bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasmid-determined antibiotic resistance inShigella flexneriisolated in England and Wales between 1974 and 1978
Authors: Frost J. A. , Rowe B.
Published: October 2009

The majority ofShigella flexneristrains isolated in England and Wales are from infections contracted abroad. Most of these strains are drug-resistant, over 75% being resistant to streptomycin and sulphonamides, sulphonamides alone or streptomycin, sulphonamides and tetracyclines. A selection of resistant strains was tested for resistance transfer and the plasmids identified were characterized by compatibility grouping.

Streptomycin and sulphonamide resistance was usually determined by a non-autotransferring plasmid which may be mobilized by standard transfer factors, or by the plasmid which conferred tetracycline resistance where this was present. The remaining resistant strains were predominantly resistant to four or more drugs. These strains carried autotransferring plasmids of a variety of compatibility groups, of which groups B, I1and FIIwere the most common.
Effect of various oral dose levels of a trimethoprim/sulphadiazine mixture on Bordetella bronchiseptica infection and on the proliferation of trimethoprim-resistant faecal coliforms in pigs
Authors: Dassanayake L. , White G.
Published: October 2009

When a 1:5 mixture of trimethoprim (TMP) and sulphadiazine was fed to pigs intra-nasally infected with Bordetella bronchiseptica, 10 mg/kg/day was shown to be highly effective in suppressing the organism. This dose level had little effect on numbers of TMP-resistant coliforms in faeces, but oral doses of 30 mg/kg/day eventually selected a resistant population. It is suggested that the proliferation of resistant coliforms would be minimized by administration of the lowest oral dose rates of antibacterial drugs compatible with efficacy.
Plasmid-encoded trimethoprim resistance in salmonellas isolated in Britain between 1970 and 1981
Authors: Threlfall E. J. , Frost Jennifer A. , King Hilary C. , Rowe B.
Published: October 2009

Trimethoprim resistance was plasmid-encoded in all trimethoprim-resistant Salmonella typhimurium and in the majority of trimethoprim-resistant salmonellas of other serotypes isolated since 1970 from humans and food animals in Britain. In S. typhimurium, non-autotransferring plasmids of compatibility group 3 and autotransferring plasmids of group H2 predominated. The predominance of these plasmid types has resulted from the spread of clones of trimethoprim-resistant strains of phage types 18,170 and 204c. In other salmonellas, a variety of plasmid compatibility groups have been identified. Almost all plasmids which conferred resistance to trimethoprim also coded for sulphonamide resistance.
Comparison of radioimmunoassay with the complement fixation test and the indirect haemolysis test in the field diagnosis of bovine brucellosis
Authors: Chappel R. J. , Hayes J.
Published: October 2009

Sera were collected from female cattle in 118 commercial herds being subjected to a programme to eradicate brucellosis by test and slaughter, in an area in which vaccination of heifer calves with Brucella abortus strain 19 was compulsory. Of 4583 sera positive by the Rose Bengal plate test, the brucellosis radioimmunoassay was positive for 1524, the complement fixation test for 1363 and the indirect haemolysis test for 1141. These figures, and supporting evidence from the eradication programme, suggest that the radioimmunoassay may be a useful supplementary test in problem herds.
The serotyping of hospital strains of streptococci belonging to Lancefield group C and group G
Authors: Efstratiou Androulla
Published: October 2009

A collection of more than 300 strains belonging to either Lancefield group C or group G was made. The cultures had been isolated either sporadically from patients with serious disease or as apparent clusters from various nosocomial outbreaks. T-protein antigens were sought. So far, nine distinct serotypes have been found among the group G streptococci and seven serotypes amongst theStreptococcus equisimilis(group C) strains. Of the sixteen serotypes, four were the original T-types 7, 16, 20 and 21 described by Griffith (1934). Because of the similarities of representatives of the two groups to Lancefield group A streptococci (Griffith, 1934; Maxted & Potter, 1967) a few strains not unexpectedly carried T antigens usually seen in group A streptococci. Using this scheme it has been possible to serotype 76% ofS. equisimilisstrains of human origin and 82% of group G streptococci from human clinical material. A small collection of group C and group G streptococci of animal origin could not be serotyped with the experimental T-antisera.
Electrophoretic study of the genome of human rotaviruses from Rio de Janeiro, São Paulo and Pará, Brazil
Authors: Pereira H. G. , Azeredo Rosete S. , Leite J. P. G. , Candeias J. A. N. , Rácz Maria L. , Linhares A. C. , Gabbay Yvonne B. , Trabulsi J. R.
Published: October 2009

Human rotaviruses from the states of Rio de Janeiro, São Paulo and Pará of Brazil were analysed by RNA electrophoresis. At least some bands characteristic of rotavirus double-stranded RNA were detected in 138 (86·8%) of 159 faecal samples in which the presence of rotavirus had been demonstrated by enzyme immunoassay. Of the RNA-positi ve samples, 18 (13·0%) were classified as subgroup 1, 94 (68·1%) as subgroup 2, and 26 (18·8%) could not be classified due to absence of visible bands 10 and 11. Subgroup 2 was more frequent in the three states. All strains of subgroup 1 detected in Rio de Janeiro were associated with a single short-lived school outbreak. All strains of subgroup 1 resembled each other in electrophoretie pattern, irrespective of geographical origin, although minor differences could be detected by co-electrophoresis. Subgroup 2, on the other hand, showed a great degree of electrophoretic heterogeneity and could be divided into several sub-categories.
Distribution of immunity to pertussis in the population of England and Wales
Authors: Fine P. E. M. , Clarkson J. A.
Published: October 2009

