Multidrug Resistant Pseudomonas aeruginosa in Iran: A Systematic Review and Metaanalysis

Curcumin-mediated photodynamic disinfection strategy with specific spectral range for mucoid Pseudomonas Aeruginosa from hospital water

BACKGROUND

Hospital water systems represent critical environments for the transmission of pathogens, including multidrug-resistant strains like mucoid Pseudomonas aeruginosa (M-PA). Conventional disinfection methods often struggle to eradicate these pathogens effectively, highlighting the need for innovative approaches.

OBJECTIVE

This study aimed to develop an enhanced photodynamic disinfection strategy targeting M-PA from hospital water systems, using curcumin-mediated photodynamic inactivation (PDI) with specific spectral range.

METHODS

An M-PA strain isolated from hospital water was subjected to photodynamic treatment using curcumin as the photosensitizer. The efficacy of different wavelengths of light and varying concentrations of curcumin, with and without Tris-EDTA adjuvants, was evaluated through bacterial enumeration, ROS level measurements, transcriptome analysis, and assessment of virulence factors and biofilm formation. In vivo experiments utilizing a DSS-induced colitis mouse model assessed the protective effects of the photodynamic treatment against M-PA infection.

RESULTS

Our findings demonstrated that the combination of curcumin-mediated PDI with specific spectral range effectively reduced M-PA counts in water, particularly when supplemented with Tris-EDTA. Transcriptome analysis revealed significant downregulation of virulence-related genes under sublethal photodynamic conditions. Furthermore, photodynamic treatment inhibited pyocyanin production and biofilm formation in M-PA, highlighting its potential to disrupt pathogenicity mechanisms. In vivo experiments showed that PDI attenuated M-PA-induced colitis in mice, indicating its protective efficacy.

CONCLUSION

This study presents a promising photodynamic disinfection strategy for combating M-PA from hospital water. By optimizing curcumin-mediated PDI with specific spectral range and adjuvants, our approach demonstrates substantial efficacy in reducing bacterial counts, inhibiting virulence factors, and preventing M-PA-associated colitis.

Phenotypic and genotypic identification of class C and D β-lactamases in clinical isolates of Pseudomonas aeruginosa: a cross-sectional study

Background and Aims

The emergence of Pseudomonas aeruginosa (P. aeruginosa) antibiotic resistance is an important public health problem worldwide that can negatively affect infection control. Therefore, obtaining knowledge about antibiotic resistance mechanisms is necessary for infection control policies. This study aimed to determine the frequency of class C and D β-lactamases in P. aeruginosa strains isolated from patients referred to Ardabil hospitals using phenotypic and genotypic tests.

Methods

Phenotypic detection of β-lactamases including AmpC cephalosporinase, oxacillinase (OXA)-type extended-spectrum β-lactamases (ESBLs), and OXA-type carbapenemases were performed using the disk diffusion-based methods. Amplification of genes encoding classes C (ampC and FOX genes) and D (OXA-1, OXA-2, OXA-10, OXA-23, and OXA-48 genes) β-lactamases was performed using the polymerase chain reaction (PCR) method. A quantitative reverse transcription PCR (qRT-PCR) method was used to determine the expression level of the ampC gene among multiple drug-resistant and imipenem-resistant P. aeruginosa strains.

Results

In phenotypic tests, the prevalence of AmpC cephalosporinase, OXA-type ESBLs, and OXA-type carbapenemases were 52.5%, 7.2%, and 95.8%, respectively. In genotypic tests, the prevalence of ampC, FOX, OXA-1, OXA-2, OXA-10, OXA-23, and OXA-48 genes were 100%, 0%, 4.3%, 60.8%, 42%, 29.7%, and 2.9%, respectively. In addition, the ampC gene overexpression was seen in 16 (33.3%) drug-resistant P. aeruginosa clinical isolates.

Conclusion

Given the presence of class C and D β-lactamases in clinical isolates of P. aeruginosa in Ardabil hospitals, early detection of these strains can help prevent the spread of resistant strains in hospital environments and subsequent treatment failure.

Antimicrobial resistance profile of Pseudomonas aeruginosa clinical isolates from healthcare-associated infections in Ethiopia: A systematic review and meta-analysis

BACKGROUND

Antimicrobial-resistant (AMR) bacterial infection is a significant global threat to the healthcare systems. Pseudomonas aeruginosa, the leading infectious agent in the healthcare setting is now one of the major threats due to AMR. A comprehensive understanding of the magnitude of AMR, particularly highly public health important pathogens such as P. aeruginosa, is necessary for the management of infections based on local information.

