Additive Bayesian networks for antimicrobial resistance and potential risk factors in non-typhoidal Salmonella isolates from layer hens in Uganda.

BACKGROUND: Multi-drug resistant bacteria are seen increasingly and there are gaps in our understanding of the complexity of antimicrobial resistance, partially due to a lack of appropriate statistical tools. This hampers efficient treatment, precludes determining appropriate intervention points and renders prevention very difficult. METHODS: We re-analysed data from a previous study using additive Bayesian networks. The data contained information on resistances against seven antimicrobials and seven potential risk factors from 86 non-typhoidal Salmonella isolates from laying hens in 46 farms in Uganda. RESULTS: The final graph contained 22 links between risk factors and antimicrobial resistances. Solely ampicillin resistance was linked to the vaccinating person and disposal of dead birds. Systematic associations between ampicillin and sulfamethoxazole/trimethoprim and chloramphenicol, which was also linked to sulfamethoxazole/trimethoprim were detected. Sulfamethoxazole/trimethoprim was also directly linked to ciprofloxacin and trimethoprim. Trimethoprim was linked to sulfonamide and ciprofloxacin, which was also linked to sulfonamide. Tetracycline was solely linked to ciprofloxacin. CONCLUSIONS: Although the results needs to be interpreted with caution due to a small data set, additive Bayesian network analysis allowed a description of a number of associations between the risk factors and antimicrobial resistances investigated.

Detection and Characterization of Streptomycin Resistance (strA-strB) in a Honeybee Gut Symbiont (Snodgrassella alvi) and the Associated Risk of Antibiotic Resistance Transfer.

Use of antibiotics in medicine and farming contributes to increasing numbers of antibiotic-resistant bacteria in diverse environments. The ability of antibiotic resistance genes (ARG) to transfer between bacteria genera contributes to this spread. It is difficult to directly link antibiotic exposure to the spread of ARG in a natural environment where environmental settings and study populations cannot be fully controlled. We used managed honeybees in environments with contrasting streptomycin exposure (USA: high exposure, Norway: low exposure) and mapped the prevalence and spread of transferrable streptomycin resistance genes. We found a high prevalence of strA-strB genes in the USA compared to Norway with 17/90 and 1/90 positive samples, respectively (p < 0.00007). We identified strA-strB genes on a transferrable transposon Tn5393 in the honeybee gut symbiont Snodgrassella alvi. Such transfer of resistance genes increases the risk of the spread to new environments as honeybees are moved to new pollination sites.

Geographically widespread honeybee-gut symbiont subgroups show locally distinct antibiotic-resistant patterns.

How long-term antibiotic treatment affects host bacterial associations is still largely unknown. The honeybee-gut microbiota has a simple composition, so we used this gut community to investigate how long-term antibiotic treatment affects host-associated microbiota. We investigated the phylogenetic relatedness, genomic content (GC percentage, genome size, number of genes and CRISPR) and antibiotic-resistant genes (ARG) for strains from two abundant members of the honeybee core gut microbiota (Gilliamella apicola and Snodgrassella alvi). Domesticated honeybees are subjected to geographically different management policies, so we used two research apiaries, representing different antibiotic treatment regimens in their apiculture: low antibiotic usage (Norway) and high antibiotic usage (Arizona, USA). We applied whole-genome shotgun sequencing on 48 G. apicola and 22 S. alvi. We identified three predominating subgroups of G. apicola in honeybees from both Norway and Arizona. For G. apicola, genetic content substantially varied between subgroups and distance similarity calculations showed similarity discrepancy between subgroups. Functional differences between subgroups, such as pectin-degrading enzymes (G. apicola), were also identified. In addition, we identified horizontal gene transfer (HGT) of transposon (Tn10)-associated tetracycline resistance (Tet B) across the G. apicola subgroups in the Arizonan honeybees, using interspace polymorphisms in the Tet B determinant. Our results support that honeybee-gut symbiont subgroups can resist long-term antibiotic treatment and maintain functionality through acquisition of geographically distinct antibiotic-resistant genes by HGT.

Association of the gut microbiota mobilome with hospital location and birth weight in preterm infants.

