Three Year Study of Infection Profile and Antimicrobial Resistance Pattern from Burn Patients in Southwest Iran

Antibacterial Properties and Efficacy of LL-37 Fragment GF-17D3 and Scolopendin A2 Peptides Against Resistant Clinical Strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii In Vitro and In Vivo Model Studies

Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter baumannii have emerged as major clinical threats owing to the increasing prevalence of ventilator-associated pneumonia caused by multidrug-resistant or extensively drug-resistant strains. The present study aimed to assess the antibacterial effects and efficacy of LL-37 fragment GF-17D3 and synthetic Scolopendin A2 peptides against resistant clinical strains in vitro and in vivo models. P. aeruginosa, S. aureus, and A. baumannii were isolated from clinical infections. Their antibiotic resistance and minimum inhibitory concentration were assessed. LL-37 fragment GF-17D3 peptide was selected from available databases. Scolopendin A2 peptide's 6th amino acid (proline) was substituted with lysine and peptides and MICs were determined. The biofilm inhibitory activity was quantified at sub MIC concentrations. Synergetic effects of Scolopendin A2 and imipenem were assessed by checkerboard. After mice nasal infection with P. aeruginosa, peptides LD50 was determined. Isolates harbored complete resistance toward the majority of antibiotics and MIC values ranged between 1 and > 512 µg/ml. The majority of isolates exhibited strong biofilm activity. Synthetic peptides showed lower MIC values than antibiotic agents and the lowest MIC values were obtained for synthetic peptides in combination with antibiotics. The Synergisms effect of Scolopendin A2 with imipenem was also determined. Scolopendin A2 was found to have antibacterial efficacy against P. aeruginosa, S. aureus, and A. baumannii with MIC 64 µg/ml, 8 µg/ml, and 16 µg/ml, respectively, and LL37 showed antibacterial efficacy against P. aeruginosa, S. aureus, and A. baumannii with MIC 128 µg/ml, 32 µg/ml, and 32 µg/ml, respectively. Both AMPs decreased biofilms by ≥ 96% at 1 × MIC. The biofilm inhibitory activity was measured at sub MIC concentrations of the peptides and the results demonstrated that Scolopendin A2 exhibited anti-biofilm activity at 1/4 × MIC and 1/2 × MIC concentrations was 47.9 to 63.8%, although LL37 among 1/4 × MIC and 1/2 × MIC concentrations was 21.3 to 49.6% against three pathogens. The combination of Scolopendin A2 and antibiotics demonstrated synergistic activity-resistant strains with FIC values ≤ 0.5 for three pathogens, while LL37 and antibiotics showed synergistic activity FIC values ≤ 0.5 for only P. aeruginosa. Infection model Scolopendin A2 with Imipenem (2 × MIC) was efficacious in vivo, with a 100% survival rate following treatment at 2 × MIC after 120 h. The mRNA expression of biofilm-related genes was decreased for both peptides. Synthesis Scolopendin A2 decreased the expression of biofilm formation genes compared to the control group. Synthetic Scolopendin A2 exhibits antimicrobial activity without causing toxicity on the human epithelial cell line. Based on our findings, it seems that synthetic Scolopendin A2 is an appropriate antimicrobial source. That could be a promising option in combination with antibiotics for a topical medication and in the prevention of acute and chronic infections caused by multidrug-resistant bacteria. Nevertheless, additional experiments are required to assess another potential of this novel AMP.

Detection of Inflammatory Biomarkers Among Patients with Sepsis of Gram-Negative Bacteria: A Cross-Sectional Study

Background

Sepsis is a highly mixed ailment that affects patients with numerous conditions of infectious sources and can lead to multi-organ failure with dysregulated host immune response.

Objective

To determine inflammatory biomarkers in patients with sepsis caused by Gram-negative bacteria and compare their role in the early detection of sepsis.

Methods

This cross-sectional study was conducted on patients with sepsis admitted to the intensive care unit at different hospitals in Sulaimaniyah, Iraq, from May to December 2021. Patients (n=147) were enrolled in this study according to the primary diagnosis of sepsis by Sequential Organ Failure Assessment scores. Blood samples were taken from patients to investigate white blood cells, inflammatory biomarkers (pentraxin-3, procalcitonin, adrenomedullin, lipopolysaccharide binding protein, interleukin-17A, lactate dehydrogenase, and C-creative protein), blood culture, antibiotic susceptibility test, and coagulation biomarkers (Prothrombin time, activated partial thromboplastin time, and international normalized ratio). Then, isolated Gram-negative bacteria were tested for extended-spectrum β-lactamase enzymes production by screening and combined disc tests.

