An illustrative ‘plug & play’ catastrophe model for groundwater flooding

Economic losses from natural catastrophes are substantial; e.g., US$130 billion in 2010. ‘Catastrophe models’ are stochastic event-set based models that simulate these risks and underpin their assessment in the insurance industry. Most catastrophe models are proprietary ’black boxes’, which limit the level of user interaction, but new regulations (Solvency II) require firms to understand better the assumptions upon which the calculations ultimately rest. Part of this greater transparency requires constraining where uncertainty originates, perhaps by interchanging components provided by rival model vendors in ’plug and play’ catastrophe models. The objective of this paper is to demonstrate a practical, accessible way in which this may be made possible. Specifically to do this the first, illustrative ‘plug and play’ model was created efficiently and effectively using OpenMI, a free ‘open-source’ model linking standard. In about 100 man-hours climate, groundwater flow, vulnerability, exposure and loss components were linked to output financial losses, i.e. occurrence exceedance probability (OEP) curves. Groundwater flooding near Marlborough (UK) is used for this proof of concept. Losses from this example dataset are small, about £.8 million for a 33 yr OEP, but groundwater is an important compounding factor in UK flooding and this is the first, albeit rudimentary, attempt to probabilistically model loss for this hazard. Selected components are swopped, and losses calculated to show how insights into the origin of uncertainty can be gained. Crucially, OpenMI has the future potential to operate online and shield valuable data within components whilst allowing them to be swopped. So, it has the potential to underpin a secure, open-source, practical framework of use to the insurance industry

Evolution of carbapenem resistance in Acinetobacter baumannii: An 18-year longitudinal study from a medical center in northern Taiwan

BackgroundCarbapenem-resistant Acinetobacter baumannii has emerged as an important cause of nosocomial infections with high morbidity and mortality. The carbapenemases, especially class D carbapenem-hydrolyzing oxacillinases (CHDLs), play an important role, but the relationship between their prevalence trend and carbapenem resistance remains unclear.Materials and methodsBetween 1995 and 2012, we collected 667 isolates of A. baumannii from a single medical center in northern Taiwan. Pulsed-field gel electrophoresis (PFGE) was used to determine clonality. Antimicrobial susceptibility was determined. Carbapenemase genes and associated genetic structures were detected by polymerase chain reaction.ResultsIsolates were heterogeneous on PFGE. Susceptibility to carbapenem decreased steadily over the study period from 88.1% (2001–2003) to <25% (2010–2012), whereas the isolates remained susceptible to colistin (nearly 100%) and partially susceptible to tigecycline (80%). Starting in 2001, isolates carrying the ISAba1-blaOXA-51-like allele were consistently identified. Isolates containing the transposons Tn2006 or Tn2008 first appeared in 2007 with increasing carriage rates from 17.5% (2007–2009) to 50.0% (2010–2012). The IS1008-ΔISAba3-blaOXA-58-like, blaOXA-72 and metallo-β-lactamase genes were detected only sporadically. Isolates carrying CHDL genes were resistant to multiple drugs, including carbapenem, but remained susceptible to colistin (100.0%).ConclusionIncreased carbapenem resistance in A. baumannii may be caused by the increased prevalence of isolates containing the ISAba1-blaOXA-51-like allele and the transposons Tn2006 and Tn2008

Difference in imipenem, meropenem, sulbactam, and colistin nonsusceptibility trends among three phenotypically undifferentiated Acinetobacter baumannii complex in a medical center in Taiwan, 1997–2007

BackgroundTo determine whether the susceptibilities and the trends of nonsusceptibility of imipenem, meropenem, sulbactam, and colistin differed among Acinetobacter baumannii, Acinetobacter genomic species 3 (AGS 3), and Acinetobacter genomic species 13TU (AGS 13TU) over 11 years.MethodsA total of 1,039 nonduplicate blood isolates of A baumannii complex from bacteremic patients between 1997 and 2007 were collected at Taipei Veterans General Hospital and were identified to the species level using a multiplex polymerase chain reaction method and sequence analysis of 16S–23S intergenic spacer. The minimal inhibitory concentrations of antibiotics were determined by the agar dilution method.ResultsThe nonsusceptibility rates of carbepenems and sulbactam were highest in A baumannii, which also showed a trend toward increasing rate of carbapenems nonsusceptibility over the 11-year period of the study. AGS 13TU had the highest nonsusceptible rate to colistin, comparably increasing trend of carbapenem nonsusceptiblity as that of A baumannii, and is the only species with increasing sulbactam nonsusceptibility. AGS 3 had the lowest rate of nonsusceptibility to all four antimicrobial agents.ConclusionAlthough A baumannii had the highest nonsusceptibility rate to imipenem, meropenem, and sulbactam over the years, the higher rate of colistin nonsusceptibility and the emergence of nonsusceptibility of carbapenems and sulbactam in AGS 13TU suggested that this species might cause a great problem in the near future

