ABSTRACT
Frequency of bacterial co-infections among patients with COVID-19 is not high, and over-prescribing of antibiotics may contribute the selection of resistant strains of enterobacteria and gram-negative non-fermenting bacteria. The aim of the study was to assess the local features of antibiotic resistance of K. pneumoniae and its genetic mechanisms against background of the COVID-19 infection pandemic. Material and methods. There was selected 37 carbapenem-resistant K. pneumoniae strains isolated in 2016, 2017 and 2020 from hospitalized patients, including 15 strains, isolated from patients with COVID-19 infection. Minimal inhibitory concentrations (MICs) of meropenem and colistin were determined by broth microdilution method. Determination of MICs of eravacycline, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam was performed using Sensititre diagnostic system on EUMDROXF plates. Susceptibility to 11 combinations of 2 antibiotics was detected by modified method of multiply combination bactericidal testing. For 4 K. pneumoniae strains high-throughput sequencing was performed, followed with the subsequent search for determinants of antibiotic resistance and virulence, assessment of plasmid profiles. Results. All strains were resistant to meropenem (MIC50 32 mg/l, MIC90 128 mg/l) and produced KPC and OXA-48 carbapenemases. Strains isolated in 2016-2017 were susceptible to colistin (MIC <=2 mg/l), in 2020 only 26.7% of the strains retained their susceptibility (MIC50 64 mg/l, MIC90 256 mg/l). Susceptibility to combinations of two antibiotics with colistin included reduced from 84.6-100% in 2016-2017 till 26.6-66.7% in 2020. The strains isolated in 2020 retained their susceptibility to ceftazidime/avibactam (MIC <=1 mg/l). 5 strains resistant to cefiderocol with a MIC 8 mg/l were identified. Strains 2564 and 3125 isolated in 2020 from sputum of patients with COVID-19 infection belonged to different sequence-types (ST12 and ST23) and contained the blaOXA-48 carbapenemase gene, additionally strain 2564 contained the blaKPC-27carbapenemase gene. Resistance to colistin was caused by inactivation of the mgrB genes due to insertion of IS1 and IS5-like transposons. Conclusion. The performed genetic studies demonstrate a diversity of mechanisms of antibiotic resistance in K. pneumoniae leading to the formation of resistance including to antibiotics that haven't been used in Belarus till now.Copyright © 2021 Geotar Media Publishing Group. All Rights Reserved.
ABSTRACT
Post-translational modifications are changes introduced to proteins after their translation. They are the means to generate molecular diversity, expand protein function, control catalytic activity and trigger quick responses to a wide range of stimuli. Moreover, they regulate numerous biological processes, including pathogen invasion and host defence mechanisms. It is well established that bacteria and viruses utilize post-translational modifications on their own or their host's proteins to advance their pathogenicity. Doing so, they evade immune responses, target signaling pathways and manipulate host cytoskeleton to achieve survival, replication and propagation. Many bacterial species secrete virulence factors into the host and mediate hostpathogen interactions by inducing post-translational modifications that subvert fundamental cellular processes. Viral pathogens also utilize post translational modifications in order to overcome the host defence mechanisms and hijack its cellular machinery for their replication and propagation. For example, many coronavirus proteins are modified to achieve host invasion, evasion of immune responses and utilization of the host translational machinery. PTMs are also considered potential targets for the development of novel therapeutics from natural products with antibiotic properties, like lasso peptides and lantibiotics. The last decade, significant progress was made in understanding the mechanisms that govern PTMs and mediate regulation of protein structure and function. This urges the identification of relevant molecular targets, the design of specific drugs and the discovery of PTM-based medicine. Therefore, PTMs emerge as a highly promising field for the investigation and discovery of new therapeutics for many infectious diseases.Copyright © 2021 Bentham Science Publishers.
