Community-acquired intracranial suppurative infections: A 15-year report

Phenomics and genomic features of Enterococcus avium IRMC1622a isolated from a clinical sample of hospitalized patient

BACKGROUND

Enterococcus avium (E. avium) is a Gram-positive nosocomial pathogen that is commonly isolated from the alimentary tract. The objective of this functional genomics study was to identify the resistant genes by analyzing the genome of E. avium IRMC1622a, a type of bacteria found in feces collected from a patient at a Saudi Arabian tertiary hospital.

METHODS

The bacterial strain IRMC1622a was identified by 16 S rRNA sequencing as Enterococcus sp. The resistance phenomics were performed using VITEK® 2, and morphological analysis was achieved using a scanning electron microscope (SEM). Finally, the whole bacterial genome of the bacterial strain IRMC1622a was subjected to sequencing during October 2023 using Oxford Nanopore long-read sequencing technology, and mining for resistant genes.

RESULTS

The results of antimicrobial resistant phenomics indicated that the IRMC1622a strain was sensitive to all tested antimicrobial agents except for erythromycin, and the same result was confirmed by genomic analysis in addition to other classes of antibiotics. SEM showed E. avium IRMC1622a is ovoid shape, in single cells (L 1.2797 ± 0.1490 µm), in pairs (L 1.7333 ± 0.1054 µm), and in chains (L 2.44033 ± 0.1978 µm). The E. avium IRMC1622a genome has 14 (in CARD) antimicrobial resistance genes that were identified with several mechanisms of antimicrobial resistance, such as the efflux pump and conferring antibiotic resistance. The present study revealed that the E. avium IRMC1622a genome contains a high number of genes associated with virulence factors, and 14 matched pathogenic protein families and predicted as human pathogen (probability score 0.855). We report two (ISEnfa4 and ISEfa5) mobile genetic elements for the first time in the E. avium genome.

CONCLUSIONS

The study concludes that E. avium IRMC1622a is susceptible to all tested antibacterials except erythromycin. The IRMC1622a has 14 genes encoding antimicrobial resistance mechanisms, including the efflux pump and conferring antibiotic resistance. This could indicate a potential rise in E. avium resistance in healthcare facilities. These observations may raise concerns regarding E. avium resistance in healthcare. We need more research to understand the pathophysiology of E. avium, which leads to hospital-acquired infections.

Non-faecium non-faecalis enterococci: a review of clinical manifestations, virulence factors, and antimicrobial resistance

SUMMARYEnterococci are a diverse group of Gram-positive bacteria that are typically found as commensals in humans, animals, and the environment. Occasionally, they may cause clinically relevant diseases such as endocarditis, septicemia, urinary tract infections, and wound infections. The majority of clinical infections in humans are caused by two species: Enterococcus faecium and Enterococcus faecalis. However, there is an increasing number of clinical infections caused by non-faecium non-faecalis (NFF) enterococci. Although NFF enterococcal species are often overlooked, studies have shown that they may harbor antimicrobial resistance (AMR) genes and virulence factors that are found in E. faecium and E. faecalis. In this review, we present an overview of the NFF enterococci with a particular focus on human clinical manifestations, epidemiology, virulence genes, and AMR genes.

Unusual intracranial suppuration: illustrative cases

BACKGROUND

Intracranial suppuration (ICS) is a rare complication that can arise from various disease processes and is composed of brain abscess, extradural empyema, and subdural empyema. Although significant progress has been achieved with antibiotics, neuroimaging, and neurosurgical technique, ICS remains a serious neurosurgical emergency. An uncommon presentation of ICS is sterile ICS, which has yet to be fully elucidated by clinicians. The authors present 2 cases of unusual sterile ICS: a sterile subdural empyema and a sterile brain abscess.

OBSERVATIONS

Both patients underwent surgical treatment consisting of craniotomy to evacuate the pus collection. The blood cultures from both the patients, the collected empyema, and the thick capsule from the brain abscess were sterile. However, the necrotic brain tissue surrounding the abscess contained inflammatory cells. The authors’ review of the literature emphasizes the rarity of sterile ICS and substantiates the necessity for additional studies to explore this field.

LESSONS

Sterile ICS is a disease entity that warrants further investigation to determine appropriate treatment to improve patient outcomes. This study highlights the paucity of data available regarding sterile ICS and supports the need for future studies to uncover the etiology of sterile ICS to better guide management of this condition.