OBJECTIVE

This systematic review and meta-analysis aimed to determine the country-wide AMR of P. aeruginosa.

METHODS

Systematic searches were performed to retrieve articles from PubMed, Scopus, Web of Science, ScienceDirect electronic databases, Google Scholar search engine, and repository registrars from 2015 to 31st December 2023. Twenty-three studies that provided important data on AMR in P. aeruginosa were systematically reviewed and analyzed to determine the country-wide magnitude of P. aeruginosa AMR profile from healthcare-associated infections. AMR of P. aeruginosa to 10 different antibiotics were extracted separately into Microsoft Excel and analyzed using STATA 17.0. Cohen's kappa was computed to determine the agreement between reviewers, the Inverse of variance (I2) was used to evaluate heterogeneity across studies, and Egger's test to identify publication bias. A random effect model was used to determine the pooled resistance to each antibiotic. Subgroup analysis was performed by infection type and year of publication.

RESULTS

This systematic review and meta-analysis revealed that the pooled prevalence of P. aeruginosa in clinical specimens associated with HAI was 4.38%(95%CI: 3.00-5.76). The pooled prevalence of AMR in P. aeruginosa for different antibiotics varies, ranging from 20.9% (95%CI: 6.2-35.8) for amikacin to 98.72% (95%CI: 96.39-101.4) for ceftriaxone. The pooled resistance was higher for ceftriaxone (98.72%), Trimethoprim-sulfamethoxazole (75.41), and amoxicillin-clavulanic acid (91.2). In contrast relatively lower AMR were observed for amikacin (20.9%) and meropenem (28.64%). The pooled multi-drug resistance (MDR) in P. aeruginosa was 80.5% (95%CI: 66.25-93.84). Upon subgroup analysis by infection types and year of publication, P. aeruginosa isolated from healthcare-associated infections exhibited higher resistance to ceftazidime (94.72%) compared to isolates from mixed types of healthcare-associated infections (70.84%) and surgical site infections (57.84%). Antimicrobial resistance in gentamicin was higher during the periods of 2018-2020 (73.96%), while comparatively lower during 2021-2023 (42.69%) and 2015-2017 (29.82%).

CONCLUSIONS

Significantly high AMR and MDR were observed from this systematic review and meta-analysis. AMR obtained from this systematic review and meta-analysis urges the need for improved infection control, antimicrobial stewardship practices, and strengthened surveillance systems to control the spread of AMR and ensure effective treatment of P. aeruginosa infections.

PROTOCOL REGISTRATION

This systematic review and meta-analysis was registered on PROSPERO (Registration ID: CRD42024518145).

Prevalence and mechanisms of aminoglycoside resistance among drug-resistant Pseudomonas aeruginosa clinical isolates in Iran

BACKGROUND

Aminoglycosides have been a cornerstone of the treatment of nosocomial infections caused by Pseudomonas aeruginosa for over 80 years. However, escalating emergence of resistance poses a significant challenge. Therefore, this study aimed to investigate the prevailing patterns of aminoglycoside resistance among clinical isolates of P. aeruginosa in Iran; as well as the underlying resistance mechanisms observed in patients referred to Ardabil hospitals.

METHODS

A total of 200 isolates from five hospitals were evaluated. The resistance profiles of P. aeruginosa isolates to tobramycin, amikacin, and netilmicin were determined using the disk diffusion method. The capacity of aminoglycoside-resistant isolates to form biofilms was assessed through a phenotypic assay, and the results were confirmed using the gene amplification technique. The presence of genes associated with aminoglycoside resistance was detected using polymerase chain reaction (PCR). Quantitative reverse transcription PCR (qRT-PCR) was performed to measure the expression levels of genes encoding the MexXY-OprM efflux pump and PhoPQ two-component system (TCS).

RESULTS

The prevalence of aminoglycoside-resistant P. aeruginosa isolates was 48%, with 94.7% demonstrating multidrug resistance (MDR). All aminoglycoside-resistant P. aeruginosa strains exhibited biofilm-forming capabilities and harbored all the genes associated with biofilm production. Among the nine genes encoding 16S rRNA methylase and aminoglycoside-modifying enzymes, three genes were detected in these isolates: aac(6')-Ib (85.4%), ant(2'')-Ia (18.7%), and aph(3')-VI (3.1%). Additionally, all aminoglycoside-resistant P. aeruginosa isolates carried mexY and phoP genes, although the expression levels of mexY and phoP were 75% and 87.5%, respectively.

