Gastric emptying following brain injury: effects of choice of sedation and intracranial pressure.

OBJECTIVE: To compare the effects of opioid and non-opioid sedation on gastric emptying. DESIGN: Prospective, randomized trial. SETTING: University teaching hospital ICU. PATIENTS: 21 brain injured patients requiring sedation, mechanical ventilation and intracranial pressure (ICP) monitoring for > 24 h. INTERVENTIONS: Patients were randomized to receive infusions of either morphine plus midazolam (M), or propofol (P). Gastric emptying was assessed by the paracetamol absorption technique and by residual volumes following a 200 ml test feed. MEASUREMENTS AND RESULTS: Pre-sedation Glasgow Coma Score, mean ICP and the presence of bowel sounds were noted. Plasma concentrations of paracetamol were measured over 3 h following a 1 g gastric dose. There were no differences in median peak paracetamol concentration (M, 18.5 versus P, 20.8 mg/l), median time to peak concentration (M, 20 versus P, 25 min), median area under the concentration-time curve (AUC), or in the median residual volumes at 1 h (M, 14 versus P, 10.5 ml) and 2 h (M, 5 versus P, 3 ml). In patients with ICP > 20 mmHg, paracetamol concentrations were lower (p < 0.05), and AUC after 30 min was lower (165 mg.min/l versus 411 mg.min/l, p = 0.023). Mean ICP was correlated with AUC (Kendall rank p = 0.027). Gastric emptying did not correlate with initial Glasgow Coma Score or presence of bowel sounds. CONCLUSIONS: Gastric emptying is not improved in patients with brain injury by avoiding morphine (1-8 mg/h) in the sedative regimen. Intracranial hypertension is associated with reduced gastric emptying.

The epidemiology of Salmonella typhimurium in cattle: plasmid profile analysis of definitive phage type (DT) 204c.

During the period 1979-1991, Salmonella Typhimurium DT 204c was the cause of a major epidemic of salmonellosis in calves in the UK. Plasmid profile analysis of DT 204c isolates from England and Wales commenced in 1986 and isolates from all subsequent incidents were examined by this technique. Forty-three different plasmid profile types (PPTs) were detected, of which the commonest, designated type E, constituted 44.6-80.2% of the annual incidents during the study period. Some PPTs, e.g., F and P, were detected throughout most years of the study, whereas PPTs O and 6 persisted for short periods. Until 1984, most isolates were resistant to neomycin, but the subsequent predominant PP type E was sensitive to this antibacterial agent. It was concluded that during the epidemic there was an evolution of new genotypes, of which only some persisted; again, antibacterial resistance genes may be acquired or lost. The study demonstrated the value of PP typing for epidemiological studies.

The use of latex particle agglutination to specifically detect Salmonella enteritidis.

This paper reviews the development and evaluation of a latex particle agglutination test to specifically identify cultured Salmonella enteritidis organisms. The test is based on the use of two monoclonal antibody-coated latex reagents, one of which detects the recently discovered SEF14 fimbriae expressed predominantly by S. enteritidis and S. dublin organisms, while the second reagent detects the H'p' antigen of S. dublin flagella. In a series of field trials 141 out of 142 strains of S. enteritidis from eighteen phage types were correctly identified by the latex test. A further 175 salmonella isolates representing 35 serotypes were tested and only two false-positives (S. dublin) in the latex test were recorded. This is the first rapid serotype specific test for S. enteritidis to be developed, and highlights the potential advantage of fimbrial antigens as novel diagnostic antigens of the future.

Bacterial resistance monitoring of salmonellas isolated from animals, national experience of surveillance schemes in the United Kingdom.

Antimicrobial resistance has been monitored in salmonellas isolated from animals in England and Wales since 1970. The current trends are indicated by comparing the results for the years 1981, 1989 and 1990. Seventy-six per cent of all salmonella isolations are still sensitive to all 16 antimicrobials used for testing. Most antimicrobial resistance is encountered in bovine isolations of Salmonella typhimurium especially phage type DT204C. This phage type, which was initially resistant to at least seven antimicrobials, has however become more susceptible in recent years. Ninety-eight per cent of S. dublin strains from cattle are still sensitive to all the antimicrobials used for testing. Although the number of porcine salmonella isolations is small, many show antimicrobial resistance especially to tetracyclines. A large increase in the number of salmonellas isolated from poultry has occurred in recent years and 75% of these strains are sensitive to all the antibiotics used for testing. Although there has been a slight decrease in the percentage of S. enteritidis strains showing susceptibility 87% of isolations are still sensitive. The emergence of resistance to the newer antimicrobials trimethoprim, apramycin and fluorquinolones has been studied and data presented. The results are discussed with regards to the choice of techniques, bacteria monitored and future surveillance programmes in relation to the veterinary use of antimicrobials.

