Agent Of Pneumonia Research Articles

Confirmed or unconfirmed cases of 2019 novel coronavirus pneumonia in Italian patients: a retrospective analysis of clinical features

BackgroundSince December 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged as a novel etiologic agent of viral pneumonia. We aimed to compare clinical features of 165 Italian patients with laboratory confirmed or unconfirmed 2019-nCoV pneumonia.MethodsOn March 31, 2020, hospitalized patients who presented with fever and/or respiratory symptoms, exposures, and presence of lung imaging features consistent with 2019-nCoV pneumonia were included. Before admission to a hospital ward, patients underwent RT-PCR based SARS-CoV-2 RNA detection in their nasopharyngeal swab samples.ResultsOf 165 patients studied, 119 had positive RT-PCR results and 46 were RT-PCR negative for 2 days or longer (i.e., when the last swab sample was obtained). The median age was 70 years (IQR, 58–78), and 123 (74.6%) of 165 patients had at least one comorbidity. The majority of patients (101/165, 61.2%) had a mild pneumonia, and the remaining patients (64/165, 38.8%) a severe/critical pneumonia. We did not find any substantial difference in symptoms, incubation periods, and radiographic/CT abnormalities as well as in many of the biological abnormalities recorded. However, at multivariable analysis, higher concentrations of hemoglobin (OR, 1.34; 95% CI, 1.11–1.65; P = 0.003) and lower counts of leukocytes (OR, 0.81; 95% CI, 0.72–0.90; P < 0.001) were statistically associated with confirmed COVID-19 diagnosis. While mortality rates were similar, patients with confirmed diagnosis were more likely to receive antivirals (95% vs 19.6%, P < 0.001) and to develop ARDS (63% vs 37%, P = 0.003) than those with unconfirmed COVID-19 diagnosis.ConclusionsOur findings suggest that unconfirmed 2019-nCoV pneumonia cases may be actually COVID-19 cases and that clinicians should be cautious when managing patients with presentations compatible with COVID-19.

Dental setup in the covid-ified era – A review

The infectious agent of this viral pneumonia happening in Wuhan was finally identified as a novel coronavirus (2019-nCOV), the 7 member of the family of coronaviruses that infect humans widely known as Covid-19. The common transmission routes of novel coronavirus include direct transmission like cough, sneeze, and droplet inhalation transmission and contact transmission contact with oral, nasal, and eye mucous membranes. Live viruses (COVID-19) were isolated from the saliva. Hence, healthcare workers particularly the dental professionals are at more risk.An overview of how-to setup the dental office so as to minimize the risk of transmission while simultaneously carrying out the necessary treatment procedures.A proper management and setup of the dental office and treatment planning along with strict categorisation of patients is necessary for a successful and safe practice during Covid times.

Laboratory evaluation of the BioFire FilmArray Pneumonia plus panel compared to conventional methods for the identification of bacteria in lower respiratory tract specimens: a prospective cross-sectional study from South Africa

Lower respiratory tract infections are important causes of morbidity and mortality. The global increase in antimicrobial resistance necessitates rapid diagnostic assays. The BioFire FilmArray Pneumonia plus (FAPP) panel is a Food and Drug Administration-approved multiplex polymerase chain reaction assay that detects the most important etiological agents of pneumonia and associated antibiotic resistance genes, in approximately 1 hour. This study assessed the diagnostic performance of this assay by comparing it to conventional culture methods in the analysis of 59 lower respiratory tract specimens. The sensitivity and specificity of the FAPP panel for bacterial detection were 92.0% (95% confidence interval [CI], 80.8% to 97.8%) and 93.8% (95% CI, 91.1% to 95.3%) respectively. For detecting antibiotic resistance, the positive- and negative percent agreement were 100% (95% CI, 81.5% to 100.0%) and 98.5% (95% CI, 216 96.7% to 99.4%) respectively. The FAPP panel was found to be highly accurate in evaluating tracheal aspirate specimens from hospitalized patients.

A role for quercetin in coronavirus disease 2019 (COVID-19).

