Risk factors for bacteremic pneumonia and mortality (28-day mortality) in patients with Acinetobacter baumannii bacteremia.

BACKGROUND: Patients infected with Acinetobacter baumannii (AB) bacteremia in hospital have high morbidity and mortality. We analyzed the clinical characteristics of pneumonia and nonpneumonia-related AB bloodstream infections (AB BSIs) and explored the possible independent risk factors for the incidence and prognosis of pneumonia-related AB BSIs. METHODS: A retrospective monocentric observational study was performed. All 117 episodes of hospital-acquired AB bacteremia sorted into groups of pneumonia-related AB BSIs (n = 45) and nonpneumonia-related AB BSIs (n = 72) were eligible. Univariate/multivariate logistic regression analysis was used to explore the independent risk factors. The primary outcome was the antibiotic susceptibility in vitro of pneumonia-related AB BSIs group. The secondary outcome was the independent risk factor for the pneumonia-related AB BSIs group. RESULTS: Among 117 patients with AB BSIs, the pneumonia-related group had a greater risk of multidrug resistant A. baumannii (MDRAB) infection (84.44%) and carbapenem-resistant A. baumannii (CRAB) infection (80%). Polymyxin, minocycline and amikacin had relatively high susceptibility rates (> 80%) in the nonpneumonia-related group. However, in the pneumonia-related group, only polymyxin had a drug susceptibility rate of over 80%. Univariate analysis showed that survival time (day), CRAB, MDRAB, length of hospital stay prior to culture, length of ICU stay prior to culture, immunocompromised status, antibiotics used prior to culture (n > = 3 types), endotracheal tube, fiberoptic bronchoscopy, PITT, SOFA and invasive interventions (n > = 3 types) were associated with pneumonia-related AB bacteremia. The multivariate logistic regression analysis revealed that recent surgery (within 1 mo) [P = 0.043; 0.306 (0.098-0.962)] and invasive interventions (n > = 3 types) [P = 0.021; 0.072 (0.008-0.671)] were independent risk factors related to pneumonia-related AB bacteremia. Multivariate logistic regression analysis revealed that length of ICU stay prior to culture [P = 0.009; 0.959 (0.930-0.990)] and recent surgery (within 1 mo) [P = 0.004; 0.260 (0.105-0.646)] were independent risk factors for mortality in patients with pneumonia-related AB bacteremia. The Kaplan‒Meier curve and the timing test showed that patients with pneumonia-related AB bacteremia had shorter survival time compared to those with nonpneumonia-related AB bacteremia. CONCLUSIONS: Our study found that A. baumannii had a high rate of antibiotic resistance in vitro in the pneumonia-related bacteremia group, and was only sensitive to polymyxin. Recent surgery was a significantly independent predictor in patients with pneumonia-related AB bacteremia.

The prevalence of pneumothorax in human immunodeficiency virus patients. A single center study.

OBJECTIVES: To assess the prevalence, risk factors, and associated complications of pneumothorax that are present in patients with human immunodeficiency virus (HIV) at our institution and to provide an updated local study addressing the association between pneumothorax and HIV. METHODS: This retrospective cohort study examined 161 patients who were admitted with a diagnosis of HIV from June 2017 to May 2022. They were divided into 2 groups depending on the presence of pneumothorax during their stay. Multiple variables were studied, including age, gender, tuberculosis infection, pneumocystis jiroveci pneumonia (PJP)infection, bacterial pneumonia, and pneumothorax type and treatment course. RESULTS: There were 11 patients diagnosed with pneumothorax (prevalence rate: 6.8%). Bacterial lung infection was found in 9 (81.8%) of these patients, while fungal infection was found in 6 (54.5%) (p<0.001, 0.010). The MTB was found in 3 (27.3%) patients (p=0.728), while none were infected with PJP. Intercostal tube insertion was attempted in 9 (81.8%) patients, the mean duration of tube stay was 39.3±30.7 days, and the mortality rate was 72.7% (p=0.007). CONCLUSION: Pneumothorax in patients with HIV is a manifestation of the progression of the disease and its poor outcome. It has a complicated treatment course and a high mortality rate.

Radiographic findings of adenoviral pneumonia in children.

