Escherichia coli Causing Neonatal Meningitis During 2001-2020: A Study in Eastern China

From cytokines to chemokines: Understanding inflammatory signaling in bacterial meningitis

Bacterial meningitis is a serious central nervous system (CNS) infection, claiming millions of human lives annually around the globe. The deadly infection involves severe inflammation of the protective sheath of the brain, i.e., meninges, and sometimes also consists of the brain tissue, called meningoencephalitis. Several inflammatory pathways involved in the pathogenesis of meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, Escherichia coli, Haemophilus influenzae, Mycobacterium tuberculosis, Streptococcus suis, etc. are mentioned in the scientific literature. Many in-vitro and in-vivo analyses have shown that after the disruption of the blood-brain barrier (BBB), these pathogens trigger several inflammatory pathways including Toll-Like Receptor (TLR) signaling in response to Pathogen-Associated Molecular Patterns (PAMPs), Nucleotide oligomerization domain (NOD)-like receptor-mediated signaling, pneumolysin related signaling, NF-κB signaling and many other pathways that lead to pro-inflammatory cascade and subsequent cytokine release including interleukine (IL)-1β, tumor necrosis factor(TNF)-α, IL-6, IL-8, chemokine (C-X-C motif) ligand 1 (CXCL1) along with other mediators, leading to neuroinflammation. The activation of another protein complex, nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome, also takes place resulting in the maturation and release of IL-1β and IL-18, hence potentiating neuroinflammation. This review aims to outline the inflammatory signaling pathways associated with the pathogenesis of bacterial meningitis leading to extensive pathological changes in neurons, astrocytes, oligodendrocytes, and other central nervous system cells.

The Promising Effect of Ascorbic Acid and Paracetamol as Anti-Biofilm and Anti-Virulence Agents against Resistant Escherichia coli

Escherichia coli is a major cause of serious infections, with antibiotic resistance rendering many treatments ineffective. Hence, novel strategies to combat this pathogen are needed. Anti-virulence therapy is a promising new approach for the subsequent era. Recent research has examined the impact of sub-inhibitory doses of ascorbic acid and paracetamol on Escherichia coli virulence factors. This study evaluated biofilm formation, protease production, motility behavior, serum resistance, expression of virulence-regulating genes (using RT-PCR), and survival rates in a mouse model. Ascorbic acid significantly reduced biofilm formation, protease production, motility, and serum resistance from 100% in untreated isolates to 22-89%, 10-89%, 2-57%, and 31-35% in treated isolates, respectively. Paracetamol also reduced these factors from 100% in untreated isolates to 16-76%, 1-43%, 16-38%, and 31-35%, respectively. Both drugs significantly down-regulated virulence-regulating genes papC, fimH, ompT_m, stcE, fliC, and kpsMTII. Mice treated with these drugs had a 100% survival rate compared with 60% in the positive control group control inoculated with untreated bacteria. This study highlights the potential of ascorbic acid and paracetamol as anti-virulence agents, suggesting their use as adjunct therapies alongside conventional antimicrobials or as alternative treatments for resistant Escherichia coli infections.

Limitations of current techniques in clinical antimicrobial resistance diagnosis: examples and future prospects

Antimicrobial resistance is a global threat to public health. Without proactive intervention, common infections may become untreatable, restricting the types of clinical intervention that can be undertaken and reversing improvements in mortality rates. Effective antimicrobial stewardship represents one approach to restrict the spread of antimicrobial resistance but relies on rapid and accurate diagnostics that minimise the unnecessary use of antibiotics. This is increasingly a key unmet clinical need. In this paper, we describe existing techniques for the detection of antimicrobial resistance, while examining their drawbacks and limitations. We also discuss emerging diagnostic technologies in the field, and the need for standardisation to allow for swifter and more widespread clinical adoption.

New and old lessons from a devastating case of neonatal E coli meningitis

BACKGROUND

Neonatal Escherichia coli (E coli) meningitis results in significant morbidity and mortality. We present a case of a premature infant with extensive central nervous system (CNS) injury from recurrent E coli infection and the non-traditional methods necessary to identify and clear the infection.