This paper presents three different methods of estimating the number and age distribution of individuals susceptible to pertussis in England and Wales. The first approach is an extrapolation from data in the prevaccine era, the second is based upon theoretical consideration of the transmission dynamics of pertussis, and the third is a detailed cohort analysis of available notification and vaccination data. Each of these analyses suggests that the total number of people susceptible to pertussis infection in England and Wales has remained at 3–4 million for the past 40 years, despite the increase and changes in numbers vaccinated. The effect of vaccination has been to reduce the incidence of infection and disease, but not to reduce the number of susceptibles. These findings, which are consistent with ‘mass action theory’, could be tested by an appropriately designed seroepidemiological survey.
The microbiology of selected retail food products with an evaluation of viable counting methods
Authors: Greenwood M. H. , Coetzee E. F. C. , Ford B. M. , Gill P. , Hooper W. L. , Matthews S. C. W. , Patrick S. , Pether J. V. S. , Scott R. J. D.
Published: October 2009

In an inter-laboratory survey, the pour plate, surface spread, agar droplet and spiral plate methods were used in parallel with the surface drop method for enumeration of micro-organisms in foods. Good agreement was obtained between all surface methods of enumeration, but there was poor agreement between molten agar methods and the surface drop method.

A total of 1143 samples of food that were ready for consumption at the point of retail sale were examined. Eight types of food products were chosen: meat pasties, sausage rolls, real-cream slices, synthetic-cream slices, mayonnaise-based coleslaws, faggots, patés and continental sausages. The results of this survey suggest that the upper limit for an acceptable viable count should vary according to the food product. Salmonellae were not isolated on any occasion. Potentially harmful organisms were not isolated at levels expected to constitute a public health hazard.

Information concerning the nature of the product, the total viable count, the presence or absence of pathogenic, toxigenic or indicator organisms, the spectrum of the bacterial flora and the relative predominance of each organism must all be considered when assessing the microbiological acceptability of retail ‘ready to eat’ products.
Avian tuberculosis in pigs: miliary lesions in bacon pigs
Authors: Windsor R. S. , Durrant D. S. , Burn K. J. , Blackburn J. T. , Duncan W.
Published: October 2009

An outbreak of tuberculosis caused byMycobacterium aviumtype 2 is described which resulted in the total condemnation of 26 carcasses and partial condemnation of tissues and organs of a further 200 animals. Circumstantial evidence is presented that hens running in the farmyard were the source of the infection.

Examinations of the carcasses and organs of the diseased pigs suggested that the accepted pathogenesis of the disease is incorrect and a new hypothesis is presented. The problems for the meat inspector in differentiating tuberculosis from ‘milk-spot liver’ are discussed and recommendations made.

The findings of the study are discussed in the light of ‘The Meat Inspection Regulations 1963’ and it is recommended that where tuberculosis is suspected there is no longer any necessity to split the carcasses. The public health implications of this study are discussed.
Methods for the isolation ofAeromonas hydrophilaandPlesiomonas shigelloidesfrom faeces
Authors: Millership S. E. , Chattopadhyay B.
Published: October 2009

Two solid selective media, xylose deoxycholate citrate agar (XDCA) and bile salts brilliant green agar (BBG) and an enrichment broth–alkaline peptone water, were evaluated for the isolation ofAeromonas hydrophilaandPlesiomonas shigelloides. Alkaline peptone water and XDCA are useful for recovery ofAeromonasbut notPlesiomonas, whereas BBG is satisfactory for both organisms.
The distribution of specific phage types of Salmonella typhimurium in chickens in Australia
Authors: Coloe P. J. , Taplin Jennifer , Fromm W.
Published: October 2009

The distribution of specific phage types of Salmonella typhimurium within the Australian chicken industry has been studied and documented on an Australia wide and state-by-state basis. A total of 1799 strains of S. typhimurium were obtained from Australia-wide sources and phage typing categorized 1498 of these isolates into 30 distinct phage types, with the remaining 301 strains untypable. Five phage types, 6, 26, 31, 135 and 179, accounted for 76% of the total strains typed, with the remaining 24% of strains being distributed among 25 phage types.

Of the major phage types, type 31 was restricted to Victoria and Western Australia, but the other types were distributed throughout Australia.

In addition, the antibiotic resistance pattern of the various phage types was determined and only five of the 30 phage types showed appreciable levels of resistance.
Mechanisms of resistance of staphylococci grown in plasma to polymorph bactericidins
Authors: Kolawole Deboye O.
Published: October 2009