CONCLUSION

Given the considerably high prevalence of aminoglycoside-resistant P. aeruginosa strains, urgent measures are warranted to transition towards the use of novel aminoglycosides and to uphold vigilant surveillance of resistance patterns.

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.

Global antimicrobial resistance and use surveillance system (GLASS 2022): Investigating the relationship between antimicrobial resistance and antimicrobial consumption data across the participating countries

For the first time since 2015, the World Health Organization's (WHO) global Antimicrobial Resistance and Use Surveillance (GLASS) featured both global reports for antimicrobial resistance (AMR) and antimicrobial consumption (AMC) data in its annual reports. In this study we investigated the relationship of AMR with AMC within participating countries reported in the GLASS 2022 report. Our analysis found a statistically significant correlation between beta-lactam/cephalosporin and fluoroquinolones consumption and AMR to these antimicrobials associated with bloodstream E. coli and Klebsiella pneumoniae among the participating countries (P<0.05). We observed that for every 1 unit increase in defined daily dose DDD of beta-lactam/cephalosporins and quinolone consumptions among the countries, increased the recoveries of bloodstream-associated beta-lactam/cephalosporins-resistant E. coli/Klebsiella spp. by 11-22% and quinolone-resistant E. coli/Klebsiella spp. by 31-40%. When we compared the antimicrobial consumptions between the antimicrobial ATC (Alphanumeric codes developed by WHO) groups and countries, we observed a statistically significant higher daily consumption of beta-lactam-penicillins (J01C, DDD difference range: 5.23-8.13) and cephalosporins (J01D, DDD difference range: 2.57-5.13) compared to other antimicrobial groups among the countries (adjusted for multiple comparisons using Tukey's method). Between the participating countries, we observed a statistically significant higher daily consumption of antimicrobial groups in Iran (DDD difference range: 3.63-4.84) and Uganda (DDD difference range: 3.79-5.01) compared to other participating countries (adjusted for multiple comparisons using Tukey's method). Understanding AMC and how it relates to AMR at the global scale is critical in the global AMR policy development and implementation of global antimicrobial stewardship.

The global epidemiology of ventilator-associated pneumonia caused by multi-drug resistant Pseudomonas aeruginosa: A systematic review and meta-analysis

OBJECTIVES

The objective of this systematic review and meta-analysis was to estimate the global prevalence of multi-drug resistant (MDR) Pseudomonas aeruginosa causing ventilator-associated pneumonia (VAP).

METHODS

The systematic search was conducted in four databases. Original studies describing MDR P. aeruginosa VAP prevalence in adults from 2012- 2022 were included. A meta-analysis, using the random effects model, was conducted for overall, subgroups (country, published year, study duration, and study design), and European data, respectively. Univariate meta-regression based on pooled estimates was also conducted. Systematic review registered in International Prospective Register of Systematic Review (CRD42022384035).

RESULTS

In total of 31 studies, containing a total of 7951 cases from 16 countries, were included. The overall pooled prevalence of MDR among P. aeruginosa causing VAP was 33% (95% confidence interval [CI] 27.7-38.3%). The highest prevalence was for Iran at 87.5% (95% CI 69-95.7%), and the lowest was for the USA at 19.7% (95% CI 18.6-20.7%). The European prevalence was 29.9% (95% CI 23.2-36.7%).

CONCLUSIONS

This review indicates that the prevalence of MDR P. aeruginosa in patients with VAP is generally high and varies significantly between countries; however, data are insufficient for many countries. The data in this study can provide a reference for VAP management and drug customisation strategies.

