Rapid detection and molecular epidemiology of ß-lactamase producing Enterobacteriaceae isolated from food animals and in-contact humans in Nigeria.

The emergence and spread of ß-lactamase-producing Enterobacteriaceae poses a significant threat to public health, necessitating the rapid detection and investigation of the molecular epidemiology of these pathogens. We modified a multiplex real-time (RT)-PCR to concurrently detect ß-lactamase genes (blaCTX-M, blaTEM, and blaSHV) and Enterobacteriaceae 16S ribosomal RNA. qPCR probes and primers were validated using control isolates, and the sensitivity and specificity assessed. The optimised multiplex qPCR was used to screen 220 non-clinical Enterobacteriaceae from food animals and in-contact humans in Southeast Nigeria selected on cefotaxime-supplemented agar plates. Binary logistic regression was used to explore factors associated with the presence of the blaTEM and blaSHV genes in these isolates, and a subset of isolates from matched sampling sites and host species were whole genome sequenced, and their antimicrobial resistance (AMR) and plasmid profiles determined. The sensitivity and specificity of the qPCR assay was 100%. All isolates (220/220) were positive for Enterobacteriaceae ribosomal 16S rRNA and blaCTX-M, while 66.4% (146/220) and 9% (20/220) were positive for blaTEM and blaSHV, respectively. The prevalence of blaTEM and blaSHV varied across different sampling sites (farm, animal market and abattoirs). Isolates from Abia state were more likely to harbour blaTEM (OR = 2.3, p = 0.04) and blaSHV (OR = 5.12,p = 0.01) than isolates from Ebonyi state; blaTEM was more likely to be detected in isolates from food animals than humans (OR = 2.34, p = 0.03), whereas the reverse was seen for blaSHV (OR = 7.23, p = 0.02). Furthermore, Klebsiella and Enterobacter isolates harboured more AMR genes than Escherichia coli, even though they were isolated from the same sample. We also identified pan resistant Klebsiella harbouring resistance to ten classes of antimicrobials and disinfectant. Therefore, we recommend ESKAPE pathogens are included in AMR surveillance in future and suggest qPCRs be utilised for rapid screening of Enterobacteriaceae from human and animal sources.

Detection of multidrug-resistant Campylobacter species from food-producing animals and humans in Nigeria: Public health implications and one health control measures.

Antimicrobial-resistant thermophilic Campylobacter species (TCS) pose tremendous public health problems because they are zoonotic, difficult to treat and usually harboured by food-producing animals (FPAs). This study ascertained the phenotypic antimicrobial resistance (AMR) in 56 phenotypically identified TCS from slaughtered cattle, poultry, and humans in Enugu State, Nigeria. The presence of selected AMR and virulence genes harboured by the animal and human isolates were also detected and compared in 36 PCR-confirmed Campylobacter species. All the 56 TCS were multidrug-resistant as none were susceptible to ampicillin, penicillin-G, amoxicillin-clavulanic acid, cephalothin and metronidazole. The isolates were 92.9 %, 62.5 %, 92.9 %, 42.9 %, 26.8 %, 25 %, 28.6 %, 53.7 %, 30.1 %, 32.1 % and 55.4 % resistant to ceftriaxone, nalidixic acid, cefotaxime, enrofloxacin, ciprofloxacin, streptomycin, gentamycin, erythromycin, azithromycin, chloramphenicol and tetracycline, respectively. The top four most effective classes of antimicrobials were aminoglycosides > macrolides > amphenicol > fluoroquinolones. The AMR genes detected and the percentage of the isolates that harboured them were: aadE-1 (33.3 %), aphA-3-1 (36.1 %), tetO (44.4%), Blaoxa-61 (61.1 %) and the multidrug efflux pump, cmeB (86.1%). Virulence genes detected and the corresponding percentage of TCS that harboured them were: cdtB (61.1 %), flaA (47.2 %), ciaB (38.9 %), and pldA (38.9 %). The cmeB was significantly detected in animal isolates (p = 0.018, OR = 5.1, CI = 0.7-6.6) while BlaOXA-61 predominated in human isolates (p = 0.019, OR = 6.2). Likewise, ciaB virulence gene was mostly detected (p = 0.019, OR = 6.4, CI = 1.3-25) in animal isolates. The findings underscore the roles of FPAs in the zoonotic dissemination of Campylobacter-associated AMR and virulence genes in the study area. This warrants the adoption of One Health control strategies to limit spread of the multidrug-resistant zoonotic Campylobacter species.

