Invasive Neonatal Disease Research Articles

Group B Streptococcal Neonatal Meningitis.

Neonatal bacterial meningitis is a devastating disease, associated with high mortality and neurological disability, in both developed and developing countries. Streptococcus agalactiae, commonly referred to as group B Streptococcus (GBS), remains the most common bacterial cause of meningitis among infants younger than 90 days. Maternal colonization with GBS in the gastrointestinal and/or genitourinary tracts is the primary risk factor for neonatal invasive disease. Despite prophylactic intrapartum antibiotic administration to colonized women and improved neonatal intensive care, the incidence and morbidity associated with GBS meningitis have not declined since the 1970s. Among meningitis survivors, a significant number suffer from complex neurological or neuropsychiatric sequelae, implying that the pathophysiology and pathogenic mechanisms leading to brain injury and devastating outcomes are not yet fully understood. It is imperative to develop new therapeutic and neuroprotective approaches aiming at protecting the developing brain. In this review, we provide updated clinical information regarding the understanding of neonatal GBS meningitis, including epidemiology, diagnosis, management, and human evidence of the disease's underlying mechanisms. Finally, we explore the experimental models used to study GBS meningitis and discuss their clinical and physiologic relevance to the complexities of human disease.

Virulence Factors of Invasive Group B Streptococcus Isolates Obtained from Pregnant Women and Neonates

Streptococcus agalactiae, or group B streptococcus (GBS), is an important pathogen for pregnant women and neonates, which can cause preterm birth, stillbirth, maternal sepsis and neonatal invasive disease. GBS are highly heterogeneous in their virulence factor expression and thus can exist as commensal bacteria or become highly invasive. In the U.S., universal screening for GBS is performed at 37-38 weeks gestation and women testing positive are treated with intrapartum antibiotic prophylaxis to prevent neonatal invasive disease.

Look Who's Talking: Host and Pathogen Drivers of Staphylococcus epidermidis Virulence in Neonatal Sepsis.

Preterm infants are at increased risk for invasive neonatal bacterial infections. S. epidermidis, a ubiquitous skin commensal, is a major cause of late-onset neonatal sepsis, particularly in high-resource settings. The vulnerability of preterm infants to serious bacterial infections is commonly attributed to their distinct and developing immune system. While developmentally immature immune defences play a large role in facilitating bacterial invasion, this fails to explain why only a subset of infants develop infections with low-virulence organisms when exposed to similar risk factors in the neonatal ICU. Experimental research has explored potential virulence mechanisms contributing to the pathogenic shift of commensal S. epidermidis strains. Furthermore, comparative genomics studies have yielded insights into the emergence and spread of nosocomial S. epidermidis strains, and their genetic and functional characteristics implicated in invasive disease in neonates. These studies have highlighted the multifactorial nature of S. epidermidis traits relating to pathogenicity and commensalism. In this review, we discuss the known host and pathogen drivers of S. epidermidis virulence in neonatal sepsis and provide future perspectives to close the gap in our understanding of S. epidermidis as a cause of neonatal morbidity and mortality.

Whole-genome sequencing-based phylogeny, antibiotic resistance, and invasive phenotype of Escherichia coli strains colonizing the cervix of women in preterm labor

