More Like this

1. Analysis of virulence phenotypes and antibiotic resistance in clinical strains of Acinetobacter baumannii isolated in Nashville, Tennessee

   https://doi.org/10.1186/s12866-020-02082-1  

   Boone, Ranashia L.; Whitehead, Briana; Avery, Tyra M.; Lu, Jacky; Francis, Jamisha D.; Guevara, Miriam A.; Moore, Rebecca E.; Chambers, Schuyler A.; Doster, Ryan S.; Manning, Shannon D.; et al (December 2021, BMC Microbiology)

   null (Ed.)

   Abstract Background Acinetobacter baumannii is a gram-negative bacterium which causes opportunistic infections in immunocompromised hosts. Genome plasticity has given rise to a wide range of strain variation with respect to antimicrobial resistance profiles and expression of virulence factors which lead to altered phenotypes associated with pathogenesis. The purpose of this study was to analyze clinical strains of A. baumannii for phenotypic variation that might correlate with virulence phenotypes, antimicrobial resistance patterns, or strain isolation source. We hypothesized that individual strain virulence phenotypes might be associated with anatomical site of isolation or alterations in susceptibility to antimicrobial interventions. Methodology A cohort of 17 clinical isolates of A. baumannii isolated from diverse anatomical sites were evaluated to ascertain phenotypic patterns including biofilm formation, hemolysis, motility, and antimicrobial resistance. Antibiotic susceptibility/resistance to ampicillin-sulbactam, amikacin, ceftriaxone, ceftazidime, cefotaxime, ciprofloxacin, cefepime, gentamicin, levofloxacin, meropenem, piperacillin, trimethoprim-sulfamethoxazole, ticarcillin- K clavulanate, tetracyclin, and tobramycin was determined. Results Antibiotic resistance was prevalent in many strains including resistance to ampicillin-sulbactam, amikacin, ceftriaxone, ceftazidime, cefotaxime, ciprofloxacin, cefepime, gentamicin, levofloxacin, meropenem, piperacillin, trimethoprim-sulfamethoxazole, ticarcillin- K clavulanate, tetracyclin, and tobramycin. All strains tested induced hemolysis on agar plate detection assays. Wound-isolated strains of A. baumannii exhibited higher motility than strains isolated from blood, urine or Foley catheter, or sputum/bronchial wash. A. baumannii strains isolated from patient blood samples formed significantly more biofilm than isolates from wounds, sputum or bronchial wash samples. An inverse relationship between motility and biofilm formation was observed in the cohort of 17 clinical isolates of A. baumannii tested in this study. Motility was also inversely correlated with induction of hemolysis. An inverse correlation was observed between hemolysis and resistance to ticarcillin-k clavulanate, meropenem, and piperacillin. An inverse correlation was also observed between motility and resistance to ampicillin-sulbactam, ceftriaxone, ceftoxamine, ceftazidime, ciprofloxacin, or levofloxacin. Conclusions Strain dependent variations in biofilm and motility are associated with anatomical site of isolation. Biofilm and hemolysis production both have an inverse association with motility in the cohort of strains utilized in this study, and motility and hemolysis were inversely correlated with resistance to numerous antibiotics. 

   more » « less
2. Structural and functional characterization of three Type B and C chloramphenicol acetyltransferases from Vibrio species

   https://doi.org/10.1002/pro.3793  

   Alcala, Ashley; Ramirez, Guadalupe; Solis, Allan; Kim, Youngchang; Tan, Kemin; Luna, Oscar; Nguyen, Karen; Vazquez, Daniel; Ward, Michael; Zhou, Min; et al (December 2019, Protein Science)

   Abstract Chloramphenicol acetyltransferases (CATs) were among the first antibiotic resistance enzymes identified and have long been studied as model enzymes for examining plasmid‐mediated antibiotic resistance. These enzymes acetylate the antibiotic chloramphenicol, which renders it incapable of inhibiting bacterial protein synthesis. CATs can be classified into different types: Type A CATs are known to be important for antibiotic resistance to chloramphenicol and fusidic acid. Type B CATs are often called xenobiotic acetyltransferases and adopt a similar structural fold to streptogramin acetyltransferases, which are known to be critical for streptogramin antibiotic resistance. Type C CATs have recently been identified and can also acetylate chloramphenicol, but their roles in antibiotic resistance are largely unknown. Here, we structurally and kinetically characterized threeVibrioCAT proteins from a nonpathogenic species (Aliivibrio fisheri) and two important human pathogens (Vibrio choleraeandVibrio vulnificus). We found all three proteins, including one in a superintegron (V. cholerae), acetylated chloramphenicol, but did not acetylate aminoglycosides or dalfopristin. We also determined the 3D crystal structures of these CATs alone and in complex with crystal violet and taurocholate. These compounds are known inhibitors of Type A CATs, but have not been explored in Type B and Type C CATs. Based on sequence, structure, and kinetic analysis, we concluded that theV. choleraeandV. vulnificusCATs belong to the Type B class and theA. fisheriCAT belongs to the Type C class. Ultimately, our results provide a framework for studying the evolution of antibiotic resistance gene acquisition and chloramphenicol acetylation inVibrioand other species. 