BackgroundThe preterm infant gut microbiota is vulnerable to different biotic and abiotic factors. Although the development of this microbiota has been extensively studied, the mobilome-i.e. the mobile genetic elements (MGEs) in the gut microbiota-has not been considered. Therefore, the aim of this study was to investigate the association of the mobilome with birth weight and hospital location in the preterm infant gut microbiota.MethodsThe data set consists of fecal samples from 62 preterm infants with and without necrotizing enterocolitis (NEC) from three different hospitals. We analyzed the gut microbiome by using 16S rRNA amplicon sequencing, shot-gun metagenome sequencing, and quantitative PCR. Predictive models and other data analyses were performed using MATLAB and QIIME.ResultSThe microbiota composition was significantly different between NEC-positive and NEC-negative infants and significantly different between hospitals. An operational taxanomic unit (OTU) showed strong positive and negative correlation with NEC and birth weight, respectively, whereas none showed significance for mode of delivery. Metagenome analyses revealed high levels of conjugative plasmids with MGEs and virulence genes. Results from quantitative PCR showed that the plasmid signature genes were significantly different between hospitals and in NEC-positive infants.ConclusionOur results point toward an association of the mobilome with hospital location in preterm infants.

Escherichia coli O78 isolated from septicemic lambs shows high pathogenicity in a zebrafish model.

The pathogenicity of Escherichia coli O78 strain K46, originally isolated from an outbreak of septicemia in neonatal lambs, was investigated in zebrafish embryo and murine models of infection. Its biofilm potential, cellulose production, and the expression of type 1 pili and curli fimbriae were measured by in vitro assays. The strain was highly pathogenic in the zebrafish embryo model of infection, where it killed all embryos within 24 h post inoculation (hpi) at doses as low as 1000 colony forming units. Zebrafish embryos inoculated with similar doses of commensal E. coli strains showed no signs of disease, and cleared the bacteria within 24 h. E. coli K46 colonized the murine gut at the same level as the uropathogenic E. coli (UPEC) reference strain CFT073 in CBA/J mice after oral inoculation, but infected the murine bladder significantly less than CFT073 after transurethral inoculation. Type 1 pili were clearly expressed by E. coli K46, while curli fimbriae and cellulose production were weakly expressed. The ability to produce biofilm varied in different growth media, but overall E. coli K46 was a poorer biofilm producer compared to the reference strain E. coli UTI89. In conclusion, the zebrafish lethality model provides further evidence that E. coli K46 is highly pathogenic and might be useful in future studies to identify bacterial virulence factors.

The metabolic impact of ß-hydroxybutyrate on neurotransmission: Reduced glycolysis mediates changes in calcium responses and KATP channel receptor sensitivity.

Glucose is the main energy substrate for neurons, and ketone bodies are known to be alternative substrates. However, the capacity of ketone bodies to support different neuronal functions is still unknown. Thus, a change in energy substrate from glucose alone to a combination of glucose and ß-hydroxybutyrate might change neuronal function as there is a known coupling between metabolism and neurotransmission. The purpose of this study was to shed light on the effects of the ketone body ß-hydroxybutyrate on glycolysis and neurotransmission in cultured murine glutamatergic neurons. Previous studies have shown an effect of ß-hydroxybutyrate on glucose metabolism, and the present study further specified this by showing attenuation of glycolysis when ß-hydroxybutyrate was present in these neurons. In addition, the NMDA receptor-induced calcium responses in the neurons were diminished in the presence of ß-hydroxybutyrate, whereas a direct effect of the ketone body on transmitter release was absent. However, the presence of ß-hydroxybutyrate augmented transmitter release induced by the KATP channel blocker glibenclamide, thus giving an indirect indication of the involvement of KATP channels in the effects of ketone bodies on transmitter release. Energy metabolism and neurotransmission are linked and involve ATP-sensitive potassium (KATP ) channels. However, it is still unclear how and to what degree available energy substrate affects this link. We investigated the effect of changing energy substrate from only glucose to a combination of glucose and R-ß-hydroxybutyrate in cultured neurons. Using the latter combination, glycolysis was diminished, NMDA receptor-induced calcium responses were lower, and the KATP channel blocker glibenclamide caused a higher transmitter release.

Antimicrobial resistance and antimicrobial resistance genes in marine bacteria from salmon aquaculture and non-aquaculture sites.

