Virulence Factors Of Carbapenem-Resistant Pseudomonas aeruginosa In Hospital-Acquired Infections In Mansoura, Egypt

Prevalence of blaOXA-48 and other carbapenemase encoding genes among carbapenem-resistant Pseudomonas aeruginosa clinical isolates in Egypt

BACKGROUND

Resistance to carbapenem, the last line of treatment for gram-negative bacterial infections has been increasing globally and becoming a public health threat. Since integrons may aid in the transmission of resistance genes, the purpose of this study was to detect the frequency of class 1, 2, and 3 integrons as well as carbapenem-resistant genes in clinical isolates of P. aeruginosa that are resistant to carbapenem.

METHODS

This study was carried out on 97 clinical isolates of P. aeruginosa isolated from wound and urine samples. The antimicrobial susceptibility for all isolates was tested by the disc diffusion method. The presence of integrons and carbapenem-resistant genes among carbapenem-resistant P. aeruginosa isolates was evaluated by conventional PCR.

RESULTS

The antimicrobial resistance rate among P. aeruginosa clinical isolates was high, with imipenem resistance in 58.8% of the studied isolates. In this study, 86% of the carbapenem-resistant P. aeruginosa isolates carry carbapenemase genes, with blaVIM being the most common gene followed by the blaOXA-48 gene. Class 1 and class 2 integrons were reported in 37 (64.9%) and 10 (17.5%) of the tested carbapenem-resistant P. aeruginosa isolates, respectively.

CONCLUSION

Our data reported a high prevalence of class 1 integrons in carbapenem-resistant P. aeruginosa clinical isolates, suggesting the important role of integrons in carbapenem-resistant gene transfer among such isolates.

Impact of multidrug resistance on the virulence and fitness of Pseudomonas aeruginosa: a microbiological and clinical perspective

Pseudomonas aeruginosa is one of the most common nosocomial pathogens and part of the top emergent species associated with antimicrobial resistance that has become one of the greatest threat to public health in the twenty-first century. This bacterium is provided with a wide set of virulence factors that contribute to pathogenesis in acute and chronic infections. This review aims to summarize the impact of multidrug resistance on the virulence and fitness of P. aeruginosa. Although it is generally assumed that acquisition of resistant determinants is associated with a fitness cost, several studies support that resistance mutations may not be associated with a decrease in virulence and/or that certain compensatory mutations may allow multidrug resistance strains to recover their initial fitness. We discuss the interplay between resistance profiles and virulence from a microbiological perspective but also the clinical consequences in outcomes and the economic impact.

Phenotypic and genotypic assessment of fluoroquinolones and aminoglycosides resistances in Pseudomonas aeruginosa collected from Minia hospitals, Egypt during COVID-19 pandemic

BACKGROUND

One of the most prevalent bacteria that cause nosocomial infections is Pseudomonas aeruginosa. Fluoroquinolones (FQ) and aminoglycosides are vital antipseudomonal drugs, but resistance is increasingly prevalent. The study sought to investigate the diverse mechanisms underlying FQ and aminoglycoside resistance in various P. aeruginosa strains particularly during the COVID-19 crisis.

METHODS

From various clinical and environmental samples, 110 P. aeruginosa isolates were identified and their susceptibility to several antibiotic classes was evaluated. Molecular techniques were used to track target gene mutations, the presence of genes encoding for quinolone resistance, modifying enzymes for aminoglycosides and resistance methyltransferase (RMT). Efflux pump role was assessed phenotypically and genotypically. Random amplified polymorphic DNA (RAPD) analysis was used to measure clonal diversity.

RESULTS

QnrS was the most frequently encountered quinolone resistance gene (37.5%) followed by qnrA (31.2%) and qnrD (25%). Among aminoglycoside resistant isolates, 94.1% harbored modifying enzymes genes, while RMT genes were found in 55.9% of isolates. The aac(6')-Ib and rmtB were the most prevalent genes (79.4% and 32.3%, respectively). Most FQ resistant isolates overexpressed mexA (87.5%). RAPD fingerprinting showed 63.2% polymorphism.

CONCLUSIONS

Aminoglycosides and FQ resistance observed in this study was attributed to several mechanisms with the potential for cross-contamination existence so, strict infection control practices are crucial.

Characterization and genetic analysis of extensively drug-resistant hospital acquired Pseudomonas aeruginosa isolates

BACKGROUND

The incidence of hospital-acquired infections in extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) has been increasing worldwide and is frequently associated with an increase in mortality and morbidity rates. The aim of this study was to characterize clinical XDR-PA isolates recovered during six months at three different hospitals in Egypt.

RESULTS

Seventy hospital-acquired clinical isolates of P. aeruginosa were classified into multidrug-resistant (MDR), extensively drug-resistant (XDR) and pandrug-resistant (PDR), according to their antimicrobial resistance profile. In addition, the possession of genes associated with mobile genetic elements and genes encoding antimicrobial resistance determinants among isolates were detected using polymerase chain reaction. As a result, a significant percentage of the isolates (75.7%) were XDR, while 18.5% were MDR, however only 5.7% of the isolates were non-MDR. The phenotypic detection of carbapenemases, extended-spectrum β-lactamases (ESBLs) and metallo β-lactamase (MBL) enzymes showed that 73.6% of XDR-PA isolates were carbapenemases producers, whereas 75.5% and 88.7% of XDR-PA isolates produced ESBLs and MBL respectively. In addition, PCR screening showed that oxa gene was the most frequently detected gene of carbapenemases (91.4%), while aac(6')-lb gene was mostly detected (84.3%) among the screened aminoglycosides-resistance genes. Furthermore, the molecular detection of the colistin resistance gene showed that 12.9% of isolates harbored mcr-1 gene. Concerning mobile genetic element markers (intI, traA, tnp513, and merA), intI was the highest detected gene as it was amplified in 67 isolates (95.7%). Finally, phylogenetic and molecular typing of the isolates via ERIC-PCR analysis revealed 10 different ERIC fingerprints.