Environment and Genotype Influence Quantitative and Qualitative Variation in Condensed Tannins in Aspen.

Condensed tannins (CTs) are abundant, ecologically-relevant secondary metabolites in many plants, which respond to variables associated with anthropogenic environmental change. While many studies have reported how genetic and environmental factors affect CT concentrations, few have explored how they influence CT molecular structure. Here, using trembling aspen (Populus tremuloides) as a model organism, we report how foliar CT concentrations, polymer sizes, representation of procyanidins and prodelphinidins, and stereochemistry vary in response to changes in air temperature (warming and freeze damage), air composition (elevated CO2 and O3), soil quality (nutrients and microbiome), and herbivory (mammal and lepidopteran). Use of multiple aspen genotypes enabled assessment of genetic influences on aspen CTs. CT concentration and composition were analyzed by thiolysis-ultra high performance liquid chromatography/mass spectrometry in archived leaf samples from prior experiments. All environmental variables explored except for soil microbiome influenced both CT quantity and quality, with climate factors appearing to have larger effect magnitudes than herbivory. Climate, soil, and herbivory effects varied among genotypes, while air composition effects were consistent across genotypes. Considering that CT properties (concentrations and molecular structures) mediate functions at the organismal through ecosystem scales, intraspecific variation in responses of CT properties to environmental factors could provide a pathway through which environmental change exerts selective pressure on Populus populations. Future studies are needed to identify the molecular-level mechanisms by which environmental factors influence CT concentrations and structures, and to establish their ecological and evolutionary significance.

Phenotypic Variation in Phytochemical Defense of Trembling Aspen in Western North America: Genetics, Development, and Geography.

Trembling aspen (Populus tremuloides) is arguably the most important deciduous tree species in the Intermountain West of North America. There, as elsewhere in its range, aspen exhibits remarkable genetic variation in observable traits such as morphology and phenology. In contrast to Great Lakes populations, however, relatively little is known about phytochemical variation in western aspen. This survey of phytochemistry in western aspen was undertaken to assess how chemical expression varies among genotypes, cytotypes (diploid vs. triploid), and populations, and in response to development and mammalian browsing. We measured levels of foliar nitrogen, salicinoid phenolic glycosides (SPGs) and condensed tannins (CTs), as those constituents influence organismal interactions and ecosystem processes. Results revealed striking genotypic variation and considerable population variation, but minimal cytotype variation, in phytochemistry of western aspen. Levels of SPGs and nitrogen declined, whereas levels of CTs increased, with tree age. Browsed ramets had much higher levels of SPGs, and lower levels of CTs, than unbrowsed ramets of the same genotype. We then evaluated how composite chemical profiles of western aspen differ from those of Great Lakes aspen (assessed in earlier research). Interestingly, mature western aspen trees maintain much higher levels of SPGs, and lower levels of CTs, than Great Lakes aspen. Phenotypic variation in chemical composition of aspen - a foundation species - in the Intermountain West likely has important consequences for organismal interactions and forest ecosystem dynamics. Moreover, those consequences likely play out over spatial and temporal scales somewhat differently than have been documented for Great Lakes aspen.

Knowledge and practices regarding antibiotic use among small-scale poultry farmers in Enugu State, Nigeria.

This study examined the knowledge and practices regarding antibiotic use among small-scale poultry farmers in Enugu State, Nigeria. A multistage sampling technique was employed to select 88 poultry farmers. The interview schedule was used for data collection. Respondents' indices of knowledge of antibiotic use (KABU), antibiotic resistance (KABR) and antibiotic use practices (PABU) were determined. Binary logistic regression was performed to ascertain the effect of socio-demographics of respondents, knowledge of antibiotic use and knowledge of antibiotic resistance on the likelihood that farmers use antibiotics inappropriately. All poultry farmers studied used antibiotics for growth promotion, disease prevention, and treatment. The mean index of KABU was 0.54 with 48 % of the respondents having good KABU while the mean index of KABR was 0.65 and 70.5 % of the farmers had good KABR. The farmers' mean index of PABU was 0.47 and 83 % of them used antibiotics inappropriately. Farmers with good KABU (OR = 4.2; 95% CI = 1.030-17.222) and KABR (OR = 4.5; 95% CI = 1.258-15.791) were more likely to misuse antibiotics than those with poor knowledge. Antibiotics are routinely, and on many occasions inappropriately, used in small-scale poultry production in Enugu State, Nigeria. Antibiotics are valuable agents whose efficacy can only be preserved if they are handled with care. Training small-scale farmers will allow them to improve their knowledge and practices regarding antibiotic use.