Antimicrobial resistance (AR) detected by disc diffusion and antimicrobial resistance genes detected by DNA hybridization and polymerase chain reaction with amplicon sequencing were studied in 124 marine bacterial isolates from a Chilean salmon aquaculture site and 76 from a site without aquaculture 8 km distant. Resistance to one or more antimicrobials was present in 81% of the isolates regardless of site. Resistance to tetracycline was most commonly encoded by tetA and tetG; to trimethoprim, by dfrA1, dfrA5 and dfrA12; to sulfamethizole, by sul1 and sul2; to amoxicillin, by blaTEM ; and to streptomycin, by strA-strB. Integron integrase intl1 was detected in 14 sul1-positive isolates, associated with aad9 gene cassettes in two from the aquaculture site. intl2 Integrase was only detected in three dfrA1-positive isolates from the aquaculture site and was not associated with gene cassettes in any. Of nine isolates tested for conjugation, two from the aquaculture site transferred AR determinants to Escherichia coli. High levels of AR in marine sediments from aquaculture and non-aquaculture sites suggest that dispersion of the large amounts of antimicrobials used in Chilean salmon aquaculture has created selective pressure in areas of the marine environment far removed from the initial site of use of these agents.

High stability of Stx2 phage in food and under food-processing conditions.

Bacteriophages (phages) carrying Shiga toxin genes constitute a major virulence attribute in enterohemorrhagic Escherichia coli (EHEC). Several EHEC outbreaks have been linked to food. The survival of such strains in different foods has received much attention, while the fate of the mobile Shiga toxin-converting phages (Stx phages) has been less studied. We have investigated the stability of an Stx phage in several food products and examined how storage, food processing, and disinfection influence the infectivity of phage particles. The study involved a recombinant Stx phage (Δstx::cat) of an E. coli O103:H25 strain from a Norwegian outbreak in 2006. Temperature, matrix, and time were factors of major importance for the stability of phage particles. Phages stored at cooling temperatures (4°C) showed a dramatic reduction in stability compared to those stored at room temperature. The importance of the matrix was evident at higher temperatures (60°C). Phages in ground beef were below the detection level when heated to 60°C for more than 10 min, while phages in broth exposed to the same heating conditions showed a 5-log-higher stability. The phages tolerated desiccation poorly but were infective for a substantial period of time in solutions. Under moist conditions, they also had a high ability to tolerate exposure to several disinfectants. In a dry-fermented sausage model, phages were shown to infect E. coli in situ. The results show that Stx phage particles can maintain their infectivity in foods and under food-processing conditions.

Putative virulence genes in Moritella viscosa: activity during in vitro inoculation and in vivo infection.

Moritella viscosa is considered to be the main aetiological agent of winter ulcer disease, primarily affecting farmed salmonid fish in cold marine waters. Transcription profiles of twelve M. viscosa genes, potentially involved in the pathogenesis, were studied during the course of an in vitro cell culture infection assay. Transcription of the same genes was compared in vivo, in head kidney and ulcer tissues of Atlantic salmon challenged with M. viscosa. During the in vitro infection, three putative toxins: a putative repeats in toxin gene (rtxA), a putative cytotoxic necrotizing factor (cnf) and a putative hemolysin increased their transcription significantly with time and coincident with cell rounding. Furthermore, the majority of the genes were stimulated by presence of fish cells and showed higher activity when adhered to fish cells compared to their planktonic counterpart. In vivo gene transcription studies revealed an up-regulation of a putative lateral flagellin in ulcer compared to head kidney tissues in the same individual. A similar trend was seen for cnf and a gene encoding a putative protease, indicating a role for these factors in colonization and tissue damage.

Availability of neurotransmitter glutamate is diminished when beta-hydroxybutyrate replaces glucose in cultured neurons.

Ketone bodies serve as alternative energy substrates for the brain in cases of low glucose availability such as during starvation or in patients treated with a ketogenic diet. The ketone bodies are metabolized via a distinct pathway confined to the mitochondria. We have compared metabolism of [2,4-(13)C]beta-hydroxybutyrate to that of [1,6-(13)C]glucose in cultured glutamatergic neurons and investigated the effect of neuronal activity focusing on the aspartate-glutamate homeostasis, an essential component of the excitatory activity in the brain. The amount of (13)C incorporation and cellular content was lower for glutamate and higher for aspartate in the presence of [2,4-(13)C]beta-hydroxybutyrate as opposed to [1,6-(13)C]glucose. Our results suggest that the change in aspartate-glutamate homeostasis is due to a decreased availability of NADH for cytosolic malate dehydrogenase and thus reduced malate-aspartate shuttle activity in neurons using beta-hydroxybutyrate. In the presence of glucose, the glutamate content decreased significantly upon activation of neurotransmitter release, whereas in the presence of only beta-hydroxybutyrate, no decrease in the glutamate content was observed. Thus, the fraction of the glutamate pool available for transmitter release was diminished when metabolizing beta-hydroxybutyrate, which is in line with the hypothesis of formation of transmitter glutamate via an obligatory involvement of the malate-aspartate shuttle.