CASE PRESENTATION

The infant was transferred to our institution's pediatric intensive care unit (PICU) after recurrence of E coli CNS infection requiring neurosurgical intervention. He had been treated for early onset sepsis (EOS) with ampicillin and gentamicin for 10 days followed by rapid development of ampicillin-resistant E coli septic shock and meningitis after discontinuation of antibiotics. Sterility of the CNS was not confirmed at the end of 21 days of cefepime therapy and was subsequently followed by recurrent ampicillin-resistant E coli septic shock and CNS infection. Despite 6 weeks of appropriate therapy with sterility of CSF by traditional methods, he suffered from intractable seizures with worsening hydrocephalus. Transferred to our institution, he underwent endoscopic 3rd ventriculostomy with cyst fenestration revealing purulent fluid and significant pleocytosis. An additional 3 weeks of systemic and intraventricular antibiotics with cefepime and tobramycin were given but a significant CNS neutrophil-predominant pleocytosis persisted (average of ∼ 21,000 cells/mm3). Repeated gram stains, cultures, polymerase chain reaction (PCR) testing, and metagenomic next generation sequencing (NGS) testing of CSF were negative for pathogens but acridine orange stain (AO) revealed numerous intact rod-shaped bacteria. After the addition of ciprofloxacin, sterility and resolution of CSF pleocytosis was finally achieved.

CONCLUSION

Neonatal E coli meningitis is a well-known entity but unlike other bacterial infections, it has not proven amenable to shorter, more narrow-spectrum antibiotic courses or limiting invasive procedures such as lumbar punctures. Further, microbiologic techniques to determine CSF sterility suffer from poorly understood limitations leading to premature discontinuation of antibiotics risking further neurologic damage in vulnerable hosts.

The Epidemiology, Management and Therapeutic Outcomes of Subdural Empyema in Neonates with Acute Bacterial Meningitis

Background: Subdural empyema is one of the more serious complications of bacterial meningitis and therapeutic challenges to clinicians. We aimed to evaluate the clinical characteristics, treatment, and outcome of subdural empyema in neonates with bacterial meningitis. Methods: A retrospective cohort study was conducted in two medical centers in Taiwan that enrolled all cases of neonates with subdural empyema after bacterial meningitis between 2003 and 2020. Results: Subdural empyema was diagnosed in 27 of 153 (17.6%) neonates with acute bacterial meningitis compared with cases of meningitis without subdural empyema. The demographics and pathogen distributions were comparable between the study group and the controls, but neonates with subdural empyema were significantly more likely to have clinical manifestations of fever (85.2%) and seizure (81.5%) (both p values < 0.05). The cerebrospinal fluid results of neonates with subdural empyema showed significantly higher white blood cell counts, lower glucose levels and higher protein levels (p = 0.011, 0.003 and 0.006, respectively). Neonates with subdural empyema had a significantly higher rate of neurological complications, especially subdural effusions and periventricular leukomalacia. Although the final mortality rate was not increased in neonates with subdural empyema when compared with the controls, they were often treated much longer and had a high rate of long-term neurological sequelae. Conclusions: Subdural empyema is not uncommon in neonates with acute bacterial meningitis and was associated with a high risk of neurological complications, although it does not significantly increase the final mortality rate. Close monitoring of the occurrence of subdural empyema is required, and appropriate long-term antibiotic treatment after surgical intervention may lead to optimized outcomes.

A live attenuated vaccine to prevent severe neonatal Escherichia coli K1 infections

Preterm birth is currently the leading cause of neonatal morbidity and mortality. Genetic, immunological and infectious causes are suspected. Preterm infants have a higher risk of severe bacterial neonatal infections, most of which are caused by Escherichia coli an in particular E. coli K1strains. Women with history of preterm delivery have a high risk of recurrence and therefore constitute a target population for the development of vaccine against E. coli neonatal infections. Here, we characterize the immunological, microbiological and protective properties of a live attenuated vaccine candidate in adult female mice and their pups against after a challenge by K1 and non-K1 strains of E. coli. Our results show that the E. coli K1 E11 ∆aroA vaccine induces strong immunity, driven by polyclonal bactericidal antibodies. In our model of meningitis, mothers immunized prior to mating transfer maternal antibodies to pups, which protect newborn mice against various K1 and non-K1 strains of E. coli. Given the very high mortality rate and the neurological sequalae associated with neonatal E. coli K1 meningitis, our results constitute preclinical proof of concept for the development of a live attenuated vaccine against severe E. coli infections in women at risk of preterm delivery.

