Pseudomonas fluorescens pneumonia.

Pseudomonas fluorescens (P. fluorescens) is not generally considered a bacterial pathogen in humans; however, multiple culture-based and culture-independent studies have identified it in the indigenous microbiota of multiple body sites. We herein report a rare case of pneumonia caused by P. fluorescens. A man in his 80 s with chronic obstructive pulmonary disease and diabetes mellitus was diagnosed with stage II rectal cancer. He underwent laparoscopic surgery, and on the 6th postoperative day, he developed a high fever. Chest computed tomography revealed infiltration in the left lower lung. Gram staining of the sputum showed Gram-negative rods phagocytosed by neutrophils, suggesting postoperative nosocomial pneumonia. The patient was started on tazobactam/piperacillin, and his pneumonia quickly improved. Later, only P. fluorescens was detected in a sputum culture. It was susceptible to common antipseudomonal agents. Gram staining of P. fluorescens appears to show a slightly thicker and larger morphology in comparison to Pseudomonas aeruginosa. Although there have been reports of opportunistic infections caused by P. fluorescens in immunosuppressed patients, including those with advanced cancer, most have been bloodstream infections, with very few reports of pneumonia alone. Clinicians should be aware that patients, who are not necessarily immunosuppressed, may develop pneumonia caused by P. fluorescens.

Evaluation of the BioFire® FilmArray® Pneumonia plus Panel for Detecting Bacterial Etiological Agents of Lower Respiratory Tract Infections in an Oncologic Hospital. Comparison with Conventional Culture Method.

Conventional methods used to determine pneumonia pathogens are characterized by low sensitivity and long turnaround times. Introducing new tests with better parameters in patients at higher risk of infections is highly anticipated. The results of the conventional quantitative culture method (CM) in determining the bacterial etiology of pneumonia were compared with the results of the Pneumonia plus Panel test (PNP; BioFire® Diagnostics, USA) in 79 samples of bronchoalveolar lavage (BAL). Materials were collected from 79 patients with suspected pneumonia treated in an oncologic hospital due to solid tumors. Only 16/79 BAL samples (20.3%) were true positive (TP) for bacterial etiology in CM vs. 27/79 samples (34.2%) true positive in the PNP test. The total agreement between methods of interpreting the result (positive or negative) was 84.8%. The most prevalent pathogens in both methods were Staphylococcus aureus, followed by Escherichia coli, Pseudomonas aeruginosa, and Haemophilus influenzae. The PNP test identified several respiratory pathogens that were not grown in culture. The semiquantitative value reported by the PNP test was higher than that reported by culture. The PNP test vs. combined test (PNP test and CM methods) demonstrated positive predictive value (PPV) and negative predictive value (NPV) values of 100.0% and 98.1%, and the sensitivity and specificity were 96.4% and 100.0%. The PNP test is a good tool for determining the etiology of bacterial pneumonia and may support the care of an oncologic patient. However, further large-sample studies are needed to research in strictly defined groups of oncologic patients.

Childhood Pneumonia: What's Unchanged, and What's New?

Childhood pneumonia is still a significant clinical and public health problem. India contributes the highest number of deaths due to pneumonia, accounts for about 20% of global mortality among under five children. Various etiologic agents including bacteria, viruses and atypical organism are responsible for childhood pneumonia. Recent studies suggest that viruses are one of the major causes of childhood pneumonia. Among viruses, respiratory syncytial virus has got great attention and several recent studies are reporting it as an important organism for pneumonia. Lack of exclusive breast feeding during first six months, improper timing of start and content of complimentary feeding, anemia, undernutrition, indoor pollution due to tobacco smoking and use of coal and wood for cooking food and lack of vaccinations are important risk factors. X-ray chest is not routinely performed to diagnose pneumonia while use of lung ultrasound is increasing to detect consolidation, pleural effusion, pneumothorax and pulmonary edema (interstitial syndrome). Role of C-reactive protein (CRP) and procalcitonin is similar, to differentiate between viral and bacterial pneumonia, however duration of antibiotics is better guided by procalcitonin. Newer biomarkers like IL-6, presepsin and triggering receptor expressed on myeloid cells 1 are needed to be evaluated for their use in children. Hypoxia is significantly associated with childhood pneumonia. Therefore, use of pulse oximetry should be encouraged for early detection and prompt treatment of hypoxia to prevent adverse outcomes. Among the available tools for risk of mortality assessment in children due to pneumonia, PREPARE score is the best but external validation will be needed.

