- Volume 10, Issue 1, 1977
Volume 10, Issue 1, 1977
- Short Articles
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Assay of Pertussis Vaccine Toxicity by a Rat-Paw-Oedema Method
More LessSUMMARYA method is described of using the production of oedema in the foot pad of rats as an index of the ability of pertussis vaccines to cause local reactions. At a suitable time after the subcutaneous injection of the vaccine into hind paw of the rat, the foot is excised and weighed. The technique is reproducible and most useful for the detection of oedema produced by pertussis-vaccine components sensitive to heating at 80°C for 30 min. Substances in pertussis vaccine that produce rat-paw oedema gave maximal reactions at 4 and 12 h. but were best differentiated 9 h after injection.
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Diagnosis of Rotavirus Infection by Cell Culture
More LessSUMMARYRotaviruses were detected by electronmicroscopy in 35 of 84 specimens of faeces from infants with diarrhoea, and in 31 by fluorescent staining of tissue cultures infected with the help of centrifugation. LLC-MK2 cells were found to be the most sensitive, although primary and secondary human-embryo-kidney and primary calf-kidney cells could also be used.
A micromodification of the tissue-culture method provides a relatively simple technique for the diagnosis of rotavirus infection, for the titration of virus infectivity and for estimating neutralising antibodies in serum.
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A Comparison of Chloramphenicol and Ampicillin as Bactericidal Agents for Haemophilus Influenzae Type B
More LessSUMMARYIn tests of bactericidal action against H. influenzae type b strains isolated from patients with meningitis, chloramphenicol was found to be far more reliable than ampicillin in dealing with large inocula, and more rapidly effective against both large and relatively small inocula. These findings provide a laboratory explanation for the somewhat better record of chloramphenicol as an agent for treatment of haemophilus meningitis.
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Synergism with Aminoglycosides of Penicillin, Ampicillin and Vancomycin Against Non-Enterococcal Group-D Streptococci and Viridans Streptococci
More LessSUMMARYThe antibiotic susceptibility of 10 strains of non-enterococcal group-D streptococci was compared with that of 20 strains of viridans streptococci. The minimal inhibitory concentrations of penicillin, ampicillin, oxacillin, nafcillin, cephalothin, vancomycin, erythro-mycin and clindamycin for the two groups of streptococci were very similar in range and median values. Both groups of streptococci were resistant to the aminoglycosides.
The effect of the combination of penicillin, ampicillin or vancomycin with streptomycin, kanamycin, gentamicin or tobramycin on the in-vitro killing of the two groups of streptococci was compared. For all the antibiotic combinations tested, synergism was demonstrated against all strains of non-enterococcal group-D streptococci after one or more of the time-intervals 6, 24 and 48 h. Some or all of the antibiotic combinations were synergistic against all strains of viridans streptococci after one or more of the same time-intervals. The other aminoglycosides (kanamycin, gentamicin and tobramycin) offered no advantage over streptomycin in synergism with penicillin, ampicillin or vancomycin against non-enterococcal group-D streptococci or viridans streptococci.
These results suggest that non-enterococcal group-D streptococcal endocarditis may be treated by the same regimen as endocarditis caused by the viridans streptococci.
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Experimental Infection of Monkeys with Herpesvirus Suis (Aujeszky’s-Disease Virus)
More LessSUMMARYMonkeys were infected intranasally with Herpesvirus suis. After an incubation period of 7 to 13 days the animals became acutely ill and rapidly died. Clinical signs included salivation, incoordination, ataxia and epileptiform convulsions, but not pruritus. Histo-pathological changes were confined to the central nervous system, and consisted of destruction of neurones with the formation of intranuclear inclusion bodies, gliosis and perivascular cuffing. Virus was isolated from the brain and spinal cord in the later stages of the illness but neutralising antibodies were not detected in serum. The distribution of lesions indicated direct spread of virus from the inoculation site along cranial nerves to the brain.
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- Articles
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Antigenic Relationship Between Human and Simian Rotaviruses
More LessSUMMARYThe simian rota virus, SA 11, and the murine rotavirus, EDIM, were investigated for antigenic relatedness to the human rotavirus, by immunoelectron-microscopy. These studies led to the recognition of two types of rotavirus antibody. One agglutinated “rough” virus particles only and was group-reactive; it appears to be widely distributed in various animal species, including human infants. The second antibody agglutinated “smooth” virus particles and was more species-specific, demonstrating only a one-way cross-reaction between the simian and human viruses; it was found only in convalescent-phase human sera and in hyperimmune rabbit sera and is probably protective.
