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C A Ison

Publications and source records attributed to C A Ison.

At least 19 recordsLinked to original sources
PubMed2006

European Surveillance of Sexually Transmitted Infections (ESSTI): the first combined antimicrobial susceptibility data for Neisseria gonorrhoeae in Western Europe.

OBJECTIVES: To conduct a sentinel surveillance study for antimicrobial resistance in Neisseria gonorrhoeae in Western Europe in 2004 as part of the European Surveillance of Sexually Transmitted Infections (ESSTI) Programme. METHODS: Gonococcal isolates were collected from centres in 12 countries and transferred to two reference centres for testing. The same methodology of agar dilution was used to determine susceptibility to a range of antimicrobials used for the treatment of gonorrhoea including azithromycin, ceftriaxone, ciprofloxacin, penicillin and tetracycline. Quality control between the two laboratories was assessed during the testing. RESULTS: A total of 1055 gonococcal isolates were collected, of which 965 (91.5%) were retrievable for susceptibility testing. Resistance was found to be high to ciprofloxacin (30.9%), but also present to penicillin (21.3%) and tetracycline (59.8%). Azithromycin resistance was above 5%, the first time this has been documented in Europe. Three isolates had a low level of resistance to ceftriaxone. With regard to quality control between the two reference laboratories, 92% of MIC results were within two dilutions. CONCLUSIONS: These are the first sentinel surveillance data for Western Europe for N. gonorrhoeae and they have implications for choice of antimicrobial for treatment of gonorrhoea on a European and a local level. This is the start of the formation of a European gonococcal antimicrobial surveillance programme (EURO-GASP).

Adolescent↗
PubMed2006

Comparability of laboratory diagnosis and antimicrobial susceptibility testing of Neisseria gonorrhoeae from reference laboratories in Western Europe.

OBJECTIVES: The aim of this study was to obtain information on the comparability of methods for the laboratory diagnosis of bacterial sexually transmitted infections (STIs) that contribute to the surveillance data in the European Union (EU) and Norway. Surveillance of bacterial STIs is important across Europe because of the movement of individuals between countries at a time when STI incidence appears to be increasing in many countries. METHODS: Cross-sectional survey using a questionnaire, to provide information on laboratory methods for the diagnosis of gonorrhoea, and a panel of strains of Neisseria gonorrhoeae, to compare susceptibility testing, was circulated to laboratories in the EU and Norway. RESULTS: The questionnaire revealed marked diversity in the methodologies used for the laboratory diagnosis of gonorrhoea across Europe. Fourteen laboratories participated in an exchange of gonococcal strains to assess the methodology in current use for susceptibility testing. The methods included disc diffusion and determination of the minimum inhibitory concentration (MIC) using agar dilution and/or Etest. There was no common method used, each centre varied from another by at least one procedure. Overall agreement using all methods was >70%, being highest for ceftriaxone and lowest for tetracycline. Disc diffusion gave the lowest agreement with the consensus compared with determination of MIC by either agar dilution or Etest. CONCLUSIONS: A variety of methods were used across the EU and Norway for the laboratory diagnosis and susceptibility testing and resulted in poor concordance between laboratories on the definition of resistant N. gonorrhoeae. This suggests that there is a need for greater standardization of methodology that provides surveillance data in the EU and Norway.

Anti-Bacterial Agents↗
PubMed2006

The prevalence of proline iminopeptidase negative Neisseria gonorrhoeae throughout England and Wales.

BACKGROUND: The accurate laboratory identification of Neisseria gonorrhoeae is an essential element of the diagnosis of gonorrhoea and is particularly important for medicolegal cases. The detection of proline iminopeptidase (Pip) activity is widely used as a marker for gonococci, although Pip negative N gonorrhoeae isolates have been shown to generate false negative identifications when using biochemical kits. This study aimed to determine the frequency of Pip negative gonococci in England and Wales. METHODS: A total of 2055 isolates were collected from consecutive patients attending 26 genitourinary medicine centres as part of the Gonococcal Resistance to Antimicrobials Surveillance Programme (GRASP). Upon receipt the identity of all isolates was confirmed using N gonorrhoeae specific monoclonal antibodies and the Pip status was determined using the Gonochek II kit. RESULTS: The overall prevalence of Pip negative isolates was found to be 4.33%. Significant geographical variation was observed between isolates from centres outside London (p< or =0.001). Variation was also observed within London between the nine different clinics submitting isolates (p = 0.025). There was also a higher frequency of these isolates among men who have sex with men (p< or =0.001), which may account for geographical variations. CONCLUSION: Pip negative N gonorrhoeae isolates are a very serious cause for concern as currently all biochemical test kits available within the United Kingdom require the presence of the Pip enzyme for an unambiguous identification of this pathogen. Raising awareness of the current prevalence of Pip negative N gonorrhoeae isolates is critical for the successful control of gonorrhoea.