Placental mesenchymal stem cells boost M2 alveolar over M1 bone marrow macrophages via IL-1ß in Klebsiella-mediated acute respiratory distress syndrome.

RATIONALE: Acute respiratory distress syndrome (ARDS) is a lethal complication of severe bacterial pneumonia due to the inability to dampen overexuberant immune responses without compromising pathogen clearance. Both of these processes involve tissue-resident and bone marrow (BM)-recruited macrophage (MΦ) populations which can be polarised to have divergent functions. Surprisingly, despite the known immunomodulatory properties of mesenchymal stem cells (MSCs), simultaneous interactions with tissue-resident and recruited BMMΦ populations are largely unexplored. OBJECTIVES: We assessed the therapeutic use of human placental MSCs (PMSCs) in severe bacterial pneumonia with elucidation of the roles of resident alveolar MΦs (AMΦs) and BMMΦs. METHODS: We developed a lethal, murine pneumonia model using intratracheal infection of a clinically relevant Klebsiella pneumoniae (KP) strain with subsequent intravenous human PMSC treatment. Pulmonary AMΦ and recruited BMMΦ analyses, histological evaluation, bacterial clearance and mice survival were assessed. To elucidate the role of resident AMΦs in improving outcome, we performed AMΦ depletion in the KP-pneumonia model with intratracheal clodronate pretreatment. MEASUREMENTS AND MAIN RESULTS: Human PMSC treatment decreased tissue injury and improved survival of severe KP-pneumonia mice by decreasing the presence and function of recruited M1 BMMΦ while preserving M2 AMΦs and enhancing their antibacterial functions. Interestingly, PMSC therapy failed to rescue AMΦ-depleted mice with KP pneumonia, and PMSC-secreted IL-1ß was identified as critical in increasing AMΦ antibacterial activities to significantly improve pathogen clearance-especially bacteraemia-and survival. CONCLUSIONS: Human PMSC treatment preferentially rescued resident M2 AMΦs over recruited M1 BMMΦs with overall M2 polarisation to improve KP-related ARDS survival.

Seroprevalence of community-acquired atypical bacterial pneumonia among adult COVID-19 patients from a single center in Al Madinah Al Munawarah, Saudi Arabia: A retrospective cohort study.

OBJECTIVES: To investigate the seroprevalence of the community-acquired bacterial that causes atypical pneumonia among confirmed severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) patients. METHODS: In this cohort study, we retrospectively investigated the seroprevalence of Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila among randomly selected 189 confirmed COVID-19 patients at their time of hospital presentation via commercial immunoglobulin M (IgM) antibodies against these bacteria. We also carried out quantitative measurements of procalcitonin in patients' serum. RESULTS: The seropositivity for L. pneumophila was 12.6%, with significant distribution among patientsolder than 50 years (χ2 test, p=0.009), while those of M. pneumoniae was 6.3% and C. pneumoniae was 2.1%, indicating an overall co-infection rate of 21% among COVID-19 patients. No significant difference (χ2 test, p=0.628) in the distribution of bacterial co-infections existed between male and female patients. Procalcitonin positivity was confirmed amongst 5% of co-infected patients. CONCLUSION: Our study documented the seroprevalence of community-acquired bacteria co-infection among COVID-19 patients. In this study, procalcitonin was an inconclusive biomarker for non-severe bacterial co-infections among COVID-19 patients. Consideration and proper detection of community-acquired bacterial co-infection may minimize misdiagnosis during the current pandemic and positively reflect disease management and prognosis.

