 1.65; 95% CI 1.02-2.65), and longer working hours on the testing day (aOR 0.97; 95% CI 0.94-1.00), were associated with testing uptake. Among those who tested, the majority (> 70%) had never tested before, suggesting the need to improve testing outreach. Qualitative themes about reasons for not testing included low perceived need and insufficient time. Individual and structural testing barriers should be reduced to optimize HIV/STI testing in migrant populations.

Psychometric Validation of PHQ-9 and GAD-7 in Filipino Migrant Domestic Workers in Macao (SAR), China.

There are 500,000 female Filipino domestic workers worldwide. However, there are no validated instruments to assess common mental disorders in this population. The Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) are brief measures that could be effective screeners for depression and anxiety in domestic workers. This study aims to establish reliability and validity of the Filipino versions of the PHQ-9 and GAD-7. In Study 1, 131 domestic workers completed the PHQ-9, GAD-7, and other questionnaires with a test-retest interval of 10 days. Convergent validity was examined using measures of posttraumatic stress disorder, direct exposure to traumatic events, and rumination. Discriminant validity was assessed using measures of discrimination, pain, social support, and indirect exposure to traumatic events. In Study 2, criterion validity was established with another sample of domestic workers (N = 100) using clinician-administered Mini International Neuropsychiatric Interviews. Receiver operating characteristic (ROC) curve analysis was performed to evaluate diagnostic efficiency. Results showed acceptable and high internal consistency for PHQ-9 and GAD-7, respectively. Both had acceptable test-retest reliability. Convergent and discriminant validity were also established. ROC curve results demonstrated that optimal cut scores for PHQ-9 and GAD-7 are 6 and 7, respectively. The Filipino versions of PHQ-9 and GAD-7 are reliable and valid for use among Filipino domestic workers.

Psychometric validation of the PTSD Checklist-5 among female Filipino migrant workers.

Migrant populations are at increased risk for exposure to traumatic life events. Presently, there are no reliable and valid screening instruments for posttraumatic stress disorder (PTSD) among Filipino migrant workers, a population that numbers over 2.3 million worldwide. This study evaluated the psychometric properties of the PTSD Checklist for DSM-5 (PCL-5) in a sample of female Filipino migrant workers in Macao (SAR), China, in two studies. The first examined the reliability (internal and test-retest), convergent validity (with depression, anxiety, and rumination), and discriminant validity (with pain and social support) in a sample of 131 participants. The second study established criterion validity of the PCL-5 using the PTSD module of the Mini-International Neuropsychiatric Interview (MINI), delivered by a female Filipino psychologist as the criterion, in a sample of 100 participants. Results indicated excellent internal consistency (Cronbach's alpha = 0.95) and moderate 10-day test-retest reliability (ρ = 0.58, p < .001). PCL-5 scores correlated strongly with scores on measures of depression (ρ = 0.71, p < .001), anxiety (ρ = 0.61, p < .001), and rumination (ρ = 0.68, p < .001), supporting convergent validity. Discriminant validity was demonstrated by a weaker association with scores on measures of pain (ρ = 0.33, p < .001) and social support (ρ = -0.11, p = .22). The diagnostic accuracy of the scale was good (AUC = 0.87). The optimal cutoff score of 25 optimized sensitivity (0.89) while maintaining adequate specificity (0.73), with a weighted Kappa of κ[1]) = 0.82. Our results demonstrated that the PCL-5 is a reliable and valid screening instrument for use among female Filipino migrant workers.

