Bacterial Respiratory Pathogens Research Articles

Inhalational Gentamicin Treatment Is Effective Against Pneumonic Plague in a Mouse Model.

Pneumonic plague is an infectious disease characterized by rapid and fulminant development of acute pneumonia and septicemia that results in death within days of exposure. The causative agent of pneumonic plague, Yersinia pestis (Y. pestis), is a Tier-1 bio-threat agent. Parenteral antibiotic treatment is effective when given within a narrow therapeutic window after symptom onset. However, the non-specific “flu-like” symptoms often lead to delayed diagnosis and therapy. In this study, we evaluated inhalational gentamicin therapy in an infected mouse model as a means to improve antibiotic treatment efficacy. Inhalation is an attractive route for treating lung infections. The advantages include directly dosing the main infection site, the relative accessibility for administration and the lack of extensive enzymatic drug degradation machinery. In this study, we show that inhalational gentamicin treatment administered 24 h post-infection, prior to the appearance of symptoms, protected against lethal intranasal challenge with the fully virulent Y. pestis Kimberley53 strain (Kim53). Similarly, a high survival rate was demonstrated in mice treated by inhalation with another aminoglycoside, tobramycin, for which an FDA-approved inhaled formulation is clinically available for cystic fibrosis patients. Inhalational treatment with gentamicin 48 h post-infection (to symptomatic mice) was also successful against a Y. pestis challenge dose of 10 i.n.LD50. Whole-body imaging using IVIS technology demonstrated that adding inhalational gentamicin to parenteral therapy accelerated the clearance of Y. pestis from the lungs of infected animals. This may reduce disease severity and the risk of secondary infections. In conclusion, our data suggest that inhalational therapy with aerosolized gentamicin may be an effective prophylactic treatment against pneumonic plague. We also demonstrate the benefit of combining this treatment with a conventional parenteral treatment against this rapidly progressing infectious disease. We suggest the inhalational administration route as a clinically relevant treatment modality against pneumonic plague and other respiratory bacterial pathogens.

Bacillus licheniformis in geogenic dust induces inflammation in respiratory epithelium

Exposure to environmental geogenic (or earth-derived) dust can lead to more frequent and severe infections in the human airway. Particulate matter < 10 µm (PM10) is the component of air pollution that is commonly associated with the exacerbation of respiratory diseases. We have previously demonstrated that mice exposed to geogenic dust PM10 experienced an exacerbation of inflammatory responses to influenza A virus. Whether geogenic dust PM10 also exacerbates respiratory bacterial infection is not yet known, nor are the components of the dust that drive these responses.We treated airway bronchial epithelial cells (NuLi-1) with UV-irradiated geogenic dust PM10 from six remote Western Australian towns. High levels of IL-6 and IL-8 production were observed, as well as persistent microbial growth. 16 S rRNA sequencing of the growth identified the microbe as Bacillus licheniformis, a spore-forming, environmentally abundant bacterium. We next investigated the interaction of B. licheniformis with respiratory epithelium in vitro to determine whether this exacerbated infection with a bacterial respiratory pathogen (non-typeable Haemophilus influenzae, NTHi).Heat treatment (100 °C) of all PM10 samples eliminated B. licheniformis contamination and reduced epithelial inflammatory responses, suggesting that heat-labile and/or microbial factors were involved in the host response to geogenic dust PM10. We then exposed NuLi-1 epithelium to increasing doses of the isolated Bacillus licheniformis (multiplicity of infection of 10:1, 1:1 or 0.1:1 bacteria: cells) for 1, 3, and 24 h. B. licheniformis and NTHi infection (association and invasion) was assessed using a standard gentamicin survival assay, and epithelial release of IL-6 and IL-8 was measured using a bead based immunoassay.B. licheniformis was cytotoxic to NuLi-1 cells at 24 h. At 3 h post-challenge, B. licheniformis elicited high IL-6 and IL-8 inflammatory responses from NuLi-1 cells compared with cells treated with heat-treated geogenic dust PM10 (p < 0.0001). Whilst treatment of cells with B. licheniformis increased inflammation, this did not make the cells more susceptible to NTHi infection. This study highlights that geogenic dust PM10 can harbour viable bacterial spores that induce inflammation in respiratory epithelium. The impact on respiratory health from inhalation of bacterial spores in PM10 in arid environments may be underestimated. Further investigation into the contribution of B. licheniformis and the wider dust microbiome to respiratory infection is warranted.