Results

A total of 51.7% samples were blood culture positive for different Gram-negative bacteria, and P. aeruginosa (51.95%) was a more isolated bacterium. Both males and females were affected by sepsis in a ratio of 1.23:1 with different age groups. Extended-spectrum β-lactamase was estimated to be 77.2% by antibiotic profile, and the rate decreased using two double-disc synergy tests. This was confirmed by combined disc test at a rate of 41.35%. The most prevalent biomarkers were procalcitonin (88.16%), adrenomedullin (84.21%), pentraxin-3 (22.37%), and lipopolysaccharide binding protein (11.84%).

Conclusion

Sepsis is a life-threatening condition that can be diagnosed early by several blood biomarkers such as procalcitonin, adrenomedullin, and pentraxin-3 combined with a standard blood culture technique to improve the patient outcome.

Pseudomonas aeruginosa: Infections, Animal Modeling, and Therapeutics

Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen which causes many severe acute and chronic infections with high morbidity, and mortality rates as high as 40%. What makes P. aeruginosa a particularly challenging pathogen is its high intrinsic and acquired resistance to many of the available antibiotics. In this review, we review the important acute and chronic infections caused by this pathogen. We next discuss various animal models which have been developed to evaluate P. aeruginosa pathogenesis and assess therapeutics against this pathogen. Next, we review current treatments (antibiotics and vaccines) and provide an overview of their efficacies and their limitations. Finally, we highlight exciting literature on novel antibiotic-free strategies to control P. aeruginosa infections.

Prevalence of multidrug-resistant bacteria associated with polymicrobial infections

BACKGROUND

Wounds remain the most important cause of postoperative mortality and morbidity and generate considerable additional social and healthcare costs. Most wounds are caused by various coliforms, Enterococcus fecalis, Proteus sp., and multidrug resistant Staphylococcus aureus. Wound is one of the leading cause of infections in the under developed and developing countries than developed nations.

METHODS

A total of 43 samples associated with bacteremia and wound infection were collected. Biochemical characterization and culture characteristics of the drug resistant isolates were studied using MacConkey agar, blood agar and mannitol-salt agar. Antibiotic susceptibility analysis of the isolated strains was performed by disc diffusion method using various antibiotics. Prevalence of dug resistance among bacteria isolated from the wound was studied. The ability of Beta lactamase antibiotic producing bacterial strains were analyzed.

RESULTS

A total of 168 bacterial strains were isolated showed high resistant towards ampicillin (89%), ciprofloxacin (90.8), cefepine (90.5), piperacillin (91.8), oxacillin (92.5), and imipenem (96.5). The isolated bacterial strains showed monobacterial as well as polybacterial growth on the surface of the wound. The isolated bacterial strains revealed 89% sensitivity against norfloxacin and 94.9 sensitivity against vancomycin. About 26% of bacterial strains degraded quinolones, whereas only 14% clinical isolates showed their ability to degrade aminoglycosides. A total of 27% bacteria degraded tetracycline and 51% of isolates degraded carbapenems compounds. Interestingly, E. faecalis was resistant against antibiotics such as, Oxacillin, Nalidic acid, Ofloxacin, Erythromycin, Norfloxacin, Ciprofloxacin, Ampicillin, Tetracycline, Cefepine, Amikacin, Cefurooxime, Vancomycin, Piperacillin, Imipenem and Gentamycin. Moreover, Proteus species was resistant against certain numbers of antibiotics namely, Ampicillin, Piperacillin, Oxacillin, Nalidic acid, Tetracycline, Erythromycin, Cefurooxime, Nitrofurantoin, Vancomycin and Imipenem.

CONCLUSIONS

The isolated bacterial strains were resistant against various drugs including vancomycin. Staphylococci, and E. faecalisis strains showed resistance against various classes of antibiotics.

High Level of Multidrug-Resistant Gram-Negative Pathogens Causing Burn Wound Infections in Hospitalized Children in Dar es Salaam, Tanzania

Background

Bacterial infection remains the most common cause of morbidity and mortality in pediatric patients with burn wounds. The increase in infection and multidrug-resistant (MDR) pathogens necessitates a periodic review of antimicrobial susceptibility patterns in the burn units. The study aimed to determine the magnitude of multidrug-resistant Gram-negative (MDRGN) bacteria in children with burn wound infections and describe the resistance patterns in the tertiary and regional hospitals in Dar es Salaam, Tanzania.

