Neonatal Meningitis and Septicemia Caused by Multidrug-Resistant Elizabethkingia anophelis Identified by 16s Ribosomal RNA: An Emerging Threat

Central Line-Associated Bloodstream Infection Due to Elizabethkingia anophelis: Case Report and Literature Review on Pediatric Infections

Elizabethkingia anophelis is an opportunistic pathogen causing lifethreatening infections in humans, particularly in immunocompromised patients, neonates and the elderly. We report a case of central line-associated bloodstream infection by E. anophelis in a 2.5-year-old girl with acute lymphoblastic leukemia successfully treated with a combination of piperacillin/tazobactam and amikacin. The literature was also reviewed on pediatric infections caused by E. anophelis, focusing on clinical manifestations, underlying medical conditions, treatment and outcome. Accurate identification with MALDI-TOF, or using molecular techniques, is of the utmost importance because treatment and prognosis differ depending on the species. Considering that E. anophelis is multiresistant to antibiotics and that inappropriate antimicrobial therapy is an independent risk factor for mortality, the early, accurate identification of bacterial species and prompt effective treatment are essential to achieve optimal therapeutic outcomes.

Successful Eradication of a Highly Resistant Elizabethkingia anophelis Species in a Premature Neonate With Bacteremia and Meningitis

Elizabethkingia anophelis is a Gram-negative bacillus that can exhibit highly resistant phenotypes against most antibiotics with evidence of efficacy and safety in the neonatal population. Given the limited antimicrobial options, clinicians may be forced into challenging treatment scenarios when faced with central nervous system infections in premature neonates caused by E. anophelis . We report a case of successful treatment of hospital-acquired meningitis and bacteremia caused by E. anophelis at 11 days of life in a male infant born at 29 weeks, 1 day gestation and birth weight of 1.41 kg. Therapy consisted of vancomycin, dose adjusted to maintain goal troughs of 15-20 mg/L, and rifampin 10 mg/kg/dose every 12 hours, with ciprofloxacin 15 mg/kg/dose every 12 hours and trimethoprim/sulfamethoxazole 5 mg/kg/dose every 12 hours added due to antimicrobial susceptibilities and unsatisfactory response, for a total of 21 days. Following initiation of this multidrug regimen, repeat cultures were negative, laboratory parameters improved [with exception of elevated cerebrospinal fluid (CSF) white blood cell count], the patient remained otherwise stable, and there were no adverse effects noted from therapy. Complications after treatment included the requirement of bilateral hearing aids and the development of hydrocephalus necessitating ventriculoperitoneal shunt placement. To our knowledge, we report the first case of meningitis in a premature neonate initially identified as E. anophelis in the United States treated with this regimen which led to successful microbiologic eradication with no antimicrobial safety concerns.

Phylogenomics analysis of multidrug-resistant Elizabethkingia anophelis in industrial wastewater treatment plant

AIMS

This study investigated the phylogenetic relatedness of multidrug-resistant Elizabethkingia anophelis recovered from an industrial wastewater treatment plant (WWTPi).

METHODS AND RESULTS

The wastewater samples were plated in brain heart infusion agar (4 mg/L ceftazidime, 8 mg/L meropenem, and 2 mg/L polimixin). Four isolates recovered from four stages of WWTPi (influent, aeration, decantation, and treated effluent) were identified and evaluated of susceptibility profiles in the VITEK 2 system. These strains identified as E. meningoseptica were confirmed to be E. anophelis by whole genomic sequencing (Miseq-Illumina) and showed antimicrobial resistance genes of β-lactams, aminoglycosides, and tetracycline's classes. The ribosomal multilocus sequence typing showed that they belong to the rST 65620 together with clinical strains. The phylogenomic tree revealed the similarity of our strains to those belonging to sublineage 11 and the single nucleotide polymorphism analysis confirmed that they belong to a single clade.

CONCLUSIONS

To the best of our knowledge, this is the first study reporting the persistence of multidrug-resistant E. anophelis sublineage 11 along the wastewater treatment.

Genomic and phylogenetic characterization of Elizabethkingia anophelis strains: The first two cases of life-threatening infection in Japan

OBJECTIVE

Elizabethkingia anophelis causes meningitis, bloodstream infections, and respiratory infections in immunocompromised individuals. We examined two E. anophelis strains isolated from the first life-threatening cases caused by this species in Japan to determine the phylogenetic origin and genomic features of them.

METHODS

We performed whole genome-based analysis to clarify the genetic relationship for the two strains (EK0004 and EK0079) and Elizabethkingia sp. strains isolated from worldwide and to characterize the genomic features such as the prevalence of virulence- and antimicrobial resistance (AMR)-related genes.

PATIENTS

A 29-year-old man with hepatosplenic T-cell lymphoma and a 52-year-old man with systemic lupus erythematosus developed fatal bacteremia and meningitis due to E. anophelis, respectively.