Several months ago, an outbreak of pneumonia of unknown aetiology was detected in Wuhan City (China) and the aetiological agent of the atypical pneumonia was isolated by the Chinese authorities as novel coronavirus (2019‐nCoV or SARS‐CoV‐2). The WHO announced this new disease was to be known as “COVID‐19.” When looking for new antiviral compounds, knowledge of the main viral proteins is fundamental. The major druggable targets of SARS‐CoV‐2 include 3‐chymotrypsin‐like protease (3CLpro), papain‐like protease (PLpro), RNA‐dependent RNA polymerase, and spike (S) protein. Quercetin inhibits 3CLpro and PLpro with a docking binding energy corresponding to −6.25 and −4.62 kcal/mol, respectively. Quercetin has a theoretical, but significant, capability to interfere with SARS‐CoV‐2 replication, with the results showing this to be the fifth best compound out of 18 candidates. On the basis of the clinical COVID‐19 manifestations, the multifaceted aspect of quercetin as both antiinflammatory and thrombin‐inhibitory actions, should be taken into consideration.

Pathogenic Effect of Prevotella intermedia on a Mouse Pneumonia Model Due to Methicillin-Resistant Staphylococcus aureus With Up-Regulated α-Hemolysin Expression.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a common causative agent of pneumonia; however, the detailed mechanism underlying severe MRSA pneumonia, including association with oral hygiene or periodontitis, remains poorly characterized. In this study, we examined the pathogenic effect of Prevotella intermedia, a major periodontopathic pathogen, on MRSA pneumonia.Methods: The pathogenic effect of the supernatant of P. intermedia (Pi Sup) was investigated in a murine MRSA pneumonia model, using several clinical strains; whereas the bactericidal activity of polymorphonuclear leukocytes (PMNs) was investigated in vitro. The effect of Pi Sup on messenger RNA (mRNA) expression of the toxin/quorum sensing system (rnaIII) was investigated by quantitative reverse transcription PCR both in vitro and in vivo.Results: Mice infected by hospital-acquired MRSA (HA-MRSA) with Pi Sup exhibited a significantly lower survival rate, higher bacterial loads in the lungs, and higher α-hemolysin (hla) expression in the lungs, than those without Pi Sup. A similar effect of Pi Sup was not observed with MRSA strains producing Panton-Valentine leucocidin (PVL) or toxic shock syndrome toxin (TSST). In vitro, Pi Sup suppressed bactericidal activity of PMNs against the HA-MRSA strain. HA-MRSA was the clinical strain with the highest ability to proliferate in the lungs and was accompanied by time-dependent up-regulation of rnaIII and hla.Conclusions: Our results provide novel evidence that the product of P. intermedia exerts a pathogenic effect on MRSA pneumonia, in particular with a strain exhibiting strong proliferation in the lower airway tract. Moreover, our results indicate that P. intermedia affects MRSA toxin expression via quorum sensing in a strain-dependent fashion, which might be important for understanding the pathogenesis of severe MRSA pneumonia.

Acute Lung Inflammation: The Crisis of Etiotropic Treatment and The Logic of Its Solutions

Modern ideas about the nature of acute inflammatory processes in the lungs are focused on the leading significance of the etiology of the disease. The predominance of this concept defines etiotropic therapy as the basis for providing medical care to this category of patients. In fact, the causative agent of acute pneumonia in most patients remains unknown or the accuracy of its diagnosis is questionable. At the same time, the targeted use of etiotropic drugs is always delayed due to the delay in the results of microbiological diagnostics. Recently, these difficulties of etiotropic therapy have been compounded by an increase in the number of patients with viral lung inflammation and the lack of effective antiviral drugs. The paradoxical and illogical nature of the situation is supplemented by a discrepancy between the intended and actual goals of diagnosis and treatment. Declaring the leading role of pathogens in the development and severity of AP, the assessment of the condition of patients and their further observation within the existing concept of views are based on signs and tests that are due to the pathogenesis of the disease and do not depend directly on its etiology. For example, a cardinal diagnostic test such as an x-ray reflects inflammatory changes in the lung tissue and their dynamics, without having absolute etiological signs. Changes in the parameters of respiration, gas exchange and hemodynamics are the result of impaired lung function as a result of inflammation, regardless of its pathogen.

