Necrotizing Fasciitis Due to Group A Streptococcus: A Case of a Deteriorating Biphasic-like Clinical Course Over Five Days with a Devastating Outcome.

Necrotizing fasciitis (NF) is a life-threatening disease with high mortality and rapidly progressive clinical manifestations1. Early detection and surgical management coupled with antibiotic treatment are crucial for the survival, and the patient survival is heavily dependent on clinical decisions2,3. However, it is not widely known that NF does not always follow a typical clinical course, and there have been no case reports of NF following an atypical clinical course. Although the course of the disease depends on the individual patient, it remains a challenge for physicians to determine the precise timing when patients are most likely to survive multiple surgical interventions. We encountered a challenging case presenting with an atypical clinical course. We herein report a 31-year-old man who followed a deteriorating biphasic-like clinical course and presented with extensive NF and streptococcal toxic shock syndrome due to Group A Streptococcus. This case serves to inform physicians of the existence of NF with an atypical and deteriorating biphasic-like clinical course, emphasizing the need for a careful evaluation of the patient condition.

Subacute Thyroiditis Following COVID-19: A Case of Diagnostic Challenge in the Absence of Neck Pain.

This case report presents a 77-year-old woman who developed subacute thyroiditis following COVID-19. The patient exhibited atypical symptoms, including fever, fatigue, anorexia, significant weight loss, headaches, and palpitations, without the typical neck pain or tenderness associated with thyroiditis. One week later, a follow-up examination showed mild enlargement and tenderness of the thyroid. Laboratory tests indicated elevated thyroid hormone levels and suppressed thyroid-stimulating hormone. Ultrasonography revealed diffuse thyroid enlargement with poor blood flow, consistent with subacute thyroiditis. Despite the absence of typical neck pain, the diagnosis was supported by clinical, laboratory, and imaging findings. This case suggests the importance of considering subacute thyroiditis as a potential secondary condition following COVID-19, even in the absence of typical symptoms. Clinicians should consider that and perform thorough evaluations in patients with recent COVID-19 exposure and nonspecific symptoms.

Clostridium ramosum bacteremia: A case series at a general acute care hospital.

Clostridium ramosum infections have been rarely reported, probably due to underestimating in clinical practice. Seven patients with bacteremia from gastrointestinal sources and skin and soft tissue were recognized between 2009 and 2020. Most of them were older and in compromised status, and they had risk factors including cancer, diabetes, liver cirrhosis, gangrene, and pressure ulcers. The source of infections was considered bacterial translocation from the gastrointestine and the skin and soft tissue infections. All patients were treated with antimicrobials, and two received surgical interventions. Four patients died secondary to sepsis due to C. ramosum. The bacteremia of C. ramosum should be appropriately evaluated and treated, especially in compromised hosts.

Evaluation of a novel urinary antigen test kit for diagnosing Legionella pneumonia.

OBJECTIVES: The aim of this study was to evaluate the diagnostic utility of a novel test kit that could theoretically detect all serogroups of Legionella pneumophila for diagnosing Legionella pneumonia, in comparison with existing kits. METHODS: This study was conducted in 16 hospitals in Japan from April 2016 to December 2018. Three urinary antigen test kits were used: the novel kit (LAC-116), BinaxNOW Legionella (Binax), and Q-line Kyokutou Legionella (Q-line). In addition, sputum culture and nucleic acid detection tests and serum antibody tests were performed where possible. The diagnostic accuracy and correlations of the novel kit with the two existing kits were analyzed. RESULTS: In total, 56 patients were diagnosed with Legionella pneumonia. The sensitivities of LAC-116, Binax, and Q-line were 79%, 84%, and 71%, respectively. The overall match rate between LAC-116 and Binax was 96.8% and between LAC-116 and Q-line was 96.4%. One patient had L. pneumophila serogroup 2, and only LAC-116 showed a positive result, whereas Binax and Q-line did not. CONCLUSIONS: The novel Legionella urinary antigen test kit was useful for diagnosing Legionella pneumonia. In addition, it could detect Legionella pneumonia caused by non-L. pneumophila serogroup 1.

Community-acquired liver abscess caused by capsular genotype K2-ST375 hypervirulent Klebsiella pneumoniae isolates.

