In 2011, a field study was conducted to assess drug resistance of gastro-intestinal nematodes in sheep flocks in Ontario, Canada. Benzimidazole resistance in Haemonchus contortus was assessed by ...genetic analysis of eggs; measurement of resistant allele percentages at codons 167, 198 and 200 in the β-tubulin gene was determined on pools of H. contortus eggs using pyrosequencing. Susceptibility to benzimidazoles in gastro-intestinal nematodes was also determined using a Faecal Egg Count Reduction Test (FECRT) and a Larval Development Assay (LDA). In total, 16 farms were assessed with the genetic test. Based on resistant allele frequencies, all of the farms (16/16) tested had benzimidazole resistance in H. contortus; the overall percentage of benzimidazole-resistant H. contortus (estimated prior to treatment using the Hardy–Weinberg formula) was 68.5%. The FECRT and LDA were performed on 11 and 13 farms, respectively. Resistance to fenbendazole was detected on 100% (11/11) of the farms where the FECRT was performed. The LDA revealed the presence of thiabendazole resistance in H. contortus in 92% (12/13) of the farms. Estimated percentages of resistant parasites in H. contortus populations obtained with the two biological tests and the genetic test were compared. The results of the genetic test were in agreement with the biological tests and confirmed that benzimidazole resistance in H. contortus is present in Ontario sheep flocks. Differences between the different methods of drug resistance detection are discussed in terms of cost, time and sampling.
Gastrointestinal nematodes (GIN) are a significant constraint to pasture-based sheep production worldwide. Anthelmintic resistance (AR) has been reported in most sheep-raising areas in the world, yet ...little is known about the AR status in Canada. This study was conducted to determine the frequency of AR in GIN in sheep flocks in Ontario, Canada. Forty-seven sheep flocks were enrolled in the study, and their level of parasitism was monitored monthly throughout a grazing season by analyzing owner-acquired fecal samples from 15 grazing lambs per flock. When the mean GIN fecal egg count (FEC) reached a threshold of 200 eggs per gram (epg), oral ivermectin was supplied to producers to check ivermectin efficacy; the reduction in mean FEC 14 days after ivermectin treatment was calculated. ‘Drench failure’ was defined as a reduction in mean FEC of <95%. In those flocks with apparent drench failure, researchers performed a Fecal Egg Count Reduction Test (FECRT), dividing sheep into 4 treatment groups (n=10–15): control (i.e. untreated), ivermectin, and, if sufficient numbers of animals – fenbendazole and levamisole. AR was defined as a reduction in mean FEC <95% and a lower 95% confidence interval <90%. Larval cultures were performed on pooled post-treatment FECRT samples. Larval Development Assays (LDAs) to detect the presence of resistance to thiabendazole and levamisole were performed prior to the ivermectin drench check on pooled owner-acquired fecal samples that reached the 200epg threshold. Approximately 89% (42/47) of the farms reached the FEC threshold of 200epg; 93% (39/42) of these farms performed an ivermectin drench check, and 88% (34/39) of these farms had drench failure. The FECRT was performed on 29 of the 34 farms. Resistance to ivermectin, fenbendazole and levamisole was demonstrated on 97% (28/29), 95% (19/20) and 6% (1/17) of the farms tested, respectively, with considerable variability in resistance levels among farms. Haemonchus sp. was the most commonly cultured parasite from post-treatment fecal samples. LDA results for 21 farms were available; of these, 14% (3/21) and 62% (13/21) had low and high levels of thiabendazole resistance, respectively, while none of the farms exhibited resistance to levamisole. Amongst these tested farms, resistance to both ivermectin and benzimidazoles was very common. These findings strongly suggest that AR, particularly in Haemonchus sp., is a serious problem in these sheep flocks. Thus, marked changes in GIN management need to be instituted immediately to mitigate a worsening situation.
The aim of the present study was to evaluate and compare both the immediate and delayed desensitizing effects of the Nd:YAG (neodymium-doped:yttrium aluminum garnet; Nd
:Y
Al
O
) laser with and ...without dentin bonding agent (DBA) on occlusal dentinal hypersensitivity (DH).
Twenty-one patients with a total of 117 chronic occlusal hypersensitive teeth were selected. Each subject had at least three hypersensitive teeth. These teeth were randomly allocated into three groups: group 1, DBA on the occlusal surface; group 2, Nd:YAG laser (1064-nm wavelength, 30 mJ of energy, 10 pulse/s, 60 seconds, two times); and group 3, Nd:YAG laser (1064-nm wavelength, 30 mJ of energy, 10 pulse/s, 60 seconds, two times) with DBA. Pain was assessed using a visual analog scale after stimulation of the sensitive teeth by using the sharp tip of an explorer and an air blast prior to treatment and immediately, one week, one month, and three months after treatment by one blinded examiner.