The mechanisms whereby staphylococcal strains grown in plasma assume increased resistance to polymorph bactericidins were investigated. Observations reported here showed that cultural conditions could determine the path of conversion to resistance. Staphylococcal strains and mutants lacking either free coagulase or clumping factor or both all showed enhanced resistance after 10 h incubation in plasma proteins, thus giving no clear indication that these factors were involved in the interactions. In fact, prolonged incubation in bovine serum albumin (22 h) and ordinary broth medium (24 h) also resulted in increased resistance. A distinction between staphylococcal factors interacting specifically with plasma proteins and such non-specific conversions was obtained in two different ways. Stripping of a hypothetical surface protein by treatment with trypsin or 2 M potassium bromide rendered plasma- but not 24 h-broth organisms susceptible, indicating protein coating of plasma-grown organisms. Also free coagulase-positive strains and mutants incubated in plasma for 30 min were converted while those lacking both or possessing clumping factor alone were not. It therefore appears that one of the mechanisms of acquiring resistance involves a rapid interaction between staphylococcal-free coagulase and fibrinogen, resulting in the deposition of fibrin or fibrin derivatives on the bacterial surface.
Evaluation of disinfectants in the domestic environment under ‘in use’ conditions
Authors: Scott Elizabeth , Bloomfield Sally F. , Barlow C. G.
Published: October 2009

An ‘in use’ test was developed to investigate effectiveness of disinfectant application and of detergent of hot water cleaning at kitchen, bathroom and toilet sites in the domestic environment. Detergent and hot water cleaning produced no observable reduction in microbial contamination. Single and daily application tests demonstrated that hypochlorite and phenolic disinfectants can be used to produce substantial reductions in bacterial contaminationin the home. Results indicate that maximum protection afforded by disinfection is relatively brief; 3–6 h after disinfection, contamination levels were only marginally less than those observed at pretreatment. Some suggestions are made for improvements in home hygiene.
An investigation of antigenic drift of neuraminidases of influenza A (H1N1) viruses
Authors: Luther P. , Bergmann K. Ch. , Oxford J. S.
Published: October 2009

A newly developed lectin neuraminidase test (LNT) and a panel of mouse monoclonal and post-infection ferret antibodies have been used to analyse antigenic drift in N1 neuraminidases of influenza A viruses isolated between 1933 and 1957 and also between 1977 and 1980. Significant antigenic differences were detected among the ‘early’ (1933–57) viruses since the NA of viruses isolated one year apart could be distinguished serologically. The NA ofthe ‘re-emerged’ virus A/USSR/92/77 (H1N1) was antigenically related but not identical to influenza A viruses isolated in 1949 (A/Paris/49 (H1N1), A/Geneva/49 (H1N1)) which thus predates the previously observed antigenic similarity of A/USSR/77 with A/FW/50 (H1N1) virus.
Human sera possess a limited antibody repertoire to influenza neuraminidase antigenic variants selectedin vitro
Authors: Natali Anita , Panizzi P. F. , Chezzi C. , Oxford J. S.
Published: October 2009

Four antigenic variants of the neuraminidase (NA) of A/Texas/77 (H3N2) virus were selected using monoclonal antibody at a frequency of one variant in 105parental virions. The antigenic variants failed to react serologically with the monoclonal antibody used for their selectionin vitro. The antigenic variants failed also to react serologically with a proportion of sera from children and adults although all of the sera reacted with the parental A/Texas/77 virus. Thus, certain human sera have a restricted antibody repertoire to influenza NA antigen which might enable virus antigenic variants to avoid anti-NA antibody-mediated neutralization in nature.
Tuberculosis in East Sussex: III. Comparison of post-mortem and clinical methods for the diagnosis of tuberculosis in badgers
Authors: Pritchard D. G. , Stuart F. A. , Wilesmith J. W. , Cheeseman C. L. , Brewer J. I. , Bode R. , Sayers P. E.
Published: October 2009

Following epidemiological and ecological studies of a defined badger population in an area of East Sussex, removal of all badgers by cage trapping was attempted. Trapping was incomplete due to the activities of protesters. Forty-seven badgers were caught from the eight social groups. All badgers were examined clinically and samples of faeces, urine and tracheal aspirate were taken, together with swabs from any bite wounds, for bacteriological examinations. Forty-five animals were skin tested using whole killed cells of Mycobacterium bovis strain AN5, bovine PPD Weybridge and new human tuberculin. Skin test results were recorded after 24 and 72 h. All badgers were killed and subjected to a post-mortem and bacteriological examination.

M. bovis was detected in 10 (21·3%) badgers at post-mortem and in 2 badgers from clinical samples. Four social groups were infected. Positive skin test results were recorded at 72 h with bovine PPD (2 μg and 20 μg/ml), strain AN 5 (1 mg/ml) and human tuberculin (2 μg/ml), but not with human tuberculin at 20 μg/ml. Histological sections of the skin test reactions showed the cellular types typical of delayed-type hypersensitivity. The skin test reactions observed were neither sensitive nor specific enough to be of practical value.
Recolonization and colonization resistance of the large bowel after three methods of preoperative preparation of the gastrointestinal tract for elective colorectal surgery
Authors: van den Bogaard A. E. J. M. , Weidema W. F. , van Boven C. P. A. , van der Waay D.
Published: October 2009