Late-Onset Meningitis in a Preterm Infant Caused by Streptococcus gallolyticus Subsp. Pasteurianus in Saudi Arabia: A Case Report and Literature Review

This report describes the progression of meningitis in a 24-day-old preterm male infant infected with Streptococcus gallolyticus subsp. pasteurianus (SGSP) and its medical care, pathogen detection, antibiotic treatment, and monitoring, ultimately leading to a positive outcome of successful recovery. Neonatal meningitis (NM) is a serious and potentially life-threatening condition, particularly in immunocompromised preterm infants. This report from Saudi Arabia presents a rare case of late-onset neonatal meningitis caused by SGSP in a preterm male infant. The 24-day-old preterm neonate presented with fever, lethargy, poor feeding, and respiratory distress. SGSP was confirmed by cerebral spinal fluid analysis showing the presence of pleocytosis and a low glucose ratio. Prompt antibiotic therapy with intravenous Ampicillin and Cefotaxime led to decreased pleocytosis, and the infant was discharged after 21 days. This report highlights the importance of vigilance, diagnosis, and management of neonatal infections caused by uncommon pathogens such as SGSP. The rarity of SGSP-caused meningitis emphasizes the need to monitor pregnant women for potential transmission and to implement early diagnostic and management strategies. This case report also encompasses a review of recent globally reported cases of neonatal S. gallolyticus infection, highlighting the distinctiveness of this report as the first of its type in Saudi Arabia.

Comparison of Epidemiological Characteristics Between ESBL and Non-ESBL Isolates of Clinically Isolated Escherichia coli from 2014 to 2022: A Single-Center Study

Purpose

This single-center study aims to investigate the epidemiological characteristics of clinically isolated Escherichia coli from 2014 to 2022.

Methods

In vitro drug sensitivity of E. coli to 20 antibiotics was examined using the microbroth dilution method. A total of 7580 clinical E. coli strains were isolated from 2014 to 2022, among which 56.9% were identified as extended spectrum beta-lactamase-producing strains. The data were analyzed using the software WHONET5.6 and the R language platform.

Results

Over the study period, carbapenem resistance rates increased by more than 50% (2022 [1.34%] vs 2014 [0.8%]) and the annual number of isolates showed an upward trend (1264 in 2022 vs 501 in 2014). Drug resistance rates were the highest for penicillin (75-85%) and lowest for imipenem (1%). The resistance rate of strains isolated from male patients and sputum was found to be higher than that of female patients and urine, except for quinolones (p <0.05). The drug resistance rates from high to low were penicillins (75-85%), tetracycline (64%), quinolones (64-67%), sulfamethoxazole (59.3%), cephalosporins (22-72%), aztreonam (34%), chloramphenicol (21%), amikacin (2.8%), colistin (1.4%), meropenem (1.1%), and imipenem (1%). Urine, sputum, and blood accounted for 51%, 16.6%, and 10.6% of the samples, respectively. A greater number of female patients were included more than male patients (4798[63.3%] vs 2782[26.7%]). Patients aged 50-80 accounted for 64.2% of those surveyed.

Conclusion

Carbapenems remain the optimal choice for treating extended spectrum beta-lactamase-producing E. coli infections (sensitivity rate: 98%). Colistin (87.7%) and amikacin (87%) exhibited good antibacterial activities against carbapenem-resistant E. coli. Long-term and continuous epidemiological surveillance of E. coli can facilitate the development of preventive strategies and control policies.

Clinical Features and a Prediction Nomogram for Prognosis in Children with Escherichia coli Meningitis

BACKGROUND

We aimed to build a prediction nomogram for early prediction of poor prognosis in children with Escherichia coli meningitis and analyzed the course of treatment and discharge criteria.

METHODS

Eighty-seven pediatric patients with E coli meningitis were retrospectively recruited from the Children's Hospital of Chongqing Medical University between June 2012 and November 2021. Univariate analysis and binary logistic analysis were used to evaluate the risk factors, and the prediction model was built.