Impact of Solidago virgaurea Extract on Biofilm Formation for ESBL-Pseudomonas aeruginosa: An In Vitro Model Study

The increasing disparity between antimicrobial resistance (AMR) and the development of new antimicrobials continues to pose a significant global health concern. However, plant extracts have shown promise in combating this issue either through their inherent antimicrobial activity or by serving as potential reservoirs of effective antimicrobial compounds. These compounds have the ability to target pathogenic biofilms and inhibit the production of extended-spectrum β -lactamases (ESBLs). However, there is limited research available on the antibacterial properties of goldenrod extract. Thus, the objective of this study was to investigate the impact of S. virgaurea (SV) extract on the viability and ability to form biofilms of ESBL-Pseudomonas aeruginosa (P. aeruginosa). A cross-sectional study was conducted from August 2022 to March 2023. The broth microdilution method was employed to determine the minimum inhibitory concentration (MIC) of the (SV) extract. Subsequently, the minimum bactericidal concentration (MBC) was determined based on the MIC values obtained. The antibiotic susceptibility of bacteria was evaluated using the Kirby disk diffusion assay and an Antimicrobial Susceptibility Testing (AST) card in conjunction with the Vitek-2 compact system. Biofilm formation was evaluated using Congo red and a 96-well Elisa plate, while the presence of extended-spectrum β-lactamases (ESBLs) was estimated by measuring the reduction of nitrocefin at a wavelength of 390 nm. In addition, treatment of biofilm and ESBL activity with SV extract using 96-well Elisa plate and nitrocefin hydrolyzing, respectively. The resistance rates of P. aeruginosa isolates to the tested antibiotics were as follows: Levofloxacin 33%, Ciprofloxacin 40%, Amikacin 49%, Meropenem 50%, Cefepime 70%, Ceftazidime 75%, Cefotaxime 85%, Piperacillin-Tazobactam 90%, Amoxiclav 97%, Ampicillin 99%, Ceftriaxone 100%. The prevalence of MDR-P. aeruginosa, XDR-P. aeruginosa, PDR-P. aeruginosa and non-MDR-PA were 40% (n = 40), 7% (n = 7), 3% (n = 3) and 50% (n = 50), respectively. From the GC-MS results, it was observed that the presence of Octadecane, Clioquinol, Glycerol tricaprylate, hexadecanoic acid, cis-13-octadecenoic acid, oleic acid and Propanamide were the major components in the Solidago extract. In the determination of plant crude extracts, the values ranged between 0.25 and 64 mg/mL against bacteria. The resulting activity of the extract showed a significant statistical relationship at a p-value ≤ 0.01 against ESBL production and biofilm formation in P. aeruginosa. The S. virgaurea extract exhibited effectiveness in inhibiting biofilm formation and combating P. aeruginosa strains that produce extended-spectrum β-lactamases (ESBLs).

The Prevalence of Metallo-Beta-Lactamese-(MβL)-Producing Pseudomonas aeruginosa Isolates in Brazil: A Systematic Review and Meta-Analysis

The purpose of the current study is to describe the prevalence of Pseudomonas aeruginosa (PA)-producing MβL among Brazilian isolates and the frequency of blaSPM-1 in MβL-PA-producing isolates. From January 2009 to August 2023, we carried out an investigation on this subject in the internet databases SciELO, PubMed, Science Direct, and LILACS. A total of 20 papers that met the eligibility requirements were chosen by comprehensive meta-analysis software v2.2 for data retrieval and analysis by one meta-analysis using a fixed-effects model for the two investigations. The prevalence of MβL-producing P. aeruginosa was 35.8% or 0.358 (95% CI = 0.324-0.393). The studies' differences were significantly different from one another (x2 = 243.15; p < 0.001; I2 = 92.18%), so they were divided into subgroups based on Brazilian regions. There was indication of asymmetry in the meta-analyses' publishing bias funnel plot; so, a meta-regression was conducted by the study's publication year. According to the findings of Begg's test, no discernible publishing bias was found. blaSPM-1 prevalence was estimated at 66.9% or 0.669 in MβL-PA isolates (95% CI = 0.593-0.738). The analysis of this one showed an average heterogeneity (x2 = 90.93; p < 0.001; I2 = 80.20%). According to the results of Begg's test and a funnel plot, no discernible publishing bias was found. The research showed that MβL-P. aeruginosa and SPM-1 isolates were relatively common among individuals in Brazil. P. aeruginosa and other opportunistic bacteria are spreading quickly and causing severe infections, so efforts are needed to pinpoint risk factors, reservoirs, transmission pathways, and the origin of infection.

Epidemiology, Evolution of Antimicrobial Profile and Genomic Fingerprints of Pseudomonas aeruginosa before and during COVID-19: Transition from Resistance to Susceptibility

BACKGROUND

The purpose of the study was to describe the epidemiological implication of Pseudomonas aeruginosa between 2017-2022 in a tertiary hospital from Romania, including the molecular fingerprinting of similar phenotypic strains (multidrug-resistant isolates), which would have an important health impact. The study also describes the resistance profile of P. aeruginosa before and during COVID-19, which might bring new information regarding the management of antibiotic treatments.

