coli isolated from swine. Phenotypic antimicrobial tests showed that the E. coli isolate was resistant to the common antimicrobial agents used in farms and also exhibited reduced sensitivity to three indicator cephalosporins included in the study. Genetic analysis showed the presence of both TEM-20 and SHV β-lactamases that differed from SHV-1 only by a single amino acid substitution leucine to proline Selleck A 1155463 at position 138. This mutation was of special interest as SHV β-lactamses are specially related to K. pneumoniae and we wanted to see if this bla SHV gene

with single amino-acid substitution (L138P) detected in E. coli added to its substrate hydrolyzing Vorinostat activity [1, 2, 4, 22, 23]. All the cloned bla SHV genes expressed the specific protein bands that were confirmed by SDS-PAGE and Western blot. The size of the expressed SHV β-lactamases was larger than reported in previous research because of the intact 23 amino acid pro-peptide and His tag [20]. The enzyme kinetics of all the expressed β-lactamases showed differences in the affinities for penicillin and ampicillin that were included in this experiment (Table 3). The narrow spectrum β-lactamases SHV-1 and SHV-33 exhibited higher affinity to

penicillin and ampicillin respectively, whereas SHV-1 and SHV-33 selleck with only in one amino acid (L138P) mutation

exhibited reduced activity for both the substrate used in study. This indicated that leucine at position 138 was important for SHV β-lactamase and played an important role in hydrolyzing penicillin and ampicilin. Previous experiments on SHV β-lactamases have reported three natural mutations at position 69, 130 and 187 to be involved in conferring resistance to the inhibitors [11–13]. Proline has stronger stererochemical constraints than any other residues, with only one instead of two variable backbone angles and it lacks the normal amine backbone for hydrogen bonding. This could have the disruptive function Tangeritin to regular secondary structure and decreased the length of α-helix and changed the orientation of residues of binding sites. Based on the modeled docking structures of the wild-type and L138P mutant, the wild-type had three hydrogen bonds with penicillin and ampicillin but the L138P mutant had two hydrogen bonds, indicating that these structural changes by L138P mutation may decrease the substrate binding and finally resulted in reduced activity of L138P mutant. This result was supported by higher K m value for penicillin and ampicillin of L138P mutation when inserted in SHV-1 and SHV-33. Conclusions Based on our results we concluded that this mutation caused a drop in hydrolyzing penicillin and ampicillin.

(1) where ϕ = arctg M y /M x are the components of the vector . In this case, a distribution of the magnetization along the axis OY has the Bloch form: sinθ = ch −1(y/Δ), where θ is the polar angle in the chosen coordinate system. It is noted that it is the area which mainly contributes to m BP = Δ/γ 2 (γ is the gyromagnetic ratio) – the effective mass of BP [19]. It is natural to assume that the abovementioned PLK inhibitor region of the DW is an actual area of

BP. Taking into account Equation 1 and assuming that the motion of BP along the DW is an automodel form ϕ = ϕ(z − z 0, x), z 0 is the coordinate of the BP’s center), we can write after a series of transformations the energy of interaction of the Bloch point W H with the external magnetic field as follows: (2) where M S is the saturation magnetization. To describe the BP dynamics caused by magnetic field H and effective field of defect H d , we will use the Lagrangian formalism. In this case, using Equation 2 and the ‘potential energy’ in the Lagrangian function , we can write it in such form (3) Expanding

H d (z 0) in series in the vicinity of the defect position, its field can be presented in the following form: BIIB057 (4) where H c is the coercive force of a defect, d is the coordinate of its center, , D is the barrier width. It is reasonable to assume that the typical change of defect field is determined by a dimensional factor of given inhomogeneity. It is clear that in our case, and hence D ~ Λ. Note also that the abovementioned point

of view about defect Anacetrapib field correlates with the results of work [20], which indicate the dependence of coercive force of a defect on the characteristic size of the DW, vertical BL, or BP. Substituting Equation 4 into Equation 3, and taking into account that in the point z 0 = 0, the ‘potential energy’ W has a local metastable minimum (see Figure 1), we obtain the following expression: (5) where (we are considering the magnetic field values H close H c , that decreases significantly the height of the potential barrier). In addition, potential W(z 0) satisfies the normalization condition where z 0,1 = 0 and are the barrier coordinates. Figure 1 Potential caused by magnetic field H and effective field of defects H d . It should be mentioned that Equation 5 corresponds to the model potential proposed in articles [13–15] for the investigation of a tunneling of DW and vertical BL through the defect. Following GPCR & G Protein inhibitor further the general concepts of the Wentzel-Kramers-Brilloin (WKB) method, we define the tunneling amplitude P of the Bloch point by the formula where and ℏ is the Planck constant.

