Plasmid profiling of multiple antibiotic-resistant Pseudomonas aeruginosa isolated from soil of the industrial area in Chittagong, Bangladesh

Agricultural Soil as a Reservoir of Pseudomonas aeruginosa with Potential Risk to Public Health

Pseudomonas aeruginosa is an opportunistic pathogen with a high capacity to adapt to different factors. The aim of this study is to analyze the pathogenicity in P. aeruginosa strains and their resistance to heavy metals and antibiotics, in agricultural soil of the state of Tamaulipas, Mexico. Susceptibility to 16 antibiotics was tested using the Kirby-Bauer method (CLSI). Eight virulence factors (FV) and six genes associated with heavy metal resistance were detected by PCR. As a result, P. aeruginosa was detected in 55% of the samples. The eight virulence factors were identified in ≥80% of the strains. The strains showed some level of resistance to only three antibiotics: 32.8% to ticarcillin, 40.8% to ticarcillin/clavulanic acid and 2.4% to aztreonam. The most frequent heavy metal resistance genes were arsC (92.8%) and copA (90.4%). However, copB and arsB genes were also identified in a percentage greater than 80%, and the least frequent genes were merA in 14.4% and czcA in 7.2%. Although P. aeruginosa strains showed a high percentage of factor virulence (potential ability to cause infections), their high levels of susceptibility to antibiotics lead to the assumption that infections are easily curable.

Resistance patterns, virulence determinants, and biofilm genes of multidrug-resistant Pseudomonas aeruginosa isolated from fish and fish handlers

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium that is widely distributed in aquatic environments and causes major economic losses in fish and public health hazards.This study aimed to identify the occurrence of P. aeruginosa in samples collected from fish and fish handlers, and to investigate the antimicrobial susceptibility, virulence determinants, and biofilm genes of P. aeruginosa isolates. A total of 276 samples were cross-sectionally collected from Nile tilapia (53), Golden grey mullet (52), Mediterranean horse mackerel (50), Striped red mullet (71), and fish handlers (50) at five different retail fish markets in Damietta Governorate, Egypt. Pseudomonas species (spp.) were biochemically identified in 57.9% of the total examined samples. Peudomonas aeruginosa were the most prevalent species isolated from the fish and human samples via PCR technique. Peudomonas aeruginosa isolates exhibited full resistance (100%) to tobramycin (TOB), gentamicin (CN), and colistin (CL), with a high level of susceptibility (88.5%) to imipenem (IPM) using the disk diffusion method. Most P. aeruginosa isolates (84.6%) exhibited drug resistance, with 61.5% were multidrug resistance (MDR) and 23.1% were extensive drug resistance (XDR). Most isolates had at least four virulence-associated genes (lasB, toxA, exoU, and oprL) and three biofilm genes (psIA, peIA, and lasR) by using uniplex PCR. The lasI, and rhlR Quorum Sensing (QS) genes were identified in 84.6% and 61.5% in the examined P. aeruginosa isolates, respectively. The highest mortality rate in Nile tilapia experimentally infected with P. aeruginosa isolate encoding most of virulent genes. Multivariate analyses revealed high heterogeneity among the examined isolates. This study revealed the emergence of virulent and drug resistant P. aeruginosa isolates in fish, poses high risks to consumers and food. Thus, strict hygienic measures should be considered when catching, handling, and storing fish, in addition to the routine application of antimicrobial susceptibility testing.

Hospital and municipal wastewater as a source of carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa in the environment: a review

The increase in the prevalence of carbapenem-resistant Gram-negative bacteria, in particular Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPA), poses a serious threat for public health worldwide. This article reviews the alarming data on the prevalence of infections caused by CRAB and CRPA pathogens and their presence in hospital and municipal wastewater, and it highlights the environmental impact of antibiotic resistance. The article describes the key role of antibiotic resistance genes (ARGs) in the acquisition of carbapenem resistance and sheds light on bacterial resistance mechanisms. The main emphasis was placed on the transfer of ARGs not only in the clinical setting, but also in the environment, including water, soil, and food. The aim of this review was to expand our understanding of the global health risks associated with CRAB and CRPA in hospital and municipal wastewater and to analyze the spread of these micropollutants in the environment. A review of the literature published in the last decade will direct research on carbapenem-resistant pathogens, support the implementation of effective preventive measures and interventions, and contribute to the development of improved strategies for managing this problem.

Pre- and Post-debridement Wound Cultures in Gustilo Type III Open Tibial Fractures to Predict Wound Infection at a Tertiary Care Hospital

BACKGROUND

Gustilo type III open tibial fractures are difficult injuries that carry a higher risk of infection and other consequences. Open-fracture wound microbiology is dynamic and responsible for change over time. Effective antibiotic treatment plans are required, as detrimental microorganisms are often linked to these types of lesions.

