Stereotactic radiosurgery and radiotherapy for resected brain metastases: current pattern of care in the Radiosurgery and Stereotactic Radiotherapy Working Group of the German Association for Radiation Oncology (DEGRO).

PURPOSE: Preoperative stereotactic radiosurgery (SRS) of brain metastases may achieve similar local control and better leptomeningeal control rates than postoperative fractionated stereotactic radiotherapy (FSRT) in patients treated with elective metastasectomy. To plan a multicentre trial of preoperative SRS compared with postoperative FSRT, a survey of experts was conducted to determine current practice. METHODS: A survey with 15 questions was distributed to the DEGRO Radiosurgery and Stereotactic Radiotherapy Working Group. Participants were asked under what circumstances they offered SRS, FSRT, partial and/or whole brain radiotherapy before or after resection of a brain metastasis, as well as the feasibility of preoperative stereotactic radiosurgery and neurosurgical resection within 6 days. RESULTS: Of 25 participants from 24 centres, 22 completed 100% of the questions. 24 respondents were radiation oncologists and 1 was a neurosurgeon. All 24 centres have one or more dedicated radiosurgery platform and all offer postoperative FSRT. Preoperative SRS is offered by 4/24 (16.7%) centres, and 9/24 (37.5%) sometimes recommend single-fraction postoperative SRS. Partial brain irradiation is offered by 8/24 (33.3%) centres and 12/24 (50%) occasionally recommend whole-brain irradiation. Two centres are participating in clinical trials of preoperative SRS. SRS techniques and fractionation varied between centres. CONCLUSION: All responding centres currently offer postoperative FSRT after brain metastasectomy. Approximately one third offer single-fraction postoperative SRS and four already perform preoperative SRS. With regard to potential co-investigators, 18 were identified for the PREOP­2 multicentre trial, which will randomise between preoperative SRS and postoperative FSRT.

Randomized feasibility trial of replacing or discarding the nail plate after nail-bed repair in children.

BACKGROUND: Nail-bed injuries are the most common hand injury in children. Surgical dogma is to replace the nail plate after repairing the nail bed. Recent evidence suggests this might increase infection rates and returns to clinic. The aim of this feasibility trial was to inform the design and conduct of a definitive trial comparing replacing or discarding the nail plate after nail-bed repair. METHODS: This study recruited participants from four hand units in the UK between April and July 2015. Participants were children under the age of 16 years with a nail-bed injury requiring surgery. They were randomized to either having the nail plate replaced or discarded after nail-bed repair. The follow-up method was also allocated randomly (postal versus clinic). Information was collected on complications at 2 weeks and 30 days, and on nail-plate appearance at 4 months using the Zook classification. Two possible approaches to follow-up were also piloted and compared. RESULTS: During the recruitment phase, there were 156 potentially eligible children. Sixty were randomized in just over 3 months using remote web-based allocation. By 2 weeks, there were two infections, both in children with replaced nail plates. The nail-replaced group also experienced more complications. There was no evidence of a difference in return rates between postal and clinic follow-up. CONCLUSION: Recruitment was rapid and nail-bed repair appeared to have low complication and infection rates in this pilot trial. The findings have led to revision of the definitive trial protocol, including the mode and timing of follow-up, and modification of the Zook classification.

What comes first? The dynamics of cerebral oxygenation and blood flow in response to changes in arterial pressure and intracranial pressure after head injury.