The electrochemical cycling was carried out between 1.5 and 3.0 V in C/10 rate for the initial three cycles and thereafter C/2 (1 C = 1,675 mA g−1 of sulfur). Results and discussion The pyrolytic decomposition of Fe-Pc and its adhesion on the spherical silica with a high surface area were described in Figure  1. The thermal decomposition of metal-phthalocyanine and other related compounds has been well studied before, especially to produce a nitrogen-doped graphitic carbon or carbon nano-tubes [18–21]. These were typically applied to fuel cells or metal air cells as an efficient oxygen reduction catalyst on the cathode [21, 22]. The decomposition of Fe-Pc occurs around

500°C to 600°C, where the ring starts to open to form an intermediate species which interacts with the adjacent silica surface, resulting in a selleck chemicals thin layer of the poorly ordered nitrogen-doped carbon on the surface at 600°C [23]. Around 900°C, the nitrogen contents of the carbon layer decrease, and the crystallinity of the graphene layers increases due to the catalytic act of metallic Fe nanoparticles. It is well known that the graphitic carbon from the decomposition of metal-phthalocyanine typically contains approximately 1% to 8% of nitrogen contents [22, 24]. Especially, Fe-Pc is known as an efficient carbon source for SCH727965 mouse producing a highly graphitic

carbon, where its Fe particles in the Metalloexopeptidase final product can be easily removed by simple acid leaching. Figure  2a,b shows the scanning electron microscope

(SEM) and transmission electron microscope (TEM) images of the mono-dispersed GHCS synthesized in this work. The diameter of these carbon spheres is around 460 to 480 nm which is just a little smaller than the size of the original silica sphere, and the wall thickness is less than 10 nm. From the N2 isotherm at 77 K (Figure  3), the BET surface area was measured to be 297 m2 g−1, and the pore size distribution deduced from the Barret-Joyner-Halenda algorithm indicates the presence of mesopores about 3.7 nm on the wall (Figure  3 inset). These pores can act as pathways for the impregnation of sulfur into the interior when sulfur/carbon nano-composite is formed [4, 12]. The graphitic nature of this wall was investigated by analyzing the XRD pattern and Raman spectra in Figure  2c,d respectively. The XRD pattern shows distinct (002) and (101) planes, and the full width at half maximum (FWHM) for (002) plane is 1.25°, which indicates the Vistusertib order formation of nano-crystallite with coherent length of 6.5 nm. The Raman spectrum shows D and G bands at 1,350 and 1,580 cm−1, respectively. They were deconvoluted using commercial software (IgorPro™, WaveMetrics, Inc., Lake Oswego) by fitting to Lorentzian functions. The ratio of the FWHM to D and G peaks is calculated to be 2.84 which is a much higher value than that for the carbon made from sucrose (2.

Methylation has implications in gene expression [66], and H. PSI-7977 mouse pylori associates with several pathologies that may result from different sets of expressed genes [67]. For instance, DNA methylation by M. HpyAIV

was shown to alter transcription of the catalase gene (katA) in H. pylori [68]. Further evidence is needed to understand if the high number Selleck VX-765 and diversity of MTases expressed among H. pylori strains is beneficial for the bacteria and/or plays any role in pathogenicity. Conclusion In conclusion, there is a clear association of some MTases with geographic groups of H. pylori strains, making them useful as geomarkers (Table 2). Indeed, other genes, as cagA or vacA, have allelic forms with particular geographic distributions [6, 8, 69]. Similar results are now observed for the majority strain-specific genes. M. HhaI and M. NaeI are common to all tested strains, which is consistent with the co-evolution theory of man and H. pylori [2, 3] and suggests that their presence in bacterial genome preceded the human diaspora out of Africa. Finally, the association of MTases with geographical bacterial clusters may be observed in other bacterial species, and may reveal to be https://www.selleckchem.com/products/blz945.html good geographic markers to trace bacterial evolution.

