Extrinsic allergic alveolitis (hypersensitivity pneumonitis) caused by Sphingobacterium spiritivorum from the water reservoir of a steam iron

An unusual cause of pyrexia of unknown origin with sepsis: A diagnostic challenge

Sphingobacterium species are ubiquitous and are abundant in nature and rarely involved in causing human infections. A 62-year-old man presented with recurrent episodes of high fever up to 40 ​°C accompanied by rigors, sweating, and malaise for the past 4 weeks. After a thorough workup, only elevated C-reactive protein with a leucocytosis was evident. Blood culture showed growth of Gram-negative bacilli which was identified as spingobacterium spiritivorum. Although S. spiritivorum is rare, with limited cases reported in the literature, it must be considered as a causative organism in patients with persistent fevers with sepsis.

Scrub Typhus Complicated by Rare Human Pathogen Sphingobacterium spiritivorum

Sphingobacterium spiritivorum is a rare cause of human infections worldwide. After reviewing the literature, we could find only eight case reports to date. The majority of cases were of cellulitis and septicemia. Most of these patients were immunocompromised and the recovery rate was lesser. We present a case of a young female diagnosed with scrub typhus complicated by acute respiratory distress syndrome who developed septicemia and septic shock due to S. spiritivorum. She was managed with sensitive antibiotic levofloxacin, clinically improved, and discharged in satisfactory condition.

A cross sectional study on airborne inhalable microorganisms, endotoxin, and particles in pigeon coops - Risk assessment of exposure

Pigeon breeding is associated with symptoms of the airways. The aim of this study is to illuminate the bacteriological and toxicological characteristics of airborne dust in pigeon coops. Airborne dust was sampled in 31 urban pigeon coops with homing and fancy pigeons, and following the dust was characterized. In total 141 different bacterial species were identified using MALDI-TOF MS, and of these 11 species are classified in risk group 2. Of the cultivable bacteria, Staphylococcus equorum was present in the highest concentration. Microorganisms in the dust were able to form biofilm, and the amount correlated positively with the number of bacteria. Next generation sequencing showed 180 genera with Acinetobacter in highest reads. On average 999 ± 225 ZOTUs were observed per sample with a Shannon-Wiener biodiversity index of 6.17 ± 0.24. Of the identified species the following have previously been suggested as causative agents of extrinsic allergic alveolitis: Alcaligenes faecalis, Bacillus subtilis, Pantoea agglomerans, Sphingobacterium spiritivorum, Thermoactinomyces sp., and Streptomyces albus. Staphylococcus was present on particles with sizes between 1.1 and > 7.0 μm with a geometric mean diameter of particles on 4.7 ± 1.1 μm. Concentrations of airborne endotoxin and dust were elevated compared to references, and the geometric mean concentrations were 102 EU/m³ and 1.07 mg dust/m³, respectively. Upon exposure to the airborne dust human granulocytes produced Reactive Oxidative Species during the first 5 min, and then no further reaction was observed. The concentrations of bacteria in general, Staphylococcus spp., and endotoxin and biodiversity were associated significantly with season, temperature and/or relative humidity, but not with type or density of pigeons. The bacterial composition and biodiversity indices were not affected by type of pigeon. In conclusion, the exposure to bacteria and endotoxin in pigeon houses should not be neglected in the evaluation of causative agents of airways symptoms among pigeon breeders.