BACKGROUND: Brain tissue partial oxygen pressure (Pbt(O(2))) and near-infrared spectroscopy (NIRS) are novel methods to evaluate cerebral oxygenation. We studied the response patterns of Pbt(O(2)), NIRS, and cerebral blood flow velocity (CBFV) to changes in arterial pressure (AP) and intracranial pressure (ICP). METHODS: Digital recordings of multimodal brain monitoring from 42 head-injured patients were retrospectively analysed. Response latencies and patterns of Pbt(O(2)), NIRS-derived parameters [tissue oxygenation index (TOI) and total haemoglobin index (THI)], and CBFV reactions to fluctuations of AP and ICP were studied. RESULTS: One hundred and twenty-one events were identified. In reaction to alterations of AP, ICP reacted first [4.3 s; inter-quartile range (IQR) -4.9 to 22.0 s, followed by NIRS-derived parameters and CBFV (10.9 s; IQR: -5.9 to 39.6 s, 12.1 s; IQR: -3.0 to 49.1 s, 14.7 s; IQR: -8.8 to 52.3 s for THI, CBFV, and TOI, respectively), with Pbt(O(2)) reacting last (39.6 s; IQR: 16.4 to 66.0 s). The differences in reaction time between NIRS parameters and Pbt(O(2)) were significant (P<0.001). Similarly when reactions to ICP changes were analysed, NIRS parameters preceded Pbt(O(2)) (7.1 s; IQR: -8.8 to 195.0 s, 18.1 s; IQR: -20.6 to 80.7 s, 22.9 s; IQR: 11.0 to 53.0 s for THI, TOI, and Pbt(O(2)), respectively). Two main patterns of responses to AP changes were identified. With preserved cerebrovascular reactivity, TOI and Pbt(O(2)) followed the direction of AP. With impaired cerebrovascular reactivity, TOI and Pbt(O(2)) decreased while AP and ICP increased. In 77% of events, the direction of TOI changes was concordant with Pbt(O(2)). CONCLUSIONS: NIRS and transcranial Doppler signals reacted first to AP and ICP changes. The reaction of Pbt(O(2)) is delayed. The results imply that the analysed modalities monitor different stages of cerebral oxygenation.

Cerebral arterial compliance in patients with internal carotid artery disease.

BACKGROUND: A decrease in arterial compliance of the internal carotid artery has been associated with an increased risk in ipsilateral ischaemic stroke. However, so far, no technique has been validated to monitor the compliance of intracerebral arteries (Ca) in patients with carotid artery disease. In this study, we sought to monitor Ca in patients with unilateral symptomatic disease and to determine its variations during changes in PaCO(2). METHODS: We studied 18 patients with unilateral symptomatic internal carotid artery stenosis >50% or occlusion. Patients underwent monitoring of arterial blood pressure (ABP) and middle cerebral artery cerebral blood flow velocities (CBFV) during baseline, hyperventilation and 5%CO(2) inhalation. Ca was calculated from pulsatile amplitudes of ABP and Cerebral arterial blood volume, extracted from the CBFV waveform using a new mathematical model. RESULTS: At baseline, the decrease in Ca on the diseased side was correlated with the degree of stenosis (r = -0.35; P = 0.01). During hypocapnia, Ca was lower compared to baseline on the normal side (P = 0.004) and on the diseased side (P = 0.04). Ca reactivity, reflecting the changes in Ca per changes in 1 mmHg PaCO(2), was lower on the diseased side between baseline and hypocapnia (3.4 vs. 2.6%; P = 0.04). During hypercapnia, no changes in Ca on the diseased (P = 0.8) nor on the normal sides (P = 0.2) were observed. CONCLUSIONS: The decrease in cerebral arterial compliance the side of stenosis/occlusion was correlated with the severity of the internal carotid artery disease. Further studies are needed to determine whether Ca may improve the prediction of ischaemic events in symptomatic and asymptomatic patients.

[Antimicrobial resistance of Staphylococcus aureus and coagulase negative staphylococci isolated from mastitis milk samples from sheep and goats]. / Antibiotikaresistenz von Staphylococcus aureus und Koagulase-negativen Staphylokokken isoliert aus Mastitismilchproben von Schafen und Ziegen.

Staphylococcus aureus and coagulase negative staphylococci (CNS) were isolated from ovine and caprine mastitis milk samples originating from more than 40 Swiss farms. CNS dominated as causal microorganisms of mastitis in small ruminants. By restriction fragment length polymorphism (RFLP) analysis of the groEL gene and sequencing of 16S rDNA, various CNS species were identified, albeit certain of them predominated. For susceptibility testing of mastitis pathogens to selected antibiotics, minimal inhibitory concentrations were determined. Of the 67 S. aureus and 208 CNS strains, 31.3 % and 8.2 % were resistant to penicillin, 29.9 % and 1.0 % to ampicillin, 1.5 % and 10.6 % to erythromycin, and 3.0 % and 7.7 % to tetracycline, respectively. Moreover, 10 CNS strains (4.8 %) were resistant to oxacillin and one CNS strain to sulfamethoxazole/trimethoprim. The results obtained describe for the first time the resistance situation of mastitis pathogens from sheep and goats in Switzerland. However, accompanying and preventing measures are also of importance in mastitis control of small ruminants.