Clinical profile and microbiological aetiology diagnosis in adult patients hospitalized with community-acquired pneumonia.

Early introduction of appropriate antibiotherapy is one of the major prognostic-modifying factors in community acquired pneumonia (CAP). Despite established guidelines for empirical therapy, several factors may influence etiology and, consequently, antibiotic choices. The aims of this study were to analyze the etiology of CAP in adults admitted to a northern Portugal University Hospital and evaluate the yield of the different methods used to reach an etiological diagnosis, as well as analyze of the impact of patient demographic and clinical features on CAP etiology. We retrospectively analyzed 1901 cases of CAP with hospitalization. The diagnostic performance increased significantly when blood and sputum cultures were combined with urinary antigen tests. The most frequent etiological agent was Streptococcus pneumoniae (45.7%), except in August, when it was overtaken by gram-negative bacilli (GNB) and Legionella pneumophila infections. Viral infections were almost exclusive to winter and spring. A negative microbiological result was associated with increasing age, non-smoking and lack of both blood/sputum cultures. Younger age was a predictor for S. pneumoniae, Influenza and L. pneumophila infections. Active smoking without any previously known respiratory disease was a risk factor for legionellosis. COPD was associated with Haemophilus influenzae cases, while dementia was typical in GNB and S. aureus patients. Diabetes mellitus (DM) and heart disease were negative predictors of S. pneumoniae and H. influenzae, respectively. P. aeruginosa was an independent risk factor for mortality (OR 13.02, 95% CI 2.94-57.7). This study highlights the importance of a comprehensive microbiological diagnostic workup and provides clues to predicting the most probable CAP causative agents, based on a patient's clinical profile. These may be taken into account when establishing first line antibiotherapy.

Severe Pneumonia Caused by Methicillin-Resistant Staphylococcus pseudintermedius in an Oncology Patient: Case Report and Literature Review.

Staphylococcus pseudintermedius is usually a commensal bacterium of microbiota of dogs and cats that can become pathogenic in these animals. In the past two decades, an increasing number of human infections caused by this pathogen was reported; only two pediatric cases were due to methicillin-susceptible isolates. We describe the first case of methicillin-resistant S. pseudintermedius diagnosed in a 12-year-old immunocompromised girl with refractory anaplastic ependymoma, presented with life-threatening pneumonia and bacteremia. The girl had close contact with her two pet dogs. This case emphasizes that immunocompromised children should be advised on proper handling of household pets to minimize the risk of infection, which could be life threatening.

Aspectos epidemiológicos, clínicos y microbiológicos en pacientes menores de 5 años con neumonía bacteriana / Epidemiological, clinical and microbiologic aspects in patients under 5 years with bacterial pneumonia

Introducción: Las infecciones respiratorias agudas abarcan entre 20 y 40 % del total de todas las hospitalizaciones y 20 - 34 % de las muertes en menores de 5 años de edad, fundamentalmente a expensas de neumonía. Objetivo: Describir aspectos epidemiológicos, clínicos y microbiológicos en pacientes menores de 5 años con neumonía bacteriana. Métodos: Se realizó un estudio descriptivo y transversal de 39 pacientes con neumonía y aislamientos bacterianos en hemocultivos, líquido pleural y/o exudados nasofaringeos, ingresados en el Hospital Infantil Docente Sur Antonio María Béguez Cesar de Santiago de Cuba, desde enero de 2018 hasta diciembre de 2019. Se analizaron variables de interés, tales como edad, sexo, factores de riesgo, sintomatología y cultivos microbiológicos. Se utilizaron la frecuencia absoluta y el porcentaje como medidas de resumen. Resultados: Prevalecieron los pacientes entre 1 - 4 años de edad, el sexo femenino y los hemocultivos con estafilococos coagulasa negativo, así como neumococos, estos últimos también aislados en exudados nasofaríngeos. Los factores de riesgo más frecuentes fueron infección respiratoria aguda previa, uso anticipado de antibióticos, asistencia a círculo infantil, supresión precoz de lactancia materna, fiebre, tos, tiraje y alteraciones del murmullo vesicular. Predominaron la insuficiencia respiratoria aguda y el derrame pleural como complicaciones. Se notificó más gravedad en los lactantes y ocurrieron 2 decesos, para una letalidad de 1,47 %. Conclusiones: La conjunción de factores de riesgo detectados, la baja positividad de los cultivos, la identificación de bacterias prevalentes en hemocultivos y el descenso de la letalidad resultaron de interés en el estudio.