Las poblaciones migrantes tienen un mayor riesgo de exposición a eventos traumáticos en la vida. Actualmente, no hay instrumentos de detección fiables y válidos para el trastorno de estrés postraumático (TEPT) entre los trabajadores migrantes filipinos, una población que cuenta con más de 2,3 millones en todo el mundo. Este estudio evaluó las propiedades psicométricas de la Lista de chequeo-5 para TEPT según el DSM-5 (PCL-5) en una muestra de trabajadoras migrantes filipinas en Macao (SAR), China, en dos estudios. El primero examinó la confiabilidad (reevaluación interna y de prueba), la validez convergente (con depresión, ansiedad y rumiación) y la validez discriminante (con dolor y apoyo social) en una muestra de 131 participantes. El segundo estudio estableció la validez de criterio del PCL-5 utilizando el módulo TEPT de la Entrevista Internacional Neuropsiquiátrica Mini (MINI) aplicado por una psicóloga filipina como criterio, en una muestra de 100 participantes. Los resultados indicaron una excelente consistencia interna (alfa de Cronbach 0.95) y moderada fiabilidad de 10 días de prueba-reevaluación (ρ = 0.58, p <0.001). Las puntuaciones de PCL-5 se correlacionaron fuertemente con las puntuaciones en las medidas de depresión (ρ = 0.71, p <0.001), ansiedad (ρ = 0.61, p <0.001) y rumiación (ρ = 0.68, p <0.001), apoyando la validez convergente. La validez discriminante se demostró por una asociación más débil con las puntuaciones en las medidas del dolor (p= 0.33, p<0.001) y apoyo social (p= −0.11, p= 0.22).La precisión diagnóstica de la escala fue buena (AUC = 0.87). El punto de corte óptimo de 25 sensibilidad optimizada (0,89) manteniendo una especificidad adecuada (0,73), con un Kappa ponderado de κ [1]) = 0,82. Nuestros resultados demostraron que el PCL-5 es un instrumento de detección confiable y válido para el uso entre trabajadoras migrantes filipinas.

The effect of discrimination on depression and anxiety symptoms and the buffering role of social capital among female domestic workers in Macao, China.

Foreign migrant domestic workers experience an increased burden of mental disorders. Discrimination contributes to this burden. Social resources may buffer migrants from the effects of this discrimination. The present study explored the relationship between discrimination and common mental disorder (CMD) symptoms, anxiety and depression, and examined whether social capital (cognitive and structural) modified this association. A total of 131 female migrant Filipina domestic workers in Macao, China (Mage = 39.7) were sampled using snowball methods. Self-report data were obtained using tablet devices. Correlation analyses demonstrated that discrimination was significantly associated with depression (rs = 0.43) and anxiety (rs = 0.42). Mulitvariable regressions showed that cognitive, but not structural, social capital was significantly negatively associated with depression (ß = -0.30) and anxiety (ß = -0.32). Cognitive social capital modified the association between discrimination and depression (ß = 0.39) and anxiety (ß = 0.53). Contrary to predictions, as discrimination increased, compared to those with no cognitive social capital, those with moderate or high levels of cognitive social capital experienced worsening CMD symptoms. This finding provides greater nuance to our understanding of how and under what circumstances social resources are protective for mental health for migrant workers.

Boosting the efficacy of anti-MRSA ß-lactam antibiotics via an easily accessible, non-cytotoxic and orally bioavailable FtsZ inhibitor.

The rapid emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains has undermined the therapeutic efficacy of existing ß-lactam antibiotics (BLAs), prompting an urgent need to discover novel BLAs adjuvants that can potentiate their anti-MRSA activities. In this study, cytotoxicity and antibacterial screening of a focused compound library enabled us to identify a compound, namely 28, which exhibited low cytotoxicity against normal cells and robust in vitro bactericidal synergy with different classes of BLAs against a panel of multidrug-resistant clinical MRSA isolates. A series of biochemical assays and microscopic studies have revealed that compound 28 is likely to interact with the S. aureus FtsZ protein at the T7-loop binding pocket and inhibit polymerization of FtsZ protein without interfering with its GTPase activity, resulting in extensive delocalization of Z-ring and morphological changes characterized by significant enlargement of the bacterial cell. Animal studies demonstrated that compound 28 had a favorable pharmacokinetic profile and exhibited potent synergistic efficacy with cefuroxime antibiotic in a murine systemic infection model of MRSA. Overall, compound 28 represents a promising lead of FtsZ inhibitor for further development of efficacious BLAs adjuvants to treat the staphylococcal infection.

Correlates of expected eMental Health intervention uptake among Filipino domestic workers in China.