RESULTS

E coli meningitis is more common in children <3 months old in our study (86.2%). Common complications were subdural effusion (39.1%), followed by hydrocephalus (13.8%) and repeated convulsions (12.6%). The mortality rate and sequelae rate of E coli meningitis in children was ∼10.9% and ∼6.3%, respectively. Univariate analysis showed that 13 clinical indicators were associated with poor prognosis of E coli meningitis in children. In binary logistic analysis, risk factors were seizures (P = .032) and the last cerebrospinal fluid glucose content before discharge (P = .002). A graphical nomogram was designed. The area under the receiver operating characteristic curve was 0.913. The Hosmer-Lemeshow test showed that the model was a good fit (P = .648). Internal validation proved the reliability of the prediction nomogram.

CONCLUSIONS

E coli meningitis is more common in children <3 months old in our study. The rate of complications and sequelae are high. The prediction nomogram could be used to assess the risk of poor prognosis in children with E coli meningitis by clinicians.

The Clinical Characteristics, Microbiology and Risk Factors for Adverse Outcomes in Neonates with Gram-Negative Bacillary Meningitis

Background: We aimed to describe the clinical features of Gram-negative bacillary (GNB) meningitis in neonates and investigate the risk factors associated with final adverse outcomes of neonatal GNB meningitis. Methods: From 2003 to 2020, all neonates (aged ≤ 90 days old) with bacterial meningitis who were hospitalized in four tertiary-level neonatal intensive care units (NICUs) of two medical centers in Taiwan were enrolled. Neonates with GNB meningitis were compared with those with Streptococcus agalactiae (group B streptococcus, GBS) meningitis. Results: During the study period, a total of 153 neonates with bacterial meningitis were identified and enrolled. GNB and GBS accounted for 40.5% (n = 62) and 35.3% (n = 54) of all neonatal bacterial meningitis, respectively. In neonates with GNB meningitis, the final mortality rate was 6.5% (4 neonates died); 48 (77.4%) had neurological complications, and 26 (44.8%) of 58 survivors had neurological sequelae at discharge. Although the final outcomes were comparable between neonates with GNB meningitis and those with GBS meningitis, neonates with GNB meningitis were more likely to have more severe clinical manifestations initially and have ventriculomegaly at follow-up. After multivariate logistic regression analysis, neonates with seizure at onset, early onset sepsis, and requirement of surgical intervention for neurological complications were independently associated with final adverse outcomes. Conclusions: GNB meningitis was associated with a high risk of neurological complications and sequelae, although it did not significantly increase the final mortality rate. Close monitoring of the occurrence of neurological complications and advanced therapeutic strategies to optimize the outcomes are urgently needed in the future.

Risk Factors Associated with Multi-Drug Resistance in Neonatal Sepsis Caused by Escherichia coli

BACKGROUND AND OBJECTIVE

An increasing number of cases of neonatal sepsis due to extended-spectrum beta-lactamase (ESBL)-producing multi-drug resistant (MDR) Escherichia coli (E. coli) have been reported worldwide. The aim of this study was to explore the risk factors associated with ESBL-producing MDR E. coli among neonates with culture-confirmed E. coli sepsis and thereby to help selection of appropriate empirical antibiotics.

PATIENTS AND METHODS

All newborn infants with a confirmed pathogen isolated from blood or cerebrospinal fluid (CSF) from 2016 to 2021 were identified and those with E. coli infection were included in this analysis. We compared a group of neonatal patients with ESBL-producing MDR E. coli sepsis (n=69) to a group with ESBL-negative E. coli (n=70) based on antimicrobial susceptibility reports. We used multivariable regression analysis to determine the risk factors associated with ESBL-producing MDR E. coli strains among the neonates with culture-confirmed E. coli sepsis.

RESULTS

ESBL-producing MDR E. coli sepsis was more common in premature infants and newborns with hospital-acquired late-onset sepsis (HALOS). The mortality rate of neonatal sepsis caused by ESBL-producing E. coli was about twice as that of sepsis caused by ESBL-negative E. coli. Antepartum exposure to cephalosporins (OR=25.191, 95% CI: 3.184-199.326, P<0.01) and parenteral nutrition for more than 1 week (OR=4.495, 95% CI: 2.009-10.055, P<0.01) were independent risk factors for neonatal infection with ESBL-producing stains among infants with E. coli sepsis.

