Hepatocyte Growth Factor has Unique Functions in Keratinocytes that differs from IL-17A and TNF and may contribute to Inflammatory Pathways in Hidradenitis Suppurativa.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that is difficult to control, and its mechanism remains unclear. Hepatocyte growth factor (HGF) has been reported to be significantly upregulated in the serum and skin of HS patients, especially in the lesions with tunnels. In this study, we examined the transcriptome of HGF-treated keratinocytes (KCs) and compared it with genetic profiling of HS lesions. HGF was highly expressed in HS skin, especially in the deep dermis, compared to healthy controls, and its source was mainly fibroblasts. HGF upregulated more genes in KCs than interleukin-17A or tumor necrosis factor-α, and these genes included multiple epithelial-mesenchymal transition (EMT)-related genes. Differentially expressed genes in HGF-stimulated KCs were involved in activation of EMT-related pathways. These HGF-induced genes were significantly upregulated in HS lesions compared to healthy skin and non-lesions and were more strongly associated with HS tunnels. In summary, HGF was highly expressed in HS and induced EMT-related genes in KCs; HGF-induced genes were highly associated with gene profiling of HS with tunnels, suggesting that HGF may be involved in HS tunnel formation via EMT.

Sleep Restfulness in Patients with Obstructive Sleep Apnea Undergoing Continuous Positive Airway Pressure Therapy.

Objective Sleep restfulness is closely associated with mortality. Thus, it is an important sleep-related symptom in the general population. However, it is rarely evaluated in patients with obstructive sleep apnea (OSA) syndrome. The present study examined the importance of sleep restfulness in patients with OSA receiving continuous positive airway pressure (CPAP) therapy. Materials and Methods We administered sleep-related questionnaires, which included items such as subjective sleep duration and sleep restfulness, to 775 patients with OSA receiving CPAP therapy. Sleep restfulness was rated using a 5-point Likert-type scale, with the score of 5 indicating restfulness. Good adherence to CPAP therapy was defined as the use of CPAP therapy for at least 4 h per night in 70% of nights. Results We excluded 105 patients with lacking data. Thus, 670 patients were finally examined. In total, 29 (4.3%), 124 (18.5%), 139 (20.8%), 235 (35.1%), and 143 (14.3%) patients answered restless (1), somewhat restless (2), neither (3), somewhat restful (4), and restful (5) respectively. A total of 467 (69.7%) patients had good adherence to CPAP therapy. Multivariate logistic regression analysis showed that sleep restfulness was independently and positively associated with subjective sleep duration (≥ 7 hours) and good adherence to CPAP therapy. Conclusion Sleep restfulness was associated with subjective sleep duration and good adherence to CPAP therapy in patients with OSA. Favorable outcomes are significantly correlated with good adherence to CPAP therapy. Thus, sleep restfulness can be an indicator of a subtype that has favorable outcomes in patients after CPAP therapy.

Case report: A case of anti-recoverin antibody-positive encephalitis exhibiting Cotard and Capgras delusions that was successfully treated with electroconvulsive therapy.