CONCLUSION

The present study revealed a high prevalence of XDR-PA in hospital settings which were resistant to a variety of antibiotics due to several mechanisms. In addition, 98% of the XDR-PA clinical isolates contained at least one gene associated with movable genetic elements, which could have aided the evolution of these XDR-PA strains. To reduce spread of drug resistance, judicious use of antimicrobial agents and strict infection control measures are therefore essential.

Biofilm Formation by Hospital-Acquired Resistant Bacteria Isolated from Respiratory Samples

BACKGROUND

Hospital-acquired resistant infections (HARI) are infections, which develop 48 h or more after admission to a healthcare facility. HARI pose a considerably acute challenge, due to limited treatment options. These infections are associated bacterial biofilms, which act as a physical barrier to diverse external stresses, such as desiccation, antimicrobials and biocides. We assessed the influence of multiple factors on biofilm production by HARI -associated bacteria.

METHODS

Bacteria were isolated from samples of patients with respiratory HARI who were hospitalized during 2020-2022 in north Israel. Following antibiotic susceptibility testing by disc diffusion or broth microdilution, biofilm formation capacities of resistant bacteria (methicillin-resistant staphylococcus aureus, extended spectrum beta-lactamase-producing Escherichia coli and Klebsiela pneumonia, and multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii) was assessed using the crystalline violet staining method. Data regarding season, time to infection, bacterial species, patient age and gender, year, and medical department were collected from the patient medical records.

RESULTS

Among the 226 study isolates, K. pneumonia was the most prevalent (35.4%) bacteria, followed by P. aeruginosa (23.5%), and methicillin-resistant staphylococcus aureus (MRSA) (21.7%). A significantly higher rate of HARI was documented in 2022 compared to 2020-2021. The majority of isolates (63.3%) were strong biofilm producers, with K. pneumonia (50.3%) being most dominant, followed by P. aeruginosa (29.4%). Biofilm production strength was significantly affected by seasonality and hospitalization length, with strong biofilm production in autumn and in cases where hospitalization length exceeded 30 days.

CONCLUSION

Biofilm production by HARI bacteria is influenced by bacterial species, season and hospitalization length.

Coexistence of plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamase (ESBL) genes among clinical Pseudomonas aeruginosa isolates in Egypt

BACKGROUND

Data about the prevalence of plasmid-mediated quinolone resistance (PMQR) and extended-spectrum beta-lactamase (ESBL) production in P. aeruginosa compared to the Enterobacteriaceae family is limited. The availability of limited therapeutic options raises alarming concerns about the treatment of multidrug-resistant P. aeruginosa. This study aimed to assess the presence of PMQR and ESBL genes among P. aeruginosa strains.

METHODS

Fifty-six P. aeruginosa strains were isolated from 330 patients with different clinical infections. Phenotypically fluoroquinolone-resistant isolates were tested by PCR for the presence of six PMQR genes. Then, blaTEM, blaSHV, and blaCTX-M type ESBL genes were screened to study the co-existence of different resistance determinants.

RESULTS

Overall, 22/56 (39.3%) of the studied P. aeruginosa isolates were phenotypically resistant to fluoroquinolones. PMQR-producing P. aeruginosa isolates were identified in 20 isolates (90.9%). The acc(6')-Ib-cr was the most prevalent PMQR gene (77.3%). The qnr genes occurred in 72.7%, with the predominance of the qnrA gene at 54.5%, followed by the qnrS gene at 27.3%, then qnrB and qnrC at 22.7%. The qepA was not detected in any isolate. The acc(6')-Ib-cr was associated with qnr genes in 65% of positive PMQR isolates. Significant differences between the fluoroquinolone-resistant and fluoroquinolone-susceptible isolates in terms of the antibiotic resistance rates of amikacin, imipenem, and cefepime (P value < 0.0001) were found. The ESBL genes were detected in 52% of cephalosporin-resistant P. aeruginosa isolates. The most frequent ESBL gene was blaCTX-M (76.9%), followed by blaTEM (46.2%). No isolates carried the blaSHV gene. The acc(6')-Ib-cr gene showed the highest association with ESBL genes, followed by the qnrA gene. The correlation matrix of the detected PMQR and ESBL genes indicated overall positive correlations. The strongest and most highly significant correlation was between qnrA and acc(6')-Ib-cr (r = 0.602) and between qnrA and blaCTX-M (r = 0.519).

CONCLUSION

A high prevalence of PMQR genes among the phenotypic fluoroquinolone-resistant P. aeruginosa isolates was detected, with the co-carriage of different PMQR genes. The most frequent PMQR was the acc(6')-Ib-cr gene. Co-existence between PMQR and ESBL genes was found, with 75% of PMQR-positive isolates carrying at least one ESBL gene. A high and significant correlation between the ESBL and PMQR genes was detected.

Safety attributes of Pseudomonas sp. P26, an environmental microorganism with potential application in contaminated environments

Currently, the selection of non-pathogenic microorganisms that lack clinically relevant antimicrobial resistance is crucial to bioaugmentation strategies. Pseudomonas sp. P26 (P26) is an environmental bacterium of interest due to its ability to remove aromatic compounds from petroleum, but its safety characteristics are still unknown. The study aimed to: a) determine P26 sensitivity to antimicrobials, b) investigate the presence of quinolone and β-lactam resistance genes, c) determine the presence of virulence factors, and d) evaluate the effect of P26 on the viability of Galleria mellonella (an invertebrate animal model). P26 antimicrobial sensitivity was determined in vitro using the Kirby-Bauer agar diffusion method and the VITEK 2 automated system (BioMerieux®). Polymerase Chain Reaction was employed for the investigation of genes associated with quinolone resistance, extended-spectrum β-lactamases, and carbapenemases. Hemolysin and protease production was determined in human blood agar and skimmed-milk agar, respectively. In the in vivo assay, different doses of P26 were injected into Galleria mellonella larvae and their survival was monitored daily. Control larvae injected with Pseudomonas putida KT2440 (a strain considered as safe) and Pseudomonas aeruginosa PA14 (a pathogenic strain) were included. Pseudomonas sp. P26 was susceptible to most evaluated antimicrobials, except for trimethoprim-sulfamethoxazole. No epidemiologically relevant genes associated with quinolone and β-lactam resistance were identified. Hemolysin and protease production was only evidenced in the virulent strain (PA14). Furthermore, the results obtained in the in vivo experiment demonstrated that inocula less than 108 CFU/mL of P26 and P. putida KT2440 did not significantly affect larval survival, whereas larvae injected with the lowest dose of the pathogenic strain P. aeruginosa PA14 experienced instant mortality. The results suggest that Pseudomonas sp. P26 is a safe strain for its application in environmental bioremediation processes. Additional studies will be conducted to ensure the safety of this bacterium against other organisms.

