Nhiễm trùng huyết cấy máu dương tính ở bệnh nhân mắc Covid-19

TÓM TẮT Đặt vấn đề: Nhiễm Covid-19 đồng thời nhiễm trùng huyết là một bệnh nặng, nguy cơ tử vong cao. Nghiên cứu này nhằm mô tả đặc điểm bệnh nhân Covid-19 nhiễm trùng huyết cấy máu dương tính; đặc điểm vi khuẩn gây nhiễm trùng huyết và mức độ đáp ứng kháng sinh của vi khuẩn trên kháng sinh đồ. Phương pháp nghiên cứu: Mô tả cắt ngang, 26 bệnh nhân Covid-19 cấy máu dương tính từ 8/2021 - 10/2021. Kết quả: 26 bệnh nhân có độ tuổi trung bình 57,89 (nhỏ nhất 32; lớn nhất 78) tuổi, 57,7% bệnh nhân lớn hơn 60 tuổi, nữ nhiều hơn nam, 69,23% bệnh nhân có bệnh nền, thời gian nằm viện trung bình là 16,35 ngày, 84,62% bệnh nhân cấy máu dương tính sau 48 giờ nằm viện, 23,08% bệnh nhân hồi phục sau điều trị. 96,15% bệnh nhân tăng CRP, 100% bệnh nhân tăng Procalcitonin, 86,46% bệnh nhân tăng bạch cầu chung và bạch cầu trung tính. Vi khuẩn gây nhiễm trùng huyết nhiều nhất là Acinetobacter baumannii, Escherichia coli, Burkholderia cepacia với tỷ lệ 19,23% mỗi loại. Vi khuẩn Gram âm nhạy cảm nhiều nhất với nhóm kháng sinh Carbapenem, Aminoglycosid, vi khuẩn Gram dương nhạy cảm nhiều với kháng sinh Linezolid, Vancomycin. Kết luận: Nhiễm trùng huyết trên bệnh nhân Covid làm tăng tỷ lệ tử vong, xác định chủng vi khuẩn và điều trị kháng sinh tích cực phù hợp với từng chủng vi khuẩn là cần thiết. ABSTRACT POSITIVE BLOOD CULTURE SEPSIS IN COVID-19 PATIENTS Background: Infection with Covid 19 and sepsis is a severedisease that leads to a high risk of death. This study aims to describe the characteristics of Covid-19 patients with positive blood culture, elements of bacteria causing sepsis, and the level of antibiotic response of bacteria on the antibiotic chart. Methods: A cross - sectional descriptive study was conducted on 26 Covid-19 patients with positive blood culture 8/2021-10/2021. Result: Twenty - six Covid-19 patients had an average age of 57.89 years (range: 32 - 78). Of these, 57.7% of patients were older than 60 years; women were more than men. 69.23% of patients had a medical history of the disease. The average treatment time was 16.35 days; 84.62% of patients had positive blood cultures after 48 hours of treatment. 23.08% of patients were recovered after treatment. 96.15% of patients increased CRP, 100% of patientsincreased Procalcitonin, and 86.46% increased leukocytosis and neutrophils. The bacteria that caused the most sepsis are Acinetobacter baumannii, Escherichia coli, Burkholderia cepacia with 19.23%. Gram - negative bacteria were most sensitive to Carbapenem, Aminoglycoside antibiotics. Gram - positive bacteria were more susceptible to Linezolid and Vancomycin antibiotics. Conclusion: Sepsis with positive blood culture in covid patients increases the mortality rate. Identifying bacterial strains and appropriate aggressive antibiotic treatment for each bacterial is necessary. Keywords: Sepsis, bacteria, sensitive, Covid-19.