BackgroundEscherichia coli is a major neonatal pathogen and the leading cause of early-onset sepsis in preterm newborns. Maternal E. coli strains are transmitted to the newborn causing invasive neonatal disease. However, there is a lack of data regarding the phenotypic and genotypic characterization of E. coli strains colonizing pregnant women during labor.MethodsThis prospective study performed at the University of Oklahoma Medical Center (OUHSC) from March 2014 to December 2015, aimed to investigate the colonization rate, and the phylogeny, antibiotic resistance traits, and invasive properties of E. coli strains colonizing the cervix of fifty pregnant women diagnosed with preterm labor (PTL). Molecular analyses including bacterial whole-genome sequencing (WGS), were performed to examine phylogenetic relationships among the colonizing strains and compare them with WGS data of representative invasive neonatal E. coli isolates. Phenotypic and genotypic antibiotic resistance traits were investigated. The bacteria’s ability to invade epithelial cells in vitro was determined.ResultsWe recruited fifty women in PTL. Cervical samples yielded E. coli in 12 % (n=6). The mean gestational age was 32.5 (SD±3.19) weeks. None delivered an infant with E. coli disease. Phenotypic and genotypic antibiotic resistance testing did not overall demonstrate extensive drug resistance traits among the cervical E. coli isolates, however, one isolate was multi-drug resistant. The isolates belonged to five different phylogroups, and WGS analyses assigned each to individual multi-locus sequence types. Single nucleotide polymorphism-based comparisons of cervical E. coli strains with six representative neonatal E. coli bacteremia isolates demonstrated that only half of the cervical E. coli isolates were phylogenetically related to these neonatal invasive strains. Moreover, WGS comparisons showed that each cervical E. coli isolate had distinct genomic regions that were not shared with neonatal E. coli isolates. Cervical and neonatal E. coli isolates that were most closely related at the phylogenetic level had similar invasion capacity into intestinal epithelial cells. In contrast, phylogenetically dissimilar cervical E. coli strains were the least invasive among all isolates.Conclusions This pilot study showed that a minority of women in PTL were colonized in the cervix with E. coli, and colonizing strains were not phylogenetically uniformly representative of E. coli strains that commonly cause invasive disease in newborns. Larger studies are needed to determine the molecular characteristics of E. coli strains colonizing pregnant women associated with an increased risk of neonatal septicemia.

Clustered Regularly Interspaced Short Palindromic Repeat Analysis of Clonal Complex 17 Serotype III Group B Streptococcus Strains Causing Neonatal Invasive Diseases.

Group B Streptococcus (GBS) is an important pathogen of neonatal infections, and the clonal complex (CC)-17/serotype III GBS strain has emerged as the dominant strain. The clinical manifestations of CC17/III GBS sepsis may vary greatly but have not been well-investigated. A total of 103 CC17/III GBS isolates that caused neonatal invasive diseases were studied using a new approach based on clustered regularly interspaced short palindromic repeats (CRISPR) loci and restriction fragment length polymorphism (RFLP) analyses. All spacers of CRISPR loci were sequenced and analyzed with the clinical presentations. After CRISPR-RFLP analyses, a total of 11 different patterns were observed among the 103 CRISPR-positive GBS isolates. GBS isolates with the same RFLP patterns were found to have highly comparable spacer contents. Comparative sequence analysis of the CRISPR1 spacer content revealed that it is highly diverse and consistent with the dynamics of this system. A total of 29 of 43 (67.4%) spacers displayed homology to reported phage and plasmid DNA sequences. In addition, all CC17/III GBS isolates could be categorized into three subgroups based on the CRISPR-RFLP patterns and eBURST analysis. The CC17/III GBS isolates with a specific CRISPR-RFLP pattern were more significantly associated with occurrences of severe sepsis (57.1% vs. 29.3%, p = 0.012) and meningitis (50.0% vs. 20.8%, p = 0.009) than GBS isolates with RFLP lengths between 1000 and 1300 bp. Whole-genome sequencing was also performed to verify the differences between CC17/III GBS isolates with different CRISPR-RFLP patterns. We concluded that the CRISPR-RFLP analysis is potentially applicable to categorizing CC17/III GBS isolates, and a specific CRISPR-RFLP pattern could be used as a new biomarker to predict meningitis and illness severity after further verification.

Genomic Characterization of Serotype III/ST-17 Group B Streptococcus Strains with Antimicrobial Resistance Using Whole Genome Sequencing.