An app with brief behavioural support to promote physical activity after a cancer diagnosis (APPROACH): study protocol for a pilot randomised controlled trial.

BACKGROUND: There are multiple health benefits from participating in physical activity after a cancer diagnosis, but many people living with and beyond cancer (LWBC) are not meeting physical activity guidelines. App-based interventions offer a promising platform for intervention delivery. This trial aims to pilot a theory-driven, app-based intervention that promotes brisk walking among people living with and beyond cancer. The primary aim is to investigate the feasibility and acceptability of study procedures before conducting a larger randomised controlled trial (RCT). METHODS: This is an individually randomised, two-armed pilot RCT. Patients with localised or metastatic breast, prostate, or colorectal cancer, who are aged 16 years or over, will be recruited from a single hospital site in South Yorkshire in the UK. The intervention includes an app designed to encourage brisk walking (Active 10) supplemented with habit-based behavioural support in the form of two brief telephone/video calls, an information leaflet, and walking planners. The primary outcomes will be feasibility and acceptability of the study procedures. Demographic and medical characteristics will be collected at baseline, through self-report and hospital records. Secondary outcomes for the pilot (assessed at 0 and 3 months) will be accelerometer measured and self-reported physical activity, body mass index (BMI) and waist circumference, and patient-reported outcomes of quality of life, fatigue, sleep, anxiety, depression, self-efficacy, and habit strength for walking. Qualitative interviews will explore experiences of participating or reasons for declining to participate. Parameters for the intended primary outcome measure (accelerometer measured average daily minutes of brisk walking (≥ 100 steps/min)) will inform a sample size calculation for the future RCT and a preliminary economic evaluation will be conducted. DISCUSSION: This pilot study will inform the design of a larger RCT to investigate the efficacy and cost-effectiveness of this intervention in people LWBC. TRIAL REGISTRATION: ISRCTN registry, ISRCTN18063498 . Registered 16 April 2021.

Reduction of the Adverse Impacts of Fungal Mycotoxin on Proximate Composition of Feed and Growth Performance in Broilers by Combined Adsorbents.

Synergistic interaction of adsorbents in reducing the adverse impacts of mycotoxin on performance and proximate composition of broiler feeds was investigated. Fungal growth was induced by sprinkling water on the feed. S. cerevisiae + bentonite, kaolin + bentonite or S. cerevisiea + kaolin adsorbent combinations (1.5 g/kg feed) were added and the feeds were stored in black polythene bags. An untreated group was kept as a positive control while fresh uncontaminated feed was used as a negative control. Mycotoxins were extracted from the feeds and quantified using reverse phase HPLC. Proximate composition, nutrient digestibility of the feeds, feed intake and weight gain of the broilers were measured. Deoxynivalenol (DON) concentration in the contaminated/untreated feed was 347 µg/kg while aflatoxin B1 (AFB1) was 34 µg/kg. Addition of bentonite and kaolin in the contaminated feed reduced AFB1 and DON to significantly lower levels. Feed intake and weight gain were low in the broilers fed the contaminated feed. The carbohydrate level was significantly (p < 0.05) reduced from 62.31 to 40.10%, crude protein digestibility dropped from 80.67 to 49.03% in the fresh feed and contaminated feed respectively. Addition of the adsorbents (S. cerevisiae and bentonite) significantly (p < 0.05) improved these parameters.

Root Secondary Metabolites in Populus tremuloides: Effects of Simulated Climate Warming, Defoliation, and Genotype.