Hypervirulent Klebsiella pneumoniae has been associated with community-acquired liver abscesses in relatively healthy subjects since the 1990s, occasionally accompanied by disseminated disease. While isolates of capsular genotype K1 belonging to sequence type (ST) 23 have been the most prominent causative pathogen of this syndrome, other virulent clones have been implicated sporadically in recent years. A 68-year-old woman with diabetes in Okinawa, Japan suffered from a K. pneumoniae liver abscess, which recurred after a prolonged antibacterial treatment. The clinical course was further complicated with multiple sites of dissemination. Another 45-year-old woman living in Okinawa without underlying conditions was also diagnosed with a community-acquired K. pneumoniae liver abscess, which was cured with antibacterial treatment alone. Both of the causative isolates carried rmpA and aerobactin genes, and were confirmed as capsular genotype K2 and ST375. K. pneumoniae K2-ST375 is a hypervirulent clone of epidemiological significance causing severe community-acquired infections in relatively healthy subjects. More information about clinical characteristics and molecular epidemiology of hypervirulent K. pneumoniae clones other than K1-ST23 should be accumulated.

A hemin auxotrophic Enterobacter cloacae clinical isolate with increased resistance to carbapenems and aminoglycosides.

Small-colony variants (SCVs) were obtained from an Enterobacter cloacae clinical isolate in Okinawa, Japan. One variant showed auxotrophy for hemin with a deletion of 20 365 nucleotides, dosC-ydiK-mmuP-mmuM-tauA-tauB-tauC-tauD-hemB-yaiT-yaiV-ampH-yddQ-sbmA-yaiW-yaiY-yaiZ, including hemB, and was more resistant to aminoglycosides and carbapenems, but more susceptible to aztreonam, than the parent strain.

Hypercalcaemia caused by active pulmonary tuberculosis in an elderly person without fever or pulmonary symptoms.

Many diseases can cause hypercalcaemia, including primary hyperparathyroidism, cancer, drugs and granulomatous diseases. A nursing home resident aged 81 years was admitted because of altered mental status. The patient did not have fever, cough, sputum or night sweat. Hypercalcaemia was identified as a cause of the consciousness disturbance. Chest radiograph showed no acute process. Laboratory workups revealed elevated serum levels of 1,25-(OH)2 vitamin D3 and positive T-spot test. Microscopic examination of the suctioned sputum identified acid-fast bacilli, which was confirmed as Mycobactrium tuberculsosis Tuberculosis should be considered as the important cause of hypercalcaemia since early diagnosis and treatment is recommended for preventing its outbreak among people with close contacts with patients.

Replica analysis for the duality of the portfolio optimization problem.

In the present paper, the primal-dual problem consisting of the investment risk minimization problem and the expected return maximization problem in the mean-variance model is discussed using replica analysis. As a natural extension of the investment risk minimization problem under only a budget constraint that we analyzed in a previous study, we herein consider a primal-dual problem in which the investment risk minimization problem with budget and expected return constraints is regarded as the primal problem, and the expected return maximization problem with budget and investment risk constraints is regarded as the dual problem. With respect to these optimal problems, we analyze a quenched disordered system involving both of these optimization problems using the approach developed in statistical mechanical informatics and confirm that both optimal portfolios can possess the primal-dual structure. Finally, the results of numerical simulations are shown to validate the effectiveness of the proposed method.

Portfolio optimization problem with nonidentical variances of asset returns using statistical mechanical informatics.

The portfolio optimization problem in which the variances of the return rates of assets are not identical is analyzed in this paper using the methodology of statistical mechanical informatics, specifically, replica analysis. We defined two characteristic quantities of an optimal portfolio, namely, minimal investment risk and investment concentration, in order to solve the portfolio optimization problem and analytically determined their asymptotical behaviors using replica analysis. Numerical experiments were also performed, and a comparison between the results of our simulation and those obtained via replica analysis validated our proposed method.

[Three Cases of Tsutsugamushi Disease in Miyakojima Island, Okinawa, Japan].

Tsutsugamushi disease (Scrub thyphus) has been reported from all over Japan except the Hokkaido area. In Okinawa, only one patient was reported in 2001, who was infected outside Okinawa Prefecture. The first case infected in Okinawa was reported at Miyakojima Island in 2008. We report herein on the second case diagnosed in 2010, and the third and fourth in 2011, and all three patients were suspected to have been infected at Ikemajima Island adjacent to the island of Miyakojima. The patients recovered without any severe complications after antibiotic therapy with tetracyclines. We should take Tsutsugamushi disease into consideration in the differential diagnosis for a patient with fever, skin rash, and/or eschar even in the Okinawa area. Implementation of appropriate information and education about the disease should be carried out for local residents and tourists.

Falciparum Malaria Incidentally Pretreated with Azithromycin.