Introduction: Acute respiratory infections take in between 20 and 40 % of all the hospitalizations and 20 - 34% of deaths in children under 5 years, fundamentally at the expense of pneumonia. Objective: To describe epidemiologic, clinical and microbiologic aspects in patients under 5 years with bacterial pneumonia. Methods: A descriptive and cross-sectional study of 39 patients with pneumonia and bacterial isolations in hemocultures, pleural fluid and/or nasopharyngeal swabs was carried out. They were admitted to Antonio María Béguez Cesar Southern Teaching Children Hospital in Santiago de Cuba, from January, 2018 to December, 2019. Variables of interest were analyzed, such as age, sex, risk factors, symptomatology and microbiologic cultures. The absolute frequency and the percentage as summary measures were used. Results: There was a prevalence of patients among 1 - 4 years, female sex and the hemocultures with negative coagulase staphylococcu, as well as pneumococus, these last ones also isolated in nasopharingeal swabs. The most frequent risk factors were previous acute respiratory infection, premature use of antibiotics, attendance to day care center, early suppression of breastfeeding, fever, cough, tirage and changes of the vesicular breath sound. The acute respiratory failure and pleural effusion as complications prevailed. More seriousness was notified in infants and there were 2 deaths, for a letality of 1.47 %. Conclusions: The combination of detected risk factors, low positivity of the cultures, identification of bacterias prevalents in hemocultures and the decrease of letality was of interest in the study.

Evaluation of 16S rRNA methyltransferase gene in aminoglycosides resistant isolates of cancer patients.

Aminoglycosides are used in empiric treatment of critically ill patients. Efficacy of aminoglycoside has been reduced due to dissemination of resistance. The aim of this study was to evaluate aminoglycoside resistance in cancer patients with pneumoniae. A total of 150 Bronchoalveolar lavage and Bronchial washing samples were collected from cancer patients. The samples were identified with standard microbiological procedures. Phenotypic susceptibility pattern of the isolates was determined against various groups of antibiotics such as Penicillins, Cephalosporins, Carbapenems, Monobactams, Aminoglycosides, Tetracyclins, Glycopeptides and Sulphonamides. The isolates with phenotypic resistant to aminoglycosides were further evaluated for the presence of armA gene. The strains of E. coli (12.5%), S. aureus (15.6%), Streptococcus (15.6%), Pseudomonas (18.7%) and K. pneumoniae (37.5%) were isolated. The phenotypic resistance profile showed highest resistance against aminoglycosides (Tobramycin, 53.1% Gentamicin and 50% Amikacin) followed by cephalosporins and sulfonamides group. The armA gene was detected in aminoglycoside resistant isolates. The overall genotypic resistance was evaluated as 21.8%. The armA gene was found in K.pneumoniae 23.5%, Pseudomonas 11.8% (4/24) and E. coli 5.9%. High level resistance to aminoglycosides raises therapeutic concern to health care professionals. These findings highlight the importance of effective monitoring and surveillance to the use of broad-spectrum antibiotics.

Vaccination induces rapid protection against bacterial pneumonia via training alveolar macrophage in mice.