Recoverin is a neuron-specific calcium-binding protein that is mainly located in the retina and pineal gland. Few reports have described patients with anti-recoverin antibody-positive encephalitis, and no cases of psychosis associated with this encephalitis have been reported. We report a patient with anti-recoverin antibody-positive encephalitis with Cotard and Capgras delusions who was successfully treated with electroconvulsive therapy (ECT). The patient was a 25-year-old woman. She exhibited disorientation, executive function deficits, tremors in the upper limbs, generalized athetoid-like involuntary movements, hallucinations, incontinence, and fever, which led to her admission to our hospital. Upon admission, she complained of Cotard delusions. Various diagnostic tests, including cerebrospinal fluid analysis, antibody screening, and brain imaging, were unremarkable, except for positivity for serum anti-recoverin antibodies, non-specific general slowing on electroencephalography and decreased regional cerebral blood flow (rCBF) in the frontal and occipital lobes, and increased rCBF in the basal ganglia and pons on single-photon emission computed tomography. She was eventually diagnosed with encephalitis positive for anti-recoverin antibodies and treated with immunoglobulins and steroids. Her neurological symptoms improved temporarily, but three months later, psychiatric symptoms, i.e., suicidal thoughts and Cotard and Capgras delusions, were exaggerated. After ECT, her condition significantly improved. In conclusion, the present report suggests that pineal gland dysfunction due to anti-recoverin antibody or its cross-reactivity with neuron-specific calcium-binding proteins may contribute to the neuropsychiatric symptoms observed in anti-recoverin antibody-positive encephalitis and that ECT can be a viable treatment option if immunotherapy proves ineffective. Additionally, decreased rCBF in the prefrontal cortex may be associated with the clinical features of Capgras and Cotard delusions.

[A case of Hashimoto's encephalopathy with acute onset of psychiatric symptoms and diffuse deep white matter lesions on brain MRI].

A 51-year-old man developed acute disturbances in consciousness and psychiatric symptoms one month prior to admission. He was referred and admitted to the Department of Psychiatry of our hospital and transferred to the neurology department because diffuse white matter lesions were found on his brain during MRI. 123I-IMP-SPECT showed extensive cerebral hypoperfusion mainly in the frontal lobes. Anti-Tg, anti-TPO, and anti-NAE antibodies were positive. These findings led to a diagnosis of Hashimoto's encephalopathy. The patient responded to steroid pulse therapy, high-dose steroid therapy, and intravenous immunoglobulin therapy, showing improvement in symptoms and imaging findings. Hashimoto's encephalopathy often presents with MRI findings similar to those of limbic encephalitis, when the patient presents with acute consciousness disturbance and psychiatric symptoms. However, this case showed diffuse white matter lesions, which may be clinically important for the differential diagnosis.

Associations between Nocturnal Hypoxemia and Retinal Nerve Fiber Layer Thinning: The Nagahama Study.

Rationale: There have been meta-analyses that showed reduced retinal nerve fiber layer (RNFL) thickness, which is a surrogate marker of glaucoma, in patients with obstructive sleep apnea (OSA). However, the sample sizes in these reports were small (<300), and the mechanism of RNFL thinning in patients with OSA was not revealed.Objectives: To investigate the relationship of RNFL thickness with nocturnal hypoxemia or hypoxemic burden in a large-scale study.Methods: In this epidemiological study, 8,309 community residents were enrolled. The actigraphy-modified 3% oxygen desaturation index (acti-ODI3%) and cumulative percentage of sleep time with oxygen saturation <90% (acti-CT90) modified by objective sleep duration using actigraphy were measured. The hypoxemic burden is shown as acti-CT90. Circumpapillary RNFL thickness was determined using optical coherence tomography.Results: Multivariable logistic analysis models revealed that an increase in acti-CT90 was significantly associated with mean RNFL thinning after adjusting for several factors in participants without glaucoma diagnosed or treated previously (ß = -0.037; P = 0.009). There were significant differences in mean RNFL thickness among participants stratified according to acti-CT90 (>1.5 vs. ⩽1.5; P = 0.04). Although acti-ODI3% was significantly associated with acti-CT90 (ß = 0.72; P < 0.0001), acti-ODI3% was not significantly associated with mean RNFL thickness in the multivariable logistic analysis (ß = -0.011; P = 0.48). In addition, acti-CT90 was significantly associated with mean RNFL thickness both in the elderly (⩾60 yr; ß = -0.058; P = 0.002) and nonelderly (<60 yr; ß = -0.054; P = 0.007).Conclusions: Acti-CT90, but not acti-ODI3%, was associated with mean RNFL thinning in participants irrespective of age in the elderly or nonelderly. Further prospective studies are required to investigate whether the prevention of hypoxic burden, which was shown as acti-CT90 in this study, is favorable for RNFL thinning.

