Retrospective Analysis of the SARS-CoV-2 Infection Profile in COVID-19 Positive Patients in Vitoria da Conquista, Northeast Brazil.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is responsible for causing Coronavirus Disease-2019 (COVID-19), a heterogeneous clinical condition that manifests varying symptom severity according to the demographic profile of the studied population. While many studies have focused on the spread of COVID-19 in large urban centers in Brazil, few have evaluated medium or small cities in the Northeast region. The aims of this study were: (i) to identify risk factors for mortality from SARS-CoV-2 infection, (ii) to evaluate the gene expression patterns of key immune response pathways using nasopharyngeal swabs of COVID-19 patients, and (iii) to identify the circulating SARS-CoV-2 variants in the residents of a medium-sized city in Northeast Brazil. A total of 783 patients infected with SARS-CoV-2 between May 2020 and August 2021 were included in this study. Clinical-epidemiological data from patients who died and those who survived were compared. Patients were also retrospectively divided into three groups based on disease severity: asymptomatic, mild, and moderate/severe. Samples were added to a qPCR array for analyses of 84 genes involved with immune response pathways and sequenced using the Oxford Nanopore MinION technology. Having pre-existing comorbidity; being male; having cardiovascular disease, diabetes, and/or chronic obstructive pulmonary disease; and PCR cycle threshold (Ct) values under 22 were identified as risk factors for mortality. Analysis of the expression profiles of inflammatory pathway genes showed that the greater the infection severity, the greater the activation of inflammatory pathways, triggering the cytokine storm and downregulating anti-inflammatory pathways. Viral genome analysis revealed the circulation of multiple lineages, such as B.1, B.1.1.28, Alpha, and Gamma, suggesting that multiple introduction events had occurred over time. This study's findings help identify the specific strains and increase our understanding of the true state of local health. In addition, our data demonstrate that epidemiological and genomic surveillance together can help formulate public health strategies to guide governmental actions.

Molecular characterization of methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from human milk samples in Brazil.

Human milk is the best nutrient for infants. The donor human milk is stored in a milk bank before pasteurization. However, the human milk is not sterile and could be colonized with different types of bacteria. Many studies have shown S. aureus to be the most prevalent potential pathogen detected in human milk. This study characterized 22 methicillin-resistant and methicillin-sensitive Staphylococcus aureus isolates from raw human milk for the presence of virulence genes and agr type. Moreover, the genotypic as identified characterization was realized. The presence of virulence genes sei, seg, sec, seh, and etb was identified in resistant and sensitive strains. We observed the predominance of agr type II. The presence of SCCmec IV (67%, 4/6) and V (33%, 2/6) characterized resistant strains as CA-MRSA. Endemic lineages detected (ST1635/CC5-t002, ST5/CC5-t002, ST72/CC5-t126, ST1/CC1-t127, ST45/CC45-t065, and ST398/t1451) could be related to epidemic clones, such as USA800/ST5, USA700/ST72, USA400/ST1, USA600/ST45, and ST398. This study made it possible to understand the characteristics of virulence and clonality of some strains that circulate in breast milk in our region. The discovery of human milk colonization by MSSA and MRSA strains with molecular characteristics similar to infectious clones spread globally demonstrates the importance of monitoring strains that can spread and cause serious infections.

Prevalence of methicillin-resistant Staphylococcus aureus colonization among healthcare workers at a tertiary care hospital in northeastern Brazil.

BACKGROUND: Staphylococcus aureus is a human pathogen of clinical importance related to a variety of infections. AIM: The objective of this study was to analyze the molecular and epidemiological characteristics of S. aureus obtained from healthcare professionals (HCP) of a hospital in southwestern Bahia, Brazil. METHODS: Samples were collected from hands, nasal cavity, and laboratory coats of 80 HCP. The bacterial isolates recovered from 240 samples were identified as S. aureus, and then analyzed for their antimicrobial resistance profile, genotypic characterization, and pathogenicity. FINDINGS: 178 isolates were identified as S. aureus, being mostly isolated from the nasal cavity. Thirty isolates (16.8%) were characterized as MRSA. The virulence gene frequency varied according to isolate source. All virulence genes were identified in at least one hand isolate. Isolates from laboratory coats did not show seb and pvl. Isolates from the nasal cavity did not exhibit pvl. The SCCmec type I was identified in 56.7% of MRSA isolates. Among MRSA isolates, 14 PFGE pulsotypes were characterized, with profile A being predominant (nine isolates). Clonal complexes CC5, CC45, and CC398 were found. MRSA isolates induced cytokine gene expression in macrophages, with IL-10 and IL-17 being expressed more often. CONCLUSION: We found a high colonization rate for S. aureus among HCP. Moreover, we observed that MRSA strains presented different virulence factors and could induce cytokine gene expression, indicating an urgent need to control colonization rates of HCP by MRSA isolates in order to protect hospital patients and the general public.

Molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from hospital and community environments in northeastern Brazil.

This study characterized 30 MRSA isolates from intensive care unit (ICU) environment and equipment surfaces and healthy children. The SCCmec types I, IVa and V were detected in HA-MRSA isolates while CA-MRSA showed the SCCmec type IVa and V. Most isolates were classified as agr group II. All isolates presented the sei gene, and only HA-MRSA were positive for etb e tst genes. Three genotypes were related to Pediatric (ST5/SCCmecIV) and Berlin (ST45/SCCmecIV) clones. The present study showed molecular similarity between CA- and HA-MRSA isolates in hospital and community settings in a Brazilian region.

Molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from hospital and community environments in northeastern Brazil

ABSTRACT This study characterized 30 MRSA isolates from intensive care unit (ICU) environment and equipment surfaces and healthy children. The SCCmec types I, IVa and V were detected in HA-MRSA isolates while CA-MRSA showed the SCCmec type IVa and V. Most isolates were classified as agr group II. All isolates presented the sei gene, and only HA-MRSA were positive for etb e tst genes. Three genotypes were related to Pediatric (ST5/SCCmecIV) and Berlin (ST45/SCCmecIV) clones. The present study showed molecular similarity between CA- and HA-MRSA isolates in hospital and community settings in a Brazilian region.

Ureaplasma diversum and Its Membrane-Associated Lipoproteins Activate Inflammatory Genes Through the NF-κB Pathway via Toll-Like Receptor 4.

Objectives:Ureaplasma diversum is a pathogen of cows that may cause intense inflammatory responses in the reproductive tract and interfere with bovine reproduction. The aims of this study were to evaluate the immune response of bovine blastocysts and macrophages to U. diversum infection and to evaluate the invasion capacity of this microorganism in bovine blastocysts. Methods: Viable and heat-inactivated U. diversum strains ATCC 49782 and CI-GOTA and their extracted membrane lipoproteins were inoculated in macrophages in the presence or absence of signaling blockers of Toll-Like Receptor (TLR) 4, TLR2/4, and Nuclear Factor KB (NF-κB). In addition, the same viable U. diversum strains were used to infect bovine blastocysts. RNA was extracted from infected and lipoprotein-exposed macrophages and infected blastocysts and assayed by qPCR to evaluate the expression of Interleukin 1 beta (IL-1ß), Tumor Necrosis Factor Alpha (TNF-α), TLR2 and TLR4 genes. U. diversum internalization in blastocysts was followed by confocal microscopy. Results: Both Ureaplasma strains and different concentrations of extracted lipoproteins induced a higher gene expression of IL-1ß, TNF-α, TLR2, and TLR4 in macrophages (p < 0.05) when compared to non-infected cells. The used blockers inhibited the expression of IL-1ß and TNF-α in all treatments. Moreover, U. diversum was able to internalize within blastocysts and induce a higher gene expression of IL-1b and TNF- α when compared to non-infected blastocysts (p < 0.05). Conclusion: The obtained results strongly suggest that U. diversum and its lipoproteins interact with TLR4 in a signaling pathway acting via NF-kB signaling to stimulate the inflammatory response. This is the first study to evaluate the in vitro immunological response of macrophages and bovine blastocysts against U. diversum. These results may contribute to a better understanding of the immunomodulatory activity and pathogenicity of this infectious agent.

Community-acquired methicillin-resistant Staphylococcus aureus carrying SCCmec type IV and V isolated from healthy children attending public daycares in northeastern Brazil

Abstract Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) have increasingly been reported in healthy communities. This study aimed to assess the rate of S. aureus in general and MRSA in particular from nasal secretion of children in daycare centers in Vitória da Conquista, Brazil. The isolates were identified based on morphology, biochemical tests and by PCR. Detection of virulence genes, biofilm production, and susceptibility test by disk diffusion agar were performed. MRSA isolates were characterized by spa, SCCmec, and multilocus sequence typing (MLST). S. aureus were recovered from 70 (47.3%) of 148 children. Among the 11 MRSA strains (15.7%), two SCCmec types (IV and V) were detected. MLST identified four STs related to three clonal complexes (CC): 5, 45, and 398. Four spa types were found circulating in this setting. Resistance of S. aureus isolates to ampicillin, erythromycin, ciprofloxacin, clindamycin, and tetracycline was 80%, 32.8%, 7.1%, 7.1% and 4.3%, respectively. One isolate presented intermediate resistance to vancomycin detected by Etest methodology. All strains were biofilm producers. The virulence genes seb, sec, spa, and pvl were detected in some isolates. This study revealed a high rate of children carrying MRSA among healthy attendees in daycare centers in Vitória da Conquista, Brazil.

Community-acquired methicillin-resistant Staphylococcus aureus carrying SCCmec type IV and V isolated from healthy children attending public daycares in northeastern Brazil.

Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) have increasingly been reported in healthy communities. This study aimed to assess the rate of S. aureus in general and MRSA in particular from nasal secretion of children in daycare centers in Vitória da Conquista, Brazil. The isolates were identified based on morphology, biochemical tests and by PCR. Detection of virulence genes, biofilm production, and susceptibility test by disk diffusion agar were performed. MRSA isolates were characterized by spa, SCCmec, and multilocus sequence typing (MLST). S. aureus were recovered from 70 (47.3%) of 148 children. Among the 11 MRSA strains (15.7%), two SCCmec types (IV and V) were detected. MLST identified four STs related to three clonal complexes (CC): 5, 45, and 398. Four spa types were found circulating in this setting. Resistance of S. aureus isolates to ampicillin, erythromycin, ciprofloxacin, clindamycin, and tetracycline was 80%, 32.8%, 7.1%, 7.1% and 4.3%, respectively. One isolate presented intermediate resistance to vancomycin detected by Etest methodology. All strains were biofilm producers. The virulence genes seb, sec, spa, and pvl were detected in some isolates. This study revealed a high rate of children carrying MRSA among healthy attendees in daycare centers in Vitória da Conquista, Brazil.