Pseudomonas otitidis bacteremia in an immunocompromised patient with cellulitis: case report and literature review.

BACKGROUND: Pseudomonas otitidis belongs to the genus Pseudomonas and causes various infections, including ear, skin, and soft tissue infections. P. otitidis has a unique susceptibility profile, being susceptible to penicillins and cephalosporins but resistant to carbapenems, due to the production of the metallo-ß-lactamase called POM-1. This revealed genetic similarities with Pseudomonas aeruginosa, which can sometimes lead to misidentification. CASE PRESENTATION: We report the case of a 70-year-old Japanese male who developed cellulitis and bacteremia during chemotherapy for multiple myeloma. He was initially treated with meropenem, but blood culture later revealed gram-negative bacilli identified as P. otitidis using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Carbapenem resistance was predicted from previous reports; therefore, we switched to dual therapy with levofloxacin and cefepime, and favorable treatment results were obtained. CONCLUSION: This is the first reported case of P. otitidis cellulitis and bacteremia in an immunocompromised patient. Carbapenems are typically used in immunocompromised patients and P. otitidis is often resistant to it. However, its biochemical properties are similar to those of Pseudomonas aeruginosa; therefore, its accurate identification is critical. In the present study, we rapidly identified P. otitidis using MALDI-TOF MS and switched from carbapenems to an appropriate antimicrobial therapy, resulting in a successful outcome.

Sex difference in clinical presentation of patients with infectious mononucleosis caused by Epstein-Barr virus.

INTRODUCTION: There are few studies on sex difference in patients with infectious mononucleosis caused by Epstein-Barr virus (EBV-IM). We performed a retrospective study to evaluate the sex difference in clinical presentation of patients with EBV-IM. METHODS: We performed a single-center retrospective study evaluating >14-year-old patients with serologically confirmed EBV-IM during 2006-2017. We compared the patients' age, symptoms, physical findings, and laboratory data between male and female patients. To adjust for confounding factors, we performed a logistic regression analysis based on the results of univariate comparisons. RESULT: Of the 122 eligible patients (56 male and 66 female, ratio: 1:1.2), the median ages were 26 years old (interquartile range [IR], 22-31.5 years old]) and 22 years old (IR, 20-25 years old) for males and females, respectively (p < 0.001). Headache was significantly more prevalent in males (25.0% vs. 10.6%, p = 0.036). Leukocyte count was also significantly higher in males (11,400/mm3 [IR, 7,600-14,100/mm3] vs. 9,400/mm3 [IR, 6,600-11,600/mm3], p = 0.021). The prevalence of periorbital edema (male: 3.6% vs. female: 18.1%, p = 0.012) and severity of transaminase elevation were significantly higher in females. The regression analysis evaluating clinical characteristics of male patients showed that age >30 years old, headache, and leukocyte >11,000/mm3 had high odds ratios. CONCLUSION: Our single-center retrospective study suggests that older age of onset, headache, and leukocytosis are more likely to be characteristics of male patients with EBV-IM. Our study also underscores the importance of periorbital edema as a clue for early diagnosis of EBV-IM, especially in female patients.

Clinical prediction of complicated appendicitis: A case-control study utilizing logistic regression.

BACKGROUND: Since high-quality evidence on conservative treatment of acute appendicitis using antibiotics has increased, differentiation of patients with complicated appendicitis (CA) from those with simple appendicitis (SA) has become increasingly important. Previous studies have revealed that male gender, advanced age, comorbid conditions, prehospital delay, fever, and anorexia are risk factors of perforated appendicitis. Elevated serum C-reactive protein (CRP) level and hyponatremia have also been reported as predictive biomarkers of CA. However, confounding between various factors is problematic because most previous studies were limited to univariate analysis. AIM: To evaluate non-laboratory and laboratory predictive factors of CA using logistic regression analyses. METHODS: We performed an exploratory, single-center, retrospective case-control study that evaluated 198 patients (83.9%) with SA and 38 patients (16.1%) with CA. Diagnoses were confirmed by computed tomography images for all cases. We compared age, sex, onset-to-visit interval, epigastric/periumbilical pain, right lower quadrant pain, nausea/vomiting, diarrhea, anorexia, medical history (of previous non-surgically treated appendicitis, diabetes, hypertension, dyslipidemia, liver cirrhosis, hemodialysis, chronic lung diseases, malignant tumors, immunosuppressant use, and antiplatelet use), vital signs, physical findings, and laboratory data to select the explanatory variates for logistic regression. Based on the univariate comparisons, we performed logistic regression for clinical differentiation between CA and SA using only non-laboratory factors and also including both non-laboratory and laboratory factors. RESULTS: The 236 eligible patients consisted of 198 patients (83.9%) with SA and 38 patients (16.1%) with CA. The median ages were 34 years old [interquartile ranges (IR), 24-45 years] in the SA group and 49 years old (IR, 35-63 years) in the CA group (P < 0.001). The median onset-to-visit interval was 1 d (IR, 0-1) and 1 d (IR, 1-2) in the SA and CA groups, respectively (P < 0.001). Heart rate, body temperature, and serum CRP level in the CA group were significantly higher than in the SA group; glomerular filtration rate and serum sodium were significantly lower in the CA group. Anorexia was significantly more prevalent in the CA group. The regression model including age, onset-to-visit interval, anorexia, tachycardia, and fever as non-laboratory predictive factors of CA (Model 1) showed that age ≥ 65 years old, longer onset-to-visit interval, and anorexia had significantly high odds ratios. The logistic regression for prediction of CA including age, onset-to-visit interval, anorexia, serum CRP level, hyponatremia (serum sodium < 135 mEq/L), and glomerular filtration rate < 60 mL/min/1.73 m2 (Model 2) showed that only elevated CRP levels had significantly high odds ratios. Under the curve values of receiver operating characteristics curves of each regression model were 0.74 for Model 1 and 0.87 for Model 2. CONCLUSION: Our logistic regression analysis on differentiating factors of CA from SA showed that high CRP level was a strong dose-dependent predictor of CA.