Management and Outcomes of Paediatric Intracranial Suppurations in Low- and Middle-Income Countries: A Scoping Review

Introduction: Intracranial suppurations account for a significant proportion of intracranial masses in low- and middle-income countries (LMICs), particularly among children. The development of better imaging equipment, antibiotics, and surgical techniques has enabled significant progress in detecting and treating intracranial abscesses. However, it is unclear whether these advances are accessible and utilised by LMICs. In this review, we aimed to describe the landscape of paediatric intracranial suppurations in LMICs. Methods: This scoping review was conducted using the Arksey and O'Malley framework. MEDLINE, EMBASE, WHO Global Index Medicus, AJOL and Google scholar were searched for relevant articles from database inception to January 18th, 2021. Publications in English and French were included. Results: Of the 1,011 records identified, 75 were included. The studies, on average, included 18.8 (95% CI = 8.4-29.1) children (mean age: 8.2 years). Most children were male (62.2%, 95% CI = 28.7-95.7%). Intracranial suppurations were most commonly (46.5%) located in the supratentorial brain parenchyma. The most prevalent causative mechanism was otitis (37.4%) with streptococcus species being the most common causative organism (19.4%). CT scan (71.2%) was most commonly used as a diagnostic tool and antibiotics were given to all patients. Symptoms resolved in 23.7% and improved in 15.3% of patients. The morbidity rate was 6.9%, 18.8% of patients were readmitted, and the mortality rate was 11.0%. Conclusion: Most intracranial suppurations were complications of preventable infections and despite MRI being the gold standard for detecting intracranial suppurations, CT scans were mostly used in LMICs. These differences are likely a consequence of inequities in healthcare and have resulted in a high mortality rate in LMICs.

Application of combined cerebrospinal fluid physicochemical parameters to detect intracranial infection in neurosurgery patients

Routine test of cerebrospinal fluid (CSF), such as glucose concentrations, chloride ion, protein and leukocyte, as well as color, turbidity and clot, were important indicators for intracranial infection. However, there were no models to predict the intracranial infection with these parameters. We collected data of 221 cases with CSF positive-culture and 50 cases with CSF negative culture from January 1, 2016 to December 31, 2018 in the First Affiliated Hospital of Nanchang University, China. SPSS17.0 software was used to establish the model by adopting seven described indicators, and P < 0.05 was considered as statistically significant. Meanwhile, 40 cases with positive-culture and 10 cases with negative-culture were selected to verify the sensitivity and specificity of the model. The results showed that each parameter was significant in the model establishment (P < 0.05). To extract the above seven parameters, the interpretation model C was established, and C = 0.952–0.183 × glucose value (mmol/L) - 0.024 × chloride ion value (mmol/L)- 0.000122 × protein value (mg/L) - 0.0000859 × number of leukocytes per microliter (× 10⁶/L) + 1.354 × color number code + 0.236 × turbidity number code + 0.691 × clot number code. In addition, the diagnostic sensitivity and specificity of the model were 85.0 and 100%, respectively. The combining application of seven physicochemical parameters of CSF might be of great value in the diagnosis of intracranial infection for adult patients.

Complete genome sequence of bile-isolated Enterococcus avium strain 352

Background

Enterococcus avium is a Gram-positive pathogenic bacterium belonging to the family Enterobacteriaceae. E. avium can cause bacteremia, peritonitis, and intracranial suppurative infection. However, the mechanism of its pathogenesis and its adaptation to a special niche is still unclear.

Results

In this study, the E. avium strain 352 was isolated from human bile and whole genome sequencing was performed. The E. avium strain 352 consists of a circular 4,794,392 bp chromosome as well as an 87,705 bp plasmid. The GC content of the chromosome is 38.98%. There are 4905 and 99 protein coding sequences in the chromosome and the plasmid, respectively. The genome of the E. avium strain 352 contains number of genes reported to be associated with bile adaption, including bsh, sbcC, mutS, nifI, galU, and hupB. There are also several virulence-associated genes including esp, fss1, fss3, ecbA, bsh, lap, clpC, clpE, and clpP.

Conclusions

This study demonstrates the presence of various virulence factors of the E. avium strain 352, which has the potential to cause infections. Moreover, the genes involved in bile adaption might contribute to its ability to live in bile. Further comparative genomic studies would help to elucidate the evolution of pathogenesis of E. avium.

Cerebral Epidural Abscess Secondary to Blastomyces Masquerading as an Epidermoid Tumor

There have been infrequent reports of isolated central nervous system blastomycosis. We report a case of intracranial epidural abscess secondary to Blastomyces dermatitidis in a patient residing in Rhode Island with a history of remote travel to an endemic area. The clinical, radiographic, and pathologic features of this unique case are reviewed.