Bacteriological and serological investigation of persistent Salmonella enteritidis infection in an integrated poultry organisation.

Bacteriological monitoring of broiler breeder farms, the hatchery, rendering plant and animal feed mill during 1991 identified a number of potential cross-contamination hazards, such as the use of processed poultry proteins in the company feed mill and contamination of egg trolleys and trays, which may have led to widespread dissemination of Salmonella enteritidis within an integrated poultry organisation. Serological monitoring of the flocks suggested that, in most cases, substantial exposure to S. enteritidis infection occurred during the mid-rearing stage whereas routine bacteriological monitoring of poultry house litter and dust samples, and meconium samples taken in the hatchery identified infection only after the onset of the laying period. At least 10 phage types and six plasmid profile types of S. enteritidis were identified in historic submissions from the organisation including one apparently specific plasmid profile type that was distributed throughout the various parts of the company. During sampling for this investigation, most of these strains were not identified, and the number of plasmid profile types was reduced to a single common UK type.

Characterisation of monoclonal antibodies against a fimbrial structure of Salmonella enteritidis and certain other serogroup D salmonellae and their application as serotyping reagents.

A panel of 13 monoclonal antibodies from different hybridomas was produced against a novel salmonella fimbrial antigen expressed predominantly by Salmonella enteritidis strains. The specificity of the monoclonal antibodies to this antigen (SEF14) was confirmed by enzyme-linked immunosorbent assay (ELISA) using purified SEF14, immune electron microscopy and, with 11 monoclonal antibodies, the identification of a repeating protein subunit (14,300kDa) on the antigen. Blocking-ELISA with the monoclonal antibodies identified epitopes in at least three, non-overlapping clusters which appeared evenly distributed on SEF14 in immune electron microscopy. The use of the monoclonal antibodies in direct-binding ELISA on a range of salmonella serotypes suggested that the epitopes on SEF14 are highly conserved and were expressed by all the S enteritidis strains examined; some strains of S dublin and the only strain of S moscow available were the only other serotypes that expressed SEF14. A latex agglutination reagent based on a monoclonal antibody was developed and used to test for SEF14 on 280 strains (representing 120 serotypes in 24 serogroups of salmonellae) that had been grown on Sensitest agar for 18 hours at 37 degrees C. All S enteritidis strains (64) and most S dublin strains (28 of 33) produced SEF14 as did the two strains representing S blegdam and S moscow. SEF14 was not detected in any other strains of serotypes from serogroup D or from any other serogroup examined.

Epidemiology of Salmonella typhimurium infection in calves: persistence of salmonellae on calf units.

Salmonella typhimurium DT204C infection is the commonest cause of salmonellosis in calves. On five calf rearing farms a distinct strain, as indicated by plasmid profile analysis, was found to have persisted on the premises for periods ranging from four months to two years, the average being 14 months. The persistence of salmonellae in the environment appears to be an important factor in the epidemiology of calf salmonellosis and clearly indicates the inadequacy of many cleaning and disinfection routines.

Escherichia coli isolated from farm animals in England and Wales between 1986 and 1991.

Escherichia coli isolated from farm animals in England and Wales between 1986 and 1991 were examined for their serogroup, fimbrial adhesin and toxin production, and resistance to antimicrobial drugs. Among the 3595 porcine isolates the more common serogroups were O149, O8, O138, O147 and O157. The F4(K88) adhesin was detected in 21 per cent of the cultures, whereas the other adhesins were never present in more than 3 per cent during any year, although there was an upward trend in the prevalence of the F6(987P) antigen. The heat labile enterotoxin was produced by more than 17 per cent of the cultures usually in association with the F4 antigen. The other toxins, heat stable (STa), verocytotoxin (VT) and cytotoxic necrotising factor (CNF) were produced by 5.3, 4.7 and 6.8 per cent of the cultures, respectively. Among the 1383 bovine cultures the more common serogroups were O8, O101 and O17. The F5(K99) adhesin was detected in 9.1 per cent of the cultures, usually in association with STa production. The toxins STa, VT and CNF were produced by 4.4, 2.8 and 8.3 per cent of the cultures, respectively. Among the 407 ovine isolates the more common serogroups were O8, O101 and O78, and 11 per cent of the cultures produced the F5(K99) antigen. The toxins STa, VT and CNF were produced by 1.5, 6.1 and 9.1 per cent of the cultures, respectively. In the case of the 402 poultry isolates the more common serogroups were O78, O2 and O8, which are usually associated with colisepticaemia. Resistance to antibiotics was common, particularly among the bovine isolates.