Understanding Covid-19 Based on Clinical Insights and Recent Advancements in Therapeutic Discovery

An outbreak of mysterious pneumonia in December 2019 at Wuhan, China draws attention around the world. The government of Chinese and researchers employed rapid and immediate strategies to prevent and contain the outbreak. Acute Respiratory Syndrome coronavirus and the Middle East Respiratory Syndrome were found to be the causative agents of the mysterious pneumonia as a result of sequencing and etiological investigations carried out by laboratories in China. World Health Organization officially named the novel coronaviruses as COVID-19, declares it as a pandemic and potential challenge to the global health care system. This review was conducted using recent research publications from reputed journals. Since the first infected case was reported, the disease has affected more than 15 million individuals around the globe. However, there are variations on death rate base on gender, age, sex and underlining health conditions. The major symptoms of COVID-19 include: fever, headache, cough, fatigue, mild dyspnoea and sore throat. Hitherto, there is no approved drug or vaccine capable of curing COVID -19. Hitherto, physicians have been recommending the use of some FDA approved antiviral drugs such as remdesivir, chloroquine, hydroxychloroquine, glecaprevir and maraviroc which their clinical efficacy associated with the virus is still unclear. Furthermore, due to limited researches and novel approved drugs that are highly effective for COVID-19 there is a need for accelerating the on-going clinical trials to discover most effective evidence-based treatment modality to lessen the spread of this disease and prevent the burden of a future outbreak.

Establishment of a model of Mycoplasma hyopneumoniae infection using Bama miniature pigs

Mycoplasma hyopneumoniae (M. hyopneumoniae), is the primary aetiological agent of enzootic pneumonia leading to chronic respiratory disease prevalent worldwide. Conventional pigs are the only animals used for pathogenicity studies and vaccine evaluations of M. hyopneumoniae. Considering that the challenge animals have better genetic stability and a smaller body size to operate with, an alternative experimental animal model of M. hyopneumoniae infection with Bama miniature pigs was established. Nine seven-week-old snatch-farrowed, porcine colostrum-deprived (SF-pCD) Bama miniature pigs and nine conventional pigs were randomly divided into two infected groups (Bama miniature-infected (BI) and conventional-infected groups (CI), BI and CI, n = 6) and two control groups (Bama miniature control (BC) and conventional control (CC) groups, BC and CC, n = 3). Every piglet was tracheally inoculated with 5 × 108 CCU/mL containing 10% suspension of a stock of frozen lung homogenate from SF-pCD pigs infected with virulent strain JS or sterilized KM2 medium. Typical lung lesions appeared in all infected pigs after necropsy, and the mean gross lung lesions was 17.3 and 13.7 in groups of BI and CI. Serum IgG and nasal sIgA antibody titres were increased significantly. Cilia shedding and mucus staining increased greatly in JS-infected bronchi. Obvious reddish gross lesions and M. hyopneumoniae antigen were detected, especially apparently observed in group of BI. Moreover, DNA copies of M. hyopneumoniae from bronchoalveolar lavage fluid (BALF) of each JS-infected piglet reached more than 108, and M. hyopneumoniae could be re-isolated from each infected BALF. These results indicate that Bama miniature pigs could be used as an alternative and more maneuverable experimental infection model for M. hyopneumoniae and display typical clinical and pathological features consistent with those in conventional pigs.

Mycoplasma ovipneumoniae-derived lipid-associated membrane proteins induce cytokine secretion in mouse peritoneal macrophages through TLR2 signalling

BackgroundMycoplasma ovipneumoniae (M. ovi) is the causative agent of chronic non-progressive pneumonia in sheep, goats, bighorn, and wild small ruminants. However, the mechanism of infection and immune response to M. ovi remain unclear. Invading microbes express lipid-associated membrane proteins (LAMPs) on the cell surface that interact with host cells to facilitate infection, and are thus the major molecules recognised by the host immune system. Upon LAMP recognition, Toll-like receptor 2 (TLR2) and NLRP3 inflammasome sense the pathogens and signalling pathways for cytokine secretion. In this study, we investigated whether M. ovi and M. ovi-derived LAMPs are immuno-biologically active compounds capable of activating mouse peritoneal macrophages and explored the underlying mechanism. ResultsAfter infection of wild-type mice with M. ovi, the expression of TLR2 and NLRP3 at the transcriptional and translational levels was determined with reverse transcription-polymerase chain reaction and flow cytometry. In addition, the cytokine levels and associated pathways were detected in infected wild-type, Tlr2−/−, and Nlrp3−/− mice via enzyme-linked immunosorbent assays and western blotting. The nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signalling pathways were found to mediate the expression of inflammatory cytokines in M. ovi or M. ovi-derived LAMP-infected peritoneal macrophages, and cytokines were not induced in Tlr2−/− and/or Nlrp3−/− macrophages. ConclusionHost cytokine production is activated in response to M. ovi-derived LAMPs through the NF-κB and MAPK signalling pathway via TLR2.