Background: Antibiotic-resistant type III/ST-17 Streptococcus agalactiae (group B Streptococcus, GBS) strain is predominant in neonatal invasive GBS diseases. We aimed to investigate the antibiotic resistance profiles and genetic characteristics of type III/ST-17 GBS strains. Methods: A total of 681 non-duplicate GBS isolates were typed (MLST, capsular types) and their antibiotic resistances were performed. Several molecular methods (WGS, PCR, sequencing and sequence analysis) were used to determine the genetic context of antibiotic resistant genes and pili genes. Results: The antibiotic resistant rates were significantly higher in type Ib (90.1%) and type III (71.1%) GBS isolates. WGS revealed that the loss of PI-1 genes and absence of ISSag5 was found in antibiotic-resistant III/ST-17 GBS isolates, which is replaced by a ~75-kb integrative and conjugative element, ICESag37, comprising multiple antibiotic resistance and virulence genes. Among 190 serotype III GBS isolates, the most common pilus island was PI-2b (58.4%) alone, which was found in 81.3% of the III/ST-17 GBS isolates. Loss of PI-1 and ISSag5 was significantly associated with antibiotic resistance (95.5% vs. 27.8%, p < 0.001). The presence of ICESag37 was found in 83.6% of all III/ST-17 GBS isolates and 99.1% (105/106) of the antibiotic-resistant III/ST-17 GBS isolates. Conclusions: Loss of PI-1 and ISSag5, which is replaced by ICESag37 carrying multiple antibiotic resistance genes, accounts for the high antibiotic resistance rate in III/ST-17 GBS isolates. The emerging clonal expansion of this hypervirulent strain with antibiotic resistance after acquisition of ICESag37 highlights the urgent need for continuous surveillance of GBS infections.

Population Genomics Reveals Distinct Temporal Association with the Emergence of ST1 Serotype V Group B Streptococcus and Macrolide Resistance in North America.

Identified in the 1970s as the leading cause of invasive bacterial disease in neonates and young infants, group B Streptococcus (GBS) is now also recognized as a significant cause of morbidity and mortality among adults with underlying medical conditions and the elderly. Concomitant with the increasing incidence of GBS invasive disease in adults is the rise of resistance among GBS isolates to second line antibiotics. Previous research shows that among serotype V GBS, one of the most common capsular types causing adult invasive disease, sequence type 1 (ST1), accounts for an overwhelming majority of adult invasive disease isolates and frequently harbors macrolide resistance. In this study, using whole-genome sequencing data from strains isolated in the United States and Canada over a 45-year period, we examined the association of antimicrobial resistance with the emergence of invasive serotype V ST1 GBS. Our findings show a strong temporal association between increased macrolide resistance and the emergence of serotype V ST1 GBS subpopulations that currently co-circulate to cause invasive disease in adults and young infants. ST1 GBS subpopulations are defined, in part, by the presence of macrolide resistance genes in mobile genetic elements. Increased frequency of macrolide resistance-encoding mobile genetic elements among invasive GBS ST1 strains suggests the presence of such elements contributes to GBS virulence. Our work provides a foundation for the investigation of genetic features contributing to the increasing prevalence and pathogenesis of serotype V GBS in adult invasive disease.

Development and Immunogenicity of a Prototype Multivalent Group B Streptococcus Bioconjugate Vaccine.

Group B Streptococcus (GBS) is a leading cause of neonatal infections and invasive diseases in nonpregnant adults worldwide. Developing a protective conjugate vaccine targeting the capsule of GBS has been pursued for more than 30 years; however, it has yet to yield a licensed product. In this study, we present a novel bioconjugation platform for producing a prototype multivalent GBS conjugate vaccine and its subsequent analytical and immunological characterizations. Using a glycoengineering strategy, we generated strains of Escherichia coli that recombinantly express the type Ia, type Ib, and type III GBS capsular polysaccharides. We then combined the type Ia-, Ib-, and III-capsule-expressing E. coli strains with an engineered Pseudomonas aeruginosa exotoxin A (EPA) carrier protein and the PglS oligosaccharyltransferase. Coexpression of a GBS capsule, the engineered EPA protein, and PglS enabled the covalent attachment of the target GBS capsule to an engineered serine residue on EPA, all within the periplasm of E. coli. GBS bioconjugates were purified, analytically characterized, and evaluated for immunogenicity and functional antibody responses. This proof-of-concept study signifies the first step in the development of a next-generation multivalent GBS bioconjugate vaccine, which was validated by the production of conjugates that are able to elicit functional antibodies directed against the GBS capsule.