Studies on the development and use of a monoclonal sandwich ELISA for the detection of verotoxic Escherichia coli in animal faeces.

A sandwich ELISA using monoclonal antibodies to Escherichia coli verocytotoxins 1 and 2 for capture and detection was developed for detection of verocytotoxin-producing Escherichia coli (VTEC) in animal faeces. For optimal toxin detection, the faeces were cultured in MacConkey broth before subculture on to trypticase soy agar containing mitomycin C. It was possible to detect between 10 and 10(3) VTI-producing and 1 to 10 VT2-producing E coli/g faeces, and overall the sensitivity and specificity of the ELISA for VTEC in faeces were 80.5 per cent and 91.2 per cent, respectively, when compared with a verocell assay. A limited survey of faeces from healthy animals (89 cattle, 16 sheep, 22 pigs, 11 goats and six domestic fowl) and faeces from 144 cattle with enteric disease detected VTEC in 64 per cent, 63 per cent, 5 per cent, 45 per cent, none and 16 per cent of the samples, respectively.

Observations on the distribution of Salmonella in a pig abattoir.

A survey of 2211 pigs was carried out in a pig abattoir. Salmonella was isolated from 7-0 per cent of carcase swabs and from 11.6 per cent of 2205 samples of large intestinal contents. Salmonella typhimurium DT104 or DT104B was found in 3.2 per cent of the large intestinal samples (27.7 per cent of the salmonella isolates found) and in 2.7 per cent of the carcase swabs (38.7 per cent of the salmonella isolates from carcases). Within individual batches of pigs, the rate of isolation of salmonella ranged from 0 to 71.4 per cent from intestinal contents, and from 0 to 100 per cent on carcases. In a smaller subsurvey, salmonella was found in 9.1 per cent of intestinal contents, 5.8 per cent of mesenteric lymph nodes and 3.8 per cent of tonsils, but in no spleen samples. The rates of isolation of salmonella from pigs from different producer groups ranged from 0 to 21.9 per cent with 0 to 88.2 per cent of farm units within groups showing evidence of infection. S typhimurium DT104 or DT104B was isolated from large intestinal samples from 16.9 per cent of farm units. The number of salmonellae found in positive pigs ranged from 1.0 to 10(5) cfu/g intestinal contents and from 1.0 to 10(2) cfu per 0.1 m2 dressed carcase surface. Sequential sampling during the slaughter process showed that 82.9 per cent of the carcases were contaminated after bleeding, a proportion which was reduced to 5.7 per cent after scalding; after singeing none were contaminated. Estimations of surface enterobacteriaceae revealed a similar pattern of reductions and resurgences of contamination to that observed with salmonella. The rate of isolation of salmonella from pigs which had been held in lairage overnight was less than that from pigs slaughtered within two to three hours of arrival.

Differentiation of Salmonella senftenberg into biogroups.

Ninety-six strains of Salmonella senftenberg, isolated between 1984 and 1986 from different parts of England and Wales, were tested for their biochemical reactions and biotyped according to the method of Duguid and others (1975). Nine biogroups were identified on the basis of their metabolism of L-tartrate, D-tartrate, Bitter's xylose and Stern's glycerol. In addition, fumaric, oxalic, succinic, glutaric, malonic, maleic, L-malic, L-aspartic, lactic and formic acids were used but did not increase the discrimination. Three biogroups (7, 2 and 5) accounted for 79 per cent of the cultures examined.

An interlaboratory trial of a latex agglutination kit for rapid identification of Salmonella enteritidis.

An interlaboratory trial was conducted of a latex agglutination kit for the rapid identification of Salmonella enteritidis, to assess the stability of the components and its performance with respect to a panel of three coded salmonellas and 243 field isolates. Two of the components of the kit deteriorated with time. All 62 isolates of S enteritidis were correctly identified by the kit; only two false positives were recorded and no false negatives.

Natural and experimental infection of normal cattle with Escherichia coli O157.

