Insights from the draft genome into the pathogenicity of a clinical isolate of Elizabethkingia meningoseptica Em3

A Case of Community-Acquired Elizabethkingia meningoseptica

Many nosocomial infections commonly arise as a result of contaminated water sources in the hospital setting, such as sinks, air-conditioning systems, ventilation devices, and catheters. Among the microorganisms found in these environments is Elizabethkingia meningoseptica, a gram-negative bacterium first discovered in 1959 by Elizabeth O. King. This bacterium is a rare cause of meningitis, pneumonia, bacteremia, and skin and soft tissue infections in hospital settings. This case report examines a unique community-acquired transmission of E. meningoseptica in a 78-year-old male patient with an extensive medical history who presented with acute fever and confusion coupled with multiple recent falls. Examination and culturing of an open wound on a dry blister of the left lower extremity revealed the presence of E. meningoseptica.

Epidemiology and Characteristics of Elizabethkingia spp. Infections in Southeast Asia

Elizabethkingia spp. is a ubiquitous pathogenic bacterium that has been identified as the causal agent for a variety of conditions such as meningitis, pneumonia, necrotizing fasciitis, endophthalmitis, and sepsis and is emerging as a global threat including in Southeast Asia. Elizabethkingia infections tend to be associated with high mortality rates (18.2–41%) and are mostly observed in neonates and immunocompromised patients. Difficulties in precisely identifying Elizabethkingia at the species level by traditional methods have hampered our understanding of this genus in human infections. In Southeast Asian countries, hospital outbreaks have usually been ascribed to E. meningoseptica, whereas in Singapore, E. anophelis was reported as the main Elizabethkingia spp. associated with hospital settings. Misidentification of Elizabethkingia spp. could, however, underestimate the number of cases attributed to the bacterium, as precise identification requires tools such as MALDI-TOF MS, and particularly whole-genome sequencing, which are not available in most hospital laboratories. Elizabethkingia spp. has an unusual antibiotic resistance pattern for a Gram-negative bacterium with a limited number of horizontal gene transfers, which suggests an intrinsic origin for its multidrug resistance. Efforts to prevent and further understand Elizabethkingia spp. infections and limit its spread must rise to this new challenge.

Neonatal Meningitis with Septicemia by Elizabethkingia meningoseptica: A Case Report

Elizabethkingia is ubiquitary aerobic bacillus abundantly found in the community as well as hospital environments. Elizabethkingia meningoseptica is an emerging nosocomial pathogen with an elemental ability to acclimate and survive in diversified environmental circumstances. Prompt diagnosis and an early therapeutic intervention are preponderant in the management of these infections. We report a case of meningitis with septicemia caused by E. meningoseptica in a 1-day-old outborn neonate. The child was stabilized with anticonvulsants and, based on laboratory findings, the neonate was started on ciprofloxacin in addition to symptomatic management. The child responded well to the treatment and was discharged on day 7 after treatment initiation. Perceptive treatment protocols backed with accurate laboratory evidence remain instrumental to avert unpropitious outcomes while combatting rare multidrug-resistant opportunistic infections.

Elizabethkingia anophelis: Physiologic and Transcriptomic Responses to Iron Stress

In this study, we investigated the global gene expression responses of Elizabethkingia anophelis to iron fluxes in the midgut of female Anopheles stephensi mosquitoes fed sucrose or blood, and in iron-poor or iron-rich culture conditions. Of 3,686 transcripts revealed by RNAseq technology, 218 were upregulated while 112 were down-regulated under iron-poor conditions. Hemolysin gene expression was significantly repressed when cells were grown under iron-rich or high temperature (37°C) conditions. Furthermore, hemolysin gene expression was down-regulated after a blood meal, indicating that E. anophelis cells responded to excess iron and its associated physiological stress by limiting iron loading. By contrast, genes encoding respiratory chain proteins were up-regulated under iron-rich conditions, allowing these iron-containing proteins to chelate intracellular free iron. In vivo studies showed that growth of E. anophelis cells increased 3-fold in blood-fed mosquitoes over those in sucrose-fed ones. Deletion of siderophore synthesis genes led to impaired cell growth in both iron-rich and iron-poor media. Mutants showed more susceptibility to H2O2 toxicity and less biofilm formation than did wild-type cells. Mosquitoes with E. anophelis experimentally colonized in their guts produced more eggs than did those treated with erythromycin or left unmanipulated, as controls. Results reveal that E. anophelis bacteria respond to varying iron concentration in the mosquito gut, harvest iron while fending off iron-associated stress, contribute to lysis of red blood cells, and positively influence mosquito host fecundity.