A 65-year-old man, who recently returned from Liberia, visited a clinic complaining of fever, and azithromycin was prescribed. The patient presented to a general hospital 5 days after the onset of symptoms, however, a blood smear examination failed to detect malaria. Contrary to the blood smear result, a rapid antigen test in our hospital was strongly-positive for falciparum malaria, indicating a high level of malarial antigen in the blood. Moreover, laboratory examinations on admission showed a tendency for improvement. We assumed that the administration of azithromycin partially treated malaria, thus complicating the blood smear diagnosis. We should be careful in prescribing azithromycin, which is widely used in clinics, to travelers returning from malaria-endemic countries.

Belief Propagation Algorithm for Portfolio Optimization Problems.

The typical behavior of optimal solutions to portfolio optimization problems with absolute deviation and expected shortfall models using replica analysis was pioneeringly estimated by S. Ciliberti et al. [Eur. Phys. B. 57, 175 (2007)]; however, they have not yet developed an approximate derivation method for finding the optimal portfolio with respect to a given return set. In this study, an approximation algorithm based on belief propagation for the portfolio optimization problem is presented using the Bethe free energy formalism, and the consistency of the numerical experimental results of the proposed algorithm with those of replica analysis is confirmed. Furthermore, the conjecture of H. Konno and H. Yamazaki, that the optimal solutions with the absolute deviation model and with the mean-variance model have the same typical behavior, is verified using replica analysis and the belief propagation algorithm.

Self-Averaging Property of Minimal Investment Risk of Mean-Variance Model.

In portfolio optimization problems, the minimum expected investment risk is not always smaller than the expected minimal investment risk. That is, using a well-known approach from operations research, it is possible to derive a strategy that minimizes the expected investment risk, but this strategy does not always result in the best rate of return on assets. Prior to making investment decisions, it is important to an investor to know the potential minimal investment risk (or the expected minimal investment risk) and to determine the strategy that will maximize the return on assets. We use the self-averaging property to analyze the potential minimal investment risk and the concentrated investment level for the strategy that gives the best rate of return. We compare the results from our method with the results obtained by the operations research approach and with those obtained by a numerical simulation using the optimal portfolio. The results of our method and the numerical simulation are in agreement, but they differ from that of the operations research approach.

Toward the rational use of standardized infection ratios to benchmark surgical site infections.

BACKGROUND: The National Healthcare Safety Network transitioned from surgical site infection (SSI) rates to the standardized infection ratio (SIR) calculated by statistical models that included perioperative factors (surgical approach and surgery duration). Rationally, however, only patient-related variables should be included in the SIR model. METHODS: Logistic regression was performed to predict expected SSI rate in 2 models that included or excluded perioperative factors. Observed and expected SSI rates were used to calculate the SIR for each participating hospital. The difference of SIR in each model was then evaluated. RESULTS: Surveillance data were collected from a total of 1,530 colon surgery patients and 185 SSIs. C-index in the model with perioperative factors was statistically greater than that in the model including patient-related factors only (0.701 vs 0.621, respectively, P < .001). At one particular hospital, for which the percentage of open surgery was lowest (33.2%), SIR estimates changed considerably from 0.92 (95% confidence interval: 0.84-1.00) for the model with perioperative variables to 0.79 (0.75-0.85) for the model without perioperative variables. In another hospital with a high percentage of open surgery (88.6%), the estimate of SIR was decreased by 12.1% in the model without perioperative variables. CONCLUSION: Because surgical approach and duration of surgery each serve as a partial proxy of the operative process or the competence of surgical teams, these factors should not be considered predictive variables.

[Comparison of pneumonia severity indices between modified A-DROP system and current A-DROP system predicting outcomes for patients hospitalized with community-acquired pneumonia].

BACKGROUND: The A-DROP is a predicting pneumonia severity index which is adopted in the Japanese Respiratory Society (JRS) guidelines. For community-acquired pneumonia, we made a modified A-DROP, adding two new index items to the current A-DROP. Then, we retrospectively compared the modified A-DROP with the current A-DROP regarding 30-day mortality. METHODS AND RESULTS: We analyzed consecutive 227 patients hospitalized with community-acquired pneumonia (mean age 79.0 years). The added index items were respiratory rate > or = 30/min and the presence or absence of underlying diseases. There were 16 fatalities (7.0%). In the extremely severe group, the sensitivities of the 30-day death and odds ratios were 19.9% and 9.5 in the current A-DROP, but 75.0% and 14.1 for the modified A-DROP, respectively. In addition, regarding the receiver-operating characteristic (ROC) area under the curve for the 30-day death ratio, the current A-DROP and modified A-DROP were 0.807 and 0.840, respectively. CONCLUSIONS: The modified A-DROP improved the ability to predict outcomes compared with the current A-DROP.

Computed tomographic features of 23 sporadic cases with Legionella pneumophila pneumonia.

