A case of Citrobacter koseri renal abscess and review of the literature.

Citrobacter species are anaerobic gram-negative bacteria that are known to cause infections in immunocompromised hosts, particularly in hospital settings. Their opportunistic nature and tendency to develop antibiotic resistance make Citrobacter species challenging to treat. Renal or perinephric abscess formation as a result of Citrobacter infection is uncommon, having only previously been reported in four cases. We present a case of a 70-year-old man with diabetes and prostate cancer who was diagnosed with an 18 cm perinephric and a 10 cm perihepatic abscess caused by Citrobacter koseri. The patient required drains and re-positioning of the drains multiple times in addition to a prolonged course of antibiotics to achieve complete radiographic resolution. This case highlights the challenges in treating renal and perinephric abscess, as it required drain re-placements two additional times after the initial placement and an additional 4 weeks of antibiotics. Successful treatment for larger abscesses usually requires a two-arm approach, with antibiotics in combination with either percutaneous or surgical abscess drainage.

SARS-CoV-2 can infect human embryos.

The spread of SARS-CoV-2 has led to a devastating pandemic, with infections resulting in a range of symptoms collectively known as COVID-19. The full repertoire of human tissues and organs susceptible to infection is an area of active investigation, and some studies have implicated the reproductive system. The effects of COVID-19 on human reproduction remain poorly understood, and particularly the impact on early embryogenesis and establishment of a pregnancy are not known. In this work, we explore the susceptibility of early human embryos to SARS-CoV-2 infection. By using RNA-seq and immunofluorescence, we note that ACE2 and TMPRSS2, two canonical cell entry factors for SARS-CoV-2, are co-expressed in cells of the trophectoderm in blastocyst-stage preimplantation embryos. For the purpose of viral entry studies, we used fluorescent reporter virions pseudotyped with Spike (S) glycoprotein from SARS-CoV-2, and we observe robust infection of trophectoderm cells. This permissiveness could be attenuated with blocking antibodies targeting S or ACE2. When exposing human blastocysts to the live, fully infectious SARS-CoV-2, we detected cases of infection that compromised embryo health. Therefore, we identify a new human target tissue for SARS-CoV-2 with potential medical implications for reproductive health during the COVID-19 pandemic and its aftermath.

Clinical guideline highlights for the hospitalist: Prevention and treatment of venous thromboembolism in hospitalized patients with cancer.

GUIDELINE TITLE: American Society of Hematology 2021 Guidelines for Management of Venous Thromboembolism: Prevention and Treatment in Patients with Cancer RELEASE DATE: February 23, 2021 PRIOR VERSION(S): n/a DEVELOPER: American Society of Hematology FUNDING SOURCE: American Society of Hematology TARGET POPULATION: Adult patients with cancer.

A Case of Native Joint Septic Arthritis Caused by Bacteroides fragilis.

BACKGROUND Bacteroides fragilis (B. fragilis) is an uncommon cause of native joint septic arthritis (NJSA). It is an anaerobic gram-negative rod that is normally found in the oral cavity, gastrointestinal tract, genitourinary system, and skin, and thus is rarely isolated from the musculoskeletal system. Risk factors for B. fragilis NJSA include inflammatory arthritis, malignancy, sickle cell disease, and ischemic heart disease. CASE REPORT We discuss a case of a 65-year-old man with coronary artery disease, heart failure, chronic kidney disease, and gout, who presented with 5 days of right knee pain, redness, swelling, and warmth. His history included a corticosteroid injection in the affected knee 2 months prior to presentation. The patient was febrile with a palpable right knee joint effusion on exam. Labs were significant for leukocytosis and elevated inflammatory markers. Synovial fluid was aspirated, which was diagnostic for septic arthritis, with cultures growing B. fragilis. Blood cultures were negative, so the infection was attributed to the prior joint injection. The patient was subsequently taken to the operating room for irrigation and debridement. He was started on metronidazole, but he unfortunately left against medical advice before treatment was complete and was lost to follow-up thereafter. CONCLUSIONS B. fragilis NJSA most often occurs in the setting of bacteremia or contiguous spread from a concomitant infection. Management involves antibiotics such as metronidazole and surgical drainage. Due to the paucity of data on an infection such as in the present case, the optimal duration of metronidazole is not well-established.

Clostridium difficile appendicitis in an immunocompromised patient: a case report and review of the literature.

BACKGROUND: Clostridium difficile (C. difficile) is a common cause of infectious colitis in individuals with prior antibiotic or hospital exposure. Extraintestinal manifestations of C. difficile infections, however, are rare. Here we present a case of C. difficile appendicitis in an immunocompromised patient. CASE PRESENTATION: A 53-year-old Caucasian male presented to the emergency room for two days of lower abdominal pain associated with nausea and subjective fevers. He otherwise denied having diarrhea or hematochezia. He did not have any recent hospitalizations, nursing home stays, or antibiotic exposure. His past medical history was notable for stage III tonsillar squamous cell carcinoma for which he was status post tonsillectomy, radiation therapy, and chemotherapy (cisplatin 4 days prior to presentation). He was afebrile with tenderness to palpation in the bilateral lower quadrants, right greater than left. His white blood cell (WBC) count was 15.6 × 103 cells/µL. Computed tomography (CT) of the abdomen and pelvis showed marked edema and inflammation of the cecum and ascending colon as well as an enlarged appendix with surrounding inflammatory changes with a small amount of free fluid in the right paracolic gutter. He was treated non-surgically with antibiotics. He did not clinically improve and on hospital day 3, he developed diarrhea for which C. difficile stool polymerase chain reaction was sent. Repeat CT of the abdomen and pelvis was performed which showed progression to pan-colitis and persistent appendicitis. C. difficile testing later resulted positive, for which oral vancomycin was started. The patient markedly improved with medical management alone and was subsequently discharged on oral vancomycin. CONCLUSIONS: Our case highlights the importance of maintaining a high index of suspicion for C. difficile in a patient presenting with both appendicitis and colitis, with prompt diagnosis and treatment being essential.

Benchmarking Single-Cell mRNA-Sequencing Technologies Uncovers Differences in Sensitivity and Reproducibility in Cell Types With Low RNA Content.

Single-cell RNA sequencing (scRNA-seq) has the ability to classify each cell and determine the transcriptomic profile of specific cell types and cells of a given disease state; however, sensitivity of the gene count for each cell can be a critical component to the success of a single-cell study. The recently introduced SMART-Seq Single Cell PLUS Kit (SSsc PLUS) claims to provide higher sensitivity and reproducibility versus popular methods for the sequencing analysis of single cells. Here, the cDNA-generation component of the kit, SMART-Seq Single Cell Kit (SSsc), was compared with the popular homebrew protocol, Smart-seq2, and its update, Smart-seq3. The SMART-Seq Library Prep Kit from SSsc PLUS was benchmarked against a commonly used scRNA-seq library preparation method, Illumina Nextera XT. Finally, the SSsc chemistry was tested in both full and fractional volumes on 2 popular liquid-handler devices to investigate whether the high sensitivity was maintained in miniaturization. We demonstrate that SSsc PLUS outperforms these other full-length methods in convenience, sensitivity, gene identification, and reproducibility while also offering full compatibility with automation platforms.