Vaccination strategies for rapid protection against multidrug-resistant bacterial infection are very important, especially for hospitalized patients who have high risk of exposure to these bacteria. However, few such vaccination strategies exist due to a shortage of knowledge supporting their rapid effect. Here, we demonstrated that a single intranasal immunization of inactivated whole cell of Acinetobacter baumannii elicits rapid protection against broad A. baumannii-infected pneumonia via training of innate immune response in Rag1-/- mice. Immunization-trained alveolar macrophages (AMs) showed enhanced TNF-α production upon restimulation. Adoptive transfer of immunization-trained AMs into naive mice mediated rapid protection against infection. Elevated TLR4 expression on vaccination-trained AMs contributed to rapid protection. Moreover, immunization-induced rapid protection was also seen in Pseudomonas aeruginosa and Klebsiella pneumoniae pneumonia models, but not in Staphylococcus aureus and Streptococcus pneumoniae model. Our data reveal that a single intranasal immunization induces rapid and efficient protection against certain Gram-negative bacterial pneumonia via training AMs response, which highlights the importance and the possibility of harnessing trained immunity of AMs to design rapid-effecting vaccine.

Contribution of dipeptidyl peptidase 4 to non-typeable Haemophilus influenzae-induced lung inflammation in COPD.

Dipeptidyl peptidase 4 (DPP4) expression is increased in the lungs of chronic obstructive pulmonary disease (COPD). DPP4 is known to be associated with inflammation in various organs, including LPS-induced acute lung inflammation. Since non-typeable Haemophilus influenzae (NTHi) causes acute exacerbations in COPD patients, we examined the contribution of DPP4 in NTHi-induced lung inflammation in COPD. Pulmonary macrophages isolated from COPD patients showed higher expression of DPP4 than the macrophages isolated from normal subjects. In response to NTHi infection, COPD, but not normal macrophages show a further increase in the expression of DPP4. COPD macrophages also showed higher expression of IL-1ß, and CCL3 responses to NTHi than normal, and treatment with DPP4 inhibitor, diprotin A attenuated this response. To examine the contribution of DPP4 in NTHi-induced lung inflammation, COPD mice were infected with NTHi, treated with diprotin A or PBS intraperitoneally, and examined for DPP4 expression, lung inflammation, and cytokine expression. Mice with COPD phenotype showed increased expression of DPP4, which increased further following NTHi infection. DPP4 expression was primarily observed in the infiltrated inflammatory cells. NTHi-infected COPD mice also showed sustained neutrophilic lung inflammation and expression of CCL3, and this was inhibited by DPP4 inhibitor. These observations indicate that enhanced expression of DPP4 in pulmonary macrophages may contribute to sustained lung inflammation in COPD following NTHi infection. Therefore, inhibition of DPP4 may reduce the severity of NTHi-induced lung inflammation in COPD.

Evaluation of a Commercial Multiplexed Molecular Lower Respiratory Panel at a Tertiary Care Cancer Center.

Diagnosis and management of bacterial pneumonia still relies on bacterial culture and antimicrobial susceptibility testing. The Unyvero Lower Respiratory Tract panel (LRT) is a multiplex molecular assay that provides results within approximately 4.5 hours. This study evaluated the analytical performance of the LRT on bronchoalveolar lavage (BAL) fluids and bronchial washings (BW) in a cancer patient population and retrospectively determined clinical impact on therapy. Sensitivity and specificity of LRT on BAL and BW compared with bacterial culture and susceptibilities were calculated. Chart reviews were performed to determine whether antibiotic management would have changed based on the LRT results. A total of 113 BAL and 123 BW respiratory samples from 191 patients were included. The overall sensitivity and specificity were 91.7% (95% CI, 77.5%-98.3%) and 92.0% (95% CI, 87.3%-95.4%), respectively. Staphylococcus aureus was the most common target detected (n = 21) with 89.5% (95% CI, 66.8%-98.7%) sensitivity and 98.2% (95% CI, 95.4%-99.5%) specificity. Based on availability of LRT results, 4.8% of patients could have been de-escalated faster. The LRT demonstrated an overall high accuracy for the detection of common bacteria associated with pneumonia. In this cancer inpatient cohort, treatment adjustment based on LRT results would have occurred in a small number of cases. Larger studies are necessary to understand the real-world impact within specific high-risk populations.

