Search Results (10)

Maternal vaginal and rectal colonization by Streptococcus agalactiae (group B streptococcus, GBS) is the main risk factor for the development of newborn early-onset GBS disease (GBS-EOD). Much effort is in place for its prevention, including the development of vaccines. Currently, both a hexavalent glycoconjugate GBS vaccine against the most prevalent serotypes and a protein subunit vaccine have completed phase two clinical trials. GBS surveillance in both maternal carriage and neonatal disease is therefore important in establishing the coverage of the potential vaccines and in setting up the basis for pre- and post-marketing surveillance. A single-site study was conducted in the years 2020–2021 on the characteristics of 325 GBS strains (serotype distribution; identification of the alpha-like protein family member; and resistance to macrolides, tetracycline, and high-level gentamicin) isolated from the vaginal/rectal site in women in late pregnancy as well as in seven cases of GBS-EOD and one case of GBS-related stillbirth occurring in the same location and time period. The study indicated that the coverage of the developing vaccines was excellent (97.2% for the hexavalent glycoconjugate vaccine and 98.7% for the alpha-like protein subunit vaccine). However, the detection of the serotypes VI, VII, and IX—not covered by current vaccine formulations—accounting for 3.0% of isolates, as well as of negative alpha-like GBS strains from maternal carriage (1.2%), should be closely monitored over time. The high rates of GBS resistance to erythromycin (33.5%) and to clindamycin (29.5% in maternal carriage and 57.1% in GBS-EOD) was mostly due to the ever-increasing spread of the multidrug-resistant ST-17 subclone of serotype III. This finding, along with the newly emerging high-level gentamicin resistance in carriers (4.0%), mainly in serotype IV strains, poses a threat for the continued effectiveness of antibiotic therapy in invasive disease. Full article

Background: During the outbreak of SARS-CoV-2, strict mitigation measures and national lockdowns were implemented. Our objective was to investigate to what extent the prevalence of some infections in pregnancy was altered during different periods of the COVID-19 pandemic. Methods: This was a single centre retrospective cohort study conducted in the Netherlands on data collected from electronic patient files of pregnant women from January 2017 to February 2021. We identified three time periods with different strictness of mitigation measures: the first and second lockdown were relatively strict; the inter-lockdown period was less strict. The prevalence of the different infections (Group B Streptococcus (GBS)-carriage, urinary tract infections and Cytomegalovirus infection) during the lockdown was compared to the same time periods in previous years (2017–2019). Results: In the first lockdown, there was a significant decrease in GBS-carriage (19.5% in 2017–2019 vs. 9.1% in 2020; p = 0.02). In the period following the first lockdown and during the second, no differences in prevalence were found. There was a trend towards an increase in positive Cytomegalovirus IgM during the inter-lockdown period (4.9% in 2017–2019 vs. 12.8% in 2020; p = 0.09), but this did not reach statistical significance. The number of positive urine cultures did not significantly change during the study period. Conclusions: During the first lockdown there was a reduction in GBS-carriage; further studies are warranted to look into the reason why. Full article

Equine Herpesvirus type 1 (EHV-1) typically causes mild respiratory disease, but it can also cause late-term abortion, neonatal foal death and neurologic disease. Once a horse is infected, the virus concentrates to local lymphoid tissue, where it becomes latent. The virus can be reactivated during times of stress, which can lead to the initiation of devastating outbreaks. Understanding the carriage rate of latent EHV-1 in different geographic regions is essential for managing the disease. The objective of the current study was to estimate the prevalence of latent EHV-1 and compare the frequency of each variant in the submandibular lymph nodes of horses in Virginia. Sixty-three submandibular lymph nodes were collected post-partem from horses submitted to regional labs for necropsy, and qPCR was performed. All samples were negative for the gB gene of EHV-1. The results demonstrated a low apparent prevalence of latent EHV-1 DNA in submandibular lymph nodes in this population of horses in Virginia. Despite this, the mainstay for outbreak prevention and mitigation continues to focus on minimizing risks and using appropriate and diligent biosecurity. Full article