NKT Cells Contribute to the Control of Microbial Infections

Innate (-like) T lymphocytes such as natural killer T (NKT) cells play a pivotal role in the recognition of microbial infections and their subsequent elimination. They frequently localize to potential sites of pathogen entry at which they survey extracellular and intracellular tissue spaces for microbial antigens. Engagement of their T cell receptors (TCRs) induces an explosive release of different cytokines and chemokines, which often pre-exist as constitutively expressed gene transcripts in NKT cells and underlie their poised effector state. Thus, NKT cells regulate immune cell migration and activation and subsequently, bridge innate and adaptive immune responses. In contrast to conventional T cells, which react to peptide antigens, NKT cells recognize lipids presented by the MHC class I like CD1d molecule on antigen presenting cells (APCs). Furthermore, each NKT cell TCR can recognize various antigen specificities, whereas a conventional T lymphocyte TCR reacts mostly only to one single antigen. These lipid antigens are either intermediates of the intracellular APC`s-own metabolism or originate from the cell wall of different bacteria, fungi or protozoan parasites. The best-characterized subset, the type 1 NKT cell subset expresses a semi-invariant TCR. In contrast, the TCR repertoire of type 2 NKT cells is diverse. Furthermore, NKT cells express a panoply of inhibitory and activating NK cell receptors (NKRs) that contribute to their primarily TCR-mediated rapid, innate like immune activation and even allow an adaption of their immune response in an adoptive like manner. Dueto their primary localization at host-environment interfaces, NKT cells are one of the first immune cells that interact with signals from different microbial pathogens. Vice versa, the mutual exchange with local commensal microbiota shapes also the biology of NKT cells, predominantly in the gastrointestinal tract. Following infection, two main signals drive the activation of NKT cells: first, cognate activation upon TCR ligation by microbial or endogenous lipid antigens; and second, bystander activation due to cytokines. Here we will discuss the role of NKT cells in the control of different microbial infections comparing pathogens expressing lipid ligands in their cell walls to infectious agents inducing endogenous lipid antigen presentation by APCs.

Assessment and Management of Occupational Hypersensitivity Pneumonitis

The diagnosis and treatment of occupational hypersensitivity pneumonitis (OHP) remain complex and challenging in the absence of diagnostic gold standards or clinical guidelines. This review provides an update of the recent literature regarding the different presentations of OHP and the diagnostic yield and value of the diagnostic tests currently available, which include occupational and medical history, laboratory tests (serum-specific immunoglobulins, environmental sampling), imaging, bronchoalveolar lavage, transbronchial biopsy, transbronchial cryobiopsy, surgical lung biopsy, and specific inhalation challenges. These tools provide a precise differential diagnosis within the framework of interstitial lung diseases. However, among the chronic fibrotic forms, distinguishing OHP from sarcoidosis, nonspecific interstitial pneumonia and idiopathic pulmonary fibrosis remains a diagnostic challenge. Avoidance of exposure is pivotal for OHP management, whereas corticosteroids are fundamental in the pharmacological approach to this disease. In addition, studies describing the long-term benefits of immunosuppressive and antifibrotic agents have increased the use of these treatments in OHP.

Exposure assessment in hypersensitivity pneumonitis: a comprehensive review and proposed screening questionnaire

Hypersensitivity pneumonitis is an immune-mediated inflammatory lung disease characterised by the inhalation of environmental antigens leading to acute and chronic lung injury. Along with suggestive clinical and radiological findings, history and timing of suspected antigen exposure are important elements for diagnostic confidence. Unfortunately, many diagnoses remain tentative and based on vague and imprecise environmental or material exposure histories. To date, there has not been a comprehensive report highlighting the frequency and type of environmental exposure that might lead to or support a more systematic approach to antigen identification. We performed a comprehensive literature review to identify and classify causative antigens and their associated environmental contexts or source materials, with emphasis on the extent of the supportive literature for each exposure type. Eligible publications were those that reported unique inciting antigens and their respective environments or contexts. A clinical questionnaire was then proposed based on this review to better support diagnosis of hypersensitivity pneumonitis when antigen testing or other clinical and radiological variables are inconclusive or incomplete.