Prevalence of the virulence genes and their correlation with carbapenem resistance amongst the Pseudomonas aeruginosa strains isolated from a tertiary hospital in China

Pseudomonas aeruginosa is one of the top-listed pathogens in nosocomial infection. It is notorious for its complicated virulence system and rapid adaptability to drugs or antimicrobials. In this study, we aimed to evaluate the prevalence of sixteen virulence genes in four groups including type III secretion system, biofilm formation, extracellular toxin biosynthesis and enzymes amongst 209 clinical Pseudomonas aeruginosa strains. We investigated the different distribution patterns of virulence genotypes based on carbapenem-resistant phenotype or the carriage of carbapenemase genes. The detection rate of each virulence gene varied greatly. phzM and plcN were detected in all collected strains, while pilB and exoU were only carried by a small portion of isolates (6.7% and 16.3%). Additionally, the number of genotypes observed in each group of examined virulence genes ranged from 4 to 8. Only the distribution of genotypes of type III secretion system showed statistical difference between carbapenem-mediated or carbapenem-resistant and carbapenem-sensitive strains. The virulence genotype of Pseudomonas aeruginosa was possibly interrelated to its resistance mechanism. Further research suggested that one particular TTSS genotype exhibited higher ratio in carbapenemase-producing strains and exoS was less frequently detected in CRPA strains carrying carbapenemase gene. Generally, the significant genetic diversity of virulence genes amongst Pseudomonas aeruginosa strains was highlighted in this study. Specific TTSS genotypes were associated with carbapenem-resistance. In particular, certain incompatibility might exist between exoS and carbapenemase genes, which provided valuable information for further understanding the relationship between carbapenem resistance and virulence.

Phenotypic and genomic characterization of Pseudomonas aeruginosa isolates recovered from catheter-associated urinary tract infections in an Egyptian hospital

Catheter-associated urinary tract infections (CAUTIs) represent one of the major healthcare-associated infections, and Pseudomonas aeruginosa is a common Gram-negative bacterium associated with catheter infections in Egyptian clinical settings. The present study describes the phenotypic and genotypic characteristics of 31 P. aeruginosa isolates recovered from CAUTIs in an Egyptian hospital over a 3 month period. Genomes of isolates were of good quality and were confirmed to be P. aeruginosa by comparison to the type strain (average nucleotide identity, phylogenetic analysis). Clonal diversity among the isolates was determined; eight different sequence types were found (STs 244, 357, 381, 621, 773, 1430, 1667 and 3765), of which ST357 and ST773 are considered to be high-risk clones. Antimicrobial resistance (AMR) testing according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines showed that the isolates were highly resistant to quinolones [ciprofloxacin (12/31, 38.7 %) and levofloxacin (9/31, 29 %) followed by tobramycin (10/31, 32.5 %)] and cephalosporins (7/31, 22.5 %). Genotypic analysis of resistance determinants predicted all isolates to encode a range of AMR genes, including those conferring resistance to aminoglycosides, β-lactamases, fluoroquinolones, fosfomycin, sulfonamides, tetracyclines and chloramphenicol. One isolate was found to carry a 422 938 bp pBT2436-like megaplasmid encoding OXA-520, the first report from Egypt of this emerging family of clinically important mobile genetic elements. All isolates were able to form biofilms and were predicted to encode virulence genes associated with adherence, antimicrobial activity, anti-phagocytosis, phospholipase enzymes, iron uptake, proteases, secretion systems and toxins. The present study shows how phenotypic analysis alongside genomic analysis may help us understand the AMR and virulence profiles of P. aeruginosa contributing to CAUTIs in Egypt.

Understanding resistance acquisition by Pseudomonas aeruginosa and possible pharmacological approaches in palliating its pathogenesis

Pseudomonas aeruginosa can utilize various virulence factors necessary for host infection and persistence. These virulence factors include pyocyanin, proteases, exotoxins, 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), phospholipases, and siderophores that enable the bacteria to cause severe infections in immunocompromised individuals. P. aeruginosa falls into the category of nosocomial pathogens that are typically resistant to available antibiotics and therapeutic approaches. P. aeruginosa bio-film formation is a major concern in hospitals because it can cause chronic infection and increase the risk of mortality. Therefore, the development of new strategies to disrupt biofilm formation and improve antibiotic efficacy for the treatment of P. aeruginosa infections is crucial. Anti-biofilm and anti-quorum sensing (QS) activity can be viewed as an anti-virulence approach to control the infectious nature of P. aeruginosa. Inhibition of QS and biofilm formation can be achieved through pharmacological approaches such as phytochemicals and essential oils, which have shown promising results in laboratory studies. A regulatory protein called LasR plays a key role in QS signaling to coordinate gene expression. Designing an antagonist molecule that mimics the natural autoinducer might be the best approach for LasR inhibition. Here we reviewed the mechanism behind antibiotic resistance and alternative approaches to combat the pathogenicity of P. aeruginosa.