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Hospital acquired-Staphylococcus aureus (HA-Staphylococcus aureus), particularly methicillin-resistant Staphylococcus aureus (MRSA), are an important source of nosocomial infections with high morbidity and mortality rates. Few reports showed that infections due to HA-Staphylococcus aureus in Saudi Arabia is increasing, particularly infections attributed to HA-MRSA. The study aimed to explore the prevalence and clinical characteristics of HA-Staphylococcus aureus for the first time in Medina, Saudi Arabia. A total of 1262 clinical samples of hospitalized patients were examined for the presence of Staphylococcus aureus through selective culturing on mannitol salt agar. Vitek Compact System and conventional methods were followed to confirm the isolates. Vitek Compact System tested the antimicrobial susceptibility of isolates whereas the standard PCR was employed to detect the genes encoding antimicrobial resistance (mecA and vanA) and virulence factors (tst, et, and LukS-PV). The overall HA-Staphylococcus aureus prevalence was low (6.58%, n = 1262) of which 84.34% (n = 83) were MRSA. Approximately, 57 samples of the 70 MRSA (81.5%) exhibited a multidrug-resistance (MDR) pattern. All the 83 HA-Staphylococcus aureus isolates were negative for the genes encoding toxic shock syndrome toxin, exfoliative toxin, and Panton-Valentine leukocidin. The study was conducted during the Covid-19 pandemic under partial lockdown, restricted hospitalization, and increased disinfection and infection control measures. Therefore, the low prevalence of HA-Staphylococcus aureus should be carefully interpreted and further multicenter investigations could reveal its true incidence in the city. The high prevalence of MDR HA-MRSA is alarming as it highlights inappropriate antibiotic prescriptions to counter staphylococcal infections. HA-Staphylococcus aureus investigated in this study might lack certain virulence factors. However, their MDR traits and invasive nature could worsen the situation if not properly handled. Copyright © 2023 The Author(s).
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In the United States, pyogenic liver abscesses are often due to monomicrobial infection and are rarely documented to be a consequence of Fusobacterium infection, a common cause of Lemierre's syndrome. Recent advances in gut microbial studies have identified Fusobacterium as a commensal gut flora that becomes pathogenic in the setting of dysbiosis resulting from colorectal diseases, such as diverticulitis. While the bacteria's tropism for the liver remains to be elucidated, the virulence pattern of Fusobacterium and the portal venous drainage system have allowed us to understand the bacterium's propensity for causing right hepatic abscesses. In this case report, we detail an immunocompetent man with a history of sigmoid diverticulitis who developed a right hepatic abscess due to Fusobacterium nucleatum, while delineating a review of the literature on the virulent properties of the bacterium and the impact of gut microbiota dysbiosis in its pathogenicity. A descriptive analysis was also performed to identify the characteristics of patients who are at risk in hopes of further improving the clinical diagnostic schema for this condition.
ABSTRACT
Multidrug-resistant K. pneumoniae bacterial strains producing extended range of beta-lactamases or carbapenemases are of serious clinical concern. The aim of the study was to determine the resistance factors of K. pneumoniae strains isolated from the lower respiratory tract of patients diagnosed with community-acquired pneumonia during the COVID-19 pandemic. Materials and methods. The study of resistance to antimicrobial drugs included 138 strains of K. pneumoniae isolated from the sputum of patients treated in infectious diseases monohospitals in the city of Tyumen and the Tyumen region within the period from May 2020 to June 2021. Among the strains examined, 51.4% of them were isolated from SARS-CoV-2 positive patients. The presence of resistance genes was determined by PCR in 71 strains of K. pneumoniae (34 strains from COVID-19-positive and 37 strains from COVID-19-negative patients). Identification of isolated bacterial strains was carried out according to the protein spectra by using a desktop time-of-flight mass spectrometer with matrix laser desorption MALDI-TOF MS (Bruker, Germany). The belonging of the strains to the hypermucoid phenotype was determined using the string test. Sensitivity to antimicrobial drugs was assessed in the disk diffusion method on Muller-Hinton medium. The sensitivity of culture strains to bacteriophage preparations was determined by the drop method (spot-test). In the study, we used "Polyvalent Sextaphage Pyobacteriophage" and "Purified Polyvalent Klebsiella Bacteriophage", JSC NPO Microgen, Russia. Detection of resistance genes to beta-lactam antibiotics by real-time PCR was carried out using the BakRezista kit (OOO DNA-technology, Russia). The results of the study evidence that K. pneumoniae bacteria isolated from COVID-19-positive and COVID-19-negative patients diagnosed with community-acquired pneumonia displayed a high resistance to antimicrobial drugs and commercial phage-containing drugs. Resistance of K. pneumoniae strains was recorded from 50% (to aminoglycosides and carbapenems) to 90% (to inhibitor-protected penicillins). Sensitivity to bacteriophages was noted on average in no more than 20% of strains. It is important to emphasize that strains isolated from COVID-19-positive patients more often showed a hypermucoid phenotype, suggesting a high bacterial virulence, and also showed greater resistance to all groups of antibacterial drugs examined in the study, which is confirmed by the presence of resistance genes of the ESBL group and carbapenemase. The results of the study suggest that the high level of resistance of K. pneumoniae strains isolated from COVID-19-positive patients is associated with immunosuppression provoked by the SARS-CoV-2 virus, which contributes to their colonization by more virulent strains.Copyright © 2022 Saint Petersburg Pasteur Institute. All rights reserved.