Methods H. pylori strains 221 H. pylori strains were isolated from different regions (Africa, America, Asia and Europe) (Table 4). Strains belong to the collections of the Helicobacter and Campylobacter Reference Center of the Portuguese National Institute of Health (INSA), the Helicobacter and Campylobacter National Reference Center (Victor Segalen University, Bordeaux, France) and the Medical Microbiology Institute of Hannover (Germany). Strains belonging to INSA and Helicobacter and Campylobacter National Reference Center were randomly selected, except in cases in which all strains available for each sub-sample group were analysed (strains with African origin). DNA from H. pylori Singapore strains was randomly selected from SSR128129E East Asia

H. pylori strain collection of the Medical Microbiology Institute of Hannover. Except for the country of origin, there is no further information about the ethnic group or ancestry of the human host providing the strain. Due to difficulty in obtaining strains from different geographic origins the number of strains from each continent is uneven. Table 4 Geographic origin of H. pylori strains. Continent Country Number of strains Percentage Europe   146 66.1   Portugal 106 48.0   France 11 5.0   United Kingdom a) 8 3.6   Germany 6 2.7   Sweden 9 4.1   Norway 6 2.7 Africa   38 17.2   Portuguese with African origin b) 20 9.0   Egypt 7 3.2   Burkina Faso 11 5.0 America   27 12.2   USA c) 1 0.5   Costa Rica 6 2.7   Mexico 6 2.7   Argentina 14 6.3 Asia   10 4.5   Singapore 10 4.5 Total   221 100.

At this point all of the internal organs of the insect have been converted into bacterial biomass. This

bioconversion is facilitated by a range of hydrolytic enzymes that are secreted by Photorhabdus, including proteases and lipases. In the presence of high densities of Photorhabdus the IJ is stimulated to recover to a self-fertile adult hermaphrodite and this is the start of nematode reproduction. The hermaphrodite lays eggs and the developing nematode larvae feed on the bacteria present in the insect. As in Caenorhabditis elegans, the Heterorhabditis nematodes develop through 4 juvenile stages (J1-J4) before becoming MG132 find more adults [3]. Nematode reproduction continues for 2-3 generations until unidentified environmental stimuli triggers the formation of an alternative J3 nematode, the IJ, which exits the insect cadaver. Before leaving the insect cadaver the new IJ must be colonized by Photorhabdus and transmission of the bacteria to the IJ is a complex process that has only recently been phenomonologically described [4]. There are 2 striking features associated with the transmission process: 1) the colonization of the rectal gland cells of the adult hermaphrodite by Photorhabdus and 2) the observation that all IJs develop inside the adult hermaphrodite in a process

called endotokia matricida. Therefore the bacteria that colonize the adult hermaphrodite are ultimately responsible for the colonization of the IJ [4]. The molecular mechanisms underlying the transmission see more process are poorly understood. In the only previous published study that reports a gene involved in transmission it was shown that a mutation in a gene annotated as pbgE1 severely affects the ability of Photorhabdus TCL to colonize the IJ [5]. This mutant was isolated during a screen for genes affecting swimming motility and

the pbgE1 mutant was also shown to be severely attenuated in virulence. The pbgE1 gene is predicted to be part of a 7 gene pbgPE operon that is homologous to the arn operon in Salmonella [5]. The arn operon has been shown to be involved in the modification of the lipid A moiety of LPS with L-aminoarabinose in response to the presence of cationic antimicrobial peptides (CAMPs) [6–8]. The pbgE1 mutant did produce altered LPS compared to the wild-type implicating LPS structure as a nematode colonization factor in Photorhabdus [5]. In this study we screened a library of Photorhabdus mutants with the aim of extending our understanding of the transmission process by identifying genes important in the colonization of the H. bacteriophora IJ nematode by P. luminescens TT01. Results Construction of a GFP-tagged strain of P.

To determine changes in cellular activity within tissues due to viable or non-viable MAP and the introduction of NP-51 we preformed assays to measure host transcript expression for key inflammatory markers. Host immune cells may produce and store non-specific, pro-inflammatory cytokines in the event of infection and yield more specific cytokines as disease progresses. For these reasons, our evaluation of cytokine transcript concentrations was to determine their active production, Geneticin mw post MAP infection. These results are highlighted in Figures 3 and 4, respectively. Figure 3 Serum

cytokine abundance relative to controls and associated with chronic MAP infection. Data for male and female this website animals and time points were combined for each experimental group (n = 24) for these results. Experimental groups analyzed were the following: control animals fed normal chow and uninfected (Control; C); animals fed normal chow and infected with non-viable MAP cells, (Killed-MAP; K-MAP); animals fed normal chow and infected with viable