Prevalence of different virulence factors and their association with antimicrobial resistance among Pseudomonas aeruginosa clinical isolates from Egypt

BACKGROUND

Emergence of multi-drug resistant Pseudomonas aeruginosa, coupled with the pathogen's versatile virulence factors, lead to high morbidity and mortality rates. The current study investigated the potential association between the antibiotic resistance and the production of virulence factors among P. aeruginosa clinical isolates collected from Alexandria Main University Hospital in Egypt. We also evaluated the potential of the phenotypic detection of virulence factors to reflect virulence as detected by virulence genes presence. The role of alginate in the formation of biofilms and the effect of ambroxol, a mucolytic agent, on the inhibition of biofilm formation were investigated.

RESULTS

A multi-drug resistant phenotype was detected among 79.8% of the isolates. The most predominant virulence factor was biofilm formation (89.4%), while DNase was least detected (10.6%). Pigment production was significantly associated with ceftazidime susceptibility, phospholipase C production was significantly linked to sensitivity to cefepime, and DNase production was significantly associated with intermediate resistance to meropenem. Among the tested virulence genes, lasB and algD showed the highest prevalence rates (93.3% and 91.3%, respectively), while toxA and plcN were the least detected ones (46.2% and 53.8%, respectively). Significant association of toxA with ceftazidime susceptibility, exoS with ceftazidime and aztreonam susceptibility, and plcH with piperacillin-tazobactam susceptibility was observed. There was a significant correlation between alkaline protease production and the detection of algD, lasB, exoS, plcH and plcN; pigment production and the presence of algD, lasB, toxA and exoS; and gelatinase production and the existence of lasB, exoS and plcH. Ambroxol showed a high anti-biofilm activity (5% to 92%). Quantitative reverse transcriptase polymerase chain reaction showed that alginate was not an essential matrix component in P. aeruginosa biofilms.

CONCLUSIONS

High virulence coupled with the isolates' multi-drug resistance to commonly used antimicrobials would increase morbidity and mortality rates among P. aeruginosa infections. Ambroxol that displayed anti-biofilm action could be suggested as an alternative treatment option, yet in vivo studies are required to confirm these findings. We recommend active surveillance of antimicrobial resistance and virulence determinant prevalence for better understanding of coregulatory mechanisms.

Impact of Mt. Olympus Honeys on Virulence Factors Implicated in Pathogenesis Exerted by Pseudomonas aeruginosa

The aim of this study was to examine the impact of twenty honey samples, harvested in Mt. Olympus (Greece), on the virulence factors implicated in P. aeruginosa pathogenesis. Six key virulence factors (protease and elastase activity, pyocyanin and pyoverdine concentration, biofilm formation, and swimming motility) were selected in order to assess the effect of the tested honeys compared with Manuka honey. All tested honeys demonstrated a significant inhibition of protease and elastase activity compared with the control. Six and thirteen honeys exerted superior protease (no inhibition zone) and elastase (values lower than 55%) activity, respectively, compared with Manuka honey. Seventeen tested honeys exhibited reduced pyoverdine production compared with the control; all tested honeys, except for one, showed an inhibitory effect on pyocyanin production compared with the control. Regarding swimming motility, nine tested honeys demonstrated significantly higher inhibition compared with Manuka honey. Honey concentrations (6% v/v and 8% v/v) had the most profound impact, as they reduced biofilm formation to less than 20% compared with the control. Overall, our data demonstrate a significant inhibition of the virulence factors in the tested Mt. Olympus honeys, highlighting the strong antimicrobial activity against P. aeruginosa, an antibiotic-resistant pathogen of growing concern, which is implicated in severe nosocomial infections globally.

Investigation of antimicrobial resistance patterns and molecular typing of Pseudomonas aeruginosa isolates among Coronavirus disease-19 patients

BACKGROUND

Pseudomonas aeruginosa is a common co-infecting pathogen recognized among COVID-19 patients. We aimed to investigate the antimicrobial resistance patterns and molecular typing of Pseudomonas aeruginosa isolates among Coronavirus disease-19 patients.

METHODS

Between December 2020 and July 2021, 15 Pseudomonas aeruginosa were isolated from COVID-19 patients in the intensive care unit at Sina Hospital in Hamadan, west of Iran. The antimicrobial resistance of the isolates was determined by disk diffusion and broth microdilution methods. The double-disk synergy method, Modified Hodge test, and polymerase chain reaction were utilized to detect Pseudomonas aeruginosa extended spectrum beta-lactamase and carbapenemase producers. Microtiter plate assay was performed to evaluate the biofilm formation ability of the isolates. The isolates phylogenetic relatedness was revealed using the multilocus variable-number tandem-repeat analysis method.

RESULTS

The results showed Pseudomonas aeruginosa isolates had the most elevated resistance to imipenem (93.3%), trimethoprim-sulfamethoxazole (93.3%), ceftriaxone (80%), ceftazidime (80%), gentamicin (60%), levofloxacin (60%), ciprofloxacin (60%), and cefepime (60%). In the broth microdilution method, 100%, 100%, 20%, and 13.3% of isolates showed resistance to imipenem, meropenem, polymyxin B, and colistin, respectively. Ten (66.6%) isolates were identified as multiple drug resistance. Carbapenemase enzymes and extended spectrum beta-lactamases were identified in 66.6% and 20% of the isolates, respectively and the biofilm formation was detected in 100% of the isolates. The blaOXA-48, blaTEM, blaIMP, blaSPM, blaPER, blaVEB, blaNDM, blaSHV, and blaCTX-M genes were detected in 100%, 86.6%, 86.6%, 40%, 20%, 20%, 13.3%, 6.6%, and 6.6% of the isolates, respectively. The blaVIM, blaGIM, blaGES, and blaMCR-1 genes were not identified in any of the isolates. The MLVA typing technique showed 11 types and seven main clusters and most isolates belong to cluster I, V and VII.

CONCLUSION

Due to the high rate of antimicrobial resistance, as well as the genetic diversity of Pseudomonas aeruginosa isolates from COVID-19 patients, it is indispensable to monitor the antimicrobial resistance pattern and epidemiology of the isolates on a regular basis.

