Colonization by Extended-Spectrum ß-Lactamase-Producing Enterobacterales and Bacteremia in Hematopoietic Stem Cell Transplant Recipients.

BACKGROUND: Assessing the risk of multidrug-resistant colonization and infections is pivotal for optimizing empirical therapy in hematopoietic stem cell transplants (HSCTs). Limited data exist on extended-spectrum ß-lactamase-producing Enterobacterales (ESBL-E) colonization in this population. This study aimed to assess whether ESBL-E colonization constitutes a risk factor for ESBL-E bloodstream infection (BSI) and to evaluate ESBL-E colonization in HSCT recipients. METHODS: A retrospective analysis of ESBL-E colonization and BSI in HSCT patients was conducted from August 2019 to June 2022. Weekly swabs were collected and cultured on chromogenic selective media, with PCR identifying the ß-lactamase genes. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) assessed the colonizing strains' similarities. RESULTS: Of 222 evaluated HSCT patients, 59.45% were colonized by ESBL-E, with 48.4% at admission. The predominant ß-lactamase genes were blaTEM (52%) and blaSHV (20%). PFGE analysis did not reveal predominant clusters in 26 E. coli and 15 K. pneumoniae strains. WGS identified ST16 and ST11 as the predominant sequence types among K. pneumoniae. Thirty-three patients developed thirty-five Enterobacterales-BSIs, with nine being third-generation cephalosporin-resistant. No association was found between ESBL-E colonization and ESBL-BSI (p = 0.087). CONCLUSIONS: Although the patients presented a high colonization rate of ESBL-E upon admission, no association between colonization and infection were found. Thus, it seems that ESBL screening is not a useful strategy to assess risk factors and guide therapy for ESBL-BSI in HSCT-patients.

COVID-19 in hematopoietic stem cell transplant recipients during three years of the pandemic: a multicenter study in Brazil.

Hematopoietic stem cell transplant (HSCT) recipients are at -increased risk for severe COVID-19. The aim of this study was to evaluate the burden of COVID-19 in a cohort of HSCT recipients. This retrospective study evaluated a cohort of adult hospitalized HSCT recipients diagnosed with COVID-19 in two large hospitals in São Paulo, Brazil post-HSCT, from January 2020 to June 2022. The primary outcome was all-cause mortality. Of 49 cases, 63.2% were male with a median age of 47 years. Allogeneic-HSCT (51.2%) and autologous-HSCT (48.9%) patients were included. The median time from HSCT to COVID-19 diagnosis was 398 days (IQR: 1211-134), with 22 (44.8%) cases occurring within 12 months of transplantation. Most cases occurred during the first year of the pandemic, in non-vaccinated patients (n=35; 71.4%). Most patients developed severe (24.4%) or critical (40.8%) disease; 67.3% received some medication for COVID-19, primarily corticosteroids (53.0%). The probable invasive aspergillosis prevalence was 10.2%. All-cause mortality was 40.8%, 51.4% in non-vaccinated patients and 14.2% in patients who received at least one dose of the vaccine. In the multiple regression analyses, the variables mechanical ventilation (OR: 101.01; 95% CI: 8.205 - 1,242.93; p = 0.003) and chest CT involvement at diagnosis ≥50% (OR: 26.61; 95% CI: 1.06 - 664.26; p = 0.04) remained associated with all-cause mortality. Thus, HSCT recipients with COVID-19 experienced high mortality, highlighting the need for full vaccination and infection prevention measures.