Microbial co-infection alters macrophage polarization, phagosomal escape, and microbial killing

Macrophages are important innate immune cells that respond to microbial insults. In response to multi-bacterial infection, the macrophage activation state may change upon exposure to nascent mediators, which results in different bacterial killing mechanism(s). In this study, we utilized two respiratory bacterial pathogens, Mycobacterium bovis (Bacillus Calmette Guẻrin, BCG) and Francisella tularensis live vaccine strain (LVS) with different phagocyte evasion mechanisms, as model microbes to assess the influence of initial bacterial infection on the macrophage response to secondary infection. Non-activated (M0) macrophages or activated M2-polarized cells (J774 cells transfected with the mouse IL-4 gene) were first infected with BCG for 24–48 h, subsequently challenged with LVS, and the results of inhibition of LVS replication in the macrophages was assessed. BCG infection in M0 macrophages activated TLR2-MyD88 and Mincle-CARD9 signaling pathways, stimulating nitric oxide (NO) production and enhanced killing of LVS. BCG infection had little effect on LVS escape from phagosomes into the cytosol in M0 macrophages. In contrast, M2-polarized macrophages exhibited enhanced endosomal acidification, as well as inhibiting LVS replication. Pre-infection with BCG did not induce NO production and thus did not further reduce LVS replication. This study provides a model for studies of the complexity of macrophage activation in response to multi-bacterial infection.

Comparison of treatment history and antimicrobial sensitivity results of common bovine respiratory disease bacterial pathogens from cases submitted to the ISU-VDL from 2013-2015

Summarized susceptibility results from diagnostic laboratory cases are often used to evaluate trends in antibiotic resistance. The objective of this retrospective study was to evaluate summarized antimicrobial susceptibility data from bovine respiratory disease cases submitted to the Iowa State University Veterinary Diagnostic Laboratory in the context of reported antibiotic treatment history.

Detection of respiratory bacterial pathogens causing atypical pneumonia by multiplex Lightmix® RT-PCR

Pneumonia is a severe infectious disease. In addition to common viruses and bacterial pathogens (e.g. Streptococcus pneumoniae), fastidious respiratory pathogens like Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella spp. can cause severe atypical pneumonia. They do not respond to penicillin derivatives, which may cause failure of antibiotic empirical therapy. The same applies for infections with B. pertussis and B. parapertussis, the cause of pertussis disease, that may present atypically and need to be treated with macrolides. Moreover, these fastidious bacteria are difficult to identify by culture or serology, and therefore often remain undetected. Thus, rapid and accurate identification of bacterial pathogens causing atypical pneumonia is crucial. We performed a retrospective method evaluation study to evaluate the diagnostic performance of the new, commercially available Lightmix® multiplex RT-PCR assay that detects these fastidious bacterial pathogens causing atypical pneumonia. In this retrospective study, 368 clinical respiratory specimens, obtained from patients suffering from atypical pneumonia that have been tested negative for the presence of common agents of pneumonia by culture and viral PCR, were investigated. These clinical specimens have been previously characterized by singleplex RT-PCR assays in our diagnostic laboratory and were used to evaluate the diagnostic performance of the respiratory multiplex Lightmix® RT-PCR. The multiplex RT-PCR displayed a limit of detection between 5 and 10 DNA copies for different in-panel organisms and showed identical performance characteristics with respect to specificity and sensitivity as in-house singleplex RT-PCRs for pathogen detection. The Lightmix® multiplex RT-PCR assay represents a low-cost, time-saving and accurate diagnostic tool with high throughput potential. The time-to-result using an automated DNA extraction device for respiratory specimens followed by multiplex RT-PCR detection was below 4 h, which is expected to significantly improve diagnostics for atypical pneumonia-associated bacterial pathogens.