ABSTRACT
Severe course of COVID-19 in inpatients can be caused by a number of reasons, including viral and bacterial superinfections. Empirical use of antibiotics, as well as poor infectious control stimulate the emergence and spread of multidrug-resistant bacteria. Klebsiella pneumoniae is the most common carbapenemase-producing bacterial pathogen causing nosocomial infections. These strains became significantly widespread during the COVID-19 pandemic. Objective. To analyze phenotypic and genetic characteristics of K. pneumoniae strains as the dominant bacterial pathogen in severe COVID-19 patients in the intensive care unit. Patients and methods. This study included 38 COVID-19 patients (including 6 patients with severe disease) treated in the intensive care units of Moscow and Saint Petersburg hospitals for infectious diseases between July 2020 and December 2020. All patients signed an informed consent to participate in the study;patient data was anonymized. The following samples were collected: sputum, bronchoalveolar lavage, and nasopharyngeal swabs. We performed bacteriological identification of isolated bacterial strains, drug susceptibility testing, and whole genome sequencing of K. pneumoniae strains. Results. The majority of K. pneumoniae strains isolated from patients with severe COVID-19 contained clusters of aerobactin and enterobacterin genes. However, some of them (strains 90 and 124) also contained clusters of yersiniabactin genes. These genes are associated with high virulence and ability to form biofilms. The isolated strains belonged to four sequence types (ST874, ST395, ST147, ST15) that are characterized by high virulence and antibiotic resistance. These K. pneumoniae strains can be considered as one of the major causes of severe and lethal COVID-19. Conclusion. Our findings suggest that the detection rate of K. pneumoniae in COVID-19 patients increased from 30% to 70% during the pandemic. Phenotypic tests demonstrated that more than 80% of the strains were resistant to most antibiotics used in patients with complicated COVID-19. The combination of hypervirulence and antibiotic resistance is crucial for nosocomial transmission of these strains and their effect on the disease outcome. The emergence of hyper-resistant pathogens necessitates regular epidemiological monitoring and robust infection control in Russian hospitals, especially in intensive care units.
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Background: HPV vaccination is highly effective at preventing several squamous cell carcinomas. However, the uptake of this vaccine remains sub-optimal in the US, with further exacerbation of this poor uptake during the pandemic. This study aims to describe changes and barriers to HPV vaccination during the COVID-19 pandemic as observed by healthcare professionals (HCPs) in the state of Texas. Methods: Data for this study were derived from a statewide cross-sectional survey of HCPs in the state of Texas (n=1283). Survey instruments were developed at MD Anderson Cancer Center, and reviewed by its IRB. Survey frequencies were used to estimate for the proportional distribution of changes as observed by HCPs regarding HPV vaccination i) uptake ii) hesitancy and iii) refusal during the COVID-19 pandemic. HCPs who observed increases in vaccination hesitancy or refusal, were then asked for the reasons cited by their patients. Survey frequencies were then used to determine the proportional distribution of the reasons cited for HPV vaccination hesitancy and refusal during the pandemic. All statistical analysis were conducted using R version 3.5.2. Results: Overall, 730 HCPs responded to the study questions of interest. A predominant proportion of respondents were employed in group practice settings or university teaching/affiliated hospitals. About 20% of HCPs in Texas observed decreases in HPV vaccination uptake. Observed increments in HPV vaccination hesitancy and refusal were reported by 17.1% and 14.8% of HCPs, respectively. Among HCPs who observed increased hesitancy and refusal, difficulties in scheduling clinic visit during the pandemic and fear of contracting corona virus during the clinic visit were the most cited reasons. Discussion: Findings of the index study suggest that the COVID-19 pandemic has had a negative impact on HPV vaccination in Texas. Results identify perceived barriers to HPV vaccination unique to the pandemic. With the pandemic still ongoing, amid the emergence of novel strains with heightened virulence, despite the presence of highly effective FDA-approved vaccines, findings of this study provides useful insight for public health interventions, as well as to guide physician-patient interactions around HPV vaccination.