The applicability of gene sequencing and MALDI-TOF to identify less common gram-negative rods (Advenella, Castellaniella, Kaistia, Pusillimonas and Sphingobacterium) from environmental isolates

Our aim was to identify less common non-fermenting gram-negative rods during the bioremediation process. Five genera were found: Advenella, Castellaniella, Kaistia, Pusillimonas and Sphingobacterium, for a total of 15 isolates. Therefore, we evaluated the applicability of four methods currently available for bacteria identification: (1) conventional biochemical methods, (2) the VITEK^®-2 system, (3) MALDI-TOF mass spectrometry and (4) 16S rRNA gene sequencing. The biochemical methods and the VITEK^®-2 system were reliable only for the Sphingobacterium isolate and solely at the genus level. Both MALDI-TOF mass spectrometry platforms (Bruker and VITEK^® MS) did not achieve reliable identification results for any of these genera. 16S rRNA gene sequencing identified eight isolates to the species level but not to the subspecies level, when applicable. The remaining seven isolates were reliably identified through 16S rRNA gene sequencing to the genus level only. Our findings suggest that the detection and identification of less common genera (and species) that appeared at certain moments during the bioremediation process can be a challenge to microbiologists considering the most used techniques. In addition, more studies are required to confirm our results.

Cellulitis Complicated with Bacteremia Due to Sphingobacterium Species: A Report of Two Cases and a Literature Review

Sphingobacterium species rarely cause human infection. We herein report two cases of cellulitis complicated with bacteremia due to this genus. The patients, both in their 70s and receiving corticosteroid therapy for their underlying diseases, had antecedent skin injuries in their affected limbs. The patients' symptoms improved promptly and completely with the administration of cefazolin, which did not inhibit the growth of isolated organisms at a concentration of 4 μg/mL.

Sphingobacterium spiritivorum bacteremia due to cellulitis in an elderly man with chronic obstructive pulmonary disease and congestive heart failure: a case report

Background

Sphingobacterium spiritivorum is a glucose non-fermenting Gram-negative rod, formerly classified as one of the Flavobacterium species. It is characterized by a large number of cellular membrane sphingophospholipids. Sphingobacterium species are ubiquitous and isolated from natural environments, such as soil and water. However, they rarely cause infections in humans. Only a limited number of cases have been reported in elderly and immunocompromised patients with underlying diseases and predisposing factors.

Case presentation

An 80-year-old Japanese man with chronic obstructive pulmonary disease and congestive heart failure visited the Kariya Toyota General Hospital, Aichi, Japan with the chief complaint of fever accompanied by chills and left leg pain. At initial presentation, he was distressed and dyspneic. He was febrile (38.8 °C), and his left foot was swollen with reddening and tenderness. We diagnosed him as having cellulitis, and he was hospitalized for antibiotic therapy. Initially, he was treated with intravenously administered cefazolin, but after the isolation of a glucose non-fermenting Gram-negative rod from blood cultures, we decided to switch cefazolin to intravenously administered meropenem on day 4, considering the antibiotic resistance of the causative organism. The causative organism was identified as S. spiritivorum on day 6. His condition gradually stabilized after admission. Meropenem was switched to orally administered levofloxacin on day 12. He was discharged on day 16 and treated successfully without any complications.

Conclusions

Although S. spiritivorum is rare, with limited cases isolated from cellulitis, it should be considered as a causative organism in elderly and immunocompromised patients with cellulitis. Blood cultures are the key to correct diagnosis and appropriate treatment.

Draft Genome Sequences of Two Strains of a Newly Described Species, Sphingobacterium cellulitidis

The draft genome sequences of two strains of a newly described species, Sphingobacterium cellulitidis, have been determined. The type strain originated from cellulitis of a toe of a patient and the other strain from the environment. The sequences will provide the reference genomes of the new Sphingobacterium species.

Sphingobacterium spiritivorum septicaemia associated with cellulitis in a patient with Parkinson's disease

Sphingobacterium spiritivorum, a Gram-negative bacillus, is abundant in nature and is rarely involved in causing human infections. However, it is intrinsically resistant to many commonly administered antibiotics and can thus be a life-threatening microorganism. We describe a case of an 89-year-old Caucasian man who presented with sepsis from S. spiritivorum cellulitis.

Sphingobacterium spiritivorum infection in a patient with end stage renal disease on haemodialysis

Background

Sphingobacterium spiritivorum is a microorganism that is ubiquitously found in the environment. However, it is rarely isolated from human clinical specimens. There are few reports to date of Sphingobacterium spiritivorum causing disease in humans.

