Noninvasive pneumococcal clones associated with antimicrobial nonsusceptibility isolated from children in the era of conjugate vaccines.

Carriage and noninvasive pneumococcal isolates frequently have a higher prevalence of antimicrobial nonsusceptibility than invasive isolates. From 2009 to 2014, we determined the associated clones in 169 pediatric noninvasive nonsusceptible pneumococci from a total of 506 isolates collected after 7- and 13-valent conjugate vaccine introduction (PCV7/13) to the Irish childhood immunization schedule in 2008 and 2010, respectively. We compared our results to those from 25 noninvasive pediatric pneumococcal isolates collected in 2007, the year before introduction of conjugate vaccines. In 2007, England(14)-9 and Spain(9V)-3 accounted for 12% and 32% of nonsusceptible clones, respectively, but in 2009 to 2014, their prevalence fell to 0% and 2.4%. Furthermore, there was a significant decline in Spain(6B)-2 and its variants from 2009 to 2014 (P = 0.0024). Fluctuations occurred in clonal complex 320 associated with serotype 19A. The prevalence of Sweden(15A)-25 and its variants and ST558 (a single-locus variant of Utah(35B)-24) associated with nonvaccine serotypes (NVT) 15A and 35B increased from 0% and 8% in 2007 to 19% and 16% in 2013 to 2014, respectively. Pilus locus 1 (PI-1) is associated with the spread of some nonsusceptible pneumococcal clones. PI-1 was more frequently associated with PCV7/13 serotypes than NVT (P = 0.0020). Our data highlight the value of surveillance of noninvasive pneumococci following conjugate vaccine introduction. Importantly, emerging clones associated with NVT may limit the effectiveness of PCV7/13 in reducing the high rate of nonsusceptibility among pediatric noninvasive pneumococci, with implications for empirical treatment strategies.

Molecular epidemiology of group B streptococci in Ireland reveals a diverse population with evidence of capsular switching.

The molecular epidemiology of group B Streptococcus (GBS) in Ireland was investigated. Invasive (n = 132) and non-invasive (n = 45) isolates, collected in 2007-2011, were analysed by multilocus locus sequence typing, capsular polysaccharide (CPS) serotyping, profiling of surface proteins, pilus islands (PI), and antimicrobial susceptibility. Isolates grouped into 45 sequence types and five main clonal complexes (CC). CC1, CC17 and CC23 represented 67.2 % of isolates and the most prevalent serotypes Ia, III and V. Serotype and surface protein genes were largely predictive of CC. Accordingly, CPS V/alp3, CPS Ib/CPS II/bca + bac, and CPS Ia/eps predominated in CC1, CC12 and CC23, respectively, and CPS III/rib in CC17 and CC19. Supporting their vaccine potential, all isolates harboured at least one PI, of which the PI-1 + PI-2a combination was most prevalent. Macrolide resistance was found in 18.6 % of isolates. erm(B) and the globally disseminated CC1/CPS V were the most common resistance mechanism and CC/CPS type, respectively. CC17, significantly associated with neonatal disease, was also prevalent in pregnant adults, but was underrepresented among non-pregnant adults. Two of 46 CC17 isolates (typically CPS III) were CPS IV. Sequence analysis confirmed capsular switching and their relatedness to CC17/CPS IV strains recently characterized in France. CPS IV, detected only in invasive isolates (6.8 %), was most prevalent in adults (12 %) and showed an increase in prevalence to that reported (1.4 %) for invasive isolates in Ireland 1997-1999. Increases in serotype IV and evidence of capsular switching in CC17 highlights the importance of ongoing surveillance of GBS and may have implications for vaccine development strategies.

Diversity of meningococci associated with invasive meningococcal disease in the Republic of Ireland over a 19 year period, 1996-2015.