Bacterial Resistance in Hospital-Acquired Infections Acquired in the Intensive Care Unit: A Systematic Review

PURPOSE

In this review we present the status of the prevalence of bacteria resistant to antibiotics and the main antibiotic resistance genes that are reported in infections acquired in intensive care units (ICU) around the world.

METHODS

A systematic review based on the PRISMA guide was carried out, from the Science Direct, Redalyc, Scopus, Hinari, Scielo, Dialnet, PLOS, ProQuest, Taylor, Lilacs and PubMed/Medline databases. Inclusion criteria of this review were original research study published in a scientific journal in a 10-year time span from 1 January 2017 and 30 April 2022.

RESULTS

A total of 1686 studies were identified, but only 114 studies were considered eligible for inclusion. Klebsiella pneumoniae and Escherichia coli resistant to carbapenems and producers of extended-spectrum β-lactamases (ESBL) are the most frequently isolated pathogens in ICUs in Asia, Africa and Latin America. The blaOXA and blaCTX were antibiotic resistance genes (ARG) most commonly reported in different geographic regions (in 30 and 28 studies, respectively). Moreover, multidrug-resistant (MDR) strains were reported in higher frequency in hospital-acquired infections. Reports of MDR strains vary between continents, with the majority of publications being in Asia and between countries, with Egypt and Iran being highlighted. There is a predominance of few bacterial clones with MDR phenotype, for example, clonal complex 5 Methicillin-Resistant Staphylococcus aureus (CC5-MRSA) circulates frequently in hospitals in the United States, clone ST23-K. pneumoniae is reported in India and Iran, and clone ST260 carbapenemase-producing P. aeruginosa in the United States and Estonia.

CONCLUSION

Our systematic review reveals that ESBL- and carbapenemase-producing K. pneumoniae and E. coli are the most problematic bacteria that are reported, mainly in tertiary hospitals in Asia, Africa, and Latin America. We have also found propagation of dominant clones with a high degree of MDR, becoming a problem due to its high capacity to cause morbidity, mortality and additional hospital costs.

Decoding Genetic Features and Antimicrobial Susceptibility of Pseudomonas aeruginosa Strains Isolated from Bloodstream Infections

Pseudomonas aeruginosa is a Gram-negative rod and an etiological factor of opportunistic infections. The infections of this etiology appear mostly among hospitalized patients and are relatively hard to treat due to widespread antimicrobial resistance. Many virulence factors are involved in the pathogenesis of P. aeruginosa infection, the coexistence of which have a significant impact on the course of an infection with a particular localization. The aim of this study was to assess the antimicrobial susceptibility profiles and the frequency of genes encoding selected virulence factors in clinical P. aeruginosa strains isolated from bloodstream infections (BSIs). The following genes encoding virulence factors of enzymatic activity were assessed: lasB, plC H, plC N, nan1, nan2, aprA and phzM. The frequency of the genes encoding the type III secretion system effector proteins (exoU and exoS) and the genes encoding pilin structural subunits (pilA and pilB) were also investigated. The occurrence of virulence-factor genes was assessed using polymerase chain reactions, each in a separate reaction. Seventy-one P. aeruginosa strains, isolated from blood samples of patients with confirmed bacteremia hospitalized at the University Hospital No. 1 of Dr. Antoni Jurasz in Bydgoszcz, Poland, were included in the study. All the investigated strains were susceptible to colistin, while the majority of the strains presented resistance to ticarcillin/clavulanate (71.8%), piperacillin (60.6 %), imipenem (57.7%) and piperacillin/tazobactam (52.1%). The presence of the lasB and plC H genes was noted in all the tested strains, while the plC N, nan2, aprA, phzM and nan1 genes were identified in 68 (95.8%), 66 (93.0%), 63 (88.7%), 55 (77.5%) and 34 (47.9%) isolates, respectively. In 44 (62.0%) and 41 (57.7%) strains, the presence of the exoU and exoS genes was confirmed, while the pilA and pilB genes were noted only in 14 (19.7%) and 3 (4.2%) isolates, respectively. This may be due to the diverse roles of these proteins in the development and maintenance of BSIs. Statistically significant correlations were observed between particular gene pairs’ coexistence (e.g., alkaline protease and neuraminidase 2). Altogether, twenty-seven distinctive genotypes were observed among the studied strains, indicating the vast variety of genetic compositions of P. aeruginosa strains causing BSIs.

Presence of quorum sensing system, virulence genes, biofilm formation and relationship among them and class 1 integron in carbapenem-resistant clinical Pseudomonas aeruginosa isolates

Carbapenems are the most effective agents for treating clinical P. aeruginosa (PsA) infections. During an infection, a quorum-sensing (QS) system and its regulating virulence genes have a great role. The aim of the study was to detect the presence of a las and rhl QS system and related virulence genes, biofilm formation and a class 1 (Cls1) integron. A total of 52 carbapenem-resistant PsA (CRPsA) isolates obtained from Kastamonu, Turkey was analyzed. For the isolation and identification of CRPsA isolates, a conventional culture method, an automated VITEK-2 compact system, and oprL gene-based molecular technique were applied. The two QS system genes were detected in 51 (98.1%), and co-existed of four two QS system genes (lasI/R and rhIl/R genes) were determined in 41 (78.8%) of the isolates. algD, lasB, toxA and aprA genes were detected in between 46.1 and 88.5%, and co-existence of four two QS system genes with four virulence genes were detected in 40.4% of the isolates. Biofilm formation using microtiter plate assay and slime production using Congo Red Agar and Cls1 integron were determined in 84.6%, 67.3% and 51.9% of the isolates, respectively. According to statistical analyses results, there was a significant positive correlation (p < .10) between the las and the rhl systems and a strongly and positive correlation (p < .01 or p < .05) between the rhl system-three virulence genes and slime production-and among some virulence genes. In conclusion, the CRPsA isolates tested in the study are highly virulent and QS systems have a significant role in pathogenesis.