Case report

We describe a case of Sphingobacterium spiritivorum infection in a patient on haemodialysis, which to our knowledge, has not been described before. Further testing revealed this strain was sensitive to multiple antimicrobials.

Conclusion

Despite interrupted courses of several antibiotics, our patient clinically made a good recovery and continued to receive haemodialysis.

Monitoring impacts of air pollution: PIXE analysis and histopathological modalities in evaluating relative risks of elemental contamination

Environmental toxicants invariably affect all biological organisms resulting to sufferings ranging from subclinical to debilitating clinical conditions. This novel research aimed to determine the toxic burdens of increased environmental elements in some vital organs/tissues of the wild animals (starling, owl, crow and pigeon), exposed to air polluted environment were assessed using particle induced X-ray emission and histopathological approaches. The presence of significantly elevated amounts of elemental toxicants namely: Aluminum (Al), Chlorine (Cl), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Silicon (Si) and Vanadium (V) from the skin, muscle, lungs, liver and kidney of sampled animals were in concurrence with the observed histopathological changes. The skin of sampled starling, owl, pigeon and crow spotlighted highly significant increase (P < 0.001) in Al, Cl, Mg and Si. Muscle samples with myodegenerative lesions and mineral depositions highlighted substantial augmentation (P < 0.001) in the amount of Al, Fe, Mn, Si and V. The lungs of starling, owl, and pigeon were severely intoxicated (P < 0.001) with increased amount of Al, Fe, K, Mn and Si producing pulmonary lesions of congestion, edema, pneumonitis and mineral debris depositions. Liver samples revealed that the sampled animals were laden with Cl, Fe, Mg, Mn and V with histopathological profound degenerative changes and hepatic necrosis. Kidney sections presented severe tubular degenerative and necrotic changes that may be attributed to increased amounts of Cl and Fe. These current findings implied that the environmental/elemental toxicants and the accompanying lesions that were discerned in the organs/tissues of sampled birds may as well be afflicting people living within the polluted area. Further assessment to more conclusively demonstrate correlations of current findings to those of the populace within the area is encouraged.

The use of specific inhalation challenge in hypersensitivity pneumonitis

PURPOSE OF REVIEW

The diagnosis of hypersensitivity pneumonitis remains a dilemma because of the absence of any characteristic features able to distinguish it from other interstitial lung diseases. We analyze the current role of the specific inhalation challenge (SIC) in the diagnosis of this entity.

RECENT FINDINGS

Few descriptions of the use of SIC for the diagnosis of hypersensitivity pneumonitis have been published in recent years. In fact, hypersensitivity pneumonitis is still diagnosed on the basis of clinical criteria, as there is no agreement on the diagnostic utility of SIC. Two major reviews carried out in the past year have concluded that this test is not standardized and is usually unnecessary; however, a third study found that the test can indeed recreate the symptoms and functional abnormalities in the laboratory, and may therefore be of considerable use in the diagnosis of hypersensitivity pneumonitis.

SUMMARY

Hypersensitivity pneumonitis remains a diagnostic challenge. Given that the main cause of the disease is sensitization and hyper-responsiveness to specific antigens in susceptible individuals, SIC is an obvious candidate as the gold standard for diagnosis of this entity. The present review analyzes the reasons for the test's limited use, assesses its diagnostic utility, and proposes a basis for its standardization.

The first Korean case of Sphingobacterium spiritivorum bacteremia in a patient with acute myeloid leukemia

Sphingobacterium spiritivorum has been rarely isolated from clinical specimens of immunocompromised patients, and there have been no case reports of S. spiritivorum infection in Korea to our knowledge. We report a case of S. spiritivorum bacteremia in a 68-yr-old woman, who was diagnosed with acute myeloid leukemia and subsequently received chemotherapy. One day after chemotherapy ended, her body temperature increased to 38.3℃. A gram-negative bacillus was isolated in aerobic blood cultures and identified as S. spiritivorum by an automated biochemical system. A 16S rRNA sequencing analysis confirmed that the isolate was S. spiritivorum. The patient received antibiotic therapy for 11 days but died of septic shock. This is the first reported case of human S. spiritivorum infection in Korea. Although human infection is rare, S. spiritivorum can be a fatal opportunistic pathogen in immunocompromised patients.