MEILIODOSIS - AN ENIGMA WITH VARYING ANTIBIOTIC RESPONSE

Melioidosis or Whitmore's disease is an infection of humans and animals caused by aerobic gram negative bacillus Burkholderia pseudomallei. This infection with a wide clinical spectrum is predominantly present in tropical climates, mainly Southeast Asia and Northern Australia. The clinical manifestations include pneumonia, skin ulcers or abscesses, osteomyelitis, prostatitis, encephalomyelitis and fulminant septic shock. The denitive diagnosis is made by a positive culture of Burkholderia pseudomallei. The bacteria is innately resistant to 6 classes of commonly used antibiotics. CDC recommends an intensive phase of intravenous antibiotics for 10 to 14 days followed by eradication therapy with oral antibiotics for 3 – 6 months. The intravenous agents effective against the bacteria are meropenem and ceftazidime. Trimethoprim sulfamethoxazole and amoxicillin/clavulanic acid are the oral antimicrobial agents used. Here we present two cases of Melioidosis, at opposite ends of the spectrum with varying antibiotic response. One patient is a young non immunocompromised female and the second an elderly immunocompromised (T2DM) male, both presented with skeletal melioidosis.

Evaluation of Antibiotic Tolerance in Pseudomonas aeruginosa for Aminoglycosides and Its Predicted Gene Regulations through In-Silico Transcriptomic Analysis

Pseudomonas aeruginosa causes chronic infections, such as cystic fibrosis, endocarditis, bacteremia, and sepsis, which are life-threatening and difficult to treat. The lack of antibiotic response in P. aeruginosa is due to adaptive resistance mechanism, which prevents the entry of antibiotics into the cytosol of the cell to achieve tolerance. Among the different groups of antibiotics, aminoglycosides are used as a parenteral antibiotic for the treatment of P. aeruginosa. This study aimed to determine the kinetics of antibiotic tolerance and gene expression changes in P. aeruginosa exposed to amikacin, gentamicin, and tobramycin. These antibiotics were exposed to P. aeruginosa at their MICs and the experimental setup was monitored for 72 h, followed by the measurement of optical density every 12 h. The growth of P. aeruginosa in the MICs of antibiotics represented the kinetics of antibiotic tolerance in amikacin, gentamicin, and tobramycin. The transcriptomic profile of antibiotic exposed P. aeruginosa PA14 was taken from the Gene Expression Omnibus (GEO), NCBI as microarray datasets. The gene expressions of two datasets were compared by test versus control. Tobramycin-exposed P. aeruginosa failed to develop tolerance in MICs of 0.5 µg/mL, 1 µg/mL, and 1.5 µg/mL, whereas amikacin- and gentamicin-treated P. aeruginosa developed tolerance. This illustrated the superior in vitro response of tobramycin over gentamicin and amikacin. Further, in silico transcriptomic analysis of tobramycin-treated P. aeruginosa resulted in differentially expressed genes (DEGs), enriched in 16s rRNA methyltransferase E, B, and L, alginate biosynthesis genes, and several proteins of the type II secretion system (T2SS) and type III secretion system (T3SS). The regulation of mucA in alginate biosynthesis, and gidB in RNA methyltransferases, suggested an increased antibiotic response and a low probability of developing resistance during tobramycin treatment. The use of tobramycin as a parenteral antibiotic with its synergistic combination might combat P. aeruginosa with increased response.

Assessment of Lung Parenchyma Recovery after Antibiotic Administration using Lung Ultrasound in Critically Ill Patients with Pneumonia

Background: Pneumonia is a common cause of Intensive care unit (ICU) admission, requiring frequent imaging for following up parenchymal lung involvement and antibiotic response. Being bedside and non-invasive technique; lung ultrasound (US) is increasingly used in ICU. Objectives: Assessing accuracy of lung ultrasound in detecting parenchymal lung recovery following antibiotic administration in critically ill patients with pneumonia. Methods: Fifty patients with pneumonia were included in the study with time-dependent analysis for APACHEII, CURB-65 and modified CPIS. Lung US at day 0 described basal lung condition then according to changes in lung parenchyma, US score could be first calculated at day 3. At day 5 US score was calculated again and changes in score (delta score) was calculated to asses ability of US to predict early good antibiotic response and finally lung US was repeated at day 7, score calculated to detect lung parenchyma recovery and compared with follow up CT for accuracy and agreement. Air bronchogram was reported whenever seen, described as static or dynamic and assessed in follow up examinations to be compared with CT follow up. Results: Lung US score ranged from -2 to 17 with mean value of 8.75 ± 3.88 for improving patients, while worsening patients showed lung US score of -11 to -20 with mean value of -10.08 ± 6.95 with high statistical significance (p<0.001).The best cutoff value of lung US score changes for detecting good response to antibiotic was 2.5, detected using area under the curve (AUC) (p<0.001). Ultrasound score on day seven showed excellent sensitivity and specificity of 91.89% and 92.31% respectively when compared to CT with PPV of 97.14% and NPV 80% and accuracy 92% with strong statistical significance (p<0.001). Air bronchogram showed sensitivity of 61.5% and specificity of 89.1% and with PPV of 66.67% and NPV of 86.84% and accuracy of 82% and moderate agreement (0.52) with CT while B-lines were significant for assessing lung reaeration with sensitivity of 69.2% and specificity of 67.5% and accuracy of 68% but with fair (0.31) agreement with CT (p<0.027) in detecting parenchymal lung recovery. Conclusion: Lung US is a reasonable bedside method for quantifying parenchymal lung recovery in patients with pneumonia who are successfully treated with antibiotics.

