Diagnosis Of Respiratory Infections Research Articles

Impact of antipyretics on acute asthma exacerbation during respiratory infection—A nationwide population-based study

Antipyretics are frequently used in pediatric practice. Both acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to increase the risk of asthma exacerbation. The study investigated antipyretic use during respiratory infection in children and analyzed the risk of acetaminophen and NSAID for severe asthma exacerbation (AE) in asthmatic children in Taiwan. We used the data from the National Health Insurance Research Database in 2005. There were 27,095 pediatric asthmatic patients having at least one respiratory infection episode, and 27,095 age- and sex-matched non-asthmatic children with respiratory infection served as controls. These patients were divided into groups with acetaminophen use, NSAID cyclooxygenase-1 (COX-1) use, and no antipyretic use. The rate of AE occurrence within the first 7 days after respiratory infection diagnosis was compared among the groups. During a single episode of respiratory infection, asthmatic patients used fewer antipyretics than controls (48.51% vs. 55.50%, p<0.001). No difference was observed in the risk of AE occurrence within 7 days after respiratory infection between antipyretic users and antipyretic nonusers (22/13,144 [0.167%] vs. 12/13,951 [0.086%], p=0.058). Compared with asthmatic children using acetaminophen, those using no antipyretic and COX-1 have lower risks for AE (OR: 0.26, 95% CI: 0.12-0.54, p<0.001; and OR: 0.14, 95% CI: 0.03-0.61, p=0.009). In asthmatic children, the rate of AE after a single respiratory infection episode was around 0.144%. The risk of AE was higher in those who took acetaminophen.

Multiple Respiratory Syncytial Virus Introductions Into a Neonatal Intensive Care Unit.

Outbreaks of respiratory syncytial virus (RSV) in neonatal intensive care units (NICUs) are of concern because of the risk of severe disease in young infants. We describe an outbreak of RSV in a NICU and use whole genome sequencing (WGS) to better understand the relatedness of viruses among patients. An investigation was conducted to identify patients and describe their clinical course. Infection control measures were implemented to prevent further spread. Respiratory specimens from outbreak-related patients and the community were tested using WGS. Phylogenetic trees were constructed to understand relatedness of the viruses. Seven patients developed respiratory symptoms within an 11-day span in December 2017 and were diagnosed with RSV; 6 patients (86%) were preterm and 1 had chronic lung disease. Three patients required additional respiratory support after symptom onset, and none died. Six of 7 patients were part of the same cluster based on > 99.99% nucleotide agreement with each other and 3 unique single-nucleotide polymorphisms were identified in viruses sequenced from those patients. The seventh patient was admitted from the community with respiratory symptoms and had a genetically distinct virus that was not related to the other 6. Implementation of enhanced infection control measures likely limited the spread. Using WGS, we found 2 distinct introductions of RSV into a NICU, highlighting the risk of healthcare-associated infections during RSV season. Early recognition and infection control measures likely limited spread, emphasizing the importance of considering RSV in the differential diagnosis of respiratory infections in healthcare settings.

Diagnostic value of pentraxin 3 in respiratory tract infections: A meta-analysis.

Background:Pentraxin 3 is an acute inflammatory protein of the long pentraxin subfamily. A meta-analysis was performed to assess diagnostic accuracy of pentraxin 3 for respiratory tract infections.Methods:We identify studies examining diagnostic value of pentraxin 3 for respiratory tract infections by searching Pubmed, Web of Knowledge, and Cochrane Library. The sensitivity, specificity, negative likelihood ratio (LR), positive LR, and diagnostic odds ratio were pooled. The area under the summary receiver operator characteristic (SROC) curve and Q point value (Q∗) were calculated.Results:A total of 8 studies with 961 individuals were eligible for this meta-analysis. The pooled sensitivity of pentraxin 3 in diagnosis of respiratory tract infections was 0.78, the pooled specificity was 0.73, the area under the SROC curve was 0.84, and the Q∗ was 0.77. The area under the SROC curve of serum and bronchoalveolar lavage fluid (BALF) pentraxin 3 was 0.85 and 0.89, respectively. Meta-regression analysis revealed that cutoff value was the source of heterogeneity among the included studies. The Deek funnel plot test suggested no evidence of publication bias. Subgroup analyses showed that the area under the SROC curve of pentraxin 3 in diagnosis of ventilator-associated pneumonia (VAP) was 0.89.Conclusion:Pentraxin 3 has a moderate accuracy for diagnosing respiratory tract infections and VAP. The overall diagnostic value of BALF level of pentraxin 3 is superior to its serum concentration.