OBJECTIVE: Adenovirus pneumonia is a common cause of community-acquired pneumonia in children and can mimic bacterial pneumonia, but there are few publications on its radiographic features. This study has evaluated the chest radiography findings of community-acquired adenovirus pneumonia in children. The frequency of radiological findings mimicking bacterial pneumonia was investigated. The clinical features of patients with adenovirus pneumonia possessing radiological findings mimicking bacterial pneumonia were also evaluated. MATERIALS AND METHODS: The chest radiographs of patients diagnosed with adenovirus pneumonia were retrospectively reviewed. The chest radiographs were interpreted independently by a pediatric infectious disease specialist and a pediatric radiologist. Chest radiography findings mimicking bacterial pneumonia (bacterial-like) were specified as consolidation +/- pleural effusion. Other findings on chest radiography or a completely normal chest X-ray were specified as findings that were compatible with "typical viral pneumonia". RESULTS: A total of 1407 patients were positive for adenovirus with respiratory multiplex PCR. The 219 patients who met the study criteria were included in the study. Chest radiographs were normal in 58 (26.5 %) patients. The chest radiograph findings mimicked bacterial pneumonia in 41 (18.7 %) patients. CONCLUSION: Adenovirus pneumonia occurs predominantly in children aged five years and younger, as with other viral pneumonias. The radiographic findings in adenovirus pneumonia are predominantly those seen in viral pneumonia. Increasing age and positivity for only adenovirus without other viruses on respiratory multiplex PCR were associated with the chest radiograph being more likely to be "bacterial-like". Adenovirus may lead to lobar/segmental consolidation at a rate that is not very rare.

Zinc deficiency enhances sensitivity to influenza A associated bacterial pneumonia in mice.

Although zinc deficiency (secondary to malnutrition) has long been considered an important contributor to morbidity and mortality of infectious disease (e.g. diarrhea disorders), epidemiologic data (including randomized controlled trials with supplemental zinc) for such a role in lower respiratory tract infection are somewhat ambiguous. In the current study, we provide the first preclinical evidence demonstrating that although diet-induced acute zinc deficiency (Zn-D: ~50% decrease) did not worsen infection induced by either influenza A (H1N1) or methicillin-resistant staph aureus (MRSA), Zn-D mice were sensitive to the injurious effects of superinfection of H1N1 with MRSA. Although the mechanism underlying the sensitivity of ZnD mice to combined H1N1/MRSA infection is unclear, it was noteworthy that this combination exacerbated lung injury as shown by lung epithelial injury markers (increased BAL protein) and decreased genes related to epithelial integrity in Zn-D mice (surfactant protein C and secretoglobins family 1A member 1). As bacterial pneumonia accounts for 25%-50% of morbidity and mortality from influenza A infection, zinc deficiency may be an important pathology component of respiratory tract infections.

Acute glomerulonephritis with concurrent suspected bacterial pneumonia - is it the tip of the iceberg?

BACKGROUND: Post infectious glomerulonephritis is the most common glomerulopathy in children, occurring several weeks after nephritogenic streptococcal throat or skin infection. Reports of acute glomerulonephritis (AGN) occurring during active bacterial pneumonia in children are rare. The aim of this study was to evaluate the incidence of AGN concurrent with bacterial pneumonia in children. METHODS: We reviewed records of all children admitted with a diagnosis of pneumonia to the pediatric department in a single tertiary medical center between January 2015 and April 2023. Patients with bacterial pneumonia and concurrent glomerulonephritis were included. RESULTS: Eleven (0.98%) of 1,123 patients with bacterial pneumonia had concurrent AGN. All were males with a median age of 2.7 years (range 1-13). Mean time from bacterial pneumonia onset to acute glomerulonephritis symptoms was 2.7 ± 1.5 days. Five (45%) patients had evidence of pneumococcal infection. Hypertension was found in 10 (91%) patients. Mean trough eGFR was 43.5 ± 21.4 ml/min/1.73 m2 (range 11-73). Ten patients (91%) had low C3 levels. Median urinary protein-to-creatinine ratio was 2.5 mg/mg (IQR 2.15-14.75). All patients fully recovered. Microscopic hematuria was the last finding to normalize after a median of 29.5 days (IQR 17.25-38). CONCLUSION: AGN during bacterial pneumonia may be more frequent than previously recognized. Kidney prognosis was excellent in all patients. Prospective studies are needed to evaluate the impact of this condition.

