A low-cost towed video camera system for underwater surveys: comparative performance with standard methodology.

Technological advances in the field of underwater video have led to an exponential increase in the use of drifting cameras (DC) and remotely operated vehicles (ROVs) to monitor the diversity, abundance, and size structure of marine life. Main advantages of DCs relative to ROVs are their lower costs and the much simpler logistics required to operate them. This study compares the performance of a new low-cost DC system equipped with a novel measuring device with that of a standard DC bearing an array of laser pointers. The new DC, which can be operated from a small boat, carries a pair of parallel steel "whiskers" that are dragged on the seabed within the field of view of the camera, providing a scale for measuring and estimating the density of benthic biota. An experiment conducted using an array of objects of known sizes laid on the bottom showed that its performance in terms of both size and density estimation was similar to that of the standard technique based on laser pointers. Measurement errors had a negligible negative bias (- 2.3%) and a standard deviation that ranged between 13 and 8% for objects from 25 to 110 mm in size. The whiskers offered a simplified method for density estimation that avoids the need to calculate the width of the field of view, thus reducing the video processing time by around 60% with respect to the standard method. Briefly, the new system offers an efficient low-cost alternative for benthic ecology studies conducted on soft or non-irregular bottoms.

Comment on "Tracking the global footprint of fisheries".

Kroodsma et al (Reports, 23 February 2018, p. 904) mapped the global footprint of fisheries. Their estimates of footprint and resulting contrasts between the scale of fishing and agriculture are an artifact of the spatial scale of analysis. Reanalyses of their global (all vessels) and regional (trawling) data at higher resolution reduced footprint estimates by factors of >10 and >5, respectively.

Dynamic of mutational events in variable number tandem repeats of Escherichia coli O157:H7.

VNTRs regions have been successfully used for bacterial subtyping; however, the hypervariability in VNTR loci is problematic when trying to predict the relationships among isolates. Since few studies have examined the mutation rate of these markers, our aim was to estimate mutation rates of VNTRs specific for verotoxigenic E. coli O157:H7. The knowledge of VNTR mutational rates and the factors affecting them would make MLVA more effective for epidemiological or microbial forensic investigations. For this purpose, we analyzed nine loci performing parallel, serial passage experiments (PSPEs) on 9 O157:H7 strains. The combined 9 PSPE population rates for the 8 mutating loci ranged from 4.4 × 10(-05) to 1.8 × 10(-03) mutations/generation, and the combined 8-loci mutation rate was of 2.5 × 10(-03) mutations/generation. Mutations involved complete repeat units, with only one point mutation detected. A similar proportion between single and multiple repeat changes was detected. Of the 56 repeat mutations, 59% were insertions and 41% were deletions, and 72% of the mutation events corresponded to O157-10 locus. For alleles with up to 13 UR, a constant and low mutation rate was observed; meanwhile longer alleles were associated with higher and variable mutation rates. Our results are useful to interpret data from microevolution and population epidemiology studies and particularly point out that the inclusion or not of O157-10 locus or, alternatively, a differential weighting data according to the mutation rates of loci must be evaluated in relation with the objectives of the proposed study.

Distribution of additional virulence factors related to adhesion and toxicity in Shiga toxin-producing Escherichia coli isolated from raw products in Argentina.

UNLABELLED: A total of 73 Shiga toxin-producing Escherichia coli (STEC) isolates, belonging to 25 serotypes and isolated from raw products in Argentina, were examined for the occurrence of genes responsible for bacterial adhesions to intestine, ehaA (EHEC autotransporter), lpfAO113 (long polar fimbriae), sab (STEC autotransporter [AT] contributing to biofilm formation), ecpA (E. coli common pilus), hcpA (haemorrhagic coli pilus), elfA (E. coli laminin-binding fimbriae), sfpA (sorbitol-fermenting EHEC O157 fimbriae plasmid-encoded) and of the toxigenic gene cdt-V (cytolethal distending toxin). Our study showed different adhesin profiles that are not linked to one specific serotype and that all analysed isolates possess, besides stx genes, some adherence genes. Several of the isolates contained also multiple toxin genes. The results of the present work alert the presence of genes coding for additional adhesins and cdt-V toxin in LEE-negative STEC strains that occur in foods, and this traits could increase their pathogenic potential. SIGNIFICANCE AND IMPACT OF THE STUDY: Meat products are one of the main vehicles of Shiga toxin-producing E. coli, and the presence of genes coding for additional adhesins and toxins could increase their pathogenic potential. There is a need for a more detailed characterization of the strains in regard to these extra virulence factors.

Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies.

Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-Stx2B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx(2EDL933), stx(2vha), stx(2vhb), stx(2g), stx(1EDL933), and stx(1d) were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 115 ng/ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for two strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli.

Short communication: characterization of Shiga toxin-producing Escherichia coli isolated from newborn, milk-fed, and growing calves in Argentina.

Shiga toxin-producing Escherichia coli (STEC) cause foodborne pathogenic disease that is shed in the feces of cattle. The aim of this study was to evaluate how early young calves are colonized by STEC strains, potentially pathogenic for humans, and the prevalence in different calf categories. From 808 rectal swabs analyzed by PCR, 38% were stx positive. The prevalence in newborn (<24 h from birth), milk-fed (<2-mo-old), and growing calves (2-8 mo old) were 25, 43, and 58%, respectively. Forty different STEC serotypes were found among isolates from newborn, milk-fed, and growing calves that shed STEC strains potentially pathogenic for humans. The STEC strains could be acquired early from mothers, enabling the infection of other animal categories and confirming the risk to public health.

Seasonal variation of HUS occurrence and VTEC infection in children with acute diarrhoea from Argentina.

In order to study the seasonality of haemolytic uraemic syndrome (HUS) and verotoxigenic Escherichia coli (VTEC) infection in children, 437 patients under 6 years of age with acute diarrhoea were studied, 8% of whom progressed to HUS. VTEC was found in 10% of all of the stool samples analysed and seasonal occurrence of HUS (p < 0.01) was confirmed. VTEC infection was more prevalent in warm months, although the differences were not statistically significant. Moreover, a significant difference in the detection of O157:H7 serotype and in the vt profile between cold and warm months (autumn and winter; spring and summer, respectively) was established. The O157:H7 serotype was isolated more frequently during warm months. Moreover, a predominance of vt (2) was noted, which was partially replaced by the combination of vt (1) with vt (2) in the cold season. The results of this study indicate the seasonal variation of the disease and the presence of serotype O157:H7 and the vt types. They also reinforce the need to develop prevention programmes considering the seasonal pattern of the disease, which would generate an impact on public health. Control strategies of the pathogen in cattle in the most risky season of the year would also be of benefit.

Enteropathogenic Escherichia coli contamination at different stages of the chicken slaughtering process.

Enteropathogenic Escherichia coli is a foodborne pathogen that produces potentially fatal infant diarrhea, noticeably in developing countries. The aim of this study was to detect EPEC contamination by PCR at different stages of the chicken slaughtering process. We collected swabs from chicken cloacae and washed carcasses (external and visceral cavity) during the slaughtering process in 3 sampling occasions. Unwashed eviscerated carcasses were also sampled (at the visceral cavity) in the second and third sampling occasions. Enteropathogenic Escherichia coli was detected in 6 to 28% of cloacal samples, 39 and 56% of unwashed eviscerated carcasses, and 4 to 58% of washed carcasses. None of the samples were positive for bfpA, suggesting contamination with atypical EPEC. The detection of EPEC at different stages of the chicken slaughtering process showed that the proportion of contaminated samples remained or even increased during processing. In addition, the high proportion of contaminated carcasses during chicken processing represents a risk for the consumers and a challenge to improve procedures for those working in the sanitary control service.

Multiplex PCR assay for the detection of five putative virulence genes encoded in verotoxigenic Escherichia coli plasmids.

The aim was to perform a pentavalent PCR assay for the detection of putative virulence genes encoded in VTEC plasmids, katP, espP, subA, stcE, and ehxA. The five-specific primer pairs used in the assay do not interfere with each other and generate amplification products of 914, 774, 556, 399, and 262 bp. It was selected at random 39 strains belonged to 20 serotypes in order to evaluate the multiplex in a wide variety of strains. The results of this study indicate that it is possible to perform simultaneous amplification and search for recognized plasmid-encoded virulence markers from different E. coli serotypes and apply this technique to the genetic characterization of E. coli strains isolated from reservoirs, foods or patients. This complementary technique is a useful tool to detect interstrain differences for epidemiological studies and to provide information that could be related to the risk of human infection.

Reduction of Adherence of E. coli O157:H7 to HEp-2 Cells and to Bovine Large Intestinal Mucosal Explants by Colicinogenic E. coli.

Enterohemorrhagic E. coli strains (EHEC) had emerged as foodborne pathogens and cause in human diarrhea and hemolytic-uremic syndrome. Because of the widespread distribution of EHEC serotypes and O157 and non-O157 in cattle population, its control will require interventions at the farm level such as the administration of probiotics that produce inhibitory metabolites. E. coli O157:H7 shows tissue tropisms for the gastrointestinal tract (GIT) of cattle. The aim of this study was to test the ability of a colicinogenic E. coli (isolated from bovine) to reduce the adherence of E. coli O157:H7 to HEp-2 cells and to GIT of cattle. We inoculated HEp-2 cells and bovine colon explants with both kinds of strains. Colicinogenic E. coli was able to reduce the adherence of E. coli O157:H7 to HEp-2 cells and to bovine tissues.