Antibiotic resistance of Pseudomonas aeruginosa isolated from hospital wastewater in the Czech Republic

Resistant bacteria may leave the hospital environment through wastewater. The opportunistic pathogen Pseudomonas aeruginosa, due to its intrinsic resistance to many antibiotics and its ability to easily acquire antibiotic resistance determinants, poses a significant threat to public health. The aim of this study was to evaluate the antibiotic resistance profiles of cultivated P. aeruginosa in untreated hospital effluents in the Czech Republic. Fifty-nine P. aeruginosa strains isolated from six hospital wastewaters were tested for antimicrobial susceptibility through the disc diffusion method against seven antimicrobial agents. Resistance was found in all antibiotics tested. The highest resistance values were observed for ciprofloxacin (30.5%), gentamicin (28.8%), and meropenem (27.2%). The P. aeruginosa isolates also exhibited resistance to ceftazidime (11.5%), amikacin (11.5%), piperacillin-tazobactam (11.5%), and aztreonam (8.5%). Seventeen strains of P. aeruginosa (28.8%) were classified as multidrug-resistant (MDR). The results of this study revealed that antibiotic-resistant strains are commonly present in hospital wastewater and are resistant to clinically relevant antipseudomonal drugs. In the absence of an appropriate treatment process for hospital wastewater, resistant bacteria are released directly into public sewer networks, where they can serve as potential vectors for the spread of antibiotic resistance.

Antibiotic resistance, biofilm production ability and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa strains isolated from nosocomial infections in southwestern Iran

Background

This study was aimed to evaluate the antibiotic resistance, biofilm formation, and genetic diversity of carbapenem-resistant Pseudomonas aeruginosa (CRPA) strains isolated from four types of nosocomial infections (NIs) including urinary tract infection (UTI), ventilator-associated pneumonia (VAP), surgical site infection (SSI), and bloodstream infection (BSI).

Methods and results

In total, 115 isolates of NIs-causing P. aeruginosa were collected from NIs. Antibiotic susceptibility testing (AST) was performed using disk diffusion method and minimum inhibitory concentrations. Biofilm formation was tested on 96-well polystyrene microtiter plates (MTP). CRPA isolates were genotyped using multiple-locus variable number of tandem repeat analysis (MLVA). The most resistance and susceptibility rates were observed to amikacin (70.6%) and colistin (96.1%), respectively. Colistin and meropenem were the most active antimicrobial agents in VAP, SSI, and BSI. While, colistin and cefepime were the most active in UTIs. In total, 52.2% (n = 60/115) of P. aeruginosa isolates were carbapenem resistant, of which 95.0%, 55.0%, and 5.0% were multidrug-resistant, extensively drug-resistant, and pandrug-resistant, respectively. There was a significant association between resistance to carbapenem and resistance to other antibiotics except for piperacillin/tazobactam. The biofilm production of CRPA isolates was 95.0%, of which 23.3% were strong biofilm producers. Based on MLVA, there were 34 different types of CRPA isolates classified into three main clusters and 5 sub clusters.

Conclusion

The association of CRPA with other antibiotic resistance, the high rates of biofilm production, and the high genetic diversity of the isolates may be a warning of the need for a careful surveillance program.

Epidemiology, Molecular Characteristics, and Virulence Factors of Carbapenem-Resistant Pseudomonas aeruginosa Isolated from Patients with Urinary Tract Infections

Purpose

Pseudomonas aeruginosa is an important pathogen that causes urinary tract infections. Carbapenems are the drugs of choice for the treatment of P. aeruginosa infections. However, the emergence and spread of carbapenem-resistant P. aeruginosa (CRPA) is a serious global health threat. In this study, we investigated the epidemiology, molecular characteristics, drug resistance, and virulence factors of CRPA isolated from urine samples.

Methods

A total of 124 P. aeruginosa isolates were obtained from urine samples collected between March 2020 and February 2021. Clonal relatedness was evaluated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). We performed antimicrobial susceptibility tests and investigated the presence of carbapenemase genes and virulence factors in CRPA isolates.

Results

The carbapenem resistance rate of the isolated P. aeruginosa was 46.7% (59/124). A total of 54 (91.5%) out of the 59 CRPA isolates were identified as multidrug-resistant. The majority of the CRPA isolates (81.4%, 48/59) harbored carbapenemase genes, such as bla_IMP-6 or bla_NDM-1. In an epidemiological analysis using MLST, 88.1% of CRPA isolates were confirmed to be ST773 (50.8%, 30/59) or ST235 (37.3%, 22/59). The CRPA isolates harboring bla_IMP-6 and bla_NDM-1 belonged to ST235 (PFGE pulsotypes E1-E18, F) and ST773 (PFGE pulsotypes H1-H2, I1-I16) subtypes, respectively. The studied CRPA isolates simultaneously harbored 10 to 14 virulence factors of the 16 virulence factors examined. Nine virulence factor genes (toxA, exoT, plcH, plcN, phzM, phzS, lasB, aprA, and algD) were identified in all CRPA isolates.

Conclusion

Our study shows that P. aeruginosa ST235 harboring bla_IMP-6 and ST773 harboring bla_NDM-1—known internationally as high-risk clones with multiple virulence factors—are widely spread in the study area. These findings suggest that continuous monitoring is necessary to prevent the further spread of carbapenemase-producing CRPA.

High Rates of Aminoglycoside Methyltransferases Associated with Metallo-Beta-Lactamases in Multidrug-Resistant and Extensively Drug-Resistant Pseudomonas aeruginosa Clinical Isolates from a Tertiary Care Hospital in Egypt

BACKGROUND

Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Pseudomonas aeruginosa are the leading cause of healthcare-associated infections worldwide.

OBJECTIVE

The aim was to identify the resistant phenotypes among P. aeruginosa and to characterize different aminoglycosides and carbapenem resistance genes as major mechanisms of resistance in these isolates, in Theodor Bilharz Research Institute (TBRI), a tertiary care hospital in Cairo, Egypt.

