Correlation between antibiotic consumption and resistance of Pseudomonas aeruginosa in a teaching hospital implementing an antimicrobial stewardship program: A longitudinal observational study

Antimicrobial Activity of a Synthetic Brevibacillin Analog Against Multidrug-Resistant Campylobacter spp

Campylobacter spp. is one of the most prevalent causes of zoonotic foodborne infections associated with diarrhea in humans. The growing threat of antibiotic resistance calls for innovative approaches. The antimicrobial lipopeptide brevibacillin produced by Brevibacillus laterosporus and its synthetic analog brevibacillin Thr1 showed promising activity against Salmonella and E. coli. The latter is a 1602.13 Da positively charged (+3) synthetic peptide of 13 residues that showed reduced cytotoxicity (IC50 of 32.2 µg/mL against Caco-2 cells) and hemolytic activity (1.2% hemolysis at 128 µg/mL) compared to the native peptide. It contains an N-terminal L-isoleucic fatty acid chain and four non-proteinogenic amino acids and ends with valinol at its C-terminus. One key structural modification is the substitution of α,β-dehydrobutyric acid with threonine. We investigated the antimicrobial potential of the synthetic brevibacillin Thr1 analog against a collection of 44 clinical Campylobacter spp. that were obtained from two reference laboratories. Susceptibility testing revealed marked resistance to ciprofloxacin, tetracycline, and ampicillin among the strains, with more than half expressing a multidrug-resistant phenotype. The genomes of the 44 strains were sequenced to study the genes responsible for their antimicrobial resistance. Tetracycline resistance was associated with tet(O), ciprofloxacin resistance with mutations in gyrA and regulatory sequences modulating the expression of an efflux system, and aminoglycoside resistance with genes of the aph family. The brevibacillin Thr1 analog was produced by chemical synthesis, and evaluation of its activity against a subset of clinical strains by microdilution revealed minimum inhibitory concentration and minimum bactericidal concentration ranging from 8 µg/mL to 64 µg/mL. The peptide was active against multidrug-resistant isolates with a bactericidal effect. Of note, despite numerous attempts, it proved impossible to select Campylobacter spp. for resistance to the brevibacillin Thr1 analog. These results underline the potential of lipopeptides, notably brevibacillin, as antimicrobial alternatives against antibiotic-resistant Campylobacter bacterial infections.

Single-center observational analysis of a pharmacist-driven antibiotic time-out targeting antipseudomonal drugs

This study found that implementation of a pharmacist-driven antipseudomonal antibiotic time-out at a 450-bed community hospital led to a 5% reduction in the use of targeted antipseudomonal antibiotics (P = .12), which may be clinically meaningful as it extrapolates to approximately 1,800 avoided days of therapy annually.

Molecular Analysis of Pseudomonas aeruginosa Isolates with Mutant gyrA Gene and Development of a New Ciprofloxacin Derivative for Antimicrobial Therapy

This study focuses on the prevalence of Pseudomonas aeruginosa in various medical specimens. In addition, the investigates of this research shows the genetic analysis of pathogen-resistant isolates and chemical modifications to ciprofloxacin. A total of 225 specimens from men and women aged 30 to 60 were carefully collected and examined, including samples from wound, burn, urine, sputum, and ear samples. The data were obtained from AL Muthanna hospitals. PCR-RFLP and gene expression analysis were used to identify resistant strains and explore the genetic basis of antibiotic resistance. A ciprofloxacin derivative was synthesized and confirmed through FT-IR, 1H-NMR, and mass spectroscopy techniques then it was tested as antibacterial agent. Also, molecular docking study was conducted to predict the mechanism of action for the synthesized derivative. The results demonstrated that wound samples had the highest positive rate (33.7%) of P. aeruginosa isolates. The PCR-RFLP testing correlated ciprofloxacin resistance with gyrA gene mutation. Gene expression analysis revealed significant changes in the gyrA gene expression in comparison to the reference rpsL gene subsequent to exposure to the synthesized derivative. Furthermore, the molecular docking investigation illustrated the strategic positioning of the ciprofloxacin derivative within the DNA-binding site of the gyrA enzyme. The examination of genetic expression patterns manifested diverse effects attributed to the CIP derivative on P. aeruginosa, thus portraying it as a viable candidate in the quest for the development of novel antimicrobial agents. Ciprofloxacin derivative may offer new antimicrobial therapeutic options for treating Pseudomonas aeruginosa infections in wound specimens, addressing resistance and gyrA gene mutations.