CONCLUSION

E. coli remains the most common Gram-negative bacterial pathogen causing neonatal sepsis. A higher proportion of ESBL-producing MDR E. coli is seen in premature infants and those newborns with HALOS and is associated with higher mortality. Antepartum use of cephalosporins and prolonged use of parenteral nutrition may be important factors to consider in the selection of empirical antibiotics for use in neonatal sepsis caused by gram-negative rods prior to the availability of the results of antimicrobial susceptibility.

Glycoconjugate vaccines against antimicrobial resistant pathogens

INTRODUCTION

Antimicrobial resistance (AMR) is responsible for the death of millions worldwide and stands as a major threat to our healthcare systems, which are heavily reliant on antibiotics to fight bacterial infections. The development of vaccines against the main pathogens involved is urgently required as prevention remains essential against the rise of AMR.

AREAS COVERED

A systematic research review was conducted on MEDLINE database focusing on the six AMR pathogens defined as ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli), which are considered critical or high priority pathogens by the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC). The analysis was intersecated with the terms carbohydrate, glycoconjugate, bioconjugate, glyconanoparticle, and multiple presenting antigen system vaccines.

EXPERT OPINION

Glycoconjugate vaccines have been successful in preventing meningitis and pneumoniae, and there are high expectations that they will play a key role in fighting AMR. We herein discuss the recent technological, preclinical, and clinical advances, as well as the challenges associated with the development of carbohydrate-based vaccines against leading AMR bacteria, with focus on the ESKAPE pathogens. The need of innovative clinical and regulatory approaches to tackle these targets is also highlighted.

Be aware of Extended-spectrum β-lactamase-producing Escherichia coli in neonates and Listeria monocytogenes in young children with bacterial meningitis in Japan

Nationwide surveillance of pediatric bacterial meningitis in Japan from 2019 to 2021 revealed two uncommon situations not covered by the recommended empiric treatment that were not rare in Japan, namely, extended-spectrum β-lactamase-producing-producing Escherichia coli in neonates and Listeria monocytogenes in children older than 1 month.

Metabolic and Morphotypic Trade-Offs within the Eco-Evolutionary Dynamics of Escherichia coli

Escherichia coli arbitrarily encompasses facultative anaerobic, rod-shaped bacteria with defined respiratory and fermentative types of metabolism. The species diversification has been further advanced by atypical strains whose features deviate from the essential species-specific morphological and metabolic cutoff. The morphological cutoff is exemplified by bacterial filamentation. E. coli filamentation has been studied from two different perspectives: the first considers filamentation as a result of adaptive strategies and response to stress, while the second is based on findings from the cell division of E. coli's conditional mutants. Another cutoff is represented by E. coli's inability to use citrate as a sole carbon and energy source. In this study, we compared two atypical E. coli strains that belong to the same neuroinvasive ecovar but exhibit either of the two phenotypes that deviate from the species' features. While E. coli RS218 exists in the form of filaments incapable of growth on citrate, strain IHE3034 is represented as normal-sized bacteria able to ferment citrate under oxic conditions in the presence of glucose; in this paper, we show that these two phenotypes result from a bona fide trade-off. With the help of comparative proteomics and metabolomics, we discovered the proteome required for the upkeep of these phenotypes. The metabolic profiles of both strains reveal that under aerobic conditions, RS218 undergoes oxidative metabolism, while IHE3034 undergoes anaerobic respiration. Finally, we show that the use of citrate and filament formation are both linked in a trade-off occurring via a c-di-GMP-dependent phase variation event. IMPORTANCE Aerobic use of citrate and filamentous growth are arbitrary cutoffs for the Escherichia coli species. The strains that exhibit them as stable phenotypes are called atypical. In this study, we compare two atypical neuroinvasive E. coli strains, which alternatively display either of these phenotypes. We present the proteome and metabolome required for the maintenance of filamentous growth and show that anaerobic nitrate respiration is the main requirement for the use of citrate. The fact that the two phenotypes are differentially expressed by each strain prompted us to check if they are part of a trade-off. Indeed, these atypical characters are reversible and result from a c-di-GMP phase variation event. Thus, we revealed hidden links between stable morphological and metabolic phenotypes and provided information about alternative evolutionary pathways for the survival of E. coli strains in various host niches.