Paraneoplastic Cerebellar Degeneration Accompanied by Seropositivity for Anti-GAD65, Anti-SOX-1 and Anti-VGCC Antibodies Due to Small-cell Lung Cancer.

Paraneoplastic cerebellar degeneration (PCD) is a paraneoplastic neurological syndrome that is rarely accompanied by seropositivity with a combination of multiple antibodies. We herein report a 50-year-old man with PCD accompanied by small-cell lung cancer (SCLC). This patient was seropositive for anti-glutamic acid decarboxylase 65, anti-SRY-related HMG-box gene 1 and anti-voltage-gated calcium channel antibodies. After chemoradiation therapy without immunotherapy, cerebellar ataxia of the trunk and limbs markedly improved, along with a notable amelioration of SCLC. This case suggests that tumor therapy should be started immediately and that a panel of anti-neuronal antibodies should be evaluated when PCD with SCLC is suspected.

Associations between Sleep-Disordered Breathing and Serum Uric Acid and Their Sex Differences: The Nagahama Study.

Sleep-disordered breathing (SDB) is often accompanied by noncommunicable diseases (NCDs), including gout. However, the association between serum uric acid (sUA) levels and NCDs is complicated in patients with SDB. We aimed to clarify this issue utilizing large-scale epidemiological data. This community-based study included 9850 inhabitants. SDB and its severity were assessed by a 3% oxygen desaturation index (3% ODI) corrected for sleep duration using wrist actigraphy. The associations between sUA and moderate to severe SDB (MS-SDB) and sUA and NCDs in patients with MS-SDB were analyzed. A total of 7895 subjects were eligible. In females, the prevalence of MS-SDB increased according to an elevation in sUA levels even after adjusting for confounders, and sUA ≥ 5 mg/dL was the threshold. These were not found in males. There was a positive interaction between sUA ≥ 5 mg/dL and female sex for MS-SDB. In females with MS-SDB, the prevalence of diabetes mellitus (DM) increased according to an elevation in sUA levels, and those with sUA ≥ 5 mg/dL showed a higher prevalence of DM than their counterparts. There is a clear correlation between sUA levels and the severity of SDB, and elevated sUA poses a risk for DM in females with MS-SDB.

Rapid weight change as a predictor of disability among community-dwelling Japanese older adults.

AIM: To fill the knowledge gap regarding weight change and the onset of disability in community-dwelling Japanese older adults, we investigated the potential effects of rapid weight change on disability risk as defined by Japan's long-term care insurance (LTCI) system. METHODS: We analyzed data from a longitudinal study of 10 375 community-dwelling older Japanese adults (≥65 years) who were not LTCI needs certified at baseline and joined the study from 2002 to 2005. Weight change (percentage) was calculated by subtracting participants' weight in the previous year from that measured during a physical examination at study commencement. The five weight-change categories ranged from sizable weight loss (≤ -8.0%) to sizable weight gain (≥ +8.0%). Disability was defined according to LTCI certifications at follow-up. Hazard ratios (HRs) and 95% confidence intervals were calculated for new-onset disability using a Cox proportional hazards model that fitted the proportional subdistribution hazards regression model with weights for competing risks of death. RESULTS: During the mean 10.5-year follow-up, 2994 participants developed a disability. Sizable weight loss (HR [95% confidence intervals], 1.41 [1.17-1.71]) and weight loss (1.20 [1.05-1.36]) were significant predictors of disability onset. Sizable weight gain (1.45 [1.07-1.97]) corresponded to severe disability. Stratified analyses by lifestyle and initial body mass index categories revealed more pronounced associations between weight change and disability risk in the unhealthy lifestyle and below initial normal body mass index groups. CONCLUSIONS: Rapid and sizable weight gain could be additional criteria for disability risk in older adults. Geriatr Gerontol Int 2023; 23: 809-816.