The impact of three current types of preoperative large bowel preparation on the microbial flora and the colonization resistance (CR) was investigated in 15 volunteers. In the first group a whole gut irrigation was performed without administration of antibiotics (group WGI). In the second group 0·5 g/1 metronidazole and 1 g/1 neomycin was added to the irrigation fluid (group WGI + AB). A whole gut irrigation with prior oral administration of 1 l mannitol 10% was performed in the third group. The antibiotic prophylaxis in this group consisted of two doses of 80 mg gentamiein i.v. and 500 mg metronidazole orally 24 h after lavage (group Mann + AB). One hour after the mechanical cleansing procedure was finished all volunteers were orally contaminated with one dose of anEscherichia colitest strain. The aerobic faccal reduction due to the cleansing procedure was 2–3 logs, while for the anaerobes it was 4–5 logs. The anaerobic flora in group WGI recovered within 24 h, while the aerobes showed a transient ‘overgrowth‘ for the period of 2 days. The overgrowth of aerobes in group WGI + AB was observed for more than a week and the total numbers of aerobes started gradually to decline after the anaerobic flora had reached pretreatment levels at day three or four. Despite the normal numbers of anaerobes present 24 h after treatment, overgrowth ofE. coliwas seen in the group Mann + AB, probably due to residual mannitol left in the intestinal tract. The test strain ofE. coliwas excreted for a period of 1 week by the volunteers in the groups WGI and Mann + AB, but it was isolated for more than 10 weeks in the group WGI + AB. It is thought that all three methods of preoperative large bowel preparation decreased the CR of the gastrointestinal tract because of a disturbance of the interaction between aerobic and anaerobic microorganisms and alterations of the colonic wall. The anaerobic microflora. however, appeared to be primarily responsible for the maintenance of the CR. Antimicrobial prophylaxis should consist of a high dose, short term. systemic antibiotic regimen, not only because an adequate serum level of an appropriate drug at the time of operation substantially decreases the incidence of postoperative septic complications but also because a systemic regimen scarcely influences the CR of the gastrointestinal tract. β-Aspartylglycine appeared to be a specific but not very sensitive marker for decreased CR.
The effect of oxygen-dependent antimicrobial systems on strains ofLegionella pneumophilaof different virulence
Authors: Jepras R. I. , Fitzgeorge R. B.
Published: October 2009

Four strains ofLegionella pneumophilaof different virulence as identified by ability to produce pneumonia and death in guinea-pigs infected by a fine-particle aerosol were examined for factors which may intracellularly influence virulence. Possible bactericidal mechanisms possessed by alveolar phagocytes were examined. A relationship could be established between resistance to H2O2, catalase activity and virulence amongst the strains.

Virulent strains resisted the bactericidal activity generated by the xanthine oxidase system; avirulent strains did not. Incorporation of various specific inhibitors of the xanthine oxidase system indicated that the main bactericidal activities were associated with the production of H2O2and hydroxyl radicals ('OH).

All strains ofL. pneumophilawere susceptible to the bactericidal activity generated by the myeloperoxidase-H202-halide system, confirming earlier observations that polymorphonuclear neutrophil leucocytes (PMNLS) are able to kill both virulent and avirulent strains ofL. pneumophila.
Serological studies on British leptospiral isolates of the Sejroe serogroup: I. The identification of British isolates of the Sejroe serogroup by the cross agglutinin absorption test
Authors: Little T. W. A. , Stevens A. E. , Hathaway S. C.
Published: October 2009

Using the cross agglutinin absorption test 12 British leptospiral isolates of the Sejroe serogroup were identified to serovar level. Six strains isolated from cattle, two from pigs and one from a human were identified as Leptospira interrogans serovar hardjo. Two isolates from wildlife were identified as Leptospira interrogans serovar saxkoebing. One further strain isolated from wildlife closely resembled serovar saxkoebing, but specific identification was not possible. These are the first reported isolations of serovar saxkoebing in the United Kingdom. The problems associated with the cross agglutinin absorption test, and possible alternative typing procedures are discussed.
Evaluation of a two-minute strep A direct swab test (SADST) on patients with pharyngitis at a primary care clinic
Authors: Araj G. F. , Majeed H. A.
Published: October 2009

A two-minute strep A direct swab test (SADST) was used to detect the presence of Lancefield group A streptococci (GAS) from the throats of 207 patients with pharyngitis at a primary-care clinic. The results were compared with a standard culture method. Fifty-one specimens were positive and 156 specimens were negative for GAS by culture. The SADST had a sensitivity of 96% (49 of 51) and specificity of 98·7% (154 of 156). The predictive values of a positive and negative SADST, for GAS, were 96% and 98·7 % respectively. The SADST showed negative reactions with five specimens containing beta-haemotytic streptococci other than GAS and 34 known stock cultures other than GAS. Our results indicate that SADST is a rapid, simple, convenient and reliable test to use for diagnosis of GAS pharyngitis at primary care clinics, physicians' offices and clinical laboratories.
The immunoglobulin M response to rubella vaccine in young adult women
Authors: Mortimer P. P. , Edwards J. M. B. , Porter A. D. , Tedder R. S. , Haslehurst J.
Published: October 2009

Rubella vaccination histories were taken from 333 young women working in the head office of a retail organization: 29% said they had had vaccine and 47% said they had not. The remainder did not know. Forty-six per cent of those ≤ 25 years old (who should have been offered vaccine at school), and 6% of those > 25 years old, said they had been vaccinated. When screened for immunity to rubella by radial haemolysis (RH) 3% had a low level of antibody (< 15 i.u./ml) and 11% had no antibody. After immunization with Cendevax the specific rubella IgM response was measured by an IgM antibody capture radioimmunassay (MACRIA). It was only detectable in the group without RH antibody, and was present in 26/31 of them. The Ig M response to Cendevax was strongest in specimens taken 20–39 days after immunization, but in 10 out of 11 cases tested was still present at around 71 days. The specific Ig M responses to Cendevax were very similar to those in women given Almevax in an earlier study, when measured in parallel tests.

