Prevalence of antibiotic-resistant organisms among hospitalized patients at a tertiary care center in Lebanon, 2010-2018

Antibacterial mechanism of Pseudomonas aeruginosa UKMP14T rhamnolipids against multidrug resistant Acinetobacter baumannii

Rhamnolipids, a major category of glycolipid biosurfactant, have recently gained enormous attention in medical field because of their relevance as effective antibacterial agents against a wide variety of pathogenic bacteria. Our previous studies have shown that rhamnolipids from an environmental isolate of Pseudomonas aeruginosa UKMP14T possess antibacterial, anti-adhesive and anti-biofilm activity against multidrug-resistant ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp.) pathogens. However, the mechanism of their antibacterial action remains unclear. Thus, this study aimed to elucidate the mechanism of the antibacterial action of P. aeruginosa UKMP14T rhamnolipids by studying the changes in cells of one of the ESKAPE pathogens, Acinetobacter baumannii, which is the most difficult strain to kill. Results revealed that rhamnolipid treatment rendered A. baumannii cells more hydrophobic as evaluated through contact angle measurements. It also induced the release of cellular proteins measuring 510 μg/mL at a rhamnolipid concentration of 1000 μg/mL. In addition, rhamnolipids were found to be bactericidal in their action as they could permeate the inner membranes, leading to a leak-out of nucleotides. More than 50 % of the cells were found to be killed upon 1000 μg/mL rhamnolipid treatment as observed through fluorescence microscopy. Other cellular changes such as irregular shape and size, membrane perturbations, clumping, shrinkage and physical damage were clearly visible in SEM, FESEM and laser micrographs. Furthermore, rhamnolipid treatment inhibited the levels of acyl-homoserine lactones (AHLs) in A. baumannii, which are vital for their biofilm formation and virulence. The obtained results indicate that P. aeruginosa UKMP14T rhamnolipids target outer and inner bacterial membranes through permeation, including physical damage to the cells, leading to cell leakage. Furthermore, AHL inhibition appears to be the mechanism behind their anti-biofilm action. All these observations can be correlated to rhamnolipids' antibacterial effect against A. baumannii.

Longitudinal genomic surveillance of multidrug-resistant Escherichia coli carriage in critical care patients

Colonization with multidrug-resistant Escherichia coli strains causes a substantial health burden in hospitalized patients. We performed a longitudinal genomics study to investigate the colonization of resistant E. coli strains in critically ill patients and to identify evolutionary changes and strain replacement events within patients. Patients were admitted to the intensive care unit and hematology wards at a major hospital in Lebanon. Perianal swabs were collected from participants on admission and during hospitalization, which were screened for extended-spectrum beta-lactamases and carbapenem-resistant Enterobacterales. We performed whole-genome sequencing and analysis on E. coli strains isolated from patients at multiple time points. The E. coli isolates were genetically diverse, with 11 sequence types (STs) identified among 22 isolates sequenced. Five patients were colonized by E. coli sequence type 131 (ST131)-encoding CTX-M-27, an emerging clone not previously observed in clinical samples from Lebanon. Among the eight patients whose resident E. coli strains were tracked over time, five harbored the same E. coli strain with relatively few mutations over the 5 to 10 days of hospitalization. The other three patients were colonized by different E. coli strains over time. Our study provides evidence of strain diversity within patients during their hospitalization. While strains varied in their antimicrobial resistance profiles, the number of resistance genes did not increase over time. We also show that ST131-encoding CTX-M-27, which appears to be emerging as a globally important multidrug-resistant E. coli strain, is also prevalent among critical care patients and deserves further monitoring.IMPORTANCEUnderstanding the evolution of bacteria over time in hospitalized patients is of utmost significance in the field of infectious diseases. While numerous studies have surveyed genetic diversity and resistance mechanisms in nosocomial infections, time series of within-patient dynamics are rare, and high-income countries are over-represented, leaving low- and middle-income countries understudied. Our study aims to bridge these research gaps by conducting a longitudinal survey of critically ill patients in Lebanon. This allowed us to track Escherichia coli evolution and strain replacements within individual patients over extended periods. Through whole-genome sequencing, we found extensive strain diversity, including the first evidence of the emerging E. coli sequence type 131 clone encoding the CTX-M-27 beta-lactamase in a clinical sample from Lebanon, as well as likely strain replacement events during hospitalization.