The causal relationship between bacterial pneumonia and diabetes: a two-sample mendelian randomization study.

BACKGROUND: Previous observational studies have established the high prevalence of bacterial pneumonia in diabetic patients, which in turn leads to increased mortality. However, the presence of a causal connection between bacterial pneumonia and diabetes remains unobserved. METHODS: We chose genome-wide significant (Ρ < 1 × 10-5 and Ρ < 1 × 10-6) and independent (r2 < 0.001) single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs) to proceed a bidirectional two-sample MR study. The extracted SNPs explored the relationship between bacterial pneumonia and diabetes by Inverse variance weighted (IVW), MR-Egger, and weighted median methods. In addition, we conducted the Heterogeneity test, the Pleiotropy test, MR-presso and the Leave-one-out (LOO) sensitivity test to validate the reliability of results. RESULTS: In an MR study with bacterial pneumonia as an exposure factor, four different types of diabetes as outcome. It was observed that bacterial pneumonia increases the incidence of GDM (OR = 1.150 (1.027-1.274, P = 0.011) and T1DM (OR = 1.277 (1.024-1.531), P = 0.016). In the reverse MR analysis, it was observed that GDM (OR = 1.112 (1.023-1.201, P = 0.009) is associated with an elevated risk of bacterial pneumonia. However, no significant association was observed bacterial pneumonia with T1DM and other types of diabetes (P > 0.05). CONCLUSION: This study utilizing MR methodology yields robust evidence supporting a bidirectional causal association between bacterial pneumonia and GDM. Furthermore, our findings suggest a plausible causal link between bacterial pneumonia and T1DM.

Clinical characteristics and risk factors associated with secondary bacterial pneumonia among COVID-19 patients in ICU.

INTRODUCTION: COVID-19 and secondary infections developing during COVID-19 follow-up are one of the most important causes of morbidity and mortality in intensive care units (ICU). In this study, we aimed to determine the frequency, microbiology, risk factors, and outcomes of secondary bacterial pneumonia in hospitalized patients due to COVID-19. METHODOLOGY: We studied all patients with bacterial pneumonia developed in patients with severe COVID-19 infection in the COVID-19 intensive care unit in a single-center hospital between March 16, 2020 and June 17, 2020. Patients hospitalized and followed up in the ICU for respiratory failure were examined in terms of secondary infection affecting morbidity and mortality. RESULTS: Ninety-six (20%) of 471 patients had secondary bacterial pneumonia, respectively; of the leading pathogens were Acinetobacter baumannii (44.8%) and Klebsiella pneumoniae (39.6%), followed by Pseudomonas aeruginosa (4.2%), Escherichia coli (3.1%), methicillin-resistant Staphylococcus aureus (MRSA) (3.1%), Streptococcus pneumoniae (3.1%), and Methicillin-susceptible Staphylococcus aureus (MSSA) (1%). The mortality rate among infected (75% / 47.5%) was significantly higher than in uninfected patients. Associated with the development of secondary bacterial pneumonia in COVID-19 patients; corticosteroid therapy [odds ratio (OR) 6250, 95% confidence interval (CI) 1.383-28.571, p = 0.017), corticosteroid dose (OR 8.862 CI 2.299-70.258, p= 0.006), duration of mechanical ventilation (OR 1.199 CI) 1.088-1.322, p< 0.001). CONCLUSIONS: Secondary bacterial pneumonia was found to be associated with the severity and survival of the disease in patients admitted to ICU due to COVID-19. Duration of mechanical ventilation and use of corticosteroids and high-dose corticosteroids are risk factors for secondary bacterial pneumonia.

External validation of a multivariable prediction model for identification of pneumonia and other serious bacterial infections in febrile immunocompromised children.

