Verification of Infection Prevention Control Using a Spatial Random Walk Model

To stop pandemic of the 2019 novel coronavirus (COVID-19), "an 80 percent reduction of person to person contact opportunities" was proposed by the Japanese government. This guideline was based on the result of macroscopic differential equation model akin to the SIR (Susceptible-Infected-Recovered) model. For the purpose of indicating person to person’s infection mechanism intuitively, we built a new model to calculate infections between two persons who are in contact each other. This model adopted a spatial random walk model to express random movement of people in a specific 2-D geographical space. This model was applied to verify the effect of the proposed infection control procedure, "80 percent reduction". The result of the numerical simulation supported a proposed infection control procedure of "an 80 percent reduction" derived by the SIR model.

An unusual Staphylococcus saccharolyticus spondylodiscitis post vertebroplasty, a case report

Background: Staphylococcus saccharolyticus is a rarely encountered coagulase-negative slowly grower and strictly anaerobic staphylococcus from the skin. It is usually considered as a contaminant, but some rare reports describe deep-seated infections. Virulence factors remain poorly known although genomic analysis highlight pathogenic potential.Case presentation: we report a case of Staphylococcus saccharolyticus spondylodiscitis that followed kyphoplasty, a procedure associated with a low rate of sometimes severe infectious complication (0.46%) and we reviewed the literature. This case specifically stresses the risk of S. saccharolyticus health-care associated infection in patients of poor condition.Conclusion: infection to S. saccharolyticus is difficult to diagnose due to microbiological characteristics of this bacterium, requires timely treatment and improved infection control procedure should be encouraged for patients with poor condition.

Carriage of Multiple Subtypes of Methicillin-ResistantStaphylococcus aureusby Intensive Care Unit Patients

Objective:To determine how consistently patients are colonized with methicillin-resistantStaphylococcus aureus(MRSA) at various sites and how many subtypes can be carried simultaneously by a single patient.Setting.A 28-bed Intensive care unit in a tertiary-care referral hospital.Methods.A total of 1,181 patients were screened by culture of swab specimens obtained from the nose, throat, groin, and axilla on admission to the intensive care unit (ICU), twice weekly during their ICU stay, and at discharge.Results.MRSA was isolated at least once from 224 patients. Of these isolates, 359 were selected from 32 patients to be subtyped using pulsed-field gel electrophoresis. The rate of compliance with collection of swab specimens was 79.9%. The combination of sites colonized varied frequently over time for many patients. Of patients who had swab specimens obtained twice in 1 day, 8.7% had discordant results from the 2 swab sets. No patient had a clinical isolate that was not of an identical subtype to an isolate from an anatomical site that was sampled for screening. Half the patients carried multiple subtypes during their stay, with up to 4 subtypes per patient.Conclusions.The findings of this study may indicate that these patients have been colonized with MRSA on more than one occasion, possibly because of multiple breaches in infection control procedure. In MRSA-colonized patients, anatomical sites were intermittently colonized and carriage of multiple subtypes was common. These findings indicate that MRSA carriage is not a fixed state but may vary over time.

Efficacy of rubber dam isolation as an infection control procedure in paediatric dentistry

The efficacy of rubber dam, antiseptic mouth rinse and both procedures together in controlling atmospheric bacterial contamination during conservative procedures in the paedodontic clinic at Tanta University was assessed. Distribution of bacterial contamination varied depending on the position of the tooth in the mouth. The highest airborne bacterial contamination was found on the plates positioned on the patient’s chest. There was 98.8% bacterial reduction at 1 metre when rubber dam was used. This reduction increased when antiseptic mouth rinse was used before rubber dam application. Bacterial contamination fell sharply with increased distance from the head-rest