Evaluation of NG-Test CARBA 5 version 2, Cepheid Xpert Carba-R, and carbapenem inactivation methods in comparison to whole-genome sequencing for the identification of carbapenemases in non-fermenting Gram-negative bacilli

NG-Test CARBA 5 (NG-Biotech) is a rapid in vitro multiplex immunoassay for the phenotypic detection and differentiation of the "big five" carbapenemase families (KPC, OXA-48-like, VIM, IMP, and NDM). Version 2 of this assay was evaluated alongside the Xpert Carba-R assay (Cepheid, Inc.), the modified carbapenem inactivation method (mCIM), and the CIMTris assay, with a collection of carbapenem-resistant non-fermenting Gram-negative bacilli comprising 138 Pseudomonas aeruginosa and 97 Acinetobacter baumannii isolates. Whole-genome sequencing (WGS) was used as the reference standard. For P. aeruginosa, NG-Test CARBA 5 produced an overall percentage agreement (OPA) with WGS of 97.1%, compared with 92.8% forXpert Carba-R and 90.6% for mCIM. For A. baumannii, as OXA-type carbapenemases (non-OXA-48) are not included, both the NG-Test CARBA 5 and Xpert Carba-R only had an OPA of 6.2%, while the CIMTris performed well with an OPA of 99.0%. The majority of A. baumannii isolates (95.9%) tested falsely positive for IMP on NG-Test CARBA 5; no IMP genes were found on WGS. No clear cause was found for this phenomenon; a cross-reacting protein antigen unique to A. baumannii is a possible culprit. NG-Test CARBA 5 performed well for carbapenemase detection in P. aeruginosa. However, results from A. baumannii isolates should be interpreted with caution.

Innovative dual-function protective scope mask and filtration system for aerosol generating ENT scope procedures

Background

Aerosol-generating procedures (AGPs), such as nasoendoscopy, are considered high-risk during the COVID-19 pandemic due to risk of virus aerosol transmission. We aim to evaluate the efficacy of an innovative system in reduction of aerosol contamination.

Methods

Pilot study involving 15 healthy volunteers performing aerosol-generating activities with the prototype, compared with and without a standard surgical mask.

Results

We found an increased frequency of smaller-sized particle emissions for all four expiratory activities. The particle emission rate with the prototype mask was significantly slower over time for the smallest sized particle (0.3 μm) during breathing, speaking and singing compared with similar activities without the mask (p < .05). We found similar trends for coughing for larger particles but that did not reach statistical significance.

Conclusion

The innovation offers good protection against aerosol transmission through the physical barrier of the mask, the negative pressure environment within the mask, and the unit's dual filtration function.

Level of evidence

Level 2b.

The first nosocomial cluster of COVID-19 due to the Delta variant in a major acute-care hospital in Singapore - investigations and outbreak response

OBJECTIVES

The first large nosocomial cluster of COVID-19 in Singapore in April 2021 led to partial closure of a major acute-care hospital. We report our investigations and evaluate the effectiveness of the BNT162.b2 and mRNA1273 vaccines against the Delta variant.

METHODS

Close contacts of COVID-19 patients and the affected ward were identified and underwent surveillance for SARS-CoV-2 infection. Patient, staff and visitor cohorts were constructed and factors associated with infection evaluated. Phylogenetic analysis of patient samples was performed. Ward air exhaust filters were tested for SARS-CoV-2 virus.

RESULTS

There were 47 cases in total, comprising 29 patients, 9 staff, 6 ward visitors and 3 household contacts. All infections were of the Delta variant. Ventilation studies showed turbulent airflow and swabs from air exhaust filters were positive for SARS-Cov2. Vaccine breakthrough infections were seen in both patients and staff. Among patients, vaccination was associated with a 79% lower odds of infection with COVID-19 (adjusted OR =0.21, 95%CI 0.05-0.95) CONCLUSIONS: This cluster occurred despite an enhancement in infection control measures that the hospital had undertaken at the onset of this pandemic, but it was rapidly brought under control through case isolation, extensive contact tracing and quarantine measures, and led to enhancements in hospital personal protective equipment (PPE) use, introduction of routine rostered testing of inpatients and staff, and hospital infrastructure changes to improve ventilation within the general ward.