OBJECTIVE: To externally validate and update the Feverkids tool clinical prediction model for differentiating bacterial pneumonia and other serious bacterial infections (SBIs) from non-SBI causes of fever in immunocompromised children. DESIGN: International, multicentre, prospective observational study embedded in PErsonalised Risk assessment in Febrile illness to Optimise Real-life Management across the European Union (PERFORM). SETTING: Fifteen teaching hospitals in nine European countries. PARTICIPANTS: Febrile immunocompromised children aged 0-18 years. METHODS: The Feverkids clinical prediction model predicted the probability of bacterial pneumonia, other SBI or no SBI. Model discrimination, calibration and diagnostic performance at different risk thresholds were assessed. The model was then re-fitted and updated. RESULTS: Of 558 episodes, 21 had bacterial pneumonia, 104 other SBI and 433 no SBI. Discrimination was 0.83 (95% CI 0.71 to 0.90) for bacterial pneumonia, with moderate calibration and 0.67 (0.61 to 0.72) for other SBIs, with poor calibration. After model re-fitting, discrimination improved to 0.88 (0.79 to 0.96) and 0.71 (0.65 to 0.76) and calibration improved. Predicted risk <1% ruled out bacterial pneumonia with sensitivity 0.95 (0.86 to 1.00) and negative likelihood ratio (LR) 0.09 (0.00 to 0.32). Predicted risk >10% ruled in bacterial pneumonia with specificity 0.91 (0.88 to 0.94) and positive LR 6.51 (3.71 to 10.3). Predicted risk <10% ruled out other SBIs with sensitivity 0.92 (0.87 to 0.97) and negative LR 0.32 (0.13 to 0.57). Predicted risk >30% ruled in other SBIs with specificity 0.89 (0.86 to 0.92) and positive LR 2.86 (1.91 to 4.25). CONCLUSION: Discrimination and calibration were good for bacterial pneumonia but poorer for other SBIs. The rule-out thresholds have the potential to reduce unnecessary investigations and antibiotics in this high-risk group.

Case Report: Vagal Nerve Neuritis Associated with Pulmonary Melioidosis Provides Potential Insights into the Pathophysiology of Neuromelioidosis.

Encephalomyelitis is the most frequent manifestation of neuromelioidosis in Australia. It is hypothesized that Burkholderia pseudomallei causes encephalomyelitis after entering the brain directly, if complicating a scalp infection, or after traveling to the brain within peripheral or cranial nerves. A 76-year-old man presented with fever, dysphonia, and hiccups. Chest imaging demonstrated extensive bilateral pneumonia with mediastinal lymphadenopathy, blood cultures isolated B. pseudomallei, and nasendoscopy confirmed a left vocal cord palsy. Magnetic resonance imaging identified no intracranial abnormality but demonstrated an enlarged, enhancing left vagus nerve, consistent with neuritis. We hypothesize that B. pseudomallei invaded the vagus nerve in the thorax, was traveling proximally-involving the left recurrent laryngeal nerve and causing the left vocal cord palsy, but had not yet reached the brainstem. Given the frequency of pneumonia in cases of melioidosis, the vagus nerve may represent an alternative, and indeed common, route for B. pseudomallei to enter the brainstem in cases of melioidosis-related encephalomyelitis.

Identification of priority pathogens for aetiological diagnosis in adults with community-acquired pneumonia in China: a multicentre prospective study.

BACKGROUND: Community-acquired pneumonia (CAP) is a major public health challenge worldwide. However, the aetiological and disease severity-related pathogens associated with CAP in adults in China are not well established based on the detection of both viral and bacterial agents. METHODS: A multicentre, prospective study was conducted involving 10 hospitals located in nine geographical regions in China from 2014 to 2019. Sputum or bronchoalveolar lavage fluid (BALF) samples were collected from each recruited CAP patient. Multiplex real-time PCR and bacteria culture methods were used to detect respiratory pathogens. The association between detected pathogens and CAP severity was evaluated. RESULTS: Among the 3,403 recruited eligible patients, 462 (13.58%) had severe CAP, and the in-hospital mortality rate was 1.94% (66/3,403). At least one pathogen was detected in 2,054 (60.36%) patients, with two or more pathogens were co-detected in 725 patients. The ten major pathogens detected were Mycoplasma pneumoniae (11.05%), Haemophilus influenzae (10.67%), Klebsiella pneumoniae (10.43%), influenza A virus (9.49%), human rhinovirus (9.02%), Streptococcus pneumoniae (7.43%), Staphylococcus aureus (4.50%), adenovirus (2.94%), respiratory syncytial viruses (2.35%), and Legionella pneumophila (1.03%), which accounted for 76.06-92.52% of all positive detection results across sampling sites. Klebsiella pneumoniae (p < 0.001) and influenza viruses (p = 0.005) were more frequently detected in older patients, whereas Mycoplasma pneumoniae was more frequently detected in younger patients (p < 0.001). Infections with Klebsiella pneumoniae, Staphylococcus aureus, influenza viruses and respiratory syncytial viruses were risk factors for severe CAP. CONCLUSIONS: The major respiratory pathogens causing CAP in adults in China were different from those in USA and European countries, which were consistent across different geographical regions over study years. Given the detection rate of pathogens and their association with severe CAP, we propose to include the ten major pathogens as priorities for clinical pathogen screening in China.

