Enhanced expression of NLRP3 inflammasome components by monocytes of patients with pulmonary paracoccidioidomycosis is associated with smoking and intracellular hypoxemia Publication date: Available online 23 November 2019 Source: Microbes and Infection Author(s): Barbara Casella Amorim, Ana Carla Pereira-Latini, Márjorie de Assis Golim, Raul Lopes Ruiz Júnior, Hugo Hyung Bok Yoo, Maria Sueli Parreira de Arruda, Aldo Henrique Tavares, Ricardo Souza Cavalcante, Rinaldo Poncio Mendes, Alessandra Pontillo, James Venturini Abstract Paracoccidioidomycosis (PCM) is a systemic mycosis caused by thermally dimorphic fungi of the genus Paracoccidioides that affects predominantly 30-60-year-old male rural workers. The main clinical forms of the disease are acute/subacute, chronic (CF); almost all CF patients develop pulmonary fibrosis, and they also exhibit emphysema due to smoke. An important cytokine in this context, IL-1β, different from the others, is produced by an intracellular multimolecular complex called inflammasome that is activated by pathogens and/or host signs of damage. Inflammasome has been recognized for its contribution to chronic inflammatory diseases, from that, we hypothesized that this activation could be involved in paracoccidioidomycosis, contributing to chronic inflammation. While inflammasome activation has been demonstrated in experimental models of P. brasiliensis infection, no information is available in patients, leading us to investigate the participation of NLRP3-inflammasome machinery in CF/PCM patients from a Brazilian endemic area. Our findings showed increased priming in mRNA levels of NLRP3 inflammasome genes by monocytes of PCM patients in vitro than healthy controls. Similar intracellular protein expression of NLRP3, CASP-1, ASC, and IL-1β were also observed in freshly isolated monocytes of PCM patients and smoker controls. Increased expression of NLRP3 and ASC was observed in monocytes from PCM patients under hypoxia in comparison with smoker controls. For the first time, we showed that primed monocytes of CF-PCM patients were associated with enhanced expression of components of NLRP3-inflammasome due to smoke. Also, hypoxemia boosted this machinery. These findings reinforce the systemic low-grade inflammation activation observed in PCM during and after treatment.

Metformin promotes Mycobacterium tuberculosis killing and increases the production of human β-defensins in lung epithelial cells and macrophages Publication date: Available online 2 November 2019 Source: Microbes and Infection Author(s): Adrian Rodriguez-Carlos, Claudia Valdez-Miramontes, Paulina Marin-Luevano, Irma González-Curiel, Jose A. Enciso-Moreno, Bruno Rivas-Santiago Abstract Diabetes has been associated with an increased risk of developing tuberculosis. The reasons related to the increased susceptibility to develop TB in type 2 diabetes mellitus (T2DM) individuals, has not been completely elucidated. However, this susceptibility has been attributed to several factors including failures and misfunctioning of the immune system. In the present study, we aimed to determine the role of anti-hyperglycemic drugs such as glyburide, insulin, and metformin to promote the killing of mycobacteria through the regulation of innate immune molecules such as host defense peptides (HDP) in lung epithelial cells and macrophages. Our results showed that metformin reduces bacillary loads in macrophages and lung epithelial cells which correlates with higher production of β-defensin-2, -3 and -4. Since β-defensins are crucial molecules for controlling Mycobacterium tuberculosis growth, the present results suggest that the use of metformin would be the first choice in the treatment for T2DM2, in patients within tuberculosis-endemic areas.

Anti-tuberculosis (TB) chemotherapy dynamically rescues Th1 and CD8+ T effector levels in Han Chinese pulmonary TB patients Publication date: Available online 1 November 2019 Source: Microbes and Infection Author(s): Guobao Li, Fang Yang, Xing He, Zhi Liu, Jiang Pi, Yuzhen Zhu, Xue Ke, Shuyan Liu, Min Ou, Huixin Guo, Zhuoran Zhang, Gucheng Zeng, Guoliang Zhang Abstract CD4+/CD8+ T cells play a major role in conferring immune protection against tuberculosis (TB), but it remains unknown how the immune responses of CD4+/CD8+ T cells exactly correlate with the clinical variables and disease statuses during anti-TB chemotherapy. To address this, several major immune parameters of CD4+/CD8+ T cells in peripheral blood derived from pulmonary TB patients and healthy volunteers were evaluated. We observed that active TB infection induced lower CD3+ T cell and CD4+ T cell levels but higher CD8+T cell levels, while anti-TB chemotherapy reversed these effects. Also, anti-TB treatment induced enhanced production of IL-2 and IFN-γ but reduced expression of IL-10 and IL-6. Moreover, the dynamic changes of CD3, CD4, and CD8 levels did not show a significant association with sputum smear positivity. However, the frequencies of IL-2+CD4+ or IL-10 + CD4+ T effector subpopulation or IL-1β production in peripheral blood showed significant difference between patients positive for sputum smear and patients negative for sputum smear after anti-TB treatment. These findings implicated that recovery of Th1/CD8+T cell effector levels might be critical immunological events in pulmonary TB patients after treatment and further suggested the importance of these immunological parameters as potential biomarkers for prediction of TB progress and prognosis.