Acute vaping exacerbates microbial pneumonia due to calcium (Ca2+) dysregulation.

As electronic cigarette (E-cig) use, also known as "vaping", has rapidly increased in popularity, data regarding potential pathologic effects are recently emerging. Recent associations between vaping and lung pathology have led to an increased need to scrutinize E-cigs for adverse health impacts. Our previous work (and others) has associated vaping with Ca2+-dependent cytotoxicity in cultured human airway epithelial cells. Herein, we develop a vaped e-liquid pulmonary exposure mouse model to evaluate vaping effects in vivo. Using this model, we demonstrate lung pathology through the use of preclinical measures, that is, the lung wet: dry ratio and lung histology/H&E staining. Further, we demonstrate that acute vaping increases macrophage chemotaxis, which was ascertained using flow cytometry-based techniques, and inflammatory cytokine production, via Luminex analysis, through a Ca2+-dependent mechanism. This increase in macrophage activation appears to exacerbate pulmonary pathology resulting from microbial infection. Importantly, modulating Ca2+ signaling may present a therapeutic direction for treatment against vaping-associated pulmonary inflammation.

Association between perioperative allogeneic red blood cell transfusion and infection after clean-contaminated surgery: a retrospective cohort study.

BACKGROUND: Allogeneic red blood cell (RBC) transfusion can induce immunosuppression, which can then increase the susceptibility to postoperative infection. However, studies in different types of surgery show conflicting results regarding this effect. METHODS: In this retrospective cohort study conducted in a tertiary referral centre, we included adult patients undergoing clean-contaminated surgery from 2014 to 2018. Patients who received allogeneic RBC transfusion from preoperative Day 30 to postoperative Day 30 were included into the transfusion group. The control group was matched for the type of surgery in a 1:1 ratio. The primary outcome was infection within 30 days after surgery, which was defined by healthcare-associated infection, and identified mainly based on antibiotic regimens, microbiology tests, and medical notes. RESULTS: Among the 8098 included patients, 1525 (18.8%) developed 1904 episodes of postoperative infection. Perioperative RBC transfusion was associated with an increased risk of postoperative infection after controlling for 27 confounders by multivariable regression analysis (odds ratio [OR]: 1.60; 95% confidence interval [CI]: 1.39-1.84; P<0.001) and propensity score weighing (OR: 1.64; 95% CI: 1.45-1.85; P<0.001) and matching (OR: 1.70; 95% CI: 1.43-2.01; P<0.001), and a dose-response relationship was observed. The transfusion group also showed higher risks of surgical site infection, pneumonia, bloodstream infection, multiple infections, intensive care admission, unplanned reoperation, prolonged postoperative length of hospital stay, and all-cause death. CONCLUSIONS: Perioperative allogeneic RBC transfusion is associated with an increased risk of infection after clean-contaminated surgery in a dose-response manner. Close monitoring of infections and enhanced prophylactic strategies should be considered after transfusion.

Pulmonary and thoracic infection by Fusobacterium nucleatum. / Infección pulmonar y torácica por Fusobacterium nucleatum.

