A case of left atrial intimal sarcoma with rhabdomyosarcoma differentiation: a case report and literature review.

Primary cardiac malignancies are rare, with cardiac sarcomas being the main type. Among these, intimal sarcomas are the most common. However, they tend to occur in the great vessels and are rare in the heart, with only a few isolated cases reported. We report a challenging case of a patient with left atrial intimal sarcoma with rhabdomyosarcoma differentiation. The patient was admitted after a physical examination detected left heart occupancy, and initial imaging suspected a left atrial thrombus. The patient then underwent extracorporeal circulation-assisted open cardiac surgery with resection of an atrial mass. The postoperative pathological findings were suggestive of an arterial intimal sarcoma, which included areas of rhabdomyosarcoma differentiation within the tumor tissue. Unfortunately, the patient's tumor recurred 4 months later, and she died due to treatment failure. This case highlights the rarity and risk of misdiagnosis of cardiac intimal sarcoma. Additionally, we aim to improve the understanding of intimal sarcoma through a review of immunohistochemistry and gene amplification techniques.

The prevalence and mechanisms of heteroresistance to ceftazidime/avibactam in KPC-producing Klebsiella pneumoniae.

OBJECTIVES: To investigate the prevalence and mechanisms of ceftazidime/avibactam heteroresistance in KPC-producing Klebsiella pneumoniae (KPC-KP) isolates, as well as the role of heteroresistance in the transition of ceftazidime/avibactam susceptibility to resistance. METHODS: Clinical KPC-KP isolates were obtained from a tertiary hospital in China from 2016 to 2017 and 2019 to 2020. Antimicrobial susceptibility was determined by the broth microdilution method. Population analysis profiles were used to assess ceftazidime/avibactam heteroresistance. WGS and molecular cloning were conducted to reveal heteroresistance mechanisms and molecular characteristics. RESULTS: The findings indicated that the transition of ceftazidime/avibactam susceptibility to resistance during the treatment of KPC-KP infection is primarily attributed to the heteroresistance exhibited by KPC-KP isolates towards ceftazidime/avibactam. Among 355 ceftazidime/avibactam-susceptible KPC-KP isolates (indicating a resistance rate of 0%), 41 (11.55%) exhibited ceftazidime/avibactam heteroresistance, with the primary mechanism being the presence of KPC mutant subpopulations. These KPC variants, arising from point mutations, deletions and insertions, significantly increased ceftazidime/avibactam resistance while alongside enhanced carbapenem susceptibility. Notably, 11 new KPC variants were identified. Furthermore, four heteroresistant isolates were caused by mixed infection involving subpopulations carrying NDM-1 or NDM-5. Phylogenetic analysis indicated that the clonal spread of ST11-KL64 KPC-KP may be correlated with the prevalence of heteroresistance. CONCLUSIONS: Ceftazidime/avibactam heteroresistance, primarily driven by pre-existing KPC variants, underscores the importance of considering heteroresistance in ceftazidime/avibactam therapeutics. Awareness of these dynamics is crucial for the effective and sustainable clinical application of ceftazidime/avibactam.

Fatal arrhythmia associated with novel coronavirus 2019 infection: Case report and literature review.

RATIONALE: The novel coronavirus of 2019 (COVID-19) has inflicted significant harm on the cardiovascular system. Patients presenting with fatal chronic arrhythmias after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are rare, arrhythmia caused by SARS-CoV-2 infection need to be taken seriously. PATIENT CONCERNS: Three female patients were admitted to the hospital with syncopal symptoms. Previously, they had been identified to have COVID-19 infection and none of the patients had a preexisting history of arrhythmia, and upon hospital admission, no electrolyte imbalances associated with arrhythmias were observed. However, following SARS-CoV-2 infection, patients exhibit varying degrees of syncope symptoms. DIAGNOSES: A high-degree atrioventricular block was diagnosed after a comprehensive evaluation of the patient's clinical manifestations and electrocardiogram (ECG) performance. INTERVENTIONS: We performed ECG monitoring of the patient and excluded other causes of arrhythmia. The patient was discharged from the hospital after permanent pacemaker implantation and symptomatic treatment. OUTCOMES: The outpatient follow-ups did not reveal a recurrence of syncope or complications related to the pacemaker in any of the three patients. LESSONS: Some patients did not exhibit any obvious respiratory symptoms or signs following SARS-CoV-2 infection. This suggests that the cardiac conduction system may be the preferred target for some SARS-CoV-2 variants. Therefore, in addition to investigating the causes of malignant arrhythmias, special attention should be paid to SARS-CoV-2 infection in patients with developing arrhythmias. Additionally, permanent pacemaker implantation may be the most suitable option for patients who already have malignant arrhythmias.

A Selective Medium for Screening Ceftazidime/Avibactam Resistance in Carbapenem-Resistant Enterobacterales.

Ceftazidime/avibactam (CZA) is an alternative antibiotic used for the treatment of infections caused by carbapenem-resistant Enterobacterales (CRE). However, the CZA-resistant CRE strains have been detected worldwide. Therefore, it is critical to screen CZA-resistant CRE strains in colonized patients or a specific population so as to rapidly implement infection control measures to limit their transmission. In this study, we developed a Salmonella-Shigella (SS) CZA-selective medium and assessed its performance to screen for clinical CZA-resistant CRE isolates in both pure-strain specimens and stool samples. A total of 150 non-duplicated isolates, including 75 CZA-susceptible and 75 CZA-resistant CRE pathogens, were tested by using the broth microdilution method and the SS CZA medium, respectively. The bacterial suspensions were serially diluted in the SS CZA medium, which showed excellent screening performance in both pure CZA-resistant CRE strain and the stool samples with the lowest detection limit of 101-102 and 101-103 CFU/ml, respectively. Notably, none of the susceptible isolates showed growth even at the highest dilution concentration of 108 CFU/ml. Most importantly, the SS CZA medium demonstrated excellent performance in screening simulated clinical polymicrobial specimens. Moreover, its screening performance was unaffected by the different resistance determinants for tested isolates. Cumulatively, our data suggest that the SS CZA medium can be used as a promising selective medium to screen CZA-resistant CRE, irrespective of their resistance mechanisms.

Optical design of a street lamp based on dual-module chip-on-board LED arrays.

We design and propose a compact street lamp based on dual-module chip-on-board LED. The street lamp is composed of six faceted reflectors. It can direct the luminous flux and form uniform illumination on the target area, and it effectively reduces power consumption. We have conducted both simulations and prototype measurements. The test results show good optical performance in that the uniformity of luminance reaches 0.58 for LED lamp zigzag arrangements and 0.60 for LED lamp double-side arrangements. The average luminance can fulfill the requirements in Chinese road lighting Standard CJJ45-2006.