Microbiology
Abstract
ABSTRACTWith the effectiveness of antimicrobials declining as antimicrobial resistance continues to threaten public health, we must look to alternative strategies for the treatment of infections. In this study, we investigated an innovative ‘drug-free’ dual-wavelength irradiation approach that combines two wavelengths of light, 460 nm and 405 nm, against methicillin resistant Staphylococcus aureus (MRSA). MRSA was initially irradiated with 460 nm light (90-360 J/cm2) and subsequently irradiated with aliquots of 405 nm light (54-324 J/cm2). For in vivo studies, mouse skin was abraded and infected with approximately 107 CFU of MRSA and incubated for 3 hours before irradiating with 460 nm (360 J/cm2) and 405 nm (342 J/cm2). Naïve mouse skin was also irradiated to investigate apoptosis. We found that staphyloxanthin, the carotenoid pigment in MRSA cells, promoted resistance to the antimicrobial effects of 405 nm light. In addition, we found that the photolytic effect of 460 nm light on staphyloxanthin attenuated resistance of MRSA to 405 nm light inactivation. Irradiation of 460 nm alone did not elicit any antimicrobial effect on MRSA. In a proof-of-principle mouse skin abrasion infection model, we observed significant inactivation of MRSA by the dual-wavelength irradiation approach. However, when either wavelength of light was administered alone, no significant decrease in bacterial viability was observed. Moreover, exposure of the dual-wavelength irradiation to naïve mouse skin did not result in any visible apoptosis.In conclusion, dual-wavelength irradiation strategy may offer an innovative, effective and safe approach for the treatment of skin infections caused by MRSA.
Authors
Leon G. Leanse, Xueping Sharon Goh, Ji-Xin Cheng, David Hooper, Tianhong Dai
Abstract
Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low-grade inflammation in older adults is commonly associated with increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota. The increasing older population and lack of treatments to reduce aging-related microbiota dysbiosis, leaky gut and inflammation culminates on a rise in aging-related comorbidities, constituting a significant public health concern. Here we demonstrate that a human-origin probiotic cocktail containing 5-Lactobacillus and 5 Enterococcus strains isolated from healthy infant’s gut prevents high-fat diet (HFD)-induced microbiota dysbiosis, leaky gut, inflammation, metabolic dysfunctions and physical function decline in older mice. Probiotic-modulated gut microbiota primarily reduced leaky gut by increasing tight junctions, which in turn reduced inflammation. Mechanistically, probiotics modulated microbiota in a way to increases bile salt hydrolase activity, which in turn increased taurine abundance in the gut that stimulated tight junctions and suppressed gut leakiness. Further, in Caenorhabditis elegans, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function. The results suggest that such probiotic therapies could prevent or treat aging-related leaky gut and inflammation in elderly.
Authors
Shokouh Ahmadi, Shaohua Wang, Ravinder Nagpal, Bo Wang, Shalini Jain, Atefeh Razazan, Sidharth P. Mishra, Xuewei Zhu, Zhan Wang, Kylie Kavanagh, Hariom Yadav
Abstract
Relatively little is known about interactions between the airway microbiome and airway host transcriptome in asthma. Since asthma affects and is affected by the entire airway, studying the upper (e.g., nasal) and lower (e.g., bronchial) airways together represents a powerful approach to understanding asthma. Here, we performed a systematic, integrative study of the nasal and bronchial microbiomes and nasal and bronchial host transcriptomes of children with severe persistent asthma and healthy controls. We found that (a) the microbiomes and host transcriptomes of asthmatic children are each distinct by site (nasal versus bronchial); (b) among asthmatic children, Moraxella and Alloiococcus are hub genera in the nasal microbiome, while there are no hubs among bronchial genera; (c) bronchial Actinomyces is negatively associated with bronchial genes for inflammation, suggesting Actinomyces may be protective; (d) compared with healthy children, asthmatic children express more nasal genes for ciliary function and harbor more nasal Streptococcus; and (e) nasal genera such as Corynebacterium are negatively associated with significantly more nasal genes for inflammation in healthy versus asthmatic children, suggesting a potentially stronger protective role for such nasal genera in healthy versus asthmatic children. Our systematic, integrative study provides a window into host-microbiome associations in asthma.
Authors
Yoojin Chun, Anh Do, Galina Grishina, Alexander Grishin, Gang Fang, Samantha Rose, Chantal Spencer, Alfin Vicencio, Eric Schadt, Supinda Bunyavanich
Abstract
Despite an unprecedented 2 decades of success, the combat against malaria — the mosquito-transmitted disease caused by Plasmodium parasites — is no longer progressing. Efforts toward eradication are threatened by the lack of an effective vaccine and a rise in antiparasite drug resistance. Alternative approaches are urgently needed. Repurposing of available, approved drugs with distinct modes of action are being considered as viable and immediate adjuncts to standard antimicrobial treatment. Such strategies may be well suited to the obligatory and clinically silent first phase of Plasmodium infection, where massive parasite replication occurs within hepatocytes in the liver. Here, we report that the widely used antidiabetic drug, metformin, impairs parasite liver stage development of both rodent-infecting Plasmodium berghei and human-infecting P. falciparum parasites. Prophylactic treatment with metformin curtails parasite intracellular growth in vitro. An additional effect was observed in mice with a decrease in the numbers of infected hepatocytes. Moreover, metformin provided in combination with conventional liver- or blood-acting antimalarial drugs further reduced the total burden of P. berghei infection and substantially lessened disease severity in mice. Together, our findings indicate that repurposing of metformin in a prophylactic regimen could be considered for malaria chemoprevention.