A significant reduction in occlusal DH occurred at all time points in all of the experimental groups. The three groups showed significant improvements in discomfort immediately after treatment and after one week (
<0.001), but the Nd:YAG laser with DBA group had greater efficacy when compared with the other groups. The Nd:YAG laser group and Nd:YAG laser with DBA group had no significant differences at one month and three months after treatment (
>0.05); however, their desensitizing efficacy was superior to the DBA group.
The Nd:YAG laser with DBA may be most effective in the long-term treatment of occlusal DH, although other measures also reduce DH.
The Gulf Coast Native (Native) breed of sheep among many others is identified as being relatively resistant to Haemonchus contortus, an abomasal nematode parasite of small ruminants. Understanding ...the mode of immune response that helps these breeds of sheep control infection could help design and implement appropriate control programs. In this experiment, the components of the immune response during the early infection period in resistant Native lambs were evaluated and compared with susceptible Suffolk breed of sheep. Groups (n=5) of six month old Native and Suffolk lambs were given infective larvae as one time (single) or trickle experimental infections. Fecal, blood, and serum samples were collected on days 0, 2, 7, 14 and 21 post-infection. Abomasal mucosa and regional lymph node samples were collected at the time of necropsy on days 14 and 21. There was no significant difference in number of worms recovered at necropsy but the ratio of adult versus larvae was significantly greater in single infected Suffolk than Native lambs. Native lambs had significantly greater numbers of mast cells and eosinophils in the abomasal mucosa and serum IgG production was significantly greater compared to Suffolk lambs. Native lambs also showed a trend of increased level of serum IgA and IgE compared to Suffolk lambs.
The present study was planned to detect the genes encoding carbapenemases, ESBLs and class 1 integron‐integrase among bacteria obtained from retail goat meat. Fermenting and non‐fermenting bacterial ...isolates (n = 57), recovered from 61 goat meat samples, were identified by 16S rRNA gene sequencing. Antimicrobial susceptibility of isolates was tested by the broth dilution method using ceftazidime, cefotaxime, meropenem and imipenem. Plasmids were isolated and tested for their physical characters. Plasmids were subjected to screening of carbapenemase, ESBL and intI1 gene. Conjugation assay was performed using blaNDM‐positive isolates as the donor, and Escherichia coli HB101 as the recipient. Isolates showed the high rates of resistance to ceftazidime (77·2%), cefotaxime (70·2%), meropenem (22·8%) and imipenem (17·5%). They showed variability in number and size (~1 to >20 kb) of plasmids. Among all, 1, 4, 13 and 31 isolates showed the blaKPC, blaNDM, blaSHV and blaTEM genes, respectively. The blaKPC‐2 gene was observed in one E. coli isolate. The blaNDM‐1 gene was detected in Stenotrophomonas maltophilia (n = 2), Acinetobacter baumannii (n = 1) and Ochrobactrum anthropi (n = 1) isolates. These isolates co‐harboured the blaTEM and blaSHV genes. The intI1 gene was detected in 22 (38·6%) isolates, and 16 of these isolates showed the carbapenemase and/or ESBL genes. The conjugative movement of blaNDM gene could not be proved after three repetitive mating experiments. The presence of genes encoding carbapenemases and ESBLs in bacteria from goat meat poses public health risks.
Significance and impact of the study: The emergence of carbapenemases and extended‐spectrum β‐lactamases (ESBLs) in bacteria has now become a global problem leading to failure of advanced antimicrobial therapy. We report for the first time the blaNDM‐1 gene in non‐fermenting Gram‐negative bacterial isolates, and the blaKPC‐2 gene in an Escherichia coli isolate from goat meat in India. The presence of carbapenemase genes in bacteria from goat meat develops serious concerns about public health and food safety. Analysis of genetic determinants of β‐lactam resistance in bacteria would be helpful to formulate a suitable control strategy.