Climate warming can influence interactions between plants and associated organisms by altering levels of plant secondary metabolites. In contrast to studies of elevated temperature on aboveground phytochemistry, the consequences of warming on root chemistry have received little attention. Herein, we investigated the effects of elevated temperature, defoliation, and genotype on root biomass and phenolic compounds in trembling aspen (Populus tremuloides). We grew saplings of three aspen genotypes under ambient or elevated temperatures (+4-6 °C), and defoliated (by 75%) half of the trees in each treatment. After 4 months, we harvested roots and determined their condensed tannin and salicinoid (phenolic glycoside) concentrations. Defoliation reduced root biomass, with a slightly larger impact under elevated, relative to ambient, temperature. Elevated temperature decreased condensed tannin concentrations by 21-43% across the various treatment combinations. Warming alone did not alter salicinoid concentrations but eliminated a small negative impact of defoliation on those compounds. Graphical vector analysis suggests that effects of warming and defoliation on condensed tannins and salicinoids were predominantly due to reduced biosynthesis of these metabolites in roots, rather than to changes in root biomass. In general, genotypes did not differ in their responses to temperature or temperature by defoliation interactions. Collectively, our results suggest that future climate warming will alter root phytochemistry, and that effects will vary among different classes of secondary metabolites and be influenced by concurrent ecological interactions such as herbivory. Temperature- and herbivory-mediated changes in root chemistry have the potential to influence belowground trophic interactions and soil nutrient dynamics.

Antimicrobial resistance in Escherichia coli isolates from frugivorous (Eidolon helvum) and insectivorous (Nycteris hispida) bats in Southeast Nigeria, with detection of CTX-M-15 producing isolates.

Thirty-five Escherichia coli isolates obtained from the liver, spleen and intestines of 180 frugivorous and insectivorous bats were investigated for antimicrobial resistance phenotypes/genotypes, prevalence of Extended-Spectrum beta-lactamase (ESBL) production, virulence gene detection and molecular typing. Eight (22.9 %) of the isolates were multidrug resistant (MDR). Two isolates were cefotaxime-resistant, ESBL-producers and harbored the blaCTX-M-15 gene; they belonged to ST10184-D and ST2178-B1 lineages. tet(A) gene was detected in all tetracycline-resistant isolates while int1 (n = 8) and blaTEM (n = 7) genes were also found. Thirty-three of the E. coli isolates were assigned to seven phylogenetic groups, with B1 (45.7 %) being predominant. Three isolates were enteropathogenic E. coli (EPEC) pathovars, containing the eae gene (with the variants gamma and iota), and lacking stx1/stx2 genes. Bats in Nigeria are possible reservoirs of potentially pathogenic MDR E. coli isolates which may be important in the ecology of antimicrobial resistance at the human-livestock-wildlife-environment interfaces. The study reinforces the importance of including wildlife in national antimicrobial resistance monitoring programmes.

Nonlinear responses of foliar phenylpropanoids to increasing O3 exposure: Ecological implications in a Populus model system.

Plant phenolic compounds (phenylpropanoids) act as defense chemicals against herbivores and can mediate ecosystem processes. Tropospheric ozone (O3) pollution alters concentrations of plant phenolics; however, little is known about how these phytochemicals respond to different levels of O3 exposure. Here, we investigated the effects of five different O3 exposure levels on foliar concentrations of phenylpropanoids (53 compounds in total) and antioxidative capacity in hybrid Populus (Populus euramericana cv. '74/76') saplings grown in the presence of high or low soil nitrogen (N) load. Increasing O3 exposure initially increased and then decreased total concentrations of phenolic compounds, revealing a biphasic exposure-response profile (hormetic zone: 1.1-36.3 ppm h AOT40). This biphasic response pattern was driven by changes in a subset of phenylpropanoids with high antioxidative capacity (e.g. condensed tannins) but not in phenolics with low antioxidative capacity (e.g. salicinoids). The O3 exposure-response relationships of some phenylpropanoids (e.g. flavonoids and chlorogenic acids) varied in response to soil N, with hormesis occurring in high N soil but not in low N soil. Collectively, our findings indicated that plant phenolic compounds exhibit nonlinear responses to increasing O3 exposure, and that the responses vary in relation to phenolic compound class, antioxidative capacity, and soil nitrogen conditions. Our findings further suggest that the impact of O3 on ecological processes mediated by phenolics will be concentration-dependent, highlighting the complexity of the ecological effects of ground-level O3 pollution.

Growing up aspen: ontogeny and trade-offs shape growth, defence and reproduction in a foundation species.