Multicenter Evaluation of the ePlex Respiratory Pathogen Panel for the Detection of Viral and Bacterial Respiratory Tract Pathogens in Nasopharyngeal Swabs

ABSTRACTThe performance of the new ePlex Respiratory Pathogen (RP) panel (GenMark Diagnostics) for the simultaneous detection of 19 viruses (influenza A virus; influenza A H1 virus; influenza A 2009 H1 virus; influenza A H3 virus; influenza B virus; adenovirus; coronaviruses [HKU1, OC43, NL63, and 229E]; human rhinovirus/enterovirus; human metapneumovirus; parainfluenza viruses 1, 2, 3, and 4; and respiratory syncytial virus [RSV] [RSV subtype A and RSV subtype B]) and 2 bacteria (Mycoplasma pneumoniae and Chlamydia pneumoniae) was evaluated. Prospectively and retrospectively collected nasopharyngeal swab (NPS) specimens (n = 2,908) were evaluated by using the ePlex RP panel, with the bioMérieux/BioFire FilmArray Respiratory Panel (BioFire RP) as the comparator method. Discordance analysis was performed by using target-specific PCRs and bidirectional sequencing. The reproducibility of the assay was evaluated by using reproducibility panels comprised of 6 pathogens. The overall agreement between the ePlex RP and BioFire RP results was >95% for all targets. Positive percent agreement with the BioFire RP result for viruses ranged from 85.1% (95% confidence interval [CI], 80.2% to 88.9%) to 95.1% (95% CI, 89.0% to 97.9%), while negative percent agreement values ranged from 99.5% (95% CI, 99.1% to 99.7%) to 99.8% (95% CI, 99.5% to 99.9%). Additional testing of discordant targets (12%; 349/2,908) confirmed the results of ePlex RP for 38% (131/349) of samples tested. Reproducibility was 100% for all targets tested, with the exception of adenovirus, for which reproducibilities were 91.6% at low virus concentrations and 100% at moderate virus concentrations. The ePlex RP panel offers a new, rapid, and sensitive “sample-to-answer” multiplex panel for the detection of the most common viral and bacterial respiratory pathogens.

Respiratory explants as a model to investigate early events of contagious bovine pleuropneumonia infection

Contagious bovine pleuropneumonia (CBPP) is a severe disease caused by Mycoplasma mycoides subsp. mycoides (Mmm). Knowledge on CBPP pathogenesis is fragmented and hampered by the limited availability of laboratory animal and in vitro models of investigation. The purpose of the present study is to assess respiratory explants as useful tools to study the early stages of CBPP. Explants were obtained from trachea, bronchi and lungs of slaughtered cattle, tested negative for Mycoplasma spp. and for the major bacterial and viral respiratory pathogens. The interaction of Mmm with explant cells was studied by immunohistochemistry (IHC), double-labelling indirect immunofluorescence (DLIIF) and laser scanning confocal microscopy (LSCM). Mmm capability to survive and proliferate within the explants was evaluated by standard microbiological procedures. Finally, the putative cellular internalization of Mmm was further investigated by the gentamicin invasion assay. IHC and DLIIF indicated that Mmm can colonize explants, showing a marked tropism for lower airways. Specifically, Mmm was detected on/inside the bronchiolar and alveolar epithelial cells, the alveolar macrophages and the endothelial cells. The interaction between Mmm and explant cells was abolished by the pre-incubation of the pathogen with bovine anti-Mmm immune sera. Mmm was able to survive and proliferate in all tracheal, bronchial and lung explants, during the entire time course of the experiments. LSCM and gentamicin invasion assay both confirmed that Mmm can enter non-phagocytic host cells. Taken together, our data supports bovine respiratory explants as a promising tool to investigate CBPP, alternative to cattle experimental infection.

Detection of Pathogen Exposure in African Buffalo Using Non-Specific Markers of Inflammation.

