Invasive Neonatal Disease Research Articles

Development of bioluminescent Group B streptococcal strains for longitudinal infection studies.

Group B Streptococcus (GBS) remains the leading bacterial cause of invasive neonatal disease, resulting in substantial morbidity and mortality. New therapeutic approaches beyond antibacterial treatment to prevent neonatal disease outcomes are urgent. One significant limitation in studying GBS disease and progression is the lack of non-invasive technologies for longitudinal studies. Here, we develop and compare three bioluminescent GBS strains for in vivo pathogenic analysis. Bioluminescence is based on the luxABCDE operon on a replicative vector (luxGBS-CC17), and the red-shifted firefly luciferase on a replicative vector (fflucGBS-CC17) or integrated in the genome (glucGBS-CC17). We show that luxGBS-CC17 is suitable for in vitro analysis but does not produce a significant bioluminescent signal in infected pups. In contrast, the fflucGBS-CC17 results in a strong bioluminescent signal proportional to the organ colonisation level. However, the stability of the replicative vector depends on the route of infection, especially when pups acquire the bacteria from infected vaginal mucosa. Stable chromosomal integration of luciferase in glucGBS-CC17 leads to significant bioluminescence in both haematological and vertical infection models associated with high systemic colonisation. These strains will allow the preclinical evaluation of treatment efficacy against GBS invasive disease using whole-mouse bioluminescence imaging.

Group B Streptococcus and Intraamniotic Inflammation and Infection.

Intraamniotic inflammation and infection complicate 2% to 5% of term deliveries. Group B Streptococcus (GBS) is a common cause of intraamniotic infection associated with invasive neonatal disease and maternal morbidity. Universal vaginal-rectal screening for GBS colonization is recommended between 36 and 37 weeks. Intrapartum antibiotic prophylaxis is recommended for individuals with positive GBS screens and other risk factors. Intravenous penicillin is the preferred antimicrobial agent. Individuals with penicillin allergies may receive cefazolin for low-risk allergies and either clindamycin or vancomycin for high-risk allergies, depending on their antimicrobial susceptibilities. Clinical trials are underway to evaluate the safety and immunogenicity of maternal anti-GBS vaccine candidates.

Genetic markers associated with host status and clonal expansion of Group B Streptococcus in the Netherlands.

Certain Group B Streptococcus (GBS) genotypes are associated with invasive disease in neonates. We conducted a comparative genomic analysis of GBS isolates from neonatal disease and maternal carriage in the Netherlands to determine distribution of genetic markers between the two host groups. Whole genome sequencing was used to characterise 685 neonatal invasive isolates (2006-2021) and 733 maternal carriage isolates (2017-2021) collected in the Netherlands. Clonal complex (CC) 17 and serotype III were significantly more common in disease while carriage isolates were associated with serotypes II, IV, V as well as CC1. Previously reported CC17-A1 sub-lineage was dominant among disease isolates and significantly less common in carriage. The phiStag1 phage, previously associated with expansion of invasive CC17 isolates in the Netherlands, was more common among disease isolates compared to carriage isolates overall, however it was equally distributed between CC17 isolates from carriage and disease. Prevalence of antimicrobial resistance genes was overall lower in disease compared to carriage isolates, but increased significantly over time, mediated by rise in prevalence of a multidrug resistance element ICESag37 among disease isolates. There is a stable association between certain GBS genotypes and invasive disease, which suggests opportunities for developing more precise disease prevention strategies based on GBS targeted screening. In contrast, GBS mobile genetic elements appear less likely to be correlated with carriage or disease, and instead are associated with clonal expansion events across the GBS population.