Viral Respiratory Infection, a Risk in Pediatric Cardiac Surgery: A Propensity-Matched Analysis.

1) To describe the postoperative course and outcomes of cardiac surgery in children with perioperative viral respiratory infection, 2) to evaluate optimal surgical timing for preoperative viral respiratory infection patients, and 3) to define risk stratification. Retrospective study of children undergoing cardiac surgery. Children were tested using a multiplex polymerase chain reaction (respiratory virus polymerase chain reaction) panel capturing seven respiratory viruses. Respiratory virus polymerase chain reaction testing was routinely performed in patients under 2 years old. Those with negative results yet highly suspected of viral respiratory infection after surgeries would be tested again. A pediatric cardiac surgical ICU of pediatric cardiac surgery department at Fuwai Hospital. Children admitted between January 1, 2014, and December 31, 2016, to perform respiratory virus polymerase chain reaction testing and cardiac surgery were included. None. A total of 2,831 patients had respiratory virus polymerase chain reaction testing, and viruses were detected in 91 patients (3.2%), including 35 preoperative and 56 postoperative. Of the 35 preoperative viral respiratory infection patients, there were 29 viral respiratory infection-resolved (patients for whom surgery was postponed until resolution of viral respiratory infection symptoms and negative respiratory virus polymerase chain reaction) and six viral respiratory infection-unresolved (who underwent cardiac surgery before resolution of symptoms and clearance of carriage) patients. Furthermore, there were seven deaths, including one in the preoperative viral respiratory infection-unresolved group and six in the postoperative viral respiratory infection group. A propensity score matching was performed to correct the selection bias and identify the comparable patient groups. Compared to their matched nonviral respiratory infection patients, viral respiratory infection-resolved patients had similar duration of mechanical ventilation and length of stay, while viral respiratory infection-unresolved patients had longer durations of postoperative mechanical ventilation (p = 0.033), PICU (p = 0.028) and hospital length of stay (p = 0.010), and postoperative viral respiratory infection patients had significantly greater duration of postoperative recovery (p < 0.001) and higher mortality (p < 0.001). Earlier diagnosis of postoperative viral respiratory infection was associated with longer mechanical ventilation duration (r = 0.422; p < 0.001). Palliative cardiac surgery was the only variable significantly associated with mortality in multivariate analysis (odds ratio, 12.0; 95% CI, 1.6-87.5; p = 0.014). The preoperative-unresolved and postoperative viral respiratory infection were associated with prolonged postoperative recovery, increased severity, and mortality in children with cardiac surgeries. Our results suggested the optimal surgical timing may be after the resolution of viral respiratory infection symptoms and carriage unless the perceived benefits of early surgery outweigh the risk of death, prolonged ventilation, and PICU length of stay. Palliative surgeries were associated with increasing mortality.