The simian rotavirus is easy to propagate in primary cell culture and in cell lines and should prove useful for serodiagnosis of human gastroenteritis. It may be a candidate for immunoprophylaxis.
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Typing of Proteus Strains by Proticine Production and Sensitivity
More LessSUMMARYA simple, reliable and highly discriminating scheme for the bacteriocine typing of Proteus has been developed. Strains are typed on MacConkey’s agar according to their ability to produce a proticine active against one of 14 indicator strains having a single and specific proticine sensitivity and also according to their sensitivity to the different proticines of 13 proticine-producing strains. This new scheme of combined production and sensitivity typing was formulated after 250 strains of Proteus from clinical material had been examined for the production of proticines active against the 24 indicator strains of Cradock-Watson’s proticine typing scheme and for proticine activity and sensitivity towards each other. Three new types of proticinogenic strains were discovered and defined. Strains producing proticines of types 1, 2 and 3 were isolated frequently. These common proticines could be subtyped by their different actions on newly characterised indicator strains.
By means of this production/sensitivity (P/S) typing scheme, 250 Proteus strains were differentiated into 90 distinct types, whereas typing by sensitivity alone distinguished only 40 types and typing by production alone distinguished only 20 types (including subtypes).
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A New Polyvalent Pseudomonas Vaccine
More LessSUMMARYThis paper describes the preparation, chemical characterisation and immunogenic properties of a new polyvalent pseudomonas vaccine.
New cultural methods were devised which allowed a build-up of the immunogen in the cell wall of the bacteria, and mild extraction techniques were used to remove the immunogens from the cell wall of living bacteria without apparent physical or chemical change which might affect immuno-genicity.
The polyvalent vaccine comprised 16 component vaccines, each a lipid-protein-carbohydrate complex extracted from one of the 16 different serotypes of Pseudomonas aeruginosa.
Single injections into mice of each of the 16 component vaccines induced protection against several strains of homologous serotypes within 3 days of vaccination. The polyvalent vaccine induced similar protection against several strains of each of the 16 serotypes.
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Transfer of R Factors from Escherichia Coli to Salmonellas in the Rumen of Sheep
More LessSUMMARYAdult sheep were given into the rumen c. 108 cells each of donor strains of E. coli containing an R factor and prospective salmonella-recipient organisms and were maintained on a diet of lucerne chaff; the animals excreted the organisms, remained healthy, and no transfer of the R factor was detected. When the animals were starved for 48 h before inoculation, the ruminai environment was altered so that, on resumption of feeding, small numbers (c. 102−104 cells-less than one cell per ml of rumen fluid) of the introduced organisms were able to multiply and reach sufficient numbers for the transfer of R factors to occur within the rumen. One animal, given 7.8 × 103 cells of recipient S. lomita after starvation for 48 h, became a carrier of this organism. A second animal, given 4.4 × 102 cells of S. typhimurium after starvation for 48 h, developed acute, fatal salmonellosis 5 days later; at the time of death, large numbers of salmonella organisms (c. 109 cells per g) were present in the faeces; these included many (c. 106 cells per g) that had received the R factor by transfer in vivo. These results indicate that short periods of starvation may enhance the transfer of R factors and possibly other plasmids between suitable micro-organisms in vivo, and may increase the susceptibility of animals to pathogenic micro-organisms.
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The Survival of Gonococci and Meningococci in Subcutaneous Diffusion Chambers in Mice
More LessSUMMARYStudies are reported on the survival of gonococci and meningococci in Millipore diffusion chambers implanted subcutaneously in normal mice and in pre-immunised mice. The chambers allowed the passage of nutrients and humoral factors but excluded host cells.
After an initial fall in the viable count -attributed to lysis by non-specific serum factors-there was evidence of multiplication of Neisseria gonorrhoeae; the subsequent development of specific antibody led to the disappearance of gonococci 16 days after the chambers were implanted.
N. meningitidis behaved differently in the implanted chambers. Meningococci did not appear to be lysed by non-specific humoral factors and so the viable count showed no initial fall. The meningococci survived for 49 days, at which time the entire chamber was rejected.
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Small Virus Particles in Faeces of Patients with Infectious Hepatitis (Hepatitis A)
More LessSUMMARYForty-one faecal samples from infectious-hepatitis patients and their contacts were investigated for the presence of hepatitis-A-associated viral particles. Of these, 16 gave a positive result by immune electronmicroscopy or caesium-chloride density-gradient centrifugation. The latter method proved invaluable in detecting small numbers of virus particles. The particles found had a buoyant density of 1.34−1.35 and a size range of 21-28 nm. Epidemio-logical evidence suggested that they might be the causative agent of hepatitis A.
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The Anaerobic Culture of Clinical Specimens: A 14-Month Study
More LessSUMMARYThis paper presents the results of the examination of routine clinical specimens for anaerobes and gives details of the revised anaerobic culture techniques recently introduced into this laboratory. The species of anaerobic bacteria isolated from lesions in different sites of the body are described and recommendations are made concerning methods of identification and culture.
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Airborne Infection with Mycobacterium Leprae in Mice
More LessSUMMARYAlthough the portal of entry and mode of spread of M. leprae in human leprosy are still uncertain, it is widely held that direct person-to-person skin contact is important. This assumption has ignored the fact that patients with highly bacilliferous leprosy have nasal as well as dermal infection and that, since M. leprae is shed predominantly from the nose, leprosy might be an airborne infection. The present study was designed to investigate this possibility with mice exposed to airborne infection with M. leprae. The conditions are described in which thymectomised-irradiated CBA strain mice exposed to M. leprae aerosols sustained an immediate lung retention of 1 × 105 bacteria. Fourteen to 24 months later, 33% (10 of 30) of the mice had countable numbers of acid-fast bacilli (>2 × l04) with the characteristics of M. leprae in one or more homogenates prepared from ears, foot pads, nose or lungs. Evidence is presented from the distribution of M. leprae that the infection had arisen from systemic spread of bacilli initially entering the lungs rather than from multiplication of organisms locally retained there, or in the nose, at the time of airborne infection. The relevance of these results to the possible route of infection of leprosy in man is discussed.
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The Isolation of Streptococcus Pyogenes from Throat Swabs
More LessSUMMARYSimulated throat swabs were prepared with known numbers of Streptococcus pyogenes; some were suspended in pasteurised human saliva and an equal number in saline. Two types of commercially available swabs were tested; these were composed of (1) plain, buffered, cotton wool, and (2) albumen-coated cotton wool.
The mean recovery rates of first platings on solid media from albumen-coated and plain cotton-wool swabs were similar (8.2% and 8.3%) and the mean recovery rates from platings 1-4 were also similar (6.6% and 6.5%).
The greater the delay in plating, the less were the chances of recovery of streptococci, although the viability of these was significantly prolonged on swabs held at 4°C. Similar results were again produced by both types of swabs; processing swabs in saliva, however, produced a recovery rate that was 1-2% greater than the rate for the saline series.
Swabs were also agitated or squeezed by forceps in nutrient broth to release any organisms they contained, and standard samples of the broth were then plated on solid media. Counts thus obtained indicated that about 50% of the original inoculum was still viable and could be recovered from the broth; in comparison, recoveries from initial direct plating of the swabs were low. No demonstrable toxic effect was produced by the cotton wool in these experiments.
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Evaluation Of Methods for the Determination of O and K Antigens of an O2:K1(L) Strain of Escherichia Coli
J. R. Deb and E. G. HarrySUMMARYTests made on ten colonies from a strain of Escherichia coli 02:K1 demonstrated that bacterial agglutination tests were reliable for identifying the O antigen of serogroup 02 but were unreliable for identifying the Kl antigen. The granular nature of K agglutination was not a reliable characteristic of the L type of K antigen. In contrast, indirect haemagglutination, immunodiffusion and immunoelectrophoresis tests with bacterial extracts gave consistent results with all colonies. The polysaccharide Kl antigen formed a long anodic precipitation line with two peaks, indicating its heterogenous nature, and partial fusion of this line with the O-antigen precipitation line suggested the presence of common serological determinants. In addition, a heat-labile protein antigen, possibly another K antigen, was identified by indirect haemagglutination tests and may have produced a short anodic precipitation line. The results also showed that the Kl antigen was still produced after storage of a culture for 12 years on Dorset-egg medium.
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Sodium Aurothiomalate, Gold Keratinate, and Various Tetracyclines in Mycoplasma-Induced Arthritis of Rodents
More LessSUMMARYSodium aurothiomalate (ATM), gold keratinate and five different tetra-cyclines were investigated for activity against M. arthritidis strain ATCC 14124 and M. pulmonis strain JB, both in vitro and in rodents with arthritis caused by these mycoplasmas. In vitro, ATM had only slight activity against M. arthritidis and M. pulmonis, while gold keratinate was virtually inactive against M. pulmonis. In contrast, the tetracyclines were highly active against both mycoplasmas. The tetracyclines and the gold salts were both predominantly mycoplasmastatic.
In both rats and mice, parenteral administration of ATM, begun shortly before or after infection of the rodents with mycoplasmas, prevented the development of arthritis. ATM or gold keratinate, given subcutaneously to mice already arthritic from infection with M. pulmonis, reduced the severity of the arthritis, even although gold keratinate was inactive against this mycoplasma in vitro. Moreover, direct testing of serum, collected from mice treated with gold keratinate, failed to demonstrate antimycoplasmal activity in vitro. These results suggest that the action of gold-containing drugs in mycoplasmal arthritis is due to biological properties of gold other than antimycoplasmal activity.
Tetracyclines were also found to be effective in preventing arthritis in rats and mice when given subcutaneously. With high doses, subcutaneous, but not oral, therapy significantly reduced the severity of established arthritis in mice infected with M. pulmonis. The blood levels achieved with the different tetracyclines, when related to their therapeutic activity, indicated that good antimycoplasmal activity and adequate absorption from the gut were not the only properties needed for optimal effectiveness. The results are discussed in relation to treatment of rheumatoid patients with tetracycline HC1.
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Epidemiology of Group-B Streptococcal Carriage in Pregnant Women and Newborn Infants
More LessSUMMARYIn a population of pregnant women, the prevalence of group-B streptococcal carriage was relatively low. During the 3rd trimester of pregnancy 5.6% of women haboured group-B streptococci and 8.3% were positive at the onset of labour. Some 42% of women who gave positive cultures in labour had given negative cultures during the 3rd trimester and 19% of women who were positive during late pregnancy were culture-negative in labour. The conversion of culture status observed in these women suggests that carriage may be intermittent or that new acquisition of genital-tract streptococci may occur in late pregnancy. The unpredictability of conversion diminishes the reliability of a single culture taken during the 3rd trimester of pregnancy.
Acquisition of streptococci was seen in nearly 50% of infants born to women who were culture positive in labour. The maternal site of carriage (cervix or vagina or both) did not appear to influence the likelihood of bacterial acquisition by the infants. The isolation of streptococci from multiple sites was quite common in the infants, and the intensity of bacterial contamination was usually high. The external ear canal was a favourable site for detecting neonatal contamination with group-B streptococci; 94% of infants, who gave positive cultures at birth had positive ear-canal cultures, and in 26% the ear canal was the only site from which streptococci were isolated. This suggests that bacterial contamination of amniotic fluid by the ascending route was a common event in culture-positive women. Three infants apparently had asymptomatic streptococcal bacteriaemia.
Isolation of the same serotype of group-B streptococcus from the infants and their mothers, and the presence of the organism in the infants-often in large numbers-shortly after birth, support the view that the organism is usually transmitted from the maternal genital tract to the infant.
There was no evidence that any one type was more likely than others to be transmitted from mother to infant. Group-B streptococci of serotypes Ic, II, and III were the predominant ones in the infants and their mothers in this study.
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- Obituary Notice
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- Books Received
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Volumes and issues
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Volume 73 (2024)
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Volume 72 (2023 - 2024)
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Volume 71 (2022)
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Volume 68 (2019)
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Volume 67 (2018)
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Volume 65 (2016)
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Volume 64 (2015)
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Volume 63 (2014)
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Volume 60 (2011)
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Volume 36 (1992)
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Volume 34 (1991)
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Volume 33 (1990)
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Volume 14 (1981)
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Volume 10 (1977)
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Volume 7 (1974)
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Volume 6 (1973)
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Volume 4 (1971)
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Volume 1 (1968)