Prevalence of Group B Streptococcus Colonization in Pregnant Women in Iran: A Systematic Review and Meta-Analysis

Introduction: Group B Streptococcus (GBS) or Streptococcus agalactiae is one of the main causes of invasive infections such as meningitis and septicemia in infants. Genital colonization with group B streptococci has been related to increased risk of premature delivery, and premature infants are at greater risk of disease. There is limited information about the prevalence of rectovaginal GBS colonization in pregnant women in Iran. The aim of the present study was investigating the prevalence of group B streptococcus colonization in pregnant women in Iran. Methods: Information of this study was attained by searching on databases including PubMed, Google Scholar, Scopus, Web of Science and SID using relevant keywords and without time limit. Then, the studies containing the inclusion criteria were reviewed. The data were analyzed using Comprehensive MetaAnalysis software (Biostat V3). Heterogeneity between studies was investigated with the I2 index and based on the results of heterogeneity, the random effect model was implemented in order to determine the prevalence of GBS in pregnant women. Results: Out of 231 articles, 15 articles were included in the study. The analysis of 15 studies showed that the prevalence of GBS in Iranian pregnant women was 12.2% (95% CI: 9.9-15.1). Conclusion: In order to prevent the invasive neonatal disease, screening for GBS colonization is recommended for pregnant women in 35–37 weeks of gestation. Regarding the lack of preventive strategies for GBS infections in Iran, national guidelines should be established to guide the obstetricians, midwives, and nurses on the prevention of GBS infections.

Emergence of High-Level Gentamicin Resistance in Streptococcus agalactiae Hypervirulent Serotype IV ST1010 (CC452) Strains by Acquisition of a Novel Integrative and Conjugative Element.

Streptococcus agalactiae (group B streptococci, GBS) is responsible for severe infections in both neonates and adults. Currently, empiric antimicrobial therapy for sepsis and meningitis is the combined use of penicillin and gentamicin due to the enhanced bactericidal activity. However, high-level gentamicin resistance (HLGR) abrogates the synergism. The rate of HLGR was investigated within a dataset of 433 GBS strains collected from cases of invasive disease in both adults and neonates as well as from pregnant carriers. GBS isolates (n = 20, 4.6%) presented with HLGR (gentamicin MIC breakpoint >1024 mg/L) that was differently diffused between strains from adults or neonates (5.2% vs. 2.8%). Notably, 70% of HLGR GBS strains (14 isolates) were serotype IV. Serotype IV HLGR-GBS isolates were susceptible to all antibiotics tested, exhibited the alpha-C/HvgA/PI-2b virulence string, and belonged to sequence type 1010 (clonal complex (CC) 452). The mobile element that harbored the HLGR aac(6')-aph(2)″ gene is a novel integrative and conjugative element (ICE) about 45 kb long, derived from GBS 515 ICE tRNALys. The clonal expansion of this HLGR hypervirulent serotype IV GBS CC452 sublineage may pose a threat to the management of infections caused by this strain type.

Development and performance evaluation of a qPCR-based assay for the fully automated detection of group B Streptococcus (GBS) on the Panther Fusion Open Access system.

Streptococcus agalactiae [group B Streptococcus (GBS)] poses a major threat as the primary cause of early-onset neonatal invasive disease, particularly when mothers are colonized rectovaginally. Although culture remains the gold standard for antepartum GBS screening, quantitative polymerase chain reaction (qPCR) offers advantages in terms of sensitivity and turnaround time. The aim of this study was to validate the clinical utility of an automated qPCR laboratory-developed test (LDT) for antepartum GBS screening using the Panther Fusion Open Access system (Hologic, California, USA). The LDT targeted a conserved region of the GBS surface immunogenic protein gene, demonstrating no cross-reactivity and high coverage (99.82%-99.99%). The limit of detection (LoD) was 118 CFU/mL. Comparison with commercial qPCR assays (Panther Fusion GBS and VIASURE Streptococcus B Real-Time) revealed an overall agreement of 99.7%, with a robust Cohen's kappa coefficient of 0.992. Testing of 285 rectovaginal swabs from pregnant women and 15 external quality assessment samples demonstrated exceptional diagnostic performance of the LDT, achieving a diagnostic sensitivity and specificity of 100%, underscoring its accuracy. Prevalence and predictive values were also determined to reinforce test reliability. Our research highlights the limitations of culture-based screening and supports the suitability of our qPCR-based LDT for GBS detection in a clinical setting.IMPORTANCERectovaginal colonization by GBS is a major risk factor for early-onset invasive neonatal disease. The most effective approach to reducing the incidence of early-onset disease (EOD) has been described as universal screening, involving assessment of GBS colonization status in late pregnancy and intrapartum antibiotic prophylaxis. Despite its turnaround time and sensitivity limitations, culture remains the gold standard method for GBS screening. However, nucleic acid amplification-based tests, such as qPCR, have been utilized due to their speed and high sensitivity and specificity. This study validated the clinical usefulness of an automated qPCR-LDT for antepartum GBS screening through the Panther Fusion Open Access system (Hologic). Our study addresses the critical need for more robust, sensitive, and rapid strategies for GBS screening in pregnant women that could favorably impact the incidence of EOD.

