Mary Cafferkey

Group B streptococcal disease in UK and Irish infants younger than 90 days

The incidence, morbidity, and mortality of group B streptococcal disease in the UK and Republic of Ireland are largely unknown. Between Feb 1, 2000, and Feb 28, 2001, we identified cases of invasive group B streptococcal disease in infants younger than 90 days through surveillance involving paediatricians, microbiologists, and parents. 568 cases were identified, equivalent to a total incidence of 0.72 per 1000 live-births (95% CI 0.66-0.78); the incidence for early-onset disease (n=377) was 0.48 per 1000 (0.43-0.53), and for late-onset disease (n=191) was 0.24 per 1000 (0.21-0.28). Risk factors were identifiable for 218 (58%) cases of early-onset disease. 53 infants died (overall 9.7%). We have established the minimum current burden of group B streptococcal disease in UK and Irish infants. This information will assist in the formulation of guidelines for prevention of this disease.

Target Gene Sequencing To Characterize the Penicillin G Susceptibility of Neisseria meningitidis

ABSTRACT Clinical isolates of Neisseria meningitidis with reduced susceptibility to penicillin G (intermediate isolates, PenI) harbor alterations in the penA gene encoding the penicillin binding protein 2 (PBP2). A 402-bp DNA fragment in the 3′ half of penA was sequenced from a collection of 1,670 meningococcal clinical isolates from 22 countries that spanned 60 years. Phenotyping, genotyping, and the determination of MICs of penicillin G were also performed. A total of 139 different penA alleles were detected with 38 alleles that were highly related, clustered together in maximum-likelihood analysis and corresponded to the penicillin G-susceptible isolates. The remaining 101 penA alleles were highly diverse, corresponded to different genotypes or phenotypes, and accounted for 38% of isolates, but no clonal expansion was detected. Analysis of the altered alleles that were represented by at least five isolates showed high correlation with the PenI phenotype. The deduced amino acid sequence of the corresponding PBP2 comprised five amino acid residues that were always altered. This correlation was not complete for rare alleles, suggesting that other mechanisms may also be involved in conferring reduced susceptibility to penicillin. Evidence of mosaic structures through events of interspecies recombination was also detected in altered alleles. A new website was created based on the data from this work (http://neisseria.org/nm/typing/penA ). These data argue for the use of penA sequencing to identify isolates with reduced susceptibility to penicillin G and as a tool to improve typing of meningococcal isolates, as well as to analyze DNA exchange among Neisseria species.

Community study of toxoplasma antibodies in urban and rural schoolchildren aged 4 to 18 years

To estimate the prevalence of toxoplasma antibodies in schoolchildren and their association with clinical and environmental data, antibody titres were measured in 1276 children aged 4 to 18 years attending primary and secondary schools. Environmental and clinical data were obtained by questionnaire. Altogether 12.8% (163/1276) of children had antibodies to Toxoplasma gondii with no difference between the sexes. Seroprevalence was higher in country children (16.6% (50/302)) than town children (10.2% (75/737)). The proportion testing positive increased with age in both town and country children. No association with cat ownership was found. Toxoplasma seropositivity was associated with a positive toxocara titre, having had a bitch whelp in the past two years, and having an unwormed dog at home. Lack of energy or tiredness in the last 12 months were the only clinical features associated with a positive titre.

PCR-Based Assay for Detection of Neisseria meningitidis Capsular Serogroups 29E, X, and Z

ABSTRACT PCR-based assays for the identification of Neisseria meningitidis serogroups 29E, X, and Z by detection of specific regions of the ctrA gene are described. The specificities of these assays were confirmed using serogroups A, B, C, 29E, H, W135, X, Y, and Z and nongroupable meningococcal isolates.

Measles outbreak in Dublin, 2000

Background. An outbreak of measles occurred in Ireland between December 1999 and July 2000. The majority of cases were in north Dublin, the catchment area of The Children’s University Hospital (TCUH). Methods. Details of all of the 111 children attending the hospital with a diagnosis of measles between December 1999 and July 2000 were prospectively entered into a database. Charts were subsequently reviewed to extract epidemiologic and clinical details. National figures were obtained from the National Disease Surveillance Centre. Results. In the study period 355 attended TCUH with a serologic or clinical diagnosis of measles, and 111 were admitted (47% female, 53% male). The main indications for admission were dehydration in 79%, pneumonia or pneumonitis in 47% and tracheitis in 32%. Thirteen children (11.7% of those admitted) required treatment in the intensive care unit, and in 7 of these mechanical ventilation was necessary. There were 3 deaths as a result of measles. Public health measures to curb spread of the disease included promotion of immunization for susceptible children nationally and recommending administration of measles-mumps-rubella vaccine (MMR) from the age of 6 months, in North Dublin. Conclusion. This outbreak of measles posed a major challenge to the hospital and the community for the first half of 2000. The national MMR immunization rate before the outbreak was gravely suboptimal at 79%, whereas the rate in North Dublin, the catchment area of TCUH, was <70%. Three children died as a result of a vaccine-preventable illness.

