Journal of Hospital Infection最新文献

Objective: To report the epidemiological, diagnostic, and genetic investigation of an outbreak of neonatal patients infected or colonized with Serratia marcescens (S. marcescens) including the infection control interventions.

Design: Outbreak investigation report.

Setting: 28-bedded neonatal unit in an acute care tertiary hospital in Singapore divided into three areas: two negative-pressure airborne infection isolation rooms with a shared anteroom, 10 neonatal intensive care unit (NICU) beds, and 16 high dependency beds.

Patients: A total of five neonates were involved in this outbreak.

Methods: Screening of in-flight patients and their immediate environment for S. marcescens to determine probable environmental sources, whole genome sequencing (WGS) analysis of resulting isolates to determine clone-relatedness and possible transmission patterns. Implementation of infection control interventions included prompt isolation of cases, enhanced equipment and environmental disinfection, use of alcohol-based hand rub as the preferred hand hygiene mode, enhanced infection prevention orientation for parents, review of practices, audits, and immediate feedback on non-compliance.

Results: Five neonates infected or colonized with S. marcescens were involved in this outbreak. Four were infection cases whilst one identified through contact tracing. Three NICU sinks and the milk preparation room sink were tested positive for S. marcescens. WGS confirmed clonality of strains from two NICU sinks, and milk preparation room sink with that of the five neonates.

Conclusion: Multiprong strategy was required to contain this outbreak. WGS analysis showed association of biofilms in sinks with the outbreak.

Core genome single-nucleotide polymorphism phylogeny was used to characterise a nosocomial outbreak caused by ST-80 Vancomycin-resistant Enterococcus faecium (VREf). It identified 22 of 25 epidemiologically related isolates as belonging to an outbreak cluster. The use of Fourier-transform infrared (FT-IR) spectroscopy with a cluster-defining cut-off of 0.071 resulted in the correct classification of 21 of 22 phylogenetically related isolates in a single cluster. It successfully distinguished three phylogenetically unrelated isolates from the outbreak cluster, along with five ST-80 unrelated control isolates, and five isolates from a previous outbreak in May 2023, yielding only one mischaracterised environmental isolate. These findings support the potential use of FT-IR spectroscopy as a rapid screening tool to assist outbreak investigations. Notably, this study is the first to focus on the performance of FT-IR spectroscopy in the epidemiological analysis of VREf isolates with the same sequence type.

Background: This study aimed to summarize the characteristics of laboratory-acquired infections (LAIs) and review exposure incidents in clinical laboratories. Additionally, a meta-analysis was conducted to estimate post-exposure incidence rates and evaluate the efficacy of post-exposure prophylaxis (PEP) following Brucella exposures.

Methods: A systematic search across databases including PubMed, Embase, Web of Science, CNKI, Wanfang, CMB, and the ABSA LAI database was conducted to extract relevant literature published during January 1, 1990, to August 31, 2023. Case reports and laboratory exposure risk events in clinical laboratories were included. Negative-binomial regression was used to estimate the relative increase in reported numbers per year of LAIs. A meta-analysis was performed to estimate the incidence rate (IR) of LAIs among exposed laboratory personnel after Brucella exposure risk events.

Findings: A total of 164 LAIs were reported in hospital laboratories. Negative-binomial regression analysis indicated no significant decline in annual LAIs reports (relative risk and 95% CI: 0.9834 [0.9667,1.0001], P value: 0.052). Most LAIs (68.3%) occurred during routine work, with only 9.8% linked to laboratory unintended exposure. The leading pathogens were Brucella (55.5%), Neisseria meningitidis (7.3%), and Shigella sonnei (5.5%). The proportion of LAIs caused by Brucella in developing countries was higher than that in developed countries (72.4% vs. 48.7%). The meta-analysis revealed that the incidence rate for Brucella-related LAIs among laboratory personnel was calculated to be 60 per 100,000 laboratory personnel. Laboratory personnel exposed to high-risk Brucella incidents faced a notably elevated infection risk, estimated at 80 per 100,000 laboratory personnel. Among higher-risk Brucella exposures, laboratory personnel who did not receive PEP experienced a 6.33 times higher risk of infection compared to those who did. The attributable fraction associated with the absence of PEP was 84.2%.