The experience of an antimicrobial stewardship program and antibiotic consumption and resistance trends during the COVID-19 pandemic at a tertiary care center in Beirut

BACKGROUND

Antimicrobial Resistance, a global concern, worsened with the COVID-19 pandemic that caused a surge of critically ill patients, increased antimicrobial consumption, and the spread of infections with multidrug-resistant organisms (MDROs). Antimicrobial Stewardship Programs (ASP) aim to optimize antimicrobial utilization to fight resistance. We aim to describe the ASP experience and to study antimicrobial consumption and MDRO rates among COVID-19 patients at a tertiary care center in Beirut.

METHODS

We compiled the ASP interventions, defined as ASP team recommendations, from January 2019 until December 2021. Data on antimicrobial consumption, expressed as a defined daily dose (DDD) per 100 patient days, was collected per quarter for all antimicrobials and restricted antimicrobials per ASP guidance. Our primary objective was to report on the ASP experience, and the secondary objective was to reflect on the rates of MDROs among hospitalized COVID-19 patients with respiratory or bloodstream bacterial co-infections between March 2020 and September 2021.

RESULTS

9922 ASP interventions were documented during this study period, with a noticeable correlation between COVID-19 surges in Lebanon and the number of ASP interventions. Acceptance rates for these recommendations improved over time, with a noticeable decrease in the proportion of interventions related to de-escalation and discontinuation of broad-spectrum antimicrobials. We noted an increase in all antimicrobial consumption after the onset of the pandemic, peaking in Q4 2020 (142.8 DDD of anti-infectives/100 patient days) and Q1 2021 (79.1 DDD of restricted anti-infectives/100 patient days). As expected, MDROs, particularly ESKAPE organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Carbapenem-resistant Enterobacteriaceae) accounted for 24% of isolates obtained from this cohort.

CONCLUSION

This study highlights the experience of the ASP as we adapted to the COVID-19 pandemic. The ASP team maintained its operations and continued to monitor antibiotic consumption and provide recommendations to limit antibiotic misuse in an effort to mitigate the impact of the pandemic on antimicrobial resistance.

Updates on the Status of Carbapenem-Resistant Enterobacterales in Lebanon

Carbapenem-resistant Enterobacterales (CRE) pathogens have been increasingly isolated and reported in Lebanon. Several studies have been published over the last two decades about the CRE situation in the country. However, compared to the worldwide data, those studies are scarce and mostly restricted to single center studies. In this review, we aim to present a comprehensive and reliable report illustrating the current situation regarding CRE in Lebanon. Variable studies have shown an increasing pattern of carbapenem resistance in Enterobacterales since the first reports of CRE isolates in 2007 and 2008. Escherichia coli and Klebsiella pneumoniae were the most detected ones. The OXA-48 class D carbapenemases were the most prevalent carbapenemases among CRE isolates. Moreover, the emergence of other carbapenemases like the NDM class B carbapenemase has been noticed. Strict infection control measures in hospitals, including the identification of CRE carriers, are needed in Lebanese hospitals since carriage is a potential risk for the spread of CRE in healthcare settings. The dissemination of CRE in the community is noticed and attributed to multiple causes, such as the refugee crisis, water contamination, and antimicrobial misuse. In conclusion, strict infection control measures in healthcare settings, in addition to accurate antimicrobial stewardship program implementation, are urgently needed.

Clinical predictors of mortality in patients with pseudomonas aeruginosa infection

BACKGROUND

Infections caused by Pseudomonas aeruginosa are difficult to treat with a significant cost and burden. In Lebanon, P. aeruginosa is one of the most common organisms in ventilator-associated pneumonia (VAP). P. aeruginosa has developed widespread resistance to multiple antimicrobial agents such as fluoroquinolones and carbapenems. We aimed at identifying risk factors associated for P. aeruginosa infections as well as identifying independent risk factors for developing septic shock and in-hospital mortality.