Typhoid fever is caused by Salmonella enterica serovar Typhi (S. Typhi). Around 3–5% of individuals infected become chronic carriers, with the gallbladder (GB) as the predominant site of persistence. Gallstones (GS) aid in the development and maintenance of GB carriage, serving as a substrate to which Salmonellae attach and form a biofilm. This biofilm matrix protects bacteria from the host immune system and environmental stress. This shielded environment is an ideal place for the development of persister cells, a transient phenotype of a subset of cells within a population that allows survival after antibiotic treatment. Persisters can also arise in response to harsh environments such as the GB. Here we investigate if GB conditions affect the number of persisters in a Salmonella population. To simulate the chronic GB environment, we cultured biofilms in cholesterol-coated 96-well plates in the presence of ox or human bile. We then treated planktonic or biofilm Salmonella cultures with high concentrations of different antibiotics. This study suggests that biofilms provide a niche for persister cells, but GB conditions either play no role or have a negative influence on persister formation, especially after kanamycin treatment. The antibiotic target was important, as antimicrobials directed against DNA replication or the cell wall had no effect on persister cell formation. Interestingly, repeated treatment with ciprofloxacin increased the percentage of S. Typhimurium persisters in a biofilm, but this increase was abolished by GB conditions. On the other hand, repeated ciprofloxacin treatment of S. Typhi biofilms in GB conditions slightly increased the fraction of persisters. Thus, while the harsh conditions in the GB would be thought to give rise to increased persisters, therefore contributing to the development of chronic carriage, these data suggest persister cell formation is dampened in this environment. Full article

Group B Streptococcus (GBS) is a leading cause of neonatal infections. The genitourinary and gastrointestinal tract of pregnant women are the main source of transmission to newborns. This work investigated the prevalence and characterized GBS from pregnant women in Rio de Janeiro, Brazil, comparing the periods before (January 2019 to March 2020; 521) and during (May 2020 to March 2021; 285) the COVID-19 pandemic. GBS was detected in 10.8% of anovaginal samples. Considering scenarios before and during the pandemic, GBS colonization rate significantly decreased (13.8% vs. 5.3%; p = 0.0001). No clinical and sociodemographic aspect was associated with GBS carriage (p > 0.05). A total of 80%, 13.8% and 4.6% GBS strains were non-susceptible to tetracycline, erythromycin and clindamycin, respectively. Serotype Ia was the most frequent (47.7%), followed by V (23.1%), II (18.4%), III (7.7%) and Ib (3.1%). An increasing trend of serotypes Ib and V, as well as of antimicrobial resistance rates, and a decreasing trend of serotypes II and III, were observed after the pandemic onset, albeit not statistically significant (p > 0.05). The reduction in GBS colonization rates and alterations in GBS serotypes and resistance profiles during the pandemic were not due to changes in the sociodemographic profile of the population. Considering that control and preventive measures related to the COVID-19 pandemic onset have impacted other infectious diseases, these results shed light on the need for the continuous surveillance of GBS among pregnant women in the post-pandemic era. Full article

Streptococcus agalactiae (Group B Streptococcus, GBS) is a leading cause of neonatal infections. Yet, detailed assessment of the genotypic and phenotypic factors associated with GBS carriage, mother-to-baby transmission, and GBS infection in neonates and adults is lacking. Understanding the distribution of GBS genotypes, including the predominance of different serotypes, antimicrobial resistance (AMR) genes, and virulence factors, is likely to help to prevent GBS diseases, as well as inform estimates of the efficacy of future GBS vaccines. To this end, we set out to characterise GBS isolates collected from pregnant and non-pregnant women in Kaunas region in Lithuania. Whole genome sequences of 42 GBS isolates were analysed to determine multi-locus sequence typing (MLST), the presence of acquired AMR and surface protein genes, and the phylogenetic relatedness of isolates. We identified serotypes Ia (42.9%, 18/42), III (33.3%, 14/42), V (21.4%, 9/42), and a single isolate of serotype Ib. Genomic analyses revealed high diversity among the isolates, with 18 sequence types (STs) identified, including three novel STs. 85.7% (36/42) of isolates carried at least one AMR gene: tetM or tetO (35/42), ermB or lsaC (8/42) and ant6-Ia and aph3-III (2/42). This study represents the first genomic analysis of GBS isolated from women in Lithuania and contributes to an improved understanding of the global spread of GBS genotypes and phenotypes, laying the foundations for future GBS surveillance in Lithuania. Full article