Taking both vaccines together, specific Ig M was present in 35 out of 36 vaccinees without pre-existing antibody tested between 40 and 77 days post-immunization. Detection of specific IgM by MACRIA would therefore be an effective means of determining susceptibility retrospectively in rubella vaccinees found to be pregnant.
The duration of immunity in cattle following inoculation of rinderpest cell culture vaccine
Authors: Plowright W.
Published: October 2009

The duration of immunity following a single administration of rinderpest cell culture vaccine, of 90 or more monolayer passages, was studied in E. African zebu (Boran) and grade (cross-bred European) cattle. All animals were kept for periods of 6–11 years in rinderpest-free environments; groups of them (in all 23 Borans and 10 grades) were then challenged by parenteral or intranasal inoculation of virulent virus or by contact exposure to reacting cattle. Nasal excretion of virus was studied daily over the 10-to 14-day period following challenge, and simultaneous attempts were made to detect viraemia. The neutralizing antibody response was followed at 6-month intervals over the whole post-vaccination period and then daily for 10 days and at longer intervals to 3 weeks after challenge.

All 33 animals which were exposed by various routes failed to react clinically and a rinderpest viraemia was never detected. No transmission of virus from the vaccinates to susceptible in-contact controls occurred within 14 or more days, from the 20 animals which could be so tested. Clearcut serological responses to challenge were seen in six cattle (four Borans and two grades) which were challenged after 7 years or more; these reactions were all delayed to the 9th or 10th days, i.e. they were not typically ‘anamnestic’.

These results are discussed in relation to mass vaccination campaigns for the control of rinderpest and from the comparative viewpoint of measles vaccination in man.
An extended model for transfer of micro-organisms via the hands: differences between organisms and the effect of alcohol disinfection
Authors: Mackintosh C. A. , Hoffman P. N.
Published: October 2009

A model for contact transfer of micro-organisms by hand has been extended to include representatives of bacterial species responsible for a majority of hospitalacquired infections. The ability of the organisms to transfer from contaminated fabrics to hands and from hands to sterile fabrics was measured, as was their ability to survive on the skin of the hands. There were differences between the species. Staphylococcus saprophyticus transferred well to the hand but not as well from hand to fabric as the other species; it survived well on skin. Pseudomonas aeruginosa, Klebsiella aerogenes and Serratia marcescens transferred moderately well overall and also survived on the skin. These results were in contrast to those obtained with a strain of Escherichia coli and one of Streptococcus pyogenes.

The contact transfer model was used to investigate the use of small volumes of alcohol in preventing transfer via the hands. An alcohol handrub of either 0·3 ml 80% ethanol or 0·3 ml 70% isopropanol gave reductions in transfer slightly less than that of a soap and water wash. Raising the volume, and consequently the contact time, to 0·5 ml 70% isopropanol gave a 14000-fold reduction in transfer, statistically indistinguishable from that of a thorough soap and water wash (9800-fold reduction).
Meningococcal infections in Scotland 1972–82
Authors: Fallon R. J. , Brown W. M. , Lore W.
Published: October 2009

Strains ofNeisseria meningitidisisolated from patients with meningitis or septicaemia without meningitis in Scotland during the years 1972–82 have been reviewed together with details of the age, sex, disease and outcome of the patients from whom they were isolated. A total of 1185 strains were isolated, of which 927 were examined at the Meningococcal Reference Laboratory (Scotland): 19·3% were of serogroup A, 63% of group B, 9·6% of group C, 6% of W135 and 1·6% of other groups. Non-groupable strains were rare. Disease was most common in the first years of life but there was a difference in the age distribution of disease due to the different serogroups, the proportion of disease due to group B being smaller in adults than that due to other serogroups. The overall mortality in meningitis was 7·5% and in septicaemia was 20·6%, although there were differences between the rates for the various serogroups. The serogroup distribution differed in disease as opposed to meningococci isolated from carriers although group B strains were predominant in both series. Overall, approximately 15% of strains were resistant to sulphadiazine, the proportion of resistant group A strains being higher than that of other serogroups.
Antimicrobial resistance and the ecology ofEscherichia coliplasmids
Authors: Platt D. J. , Sommerville J. S. , Kraft C. A. , Timbury M. C.
Published: October 2009

Four hundred and seven clinical isolates ofEscherichia coliwere examined for the presence of plasmids. These isolates comprised 189 which were collected irrespective of antimicrobial resistance (VP) and 218 which were collected on the basis of high-level trimethoprim resistance (TPR). The VP isolates were divided into drug sensitive (VPS) and drug-resistant (VPR) subpopulations.

Plasmids were detected in 88% of VP isolates (81% of VPS and 94% of VPR) and 98% of TPR isolates. The distribution of plasmids in both groups and subpopulations was very similar. However, there were small but statistically significant differences between the plasmid distributions. These showed that more isolates in the resistant groups harboured plasmids than in the sensitive subpopulation (VPS) and that the number of plasmids carried by resistant isolates was greater. Multiple drug resistance was significantly more common among TPR isolates than the VPR subpopulation and this was paralleled by increased numbers of plasmids.