Authors
Iset Medina Vera, Margarida T. Grilo Ruivo, Leonardo F. Lemos Rocha, Sofia Marques, Sangeeta N. Bhatia, Maria M. Mota, Liliana Mancio-Silva
Abstract
BACKGROUND Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridioides difficile infection (rCDI) in adults and children, but donor stool samples are currently screened for only a limited number of potential pathogens. We sought to determine whether putative procarcinogenic bacteria (enterotoxigenic Bacteroides fragilis, Fusobacterium nucleatum, and Escherichia coli harboring the colibactin toxin) could be durably transmitted from donors to patients during FMT.METHODS Stool samples were collected from 11 pediatric rCDI patients and their respective FMT donors prior to FMT as well as from the patients at 2–10 weeks, 10–20 weeks, and 6 months after FMT. Bacterial virulence factors in stool DNA extracts and stool cultures were measured by quantitative PCR: Bacteroides fragilis toxin (bft), Fusobacterium adhesin A (fadA), and Escherichia coli colibactin (clbB).RESULTS Four of 11 patients demonstrated sustained acquisition of a procarcinogenic bacteria. Whole genome sequencing was performed on colony isolates from one of these donor/recipient pairs and demonstrated that clbB+ E. coli strains present in the recipient after FMT were identical to a strain present in the donor, confirming strain transmission. Conversely, 2 patients exhibited clearance of procarcinogenic bacteria following FMT from a negative donor.CONCLUSION Both durable transmission and clearance of procarcinogenic bacteria occurred following FMT, suggesting that additional studies on appropriate screening measures for FMT donors and the long-term consequences and/or benefits of FMT are warranted.FUNDING Crohn’s & Colitis Foundation, the Bloomberg~Kimmel Institute for Cancer Immunotherapy at Johns Hopkins University School of Medicine, the National Cancer Institute, and the Canadian Institutes of Health Research.
Authors
Julia L. Drewes, Alina Corona, Uriel Sanchez, Yunfan Fan, Suchitra K. Hourigan, Melissa Weidner, Sarah D. Sidhu, Patricia J. Simner, Hao Wang, Winston Timp, Maria Oliva-Hemker, Cynthia L. Sears
Abstract
Previous studies have demonstrated the presence of microbial DNA in the fetal environment. However, it remains unclear whether this DNA represents viable bacteria and how it relates to the maternal microbiota across different body sites. We studied the microbiota of human and mouse dyads to understand these relationships, localize bacteria in the fetus, and demonstrate bacterial viability. In human preterm and full-term mother-infant dyads at the time of Cesarean delivery, the oral cavity and meconium of newborn infants born as early as 24 weeks of gestation contained a microbiota that was predicted to originate from in utero sources including the placenta. Using operative deliveries of pregnant mice under highly controlled, sterile conditions in the laboratory, composition, visualization, and viability of bacteria in the in utero compartment and fetal intestine were demonstrated by 16S rRNA gene sequencing, fluorescence in situ hybridization, and bacterial culture. The composition and predicted source of the fetal gut microbiota shifted between mid- and late gestation. Cultivatable bacteria in the fetal intestine were found during mid-gestation but not late gestation. Our results demonstrate a dynamic, viable mammalian fetal microbiota during in utero development.
Authors
Noelle Younge, Jessica R. McCann, Julie Ballard, Catherine Plunkett, Suhail Akhtar, Félix Araújo-Pérez, Amy Murtha, Debra Brandon, Patrick C. Seed
Abstract
Although mucoactive proteins, such as epidermal growth factor (EGF), could improve clinical outcomes of intestinal ulcerative diseases, their gastrointestinal application is limited because of their proteolytic digestion or concerns about tumor promotion. In the present study, ATP-binding cassette (ABC) transporter–linked secretion of human EGF from probiotic Escherichia coli (EGF-EcN) was created to promote beneficial actions of the EGF receptor, which is notably attenuated in patients with intestinal ulcerative injuries. Preventive and postinjury treatment with EGF-EcN alleviated intestinal ulcers and other readouts of disease severity in murine intestinal ulcer models. EGF-EcN administration promoted the restitutive recovery of damaged epithelial layers, particularly via upward expansion of highly proliferating progenitor cells from the lower crypts. Along with the epithelial barrier benefit, EGF-EcN improved goblet cell–associated mucosal integrity, which controls the access of luminal microbiota to the underlying host tissues. Despite concern about the oncogenic action of EGF, EGF-EcN did not aggravate colitis-associated colon cancer; instead, it alleviated protumorigenic activities and improved barrier integrity in the lesions. All findings indicate that probiotic bacteria–based precision delivery of human EGF is a promising mucosal intervention against gastrointestinal ulcers and malignant distress through crypt-derived barrier restoration.
