The Impact of MRSA Colonization on Healthcare-Associated Infections in Long-Term Care Facility Residents: A Whole-Genome Sequencing-Based Study.

Methicillin-resistant Staphylococcus aureus (MRSA) colonization has been considered a risk factor for the development of infection, however, there are no studies that have compared the colonizing and infecting strains using whole-genome sequencing (WGS). The aim of this study is to determine the prevalence of and risk factors for MRSA colonization among long-term care facilities (LTCF) residents of Tenerife (Spain), and to analyze the epidemiological relationship between the colonizing and infecting strains using WGS. A point-prevalence study was carried out at 14 LTCFs in Tenerife from October 2020 to May 2021. Nasal swabs were cultured for MRSA. Colonized residents were followed up for two years. A phylogenetic comparison between colonization and infection strains was performed using WGS. A total of 764 residents were included. The prevalence of colonization by MRSA was 28.1% (n = 215), of which 12 (5.6%) subsequently developed infection. A close genetic relationship between colonization and infection isolates was found in three of the four (75%) residents studied. Our study confirms that colonized residents can develop serious MRSA infections from the same nasal colonization strain. Given the high prevalence of MRSA colonization in these centers, it is necessary to implement strategies with preventive measures to avoid the development of infection and the transmission of MRSA.

Identification and antibiogram of Enterobacterales from direct urine samples using matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) technology and disk-plate diffusion technique.

Identification and antibiogram of uropathogenic microorganisms from direct urine samples present a great clinical impact. Here, we present a combined procedure to determine identification (IDd) of bacteria through MALDI-TOF-MS technology and antibiogram (ATBd) using disk-plate diffusion technique, of UTI-producing Enterobacterales against the most used antibiotics. Ninety-four urine samples with presence of pyuria and Gram-negative bacilli were selected. The IDd showed a high success rate (90%). ATBd procedure showed a high correlation for tested antibiotics. This simplified, low cost and reduced work time two-step procedure significantly reduces results turnaround time and benefit the clinical management of patients with UTI.

Risk factors for colonization by carbapenemase-producing bacteria in Spanish long-term care facilities: a multicentre point-prevalence study.

BACKGROUND: The emergence of carbapenemase-producing bacteria (CPB) has become a major public health concern. Long-term care facilities (LTCF) are potential reservoirs for multidrug-resistant micro-organisms (MDRO). However, data on CPB is limited. The study aims to determine the prevalence of MDRO and risk factors for CPB colonization among residents of LTCFs. METHODS: A point-prevalence study was conducted at 14 LTCFs in Tenerife (Spain) between October 2020 and May 2021. Nasal and rectal swabs were cultured for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), carbapenemase-producing Enterobacterales, MDR Acinetobacter baumannii (MDR-Ab) and MDR Pseudomonas aeruginosa. Antimicrobial susceptibility testing and molecular detection of resistance genes were performed. Risk factors for colonization by carbapenemase-producing bacteria (CPB) were determined by univariate and multivariate analysis. RESULTS: A total of 760 LTCF residents were recruited. The prevalence of colonization by CPB was 9.3% (n = 71) with the following distribution: 35 (49.3%) K. pneumoniae, 26 (36.6%) MDR-Ab, 17 (23.9%) E. coli, and 1 (1.4%) C. koseri. In addition, the prevalence of colonization by MRSA was 28.1% (n = 215) and only one case of VRE was isolated. Multivariate analysis identified male sex (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.86-3.11; P = 0.01), having a high health requirement (OR, 6.32; 95% CI, 1.91-20.92; P = 0.003) and previous hospitalization (OR, 3.60; 95% CI, 1.59-8.15 P = 0.002) as independent risk factors for CPB rectal carriage. CONCLUSIONS: LTCFs are an important reservoir for MDRO, including CPB. We have identified some predictors of colonization by CPB, which enable a more targeted management of high-risk residents. Antimicrobial stewardship programmes and infection control preventive measures are needed to stop acquisition and transmission of MDRO.