Complicated Streptococcus agalactiae Sepsis with/without Meningitis in Young Infants and Newborns: The Clinical and Molecular Characteristics and Outcomes.

Background: Streptococcus agalactiae (also known as group B streptococcus, GBS) is associated with high mortality and morbidity rates in infants, especially those with complicated GBS sepsis, defined as those with meningitis, severe sepsis and/or septic shock. We aimed to characterize the clinical and molecular characteristics and risk factors for adverse outcomes of neonates with invasive GBS diseases. Methods: From 2003 to 2020, all neonates with invasive GBS diseases who were hospitalized in a tertiary-level neonatal intensive care unit (NICU) were enrolled. The GBS isolates underwent serotyping, multilocus sequence typing (MLST) and antibiotic susceptibility testing. We compared cases of complicated GBS sepsis with uncomplicated GBS bacteremia. Results: During the study period, a total of 188 neonates (aged less than 6 months old) with invasive GBS diseases were identified and enrolled. Among them, 119 (63.3%) had uncomplicated GBS bacteremia and 69 (36.7%) neonates had complicated GBS sepsis, including meningitis (25.5%, n = 48) and severe sepsis or septic shock. Among neonates with complicated GBS sepsis, 45 (65.2%) had neurological complications, and 21 (42.0%) of 50 survivors had neurological sequelae at discharge. The overall final mortality rate was 10.1% (19 neonates died). Type III/ST-17 GBS isolates accounted for 56.5% of all complicated GBS sepsis and 68.8% of all GBS meningitis, but this strain was not significantly associated with worse outcomes. The antimicrobial resistance rate among the invasive GBS isolates was obviously increasing in the past two decades. After multivariate logistic regression analysis, neonates with thrombocytopenia and respiratory failure were independently associated with final adverse outcomes. Conclusions: a total of 36.7% of all neonatal invasive GBS diseases were associated with complicated sepsis with/without meningitis. Given the high mortality and morbidity rates in neonates with complicated GBS sepsis, further studies for early identification of specific strains, risk factors or genetic mechanisms that will cause complicated GBS sepsis are urgently needed in the future.

Estimation of country-level incidence of early-onset invasive Group B Streptococcus disease in infants using Bayesian methods.

Neonatal invasive disease caused by Group B Streptococcus (GBS) is responsible for much acute mortality and long-term morbidity. To guide development of better prevention strategies, including maternal vaccines that protect neonates against GBS, it is necessary to estimate the burden of this condition globally and in different regions. Here, we present a Bayesian model that estimates country-specific invasive GBS (iGBS) disease incidence in children aged 0 to 6 days. The model combines different types of epidemiological data, each of which has its own limitations: GBS colonization prevalence in pregnant women, risk of iGBS disease in children born to GBS-colonized mothers and direct estimates of iGBS disease incidence where available. In our analysis, we present country-specific maternal GBS colonization prevalence after adjustment for GBS detection assay used in epidemiological studies. We then integrate these results with other epidemiological data and estimate country-level incidence of iGBS disease including in countries with no studies that directly estimate incidence. We are able to simultaneously estimate two key epidemiological quantities: the country-specific incidence of early-onset iGBS disease, and the risk of iGBS disease in babies born to GBS-colonized women. Overall, we believe our method will contribute to a more comprehensive quantification of the global burden of this disease, inform cost-effectiveness assessments of potential maternal GBS vaccines and identify key areas where data are necessary.