BACKGROUND AND AIMS: Intraspecific variation in foundation species of forest ecosystems can shape community and ecosystem properties, particularly when that variation has a genetic basis. Traits mediating interactions with other species are predicted by simple allocation models to follow ontogenetic patterns that are rarely studied in trees. The aim of this research was to identify the roles of genotype, ontogeny and genotypic trade-offs shaping growth, defence and reproduction in aspen. METHODS: We established a common garden replicating >500 aspen genets in Wisconsin, USA. Trees were measured through the juvenile period into the onset of reproduction, for growth, defence chemistry (phenolic glycosides and condensed tannins), nitrogen, extrafloral nectaries, leaf morphology (specific leaf area), flower production and foliar herbivory and disease. We also assayed the TOZ19 sex marker and heterozygosity at ten microsatellite loci. KEY RESULTS: We found high levels of genotypic variation for all traits, and high heritabilities for both the traits and their ontogenetic trajectories. Ontogeny strongly shaped intraspecific variation, and trade-offs among growth, defence and reproduction supported some predictions while contradicting others. Both direct resistance (chemical defence) and indirect defence (extrafloral nectaries) declined during the juvenile stage, prior to the onset of reproduction. Reproduction was higher in trees that were larger, male and had higher individual heterozygosity. Growth was diminished by genotypic allocation to both direct and indirect defence as well as to reproduction, but we found no evidence of trade-offs between defence and reproduction. CONCLUSIONS: Key traits affecting the ecological communities of aspen have high levels of genotypic variation and heritability, strong patterns of ontogeny and clear trade-offs among growth, defence and reproduction. The architecture of aspen's community genetics - its ontogeny, trade-offs and especially its great variability - is shaped by both its broad range and the diverse community of associates, and in turn further fosters that diversity.

Veterinary clinic surfaces as reservoirs of multi-drug- and biocide-resistant Gram-negative bacteria.

This cross-sectional study was carried out to determine the common Gram-negative bacteria (GNB) contaminating veterinary clinic environments, and to evaluate the susceptibility of the isolates to commonly used antibiotics and biocides. A total of 62 swab samples were collected from different frequently touched surfaces in the 4 veterinary clinics visited. The samples were processed for isolation and identification of GNB using standard microbiological procedures. The susceptibility of the isolates to disinfectants and antibiotics was determined using agar dilution and disc diffusion techniques, respectively. A total of 114 GNB were isolated from the 4 clinics with isolation rates of 21.9, 22.8, 23.7 and 31.6% in clinics A, B, C and D, respectively. The surfaces of treatment tables were more contaminated (16.7 %) than receptionist/clinician desks (15.8%), weighing balances (10.5 %), door handles (7.9 %), drip stands (7.9 %), handwashing basins (7.0 %) and client chairs (7.0%). The surface-contaminating isolates were distributed into 20 genera, with members of Enterobacteriaceae predominating (n=97). Fifty-nine per cent of the isolates were resistant to the disinfectant Septol, while 5.3 and 0.9% were resistant to Purit and Dettol disinfectants, respectively. Multiple drug resistance was observed among 99% of the isolates with approximately 100% resistance to beta-lactams. Phenotypic expression of extended-spectrum (3.5 %) and AmpC beta-lactamase (38.6 %) production was detected. These findings highlight the role of clinic environments in serving as reservoirs for potential pathogens and sources for the spread of multi-drug resistant GNB.

Molecular epidemiology, genetic diversity and antimicrobial resistance of Staphylococcus aureus isolated from chicken and pig carcasses, and carcass handlers.

The epidemiology of Staphylococcus aureus in food animals, associated products, and their zoonotic potential in Nigeria are poorly understood. This study aimed to provide data on the prevalence, genetic characteristics and antimicrobial resistance of S. aureus isolated from chicken and pig carcasses, and persons in contact with the carcasses at slaughterhouses in Nigeria. Surface swabs were collected randomly from 600 chicken and 600 pig carcasses. Nasal swabs were collected from 45 workers in chicken slaughterhouses and 45 pig slaughterhouse workers. S. aureus isolates were analyzed by spa typing. They were also examined for presence of the Panton-Valentine Leucocidin (PVL) and mecA genes, as well as for antimicrobial resistance phenotype. Overall, 53 S. aureus isolates were recovered (28 from chicken carcasses, 17 from pig carcasses, 5 from chicken carcass handlers and 3 from pig carcass handlers). Among the isolates, 19 (35.8%) were PVL-positive and 12 (22.6%) carried the mecA gene. The 53 isolates belonged to 19 spa types. The Based Upon Repeat Pattern (BURP) algorithm separated the isolates into 2 spa-clonal complexes (spa-CC) and 9 singletons including 2 novel spa types (t18345 and t18346). The clonal complexes (CC) detected were CC1, CC5, CC8, CC15, CC88 and CC152. CC15-related isolates represented by spa type t084 (32.1%) and CC5 represented by spa type t311 (35.3%) predominated among isolates from chicken carcasses/ handlers, and pig carcasses/ handlers, respectively. Multidrug resistance exhibited by all the CC except CC8, was observed among isolates from chicken carcasses (64.3%), pig carcasses (41.2%), handlers of chicken meat (40.0%) and handlers of pork (33.3%). All the CC showed varying degrees of resistance to tetracycline while CC15 and CC5 exhibited the highest resistance to sulphamethoxazole/trimethoprim and erythromycin, respectively. The predominant antimicrobial resistance pattern observed was penicillin-tetracycline-sulphamethoxazole/trimethoprim (PEN-TET-SXT). In conclusion, food animals processed in Enugu State in Southeast Nigeria are potential vehicles for transmission of PVL-positive multiple-drug resistant S. aureus and methicillin-resistant S. aureus from farm to slaughterhouse and potentially to the human population. Public health intervention programs at pre- and post-slaughter stages should be considered in Nigerian slaughterhouses.