Authors
Mira Yu, Juil Kim, Jung Hoon Ahn, Yuseok Moon
Abstract
Chronic malaria is a major public health problem and significant challenge for disease eradication efforts. Despite its importance, the biological factors underpinning chronic malaria are not fully understood. Recent studies have shown that host metabolic state can influence malaria pathogenesis and transmission, but its role in chronicity is not known. Here, with the goal of identifying distinct modifications in the metabolite profiles of acute versus chronic malaria, metabolomics was performed on plasma from Plasmodium-infected humans and nonhuman primates with a range of parasitemias and clinical signs. In rhesus macaques infected with Plasmodium coatneyi, significant alterations in amines, carnitines, and lipids were detected during a high parasitemic acute phase and many of these reverted to baseline levels once a low parasitemic chronic phase was established. Plasmodium gene expression, studied in parallel in the macaques, revealed transcriptional changes in amine, fatty acid, lipid and energy metabolism genes, as well as variant antigen genes. Furthermore, a common set of amines, carnitines, and lipids distinguished acute from chronic malaria in plasma from human Plasmodium falciparum cases. In summary, distinct host-parasite metabolic environments have been uncovered that characterize acute versus chronic malaria, providing insights into the underlying host-parasite biology of malaria disease progression.
Authors
Regina Joice Cordy, Rapatbhorn Patrapuvich, Loukia N. Lili, Monica Cabrera-Mora, Jung-Ting Chien, Gregory K. Tharp, Manoj Khadka, Esmeralda V.S. Meyer, Stacey A. Lapp, Chester J. Joyner, AnaPatricia Garcia, Sophia Banton, ViLinh Tran, Viravarn Luvira, Siriwan Rungin, Teerawat Saeseu, Nattawan Rachaphaew, Suman B. Pakala, Jeremy D. DeBarry, MaHPIC Consortium, Jessica C. Kissinger, Eric A. Ortlund, Steven E. Bosinger, John W. Barnwell, Dean P. Jones, Karan Uppal, Shuzhao Li, Jetsumon Sattabongkot, Alberto Moreno, Mary R. Galinski
Abstract
Genomic studies revealed the existence of health- and acne-associated P. acnes strains and suggested novel approaches for broadening understanding of acne vulgaris. However, clinical association of P. acnes with disease or health has yet to be corroborated experimentally. Current animal models of acne do not closely mimic human disease and have unclear translational value. We have developed a murine model of acne by combining P. acnes inoculation with topical application of a synthetic human sebum. We showed that human sebum promoted persistence of intradermally injected P. acnes with little loss of viability after 1 week and permitted use of more physiologic inoculums. Application of acne-associated P. acnes RT4/5 strains led to development of moderate to severe skin pathology compared with application of health-associated type II P. acnes strains (RT2/6). RT4/5 P. acnes strains uniformly induced higher levels of KC (IL-8), IL-1α, IL-1β, and IL-6 in vitro and in vivo compared with type II P. acnes strains. Overall, our data provide immunopathologic corroboration of health and disease association of clinical P. acnes strains and inform on a platform to query putative virulence factors uncovered by genomic studies.
Authors
Stacey L. Kolar, Chih-Ming Tsai, Juan Torres, Xuemo Fan, Huiying Li, George Y. Liu
Abstract
Fusobacterium nucleatum is an oral anaerobe prevalent in intrauterine infection associated with a wide spectrum of adverse pregnancy outcomes. We demonstrate here that F. nucleatum triggers placental inflammation through maternal, rather than paternal, TLR4-mediated signaling. Elimination of TLR4 from maternal endothelial cells alleviated placental inflammation and reduced fetal and neonatal death, while elimination of TLR4 in the hematopoietic cells had no effect. The placental inflammatory response followed a spatiotemporal pattern, with NF-κB activation observed first in the maternal endothelial cells and then in the decidual cells surrounding the endothelium, followed by induction of inflammatory cytokines and chemokines. Supplementation of pregnant mice with fish oil as a source of omega-3 fatty acids suppressed placental inflammation, reduced F. nucleatum proliferation in the placenta, and increased fetal and neonatal survival. In vitro analysis illustrates that omega-3 fatty acids inhibit bacterial-induced inflammatory responses from human umbilical cord endothelial cells. Our study therefore reveals a mechanism by which microbial infections affect pregnancy and identifies a prophylactic therapy to protect against intrauterine infections.
Authors
Jeewon Garcia-So, Xinwen Zhang, Xiaohua Yang, Mara Roxana Rubinstein, De Yu Mao, Jan Kitajewski, Kang Liu, Yiping W. Han
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