METHODS

During a period of 11 months, 42 P. aeruginosa clinical isolates were collected from the microbiology laboratory by routine culture. Antimicrobial sensitivity testing to the aminoglycosides gentamicin and amikacin, and other classes of antibiotics, was performed by a disk diffusion method. Isolates were tested for aminoglycoside resistance genes, aac(6')-lb, aac-(3)-lla, rmtB, rmtC, armA, rmtD, and rmtF, and carbapenemase resistance genes bla NDM, bla VIM, and bla IMP, using conventional PCR.

RESULTS

Thirty-three (78.5%) of the clinical P. aeruginosa isolates showed MDR and XDR phenotypes at 42.4% and 57.65%, respectively, and these were included in the study. Aminoglycoside resistance was found in 97%, whereas carbapenem resistance was found in 81% of the isolates phenotypically. Only 59.4% (19/26) of the aminoglycoside-resistant isolates harbored resistance genes; none of the amikacin-susceptible isolates harbored any of the tested aminoglycoside resistance genes. Aminoglycoside resistance genes rmtB, armA, aac(6')-lb, and rmtF were found at rates of 17/33 (51.5%), 3/33 (9%), 2/33 (6%), and 2/33 (6%), respectively, whereas rmtD, acc(3)-II, and rmtC were not detected. Only 40.7% (11/27) of the carbapenem-resistant isolates harbored resistance genes. Carbapenem resistance genes, bla NDM andbla VIM, were found at rates of 7/33 (21.2%) and 6/33 (18.1%), respectively, and bla IMP was not detected.

CONCLUSION

Rates of MDR and XDR P. aeruginosa and resistance to aminoglycosides and carbapenems in our setting are high. Methyltransferases and metallo-beta-lactamases are the main mechanisms of resistance to aminoglycosides and carbapenems, respectively. The presence of bla NDM and rmtF in the strains confirms their rapid dissemination in the Egyptian environment.

Occurrence, virulence, carbapenem resistance, susceptibility to disinfectants and public health hazard of Pseudomonas aeruginosa isolated from animals, humans and environment in intensive farms

AIMS

This work aimed to determine the occurrence, virulence, antibiogram, carbapenem resistance genes and susceptibility to disinfectants of Pseudomonas aeruginosa isolated from animals, environment and workers in intensive farms.

METHODS AND RESULTS

A total of 610 samples from intensive beef cattle and sheep farms in Kafr El Sheikh Governorate, Egypt were screened for the presence of P. aeruginosa using bacteriological assays. The isolates were characterized by PCR and tested for susceptibility to antibiotics using disk diffusion method and disinfectants by quantitative suspension test. In all, 60 P. aeruginosa isolates were recovered in this study and all isolates harboured at least one of the virulence genes tested. Human P. aeruginosa isolates were highly resistant to cephalosporins, fluroquinolones, aminoglycosides, carbapenems and penicillins+β-lactamase inhibitors than non-human isolates. Colistin resistance was higher in non-human than human P. aeruginosa isolates, whereas low resistance to aztreonam was observed in non-human and human isolates. Carbapenem-resistant P. aeruginosa (CRPA) strains were recovered from workers (56.5%), sheep (8.3%) and cattle (8.3%). All CRPA harboured at least one of the carbapenem resistance genes tested and most of them showed multidrug resistance (MDR) or extensive drug resistance (XDR) phenotypes. Glutaraldehyde 1% and hydrogen peroxide 3% eliminated P. aeruginosa completely in the absence and presence of organic matter within short contact time compared with other disinfectants.

CONCLUSIONS

This study reported the occurrence of CRPA in animals and workers in intensive farms. Glutaraldehyde and hydrogen peroxide were the most effective disinfectants against P. aeruginosa.

SIGNIFICANCE AND IMPACT OF THE STUDY

The occurrence of CRPA in intensive livestock farms is a serious challenge that threatens animal and human health and increases the risk of P. aeruginosa infection in the community. Therefore, it is vital to control the spread of CRPA by banning or restricting the use of antibiotics and applying proper cleaning and disinfection protocols in livestock farms.

Landscape of Multidrug-Resistant Gram-Negative Infections in Egypt: Survey and Literature Review

Purpose

This article is the first to review published reports on the prevalence of multidrug-resistant (MDR) gram-negative infections in Egypt and gain insights into antimicrobial resistance (AMR) surveillance and susceptibility testing capabilities of Egyptian medical centers.

Materials and Methods

A literature review and online survey were conducted.

Results

The online survey and literature review reported high prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (19–85.24% of E. coli, and 10–87% of K. pneumoniae), carbapenem-resistant Enterobacteriaceae (35–100% of K. pneumoniae and 13.8–100% of E. coli), carbapenem-resistant Acinetobacter baumannii (10–100%), and carbapenem-resistant Pseudomonas aeruginosa (15–70%) in Egypt. Risk factors for MDR Gram-negative infections were ventilated patients (67.4%), prolonged hospitalization (53.5%) and chronic disease (34.9%). Although antimicrobial surveillance capabilities were deemed at least moderate in most centers, lack of access to rapid AMR diagnostics, lack of use of local epidemiological data in treatment decision-making, lack of antimicrobial stewardship (AMS) programs, and lack of risk prediction tools were commonly reported by respondents.

Conclusion

This survey has highlighted the presence of knowledge gaps as well as limitations in the surveillance and monitoring capabilities of AMR in Egypt, with most laboratories lacking rapid diagnostics and molecular testing. Future efforts in Egypt should focus on tackling these issues via nationwide initiatives, including understanding the AMR trends in the country, capacity building of laboratories and their staff to correctly and timely identify AMR, and introducing newer antimicrobials for targeting emerging resistance mechanisms in Gram-negative species.