Multiplex PCR for Identification of Seven Streptococcus pneumoniae Serotypes Targeted by a 7-Valent Conjugate Vaccine

ABSTRACT Here we describe a Streptococcus pneumoniae one-step multiplex PCR assay which identifies by amplicon size the seven capsular polysaccharide serotypes targeted by the 7-valent conjugate vaccine. The multiplex PCR assay was used to blindly assay clinical isolates recovered during 1999 in the Republic of Ireland from cases of invasive disease whose serotypes were previously determined by classical methods.

Consecutive use of two multiplex PCR-based assays for simultaneous identification and determination of capsular status of nine common Neisseria meningitidis serogroups associated with invasive disease.

ABSTRACT We developed two Neisseria meningitidis multiplex PCR assays to be used consecutively that allow determination of the serogroup and capsular status of serogroup A, B, C, 29E, W135, X, and Y cnl-3/cnl-1-like-containing N. meningitidis isolates by direct analysis of the amplicon size. These assays offer a rapid and simple method of serogrouping N. meningitidis.

Timing and interpretation of tests for diagnosing perinatally acquired hepatitis C virus infection.

The diagnosis of hepatitis C virus (HCV) infection in children born to HCV-infected women is based on serologic assays and HCV RNA measurement by PCR. Interpretation of the results of these tests is hampered by uncertainty about the age distribution of loss of maternal antibody and the sensitivity and specificity of PCR at different ages. On the basis of findings from a recent vertical transmission study, we estimated the posttest probability of a childs being infected or uninfected under several test result scenarios. These estimates may assist clinicians in assessing the likelihood of infection in an individual child and in using the currently available assays cost effectively.

Penicillin Susceptibility and Epidemiological Typing of Invasive Pneumococcal Isolates in the Republic of Ireland

ABSTRACT A national study was undertaken to investigate the incidence of invasive pneumococcal disease in the Republic of Ireland and to examine the associated isolates. In 1999, 144 S. pneumoniae isolates, all recovered from cases of invasive disease, were received from 12 microbiology laboratories. The incidence of invasive pneumococcal disease was estimated to be 6.6/100,000 population. All isolates were analyzed for serotype, penicillin susceptibility, chromosomal relatedness (by using pulsed-field gel electrophoresis [PFGE]), and penicillin-binding protein (pbp) fingerprinting. Several findings of note were observed regarding the pneumococcal population in Ireland. First, isolates of 25 different serotypes were represented, with serotypes 14, 9V, 8, 5, 4, and 3 being the most common. This finding, together with the pbp fingerprinting and PFGE typing results, indicated the clonal spread of strains of these serotypes in Ireland. Second, 27 (18.7%) isolates had reduced susceptibility to penicillin, and 74% of these were serotype 9V. Of these, 80% appeared to belong to the same clone. This could suggest the spread of the international Spanish/French 9V penicillin-resistant clone into Ireland. Third, nine different pbp genotypes were identified, four of which were new. Two pbp genotypes accounted for the majority of isolates dividing them according to their penicillin susceptibility status but irrespective of serotype and PFGE type. This is strong evidence for the occurrence of horizontal transfer of pbp genes between strains, observed with both penicillin-susceptible and penicillin-nonsusceptible isolates. Fourth, there was evidence of serotype transformation since isolates, indistinguishable by pbp fingerprinting and PFGE typing, expressed different capsular types.

Surgical site infection after cesarean section: implementing 3 changes to improve the quality of patient care.

BACKGROUND Surgical site infection (SSI) is an important complication of cesarean section (CS) delivery and a key quality indicator of patient care. METHODS A baseline assessment was undertaken to determine SSI rates, and subsequently a quality improvement program was introduced, followed by repeat surveillance. Data were collected during in-hospital stays and for up to 30 days after CS during both periods. Interventions in the quality improvement program included the use of nonabsorbable sutures for skin closure, use of clippers instead of razors, and use of 2% ChloraPrep for skin disinfection before incision. RESULTS A total of 710 patients were surveyed before the interventions, and 824 patients were surveyed after the interventions. Of these, 114 (16%) had an SSI before the interventions, and 40 (4.9%) had an SSI after the interventions (P < .001; odds ratio, 0.27), with 90% and 83%, respectively, detected after hospital discharge. In multivariate analysis, obesity (P = .002) and the use of absorbable suture materials for skin closure (P = .008) were significantly associated with a higher SSI rate before the interventions; however, only obesity was associated with a higher SSI rate after the quality program. CONCLUSION Surveillance of SSI rates after CS followed by 3 interventions contributed to a significant reduction in SSI rate and improved patient care.