MATERIALS AND METHODS

Information regarding wards, specimen types, species, and antibiotic resistance profile of 1994 strains of Pseudomonas spp. Isolated over a period of 6 years in Mures Clinical County Hospital, Romania, was collected from the WHONET database. From 50 multidrug-resistant isolates, molecular fingerprinting was performed by Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) to prove the potential clonal distribution.

RESULTS

A number of 1994 Pseudomonas spp. were isolated between 2017-2022, from which P. aeruginosa was the most frequent species, 97.39% (n = 1942). P. aeruginosa was most frequently isolated in 2017 (n = 538), with the dermatology department as the main source, mainly from pus secretion. A drop in the harvesting rate was noted in 2020 due to COVID-19 restrictions. Regarding the resistance profile, there are a few modifications. The susceptibility of P. aeruginosa to carbapenems, piperacillin-tazobactam, and amikacin suffered alterations before and during COVID-19. The molecular fingerprinting showed three P. aeruginosa clusters, including strains with 80-99% similarity.

Antibiotic therapy for pan-drug-resistant infections

Antibiotic resistance occurs when microorganisms resist the drugs used against the infection caused by them and neutralize their effects over time using various mechanisms. These mechanisms include preventing drug absorption, changing drug targets, drug inactivating, and using efflux pumps, which ultimately cause drug resistance, which is named pan-drug-resistant (PDR) infection if it is resistant to all antimicrobial agents. This type of drug resistance causes many problems in society and faces the health system with difficulties; therefore their treatment is crucial and encourages doctors to develop new drugs to treat them. PDR Gram-negative bacteria, including Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli are among the most significant resistant bacteria to many antimicrobial agents, and only a limited range of antibiotics, especially synergistically are effective on them. For the therapy of PDR A. baumannii, tigecycline in combination with colestimethate, imipenem, amikacin, and ampicillin-sulbactam are the most effective treatments. The utilization of β-lactamase inhibitors such as ceftolozane-tazobactam, ceftazidime-avibactam, or imipenem-cilastatin-relebactam has the most efficacy against PDR P. aeruginosa. The PDR K. pneumoniae has been treated in the last decades with tigecycline and colistin, but currently, nitrofurantoin, fosfomycin, and pivmecillinam seem to be the most effective agent for the therapy of PDR E. coli. While these drugs impressively struggle with PDR pathogens, due to the daily increase in antibiotic resistance in microorganisms worldwide, there is still an urgent need for the expansion of novel medicines and methods of combating resistance.

Prevalence of ESBL-Producing Enterobacter Species Resistant to Carbapenems in Iran: A Systematic Review and Meta-Analysis

Background

Carbapenems are the last-line therapy for multidrug-resistant (MDR) infections caused by Enterobacterales, including those caused by Enterobacter species. However, the recent emergence of carbapenem-resistant (CR) and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae pathogens, which are resistant to nearly all antibiotics, has raised concerns among international healthcare organizations. Hence, because there is no comprehensive data in Iran, the current study aimed to evaluate the prevalence of antibiotic resistance among Enterobacter species, especially CR and ESBL-producing strains, in Iran.

Methods

The literature search was performed up to June 21, 2021, in national and international databases using MeSH-extracted keywords, i.e., Enterobacter, antibiotic resistance, carbapenem, ESBL, and Iran. Study selection was done based on the predefined inclusion and exclusion criteria, and data analysis was carried out using the Comprehensive Meta-Analysis (CMA) software.

Results

The pooled prevalence of Enterobacter species resistant to various antibiotics is as follows: imipenem 16.6%, meropenem 16.2%, aztreonam 40.9%, ciprofloxacin 35.3%, norfloxacin 31%, levofloxacin 48%, gentamicin 42.1%, amikacin 30.3%, tobramycin 37.2%, tetracycline 50.1%, chloramphenicol 25.7%, trimethoprim/sulfamethoxazole 52%, nalidixic acid 49.1%, nitrofurantoin 43%, ceftriaxone 49.3%, cefixime 52.4%, cefotaxime 52.7%, ceftazidime 47.9%, cefepime 43.6%, and ceftizoxime 45.5%. The prevalence rates of MDR and ESBL-producing Enterobacter species in Iran were 63.1% and 32.8%, respectively.