METHODS

We used a cross-sectional study design where we included patients with documented P. aeruginosa cultures who developed an infection after obtaining written consent. Two multivariable regression models were used to determine independent predictors of septic shock and mortality.

RESULTS

During the observed period of 30 months 196 patients were recruited. The most common predisposing factor was antibiotic use for more than 48 hours within 30 days (55%). The prevalence of multi-drug resistant (MDR) P. aeruginosa was 10%. The strongest predictors of mortality were steroid use (aOR = 3.4), respiratory failure (aOR = 7.3), identified respiratory cultures (aOR = 6.0), malignancy (aOR = 9.8), septic shock (aOR = 18.6), and hemodialysis (aOR = 30.9).

CONCLUSION

Understanding resistance patterns and risk factors associated with mortality is crucial to personalize treatment based on risk level and to decrease the emerging threat of antimicrobial resistance.

Methicillin- and Vancomycin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococci Isolated from Hospital Foods: Prevalence and Antimicrobial Resistance Patterns

This study aimed to investigate the prevalence of Methicillin- and Vancomycin-Resistant Staphylococcus aureus (MRSA, VRSA) and Vancomycin-Resistant Enterococcus (VRE) of hospital food samples in Mashhad, Iran. A total of 357 hospital food samples were collected from 13 hospitals. Enterococcus spp. and Staphylococcus aureus were identified using conventional cultural techniques following genotypic confirmation by PCR. The antibiotic resistance patterns of MRSA, VRSA, and VRE strains were analyzed using the disk diffusion methods. The prevalence of S. aureus and MRSA were 24.37% (87/357) and 22.98% (20.87), respectively. In addition, the vanB gene involved in vancomycin resistance was detected in 1.14% of the S. aureus strains. Enterococci and VRE had a prevalence of 15.4% (55/357) and 21.81% (12/55), respectively. Meat, chicken barbecues, and salad were the most commonly contaminated samples with S. aureus, MRSA, Enterococci, and VRE. PCR detected two vancomycin resistance genes, including vanA (1.81%, 1.55) and vanC2 (20%, 11.55) genes. MRSA strains revealed the highest resistance against penicillin, erythromycin, clindamycin, azithromycin, tetracycline, and gentamicin. The VRSA isolates were resistant to penicillin, ampicillin, oxacillin, cefoxitin, clindamycin, erythromycin, gentamicin, and trimethoprim-sulfamethoxazole. Furthermore, VRE isolates exhibited the highest resistance against quinupristin-dalfopristin, erythromycin, and tetracycline. The results of this study indicated that hospital foods might act as a reservoir of Enterococci spp. and S. aureus strains, which can transfer antibiotic resistance. Moreover, multidrug resistance (MDR) in some MRSA, VRSA, and VRE isolates represents a serious threat to susceptible persons in hospitals.

The Impact of Antimicrobial Stewardship and Infection Control Interventions on Acinetobacter baumannii Resistance Rates in the ICU of a Tertiary Care Center in Lebanon

Antimicrobial resistance is a serious threat to global health, causing increased mortality and morbidity especially among critically ill patients. This toll is expected to rise following the COVID-19 pandemic. Carbapenem-resistant Acinetobacter baumannii (CRAb) is among the Gram-negative pathogens leading antimicrobial resistance globally; it is listed as a critical priority pathogen by the WHO and is implicated in hospital-acquired infections and outbreaks, particularly in critically ill patients. Recent reports from Lebanon describe increasing rates of infection with CRAb, hence the need to develop concerted interventions to control its spread. We set to describe the impact of combining antimicrobial stewardship and infection control measures on resistance rates and colonization pressure of CRAb in the intensive care units of a tertiary care center in Lebanon before the COVID-19 pandemic. The antimicrobial stewardship program introduced a carbapenem-sparing initiative in April 2019. During the same period, infection control interventions involved focused screening, monitoring, and tracking of CRAb, as well as compliance with specific measures. From January 2018 to January 2020, we report a statistically significant decrease in carbapenem consumption and a decrease in resistance rates of isolated A. baumannii. The colonization pressure of CRAb also decreased significantly, reaching record low levels at the end of the intervention period. The results indicate that a multidisciplinary approach and combined interventions between the stewardship and infection control teams can lead to a sustained reduction in resistance rates and CRAb spread in ICUs.