Linking plant genes to insect communities: Identifying the genetic bases of plant traits and community composition.

Community genetics aims to understand the effects of intraspecific genetic variation on community composition and diversity, thereby connecting community ecology with evolutionary biology. Thus far, research has shown that plant genetics can underlie variation in the composition of associated communities (e.g., insects, lichen and endophytes), and those communities can therefore be considered as extended phenotypes. This work, however, has been conducted primarily at the plant genotype level and has not identified the key underlying genes. To address this gap, we used genome-wide association mapping with a population of 445 aspen (Populus tremuloides) genets to identify the genes governing variation in plant traits (defence chemistry, bud phenology, leaf morphology, growth) and insect community composition. We found 49 significant SNP associations in 13 Populus genes that are correlated with chemical defence compounds and insect community traits. Most notably, we identified an early nodulin-like protein that was associated with insect community diversity and the abundance of interacting foundation species (ants and aphids). These findings support the concept that particular plant traits are the mechanistic link between plant genes and the composition of associated insect communities. In putting the "genes" into "genes to ecosystems ecology", this work enhances understanding of the molecular genetic mechanisms that underlie plant-insect associations and the consequences thereof for the structure of ecological communities.

Analysis of condensed tannins in Populus spp. using reversed phase UPLC-PDA-(-)esi-MS following thiolytic depolymerisation.

INTRODUCTION: Condensed tannins (CTs) are proanthocyanidin heteropolymers that are widely distributed among plants. Their biochemical properties are determined by molecular structure (e.g. polymer size, hydroxylation, stereochemistry). In Populus, genetically and environmentally-determined CT concentrations have been related to ecological effects, while the potential role of CT molecular structure has received little attention. OBJECTIVE: Evaluate CT polymerisation, major constituent monomers, stereochemistry and overall content in Populus tremuloides foliage using ultra-high-performance liquid chromatography with photodiode array and mass spectrometry (UPLC-PDA-(-)esi-MS) detection following thiolytic depolymerisation of the CTs. METHODOLOGY: CTs were extracted from dried foliage of six P. tremuloides genotypes into methanol and thiolytically depolymerised into constituent monomers. Calibration standards were prepared by thiolysis of CT mixtures isolated from P. tremuloides foliage on Sephadex LH-20, followed by preparative high-performance liquid chromatography (HPLC). RESULTS: Populus tremuloides CTs contained predominantly repeating subunits of three putative stereoisomers each of catechin and gallocatechin. Linear calibrations for standards of these subunits and their thioethers (purities 44-87%, UPLC-(-)esi-MS) were generally stable over the course of 10 months. CT polymer size, hydroxylation, stereochemistry and concentrations differed among genotypes. CONCLUSION: This thiolysis-UPLC-PDA-(-)esiMS method was optimised for analysis of CT polymer size, hydroxylation, stereochemistry, and total concentration in Populus foliage. It revealed significant variation in each of these properties among P. tremuloides genotypes, and will facilitate evaluation of how environmental factors affect CT molecular structures.

Prevalence, toxigenic potential and antimicrobial susceptibility profile of Staphylococcus isolated from ready-to-eat meats.

