Burkholderia pseudomalleiis a Gram-negative bacterium that causes melioidosis, which can be fatal in humans. Melioidosis is prevalent in the tropical regions of Southeast Asia and Northern Australia. Ecological data have shown that this bacterium can survive as a free-living organism in environmental niches, such as soil and water, as well as a parasite living in host organisms, such as ameba, plants, fungi, and animals. This review provides an overview of the survival and adaptation ofB. pseudomalleito stressful conditions induced by hostile environmental factors, such as salinity, oxidation, and iron levels. The adaptation ofB. pseudomalleiin host cells is also reviewed. The adaptive survival mechanisms of this pathogen mainly involve modulation of gene and protein expression, which could cause alterations in the bacteria’s cell membrane, metabolism, and virulence. Understanding the adaptations of this organism to environmental factors provides important insights into the survival and pathogenesis ofB. pseudomallei, which may lead to the development of novel strategies for the control, prevention, and treatment of melioidosis in the future.

Background and Aim: Domestic and wild animals are important reservoirs for antibiotic-resistant bacteria. This study aimed to isolate Escherichia coli from feces of domestic and wild animals at an agricultural land interface area of Salaphra Wildlife Sanctuary, Thailand, and study the phylogenic characteristics and antibiotic resistance in these isolates. Materials and Methods: In this cross-sectional, descriptive study, we randomly collected ground feces from free-ranging wild animals (deer and elephants) and domestic animals (cattle and goats). All fecal samples were inoculated onto MacConkey agar plates, and lactose-fermenting colonies were identified as E. coli. Antibiotic susceptibility of the E. coli isolates was determined using the disc diffusion method. Polymerase chain reaction assays were used to detect antibiotic resistance and virulence genes. Results: We obtained 362 E. coli isolates from the collected fecal samples. The E. coli isolates were categorized into four phylogenetic groups according to the virulence genes (chuA, vjaA, and TspE4C2). Phylogenetic Group D was predominant in the deer (41.67%) and elephants (63.29%), whereas phylogenetic Group B1 was predominant in the cattle (62.31%), and phylogenetic Groups A (36.36%) and B2 (33.33%) were predominant in the goats. Antibiotic susceptibility testing revealed that most antibiotic-resistant E. coli were isolated from domestic goats (96.96%). Among the 362 E. coli isolates, 38 (10.5%) were resistant to at least one antibiotic, 21 (5.8%) were resistant to two antibiotics, and 6 (1.66%) were resistant to three or more antibiotics. Ampicillin (AMP) was the most common antibiotic (48.48%) to which the E. coli were resistant, followed by tetracycline (TET) (45.45%) and trimethoprim-sulfamethoxazole (3.03%). One isolate from an elephant was resistant to five antibiotics: AMP, amoxicillin, sulfisoxazole, TET, and ciprofloxacin. Determination of antibiotic resistance genes confirmed that E. coli isolates carried antibiotic resistance genes associated with phenotypic resistance to antibiotics. Most antibiotic-resistant E. coli belonged to phylogenic Groups A and B1, and most non-resistant E. coli belonged to phylogenic Groups B2 and D. Conclusion: Monitoring E. coli isolates from wild and domestic animals showed that all four phylogenic groups of E. coli have developed antibiotic resistance and are potential sources of multidrug resistance. High levels of antibiotic resistance have been linked to domestic animals. Our results support strengthening surveillance to monitor the emergence and effects of antibiotic-resistant microorganisms in animals.

Central nervous system (CNS) melioidosis caused by Burkholderia pseudomallei is being increasingly reported. Because of the high mortality associated with CNS melioidosis, understanding the underlying mechanism of B. pseudomallei pathogenesis in the CNS needs to be intensively investigated to develop better therapeutic strategies against this deadly disease. The type VI secretion system (T6SS) is a multiprotein machine that uses a spring-like mechanism to inject effectors into target cells to benefit the infection process. In this study, the role of the T6SS accessory protein TagAB-5 in B. pseudomallei pathogenicity was examined using the human microglial cell line HCM3, a unique resident immune cell of the CNS acting as a primary mediator of inflammation. We constructed B. pseudomallei tagAB-5 mutant and complementary strains by the markerless allele replacement method. The effects of tagAB-5 deletion on the pathogenicity of B. pseudomallei were studied by bacterial infection assays of HCM3 cells. Compared with the wild type, the tagAB-5 mutant exhibited defective pathogenic abilities in intracellular replication, multinucleated giant cell formation, and induction of cell damage. Additionally, infection by the tagAB-5 mutant elicited a decreased production of interleukin 8 (IL-8) in HCM3, suggesting that efficient pathogenicity of B. pseudomallei is required for IL-8 production in microglia. However, no significant differences in virulence in the Galleria mellonella model were observed between the tagAB-5 mutant and the wild type. Taken together, this study indicated that microglia might be an important intracellular niche for B. pseudomallei, particularly in CNS infection, and TagAB-5 confers B. pseudomallei pathogenicity in these cells.