INTRODUCTION: Fusobacterium nucleatum is an anaerobic bacillus that is part of the oral microbiota and dental pla que. This can cause local and potentially remote infections, which are exceptional in pediatrics. Ob jective: To present the case of a patient with lung injury with chest wall invasion by Fusobacterium nucleatum. CLINICAL CASE: An 11-year-old female immunocompetent patient who consulted due to a two-week history of cough, night sweats, without fever or weight loss, and increased volume at the left spleen thoracic level. There was no history of chest wall trauma or travel outside the country. Two weeks before the onset of symptoms, she was treated for dental caries. Imaging studies and CT scan showed left spleen pneumonia, which invades the pleura and the chest wall. A minimal thoracotomy was performed, releasing a thick, foul-smelling liquid. The studies for common germs and tubercu losis were negative. Hematology ruled out tumor lesions. The anaerobic study reported the develo pment of Fusobacterium nucleatum. The patient was treated with penicillin followed by amoxicillin presenting good clinical and radiological responses. The dental procedure was suspected as the cause of infection. CONCLUSIONS: Fusobacterium nucleatum can occasionally cause remote or extra-oral in fections in immunocompetent patients, such as pneumonia with chest wall invasion, therefore it is necessary to bear it in mind.

Carnobacterium inhibens isolated in blood culture of an immunocompromised, metastatic cancer patient: a case report and literature review.

BACKGROUND: Carnobacterium species are lactic acid-producing Gram-positive bacteria that have been approved by the US Food and Drug Administration and Health Canada for use as a food bio-preservative. The use of live bacteria as a food additive and its potential risk of infections in immunocompromised patients are not well understood. CASE PRESENTATION: An 81-year-old male with a history of metastatic prostate cancer on androgen deprivation therapy and chronic steroids presented to our hospital with a 2-week history of productive cough, dyspnea, altered mentation, and fever. Extensive computed tomography imaging revealed multifocal pneumonia without other foci of infection. He was diagnosed with pneumonia and empirically treated with ceftriaxone and vancomycin. Blood cultures from admission later returned positive for Carnobacterium inhibens. He achieved clinical recovery with step-down to oral amoxicillin/clavulanic acid for a total 7-day course of antibiotics. CONCLUSIONS: This is the fourth reported case of bacteremia with Carnobacterium spp. isolated from humans. This case highlights the need to better understand the pathogenicity and disease spectrum of bacteria used in the food industry for bio-preservation, especially in immunocompromised patients.

A short synthetic peptide, based on LyeTx I from Lycosa erythrognatha venom, shows potential to treat pneumonia caused by carbapenem-resistant Acinetobacter baumannii without detectable resistance.

The emergence of antibiotic-resistant bacteria, especially carbapenem-resistant Acinetobacter baumannii (CRAB), together with relative stagnation in the development of effective antibiotics, has led to enormous health and economic problems. In this study, we aimed to describe the antibacterial spectrum of LyeTx I mnΔK, a short synthetic peptide based on LyeTx I from Lycosa erythrognatha venom, against CRAB. LyeTx I mnΔK showed considerable antibacterial activity against extensively resistant A. baumannii, with minimum inhibitory and bactericidal concentrations ranging from 1 to 16 µM and 2 to 32 µM, respectively. This peptide significantly increased the release of 260 nm-absorbing intracellular material from CRAB, suggesting bacteriolysis. LyeTx I mnΔK was shown to act synergistically with meropenem and colistin against CRAB. The cytotoxic concentration of LyeTx I mnΔK against Vero cells (CC50 = 55.31 ± 5.00 µM) and its hemolytic activity (HC50 = 77.07 ± 4.00 µM) were considerably low; however, its antibacterial activity was significantly reduced in the presence of human and animal serum and trypsin. Nevertheless, the inhalation of this peptide was effective in reducing pulmonary bacterial load in a mouse model of CRAB infection. Altogether, these results demonstrate that the peptide LyeTx I mnΔK is a potential prototype for the development of new effective and safe antibacterial agents against CRAB.

Extrathoracic multiple trauma dysregulates neutrophil function and exacerbates pneumonia-induced lung injury.