St Andrew's COVID-19 surgery safety study: hand trauma.

INTRODUCTION: Adaptation is vital to ensure successful healthcare recovery during the COVID-19 pandemic. Hand trauma represents the most common acute emergency department presentation internationally. This study prospectively evaluates the COVID-19 related patient risk, when undergoing management within one of the largest specialist tertiary referral centres in Europe, which rapidly implemented national COVID-19 safety guidelines. MATERIALS AND METHODS: A prospective cohort study was undertaken in all patients referred to the integrated hand trauma service, during the UK COVID-19 pandemic peak (April-May 2020); all were evaluated for 30-day COVID-19 related death. Random selection was undertaken for patients with hand trauma who either underwent non-operative (control group) or operative (surgery group) management; these groups were prospectively followed-up within a controlled cohort study design and telephoned at 30 days following first intervention (control group) or postoperatively (surgery group). RESULTS: Of 731 referred patients (566 operations), there were no COVID-19 related deaths. Both groups were matched for sex, age, ethnicity, body mass index, comorbidities, smoking, preoperative/first assessment COVID-19 symptoms, pre- and postoperative/first assessment isolation and positive COVID-19 contact (p > 0.050). There were no differences in high service satisfaction (10/10 compared with 10/10; p = 0.067) and treatment outcome (10/10 compared with 10/10; p = 0.961) scores, postoperative/first assessment symptoms (1%, 1/100 compared with 0.8%, 2/250; p = 1.000) or proportion of positive tests (7.1%, 1/14 compared with 2.2%, 2/92; p = 0.349), between the control (n = 100) and surgery (n = 250) groups. CONCLUSION: These data support continued and safe service provision and no increased risk to patients who require surgical management. Such findings are vital for healthcare providers when considering service adaptations to reinstate patient treatment.

Characteristics of shiga toxin-producing Escherichia coli isolated from Swiss raw milk cheese within a 3-year monitoring program.

Food is an important vehicle for transmission of Shiga toxin-producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx(1) was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx(2) group, mainly stx(2) and stx(2vh-a/b). Production of Stx(2) and Stx(2vh-a/b) subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

Prevalence and characteristics of meticillin-resistant Staphylococcus aureus in humans in contact with farm animals, in livestock, and in food of animal origin, Switzerland, 2009.

A total of 2,662 samples, collected from March to September 2009 in Switzerland, were tested for the presence of meticillin-resistant Staphylococcus aureus (MRSA). The collection comprised nasal swabs from 148 pig farmers, 133 veterinarians, 179 slaughterhouse employees, 800 pigs, 300 calves, 400 cattle, 100 pooled neck skin swabs from chicken carcasses, and 460 food samples of animal origin. Moreover, 142 S. aureus strains, isolated from bovine mastitis milk, were included in the study. Twenty samples (< 1%; four veterinarians, 10 pigs, three calves, one young bull, and two mastitis milk samples) tested positive for MRSA. Genotyping of the MRSA strains was performed by multilocus sequence typing, spa- and SCCmec-typing, and revealed ST398 (n=18), ST8 (n=1), ST 1 (n=1), spa types t011 (n=7), t034 (n=11), t064 (n=1), t127 (n=1), and SCCmec types IV (n=4) and V (n=16). The 20 MRSA strains were subjected to antibiotic susceptibility testing and pulsed-field gel electrophoresis using the restriction enzyme EagI. Supplementary PCR reactions were performed to investigate the presence of Panton-Valentine leukocidin and staphylococcal enterotoxins A to D.