Antimicrobial Resistance Profile of Group B Streptococci Colonization in a Sample Population of Pregnant Women from Romania.

Group B Streptococcus (GBS) represents one of the leading causes of life-threatening invasive disease in pregnant women and neonates. Rates of GBS colonization vary by region, but studies on maternal GBS status are limited in Romania. This study aims to identify the prevalence of colonization with GBS and whether the obstetrical characteristics are statistically associated with the study group's antimicrobial susceptibility patterns of tested GBS strains. This observational study was conducted between 1 May and 31 December 2021 at The Department of Obstetrics and Gynecology at Elias University Emergency Hospital (EUEH) in Bucharest, Romania. A total of 152 samples were positive for GBS and included in the study according to the inclusion criteria. As a result, the prevalence of colonized patients with GBS was 17.3%. GBS isolated in this population had the highest resistance to erythromycin (n = 38; 25%), followed by clindamycin (n = 36; 23.7%). Regarding the susceptibility patterns of tested strains to penicillin, the 152 susceptible strains had MIC breakpoints less than 0.06 μg/μL. The susceptibility patterns of tested strains to linezolid indicated three resistant strains with low levels of resistance (MICs ranging between 2 and 3 μg/μL). Multidrug resistance (at least three antibiotic classes) was not observed. In conclusion, although GBS naturally displays sensitivity to penicillin, the exact bacterial susceptibility testing should be performed in all cases where second-line therapy is taken into consideration for treatment. We acknowledge the need for future actions to limit multidrug-resistant bacteria.

Obstetric and Neonatal Invasive Meningococcal Disease Caused by Neisseria meningitidis Serogroup W, Western Australia, Australia.

Three mother-baby pairs with invasive meningococcal disease occurred over 7 months in Western Australia, Australia, at a time when serogroup W sequence type 11 clonal complex was the predominant local strain. One mother and 2 neonates died, highlighting the role of this strain as a cause of obstetric and early neonatal death.

Anovaginal Colonization by Group B Streptococcus and Streptococcus anginosus among Pregnant Women in Brazil and Its Association with Clinical Features.

Streptococcus agalactiae (Group B Streptococcus; GBS) is a leading cause of neonatal invasive disease worldwide. GBS can colonize the human gastrointestinal and genitourinary tracts, and the anovaginal colonization of pregnant women is the main source for neonatal infection. Streptococcus anginosus, in turn, can colonize the human upper respiratory, gastrointestinal, and genitourinary tracts but has rarely been observed causing disease. However, in the last years, S. anginosus has been increasingly associated with human infections, mainly in the bloodstream and gastrointestinal and genitourinary tracts. Although anovaginal screening for GBS is common during pregnancy, data regarding the anovaginal colonization of pregnant women by S. anginosus are still scarce. Here, we show that during the assessment of anovaginal GBS colonization rates among pregnant women living in Rio de Janeiro, Brazil, S. anginosus was also commonly detected, and S. anginosus isolates presented a similar colony morphology and color pattern to GBS in chromogenic media. GBS was detected in 48 (12%) while S. anginosus was detected in 17 (4.3%) of the 399 anovaginal samples analyzed. The use of antibiotics during pregnancy and history of urinary tract infections and sexually transmitted infections were associated with the presence of S. anginosus. In turn, previous preterm birth was associated with the presence of GBS (p < 0.05). The correlation of GBS and S. anginosus with relevant clinical features of pregnant women in Rio de Janeiro, Brazil, highlights the need for the further investigation of these important bacteria in relation to this special population.