Detecting exposure to new or emerging pathogens is a critical challenge to protecting human, domestic animal, and wildlife health. Yet, current techniques to detect infections typically target known pathogens of humans or economically important animals. In the face of the current surge in infectious disease emergence, non-specific disease surveillance tools are urgently needed. Tracking common host immune responses indicative of recent infection may have potential as a non-specific diagnostic approach for disease surveillance. The challenge to immunologists is to identify the most promising markers, which ideally should be highly conserved across pathogens and host species, become upregulated rapidly and consistently in response to pathogen invasion, and remain elevated beyond clearance of infection. This study combined an infection experiment and a longitudinal observational study to evaluate the utility of non-specific markers of inflammation [NSMI; two acute phase proteins (haptoglobin and serum amyloid A), two pro-inflammatory cytokines (IFNγ and TNF-α)] as indicators of pathogen exposure in a wild mammalian species, African buffalo (Syncerus caffer). Specifically, in the experimental study, we asked (1) How quickly do buffalo mount NSMI responses upon challenge with an endemic pathogen, foot-and-mouth disease virus; (2) for how long do NSMI remain elevated after viral clearance and; (3) how pronounced is the difference between peak NSMI concentration and baseline NSMI concentration? In the longitudinal study, we asked (4) Are elevated NSMI associated with recent exposure to a suite of bacterial and viral respiratory pathogens in a wild population? Among the four NSMI that we tested, haptoglobin showed the strongest potential as a surveillance marker in African buffalo: concentrations quickly and consistently reached high levels in response to experimental infection, remaining elevated for almost a month. Moreover, elevated haptoglobin was indicative of recent exposure to two respiratory pathogens assessed in the longitudinal study. We hope this work motivates studies investigating suites of NSMI as indicators for pathogen exposure in a broader range of both pathogen and host species, potentially transforming how we track disease burden in natural populations.

Bacterial co-infection and early mortality among pulmonary tuberculosis patients in Manila, The Philippines.

To investigate the prevalence of bacterial co-infection and its effect on early mortality among hospitalised human immunodeficiency virus (HIV) negative pulmonary tuberculosis (PTB) patients in Manila, the Philippines. A prospective observational study was conducted at a national infectious disease hospital. HIV-negative PTB patients aged 13 years hospitalised from November to December 2011 and from December 2012 to May 2013 were enrolled. Sputum samples were tested for Mycobacterium tuberculosis and six respiratory bacterial pathogens using polymerase chain reaction (PCR). Of 466 patients, 228 (48.9%) were TB-PCR-positive. Overall, bacterial pathogens in purulent sputum were detected in 135 (29.0%) patients: Haemophilus influenzae was the most common bacterium (21.2%), followed by Streptococcus pneumoniae (7.9%). The prevalence of bacterial co-infection did not differ between TB-PCR-positive and -negative patients. A total of 92 (19.7%) patients died within 2 weeks. Bacterial co-infection was significantly associated with an increased risk of 2-week mortality among TB-PCR-positive patients (adjusted risk ratio [aRR] 1.67, 95%CI 1.03-2.72). This association was also observed but did not reach statistical significance among TB-PCR-negative patients (aRR1.7, 95%CI 0.95-3.02). Bacterial co-infection is common and contributes to an increased risk of early mortality among HIV-negative PTB patients.

NLRP3 Is a Critical Regulator of Inflammation and Innate Immune Cell Response during Mycoplasma pneumoniae Infection.

Mycoplasma pneumoniae is an atypical bacterial respiratory pathogen known to cause a range of airway inflammation and lung and extrapulmonary pathologies. We recently reported that an M. pneumoniae-derived ADP-ribosylating and vacuolating toxin called community-acquired respiratory distress syndrome (CARDS) toxin is capable of triggering NLRP3 (NLR-family, leucine-rich repeat protein 3) inflammasome activation and interleukin-1β (IL-1β) secretion in macrophages. However, it is unclear whether the NLRP3 inflammasome is important for the immune response during M. pneumoniae acute infection. In the current study, we utilized in vitro and in vivo models of M. pneumoniae infection to characterize the role of the NLRP3 inflammasome during acute infection. M. pneumoniae-infected macrophages deficient for inflammasome components NLRP3, ASC (apoptosis speck-like protein containing a caspase activation and recruitment domain), or caspase-1 failed to process and secrete IL-1β. The MyD88/NF-κB signaling pathway was found to be critical for proinflammatory gene expression in macrophages infected with M. pneumoniae C57BL/6 mice deficient for NLRP3 expression were unable to produce IL-1β in the airways during acute infection, and lack of this inflammatory response led to deficient immune cell activation and delayed bacterial clearance. These findings are the first to report the importance of the NLRP3 inflammasome in regulating the inflammatory response and influencing the progression of M. pneumoniae during acute infection.