Calprotectin, a new biomarker for diagnosis of acute respiratory infections

Respiratory tract infections require early diagnosis and adequate treatment. With the antibiotic overuse and increment in antibiotic resistance there is an increased need to accurately distinguish between bacterial and viral infections. We investigated the diagnostic performance of calprotectin in respiratory tract infections and compared it with the performance of heparin binding protein (HBP) and procalcitonin (PCT). Biomarkers were analyzed in patients with viral respiratory infections and patients with bacterial pneumonia, mycoplasma pneumonia and streptococcal tonsillitis (n = 135). Results were compared with values obtained from 144 healthy controls. All biomarkers were elevated in bacterial and viral infections compared to healthy controls. Calprotectin was significantly increased in patients with bacterial infections; bacterial pneumonia, mycoplasma pneumonia and streptococcal tonsillitis compared with viral infections. PCT was significantly elevated in patients with bacterial pneumonia compared to viral infections but not in streptococcal tonsillitis or mycoplasma caused infections. HBP was not able to distinguish between bacterial and viral causes of infections. The overall clinical performance of calprotectin in the distinction between bacterial and viral respiratory infections, including mycoplasma was greater than performance of PCT and HBP. Rapid determination of calprotectin may improve the management of respiratory tract infections and allow more precise diagnosis and selective use of antibiotics.

Determination of serum amyloid A, haptoglobin and hepcidin levels in calves with endemic viral pneumonia

The aim of this study was to investigate serum amyloid A, haptoglobin and hepcidin levels in respiratory infections caused by various viral agents in calves. Pneumonia is an infectious or non-infectious disease affecting the lungs of all animals, and during the inflammation, blood levels of acute phase proteins increase rapidly. Hepcidin is a hormone that has many functions and is known as type II acute phase reactant. The blood samples were collected from a total of 20 calves to form the study group. The control group consisted of 10 healthy animals. Sera were analyzed with ELISA for antigen detection. According to the results, Bovine herpesvirus type-1 (BHV-1) was positive in 3 calves, Bovine viral diarrhea virus (BVDV) was positive in 3 calves, Bovine respiratory syncytial virus (BRSV) was positive in 1 calf, and Bovine parainfluenza virus type 3 (BPI3) was positive in 1 calf. Adenovirus infection was detected in 5 animals together with other viruses. Mixed infections were observed in 12 calves. Haptoglobin, serum amyloid A and hepcidin values were measured in sera. According to the results, statistically significant differences were observed between the two groups for the haptoglobin (P&amp;lt;0.01), serum amyloid A (P&amp;lt;0.05) and hepcidin (P&amp;lt;0.05). It was concluded that these parameters can be used to support the diagnosis of respiratory infections of the calves.

Challenges in the Diagnosis and Management of Bacterial Lung Infections in Solid Organ Recipients: A Narrative Review.

Respiratory infections pose a significant threat to the success of solid organ transplantation, and the diagnosis and management of these infections are challenging. The current narrative review addressed some of these challenges, based on evidence from the literature published in the last 20 years. Specifically, we focused our attention on (i) the obstacles to an etiologic diagnosis of respiratory infections among solid organ transplant recipients, (ii) the management of bacterial respiratory infections in an era characterized by increased antimicrobial resistance, and (iii) the development of antimicrobial stewardship programs dedicated to solid organ transplant recipients.

Diagnosis and treatment recommendations for pediatric respiratory infection caused by the 2019 novel coronavirus.

Since December 2019, an epidemic caused by novel coronavirus (2019-nCoV) infection has occurred unexpectedly in China. As of 8 pm, 31 January 2020, more than 20 pediatric cases have been reported in China. Of these cases, ten patients were identified in Zhejiang Province, with an age of onset ranging from 112 days to 17 years. Following the latest National recommendations for diagnosis and treatment of pneumonia caused by 2019-nCoV (the 4th edition) and current status of clinical practice in Zhejiang Province, recommendations for the diagnosis and treatment of respiratory infection caused by 2019-nCoV for children were drafted by the National Clinical Research Center for Child Health, the National Children’s Regional Medical Center, Children’s Hospital, Zhejiang University School of Medicine to further standardize the protocol for diagnosis and treatment of respiratory infection in children caused by 2019-nCoV.

Diagnosis of severe respiratory infections in immunocompromised patients.

An increasing number of critically ill patients are immunocompromised. Acute hypoxemic respiratory failure (ARF), chiefly due to pulmonary infection, is the leading reason for ICU admission. Identifying the cause of ARF increases the chances of survival, but may be extremely challenging, as the underlying disease, treatments, and infection combine to create complex clinical pictures. In addition, there may be more than one infectious agent, and the pulmonary manifestations may be related to both infectious and non-infectious insults. Clinically or microbiologically documented bacterial pneumonia accounts for one-third of cases of ARF in immunocompromised patients. Early antibiotic therapy is recommended but decreases the chances of identifying the causative organism(s) to about 50%. Viruses are the second most common cause of severe respiratory infections. Positive tests for a virus in respiratory samples do not necessarily indicate a role for the virus in the current acute illness. Invasive fungal infections (Aspergillus, Mucorales, and Pneumocystis jirovecii) account for about 15% of severe respiratory infections, whereas parasites rarely cause severe acute infections in immunocompromised patients. This review focuses on the diagnosis of severe respiratory infections in immunocompromised patients. Special attention is given to newly validated diagnostic tests designed to be used on non-invasive samples or bronchoalveolar lavage fluid and capable of increasing the likelihood of an early etiological diagnosis.Electronic supplementary materialThe online version of this article (10.1007/s00134-019-05906-5) contains supplementary material, which is available to authorized users.

Occupying 'in-hospitable' spaces: Parental/primary-caregiver perceptions of the impact of repeated hospitalisation in children under two years of age.

The experience of having a child hospitalised is stressful and disrupts families in myriad ways; however, the experiences of parents/caregivers who encounter repeated admissions of a child with acute lower respiratory infections are under-researched. This project aims to explore these experiences, from a qualitative perspective, using the philosophical tenets of reflective lifeworld research. The research included 14 face-to-face interviews with parents, grandparents, or primary caregivers, of children who, whilst under two years of age, were admitted to hospital multiple times with a lower respiratory infection diagnosis. Many of the participants were from Māori or Samoan ethnic backgrounds. The findings of this single site study revealed that these parents/caregivers' experiences were characterised by feelings of powerlessness, offering descriptions of hospitals as harsh and difficult places to reside, they are ‘in-hospitable’. The findings suggest that repeated hospitalisations created a cycle of stressful experiences that impacted both familial relationships and interactions with society. This study draws attention to this previously obscured population group, and calls health care practitioners and policy advisors to engage differently over issues involving families in similar positions.

Role of hematological parameters in the diagnosis of influenza virus infection in patients with respiratory tract infection symptoms.

BackgroundThe differential diagnoses of patients hospitalized for respiratory infections due to influenza virus vs other pathogens are challenging. Our study investigated whether hematological parameters such as neutrophil (N), lymphocyte (L), platelet (PLT), and neutrophil‐to‐lymphocyte ratio (NLR) contributed in diagnosing influenza virus infections and in discriminating other respiratory infections.MethodsWe retrospectively analyzed the laboratory characteristics of 307 patients with respiratory infections caused by influenza/non‐influenza virus and bacteria. The diagnostic abilities of hematological indexes were evaluated in the patients compared with 100 healthy people.ResultsThe hematological parameters in patients with influenza virus infection were dramatically altered compared with those in the controls. Additionally, among the systemic inflammatory markers, the sensitivity of NLR for influenza detection was higher than that of N and L. PLT was significantly lower in influenza virus‐positive infection than in influenza virus‐negative infection. Moreover, when patients with influenza virus infection were cured, PLT returned to a normal level. The red blood cell (RBC) and hemoglobin (Hb) levels of influenza virus infection were higher than those of bacterial infection. Compared with traditional N and L, NLR and platelet‐to‐neutrophil (PNR) showed greater significance between influenza virus and bacterial infection (P < .01).ConclusionNeutrophil‐to‐lymphocyte ratio with high sensitivity is a preferable diagnostic tool to screen influenza virus‐infected patients than N and L. PLT accounts in the differential diagnoses of respiratory infections due to influenza virus and other pathogens among patients. In addition, RBC, Hb, NLR, and PNR can significantly differentiate between influenza virus infections and bacterial infections.