Conclusion

In accordance with the warning of international organizations, our results revealed a high prevalence of ESBL-producing Enterobacter species in Iran, which is probably associated with the high prevalence of Enterobacter species resistant to most of the assessed antibiotics, especially MDR strains. However, the resistance rate to carbapenems was relatively low, and these drugs can still be considered as drugs of choice for the treatment of Enterobacter infections in Iran. Nevertheless, continuous monitoring of drug resistance along with antibiotic therapy based on the local data and evaluation of the therapeutic efficacy of new antibiotics or combination therapeutic strategies, such as ceftazidime/avibactam, meropenem/vaborbactam, plazomicin, and eravacycline, is recommended.

Prevalence of Virulence Genes and Drug Resistance Profiles of Pseudomonas aeruginosa Isolated From Clinical Specimens

Background: Drug resistance and virulence genes are two key factors for the colonization of Pseudomonas aeruginosa in settings with high antibiotic pressure, such as hospitals, and the development of hospital-acquired infections. Objectives: The objective of this study was to investigate the prevalence of drug resistance and virulence gene profiles in clinical isolates of P. aeruginosa in Ardabil, Iran. Methods: A total of 84 P. aeruginosa isolates were collected from clinical specimens of Ardabil hospitals and confirmed using laboratory standard tests. The disk diffusion method was used for antibiotic susceptibility testing and polymerase chain reaction (PCR) for the identification of P. aeruginosa virulence genes. Results: The highest and the lowest antibiotic resistance rates of P. aeruginosa strains were against ticarcillin-clavulanate (94%) and doripenem (33.3%), respectively. In addition, the frequency of multidrug-resistant (MDR) P. aeruginosa was 55.9%. The prevalence of virulence factor genes was as follows: algD 84.5%, lasB 86.9%, plcH 86.9%, plcN 86.9%, exoU 56%, exoS 51.2%, toxA 81%, nan1 13.1%, and pilB 33.3%. A significant association was observed between resistance to some antibiotics and the prevalence of virulence genes in P. aeruginosa. Conclusions: Our results revealed a high prevalence of antibiotic resistance, especially MDR, and virulence-associated genes in clinical isolates of P. aeruginosa in Ardabil hospitals. Owing to the low resistance rates against doripenem, gentamicin, and tobramycin, these antibiotics are recommended for the treatment of infections caused by highly resistant and virulent P. aeruginosa strains.

Emergence of rmtD1 gene in clinical isolates of Pseudomonas aeruginosa carrying blaKPC and/or blaVIM-2 genes in Brazil

OBJECTIVES

The aim of the present study is to describe clinical aminoglycoside- or carbapenem-resistant Pseudomonas aeruginosa isolates collected between 2018 and 2019 in a hospital in Recife City, Northeastern Brazil. It was done based on phenotypic and molecular markers of antimicrobial resistance, as well as on the clonal diversity of the investigated isolates.

METHODS

Thirty-four carbapenem- and/or aminoglycoside-resistant P. aeruginosa isolates were collected in a hospital in Recife City-PE, Brazil. Their antimicrobial susceptibility profile was identified based on the automated BD Phoenix ™ system. In addition, broth microdilution was performed to determine the MICs of tobramycin and polymyxin B. Eventually, isolates were subjected to PCR and sequencing in order to detect the carbapenemase enzyme (bla_KPC, bla_NDM, bla_VIM, bla_SPM-1, and bla_IMP) and 16S rRNA methylase (armA, rmtB, rmtD, rmtF, and rmtG) genes; ERIC-PCR was conducted for clonal profile determination purposes.

RESULTS

Thirty-four of the 64 isolates evaluated in the present study were selected for complementary molecular phenotypic tests, based on sample inclusion criteria. The bla_KPC and bla_VIM-2 genes were identified in 32.4% (11/34) and 38.2% (13/34) of tested isolates, respectively. The rmtD1 gene was detected in 32.4% (11/34) of analyzed isolates. Eight isolates carried both the bla_KPC and rmtD1 genes, whereas bla_VIM-2 and rmtD1 genes co-occurrence was detected in three strains; one isolate had all bla_KPC, bla_VIM-2, and rmtD1 genes. ERIC-PCR molecular typing has evidenced cross-transmission of three pathogenic clones among patients in the hospital.