Neuroarchitecture of the central complex in the Madeira cockroach Rhyparobia maderae: Pontine and columnar neuronal cell types.

Insects have evolved remarkable abilities to navigate over short distances and during long-range seasonal migrations. The central complex (CX) is a navigation center in the insect brain that controls spatial orientation and directed locomotion. It is composed of the protocerebral bridge (PB), the upper (CBU) and lower (CBL) division of the central body, and a pair of noduli. While most of its functional organization and involvement in head-direction coding has been obtained from work on flies, bees, and locusts that largely rely on vision for navigation, little contribution has been provided by work on nocturnal species. To close this gap, we have investigated the columnar organization of the CX in the cockroach Rhyparobia maderae. Rhyparobia maderae is a highly agile nocturnal insect that relies largely but not exclusively on antennal information for navigation. A particular feature of the cockroach CX is an organization of the CBU and CBL into interleaved series of eight and nine columns. Single-cell tracer injections combined with imaging and 3D analysis revealed five systems of pontine neurons connecting columns along the vertical and horizontal axis and 18 systems of columnar neurons with topographically organized projection patterns. Among these are six types of neurons with no correspondence in other species. Many neurons send processes into the anterior lip, a brain area highly reduced in bees and unknown in flies. While sharing many features with the CX in other species, the cockroach CX shows some unique attributes that may be related to the ecological niche of this insect.

Hyperfructosemia in sleep disordered breathing: metabolome analysis of Nagahama study.

Sleep disordered breathing (SDB), mainly obstructive sleep apnea (OSA), constitutes a major health problem due to the large number of patients. Intermittent hypoxia caused by SDB induces alterations in metabolic function. Nevertheless, metabolites characteristic for SDB are largely unknown. In this study, we performed gas chromatography-mass spectrometry-based targeted metabolome analysis using data from The Nagahama Study (n = 6373). SDB-related metabolites were defined based on their variable importance score in orthogonal partial least squares discriminant analysis and fold changes in normalized peak-intensity levels between moderate-severe SDB patients and participants without SDB. We identified 20 metabolites as SDB-related, and interestingly, these metabolites were frequently included in pathways related to fructose. Multivariate analysis revealed that moderate-severe SDB was a significant factor for increased plasma fructose levels (ß = 0.210, P = 0.006, generalized linear model) even after the adjustment of confounding factors. We further investigated changes in plasma fructose levels after continuous positive airway pressure (CPAP) treatment using samples from patients with OSA (n = 60) diagnosed by polysomnography at Kyoto University Hospital, and found that patients with marked hypoxemia exhibited prominent hyperfructosemia and their plasma fructose levels lowered after CPAP treatment. These data suggest that hyperfructosemia is the abnormality characteristic to SDB, which can be reduced by CPAP treatment.

Residual excessive daytime sleepiness in patients with sleep apnea syndrome receiving continuous positive airway pressure in Japan: A single-center study.

Excessive daytime sleepiness (EDS) is a symptom of sleep apnea syndrome (SAS). In some patients with SAS who undergo continuous positive airway pressure (CPAP) therapy, EDS persists (residual EDS). However, knowledge of residual EDS in Japan is limited. Therefore, we examined EDS as defined by the Japanese version of the Epworth Sleepiness Scale (a score of ≥11) before and after long-term (≥1 year) CPAP therapy in 490 patients with SAS. Good adherence to CPAP therapy was defined as its use for at least 4 h during 70% of the nights. The prevalence of residual EDS was 9.4%. Residual EDS was negatively associated with good adherence to CPAP therapy. Furthermore, the longer the CPAP therapy duration after initiation, the lower the prevalence of residual EDS. Therefore, the findings on the prevalence of residual EDS and its association with CPAP therapy in Japan are probably similar to those of other countries.