Fifty-eight per cent of VPR and 57% of TPR isolates transferred antimicrobial resistance and plasmids toE. coliK12. Of the R+isolates, 60% carried small plasmids (MW < 20Md) and 52% of these co-transferred with R-plasmids. These results are discussed.
Use of an ammonia electrode to study bacterial deamination of amino acids with special reference tod-asparagine breakdown by campylobacters
Authors: Karmali M. A. , Williams A. , Fleming P. C. , Krishnan C. , Wood M. M.
Published: October 2009

A method using an ammonia electrode is being developed for investigating the deamination of amino acids and amides by bacteria. Application of this method toCampylobacter jejuniandC. colihas led to the demonstration ofd-asparaginase activity in some strains. This has allowed the subdivision of both species intod-asparaginase-positive and -negative biotypes. Even though the method is in the developmental stage, it was found to be generally reproducible and easy to perform. Areas for further improving the procedure have been identified. The ammonia electrode offers the theoretical possibility of investigating the breakdown of any amino acid by bacteria. It thus opens up a new and practical approach for separating species and strains, particularly in those bacterial groups that are difficult to subdivide by conventional means.
Surveillance of hepatitis B virus infection in Scotland, 1973–1982
Authors: Ako T. I. , Follett E. A. C. , Dewar R. D. , Cossar J. H. , Reid D.
Published: October 2009

Since 1973 epidemiological surveillance of laboratory-confirmed hepatitis B virus infection has been undertaken in Scotland. During the ten-year period, 1973–82, 2893 persons with laboratory evidence of infection were reported and the number increased by almost threefold between the beginning and the end of this time. Males accounted for 66 % of the patients and intravenous drug abuse was the most commonly encountered risk factor. The low risk to laboratory staff is confirmed, but among National Health Service hospital staff nurses accounted for 54% of those reported.
A cryptogram for recording rotavirus strains: the Rotacode
Authors: Moosai R. B. , Alcock R. , Madeley C. R.
Published: October 2009

The RNA genome of rotaviruses consists of 11 segments in four size-classes which can be separated by polyacrylamide gel electrophoresis, although 11 separate bands are not shown by all strains. We propose a cryptogram (Rotacode) based on the relative distance of migration of adjacent bands in each size-class for coding the typical pattern of each strain of virus. This provides a shorthand for recording details of each strain and for grouping electrophoretically similar strains.

Rotacode was found to be reliable and reproducible, with identical codes being obtained for the same samples in repeated experiments under code and by various observers. Rotacode was also used to analyse 189 strains obtained over a three-year period and differentiated 13 electrophoretypes. This confirms the considerable electrophoretic variability of wild strains.
A comparison of three vaccines against respiratory syncytial virus in calves
Authors: Stott E. J. , Thomas L. H. , Taylor G. , Collins A. P. , Jebbett J. , Crouch S.
Published: October 2009

An inactivated vaccine against respiratory syncytial virus (RSV) was compared with two live vaccines. The inactivated (GC) vaccine consisted of glutaraldehyde-fixed bovine nasal mucosa cells persistently infected with RSV and emulsified with oil adjuvant. The live vaccines were a modified virus (MV) derived from a bovine strain of RSV and a temperature-sensitive mutant (ts-1) derived from a human strain. The GC vaccine was inoculated subcutaneously into 12 calves and the live vaccines intramuscularly into eight calves each. Nine unvaccinated calves acted as controls. The vaccines were administered in two doses 3 weeks apart and all calves were challenged intranasally with 2 × 107p.f.u. of bovine RSV 3 weeks after the second dose.

At the time of challenge calves given GC, MV and ts-1 vaccines had mean serum neutralizing antibody titres of 25, 19 and 2 respectively; mean titres of IgG1antibody by radioimmunoassay were log104·5, 1·3 and 2·6 respectively and mean zone areas by single radial haemolysis (SRH) were 107, 27 and 36 mm2respectively.

Eleven of 12 calves given GC vaccine were completely protected against challenge but all control animals and those given the two live vaccines were infected. The mean peak titre of virus in nasal swabs of control calves was 3.0 log10p.f.u./ml and the mean duration of virus shedding was 6·8 days. Both these parameters were significantly reduced in animals given MV and ts-1 vaccines: mean peak titres were 2·1 and 2·4 log10p.f.u./ml and mean duration of shedding was 3·4 and 3·3 days respectively.

Thus, protection correlated better with RSV antibody detected by radio-immunoassay and SRH than with neutralizing antibody. These results are discussed in relation to the possible mechanism by which protection was mediated.
Interpretation of responses and protective levels of antibody against attenuated influenza A viruses using single radial haemolysis
Authors: Al-Khayatt R. , Jennings R. , Potter C. W.
Published: October 2009

Antibody determinations against H3N2 and H1N1 type A influenza viruses were carried out on paired sera obtained from volunteers taking part in influenza virus vaccine studies, using both the haemagglutination-inhibition (HI) and single radial haemolysis (SRH) test. Good correlation between the HI and SRH test was found for both H3N2 and H1N1 antibody and the zone area increases corresponding to significant SRH antibody rises determined for both virus strains. In both H3N2 and H1N1 vaccine studies, intranasal infection of the volunteers with live attenuated viruses was involved and by the measurement of HI and SRH antibodies prior to and following infection, levels of antibody equating with protection against the infecting viruses could be estimated. For the HI test the antibody titres associated with 50% protection were 42 for H1N1, and 44 for H3N2 viruses; for the SRH test, 50% protection was associated with zone areas of 20·0–25·0 mm2for both H1N1 and H3N2 viruses.
Isolation of an English uukuvirus (family Bunyaviridae)
Authors: Eley S. M. , Nuttall P. A.
Published: October 2009