Characterization of Shiga toxin-producing Escherichia coli isolated from dairy cows in Argentina.

AIMS: To feno-genotypically characterize the Shiga toxin-producing Escherichia coli (STEC) population in Argentinean dairy cows. METHODS AND RESULTS: From 540 STEC positive samples, 170 isolates were analyzed by multiplex PCR and serotyping. Of these, 11% carried stx1, 52% stx2 and 37% stx1/stx2. The ehxA, saa and eae were detected in 77%, 66% and 3%, respectively. Thirty-five per cent of strains harboured the profile stx1, stx2, saa, ehxA and 29% stx2, saa, ehxA. One hundred and fifty-six strains were associated with 29 different O serogroups, and 19 H antigens were distributed among 157 strains. STEC O113:H21, O130:H11 and O178:H19 were the most frequently found serotypes. The STEC O157:H7 were detected in low rate and corresponded to the stx2(+) , eae(+) , ehxA(+) virulence pattern. CONCLUSIONS: We detected a diversity of STEC strains in dairy cattle from Argentina, most of them carrying genes linked to human disease. SIGNIFICANCE AND IMPACT OF THE STUDY: The non-O157 STEC serotypes described in this study are associated worldwide with disease in humans and represent a risk for the public health. For this, any microbiological control in dairy farms should be targeted not only to the search of O157:H7 serotype.

Occurrence of Shiga toxin-producing E. coli (STEC) on carcasses and retail beef cuts in the marketing chain of beef in Argentina.

Argentina has the highest incidence of HUS in the world. HUS is produced by STEC O157 and non-O157. Cattle's faeces and hides are sources of STEC contamination of carcasses during slaughter. We investigated the presence of STEC in carcasses and cuts of meat in the marketing chain in an agricultural city located in Buenos Aires Province (Argentina). In this study, the detection of the stx gene was used as an indicator of carriage of meat with STEC. In carcasses, we detected 12.34% and 18.64% of STEC at the slaughter and sanitary control cabin (place where carcasses arrive from slaughters located outside the city), respectively. These percentages increased at butcheries (24.52%). The 25% of retail beef cuts were STEC-positive with significant differences among the different cuts of meat (chuck: 12.12%, rump roast: 12.12% and minced beef: 40.74%). The stx2 gene was the predominant gene detected in all samples at different levels of the commercialization meat chain.

Seasonal variation of Shiga toxin-encoding genes (stx) and detection of E. coli O157 in dairy cattle from Argentina.

AIMS: To study the seasonal variation of Shiga toxin-encoding genes (stx) and to investigate the presence of Shiga toxin-producing Escherichia coli (STEC) O157 in cattle belonging to five dairy farms from Argentina. METHODS AND RESULTS: Rectal swab samples were collected from 360 dairy cows in each season and 115 and 137 calves in autumn and in spring, respectively. The stx were investigated by multiplex PCR and it was used as the indicator for STEC. Samples positives for stx were tested by PCR for eae-gamma1 of E. coli O157 and then subjected to IMS (immunomagnetic separation). In positive animals significant differences in the prevalence of stx between warm and cold seasons were detected. In warm seasons, stx1 + stx2 increased and stx1 decreased, independently of the animal category. The prevalence of STEC O157 in cows and calves were 0.2% and 0.8%, respectively. CONCLUSIONS: This work provides new data about the occurrence of stx and STEC O157 in dairy herds from Argentina and suggests a relationship between the type of stx and season of year. SIGNIFICANCE AND IMPACT OF STUDY: The detection of STEC O157 and the seasonality of stx and its types provide an opportunity to improve control strategies designed to prevent contamination of food products and transmission animal-person.

Food partitioning and spatial subsidy in shelter-limited fishes inhabiting patchy reefs of Patagonia.