Correlation between carbapenem susceptibility in Pseudomonas aeruginosa and modified antibiotic heterogeneity index: a multicenter observational study using a surveillance platform

Objective

This study focused on exploring the relationship between antimicrobial use indicators, including the modified antibiotic heterogeneity index (mAHI), and the carbapenem susceptibility in Pseudomonas aeruginosa.

Design

Survey-based observational study conducted across multiple facilities.

Setting

Public community hospital institutions.

Methods

This survey was conducted in 15 community hospitals in Japan. Indicators, such as the defined daily doses (DDDs), days of therapy (DOTs), antibiotic heterogeneity index (AHI), and mAHI, were analyzed for P. aeruginosa carbapenem susceptibility using Spearman's rank correlation. The predictive accuracies of the AHI and mAHI for carbapenem susceptibility were compared using DeLong's test for the 2 correlated receiver operating characteristic curves.

Results

No significant correlations were observed between DDDs or DOTs and carbapenem susceptibility. However, a significant correlation was observed between carbapenem susceptibility and the mAHI (r = 0.261, P = .02), which also demonstrated a higher predictive accuracy for high susceptibility rates than that of the AHI (area under the curve: 0.75 vs 0.58, p < .01). The optimal mAHI cutoff value for predicting 90% susceptibility was 0.765, with a sensitivity of 67.7% and specificity of 76.5%.

Conclusions

The mAHI may be a better predictor of carbapenem susceptibility than other commonly used indicators. This study underscores the utility of the mAHI as an effective indicator of antimicrobial usage patterns for managing carbapenem susceptibility in P. aeruginosa. Incorporating the mAHI into antimicrobial stewardship programs could enhance the effectiveness of antimicrobial interventions across diverse healthcare settings.

Bacterial profile, and independent predictors for healthcare-associated pneumonia persistently caused by multidrug-resistant Gram-negative bacteria for patients with the preceding multidrug-resistant Gram-negative pneumonia in Taiwan

OBJECTIVES

To understand the microbial profile and investigate the independent predictors for healthcare-associated pneumonia (HCAP) pertinaciously caused by isolates of multidrug-resistant (MDR) Gram-negative bacteria (GNB).

METHODS

Multicenter ICU patients who received appropriate antibiotic treatments for preceding pneumonia due to MDR GNB isolates and subsequently developed HCAP caused by either MDR GNB (n = 126) or non-MDR GNB (n = 40) isolates in Taiwan between 2018 and 2023 were enrolled. Between the groups of patients with HCAP due to MDR GNB and non-MDR GNB, the proportions of the following variables, including demographic characteristics, important co-morbidities, nursing home residence, physiological severity, intervals between two hospitalizations, steroid use, the tracheostomy tube use alone, ventilator support, and the predominant GNB species involving HCAP, were analyzed using the chi-square test. Logistic regression was employed to explore the independent predictors for HCAP persistently caused by MDR GNB in the aforementioned variables with a P-value of <0.15 in the univariate analysis.

RESULTS

MDR-Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii complex were the three predominant species causing HCAP. Chronic structural lung disorders, diabetes mellitus, intervals of ≤30 days between two hospitalizations, use of the tracheostomy tube alone, and prior pneumonia caused by MDR A. baumannii complex were shown to independently predict the HCAP tenaciously caused by MDR GNB. Conversely, the preceding pneumonia caused by MDR P. aeruginosa was a negative predictor.

