Comprehensive Assessment of Inactivation Methods for Madariaga Virus.

The Eastern Equine Encephalitis Virus (EEEV) is an emerging public health threat, with the number of reported cases in the US increasing in recent years. EEEV is a BSL3 pathogen, and the North American strain is a US Federal Select Agent (SA). These restrictions make experiments with EEEV difficult to perform, as high-tech equipment is often unavailable in BSL3 spaces and due to concerns about generating aerosols during manipulations. Therefore, a range of inactivation methods suitable for different downstream analysis methods are essential for advancing research on EEEV. We used heat, chemical, and ultraviolet (UV)-based methods for the inactivation of infected cells and supernatants infected with the non-select agent Madariaga virus (MADV). Although the MADV and EEEV strains are genetically distinct, differing by 8-11% at the amino acid level, they are expected to be similarly susceptible to various inactivation methods. We determined the following to be effective methods of inactivation: heat, TRIzol LS, 4% PFA, 10% formalin, and UV radiation for infected supernatants; TRIzol, 2.5% SDS with BME, 0.2% NP40, 4% PFA, and 10% formalin for infected cells. Our results have the potential to expand the types and complexity of experiments and analyses performed by EEEV researchers.

Secondary plant metabolites as potent drug candidates against antimicrobial-resistant pathogens.

Antibiotic resistance is a major public health threat of the twenty-first century and represents an important risk to the global economy. Healthcare-associated infections mainly caused by drug-resistant bacteria are wreaking havoc in patient care worldwide. The spread of such pathogens limits the utility of available drugs and complicates the treatment of bacterial diseases. As a result, there is an urgent need for new drugs with mechanisms of action capable of curbing resistance. Plants synthesize and utilize various metabolic compounds to deter pathogens and predators. Utilizing these plant-based metabolites is a promising option in identifying novel bioactive compounds that could be harnessed to develop new potent antimicrobial drugs to treat multidrug-resistant pathogens. The purpose of this review is to highlight medicinal plants as important sources of novel antimicrobial agents that could be developed to help combat antimicrobial resistance.

Emergence of Clinical Clostridioides difficile Isolates With Decreased Susceptibility to Vancomycin.

BACKGROUND: Clostridioides difficile infection (CDI) is a leading cause of hospital-associated antibiotic-related diarrhea and deaths worldwide. Vancomycin is one of the few antibiotics recommended for both nonsevere and severe CDI cases. We sought to determine whether vancomycin nonsusceptible C. difficile strains are circulating in the patient population. METHODS: Stool samples from patients with CDI were collected from 438 and 98 patients at a large university hospital in Houston, Texas, and Nairobi, Kenya, respectively. The stools were examined for the presence of vancomycin and metronidazole nonsusceptible C. difficile using broth dilution culture, Etest (BioMérieux, France), polymerase chain reaction (PCR), whole-genome sequencing, and in vivo testing in a CDI mouse model. RESULTS: Of the Houston stool samples, 114/438 (26%) had vancomycin nonsusceptible C. difficile isolates and 128/438 (29%) were metronidazole nonsusceptible. Similarly, 66 out of 98 (67%) and 83/98 (85%) of the Nairobi patients harbored vancomycin and metronidazole nonsusceptible isolates, respectively. Vancomycin treatment of a CDI mouse model infected with a vancomycin nonsusceptible isolate failed to eradicate the infection. Whole-genome sequencing analyses did not identify vanA genes, suggesting a different mechanism of resistance. CONCLUSIONS: C. difficile strains exhibiting reduced susceptibility to vancomycin are currently circulating in patient populations. The spread of strains resistance to vancomycin, a first-line antibiotic for CDI, poses a serious therapeutic challenge. Routine susceptibility testing may be necessary.

Pesticides Decrease Bacterial Diversity and Abundance of Irrigated Rice Fields.

Bacteria play an important role in soil ecosystems and their activities are crucial in nutrient composition and recycling. Pesticides are extensively used in agriculture to control pests and improve yield. However, increased use of pesticides on agricultural lands results in soil contamination, which could have adverse effect on its bacterial communities. Here, we investigated the effect of pesticides commonly used on irrigated rice fields on bacterial abundance and diversity. Irrigated soil samples collected from unexposed, pesticide-exposed, and residual exposure areas were cultured under aerobic and anaerobic conditions. DNA was extracted and analysed by 16S rRNA sequencing. The results showed overall decrease in bacterial abundance and diversity in areas exposed to pesticides. Operational taxonomic units of the genera Enterobacter, Aeromonas, Comamonas, Stenotrophomonas, Bordetella, and Staphylococcus decreased in areas exposed to pesticides. Conversely, Domibacillus, Acinetobacter, Pseudomonas, and Bacillus increased in abundance in pesticide-exposed areas. Simpson and Shannon diversity indices and canonical correspondence analysis demonstrated a decrease in bacterial diversity and composition in areas exposed to pesticides. These results suggest bacteria genera unaffected by pesticides that could be further evaluated to identify species for bioremediation. Moreover, there is a need for alternative ways of improving agricultural productivity and to educate farmers to adopt innovative integrated pest management strategies to reduce deleterious impacts of pesticides on soil ecosystems.