A virus of the Uukuniemi serogroup was isolated from various organs of a moribund kittiwake (Rissa tridactyla) and from ticks (Ixodes uriae) that were feeding on the bird. The kittiwake was found on Marsden beach, north-east England. This is the first virus in the family Bunyaviridae to have been isolated in England and only the second English arthropodborne virus after louping ill virus, family Togaviridae (Smith & Varma, 1981). The possibility of infection of humans by uukuviruses is discussed.
Vaccination againstKlebsiella aerogenes
Authors: Roe E. A. , Jones R. J.
Published: October 2009

Klebsiella vaccine was prepared from strains ofKlebsiella aerogeneswith capsular types Kl, K36, K44 and K Cross (a type which cross-reactsin vitrowith sera from many klebsiella capsular types). The vaccine was extracted by dialysis and ultrafiltration from capsular material released during growth of the bacteria in a five-day batch culture.

Mice given one dose of vaccine from K1a (l·0 μg/mouse) survived lethal intraperitoneal challenge of 11/11 homologous klebsiella strains four days after vaccination; 14 days after vaccination protection against the same challenge strains had declined to 5/11 strains. Vaccines from Kla, b, c, K3G, K44 and K Cross induced homologous protection and protected mice against different ranges of heterologous klebsiella capsular types.

The protective response of the mice was greatly enhanced by administering three doses of the vaccines. Vaccines from Kl, K36, K44 and K Cross protected mice against 14/20, 11/20, 10/20 and 9/20 homologous and heterologous klebsiella challenge strains respectively.

None of the klebsiella vaccines was toxic for mice at the immunizing dose (l·0 μg/mouse). Vaccine from K36 was the most lethal, killing mice at 103immunizing doses. The least toxic vaccine was from K44, which killed mice at 104immunizing doses.
The carriage of Corynebacterium suis in male pigs
Authors: Jones J. E. T. , Dagnall G. J. R.
Published: October 2009

This investigation was designed to determine the prevalence of Corynebacterium suis in the preputial diverticulum of pigs of various age groups, located in different parts of the U.K., and to demonstrate whether the organism is transmissible between male pigs.

C. suis was isolated from almost 90% of 224 adult males, distributed among 25 pig units in widely separated regions of the country and in 96 % of 66 pigs aged 5–6 months originating from six different herds in East Anglia. The rate of isolation of C. suis from younger pigs depended, at least in part, on the system of husbandry practised. Thus, in one herd, A, in which young pigs were maintained in comparative isolation, none of 26 pigs aged 5–8 weeks harboured C. suis; however, in the same herd, the organism was isolated from 77 % of 64 pigs aged 9–15 weeks which were in close contact with male pigs aged up to 6 months. In another herd, B, in which individual litters were housed in the same pen from birth to 5 months of age, C. suis was isolated once from only one of 36 pigs in the age range 5–17 weeks, sampled on two occasions, with an interval of 5 weeks between each sampling. In a third herd, C, in which adult males had never been present, C. suis was not isolated from any of 26 pigs aged 4 months.

In each of two herds at the Royal Veterinary College colonization of the preputial diverticulum by C. suis was shown to have occurred by the age of 5 weeks in all of 38 pigs examined in a Large White herd and in all of 29 pigs in a Göttingen miniature pig herd.

Transmission experiments clearly demonstrated the ease and rapidity with which the preputial diverticulum became colonized with C. suis when non-infected pigs were placed in close contact with pigs which harboured the organism.
Antibiotic resistance in Escherichia coli causing generalized infections in chickens in the UK in 1982: the relationship between the results of in vitro and in vivo furazolidone sensitivity tests
Authors: Smith H. Williams , Lovell M. A.
Published: October 2009

Compared with a similar survey conducted ten years previously, a survey conducted in 1982, eleven years after the implementation of legislation forbidding the routine use of feeds containing ‘therapeutic’ antibiotics, revealed a decreased incidence of resistance to tetracyclines, furazolidone and sulphonamides in Escherichia coli strains causing generalized infections in chickens in the UK; the decrease was particularly marked in the case of tetracycline resistance, 17·9% of strains in 1982 being resistant to this antibiotic compared with 31·2% in 1972.

Giving furazolidone to groups of chickens inoculated intramuscularly with O2:K1 strains of E. coli of differing degrees of furazolidone sensitivity indicated that great care is required in the performance and interpretation of laboratory tests for sensitivity to this antibiotic. Infections caused by strains that required as little as 1·25 μg/ml of furazolidone to inhibit their multiplication in laboratory tests responded poorly to furazolidone treatment; those that were inhibited by less responded well, better than to treatment with tetrac3rcline, chloramphenicol. ampicillin or trimethoprim.
Frequency of isolation of enterotoxigenic staphylococci from milk of nursing mothers in Kaduna, Nigeria
Authors: Adekeye J. D. , Adesiyun A. A.
Published: October 2009

Milk samples from 251 nursing mothers were screened for enterotoxigenic staphylococci. The incidence of staphylococci in milk samples was 71·3%. Two hundred and sixteen strains were isolated from 179 mothers. Eighty-six (39·8%) of the 216 strains were found to be toxigenic. Enterotoxin type A (SEA) predominated, with 41 strains (19·0%) elaborating it. Twenty-one strains (9·7%) produced enterotoxin B (SEB) while only eight (3·7%) produced enterotoxin C (SEC). Ten strains (4·6 %) produced all three types. Enterotoxigenic strains usually produced coagulase, thermonuclease and alpha haemolysin.