CONCLUSION

Identifying predictors for HCAP persistently caused by MDR GNB is crucial for prescribing appropriate antibiotics.

Mechanisms of action of berberine hydrochloride in planktonic cells and biofilms of Pseudomonas aeruginosa

The increasing prevalence of extensively drug-and pan-drug-resistant Pseudomonas aeruginosa is a major concern for global public health. Therefore, it is crucial to develop novel antimicrobials that specifically target P. aeruginosa and its biofilms. In the present study, we determined that berberine hydrochloride inhibited the growth of planktonic bacteria as well as prevented the formation of biofilms. Moreover, we observed downregulation in the expression of pslA and pelA biofilm-related genes. Compared with existing antibiotics, berberine hydrochloride exhibits multiple modes of action against P. aeruginosa. Our findings suggest that berberine hydrochloride exerts its antimicrobial effects by damaging bacterial cell membranes, generating reactive oxygen species (ROS), and reducing intracellular adenosine triphosphate (ATP) levels. Furthermore, berberine hydrochloride showed minimal cytotoxicity and reduced susceptibility to drug resistance. In a mouse model of peritonitis, it significantly inhibited the growth of P. aeruginosa and exhibited a strong bacteriostatic action. In conclusion, berberine hydrochloride is a safe and effective antibacterial agent that inhibits the growth of P. aeruginosa.

Relationship between Antibiotic Consumption and Resistance: A Systematic Review

Background

Unreserved use of antibiotics exerted selective pressure on susceptible bacteria, resulting in the survival of resistant strains. Despite this, the relationship between antibiotic resistance (ABR) and antibiotic consumption (ABC) is rarely studied. This systematic review aims to review the relationship between ABC and ABR from 2016 to 2022.

Methods

Articles published over 7 years (2016-2022) were searched from December 23 to 31, 2022. The search strategy was developed by using keywords for ABC and ABR. From 3367 articles, 58 eligible articles were included in the final review.

Results

The pooled ABC was 948017.9 DPDs and 4108.6 DIDs where over 70% of antibiotics were from the Watch and Reserve category based on the WHO AWaRe classification. The average pooled prevalence of ABR was 38.4%. Enterococcus faecium (59.4%), A. baumannii (52.6%), and P. aeruginosa (48.6%) were the most common antibiotic-resistant bacteria. Cephalosporins (76.8%), penicillin (58.3%), and aminoglycosides (52%) were commonly involved antibiotics in ABR. The positive correlation between ABR and consumption accounted for 311 (81%). The correlation between ABR P. aeruginosa and ABC accounted for 87 (22.7%), followed by 78 (20.3%) and 77 (20.1%) for ABR E. coli and K. pneumoniae with ABCs, respectively. Consumption of carbapenems and fluoroquinolones was most commonly correlated with resistance rates of P. aeruginosa, K. pneumoniae, E. coli, and A. baumannii.

Conclusion

There is a positive correlation between ABC and the rate of ABR. The review also revealed a cross-resistance between the consumption of different antibiotics and ABR. Optimizing antibiotic therapy and reducing unnecessary ABC will prevent the emergence and spread of ABR. Thus, advocating the implementation of stewardship programs plays a pivotal role in containing ABR.