A Case of Extremely Premature Baby with Persistent Metabolic Acidosis, Hypoglycemia and Dyselectrolytemia Induced by Liposomal Amphotericin B

Amphotericin B is widely used in the treatment of neonatal invasive fungal disease. Liposomal amphotericin B (LAmB) is now preferred over conventional amphotericin B deoxycholate due to its lower kidney toxicity. However, it is essential to monitor the possible side effects of LAmB when treating extremely premature infants. Herein, we present a case of an extremely premature infant who exhibited persistent metabolic acidosis, hypoglycemia, and dyselectrolytemia after administration of LAmB for a suspected fungal infection.

Long-term surveillance of group B Streptococcus strains isolated from infection and colonization in pregnant women and newborns.

Introduction. Group B Streptococcus (GBS) remains the leading cause of bacterial neonatal infections worldwide, despite the spread of recommendations on vaginal screening and antibiotic prophylaxis.Hypothesis/Gap Statement. There is a need to evaluate the potential changes in GBS epidemiology over time following the introduction of such guidelines.Aim. Our aim was to perform a descriptive analysis of the epidemiological characteristics of GBS by conducting a long-term surveillance of strains isolated between 2000 and 2018, using molecular typing methods.Methodology. A total of 121 invasive strains, responsible for maternal infections (20 strains), fetal infections (8 strains) and neonatal infections (93 strains), were included in the study, representing all the invasive isolates during the period; in addition, 384 colonization strains isolated from vaginal or newborn samples were randomly selected. The 505 strains were characterized by capsular polysaccharide (CPS) type multiplex PCR assay and the clonal complex (CC) was assigned using a single nucleotide polymorphism PCR assay. Antibiotic susceptibility was also determined.Results. CPS types III (32.1 % of the strains), Ia (24.6 %) and V (19 %) were the most prevalent. The five main CCs observed were CC1 (26.3 % of the strains), CC17 (22.2 %), CC19 (16.2 %), CC23 (15.8 %) and CC10 (13.9 %). Neonatal invasive GBS diseases were predominantly due to CC17 isolates (46.3 % of the strains), which mainly express CPS type III (87.5 %), with a very high prevalence in late-onset diseases (76.2 %).Conclusion. Between 2000 and 2018, we observed a decrease in the proportion of CC1 strains, which mainly express CPS type V, and an increase in the proportion of CC23 strains, mainly expressing CPS type Ia. Conversely, there was no significant change in the proportion of strains resistant to macrolides, lincosamides or tetracyclines. The two molecular techniques used in our study provide almost as much information as classical serotyping and multilocus sequence typing, but are quicker, easy to perform, and avoid long sequencing and analysis steps.

Prophylaxis of Invasive Fungal Infection in Neonates: A Narrative Review for Practical Purposes

Candida albicans is the most frequent cause of invasive fungal disease in preterm and/or low birth weight neonates, followed by Candida parapsilosis, whilst infections from other species are rare. Considering the severity of the disease, associated with poor clinical signs and diagnostic difficulties, primary prophylaxis becomes relevant. This paper summarizes the pathogenesis and clinical presentation of invasive candidiasis in neonates, focusing on prophylaxis. For late onset invasive disease, e.g., those occurring after the 3rd (or 7th according to some definitions) day of life possible approaches are the use of fluconazole, recommended in case of weight <1000 g or <1500 g if the local incidence of invasive candidiasis is higher than 2%, or the use of nystatin (for patients < 1500 g). Micafungin must be used in case of colonization by Candida auris, or in centers with a high prevalence of this pathogen. Concurrently, correct management of the central venous catheter and isolation procedures, with special regard to patients colonized by resistant strains, are fundamental. Other approaches such as reduced use of H2 blockers and broad-spectrum antibiotics (e.g., 3rd generation cephalosporins or carbapenems) and promotion of breast feeding proved useful. Reduction of early-onset infections (those occurring in the first 3 days of life) can also be obtained by treating maternal vulvo-vaginal candidiasis, which can represent a fastidious problem during pregnancy. In this case, topic azoles (the only recommendable treatment) can represent a kind of "prophylaxis" of early neonatal candidiasis. However, it must always be remembered that prophylaxis reduces the risk of invasive candidiasis but can not completely eliminate its occurrence, with the parallel risk of selecting for antifungal-resistant strains. Clinicians must maintain a high level of suspicion to start an appropriate therapy and strict epidemiological surveillance to identify the occurrence of clusters and the appearance of strains resistant to prophylaxis.