Comparative genomic analyses reveal diverse virulence factors and antimicrobial resistance mechanisms in clinical Elizabethkingia meningoseptica strains

Three human clinical isolates of bacteria (designated strains Em1, Em2 and Em3) had high average nucleotide identity (ANI) to Elizabethkingia meningoseptica. Their genome sizes (3.89, 4.04 and 4.04 Mb) were comparable to those of other Elizabethkingia species and strains, and exhibited open pan-genome characteristics, with two strains being nearly identical and the third divergent. These strains were susceptible only to trimethoprim/sulfamethoxazole and ciprofloxacin amongst 16 antibiotics in minimum inhibitory tests. The resistome exhibited a high diversity of resistance genes, including 5 different lactamase- and 18 efflux protein- encoding genes. Forty-four genes encoding virulence factors were conserved among the strains. Sialic acid transporters and curli synthesis genes were well conserved in E. meningoseptica but absent in E. anophelis and E. miricola. E. meningoseptica carried several genes contributing to biofilm formation. 58 glycoside hydrolases (GH) and 25 putative polysaccharide utilization loci (PULs) were found. The strains carried numerous genes encoding two-component system proteins (56), transcription factor proteins (187~191), and DNA-binding proteins (6~7). Several prophages and CRISPR/Cas elements were uniquely present in the genomes.

Molecular typing and profiling of topoisomerase mutations causing resistance to ciprofloxacin and levofloxacin in Elizabethkingia species

Objectives

Several Elizabethkingia species often exhibit extensive antibiotic resistance, causing infections associated with severe morbidity and high mortality rates worldwide. In this study, we determined fluoroquinolone susceptibility profiles of clinical Elizabethkingia spp. isolates and investigated the resistance mechanisms.

Methods

In 2017–2018, 131 Elizabethkingia spp. isolates were recovered from specimens collected at tertiary care centers in northern Taiwan. Initial species identification using the Vitek MS system and subsequent verification by 16S rRNA sequencing confirmed the presence of Elizabethkingia anophelis (n = 111), E. miricola (n = 11), and E. meningoseptica (n = 9). Fluoroquinolone susceptibility was determined using the microbroth dilution method, and fluoroquinolone resistance genes were analyzed by sequencing.

Results

Among Elizabethkingia spp. isolates, 91% and 77% were resistant to ciprofloxacin and levofloxacin, respectively. The most prevalent alterations were two single mutations in GyrA, Ser83Ile, and Ser83Arg, detected in 76% of the isolates exhibiting fluoroquinolone MIC between 8 and 128 μg/ml. Another GyrA single mutation, Asp87Asn, was identified in two quinolone-resistant E. miricola strains. None of the isolates had alterations in GyrB, ParC, or ParE. We developed a high-resolution melting assay for rapid identification of the prevalent gyrA gene mutations. The genetic relationship between the isolates was evaluated by random amplified polymorphic DNA PCR that yielded diverse pulsotypes, indicating the absence of any temporal or spatial overlap among the patients during hospitalization.

Conclusion

Our analysis of fluoroquinolone-resistant Elizabethkingia spp. isolates provides information for further research on the variations of the resistance mechanism and potential clinical guidance for infection management.

Emerging Infection with Elizabethkingia Meningoseptica in Neonate. A Case Report

Background

Elizabethkingia meningoseptica are Gram-negative rod bacteria which are commonly found in the environment. The bacteria have also been associated with nosocomial infections, having been isolated on contaminated medical equipment, especially in neonatal wards.

Case report

Here, we present the case of a premature female infant born at 33 weeks’ gestational age, with neonatal meningitis. The onset was marked by fever, in the 5th day of life, while in the Neonatal Intensive Care Unit. The patient was commenced on Gentamicin and Ampicillin, but her clinical condition worsened. Psychomotor agitation and food refusal developed in the 10th day of life, and a diagnosis of bacterial meningitis was made based on clinical and cerebrospinal fluid findings. A strain of Elizabethkingia meningoseptica sensitive to Vancomycin, Rifampicin and Clarithromycin was isolated from cerebrospinal fluid. First-line antibiotic therapy with Meropenem and Vancomycin was adjusted by replacing Meronem with Piperacillin/Tazobactam and Rifampicin. The patient’s clinical condition improved, although some isolated febrile episodes were still present. The cerebrospinal fluid was normalized after 6 weeks of antibiotic treatment, although periventriculitis and tetraventricular hydrocephalus were revealed by imaging studies. Neurosurgical drainage was necessary.

Conclusion

Elizabethkingia meningoseptica can cause severe infection, with high risk of mortality and neurological sequelae in neonates. Intensive care and multidisciplinary interventions are crucial for case management.