Novel Fluoroquinolones with Possible Antibacterial Activity in Gram-Negative Resistant Pathogens: In Silico Drug Discovery

Antibiotic resistance is a global threat to public health, and the search for new antibacterial therapies is a current research priority. The aim of this in silico study was to test nine new fluoroquinolones previously designed with potential leishmanicidal activity against Campylobacter jejuni, Escherichia coli, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Salmonella typhi, all of which are considered by the World Health Organization to resistant pathogens of global concern, through molecular docking and molecular dynamics (MD) simulations using wild-type (WT) and mutant-type (MT) DNA gyrases as biological targets. Our results showed that compound 9FQ had the best binding energy with the active site of E. coli in both molecular docking and molecular dynamics simulations. Compound 9FQ interacted with residues of quinolone resistance-determining region (QRDR) in GyrA and GyrB chains, which are important to enzyme activity and through which it could block DNA replication. In addition to compound 9FQ, compound 1FQ also showed a good affinity for DNA gyrase. Thus, these newly designed molecules could have antibacterial activity against Gram-negative microorganisms. These findings represent a promising starting point for further investigation through in vitro assays, which can validate the hypothesis and potentially facilitate the development of novel antibiotic drugs.

Carbapenem-Resistant Pseudomonas aeruginosa Bacteremia, through a Six-Year Infection Control Program in a Hospital

BACKGROUND

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a life-threatening healthcare-associated infection affecting especially patients with immunosuppression and comorbidities. We investigated the association between the incidence of CRPA bacteremia, antibiotic consumption, and infection control measures in a hospital during 2013-2018.

METHODS

We prospectively recorded the incidence of CRPA bacteremia, antibiotic consumption, use of hand-hygiene solutions, and isolation rates of multidrug-resistant (MDR) carrier patients.

FINDINGS

The consumption of colistin, aminoglycosides, and third-generation cephalosporins decreased significantly in the total hospital and its divisions (p-value < 0.001 for all comparisons) while the consumption of carbapenems decreased significantly in the adults ICU (p-value = 0.025). In addition, the incidence of CRPA significantly decreased in the total hospital clinics and departments (p-values = 0.027 and 0.042, respectively) and in adults clinics and departments (p-values = 0.031 and 0.051, respectively), while in the adults ICU, the incidence remained unchanged. Increased isolation rates of MDR carrier patients, even two months before, significantly correlated with decreased incidence of CRPA bacteremia (IRR: 0.20, 95% CI: 0.05-0.73, p-value = 0.015) in the adults ICU. Interestingly, when the use of hand-hygiene solutions (alcohol and/or scrub) increased, the consumption of advanced, nonadvanced, and all antibiotics decreased significantly.

CONCLUSION

In our hospital, multimodal infection control interventions resulted in a significant reduction of CRPA bacteremia, mostly due to the reduction of all classes of antibiotics.

The Effect of Decreased Antipseudomonal Drug Consumption on Pseudomonas aeruginosa Incidence and Antimicrobial Susceptibility Profiles over 9 Years in a Lebanese Tertiary Care Center

Pseudomonas aeruginosa (PAE) is intrinsically resistant to numerous classes of antimicrobials such as tetracycline and β-lactam antibiotics. More epidemiological surveillance studies on the antimicrobial susceptibility profiles of PAE are needed to generate clinically significant data and better guided therapeutic options. We describe and analyze in a retrospective study the epidemiologic trends of 1827 Pseudomonas spp. isolates (83.5% PAE, 16.4% Pseudomonas sp., and 0.2% Pseudomonas putida) from various clinical specimens with their resistance patterns to antimicrobial consumption at a tertiary medical center in Lebanon between January 2010 and December 2018. We report a significant drop in the incidence of PAE from sputum (p-value = 0.05), whereas bloodstream infection isolation density showed no trend over the study period. We also registered a minimal but statistically significant drop in resistance of Pseudomonas to certain antibiotics and a decrease in the consumption of antipseudomonal antibiotics (p-value < 0.001). Only 61 PAE isolates from a total of 1827 Pseudomonas cultures (3.33%) were difficult to treat, of which only one was a bacteremia. Interestingly, we found that the carbapenem susceptibility of Pseudomonas was unaffected by the decrease in their consumption. These results augur that antimicrobial pressure may not be the sole contributor to resistance emergence. Finally, antimicrobial stewardship seems to have a positive impact on nosocomial epidemiology.