OBJECTIVE: To describe the chest computed tomographic (CT) findings of Legionella pneumophila pneumonia. METHODS: CT scans obtained from 23 sporadic cases of L. pneumophila pneumonia were retrospectively reviewed. Chest CT findings were analyzed with regard to the patterns and distributions of pulmonary abnormalities. We also analyzed the histopathology of lungs from guinea pigs with experimentally induced L. pneumophila pneumonia. RESULTS: Consolidation and ground-glass opacity (GGO) were the main findings of CT scans in L. pneumophila pneumonia. The distribution of opacities was categorized as non-segmental (n=20) and segmental (n=4). Non-segmental distribution may follow an onset of segmental distribution. Pleural effusion was observed in 14 (58.3%) patients, of which 13 were accompanied with non-segmental distribution. Abscess formation was observed in only one immunocompromised patient. In the animal pneumonia model, the lesions comprised of terminal bronchioles, alveolar spaces, and interstitia. Small bacilli were observed to be contained by many macrophages within the alveoli. CONCLUSION: Non-segmental distribution was significantly more frequent than segmental distribution in L. pneumophila pneumonia. It is possible that L. pneumophila infection initially results in segmental pneumonia, which progresses to typical non-segmental distribution.

[Effects and management of odontogenic infections on pulmonary infections].

Carious and periodontal disease is strongly associated with pulmonary infections. Aspiration pneumonia often develops lung abscess and/or empyema, and sometimes leads to death in elderly patients. It is often repeatedly seen in most of elderly patients, which leads to general weakness, prolonged bed rest, and several complications. There are two pathophysiological factors for aspiration pneumonia. One is due to odontogenic infections: aspirated oral microorganisms reach pulmonary alveoli, grow, and develop their pathogenicity. The other is host factors: alcoholism, diabetes, or bedridden status reduces cough reflex, airway clearance, and functions of phagocytes. The prevention of aspiration pneumonia is significant from medical, social, and economical viewpoints, although the main management of pneumonia is antimicrobial chemotherapy. "Oral care" has recently been of interest as a control means for odontogenic infections and aspiration pneumonia. A dental hygienist and speech therapists in our hospital have implemented active intervention in oral care of patients with risk of aspiration pneumonia, which has made considerable achievements.

Elsberg syndrome with eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis.

A 42-year-old man was admitted to our hospital with a history of fever, headache and disorientation. His cerebrospinal fluid revealed eosinophilia and his serum had an antibody against Angiostrongylus cantonensis (A. cantonensis). Then, he was diagnosed as eosinophilic meningoencephalitis caused by A. cantonensis. He was treated with repeated lumbar punctures and oral prednisolone. Although a symptom he had been suffering from at the time of his admission was urinary retention, this symptom disappeared as his general condition improved. Therefore his case was considered to be Elsberg syndrome with eosinophilic meningoencephalitis caused by A. cantonensis.

In vitro activity of sitafloxacin against clinical strains of Streptococcus pneumoniae with defined amino acid substitutions in QRDRs of gyrase A and topoisomerase IV.

OBJECTIVES: Fluoroquinolone-resistant Streptococcus pneumoniae are increasing worldwide rapidly. In vitro activities of sitafloxacin were evaluated against clinical isolates of S. pneumoniae resistant to levofloxacin (MIC of levofloxacin > or = 4 mg/L), which were characterized genetically. METHODS: The quinolone resistance determining regions (QRDRs) of gyrA, gyrB, parC and parE of these strains were analysed by PCR-based sequencing. MICs of sitafloxacin and other quinolones were determined by a microdilution broth method. RESULTS: All 18 strains had at least one amino acid substitution in the QRDRs of GyrA and ParC, which included Ser-81-->Tyr/Phe and Glu-85-->Lys in GyrA and Ser-79-->Phe/Ile/Tyr, Asp-83-->Tyr, Asn-91-->Asp, Ser-107-->Phe, Lys-137-->Asn and Ala-142-->Ser in ParC. Most isolates had Asp-435-->Asn/Ile-460-->Val/Ala-596-->Thr substitutions in ParE, while no amino acid substitution in GyrB was noted in all isolates. Ten isolates for which levofloxacin MICs were 16 or 32 mg/L had multiple mutations in both GyrA and ParC. The MIC80 value of sitafloxacin for levofloxacin-resistant isolates was 0.25 mg/L. The range of MICs of sitafloxacin for isolates resistant to levofloxacin (MIC 4-32 mg/L) was 0.016-0.5 mg/L. CONCLUSIONS: These findings warrant further studies to evaluate the usefulness of sitafloxacin in the treatment of levofloxacin-resistant S. pneumoniae infection.