Risk factors for in-hospital mortality and secondary bacterial pneumonia among hospitalized adult patients with community-acquired influenza: a large retrospective cohort study.

BACKGROUND: Secondary bacterial pneumonia is an important complication of seasonal influenza, but little data is available about impact on death and risk factors. This study identified risk factors for all-cause in-hospital mortality and secondary bacterial pneumonia among hospitalized adult patients with community-acquired influenza. METHODS: A retrospective cohort study was performed at a tertiary teaching hospital in southwest China. The study cohort included all adult hospitalized patients with a laboratory-confirmed, community-acquired influenza virus infection during three consecutive influenza seasons from 2017 to 2020. Cause-specific Cox regression was used to analyze risk factors for mortality and secondary bacterial pneumonia, respectively, accounting for competing events (discharge alive and discharge alive or death without secondary bacterial pneumonia, respectively). RESULTS: Among 174 patients enrolled in this study, 14.4% developed secondary bacterial pneumonia and 11.5% died during hospitalization. For all-cause in-hospital mortality, time-varying secondary bacterial pneumonia was a direct risk factor of death (cause-specific hazard ratio [csHR] 3.38, 95% confidence interval [CI] 1.25-9.17); underlying disease indirectly increased death risk through decreasing the hazard of being discharged alive (csHR 0.55, 95% CI 0.39-0.77). For secondary bacterial pneumonia, the final model only confirmed direct risk factors: age ≥ 65 years (csHR 2.90, 95% CI 1.27-6.62), male gender (csHR 3.78, 95% CI 1.12-12.84) and mechanical ventilation on admission (csHR 2.96, 95% CI 1.32-6.64). CONCLUSIONS: Secondary bacterial pneumonia was a major risk factor for in-hospital mortality among adult hospitalized patients with community-acquired influenza. Prevention strategies for secondary bacterial pneumonia should target elderly male patients and critically ill patients under mechanical ventilation.

OBESE MICE WITH PNEUMONIA HAVE HYPERLEPTINEMIA AND INCREASED PULMONARY SIGNAL TRANSDUCER AND ACTIVATOR OF TRANSCRIPTION 3 ACTIVATION.

ABSTRACT: Obesity is an ongoing epidemic that influences pathobiology in numerous disease states. Obesity is associated with increased plasma leptin levels, a hormone that activates the signal transducer and activator of transcription 3 (STAT3) pathway. Pneumonia is a significant cause of morbidity and mortality. During pneumonia, inflammatory pathways including STAT3 are activated. Outcomes in obese patients with pneumonia are mixed, with some studies showing obesity increases harm and others showing benefit. It is unclear whether obesity alters STAT3 activation during bacterial pneumonia and how this might impact outcomes from pneumonia. We used a murine model of obesity and pneumonia challenge with Pseudomonas aeruginosa in obese and nonobese mice to investigate the effect of obesity on STAT3 activation. We found obese mice with bacterial pneumonia had increased mortality compared with nonobese mice. Inflammatory markers, IL-6 and TNF-α, and lung neutrophil infiltration were elevated at 6 h after pneumonia in both nonobese and obese mice. Obese mice had greater lung injury compared with nonobese mice at 6 h after pneumonia. Leptin and insulin levels were higher in obese mice compared with nonobese mice, and obese mice with pneumonia had higher pulmonary STAT3 activation compared with nonobese mice.

