Journal of Hospital Infection最新文献

Background: Ozonated water is expected to be an effective disinfectant for SARS-CoV-2 present on environmental fomites; however, ozone is consumed by organic substances, resulting in attenuation of its effect. SARS-CoV-2 present in saliva can contaminate environmental surfaces; therefore, it is essential to understand the effect of organic substances in saliva on the disinfectant properties of ozonated water.

Aim: To assess organic factors in saliva and the extent to which they diminish the effect of ozonated water on SARS-CoV-2.

Methods: Ozonated water was exposed to salivary organic factors and residual ozone concentrations were measured. SARS-CoV-2 was exposed to a salivary factor and virus inactivation by ozonated water was measured.

Findings: Amylase and mucin consumed ozone in a concentration-dependent manner. Urea did not. Ozonated water appeared to inactivate SARS-CoV-2 within 30 sec. The amount of inactivated SARS-CoV-2 decreased as the protein concentration increased. Virus inactivation was stronger by 1.5 mg/L ozonated water than by 0.5 mg/L ozonated water.

Conclusion: This study suggests that the salivary amylase and mucin decay ozone in a concentration-dependent manner, thereby attenuating the disinfection properties of ozonated water for SARS-CoV-2. An increase of the initial amount of ozone can ameliorate the disinfection effect of ozonated water on SARS-CoV-2. Ozone consumption should be taken into consideration for virus infection control. These results provide fundamental information about the effect of ozonated water when used to decontaminate surfaces harbouring SARS-CoV-2 in saliva.

Objectives: Our setting was challenged with an outbreak of different vancomycin resistant Enterococcus faecium (VREfm) including vanA and/or vanB containing isolates. Remarkably, it was observed that screening by use of a vanA and vanB real-time PCR on overnight enriched specimens from time to time tested positive for VanB with very low Ct-values, whereas VREfm-specific enrichment cultures remained negative. Here, we describe the analysis of the diagnostic results leading to adaptation of the diagnostic algorithm.

Methods: Per specimen of each patient, results of the vanA and vanB screening PCR and of the VREfm-specific culture (Brilliance VRE) were collected and combined with genotyping data of the identified VREfm isolates. During the outbreak, a second VREfm-specific culture medium (CHROMagar VRE) was introduced, and results were compared to the results obtained with Brilliance VRE agar.

Results: Thirty-five patients were identified as VREfm-carrier, in which four different strains were identified comprising vanA (STnew-CT7088) and/or vanB (ST80-CT1065, ST117-CT7117 and ST117-CT7118). Complementing results of PCR, culture and genotyping revealed that culture with Brilliance VRE agar was inadequate for detection of the vanB ST117 isolates identified, irrespective of vancomycin MIC values. In contrast, CHROMagar VRE was able to correctly detect these vanB ST117 isolates and other tested isolates.

Conclusions: Our data showed that the vanB ST117 containing isolates were inadequately detected by the VREfm-specific culture media, possibly contributing to unnoticed spread of VREfm. For this reason, CHROMagar VRE was evaluated during the outbreak and subsequently implemented in routine diagnostics, replacing Brilliance VRE agar.

Background: Hospital outbreaks caused by Mycobacteroides abscessus complex are a major cause for concern in vulnerable patients such as the cardiothoracic transplant population.

Aim: To describe the outbreak investigation and mitigation steps undertaken to address an increase in healthcare-associated Mycobacteroides abscessus (M. abscessus) complex cases in an inpatient cardiothoracic transplant population.

Methods: We extracted clinical characteristics from patients with M. abscessus pre-outbreak (March 2018 - December 2020) and during the outbreak (January 2021 - June 2022) from the electronic medical record. A multidisciplinary team conducted the outbreak investigation and devised a mitigation strategy to implement at our institution.

Findings: The baseline incidence of healthcare-associated M. abscessus was 0.11 cases per 10,000 patient-days; this increased to 0.24 cases per 10,000 patient-days during the outbreak. There were 1/9 (11%) cardiothoracic transplant patients in the pre-outbreak group compared to 7/12 (58%) during the outbreak, and respiratory specimen types compromised 6/9 (67%) of M. abscessus results in the pre-outbreak group compared to 10/12 (83%) during the outbreak. Among the clinical care activities involving water, a variety of water sources were utilized, including filtered and tap water. The incidence of healthcare-associated M. abscessus subsequently decreased to 0.06 cases per 10,000 patient-days after implementing an outbreak mitigation strategy of sterile water precautions.

Conclusion: Robust educational efforts from a multidisciplinary team on eliminating exposure to tap water were effective measures to reduce healthcare-associated M. abscessus incidence at our institution. NTM infection surveillance, targeted education, and water mitigation strategies may be beneficial preventative strategies for other lung transplant centres facing similar issues.

Background: Multi-resistant Gram-negative bacteria (GNB) survive in hospital drains in traps that contain water and may ascend into the sink because of splashes, or biofilm growth.

Aim: To investigate whether the 'Tuba Drain' (TD) a long, bent, continually descending copper tube between the sink outlet and the trap prevents the ascent of bacteria.

Methods: After initial laboratory tests confirmed that the TD prevented bacteria in the U-bend from splashing upwards into the sink outlet, TDs were assessed in a randomised, blinded trial in a hospital out-patients built in 2019. Sinks were paired into those with a similar clinical exposure and each member of each pair was randomised to receive either new, standard plumbing up to and including the trap (18 sinks) or the same new standard plumbing but including the TD inserted between the sink outlet and trap. Bacterial counts in swabs from the sink outlets were determined blindly before and monthly after the plumbing change for a year. GNBs that are associated with clinical infection and carriage of resistance genes, Pseudomonas aeruginosa, Acinetobacter baumanii, Stenotrophomonas maltophilia and all Enterobacteriales spp were the organisms of primary interest and termed target bacteria.

Findings: The TDs fitted into the required spaces and functioned without problems. The geometric means (over months) of the counts of target bacteria in TD-plumbed sinks was lower than those in their paired controls p= 0.012 (sign test 2 tailed). Prevalence of target bacteria in sinks was low.

Conclusion: TDs were effective for reducing target bacteria in sinks.