Household transmission of carbapenemase-producing Enterobacteriaceae: a prospective cohort study

OBJECTIVES

To estimate the transmission rate of carbapenemase-producing Enterobacteriaceae (CPE) in households with recently hospitalized CPE carriers.

METHODS

We conducted a prospective case-ascertained cohort study. We identified the presence of CPE in stool samples from index subjects, household contacts and companion animals and environmental samples at regular intervals. Linked transmissions were identified by WGS. A Markov model was constructed to estimate the household transmission potential of CPE.

RESULTS

Ten recently hospitalized index patients and 14 household contacts were included. There were seven households with one contact, two households with two contacts, and one household with three contacts. Index patients were colonized with blaOXA-48-like (n = 4), blaKPC-2 (n = 3), blaIMP (n = 2), and blaNDM-1 (n = 1), distributed among divergent species of Enterobacteriaceae. After a cumulative follow-up time of 9.0 years, three family members (21.4%, 3/14) acquired four different types of CPE in the community (hazard rate of 0.22/year). The probability of CPE transmission from an index patient to a household contact was 10% (95% CI 4%-26%).

CONCLUSIONS

We observed limited transmission of CPE from an index patient to household contacts. Larger studies are needed to understand the factors associated with household transmission of CPE and identify preventive strategies.

Coronavirus Disease 2019 (COVID-19): The Singapore Experience. A Review of the First Eight Months

As of 27 October 2020, there have been 57,980 confirmed cases of COVID-19 in Singapore, with 28 fatalities. To summarise the Singapore experience in managing and containing COVID-19 based on available published data and from relevant sources, a review of literature using research databases such as PubMed and OVID Medline, along with non-peer-reviewed articles and other sources, was conducted with the search terms ‘COVID-19’ and ‘Singapore’. Research conducted in Singapore has provided insight into the clinical manifestations and period of infectivity of COVID-19, demonstrated evidence of pre-symptomatic transmission, linked infection clusters using serological tools, and highlighted aspects of hospital-based environmental contamination. It has also provided guidance for diagnostic testing and has described immune and virologic correlates with disease severity. Evidence of effectiveness of containment measures such as early border control, rigorous contact training, and calibrated social distancing measures have also been demonstrated. Singapore’s multipronged strategy has been largely successful at containing COVID-19 and minimising fatalities, but the risk of re-emergence is high. Keywords: Epidemiology, management, prevention, transmission

Coronavirus Disease 2019 (COVID-19): The Singapore Experience. A Review of the First Eight Months

As of 27 October 2020, there have been 57,980 confirmed cases of COVID-19 in Singapore, with 28 fatalities. To summarise the Singapore experience in managing and containing COVID-19 based on available published data and from relevant sources, a review of literature using research databases such as PubMed and OVID Medline, along with non-peer-reviewed articles and other sources, was conducted with the search terms 'COVID-19' and 'Singapore'. Research conducted in Singapore has provided insight into the clinical manifestations and period of infectivity of COVID-19, demonstrated evidence of pre-symptomatic transmission, linked infection clusters using serological tools, and highlighted aspects of hospital-based environmental contamination. It has also provided guidance for diagnostic testing and has described immune and virologic correlates with disease severity. Evidence of effectiveness of containment measures such as early border control, rigorous contact training, and calibrated social distancing measures have also been demonstrated. Singapore's multipronged strategy has been largely successful at containing COVID-19 and minimising fatalities, but the risk of re-emergence is high.

Neuroimaging in Zoonotic Outbreaks Affecting the Central Nervous System: Are We Fighting the Last War?