OBJECTIVES

The study aimed to determine whether pre- and post-debridement wound cultures could predict wound infection in Gustilo type III open tibial fractures.

METHODS

This prospective study was carried out at the National Institute of Traumatology and Orthopaedic Rehabilitation (NITOR) in Dhaka, Bangladesh, on 344 patients who presented to the emergency department with a Gustilo type III open tibial fracture within 24 hours of injury from June 2018 to October 2019. Three successive cultures were carried out: one in the emergency room (surveillance culture), the second at the emergency theater after debridement, and the third in the ward after one week (seven to 10 days). Statistical analyses of the results were conducted using Microsoft Excel (Microsoft Corp., Redmond, WA) and IBM SPSS Statistics for Windows, version 27 (IBM Corp., Armonk, NY).

RESULTS

The study included 344 patients with an average age of 37.15 years, with motor vehicle accidents being the primary cause (78.2%). Gustilo type IIIA fractures made up the majority (48.5%), followed by type IIIB fractures (44.8%). A significant reduction in contamination rates was observed from initial admission (48.8%) to post-debridement (36.6%) (p =.001). There was a significant positive correlation between pre-debridement cultures and wound infections (r =.311), as well as between post-debridement cultures and wound infections. The infection rate increased to 61.6% in ward samples, indicating a high rate of hospital-acquired infections. Pseudomonas and Klebsiella species were the most prevalent multidrug-resistant bacteria that caused these infections.

CONCLUSION

The present study provides information on the relationship between contamination and infection. Gram-negative pathogens were dominant in this study, and the results of the antibiograms showed an alarming pattern of resistance. Nosocomial infection demands further urgent study.

Metabolic Changes in Pseudomonas oleovorans Isolated from Contaminated Construction Material Exposed to Varied Biocide Treatments

Biocide resistance poses a significant challenge in industrial processes, with bacteria like Pseudomonas oleovorans exhibiting intrinsic resistance to traditional antimicrobial agents. In this study, the impact of biocide exposure on the metabolome of two P. oleovorans strains, namely, P. oleovorans P4A, isolated from contaminated coating material, and P. oleovorans 1045 reference strain, were investigated. The strains were exposed to 2-Methylisothiazol-3(2H)-one (MI) MIT, 1,2-Benzisothiazol-3(2H)-one (BIT), and 5-chloro-2-methyl-isothiazol-3-one (CMIT) at two different sub-inhibitory concentrations and the lipids and polar and semipolar metabolites were analyzed by ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry UPLC-Q-TOF/MS. Exposure to the BIT biocide induced significant metabolic modifications in P. oleovorans. Notable changes were observed in lipid and metabolite profiles, particularly in phospholipids, amino acid metabolism, and pathways related to stress response and adaptation. The 1045 strain showed more pronounced metabolic alterations than the P4A strain, suggesting potential implications for lipid, amino acid metabolism, energy metabolism, and stress adaptation. Improving our understanding of how different substances interact with bacteria is crucial for making antimicrobial chemicals more effective and addressing the challenges of resistance. We observed that different biocides trigged significantly different metabolic responses in these strains. Our study shows that metabolomics can be used as a tool for the investigation of metabolic mechanisms underlying biocide resistance, and thus in the development of targeted biocides. This in turn can have implications in combating biocide resistance in bacteria such as P. oleovorans.

Plasmid-Mediated Transfer of Antibiotic Resistance Genes in Soil

Due to selective pressure from the widespread use of antibiotics, antibiotic resistance genes (ARGs) are found in human hosts, plants, and animals and virtually all natural environments. Their migration and transmission in different environmental media are often more harmful than antibiotics themselves. ARGs mainly move between different microorganisms through a variety of mobile genetic elements (MGEs), such as plasmids and phages. The soil environment is regarded as the most microbially active biosphere on the Earth’s surface and is closely related to human activities. With the increase in human activity, soils are becoming increasingly contaminated with antibiotics and ARGs. Soil plasmids play an important role in this process. This paper reviews the current scenario of plasmid-mediated migration and transmission of ARGs in natural environments and under different antibiotic selection pressures, summarizes the current methods of plasmid extraction and analysis, and briefly introduces the mechanism of plasmid splice transfer using the F factor as an example. However, as the global spread of drug-resistant bacteria has increased and the knowledge of MGEs improves, the contribution of soil plasmids to resistance gene transmission needs to be further investigated. The prevalence of multidrug-resistant bacteria has also made the effective prevention of the transmission of resistance genes through the plasmid-bacteria pathway a major research priority.