BACKGROUND: Transnational migrant populations face critical barriers to mental health service utilization that perpetuate mental health disparities globally. Overseas Filipino workers (OFWs) number over 2 million globally and 25% are female domestic workers. Structural barriers prevent equitable access to mental health services for this population. Electronic mental health (eMental Health) intervention is a scalable alternative to face-to-face treatment. The current study sought to identify key correlates of intention to use eMental Health within a community of female Filipino domestic workers living and working in Macao (SAR), China. METHODS: Respondent-driven sampling implemented at a community field site was used to reach a sample of 1364 female domestic workers. A multivariable adjusted partial proportional-odds (PPO) model was used to assess relevant correlates of intent to use eMental Health. RESULTS: The majority (62.8%) reported being likely to utilize eMental Health. The adjusted PPO model showed that younger age (18-25, 26-35, 36-45 v. over 55), longer time as an OFW, being likely (v. neutral and unlikely) to seek professional services, willingness to pay for services (v. not), belief that mental health services are a priority (v. low priority), having access to Wi-Fi outside the employer's home (v. not), and higher levels of social support were associated with increased odds of intent to use eMental Health. CONCLUSIONS: eMental Health is a promising intervention with high potential for uptake among OFWs. The majority of the study population owned a smartphone and were able to connect to the Internet or Wi-Fi. Future work will rigorously evaluate eMental Health programs for use among OFWs.

Investigation of synergistic antimicrobial effects of the drug combinations of meropenem and 1,2-benzisoselenazol-3(2H)-one derivatives on carbapenem-resistant Enterobacteriaceae producing NDM-1.

The worldwide prevalence of NDM-1-producing bacteria has drastically undermined the clinical efficacy of the last line antibiotic of carbapenems, prompting a need to devise effective strategy to preserve their clinical value. Our previous studies have shown that ebselen can restore the efficacy of meropenem against a laboratory strain that produces NDM-1. Here we report the construction of a focused compound library of 1,2-benzisoselenazol-3(2H)-one derivatives which comprise a total of forty-six candidate compounds. The structure-activity relationship of these compounds and their potential to serve as an adjuvant to enhance the antimicrobial efficacy of meropenem against a collection of clinical NDM-1-producing carbapenem-resistant Enterobacteriaceae isolates was examined. Drug combination assays indicated that these derivatives exhibited synergistic antimicrobial activity when used along with meropenem, effectively restoring the activity of carbapenems against the resistant strains tested in a Galleria mellonella larvae in vivo infection model. The mode of inhibition of one compound, namely 11_a38, which was depicted when tested on the purified NDM-1 enzyme, indicated that it could covalently bind to the enzyme and displaced one zinc ion from the active site. Overall, this study provides a novel 1,2-benzisoselenazol-3(2H)-one scaffold that exhibits strong synergistic antimicrobial activity with carbapenems, and low cytotoxicity. The prospect of application of such compounds as carbapenem adjuvants warrants further evaluation.

Assessing and Improving Hospital Mass-Casualty Preparedness: A No-Notice Exercise.

In recent years, mass-casualty incidents (MCIs) have become more frequent and deadly, while emergency department (ED) crowding has grown steadily worse and widespread. The ability of hospitals to implement an effective mass-casualty surge plan, immediately and expertly, has therefore never been more important. Yet, mass-casualty exercises tend to be highly choreographed, pre-scheduled events that provide limited insight into hospitals' true capacity to respond to a no-notice event under real-world conditions. To address this gap, the US Department of Health and Human Services (Washington, DC USA), Office of the Assistant Secretary for Preparedness and Response (ASPR), sponsored development of a set of tools meant to allow any hospital to run a real-time, no-notice exercise, focusing on the first hour and 15 minutes of a hospital's response to a sudden MCI, with the goals of minimizing burden, maximizing realism, and providing meaningful, outcome-oriented metrics to facilitate self-assessment. The resulting exercise, which was iteratively developed, piloted at nine hospitals nationwide, and completed in 2015, is now freely available for anyone to use or adapt. This report demonstrates the feasibility of implementing a no-notice exercise in the hospital setting and describes insights gained during the development process that might be helpful to future exercise developers. It also introduces the use of ED "immediate bed availability (IBA)" as an objective, dynamic measure of an ED's physical capacity for new arrivals. Waxman DA , Chan EW , Pillemer F , Smith TWJ , Abir M , Nelson C . Assessing and improving hospital mass-casualty preparedness: a no-notice exercise. Prehosp Disaster Med. 2017;32(6):662-666.

Development of a Novel Quantum Dots and Graphene Oxide Based FRET Assay for Rapid Detection of invA Gene of Salmonella.

A novel, rapid and simple fluorescence resonance energy transfer (FRET) based Salmonella specific gene, invA, detection system was developed, in which quantum dots (QDs) and graphene oxide (GO) worked as fluorescent donor and quencher, respectively. By measuring the fluorescence intensity signal, the Salmonella specific invA gene could be sensitively and specifically detected with a limit of detection (LOD) of ∼4 nM of the invA gene in 20 min. The developed system has the potential to be used for Salmonella detection in food and environmental samples and further developed into a platform for detection of other bacterial pathogens.