Haemonchus contortus is one of the major nematode parasites causing substantial economic losses in small ruminant farming worldwide. Recently, effectiveness of anthelmintic treatment has decreased ...due to an increasing problem of nematode populations that have developed resistance to anthelmintics. Efforts to develop effective vaccines have had limited success. There are certain breeds of sheep that are relatively resistant to the parasite including Gulf Coast Native (Native) sheep. Understanding the protective nature of the immune response that helps these breeds of sheep control infection could enable the development of vaccines to enhance control programs. This experiment was designed to compare the immunological responses of resistant Native versus susceptible Suffolk sheep in order to identify the mechanisms responsible for this resistance. Immune responses were evaluated in naturally infected Native and Suffolk lambs that grazed pasture contaminated predominantly with H. contortus. Ten lambs of each breed grazed together for 42 days. Fecal, blood and serum samples were collected on 0, 2, 4, 7, 10, 14, 21, 28, 35 and 42 days of exposure. Five lambs of each breed were necropsied on day 35 and five on day 42 for nematode recovery and abomasal tissue sample collection. Throughout the course of infection, Native lambs had significantly lower FEC, significantly lower PCV reduction percent, and significantly higher serum IgE after day 14 and increased expression of IL-4 on day 10 post-exposure compared to Suffolk lambs. At both necropsy time points, Native lambs had significantly greater numbers of mucosal mast cells, eosinophils and globule leukocytes in abomasal mucosa than Suffolk lambs. Results indicated that Native lambs had a more pronounced immune response to infection with H. contortus than Suffolk lambs which may be responsible for the observed resistance to infection.
The present study was aimed to detect the carbapenemase, extended‐spectrum β‐lactamase (ESBL), and intI1 gene of class 1 integron among fermenting (n = 61) and nonfermenting (n = 10) bacterial ...isolates recovered from water samples (n = 128). Isolates were identified by 16S rRNA sequencing. These isolates showed reduced‐susceptibility to third‐generation cephalosporins and carbapenems. The isolates varied in number and size of plasmids (2 kb to >20 kb). Plasmid DNA screening showed 5·6, 7, 11·2 and 26·7% prevalence of blaKPC, blaNDM, blaSHV and blaTEM genes respectively. Diverse blaNDM (blaNDM‐1 and blaNDM‐4) and blaSHV subtypes (blaSHV‐2 and blaSHV‐11) were recorded, unlike the single allelic blaKPC (blaKPC‐2) and blaTEM (blaTEM‐1) gene. Of the total 27 bla‐gene‐producing bacterial isolates, seven isolates co‐harboured the carbapenemase genes (blaNDM or blaKPC or the both) along with the ESBL genes (blaSHV or blaTEM). The intI1 gene of class 1 integron was detected among 12 (44·4%) of ESBL‐ and/or carbapenemase‐harbouring isolates. Gene transferability was seen among four of the 10 Enterobacteriaceae donors. Carbapenemases and ESBLs with class 1 integron among aquatic environmental isolates raise the serious issue of the biosecurity and health of the ecosystem.
Significance and Impact of the Study
Anthropologically affected and polluted environment harbours the resistance threats, where a diverse bacterial species maintain, develop and exchange genetic determinants that constitute a risk to human and ecological health. The antimicrobial resistance (AMR) in Enterobacteriaceae and non‐Enterobacteriaceae bacteria caused the failure of the therapy of last resort (carbapenems) and thus lead to life‐threatening infections affecting public health. Surveillance and monitoring of AMR could be important for epidemiological, diagnostic testing and control of pathogens. This is a point‐prevalence study reporting the comparative occurrence and co‐occurrence of carbapenemase and extended‐spectrum β‐lactamase genes among fermenting and nonfermenting bacteria isolated from the aquatic environment in India.
Significance and Impact of the Study: Anthropologically affected and polluted environment harbours the resistance threats, where a diverse bacterial species maintain, develop and exchange genetic determinants that constitute a risk to human and ecological health. The antimicrobial resistance (AMR) in Enterobacteriaceae and non‐Enterobacteriaceae bacteria caused the failure of the therapy of last resort (carbapenems) and thus lead to life‐threatening infections affecting public health. Surveillance and monitoring of AMR could be important for epidemiological, diagnostic testing and control of pathogens. This is a point‐prevalence study reporting the comparative occurrence and co‐occurrence of carbapenemase and extended‐spectrum β‐lactamase genes among fermenting and nonfermenting bacteria isolated from the aquatic environment in India.