BACKGROUND: Forty percent of critically ill trauma patients will develop an infectious complication. Pneumonia is the most common cause of death of trauma patients surviving their initial insult. We previously demonstrated that polytrauma (PT), defined as two or more severe injuries in at least two areas of the body, induces emergency hematopoiesis characterized by accelerated myelopoiesis in the bone marrow and increased myeloid cell frequency in the peripheral tissues. We hypothesized that PT alone induces priming of neutrophils, resulting in hyperactivation upon secondary exposure to bacteria and causing acute lung injury and increased susceptibility to secondary exposure to Pseudomonas aeruginosa pneumonia. METHODS: C57BL/6 mice were subjected to PT consisting of a lower extremity pseudofracture, liver crush injury, and 15% blood-volume hemorrhage. Pneumonia was induced by intratracheal injection of 5 × 106 CFU live P. aeruginosa or 1 × 107 of heat-killed P. aeruginosa (HKPA). For reactive oxygen species (ROS), studies polymorphonuclear neutrophils (PMNs) were isolated by immunomagnetic bead negative selection and stimulated ex-vivo with HKPA. Reactive oxygen species production was measured by immunofluorescence. For histology, lung sections were stained by hematoxylin-eosin and analyzed by a blinded grader. RESULTS: Polytrauma induced persistent changes in immune function at baseline and to secondary infection. Pneumonia after injury resulted in increased mortality (60% vs. 5% p < 0.01). Blood neutrophils from PT mice had higher resting (unstimulated) ROS production than in naive animals (p < 0.02) demonstrating priming of the neutrophils following PT. After intratracheal HKPA injection, bronchoalveolar lavage PMNs from injured mice had higher ROS production compared with naive mice (p < 0.01), demonstrating an overexuberant immunopathologic response of neutrophils following PT. CONCLUSION: Polytrauma primes neutrophils and causes immunopathologic PMN ROS production, increased lung injury and susceptibility to secondary bacterial pneumonia. These results suggest that trauma-induced immune dysfunction can cause immunopathologic response to secondary infection and suggests neutrophil-mediated pulmonary damage as a therapeutic target for posttrauma pneumonia.

52-Year-Old With Epistaxis, Hemoptysis, Hoarseness, and Weight Loss.

CLINICAL PRESENTATION: A 52-year-old man presented with hemoptysis of 2 weeks' duration. He had been experiencing hoarseness, right-sided pleuritic chest pain, subjective fevers, chills, night sweats, and 10 pounds weight loss for the previous 2 months. He additionally reported severe frontal headaches, nasal congestion, and intermittent epistaxis, which had been present for a year before his current presentation. He had worked in construction and denied tobacco or illicit drug use.

Severe pneumonia caused by Parvimonas micra: a case report.

BACKGROUND: Parvimonas micra (P. micra) is a gram-positive anaerobic coccus that is detected widely on the skin, in the oral mucosa and in the gastrointestinal tract. In certain circumstances, P. micra can cause abdominal abscesses, bacteraemia and other infections. To the best of our knowledge, there have been no case reports describing the biological characteristics of P. micra-related pneumonia. These bacteria do not always multiply in an aerobic organ, such as the lung, and they could be easily overlooked because of the clinical mindset. CASE PRESENTATION: A 35-year-old pregnant woman was admitted to the emergency department 4 weeks prior to her due date who was exhibiting 5 points on the Glasgow coma scale. A computed tomography (CT) scan showed a massive haemorrhage in her left basal ganglia. She underwent a caesarean section and brain surgery before being admitted to the ICU. She soon developed severe pneumonia and hypoxemia. Given that multiple sputum cultures were negative, the patient's bronchoalveolar lavage fluid was submitted for next-generation sequencing (NGS) to determine the pathogen responsible for the pneumonia; as a result, P. micra was determined to be the causative pathogen. Accordingly the antibiotic therapy was altered and the pneumonia improved. CONCLUSION: In this case, we demonstrated severe pneumonia caused by the anaerobic organism P. micra, and the patient benefited from receiving the correct antibiotic. NGS was used as a method of quick diagnosis when sputum culture failed to distinguish the pathogen.