COVID-19 in hematopoietic stem cell transplant recipients during three years of the pandemic: a multicenter study in Brazil

ABSTRACT Hematopoietic stem cell transplant (HSCT) recipients are at -increased risk for severe COVID-19. The aim of this study was to evaluate the burden of COVID-19 in a cohort of HSCT recipients. This retrospective study evaluated a cohort of adult hospitalized HSCT recipients diagnosed with COVID-19 in two large hospitals in São Paulo, Brazil post-HSCT, from January 2020 to June 2022. The primary outcome was all-cause mortality. Of 49 cases, 63.2% were male with a median age of 47 years. Allogeneic-HSCT (51.2%) and autologous-HSCT (48.9%) patients were included. The median time from HSCT to COVID-19 diagnosis was 398 days (IQR: 1211-134), with 22 (44.8%) cases occurring within 12 months of transplantation. Most cases occurred during the first year of the pandemic, in non-vaccinated patients (n=35; 71.4%). Most patients developed severe (24.4%) or critical (40.8%) disease; 67.3% received some medication for COVID-19, primarily corticosteroids (53.0%). The probable invasive aspergillosis prevalence was 10.2%. All-cause mortality was 40.8%, 51.4% in non-vaccinated patients and 14.2% in patients who received at least one dose of the vaccine. In the multiple regression analyses, the variables mechanical ventilation (OR: 101.01; 95% CI: 8.205 - 1,242.93; p = 0.003) and chest CT involvement at diagnosis ≥50% (OR: 26.61; 95% CI: 1.06 - 664.26; p = 0.04) remained associated with all-cause mortality. Thus, HSCT recipients with COVID-19 experienced high mortality, highlighting the need for full vaccination and infection prevention measures.

Case Report: In Situ and Systemic Immune Response to Mucosal Leishmaniasis in an HIV-Infected Patient.

In situ and systemic evaluations of the immune responses of HIV-infected patients to mucosal leishmaniasis have been poorly described. We describe a recently diagnosed HIV-infected patient with mucosal leishmaniasis who was characterized by a CD4 count of 85 cells/mm3 and nasal septum destruction resulting from pruritic and ulcerated nasal mucosa with crust formation and progression over 2 years. In situ and systemic immune evaluations of T cell activation, memory, and exhaustion were conducted using cytofluorometric assays, and sequencing of the Leishmania species was performed. The immune profile of HIV-infected patient with mucosal leishmaniasis shows a mixed Th1/Th2 pattern and an activated and exhausted status.

Epidemiologic case investigation on the zoonotic transmission of Methicillin-resistant Staphylococcus pseudintermedius among dogs and their owners.

Dogs often carry methicillin-resistant Staphylococci asymptomatically. These bacteria are frequently linked to conditions such as canine pyoderma and otitis. Close interaction between dogs and humans can facilitate the exchange of resistant strains, particularly Methicillin-resistant Staphylococcus pseudintermedius (MRSP). This represents a public health issue, since these strains, in addition to occasionally causing infections in humans, can also serve as a source of resistance and virulence genes for strains of greater importance in human medicine, such as Staphylococcus aureus. Furthermore, MRSP strains are often multidrug resistant, which ends up compromising the treatment of infections. This study aimed to assess the potential transmission of Staphylococcus pseudintermedius among dogs and their owners. We examined a total of one hundred canine samples collected from cases of pyoderma and otitis to detect the presence of staphylococci. Simultaneously, we conducted evaluations on all dog owners. Staphylococci strains were identified using MALDI-TOF MS and PCR targeting the nuc gene. Methicillin resistance screening was also performed by detecting the mecA gene using PCR. Among the sampled dogs, 64 carried S. pseudintermedius. Nine were identified as MRSP. In six instances, dogs and their owners exhibited S. pseudintermedius. These samples underwent genome sequencing and were screened for antimicrobial resistance genes, SCCmec typing, MLST characterization, and Single Nucleotide Polymorphisms (SNP) analyses. The results of the phylogenetic analysis revealed that in three cases, dogs and owners had closely related isolates, suggesting interspecies transmission. Two of these cases involved MRSP and one MSSP. Moreover, in the two MRSP cases, the same SCCmec type (type V) was detected. Additionally, the sequence type was consistent across all three cases involving dogs and owners (MSSP ST2277, MRSP ST2282, and ST2286). These findings strongly indicate a transmission event. Since Staphylococcus pseudintermedius is primarily isolated from canine samples, it is plausible that dogs may have acted as a potential source. In the remaining three cases, despite identifying the same species in both samples, they had notable phylogenetic differences.

