Centre for Infectious Diseases and Microbiology Laboratory Services, Institute of Clinical Pathology and Medical Research, Westmead Hospital, 3rd Level, ICPMR Building, Westmead, NSW, 2145, Australia.
Molecular Mycology Research Laboratory, Center for Infectious Diseases and Microbiology, Sydney Medical School-Westmead Hospital, University of Sydney, Westmead, NSW, Australia.
Mycopathologia. 2018 Feb;183(1):251-261. doi: 10.1007/s11046-017-0140-x. Epub 2017 May 16.
In vitro bacterial-fungal interaction studies in cystic fibrosis (CF) have mainly focused on interactions between bacteria and Candida. Here we investigated the effect of Pseudomonas aeruginosa on the growth of Scedosporium/Lomentospora spp. Standard suspensions of P. aeruginosa (16 non-mucoid and nine mucoid isolates) were dropped onto paper disks, placed on lawns of Lomentospora prolificans (formerly Scedosporium prolificans) strain WM 14.140 or Scedosporium aurantiacum strain WM 11.78 on solid agar. The median inhibitory activity (mIz) was calculated for each fungal-bacterial combination. As a group, mIz values for non-mucoid phenotype P. aeruginosa strains were significantly lower than those for mucoid strains (P < 0.001); 14/16 (87.5%) non-mucoid strains had mIz <1.0 against both fungi versus just 3/9 mucoid strains (33.4%) (P = 0.01). One non-mucoid (PA14) and one mucoid (CIDMLS-PA-28) P. aeruginosa strain effecting inhibition were selected for further studies. Inhibition of both L. prolificans and S. aurantiacum by these strains was confirmed using the XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide) reduction assay. Following incubation with XTT, inhibition of fungal growth was determined as the ratio of absorbance in liquid culture with Pseudomonas to that in control fungal cultures. An absorbance ratio of <1.0 consistent with bacterial inhibition of fungal growth was observed for all four P. aeruginosa-fungal combinations (P < 0.05). Fluorescence microscopy, subsequent to co-culture of either fungal isolate with P. aeruginosa strain PA14 or CIDMLS-PA-28 revealed poorly formed hyphae, compared with control fungal cultures. P. aeruginosa inhibits growth of L. prolificans and S. aurantiacum in vitro, with non-mucoid strains more commonly having an inhibitory effect. As P. aeruginosa undergoes phenotype transitions from non-mucoid to the mucoid form with progression of CF lung disease, this balance may influence the appearance of Scedosporium fungi in the airways.
在囊性纤维化 (CF) 中进行的细菌-真菌相互作用的体外研究主要集中在细菌和念珠菌之间的相互作用上。在这里，我们研究了铜绿假单胞菌对鞘孢菌/枝孢菌生长的影响。将 16 株非粘液型和 9 株粘液型铜绿假单胞菌（PA）标准悬液滴在纸片上，放置在固体琼脂上的繁茂枝孢霉（原枝孢霉）菌株 WM 14.140 或金黄色枝孢霉菌株 WM 11.78 的菌床上。为每种真菌-细菌组合计算中位抑制活性（mIz）。作为一个整体，非粘液型表型铜绿假单胞菌菌株的 mIz 值明显低于粘液型菌株（P < 0.001）；16 株非粘液型菌株中有 14 株（87.5%）对两种真菌的 mIz < 1.0，而粘液型菌株只有 3 株（33.4%）（P = 0.01）。选择一株非粘液型（PA14）和一株粘液型（CIDMLS-PA-28）铜绿假单胞菌菌株进行进一步研究。使用 XTT（2,3-双（2-甲氧基-4-硝基-5-磺苯基）-5-（苯氨基）羰基-2H-四唑氢氧化铵）还原测定法证实了这些菌株对繁茂枝孢霉和金黄色枝孢霉的抑制作用。在与 XTT 孵育后，通过比较细菌培养物与对照真菌培养物的吸光度，确定真菌生长的抑制程度。所有四种铜绿假单胞菌-真菌组合的吸收比值均<1.0，这与细菌抑制真菌生长一致（P < 0.05）。荧光显微镜观察显示，与对照真菌培养物相比，与铜绿假单胞菌菌株 PA14 或 CIDMLS-PA-28 共培养后，真菌分离株的菌丝形成不良。铜绿假单胞菌在体外抑制繁茂枝孢霉和金黄色枝孢霉的生长，非粘液型菌株更常见具有抑制作用。随着铜绿假单胞菌从非粘液型向粘液型表型的表型转变，随着 CF 肺部疾病的进展，这种平衡可能会影响空气通道中枝孢菌的出现。