Efficient Synthesis of Amine-Linked 2,4,6-Trisubstituted Pyrimidines as a New Class of Bacterial FtsZ Inhibitors.

We have recently identified a new class of filamenting temperature-sensitive mutant Z (FtsZ)-interacting compounds that possess a 2,4,6-trisubstituted pyrimidine-quinuclidine scaffold with moderate antibacterial activity. Employing this scaffold as a molecular template, a compound library of amine-linked 2,4,6-trisubstituted pyrimidines with 99 candidates was successfully established by employing an efficient convergent synthesis designed to explore their structure-activity relationship. The results of minimum inhibitory concentration (MIC) assay against Staphylococcus aureus strains and cytotoxicity assay against the mouse L929 cell line identified those compounds with potent antistaphylococcal properties (MIC ranges from 3 to 8 µg/mL) and some extent of cytotoxicity against normal cells (IC50 ranges from 6 to 27 µM). Importantly, three compounds also exhibited potent antibacterial activities against nine clinically isolated methicillin-resistant S. aureus (MRSA) strains. One of the compounds, 14av_amine16, exhibited low spontaneous frequency of resistance, low toxicity against Galleria mellonella larvae, and the ability to rescue G. mellonella larvae (20% survival rate at a dosage of 100 mg/kg) infected with a lethal dose of MRSA ATCC 43300 strain. Biological characterization of compound 14av_amine16 by saturation transfer difference NMR, light scattering assay, and guanosine triphosphatase hydrolysis assay with purified S. aureus FtsZ protein verified that it interacted with the FtsZ protein. Such a property of FtsZ inhibitors was further confirmed by observing iconic filamentous cell phenotype and mislocalization of the Z-ring formation of Bacillus subtilis. Taken together, these 2,4,6-trisubstituted pyrimidine derivatives represent a novel scaffold of S. aureus FtsZ inhibitors.

Complete Sequence of a F33:A-:B- Conjugative Plasmid Carrying the oqxAB, fosA3, and blaCTX-M-55 Elements from a Foodborne Escherichia coli Strain.

This study reports the complete sequence of pE80, a conjugative IncFII plasmid recovered from an Escherichia coli strain isolated from chicken meat. This plasmid harbors multiple resistance determinants including oqxAB, fosA3, blaCTX-M-55, and blaTEM-1, and is a close variant of the recently reported p42-2 element, which was recovered from E. coli of veterinary source. Recovery of pE80 constitutes evidence that evolution or genetic re-arrangement of IncFII type plasmids residing in animal-borne organisms is an active event, which involves acquisition and integration of foreign resistance elements into the plasmid backbone. Dissemination of these plasmids may further compromise the effectiveness of current antimicrobial strategies.

Increased prevalence of carbapenem resistant Enterobacteriaceae in hospital setting due to cross-species transmission of the bla NDM-1 element and clonal spread of progenitor resistant strains.

This study investigated the transmission characteristics of carbapenem-resistant Enterobacteriaceae (CRE) strains collected from a hospital setting in China, in which consistent emergence of CRE strains were observable during the period of May 2013 to February 2014. Among the 45 CRE isolates tested, 21 (47%) strains were found to harbor the bla NDM-1 element, and the rest of 24 CRE strains were all positive for bla KPC-2. The 21 bla NDM-1-borne strains were found to comprise multiple Enterobacteriaceae species including nine Enterobacter cloacae, three Escherichia coli, three Citrobacter freundii, two Klebsiella pneumoniae, two Klebsiella oxytoca, and two Morganella morganii strains, indicating that cross-species transmission of bla NDM-1 is a common event. Genetic analyses by PFGE and MLST showed that, with the exception of E. coli and E. cloacae, strains belonging to the same species were often genetically unrelated. In addition to bla NDM-1, several CRE strains were also found to harbor the bla KPC-2, bla VIM-1, and bla IMP-4 elements. Conjugations experiments confirmed that the majority of carbapenem resistance determinants were transferable. Taken together, our findings suggest that transmission of mobile resistance elements among members of Enterobacteriaceae and clonal spread of CRE strains may contribute synergistically to a rapid increase in the population of CRE in clinical settings, prompting a need to implement more rigorous infection control measures to arrest such vicious transmission cycle in CRE-prevalent areas.