Phenotypic changes in group B streptococci grown in the presence of the polyols, erythritol, sorbitol and mannitol

BackgroundGroup B streptococci (GBS) are important neonatal bacterial pathogens that can cause severe invasive disease in the newborn. It is thought that in many cases of invasive neonatal GBS disease, the bacteria ascend the vagina into the uterus and infect the amniotic fluid surrounding the fetus. Important constituents of this environment include the polyols or sugar alcohols of which erythritol, sorbitol and mannitol are examples. The aim of our study was to investigate the effect of polyols on GBS grown in media containing these sugar alcohols.ResultsGBS incubated in varying concentrations of polyols (erythritol, sorbitol or mannitol) did not display any significant enhancement or inhibition of bacterial growth. However, growth of GBS in the presence of erythritol significantly increased the surface expression of GBS-PGK (a plasminogen binding protein) 1.25 to 1.5-fold depending on the erythritol concentration and significantly enhanced the survival in human blood 3X to 18X depending on the concentration of polyol used. Interestingly, GBS grown in 1% erythritol significantly increased invasion by the bacteria of HeLa cells (epithelial cell line) (150% vs 100%) however, at higher concentrations (2% or 4% of polyol) the number of CFUs was significantly reduced (55-75% vs 100%) suggesting higher concentrations of polyols may inhibit invasion. Erythritol also increased GBS hemolytic activity as well as enhancing biofilm formation 1.4X to 3.3X depending on the concentration of polyol used.ConclusionsGBS grown in the presence of polyols alters the bacteria’s phenotype resulting in changes associated with GBS virulence. This effect was greatest for the polyol erythritol.

Trends in molecular characteristics and antimicrobial resistance of group B streptococci: a multicenter study in Serbia, 2015\u20132020

Group B Streptococcus (GBS) is a major cause of neonatal morbidity and mortality. Serbia has not fully implemented preventive measures against GBS neonatal diseases. Therefore, we aimed to assess the maternal GBS colonisation and invasive neonatal disease rate, to reveal the trends of antimicrobial resistance and serotype distribution of GBS from various patient groups. Randomly selected non-invasive (n = 991) and all invasive GBS (n = 80) collected throughout Serbia from 2015 to 2020 were tested for antimicrobial susceptibility, capsular typing, and hvgA detection. Overall, 877/5621 (15.6%) pregnant women were colonised with GBS. Invasive GBS infections incidence in infants (0.18/1000 live births) showed a decreasing trend (0.3 to 0.1/1000 live births). Type III was overrepresented in infants with invasive infections (n = 35, 58.3%), whereas type V predominated among colonised adults (n = 224, 25.5%) and those with noninvasive (n = 37, 32.5%) and invasive infections (n = 8, 40%). The hypervirulent clone III/ST17 was highly associated with invasive infections (n = 28, 35%), particularly late-onset disease (n = 9, 47.4%), showing an increase from 12.3 to 14.8%. The GBS resistance to erythromycin and clindamycin was 26.7% and 22.1%, respectively, with an upward trend. The emergence of the hypervirulent clone III/ST17 and the escalation in GBS resistance highlight an urgent need for continuous monitoring of GBS infections.

Genomic and phenotypic characterisation of invasive neonatal and colonising group B Streptococcus isolates from Slovenia, 2001\u20132018

BackgroundGroup B Streptococcus (GBS) is the leading cause of invasive neonatal disease in the industrialized world. We aimed to genomically and phenotypically characterise invasive GBS isolates in Slovenia from 2001 to 2018 and contemporary colonising GBS isolates from screening cultures in 2018.MethodsGBS isolates from 101 patients (invasive isolates) and 70 pregnant women (colonising isolates) were analysed. Basic clinical characteristics of the patients were collected from medical records. Antimicrobial susceptibility and phenotypic capsular serotype were determined. Whole-genome sequencing was performed to assign multilocus sequence types (STs), clonal complexes (CCs), pathogenicity/virulence factors, including capsular genotypes, and genome-based phylogeny.ResultsAmong invasive neonatal disease patients, 42.6% (n = 43) were females, 41.5% (n = 39/94) were from preterm deliveries (< 37 weeks gestation), and 41.6% (n = 42) had early-onset disease (EOD). All isolates were susceptible to benzylpenicillin with low minimum inhibitory concentrations (MICs; ≤0.125 mg/L). Overall, 7 serotypes were identified (Ia, Ib, II-V and VIII); serotype III being the most prevalent (59.6%). Twenty-eight MLST STs were detected that clustered into 6 CCs. CC-17 was the most common CC overall (53.2%), as well as among invasive (67.3%) and non-invasive (32.9%) isolates (p < 0.001). CC-17 was more common among patients with late-onset disease (LOD) (81.4%) compared to EOD (47.6%) (p < 0.001). The prevalence of other CCs was 12.9% (CC-23), 11.1% (CC-12), 10.5% (CC-1), 8.2% (CC-19), and 1.8% (CC-498). Of all isolates, 2.3% were singletons.ConclusionsA high prevalence of hypervirulent CC-17 isolates, with low genomic diversity and characteristic profile of pathogenicity/virulence factors, was detected among invasive neonatal and colonising GBS isolates from pregnant women in Slovenia. This is the first genomic characterisation of GBS isolates in Slovenia and provides valuable microbiological and genomic baseline data regarding the invasive and colonising GBS population nationally. Continuous genomic surveillance of GBS infections is crucial to analyse the impact of IND prevention strategies on the population structure of GBS locally, nationally, and internationally.