A Case with Anti-ganglioside Antibodies Showing Multiple Cranial Nerve Palsies Detected on Gadolinium-enhanced Magnetic Resonance Imaging.

The anti-GQ1b IgG antibody is often accompanied by other anti-ganglioside antibodies, which induces various neurological symptoms. We herein report a patient with anti-ganglioside antibodies, including anti-GQ1b IgG and anti-GT1a IgG antibodies, showing bilateral ophthalmoplegia, facial nerve palsies, dysarthria, dysphagia, dysesthesia in both hands, and enhancement of the bilateral oculomotor, abducens, and facial nerves on gadolinium (Gd)-enhanced T1-weighted brain magnetic resonance imaging (MRI). He was first treated with intravenous immunoglobulin, which improved ophthalmoplegia, bulbar palsies, and dysesthesia of hands, but the facial nerve palsies worsened, and Gd enhancement of the brain nerves persisted. High-dose methylprednisolone therapy subsequently improved the facial nerve palsies and Gd enhancement of the cranial nerves. This is the first case with anti-ganglioside antibodies presenting with multiple cranial nerve palsies that was followed to track the changes in the Gd enhancement of cranial nerves on MRI.

Effects of using in-line bacterial filters with continuous positive airway pressure devices in patients with sleep disordered breathing.

In June 2021, Philips Respironics first advised the use of in-line bacterial filters in response to a recall of continuous positive airway pressure (CPAP) devices. However, the effects of using in-line filters with CPAP devices have not yet been examined in a clinical setting. Here, we retrospectively evaluated 160 patients with sleep-disordered breathing (SDB) who voluntarily used in-line bacterial filters. Patients' perceptions of CPAP pressure after using in-line filters were investigated via a verbal interview. Patients described CPAP pressure as very weak (13, 8.1%), somewhat weak (42, 26.2%), unchanged (103, 64.4%), or somewhat strong (2, 1.3%). Five of the thirteen patients (38.5%) who described CPAP pressure as very weak discontinued the use of in-line filters. The apnea-hypopnea index obtained from the CPAP devices did not change after using in-line filters (n = 129, p = 0.85). Hence, although in-line bacterial filters could change patients' perceptions of CPAP pressure, they did not influence SDB control.

The sky compass network in the brain of the desert locust.

Many arthropods and vertebrates use celestial signals such as the position of the sun during the day or stars at night as compass cues for spatial orientation. The neural network underlying sky compass coding in the brain has been studied in great detail in the desert locust Schistocerca gregaria. These insects perform long-range migrations in Northern Africa and the Middle East following seasonal changes in rainfall. Highly specialized photoreceptors in a dorsal rim area of their compound eyes are sensitive to the polarization of the sky, generated by scattered sunlight. These signals are combined with direct information on the sun position in the optic lobe and anterior optic tubercle and converge from both eyes in a midline crossing brain structure, the central complex. Here, head direction coding is achieved by a compass-like arrangement of columns signaling solar azimuth through a 360° range of space by combining direct brightness cues from the sun with polarization cues matching the polarization pattern of the sky. Other directional cues derived from wind direction and internal self-rotation input are likely integrated. Signals are transmitted as coherent steering commands to descending neurons for directional control of locomotion and flight.

Sleep disordered breathing and haemoglobin A1c levels within or over normal range and ageing or sex differences: the Nagahama study.