Human cytomegalovirus (HCMV) is a beta-herpesvirus carried by ~80% of adults worldwide. Acute infections are often asymptomatic in healthy individuals but generate diverse syndromes in neonates, renal transplant recipients (RTR), and people with HIV (PWH). The HCMV gene UL111a encodes a homolog of human interleukin-10 (IL-10) that interacts with the human IL-10 receptor. Deep sequencing technologies were used to sequence UL111a directly from 59 clinical samples from Indonesian PWH and Australian RTR, healthy adults, and neonates. Overall, 93% of samples contained more than one variant of HCMV, as defined by at least one nonsynonymous variation. Carriage of these variants differed between neonates and adults, Australians and Indonesians, and between saliva and blood leukocytes. The variant alleles of N41D and S71Y occurred together in Australian RTR and were associated with higher T-cell responses to HCMV pp65. The variant P122S was associated with lower levels of antibodies reactive with a lysate of HCMV-infected fibroblasts. L174F was associated with increased levels of antibodies reactive with HCMV lysate, immediate-early 1 (IE-1), and glycoprotein B (gB) in Australian RTR and Indonesians PWH, suggesting a higher viral burden. We conclude that variants of UL111a are common in all populations and may influence systemic responses to HCMV. Full article

We investigated the molecular epidemiology of Streptococcus agalactiae (Group B Streptococcus, GBS) from carriage in a cohort of pregnant mothers and their respective newborns in a Teaching Hospital in Sri Lanka. GBS vaginal carriage was assessed on pregnant mothers at pre-delivery (n = 250), post-delivery (n = 130), and from peri-rectal swabs of neonates (n = 159) in a prospective study. All colonizing, non-duplicate GBS isolates (n = 60) were analyzed for antimicrobial susceptibilities, capsular serotyping, and whole-genome sequencing (WGS). The percentage of GBS carriage in mothers in the pre-delivery and post-delivery cohorts were 11.2% (n = 28) and 19.2% (n = 25), respectively, and 4.4% (n = 7) in neonates. GBS isolates predominantly belonged to serotype VI (17/60, 28.3%). The isolates spanned across 12 sequence types (STs), with ST1 (24/60, 40%) being the most predominant ST. Concomitant resistance to erythromycin, tetracyclines, and gentamicin was observed in eight strains (13.3%). WGS revealed the presence of antimicrobial resistance genes including ermA (5/60), mefA (1/60), msrD (1/60), and tetLMO (2/60, 28/60, and 1/60, respectively) among 60 strains. The study provides insight into the diversity of vaccine targets of GBS since serotype VI is yet to be covered in the vaccine development program. Full article

Streptococcus agalactiae (Group B Streptococcus, GBS) is an opportunistic pathogen, which asymptomatically colonizes the gastrointestinal and genitourinary tract of up to one third of healthy adults. Nevertheless, GBS carriage in pregnant women may lead to several health issues in newborns causing life threatening infection, such as sepsis, pneumonia or meningitis. Recommended GBS screening in pregnant women significantly reduced morbidity and mortality in infants. Nevertheless, intrapartum antibiotic prophylaxis, recommended following the detection of carriage or in case of lack of a carriage test result for pregnant women who demonstrate certain risk factors, led to the expansion of the adverse phenomenon of bacterial resistance to antibiotics. In our paper, we reviewed some immunogenic GBS proteins, i.e., Alp family proteins, β protein, Lmb, Sip, BibA, FsbA, ScpB, enolase, elongation factor Tu, IMPDH, and GroEL, which possess features characteristic of good candidates for immunodiagnostic assays for GBS carriage detection, such as immunoreactivity and specificity. We assume that they can be used as an alternative diagnostic method to the presently recommended bacteriological cultivation and MALDI. Full article

Many cattle are persistently colonized with Shiga toxin-producing Escherichia coli (STEC) and represent a major source of human infections with human-pathogenic STEC strains (syn. enterohemorrhagic E. coli (EHEC)). Intervention strategies most effectively protecting humans best aim at the limitation of bovine STEC shedding. Mechanisms enabling STEC to persist in cattle are only partialy understood. Cattle were long believed to resist the detrimental effects of Shiga toxins (Stxs), potent cytotoxins acting as principal virulence factors in the pathogenesis of human EHEC-associated diseases. However, work by different groups, summarized in this review, has provided substantial evidence that different types of target cells for Stxs exist in cattle. Peripheral and intestinal lymphocytes express the Stx receptor globotriaosylceramide (Gb₃syn. CD77) in vitro and in vivo in an activation-dependent fashion with Stx-binding isoforms expressed predominantly at early stages of the activation process. Subpopulations of colonic epithelial cells and macrophage-like cells, residing in the bovine mucosa in proximity to STEC colonies, are also targeted by Stxs. STEC-inoculated calves are depressed in mounting appropriate cellular immune responses which can be overcome by vaccination of the animals against Stxs early in life before encountering STEC. Considering Stx target cells and the resulting effects of Stxs in cattle, which significantly differ from effects implicated in human disease, may open promising opportunities to improve existing yet insufficient measures to limit STEC carriage and shedding by the principal reservoir host. Full article