Candida auris can form long-lasting colonies in the hospital environment and on human skin. There is limited evidence regarding the efficacy of different methods and products for disinfecting hospitals and colonized patients to prevent the spread of C. auris. The minimum inhibitory concentration of three disinfectant products ("84" disinfectant, IodineTincture disinfectant, and quaternary ammonium) and 75% ethanol against C. auris and other Candida species were measured. A pig skin model was used to evaluate the efficacy of three hand hygiene products in killing pathogens. The killing effect of ultraviolet-C (253.7 nm) and the LK/CXD bed unit ozone disinfection machine on C. auris was also evaluated. Thirty seconds of pig skin washing with bacteriostatic hand sanitizer followed by drying and 15 s of ethanol-based gel can completely eradicate the colonization of C. auris (3.00 log10 CFU). The antifungal activity of ultraviolet-C to C. auris inoculated on bed sheets was significantly reduced (P < 0.01) at a distance of 1 m. Candida glabrata and C. auris showed greater resistance to ozone than other Candida species. The ozone could completely eradicate C. auris (3.60 log10 CFU) on bed sheets at dosage of 300 mg/m3 for 40 min of exposure. We recommend extending the disinfection times of ultraviolet-C and ozone and emphasizing the effectiveness of washing skin with soap, drying skin, and then applying an ethanol-based gel to remove C. auris from skin.

Background: Klebsiella pneumoniae(K. pneumoniae) is a common pathogen associated with hospital and community-onset infections. This study aimed to compare the clinical and microbiological characteristics of nosocomial, healthcare-associated (HCA), and community-acquired (CA)K. pneumoniaeinfections.Methods: Clinical data were extracted from electronic medical records and analyzed retrospectively. Antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) production were determined for all identified strains. Carbapenemase and ESBL genes were amplified by PCR. Genotyping of carbapenem-resistantK. pneumoniae(CRKP) and ESBL-producing strains was performed by pulsed-field gel electrophoresis (PFGE).Results: Of 379 K. pneumoniaeinfections, 98 (25.9%) were nosocomial, 195 (51.5%) were healthcare-associated, and 86 (22.6%) were community-acquired. Hematological malignancy (OR = 4.467), and hypertension (OR = 2.08) and cerebral vascular disease (OR = 2.486) were associated with nosocomial and HCA infections respectively, when compared to CA infections. Overall, the incidence of antimicrobial resistance for the majority of agents tested was similar between nosocomial and HCA infections (P > 0.05) and both groups had a higher incidence than CA infections (P < 0.05). Moreover, 95.1% (78/82) of CRKP strains were isolated from the nosocomial and HCA groups. Thebla_KPCwas the most prevalent carbapenemase gene among CRKP strains (80.5%, 66/82). ESBL-producing strains were prevalent among nosocomial (40.8%), HCA (35.9%) and CA groups (24.4%). Thebla_{CTX-M-9-group}andbla_{CTX-M-1-group}genes were predominant in nosocomial (65.0%) and CA strains (66.7%), respectively. PFGE results showed ESBL-producing and CRKP strains were genetically diverse. Identical PFGE profiles were observed among HCA and nosocomial strains.Conclusions: Nosocomial and HCAK. pneumoniaeinfections presented similar clinical features and antimicrobial resistance, and both two types of infections were different to CA infections. CRKP and ESBL-producing strains were disseminated mainly in HCA and nosocomial groups, and showed a clonal diversity. The cross transmission of CRKP was existed among HCA and nosocomial patients. This finding suggests that similar empirical therapy should be considered for patients with nosocomial and HCAK. pneumoniaeinfections and bacterial resistance surveillance of these infections is necessary.