Functions of Some Capsular Polysaccharide Biosynthetic Genes in Klebsiella pneumoniae NTUH K-2044

The growing number of Klebsiella pneumoniae infections, commonly acquired in hospitals, has drawn great concern. It has been shown that the K1 and K2 capsular serotypes are the most detrimental strains, particularly to those with diabetes. The K1 cps (capsular polysaccharide) locus in the NTUH-2044 strain of the pyogenic liver abscess (PLA) K. pneumoniae has been identified recently, but little is known about the functions of the genes therein. Here we report characterization of a group of cps genes and their roles in the pathogenesis of K1 K. pneumoniae. By sequential gene deletion, the cps gene cluster was first re-delimited between genes galF and ugd, which serve as up- and down-stream ends, respectively. Eight gene products were characterized in vitro and in vivo to be involved in the syntheses of UDP-glucose, UDP-glucuronic acid and GDP-fucose building units. Twelve genes were identified as virulence factors based on the observation that their deletion mutants became avirulent or lost K1 antigenicity. Furthermore, deletion of kp3706, kp3709 or kp3712 (ΔwcaI, ΔwcaG or Δatf, respectively), which are all involved in fucose biosynthesis, led to a broad range of transcriptional suppression for 52 upstream genes. The genes suppressed include those coding for unknown regulatory membrane proteins and six multidrug efflux system proteins, as well as proteins required for the K1 CPS biosynthesis. In support of the suppression of multidrug efflux genes, we showed that these three mutants became more sensitive to antibiotics. Taken together, the results suggest that kp3706, kp3709 or kp3712 genes are strongly related to the pathogenesis of K. pneumoniae K1

Nosocomial nasal myiasis in an intubated patient

We report a case of nasal myiasis caused by Sarcophaga spp., noted during hospitalization. A 74-year-old man was admitted with non-ST-elevation myocardial infarction. The patient underwent coronary arterial bypass surgery and was then mechanically ventilated by means of a nasotracheal tube for the next 8 days. After extubation, a total of seven maggots were retrieved from both nostrils. The larvae were removed and reared to mature flies, which were identified as Sarcophaga peregrina. From the clinical course and the fly’s life cycle, it was concluded that the infestation was hospital-acquired

Bacteremia Due to Acinetobacter Genomic Species 10▿

Six patients with Acinetobacter genomic species 10 bacteremia were identified. The clinical features of the patients, phenotypic and genotypic identifications, antimicrobial susceptibilities, and genes flanking ISAba1 of the bacteria were described. The results revealed that this bacterium is a potentially lethal pathogen that can cause health care-associated infections in debilitated patients

Impact of Derepressed AmpC β-Lactamase ACT-9 on the Clinical Efficacy of Ertapenem▿

An in vivo development of Pantoea agglomerans mutants (isolates PA2 to PA4) with reduced ertapenem susceptibility from that of isolate PA1 was associated with an inadequate clinical response to ertapenem therapy. All four isolates harbored the blaACT-9 AmpC β-lactamase gene. However, a loss-of-function mutation in the ampD gene in PA2 to PA4, but not PA1, led to derepressed ACT-9. The reduced ertapenem susceptibility caused by derepressed ACT-9 was confirmed with an ampD knockout mutant of PA1

Polymerase chain reaction assay for the detection of Acinetobacter baumannii in endotracheal aspirates from patients in the intensive care unit

BackgroundWe aim to evaluate the efficacy of polymerase chain reaction (PCR) to detect Acinetobacter baumannii in endotracheal aspirates.MethodsEndotracheal aspirates and clinical data were collected from patients who were admitted to the intensive care unit of Taipei Veterans General Hospital between April 1 and August 31 in 2006. Bacterial isolates from endotracheal aspirate cultures were phenotypically identified as Acinetobacter calcoaceticus–A baumannii complex using the API ID 32GN system. The presence of A baumannii in the aspirate was also directly detected by multiplex PCR.ResultsTen of the 114 endotracheal aspirate cultures were positive for A calcoaceticus–A baumannii complex, and only nine of the isolates were confirmed as A baumannii by the multiplex PCR. Direct PCR detection showed that 40 (35.1%) of the endotracheal aspirates were positive for A baumannii. Using positive culture of A baumannii as the gold standard, the sensitivity of direct PCR detection was 100% (6 of 6), the specificity was 70.4% (38 of 54), the positive predictive value was 27.3% (6 of 22), and the negative predictive value (NPV) was 100% (38 of 38) among patients with A baumannii pneumonia. Among patients with A baumannii colonization, the sensitivity of direct PCR detection was 100% (3 of 3), the specificity was 70.6% (36 of 51), the positive predictive value was 16.7% (3 of 18), and the NPV was 100% (36 of 36).ConclusionDirect PCR detection of A baumannii in endotracheal aspirates has a high sensitivity and NPV as compared with culture-based methods. Further studies are needed to determine the clinical applicability of this rapid detection test