Simultaneous quantification of high-dose naloxone and naloxone-3-ß-d-glucuronide in human plasma by UHPLC-MS/MS.

Aim: High-dose administration of the µ-opioid receptor inverse agonist naloxone (NX), has previously been demonstrated to reinstate nocifensive behavior in the late phase of inflammatory injuries. However, no current analytical methods can provide pharmacokinetic insight into the pharmacodynamic response of high-dose administration of NX. Materials & methods: Based on protein precipitation using 50 µl human plasma, NX and naloxone-ß-d-glucuronide (NXG) was analysed by UHPLC-MS/MS with 6 min cycle time. Results: A method for quantification of high-dose administered NX and NXG was developed and validated with intra- and interday precision and accuracy within ≤8.5% relative standard deviation (RSD) and -1.2-5.5% relative error (RE) for NX and ≤9.6% RSD and 0.6-6.5% RE for NXG. The method show excellent internal standard corrected matrix effects. Conclusion: A rapid UHPLC-MS/MS method was developed for quantification of NX and NXG in human plasma within 10-4000 ng/ml.

Diversity and Antimicrobial Resistance Genotypes in Non-Typhoidal Salmonella Isolates from Poultry Farms in Uganda.

Non-typhoidal Salmonella (NTS) are foodborne pathogens of global public health significance. The aim of this study was to subtype a collection of 85 NTS originating from poultry farms in Uganda, and to evaluate a subgroup of phenotypically resistant isolates for common antimicrobial resistance genes and associated integrons. All isolates were subtyped by pulsed-field gel electrophoresis (PFGE). Phenotypically resistant isolates (n = 54) were screened by PCR for the most relevant AMR genes corresponding to their phenotypic resistance pattern, and all 54 isolates were screened by PCR for the presence of integron class 1 and 2 encoding genes. These genes are known to commonly encode resistance to ampicillin, tetracycline, ciprofloxacin, trimethoprim, sulfonamide and chloramphenicol. PFGE revealed 15 pulsotypes representing 11 serotypes from 75 isolates, as 10 were non-typable. Thirty one (57.4%) of the 54 resistant isolates carried at least one of the seven genes (blaTEM-1,cmlA, tetA, qnrS,sul1,dhfrI,dhfrVII) identified by PCR and six (11%) carried class 1 integrons. This study has shown that a diversity of NTS-clones are present in Ugandan poultry farm settings, while at the same time similar NTS-clones occur in different farms and areas. The presence of resistance genes to important antimicrobials used in human and veterinary medicine has been demonstrated, hence the need to strengthen strategies to combat antimicrobial resistance at all levels.

Changes in brain levels of N-acylethanolamines and 2-arachidonoylglycerol in focal cerebral ischemia in mice.

The N-acylethanolamines (NAEs) and 2-arachidonoylglycerol (2-AG) are bioactive lipids that can modulate inflammatory responses and protect neurons against glutamatergic excitotoxicity. We have used a model of focal cerebral ischemia in young adult mice to investigate the relationship between focal cerebral ischemia and endogenous NAEs. Over the first 24 h after induction of permanent middle cerebral artery occlusion, we observed a time-dependent increase in all the investigated NAEs, except for anandamide. Moreover, we found an accumulation of 2-AG at 4 h that returned to basal level 12 h after induction of ischemia. Accumulation of NAEs did not depend on regulation of N-acylphosphatidylethanolamine-hydrolyzing phospholipase D or fatty acid amide hydrolase. Treatment with the fatty acid amide hydrolase inhibitor URB597 (cyclohexyl carbamic acid 3'-carbamoyl-biphenyl-3-yl ester; 1 mg/kg; i.p.) 1.5 h before arterial occlusion decreased the infarct volume in our model system. Our results suggest that NAEs and 2-AG may be involved in regulation of neuroprotection during focal cerebral ischemia in mice.

A Model-Based Approach for Joint Analysis of Pain Intensity and Opioid Consumption in Postoperative Pain.