Aminopeptidases↗
PubMed2006

Gonorrhoea.

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Conjunctival Diseases↗
PubMed2006

Chancroid.

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Antibodies, Bacterial↗
PubMed2005

Methods employed by genitourinary medicine clinics in the United Kingdom to diagnose bacterial vaginosis.

OBJECTIVE: To determine the methods used by genitourinary medicine (GUM) clinics in the United Kingdom for the diagnosis of bacterial vaginosis (BV). METHODS: A questionnaire survey of UK GUM clinics was conducted. RESULTS: 148/221 (67%) clinics returned a questionnaire. 96/148 (64.9%) clinics reported using Amsel's criteria to diagnose BV but only 29 (30.5%) of these used all four of the composite criteria. 139/148 (93.9%) clinics used the appearance of a Gram stained vaginal smear as an aid in BV diagnosis, although a variety of scoring methods was employed. In the majority of clinics, 92/148 (62.2%), one staff discipline provided the microscopy service, in 50 (33.8%) clinics two staff disciplines provided microscopy services. The bulk of microscopy services within UK GUM clinics is provided by nurses. CONCLUSIONS: Most UK GUM clinics utilise the appearance of a Gram stained vaginal smear for the diagnosis of BV although there is little consensus at present about the type of scoring method employed. Adaptation of a uniform scoring method would have enormous benefits, including consistency and reproducibility of results and the development of quality assurance schemes for BV diagnosis on a national basis. There are important issues to be addressed regarding the initial training and ongoing support for nurses providing microscopy services within UK GUM clinics.

Bacteriological Techniques↗
PubMed2005

The epidemiology of ciprofloxacin resistant isolates of Neisseria gonorrhoeae in Scotland 2002: a comparison of phenotypic and genotypic analysis.

OBJECTIVES: To characterise all isolates with reduced susceptibility or resistance to ciprofloxacin received by the Scottish Neisseria gonorrhoeae Reference Laboratory (SNGRL) in 2002 using N gonorrhoeae multi-antigen sequence typing (NG-MAST); to compare NG-MAST with conventional typing and to describe the epidemiology of ciprofloxacin resistant gonorrhoea in Scotland in 2002. METHODS: Isolates were characterised on receipt by auxotyping and serotyping (A/S typing), and antibiotic susceptibility testing, and retrospectively by NG-MAST. Epidemiological data were requested for all isolates in the study. RESULTS: The 106 isolates were separated into more sequence types (ST) than A/S classes (44 versus 17). All isolates within a sequence type had the same serotype, were homogeneous with respect to ciprofloxacin resistance category, but were sometimes heterogeneous with respect to auxotype or plasmid borne resistance to penicillin. Combined NG-MAST and epidemiological data revealed sustained transmission of several gonococcal strains predominantly within Greater Glasgow and Lothian. Clusters of isolates were associated with transmission within the United Kingdom, whereas isolates with unique STs were associated with foreign travel (p < 0.0001). CONCLUSIONS: NG-MAST is more discriminatory than A/S typing. Ciprofloxacin resistant gonococcal isolates in Scotland are heterogeneous, with endemic spread of some strains occurring predominantly in Greater Glasgow and Lothian.

Anti-Infective Agents↗
PubMed2004

Which cephalosporin for gonorrhoea?