This study examined the capsular phenotype and genotype of invasive meningococcal disease (IMD)-associated Neisseria meningitidis recovered in the Republic of Ireland (RoI) between 1996 and 2015. This time period encompasses both pre- (when IMD was hyperendemic in the RoI) and post- meningococcal serogroup C conjugate (MCC) vaccine introduction. In total, 1327 isolates representing over one-third of all laboratory-confirmed cases of IMD diagnosed each epidemiological year (EY), were characterised. Serogroups B (menB) and C (menC) predominated throughout, although their relative abundance changed; with an initial increase in the proportion of menC in the late 1990s followed by their dramatic reduction post-MCC vaccine implementation and a concomitant dominance of menB, despite an overall decline in IMD incidence. While the increase in menC was associated with expansion of specific clonal-complexes (cc), cc11 and cc8; the dominance of menB was not. There was considerable variation in menB-associated cc with declines in cc41/44 and cc32, and increases in cc269 and cc461, contributing to a significant increase in the clonal diversity of menB isolates over the study. This increase in diversity was also displayed among the serosubtyping data, with significant declines in proportions of menB isolates expressing p1.4 and p1.15 antigens. These data highlight the changing diversity of IMD-associated meningococci since 1996 in the RoI and emphasise the need for on-going surveillance particularly in view of the recent introduction of a menB vaccine.

Targeting points for further intervention: a review of HIV-infected infants born in ireland in the 7 years following introduction of antenatal screening.

Even in countries with well-developed programs for prevention of mother-to-child transmission (MTCT) of HIV, there remains a low level of ongoing transmission. Pregnant, HIV-infected women may not always access screening and available interventions because of circumstances, beliefs, and other influences. Missed opportunities for the prevention of MTCT remains an issue to be addressed. Through a review of HIV-infected children born during the years of antenatal screening in Ireland, we sought to identify further targets for intervention to further reduce MTCT.

Clinical Characteristics and Risk Factors for Poor Outcome in Infants Less Than 90 Days of Age With Bacterial Meningitis in the United Kingdom and Ireland.

BACKGROUND: To describe the clinical characteristics and risk factors associated with poor outcome in infants <90 days of age with bacterial meningitis. METHODS: Prospective, enhanced, national population-based active surveillance for infants <90 days of age with bacterial meningitis in the United Kingdom and Ireland between July 2010 and July 2011. Infants were identified through the British Paediatric Surveillance Unit, laboratory surveillance and meningitis charities. RESULTS: Clinical details was available for 263 of 298 (88%) infants where a bacterium was identified, 184 (70%) were born at term. Fever was reported in 143 (54%), seizures in 73 (28%), bulging fontanelle in 58 (22%), coma in 15 (6%) and neck stiffness in 7 (3%). Twenty-three (9%) died and 56/240 (23%) of the survivors had serious central nervous system complications at discharge. Temperature instability [odds ratio (OR), 2.99; 95% confidence interval (CI): 1.21-7.41], seizures (OR, 7.06; 95% CI: 2.80-17.81), cerebrospinal fluid protein greater than the median concentration (2275 mg/dL; OR, 2.62; 95% CI: 1.13-6.10) and pneumococcal meningitis (OR, 4.83; 95% CI: 1.33-17.58) were independently associated with serious central nervous system complications while prematurity (OR, 5.84; 95% CI: 2.02-16.85), low birthweight (OR, 8.48; 95% CI: 2.60-27.69), coma at presentation (OR, 31.85; 95% CI: 8.46-119.81) and pneumococcal meningitis (OR, 4.62; 95% CI: 1.19-17.91) were independently associated with death. CONCLUSIONS: The classic features of meningitis were uncommon. The presentation in young infants is often nonspecific, and only half of cases presented with fever. A number of clinical and laboratory factors were associated with poor outcomes; further research is required to determine how knowledge of these risk factors might improve clinical management and outcomes.

Should hepatitis B vaccination be introduced into childhood immunisation programmes in northern Europe?

Infection with hepatitis B causes between 500,000 and 1.2 million deaths per year worldwide, and is the leading cause of liver cancer. Over 12 years ago, WHO recommended that universal childhood hepatitis B vaccination be implemented globally. Despite this, Denmark, Finland, Iceland, Ireland, the Netherlands, Norway, Sweden, and the UK have yet to implement such a policy and instead currently adopt an "at-risk" strategy. Although all eight countries are classed as having low endemicity, factors such as increased travel and integration of immigrant communities are increasing the number of at-risk individuals in these countries. Considering the difficulty in identifying all at-risk individuals, and the lack of effectiveness of at-risk vaccination on reducing the overall incidence of hepatitis B, we recommend that these countries reassess their hepatitis B prevention strategies. Universal vaccination against hepatitis B is the only way to eliminate the major public-health impact of this disease.

Invasive meningococcal disease in children in Ireland, 2001-2011.

