Bronchial bacterial colonization in patients with lung cancer

Introduction: Infections are a part of the natural course of lung cancer but few studies have looked at the clinical and microbiological documentation of infections in these patients. The aim of this study is to analyze the profile of potentially pathogenic bacteria that colonize the bronchial tree in patients with primary lung cancer. Material and methods: The study was conducted from January 2006 to August 2007. It included 44 consecutive patients (34 males and 10 females) with primary lung cancer aged from 38 to 77 (mean age of 57.9 years). In all patients, bronchoalveolar lavage (BAL) was performed during bronchofiberoscopy. Obtained BAL fluid was subjected to microbiological examination. The number of bacteria present in 1 ml of fluid was estimated by quantitative culture. A diagnostic level was set on &#8805; 104 cfu/ml. Results: In 26 (59.1%) of 44 patients physiologic bacterial flora was found in the bronchial tree. In three cases (6.8%), potentially pathological bacteria were cultured but their number was < 104 cfu/ml. In 15 (34.1%) cases, the colonization of potentially pathogenic bacteria was &#8805; 104 cfu/ml. Both Gram-positive and Gram-negative bacteria were isolated. The most frequently isolated bacterium in the first group was Streptococcus pneumoniae (n = 7), and in the second group Haemophilus influenzae (n = 3). Multibacterial colonization was found in five patients (11.4%). In four cases (9.1%), the bronchial tree was colonized simultaneously by two and in one case [2.3%] by three types of micro-organism. Multi-drug-resistant strains were not found in the examined materials but among Streptococcus pneumoniae the constitutive MLSB phenotype was observed. Conclusions: 1. Approximately 30% of patients with lung cancer had a respiratory tract colonized by micro-organisms whose number was higher than the assumed diagnostic level. 2. Among micro-organisms colonizing the lower respiratory tract, Gram-positive cocci such as Streptococcus pneumoniae and Staphylococcus aureus were dominant. 3. The analysis of antibiotic-resistance did not detect multi-drug-resistant micro-organisms but some strains of Streptococcus pneumoniae exhibited resistance to macrolide, lincosamide and streptogramin B.Wstęp: Zakażenia stanowią część naturalnego przebiegu raka płuca. Jedynie wyniki nielicznych badań ukazują kliniczną i mikrobiologiczną dokumentację zakażeń u chorych na raka płuca. Celem pracy była ocena profilu szczepów bakteryjnych potencjalnie chorobotwórczych, kolonizujących drzewo oskrzelowe chorych na pierwotnego raka płuca. Materiał i metody: Badanie przeprowadzano od stycznia 2006 roku do sierpnia 2007 roku. Do analizy włączono 44 chorych (34 mężczyzn i 10 kobiet) z pierwotnym rakiem płuca w wieku od 38 do 77 lat (średnia 57,9 roku). U wszystkich chorych, w trakcie bronchofiberoskopii, pobierano popłuczyny oskrzelikowo-pęcherzykowe. Uzyskany materiał poddano badaniu mikrobiologicznemu. Wykonano posiew metodą ilościową, określając liczbę bakterii/ml. Próg diagnostyczny dla posiewu ilościowego przyjęto na poziomie &#8805; 104 cfu/ml. Wyniki: Spośród 44 chorych u 26 (59,1%) stwierdzono obecność fizjologicznej flory bakteryjnej. W trzech przypadkach (6,8%) wykryto szczepy bakterii potencjalnie patogennych w ilości < 104 cfu/ml, a u 15 chorych (34,1%) stwierdzono bakterie potencjalnie patogenne w ilości &#8805; 104 cfu/ml. Wśród izolowanych bakterii stwierdzano zarówno bakterie Gram (+), jak i Gram (-). W pierwszej grupie najczęściej izolowano Streptococcus pneumoniae (n = 7), a w drugiej Haemophilus influenzae (n = 3). Wielobakteryjną kolonizację wykryto u pięciu chorych (11,4%): u czterech chorych (9,1%) stwierdzono jednoczesne występowanie dwóch, a w jednym przypadku (2,3%) - trzech drobnoustrojów. Nie wyhodowano szczepów wieloopornych w badanym materiale. Jednak wśród Streptococcus pneumoniae zaobserwowano występowanie fenotypu z opornością konstytutywną MLSB. Wnioski: 1. U 34,1% badanych chorych na raka płuca stwierdzono kolonizację drzewa oskrzelowego przez drobnoustroje potencjalnie patogenne w liczbie &#8805; 104 cfu/ml. 2. Wśród drobnoustrojów kolonizujących dolne drogi oddechowe chorych na raka płuca dominowały ziarenkowce Gram (+): Streptococcus pneumoniae i Staphylococcus aureus. 3. Analiza wrażliwości nie wykazała obecności drobnoustrojów wieloopornych. Stwierdzono natomiast występowanie szczepów Streptococcus pneumoniae opornych na makrolidy, linkozamidy i streptograminy B

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements