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K A Cartwright

Publications and source records attributed to K A Cartwright.

At least 37 records · Page 2Linked to original sources
PubMed1992

The lipooligosaccharide immunotype as a virulence determinant in Neisseria meningitidis.

We have studied the antigenic (immunotype) and physical characteristics of the lipooligosaccharide (LOS) of epidemiologically related Neisseria meningitidis case (36) and carrier (76) isolates associated with a virulent clone of meningococci (ET-5 complex). LOS immunotypes were determined by dot blotting using immunotype specific monoclonal antibodies and physical characteristics were determined from silver stained SDS-PAGE following proteinase K digestion. The genetic similarity of the different isolates was confirmed by analysis of the restriction fragment length polymorphisms. An association between LOS immunotype expression and invasive disease was found; 97% of case isolates expressed the L3,7,9 immunotype, of which 13% additionally expressed the L1,8,10 determinant. The LOS immunotypes of carrier strains were much more heterogeneous. The predominant immunotype was L1,8,10 (70%) and only 24% expressed L3,7,9 alone. Genotypically related case isolates from Norway (6) and Austria (18) expressed the L3,7,9 immunotype with similar frequency to the U.K. isolates. The combination of LOS immunotype and capsule expression appears to be related to the virulence of these meningococcal strains.

Antibodies, Bacterial↗
PubMed1992

Phylogenetic and epidemiological analysis of Neisseria meningitidis using DNA probes.

The genetic relationships between various serotypes and serogroups of meningococcal strains were investigated by restriction fragment-length polymorphism (RFLP) analysis using a number of random DNA probes and a probe containing a truncated copy of the meningococcal insertion sequence IS1106. The data were used to estimate genetic distance between all pairs of strains and to construct phylogenetic trees for meningococcal strains. B15:P1.16R strains isolated from cases of systemic meningococcal disease in two health districts with a high incidence of disease were clonal in contrast to similar strains from cases occurring in other parts of the UK. Strains from these areas, which contain a similar genomic deletion, were found to be derived from two distinct lineages within the B15:P1.16R phylogenetic group. RFLP data demonstrated that present serological typing systems for the meningococcus do not necessarily reflect true genetic relationships.

Blotting, Southern↗
PubMed1992

Identification and characterization of a novel insertion sequence, IS1106, downstream of the porA gene in B15 Neisseria meningitidis.

Examination of Neisseria meningitidis strains associated with endemic meningococcal disease demonstrated differences in the number of copies of a repetitive sequence. Characterization of a copy of this repetitive sequence present in B15 strains has revealed the presence of a novel insertion sequence (IS1106) located within a complex repetitive region downstream of the gene for the major surface antigen (porA). IS1106 has a length of 1137 bp and is flanked by 36bp inverted repeats. Two open reading frames (ORF1 and ORF2) are present in opposite strands in codon-codon register with ORF2 entirely located within ORF1. The predicted protein from ORF1 demonstrates homology with the 5A protein of IS5 (Kroger and Hobom, 1982). Strains from two independent outbreaks of B15 meningococcal disease in the UK were found to contain the same genomic deletion removing a copy of IS1106 downstream of the porA gene.

Alleles↗
PubMed1992

Salivary antibody testing in a school outbreak of hepatitis A.

During a community-wide outbreak of hepatitis A in Gloucester, UK there was a high attack rate in children attending two city primary schools and a pre-school centre sharing the same site. In September 1990, saliva specimens were collected from 478 (85%) of the 562 children. The prevalence of antibody to hepatitis A virus (anti-HAV), as determined by saliva testing, was 29.6%; highest prevalences were seen in 5-6-year-olds and in children from that area of the city at the centre of the community-wide outbreak. The proportion of immune children with a history of clinical hepatitis varied with age from 1 in 42.7 of under-5-year-olds to 1 in 4.7 of 8-10-year-olds. Six children who received prophylaxis with human normal immune globulin (HNIG) because they were household contacts of cases subsequently became infected. Since there was evidence of transmission outside the school environment it is unlikely that a policy of universal prophylaxis within the schools would have stopped the outbreak. Mass prophylaxis in school outbreaks is only likely to be effective if most transmission is occurring at school and if the target population can be clearly defined. Salivary antibody testing is a simple, practical and acceptable procedure in young children. Salivary antibody surveys in conjunction with vaccination against hepatitis A should provide a cost-effective method for control of future outbreaks.

Age Factors↗
PubMed1992

An outbreak of hepatitis A in Gloucester, UK.

During an outbreak of hepatitis A that occurred in Gloucester, UK between September 1989 and January 1991, 162 clinical cases were identified through notifications and laboratory reports, a monthly attack rate of 1.05 per 10,000 residents. The highest attack rate was seen in 5-14-year-olds. There were significant correlations between hepatitis A attack rates in the electoral wards of Gloucester and with the Jarman UPA 8 scores for the wards and with overcrowding, unemployment, under 5-year-olds and ethnic minority. The use of human normal immune globulin prophylaxis (HNIG) for household contacts was unsuccessful in ending the outbreak, partly because only one third of cases reported a household contact with recent hepatitis A. Our experience does not support the use of HNIG in stopping community-wide outbreaks of hepatitis A. Two public health campaigns were mounted during the outbreak; both were followed by a fall in the number of cases. Greater priority should be given to the implementation and evaluation of public health campaigns in future community-wide outbreaks of hepatitis A.

Adolescent↗
PubMed1991

Influenza A and meningococcal disease.

There are several anecdotal accounts of the association between outbreaks of influenza and meningococcal disease. The exceptional increase in the number of cases of meningococcal infection 2 weeks after an influenza A outbreak in England and Wales during November and December, 1989, provided an opportunity to investigate the relation between the two events. Patients with meningococcal disease in December, 1989, were more likely than age-matched controls to show serological evidence of recent influenza A infection (odds ratio 3.9, 95% Cl 1.2-13.9). The most likely explanation for the association is immune suppression induced by influenza A, though a lowering of mucosal resistance to meningococcal invasion may also be a factor. Public health authorities should be aware of the association and should be prepared to alert medical practitioners and the public to the increased risk of meningococcal disease when influenza A outbreaks occur.

Adult↗
PubMed1991

An outbreak of Legionnaires' disease in Gloucester.

Fourteen people living in or near the city of Gloucester fell ill with Legionnaires' disease caused by Legionella pneumophila serogroup (SG) 1 between 27 August and 27 October 1986. Another patient had fallen ill on 30 May. Nine of the 15 were diagnosed retrospectively during a case finding exercise. There were three deaths. Three cases of Pontiac fever were also diagnosed. The source was probably one or more wet cooling towers. Nineteen premises in the city with such towers were identified, and three just outside Gluocester. Samples from 11 of the 22 premises grew Legionella spp.; from nine of these L. pneumophila SG 1 (Pontiac) was isolated. The efficacy of regular addition of biocide in addition to hypochlorite added at the time of disinfection in inhibiting the growth of Legionella spp. was demonstrated. A survey of patients' movements during their likely incubation period showed that there was no single building that all patients had visited, but there were two areas of the city which nearly all had visited or passed through by car. A case-control study demonstrated an association with one of these areas. Cooling towers near both areas may have been sources but the evidence is insufficient to incriminate any single one. The unexpected finding of L. pneumophila SG 1 (Pontiac) in nine towers supports the hypothesis that there may have been multiple sources. Cooling towers may have been contaminated by mains water or by drift from other towers.

Adult↗
PubMed1991

Meningococcal carriage in close contacts of cases.

Between 1 October 1986 and 31 March 1987, 55 cases of meningococcal disease were identified in the South-West of England, an attack rate of 1.54 per 100,000 during the study period. Antibiotics used in the treatment of the disease successfully eliminated nasopharyngeal carriage of meningococci in 13 out of 14 cases without use of rifampicin. The overall meningococcal carriage rate in 384 close contacts was 18.2% and the carriage rate of strains indistinguishable from the associated case strain was 11.1%. The carriage rate of indistinguishable strains in household contacts (16.0%) was higher than the carriage rate in contacts living at other addresses (7.0%, P less than 0.05). A 2-day course of rifampicin successfully eradicated meningococci from 46 (98%) of 47 colonized contacts. In one third of cases groupable meningococci were isolated from at least one household contact; 92% of these isolates were of the same serogroup as the associated case strain. When a meningococcus is not isolated from a deep site in a clinical case of meningococcal disease, culture of serogroup A or C strains from nasopharyngeal swabs of the case or of household contacts is an indication that the close contact group should be offered meningococcal A + C vaccine in addition to chemoprophylaxis. The failure in this and other studies to isolate meningococci from any household contact in the majority of cases may be due either to the relative insensitivity of nasopharyngeal swabbing in detecting meningococcal carriage or to the acquisition of meningococci by most index cases from sources outside the household.

Adolescent↗
PubMed1990

Identification of a UK outbreak strain of Neisseria meningitidis with a DNA probe.

To investigate the epidemiology of meningococcal disease, a specific DNA probe pUS210 (carrying insert DNA which is repeated in the meningococcal genome) was isolated. The ability of this probe to hydridise with multiple polymorphic fragments in Southern blots was exploited to examine genetic relations within strains. Two geographically distinct foci of prolonged meningococcal disease (Gloucester and Plymouth, UK) are due to a clonal population of virulent strains that are distinct from those found elsewhere in the UK.

DNA Probes↗
PubMed1990

Congenital rubella after previous maternal immunity.

Two mothers who had asymptomatic rubella infection in pregnancy gave birth to severely affected infants. In both, the presence of preexisting antibody was well documented, although it could not be established whether it was the result of vaccine or natural infection.

Adult↗
PubMed1989

Effect of smoking on meningococcal carriage.

A case-control study was done to examine whether certain environmental or medical factors were associated with meningococcal carriage. Questionnaires were posted to 138 meningococcal carriers and their controls, and to 52 carriers of Neisseria lactamica and their controls. Carriers were matched to controls by age, sex, and area of residence. The overall response rate was 89%. There were no differences in environmental or medical factors between N lactamica carriers and their controls, nor in household crowding, housing conditions, frequency of physical exercise, or upper respiratory disorders between meningococcal carriers and their controls. Active smoking and the presence of other smokers in the household were independently associated with meningococcal carriage; the risk of carriage increased significantly with heavier smoking.

Adolescent↗
PubMed1989

The Stonehouse study: secretor status and carriage of Neisseria species.

The genetically determined inability to secrete the water-soluble glycoprotein form of the ABO blood group antigens into saliva and other body fluids is a recognized risk factor for meningococcal disease. During a community-wide investigation of a prolonged outbreak of disease due to a B15:P1.16 sulphonamide-resistant strain of Neisseria meningitidis in Stonehouse, Gloucestershire (the Stonehouse survey), the ABO blood group and secretor status of almost 5000 residents was determined. The proportion of non-secretors in the Stonehouse population was significantly higher than the proportion of non-secretors among blood donors in the South West Region and in England generally. Seven of 13 Stonehouse residents with meningococcal disease who were tested were found to be non-secretors, a high proportion. The outbreak in Stonehouse cannot be explained solely in terms of the increased proportion of non-secretors. There was no clear correlation between the proportions of non-secretors in different areas within the town and the incidence of cases of meningococcal disease. Carriers of meningococci, whether outbreak or other strains, were not more likely to be non-secretors. The reasons why non-secretors are more susceptible to meningococcal disease remain to be determined, but they do not appear to be related to carriage of meningococci.

ABO Blood-Group System↗