Molecular characteristics of the new emerging global clone ST1193 among clinical isolates of Escherichia coli from neonatal invasive infections in China.

Sequence type 1193 (ST1193) constitutes an emerging fluoroquinolone-resistant Escherichia coli clone in several countries. However, reports of such isolates in neonatal invasive diseases are limited. Here, we assessed the antimicrobial resistance and molecular characteristics of E. coli ST1193 isolates causing neonatal bloodstream infections and meningitis in China. A total of 56 E. coli isolates were collected from neonatal blood and cerebrospinal fluid between September 2009 and June 2015. Antimicrobial susceptibility was evaluated using E-test methods. Polymerase chain reaction amplification was used to detect antibiotic resistance genes including blaTEM, blaSHV, and blaCTX-M groups. Molecular typing was performed via multi-locus sequence typing. Among 56 E. coli isolates, 17 (17/56, 30.4%) were extended-spectrum β-lactamase (ESBL) producers, and 37(37/56, 66.1%) were multidrug-resistant. The most frequent sequence types were ST1193 (12/56), followed by ST95 and ST62. ST1193 isolates exhibited a 91.7% resistance rate to ciprofloxacin, amoxicillin, and sulfonamides, and 83.3% resistance rate to tetracycline. A total of 4 (33.3%) among the 12 ST1193 isolates were ESBL producers, of which three carried both blaCTX-M-15 and blaTEM genes with the remaining isolate harboring blaCTX-M-27 and blaTEM genes. Additionally, 1 of the 3 ST1193 isolates obtained from cerebrospinal fluid was an ESBL producer that carried both blaCTX-M-15 and blaTEM genes. This study revealed for the first time the molecular characteristics of E. coli ST1193 causing neonatal invasive diseases in China. Notably, we found that ST1193 isolates were multidrug-resistant. Further multicenter studies are needed to assess the molecular epidemiology of ST1193 in China to control its spread.

Distribution of Pilus island and antibiotic resistance genes in Streptococcus agalactiae obtained from vagina of pregnant women in Yazd, Iran.

Background and Objectives:Due to the important role of Streptococcus agalactiae, Group B streptococci (GBS), in production of invasive disease in neonates, investigation regarding the pathogenicity and antibiotic resistance factors is necessary in selecting the appropriate therapeutic agents. Beside capsule, the pilus has been currently recognized as an important factor in enhancing the pathogenicity of GBS. Resistance of GBS to selected antibiotics is noticeably increasing which is mainly due to the anomalous use of these drugs for treatment. The aim of this study was to determine the prevalence of pili genes followed by antibiotic susceptibility of GBS, previously serotyped, isolated from pregnant women in the city of Yazd, Iran.Materials and Methods:Fifty seven GBS from pregnant women were subjected to multiplex PCR for determination of PI-1, PI-2a and PI-2b pilus-islands and simultaneously, the phenotype of antibiotic resistance to penicillin, tetracycline, erythromycin, clindamycin, gentamycin and levofloxacin was determined. Antibiotic resistance genes (ermA, ermB, mefA, tetM, int-Tn) were further diagnosed using PCR and multiplex PCR.Results:PI-1+PI-2a with 71.9%; followed by PI-2a (21.1%) and PI-2b (7%) were observed. PI-1+PI-2a in serotype III was (73.2%), serotype II, Ia, Ib and V were 12.2%, 9.8%, 2.4% and 2.4% respectively. GBS penicillin sensitive was 89.5% and 96.5% resistance to tetracycline. The frequency of resistance genes were as follows: tetM (93%), ermA (33.3%), ermB (8.8%), int-Tn (80.7%) and mefA (0).Conclusion:Majority of GBS contained PI-1+PI-2a. Hence presence of this pilus stabilizes the colonization, therefore designing a program for diagnosing and treatment of infected pregnant women seems to be necessary.