RESULTS

Two strains, EK0004 and EK0079, were genetically different but most closely related to the strains isolated from the largest outbreak in Wisconsin, USA from 2015 to 2016, and the strain isolated from cerebrospinal fluid of a patient in Florida, USA in 1982, respectively. The two strains contained AMR-related genes such as those encoding for an extended-spectrum β-lactamase and multiple metallo-β-lactamases and several virulence-related genes such as capsular polysaccharide synthesis gene clusters.

CONCLUSIONS

Although further functional analyses are required to understand the virulence of these clones, these finding suggests that enough caution of E. anophelis infection in immunocompromised patients is required since the number of infections by this species is increasing outside Japan.

Population dynamics of Brachionus calyciflorus driven by the associated natural bacterioplankton

Zooplankton provides bacteria with a complex microhabitat richen in organic and inorganic nutrients, and the bacteria community also changes the physiochemical conditions for zooplankton, where the symbiotic relationship between them plays an important role in the nutrient cycle. However, there are few studies on the effect of associated bacteria on the population dynamics of rotifers. In order to make clear their relationships, we reconstructed the associated bacterial community in Brachionus calyciflorus culture, and examined the life history and population growth parameters, and analyzed the diversity and community composition of the associated bacteria at different growth stages of B. calyciflorus. The results showed that the addition of bacteria from natural water can promote the population growth and asexual reproduction of B. calyciflorus, but has no significant effect on sexual reproduction, exhibited by the improvement of its life expectancy at hatching, net reproduction rates and intrinsic growth rate, no significant effects on the generation time and mixis ratio of offspring. It was found that the B. calyciflorus-associated bacterial community was mainly composed of Proteobacteria, Bacteroidota, Actinobacteriota, Cyanobacteria and Firmicutes. Through correlation network analysis, the members of Burkholderiales, Pseudomonadales, Micrococcales, Caulobacterales and Bifidobacteriales were the keystone taxa of B. calyciflorus-associated bacteria. In addition, the relative abundance of some specific bacteria strains increased as the population density of B. calyciflorus increased, such as Hydrogenophaga, Acidovorax, Flavobacterium, Rheinheimera, Novosphingobium and Limnobacter, and their relative abundance increased obviously during the slow and exponential phases of population growth. Meanwhile, the relative abundance of adverse taxa (such as Elizabethkingia and Rickettsiales) decreased significantly with the increase in rotifer population density. In conclusion, the closely associated bacteria are not sufficient for the best growth of B. calyciflorus, and external bacterioplankton is necessary. Furthermore, the function of keystone and rare taxa is necessary for further exploration. The investigation of the symbiotic relationship between zooplankton-associated bacterial and bacterioplankton communities will contribute to monitoring their roles in freshwater ecosystems, and regulate the population dynamics of the micro-food web.

Crystal structures of glutamyl-tRNA synthetase from Elizabethkingia anopheles and E. meningosepticum

Elizabethkingia bacteria are globally emerging pathogens that cause opportunistic and nosocomial infections, with up to 40% mortality among the immunocompromised. Elizabethkingia species are in the pipeline of organisms for high-throughput structural analysis at the Seattle Structural Genomics Center for Infectious Disease (SSGCID). These efforts include the structure-function analysis of potential therapeutic targets. Glutamyl-tRNA synthetase (GluRS) is essential for tRNA aminoacylation and is under investigation as a bacterial drug target. The SSGCID produced, crystallized and determined high-resolution structures of GluRS from E. meningosepticum (EmGluRS) and E. anopheles (EaGluRS). EmGluRS was co-crystallized with glutamate, while EaGluRS is an apo structure. EmGluRS shares ∼97% sequence identity with EaGluRS but less than 39% sequence identity with any other structure in the Protein Data Bank. EmGluRS and EaGluRS have the prototypical bacterial GluRS topology. EmGluRS and EaGluRS have similar binding sites and tertiary structures to other bacterial GluRSs that are promising drug targets. These structural similarities can be exploited for drug discovery.

Elizabethkingia anophelis: An Important Emerging Cause of Neonatal Sepsis and Meningitis in China

Elizabethkingia anophelis, originally isolated from the midgut of Anopheles gambiae in 2011, is an important cause of sepsis in adults and children and meningitis in newborns, with several reported outbreaks worldwide. Accumulating molecular biological and whole-genome sequencing (WGS) evidence suggests that E. anophelis is the major human pathogen belonging to the genus Elizabethkingia. The source of infection, routes of transmission and pathogenicity of E. anophelis are unclear and should be better understood as the bacterium is capable of causing sepsis and meningitis in newborns, with complications and high mortality rates. Here, we describe two healthy neonates who developed meningitis caused by Elizabethkingia infection. Initial conventional laboratory results revealed that the pathogen was E. meningoseptica; metagenomic findings later confirmed it as E. anophelis. We also summarize reported E. anophelis infections among newborns in China and elsewhere and describe the clinical, pathogenic and genetic characteristics of this bacillus.