Clinical markers of post-Chikungunya chronic inflammatory joint disease: A Brazilian cohort.

BACKGROUND: Chikungunya-fever (CHIKF) remains a public health major issue. It is clinically divided into three phases: acute, post-acute and chronic. Chronic cases correspond to 25-40% individuals and, though most of them are characterized by long-lasting arthralgia alone, many of them exhibit persistent or recurrent inflammatory signs that define post-Chikungunya chronic inflammatory joint disease (pCHIKV-CIJD). We aimed to identify early clinical markers of evolution to pCHIKV-CIJD during acute and post-acute phases. METHODOLOGY/PRINCIPAL FINDINGS: We studied a prospective cohort of CHIKF-confirmed volunteers with longitudinal clinical data collection from symptoms onset up to 90 days, including a 21-day visit (D21). Of 169 patients with CHIKF, 86 (50.9%) completed the follow-up, from whom 39 met clinical criteria for pCHIKV-CIJD (45.3%). The relative risk of chronification was higher in women compared to men (RR = 1.52; 95% CI = 1.15-1.99; FDR = 0.03). None of the symptoms or signs presented at D0 behaved as an early predictor of pCHIKV-CIJD, while being symptomatic at D21 was a risk factor for chronification (RR = 1.31; 95% CI = 1.09-1.55; FDR = 0.03). Significance was also observed for joint pain (RR = 1.35; 95% CI = 1.12-1.61; FDR = 0.02), reported edema (RR = 3.61; 95% CI = 1.44-9.06; FDR = 0.03), reported hand and/or feet small joints edema (RR = 4.22; 95% CI = 1.51-11.78; FDR = 0.02), and peri-articular edema observed during physical examination (RR = 2.89; 95% CI = 1.58-5.28; FDR = 0.002). Furthermore, patients with no findings in physical examination at D21 were at lower risk of chronic evolution (RR = 0.41, 95% CI = 0.24-0.70, FDR = 0.01). Twenty-nine pCHIKV-CIJD patients had abnormal articular ultrasonography (90.6% of the examined). The most common findings were synovitis (65.5%) and joint effusion (58.6%). CONCLUSION: This cohort has provided important insights into the prognostic evaluation of CHIKF. Symptomatic sub-acute disease is a relevant predictor of evolution to chronic arthritis with synovitis, drawing attention to joint pain, edema, multiple articular involvement including small hand and feet joints as risk factors for chronification beyond three months, especially in women. Future studies are needed to accomplish the identification of accurate and early biomarkers of poor clinical prognosis, which would allow better understanding of the disease's evolution and improve patients' management, modifying CHIKF burden on global public health.

Virulomic Analysis of Multidrug-Resistant Klebsiella pneumoniae Isolates and Experimental Virulence Model Using Danio rerio (Zebrafish).

This study evaluates a possible correlation between multidrug-resistant Klebsiella pneumoniae strains and virulence markers in a Danio rerio (zebrafish) model. Whole-genome sequencing (WGS) was performed on 46 strains from three Brazilian hospitals. All of the isolates were colistin-resistant and harbored blaKPC-2. Ten different sequence types (STs) were found; 63% belonged to CC258, 22% to ST340, and 11% to ST16. The virulence factors most frequently found were type 3 fimbriae, siderophores, capsule regulators, and RND efflux-pumps. Six strains were selected for a time-kill experiment in zebrafish embryos: infection by ST16 was associated with a significantly higher mortality rate when compared to non-ST16 strains (52% vs. 29%, p = 0.002). Among the STs, the distribution of virulence factors did not differ significantly except for ST23, which harbored a greater variety of factors than other STs but was not related to a higher mortality rate in zebrafish. Although several virulence factors are described in K. pneumoniae, our study found ST16 to be the only significant predictor of a virulent phenotype in an animal model. Further research is needed to fully understand the correlation between virulence and sequence types.