MAP cells (Live-MAP; L-MAP); animals fed viable probiotics in chow and uninfected (Live NP-51; L-NP-51); animals fed viable probiotics in chow and infected with non- viable MAP cells (K-MAP + L-NP-51); animals fed viable probiotics in chow and infected with viable MAP cells (L-MAP + L-NP-51). Data analysis methods are further described in the data analysis section. Figure 4 Tissue cytokine transcript abundance relative to controls and associated with chronic MAP infection. Data for male and female animals, time points, check details and tissues (small/large intestine and liver) were combined for each experimental

group (n = 24). Experimental groups analyzed were the following: animal fed normal chow and uninfected (Control; C); animals fed normal chow and infected with non-viable MAP cells, (Killed-MAP; K-MAP); animals fed normal chow and infected with viable MAP cells (Live-MAP; L-MAP); animals fed viable probiotics in chow and uninfected (Live NP-51; L-NP-51); animals fed viable probiotics in chow and infected with non-viable MAP cells ( K-MAP + L-NP-51); Phosphatidylinositol diacylglycerol-lyase animals fed viable probiotics in chow and infected with viable MAP cells (L-MAP + L-NP-51). Data analysis methods are further described in the data analysis section. With viable MAP (L-MAP) infection, the immune response produced is characteristic of Th1 cell responses to intracellular pathogens with the production of IFN-Υ, IL-6, IL-12 (as described in Figure 3) [1, 2, 8]. In animals that were infected with viable MAP and fed viable probiotics (L- MAP + L-NP-51) – there is IFN-Υ production likely due to intracellular infection by MAP but this response is weaker compared to animals infected only with viable MAP, (see Figure 3). Equally, IL-12 levels are elevated but with NP-51 consumption we again observe a decrease in IL-6 circulation and an increase in pro-inflammatory cytokine- TNF-α.

01) and HLHK9∆ureA/arcA1/arcA2 (p < 0.01) (Figure  3C), and the reduction trend became more pronounced after 3 and 5 h incubation (Figure  3D). At pH 2 and 3, the survival counts of HLHK9∆ureA started to decrease (P <0.05), whereas there were dramatic decreases in the survival counts of HLHK9∆arcA1/arcA2 (p < 0.001) and triple knockout

mutant HLHK9∆ureA/arcA1/arcA2 strains, which were almost completely killed (p < 0.001) (Figure  3C). These showed that the ADI pathway of L. hongkongensis played a more important role than the urease in resisting acidic environments. Intracellular survival in J774 macrophages and mRNA this website Expression level analyses Survival PF-6463922 of wild type L. hongkongensis HLHK9, HLHK9∆ureA, HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 in J774 macrophages were shown in Figure  4A. Survival of HLHK9∆ureA/arcA1/arcA2 and HLHK9∆arcA1/arcA2 in macrophages were markedly decreased (p < 0.001 and p < 0.01 respectively) but that of HLHK9∆ureA was slightly decreased (p < 0.05), compared to wild type L. hongkongensis HLHK9. The decrease of survival was more prominent in HLHK9∆ureA/arcA1/arcA2, compared to HLHK9∆arcA1/arcA2 (p < 0.05) and HLHK9∆ureA (p < 0.01); and in HLHK9∆arcA1/arcA2,

compared to HLHK9∆ureA (p < 0.05). Given the above results, we further investigated the expression level of ADI genes (arcA1 and arcA2) and ureA gene of wild type L. hongkongensis HLHK9 survived in macrophages using real-time quantitative RT-PCR assay. At 8 h post infection, the mRNA levels of arcA1, arcA2 and ureA genes were markedly increased BAY 11-7082 research buy compared to those at 2 h post infection (p < 0.05, p < 0.01 Avelestat (AZD9668) and p < 0.05 respectively) (Figure  4B). Figure 4 Intracellular survival assays in J774 macrophages. A, Recovery rates of wild type L. hongkongensis HLHK9, HLHK9∆ureA,

HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 in J774 macrophages. B, Expression level of ADI genes (arcA1 and arcA2) and ureA gene of HLHK9 in macrophages. Error bars represent means ± SEM of three independent experiments. An asterisk indicates a significant difference (*, p < 0.05; **, p < 0.01; ***, p < 0.001). Survival of L. hongkongensis strains in BALB/c mice To further investigate the role of urease and ADI pathway in acid tolerance of L. hongkongensis, we compared the survival ability of HLHK9, mutant strains HLHK9∆ureA, HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 after transit through the stomach of mice. Using this mouse model, HLHK9∆ureA exhibited similar survival abilities as HLHK9 (Figure  5). In contrast, the viable counts of HLHK9∆arcA1/arcA2 and HLHK9∆ureA/arcA1/arcA2 were reduced by 1.2-log and 1.3-log respectively, compared to that of HLHK9 (p < 0.01) (Figure  5). This also indicated that the ADI pathway played a more significant role than urease in the survival of L.