Epidemiology of Multidrug-Resistant Pseudomonas aeruginosa in the Middle East and North Africa Region

Over the last decades, there has been a dramatic global increase in multidrug-resistant (MDR) pathogens particularly among Gram-negative bacteria (GNB). Pseudomonas aeruginosa is responsible for various health care-associated infections, while MDR P. aeruginosa causes significant morbidity and mortality. Middle East and North Africa (MENA) represent an unexplored geographical region for the study of drug resistance since many of these countries are at crossroads of high volume of travel, diverse expatriate populations, as well as high antibiotic consumption despite attempts to implement antimicrobial stewardship programs. This minireview analyzes epidemiology, microbiological, and genomic characteristics of MDR P. aeruginosa in the MENA region. Published data on MDR P. aeruginosa prevalence, antimicrobial resistance patterns, and genetic profiles from studies published during the past 10 years from 19 MENA countries have been included in this minireview. There is wide variation in the epidemiology of MDR P. aeruginosa in the MENA region in terms of prevalence, antimicrobial characteristics, as well as genetic profiles. Overall, there is high prevalence of MDR P. aeruginosa seen in the majority of the countries in the MENA region with similarities between neighboring countries, which might reflect comparable population and antibiotic-prescribing cultures. Isolates from critical care units are significantly resistant particularly from certain countries such as Saudi Arabia, Egypt, Libya, Syria, and Lebanon with high-level resistance to cephalosporins, carbapenems, and aminoglycosides. Colistin susceptibility patterns remains high apart from countries with high-level antibiotic resistance such as Saudi Arabia, Syria, and Egypt.

Transcriptomic Analysis of Pseudomonas aeruginosa Response to Pine Honey via RNA Sequencing Indicates Multiple Mechanisms of Antibacterial Activity

Pine honey is a unique type of honeydew honey produced exclusively in Eastern Mediterranean countries like Greece and Turkey. Although the antioxidant and anti-inflammatory properties of pine honey are well documented, few studies have investigated so far its antibacterial activity. This study investigates the antibacterial effects of pine honey against P. aeruginosa PA14 at the molecular level using a global transcriptome approach via RNA-sequencing. Pine honey treatment was applied at sub-inhibitory concentration and short exposure time (0.5× of minimum inhibitory concentration –MIC- for 45 min). Pine honey induced the differential expression (>two-fold change and p ≤ 0.05) of 463 genes, with 274 of them being down-regulated and 189 being up-regulated. Gene ontology (GO) analysis revealed that pine honey affected a wide range of biological processes (BP). The most affected down-regulated BP GO terms were oxidation-reduction process, transmembrane transport, proteolysis, signal transduction, biosynthetic process, phenazine biosynthetic process, bacterial chemotaxis, and antibiotic biosynthetic process. The up-regulated BP terms, affected by pine honey treatment, were those related to the regulation of DNA-templated transcription, siderophore transport, and phosphorylation. Pathway analysis revealed that pine honey treatment significantly affected two-component regulatory systems, ABC transporter systems, quorum sensing, bacterial chemotaxis, biofilm formation and SOS response. These data collectively indicate that multiple mechanisms of action are implicated in antibacterial activity exerted by pine honey against P. aeruginosa.

Prevalence of the Genes Associated with Biofilm and Toxins Synthesis amongst the Pseudomonas aeruginosa Clinical Strains

Pseudomonas aeruginosa is one of the most commonly isolated bacteria from clinical specimens, with an increasing isolation frequency in nosocomial outbreaks. The hypothesis tested was whether carbapenem-resistant P. aeruginosa strains display an altered carriage of the virulence factor genes, depending on the type of carbapenem resistance. The aim of the study was to investigate, by PCR, the frequency of 10 chosen virulence factors genes (phzM, phzS, exoT, exoY, exoU, toxA, exoS, algD, pilA and pilB) and the genotype distribution in 107 non-duplicated carbapenem-resistant P. aeruginosa isolates. P. aeruginosa genes involved in phenazine dyes and exoenzyme T synthesis were noted with the highest frequency (100%). Fimbriae-encoding genes were detected with the lowest incidence: 15.9% and 4.7% for pilin A and B, respectively. The differences observed between the exoS gene prevalence amongst the carbapenemase-positive and the carbapenemase-negative strains and the pilA gene prevalence amongst the strains of different origins were statistically significant. Virulence genes’ prevalence and the genotype distribution vary amongst P. aeruginosa strains resistant to carbapenems, especially in terms of their carbapenemase synthesis ability and the strain origin.

Transcriptomic Response in Pseudomonas aeruginosa towards Treatment with a Kaempferol Isolated from Melastoma malabathricum Linn Leaves

Pseudomonas aeruginosa is one of the main causes of nosocomial infections and is frequently associated with opportunistic infections among hospitalized patients. Kaempferol-3-O-(2′,6′-di-O-trans-p-coumaroyl)-β-D glucopyranoside (K_F) is an antipseudomonal compound isolated from the leaves of the native medicinal plant Melastoma malabathricum. Herein, an RNA-seq transcriptomic approach was employed to study the effect of K_F treatment on P. aeruginosa and to elucidate the molecular mechanisms underlying the response to K_F at two time points (6 h and 24 h incubation). Quantitative real-time PCR (qRT-PCR) was performed for four genes (uvrD, sodM, fumC1, and rpsL) to assess the reliability of the RNA-seq results. The RNA-seq transcriptomic analysis revealed that K_F increases the expression of genes involved in the electron transport chain (NADH-I), resulting in the induction of ATP synthesis. Furthermore, K_F also increased the expression of genes associated with ATP-binding cassette transporters, flagella, type III secretion system proteins, and DNA replication and repair, which may further influence nutrient uptake, motility, and growth. The results also revealed that K_F decreased the expression of a broad range of virulence factors associated with LPS biosynthesis, iron homeostasis, cytotoxic pigment pyocyanin production, and motility and adhesion that are representative of an acute P. aeruginosa infection profile. In addition, P. aeruginosa pathways for amino acid synthesis and membrane lipid composition were modified to adapt to K_F treatment. Overall, the present research provides a detailed view of P. aeruginosa adaptation and behaviour in response to K_F and highlights the possible therapeutic approach of using plants to combat P. aeruginosa infections.