Characterization of Severe Acute Respiratory Syndrome Coronavirus 2 Omicron Variant Shedding and Predictors of Viral Culture Positivity on Vaccinated Healthcare Workers With Mild Coronavirus Disease 2019.

In this prospective cohort of 30 vaccinated healthcare workers with mild Omicron variant infection, we evaluated viral culture, rapid antigen test (RAT), and real-time reverse-transcription polymerase chain reaction (RT-PCR) of respiratory samples at days 5, 7, 10, and 14. Viral culture was positive in 46% (11/24) and 20% (6/30) of samples at days 5 and 7, respectively. RAT and RT-PCR (Ct ≤35) showed 100% negative predictive value (NPV), with positive predictive values (PPVs) of 32% and 17%, respectively, for predicting viral culture positivity. A lower RT-PCR threshold (Ct ≤24) improved culture prediction (PPV = 39%; NPV = 100%). Vaccinated persons with mild Omicron infection are potentially transmissible up to day 7. RAT and RT-PCR might be useful tools for shortening the isolation period.

Persistence of a multidrug-resistant worldwide-disseminated methicillin-resistant Staphylococcus epidermidis clone harbouring the cfr linezolid resistance gene in a French hospital with evidence of interspecies transfer to several Staphylococcus aureus lineages.

BACKGROUND: Resistance to linezolid has become a worldwide concern since it is one of the last-resort antibiotics to treat multidrug-resistant staphylococcal and enterococcal infections. OBJECTIVES: We investigated staphylococcal infections caused by 16 cfr-positive linezolid-resistant Staphylococcus epidermidis and Staphylococcus aureus isolates in a French university hospital from 2015 to 2018. METHODS: Antimicrobial susceptibility of isolates was tested by broth microdilution and gradient strips. Genetic determinants of linezolid resistance (including cfr gene and 23S rRNA mutations) were assessed by PCR and WGS; the latter was also used to characterize the cfr-carrying plasmids in S. epidermidis and S. aureus, and to explore the clonal relationship of isolates. RESULTS: All linezolid-resistant staphylococcal isolates harboured the same cfr-carrying plasmid, sharing 99% identity with the previously described pSA737. The three S. aureus isolates belonged to different STs (ST8, ST72, ST2416); the 13 methicillin-resistant S. epidermidis (MRSE) belonged to ST2 and harboured both cfr and mutations in genes encoding 23S rRNA and ribosomal proteins. Phylogenetic analysis grouped the MRSE isolates into two clusters, one of which (n = 12 isolates) belonged to the recently reported multidrug-resistant worldwide-disseminated S. epidermidis lineages. CONCLUSIONS: The results presented herein highlight the persistence and efficient spread of a cfr-carrying plasmid in a hospital related both to the dissemination of a multidrug-resistant S. epidermidis clone and the in vivo interspecies transfer of cfr between S. epidermidis and S. aureus. The emergence of linezolid-resistant strains should be closely monitored, and the mechanisms involved systematically explored in order to limit the spread of plasmid-mediated resistance.

Impact of the COVID-19 pandemic on the incidence of multidrug-resistant bacterial infections in an acute care hospital in Brazil.