Dynamics of Bacterial Colonization With Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis During Symptomatic and Asymptomatic Viral Upper Respiratory Tract Infection.

BackgroundVirus is detected in about 80% of upper respiratory tract infections (URTIs) in children and is also detectable in the nasopharynx of 30% of asymptomatic children. The effect of asymptomatic viral infection on the dynamics of bacterial density and colonization of the nasopharynx has not been reported. The current study was performedto assess the presence and density of Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in the nasopharynx of 4–7-year-old children during URTI and when well.MethodsNasal samples were obtained during 4 surveillance periods when children were asymptomatic and whenever they had symptoms of URTI. Respiratory viruses and bacterial pathogens were identified and quantified using polymerase chain reaction.ResultsThe proportion of children colonized with all 3 bacteria was higher during visits for acute URTI than during asymptomatic surveillance visits. Mean bacterial densities were significantly higher at all visits for all 3 pathogens when a virus was detected. The differences between the means were 1.0, 0.4, and 0.7 log10 colony-forming unit equivalents per milliliter for S. pneumoniae, H. influenzae, and M. catarrhalis, respectively, compared with visits in which virus was not detected. The percentage of children colonized and density were also higher at asymptomatic visits in which virus was detected than at visits in which virus was not detected.ConclusionThe density and frequency of colonization with S. pneumoniae, H. influenzae, and M. catarrhalis in nasal wash samples increase during periods of both symptomatic and asymptomatic viral infection. Increases in bacterial colonization observed during asymptomatic viral infection were nearly the same magnitude as when children were symptomatic.

Update on Actinobacillus pleuropneumoniae-knowledge, gaps and challenges.

Porcine pleuropneumonia, caused by the bacterial porcine respiratory tract pathogen Actinobacillus pleuropneumoniae, leads to high economic losses in affected swine herds in most countries of the world. Pigs affected by peracute and acute disease suffer from severe respiratory distress with high lethality. The agent was first described in 1957 and, since then, knowledge about the pathogen itself, and its interactions with the host, has increased continuously. This is, in part, due to the fact that experimental infections can be studied in the natural host. However, the fact that most commercial pigs are colonized by this pathogen has hampered the applicability of knowledge gained under experimental conditions. In addition, several factors are involved in development of disease, and these have often been studied individually. In a DISCONTOOLS initiative, members from science, industry and clinics exchanged their expertise and empirical observations and identified the major gaps in knowledge. This review sums up published results and expert opinions, within the fields of pathogenesis, epidemiology, transmission, immune response to infection, as well as the main means of prevention, detection and control. The gaps that still remain to be filled are highlighted, and present as well as future challenges in the control of this disease are addressed.

A vapour phase assay for evaluating the antimicrobial activities of essential oils against bovine respiratory bacterial pathogens.

In this study, we present a new vapour phase assay for evaluating the antimicrobial activities of essential oils (EO) against bovine respiratory pathogens (BRPs). Using this assay, we identified EOs, such as ajowan, thyme and cinnamon leaf, that can effectively inhibit growth of the BRPs Mannheimia haemolytica serotype 1, Pasteurella multocida and Histophilus somni. This is the first study to demonstrate the vapour phase antimicrobial activity of EOs against BRPs.

The effect of pulmonary surfactant on the in vitro activity of Iclaprim against common respiratory bacterial pathogens

The in vitro antimicrobial activity of iclaprim, a novel diaminopyrimidine, against common respiratory bacteria remained unchanged in the presence of pulmonary surfactant (Survanta®) at concentrations that greatly antagonized the antimicrobial activity of daptomycin. These results indicate that iclaprim could be a potential treatment for pneumonia caused by susceptible and multidrug resistant bacteria.