Gram-negative bacteria as causative agents of ventilator-associated pneumonia and their respective resistance mechanisms

Ventilator-associated pneumonia (VAP) is a serious and common complication in patients admitted to intensive care unit (ICU) and contributes to mortality. Multidrug Gram-negative bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae are frequently associated with VAP in ICU. A prospective study was set up in three ICUs of the University Hospital Center Zagreb and one ICU in General Hospital Pula from September 2017 to March 2018. Antibiotic susceptibility was determined by broth microdilution method. Production of extended-spectrum β-lactamases (ESBLs) was determined by double-disk synergy test and carbapenemases by Hodge and carbapenem inactivation method (CIM). The genes encoding ESBLs, carbapenemases of class A, B and D and qnr genes were determined by PCR. In total 97 Gram-negative bacteria isolates were analyzed. P. aeruginosa demonstrated high resistance rates for imipenem and meropenem with 74% and 68% of resistant strains, respectively. Moderate resistance rates were observed for ceftazidime andpiperacillin/tazobactam, ciprofloxacin and gentamicin (44%). All except three A. baumannii isolates, were resistant to carbapenems and to all other antibiotics apart from colistin and amikacin. Eight A. baumannii isolates were positive for blaOXA-23 and 12 for blaOXA-24 genes. Four K. pneumoniae and two E. cloacae strains were ESBL positive and harboured group 1 of CTX-M β-lactamases. Three P. mirabilis strains were positive for plasmid-mediated ampC β-lactamase of CMY family. Two carbapenem-resistant K. pneumoniae harboured OXA-48 and one carbapenem-resistant E. cloacae VIM-1. A high proportion of multidrug-resistant P. aeruginosa, K. pneumoniae and extensively resistant A. baumannii was reported. Acquired resistance mechanisms, mainly production of carbapenemases and ESBLs were dominant in A. baumannii and K. pneumoniae, respectively. Resistance of P. aeruginosa isolates was more likely due to upregulation of efflux pumps or porin loss. A marked diversity of β-lactamases was identified in Enterobacteriaceae.

Nasopharyngeal Carriage of Streptococcus pneumoniae and Associated Factors among Children in Southwest Ethiopia

Background: In Ethiopia, Streptococcus pneumoniae is the predominant causative agent of pneumonia. About, 95% of bacterial pneumonia cases in under five years of children are caused by pneumococci. Objective: To assess the nasopharyngeal carriage of Streptococcus pneumoniae, its antibiotic susceptibility pattern, and associated factors among children in Southwest Ethiopia. Methods: A cross-sectional study was conducted from October 01, 2018, to December 30, 2018. A total of 293 children aged ≤15 years were included in the study using a systematic random sampling technique. A nasopharyngeal swab was collected using a sterile cotton swab and cultured on blood agar supplemented with 5μg/ml gentamicin. The antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion technique. Results: The ages of participants ranged from 5 months to 14 years. The carriage rate of Streptococcus pneumoniae was 74/293 (25.3%). Being within the age group &lt;3 years, the habit of sleeping with parent(s)/guardians and numbers of rooms per household were significantly associated with pneumococcal carriage. Streptococcus pneumoniae showed the highest resistance to Tetracycline, 36 (48.65%), and Trimethoprim/sulfamethoxazole, 29 (39.2%), and was found to be susceptible to Chloramphenicol, 54 (77%), and Erythromycin, 38 (51.4%). Conclusion: The nasopharyngeal carriage rate of Streptococcus pneumoniae is considerably high. High antimicrobial resistance of Streptococcus pneumoniae against Tetracycline and Trimethoprim/sulfamethoxazole was observed. Living in a house with a single room, children’s habit of sleeping with parents/guardians and age are associated factors of high pneumococcal carriage. Strategies need to be designed to address the modifiable associated factors and the bacterium antibiotic resistance pattern should be monitored regularly.