[Raw milk-associated Staphylococcus aureus intoxication in children]. / Rohmilch-assoziierte Staphylococcus aureus Intoxikation bei Kindern.

Four hours after the consumption of raw goat milk, three Swiss children came down with emesis and diarrhea in July 2008. First investigations showed that the milk originated from a goat suffering from clinical mastitis (Staphylococcus aureus). In the milk sample from the untreated left udder, Staphylococcus aureus counts reached 5.0 x 10(7) CFU ml(-1). By PCR, the gene for the staphylococcal enterotoxin D was found in isolated strains. The consumption of raw milk is rarely associated with Staphylococcus aureus intoxications. Due to the flora naturally present in raw milk, Staphylococcus aureus normally cannot multiply sufficiently. However, in the present case, high Staphylococcus aureus counts were already present in the milk due to the mastitis of the goat. This amount sufficed to cause a Staphylococcus aureus intoxication in the children.

Antimicrobial resistance in Escherichia coli strains isolated from Swiss weaned pigs and sows.

Based on Directive (EC) No 99/2003, monitoring programs on the development of antimicrobial resistance in bacteria from livestock are implemented in many European countries. The aim of the present study was (i) to establish comprehensive baseline data on the antimicrobial resistance situation in Escherichia coli isolates obtained from healthy pigs (pooled fecal samples) originating from 60 Swiss pig-breeding farms, and (ii) to analyze differences in the resistance frequency between Escherichia coli isolates from weaned pigs and sows. Susceptibility testing (disc diffusion method) was performed on 429 isolates from weaned pigs and 431 isolates from sows. Overall, 17.7% of the isolates from weaned pigs and 22.5% of the Escherichia coli isolates from sows were susceptible to all antibiotics tested. Low resistance prevalence was found for amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefquinome, ciprofloxacin, colistin, florfenicol, and gentamicin. The most frequently found resistances were against streptomycin (60.6% of the isolates from weaners and 64.3% of the isolates from sows), sulfonamide (51.5% and 26.9%), tetracycline (35.2% and 22.0%), and trimethoprim (27.5% and 11.1%). With exception of colistin, most resistances were found for those antibiotics commonly used on the farms. Except for ciprofloxacin and streptomycin, isolates from weaned pigs showed higher resistance prevalence than those from sows. This difference was significant for cefquinome, florfenicol, sulfonamide, tetracycline, and trimethoprim (p<0.05).

Shedding of food-borne pathogens and microbiological carcass contamination in rabbits at slaughter.

To obtain microbiological data from rabbits at slaughter, 500 fecal samples and 500 carcasses samples were examined. All samples tested negative for Listeria and Salmonella. Campylobacter were detected in two fecal samples. Of the 500 fecal samples, 45.8% tested positive for eae (intimin), 1.2% for stx (Shiga toxin), and 1.8% for both eae and stx. By colony hybridization, 56 eae positive Escherichia coli strains were isolated. Among them, 27 strains (48.2%) were of the serotypes O178:H7 and O153:H7, whereas 15 strains (26.8%) belonged to a serogroup that has not yet been described (O(CB10681):H7). All strains possessed intimin beta1 and the translocated intimin receptor (tir) capable of being tyrosine phosphorylated. None of the strains harbored the genes for Shiga toxins, EAST1 (astA), bundlin (bfpA), or the EAF plasmid. Slaughter rabbits therefore constitute a reservoir for certain atypical enteropathogenic Escherichia coli. On rabbit carcasses, average total bacterial counts accounted for 3.3 log CFU cm(-2). Enterobacteriaceae and coagulase positive staphylococci (CPS) were detected on 118 (23.6%) and 153 (30.6%) carcasses, respectively. Enterobacteriaceae and CPS counts of positive samples were mainly <1.5 log CFU cm(-2). Among 153 selected CPS isolates, 98.7% were identified as Staphylococcus aureus. None of the 151 isolated strains harbored the gene for methicillin resistance (mecA). Genes for staphylococcal enterotoxins (SE) were detected in 102 strains. The combinations of seg and sei (53 strains) and sed, seg, sei, and sej (27 strains) dominated.