Recently an association between blood glucose dysregulation and sleep disruption was suggested. The association between sleep disordered breathing, most of which is due to obstructive sleep apnea (OSA) in the general population, and diabetic severity, as well as the impact of antidiabetic treatment, remains unclear. This study aimed to investigate these associations as well as age and sex differences. This cross-sectional study evaluated 7,680 community participants as the main cohort (population-based cohort). OSA was assessed by the 3% oxygen desaturation index from pulse oximetry, which was corrected for sleep duration obtained by wrist actigraphy. For arguing the limitations for using pulse oximetry, 597 hospitalised patients, who were assessed by the apnea-hypopnea index from attended polysomnography, were also evaluated as the validation cohort (hospital-based cohort). Moderate-to-severe OSA was more prevalent as haemoglobin A1c (HbA1c) levels increased (<5.6%/5.6%-<6.5%/6.5%-<7.5%/≥7.5%, respectively) in both cohorts (p < 0.001), but only in those without antidiabetic treatment. The HbA1c level was an independent factor for moderate-to-severe OSA (population-based cohort, odds ratio [OR] 1.26, 95% confidence interval [CI] 1.10-1.45; hospital-based cohort, OR 1.69, 95% CI 1.22-2.33, per 1% increase). These associations were more prominent in the middle-aged (aged <60 years) than in the elderly (aged ≥60 years) and in women than in men in both cohorts. The prevalence of moderate-to-severe OSA in patients with antidiabetic treatment in the hospital-based cohort was ≥75% regardless of HbA1c levels. In conclusion, an association between the prevalence of OSA and HbA1c level even within or over the normal range was found only in patients without antidiabetic treatment and was more prominent in the middle-aged and in women.

Occupational disparities in COVID-19 vaccine hesitancy in Japan.

Background: We examined occupational disparities in COVID-19 vaccine hesitancy in Japan. Methods: Cross-sectional online surveys were conducted among of residents living in Iwate Prefecture from July 2 to 4 and from October 1 to 3 in 2021 (total n=17,914). Intention to get vaccinated for COVID-19 was assessed by self-report questions. We calculated odds ratios for vaccine hesitancy among occupational groups using logistic regression models controlling for covariates and stratified by age and sex groups. Results: The overall prevalence of vaccine hesitancy was 5.5% in our sample of working-age adults. Women <40 years were also 1.6 times more likely to be vaccine hesitant, citing concerns about adverse effects on pregnancy or breastfeeding. Among people aged 40-59 years, workers in the service industry, manufacturing industry, and the unemployed were significantly more likely to have perceived vaccine hesitancy regardless of sex. Young service workers viewed themselves as being more vulnerable to risk of infection but less susceptible to getting severe disease, whilst exhibiting low levels of vaccine knowledge. Middle-aged (40-59 years) workers in the manufacturing industry underestimated both vulnerability to infection and disease severity, as well as demonstrated low knowledge of vaccines and practice of preventive measures. Conclusions: While complex and heterogeneous reasons for COVID-19 vaccine hesitancy have been cited in Western countries (e.g., mistrust of government, medical mistrust, and conspiracy beliefs), the situation in Japan may be more amenable to educational interventions targeting specific occupations. Policymakers should target interventions for increasing vaccine readiness in high risk occupations.

A high level of vaccine knowledge increases people's behavioral risks for contracting COVID-19 in Japan.

BACKGROUND: There has been no study in which the association between levels of vaccine knowledge and preventive behaviors was examined during the COVID-19 pandemic. We examined the transition to risky (transmission) behavior according to level of vaccine knowledge over a seven-month period when vaccines became widely available in Japan. METHODS: A series of cross-sectional surveys were conducted using rapid online surveys of residents in Iwate Prefecture from December 4 to 7 in 2020 (the first survey) and from July 2 to 4 in 2021 (the fourth survey). We calculated each individual's risk of acquiring SARS-CoV-2 infection using a quantitative assessment tool (the microCOVID calculator). The respondents' level of knowledge regarding the COVID-19 vaccine was assessed by a questionnaire and was divided into four groups: very low level, low level, moderate level, and high level of vaccine knowledge. RESULTS: People with a high-level knowledge about the vaccine had significantly higher odds ratios (ORs) of transitioning to high-risk behavior compared to people with a low level of vaccine knowledge (OR [95% confidence interval (CI)], 1.50 [1.17-1.93]; P = 0.001). There was a dose-response association according to the four levels of vaccine knowledge, while engagement in preventive measures in the first survey was not associated with high-risk behavior in the follow-up survey. CONCLUSIONS: Since new variants of SARS-CoV-2 have evolved, policy makers should continue to communicate strong messages to keep a high level of consciousness and maintain basic preventive measures even after widespread vaccination.