Conclusions: Clinical laboratory personnel remain at infection risk, with no reduction in reported LAI cases, mainly resulting from Brucella acquisitions. PEP proved effective against high-risk Brucella exposures.

Objectives: Candida tropicalis is a medically important yeast with rising antifungal resistance, while nosocomial transmission is rarely reported. Here we genotyped C. tropicalis isolates from Italian hospitals to uncover potential nosocomial transmission and assess resistance.

Methods: A total of 197 C. tropicalis isolates from 161 patients was collected from five centres from 2013 to 2023. Short tandem repeat (STR) genotyping was conducted on all isolates and a selection of 24 isolates was typed with whole genome sequencing (WGS) and the novel Fourier-transform infrared (FTIR) spectroscopy method. Antifungal resistance was investigated with microbroth dilution and WGS.

Results: STR genotyping revealed seven clusters with isolates from multiple patients. WGS single nucleotide polymorphism (SNP) analysis on five groups of isolates with related STR genotypes also separated these isolates into five groups, of which two groups contained a cluster of isolates from different patients distinguished by 59 or fewer SNPs. In comparison, sequential isolates within three patients were differentiated by 141 SNPs at most. The two C. tropicalis WGS clusters also clustered based on FTIR genotyping, although this method did not separate the isolates into five groups. None of the 24 isolates were resistant to common antifungals.

Conclusions: WGS SNP analysis indicated nosocomial transmission of two lineages within the same hospital, highlighting the need for enforced infection prevention measures and the need for routine genotyping on this common yeast in clinical settings. While both STR and FTIR genotyping also clustered these lineages, WGS SNP analysis is required to determine whether isolates were clonally transmitted.

The cleaning of reusable medical devices involves inherent challenges that can impact on the effectiveness of the cleaning process; consequently, the subsequent safety of patients. Fluid dynamics play a critical role in determining the flow and distribution of cleaning agents where the design of the device can either facilitate or hinder this important process. Complex geometries, narrow channels, or irregular surfaces can impede effective flushing of contaminants leading to incomplete cleaning that creates a greater likelihood for patient contamination risks. Device features (n =23) were exposed to the most challenging cleaning conditions to find the point of failure in both fluid dynamics and soil retention. Experimental results obtained from the aforementioned along with associated compound risks were used to assign a risk value. Using the "hardest to clean" device feature approach as the base risk value, the total quantitative risk score was calculated for different reusable medical devices from numerical values obtained from addressing 14 questions focusing on variability in geometry, material use, types of cleaning, and intended patient use. Patient risk values for devices with different features were calculated from using Kremer's cleaning categories based on position within value ranges. Occurrences less than 18 correspond to minimal risk devices while a total risk score between the values of 18-39 are moderate and equal to or above 40 scores corresponds to the maximal category. Application of this quantitative assessment approach will facilitate appropriate mitigation of risk for cleaning reusable medical devices by informing use of targeted effective interventions. Future use of this Kremer cleaning classification will complement and augment disinfection and sterilization modalities.

Background: Proper hand hygiene is extremely important to control the transmission of pathogens. Although many studies have been undertaken on the effect of washing and drying on bacterial contamination of hands, studies on viral contamination are scarce.

Aim: To assess the viral load of artificially contaminated hands after washing and after drying.

Methods: Thirty volunteers completed a questionnaire on hand hygiene, and participated in microbial assays testing five different drying approaches, using whole-hand methodology, to quantify viruses on hands. Bacterial assays were also performed for comparison purposes.

Results: For both viruses and bacteria, the washing step promoted a significant reduction in the microbial load, while the drying step only promoted a slight reduction, regardless of the drying method used. Hand dryers and paper towels did not induce recontamination of washed hands.

Conclusions: Handwashing promoted a reduction in the microbial load of hands, but none of the drying methods tested led to a significant reduction in the microbial load of hands.