The utility of procalcitonin for diagnosing bacteremia and bacterial pneumonia in hospitalized oncology patients.

PURPOSE: Procalcitonin (PCT) is an inflammatory marker elevated in bacteremia and bacterial pneumonia. We aimed to assess the real-world diagnostic accuracy of PCT in hospitalized patients with malignancy. METHODS: A retrospective cohort of 715 patients with cancer who had PCT measured during 750 admissions was analyzed. Diagnosis of bacteremia was determined using blood culture data. Diagnosis of bacterial pneumonia was based on radiographic infiltrate and/or sputum culture. PCT's performance was assessed using receiver operating characteristic (ROC) curves, sensitivity, and specificity. RESULTS: Patients had bacteremia, bacterial pneumonia, or both during 210 admissions (28%). PCT elevation above 0.5 ng/mL was significantly associated with diagnosed infection in the overall population (p < 0.0001) and in subgroups with solid tumor malignancies (p < 0.0001) and hematologic malignancies (p = 0.008). PCT was associated with infectious status in patients with any metastases, but not those with primary lung cancer, lung metastases, neuroendocrine tumors, febrile neutropenia, or history of bone marrow transplant (BMT). The area under the ROC curve for PCT in the overall population was 0.655. An ideal cutoff of 0.21 ng/mL led to a sensitivity of 60% and specificity of 59%. At cutoffs of 0.5 ng/mL and 0.05 ng/mL, PCT's sensitivity was 39% and 94%, while specificity was 79% and 17%, respectively. CONCLUSION: In this large cohort of hospitalized oncology patients, PCT elevation was associated with diagnosed bacteremia and/or bacterial pneumonia. However, specificity was limited, and PCT elevation was not associated with diagnosed infection in some subpopulations. While PCT may have some diagnostic utility for hospitalized oncology patients, values must be interpreted cautiously and considering clinical context.

The application of cluster nursing to prevent bacterial pneumonia in stroke patients in neurology department.

The research aims to explore the intervention effect of cluster nursing methods on bacterial pneumonia in stroke patients in neurology. A retrospective analysis is conducted on 120 patients diagnosed with stroke in the hospital from 2020 to 2022, who are diagnosed as stroke patients in the neurology department by doctors. 120 patients are randomly separated into a control group (CG) and a research group (RG) for the experiment, with 60 people in each group. The CG receive normal nursing; The RG adopt cluster nursing methods. Comparison have done in the general information, nursing satisfaction, physical improvement after intervention, and oral hygiene indicators of the 2 groups of patients, and the intervention effect of the 2 nursing methods on patients suffering from bacterial pneumonia is evaluated. When the time reached the 7th day, the nutritional risk screening scores of both groups were (9.53 ± 2.29) and (8.10 ± 2.12), respectively. The serum albumin levels were (36.46 ± 4.80) g/L and (34.16 ± 3.69) g/L, respectively. After simultaneous nursing intervention, there were P < .005 in respiratory rates in the 2nd and 4th months of intervention, as well as after the completion of nursing intervention. The respiratory rates of the RG patients improved toward a larger range of normal respiratory rates, with significant statistical significance (P < .005). As time passed, the number of people with shortness of breath in the CG increased sharply to 46, while those in the RG was only 27, indicating P < .05 between the 2 groups. At the beginning of the 3rd month, the satisfaction rates of the RG and the CG were (92.33 ± 1.17)% and (78.18 ± 1.07)%, respectively, and there was P < .0.05 between the 2 groups of data. The cluster nursing strategy has a significant relieving effect on bacterial pneumonia in stroke patients in the neurology department, which can effectively reduce the probability of pneumonia, improve their physical condition, and enhance their quality of life. It has certain clinical application value.

Impact of body mass index on in-hospital mortality in older patients hospitalized for bacterial pneumonia with non-dialysis-dependent chronic kidney disease.