Prevalence of Escherichia coli ST1193 Causing Intracranial Infection in Changsha, China

ST1193 is an emerging new virulent and resistant clone among Escherichia coli with a tendency to spread rapidly across the globe. However, the prevalence of intracranial infection-causing E. coli ST1193 is rarely reported. This study aimed at determining the prevalence of E. coli ST1193 isolates, causing intracranial infections in Changsha, central China. A total of 28 E. coli isolates were collected from the cerebrospinal fluid of patients with intracranial infection over a four-year period. All isolates were differentiated using multilocus sequence typing (MLST), and phylogenetic grouping, and tested for antibiotic resistance. MLST analysis showed 11 sequence types (ST) among the 28 E. coli isolates. The most prevalent ST was B2-ST1193 (28.6%, 8/28), followed by B2-ST131 (21.4%, 6/28) and F-ST648 (10.7%, 3/28). Of the eight ST1193 isolates, three carried CTX-M-55, and one carried CTX-M-27. All eight ST1193 isolates were resistant to Ciprofloxacin, showing gyrA1AB/parC4A mutations. Two ST1193 isolates carried the aac(6′)-Ib-cr gene. All ST1193 isolates were recovered from infants with meningitis, with a fatal outcome for one three-month-old infant. ST1193 has emerged as the predominant type of E. coli strain causing intracranial infections in Changsha, China. This study highlights the importance of implementing appropriate surveillance measures to prevent the spread of this emerging public health threat.

Antitumor Activities of tRNA-Derived Fragments and tRNA Halves from Non-pathogenic Escherichia coli Strains on Colorectal Cancer and Their Structure-Activity Relationship

tRNAs purified from non-pathogenic Escherichia coli strains (NPECSs) possess cytotoxic properties on colorectal cancer cells. In the present study, the bioactivity of tRNA halves and tRNA fragments (tRFs) derived from NPECSs are investigated for their anticancer potential. Both the tRNA halves and tRF mimics studied exhibited significant cytotoxicity on colorectal cancer cells, with the latter being more effective, suggesting that tRFs may be important contributors to the bioactivities of tRNAs derived from the gut microbiota. Through high-throughput screening, the EC83 mimic, a double-strand RNA with a 22-nucleotide (nt) 5′-tRF derived from tRNA-Leu(CAA) as an antisense chain, was identified as the one with the highest potency (50% inhibitory concentration [IC₅₀] = 52 nM). Structure-activity investigations revealed that 2′-O-methylation of the ribose of guanosine (Gm) may enhance the cytotoxic effects of the EC83 mimic via increasing the stability of its tertiary structure, which is consistent with the results of in vivo investigations showing that the EC83-M2 mimic (Gm modified) exhibited stronger antitumor activity against both HCT-8 and LoVo xenografts. Consistently, 4-thiouridine modification does not. This provides the first evidence that the bioactivity of tRF mimics would be impacted by chemical modifications. Furthermore, the present study provides the first evidence to suggest that novel tRNA fragments derived from the gut microbiota may possess anticancer properties and have the potential to be potent and selective therapeutic molecules.

IMPORTANCE While the gut microbiota has been increasingly recognized to be of vital importance for human health and disease, the current literature shows that there is a lack of attention given to non-pathogenic Escherichia coli strains. Moreover, the biological activities of tRNA fragments (tRFs) derived from bacteria have rarely been investigated. The findings from this study revealed tRFs as a new class of bioactive constituents derived from gut microorganisms, suggesting that studies on biological functional molecules in the intestinal microbiota should not neglect tRFs. Research on tRFs would play an important role in the biological research of gut microorganisms, including bacterium-bacterium interactions, the gut-brain axis, and the gut-liver axis, etc. Furthermore, the guidance on the rational design of tRF therapeutics provided in this study indicates that further investigations should pay more attention to these therapeutics from probiotics. The innovative drug research of tRFs as potent druggable RNA molecules derived from intestinal microorganisms would open a new area in biomedical sciences.