Encephalitozoon cuniculi can cause serious disease and subclinical infection in rabbits and requires active surveillance to control the infection. This study investigated the association between anti-Encephalitozoon cuniculi antibody status and various health parameters in pet rabbits. A total of 90 rabbits were divided into healthy (N = 30), subclinical (N = 30), and clinical (N = 30) groups based on their anti-Encephalitozoon cuniculi antibody status and clinical presentations. The mean ages of the control (37 ± 40 months) and subclinical groups (38 ± 34 months) were notably lower compared to that of the clinical group (63 ± 38 months, p < 0.01). Serum titers for anti-Encephalitozoon cuniculi antibodies were significantly elevated in rabbits with subclinical and clinical infections compared to those of healthy rabbits (p < 0.05). Neurological signs were predominant in rabbits with active E. cuniculi infection (80.0%), with additional pathological features including urinary dysfunction (10.0%) and cataracts (10.0%). The source of rabbits was not associated with E. cuniculi infection (p = 0.159). Anemia was significantly linked to E. cuniculi infection (p = 0.026); however, no significant associations were found with leukocytosis, thrombocytopenia, or serum biochemistry parameters. Mature adult rabbits were more likely to be infected with E. cuniculi. Recognizing anemia and neurological signs facilitates in early diagnosis of E. cuniculi infection.

Background: A cataract is one of the underlying causes blindness in animals. Phacoemulsification is the standard procedure in cataract surgery for humans and animals. This procedure has been used to restore vision in cataracts in a variety of animals. However, this technique is difficult in very small animals, such as rodents, due to their small eyes. Case Description: A 4-year-old male domestic chinchilla was presented with cloudiness in the lenses for 1 month. The ophthalmic examination revealed cataracts OU (oculus uterque: both eyes). Positive dazzle reflex OS (oculus sinister; left eye) and negative reflex OD (oculus dexter; right eye) were noted. The electroretinography was low amplitude OS whereas a flat wave form presented OD. In this case, cataract surgery was performed using phacoemulsification without intraocular lenses implantation OS. Postoperative, the chinchilla was alert and could jump on and jump off the ledge in a house. When the veterinarian approached closely to OS, the chinchilla displayed erect body posture and open eyes, whereas the chinchilla was ignored when the veterinarian doing the same OD. The chinchilla was alert and had improved vision observe by this chinchilla can jump on and jump off the ledge in his house throughout the follow-up period 18 months later. Conclusion: In this chinchilla, phacoemulsification was successfully performed and resulted in better overall vision. The chinchilla was alert and could jump on and jump off the ledge in a house after cataract surgery throughout the follow-up period of 18 months.

Encephalitozoon cuniculi causes both clinical and subclinical infections in rabbits, complicating a diagnosis due to the limitations of conventional tools like ELISA. This study analyzes serum proteomic profiles across clinical, subclinical, and healthy rabbits to identify discriminatory biomarkers. Serum from 90 pet rabbits (30 per group) was pooled (10 samples per pool, 3 pools per group) and analyzed using one-dimensional gel electrophoresis and mass spectrometry. The proteomic analysis revealed 109, 98, and 74 proteins expressed in healthy, subclinical, and clinical groups, respectively. Of these, 50, 40, and 33 proteins were unique to the healthy, subclinical, and clinical groups, respectively, with only 10 proteins shared across all. A total of 88 proteins were differentially expressed in infected groups compared to healthy controls. Importantly, 12 proteins were consistently upregulated in both subclinical and clinical infections. These include markers related to the immune response (beta-2-microglobulin, alpha-2-HS-glycoprotein), coagulation (antithrombin-III, alpha-1-antiproteinase S-1), vitamin A transport (retinol-binding proteins), lipid metabolism (apolipoprotein C-III), cytoskeletal regulation (actin-depolymerizing factor), extracellular matrix integrity (fibrillin 2), and oxidative stress (monooxygenase DBH-like 1). Additionally, Gc-globulin and ER lipid-raft-associated 1 were linked to immune modulation and signaling. These findings identify specific serum proteins as promising biomarkers for distinguishing subclinical from clinical encephalitozoonosis in rabbits, enabling an early diagnosis and effective disease monitoring.