Multimodal Telemonitoring for Weight Reduction in Patients With Sleep Apnea: A Randomized Controlled Trial.

BACKGROUND: Telemonitoring the use of CPAP devices and remote feedback on device data effectively optimizes CPAP adherence in patients with OSA. RESEARCH QUESTION: Can expanding the scope of telemonitoring and remote feedback to body weight (BW), BP, and physical activity enhance efforts for BW reduction in Patients with OSA receiving CPAP? STUDY DESIGN AND METHODS: Participants were recruited from patients at 16 sleep centers in Japan with OSA and obesity who were receiving CPAP therapy. Obesity was defined as a BMI of ≥ 25 kg/m2, based on Japanese obesity guidelines. Implementation of CPAP telemonitoring was enhanced with electronic scales, BP monitors, and pedometers that could transmit data from devices wirelessly. Participants were randomized to the multimodal telemonitoring group or the usual CPAP telemonitoring group and were followed up for 6 months. Attending physicians provided monthly telephone feedback calls to the usual CPAP telemonitoring group on CPAP data obtained remotely. In the multimodal telemonitoring group, physicians additionally encouraged participants to reduce their BW, after sharing the remotely obtained data on BW, BP, and step count. The primary outcome was set as ≥ 3% BW reduction from baseline. RESULTS: One hundred sixty-eight participants (BMI, 31.7 ± 4.9 kg/m2) completed the study, and ≥ 3% BW reduction occurred in 33 of 84 participants (39.3%) and 21 of 84 participants (25.0%) in the multimodal telemonitoring and usual CPAP telemonitoring groups, respectively (P = .047). Whereas no significant differences were found between the two groups in the change in office and home BP, daily step counts during the study period were significantly higher in the multimodal telemonitoring group than in the usual CPAP telemonitoring group (4,767 steps/d [interquartile range (IQR), 2,864-6,617 steps/d] vs 3,592 steps/d [IQR, 2,117-5,383 steps/d]; P = .02) INTERPRETATION: Multimodal telemonitoring may enhance BW reduction efforts in patients with OSA and obesity. TRIAL REGISTRY: UMIN Clinical Trials Registry; No.: UMIN000033607; URL: www.umin.ac.jp/ctr/index.htm.

Simultaneous Discrimination of Cereulide-Producing Bacillus cereus and Psychrotolerant B. cereus Group by Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry.

ABSTRACT: Cereulide-producing Bacillus cereus, which causes foodborne illnesses with vomiting, and psychrotolerant B. cereus group strains such as Bacillus mycoides, which can grow at ≥7°C and cause spoilage of refrigerated foods, are significant concerns for the food industry. Rapid and simple methods to discriminate the cereulide-producing B. cereus and psychrotolerant B. cereus group strains from other B. cereus group strains are needed. We developed a novel, rapid, and simple method with matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analysis for simultaneous discrimination of these two groups from other B. cereus group strains. A potassium adduct of cereulide was used to detect cereulide-producing B. cereus, and three ribosomal subunit proteins (L30, S16, and S20) were used to detect psychrotolerant B. cereus group. A total of 51 B. cereus group strains were analyzed by MALDI-TOF MS. The biomarkers allowed successful discrimination of 16 cereulide-producing B. cereus and 15 psychrotolerant B. cereus group strains from other B. cereus group strains. The results showed that this MALDI-TOF MS analysis allows simultaneous discrimination of cereulide-producing B. cereus and psychrotolerant B. cereus group strains from other B. cereus group strains. This efficient method has the potential to be a valuable tool for ensuring food safety.