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This study was conducted to investigate isolation and molecular identification of Acinetobacter baumannii in COVID-19 patients from clinical specimens includes, sputum, lower respirayory secretion of patients admitted to Medical Teaching City and Al-Yarmouk Teaching Hospital in Baghdad, Al-Hussein teaching hospital in Karbala, with study the rate of biofilm formation in Acinetobacter baumannii. In addition to investigate the to determine the frequency of responsible virulence genes. During a period from the first of October 2020 to the end of May 2021. A total of 100 respiratory patients 25 patients positive A. baumannii enrolled in this study, patient’s age ranged from (≤ 25-88) year, 9 female and 16 male. A. baumannii were isolated and diagnosed primarily by characteristic features on culture media and biochemical tests then by VITEK 2 system to confirm diagnosis. A total of (25%) Acinetobacter baumannii were isolated in this study. The highest proportion (21%) of Acinetobacter baumannii was from sputum specimens, which include 27.59% in males and 21.43% in females, followed by (4%) in lower respiratory secretion of patients, which is all from males. According of infection a 25 A. baumannii isolated from covid-19 patients. the result showed that positive of A. baumannii 9 (36.0%) of isolated respiratory patients of Negative covid-19, while 16(64.0%) of positive A. baumannii of positive covid-19. In present study, out of 16 isolates of Covid 19 patient that were ITS gene (68.80%). In conclusion, high frequency of Acinetobacter baumannii infection was observed among (>45 year) and covid-19 patients.
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This study was conducted in the College of Medicine, Wasit University Cooperation with the Al Zahraa Teaching Hospital, Al Kut Hospital laboratory in Wasit, Al-Karama hospital and private clinics of internal from the period of November 2020 to April 2021. It has been carried out on 150 samples of nasal and throat swabs from post COVID-19 patients who suffered from nasal and throat infection from both sex (male &female). The infections were in age group between (4-88) years. The results of throat swabs showed that 84(56%) were infected with bacteria and 66(44%) non-infected and the results of nasal swabs showed that 67(44.66%) were infected with bacteria and 83(55.33%) non-infected. The results of culture appeared that from 150 throat swab sample found that 66(44%) samples were no growth and 84(56%) were infected with bacteria. The results were Pseudomonas aeruginosa 12/150(8%), E. coli 9/150(6%), Enterobacter spp. 2/150(1.33), Pseudomonas spp. 2/ 150(1.33%), Klebsiella spp. 2/150(1.33%), Staphylococcus spp. 4/150(2.66%), Staphylococcus aureus 4/150(2.66%), Streptococcus viridans 43/150(28.66%) and mix of Staphylococcus spp. and Streptococcus viridans 6/150(4%). Out of 150 nasal swab sample found that 83/150(55.33%) sample were no growth and 67/150(44.67%) were infected with bacteria. The result were Pseudomonas aeruginosa 7/150(4.66%), E.coli 3/150(2%), Enterobacter spp. 2/150(1.33), Pseudomonas spp. 5/ 150(3.33%), Klebsiella spp. 6/150(4%), Staphylococcus spp. 12/150(8%), Staphylococcus aureus 3/150(2%), Streptococcus viridans 24/150(16%) and mix of Staphylococcus spp. and Streptococcus viridans 3/150(5.33%) and mix of E. coli and Pseudomonas spp. 2/150(1.33%). Antimicrobial sensitivity for Pseudomonas aeruginosa showed sensitivity to Amikacin (100%), levofloxacin (90%), Meropenem (90%), Cefipime (70%), Imipenem (60%), Aztreonam (30%), Chloramphenicol (5%), and don’t show sensitive to Tetracycline, Pipracillin, Ampicillin, Trimethoprim-Sulphamethoxazole and Clarithromycin. To facilitate species identification, used molecular methods (PCR analysis) by 16s rRNA primers gene for more predominant bacteria isolates (Pseudomonas aeruginosa) isolates studied were detected by 16S rRNA gene and there virulence factors based on multiplex polymerase chain reaction technique amplifying five virulence factors primer for Pseudomonas aeruginosa (aprA, filC, toxA, pilA, pslA). In this study, we concluded that the production of virulence factors genes in Pseudomonas aeruginosa is important to human infection especially (ToxA) gene and the PCR technique was very specific and fast method in detection virulence factor genes in Pseudomonas aeruginosa.