T.B. Blues Publication date: Available online 17 October 2019 Source: Microbes and Infection Author(s): Sophia Häfner

Culture-attenuated pathogenic Leptospira lose the ability to survive to complement-mediated-killing due to lower expression of factor H binding proteins Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Azaf Moreno-Torres, Irving R. Malvido-Jiménez, Alejandro de la Peña-Moctezuma, Luz O. Castillo Sánchez, Tatiana R. Fraga, Angela S. Barbosa, Lourdes Isaac, Alfredo Sahagún-Ruiz Abstract Several pathogens including Gram-negative bacteria hijack complement regulators to escape host's innate response. Pathogenic Leptospira species bind Factor H, C4b binding protein and vitronectin from the complement system. We evaluated the ability of low passage (LP) and culture-attenuated (CA) pathogenic strains of Leptospira, to bind Factor H. We used LOCaS46 (Leptospira interrogans sv Canicola), LOVe30 (L. interrogans sv Icterohaemorrhagiae) and MOCA45 (L. santarosai sv Tarassovi), and ten high passage strains of Leptospira [used in the microscopic agglutination test (MAT)]. Afterwards, we assessed their survival in normal human serum (NHS). Interestingly, the ability in binding Factor H was higher for LOCaS46 and LOVe30 LP strains, than for the respective CA strains suggesting that the ability of evading the alternative complement pathway is lost after culture attenuation. Accordingly, the level of mRNA expression of the Factor H binding proteins, LigA, LigB and Lsa23 was higher in these LP strains than in the corresponding CA strains. Unexpectedly, no difference in Factor H binding and surviving was observed between LP and CA MOCA45 strains. The high passage MAT-reference strains showed variation in Factor H binding ability, but, in most cases, the ability for capturing Factor H by Leptospira strains correlated with their survival in NHS.

Studies on formulation of a combination heat killed immunogen from diarrheagenic Escherichia coli and Vibrio cholerae in RITARD model Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Priyadarshini Mukherjee, Vivek Mondal, Ushasi Bhaumik, Ritam Sinha, Sounak Sarkar, Soma Mitra, Debaki Ranjan Howlader, Suhrid Maiti, Asish Kumar Mukhopadhyay, Shanta Dutta, Hemanta Koley Abstract Multiple diarrheagenic enteric bacterial infections cause global morbidity and mortality. A combination vaccine is needed to combat different diarrhea-causing organisms. In our present work, we formulated a combination of antigens from three different diarrheagenic Escherichia coli strains and three different Vibrio cholerae strains. We demonstrated that our newly formulated combination immunogen was able to raise species-specific immunogenicity. This formulation also gave protection against different diarrheagenic E. coli strains in the removable intestinal tie-adult rabbit diarrhea model. However, protective efficacy was not found against the V. cholerae El Tor Ogawa Haitian variant, but challenged with V. cholerae El Tor Inaba or O139 showed protection in rabbits. This is the first report of a single formulated nonliving heat-killed combination immunogen from different diarrheagenic E. coli and V. cholerae that could bestow protection against different bacteria in an animal model.

VraSR has an important role in immune evasion of Staphylococcus aureus with low level vancomycin resistance Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Caihong Gao, Yuanyuan Dai, Wenjiao Chang, Chao Fang, Ziran Wang, Xiaoling Ma Abstract Vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) are increasingly being reported as associated with treatment failure. Previous studies indicated that VISA/hVISA resists clearance by the host immune system, thereby allowing persistence within the host. VraSR is a vancomycin-resistance-associated sensor/regulator that is highly expressed in VISA/hVISA strains. Whether VraSR plays an important role in immune escape by VISA/hVISA strains is unclear. Here, we constructed a vraSR deletion mutant strain (ΔvraSR) and complementary strain (CΔvraSR) in Mu3 to investigate the effect of VraSR on S. aureus viability in polymorphonuclear leukocytes (PMNs). The ΔvraSR strain was more susceptible to phagocytosis by PMNs and reduced the ability of S. aureus to survive within PMNs. ΔvraSR showed phenotypic changes, including a thinner cell wall, reduced adhesion, and decreased biofilm-forming ability. Real-time quantitative PCR revealed that the transcript levels of cell wall synthesis-related genes (cap5K, cap5N, nanA, tagA, murD) and adhesion-associated genes (fnbA, fnbB, clfA, ebps, sbi) were significantly decreased in the ΔvraSR strain compared with Mu3. In summary, VraSR promotes the survival of S. aureus in the host, which may be associated with an increase in the thickness of the cell wall, adhesion, and biofilm formation.

Zika virus infection: an update Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Pauline Ferraris, Hans Yssel, Dorothée Missé Abstract Since the ZIKV outbreak in Brazil in 2015, the scientific community has joined efforts to gather more information on the epidemiology, clinical features and pathogenicity of the virus. Here, we summarize the most important advances made recently and discuss promising, innovative approaches to understand and control ZIKV infection.

ESCMID/ESGMD postgraduate technical workshop on diagnostic microbiology Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Aurélie Scherler, Silvia Ardissone, Jacob Moran-Gilad, Gilbert Greub Abstract The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) workshop on diagnostic microbiology was held in Lausanne from 25th to 28th September 2018. A total of 87 participants from 31 countries participated to this postgraduate technical workshop. Over 4 days, the mornings were dedicated to talks, which covered many subjects including MALDI-TOF, molecular diagnosis, genomics and metagenomics as well as new innovative approaches. The afternoons were dedicated to 12 different practicals covering various aspects of microbiological diagnosis. This ESCMID meeting provided a unique opportunity to exchange knowledge and ideas on the recent tools developed in diagnostic laboratories. This meeting report summarises the key messages of this four-day workshop.

Cholera in the time of likes. Inspirational pathogens and an important pump Publication date: October–November 2019 Source: Microbes and Infection, Volume 21, Issues 8–9 Author(s): Sophia Häfner