BACKGROUND: Low body mass index (BMI) in older individuals with decreased kidney function is important because of its association with poor prognosis and frailty. Herein, we aimed to clarify the association between BMI and in-hospital mortality among older patients with non-dialysis-dependent chronic kidney disease (CKD) stratified by kidney function. METHODS: Using data from the Medical Vision Database, this multicentre cohort study included people aged ≥ 60 years with an estimated glomerular filtration rate of < 60 ml/min/1.73 m2 but without dialysis dependency, hospitalised for bacterial pneumonia during 2014-2019. We compared the risk of in-hospital death between patients with BMI categories based on the quartiles (low, medium-low, medium-high, and high) setting medium-high BMI as a reference. We further assessed the association with BMI using a cubic spline, setting BMI as a nonlinear continuous variable and a BMI of 22 kg/m2 as a reference. We also evaluated the association between BMI and kidney function using a generalised additive model adjusted for interaction terms between nonlinear continuous BMI and kidney function. RESULTS: We obtained data for 3,952 patients, with 350 (8.9%) in-hospital deaths. When compared with medium-high BMI, low BMI was associated with an increased risk of death and longer hospital stay, whereas the other two categories were comparable. Models using a cubic spline showing an association between BMI and in-hospital death showed an L-shaped curve; BMI < 22.0 kg/m2 was associated with an increased risk for mortality, and at a BMI of 18.5 kg/m2, the odds ratio was 1.43 with a 95% confidence interval of 1.26-1.61 when compared with a BMI of 22.0 kg/m2. Analysis of the interactive effects of kidney function using the generalised additive model showed that a protective association of high BMI tapered along with decreased kidney function. CONCLUSIONS: This cohort study suggests not only that lower BMI and low kidney function are associated with in-hospital mortality independently but also that the protective effects of high BMI weaken as kidney function decreases via the analysis of the interaction terms. This study highlights the necessity for the prevention of underweight and demonstrates the interaction between BMI and kidney function in older patients with non-dialysis-dependent CKD.

The influenza-injured lung microenvironment promotes MRSA virulence, contributing to severe secondary bacterial pneumonia.

Influenza infection is substantially worsened by the onset of secondary pneumonia caused by bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA). The bidirectional interaction between the influenza-injured lung microenvironment and MRSA is poorly understood. By conditioning MRSA ex vivo in bronchoalveolar lavage fluid collected from mice at various time points of influenza infection, we found that the influenza-injured lung microenvironment dynamically induces MRSA to increase cytotoxin expression while decreasing metabolic pathways. LukAB, a SaeRS two-component system-dependent cytotoxin, is particularly important to the severity of post-influenza MRSA pneumonia. LukAB's activity is likely shaped by the post-influenza lung microenvironment, as LukAB binds to (and is activated by) heparan sulfate (HS) oligosaccharide sequences shed from the epithelial glycocalyx after influenza. Our findings indicate that post-influenza MRSA pneumonia is shaped by bidirectional host-pathogen interactions: host injury triggers changes in bacterial expression of toxins, the activity of which may be shaped by host-derived HS fragments.

[Etiology of bacterial pneumonias in patients with COVID-19]. / Etiología de neumonías bacterianas en pacientes con COVID-19.

Background: Aggregate bacterial pneumonia plays a fundamental role in mortality of patients hospitalized with COVID-19. Objective: To estimate the association of aggregated bacterial pneumonia with mortality in patients at Hospital Especialidades "La Raza". Material and methods: Analytical cross-sectional study, 252 COVID-19 patients, chest x-ray and culture of bronchial secretion or expectoration. Data taken from the SIOC electronic file and the IZASAlab platform. Results: 252 participants, positive culture, 89 patients, 35.3%, isolation of K. pneumoniae (22.5%), A. baumannii (20.2%), P. aeruginosa (13.5%) and S. aureus (11.2%), antimicrobial resistance 37.1%. 43.7% died, lung damage greater than 50% RMa 2.25 (95% CI 1.01-5.11) p=0.04 against minor lung damage; microorganism in culture RMa 9.04 (95% CI 3.06-26.74) p=0.000; antimicrobial resistance RMa 7.57 (95% CI 1.34-42.79) p=0.02; S. aureus RMa 1.24 (95% CI 0.36-4.23) p=0.73; A. baumannii RMa 3.74 (95% CI 1.41-9.91) p=0.008; K. pneumoniae RMa 4.12 (95% CI 1.55-10.97) p=0.005; and P. aeruginosa RMa 6.89 (95% CI 1.62-17.61) p=0.01. Uncontrolled Diabetes RMa 1.61 (IC95% 1.1-2.9) p=0.018. Conclusions: The development of added bacterial pneumonia increases the probability of death 2 times more, it amounts to 6 times more if there is antimicrobial resistance, it is observed to a greater extent for A. baumannii, K. pneumoniae and P. aeruginosa.

