Occurrence and Resistance Pattern of Gram-Negative Bacteremia and Sepsis in A Tertiary Care Hospital - A Four-Year Study

Antimicrobial Resistance Profile of Zoonotic Clinically Relevant WHO Priority Pathogens

The World Health Organization announced critically important bacterial and fungal pathogens displaying alarming levels of antimicrobial resistance, which currently represent difficult-to-treat cases of morbidity. Within this grouping, the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are causative of significant morbidity and mortality. Studies described herein demonstrate the presence of critically important fungal and ESKAPE bacterial species in companion animals which are zoonotic in nature. The relationship between the environment, animals, and human infectious disease has long been recognized as part of One Health. This research investigates the resistance patterns of isolated zoonotic pathogens using recognized in vitro methodologies, namely disk diffusion, minimum inhibitory concentration testing, and genetic screening. Antibiotic susceptibility testing and gene analysis demonstrated an association between multi-drug resistance and extended beta spectrum lactamase production in critical-priority bacteria. Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa exhibit great levels of multi-drug resistance. Fungal isolates demonstrated high levels of resistance, with Amphotericin B proving the most effective antifungal agent investigated. The level of antimicrobial resistance present in clinically relevant bacterial and fungal pathogens isolated from animal cases of morbidity in this study is alarming. In conclusion, this study shows that animals can act as a reservoir facilitating the transmission of antibiotic-resistant pathogens and genes zoonotically.

The Potential Predictive Role of Oxidative Stress and Antioxidant Parameters Regarding Mortality and the Type of Causative Agent in Sepsis

Oxidative stress represents an imbalance between oxidants and antioxidants, with a predominance of oxidants leading to cellular and tissue damage. Given the limited number of studies showing the predictive value of oxidative stress factors regarding sepsis type, the objectives of this study emerged as follows: to determine whether pro-oxidant and antioxidant values could predictively differentiate between Gram-positive (GP) and Gram-negative (GN) sepsis. Additionally, the study sought to assess whether bacterial type impacts treatment outcomes in sepsis patients. This prospective, observational cohort longitudinal study included 87 patients diagnosed with sepsis according to the Third International Consensus on Sepsis and Septic Shock (Sepsis-3) criteria. Following the sepsis diagnosis, blood, urine, bronchoalveolar lavage (BAL), and swabs/punctures were sampled and microbiologically analyzed. Sampling was repeated 24 hours after the first collection. Based on the microbiological results, four groups of subjects were formed: the GP group included septic patients in whom one or more GP bacteria were isolated by microbiological analysis; the GN group included septic patients in whom one or more GN bacteria were isolated; the GP/GN group included septic patients with both GP and GN bacteria isolated; and the negative culture (NC) group included septic patients in whom no pathogenic microorganisms were detected by microbiological analysis. Additionally, after sepsis diagnosis, oxidative stress markers, i.e., thiobarbituric acid reactive substances (TBARS), nitrite ion radical (NO₂⁻), hydrogen peroxide (H₂O₂), superoxide ion radical (O₂⁻), and antioxidants: superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH) were determined from blood samples. Blood sampling was repeated 24 hours after the first collection. On comparing pro-oxidant values relative to the type of infection in septic patients, measured on the first and second days, no statistically significant differences were observed for the analyzed parameters, except for delta (Δ) O₂⁻. A statistically significant increase was noted in the GN group of septic patients (p = 0.02). On comparing antioxidant values relative to infection type in septic patients, measured on the first and second days, no statistically significant differences were found for the analyzed parameters. Based on the measured values of pro-oxidants and antioxidants in this study, it is evident that they do not have predictive significance for the final treatment outcome and the type of sepsis-causing pathogen. These results underscore the need for further research on the predictive role of oxidative stress in sepsis.

Hospital Acquired Sepsis, Disease Prevalence, and Recent Advances in Sepsis Mitigation

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, commonly associated with nosocomial transmission. Gram-negative bacterial species are particularly problematic due to the release of the lipopolysaccharide toxins upon cell death. The lipopolysaccharide toxin of E. coli has a greater immunogenic potential than that of other Gram-negative bacteria. The resultant dysregulation of the immune system is associated with organ failure and mortality, with pregnant women, ICU patients, and neonates being particularly vulnerable. Additionally, sepsis recovery patients have an increased risk of re-hospitalisation, chronic illness, co-morbidities, organ damage/failure, and a reduced life expectancy. The emergence and increasing prevalence of antimicrobial resistance in bacterial and fungal species has impacted the treatment of sepsis patients, leading to increasing mortality rates. Multidrug resistant pathogens including vancomycin-resistant Enterococcus, beta lactam-resistant Klebsiella, and carbapenem-resistant Acinetobacter species are associated with an increased risk of mortality. To improve the prognosis of sepsis patients, predominantly high-risk neonates, advances must be made in the early diagnosis, triage, and control of sepsis. The identification of suitable biomarkers and biomarker combinations, coupled with machine learning and artificial intelligence, show promise in early detection protocols. Rapid diagnosis of sepsis in patients is essential to inform on clinical treatment, especially with resistant infectious agents. This timely review aims to discuss sepsis prevalence, aetiology, and recent advances towards disease mitigation and control.

Correlation of phenotypic and genotypic virulence markers, antimicrobial susceptibility pattern, and outcome of Pseudomonas aeruginosa sepsis infection

INTRODUCTION

Pseudomonas aeruginosa (PA) possesses several virulence genes that enable them to evade the immune system and to cause injury in the host tissue. However, the number of studies that characterized the virulence genes profile in PA sepsis is limited.

AIM

The main objective of this study was to identify and characterize virulence genes in PA causing sepsis, as well as investigate the relationship between virulence genes, antimicrobial susceptibility patterns, and infection outcomes.

METHODOLOGY

A prospective study, conducted between October 2020-October 2021, isolates were recovered from blood samples and identified using standard microbiological procedures. Phenotypic techniques were used to screen for capsule, siderophore production, biofilm formation, serum resistance, hemolysin production, and protease. Molecular techniques were performed to screen for alginate D (alg D), exoenzyme S (Exo S), exotoxin A (tox A), phospholipase H (plc H), phospholipase N (plc N), and elastase B (las B). Kirby-Bauer disc diffusion method was used to determine the antimicrobial susceptibility pattern of isolates, which was then interpreted according to the CLSI 2021 guidelines.

RESULTS

Out of the n = 215 Gram-negative bacteria recovered from sepsis patients during our study, n = 20 were Pseudomonas aeruginosa. PA isolates were susceptible to all antibiotics tested except for 3 of the isolates that were resistant to gentamycin, 2 to imipenem, and 1 to ceftazidime, cefepime, meropenem, tobramycin, and amikacin. The most prevalent virulence genes present were capsule (100%), siderophore production (100%), alg D (100%), Las B (100%), and Tox A (100%).

CONCLUSION

Our study found that PA causing sepsis harbours a high level of virulence genes. However, the high presence of virulence factors was not statistically associated with antimicrobial susceptibility, as most isolates in our study were susceptible to the antibiotics tested.