Need for Abundant Caution in Prophylactic Application of Chloroquine and Hydroxychloroquine for Viral Infections Including COVID-19: Possibility of Increased Susceptibility

Significant interest in application of Chloroquine (CQ) and Hydroxychloroquine (HCQ) for prophylaxis and treatment of COVID-19 has been recently reported throughout the world. In the light of this, it has become important to revisit the mechanisms of action, as well as clinical evidence for efficacy of CQ and HCQ in similar viral infections. We note that while some evidence exists for therapeutic efficacy of CQ and HCQ in mitigating morbidities associated with virus-induced inflammation and immuno-hyperactivity, abundant caution is necessary in expecting prophylactic efficacy in the light of therapeutic evidence. In particular, we intend to draw urgent attention to the fact that the same immuno-suppresive and immuno-modulatory properties of CQ and HCQ which render them useful as therapeutic agents in viral pneumonia and cytokine storm syndrome, are also expected to make them dangerous prophylactic agents against viral infections. We also intend to draw attention to some other potential concerns associated with widespread prophylactic usage of CQ and HCQ.

Seroprevalence of IgM Antibody in Atypical Pneumonia Causing Pathogens by Pneumoslide, IFA

Background: Atypical bacterial and viral pathogens play an important role in atypical pneumonia are responsible for one of the leading causes of morbidity and mortality, particularly in developing countries.&#x0D; Objective: The purpose of this study to determine the prevalence of bacterial and viral pathogens causing acute atypical pneumonia in different age groups and seasonality patterns of prevalence in India.&#x0D; Methods: This retrospective study was conducted on 680 samples tested during December 2018 to August 2019, performed at Microbiology department of Dr. Lal Path Labs. Serum samples were used for Pneumoslide IgM test diagnose 9 Atypical bacterial &amp; viral pathogens: Legionella pneumophila (LP), Mycoplasma pneumoniae (MP), Coxiella burnetti (COX), Chlamydophila pneumonia (CP) Adenovirus (ADV), Respiratory syncytial virus (RSV) Influenza A (INFA), Influenza B (INFB), Parainfluenza serotypes 1,2 &amp;3(PIVs).&#x0D; Results: Of a total 477(70.1%) samples were positive for atypical pneumonia pathogens. Atypical pneumonia was seen in extremes of age ie: &lt;=5 years and &gt;60 elderly adults without much of a gender bias. Co infections was seen in 62.1%. Legionella pneumophila (42.5%) was the dominant pathogen followed by Influenza B (41.7%) Mycoplasma pneumoniae (33.4%), Parainfluenza serotypes 1,2 &amp;3 (29.4%) respectively. Atypical pneumonia has a spring predominance that is peaking in March.&#x0D; Conclusion: Among six predominant atypical pathogens, Legionella pneumophila and Influenza B was most predominant pathogens, as a causative agent of atypical pneumonia followed by Mycoplasma pneumoniae seen mostly in young (0-5 years) comparison to all age groups. Hence, Pneumoslide IgM as a multi panel test needed to ensure initiation of targeted therapy. Pneumoslide IgM, by IFA is a rapid, cost effective easy to identify &amp; classify atypical pneumonia causing pathogens.

Neutralizing epitope of the Fusion Protein of Respiratory Syncytial Virus Embedded in the HA Molecule of LAIV Virus is not Sufficient to Prevent RS Virus Pulmonary Replication but Ameliorates Lung Pathology following RSV Infection in Mice

Aims:To develop experimental bivalent vaccines against influenza and RSV using a cold-adapted LAIV backbone.Background:Respiratory syncytial virus (RSV) is a causative agent of bronchiolitis and pneumonia in young children, elderly and immunocompromised adults. No vaccine against RSV has been licensed to date for various reasons. One of the promising platforms for designing RSV vaccine is the use of live attenuated influenza vaccine (LAIV) viruses to deliver RSV epitopes to the respiratory mucosa.Objective:To generate recombinant LAIV viruses encoding a neutralizing epitope of the RSV fusion protein and assess their protective potential against both influenza and RSV infections in a mouse model.Methods:Reverse genetics methods were used to rescue recombinant LAIV+HA/RSV viruses expressing chimeric hemagglutinins encoding the RSV-F epitope at its N-terminus using two different flexible linkers. BALB/c mice were intranasally immunized with two doses of the recombinant viruses and then challenged with the influenza virus or RSV. The LAIV viral vector and formalin-inactivated RSV (FI-RSV) were included as control vaccines. Protection was assessed by the reduction of virus pulmonary titers. In addition, RSV-induced lung pathology was evaluated by histopathology studies.Results:Two rescued chimeric LAIV+HA/RSV viruses were identical to the LAIV vector in terms of replication capacityin vitroandin vivo. The RSV-F neutralizing epitope was successfully expressed only if inserted into the HA molecule via G-linker, but not A-linker. Both chimeric viruses induced high influenza-specific antibody levels and fully protected mice against a lethal influenza challenge virus. However, they induced weak anti-RSV antibody responses which did not prevent RS virus replication upon challenge, and only LAIV-HA+G-RSV variant protected mice against RSV-induced lung pathology.Conclusion:Although the designed LAIV-RSV chimeric viruses were unable to neutralize the RS virus pulmonary replication, the LAIV-HA+G-RSV reduced RSV-induced lung pathology and can be considered a promising bivalent vaccine against influenza and RSV infections and warrants its further development.