Background: Acinetobacter baumannii (A. baumannii) is an widespread pathogen and carbapenem-resistant strains are great threat to hospitalized patients. This study is aimed to investigate the clinical characteristics, antimicrobial resistance patterns, and risk factors associated with carbapenem resistance in nosocomial, healthcare-associated (HCA), and community-acquired (CA) A. baumannii infections. Methods: This study retrospectively reviewed cases in a tertiary hospital in southern China between January 1, 2019, and December 31, 2021. Univariate and multivariate logistic regression analyses were performed to identified the risk factors of carbapenem resistance in nosocomial, HCA and CA A. baumannii infections. Results: A total of 391 patients with A. baumannii infection were included. Of these patients, 96 (24.6%) had nosocomial infections, 215 (55.0%) had HCA infections, and 80 (20.5%) had CA infections. The overall 30-day mortality rates of nosocomial and HCA infection patients was significantly higher than that of CA infection (P< 0.05). The incidence of antimicrobial resistance was also higher in nosocomial and HCA bacteremia than that in CA bacteremia (P< 0.05). Logistic regression analysis identified age ≥ 60 years, urethral catheterization, and exposure to two or more antibiotics as the independent risk factors for carbapenem-resistant A. baumannii (CRAB) infection in the nosocomial infection group and exposure to two or more antibiotics and endotracheal intubation in the HCA infection group. However, malignant tumors and hematological diseases were identified as protective factors against CRAB infection in the HCA group. Conclusion: These data suggest that HCA A. baumannii infection is quite different from CA infection, with antimicrobial resistance and 30-day mortality rates similar to those of nosocomial infections. Additionally, the risk factors for CRAB development in the CA, HCA, and nosocomial groups were not the same, which may provides the help for controlling practices and instruction empirical clinical medication.

The clustered regularly interspaced short palindromic repeats (CRISPR)‒CRISPR-associated protein (Cas) and restriction‒modification (R–M) systems are important immune systems in bacteria. Information about the distributions of these two systems in Klebsiella pneumoniae from different hosts and their mutual effect on antibiotic resistance and virulence is still limited. In this study, the whole genomes of 520 strains of K. pneumoniae from GenBank, including 325 from humans and 195 from animals, were collected for CRISPR‒Cas systems and type I R-M systems, virulence genes, antibiotic resistance genes, and multilocus sequence typing detection. The results showed that host origin had no obvious influence on the distributions of the two systems (CRISPR‒Cas systems in 29.8% and 24.1%, type I R-M systems in 9.8% and 11.8% of human-origin and animal-origin strains, respectively) in K. pneumoniae . Identical spacer sequences from different hosts demonstrated there was a risk of human–animal transmission. All virulence genes (yersiniabactin, colibactin, aerobactin, salmochelin, rmpADC , and rmpA2 ) detection rates were higher when only the CRISPR‒Cas systems were present but were all reduced when coexisting with type I R-M systems. However, a lower prevalence of most antibiotic-resistance genes was found when the CRISPR‒Cas systems were alone, and when type I R-M systems were coexisting, some of the antibiotic resistance gene incidence rates were even lower (quinolones, macrolides, tetracyclines and carbapenems), and some of them were higher instead (aminoglycosides, clindamycins, rifampicin-associated, sulfonamides, methotrexates, beta-lactamases and ultrabroad-spectrum beta-lactamases). The synergistic and opposed effects of the two systems on virulence and antibiotic-resistance genes need further study. IMPORTANCE: K. pneumoniae is an important opportunistic pathogen responsible for both human and animal infections, and the emergence of hypervirulent and multidrug-resistant K. pneumoniae has made it difficult to control this pathogen worldwide. Here, we find that CRISPR‒Cas and restriction–modification systems, which function as adaptive and innate immune systems in bacteria, have synergistic and opposed effects on virulence and antibiotic resistance genes in K. pneumoniae . Moreover, this study provides insights into the distributions of the two systems in K. pneumoniae from different hosts, and there is no significant difference in the prevalence of the two systems among K. pneumoniae spp. In addition, this study also characterizes the CRISPR arrays of K. pneumoniae from different hosts, suggesting that the strains sharing the same spacer sequences have the potential to spread between humans and animals.