Simultaneous Detection of 13 Key Bacterial Respiratory Pathogens by Combination of Multiplex PCR and Capillary Electrophoresis

ObjectiveLower respiratory tract infections continue to pose a significant threat to human health. It is important to accurately and rapidly detect respiratory bacteria. To compensate for the limits of current respiratory bacteria detection methods, we developed a combination of multiplex polymerase chain reaction (PCR) and capillary electrophoresis (MPCE) assay to detect thirteen bacterial pathogens responsible for lower respiratory tract infections, including Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella spp., Bordetella pertussis, Mycobacterium tuberculosis complex, Corynebacterium diphtheriae, and Streptococcus pyogenes. MethodsThree multiplex PCR reactions were built, and the products were analyzed by capillary electrophoresis using the high-throughput DNA analyzer. The specificity of the MPCE assay was examined and the detection limit was evaluated using DNA samples from each bacterial strain and the simulative samples of each strain. This assay was further evaluated using 152 clinical specimens and compared with real-time PCR reactions. For this assay, three nested-multiplex-PCRs were used to detect these clinical specimens. ResultsThe detection limits of the MPCE assay for the 13 pathogens were very low and ranged from 10−7 to 10−2 ng/μL. Furthermore, analysis of the 152 clinical specimens yielded a specificity ranging from 96.5%-100.0%, and a sensitivity of 100.0% for the 13 pathogens. ConclusionThis study revealed that the MPCE assay is a rapid, reliable, and high-throughput method with high specificity and sensitivity. This assay has great potential in the molecular epidemiological survey of respiratory pathogens.

A Genoproteomic Approach to Detect Peptide Markers of Bacterial Respiratory Pathogens.

Rapid identification of respiratory pathogens may facilitate targeted antimicrobial therapy. Direct identification of bacteria in bronchoalveolar lavage (BAL) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry is confounded by interfering substances. We describe a method to identify unique peptide markers of 5 gram-negative bacteria by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for direct pathogen identification in BAL. In silico translation and digestion were performed on 14-25 whole genomes representing strains of Acinetobacter baumannii, Moraxella catarrhalis, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Klebsiella pneumoniae. Peptides constituting theoretical core peptidomes in each were identified. Rapid tryptic digestion was performed; peptides were analyzed by LC-MS/MS and compared with the theoretical core peptidomes. High-confidence core peptides (false discovery rate <1%) were identified and analyzed with the lowest common ancestor search to yield potential species-specific peptide markers. The species specificity of each peptide was verified with protein BLAST. Further, 1 or 2 pathogens were serially diluted into pooled inflamed BAL, and a targeted LC-MS/MS assay was used to detect 25 peptides simultaneously. Five unique peptides with the highest abundance for each pathogen distinguished these pathogens with varied detection sensitivities. Peptide markers for A. baumannii and P. aeruginosa, when spiked simultaneously into inflamed BAL, were detected with as few as 3.6 (0.2) × 103 and 2.2 (0.6) × 103 colony-forming units, respectively, by targeted LC-MS/MS. This proof-of-concept study shows the feasibility of identifying unique peptides in BAL for 5 gram-negative bacterial pathogens, and it may provide a novel approach for rapid direct identification of bacterial pathogens in BAL.

Prevalence and antimicrobial susceptibility of Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni isolated from the lower respiratory tract of healthy feedlot cattle and those diagnosed with bovine respiratory disease

Current information on prevalence and antimicrobial resistance (AMR) of bacterial respiratory pathogens is crucial to guide antimicrobial choice for control and treatment of bovine respiratory disease (BRD). The objectives were to describe the prevalence of three BRD-associated bacteria (Mannheimia haemolytica, Pasteurella multocida, and Histophilus somni) in the lower airways of feedlot cattle, and to analyze AMR in these bacteria. Cattle with (n=210) and without (n=107) BRD were sampled by trans-tracheal aspiration at four feedlots (Nov. 15–Jan. 16). These cattle had received 2.5mg/kg of tulathromycin on arrival at the feedlot for BRD control and two in-feed pulses of chlortetracycline (5g/animal/day for 5days) within the first 21days on feed to prevent histophilosis. Bacteria were detected by culture and AMR was tested by microdilution. Pasteurella multocida was the most frequent bacterium isolated in cattle with BRD (54.8%), followed by M. haemolytica (30.5%) and H. somni (22.9%). Compared to those with BRD, healthy cattle were less likely to be positive for P. multocida (OR=0.27), M. haemolytica (OR=0.32), or H. somni (OR=0.25). There were high levels of resistance (>70%) against tulathromycin and oxytetracycline in M. haemolytica and P. multocida isolates and high levels of resistance against oxytetracycline (67%) and penicillin (52%) in H. somni isolates. None or few isolates were resistant to florfenicol, enrofloxacin and ceftiofur. The high prevalence of resistance against tulathromycin and oxytetracycline suggests that these antimicrobials should not be repeatedly used for both control and treatment of BRD and/or histophilosis.