When preparing for the coronavirus disease 2019 pandemic and its effects on the CNS, radiologists should be familiar with neuroimaging appearances in past zoonotic infectious disease outbreaks. Organisms that have crossed the species barrier from animals to humans include viruses such as Hendra, Nipah, Severe Acute Respiratory Syndrome, and influenza, as well as bacteria and others. Brain CT and MR imaging findings have included cortical abnormalities, microinfarction in the white matter, large-vessel occlusion, and features of meningitis. In particular, the high sensitivity of diffusion-weighted MR imaging in detecting intracranial abnormalities has been helpful in outbreaks. Although the coronaviruses causing the previous Severe Acute Respiratory Syndrome outbreak and the current coronavirus disease 19 pandemic are related, it is important to be aware of their similarities as well as potential differences. This review describes the neuroimaging appearances of selected zoonotic outbreaks so that neuroradiologists can better understand the current pandemic and potential future outbreaks.

Transmission modes of severe acute respiratory syndrome coronavirus 2 and implications on infection control: a review

The complete picture of transmission modes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. This review summarises the available evidence of its transmission modes, our preliminary research findings and implications on infection control policy, and outlines future research directions. Environmental contamination has been reported in hospital settings occupied by infected patients, and is higher in the first week of illness. Transmission via environmental surfaces or fomites is likely, but decontamination protocols are effective in minimising this risk. The extent of airborne transmission is also unclear. While several studies have detected SARS-CoV-2 RNA in air samples, none has isolated viable virus in culture. Transmission likely lies on a spectrum between droplet to airborne transmission depending on patient, disease and environmental factors. Singapore's current personal protective equipment and isolation protocols are sufficient to manage this risk.

Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients

Understanding the particle size distribution in the air and patterns of environmental contamination of SARS-CoV-2 is essential for infection prevention policies. Here we screen surface and air samples from hospital rooms of COVID-19 patients for SARS-CoV-2 RNA. Environmental sampling is conducted in three airborne infection isolation rooms (AIIRs) in the ICU and 27 AIIRs in the general ward. 245 surface samples are collected. 56.7% of rooms have at least one environmental surface contaminated. High touch surface contamination is shown in ten (66.7%) out of 15 patients in the first week of illness, and three (20%) beyond the first week of illness (p = 0.01, χ² test). Air sampling is performed in three of the 27 AIIRs in the general ward, and detects SARS-CoV-2 PCR-positive particles of sizes >4 µm and 1-4 µm in two rooms, despite these rooms having 12 air changes per hour. This warrants further study of the airborne transmission potential of SARS-CoV-2.

FluMob: Enabling Surveillance of Acute Respiratory Infections in Health-care Workers via Mobile Phones

Singapore is a hotspot for emerging infectious diseases and faces a constant risk of pandemic outbreaks as a major travel and health hub for Southeast Asia. With an increasing penetration of smart phone usage in this region, Singapore's pandemic preparedness framework can be strengthened by applying a mobile-based approach to health surveillance and control, and improving upon existing ideas by addressing gaps, such as a lack of health communication. FluMob is a digitally integrated syndromic surveillance system designed to assist health authorities in obtaining real-time epidemiological and surveillance data from health-care workers (HCWs) within Singapore, by allowing them to report influenza incidence using smartphones. The system, integrating a fully responsive web-based interface and a mobile interface, is made available to HCW using various types of mobile devices and web browsers. Real-time data generated from FluMob will be complementary to current health-care- and laboratory-based systems. This paper describes the development of FluMob, as well as challenges faced in the creation of the system.

Mycotic aneurysm due to Burkholderia pseudomallei infection: case reports and literature review

Melioidosis caused by Burkholderia pseudomallei infection is endemic in Southeast Asia and Northern Australia. Cardiovascular complications resulting in mycotic aneurysms are very rare. To our knowledge, there have only been 6 isolated case reports published in the literature to date. We report 6 cases of melioidosis in Singapore that presented as aortic aneurysms.

Eikenella corrodens discitis after spinal surgery: case report and literature review

Eikenella corrodens is part of the normal flora of the mouth and upper respiratory tract and is usually associated with dental and head and neck infections. We report a case of Eikenella discitis occurring soon after spinal surgery in an otherwise healthy patient, review the literature on bone and joint infections unrelated to human bites and fist-fight injuries, and stress the importance of definitive diagnosis in post-operative spinal infections.