The recommended treatment for gonorrhoea in the United Kingdom has, until recently, included the fluoroquinolone, ciprofloxacin, which consequently was used by most genitourinary medicine clinics. In 2002 national surveillance data showed that resistance to ciprofloxacin had risen to a prevalence of 9.8% (9% in 2003), indicating that the target of >95% efficacy in first line therapy was no longer achievable. The third generation cephalosporins, ceftriaxone (intramuscular) or cefixime (oral), are the recommended alternatives, but recent audit data reveal other cephalosporins are currently being used to treat gonorrhoea, notably including cefuroxime (intramuscular or, often, oral). A pharmacodynamic analysis was undertaken to determine whether all these regimens were equally potent. Ceftriaxone, 250 (or 500) mg intramuscularly, or cefixime, 400 mg orally, were calculated to give free drug concentrations above the MIC90 for 22-50 hours post dose whereas the cefuroxime regimens being used were pharmacodynamically borderline, achieving this target for only 6.8-11.2 hours and raising the spectre that continued use may select for stepwise increases in resistance, as occurred with penicillin. We therefore underscore that ceftriaxone or cefixime should be the agents of choice to replace ciprofloxacin, as recommended in the new treatment guidelines, and that cefuroxime is a poor substitute.

Anti-Bacterial Agents↗
PubMed2003

Persistence of two genotypes of Neisseria gonorrhoeae during transmission.

Isolates of Neisseria gonorrhoeae were tested using a highly discriminatory typing method, opa typing, to examine the genetic diversity over a 2-year study period of isolates from all consecutive patients with gonorrhea attending the Genitourinary Medicine clinic in Sheffield, United Kingdom. Two opa genotypes were detected throughout the 2-year time period and comprised 41% of all strains tested. The persistence of two opa types was investigated further to determine the apparent genetic stability, by examining the ability of isolates to undergo intragenic and intergenic recombination and mutation in vitro. Intragenic recombination or mutation involving the opa genes of N. gonorrhoeae in the selected isolates was not detected, but intergenic recombination did occur. opa genes of N. gonorrhoeae in vivo appear to diversify primarily through intergenic recombination. Intergenic recombination in vivo would require the presence of a mixed gonococcal infection, in which an individual is concurrently colonized with more than one strain of N. gonorrhoeae. We propose that the level of diversity of opa genotypes in a population is linked to the degree of sexual mixing of individuals and the incidence of mixed infections of N. gonorrhoeae.

Adolescent↗
PubMed2003

Detection of mixed infection of Neisseria gonorrhoeae.

We report the first published evidence, to our knowledge, of the demonstration of the potential existence of mixed infections of Neisseria gonorrhoeae in vivo through the use of a highly discriminatory genotypic technique.

Antigens, Bacterial↗
PubMed2003

Expression of the cytolethal distending toxin in a geographically diverse collection of Haemophilus ducreyi clinical isolates.

OBJECTIVE: To screen a collection of isolates of Haemophilus ducreyi for expression of the cytolethal distending toxin (CDT). METHODS: 45 clinical isolates of H ducreyi were screened for cytotoxic activity by examining the effect of culture supernatants on Hela cells. Expression was confirmed using immunoblotting with CDT specific monoclonal antibodies and the presence of the cdt genes determined by amplification of the cdt genes in a multiplex polymerase chain assay. RESULTS: Of the 45 clinical isolates, six isolates from differing geographical origins did not demonstrate cytotoxic activity. Expression of CDT was also not detected in these six isolates using immunoblotting and the genes cdtA, cdtB, and cdtC were not amplified using PCR. The remaining isolates demonstrated cytotoxic activity, expressed the CDT proteins, and the presence of the cdt genes was confirmed. CONCLUSIONS: CDT is considered a virulence factor of H ducreyi but was found to be absent in 13% of isolates from different geographical origins.

Bacterial Toxins↗
PubMed2002

Gonorrhoea in London: usefulness of first line therapies.

OBJECTIVES: To determine the true prevalence and patterns of resistance of Neisseria gonorrhoeae to antimicrobial agents used for therapy in London. METHODS: A longitudinal study of a representative sample of isolates of N gonorrhoeae linked to demographic data of infected patients was undertaken. Isolates were collected from consecutive patients attending genitourinary medicine clinics in the North and South Thames regions of London during 3 months of each of 4 years, 1997-2000. Prevalence of plasmid mediated resistance to penicillin and chromosomally mediated resistance to penicillin and ciprofloxacin was determined by susceptibility testing. The association of antimicrobial resistance among gonococci with sexual orientation of the patient and country of acquisition of infection was determined. RESULTS: Numbers of gonococcal isolates collected over the same time period between 1997-2000 have increased by 74%. Plasmid mediated resistance to penicillin was low but has risen above 5% in 2000. Chromosomal resistance to penicillin has fallen below the 5% level but total resistance to penicillin, plasmid and chromosomally mediated, was above 5% in all 4 years. The incidence of resistance and reduced susceptibility to the alternative therapeutic choice, ciprofloxacin, is low but numbers are increasing in each year. High level resistance, to both penicillin and ciprofloxacin, has generally been found among heterosexual men and is often acquired abroad. However, there is some evidence of a change to endemic spread in 2000. CONCLUSIONS: This surveillance programme shows that the epidemiology of gonorrhoea in London is changing with increasing numbers and changing patterns of resistance. If gonorrhoea is to be controlled and targets set by the sexual health strategy are to be met, intervention with effective and appropriate antimicrobial agents is essential.