ABSTRACT
Antimicrobial resistance (AMR) is among the top 10 global public health threats. Antimicrobial overuse in part because of the overload of ICU departments in the context of the COVID-19 pandemic facilitates the phenomenon. Designing novel effective antimicrobial strategies necessitates the development of new methodologies of antimicrobial susceptibility testing (AST) instead of routinely used laboratory approaches that do not consider recent findings concerning the crucial impact of structural complexity inherent for macroorganism tissues, and physical characteristics of the environment on microbial population behavior and biological properties. Liquid crystal (LC) materials combining properties of both the liquid and the solid phase offer tremendous potential for the development of various spatially structured liquid model environments and solid surfaces for studying tripartite system bacterium-antibiotic-bacteriophage. Our pilot study was aimed to examine the behavior of the population of Proteus vulgaris ? the representative of the third most common etiological factor of nosocomial and catheter-associated urinary tract infections ? in different microcosms based on a lyotropic nematic liquid crystal. The study design included examining the bacterial growth, motility, and morphology under the transition of pre-grown population from different isotropic nutrient media to anisotropic microcosms based on LC. Growth kinetics, motility pattern as well as morphotype conversion from swimmers to swarmers changed significantly after the transition of the bacterial population to different microcosms based on LC as compared to those in isotropic conditions. The significance of swarming motility and swarming-specific induction of the virulence factors of Proteus for its pathogenicity and AMR has been debated widely yet remains unclear. Our findings indicate the attractiveness of artificial spatially structured microcosms based on LC for the study of these phenomena.
ABSTRACT
Multidrug-resistant K. pneumoniae bacterial strains producing extended range of beta-lactamases or carbapenemases are of serious clinical concern. The aim of the study was to determine the resistance factors of K. pneumoniae strains isolated from the lower respiratory tract of patients diagnosed with community-acquired pneumonia during the COVID-19 pandemic. Materials and methods. The study of resistance to antimicrobial drugs included 138 strains of K. pneumoniae isolated from the sputum of patients treated in infectious diseases monohospitals in the city of Tyumen and the Tyumen region within the period from May 2020 to June 2021. Among the strains examined, 51.4% of them were isolated from SARS-CoV-2 positive patients. The presence of resistance genes was determined by PCR in 71 strains of K. pneumoniae (34 strains from COVID-19-positive and 37 strains from COVID-19-negative patients). Identification of isolated bacterial strains was carried out according to the protein spectra by using a desktop time-of-flight mass spectrometer with matrix laser desorption MALDI-TOF MS (Bruker, Germany). The belonging of the strains to the hypermucoid phenotype was determined using the string test. Sensitivity to antimicrobial drugs was assessed in the disk diffusion method on Muller-Hinton medium. The sensitivity of culture strains to bacteriophage preparations was determined by the drop method (spot-test). In the study, we used “Polyvalent Sextaphage Pyobacteriophage” and “Purified Polyvalent Klebsiella Bacteriophage”, JSC NPO Microgen, Russia. Detection of resistance genes to beta-lactam antibiotics by real-time PCR was carried out using the BakRezista kit (OOO DNA-technology, Russia). The results of the study evidence that K. pneumoniae bacteria isolated from COVID-19-positive and COVID-19-negative patients diagnosed with community-acquired pneumonia displayed a high resistance to antimicrobial drugs and commercial phage-containing drugs. Resistance of K. pneumoniae strains was recorded from 50% (to aminoglycosides and carbapenems) to 90% (to inhibitor-protected penicillins). Sensitivity to bacteriophages was noted on average in no more than 20% of strains. It is important to emphasize that strains isolated from COVID-19-positive patients more often showed a hypermucoid phenotype, suggesting a high bacterial virulence, and also showed greater resistance to all groups of antibacterial drugs examined in the study, which is confirmed by the presence of resistance genes of the ESBL group and carbapenemase. The results of the study suggest that the high level of resistance of K. pneumoniae strains isolated from COVID-19-positive patients is associated with immunosuppression provoked by the SARS-CoV-2 virus, which contributes to their colonization by more virulent strains.