Joint analysis of pain intensity and opioid consumption is encouraged in trials of postoperative pain. However, previous approaches have not appropriately addressed the complexity of their interrelation in time. In this study, we applied a non-linear mixed effects model to simultaneously study pain intensity and opioid consumption in a 4-h postoperative period for 44 patients undergoing percutaneous kidney stone surgery. Analysis was based on 748 Numerical Rating Scale (NRS) scores of pain intensity and 51 observed morphine and oxycodone dosing events. A joint model was developed to describe the recurrent pattern of four key phases determining the development of pain intensity and opioid consumption in time; (A) Distribution of pain intensity scores which followed a truncated Poisson distribution with time-dependent mean score ranging from 0.93 to 2.45; (B) Probability of transition to threshold pain levels (NRS ≥ 3) which was strongly dependent on previous pain levels ranging from 2.8-15.2% after NRS of 0-2; (C) Probability of requesting opioid when allowed (NRS ≥ 3) which was strongly correlated with the number of previous doses, ranging from 89.8% for requesting the first dose to 26.1% after three previous doses; (D) Reduction in pain scores after opioid dosing which was significantly related to the pain intensity at time of opioid request (P < 0.001). This study highlights the importance of analyzing pain intensity and opioid consumption in an integrated manner. Non-linear mixed effects modeling proved a valuable tool for analysis of interventions that affect pain intensity, probability of rescue dosing or the effect of opioids in the postoperative pain period.

Commensal E. coli Stx2 lysogens produce high levels of phages after spontaneous prophage induction.

Enterohemorrhagic E. coli (EHEC) is a food-borne pathogen that causes disease ranging from uncomplicated diarrhea to life-threatening hemolytic uremic syndrome (HUS) and nervous system complications. Shiga toxin 2 (Stx2) is the major virulence factor of EHEC and is critical for development of HUS. The genes encoding Stx2 are carried by lambdoid bacteriophages and the toxin production is tightly linked to the production of phages during lytic cycle. It has previously been suggested that commensal E. coli could amplify the production of Stx2-phages and contribute to the severity of disease. In this study we examined the susceptibility of commensal E. coli strains to the Stx2-converting phage ϕ734, isolated from a highly virulent EHEC O103:H25 (NIPH-11060424). Among 38 commensal E. coli strains from healthy children below 5 years, 15 were lysogenized by the ϕ734 phage, whereas lytic infection was not observed. Three of the commensal E. coli ϕ734 lysogens were tested for stability, and appeared stable and retained the phage for at least 10 cultural passages. When induced to enter lytic cycle by H2O2 treatment, 8 out of 13 commensal lysogens produced more ϕ734 phages than NIPH-11060424. Strikingly, five of them even spontaneously (non-induced) produced higher levels of phage than the H2O2 induced NIPH-11060424. An especially high frequency of HUS (60%) was seen among children infected by NIPH-11060424 during the outbreak in 2006. Based on our findings, a high Stx2 production by commensal E. coli lysogens cannot be ruled out as a contributor to the high frequency of HUS during this outbreak.

The gut bacterium Bacteroides thetaiotaomicron influences the virulence potential of the enterohemorrhagic Escherichia coli O103:H25.

Enterohemorrhagic E. coli (EHEC) is associated with severe gastrointestinal disease. Upon entering the gastrointestinal tract, EHEC is exposed to a fluctuating environment and a myriad of other bacterial species. To establish an infection, EHEC strains have to modulate their gene expression according to the GI tract environment. In order to explore the interspecies interactions between EHEC and an human intestinal commensal, the global gene expression profile was determined of EHEC O103:H25 (EHEC NIPH-11060424) co-cultured with B. thetaiotaomicron (CCUG 10774) or grown in the presence of spent medium from B. thetaiotaomicron. Microarray analysis revealed that approximately 1% of the EHEC NIPH-11060424 genes were significantly up-regulated both in co-culture (30 genes) and in the presence of spent medium (44 genes), and that the affected genes differed between the two conditions. In co-culture, genes encoding structural components of the type three secretion system were among the most affected genes with an almost 4-fold up-regulation, while the most affected genes in spent medium were involved in chemotaxis and were more than 3-fold up-regulated. The operons for type three secretion system (TTSS) are located on the Locus of enterocyte effacement (LEE) pathogenicity island, and qPCR showed that genes of all five operons (LEE1-LEE5) were up-regulated. Moreover, an increased adherence to HeLa cells was observed in EHEC NIPH-11060424 exposed to B. thetaiotaomicron. Expression of stx2 genes, encoding the main virulence factor of EHEC, was down-regulated in both conditions (co-culture/spent medium). These results show that expression of EHEC genes involved in colonization and virulence is modulated in response to direct interspecies contact between cells, or to diffusible factors released from B. thetaiotaomicron. Such interspecies interactions could allow the pathogen to recognize its predilection site and modulate its behaviour accordingly, thus increasing the efficiency of colonization of the colon mucosa, facilitating its persistence and increasing its virulence potential.