Materials and Methods

The study was a hospital-based cross-sectional study design conducted between May 2017 and February 2018. Bacterial isolates from 103 wound swabs of pediatric patients with burn wounds were identified using conventional methods and API 20E. The antimicrobial susceptibility pattern was determined by the Kirby-Bauer disc diffusion method. Data were analyzed using Statistical Package for Social Science (SPSS) version 23.0.

Results

A total of 136 pathogenic Gram-negative organisms were isolated from burn wound infections in pediatric patients. The most isolated Gram-negative bacterium was Pseudomonas aeruginosa (39.0%), followed by Acinetobacter spp. (28.7%) and Klebsiella spp. (16.2%). MDRGN strains made up 80.1% of all Gram-negative isolates. All (100%) Klebsiella spp. and E. coli were MDR, while 69.2% and 79.2% of Acinetobacter spp. and P. aeruginosa, respectively, displayed MDR strains. We observed high levels of resistance to commonly prescribed antibiotics. Among P. aeruginosa isolates, highest resistance (81.8%) was seen toward meropenem and piperacillin, 79.5% of Acinetobacter spp. showed resistance to aztreonam, while 93-100% of Klebsiella spp and E. coli displayed resistance to amoxyclavulanic acid, ceftriaxone, and ceftazidime. The proportion of extended-spectrum beta-lactamase producers among Enterobacteriaceae was 78.6%. There was a significant higher rate of infection with MDRGN organisms in pediatric patients with a higher percentage of total burn surface area (TBSA) than patients with lower TBSA (p = 0.016).

Conclusions

P. aeruginosa, Acinetobacter spp., and Klebsiella spp. are the common Gram-negative pathogens causing burn wound infections in hospitalized pediatric patients in our setting. A high proportion of these organisms were multidrug resistant. The findings appeal for regular antimicrobial resistance surveillance in burn wound infection to inform empirical therapy.

Different Infection Profiles and Antimicrobial Resistance Patterns Between Burn ICU and Common Wards

Infection is the leading cause of complications and deaths after burns. However, the difference in infection patterns between the burn intensive care unit (BICU) and burn common wards (BCW) have not been clearly investigated. The present study aimed to compare the infection profile, antimicrobial resistance, and their changing patterns in burn patients in BICU and BCW. Clinical samples were analyzed between January 1, 2011, and December 31, 2019, in the Institute of Burn Research in Southwest China. The patient information, pathogen distribution, sources, and antimicrobial resistance were retrospectively collected. A total of 3457 and 4219 strains were detected in BICU and BCW, respectively. Wound secretions accounted for 86.6% and 44.9% in BCW and BICU, respectively. Compared with samples in BCW, samples in BICU had more fungi (11.8% vs. 8.1%), more Gram-negative bacteria (60.0% vs. 50.8%), and less Gram-positive bacteria (28.2% vs. 41.1%). Acinetobacter baumannii were the most common pathogen in BICU, compared with Staphylococcus aureus in BCW. S. aureus was the most frequent pathogen in wound secretions and tissues from both BICU and BCW. However, A. baumannii were the first in blood, sputum, and catheter samples from BICU. Overall, the multidrug-resistance (MDR) rate was higher in BICU than in BCW. However, the gap between BICU and BCW gradually shortened from 2011 to 2019. The prevalence of MDR A. baumannii and Klebsiella pneumonia significantly increased, especially in BCW. Furthermore, Carbapenem resistance among K. pneumoniae significantly increased in BICU (4.5% in 2011 vs. 40% in 2019) and BCW (0 in 2011 vs. 40% in 2019). However, the percentage of MDR P. aeruginosa sharply dropped from 85.7% to 24.5% in BICU. The incidence of MRSA was significantly higher in BICU than in BCW (94.2% vs. 71.0%) and stayed at a high level in BICU (89.5% to 96.3%). C. tropicalis and C. albicans were the two most frequent fungi. No resistance to Amphotericin B was detected. Our study shows that the infection profile is different between BICU and BCW, and multidrug resistance is more serious in BICU than BCW. Therefore, different infection-control strategies should be emphasized in different burn populations.