Diagnosis and Application of Serum Procalcitonin in Lower Respiratory Tract Infections

The role of serum procalcitonin in early diagnosis of lower respiratory tract bacterial infections is tested and studied. The prognosis of ventilator-associated pneumonia group and nonventilator-associated pneumonia group were compared. There was no significant difference between ventilator-associated pneumonia group and nonventilator-associated pneumonia group before mechanical ventilation. After mechanical ventilation, procalcitonin, C-reactive protein and white blood cells in ventilator-associated pneumonia group were significantly higher than those in nonventilator-associated pneumonia group (t=1.62-2.31, P<0.05) and the body temperature was also elevated, which is not significant. The sensitivity and specificity of procalcitonin in diagnosing ventilator-associated pneumonia were 86 and 91 %, respectively. Procalcitonin level in Gram negative bacteria group was significantly higher than that in Gram positive bacteria group (t=1.99, P<0.05). Immunofluorescence quantitative assay was used to detect respiratory infection patients and the treatment of some patients was monitored. At the same time, white blood cells and C-reactive protein were compared with procalcitonin. The sensitivity and specificity of procalcitonin in bacterial infections of respiratory system are obviously higher than those of traditional C-reactive protein and white blood cells. It can be used for early diagnosis of bacterial infections quickly. This study provided important clinical evidence in judging the severity and prognosis of infection and is helpful for rational use of antibiotics.

Laboratory Diagnosis of Severe Acute Respiratory Syndrome-related Coronavirus-2 Infection

Laboratory Diagnosis of Severe Acute Respiratory Syndrome-related Coronavirus-2 Infection

Incidence and Distribution of Respiratory Microorganisms Causing Acute Respiratory Infections at the University Hospital of Korea.

Acute respiratory infection caused by respiratory microorganisms including various kinds of viruses and bacteria is the most common infectious disease. When managing patients, it is crucial to detect these microorganisms rapidly and monitor their occurrence and tendency. Recently, the methods of detecting them have been implemented by molecular diagnostics. The authors intended to investigate their incidence and distribution and identify the significance of the molecular diagnosis for their detection. The retrospective study was conducted to investigate the incidence and distribution of respiratory microorganisms according to the age, gender, month, season, and the detection method and to analyze their co-infections from July 2016 to December 2019. In addition, the four types of turn-around time (TAT) for each detec-tion method were also analyzed. The overall incidence for at least one respiratory microorganism was 23.1% (3,645/15,808). The highest incidence was identified in age group 2 (1 - 3 months), 38.5%. The incidence rates by multiplex PCR using Anyplex and Allplex, FilmArray method, and influenza virus (flu) antigen detection test were 44.2% (718/1,625), 63.1% (1,198/1,899), and 14.1% (1,729/12,284), respectively. The overall incidence between male and female patients showed no statistically significant difference (p = 0.980), except for the flu antigen detection test (p = 0.000). Influenza A viruses (flu A) accounted for the highest percentage (34.9%), followed by rhinovirus/enterovirus (20.5%), RSV (12.8%), flu B (8.3%), and adenovirus (7.6%). These microorganisms showed characteristic distribution patterns according to season and month. Flu A and flu B predominated in winter and accounted for an increasing proportion as age increased according to the age groups. The overall co-infection rate was 22.5% (432/1,916). The average TATs of the FilmArray method were significantly much faster than multiplex PCR using Anyplex and Allplex (p = 0.000). The information on the incidence and distribution of respiratory microorganisms and their expeditious detection are considered critical to the management of the elderly, immunocompromised patients, and children. The rapid molecular-based diagnosis of respiratory infections would be beneficial in medical decision and prevention of their propagation.