Arsenic, iron and nitrate coexist in groundwater at a wide range of concentrations in various regions of the world. This study aims at investigating the concurrent arsenic and iron removal by ...combining the advantages of nitrate removal in a sulphidogenic bioreactor. A laboratory-scale suspended growth reactor was used to assess the performance of mixed bacterial culture at different arsenic, iron and nitrate concentrations. A semi-batch reactor (SmBR) was operated for more than 400 days in anoxic conditions at 30 ± 4 °C with different influent arsenate (250–1000 µg/L as arsenic), iron (2.0 mg/L) and nitrate (100–250 mg/L) concentrations in simulated groundwater and HRT of 3–6 days. Effects of different electron donors to deliver removing power on arsenic, iron and nitrate were also investigated. Nitrate was completely removed at all tested concentrations, while concentration of arsenic and iron met drinking water standards. The reactor was also charged with actual groundwater containing arsenic (up to 226 µg/L) as well as iron (up to 8.3 mg/L) and was able to remove both the contaminants below drinking water standards after addition of sufficient amount of sulphate. Toxicity characteristics leaching procedure results indicated that leachate arsenic concentrations were below the maximum United States Environmental Protection Agency guideline value for arsenic and biosolids which did not impose any environmental hazard.
Graphical abstract
Neural substrates for estrogen regulation of glucose homeostasis remain unclear. Female rat dorsal vagal complex (DVC) A2 noradrenergic neurons are estrogen- and metabolic-sensitive. The ventromedial ...hypothalamic nucleus (VMN) is a key component of the brain network that governs counter-regulatory responses to insulin-induced hypoglycemia (IIH). Here, the selective estrogen receptor-alpha (ERα) or -beta (ERβ) antagonists MPP and PHTPP were administered separately to the caudal fourth ventricle to address the premise that these hindbrain ER variants exert distinctive control of VMN reactivity to IIH in the female sex. Data show that ERα governs hypoglycemic patterns of VMN astrocyte glycogen metabolic enzyme, e.g. glycogen synthase and phosphorylase protein expression, whereas ERβ mediates local glycogen breakdown. DVC ERs also regulate VMN neurotransmitter signaling of energy sufficiency γ-aminobutyric acid or deficiency nitric oxide, steroidogenic factor-1 during IIH. Neither hindbrain ER mediates IIH-associated diminution of VMN norepinephrine (NE) content. Both ERs oppose hypoglycemic hyperglucagonemia, while ERβ contributes to reduced corticosterone output. Outcomes reveal that input from the female hindbrain to the VMN is critical for energy reserve mobilization, metabolic transmitter signaling, and counter-regulatory hormone secretion during hypoglycemia, and that ERs control those cues. Evidence that VMN NE content is not controlled by hindbrain ERα or -β implies that these receptors may regulate VMN function via NE-independent mechanisms, or alternatively, that other neurotransmitter signals to the VMN may control local substrate receptivity to NE.
•Estrogen receptor-alpha (ERα) or -beta (ERβ) antagonist was injected icv to hypoglycemic female rat hindbrain (HB).•HB ERα governs ventromedial hypothalamic nucleus (VMN) glycogen enzyme protein levels; ERβ controls VMN glycogen mass.•HB ERs regulate VMN transmitters that signal metabolic stability, e.g. γ-aminobutyric acid and nitric oxide.•Hypoglycemic diminution of VMN norepinephrine content is HB ER-independent.•HB ERα and -β oppose hypoglycemic hyperglucagonemia, while ERβ suppresses corticosterone output.
Background Liver plays an essential role for transforming and clearing chemicals that may cause harmful effects to it. Sodium Valproate, renowned to be a potent antiepileptic drug, when taken in ...overdose may cause toxic effects to liver and other organs as well. Liver damage can be assessed with histological changes and measurement of enzymes produced by it. Objective To investigate the histological changes induced by different doses of Sodium Valproate ranging from 100-500 mg/kg/day and observe its correlation with liver enzymes level in serum. Method Three-months old albino rats were divided into six groups, five in each. Control group was treated with normal saline and rest five groups with Sodium Valproate in different doses 100, 200, 300, 400 and 500 mg/kg/day respectively. Then, liver of those experimented rats were examined histologically under the light microscope. Furthermore, Liver enzymes; Alanine Transaminase and Aspartate transaminase were measured to assess the micro-anatomical changes in liver. Result Distorted hepatic lobular architecture with aggregations of nuclei at certain interval was observed in the groups of higher doses; 300 mg/kg/day and above. However, accumulation of adipocytes was observed in all the Sodium Valproate treated rats unlike the control group. When compared the enzyme levels among the groups, it was found to be significantly increased in dose dependent manner. Besides, it also showed skin lesions in all rats treated with the dose 400 mg/kg/day and above. Conclusion Higher doses of Sodium Valproate; 300 mg/kg/day and above induces hepatotoxicity and skin lesions in adult albino rats.
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