BACKGROUND: The impact of COVID-19 on healthcare- associated infections (HCAI) caused by multidrug-resistant (MDR) bacteria that contribute to higher mortality is a growing area of study METHODS: This retrospective observational study compares the incidence density (ID) of HCAI caused by MDR bacteria (CRE, CRAB, CRP, MRSA and VRE) pre-COVID (2017-2019) and during the COVID-19 pandemic (2020) in overall hospitalized patients and in intensive care (ICU) units. RESULTS: We identified 8,869 HCAI, of which 2,641 (29.7%) were caused by bacterial MDR, and 1,257 (14.1%) were from ICUs. The overall ID of MDR infections increased 23% (P < .005) during COVID-19. The overall per-pathogen analysis shows significant increases in infections by CRAB and MRSA (+108.1%, p<0.005; +94.7%, p<0.005, respectively), but not in CRE, CRP, or VRE. In the ICU, the overall ID of MDR infections decreased during COVID, but that decline was not significant (-6.5%, P = .26). The ICU per-pathogen analysis of ID of infection showed significant increases in CRAB and MRSA (+42.0%, P = .001; +46.2%, P = .04), significant decreases in CRE and CRP (-26.4%, P = .002; -44.2%, P = 0.003, respectively) and no change in VRE. CONCLUSIONS: The COVID-19 pandemic correlates to an increase in ID of CRAB and MRSA both in ICU and non-ICU setting, and a decrease in ID of CRE and CRP in the ICU setting. Infection control teams should be aware of possible outbreaks of CRAB and MRSA and promote rigorous adherence to infection control measures as practices change to accommodate changes in healthcare needs during and after the pandemic.

Phenotypic and genotypic characteristics of a carbapenem-resistant Serratia marcescens cohort and outbreak: describing an opportunistic pathogen.

Serratia marcescens is an emerging opportunistic pathogen with high genetic diversity. This article describes the microbiological characteristics of isolates and the risk factors for infections caused by carbapenem-resistant S. marcescens. A retrospective study of patients colonized (n=43) and infected (n=20) with carbapenem-resistant S. marcescens over a 3-year period was conducted. Polymerase chain reaction for carbapenemase genes and molecular typing of all available strains was performed. Forty-two isolates were analysed, including three environmental samples identified during an outbreak. Thirty-five carbapenem-resistant S. marcescens carried blaKPC-2, one isolate was blaNDM-positive and four isolates carried blaOXA-101. The genomes were grouped into three clusters with 100% bootstrap; three patterns of mutations on ompC and ompF were found. The strains carried virulence genes related to invasion and haemolysis, and the environmental strains presented fewer mutations on the virulence genes than the clinical strains. Multi-variate analysis showed that previous use of polymyxin (P=0.008) was an independent risk factor for carbapenem-resistant S. marcescens infection. This study highlighted that blaKPC-2 in association with ompC or ompF mutation was the most common mechanism of resistance in the study hospital, and that previous use of polymyxin was an independent risk factor for carbapenem-resistant S. marcescens. There was a predominant clone, including the environmental isolates, suggesting that cross-transmission was involved in the dissemination of this pathogen.

Genetic description of VanD phenotype vanA genotype in vancomycin-resistant Enterococcus faecium isolates from a Bone Marrow Transplantation Unit.

BACKGROUND: Vancomycin-resistant Enterococcus faecium (VREfm) is an important agent of hospital-acquired infection. VanA phenotype is characterized by resistance to high levels of vancomycin and teicoplanin and is encoded by the vanA gene, whereas VanD phenotype is characterized by resistance to vancomycin and susceptibility or intermediate resistance to teicoplanin; however, some isolates carry a VanD phenotype with a vanA genotype, but there are many gaps in the knowledge about the genetic mechanisms behind this pattern. OBJECTIVE: To characterize the genetic structure, clonality, and mobile genetic elements of VRE isolates that display a VanD-vanA phenotype. RESULTS: All vanA VRE-fm isolates displayed minimum inhibitory concentration (MIC) for vancomycin > 32µg/mL and intermediate or susceptible MIC range for teicoplanin (8-16µg/mL). The isolates were not clonal, and whole-genome sequencing analysis showed that they belonged to five different STs (ST478, ST412, ST792, ST896, and ST1393). The absence of some van complex genes were observed in three isolates: Ef5 lacked vanY and vanZ, Ef2 lacked vanY, and Ef9 lacked orf1 and orf2; moreover, another three isolates had inverted positions of orf1, orf2, vanR, and vanS genes. IS1542 was observed in all isolates, whereas IS1216 in only five. Moreover, presence of other hypothetical protein-encoding genes located downstream the vanZ gene were observed in six isolates. CONCLUSION: VRE isolates can display some phenotypes associated to vanA genotype, including VanA and VanB, as well as VanD; however, further studies are needed to understand the exact role of genetic variability, rearrangement of the transposon Tn1546, and presence of insertion elements in isolates with this profile.

