Microbiological findings and prescribing trends in SARS- CoV-2 positive patients in two United Kingdom Hospitals

Objective: To describe antibiotic prescribing and microbiological findings in patients admitted to two London hospitals with COVID-19. Methods: This is a retrospective review of confirmed SARS-CoV-2 infected adults admitted between 9th February and 10th May 2020. Demographics, critical care unit (CCU) admission, antibiotic prescribing and microbiology results within 10 days of COVID-19 diagnosis were analysed. Results: 1155 patients were identified. 32.9% (380) died. 12.4% (143) had positive microbiology. After excluding likely contaminants, 6.9% (80) had clinically significant microbiology. The most common organisms isolated from blood cultures were Escherichia coli 9.5% (7), Klebsiella pneumoniae 4.0% (3), and Staphylococcus aureus 2.7% (2). A high percentage of blood cultures yielded coagulase negative staphylococci (51/74, 68.9%) and likely represented contamination. Organisms isolated from lower respiratory tract samples included Candida albicans 44.4% (12), Staphylococcus aureus 22.2% (6), Klebsiella species 11.0% (3), Pseudomonas aeruginosa 11.0% (3), and Citrobacter species 11% (3). Legionella and pneumococcal urinary antigen tests were positive in 0/117 and 2/71 (2.8%) samples. 91% (1051) of patients received antibiotics. Clarithromycin (24.2% total antibiotic use) and amoxicillin (21%) were most frequently used, followed by piperacillin-tazobactam (12.6%), gentamicin (10.6%), co-amoxiclav (9.3%) and meropenem (3.2%). Piperacillin-tazobactam or meropenem use was associated with a higher length of stay and mortality. Conclusions: Positive microbiology in COVID-19 patients is uncommon. Antibiotic use was widespread, despite lack of microbiological evidence of co-infection. When present, positive microbiology was more likely due to gram negative bacteria. Current local clinical and antimicrobial guidelines have incorporated these findings and recommend against routine antibiotic use in COVID-19 patients

Quantum-Hall activation gaps in graphene

We have measured the quantum-Hall activation gaps in graphene at filling factors $\nu=2$ and $\nu=6$ for magnetic fields up to 32 T and temperatures from 4 K to 300 K. The $\nu =6$ gap can be described by thermal excitation to broadened Landau levels with a width of 400 K. In contrast, the gap measured at $\nu=2$ is strongly temperature and field dependent and approaches the expected value for sharp Landau levels for fields $B > 20$ T and temperatures $T > 100$ K. We explain this surprising behavior by a narrowing of the lowest Landau level.Comment: 4 pages, 4 figures, updated version after review, accepted for PR

The Politics of Mainstreaming

Svrha rada. Ustanoviti razliku u višestrukim mjerenjima broja B linija u opažača s niskom razinom iskustva u plućnoj sonografiji te utvrditi mogućnost reproducibilnosti rezultata. Ispitanici i postupci. Istraživanje je provedeno na četrdeset mehanički ventiliranih pacijenata u jedinici intenzivnog liječenja starijih od 18 godina. Ultrazvučni pregled pluća izveden je u medioklavikularnoj liniji lijevog i desnog hemitoraksa, u drugom i četvrtom interkostalnom prostoru. Izbrojen je ukupan maksimalan broj B linija vidljivih na ekranu u jednom trenutku s time da prikaz i evaluacija nisu trajali duže od deset sekundi. Nakon petnaest minuta se pregled ponovio. Rezultati. Istraživanje je pokazalo da je opažač očitovao prosječno veće vrijednosti broja B linija u drugom mjerenju nego u prvom, ali ta razlika nije statistički značajna (P=0.083). Zaključak. Ne postoji statistički značajna razlika u broju B linija pri višetrukim pregledima pluća u opažaća s niskom razinom iskustva.Objectives. The purpose of this research was to determine intra-rater reliability of quantifying B-lines in an observer with a low level of experience in pulmonary sonography and to determine the possibility of reproducibility of this results. Methods. The study was conducted on forty mechanically ventilated patients in an intensive care unit aged above eighteen. The ultrasound lung examination was performed in the medioclavicular line of the left and right hemithorax , in the second and fourth intercostal space. The total number of B lines displayed on the screen was counted. Quantification lasted less than ten seconds. After fifteen minutes, the examination was repeated. Results. The study showed that the observer had averaged higher values in the second measurement than in the first, but that difference was not statistically significant (P = 0.083). Conclusion. There is no statistically significant intra-observer difference in the number of B lines quantified in the observer with a low experience level

Gap opening in the zeroth Landau level of graphene

We have measured a strong increase of the low-temperature resistivity $\rho_{xx}$ and a zero-value plateau in the Hall conductivity $\sigma_{xy}$ at the charge neutrality point in graphene subjected to high magnetic fields up to 30 T. We explain our results by a simple model involving a field dependent splitting of the lowest Landau level of the order of a few Kelvin, as extracted from activated transport measurements. The model reproduces both the increase in $\rho_{xx}$ and the anomalous $\nu=0$ plateau in $\sigma_{xy}$ in terms of coexisting electrons and holes in the same spin-split zero-energy Landau level.Comment: 4 pages, 3 figure