Spa-typing

with the standard primer sets (1095 F/1517R) demonstrated that AE only ever carried one strain, which was type t230 at most time points, the spa-type t008 on one occasion and one non-typeable strain. Re-typing the same DNA extractions with our alternative novel primers (spaT3-F/1517R) showed that all samples had mixed sequence traces, apart from the formerly non-typeable strain that had deletion E associated with spa-type t012. Therefore, 12 single colonies Akt inhibitor were isolated for each sample and re-typed with alternative primers. This identified five spa-types carried by AE at various time points, and mixed strain colonization by two-three spa-types on four occasions, including two strains with deletion E. We were unable to resolve all samples by typing 12 individual colonies, even though they showed presence of mixed sequence traces (time points 4, 10, 12 and 14), which could STI571 be explained by a low frequency of one of the colonizing strains. Table 3 Spa -typing of S. aureus strains from a single individual AE with two sets of primers: standard primers 1095 F/1517R and novel primers spaT3-F/1517R Time points, months DNA prep (mixed boilate) 12 single colony picks2   1095 F/1517R spaT3-F/1517R spaT3-F/1517R AE-0 t230 MST1 t230/t012 AE-1 Selleckchem SGC-CBP30 non-typable t012 t012 AE-2 t230 MST t230/t012 AE-4 t230 MST t230 AE-6 t230 MST t230/t528 AE-8 t008 MST t008/t012/t571 AE-10 t230 MST t230 AE-12 t230 MST t230 AE-14 t230 MST t230

1mixed sequence traces; 2 spa-types in bold have delE and could not be typed with standard primers; spa-repeats: t230: 08-16-02-16-34. t571: 08-16-02-25-02-25-34-25. t008: 11-19-12-21-17-34-24-34-22-25. t012: 15-12-16-02-16-02-25-17-24-24. t528: 04. The limitations of the conventional spa-typing protocol make it impossible to identify and type S. aureus strains with rearrangements in the spa-gene in individuals with multiple strain colonization.

The staged spa-typing protocol allows us to resolve cases of mixed strain colonization with deletions in one or more strains. Even 12 single colony picks could not always identify the presence of low-frequency strains with deletions, 4-Aminobutyrate aminotransferase illustrating the even greater challenge of estimating the proportion of non-typeable strains within mixed colonization. Thus diversity in colonizing and infecting strains is inevitably underestimated. Inpatients’ strains can acquire deletions in the spa-gene We also found that S. aureus strains can acquire deletions in the spa-gene during inpatients’ hospital admission. Such acquisition of deletions was never observed for longitudinal carriage strains from individuals in the community, with those deletions observed being present from the first time the strain carrying the deletion was identified (Additional file 1: Table S1). Among six hospital patients with deletions that affect spa-typing, three individuals (BA, BB and BF) already carried the strain with the deletion when they were admitted.

In the present study, the eGFR slope was less in the older group than younger group (Table 3), but the difference was not statistically significant (P = 0.154). In addition, there was no significant relationship between age and eGFR slope (Fig. 2a). Both the present

and CRISP AICAR price study [3] suggest that the eGFR slope is not significantly affected by age, at least after adolescence. The MDRD equation for estimating GFR is widely used [8–10] but its accuracy was recently reported to be 83% in ADPKD patients [21]. Renal Capmatinib solubility dmso function changes are qualitatively reflected by the 1/Cr slope in individual subjects, because individual body muscle volume and hydration status are relatively stable in most patients, at least for relatively short periods of a few years. In the present study, the 1/Cr slope was analyzed in addition to the eGFR

slope and the results were qualitatively similar in both analyses (Tables 2, 3; Figs. 3, 4). In 5 of 36 patients followed for more than 5 years, renal disease progression accelerated during observation (Fig. 4). This acceleration did not seem to be related to age or eGFR level, but presumably to individually different causes, including infection, hematuria, obstruction by urolithiasis or other events. If the acceleration of renal disease progression is due to the end of the renal compensation mechanism, the terminal points of the compensation mechanism might be heterogeneous among ADPKD patients. In relatively younger adult (29.9 ± 11.4 years) patients whose renal function was retained AG-120 chemical structure (CKD

stage 1 in Table 2), the eGFR slope was already negative. In the majority of patients with initially measured eGFR >90 ml/min/1.73 m2, the eGFR slope was negative, as shown in Fig. 2b. These results suggest that the renal compensation mechanism might terminate in the second decade of life in most patients with ADPKD. A recent study which examined the detailed renal functions Amisulpride of young ADPKD patients showed abnormal kidney function even in the younger generation [4]. In a quartile of the younger age group (27 ± 5 years) in that study, GFR decreased but was statistically not different from that of the normal healthy controls. Even in these younger age group patients, effective renal plasma flow sharply decreased. Patients with CKD stage 1 (Table 2) in the present study correspond to quartile 1 group patients in that study [4], because age (29.9 ± 11.4 vs 27 ± 5 years) and eGFR (113.8 ± 25.9 ml/min/1.73 m2) in the present study and GFR measured by iothalamate clearance (117 ± 32 ml/min) were not statistically different. The present study shows a negative eGFR slope and the study [4] showed decreased renal plasma flow in similar younger adult patients who maintained apparently normal GFR. Initially measured eGFR in relation to age in hypertensive patients was lower than that in normotensive patients, and the present results indicated that differences in eGFR between the two groups had already occurred before age 36 (Fig. 5a; Table 4).

Our findings indicate that about half of the typical and atypical EPEC strains and Talazoparib price serotypes are closely related to EHEC regarding these virulence attributes (Table 2). The presence of OI-122 encoded genes, followed by OI-71 were most significant for the assignment of EPEC to the “”EHEC-related”" Cluster 1 confirming data from our previous study performed on a different collection of strains [17]. The OI-57 encoded

genes nleG5-2 and nleG6-2, as well as the espK gene were not as strongly associated with Cluster 1, as the OI-122 and OI-71 genes. Recently, the OI-57 associated genes adfO and ckf were reported to be present in 30 (71%) of 42 investigated EPEC strains Lonafarnib research buy but a high variability of OI-57 associated orfs in EPEC strains was observed [28]. This could explain the results of our study, where the OI-57 associated nleG5-2 gene was found infrequently in all EPEC, whereas the nleG6-2 gene was frequent in atypical EPEC (45.5%) but rarely found in typical EPEC (12.3%) (Table 1). Further work is needed to define the genes of OI-57 that are most suitable for the molecular risk assessment of EHEC and EPEC strains. In our study, EHEC-plasmids were associated with EHEC, STEC and Sapitinib cell line atypical EPEC, but not with typical EPEC strains. EHEC-plasmids are frequently harboured by classical EHEC

but also by many LEE-negative aminophylline STEC strains [32–34]. Correspondingly, EHEC-plasmid encoded genes ehxA, etpD, katP and espP had only a small influence on Cluster 1 formation, confirming results of previous studies [16, 17]. In this study, EHEC-plasmid genes were significantly more associated with atypical EPEC Cluster 1 than with Cluster 2 strains. The high proportion of EHEC-plasmid

positives among Cluster 1 strains suggests that many of these may have derived from EHEC by losing stx-genes. A loss of stx-genes was reported to occur frequently in classical EHEC strains [23, 26]. EHEC-plasmid genes were found in 23/29 (79.3%) of atypical EPEC Cluster 1 strains belonging to EHEC related serotypes O26:H11, O103:H2, O145:H28 and O157:H7 (data not shown). These 30 EHEC-like strains showed the same virulence characteristics (presence of OI-122 genes) as their homologous EHEC strains. In addition to this, there are epidemiological findings pointing to a closer relationship between “”Cluster 1″” atypical EPEC and EHEC strains. Significantly (p < 0.05) more typable (78/120 = 65.0%) Cluster 1 strains than Cluster 2 strains belonged to serotypes (18/40 = 45.0%) that are associated with the production of Shiga toxins (38). Only 26.6% (24/90) of the atypical EPEC strains of Cluster 2 showed O:H types (10/46 = 21.7) previously associated with Stx-production. Typical EPEC were also found to split into Cluster 1 and Cluster 2 strains.