AIM: An epidemiological surveillance for Staphylococci contamination of ready-to-eat (RTE) meats from Enugu State, Nigeria, was carried out to determine the prevalence, species distribution, toxigenic potential and antimicrobial susceptibility profile of the organisms and hence the microbiological and toxicological safety of the meats. MATERIALS AND METHODS: Isolation and phenotypic Staphylococcus detection were done according to standard microbiological methods. Phenotypic resistance to 17 commonly used antimicrobial agents was determined by disc diffusion method. Molecular characterization of the isolates to species level and detection of selected toxigenic and antimicrobial-resistance genes were done by PCR methods. RESULTS: Twenty-four (9.4%) of the 255 meat samples investigated were contaminated with Staphylococcus species. Twenty-four Staphylococcus isolates belonging to six species of coagulase-negative Staphylococcus (CoNS) were identified. Four (16.7%) isolates harbored genes coding for exfoliative toxin-A. Ten (41.7%) isolates were multidrug resistant, while mecA, tetK, mphC, ermT and ermC were the antimicrobial-resistance genes detected in the isolates. Meat samples sourced from motor parks (16.7%) and open markets (8.5%) were the most contaminated. CONCLUSION: 9.4% of RTE meats sampled were contaminated with toxigenic and multidrug resistance CoNS. Beef was the most contaminated RTE meat type and harbored all the toxigenic and most of the antibiotic-resistant genes detected. Meat samples from motor parks had the highest staphylococcal contamination (16.7%), while those from mechanic village had the least (2.4%). Majority (79.2%) of the isolates were not susceptible to fusidic acid but none exhibited antimicrobial-resistance to chloramphenicol, ciprofloxacin, linezolid or teicoplanin. Food safety authorities in the study area should work proactively to massively improve the hygienic practices of meat vendors; in order to limit staphylococcal contamination of RTE meats and the associated public health problems.

Detection and molecular characterisation of extended-spectrum ß-lactamase-producing enteric bacteria from pigs and chickens in Nsukka, Nigeria.

OBJECTIVES: This study screened chickens and pigs slaughtered for human consumption for the presence and characteristics of extended-spectrum ß-lactamase (ESBL)- and plasmid-encoded AmpC (pAmpC) ß-lactamase-producing enteric bacteria. METHODS: Faecal samples from 410 broiler chickens and 100 pigs were cultured on MacConkey agar supplemented with 2µg/mL cefotaxime. Antimicrobial resistance phenotypes of the recovered isolates were determined by disk diffusion. PCR and sequencing were performed to identify the ESBL and pAmpC gene variants and other associated resistance determinants. Genetic diversity of the isolates was analysed by phylotyping and multilocus sequence typing. RESULTS: ESBL-producing Escherichia coli, Klebsiella pneumoniae, Enterobacter asburiae and Providencia spp. were isolated from 17 (4.1%) and 2 (2.0%) of the samples from chickens and pigs, respectively. One pAmpC-producing E. coli isolate was obtained from a chicken. Resistance to tetracycline, trimethoprim/sulfamethoxazole, chloramphenicol and gentamicin was exhibited by 95%, 80%, 60% and 55% of the ESBL/pAmpC-producing strains, respectively. tet(A) and aac(3)-II were the predominant genes detected in tetracycline- and aminoglycoside-resistant strains, respectively. blaCTX-M, encoding CTX-M-15 (15 isolates) or CTX-M-1 variants (3 isolates), was present in all but one ESBL-producer, either alone or in combination with blaSHV and/or blaTEM. The remaining ESBL-producer, a Providencia spp. recovered from a chicken, harboured blaVEB. The only pAmpC-positive E. coli strain carried blaCMY-2. The 11 ESBL-producing E. coli strains belonged to five lineages (ST226-A, ST3625-B1, ST10-A, ST46-A and ST58-B1). CONCLUSIONS: Healthy chickens and pigs act as reservoirs of ESBL/pAmpC-producing enterobacteria that can potentially be transmitted to humans through direct contact or ingestion of contaminated meat.

Assessment of antimicrobial drug administration and antimicrobial residues in food animals in Enugu State, Nigeria.