The diets of the most conspicuous reef-fish species from northern Patagonia, the carnivorous species Pseudopercis semifasciata, Acanthistius patachonicus, Pinguipes brasilianus and Sebastes oculatus were studied. Pinguipes brasilianus had the narrowest diet and most specialized feeding strategy, preying mostly on reef-dwelling organisms such as sea urchins, limpets, bivalves, crabs and polychaetes. The diet of A. patachonicus was characterized by the presence of reef and soft-bottom benthic organisms, mainly polychaetes, crabs and fishes. Pseudopercis semifasciata showed the broadest spectrum of prey items, preying upon reef, soft-bottom and transient organism (mainly fishes, cephalopods and crabs). All S. oculatus guts were empty, but stable-isotope analyses suggested that this species consumed small fishes and crabs. In general, P. brasilianus depended on local prey populations and ate different reef-dwelling prey than the other species. Pseudopercis semifasciata, A. patachonicus and probably S. oculatus, however, had overlapping trophic niches and consumed resources from adjacent environments. The latter probably reduces the importance of food as a limiting resource for these reef-fish populations, facilitating their coexistence in spite of their high trophic overlap.

Pheohyphomycotic soft tissue disease caused by Alternaria alternata in a kidney transplant patient: a case report and literature review.

A 61-year-old Italian man, who underwent a renal transplantation 8 years ago, receiving azathioprine, prednisone, and cyclosporine for immunosuppressive therapy, presented with a large reddish indurated plaque with a central ulcer, which was slowly enlarged, on the right knee. From the diseased tissue biopsy, a dematiaceous fungus matching Alternaria alternata in all essential characters was isolated in pure culture. This is an uncommon fungal complication in a kidney transplant patient. A detailed morphological description of the isolate is provided as well as review of the literature.

Escherichia coli with anti-O157:H7 activity isolated from bovine colon.

AIMS: To isolate bacteria from bovine gastrointestinal tract and investigate their inhibitory effect on Escherichia coli O157:H7 in vitro. METHODS AND RESULTS: A total of 2400 bacterial colonies were isolated from cattle colonic mucous membrane. Thirteen strains demonstrated the ability to inhibit the growth of E. coli O157:H7. From these, seven were screened for the presence of virulence factors as: stx(1), stx(2), ehxA, eae, st1a and lt1 by polymerase chain reaction. The selected bacteriocin-producing bacteria showed susceptibility to most of the antibiotics used. CONCLUSIONS: The strains of E. coli isolated, which exhibit inhibitory activity on E. coli O157:H7 growth by the production of inhibitory substances, may be useful in the control of this pathogen in reservoirs. An important characteristic of these strains was the absence of any of the virulence factors assayed and the susceptibility to most of the antibiotics used for Gram-negative bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: These microorganisms might be used as probiotic bacteria to reduce the carriage of E. coli O157:H7 in cattle, thus limiting the contamination of carcasses at slaughter and subsequently the contamination of foods and the transfer of this pathogen to man.

[Isolation and characterization of Shiga-toxin-producing Escherichia coli from frozen hamburgers and soft cheeses]. / Aislamiento y caracterización de Escherichia coli productor de toxina Shiga en hamburguesas supercongeladas y quesos de pasta blanda.

Shiga toxin producing-Escherichia coli (STEC), an important emerging foodborne pathogen, has been associated with bloody and non-bloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura. The cattle have been shown to be a major reservoir of STEC and raw foods such as ground beef and milk are the most common vehicles of infection. In the present study, the prevalence of STEC in 95 samples of frozen hamburgers and in 114 samples of soft cheese was established in 8.4% and 0.9%, respectively. The genotypic and phenotypic characteristics of the strains were determined. The virulence genes stx1, stx2, eaeA and EHEC-hlyA were identified by PCR and by colony blot hybridization assays. Serotyping, antimicrobial susceptibility and production of Stx using specific cytotoxicity assays on Vero cells were also determined. All STEC strains were characterized as eaeA-/EHEC-hlyA+. The stx2 genotype was prevalent (77.8%), and four different O:H serotypes were found, comprising: O8:H19 (5 strains), O113:H21 (1), O8:H16 (1), and O39:H49 (1). One STEC strain was nontypable. Although soft cheese complimented the microbiological quality controls for the coliform counts, the detection of STEC in one sample raises doubts concerning the effectiveness of the current quality controls. These data contribute to the implementation of strategies for the prevention and control of HUS.