Rapid, simple, and clinically applicable high-performance liquid chromatography method for clinical determination of plasma colistin concentrations.

BACKGROUND: Since both the antibacterial effects and common adverse effects of colistin are concentration-dependent, determination of the most appropriate dosage regimen and administration method for colistin therapy is essential to ensure its efficacy and safety. We aimed to establish a rapid and simple high-performance liquid chromatography (HPLC)-based system for the clinical determination of colistin serum concentrations. METHODS: Extraction using a solid-phase C18 cartridge, derivatisation with 9-fluorenylmethyl chloroformate, and elution with a short reversed-phase Cl8 column effectively separated colistin from an internal standard. The HPLC apparatus and conditions were as follows: analytical column, Hydrosphere C18; sample injection volume, 50 µL; column temperature, 40 °C; detector, Shimadzu RF-5300 fluorescence spectrophotometer (excitation wavelength, 260 nm; emission wavelength, 315 nm); mobile phase, acetonitrile/tetrahydrofuran/distilled water (50,14,20, v/v/v); flow-rate, 1.6 mL/min. RESULTS: The calibration curves obtained for colistin were linear in the concentration range of 0.10-8.0 µg/mL. The regression equation was y = 0.6496× - 0.0141 (r2 = 0.9999). The limit of detection was ~ 0.025 µg/mL, and the assay intra- and inter-day precisions were 0.87-3.74% and 1.97-6.17%, respectively. The analytical peaks of colistin A, colistin B, and the internal standard were resolved with adequate peak symmetries, and their retention times were approximately 8.2, 6.8, and 5.4 min, respectively. Furthermore, the assay was successfully applied to quantify the plasma colistin levels of a haemodialysis patient. CONCLUSION: The assay is a simple, rapid, accurate, selective, clinically applicable HPLC-based method for the quantification of colistin in human plasma.

Fever of unknown origin successfully treated by oren-gedoku-to (huanglian-jie-du-tang).

Oren-gedoku-to is a traditional medicine used for treating inflammatory conditions and is given by prescription in Japan, People's Republic of China, and Korea. Its anti-inflammatory effect is related to the arachidonate cascade and inhibition of cyclo-oxygenase, but research on other anti-inflammatory pathways is ongoing. We report a case of fever of unknown origin in a 33-year-old woman. The possibility of infection due to human immunodeficiency virus, autoimmune, neoplastic, or other disease was examined and excluded. Oren-gedoku-to was successfully used to treat her symptoms and may thus be a suitable treatment for patients with undiagnosed fever of unknown origin.

Successful treatment with pneumonectomy for pulmonary Mycobacterium abscessus infection.

We report a case of pulmonary Mycobacterium abscessus (M. abscessus) infection with destructive growth in the entire right lung. The patient was 56-year-old woman who had had pulmonary tuberculosis at the age of 40 and had been diagnosed as having pulmonary Mycobacterium abscessus infection 4 years prior to admission at our hospital. Although various antibiotics were administered, persistent fever, hemoptysis and weight loss developed. After undergoing a right pneumonectomy, her clinical symptoms improved dramatically and sputum excretions of M. abscessus ceased. No relapse of the disease has been observed in the 2 years since surgery. Pneumonectomy was very effective for refractory M. abscessus infection that destroyed the right lung.