Insights into the genetic contexts of sulfonamide resistance among early clinical isolates of Acinetobacter baumannii

Acinetobacter baumannii: A comprehensive review of global epidemiology, clinical implications, host interactions, mechanisms of antimicrobial resistance and mitigation strategies

Since the discovery of Acinetobacter baumannii, it has emerged as a significant global health threat due to its increasing prevalence in healthcare settings and remarkable ability to develop resistance to various antibiotics. This detailed review addresses global epidemiology, emphasizing the worldwide distribution of carbapenem-resistant A. baumannii (CRAb), which is particularly prevalent in high-density healthcare settings and regions with intensive antibiotic usage, such as India. Clinically, A. baumannii infection poses serious health challenges, with mortality rates ranging from 30 % to 75 % for multidrug-resistant (MDR) strains. The review highlights the clinical impact and disease spectrum of A. baumannii, associated with pneumonia, wound infections, bloodstream infections, and, urinary tract infections with a strong association to invasive medical procedures and devices. Additionally, it discusses human-pathogen interactions by exploring various mechanisms, persistence in hospital environments, and survival under harsh conditions. The review further elaborates on different resistance mechanisms, focusing broadly on antibiotic degradation, altered drug targets, reduced drug permeability, and efflux systems, which facilitate the survival and persistence of A. baumannii. Finally, it evaluates strategies to combat AMR, emphasizing infection control measures, antimicrobial stewardship, and the urgent need for innovative therapeutic approaches such as phage therapy and new antibiotic development. The review calls for concerted, collaborative efforts among researchers, healthcare professionals, and public health authorities to mitigate the global threat posed by MDR A. baumannii strains.

Screening and identification of multiple antibiotic- resistant genes containing Salmonella Typhi from drinking water: A severe public health concern in Bangladesh

Contaminated water poses a significant public health risk due to waterborne microbial diseases, with typhoid caused by Salmonella Typhi being the most prevalent bacterial waterborne disease in Bangladesh. This study aimed to assess the presence of antibiotic-resistant genes and their patterns in Salmonella Typhi isolated from drinking water sources in Chattogram City, Bangladesh. Out of 150 samples analyzed, 10 isolates were suspected to be Salmonella Typhi by selective plating and biochemical test and 8 were confirmed using PCR amplification of the fliC gene and subsequent sequencing. Phylogenetic analysis provided insights into the genetic diversity and relationships among the identified isolates. The study revealed the presence of Salmonella Typhi in certain drinking water sources, indicating a potential threat to public health. The presence of antibiotic-resistant genes, including sul2, int1, tem, and gyrA, in the genomic and plasmid DNA of Salmonella Typhi isolates emphasizes the role of contaminated water in spreading antibiotic resistance. All 8 isolates were found to contain at least one antibiotic-resistant gene highlighting the widespread presence of resistance elements. This raises serious concerns about the potential impact on the effectiveness of typhoid treatment. Antibiotic susceptibility testing using the disk diffusion assay confirmed multidrug resistance (MDR) in 87.5 % of the Salmonella Typhi isolates, highlighting the urgent need to address the transmission of antibiotic-resistant genes through drinking water sources. The results confirm the widespread environmental transmission of antibiotic resistance in the region and emphasize the potential consequences for the efficacy of typhoid treatment.

Genomic Characterization of Mobile Genetic Elements Associated with Multidrug-Resistant Acinetobacter Non-baumannii Species from Southern Thailand

This study investigated the genetic diversity, antimicrobial resistance profiles, and virulence characteristics of Acinetobacter non-baumannii isolates obtained from four hospitals in southern Thailand. Clinical data, genome information, and average nucleotide identity (ANI) were analyzed for eight isolates, revealing diverse genetic profiles and novel sequence types (STs). Minimum spanning tree analysis indicated potential clonal spread of certain STs across different geographic regions. Antimicrobial resistance genes (ARGs) were detected in all isolates, with a high prevalence of genes conferring resistance to carbapenems, highlighting the challenge of antimicrobial resistance in Acinetobacter spp. infections. Mobile genetic elements (MGEs) carrying ARGs were also identified, emphasizing the role of horizontal gene transfer in spreading resistance. Evaluation of virulence-associated genes revealed a diverse range of virulence factors, including those related to biofilm formation and antibiotic resistance. However, no direct correlation was found between virulence-associated genes in Acinetobacter spp. and specific clinical outcomes, such as infection severity or patient mortality. This complexity suggests that factors beyond gene presence may influence disease progression and outcomes. This study emphasizes the importance of continued surveillance and molecular epidemiological studies to combat the spread of multidrug-resistant (MDR) Acinetobacter non-baumannii strains. The findings provide valuable insights into the epidemiology and genetic characteristics of this bacteria in southern Thailand, with implications for infection control and antimicrobial management efforts.