Functional categorization of carbapenemase-mediated resistance by a combined genotyping and two-tiered Modified Hodge Test approach.

The functional relationship between the detection of carbapenemase activity and phenotypic resistance in Gram-negative bacterial pathogens is often ill-defined. To address this issue, we developed a two-tiered Modified Hodge Test approach for carbapenemase detection and typing, in which the use of Pseudomonas aeruginosa strain PAO1 and Escherichia coli as indicator strains conferred two levels of sensitivities to carbapenemases. When applied alongside PCR genotyping tests for existence of known carbapenemase genes in 92 carbapenem resistant clinical isolates, this method is extremely useful in elucidating the relative role by which different enzymes contributed to the prevalent carbapenem-resistance phenotypes. With this study approach, we showed that the proportion of P. aeruginosa and Acinetobacter baumannii strains whose carbapenem resistance phenotypes could at least be partially attributed to carbapenemase were 34 and 89%, respectively. Our data also facilitates detailed functional categorization of carbapenem resistance phenotypes on the basis of the types and activities of detectable carbapenemase produced by the test organism. For example, six A. baumannii isolates harboring the bla OXA-51/23-like gene without detectable enzymatic activities were identified, suggesting that other resistance mechanisms may be involved. On the other hand, there were seven P. aeruginosa strains which produced carbapenemase phenotype without harboring known carbapenemase genes, inferring the existence of some hitherto unknown resistance determinants. Findings in this work therefore provide a comprehensive view on the cellular basis of carbapenem resistance phenotypes in major Gram-negative bacterial species, paving the way for development of novel strategies to reverse the effects of the major resistance mechanisms concerned.

Rapid Detection of K1 Hypervirulent Klebsiella pneumoniae by MALDI-TOF MS.

Hypervirulent strains of Klebsiella pneumoniae (hvKP) are genetic variants of K. pneumoniae which can cause life-threatening community-acquired infection in healthy individuals. Currently, methods for efficient differentiation between classic K. pneumoniae (cKP) and hvKP strains are not available, often causing delay in diagnosis and treatment of hvKP infections. To address this issue, we devised a Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) approach for rapid identification of K1 hvKP strains. Four standard algorithms, genetic algorithm (GA), support vector machine (SVM), supervised neural network (SNN), and quick classifier (QC), were tested for their power to differentiate between K1 and non-K1 strains, among which SVM was the most reliable algorithm. Analysis of the receiver operating characteristic curves of the interest peaks generated by the SVM model was found to confer highly accurate detection sensitivity and specificity, consistently producing distinguishable profiles for K1 hvKP and non-K1 strains. Of the 43 K. pneumoniae modeling strains tested by this approach, all were correctly identified as K1 hvKP and non-K1 capsule type. Of the 20 non-K1 and 17 K1 hvKP validation isolates, the accuracy of K1 hvKP and non-K1 identification was 94.1 and 90.0%, respectively, according to the SVM model. In summary, the MALDI-TOF MS approach can be applied alongside the conventional genotyping techniques to provide rapid and accurate diagnosis, and hence prompt treatment of infections caused by hvKP.

PMQR genes oqxAB and aac(6')Ib-cr accelerate the development of fluoroquinolone resistance in Salmonella typhimurium.

Emergence of multidrug-resistant Salmonella typhimurium strains, especially the ACSSuT and nalidixic acid R types, has significantly compromised the effectiveness of current strategies to control Salmonella infections, resulting in increased morbidity and mortality. Clinical S. typhimurium isolates recovered in Hong Kong during the period of 2005-2011 were increasingly resistant to ciprofloxacin (CIP) and antibiotics of the ACSSuT group. Our data revealed that oqxAB and aac(6')Ib-cr were encoded on plasmids of various sizes and the presence of these two elements together with a single gyrA mutation in S. typhimurium were sufficient to mediate resistance to CIP. Acquisition of the oqxAB and aac(6')Ib-cr encoding plasmids by S. typhimurium caused a fourfold increase in CIP minimal inhibitory concentration. Furthermore, the presence of oqxAB and aac(6')Ib-cr in Salmonella dramatically increased the mutation prevention concentration of CIP which may due to mutational changes in the drug target genes. In conclusion, possession of oqxAB and aac(6')Ib-cr encoding plasmid facilitate the selection of CIP resistant S. typhimurium, thereby causing a remarkable increase of CIP resistance among clinical Salmonella strains in Hong Kong.