In this series breast-feeding alone was more common than combined breast and bottle feeding, especially among mothers less than 30 years old. The incidence of reported infantile diarrhoea decreased with increasing age of the mother. Of 16 babies with diarrhoea, 10 (62·5%) had mothers whose milk yielded staphylococci. Six of these were toxigenic. Although no direct relationship between enterotoxigenic staphylococci in the milk of nursing mothers and infantile diarrhoea could be demonstrated, these findings reveal a potential health risk to these infants.
Further observations on the excretion of salmonella in the faeces of calves fed milk substitute
Authors: Hinton M. , Suleyman I. O. , Allen Vivien , Linton A. H.
Published: October 2009

Swabs of rectal faeces were obtained daily for 28 days from 90 calves reared in five batches during the summer of 1983. The calves were purchased unweaned in markets and fed a milk-substitute diet. Salmonella typhimurium phage type DT204c was isolated from calves in four batches and Salmonella newport from one. When the data from the 90 calves were considered together the incidence of salmonellas, excretion rose to peak between 5 and 7 days after purchase before declining to low levels during the fourth week. Salmonella was isolated from 55 (61%) calves; 30 were positive on up to four occasions while 21 and 4 animals respectively were positive between 5 and 11 and 15 and 20 times. In the majority of animals infection was probably subclinical since treatment with antibacterial drugs and excretion of S. typhimurium coincided in four calves only.
Oscillatory fluctuations in the incidence of infectious disease and the impact of vaccination: time series analysis
Authors: Anderson R. M. , Grenfell B. T. , May R. M.
Published: October 2009

This paper uses the techniques of time series analysis (autocorrelation and spectral analysis) to examine oscillatory secular trends in the incidence of infectious diseases and the impact of mass vaccination programmes on these well-documented phenomena. We focus on three common childhood diseases: pertussis and mumps (using published disease-incidence data for England and Wales) and measles (using data from England and Wales, Scotland, North America and France). Our analysis indicates highly statistically significant seasonal and longer-term cycles in disease incidence in the prevaccination era. In general, the longer-term fluctuations (a 2-year period for measles, 3-year periods for pertussis and mumps) account for most of the cyclical variability in these data, particularly in the highly regular measles series for England and Wales. After vaccination, the periods of the longer-term oscillations tend to increase, an observation which corroborates theoretical predictions. Mass immunization against measles (which reduces epidemic fluctuations) magnifies the relative importance of the seasonal cycles. By contrast, we show that high levels of vaccination against whooping cough in England and Wales appear to have suppressed the annual cycle.
Development of an enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies against an H7N7 and an H3N8 equine influenza virus
Authors: Denyer M. S. , Crowther J. R. , Wardley R. C. , Burrows R.
Published: October 2009

This paper describes a solid-phase microtitre plate enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to equine influenza viruses. Using egg-grown influenza viruses as the antigens attached to the solid phase, crossreactions were observed between an H7N7 equine virus (designated A1) and an H3N8 equine influenza virus (designated A2) when untreated antisera were tested. Absorption of antisera with egg-grown A/Porcine/Shope/1/33 influenza virus eliminated cross-reactive antibodies so that specific detection of anti-equine influenza A1 or A2 antibodies was possible.

Examination of horse sera following vaccination with A1 and/or A2 isolates showed that antibodies were produced against antigen associated with egg allantoic fluid as well as against virus. Such antibodies were eliminated following the absorption of antisera with porcine influenza virus. Results using sera from horses with known vaccination histories confirmed that the ELISA preferentially detected antibodies homologous to the antigen attached to the solid phase and methods to evaluate the current serological state of individual horses by relating the titres of specific antibodies against equine influenza A1 and A2 isolates are shown. This ELISA provides a simple and rapid method of assessing specific antibodies from horse sera and offers advantages over the ‘routine’ HI and SRH assessments since it gives high precision, is economical of reagents and has the capacity to handle large numbers of serum samples.
Preliminary survey of domestic animals of the Sudan for precipitating antibodies to Rift Valley fever virus
Authors: Eisa M.
Published: October 2009

In a preliminary seroepidemiological survey a total of 780 serum samples derived from various domestic animals of the Sudan were examined for Rift Valley fever (RVF) virus precipitating antibodies. The incidence was approximately 34·3% in sheep, 33·2% in cattle, 22%in goats, 7·9% in camels and 4% in donkeys. The findings indicated that RVF is mainly prevalent in the rich savanna areas of the south as well as the irrigated areas close to the Nile in the north.

Circumstantial evidence suggests that the detected antibodies were induced by a long-standing cryptically cycling infection and that resurgence of extensive epizootics is unlikely although limited outbreaks may occur. It is concluded that RVF virus circulates across the country in a south–north range along the Nile Valley with little or no extension to the drier lands to the east and west, and that ruminants are the primary species involved in virus maintenance. These species evidently serve as main amplifiers of infection during epizootics, but whether or not they also serve as sole virus reservoirs in inter-epizootic periods has yet to be determined.