Are mobile phones part of the chain of transmission of SARS-CoV-2 in hospital settings?

Mobile phones (MPs) have become an important work tool around the world including in hospitals. We evaluated whether SARS-CoV-2 can remain on the surface of MPs of first-line healthcare workers (HCW) and also the knowledge of HCWs about SARS-CoV-2 cross-transmission and conceptions on the virus survival on the MPs of HCWs. A cross-sectional study was conducted in the COVID-19 Intensive Care Unit of a teaching hospital. An educational campaign was carried out on cross-transmission of SARS-CoV-2, and its permanence in fomites, in addition to the proper use and disinfection of MPs. Herewith an electronic questionnaire was applied including queried conceptions about hand hygiene and care with MP before and after the pandemic. The MPs were swabbed with a nylon FLOQ Swab™, in an attempt to increase the recovery of SARS-CoV-2. All MP swab samples were subjected to SARS-CoV-2 RT-PCR; RT-PCR positive samples were subjected to viral culture in Vero cells (ATCC® CCL-81™). Fifty-one MPs were swabbed and a questionnaire on hand hygiene and the use and disinfection of MP was applied after an educational campaign. Most HCWs increased adherence to hand hygiene and MP disinfection during the pandemic. Fifty-one MP swabs were collected and two were positive by RT-PCR (4%), with Cycle threshold (Ct ) values of 34-36, however, the cultures of these samples were negative. Although most HCWs believed in the importance of cross-transmission and increased adherence to hand hygiene and disinfection of MP during the pandemic, SARS-CoV-2 RNA was detected in MPs. Our results suggest the need for a universal policy in infection control guidelines on how to care for electronic devices in hospital settings.

Procalcitonin as a biomarker for ventilator associated pneumonia in COVID-19 patients: Is it an useful stewardship tool?

Ventilator associated pneumonia(VAP) is a severe complication that can lead to high mortality when not early identified or when therapy is delayed. The aim of this study was to evaluate procalcitonin(PCT) as a biomarker for VAP development. In total, 73 hospitalized patients with COVID-19 were analyzed. PCT levels greater than 0.975ng/mL were more related to VAP. No association was found for C-reactive protein (CRP). The results show that procalcitonin may be a pertinent biomarker for VAP diagnosis and can be a helpful tool for antibiotic withdrawal.

Evaluation of loop-mediated isothermal amplification assay for detection of Clostridioides difficile infection: A prospective diagnostic performance study.

A novel Loop-mediated isothermal amplification (LAMP) assay, HiberGene's CD was evaluated with 82 unformed stools from patients suspected of C. difficile infection (CDI). Compared to glutamate dehydrogenase (GDH) toxins A/B test (C.diff Quik Chek®), HiberGene's LAMP showed 100% of sensitivity and 95,8% of specificity; and compared to FilmArray™ GI panel ® (BioFire), a sensitivity of 81,2% and a specificity of 100%, with 96.38% of agreement.

Colistin-resistant Escherichia coli belonging to different sequence types: genetic characterization of isolates responsible for colonization, community- and healthcare-acquired infections.