Isolation and characterization of mammalian orthoreoviruses using a cell line resistant to sapelovirus infection.

Porcine sapelovirus (PSV) is a causative agent of acute diarrhoea, pneumonia and reproductive disorders in swine. Since PSV infection interrupts the growth of other viruses due to its high replication capability in cell culture, the prevention of PSV replication is a keystone to the isolation of non-PSV agents from PSV-contaminated samples. In the present study, we established the PSV infection-resistant cell line N1380 and isolated three mammalian orthoreoviruses (MRV) strains, sR1521, sR1677 and sR1590, from swine in Taiwan. These Taiwanese isolates induced an extensive cytopathic effect in N1380 cells upon infection. The complete and empty virus particles were purified from the cell culture supernatants. Next-generation sequencing analyses revealed that the complete virus particles contained 10 segments, including 3 large (L1, L2 and L3), 3 medium (M1, M2 and M3) and 4 small (S1, S2, S3 and S4) segments. In contrast, the empty virus particles without genome were non-infectious. Phylogenetic analyses revealed that the Taiwanese strains belong to serotype 2 MRV (MRV2). We established an ELISA for the detection of IgG antibody against MRV2 by using the empty virus particles as the antigen. A total of 540 swine and 95 wild boar serum samples were collected in Japan, and the positive rates were 100% and 52.6%, respectively. These results demonstrated that MRV infection occurred frequently in both swine and wild boar in Japan. We established a cell line that is efficient for the isolation of MRV, and the ELISA based on the naturally occurring empty particles would be of great value for the surveillance of MRV-related diseases.

Fundamental Basis of COVID-19 Pathogenesis

Abstract At the end of 2019, a new coronavirus infection occurred in the People’s Republic of China with an epicentre in the city of Wuhan. On February 11th, 2020, the World Health Organization assigned the official name of the infection caused by the new coronavirus – COVID-19. COVID-19 has affected people from all over the world given that the infection was noted in 200 countries resulting in annunciation of the pandemic situation. Human corona viruses cause mild to moderate respiratory infections. At the end of 2002, a new coronavirus appeared (SARS-CoV), the causal agent of atypical pneumonia, which caused acute respiratory distress syndrome (ARDS). The initial stage of COVID-19 infection is the penetration of SARS-CoV-2 into target cells that have angiotensin converting enzyme type II receptors. The virus enters the body through the respiratory tract and interacts primarily with toll-like receptors (TLRs). The events in SARS-Cov-2 induced infection follow the next scenario: epithelial cells via TLRs recognize and identify SARS-Cov-2, and after that the information is transmitted to the transcriptional NF-κB, which causes expression of the corresponding genes. Activated in this way, the epithelial cells begin to synthesize various biologically active molecules. The results obtained on preclinical material indicate that ROS generation increases and the antioxidant protection decreases, which plays a major role in the pathogenesis of SARS-CoV, as well as in the progression and severity of this respiratory disease.

Peculiarities of bacterial agents of pneumonia in HIV-infected patients. Preventive measures for pulmonary infections in immunocompromised patients (literature review)

The problem of HIV infection in Russia remains topical, despite the active prevention and use of antiretroviral therapy. The main causes of hospitalization and lethal outcome among HIV patients are respiratory diseases, community-acquired pneumonia in particular. This article analyzes the literature data on causative agents of pneumonia in HIV-positive patients, the possibility to vaccinate such patients and its effectiveness.