CONCLUSIONS

The present study is a pioneer in describing isolates harboring both bla_VIM-2 and rmtD1 genes. Moreover, it emphasizes the need of conducting local molecular epidemiology studies at different time intervals in order to monitor measures adopted to prevent nosocomial infections in different hospital units.

Prevalence and Characteristics of Metallo-beta-Lactamase-positive and High-risk Clone ST235 Pseudomonas aeruginosa at Ardabil Hospitals

Background: Carbapenems are the most commonly administered drugs for the treatment of multidrug-resistant Pseudomonas aeruginosa (MDR P. aeruginosa) infections. However, carbapenem-resistant P. aeruginosa is spreading rapidly and has led to a new threat to human health worldwide. Objectives: The current study aimed to determine the prevalence of imipenem-resistant P. aeruginosa, detect metallo-β-lactamase (MBL)-producer isolates, and evaluate their clonal relationships in strains isolated from patients referring to the hospitals of Ardabil city, Iran. Methods: The resistance rate to imipenem was evaluated using the disk diffusion method. Double-disk synergy test and PCR technique were used for phenotypic and genotypic screening of MBL-positive P. aeruginosa, respectively. Ultimately, enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and multilocus sequence typing (MLST) methods were used for assessing clonal relatedness among the isolates. Results: The prevalence of imipenem-resistant P. aeruginosa strains was estimated at 57.1% (48 out of 84 isolates). In addition, 45 (93.7%) out of 48 imipenem-resistant P. aeruginosa isolates were phenotypically screened as MBL-positive, among which 16 (35.5%) and three (6.6%) isolates harbored blaIMP and blaVIM-1 genes, respectively. However, blaNDM, blaSIM-2, blaSPM, and blaGIM-1 genes were not detected in this study. MBL-producing P. aeruginosa strains were divided into 42 ERIC-PCR types. Based on the results of MLST, P. aeruginosa ST235 was the only identified sequence type. Conclusions: Our results revealed a high and alarming prevalence of imipenem-resistant and blaIMP-positive P. aeruginosa ST235 at Ardabil hospitals. Continuous monitoring is essential to control the further spread of this highly virulent and drug-resistant clone.

Antibiotic Resistance Pattern in Pseudomonas aeruginosa Isolated from Clinical Samples Other than Burn Samples in Iran

Background

The purpose of this study was to systematically review the prevalence of class 1 integrons, antibiotic resistance pattern in Pseudomonas aeruginosa (P. aeruginosa) isolated from clinical samples other than burn samples.

Methods

The Web of Science, PubMed, Scopus, and Science Direct databases were searched using keywords based on the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The cross-sectional studies published from 1st January 2000 until 1st January 2019 were included which addressed the prevalence of class 1 integrons and antibiotic-resistance in P. aeruginosa isolated from clinical samples other than burn samples. Meta-analysis was conducted using Comprehensive Meta-Analysis (CMA) software. The random-effects model, Cochran's Q and I² tests were applied for statistical analyses.

Results

Eight articles met the eligibility standards for including in the present meta-analysis. The combined prevalence of class 1 integrons in P. aeruginosa isolated from clinical samples other than burn samples was reported by 40% (95% CI:26.1-55.8%). The pooled prevalence of Multi-Drug Resistant (MDR) P. aeruginosa isolates was 70.1%. The highest prevalence of combined antibiotic resistance was related to carbenicillin with a resistance rate of 79.9%. In general, 6 (75%) out of the 8 included studies showed the correlation between the presence of class 1 integrons and antibiotic resistance.

Conclusion

Regarding the correlation between the presence of integrons and the high antibiotic resistance reported by studies included in the present review, there is the need for preventive measures to prevent the spread of resistance by integrons and transferring to other micro-organisms.