Introducción: la neumonía bacteriana agregada en pacientes COVID-19 tiene un papel determinante en la mortalidad hospitalaria. Objetivo: estimar la asociación de neumonía bacteriana agregada con la mortalidad de pacientes COVID-19 en el Hospital Especialidades de "La Raza". Material y métodos: estudio transversal analítico con 252 pacientes con COVID-19; se obtuvieron los datos del expediente electrónico y plataforma IZASAlab, se tomó Rx de tórax y cultivo de secreción bronquial o expectoración. Resultados: de 252 participantes resultó cultivo positivo en 89 pacientes (35.3%), aislamiento de K. pneumoniae (22.5%), A. baumannii (20.2%), P. aeruginosa (13.5%) y S. aureus (11.2%); hubo resistencia antimicrobiana en 37.1% y fallecieron 43.7%. El daño pulmonar mayor al 50% en la Rx de tórax tuvo RMa 2.25 (IC95%: 1.01-5.11) p = 0.04 para mortalidad; cultivo positivo RMa 9.04 (IC95%: 3.06-26.74) p = 0.000; resistencia antimicrobiana RMa 7.57 (IC95%: 1.34-42.79) p = 0.02; S. aureus RMa 1.24 (IC95%: 0.36-4.23) p = 0.73; A. baumannii RMa 3.74 (IC95%: 1.41-9.91) p = 0.008; K. pneumoniae RMa 4.12 (IC95%: 1.55-10.97) p = 0.005, y P. aeruginosa RMa 6.89 (IC95%: 1.62-17.61) p = 0.01. Diabetes Mellitus descontrolada RMa 1.61 (IC95%: 1.1-2.9) p = 0.018. Conclusiones: el desarrollo neumonía bacteriana agregada en pacientes COVID-19 incrementa dos veces más la probabilidad de muerte y seis veces más si existe resistencia antimicrobiana de A. baumannii, K. pneumoniae o P. aeruginosa.

Penicillin Allergy Label Is Associated With Worse Clinical Outcomes in Bacterial Pneumonia.

BACKGROUND: Penicillins (PCNs) are a first-line treatment option for bacterial pneumonia. PCN allergy label can delay antimicrobial treatment and result in the use of alternative antibiotic regimens risking an inadequate response to treatment and potentially increased adverse drug reactions. OBJECTIVE: To investigate the impact of PCN allergy label on clinical outcomes of bacterial pneumonia. METHODS: This retrospective cohort study used TriNetX, a web-based tool for population cohort research, to identify adult patients with and without PCN allergy label diagnosed with bacterial pneumonia. Cohorts were matched for baseline demographics and chronic medical conditions. The 30-day risks of hospitalization, acute respiratory failure, intubation, need for intensive level of care, and mortality were compared. Antibiotics used and their possible adverse reactions were explored. RESULTS: After matching, there were 68,748 patients in each cohort. Patients with bacterial pneumonia with PCN allergy label had higher risks of hospitalization (risk ratio [RR], 1.23; 95% confidence interval [CI], 1.22-1.24), acute respiratory failure (RR, 1.14; 95% CI, 1.12-1.15), intubation (RR, 1.18; 95% CI, 1.13-1.22), intensive level of care (RR, 1.11; 95% CI, 1.08-1.14), and mortality (RR, 1.08; 95% CI, 1.04-1.13) compared with patients without PCN allergy label. Patients with PCN allergy label had decreased use of PCNs and cephalosporins and increased utilization of other antibiotic classes compared with patients without PCN allergy label. PCN allergy label was also associated with increased risk of adverse drug reactions. CONCLUSION: PCN allergy label is associated with worse clinical outcomes in bacterial pneumonia, and risk mitigation strategies should be considered.