Electrolyzed water and its application in the food industry.

Electrolyzed water (EW) is gaining popularity as a sanitizer in the food industries of many countries. By electrolysis, a dilute sodium chloride solution dissociates into acidic electrolyzed water (AEW), which has a pH of 2 to 3, an oxidation-reduction potential of >1,100 mV, and an active chlorine content of 10 to 90 ppm, and basic electrolyzed water (BEW), which has a pH of 10 to 13 and an oxidation-reduction potential of -800 to -900 mV. Vegetative cells of various bacteria in suspension were generally reduced by > 6.0 log CFU/ml when AEW was used. However, AEW is a less effective bactericide on utensils, surfaces, and food products because of factors such as surface type and the presence of organic matter. Reductions of bacteria on surfaces and utensils or vegetables and fruits mainly ranged from about 2.0 to 6.0 or 1.0 to 3.5 orders of magnitude, respectively. Higher reductions were obtained for tomatoes. For chicken carcasses, pork, and fish, reductions ranged from about 0.8 to 3.0, 1.0 to 1.8, and 0.4 to 2.8 orders of magnitude, respectively. Considerable reductions were achieved with AEW on eggs. On some food commodities, treatment with BEW followed by AEW produced higher reductions than did treatment with AEW only. EW technology deserves consideration when discussing industrial sanitization of equipment and decontamination of food products. Nevertheless, decontamination treatments for food products always should be considered part of an integral food safety system. Such treatments cannot replace strict adherence to good manufacturing and hygiene practices.

Microbiological contamination of pig and cattle carcasses in different small-scale Swiss abattoirs.

A total of 750 pig carcasses and 535 cattle carcasses from 17 small-scale abattoirs were sampled by excision at four sites (pig: neck, belly, back, ham; cattle: neck, brisket, flank, rump). Samples were examined for total viable counts (TVC) and Enterobacteriaceae. Mean TVCs ranged from 2.4 to 4.2 log(10)CFUcm(-2) on pig carcasses and from 2.7 to 3.8 log(10)CFUcm(-2) on cattle carcasses. With regard to EU Regulation (EC) No 2073/2005, TVCs were mainly considered satisfactory (pig: 81.3%; cattle: 71.4%). Amongst sites, the back (pigs) and neck (cattle) tended to yield higher TVCs. Enterobacteriaceae were detected in low counts on 23.9% of pig carcasses and 21.7% of cattle carcasses. Amongst abattoirs, Enterobacteriaceae prevalence on pig and cattle carcasses ranged from 2.0% to 56.0% and from 0.0% to 55.0%, respectively. Consequently, criteria of the EU Regulation proved to be a suitable tool for the appraisal of microbiological results (TVCs) from pig and cattle carcasses from small-scale abattoirs. Because the occurrence of Enterobacteriaceae on carcasses was too infrequent to ensure log normality, frequencies should be compared for these organisms.

Characteristics of Staphylococcus hyicus strains isolated from pig carcasses in two different slaughterhouses.

In a previous study, we showed that coagulase positive staphylococci, which are often used as indicators for Staphylococcus aureus, are frequently found on pig carcasses. Further characterization of the strains identified only a minor part as S. aureus. Selected non-S. aureus strains were all identified as Staphylococcus hyicus, However, two studies described in this species strains that produce staphylococcal enterotoxins. The aim of the present study was to further characterize such coagulase positive S. hyicus strains isolated from pig carcasses and to assess the results for their food safety relevance. A total of 189 strains from two abattoirs were characterized. Phenotypically, 98.9% showed non-pigmented colonies, 99.5% no haemolysis and 67.7% were egg yolk-positive. DNase activity was found in all but one isolate. Only five of the 189 strains were resistant to the antimicrobials tested. One strain harboured the mecA gene. Exfoliative toxin genes were detected in 31 (16.4%), S. aureus enterotoxin genes in none of the strains. The PFGE genotyping results show only a limited number of clusters. Cluster I included more than 50% of the strains. The fact that similar or closely related PFGE patterns of S. hyicus can be found on carcasses after bleeding in both abattoirs indicates the occurrence of widespread strains in the Swiss pig population. Moreover, the genotyping results revealed a remarkable homogeneity in S. hyicus strains isolated from different process stages in abattoir B, which could indicate a recontamination problem with persisting strains.

