Preoperative oral antibiotic prophylaxis reduces Pseudomonas aeruginosa surgical site infections after elective colorectal surgery: a multicenter prospective cohort study

Antimicrobial photodynamic effect of the photosensitizer riboflavin, alone and in combination with colistin, against pandrug-resistant Pseudomonas aeruginosa clinical isolates

INTRODUCTION

Development of multi-, extensively-, and pandrug-resistant (MDR, XDR, and PDR) strains of Pseudomonas aeruginosa remains a major problem in medical care. The present study evaluated the effect of antimicrobial photodynamic therapy (aPDT) as a monotherapy and in combination with colistin against P. aeruginosa isolates.

METHODS

Two P. aeruginosa isolates recovered from patients with respiratory tract infections were examined in this study. Minimum inhibitory concentration (MIC) of colistin was determined by the colistin broth disk elution (CBDE) and the reference broth microdilution (rBMD) methods. aPDT was performed using the photosensitizer (Ps) riboflavin at several concentrations and a light-emitting diode (LED) emitting blue light for different irradiation times with or without colistin at 1/2 × MIC concentration.

RESULTS

Both PA1 and PA2 isolates were identified as colistin-resistant P. aeruginosa with a MIC ≥4 μg/mL by the CBDE and MICs of 512 μg/mL and 256 μg/mL, respectively, by the rBMD. In aPDT, neither riboflavin nor LED light alone had antibacterial effects. The values of colony forming units per milliliter (CFU/mL) in both isolates were significantly reduced by LED + Ps treatments in a time-dependent manner (LED irradiation time) and dose-dependent manner (Ps concentration). In comparison with control, treatment with Ps (50 μM) + LED (120 s) and Ps (100 μM) + LED (120 s) resulted in 0.27 log10 CFU/mL and 0.43 log10 CFU/mL reductions in PA1, and 0.28 log10 CFU/mL and 0.34 log10 CFU/mL reductions in PA2, respectively, (P < 0.01). The best results were obtained after the combination of aPDT followed by colistin, which increased bacterial reduction, resulting in a 0.41-0.7 log10 CFU/mL reduction for PA1 and 0.35-0.83 log10 CFU/mL reduction for PA2 (P = 0.001).

CONCLUSIONS

This study suggests the potential implications of aPDT in combination with antibiotics, such as colistin for treatment of difficult-to-treat P. aeruginosa infections.

Bacteriophages and Green Synthesized Zinc Oxide Nanoparticles in Combination Are Efficient against Biofilm Formation of Pseudomonas aeruginosa

Bacteriophages (phages) are viruses that infect the bacteria within which their reproduction cycle takes place, a process that ends in the lysis and death of the bacterial cell. Some phages are also able to destroy bacterial biofilms. Due to increased antibiotics resistance, Pseudomonas aeruginosa, another biofilm-forming pathogen, is a problem in many parts of the world. Zinc oxide (ZnO) and other metal nanoparticles (NPs) are biologically active and also possess anti-biofilm properties. ZnO-NPs were prepared by the green synthesis method using orange peels. The vibrational peaks of the ZnO-NPs were analyzed using FTIR analysis, and their size and morphological properties were determined using scanning electron microscopy (SEM). The ability of the ZnO-NPs to reduce or eliminate P. aeruginosa biofilm alone or in combination with phages PB10 and PA19 was investigated. The P. aeruginosa cells were effectively killed in the preformed 48 h biofilms during a 24 h incubation with the ZnO-NP-phage combination, in comparison with the control or ZnO-NPs alone. The treatments on growing biofilms were most efficient in the final stages of biofilm development. All five treatment groups showed a significant biofilm reduction compared to the control group (p < 0.0001) at 48 h of incubation. The influence of the ZnO-NPs and phages on the quorum sensing system of P. aeruginosa was monitored by quantitative real-time PCR (qRT-PCR) of the autoinducer biosynthesis gene lasI. While the ZnO-NPs repressed the lasI gene transcription, the phages slightly activated it at 24 and 48 h of incubation. Also, the effect of the ZnO-NPs and phage PA19 on the viability of HFF2 cells was investigated and the results showed that the combination of NPs with PA19 reduced the toxic effect of ZnO-NPs and also stimulated the growth in normal cells.