Imprudent administration of antimicrobial drugs in food-producing animals can facilitate the development and spread of antimicrobial-resistant organisms and also enhance the occurrence of antimicrobial residue in animal products. This study was undertaken to assess antimicrobial drug administration to food animals in livestock farms in Enugu State and determine livestock farmers' awareness on the consequences of imprudent antimicrobial administration to food animals and finally the prevalence of antimicrobial drug residues in edible tissues of cattle and pigs in the state. Structured questionnaire was used to extract information on antimicrobial drug administration and consequences of irresponsible use of antimicrobials in food animals from 109 livestock farms/farmers randomly selected using multi-stage sampling technique. Premi® test technology (R-Biopharm, Germany) was used to screen for antimicrobial residues in edible tissues from 300 carcasses consisting of 165 cattle and 135 pigs slaughtered for human consumption in two major slaughterhouses in Enugu State. Tetracyclines (90.8%), penicillins and beta-lactams (89.9%), and aminoglycoside (57.8%) were the classes of antimicrobials most frequently administered to food animals in the farms surveyed. Withdrawal period was not observed in 65% of the farms. About 30% of cattle and 23% of pig carcasses screened contained detectable amounts of antimicrobial residues. There is widespread indiscriminate administration of antimicrobial drugs in food animals in Enugu State. This underscores the need for public enlightenment on prudent use of antimicrobial drugs in food-producing animals in order to preserve the therapeutic efficacy for sustainable livestock production and to safeguard human health.

Impact of peripheral immune status on central molecular responses to facial nerve axotomy.

When facial nerve axotomy (FNA) is performed on immunodeficient recombinase activating gene-2 knockout (RAG-2-/-) mice, there is greater facial motoneuron (FMN) death relative to wild type (WT) mice. Reconstituting RAG-2-/- mice with whole splenocytes rescues FMN survival after FNA, and CD4+ T cells specifically drive immune-mediated neuroprotection. Evidence suggests that immunodysregulation may contribute to motoneuron death in amyotrophic lateral sclerosis (ALS). Immunoreconstitution of RAG-2-/- mice with lymphocytes from the mutant superoxide dismutase (mSOD1) mouse model of ALS revealed that the mSOD1 whole splenocyte environment suppresses mSOD1 CD4+ T cell-mediated neuroprotection after FNA. The objective of the current study was to characterize the effect of CD4+ T cells on the central molecular response to FNA and then identify if mSOD1 whole splenocytes blocked these regulatory pathways. Gene expression profiles of the axotomized facial motor nucleus were assessed from RAG-2-/- mice immunoreconstituted with either CD4+ T cells or whole splenocytes from WT or mSOD1 donors. The findings indicate that immunodeficient mice have suppressed glial activation after axotomy, and cell transfer of WT CD4+ T cells rescues microenvironment responses. Additionally, mSOD1 whole splenocyte recipients exhibit an increased astrocyte activation response to FNA. In RAG-2-/- + mSOD1 whole splenocyte mice, an elevation of motoneuron-specific Fas cell death pathways is also observed. Altogether, these findings suggest that mSOD1 whole splenocytes do not suppress mSOD1 CD4+ T cell regulation of the microenvironment, and instead, mSOD1 whole splenocytes may promote motoneuron death by either promoting a neurotoxic astrocyte phenotype or inducing Fas-mediated cell death pathways. This study demonstrates that peripheral immune status significantly affects central responses to nerve injury. Future studies will elucidate the mechanisms by which mSOD1 whole splenocytes promote cell death and if inhibiting this mechanism can preserve motoneuron survival in injury and disease.

Diversity of Ochrobactrum species in food animals, antibiotic resistance phenotypes and polymorphisms in the blaOCH gene.

Twenty-six lactose non-fermenting, oxidase, urease and citrate-positive Gram-negative rods, isolated from broiler chickens, pigs and cattle at slaughter, were subjected to the matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry and 16S rDNA sequencing for identification. Susceptibility to 14 antimicrobials was determined by the disc diffusion method. Ochrobactrum isolates resistant to third-generation cephalosporins were PCR-screened for the presence of the Ochrobactrum anthropi ampC gene (blaOCH). A 547-bp internal segment of blaOCH in the Ochrobactrum spp isolates was amplified with a newly designed primer set, and a phylogenetic reconstruction based on the complete amino acid sequence of blaOCH obtained from nine Ochrobactrum strains in our collection and 20 O. anthropi available in the GenBank was undertaken. All the Ochrobactrum isolates were resistant to the expanded-spectrum beta-lactams and streptomycin. None of the isolates was resistant to imipenem while 41.7% to 50.0% of them were resistant to fluoroquinolones. The blaOCH gene was detected in 16 (66.7%) and 20 (83.3%) of the 24 Ochrobactrum isolates (O. intermedium/O. tritici species), using primers designed for O. anthropi and the newly designed primer set, respectively. Six blaOCH variants grouped into two divergent clusters were identified. This is the first report of the complete nucleotide sequence of the blaOCH gene in non-antropi Ochrobactrum species.