Characteristics of Meningococcal Invasive Disease in Neonates and Virulence of the Corresponding Isolates

Background: The highest incidence of invasive meningococcal disease (IMD) is observed in infants. However, its prevalence in neonates (≤28 days of age) and the characteristics of the corresponding isolates are less described. This report aimed to analyze meningococcal isolates from neonates. Methods: We first screened the database of the national reference center for meningococci in France for confirmed neonatal IMD cases between 1999 and 2019. We then performed whole-genome sequencing on all cultured isolates, and we evaluated their virulence in a mouse model. Results: Fifty-three neonatal cases of IMD (mainly bacteremia) were identified (50 culture-confirmed cases and 3 PCR-confirmed cases) of a total of 10,149 cases (0.5%) but represented 11% of cases among infants of under 1 year of age. Nine cases (17%) occurred among neonates of 3 days of age and younger (early onset). The neonate isolates were often of serogroup B (73.6%) and belonged to the clonal complex CC41/44 (29.4%) with at least 68.5% of coverage by vaccines against serogroup B isolates. The neonatal isolates were able to infect mice although to variable levels. Conclusion: IMD in neonates is not rare and can be of early or late onsets suggesting that anti-meningococcal vaccination can target women planning to have a baby.

Neonatal invasive disease caused by Streptococcus agalactiae in Europe: the DEVANI multi-center study.

Group B streptococcus (GBS) remains a leading cause of invasive disease, mainly sepsis and meningitis, in infants < 3months of age and of mortality among neonates. This study, a major component of the European DEVANI project (Design of a Vaccine Against Neonatal Infections) describes clinical and important microbiological characteristics of neonatal GBS diseases. It quantifies the rate of antenatal screening and intrapartum antibiotic prophylaxis among cases and identifies risk factors associated with an adverse outcome. Clinical and microbiological data from 153 invasive neonatal cases (82 early-onset [EOD], 71 late-onset disease [LOD] cases) were collected in eight European countries from mid-2008 to end-2010. Respiratory distress was the most frequent clinical sign at onset of EOD, while meningitis is found in > 30% of LOD. The study revealed that 59% of mothers of EOD cases had not received antenatal screening, whilst GBS was detected in 48.5% of screened cases. Meningitis was associated with an adverse outcome in LOD cases, while prematurity and the presence of cardiocirculatory symptoms were associated with an adverse outcome in EOD cases. Capsular-polysaccharide type III was the most frequent in both EOD and LOD cases with regional differences in the clonal complex distribution. Standardizing recommendations related to neonatal GBS disease and increasing compliance might improve clinical care and the prevention of GBS EOD. But even full adherence to antenatal screening would miss a relevant number of EOD cases, thus, the most promising prophylactic approach against GBS EOD and LOD would be a vaccine for maternal immunization.

Clonal Complex 12 Serotype Ib Streptococcus agalactiae Strain Causing Complicated Sepsis in Neonates: Clinical Features and Genetic Characteristics.