Stacked Ensemble Improvement of the Lower Respiratory Tract Infection Diagnoses in Peadiatric

Lower Respiratory Tract Infections (LRTIs) are the second and third causes of pediatric patients' death in Nigeria and the United States of America. It is observed from several reviewed literature that the LRTIs accounted for more than a million children morbidity and mortality yearly due to lack of prompt diagnosis or no diagnosis due to a shortage of medical experts and medical facilities in our localities. Intense research is ongoing on applying machine learning (ML) to its clinical diagnosis and reducing its spread in pediatric patients. In this research, K-Nearest Neighbor (KNN), C4.5 Decision Tree, and Naive Bayes' ML algorithms were used to develop three base diagnosis models with Correlation, consistency, and information gain selected feature of the LRTI dataset, Multiple Model Trees (MMT) Meta algorithm is used to combine and improve the diagnoses of all the base models using stacked ensemble. The preliminary diagnosis findings using base models have established that the information gained feature extraction method performed much better than the other two. It, therefore, suffix that the results from this should be used for further processing. All the models built with the reduced feature set recorded improved diagnoses accuracy more than the model built with the whole feature set. The MMT stacked ensemble models recorded an improvement on the diagnosis of LRTIs in Peadiatric, it recorded the highest diagnostic accuracies improvement of 12.80%, 13.52%, and 12.37%, and lowest diagnostic accuracies improvement of 6.37%, 5.22%, and 6.09% with the MMT stacked ensemble models of the Consistency, the Correlation, and the information gain reduced selected feature set respectively. These experimental results show the potential for this approach to deliver a reliable and improved diagnosis of LRTIs. It is recommended to be used to diagnose LRTIs in primary health care centers to reduce its mortality rate.

Caracterización del uso inapropiado de antibióticos en faringoamigdalitis según los criterios de McIsaac

Objetivo: Describir el uso irracional de antibióticos en base a criterios de McIsaac (criterios de Centor modificados por McIsaac), en una unidad de salud de primer nivel de atención. Métodos: Se realizó un estudio descriptivo transversal con los registros de pacientes de 3 a 19 años atendidos en el servicio de emergencia (246), con los diagnósticos de faringitis aguda, amigdalitis aguda, e infecciones respiratorias superiores agudas de múltiples sitios y sin especificar. Se estableció como prescripción inadecuada si el facultativo indicó antibióticos con un puntaje menor o igual a 1 sobre 5 puntos o si no prescribió antibióticos con puntaje mayor o 4 sobre 5 puntos. Resultados: Se estimó 24,29% de uso inadecuado de antibióticos de los registros de emergencia. Se prescribió antibióticos en 160 pacientes, de los cuales se encontró que, amoxicilina fue el más utilizado (61,87%); seguido de benzilpenicilina benzatina (28,12%) y en tercer lugar macrólidos (8,12%). Conclusión: En la unidad de primer nivel analizada se encontró que el uso inadecuado de antibióticos es superior a la prevalecía estimada de faringoamigdalitis estreptocócica para el grupo de edad estudiado. Por esto, es imperativo que se tomen las medidas necesarias a nivel institucional y comunitario para lograr su reducción y evitar las complicaciones que se derivan de esta.

Acute respiratory viral infections in children

Acute respiratory viral infections in children lead in the structure of child morbidity. The defeat of the upper respiratory tract accompanied by fever and impaired general condition, the main symptoms of acute respiratory viral infections. Diagnosis of most acute respiratory viral infections is based on the assessment of clinical manifestations and does not require the use of specific laboratory and instrumental methods. Modern approaches to treatment are timely and adequate symptomatic therapy.