Bacterial invasive infections in a neonatal intensive care unit: a 13 years microbiological report from an Italian tertiary care centre.

SummaryIntroductionTo evaluate the aetiology of neonatal invasive diseases (positive cultures from blood or cerebrospinal fluid, CSF) due to bacteria other than coagulase-negative staphylococci in a large tertiary care centre and compare with results of surveillance cultures.MethodsRetrospective analysis of microbiological data of children admitted in neonatal intensive care unit (NICU) of a large tertiary care centre from 2005 to 2018.Results230 bacterial strains, 223 from blood and 7 from CSF, respectively, were detected as cause of invasive infections, while 152 were detected in surveillance cultures. Methicillin-susceptible Staphylococcus aureus (MSSA) was the most frequently isolated pathogen both in invasive infections (18%) and colonizations (23%) followed by Escherichia coli (16% on invasive disease and 20% of colonizations). Other common bacteria include Enterococcus faecalis and Streptococcus agalactiae for invasive disease and methicillin-resistant Staphylococcus aureus in colonizations. Invasive infection was due to a pathogen detected in surveillance cultures in 33% of cases. In more than 50% of invasive diseases the identified pathogen was not present in surveillance cultures.ConclusionsThe high percentage of invasive infections due to bacteria not previously identified in surveillance cultures raises doubts about the efficiency of this procedure and highlights the need to search for alternative infection sources. This finding and the high prevalence of invasive infections due to nosocomial pathogens such as Staphylococcus aureus could be the result of horizontal transmission between patients through the hands of health care professionals, emphasizing once again the importance of applying stringent hand hygiene procedures and isolation standards.

Increasing incidence of group B streptococcus neonatal infections in the Netherlands is associated with clonal expansion of CC17 and CC23

Group B streptococcus (GBS) is the leading cause of neonatal invasive disease worldwide. In the Netherlands incidence of the disease increased despite implementation of preventive guidelines. We describe a genomic analysis of 1345 GBS isolates from neonatal (age 0–89 days) invasive infections in the Netherlands reported between 1987 and 2016. Most isolates clustered into one of five major lineages: CC17 (39%), CC19 (25%), CC23 (18%), CC10 (9%) and CC1 (7%). There was a significant rise in the number of infections due to isolates from CC17 and CC23. Phylogenetic clustering analysis revealed that this was caused by expansion of specific sub-lineages, designated CC17-A1, CC17-A2 and CC23-A1. Dating of phylogenetic trees estimated that these clones diverged in the 1960s/1970s, representing historical rather than recently emerged clones. For CC17-A1 the expansion correlated with acquisition of a new phage, carrying gene encoding a putative cell-surface protein. Representatives of CC17-A1, CC17-A2 and CC23-A1 clones were identified in datasets from other countries demonstrating their global distribution.