Efficacy and safety of oral probiotic supplementation in mitigating postoperative surgical site infections in patients undergoing colorectal cancer surgery: A systematic review and meta-analysis

Surgical site infections (SSIs) pose significant risks to patients undergoing colorectal cancer (CRC) surgery. With increasing evidence on the benefits of oral probiotics in various clinical contexts, there is a need to assess their efficacy and safety in reducing SSIs following CRC surgery. A systematic review and meta-analysis were conducted in line with PRISMA guidelines using the PICO framework. On 19 September 2023, four major databases (PubMed, Embase, Web of Science and Cochrane Library) were searched without any temporal or language restrictions. Rigorous inclusion and exclusion criteria were employed. Data extraction was independently undertaken by two assessors, and any discrepancies were discussed. The Cochrane Collaboration's risk of bias instrument was utilized to assess study quality. The meta-analysis incorporated a fixed-effects model or random-effects model based on the I2 statistic to assess heterogeneity. The initial search yielded 1282 articles, of which 10 met the inclusion criteria and were analysed. Probiotic administration not only significantly reduced the incidence of SSIs but also curtailed the duration of hospital stays. Moreover, the subgroup analysis indicated that interventions employing multiple strains of probiotics were more effective in reducing postoperative infections than those utilizing a single strain. Probiotics effectively prevent postoperative infections and shorten hospital stays. Multi-strain probiotics outperform single strain in efficacy. Future studies should focus on their safety and optimal clinical use.

Introduce a novel post-biotic against Pseudomonas aeruginosa biofilm formation using Escherchia coli Nissle1917 outer membrane vesicles

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that can cause acute infections as well as chronic ones in humans. The expression of algD and PpyR genes involved in biofilm formation in clinical isolates of P. aeruginosa in the presence of Escherichia coli Nissle1917 outer membranes vesicles (EcN OMVs) was evaluated. All isolates were tested for biofilm formation. qPCR and disk diffusion were used to identify the expression of algD and PpyR genes, and antimicrobial resistance, respectively. EcN OMVs caused a more significant loss of algD and PpyR expression, compared with the control group. EcN OMVs contain a variety of biomolecules that are capable of influencing the biofilm formation genes. EcN OMVs treatment reduced P. aeruginosa biofilm formation significantly, which emphasizes their positive role in inhibiting biofilm formation. As a result, EcN OMVs can be used as new therapeutic strategies for inhibiting P. aeruginosa biofilm formation.

Pseudomonas aeruginosa: Infections and novel approaches to treatment "Knowing the enemy" the threat of Pseudomonas aeruginosa and exploring novel approaches to treatment

Pseudomonas aeruginosa is an aerobic Gram-negative rod-shaped bacterium with a comparatively large genome and an impressive genetic capability allowing it to grow in a variety of environments and tolerate a wide range of physical conditions. This biological flexibility enables the P. aeruginosa to cause a broad range of infections in patients with serious underlying medical conditions, and to be a principal cause of health care associated infection worldwide. The clinical manifestations of P. aeruginosa include mostly health care associated infections and community-acquired infections. P. aeruginosa possesses an array of virulence factors that counteract host defence mechanisms. It can directly damage host tissue while utilizing high levels of intrinsic and acquired antimicrobial resistance mechanisms to counter most classes of antibiotics. P. aeruginosa co-regulates multiple resistance mechanisms by perpetually moving targets poses a significant therapeutic challenge. Thus, there is an urgent need for novel approaches in the development of anti-Pseudomonas agents. Here we review the principal infections caused by P. aeruginosa and we discuss novel therapeutic options to tackle antibiotic resistance and treatment of P. aeruginosa infections that may be further developed for clinical practice.

Defeating a superbug: A breakthrough in vaccine design against multidrug-resistant Pseudomonas aeruginosa using reverse vaccinology

BACKGROUND

Multidrug-resistant Pseudomonas aeruginosa has become a major cause of severe infections. Due to the lack of approved vaccines, this study has presented putative vaccine candidates against it.

METHODS

P. aeruginosa 24Pae112 as a reference strain was retrieved from GenBank database. The surface-exposed, antigenic, non-allergenic, and non-homologous human proteins were selected. The conserved domains of selected proteins were evaluated, and the prevalence of proteins was assessed among 395 genomes. Next, linear and conformational B-cell epitopes, and human MHC II binding sites were determined. Finally, five conserved and highly antigenic B-cell epitopes from OMPs were implanted on the three platforms as multi-epitope vaccines, including FliC, the bacteriophage T7 tail, and the cell wall-associated transporter proteins. The immunoreactivity was investigated using molecular docking and immune simulation. Furthermore, molecular dynamics simulation was done to refine the chimeric cell-wall-associated transporter-TLR4 complex as the best interaction.

