Repression of resistance mechanisms of Pseudomonas aeruginosa: implications of the combination of antibiotics and phytoconstituents

Antimicrobial resistance is a prevalent problem witnessed globally and creating an alarming situation for the treatment of infections caused by resistant pathogens. Available armaments such as antibiotics often fail to exhibit the intended action against resistant pathogens, leading to failure in the treatments that are causing mortality. New antibiotics or a new treatment approach is necessary to combat this situation. P. aeruginosa is an opportunistic drug resistant pathogen and is the sixth most common cause of nosocomial infections. P. aeruginosa due to its genome organization and other factors are exhibiting resistance against drugs. Bacterial biofilm formation, low permeability of outer membrane, the production of the beta-lactamase, and the production of several efflux systems limits the antibacterial potential of several classes of antibiotics. Combination of phytoconstituents with antibiotics is a promising strategy to combat multidrug resistant P. aeruginosa. Phytoconstituents such as flavonoids, terpenoids, alkaloids, polypeptides, phenolics, and essential oils are well known antibacterial agents. In this review, the activity of combination of the phytoconstituents and antibiotics, and their corresponding mechanism of action was discussed elaborately. The combination of antibiotics and plant-derived compounds exhibited better efficacy compared to antibiotics alone against the antibiotic resistance P. aeruginosa infections.

Acinetobacter baumannii: an evolving and cunning opponent

Acinetobacter baumannii is one of the most common multidrug-resistant pathogens causing nosocomial infections. The prevalence of multidrug-resistant A. baumannii infections is increasing because of several factors, including unregulated antibiotic use. A. baumannii drug resistance rate is high; in particular, its resistance rates for tigecycline and polymyxin-the drugs of last resort for extensively drug-resistant A. baumannii-has been increasing annually. Patients with a severe infection of extensively antibiotic-resistant A. baumannii demonstrate a high mortality rate along with a poor prognosis, which makes treating them challenging. Through carbapenem enzyme production and other relevant mechanisms, A. baumannii has rapidly acquired a strong resistance to carbapenem antibiotics-once considered a class of strong antibacterials for A. baumannii infection treatment. Therefore, understanding the resistance mechanism of A. baumannii is particularly crucial. This review summarizes mechanisms underlying common antimicrobial resistance in A. baumannii, particularly those underlying tigecycline and polymyxin resistance. This review will serve as a reference for reasonable antibiotic use at clinics, as well as new antibiotic development.

A retrospective evaluation of multiple definitions for ventilator associated pneumonia (VAP) diagnosis in an Australian regional intensive care unit

BACKGROUND

Ventilator Associated Pneumonia is a common complication of invasively ventilated patients with significant and underestimated morbidity and mortality. Defining VAP cases is greatly varied as many definitions are used with varying success and sensitivity. This study evaluates VAP detection using four definitions in a regional Australian Intensive Care Unit (ICU).

METHODS

A cohort of patients admitted to ICU at the Mackay Base Hospital from April 1st 2020 to March 31st 2021, who had endo-tracheal intubation and mechanical ventilation for longer than 48 h were identified. Each patient was examined across four common definitions of VAP. Head-to-head analysis of definitions was pursued to determine the most suitable definition. The four definitions used included: An Australian VAP definition, the CDC VAP definition, the Mackay Base Hospital Local Protocol and a Physician Decision Arm.

RESULTS

66 unique patients and 2 re-intubations were identified during the data collection window. The local protocol identified 8 cases of VAP. The Australian VAP definition identified 6 additional cases and 0 missed cases compared to the local protocol. The CDC definition missed 4 cases and identified 4 additional cases compared to the local protocol. Finally, the physician arm identified 10 cases including 8 additional cases and missed 6 cases.

CONCLUSIONS

VAP is an extremely difficult clinical condition to define and detect. Definitions have varied accuracy and suffer logistically for application to the individual patient. Refined criteria for diagnosis of VAP is greatly needed and its prevalence in intensive care units likely remains uncertain.