ABSTRACT
Background: COVID-19 has a high rate of severe infection and mortality, which is thought to be due in part to a lack of natural immunity and viral replication in the lower respiratory tract, as well as superinfections. COVID-19 patients suffer to infect with secondary bacterial infection and the ability of these pathogens to infect the host and causing disease is referred to as virulence factors. Methodology: 200 samples from patients with COVID-19 were collected from blood, pharyngeal swabs, sputum, and nasal swab. Reverse transcription-polymerase chain reaction (RT-PCR), was used to confirm the disease. Biochemical tests, culture media and a Vitek-2 compact system were used to identify the isolates. AST, Biofilm formation, hemolysin and lipase were done on all isolates. Results: Forty-five (23%) isolates were obtained from a total of 200 samples while 77% showed negative growth. All isolates were distributed between gram positive as Staphylococcus aureus and gram negative such as Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae. High resistance to antibiotics was detected which the isolates classified to MDR and XDR as showed S. aureus (40%,60%), A. baumannii (30%, 70%), P. aeruginosa (20%, 80%) and K. pneumonia (45%, 55%) respectively. Virulence factors of the SBIs associated with Antibiotics resistance (MDR and XDR) in COVID-19 patients showed 100% of both S. aureus and P. aeruginosa hemolysin positive while all the isolates of A. baumannii and K. pneumonia were negative. The results showed that 25% of MDR S. aureus and (75%) XDR, A. baumannii MDR (20%) and (80%) XDR, P. aeruginosa (20%) MDR and (80%) XDR and K. pneumonia (25%) MDR and (75%) XDR. Biofilm formation showed S. aureus (20%) MDR and (80%) XDR were produced biofilms, A. baumannii (15%) MDR and (85%) XDR, P. aeruginosa (10%) MDR and (90%) XDR and K. pneumonia (25%) MDR and (75%) XDR. Conclusions: Biofilm formation, hemolysin and lipase are virulence factors that confirmed secondary bacterial infection with high antibiotic resistance in COVID-19 patients which due to sever infection and elongated the period of healing as well as the side effects and complication during the infection period which were noticed in the most cases under the study.
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Introduction: India recently faced a devastating second outbreak of COVID-19 infection, in which a majority of the viral sequences were found to be of the B.1.617.2 lineage. While India and the world focused on vaccination, reports of vaccine evasion by the virus, termed 'breakthrough cases', emerged worldwide. Materials and Methods: We analysed whole genome sequences of 150 SARS-CoV-2 viral samples isolated at our laboratory. We retrospectively found 9 cases of breakthrough infection, five of whom were fully, and four partially vaccinated. We followed-up these patients and can report that the variant lineages associated with these cases were B.1.617, B.1, and A. The mutations seen in these sequences in the Spike and ORF regions would have produced amino acid changes known to improve viral replication, confer drug resistance, influence host-cell interaction, and lead to antigenic drift. Increased virulence culminating in vaccine evasion may be inferred from these mutations. India, recently faced a devastating second outbreak of COVID-19 infection, in which a majority of the viral sequences were found to be of the B.1.617.2 lineage. While India and the world focused on vaccination, reports of vaccine evasion by the virus, termed 'breakthrough cases', emerged worldwide. We isolated mRNA from SARS-CoV-2 samples and outsourced them for whole genome sequencing. Results: We noticed that nine individuals had been fully (two doses of vaccine) or partially (one dose) vaccinated at least 14 days before infection. When we examined the sequences from these individuals, we found amino acid changes in the spike and NSP proteins, which were predicted to confer increased virulence upon the virus. We report the presence of three strains in the breakthrough cases;A, B.1, and B.1.617 (Nextstrain Clade G). We found one mutation, NSP6 T77A, that was present in both A and B.1 strains in the breakthrough cases, but not in other A and B.1 strains isolated, from patients of the same city. Additionally, we found multiple changes in the non-structural NSP proteins, which enable faster viral replication. Conclusion: It is clear from our case series that the strains A, B.1, and B.1.617 can attain increased virulence culminating in vaccine evasion.
