Calcium polystyrene sulfonate-induced rectal ulcer causing E. coli native-valve infective endocarditis.

Escherichia coli-associated native-valve infective endocarditis is a rare disease that affects elderly patients with underlying risk factors such as diabetes mellitus, malignancy, and renal failure. Long-term use of calcium polystyrene sulfonate is a potential risk factor for gastrointestinal mucosal damage or even colorectal ulcers. Herein, we describe a fatal case of a 66-year-old Japanese man with diabetes mellitus and renal failure who was prescribed calcium polystyrene sulfonate (CPS) for 11 years and developed a CPS-induced rectal ulcer, leading to E. coli native-valve infective endocarditis. The patient was admitted to our hospital due to acute-onset impaired consciousness. As a result of the systemic investigation, he was diagnosed with E. coli bacteremia accompanied by multiple cerebral infarctions and an acute hemorrhagic rectal ulcer. Transesophageal echocardiography revealed a 20-mm vegetative structure on the mitral valve, resulting in a final diagnosis of E. coli-associated infective endocarditis. After rectal resection, mitral valve replacement surgery was performed; however, the patient died shortly after surgery. Pathological findings of the resected rectum showed deposition of a basophilic crystalline material suggesting the presence of CPS. Our case highlights the potential risk of colorectal ulcers in a long-term CPS user, which can trigger bacterial translocation and endocarditis as fatal complications.

Case Series of Granulicatella Bacteremia: A Single-centered, Five-year Retrospective Study.

Granulicatella species are rare, nutritionally variant streptococci that cause infective endocarditis. Their clinical and microbiological characteristics remain unknown. We reviewed five years of Granulicatella cases in our hospital database (Jan 2017-Jun 2022), finding 6 Granulicatella adiacens cases and 1 Granulicatella elegans case. Clinical backgrounds and bacteremia sources were diverse; 3 cases developed polymicrobial bacteremia. Antimicrobial testing showed non-susceptibility to penicillin G in 4 of 7 cases (57.1%), and high susceptibility to carbapenems and vancomycin in all cases. Determining optimal antibiotic therapy for Granulicatella infections is vital in this era of antimicrobial resistance.

Antimicrobial prescription practices for outpatients with acute respiratory tract infections: A retrospective, multicenter, medical record-based study.

Antimicrobial stewardship for outpatients with acute respiratory tract infections (ARTIs) should be urgently promoted in this era of antimicrobial resistance. Previous large-sample studies were based on administrative data and had limited reliability. We aimed to identify current antimicrobial prescription practices for ARTIs by directly basing on medical records. This multicenter retrospective study was performed from January to December in 2018, at five medical institutes in Japan. We targeted outpatients aged ≥18 years whose medical records revealed International Classification of Diseases (ICD-10) codes suggesting ARTIs. We divided the eligible cases into three age groups (18-64 years, 65-74 years, and ≥75 years). We defined broad-spectrum antimicrobials as third-generation cephalosporins, macrolides, fluoroquinolones, and faropenem. Primary and secondary outcomes were defined as the proportion of antimicrobial prescriptions for the common cold and other respiratory tract infections, respectively. Totally, data of 3,940 patients were collected. Of 2,914 patients with the common cold, 369 (12.7%) were prescribed antimicrobials. Overall, compared to patients aged ≥75 years (8.5%), those aged 18-64 years (16.6%) and those aged 65-74 years (12.1%) were frequently prescribed antimicrobials for the common cold (odds ratio [95% confidential interval]; 2.15 [1.64-2.82] and 1.49 [1.06-2.09], respectively). However, when limited to cases with a valid diagnosis of the common cold by incorporating clinical data, no statistical difference was observed among the age groups. Broad-spectrum antimicrobials accounted for 90.2% of the antimicrobials used for the common cold. Of 1,026 patients with other respiratory infections, 1,018 (99.2%) were bronchitis, of which antimicrobials were prescribed in 49.9% of the cases. Broad-spectrum antimicrobials were the main agents prescribed, accounting for nearly 90% of prescriptions in all age groups. Our data suggested a favorable practice of antimicrobial prescription for outpatients with ARTIs in terms of prescribing proportions, or quantitative aspect. However, the prescriptions were biased towards broad-spectrum antimicrobials, highlighting the need for further antimicrobial stewardship in the outpatient setting from a qualitative perspective.

Emergence of Daptomycin-Resistant Staphylococcus aureus during Treatment.

A 68-year-old man with persistent bacteremia accompanying a large iliopsoas abscess, vertebral osteomyelitis, discitis and central venous port infection caused by methicillin-resistant Staphylococcus aureus (MRSA) was admitted to our hospital. During the course of treatment, the emergence of a daptomycin (DAP)-resistant MRSA strain was confirmed; the minimum inhibitory concentration was 1 to 2 µg/mL for vancomycin and more than 1 µg/mL for DAP. Although the bacterial cell wall was not significantly thickened, an increased positive surface charge and single-nucleotide polymorphism within mprF have been confirmed in DAP-resistant strains. Still rare, but clinicians need to be cautious of the emergence of DAP-resistant MRSA during treatment.

Recurrent Stenotrophomonas maltophilia bacteremia after iliac crest bone graft harvest.

We describe a rare case of recurrent Stenotrophomonas maltophilia bacteremia in a previously healthy 45-year-old man. The infection was caused by osteomyelitis at the site of an iliac crest bone graft harvest. A genetic analysis using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) revealed that the blood isolates and pathogens obtained from the surgical wound were identical. Initial treatment with levofloxacin and cefozopran was ineffective, but the patient's infection was successfully treated by long-term administration of latamoxef and trimethoprim-sulfamethoxazole. The present case suggests that attention should be given to the possibility of S. maltophilia infection in any situations.

A new laser ablation system for quantitative analysis of solid samples with ICP-MS.

The laser ablation (LA) method is an effective technique for quantitative analysis. In the present work, a new LA system was developed for the high-sensitivity analysis of metal materials using inductively coupled plasma mass spectrometry (ICP-MS). This system consists of a high-frequency Q-switched laser and 2 scanning mirrors for scanning the ablation spot in an adequately large area of the specimen without vacant spaces. The influence of elemental fractionation (non-stoichiometric generation of vapor species) can be eliminated by repetitive irradiation of this pattern on the same area. Particles generated with an average laser power of 0.6 W with the developed LA system gave intensity and stability substantially similar to that of a 500 microg/ml solution steel sample in solution ICP-MS. The analytical performance of the developed LA-ICP-MS was compared with that of a solution ICP-MS using NIST steel SRMs. The performance of the newly-developed system is comparable to that of conventional solution ICP-MS in both accuracy and precision. The correlation coefficients between the contents and the intensity ratios to Fe were over 0.99 for most elements. The relative standard deviation (RSD) obtained by LA-ICP-MS revealed that this system can analyze iron samples with good precision. The results of ultra trace level analysis of high-purity iron showed that developed LA-ICP-MS is capable of analyzing ppm concentration levels with a 20 - 30 ppb level standard deviation. The detection limit was on the order of 10 ppb for most elements.