Publications by authors named "William Nierman"

Background: Lower respiratory tract infection (LRTI) is a leading cause of infant morbidity and mortality globally. LRTI may be caused by viral or bacterial infections, individually or in combination. We investigated associations between LRTI and infant nasopharyngeal (NP) viruses and bacteria in a South African birth cohort.

View Article and Find Full Text PDF

Background: Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa.

View Article and Find Full Text PDF

To better combat the expansion of antibiotic resistance in pathogens, new compounds, particularly those with novel mechanisms-of-action [MOA], represent a major research priority in biomedical science. However, rediscovery of known antibiotics demonstrates a need for approaches that accurately identify potential novelty with higher throughput and reduced labor. Here we describe an explainable artificial intelligence classification methodology that emphasizes prediction performance and human interpretability by using a Hierarchical Ensemble of Classifiers model optimized with a novel feature selection algorithm called Clairvoyance; collectively referred to as a CoHEC model.

View Article and Find Full Text PDF

Mucormycoses are invasive infections by species and other Mucorales. Over 10 months, four solid organ transplant (SOT) recipients at our centre developed mucormycosis due to (=2), (=1) or (=1), at a median 31.5 days (range: 13-34) post-admission.

View Article and Find Full Text PDF
Article Synopsis
  • * A study tracked pneumococcal carriage in 137 PCV-13 vaccinated infants by collecting nasopharyngeal samples bi-weekly during their first year, examining changes in serotypes and antibiotic resistance.
  • * Out of 196 sequenced samples, 174 showed positive pneumococcal cultures with diverse serotypes identified; high rates of antibiotic-resistant mutations were present, especially linked to cotrimoxazole resistance.
View Article and Find Full Text PDF
Article Synopsis
  • Nasopharyngeal colonization with antimicrobial-resistant bacteria poses a significant global health threat, as these bacteria can transfer resistance genes to harmful pathogens, yet little is understood about the NP antimicrobial resistome.
  • In a study involving 196 NP samples from 23 infants in South Africa, researchers used whole metagenome shotgun sequencing to analyze the antibiotic resistome, identifying 329 AMR genes, with 64% of samples showing resistance genes.
  • The results indicated a diverse range of AMR genes, predominantly related to beta-lactam antibiotics, and highlighted the potential of WMGS to comprehensively assess the NP resistome over time.
View Article and Find Full Text PDF
Article Synopsis
  • The study investigates Burkholderia cepacia and Burkholderia contaminans, pathogens found in the potable water dispenser of the International Space Station, by sequencing their genomes and conducting various tests.
  • The isolates from the ISS show over 99% genetic similarity and likely originated from just two main populations, indicating a closely related lineage.
  • While these pathogens retain their virulence, they don't appear to be more harmful than similar strains on Earth, and they remain susceptible to antibiotics commonly used in clinical settings.
View Article and Find Full Text PDF

The annotated genome of , a recently discovered drug-resistant pathogen, was determined by employing the Oxford Nanopore MinION platform and the Funannotate pipeline. The genome size and the number of protein-coding genes are notably larger than those of the most common etiological agent of aspergillosis, .

View Article and Find Full Text PDF

Antimicrobial resistance (AMR) is an ever-growing public health problem worldwide. The low rate of antibiotic discovery coupled with the rapid spread of drug-resistant bacterial pathogens is causing a global health crisis. To facilitate the drug discovery processes, we present a large-scale study of reference antibiotic challenge bacterial transcriptome profiles, which included 37 antibiotics across 6 mechanisms of actions (MOAs) and provide an economical approach to aid in antimicrobial dereplication in the discovery process.

View Article and Find Full Text PDF

Aspergillus flavus is a saprophytic fungus that infects corn, peanuts, tree nuts and other agriculturally important crops. Once the crop is infected the fungus has the potential to secrete one or more mycotoxins, the most carcinogenic of which is aflatoxin. Aflatoxin contaminated crops are deemed unfit for human or animal consumption, which results in both food and economic losses.

View Article and Find Full Text PDF

There are limited data on meconium and faecal bacterial profiles from African infants and their mothers. We characterized faecal bacterial communities of infants and mothers participating in a South African birth cohort. Stool and meconium specimens were collected from 90 mothers and 107 infants at birth, and from a subset of 72 and 36 infants at 4-12 and 20-28 weeks of age, respectively.

View Article and Find Full Text PDF

Pneumococcal pneumonia has decreased significantly since the implementation of the pneumococcal conjugate vaccine (PCV), nevertheless, in many developing countries pneumonia mortality in infants remains high. We have undertaken a study of the nasopharyngeal (NP) microbiome during the first year of life in infants from The Philippines and South Africa. The study entailed the determination of the sp.