Non-tuberculous Mycobacteria isolated from lymph nodes and faecal samples of healthy slaughtered cattle and the abattoir environment.

Infections caused by non-tuberculous mycobacteria (NTM) are reported as emerging disease in many countries worldwide. The occurrence of NTM in different hosts and their implication as obligate or opportunistic pathogen remain largely unclear. Lymph nodes and faecal samples of clinically healthy Swiss cattle at slaughter were analysed for the presence of NTM. Based on the examined lymph nodes, NTM were detected in 20% of 108 cattle originating from different premises. The 22 isolates belonged to five different species of Mycobacteria (M. avium subsp. hominissuis, M. kansasii, M. persicum, "M. lymphaticum" and M. europaeum). M. avium subsp. hominissuis (63%) and M. kansasii (18%) thereby predominated and were found in lymph nodes with and without macroscopic changes. Moreover, M. persicum found in two cattle has recently been described as a human pathogen and is closely related to M. kansasii. Amongst cattle with lymph nodes positive for mycobacteria, viable NTM were occasionally also detected in bovine faeces. However, the isolated NTM species from lymph nodes and respective faecal samples (M. hassiacum, M. phlei and M. vaccae) did not coincide. Moreover, NTM species identified amongst isolates from the slaughterhouse environment clearly differed from those from lymph nodes and faecal samples, excluding cross-contamination of the tissue specimens through the environment or laboratory processing. Assuming that some NTM interfere with the detection of bovine tuberculosis (bTB), the present findings in healthy animals emphasize the need of more specific diagnostic tools for bTB eradication programs.

Phenotypic and genotypic traits of Staphylococcus aureus strains isolated from pig carcasses.

A total of 142 S. aureus strains isolated from pig carcasses from abattoirs A (n=98) and B (n=44) were characterized by phenotypic and genotypic traits. Phenotypically, 96% showed yellow-pigmented colonies, 63% beta/delta hemolysis, 85% were egg yolk-positive and 99% were positive for clumping factor/protein A. Only 25% of the strains were resistant to the antimicrobials tested (abattoir A: 19%; abattoir B: 39%), especially to penicillin and ampicillin. None of the strains harbored the mecA gene, which is conserved in methicillin-resistant S. aureus. The biofilm associated genes icaA, icaD and bap were present in 100%, 100% and 0% of the strains. Genes for staphylococcal enterotoxin (SE) were detected in 51% (abattoir A) and 14% of the strains (abattoir B). Among strains harboring SE genes (n=56), 63%, 31%, 4% and 2% tested positive for seg/sei, seg, sei and sec, respectively. The amplification of the 3' end of the coagulase gene (coa) yielded amplicons of 400, 436, 602, 682 or 776bp. Coa restriction profile (CRP) analysis using HaeIII resulted in seven patterns (a-d, e1-e3). CRP (c) was detected most frequently at both abattoirs, whereas CRP (a) was restricted to abattoir A and CRP (e3) to abattoir B. In the slaughter process (abattoir B), (i) two CRPs (b and d) were only found before dehairing/singeing, and (ii) four CRPs (c, e1-e3) were identified throughout the process. The genotyping revealed a remarkable homogeneity in S. aureus strains from the two different abattoirs and the slaughter process stages. These results may be explained by the distribution of a limited number of S. aureus genotypes in the pig population. Moreover, as the predominant CRPs (c, e1-e3) persisted throughout the slaughter process in abattoir B, it may be hypothesized that these types are characterized by colonization advantages.

Virulence profiles of Shiga toxin 2e-producing Escherichia coli isolated from healthy pig at slaughter.