The objective of the study was to determine the effects of inoculating cattle orally with a strain of Escherichia coli O157:H7 (A84/92). However, before they were challenged two of the six calves were found to be infected naturally with a wild-type strain of E coli O157 and two more of them became infected later. The number of daily faeces samples from which the wild-type E coli O157 was isolated ranged from one to 10. After they were inoculated, A84/92 was detected in all the calves' faeces on one to six of the next 14 days, and later from the faeces samples of three calves on two, three, and 11 occasions, the last occasion being between 19 and 51 days after inoculation. Two calves were redosed with A84/92, and the organism was isolated on a further five and 15 occasions, the last being after 20 and 58 days. In three dry cows, A84/92 was isolated from the faeces on three to 11 of the 14 days after they were inoculated. Two of the cows were redosed and from one of them it was isolated on 15 occasions, the last being 44 days after the initial infection; in the other cow no further isolation was made. In three lactating cows, it was detected on three to four of the 14 days after they were inoculated, and similar results were obtained after they were reinoculated. None of the animals showed clinical signs and no lesions were detected in the intestines of the calves. Three calves had a serological response to E coli O157 but, with the exception of one cow which had a slight increase to IgM levels, no serological changes were observed in the adult cattle.

Antimicrobial resistance in Salmonella isolated from animals and their environment in England and Wales from 1988 to 1999.

Resistance to 16 antimicrobial agents was monitored in 109,125 Salmonella cultures isolated from animals, their environment and feedstuffs between 1988 and 1999. The sensitivity of the 6512 isolates of Salmonella enterica enterica serotype Dublin to all the antimicrobial agents tested varied from 98.2 per cent in 1997 to 99.7 per cent in 1990 and 1996. In contrast, among 28,053 isolates of Salmonella enterica enterica serotype Typhimurium, there was a marked decrease in their sensitivity to all the antimicrobial agents tested, from 57.4 per cent in 1992 to 7.6 per cent in 1995, owing to the widespread occurrence in farm animals of S Typhimurium isolates of the definitive type DT104, resistant to ampicillin, sulphonamides, streptomycin, chloramphenicol and tetracyclines, although the percentage of sensitive isolates increased to 18.4 per cent in 1999, when the incidence of DT104 had decreased. Some isolates of DT104 also showed an increase in resistance to potentiated sulphonamides (2.4 per cent in 1989 to 19.2 per cent in 1999) and nalidixic acid (0 per cent in 1992, 3.8 per cent in 1995 to a peak of 16.9 per cent in 1998). In 1996, 5.1 per cent of 1086 isolates of S Typhimurium from cattle and 35.9 per cent of 192 isolates of S Typhimurium from poultry showed resistance to nalidixic acid. Of the other 74,528 Salmonella isolates, the percentage of strains sensitive to all the antimicrobials tested decreased slightly from 88.2 per cent in 1988 to 70.6 per cent in 1996 and then increased slightly to 73.7 per cent in 1999. The commonest of these other Salmonella serotypes was Salmonella Enteritidis (20,982), which remained predominantly susceptible (ranging from 81.4 to 97.4 per cent) during the study period. Few isolates were resistant to commonly used veterinary antimicrobials, for example, furazolidone, the use of which was banned in 1990, and the aminoglycoside, apramycin.

Infection of gnotobiotic calves with Escherichia coli o157:h7 strain A84.

Six colostrum-deprived, hysterotomy-derived calves were maintained under sterile conditions and fed a milk replacer diet. At five days of age, five of the calves were dosed orally with 10(9) cfu of Escherichia coli O157:H7 strain A84. They were killed after, one, two, six, 12 and 24 days, and samples were taken for bacteriological and pathological examination. The sixth uninfected control calf was killed at seven days of age and matched samples were taken for pathological comparison. The animals remained normal throughout the observation period. Bacteriological data indicated a heavy bacterial load of strain A84 throughout the gastrointestinal tract but the bacterium was not found in liver, kidney or muscle. No evidence of 'attaching and effacing' lesions in the small or large intestine was found although there was a mild inflammatory response in the intestinal tract, consisting mainly of infiltrating eosinophils.

Causes of death of wild birds of the family Fringillidae in Britain.

The provision of supplementary food for wild birds in gardens during the winter months is common in the UK, but it is possible that it may precipitate infectious diseases in the birds. This paper describes the results of postmortem examinations of 116 wild finches carried out over a period of four years. The two commonest causes of death in areas where high mortality had been reported were infections with the bacteria Salmonella typhimurium DT40 and Escherichia coli O86. Coccidia of the genera Atoxoplasma or Isospora were found in several of the birds but were considered to be incidental. Megabacteria were also identified in some of the birds, for the first time in flocks of wild birds in the UK, but they were not considered to be significant.

Prevalence of faecal excretion of verocytotoxigenic Escherichia coli O157 in cattle in England and Wales.

During the decade to 1999, the incidence of human infections with the zoonotic pathogen verocytotoxin-producing Escherichia coli O157 (VTEC O157) increased in England and Wales. This paper describes the results of a survey of 75 farms to determine the prevalence of faecal excretion of VTEC O157 by cattle, its primary reservoir host, in England and Wales. Faecal samples were collected from 4663 cattle between June and December 1999. The prevalence of excretion by individual cattle was 4.2 per cent (95 per cent confidence interval [CI] 2.0 to 6.4) and 10.3 per cent (95 per cent CI 5.8 to 14.8) among animals in infected herds. The within-herd prevalence on positive farms ranged from 1.1 to 51.4 per cent. At least one positive animal was identified on 29 (38.7 per cent; 95 per cent CI 28.1 to 50.4) of the farms, including dairy, suckler and fattening herds. The prevalence of excretion was least in the calves under two months of age, peaked in the calves aged between two and six months and declined thereafter. The phage types identified most widely were 4, 34 and 2, which were each found on six of the 29 positive farms.

Abattoir based survey of Salmonella in finishing pigs in the United Kingdom 2006-2007.

All European Union (EU) Member States (MSs) were required to conduct a baseline survey from October 2006 to September 2007 to estimate the prevalence of Salmonella infection in finisher pigs at slaughter. In the United Kingdom (UK), samples for microbiological culture were collected from the ileo-caecal lymph nodes, from carcass swabs and from caecal contents. Meat juice samples were also collected for testing in an enzyme-linked immunosorbent assay (MJE) to detect a serological response. Salmonella was isolated from 22% (CI95% 19-25%) of ileo-caecal lymph nodes, 15% (CI95% 12-18%) of carcass swabs and 22% (CI95% 19-26%) of caecal contents. A quarter (25%, CI95% 22-29%) of MJE samples were positive for Salmonella antibodies (cut-off, S/P≥0.25). The most frequently identified serovars were Salmonella typhimurium (57%) and Salmonella derby (26%). The results were used to investigate some factors associated with Salmonella infection in slaughter pigs. The weight of the carcass was significant, with a lower probability of obtaining a positive meat juice result from pigs with a weight greater than 75 kg (p=0.03). The weight of the lymph node sample was significantly associated with Salmonella status, with a heavier sample of lymph nodes being more likely to be positive (OR=2.16 CI95% 1.07-4.39). 'Carcass weight' in two of the classes - 75-79 kg and 80-84 kg - (OR=0.44 CI95% 0.28-0.70; OR=0.64 CI95% 0.49-0.85) and 'fewer-than-1500-pigs' scheduled for slaughter on the day of sampling' (OR=0.41 CI95% 0.24-0.71) were also associated with a reduced risk of isolating Salmonella from lymph node. The model for carcass swabs showed a positive association with 'time-elapsed-since-the-start-of-the-line' indicating a higher risk of contamination as the day progressed (p<0.01). This model also showed positive association between isolation of Salmonella from a carcass swab and the occurrence of Salmonella in caecal contents from the same pig (OR=2.22 CI95% 1.38-3.59) and a negative association with time in singeing units (OR=0.88 CI95% 0.79-0.98).

Investigation of the Distribution of Salmonella within an Integrated Pig Breeding and Production Organisation in the United Kingdom.

To examine patterns of Salmonella herd infections in units linked by common sources of pigs, the study examined pooled pen faeces samples from 161 nursery and finishing units in a UK integrated pig enterprise. An epidemiological questionnaire was also completed by investigators for each farm. Salmonella was isolated from 630 (19.5%) of the samples: S. Typhimurium was found in 387 (12%) and S. Derby in 157 (4.9%) samples; 111 units yielded at least one sample containing Salmonella. The proportion of Salmonella-positive samples from positive farms ranged from 5% to 95%. In a univariable risk factor analysis, increasing length of time as a pig farm was positively associated with the detection of Salmonella in a herd. Larger farms (>500 pigs) were significantly more likely to be positive for S. Typhimurium than smaller farms. There was an association between Salmonella serovars isolated in the present study and those subsequently isolated in breeding herds linked to the integration.