View Article and Find Full Text PDF

Functional coupling of calcium- and alkaline responsive signalling occurs in multiple fungi to afford efficient cation homeostasis. Host microenvironments exert alkaline stress and potentially toxic concentrations of Ca , such that highly conserved regulators of both calcium- (Crz) and pH- (PacC/Rim101) responsive signalling are crucial for fungal pathogenicity. Drugs targeting calcineurin are potent antifungal agents but also perturb human immunity thereby negating their use as anti-infectives, abrogation of alkaline signalling has, therefore, been postulated as an adjunctive antifungal strategy.

View Article and Find Full Text PDF

Aspergillus fumigatus is a versatile fungus able to successfully exploit diverse environments from mammalian lungs to agricultural waste products. Among its many fitness attributes are dozens of genetic loci containing biosynthetic gene clusters (BGCs) producing bioactive small molecules (often referred to as secondary metabolites or natural products) that provide growth advantages to the fungus dependent on environment. Here we summarize the current knowledge of these BGCs-18 of which can be named to product-their expression profiles in vivo, and which BGCs may enhance virulence of this opportunistic human pathogen.

View Article and Find Full Text PDF

Most antibiotics were discovered by screening soil actinomycetes, but the efficiency of the discovery platform collapsed in the 1960s. By now, more than 3000 antibiotics have been described and most of the current discovery effort is focused on the rediscovery of known compounds, making the approach impractical. The last marketed broad-spectrum antibiotics discovered were daptomycin, linezolid, and fidaxomicin.

View Article and Find Full Text PDF

We used ribonucleic acid sequencing to profile transcription within biliary fluid from a patient with cholangitis; samples were collected before and after treatment with fluconazole and drainage. transcriptomes at the infection site distinguished treated from untreated cholangitis. After treatment, 1131 genes were differentially expressed in biliary fluid.

View Article and Find Full Text PDF

Fungi of the genus Aspergillus are widespread in the environment. Some Aspergillus species, most commonly Aspergillus fumigatus, may lead to a variety of allergic reactions and life-threatening systemic infections in humans. Invasive aspergillosis occurs primarily in patients with severe immunodeficiency, and has dramatically increased in recent years.

View Article and Find Full Text PDF

Bacterial persistence due to antibiotic tolerance is a critical aspect of antibiotic treatment failure, disease latency, and chronic or reemergent infections. The levels of persisters is especially notable for the opportunistic Gram-negative pathogens from the Burkholderia and Pseudomonas genera. We examined the rate of drug tolerant persisters in Burkholderia pseudomallei, Burkholderia thailandensis, Burkholderia cepacia complex organisms, and Pseudomonas aeruginosa at mid-log growth in LB broth culture.

View Article and Find Full Text PDF

Invasive aspergillosis (IA) due to Aspergillus fumigatus is a major cause of mortality in immunocompromised patients. The discovery of highly fertile strains of A. fumigatus opened the possibility to merge classical and contemporary genetics to address key questions about this pathogen.

View Article and Find Full Text PDF

Aflatoxin contamination of food and livestock feed results in significant annual crop losses internationally. Aspergillus flavus is the major fungus responsible for this loss. Additionally, A.

View Article and Find Full Text PDF

Penicillium marneffei can cause a fatal systemic mycosis in patients infected with the HIV. Infections are endemic in the tropical regions of southeast Asia. Here, we report the genome sequences of the type strains of P.

View Article and Find Full Text PDF

Receipt of broad-spectrum antibiotics enhances Candida albicans colonization of the GI tract, a risk factor for haematogenously-disseminated candidiasis. To understand how antibiotics influence C. albicans colonization, we treated mice orally with vancomycin or a combination of penicillin, streptomycin, and gentamicin (PSG) and then inoculated them with C.

View Article and Find Full Text PDF

Background: Microbiome studies incorporate next-generation sequencing to obtain profiles of microbial communities. Data generated from these experiments are high-dimensional with a rich correlation structure but modest sample sizes. A statistical model that utilizes these microbiome profiles to explain a clinical or biological endpoint needs to tackle high-dimensionality resulting from the very large space of variable configurations.

View Article and Find Full Text PDF

Iron plays a critical role in survival and virulence of the opportunistic pathogen Aspergillus fumigatus. Two transcription factors, the GATA-factor SreA and the bZip-factor HapX oppositely monitor iron homeostasis with HapX activating iron acquisition pathways (e.g.

View Article and Find Full Text PDF