Recently, virulence patterns of Stx2e-producing Escherichia coli from pigs with edema disease and from humans were compared and strains from diseased pigs were reported to be unlikely human pathogens [Sonntag, A.K., Bielaszewska, M., Mellmann, A., Dierksen, N., Schierack, P., Wieler, L.H., Schmidt, M.A., Karch, H., 2005. Shiga toxin 2e-producing Escherichia coli isolates from humans and pigs differ in their virulence profiles and interactions with intestinal epithelial cells. Appl. Environ. Microbiol. 71, 8855-8863]. In the present study, 31 Shiga toxin-producing E. coli (STEC) strains harboring stx2e, which were previously isolated out of fecal samples from healthy pigs at slaughter [Kaufmann, M., Zweifel, C., Blanco, M., Blanco, J.E., Blanco, J., Beutin, L., Stephan, R., 2006. Escherichia coli O157 and non-O157 Shiga toxin-producing Escherichia coli in fecal samples of finished pigs at slaughter in Switzerland. J. Food Prot. 69, 260-266], were characterized by phenotypic and genotypic traits. Nine of the thirty-one sorbitol-positive non-O157 STEC (stx2e) isolated from healthy pigs belonged to serotypes found in STEC isolated from humans, including two serotypes (O9:H-, O26:H-) reported in association with hemolytic-uremic syndrome. Otherwise, the serotypes were different from those isolated from cases of edema disease in pigs. The eae (intimin) gene, which is strongly correlated with severe human disease, was not detected. Moreover, all strains were lacking the genes for enterohemolysin (ehxA), porcine A/E associated protein (paa), STEC autoagglutinating adhesin (saa) and the serin protease EspI (espI). Nine strains tested positive for astA (EAST1), one O141:H17 strain for fedA (F18 fimbrial adhesin) and one O159:H- strain for terF (tellurite resistance). Similar to the Stx2e-producing E. coli isolated from humans, which are mainly lacking further virulence factors, genes of an iron uptake system on the high-pathogenicity island (irp2, fyuA) were detected in three ONT:H10 and ONT:H19 strains from healthy pigs. Consequently, although the isolated strains are unlikely to be associated with severe human diseases, healthy pigs cannot be excluded as a potential source of human infection with Stx2e-producing STEC.

Microbiological contamination of pig carcasses at different stages of slaughter in two European Union-approved abattoirs.

At sequential steps of slaughter (scalding, dehairing, singeing, polishing, trimming, washing, and chilling), 200 pig carcasses from two abattoirs were examined for total viable bacteria count (TVC) and the presence of Enterobacteriaceae and coagulase-positive Staphylococcus (CPS) by the wet-dry double-swab technique at the neck, belly, back, and ham. Before scalding, mean TVCs ranged from 5.0 to 6.0 log CFU cm(-2), and Enterobacteriaceae and CPS were detected on all carcasses. At abattoir A, mean TVCs and the percentage of Enterobacteriaceae-positive carcasses were reduced (P < 0.05) after scalding (1.9 log CFU cm(-2) and 12%, respectively), singeing (1.9 log CFU cm(-2) and 66%, respectively), and blast chilling (2.3 log CFU cm(-2) and 17%, respectively) and increased (P < 0.05) after dehairing (3.4 log CFU cm(-2) and 100%, respectively) and polishing (2.9 log CFU cm(-2)). The proportion of CPS-positive samples decreased to < or = 10% after scalding and remained at this level. At abattoir B, mean TVCs and the percentages of Enterobacteriaceae- and CPS-positive carcasses were reduced (P < 0.05) after scalding (2.4 log CFU cm(-2) and 29 and 20%, respectively), polishing (3.7 log CFU cm(-2)), and chilling (2.6 log CFU cm(-2) and 55 and 77%, respectively) and increased (P < 0.05) after the combined dehairing-singeing (4.7 log CFU cm(-2) and 97 and 100%, respectively). Among sites, the neck tended to yield higher levels of contamination from trimming to chilling at both abattoirs (P < 0.05). Consequently, scalding, singeing, and chilling may be integrated in a hazard analysis critical control point (HACCP) system for pig slaughter. As indicated by the higher levels of contamination on carcasses after dehairing-singeing and the following stages at abattoir B, each abattoir should develop its own baseline data and should customize HACCP systems to match process- and site-specific circumstances.