Evaluation of Antibiotic Tolerance in Pseudomonas aeruginosa for Aminoglycosides and its Prediction of Resistance Development Through In-silico Transcriptomic Analysis

Pseudomonas aeruginosa causes severe life-threatening infections and are difficult to treat. The lack of antibiotic response in P. aeruginosa is due to adaptive resistance, which prevents the entry of antibiotics into cytosol of the cell. Among different groups of antibiotics, aminoglycosides show superior antibiotic response and are used as a parental antibiotic for treatment. This study aims to determine the kinetics of adaptive resistance development and gene expression changes in P. aeruginosa exposed to amikacin, gentamicin, and tobramycin. In vitro antibiotic exposure to P. aeruginosa was performed and optical density of the cells were monitored for every 12 hours until 72 hours. The growth pattern plotted in graph represents the kinetics of adaptive resistance developed to respective antibiotics. The transcriptomic profile of P. aeruginosa PA14 to post exposed antibiotic was taken from Gene Expression Omnibus (GEO), NCBI. The gene expressions of two datasets were analyzed by case-control study. Tobramycin exposed P. aeruginosa failed to develop adaptive resistance in 0.5ug/mL, 1ug/mL and 1.5ug/mL of its MIC. Whereas, amikacin and gentamicin treated P. aeruginosa developed tolerance in the inhibitory concentrations of the antibiotics. This depicts the superior in vitro response of tobramycin over the gentamicin and amikacin. Furthermore, tobramycin treated P. aeruginosa microarray analysis resulted in low expression of catalytic enzyme 16s rRNA Methyltransferase E, B & L, alginate biosynthesis genes and several proteins of Type 2 Secretory System (T2SS) and Type 3 Secretory System (T3SS). The Differentially Expressed Genes (DEGs) of alginate biosynthesis, and RNA Methyltransferases suggests increased antibiotic response and low probability of developing resistance. The use of tobramycin as a parental antibiotic with its synergistic combination might combat P. aeruginosa with increased response.

Life in a Droplet: Microbial Ecology in Microscopic Surface Wetness

While many natural and artificial surfaces may appear dry, they are in fact covered by thin liquid films and microdroplets invisible to the naked eye known as microscopic surface wetness (MSW). Central to the formation and the retention of MSW are the deliquescent properties of hygroscopic salts that prevent complete drying of wet surfaces or that drive the absorption of water until dissolution when the relative humidity is above a salt-specific level. As salts are ubiquitous, MSW occurs in many microbial habitats, such as soil, rocks, plant leaf, and root surfaces, the built environment, and human and animal skin. While key properties of MSW, including very high salinity and segregation into droplets, greatly affect microbial life therein, it has been scarcely studied, and systematic studies are only in their beginnings. Based on recent findings, we propose that the harsh micro-environment that MSW imposes, which is very different from bulk liquid, affects key aspects of bacterial ecology including survival traits, antibiotic response, competition, motility, communication, and exchange of genetic material. Further research is required to uncover the fundamental principles that govern microbial life and ecology in MSW. Such research will require multidisciplinary science cutting across biology, physics, and chemistry, while incorporating approaches from microbiology, genomics, microscopy, and computational modeling. The results of such research will be critical to understand microbial ecology in vast terrestrial habitats, affecting global biogeochemical cycles, as well as plant, animal, and human health.