BACKGROUND: In 1999, invasive meningococcal disease was hyperendemic in Ireland at 14.75/100 000 population, with 60% group B and 30% group C diseases. National sepsis guidelines and meningococcal C vaccines were introduced in 2000. Despite a spontaneous decline in group B infection, invasive meningococcal disease remains a leading cause of sepsis. This study characterises the epidemiology of invasive meningococcal disease in children in Ireland since the introduction of meningococcal C vaccine and reviews its clinical presentation, hospital course and outcome in anticipation of meningococcal B vaccine introduction. METHODS: National surveillance data were obtained from the Health Protection Surveillance Centre. A retrospective study of all meningococcal cases at two tertiary paediatric hospitals was conducted from 2001 to 2011. Records were reviewed using a standardised assessment tool. A study of 407 meningococcal cases published in 2002 provided comparative data. RESULTS: Of 1820 cases <19 years of age notified nationally, 382 (21%) cases attended a study hospital; 94% group B, 3% group C, 225 (59%) male, median age 5 years (range 0.1-18). Fever was absent at presentation in 18%. Fifteen patients (3.6%) died. 221 (61%) were admitted to paediatric intensive care units (PICU). Permanent sequelae occurred in 9.4%. Compared with the historical cohort, there were differences in presentation, an increase in PICU interventions, but no significant decline in morbidity or mortality. CONCLUSIONS: Despite the meningococcal C vaccination campaign, invasive meningococcal disease continues to cause serious morbidity and claim lives. Group B infections remain dominant. As children who die often present with fulminant disease, preventive strategies including use of meningococcal B vaccine are needed to avert death and sequelae.

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.

Influence of serogroup on the presentation, course, and outcome of invasive meningococcal disease in children in the Republic of Ireland, 1995-2000.

To test the hypothesis that the infecting meningococcal serogroup modulates the presentation, course, and outcome of invasive meningococcal disease (IMD), we performed a retrospective review of cases of IMD in 407 children from 2 tertiary referral centers and 2 regional centers in Ireland. Patients infected with serogroup C meningococci (n=104) were older than those infected with serogroup B (n=303; median, 2.5 vs. 1.5 years; P=.04); all other demographic and clinical parameters were similar for the 2 groups. Among serogroup B patients, mortality was 3.6% and morbidity was 10%; for serogroup C patients, mortality was 4.8% and morbidity was 12.5% (P=.81 and P=.76, respectively). Serogroup C-associated sequelae more often were multiple (P=.003). Despite the introduction of serogroup C conjugate vaccine into the routine immunization schedule of some countries, ongoing morbidity from IMD is anticipated, because group B disease was very similar to group C disease in this pediatric population.

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.

Multilocus restriction typing: a tool for Neisseria meningitidis strain discrimination.

Invasive disease-associated strains of Neisseria meningitidis were analysed by multilocus restriction typing (MLRT), which involves the restriction fragment-length polymorphism analysis of PCR products generated from the seven loci of housekeeping genes used in MLST. Several different restriction patterns (alleles) were observed for each of the seven loci examined. Greater allelic variation was observed with the fumC and pgm loci than with the abcZ and adk loci, suggesting that the latter were more conserved. The alleles at each of the seven loci were combined to give an allelic profile or restriction type (RT). A good correlation between RT and serogroup, serotype and serosubtype was observed, as all C 2ap1.2,5 strains were contained in a single RT, as were all but one strain of B 4p1.4. In this study, MLRT proved to be an efficient, effective and relatively inexpensive method for N. meningitidis strain characterization.

Non-invasive pneumococcal serotypes and antimicrobial susceptibilities in a paediatric hospital in the era of conjugate vaccines.