Epidemiology, risk factors, and prediction score of carbapenem resistance among inpatients colonized or infected with 3rd generation cephalosporin resistant Enterobacterales

In this study, we determined the incidence and risk factors of Carbapenem-resistant Enterobacterales (CRE) acquisition in inpatients with 3rd generation cephalosporin-resistant (3GCR) Enterobacterales at a tertiary-care hospital in Lebanon, and suggested a risk prediction score for it. This is a retrospective matched case–control study of inpatients with 3GCR Enterobacterales that are carbapenem resistant (cases) versus those with carbapenem-sensitive isolates (controls). Data analysis was performed on IBM SPSS program, version 23.0 (Armonk, NY, USA: IBM Corp.). Categorical variables were compared between cases and controls through bivariate analysis and those with statistical significance (P < 0.05) were included in the forward stepwise multiple logistic regression analysis. To develop the CRE acquisition risk score, variables that maintained statistical significance in the multivariate model were assigned a point value corresponding to the odds ratio (OR) divided by the smallest OR identified in the regression model, and the resulting quotient was multiplied by two and rounded to the nearest whole number. Summation of the points generated by the calculated risk factors resulted in a quantitative score that was assigned to each patient in the database. Predictive performance was determined by assessing discrimination and calibration. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated for different cutoffs of the score. The incidence of CRE acquisition significantly increased with time from 0.21 cases/1000 patient-days (PD) in 2015 to 1.89 cases/1000PD in 2019 (r² = 0.789, P = 0.041). Multivariate analysis of matched data revealed that the history of cerebrovascular disease (OR 1.96; 95% CI 1.04–3.70; P = 0.039), hematopoietic cells transplantation (OR 7.75; 95% CI 1.52–39.36; P = 0.014), presence of a chronic wound (OR 3.38; 95% CI 1.73–6.50; P < 0.001), endoscopy done during the 3 months preceding the index hospitalization (OR 2.96; 95% CI 1.51–4.73; P = 0.01), nosocomial site of acquisition of the organism in question (OR 2.68; 95% CI 1.51–4.73; P = 0.001), and the prior use of meropenem within 3 months of CRE acquisition (OR 5.70; 95% CI 2.61–12.43; P < 0.001) were independent risk factors for CRE acquisition. A risk score ranging from 0 to 25 was developed based on these independent variables. At a cut-off of ≥ 5 points, the model exhibited a sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 64.5%, 85.8%, 82%, 70.7% and 75%, respectively. We also showed that only meropenem consumption intensity and CRE acquisition incidence density showed a strong positive correlation(r = 0.798, P = 0.106), unlike imipenem (r = − 0.868, P = 0.056) and ertapenem (r = 0.385, P = 0.522). Patients with a score of ≥ 5 points in our model were likely to acquire CRE. Only meropenem was associated with CRE carriage. Our proposed risk prediction score would help target surveillance screening for CRE amongst inpatients at the time of hospital admission and properly guide clinicians on using anti-CRE therapy.

Valorization of Winemaking By-Products as a Novel Source of Antibacterial Properties: New Strategies to Fight Antibiotic Resistance

The emergence of antibiotic-resistance in bacteria has limited the ability to treat bacterial infections, besides increasing their morbidity and mortality at the global scale. The need for alternative solutions to deal with this problem is urgent and has brought about a renewed interest in natural products as sources of potential antimicrobials. The wine industry is responsible for the production of vast amounts of waste and by-products, with associated environmental problems. These residues are rich in bioactive secondary metabolites, especially phenolic compounds. Some phenolics are bacteriostatic/bactericidal against several pathogenic bacteria and may have a synergistic action towards antibiotics, mitigating or reverting bacterial resistance to these drugs. Complex phenolic mixtures, such as those present in winemaking residues (pomace, skins, stalks, leaves, and especially seeds), are even more effective as antimicrobials and could be used in combined therapy, thereby contributing to management of the antibiotic resistance crisis. This review focuses on the potentialities of winemaking by-products, their extracts, and constituents as chemotherapeutic antibacterial agents.