Antimicrobial Susceptibility and Multiplex PCR Screening of AmpC Genes From Isolates of Enterobacter cloacae, Citrobacter freundii, and Serratia marcescens

Background/PurposeThe emergence of multiple drug resistance in Enterobacteriaceae is of particular concern. The aim of this study was to evaluate the antimicrobial susceptibility and screen for the ampC gene in three members of the Enterobacteriaceae family (Enterobacter cloacae, Citrobacter freundii, and Serratia marcescens) found at Taichung Veterans General Hospital during the past 5 years using multiplex polymerase chain reaction (PCR).MethodsThe susceptibility of thirty isolates from each of the three Enterobacteriaceae family members to five antimicrobial agents (ceftazidime, flomoxef, imipenem, moxifloxacin, and colistin) was assessed. The susceptibility was analyzed by disk diffusion, screening and confirmatory tests for extended-spectrum β-lactamases (ESBL) and minimum inhibitory concentration tests according to the recommendations of the Clinical and Laboratory Standards Institute. The detection of ampC genes (3 families, including DHA, EBC and CIT) was performed by multiplex PCR. To detect the coexistence of ESBL genes, PCR was performed using five primer pairs: TEM, SHV, SHV-5, CTX-M-3, and CTX-M-14.ResultsOf the 90 isolates, 53 (58.9%) were positive in the screening test for ESBL. Resistance genes were detected in 12 (22.6%) of these isolates: ampC gene of DHA type in one E. cloacae isolate and EBC type in three E. cloacae isolates; ampC gene of CIT type in four C. freundii isolates; CTX-M-3-like in one C. freundii isolate and one S. marcescens isolate; TEM in three E. cloacae isolates, three C. freundii isolates and two S. marcescens isolates; SHV in one C. freundii isolate.ConclusionAntibiotic phenotypes cannot accurately distinguish the resistance mechanisms caused by ampC or ESBL, and especially in ESBL-ampC combinations. However, PCR is a useful technique for the identification of the different types of resistance genes

Reproducibility of measuring amniotic fluid index and single deepest vertical pool throughout gestation

Objective: The aim of this study is to assess the intraobserver and interobserver reproducibility of measurement of amniotic fluid index (AFI) and single deepest vertical pool (SDVP), also known as the maximal vertical pocket. Methods: A total of 175 fetuses were evaluated. For each fetus, two observers acquired duplicate sets of AFI and SDVP. Measurement differences were expressed as actual and percentage values. For all comparisons, Bland-Altman plots were used to compare differences, and limits of agreement were calculated. Results: Intraobserver and interobserver agreement remained fairly constant with gestation, both for AFI and SDVP. The intraobserver limits of agreement for AFI were -5.2 to 5 cm or -39% to 37%; whereas for SDVP, these were -2.6 to 2.4 cm or -52% to 48%. The interobserver limits of agreement for AFI measurement were -7.3 to 7.1 cm or -54% to 53% and for SDVP measurement were -2.5 to 2.5 cm or -51% to 52%. Intraobserver coefficient of variation for SDVP was 14% and for AFI was 19%; the interobserver coefficient was 19% for both AFI and SDVP. Conclusion: Limits of agreement for both methods are wide. The choice of method should be dictated by clinical considerations other than method reproducibilit

The Potential of Supported Cu2O and CuO Nanosystems in Photocatalytic H2 Production

We demonstrate for the first time that tailoring the system morphology by appropriate synthetic strategies is a key tool to achieve unprecedented performances of the Cu-O system in photo-activated H2 generation even in the absence of TiO2. In particular, we report on a chemical vapor deposition (CVD) approach to obtain copper oxide nanostructures. The systems were grown under O2-based atmospheres on HF etched Si(100) substrates at different temperatures starting from a CuII precursor, Cu(hfa)2\ub7TMEDA (hfa=1,1,1,5,5,5-hexafluoro- 2,4-pentanedionate, TMEDA=N,N,N\u2019,N\u2019-tetramethylethylenediamine), which has not been adopted to date in CVD routes to copper oxides

Effects of the Argentine ant venom on terrestrial amphibians

Invasive species have major impacts on biodiversity and are one of the primary causes of amphibian decline and extinction. Unlike other top ant invaders that negatively affect larger fauna via chemical defensive compounds, the Argentine ant (Linepithema humile) does not have a functional sting. Nonetheless, it deploys defensive compounds against competitors and adversaries. We estimated levels of ant aggression toward 3 native terrestrial amphibians by challenging juveniles in field ant trails and in lab ant foraging arenas. We measured the composition and quantities of toxin in L. humile by analyzing pygidial glands and whole-body contents. We examined the mechanisms of toxicity in juvenile amphibians by quantifying the toxin in amphibian tissues, searching for histological damages, and calculating toxic doses for each amphibian species. To determine the potential scope of the threat to amphibians, we used global databases to estimate the number, ranges, and conservation status of terrestrial amphibian species with ranges that overlap those of L. humile. Juvenile amphibians co-occurring spatially and temporally with L. humile die when they encounter L. humile on an ant trail. In the lab, when a juvenile amphibian came in contact with L. humile the ants reacted quickly to spray pygidial-gland venom onto the juveniles. Iridomyrmecin was the toxic compound in the spray. Following absorption, it accumulated in brain, kidney, and liver tissue. Toxic dose for amphibian was species dependent. Worldwide, an estimated 817 terrestrial amphibian species overlap in range with L. humile, and 6.2% of them are classified as threatened. Our findings highlight the high potential of L. humile venom to negatively affect amphibian juveniles and provide a basis for exploring the largely overlooked impacts this ant has in its wide invasive range.This research was partially supported by the Norman and Rose Lederrer Endowed Chair of Biology to A.H. Additional funding came from MINECO and FEDER (projects CGL2012‐36181 and CGL2013‐43660‐P, respectively) and EBD (MINECO Severo Ochoa Program for Centers of Excellence in R + D + I [SEV‐2012‐0262])