Genome of the pathogen Porphyromonas gingivalis recovered from a biofilm in a hospital sink using a high-throughput single-cell genomics platform

Although biofilms have been shown to be reservoirs of pathogens, our knowledge of the microbial diversity in biofilms within critical areas, such as health care facilities, is limited. Available methods for pathogen identification and strain typing have some inherent restrictions. In particular, culturing will yield only a fraction of the species present, PCR of virulence or marker genes is mainly focused on a handful of known species, and shotgun metagenomics is limited in the ability to detect strain variations. In this study, we present a single-cell genome sequencing approach to address these limitations and demonstrate it by specifically targeting bacterial cells within a complex biofilm from a hospital bathroom sink drain. A newly developed, automated platform was used to generate genomic DNA by the multiple displacement amplification (MDA) technique from hundreds of single cells in parallel. MDA reactions were screened and classified by 16S rRNA gene PCR sequence, which revealed a broad range of bacteria covering 25 different genera representing environmental species, human commensals, and opportunistic human pathogens. Here we focus on the recovery of a nearly complete genome representing a novel strain of the periodontal pathogen Porphyromonas gingivalis (P. gingivalis JCVI SC001) using the single-cell assembly tool SPAdes. Single-cell genomics is becoming an accepted method to capture novel genomes, primarily in the marine and soil environments. Here we show for the first time that it also enables comparative genomic analysis of strain variation in a pathogen captured from complex biofilm samples in a healthcare facility.

Hypersensitivity pneumonitis

Clinical manifestations of hypersensitivity pneumonitis may closely mimic other interstitial lung diseases, and the disease onset is usually insidious. High-resolution computed tomography and bronchoalveolar lavage are the sensitive and characteristic diagnostic tests for hypersensitivity pneumonitis. The relevant antigen to hypersensitivity pneumonitis cannot be identified in up to 20% to 30% of patients. Clinicians should be aware that hypersensitivity pneumonitis must be considered in all cases of interstitial lung disease, and a detailed environmental exposure history is mandatory.

Chronic hypersensitivity pneumonitis

Hypersensitivity pneumonitis (HP) is a complex syndrome caused by the inhalation of environmental antigens. Chronic HP may mimic other fibrotic lung diseases, such as idiopathic pulmonary fibrosis. Recognition of the antigen is important for diagnosis; avoidance of further exposure is critical for treatment. Fibrosis on biopsy or high-resolution computed tomography is a predictor of increased mortality. Additional research is needed to understand why the disease develops only in a minority of exposed individuals and why cases of chronic HP may progress without further antigen exposure.

Significance of specific IgG against sensitizing antigens in extrinsic allergic alveolitis: serological methods in EAA

The aim of our study is to find differences in IgG in sera of potentially exposed and nonexposed individuals and to detect differences in concentrations of specific serum IgG among subjects with and without EAA. Seventy-two patients being followed for suspected interstitial lung disease were included. Specific IgG in sera were established by ImmunoCAP. Serum concentrations of Aspergillus fumigatus, Candida albicans IgG and mixture of moulds IgG were higher in subjects with exposure to relevant inhalation antigens (p<0.05). Patients exposed to parrot and mammal hair mixture had higher serum concentration of specific IgG (p<0.05). Subjects without exposure to mites had lower serum IgG to Dermatophagoides pteronyssinus, Dermatophagoides farinae, Dermatophagoides microceras and Glycophagus domesticus (p<0.05). Higher concentration of serum specific IgG may show previous exposure to this antigen. Even though mite specific IgG are not commonly tested in EAA patients, we suggest their immunomodulatory activity may influence susceptibility to other inhalation antigens.