The plasmid-mediated colistin-resistance gene named mcr-1 has been recently described in different countries and it became a public health challenge. Of note, few studies have addressed the spread of Escherichia coli harboring the mcr-1 gene in both, community and hospital settings. A total of seven colistin-resistant E. coli carrying mcr-1, collected from 2016 to 2018, from community (n=4), healthcare-acquired infections (n=2) and colonization (n=1) were identified in three high complexity hospitals in Sao Paulo, Brazil. These colistin-resistant isolates were screened for mcr genes by PCR and all strains were submitted to Whole Genome Sequencing and the conjugation experiment. The seven strains belonged to seven distinct sequence types (ST744, ST131, ST69, ST48, ST354, ST57, ST10), and they differ regarding the resistance profiles. Transference of mcr-1 by conjugation to E. coli strain C600 was possible in five of the seven isolates. The mcr-1 gene was found in plasmid types IncX4 or IncI2. Three of the isolates have ESBL-encoding genes (blaCTX-M-2, n=2; blaCTX-M-8, n=1). We hereby report genetically distinct E. coli isolates, belonging to seven STs, harboring the mcr-1 gene, associated to community and healthcare-acquired infections, and colonization in patients from three hospitals in Sao Paulo. These findings point out for the potential spread of plasmid-mediated colistin-resistance mechanism in E. coli strains in Brazil.

Reductive evolution of virulence repertoire to drive the divergence between community- and hospital-associated methicillin-resistant Staphylococcus aureus of the ST1 lineage.

Methicillin-resistant Staphylococcus aureus (MRSA) of the ST1-SCCmecIV lineage has been associated with community-acquired (CA) infections in North America and Australia. In Brazil, multi-drug resistant ST1-SCCmecIV MRSA has emerged in hospital-associated (HA) diseases in Rio de Janeiro. To understand these epidemiological differences, genomic and phylogenetic analyses were performed. In addition, virulence assays were done for representative CA - and HA-MRSA strains. Despite the conservation of the virulence repertoire, some genes were missing in Brazilian ST1-SCCmecIV including lukSF-PV, fnbB, and several superantigen-encoded genes. Additionally, CA-MRSA lost the splDE while HA-MRSA strains conserved the complete operon. Most of these variable genes were located in mobile genetic elements (MGE). However, conservation and maintenance of MGEs were often observed despite the absence of their associated virulence markers. A Bayesian phylogenetic tree revealed the occurrence of more than one entrance of ST1 strains in Rio de Janeiro. The tree shape and chronology allowed us to infer that the hospital-associated ST1-SCCmecIV from Brazil and the community-acquired USA400 from North America are not closely related and that they might have originated from different MSSA strains that independently acquired SCCmecIV cassettes. As expected, representatives of ST1 strains from Brazil showed lower cytotoxicity and a greater ability to survive inside human host cells. We suggest that Brazilian ST1-SCCmecIV strains have adapted to the hospital setting by reducing virulence and gaining the ability to persist and survive inside host cells. Possibly, these evolutionary strategies may balance the biologic cost of retaining multiple antibiotic resistance genes.

Decontamination and re-use of surgical masks and respirators during the COVID-19 pandemic.

OBJECTIVES: The coronavirus disease 2019 pandemic increased global demand for personal protective equipment (PPE) and resulted in shortages. The study evaluated the re-use of surgical masks and respirators by analysing their performance and safety before and after reprocessing using the following methods: oven, thermal drying, autoclave, and hydrogen peroxide plasma vapour. METHODS: In total, 45 surgical masks and 69 respirators were decontaminated. Visual integrity, air permeability, burst resistance, pressure differential and particulate filtration efficiency of new and decontaminated surgical masks and respirators were evaluated. In addition, 14 used respirators were analysed after work shifts before and after decontamination using reverse transcription polymerase chain reaction (RT-PCR) and viral culturing. Finally, reprocessed respirators were evaluated by users in terms of functionality and comfort. RESULTS: Oven decontamination (75 °C for 45 min) was found to be the simplest decontamination method. Physical and filtration assays indicated that all reprocessing methods were safe after one cycle. Oven decontamination maintained the characteristics of surgical masks and respirators for at least five reprocessing cycles. Viral RNA was detected by RT-PCR in two of the 14 used respirators. Four respirators submitted to viral culture were PCR-negative and culture-negative. Reprocessed respirators used in work shifts were evaluated positively by users, even after three decontamination cycles. CONCLUSION: Oven decontamination is a safe method for reprocessing surgical masks and respirators for at least five cycles, and is feasible in the hospital setting.