Streptococcus agalactiae (group B Streptococcus [GBS]) is well known to cause serious diseases in infants. A serotype Ib GBS strain has recently emerged and become prevalent in Southeast Asia. We aimed to investigate the clinical and genetic characteristics of this strain. All neonates with invasive GBS diseases from a tertiary-level medical center in Taiwan between 2003 and 2020 were analyzed. The capsule serotyping, multilocus sequence typing, and antimicrobial resistance analyses were performed on all the invasive GBS isolates, and whole-genome sequencing (WGS) was performed specifically on the type Ib GBS strain. A total of 188 neonates with invasive GBS disease during the study period were identified. The type Ib GBS strain accounted for 7.4% (n = 14) of neonatal GBS invasive diseases. Almost all type Ib GBS isolates belonged to sequence type 12 (13/14, 92.9%) and clonal complex 12. Neonates with type Ib GBS disease had a significantly higher rate of complicated sepsis (10/14, 71.4%; P < 0.05) and sepsis-attributable mortality (6/14, 42.9%; P < 0.05). Additionally, type Ib GBS isolates had significantly higher rates of resistance to erythromycin and clindamycin (both 100%; P < 0.05) than other GBS serotypes. WGS revealed the presence of an ~75-kb integrative and conjugative element, ICESag37, comprising multiple antibiotic resistance and virulence genes, and PI-1 plus PI-2a were noted in all type Ib serotype 12 (ST12) GBS isolates; these isolates may be responsible for its high invasiveness and antimicrobial resistance rates. The genomic characteristics of the type Ib clonal complex 12 (CC12) GBS strain may account for the high illness severity associated with this strain and its antibiotic resistance. Continuous monitoring and advanced strategies to control the spread of type Ib CC12 GBS should be considered. IMPORTANCE A type Ib ST12 GBS strain is not a common isolate in neonatal invasive diseases and has been ignored for a long time. However, the recent literature and our data showed that such a GBS strain is associated with a significantly higher risk of severe sepsis, higher illness severity, and a significantly higher rate of sepsis-attributable mortality. This study found a novel gene cluster, including the presence of ICESag37 and specific pilus genes, carrying multiple antimicrobial resistance and virulence genes, which may be responsible for the clinical characteristics. Because of the higher mortality and severity of illness, we concluded that continuous monitoring of the type Ib ST12 GBS strain is warranted in the future.

Serum Beta-D-Glucan in the Diagnosis of Invasive Fungal Disease in Neonates, Children and Adolescents: A Critical Analysis of Current Data.

β-D-glucan (BDG) is a cell wall component of many pathogenic fungi. The detection of BDG as an assay is clinically broadly used as a diagnostic tool. However, the current data on BDG in paediatrics are limited, prompting specific considerations about when BDG can be used in neonates and children. We aimed to analyse the available data for the use of serum BDG in neonates and immunocompromised children and adolescents; as well as to understand the extent and characteristics of the use of BDG in children in Europe.

Virulence, phenotype and genotype characteristics of invasive group B Streptococcus isolates obtained from Swedish pregnant women and neonates

Group B streptococci (GBS) are bacteria that can cause preterm birth and invasive neonatal disease. Heterogeneous expression of virulence factors enables GBS to exist as both commensal bacteria and to become highly invasive. A molecular epidemiological study comparing GBS bacterial traits, genotype and host characteristics may indicate whether it is possible to predict the risk of perinatal invasive GBS disease and more accurately target intrapartum antibiotic prophylaxis. A total of 229 invasive GBS isolates from Swedish pregnant women or neonates were assessed for virulence and phenotypic traits: hemolysis zone, hemolytic pigment (Granada agar), Streptococcus B Carrot Broth (SBCB) assay, CAMP factor, and hyaluronidase activity. Genes regulating hemolytic pigment synthesis (covR/covS, abx1, stk1, stp1) were sequenced. Of the virulence factors and phenotypes assessed, a Granada pigment or SBCB score ≥ 2 captured more than 90% of EOD isolates with excellent inter-rater reliability. High enzyme activity of hyaluronidase was observed in 16% (36/229) of the invasive GBS isolates and notably, in one case of stillbirth. Hyaluronidase activity was also significantly higher in GBS isolates obtained from pregnant/postpartum individuals versus the stillbirth or neonatal invasive isolates (p < 0.001). Sequencing analysis found that abx1 (g.T106I), stk1 (g.T211N), stp1 (g.K469R) and covS (g.V343M) variants were present significantly more often in the higher (Granada pigment score ≥ 2) versus lower pigmented isolates (p < 0.001, each variant). Among the 203 higher Granada pigment scoring isolates, 22 (10.8%) isolates had 3 of the four sequence variants and 10 (4.9%) had 2 of the four sequence variants. Although heterogeneity in GBS virulence factor expression was observed, the vast majority were more highly pigmented and contained several common sequence variants in genes regulating pigment synthesis. High activity of hyaluronidase may increase risk for stillbirth and invasive disease in pregnant or postpartum individuals. Our findings suggest that testing for GBS pigmentation and hyaluronidase may, albeit imperfectly, identify pregnant people at risk for invasive disease and represent a step towards a personalized medical approach for the administration of intrapartum antibiotic prophylaxis.