A study to assess the magnitude of atypical pneumonia by serum polymerase chain reaction in children aged 3 years to 18 years at Kempegowda Institute of Medical Sciences hospital, Bengaluru, Karnataka, India

Background: Atypical organisms are a common causative agent of pneumonia in children more than 3 years of age, causing around 10-30% of the cases. Though atypical pathogens are said to cause relatively milder form of pneumonia as compared to other bacterial and viral pathogens, severe manifestations can also occur. Early identification of these pathogens can help in starting treatment with macrolides, which can reduce the length of hospital stay and mortality. Hence in this study the prevalence of atypical organisms was identified by using serum Polymerase chain reaction (PCR).Methods: This was a prospective observational study conducted in children between 3 years to 18 years of age with clinical diagnosis of pneumonia admitted in wards and PICU in KIMS hospital. Authors excluded Immunocompromised children. Detailed history and clinical examination was done. Investigations - complete hemogram, Chest Xray, blood Culture and sensitivity and serum PCR was done for a sample size of 100 children.Results: In this study among the three atypical organisms, Legionella pneumoniae was identified in 2% of the cases by serum PCR.Conclusions: In this study among the three atypical pathogens authors could only identify Legionella pneumoniae. Prevalence of Legionella pneumoniae was 2%. While treating children aged 3 years to 18 years with pneumonia, a high degree of suspicion of atypical pathogens is required, especially in Legionella because of its high mortality rate. In such circumstances adding macrolides along with other antibiotics will be beneficial to the patients outcome and duration of hospital stay.

Identification of a novel TLR5 agonist derived from the P97 protein of Mycoplasma hyopneumoniae.

By modulating specific immune responses against antigens, adjuvants are used in many vaccine preparations to enhance protective immunity. The C-terminal domain of the protein P97 (P97c) of Mycoplasma hyopneumoniae, which is the etiologic agent of porcine enzootic pneumonia, has been shown to increase the specific humoral response against an antigen when this antigen is merged with P97c and delivered by adenovectors. However, the immunostimulating mechanism of this protein remains unknown. In the present study, recombinantly expressed P97c triggered a concentration-dependent TLR5 activation and stimulates the production of interleukin-8 from HEK-Blue mTLR5 cells. Circular dichroism spectroscopy and prediction of 3-dimensional conformation exposed a relevant secondary and tertiary structural homology between P97c and flagellin, the known potent TLR5 agonist. P97c adjuvanticity was evaluated by fusing the conserved epitope of the ectodomain matrix 2 protein (M2e) of the influenza A virus to the protein. Mice immunized with P97c-3M2e revealed a high antibody titer against the M2e epitope associated with a mixed Th1/Th2 immune response. Overall, this study identifies a novel agonist of the pattern recognition receptor TLR5 and reveals that P97c is a potential adjuvant through the activation of the innate immune system.

Mycoplasma pneumoniae biofilms grown in vitro: traits associated with persistence and cytotoxicity.

The atypical bacterial pathogen Mycoplasma pneumoniae is a leading etiological agent of community-acquired pneumonia in humans; infections are often recalcitrant, recurrent and resistant to antibiotic treatment. These characteristics suggest a mechanism that facilitates long-term colonization in hosts. In an in vitro setting, M. pneumoniae forms biofilms that are unusual in that motility plays no more than a very limited role in their formation and development. Given the unusual nature of M. pneumoniae biofilms, open questions remain concerning phenotypes associated with persistence, such as what properties might favour the bacteria while minimizing host damage. M. pneumoniae also produces several cytotoxic molecules including community-acquired respiratory distress syndrome (CARDS) toxin, H2S and H2O2, but how it deploys these agents during growth is unknown. Whereas several biochemical techniques for biofilm disruption were ineffective, sonication was required for disruption of M. pneumoniae biofilms to generate individual cells for comparative studies, suggesting unusual physical properties likely related to the atypical cell envelope. Nonetheless, like for other bacteria, biofilms were less susceptible to antibiotic inhibition and complement killing than dispersed cells, with resistance increasing as the biofilms matured. CARDS toxin levels and enzymatic activities associated with H2S and H2O2 production were highest during early biofilm formation and decreased over time, suggesting attenuation of virulence in connection with chronic infection. Collectively, these findings result in a model of how M. pneumoniae biofilms contribute to both the establishment and propagation of M. pneumoniae infections, and how both biofilm towers and individual cells participate in persistence and chronic disease.