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Background:Genus Tricosporon consists of basidiomycetous yeast that form a part of the human microbiota.They cause an array of human diseases, both in imunocompetant and immunocompromised patients. They are the second most commonly reported cause of disseminated infections in humans. Their ability to form Biofilms make them a potential agent of Catheter associated Fungemia. They exhibit virulence factors like Biofilm formation, hemolysis and produce enzymes like proteases and phospholipases that increases the pathogenicity by breaking down the proteins and dis- rupting the host cell membranes. The proteolytic activity plays an important role in its pathogenicity by facilitating inva- sion through degradation of keratin and collagen. Methods:This observational period study was performed at our hospital from 20/06/2020 to 20/10/2020.The isolates were subjected to tests to demonstrate virulence factors. Determination of phospholipase activity was performed using using egg yolk agar, hemolytic activity by SDA with 7% sheep blood, esterase activity was determined by using Tween -80 opacity test medium and the production of Biofilm formation was done by micro titre plate method. All results were recorded. The isolates were confirmed by MALDI TOF mass spectrometry. Results:1.Colony morphology 2.Urease production using christensons urea agar (2%) 3.Phenotypic and Biochemical test result were per- formed and tabulated. Proteomic confirmation results are awaited. [Formula presented] Conclusions:Knowing the virulence factor and the commonly occurring Trichosporon species aids in understanding the pathogenesis and to plan strategic treatment modalities
ABSTRACT
Background:Candida species are yeast like fungi that form a part of the human microbiota. They are seen as normal flora in the mouth, gastrointestinal tract, genito urinary tract, respiratory tract and skin. However they have the potential to cause invasive my- cosis.They also colonise IV lines and cannulae and form biofilms that makes treatment difficult. Candidemia, a blood stream infection caused by Candida species, are the most common forms of invasive candidiasis. There are few pointers to clinical suspicion like unre- sponsiveness to antibacterial agents, diabetes, stem cell transplant, patients on antibiotics, ICU stay, steroid therapy, immunosup- presants, prosthetic devices, presence of IV/central lines, urinary catheters, TPN, CRF etc. Methods:Candida species were isolated from blood cultures using conventional and automated (BACTEC) methods over a 4 month period from 20.06.2020 - 20.10.2020. Speciation was done using phenotypic methods, Biochemical tests, Vitek and confirmed by MALDI-TOF mass spectrometry. The results of l Gram’s staining l Colony characteristics l growth and ap- pearance by Dalmaus technique l growth in 6.5% NaCl l Temperature differentiation l Growth in the pres- ence of Actidione l Production of Urease l Sugar assimilation were tabulated. Anti -fungal susceptibility testing was done in MHA with 2% glucose according to CLSI guidelines. Biofilm formation was demonstrat- ed by micro-titre plate method. [Formula presented] Results:The results of the phenotypic tests - Awaited. Species distribution using High Chrome Candida agar (FIGURE 1). Confirmation using MALDI-TOF Mass Spectrometry - Results awaited. Confirmation of Candida auris, famata, connerii and 1 rare species by colony PCR - Results awaited Biofilm production by Microtitre plate method and Anti-fungal susceptibility pattern - Results awaited. Conclusions:This study throws light on the Candida species isolated in blood during the COVID19 pandem- ic, over a 4 month period in our institution along with their susceptibility patterns. The ability to form bio - films which is the virulence factor needed for bloodstream/catheter associated fungemia is assessed in our study