T cell response during Group B Streptococcus vaginal colonization and ascending infection

Abstract Pre-term birth, miscarriage, and other adverse pregnancy outcomes remain the primary cause of neonatal death and are associated with bacterial ascending infections within the female reproductive tract. Group B Streptococcus (GBS), a vaginal tract colonizer, is a leading contributor to adverse pregnancy outcomes and neonatal invasive disease. We have developed a mouse model of GBS vaginal colonization and ascending infection and have observed increased IL-17 production in mice that cleared GBS colonization compared to those still colonized. Thus, we hypothesize that IL-17 and IL-17-producing cells may be important for host defense; yet, the immune dynamics during GBS vaginal persistence and ascending infection/adverse pregnancy outcomes remain unknown. T cells are a major source of IL-17 in the mucosa. To assess the role of adaptive immunity during GBS colonization, we colonized RAG1+/+ and RAG1−/− mice with GBS and observed increased persistence of GBS in the vaginal tract of the RAG1−/− mice. To determine the cellular source of IL-17 within the reproductive tract of GBS-colonized mice, we isolated immune cells from vaginal, cervical, and uterine tissues at the time of GBS clearance and performed flow cytometry. TCRɣδ+ cells comprised the highest percentage of RORɣT+ immune cells in the vagina, cervix, and uterus. We further observed an increased percentage of TCRɣδ+ cells in the uterus of GBS-colonized mice compared to naïve mice at day 9 post-inoculation, at which point half the mice had cleared. We hypothesize that IL-17-producing TCRɣδ+ cells contribute to GBS clearance in the murine reproductive tract. Future studies will assess GBS vaginal persistence and ascending infection in IL-17- and TCRɣδ-deficient mouse lines.

Prevalence and Serotype Determination of Streptococcus agalactiae Isolated From Non-Pregnant Women in Tehran, Iran

Consequence of Streptococcus agalactiae, Group B Streptococcus (GBS) relating infant’s diseases are well documented. Although many women carry this bacterium in their vagina, they may transfer to their infant during delivery and may result in different neonatal invasive diseases. The aim of this study was to determine the prevalence of GBS and serotyping the isolated species among un-selective non-pregnant women who attended two gynecology clinics in Tehran. In this cross-sectional study, a total of 560 vaginal samples collected from non-pregnant women. Following inoculation of the specimen on Blood Agar, the standard technology was applied for the final identification of GBS. Detected GBS species were further confirmed using specific PCR directed on dlts gene. Capsular serotyping was done by using the multiplex PCR method. The chi-square method was used for statistical analysis. Fifty (8.9%) out of 560 non-pregnant women were carriers of GBS. The most common types were III (36%), followed by type II (32%), Ia (26%), and Ib (6%), respectively. Results represent that the prevalence rate of GBS in non-pregnant women was reliable and similar to what obtained from pregnant women. In addition, the serotype III was found the most dominant types, as well as other investigations in the Tehran area. Therefore, vaccine designation based on type III is recommended.

Bacterial Invasive infections in a neonatal intensive care unit: a 13 years microbiological report from a tertiary referral centre

Introduction: To evaluate the aetiology of neonatal invasive diseases (positive cultures from blood or cerebrospinal fluid) due to bacteria other than coagulase-negative staphylococci in a large third-level centre and compare with results of surveillance cultures. Methods: Retrospective analysis of microbiological data of children admitted in neonatal intensive care unit (NICU) of a large third-level centre from 2005 to 2018. Results: 230 bacterial strains, 223 from blood and 7 from CSF, were detected as cause of invasive infections, while 152 were detected in surveillance cultures. Methicillin-susceptible Staphylococcus aureus (MSSA) was the most frequently isolated pathogen both in invasive infections (18%) and colonizations (23%) followed by Escherichia coli (16% on invasive disease and 20% of colonizations). Other common bacteria include Enterococcus faecalis and Streptococcus agalactiae for invasive disease and Meticillin-resistant Stapylococcus aureus (MRSA) with regard to colonization. Disease was due to a pathogen detected in surveillance cultures flora in 33%. In more than 50% of invasive diseases the identified pathogen was not present in surveillance cultures. Conclusion: The high percentage of invasive infections due to bacteria not previously identified in surveillance cultures raises doubts about the efficiency of this procedure and highlights the need to search for alternative infection sources. This finding and the high prevalence of invasive infections due to nosocomial pathogens such as Staphylococcus aureus could be the result of horizontal transmission between patients through the hands of health care professionals, emphasizing once again the importance of applying stringent hand hygiene procedures and isolation standards.