RESULTS

Among 6494 total proteins of P. aeruginosa 24Pae112, 16 proteins (seven OMPs and nine secreted) were ideal according to the defined criteria. These proteins had a molecular weight of 110 kDa and were prevalent in ≥ 75% of P. aeruginosa genomes. Among the presented multi-epitope vaccines, the chimeric cell-wall-associated transporter had the strongest interaction with TLR4. Moreover, the immune simulation response revealed that the bacteriophage T7 tail chimeric protein had the strongest ability to stimulate the immune system. In addition, molecular docking and molecular dynamic simulation indicated the proper and stable interactions between the chimeric cell-wall-associated transporter and TLR4.

CONCLUSION

This study proposed 16 shortlisted proteins as promising immunogenic targets. Two novel platforms (e.g. cell-wall-associated transporter and bacteriophage T7 tail proteins) for designing of multi-epitope vaccines (MEVs), showed the better performance compared to FliC. In our future studies, these two MEVs will receive more scrutiny to evaluate their immunoreactivity.

Association of multidrug resistance behavior of clinical Pseudomonas aeruginosa to pigment coloration

Pseudomonas aeruginosa is an adaptable bacterial pathogen that infects a variety of organs, including the respiratory tract, vascular system, urinary tract, and central nervous system, causing significant morbidity and mortality. As the primary goal of this study, we wanted to determine how pigment color production differed between clinical strains of P. aeruginosa, and whether or not that variation was associated with multidrug resistance or the ability to form biofilms. We screened in total 30.1% of yellow, 39.8% green and 30.1% of no pigment-producing P. aeruginosa strains from a total of 143 various clinical isolates. Yellow pigment-producing strains presented significant resistance to antibiotics groups, including β-lactam (91.5%), aminoglycosides (70.5%), and carbapenems (51.9%) compared to green and non-pigmented strains. Notably, 16.3% of yellow pigment-producing strains were resistant to colistin which is used as a last-resort treatment for multidrug-resistant bacteria, whereas only 2.3% of non-pigmented and 1.8% of green pigmented strains were resistant to colistin. Aside from that, yellow pigment-producing strains were frequent producers of enzymes belonging to the lactamase family, including ESBL (55.6%), MBL (55.6%), and AmpC (50%). Compared to the green groups (7.14%) and non-pigmented groups (28.5%), they had a higher frequency of efflux positive groups (64.2%). Notably, when compared to non-pigmented groups, green pigment-producing strains also displayed antibiotic susceptibility behavior similar to yellow pigment-producing strains. The majority of yellow pigment-producing strains outperformed the green and non-pigmented strains in terms of MIC levels when compared to the other two groups of strains. Despite the fact that previous studies have demonstrated a direct correlation between multidrug resistance behaviors and biofilm production, no such statistically significant association between pigment and biofilm formation was found in our investigation. Our research has demonstrated that the correlation of bacterial pigments on their susceptibility to antimicrobial agents. Yellow pigment-producing P. aeruginosa strains posed a significant problem due to the lack of alternative agents against such transformed strains, which may be associated with the development of multidrug resistance.

OUP accepted manuscript

Background

The prognosis of patients with metastatic malignant melanoma is very poor and partly due to resistance to conventional chemotherapies. The study’s objectives were to assess the activity and tolerability of apatinib, an oral small molecule anti-angiogenesis inhibitor, in patients with recurrent advanced melanoma.

Methods

This was a single-arm, single-center phase II trial. The primary endpoint was progression-free survival (PFS) and the secondary endpoints were objective response rate (ORR), disease control rate (DCR), and overall survival (OS). Eligible patients had received at least one first-line therapy for advanced melanoma and experienced recurrence. Apatinib (500 mg) was orally administered daily.