To evaluate the effects of 7-valent pneumococcal conjugate vaccine (PCV7) introduction to the routine childhood immunisation schedule in 2008 and its replacement by PCV13 in 2010 in Ireland, we surveyed the serotypes and antimicrobial susceptibilities of 339 pneumococci associated with carriage and non-invasive infection (NII) in a Dublin paediatric hospital from 2009 to 2012. Furthermore, we compared the distribution of pneumococcal serotypes collected from 2009 to 2012 to 105 NII pneumococci isolated in 2007, the year before conjugate vaccine introduction. PCV7 serotypes declined from 2007 to 2012 as follows: carriage, 67-23% (p=0.0004); conjunctivitis, 58-0% (p<0.0001); non-bacteraemic lower respiratory tract infection, 50-19% (p=0.0363) and otitis media 54-27%. Notably, antimicrobial resistant (AMR) PCV7 serotypes showed a significant decrease by the end of the study period (i.e. 2012) (p<0.0001). Compared with 2007 the overall occurrence of serotype 19A increased from 1.9 to 10% in 2010 (p=0.0132) and to 15% in 2011 (p=0.0005). Importantly, serotype 19A declined significantly from 2011 levels to an overall prevalence of 4.8% in 2012 (p=0.0243). Most striking was the significant reduction of AMR 19A (p=0.0195). Conversely, increases were observed in non-vaccine type (NVT) pneumococci in 2009-2012, of which serotypes 11A (n=30), 15B/C (n=17), 22F (n=14), 35Bn=13), non-typeable pneumococci (n=13) and 23A (n=12) were the most prevalent. Moreover, an increase in NVT non-susceptible to at least one antimicrobial in 2009-2012 was noted, attributable to serotypes 35B (n=10) and 15A (n=7). In summary, this study has shown that PCV7 and PCV13 introduction has had a positive impact on their target serotypes and antimicrobial resistance amongst pneumococci within a paediatric hospital within a short time period. However, the increase in NVT prevalence highlights the need for continued surveillance.

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.

Development of a diagnostic real-time polymerase chain reaction assay for the detection of invasive Haemophilus influenzae in clinical samples.

Since the introduction of the Haemophilus influenzae serotype b vaccine, invasive H. influenzae disease has become dominated by nontypeable (NT) strains. Several widely used molecular diagnostic methods have been shown to lack sensitivity or specificity in the detection of some of these strains. Novel real-time assays targeting the fucK, licA, and ompP2 genes were developed and evaluated. The fucK assay detected all strains of H. influenzae tested (n = 116) and had an analytical sensitivity of 10 genome copies/polymerase chain reaction (PCR). This assay detected both serotype b and NT H. influenzae in 12 previously positive specimens (culture and/or bexA PCR) and also detected H. influenzae in a further 5 of 883 culture-negative blood and cerebrospinal fluid (CSF) samples. The fucK assay has excellent potential as a diagnostic test for detection of typeable and nontypeable strains of invasive H. influenzae in clinical samples of blood and CSF.

The impact of meningococcal polymerase chain reaction testing on laboratory confirmation of invasive meningococcal disease.

Laboratory methods of diagnosis were examined for 266 children with invasive meningococcal disease. Seventy-five (36%) of 207 cases with bloodstream infection had both positive blood culture and blood meningococcal polymerase chain reaction (PCR), 130 (63%) negative blood culture and positive blood PCR, and 2 (1%) had positive blood culture and negative blood PCR. Sixty-three percent of cases were diagnosed by PCR alone.

Target gene sequencing to characterize the penicillin G susceptibility of Neisseria meningitidis.

Clinical isolates of Neisseria meningitidis with reduced susceptibility to penicillin G (intermediate isolates, Pen(I)) 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 Pen(I) 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.

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.

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.

Multiplex PCR for identification of seven Streptococcus pneumoniae serotypes targeted by a 7-valent conjugate vaccine.

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.

Interlaboratory comparison of PCR-based identification and genogrouping of Neisseria meningitidis.

Twenty clinical samples (18 cerebrospinal fluid samples and 2 articular fluid samples) were sent to 11 meningococcus reference centers located in 11 different countries. Ten of these laboratories are participating in the EU-MenNet program (a European Union-funded program) and are members of the European Monitoring Group on Meningococci. The remaining laboratory was located in Burkina Faso. Neisseria meningitidis was sought by detecting several meningococcus-specific genes (crgA, ctrA, 16S rRNA, and porA). The PCR-based nonculture method for the detection of N. meningitidis gave similar results between participants with a mean sensitivity and specificity of 89.7 and 92.7%, respectively. Most of the laboratories also performed genogrouping assays (siaD and mynB/sacC). The performance of genogrouping was more variable between laboratories, with a mean sensitivity of 72.7%. Genogroup B gave the best correlation between participants, as all laboratories routinely perform this PCR. The results for genogroups A and W135 were less similar between the eight participating laboratories that performed these PCRs.

PCR and restriction endonuclease assay for detection of a novel mutation associated with sulfonamide resistance in Neisseria meningitidis.

We identified a previously undocumented mutation in the dihydropteroate synthase (folP) gene associated with Neisseria meningitidis sulfonamide resistance. A PCR-based assay to detect this mutation, which is 100% predictive of sulfonamide resistance, was developed.