Aislamiento y caracterización de Escherichia coli productor de toxina Shiga en hamburguesas supercongeladas y quesos de pasta blanda. / [Isolation and characterization of Shiga-toxin-producing Escherichia coli from frozen hamburgers and soft cheeses]

Shiga toxin producing-Escherichia coli (STEC), an important emerging foodborne pathogen, has been associated with bloody and non-bloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura. The cattle have been shown to be a major reservoir of STEC and raw foods such as ground beef and milk are the most common vehicles of infection. In the present study, the prevalence of STEC in 95 samples of frozen hamburgers and in 114 samples of soft cheese was established in 8.4

and 0.9

, respectively. The genotypic and phenotypic characteristics of the strains were determined. The virulence genes stx1, stx2, eaeA and EHEC-hlyA were identified by PCR and by colony blot hybridization assays. Serotyping, antimicrobial susceptibility and production of Stx using specific cytotoxicity assays on Vero cells were also determined. All STEC strains were characterized as eaeA-/EHEC-hlyA+. The stx2 genotype was prevalent (77.8

), and four different O:H serotypes were found, comprising: O8:H19 (5 strains), O113:H21 (1), O8:H16 (1), and O39:H49 (1). One STEC strain was nontypable. Although soft cheese complimented the microbiological quality controls for the coliform counts, the detection of STEC in one sample raises doubts concerning the effectiveness of the current quality controls. These data contribute to the implementation of strategies for the prevention and control of HUS.

[Chest pain and acute myocardial infarction at the emergency department: diagnostic and therapeutic approaches. Experience of the San Camillo Hospital in Rome]. / Dolore toracico e infarto miocardico acuto in Pronto Soccorso: percorsi diagnostici e terapeutici. L'esperienza dell'Ospedale San Camillo di Roma.

BACKGROUND: Identification and treatment of patients with acute chest pain due to acute coronary syndrome is a common and difficult challenge for emergency physicians. The aim of this study was to establish: a) the reliability of diagnosis of acute myocardial infarction met in the emergency ward, b) the length of the patient's hospital stay with acute myocardial infarction discovered and treated in the emergency ward either with primary angioplasty or with thrombolysis. METHODS: We analyzed the data collected in the emergency ward of the San Camillo Hospital in Rome from January 1 to June 30, 2000, with patients suffering from chest pain and diagnosis after hospitalization. The reliability of diagnosis of acute myocardial infarction was calculated from the comparison of the diagnosis in the emergency ward and the diagnosis at hospital discharge. RESULTS: From January 1 to June 30, 2000, 45,810 patients have asked for help at the emergency ward; 2334 (5.1%) of these were suffering from chest pain. The diagnosis of acute myocardial infarction was done in the emergency ward in 147 cases (141 hospitalized, 4 deceased, and 2 transferred to other hospitals), equal to 65% of all those discharged with the same diagnosis in the period under examination. In 66 out of the 141 cases hospitalized (46.8%) primary angioplasty was successfully performed; in 14 (9.9%) only coronary angiography was performed (primary angioplasty unfeasible); in 22 (15.6%) thrombolysis was administered whereas in 38 cases (27.0%) other treatments were used. The average stay for the different groups turned out to be 9.8 +/- 4 days for primary angioplasty and 12.9 +/- 4 days for thrombolysis: the difference was relevant. CONCLUSIONS: The accuracy value of the diagnosis of acute myocardial infarction made in the emergency ward of our Hospital is the same as that published in the international literature and demonstrates the high level of treatment of chest pain. Furthermore, the shorter hospital stay obtained by primary angioplasty in comparison with thrombolysis seems to strengthen the already favorable cost-benefit ratio of primary angioplasty in comparison with thrombolysis.

Early translaryngeal tracheostomy in patients with severe brain damage.

OBJECTIVES: To describe the effects of early translaryngeal tracheostomy on intracranial pressure (ICP), cerebral perfusion pressure (CPP), and jugular bulb saturation (SjO2); to identify the main mechanisms affecting ICP during tracheostomy; and to evaluate the long-term effects of tracheostomy on tracheal anatomy and function. DESIGN: Prospective, observational, clinical study. SETTING: Neurosurgical intensive care unit in a teaching hospital. PATIENTS: 20 patients admitted to the ICU because of head injury, subarachnoid hemorrhage, or brain tumor with a Glasgow Coma Scale less than 8. INTERVENTIONS: Patients underwent translaryngeal tracheostomy under strict neuromonitoring. MEASUREMENTS AND RESULTS: ICP rose significantly (p < 0.05) at the critical time of cannula placement while all other parameters remained stable. At this time five patients suffered intracranial hypertension (ICP > 20 mmHg). In one of them CPP dropped below 60 mmHg. Arterial CO2 tension (PaCO2) did not rise significantly. No other major complications were recorded during the procedures. Three months after tracheostomy normal findings were detected by tracheoscopy in all cases (11 patients could be examined). CONCLUSIONS: Translaryngeal tracheostomy, performed in selected patients when the risk of intracranial hypertension was reduced to the minimum, was well tolerated in the majority of cases and did not induce persistent intracranial disorders. However, ICP is affected by tracheostomy, and careful monitoring and patient selection is necessary. At follow-up no severe anatomical or functional damage was detected.