Results

Fifteen patients (V660E BRAF status: 2 mutation, 2 unknown, 11 wild type) were included in the analysis. The median PFS was 4.0 months. There were two major objective responses, for a 13.3% response rate. Eleven patients had stable disease, with a DCR of 86.7%. The median OS was 12.0 months. The most common treatment-related adverse events of any grade were hypertension (80.0%), mucositis oral (33.3%), hand-foot skin reaction (26.7%), and liver function abnormalities, hemorrhage, diarrhea (each 20%). The only grade ≥3 treatment-related adverse effects that occurred in 2 patients was hypertension (6.7%) and mucositis (6.7%). No treatment-related deaths occurred.

Conclusion

Apatinib showed antitumor activity as a second- or above-line therapy in patients with malignant melanoma. The toxicity was manageable.

ClinicalTrials.gov Identifier

NCT03383237

Preoperative oral antibiotics with versus without mechanical bowel preparation to reduce surgical site infections following colonic resection: Protocol for an international randomized controlled trial (ORALEV2)

AIM

Surgical site infections (SSIs) are common after colonic surgery. SSIs can cause relevant morbidity and increase costs of care. Preoperative oral antibiotics can reduce the incidence of SSIs after resection of the colon, but the role of mechanical bowel preparation (MBP) is debated. This study aims to assess the impact of a combined regimen of oral antibiotics and MBP on SSIs after colonic surgery.

METHODS

An international, multicentre, pragmatic, adaptive, parallel-group, randomized controlled trial will be conducted across Europe. Adult patients scheduled to undergo elective colonic resection will be assessed for inclusion. Patients will be randomized into one of two treatment arms: (1) preoperative oral antibiotics without MBP (control); (2) preoperative oral antibiotics with MBP (experimental). All patients will receive intravenous antibiotics at anaesthetic induction. The primary aim will be 30-day SSI, assessed by a blinded nurse. Additional end-points include safety, morbidity and mortality, satisfaction with the preparation, time to return of bowel function, time to complete recovery and time to discharge, long-term results. Analyses will be performed with a modified intention-to-treat approach. Interim analyses are planned.

DISCUSSION

This will be the first randomized clinical trial to assess the efficacy and safety of preoperative oral antibiotics plus MBP versus preoperative oral antibiotics only, before colonic surgery. The knowledge obtained could help to establish the ideal preparation for patients scheduled to undergo resection of the colon. Full protocol NCT04161599.

Is sterile exposure in perianal procedures necessary? A single-institution experience and results from a national survey

BACKGROUND

Surgical site infections (SSI) are the most common postoperative complications. To minimize the risk of SSI, there is a strict asepsis policy in the operating theatre. The aim of this study was to evaluate the risk and cost-saving benefit of performing perianal surgery in a non-sterile setting.

METHODS

All patients who had perianal surgery at our institution between January 2014 and December 2017 in a sterile (S) or non-sterile (NS) setting for an infectious or non-infectious cause were included. The primary outcome was the 30-day SSI rate. The secondary outcome was the reintervention rate. A questionnaire was sent to surgeons in the Netherlands to assess current policy with regard to asepsis in perianal procedures. Finally, a cost analysis was performed.

RESULTS

In total, 376 patients were included. The rate of SSI in infectious procedures was 13% (S) versus 14% (NS, p = 0.853) and 5.1% (S) versus 0.9% (NS) in non-infectious procedures (p = 0.071). Reintervention rates in infectious procedures were 3.4% (S) versus 8.6% (NS, p = 0.187) and 1.3% (S) versus 0.0% (NS) in non-infectious procedures (p = 0.227). The questionnaire revealed that most surgeons perform perianal surgery in a sterile setting although they did not consider this useful. The potential national cost-saving benefit of a non-sterile setting is €124.61 per patient.

CONCLUSIONS

This study suggests that it is safe to perform perianal surgery in a non-sterile setting with regard to the SSI and reintervention rate. Adjustment of the current practice will contribute to a reduction in healthcare expenses.

Surgical wound infection prevention using topical negative pressure therapy on closed abdominal incisions - the 'SWIPE IT' randomized clinical trial

BACKGROUND

Surgical site infections (SSIs) are the most common cause of healthcare-associated infections in surgical patients. It is unclear whether incisional negative pressure wound therapy (NPWT) can reduce the risk of SSIs in patients after open abdominal surgery.

METHODS

A prospective, non-blinded multi-centre randomized controlled trial (RCT) was performed to evaluate the incidence of SSI post-laparotomy using incisional NPWT compared with a standard dressing. The primary outcome was the rate of superficial SSI.