Acute respiratory viral diseases: modern approaches to the diagnosis and treatment

Acute respiratory viral infections (ARVI) are one of the most common reasons patients seek ambulatory care. ARVIs can be caused by more than 200 strains of viruses, among which rhinoviruses remain a leading cause. The article discusses the epidemiological characteristics of ARVI and the economic damage caused by high incidence to the community. The clinical presentation of ARVI is nearly always accompanied by a combination of symptoms such as nasal discharge, nasal congestion, sore throat and cough combined with muscle pain, weakness, fatigue, headache and decreased appetite. Diagnosis of acute respiratory viral infections must be differentiated from influenza, allergic rhinitis, streptococcal tonsillitis, sinusitis and otitis media. Practicing hand hygiene is an effective way to prevent infections. The article discusses possibilities and effectiveness of concomitant adjuvant therapy, including the use of decongestants, topical glucocorticosteroids, nasal irrigation solutions, non-steroidal anti-inflammatory drugs, paracetamol and antitussive drugs. Antibacterial therapy does not have a positive effect on the course of ARVI. A clinical case describing the management of a patient with ARVI is provided.

Are Community Acquired Respiratory Viral Infections an Underestimated Burden in Hematology Patients?

Despite a plethora of studies demonstrating significant morbidity and mortality due to community-acquired respiratory viral (CRV) infections in intensively treated hematology patients, and despite the availability of evidence-based guidelines for the diagnosis and management of respiratory viral infections in this setting, there is no uniform inclusion of respiratory viral infection management in the clinical hematology routine. Nevertheless, timely diagnosis and systematic management of CRV infections in intensively treated hematology patients has a demonstrated potential to significantly improve outcome. We have briefly summarized the recently published data on CRV infection epidemiology, as well as guidelines on the diagnosis and management of CRV infections in patients intensively treated for hematological malignancies. We have also assessed available treatment options, as well as mentioned novel agents currently in development.

162. Identifying Determinants of Therapeutic Switch to Linezolid among Patients with Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

BackgroundIn order to target future randomized controlled trials (RCT) of treatment of methicillin-resistant S aureus bloodstream infections (MRSA BSI), it will be important to understand the drivers of antibiotic selection. We aimed to determine factors associated with switching from vancomycin to inpatient linezolid administration during the management of MRSA BSI.MethodsThis retrospective cohort included all patients admitted to Veteran Affairs hospitals from 2007 to 2014 and had received vancomycin for MRSA BSI. Patients were considered to have switched to linezolid from vancomycin if they received at least 2 consecutive days of inpatient treatment and were not on concurrent vancomycin treatment. Cox proportional hazards models were used to identify factors that were associated with switch within 14 days and 30 days. Median with interquartile range (IQR), hazard ratio (HR) and 95% confidence intervals were reported.ResultsAmong 7289 patients diagnosed with MRSA BSI during their index admission, 474 (6.5%) switched to linezolid during the admission. The median inpatient duration of vancomycin treatment among all patients was 13 days (IQR: 5–34) and among patients who switched was 16 days (IQR: 6–52). The median inpatient duration of linezolid treatment was 5 days (IQR: 1–13 days). Patients who switched to linezolid were more likely to have a MRSA isolate with MIC >=2 µg/mL (6.8% vs. 4.9%), diagnosis of respiratory tract infection (36.7% vs. 32.9%), or be obese (16.5% vs. 13.6%) than those who continued on vancomycin (P < 0.10). In risk-adjustment models, presence of a respiratory tract infection diagnosis was associated with greater likelihood of being switched to linezolid within 14- and 30-days (HR=1.29, 95% CI 1.01–1.64; HR=1.32, 95% CI 1.06–1.65).ConclusionLess than 10% of patients initially treated with vancomycin for MRSA BSI were switched to linezolid in this real-world study. A diagnosis of respiratory tract infection was a major determinant of switching to linezolid. It is important to identify potential subsets of MRSA BSI patients so that future comparative effectiveness RCTs can be targeted to indications with clinical equipoise in real-world practice settings.Disclosures All authors: No reported disclosures.