Meta-Analysis of Biofilm Formation, Antibiotic Resistance Pattern, and Biofilm-Related Genes in Pseudomonas aeruginosa Isolated from Clinical Samples

Resistant microorganisms such as Pseudomonas aeruginosa grow by developing biofilms in hospitals. We aimed to investigate the biofilm formation and the frequencies of biofilm-related genes and their associations with antibiotic resistance pattern in P. aeruginosa isolated from Iranians' clinical samples. This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We conducted a systematic literature search in scientific databases using medical subject heading terms, including "Pseudomonas aeruginosa," "biofilm formation," "biofilm-related genes," "antibiotic resistance," and "prevalence," to obtain related articles published from 1st January, 2000, to 30th March, 2019. The studies reporting the prevalence of biofilm formation, the frequencies of biofilm-related genes, and the antibiotic resistance pattern in P. aeruginosa retrieved from Iranian patients were included. Meta-analysis was performed using the Comprehensive Meta-Analysis software. The pooled rate of biofilm formation was calculated as 86.5% (95% confidence interval [CI]: 79-91.6). The combined frequencies of strong, moderate, and weak biofilms were 51% (95% CI: 37.4-64.4), 29.2% (95% CI: 20.9-39.1), and 25.4% (95% CI: 11.5-47.2), respectively. The pooled prevalence of laslR, algD, algU, ppyR, and pelF genes were 93.6% (95% CI: 88.1-96.6), 91.4% (95% CI: 80.8-96.4), 89.3% (95% CI: 85.2-92.3), 98.7% (95% CI: 96.5-99.6), and 93% (95% CI: 82.7-97.3), respectively. The highest combined antibiotic resistance rates of P. aeruginosa isolates were against piperacillin/tazobactam (90%). This study showed that biofilm formation was higher in multidrug-resistant (MDR) P. aeruginosa than non-MDRs. A significant correlation was observed between biofilm formation and antibiotic resistance in 50% of studies included in this review.

Evaluation of antimicrobial resistance, biofilm forming potential, and the presence of biofilm-related genes among clinical isolates of Pseudomonas aeruginosa

OBJECTIVES

Pseudomonas aeruginosa is known as a leading cause of nosocomial infections worldwide. Antimicrobial resistance and biofilm production, as two main virulence factors of P. aeruginosa, are responsible for the persistence of prolonged infections. In this study, antimicrobial susceptibility pattern and phenotypic and genotypic characteristics of biofilm of P. aeruginosa were investigated.

RESULTS

A total of 80 clinical P. aeruginosa isolates were obtained. Isolates showed resistance to all antibiotics with a rate from 12.5% (n = 10) against amikacin and piperacillin/tazobactam to 23.75% (n = 19) to levofloxacin. Multidrug-resistant P. aeruginosa accounted for 20% (n = 16). 83.75% (n = 67) of isolates showed biofilm phenotype. All three biofilm-related genes were found simultaneously in 87.5% (n = 70) of P. aeruginosa and 13.5% (n = 10) of the isolates had none of the genes tested. From the results of the present study, combination therapy including an anti-pseudomonal beta-lactam (piperacillin/tazobactam or ceftazidime) and an aminoglycoside or carbapenems (imipenem, meropenem) with fluoroquinolones in conjunction with an aminoglycoside can be used against Pseudomonas infections. However, reasonable antimicrobial use and high standards of infection prevention and control are essential to prevent further development of antimicrobial resistance. Combination strategies based on the proper anti-pseudomonal antibiotics along with anti-biofilm agents can also be selected to eradicate biofilm-associated infections.

In vitro activities of colistin, imipenem and ceftazidime against drug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii isolates in the south of Iran

OBJECTIVE

The present study aimed to determine in vitro activity of colistin and other agents against drug-resistant isolates of Pseudomonas aeruginosa and Acinetobacter baumannii.

RESULTS

This in vitro study performed on a collection of non-fermenting Gram-negative bacilli (NFB) consist of 18 A. baumannii and 21 P. aeruginosa isolates. Non-duplicated isolates (one per patient) were isolated from blood, endotracheal tube and sputum samples of hospitalized patients in the south of Iran. The minimum inhibitory concentrations (MICs) of each isolate was determined using Epsilometer (E)-test strips containing colistin, imipenem, and ceftazidime. In overall, all A. baumannii isolates were non-susceptible to imipenem and ceftazidime. In contrast, all isolates were susceptible to colistin with MIC50 and MIC90 of 0.75/1.5 µg/mL, respectively. Antibiotic susceptibility results showed that 81% and 23.8% of P. aeruginosa isolates were susceptible to ceftazidime and imipenem, respectively. While, all of the P. aeruginosa isolates were susceptible to colistin with MIC50 and MIC90 of 0.5/1 µg/mL, respectively. In summary, colistin showed the promising in vitro activity against drug-resistant strains of two clinically important NFB in our region. However, investigation on a larger collection of drug-resistant strains demands to support these observations in the near future.