RESULTS

A total of 124 patients (61 patients in the NPWT arm and 63 patients in the control arm) were included. One hundred and nine (87.9%) patients underwent colorectal surgery; 61 patients (49.2%) had emergency surgery. There were more superficial SSIs in the control group than in the NPWT group, although not statistically significant (20.6% vs 9.8%, P=0.1). Upon multiple logistic regression analysis, control dressings were associated with increased risk of superficial SSI although again, not statistically significant (odds ratio (OR) 2.41, 95% confidence interval (CI) 0.81-7.17, P=0.11). There was no superficial non-SSI related wound dehiscence in the NPWT group compared with 9.5% in the control group (P=0.03). There was no difference in postoperative complications (P=0.15), nor in other wound complications (P=0.79).

CONCLUSION

NPWT was not associated with decreased superficial SSI in this RCT. However, there was a statistically significant reduction in superficial wound dehiscence with NWPT dressings. The results of this study should be included in meta-analyses for better evaluation of NPWT on closed abdominal incisions.

New Clinical Applications of Electrolyzed Water: A Review

As the situation of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is still deteriorating, there has been a huge increase in the demand and use of disinfectants. Electrolyzed water (EW), as a novel broad-spectrum disinfectant and cleaner, has been widely used for several years. EW can be produced in an electrolysis chamber which contains dilute salt and tap water. It is an effective antimicrobial and antibiofilm agent, with several advantages such as on-the-spot, cheap, environmentally friendly and safe for human beings. Therefore, EW holds potential significance for high-risk settings in hospitals and other clinical facilities. EW can also be applied for wound healing, advanced tissue care, and dental clinics. The present review article highlights the latest developments and new perspectives of EW, especially in clinical fields. Furthermore, the main action modes of antibiofilm and antimicrobial will be summarized.

Pseudomonas aeruginosa Biofilms

Pseudomonas aeruginosa is an opportunistic human pathogen causing devastating acute and chronic infections in individuals with compromised immune systems. Its highly notorious persistence in clinical settings is attributed to its ability to form antibiotic-resistant biofilms. Biofilm is an architecture built mostly by autogenic extracellular polymeric substances which function as a scaffold to encase the bacteria together on surfaces, and to protect them from environmental stresses, impedes phagocytosis and thereby conferring the capacity for colonization and long-term persistence. Here we review the current knowledge on P. aeruginosa biofilms, its development stages, and molecular mechanisms of invasion and persistence conferred by biofilms. Explosive cell lysis within bacterial biofilm to produce essential communal materials, and interspecies biofilms of P. aeruginosa and commensal Streptococcus which impedes P. aeruginosa virulence and possibly improves disease conditions will also be discussed. Recent research on diagnostics of P. aeruginosa infections will be investigated. Finally, therapeutic strategies for the treatment of P. aeruginosa biofilms along with their advantages and limitations will be compiled.

Surgical complications in colorectal cancer patients

BACKGROUND

Advancements in diagnostic and therapeutic sciences have allowed early diagnosis and treatment of cancer. Colorectal cancer is one of the most commonly reported cancers, particularly in elderly patients.

METHODS

Open and laparoscopic surgeries are used for the removal of the tumor, along with chemotherapy, depending on the stage of cancer. However, colorectal cancer surgery is associated with a great number of complications, that affect the efficacy of the surgery and overall health and survival of the patient.

RESULTS

Prevalence of these complications have shown discrepancies depending on the condition of the patient and disease and surgical skills of the surgeon. Preoperative evaluation, intraoperative care and postoperative measures can reduce the incidence of these complications.

CONCLUSION

This review highlights some frequently reported complications associated with colorectal cancer surgery, their risk factors and subsequent therapeutic measures to treat them.

The close interrelation between colorectal cancer, infection and microbiota

PURPOSE OF REVIEW

Evaluate the recent literature about the relation of clinical infection and colorectal cancer in terms of diagnosis of an occult infection and possible impact on oncological outcome and review the possible role of the gut microbiota in the role of colorectal cancer oncogenesis.

RECENT FINDINGS

Data published within the 2 last years have been reviewed and the conclusions, mostly supporting previously published information, have been critically discussed.

SUMMARY

Infection (bacteremia, cellulitis) might be a surrogate of occult colorectal cancer and postoperative infection complications might jeopardize long-term survival after potentially curative surgery. The role of the gut microbiota in the genesis of colorectal cancer remains an exciting though unresolved question.