Adolescent↗
PubMed2002

Validation of a simplified grading of Gram stained vaginal smears for use in genitourinary medicine clinics.

OBJECTIVES: To validate a simplified grading scheme for Gram stained smears of vaginal fluid for the diagnosis of bacterial vaginosis (BV) against the accepted "gold" standard of Amsel's composite criteria. METHODS: Women attending genitourinary medicine (GUM) clinics, as part of a multicentre study, were diagnosed as having BV if three or more of the following criteria were present; homogeneous discharge, elevated vaginal pH, production of amines, and presence of "clue" cells. Women with less than three of the criteria were considered as normal. Simultaneously, smears were made of vaginal fluid and Gram stained and then assessed qualitatively as normal (grade I), intermediate (grade II), or consistent with BV (grade III). Two new grades were used, grade 0, epithelial cells only with no bacteria, and grade IV, Gram positive cocci only. RESULTS: BV was diagnosed in 83/162 patient visits using the composite criteria, the remainder being regarded as normal. The majority of patients with BV had a smear assessed as grade III (80/83, 96%) and the majority of normal women had a smear assessed as grade I (normal, 48/79, 61%), giving a high sensitivity (97.5%), specificity (96%), and predictive value for a positive (94.1%) and negative (96%) test, kappa index = 0.91. Smears assessed as grade II were found predominantly (12/13) among patients diagnosed as normal, with less than three of the composite criteria. Grades 0 and IV were both only found among normal women. CONCLUSION: This simplified assessment of Gram stained smears can be used as an alternative to Amsel's criteria and is more applicable for use in busy GUM clinics.

Body Fluids↗
PubMed2001

Immunogenicity of a serogroup B meningococcal vaccine against multiple Neisseria meningitidis strains in infants.

BACKGROUND: The serogroup B meningococcus is responsible for the majority of cases of meningococcal disease in temperate countries. Infants and young children <2 years of age are at greatest risk of disease. This study assessed the immunogenicity in infants of a serogroup B meningococcal outer membrane protein vaccine that has been used extensively in disease outbreaks in Cuba and several Latin American countries and shown to be efficacious in teenagers. METHOD: One hundred five healthy infants entering the routine vaccination schedule in Havana, Cuba, were given either 2 or 3 doses of the serogroup B meningococcal vaccine VA-MENGOC-BC at 3.5, 5.5 and 7.5 months of age. Immune response pre- and postvaccination was determined by the conventional serum bactericidal assay (SBA), a more sensitive novel whole blood bactericidal assay (WBA) and immunoglobulin ELISA. RESULTS: In 52 and 46% of infants >50% killing of the vaccine serogroup B strain (B:4:P1.19,15) and serogroup C strain, respectively, was demonstrated by the WBA after 2 doses of the vaccine. Serum bactericidal activity (4-fold increase in titer) was induced in only 27% against the vaccine serogroup B strain and in 14% against the serogroup C strain. The changes in WBA and SBA were mirrored by the serogroup B and C immunoglobulin ELISA. Cross-reactive immunogenicity against other (heterologous) serogroup B strains was demonstrated for one of the four further strains assessed by WBA. By age 16 to 18 months SBA, WBA and ELISA responses had declined considerably. The addition of a third dose of vaccine did not appear to significantly influence immunogenicity at 17 months of age. CONCLUSION: The serogroup B outer membrane protein vaccine VA-MENGOC-BC induces a demonstrable immune response in infants against both the serogroup B vaccine strain and against a serogroup C strain. Cross-reactive immunogenicity against other (heterologous) serogroup B strains is limited in this age group.

Age Factors↗