27 research outputs found
Occurrence and antimicrobial drug resistance of potential bacterial pathogens from shellfish, including
Abstract The trade of mollusks and other shellfish play a significant role in the economy of Grenada. The objective of this study was to gather information on the presence of potential human pathogens in clams, oysters, queen conchs, and whelks (West Indian top shell), and to determine the antimicrobial susceptibility patterns of the bacterial isolates. A total of 110 shellfish consisting of 40 clams, 30 oysters, 20 queen conchs, and 20 whelks, was obtained from three different bays along Grenada's coast and examined for bacterial pathogens by culture of whole soft tissue, intestines, feces, and/or meat. Selective media, including thiosulfate-citrate-bile-sucrose agar, were used with the aim to isolate various bacteria, particularly the members of the Vibrionaceae family. The isolates obtained were identified based on phenotypic properties, including reactions obtained with the API bacterial identification strips. Of 59 isolates, 35 were identified with >80% probability, with the most prevalent being Vibrio alginolyticus (8), followed by Shewenella putrefaciens (6), an
Genotypes, Antibiotic Resistance, and ST-8 Genetic Clone in Campylobacter
Rectal swabs from 155 sheep and 252 goats from Grenada were evaluated to
determine the prevalence of Campylobacter spp., antibiotic resistance,
and multilocus sequence types. Fifteen Campylobacter isolates were obtained
(14 C. jejuni and 1 C. coli). The prevalence (3.7%) did not differ
significantly between sheep (4.5%) and goats (3.2%). Among the seven antimicrobials
tested, resistance was only detected for tetracycline (30.8%) and metronidazole (38.5%).
Campylobacter isolates showed no significant difference between sheep and goats for
type of antimicrobial resistance or percent of resistant isolates. Twelve of the isolates were
successfully genotyped consisting of four recognized clonal complexes and three novel sequence
types. Importantly, one isolate from one goat was identified as the C. jejuni sequence
type-8, a zoonotic and tetracycline-resistant clone reported to be a highly virulent clone
associated with ovine abortion in the USA. Although most samples were from comingled sheep
and goat production units, there were no shared sequence types between these two host species.
None of the sequence types identified in this study have previously been reported in poultry in Grenada,
suggesting sheep- and goat-specific Campylobacter clones in Grenada. This is the
first report of genotyping of Campylobacter isolates from sheep and goats in the Eastern Caribbean
Ion mobility spectrometry-mass spectrometry (IMS-MS) of small molecules: separating and assigning structures to ions
The phenomenon of ion mobility (IM), the movement/transport of charged particles under the influence of an electric field, was first observed in the early 20th Century and harnessed later in ion mobility spectrometry (IMS). There have been rapid advances in instrumental design, experimental methods, and theory together with contributions from computational chemistry and gas-phase ion chemistry, which have diversified the range of potential applications of contemporary IMS techniques. Whilst IMS-mass spectrometry (IMS-MS) has recently been recognized for having significant research/applied industrial potential and encompasses multi-/cross-disciplinary areas of science, the applications and impact from decades of research are only now beginning to be utilized for "small molecule" species. This review focuses on the application of IMS-MS to "small molecule" species typically used in drug discovery (100-500 Da) including an assessment of the limitations and possibilities of the technique. Potential future developments in instrumental design, experimental methods, and applications are addressed. The typical application of IMS-MS in relation to small molecules has been to separate species in fairly uniform molecular classes such as mixture analysis, including metabolites. Separation of similar species has historically been challenging using IMS as the resolving power, R, has been low (3-100) and the differences in collision cross-sections that could be measured have been relatively small, so instrument and method development has often focused on increasing resolving power. However, IMS-MS has a range of other potential applications that are examined in this review where it displays unique advantages, including: determination of small molecule structure from drift time, "small molecule" separation in achiral and chiral mixtures, improvement in selectivity, identification of carbohydrate isomers, metabonomics, and for understanding the size and shape of small molecules. This review provides a broad but selective overview of current literature, concentrating on IMS-MS, not solely IMS, and small molecule applications. © 2012 Wiley Periodicals, Inc
Polygenic prediction of educational attainment within and between families from genome-wide association analyses in 3 million individuals
We conduct a genome-wide association study (GWAS) of educational attainment (EA) in a sample of ~3 million individuals and identify 3,952 approximately uncorrelated genome-wide-significant single-nucleotide polymorphisms (SNPs). A genome-wide polygenic predictor, or polygenic index (PGI), explains 12-16% of EA variance and contributes to risk prediction for ten diseases. Direct effects (i.e., controlling for parental PGIs) explain roughly half the PGI's magnitude of association with EA and other phenotypes. The correlation between mate-pair PGIs is far too large to be consistent with phenotypic assortment alone, implying additional assortment on PGI-associated factors. In an additional GWAS of dominance deviations from the additive model, we identify no genome-wide-significant SNPs, and a separate X-chromosome additive GWAS identifies 57