Antibacterial activity of medicinal plants against ESKAPE: An update

Antibiotic resistance has emerged as a threat to global health, food security, and development today. Antibiotic resistance can occur naturally but mainly due to misuse or overuse of antibiotics, which results in recalcitrant infections and Antimicrobial Resistance (AMR) among bacterial pathogens.

These mainly include the MDR strains (multi-drug resistant) of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). These bacterial pathogens have the potential to “escape” antibiotics and other traditional therapies. These bacterial pathogens are responsible for the major cases of Hospital-Acquired Infections (HAI) globally. ESKAPE Pathogens have been placed in the list of 12 bacteria by World Health Organisation (WHO), against which development of new antibiotics is vital. It not only results in prolonged hospital stays but also higher medical costs and higher mortality. Therefore, new antimicrobials need to be developed to battle the rapidly evolving pathogens. Plants are known to synthesize an array of secondary metabolites referred as phytochemicals that have disease prevention properties. Potential efficacy and minimum to no side effects are the key advantages of plant-derived products, making them suitable choices for medical treatments. Hence, this review attempts to highlight and discuss the application of plant-derived compounds and extracts against ESKAPE Pathogens.

Device associated infections at a trauma surgical center of India: Trend over eight years

BACKGROUND

Device-associated infections (DAIs) are an important cause of excessive stay and mortality in ICUs. Trauma patients are predisposed to acquire such infections due to various factors. The prevalence of HAIs is underreported from developing nations due to a lack of systematic surveillance. This study reports the rates and outcomes of DAIs at a dedicated Trauma Center in trauma patients and compares the rates with a previous pilot observation.

METHODS

The study reports the finding of ongoing surveillance and the use of an indigenous software at a level-1 trauma center in India. Surveillance for ventilator-associated pneumonia, central line-associated bloodstream infections, and catheter-associated urinary tract infections was done based on standard definitions. The rates of HAIs and the profile of pathogens isolated from June 2010 to December 2018 were analyzed.

RESULTS

A total of 7485 patients were included in the analysis, amounting to 68,715 patient days. The rates of VAP, CLABSI, and CA-UTI were respectively 12, 9.8 1st 8.5/1000 device days. There was a significant correlation between device days and the propensity to develop infections. Of the 1449 isolates recovered from cases of DAIs, Acinetobacter sp (28.2%) was the most common isolate, followed by Candida sp. A high rate of multi-resistance was observed.

CONCLUSION

Automated surveillance was easy and useful for data entry and analysis. Surveillance data should be used for implementing preventive programs.

"Risk factors for ventilator-associated pneumonia following cardiac surgery: case-control study"

BACKGROUND

Ventilator-associated pneumonia (VAP) following cardiac surgery is a preventable complication associated with adverse outcomes.

AIMS

We aimed to assess risk factors and outcomes of VAP following cardiac surgery.

METHODS

A matched 1:3 case:control study, including adult patients undergoing cardiac surgery through sternotomy between Sep-2014 to Mar-2017 was conducted in a tertiary-care hospital in Israel. Cases included all patients developing VAP within 30 days after surgery, defined using consensus criteria. Controls were matched for age, gender and surgery type. Operative data were collected prospectively, other data were collected retrospectively. Cox regression was used for adjusted analysis of matched data.

FINDINGS

Out of 946 operated patients, we identified 57 patients with VAP after cardiac surgery (17.7 episodes per 1000 ventilator-days) matched to 149 controls. Significant independent risk factors for VAP included congestive heart failure (OR 2.357 95%CI 1.052-5.281), Chest re-exploration in ICU (OR 10.213 95%CI: 2.235-46.678), preoperative glucose levels (OR 1.1010 per 1 mg/dl increase 95%CI: 1.004-1.019) intraoperative red blood cell transfusions (OR 1.542 per 1 unit 95%CI: 1.109-2.094) and pulmonary hypertension (OR 2.261 95%CI 1.048-6.554). VAP was most commonly caused by Gram-negative pathogens. VAP was associated with higher mortality, longer length of stay, longer need for ventilator support and longer stay in ICU setting.

CONCLUSIONS

Postoperative VAP in cardiac surgery patients is associated with severe clinical outcomes. We identified risk factors that can aid in preventive measures implementation for high risk patients.