The commensal infant gut meta-mobilome as a potential reservoir for persistent multidrug resistance integrons.

Despite the accumulating knowledge on the development and establishment of the gut microbiota, its role as a reservoir for multidrug resistance is not well understood. This study investigated the prevalence and persistence patterns of an integrase gene (int1), used as a proxy for integrons (which often carry multiple antimicrobial resistance genes), in the fecal microbiota of 147 mothers and their children sampled longitudinally from birth to 2 years. The study showed the int1 gene was detected in 15% of the study population, and apparently more persistent than the microbial community structure itself. We found int1 to be persistent throughout the first two years of life, as well as between mothers and their 2-year-old children. Metagenome sequencing revealed integrons in the gut meta-mobilome that were associated with plasmids and multidrug resistance. In conclusion, the persistent nature of integrons in the infant gut microbiota makes it a potential reservoir of mobile multidrug resistance.

A recently introduced Dichelobacter nodosus strain caused an outbreak of footrot in Norway.

BACKGROUND: In 2008, an outbreak of ovine footrot occurred in Norway. Dichelobacter nodosus isolates collected between 2008 and 2011 have been characterised. Isolates defined as virulent by the gelatin gel test (GG-test) were only found in sheep in Rogaland County, where the severe cases of footrot were registered. The majority (96%) of the virulent isolates belonged to serogroup A. It is suspected that they represent a newly introduced strain, and the aim of the present study was to investigate whether they are genetically similar. Sixty-one virulent isolates from sheep and 116 benign isolates from sheep, cattle and goats were included. Four GG-test virulent isolates from Danish sheep were also included. All isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and by PCR for pgr variant determination. RESULTS: The Norwegian virulent isolates were assigned to 8 pulsotypes (PTs), while the benign isolates were assigned to 66 PTs. Thirty-seven (68.5%) of the 54, virulent, serogroup A isolates belonged to the same PT, and included isolates from 2008 through 2011. Isolates belonging to this PT were defined as the outbreak strain. The remaining virulent serogroup A isolates belonged to 4 PTs differing by ≤3 bands from the outbreak strain. Two virulent, Danish, serogroup A isolates differed by 2 bands from the Norwegian outbreak strain. All but 3 (95%) of the virulent isolates had the pgrA variant while 85% of the benign isolates had the pgrB variant. CONCLUSION: This study provides evidence that the footrot outbreak in Norway in 2008 most likely was caused by new introduction and local spread of one virulent D. nodosus strain.

Integrons in the intestinal microbiota as reservoirs for transmission of antibiotic resistance genes.

The human intestinal microbiota plays a major beneficial role in immune development and resistance to pathogens. The use of antibiotics, however, can cause the spread of antibiotic resistance genes within the resident intestinal microbiota. Important vectors for this are integrons. This review therefore focuses on the integrons in non-pathogenic bacteria as a potential source for the development and persistence of multidrug resistance. Integrons are a group of genetic elements which are assembly platforms that can capture specific gene cassettes and express them. Integrons in pathogenic bacteria have been extensively investigated, while integrons in the intestinal microbiota have not yet gained much attention. Knowledge of the integrons residing in the microbiota, however, can potentially aid in controlling the spread of antibiotic resistance genes to pathogens.

Characterization of Escherichia coli O78 from an outbreak of septicemia in lambs in Norway.

The aim of the study was to characterize isolates of Escherichia coli from an outbreak of septicemia in a Norwegian sheep flock in 2008 with emphasis on virulence, serological grouping, phylogenicity and homology. Six E. coli isolates from succumbed neonatal lambs and four E. coli isolates collected from healthy individuals were analyzed by Pulsed-Field Gel Electrophoresis (PFGE), miniaturized microarray, and polymerase chain reaction (PCR). The septicemic E. coli isolates showed identical pulsotypes (PTs), and belonged to serogroup O78, phylogenetic group A, and MLST ST 369. The virulence genes f17G, bmaE, afaE-VIII, ireA, iroN and iss were detected in the septicemic isolates. The results showed that the E. coli isolates from the septicemic outbreak had a clonal appearance, thus likely originating from a common source. The clone carried genes important for virulence, however, a significant explanation for the high pathogenicity was not revealed.