   more » « less
3. Quantification of Climate Footprints of Vibrio vulnificus in Coastal Human Communities of the United States Gulf Coast

   https://doi.org/10.1029/2023GH001005  

   Jamal, Yusuf; Usmani, Moiz; Brumfield, Kyle_D; Singh, Komalpreet; Huq, Anwar; Nguyen, Thanh_Huong; Colwell, Rita; Jutla, Antarpreet (August 2024, GeoHealth)

   Abstract The incidence of vibriosis is rising globally with evidence of climate variability influencing environmental processes that support growth of pathogenicVibrio spp. The waterborne pathogen,Vibrio vulnificuscan invade wounds and has one of the highest case fatality rates in humans. The bacterium cannot be eradicated from the aquatic environment, hence climate driven environmental conditions enhancing growth and dissemination ofV.vulnificusneed to be understood to provide preemptive assessment of its presence and distribution in aquatic systems. To achieve this objective, satellite remote sensing was employed to quantify the association of sea surface temperature (SST) and chlorophyll‐a(chl‐a) in locations with reportedV.vulnificusinfections. Monthly analysis was done in two populated regions of the Gulf of Mexico—Tampa Bay, Florida, and Galveston Bay, Texas. Results indicate warm water, characterized by a 2‐month lag in SST, high concentration of phytoplankton, proxied for zooplankton using 1 month lagged chl‐avalues, was statistically linked to higher odds ofV.vulnificusinfection in the human population. Identification of climate and ecological processes thresholds is concluded to be useful for development of an heuristic prediction system designed to determine risk of infection for coastal populations. 

   more » « less
4. Coupled DNA-labeling and sequencing approach enables the detection of viable-but-non-culturable Vibrio spp. in irrigation water sources in the Chesapeake Bay watershed

   https://doi.org/10.1186/s40793-021-00382-1  

   Malayil, Leena; Chattopadhyay, Suhana; Mongodin, Emmanuel F.; Sapkota, Amy R. (June 2021, Environmental Microbiome)

   Abstract Nontraditional irrigation water sources (e.g., recycled water, brackish water) may harbor human pathogens, includingVibriospp., that could be present in a viable-but-nonculturable (VBNC) state, stymieing current culture-based detection methods. To overcome this challenge, we coupled 5-bromo-2′-deoxyuridine (BrdU) labeling, enrichment techniques, and 16S rRNA sequencing to identify metabolically-activeVibriospp.in nontraditional irrigation water (recycled water, pond water, non-tidal freshwater, and tidal brackish water). Our coupled BrdU-labeling and sequencing approach revealed the presence of metabolically-activeVibriospp. at all sampling sites. Whereas, the culture-based method only detected vibrios at three of the four sites. We observed the presence ofV. cholerae,V. vulnificus, andV. parahaemolyticususing both methods, whileV. aesturianusandV. shiloniiwere detected only through our labeling/sequencing approach. Multiple other pathogens of concern to human health were also identified through our labeling/sequencing approach includingP. shigelloides,B. cereusandE. cloacae. Most importantly, 16S rRNA sequencing of BrdU-labeled samples resulted inVibriospp. detection even when our culture-based methods resulted in negative detection. This suggests that our novel approach can effectively detect metabolically-activeVibriospp. that may have been present in a VBNC state, refining our understanding of the prevalence of vibrios in nontraditional irrigation waters. 

   more » « less
5. Isolation and characterization of four novel Vibrio parahaemolyticus bacteriophages from oysters

   https://doi.org/10.1371/journal.pone.0339894  

   Aldaroub, Joud; Walsky, Chrissy M; Ewell, Rylee E; Aylward, Frank O; Stevens, Ann M; Burke, Alison Kernell (December 2025, PLOS One)

   Fernández_Robledo, José A (Ed.)

   Vibrio parahaemolyticus(VP) is a bacterial pathogen found in brackish and marine water that infects many marine organisms, such as oysters and shrimp. Consumption of raw or undercooked seafood contaminated withV. parahaemolyticusis a primary cause of seafood-borne gastroenteritis in humans. Due to increasing ocean temperatures,V. parahaemolyticuscontamination of oyster beds in the United States has spread up the east and west coasts to the northern-most states. Promising new research is exploring the isolation of bacteriophages againstV. parahaemolyticuswith a long-term goal to possibly decontaminate oyster beds, thereby expanding the harvest season and allowing for safer consumption of seafood. In this study, store-bought oysters harvested from the Chesapeake Bay in Virginia were used to isolate four bacteriophages with activity against a specificV. parahaemolyticusstrain. A standard double agar overlay plaque assay was used to identify phage activity. After phage isolation, the genomes were sequenced, and transmission electron microscopy (TEM) was performed to visualize the virions. The genomes and TEM images revealed four distinct phages. Three of the phages are distinct isolates that exhibit podovirus-like morphology with short tails and genome sizes of approximately 43 kbp. One phage has siphovirus-like morphology and is a mid-sized tailed phage with a genome size of 80 kbp. Although spot tests performed with the oyster homogenates on up to 10 differentV. parahaemolyticusstrains recovered activity across a wide range of hosts, plaque assays with the isolated phages showed limited host range. Future work will be necessary to determine the viability of using the bacteriophages for elimination ofV. parahaemolyticusin harvested oysters, treatment of aquaculture seed and spat, and/or the environment. 

   more » « less