IL-33: a jack of all trades in the orchestration of respiratory antibacterial immunity.

Influenza A virus (IAV) is the causative agent of mostly mild to moderate seasonal respiratory infections and several pandemic outbreaks, the most recent of which was reported in 2009. Previous IAV pandemics were associated with an enormous death toll; for example, the 1918 H1N1 pandemic affected hundreds of millions of people globally and resulted in ~50 million deaths.1 Microbiologic analyses of patient samples revealed a strong incidence of bacterial pathogens in fatal complications of viral infection.2 To date, many pieces of epidemiologic and experimental evidence reveal pronounced susceptibility to detrimental bacterial superinfection in IAV-infected individuals. The physiologic mechanisms underlying the fatal synergism between IAV and opportunistic respiratory bacterial pathogens are so far incompletely understood. Among these mechanisms, the depletion3 or dysfunction4 of professional phagocytes, attenuation of antimicrobial production5 or desensitization to microbial-associated molecular patterns (MAMPs)6 are just a few examples indicating the deactivation of airway antimicrobial defense during IAV infection.

Nationwide surveillance of bacterial respiratory pathogens conducted by the surveillance committee of Japanese Society of Chemotherapy, the Japanese Association for Infectious Diseases, and the Japanese Society for Clinical Microbiology in 2012: General view of the pathogens' antibacterial susceptibility.

The nationwide surveillance on antimicrobial susceptibility of bacterial respiratory pathogens from the patients in Japan was conducted by Japanese Society of Chemotherapy, Japanese association for infectious diseases and Japanese society for Clinical Microbiology in 2012. The isolates were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections during the period between January and December in 2012 by three societies. Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Clinical Laboratory Standard Institutes. Susceptibility testing was evaluated in 1236 strains (232 Staphylococcus aureus, 225 Streptococcus pneumoniae, 16 Streptococcus pyogenes, 231 Haemophilus influenzae, 147 Moraxella catarrhalis, 167 Klebsiella pneumoniae and 218 Pseudomonas aeruginosa). Ratio of methicillin-resistant S.aureus was 51.3%, and those of penicillin-intermediate S.pneumoniae was 0.4%. Among H.influenzae, 5.6% of them were found to be β-lactamase-producing ampicillin-resistant strains, and 37.2% to be β-lactamase-non-producing ampicillin-resistant strains. Extended spectrum β-lactamase-producing K.pneumoniae and multi-drug resistant P.aeruginosa with metallo β-lactamase were 4.2% and 3.2%, respectively. Continuous national surveillance is important to determine the actual situation of the resistance shown by bacterial respiratory pathogens to antimicrobial agents.

Surveillance of upper respiratory infections using a new multiplex PCR assay compared to conventional methods during the influenza season in Taiwan

ObjectivesTo improve diagnosis as part of laboratory surveillance in Taiwan, influenza-like illness (ILI) surveillance was conducted using a new multiplex PCR assay (FilmArray) and the results compared to those of conventional methods The study was performed during the winter months. MethodsThroat swabs from patients with an ILI presenting to physicians in sentinel practices were collected during the 2016–2017 influenza season. ResultsA total of 52 samples tested positive by FilmArray Respiratory Panel. Forty percent were influenza A virus, and subtype H3N2 virus was the major epidemic strain. However, nearly 60% of ILI cases seen at sentinel sites were caused by non-influenza pathogens. The results of the FilmArray assay and cell culture were identical, and this assay was more sensitive than a rapid influenza diagnostic test. Genetic analyses revealed new influenza A H3N2 variants belonging to a novel subclade 3C.2a2. ConclusionsThe FilmArray assay facilitates urgent testing and laboratory surveillance for common viral and bacterial respiratory pathogens. This study demonstrated the use of a highly sensitive assay using clinical samples that is feasible for application worldwide. This may lead to an increased rate of diagnosis of viral infections and to improved patient outcomes, and in particular to a reduction in the overuse of antibiotics and antivirals.