Do plasmids containing heavy metal resistance genes play a role in neonatal sepsis and invasive disease caused by Klebsiella pneumoniae and Klebsiella variicola?

Introduction. Klebsiella species are some of those most implicated in neonatal sepsis. However, many isolates from infections appear unremarkable; they are generally susceptible to antibiotics and often of sporadic types not associated with virulence.Hypothesis/Gap Statement. Investigation is needed to identify if such isolates have virulence characteristics.Aim. To sequence multiple isolates of a range of types from cases of neonatal invasive disease to identify elements that may explain their virulence, and to determine if such elements are more common among these isolates than generally.Methodology. In total, 14 isolates of K. pneumoniae/K. variicola belonging to 13 distinct types from blood or CSF from neonatal infections were sequenced using long-read nanopore technology. PCR assays were used to screen a general set of isolates for heavy metal resistance genes arsC, silS and merR.Results. Overall, 12/14 isolates carried one or more plasmids. Ten carried a large plasmid (186 to 310 kb) containing heavy metal resistance genes associated with hypervirulence plasmids, with most (nine) carrying genes for resistance to copper, silver and one other heavy metal (arsenic, tellurite or mercury), but lacking the genes encoding capsule-upregulation and siderophores. Most isolates (9/14) lacked any additional antibiotic resistance genes other than those intrinsic in the species. However, a representative of an outbreak strain carried a plasmid containing bla CTX-M-15, qnrS1, aac3_IIa, dfrA17, sul1, mph(A), tet(A), bla TEM1B and aadA5, but no heavy metal resistance genes. arsC, silS and merR were widely found among 100 further isolates screened, with most carbapenemase-gene-positive isolates (20/27) carrying at least one.Conclusion. Plasmids containing heavy metal resistance genes were a striking feature of isolates from neonatal sepsis but are widely found. They share elements in common with virulence and antibiotic resistance plasmids, perhaps providing a basis from which such plasmids evolve.

Population genomics of Group B Streptococcus reveals the genetics of neonatal disease onset and meningeal invasion

Group B Streptococcus (GBS), or Streptococcus agalactiae, is a pathogen that causes preterm births, stillbirths, and acute invasive neonatal disease burden and mortality. Here, we investigate bacterial genetic signatures associated with disease onset time and meningeal tissue infection in acute invasive neonatal GBS disease. We carry out a genome-wide association study (GWAS) of 1,338 GBS isolates from newborns with acute invasive disease; the isolates had been collected annually, for 30 years, through a national bacterial surveillance program in the Netherlands. After controlling for the population structure, we identify genetic variation within noncoding and coding regions, particularly the capsule biosynthesis locus, statistically associated with neonatal GBS disease onset time and meningeal invasion. Our findings highlight the impact of integrating microbial population genomics and clinical pathogen surveillance, and demonstrate the effect of GBS genetics on disease pathogenesis in neonates and infants.

Variation of invasive neonatal GBS disease across the regions

Group B streptococcus (GBS) emerged in the 1960s as the leading cause of neonatal disease in the USA,1 and yet the reason for its emergence is unknown. Possible reasons are past underdiagnosis or a change in the population structure of GBS.2 Intrapartum antibiotic prophylaxis (IAP) was recommended as the prevention strategy for early-onset invasive GBS (EOGBS),3 and was adopted by various high-income countries. As a result, a substantial decline in the incidence of neonatal disease was observed.