Overview of Antibiotic Prophylaxis in Orthopaedic and Cardiac Procedures.

Antibiotic prophylaxis (AP) in surgical procedures is commonly used to prevent infections that may occur after operations. There are multiple factors that can contribute to increased risk of postsurgical complications that include prolonged hospitalization, reoperation, and readmissions. One of the strategies of decreasing the risk of bacterial contamination and developing infections is preprocedural antibiotic administration. When selecting an appropriate antibiotic, it is important to take into account surgery type and patient's characteristics which would also impact timing of administration and prophylaxis duration. Although surgical AP is significant for avoiding bacterial complications, it is also associated with some drawbacks such as increased antibiotic resistance and development of adverse reactions. Therefore, it is important to assess risks and benefits and select the most appropriate antibiotic regimen before initiating AP.

KaryoCreate: A CRISPR-based technology to study chromosome-specific aneuploidy by targeting human centromeres.

Aneuploidy, the presence of chromosome gains or losses, is a hallmark of cancer. Here, we describe KaryoCreate (karyotype CRISPR-engineered aneuploidy technology), a system that enables the generation of chromosome-specific aneuploidies by co-expression of an sgRNA targeting chromosome-specific CENPA-binding ɑ-satellite repeats together with dCas9 fused to mutant KNL1. We design unique and highly specific sgRNAs for 19 of the 24 chromosomes. Expression of these constructs leads to missegregation and induction of gains or losses of the targeted chromosome in cellular progeny, with an average efficiency of 8% for gains and 12% for losses (up to 20%) validated across 10 chromosomes. Using KaryoCreate in colon epithelial cells, we show that chromosome 18q loss, frequent in gastrointestinal cancers, promotes resistance to TGF-ß, likely due to synergistic hemizygous deletion of multiple genes. Altogether, we describe an innovative technology to create and study chromosome missegregation and aneuploidy in the context of cancer and beyond.

A Family of Small Intrinsically Disordered Proteins Involved in Flagellum-Dependent Motility in Salmonella enterica.

By screening a collection of Salmonella mutants deleted for genes encoding small proteins of ≤60 amino acids, we identified three paralogous small genes (ymdF, STM14_1829, and yciG) required for wild-type flagellum-dependent swimming and swarming motility. The ymdF, STM14_1829, and yciG genes encode small proteins of 55, 60, and 60 amino acid residues, respectively. A bioinformatics analysis predicted that these small proteins are intrinsically disordered proteins, and circular dichroism analysis of purified recombinant proteins confirmed that all three proteins are unstructured in solution. A mutant deleted for STM14_1829 showed the most severe motility defect, indicating that among the three paralogs, STM14_1829 is a key protein required for wild-type motility. We determined that relative to the wild type, the expression of the flagellin protein FliC is lower in the ΔSTM14_1829 mutant due to the downregulation of the flhDC operon encoding the FlhDC master regulator. By comparing the gene expression profiles between the wild-type and ΔSTM14_1829 strains via RNA sequencing, we found that the gene encoding the response regulator PhoP is upregulated in the ΔSTM14_1829 mutant, suggesting the indirect repression of the flhDC operon by the activated PhoP. Homologs of STM14_1829 are conserved in a wide range of bacteria, including Escherichia coli and Pseudomonas aeruginosa We showed that the inactivation of STM14_1829 homologs in E. coli and P. aeruginosa also alters motility, suggesting that this family of small intrinsically disordered proteins may play a role in the cellular pathway(s) that affects motility.IMPORTANCE This study reports the identification of a novel family of small intrinsically disordered proteins that are conserved in a wide range of flagellated and nonflagellated bacteria. Although this study identifies the role of these small proteins in the scope of flagellum-dependent motility in Salmonella, they likely play larger roles in a more conserved cellular pathway(s) that indirectly affects flagellum expression in the case of motile bacteria. Small intrinsically disordered proteins have not been well characterized in prokaryotes, and the results of our study provide a basis for their detailed functional characterization.

Fulminant Shigellosis in a HIV Patient.

Infectious enterocolitis caused by shigella is usually self-limiting and seldom requires antibiotics treatment. It is uncommon to develop fulminant shigellosis requiring surgery. We report a rare case of fulminant shigellosis in a HIV patient with recurring infection which could not be managed with intravenous antibiotics. CT reviewed extensive colonic wall thickening and stranding with evidence of pneumatosis coli. The patient eventually required a Hartmann procedure. Although fulminant shigellosis is uncommon, thorough assessment and vigilant management are warranted in immunosuppressed patient.

Pneumoperitoneum in a non-acute abdomen-pneumatosis cystoides intestinalis.

AIM: The aim of this study is to increase the understanding of pneumatosis cystoides intestinalis (PCI) and its incidents. METHOD: We report here a case of PCI in an 88-year-old man with a provisional diagnosis of perforated viscus and possible ischaemic bowels based on CT findings of pneumoperitoneum. The patient was found to have extensive PCI on his small bowels. We then systematically search the PubMed database for case reports for articles containing 'pneumatosis intestinalis' in their titles or key words. RESULTS: The study group consisted of 52 cases on PCI from the period of 2010-2014 with the focus on the adult population. The youngest patient was 18 years old and the oldest was 91 years old. The mean age was 60.4 years (range, 18-91 years old). There were 27 (52 %) females and 25 (48 %) males. The most common symptoms were abdominal pain (79 %) followed by nausea/vomiting (27 %) and abdominal distension (19 %). CT imaging was the most common investigation modality used (94 %). Three (6 %) of the patients had laparoscopic treatment while 20 (38 %) had laparotomy. Thirty-six (69 %) of them recovered uneventfully while 9 (17 %) of the patients died. CONCLUSION: Although there have been more case reports published on PCI in the recent years, the understanding of this condition remains in the infancy stage. PCI can be difficult to diagnose and can be easily misdiagnosed as pneumoperitoneum in an acute abdomen. Often it is identified incidentally during operation. Asymptomatic PCI should be treated conservatively, while emergency laparotomy should be reserved for life threatening abdominal pathology.