Pathogenic Factors Correlate With Antimicrobial Resistance Among Clinical Proteus mirabilis Strains

Potential antivirulence activity of sub-inhibitory concentrations of ciprofloxacin against Proteus mirabilis isolates: an in-vitro and in-vivo study

BACKGROUND

Proteus mirabilis is a significant nosocomial pathogen that is frequently associated with a wide range of infections, necessitating heightened attention to mitigate potential health risks. Hence, this study was performed to investigate the impact of sub-minimum inhibitory concentrations (MICs) of ciprofloxacin (CIP) on Proteus mirabilis clinical isolates.

METHODS

The sub-MICs of CIP were selected using the growth curve approach. The untreated and treated isolates with sub-MICs of CIP were assessed for their biofilm development, motilities on agar, and other virulence factors. The cell morphology of untreated and treated isolates with sub-MIC of CIP was explored using electron microscope. Moreover, the expression levels of the virulence genes in isolates were measured using quantitative real-time PCR.

RESULTS

Data revealed that sub-MICs of CIP significantly (p < 0.05), in a concentration-dependent manner, inhibited biofilm formation and other virulence factors in the selected isolates. Electron microscope analysis showed cell enlargement and various abnormalities in the cell wall and membrane integrity.

CONCLUSION

Sub-MICs of CIP exhibited inhibition of virulence and alterations in morphological integrity against P. mirabilis isolates.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

Emergence and genomic chion of Proteus mirabilis harboring blaNDM-1 in Korean companion dogs

Proteus mirabilis is a commensal bacterium dwelling in the gastrointestinal (GI) tract of humans and animals. Although New Delhi metallo-β-lactamase 1 (NDM-1) producing P. mirabilis is emerging as a threat, its epidemiology in our society remains largely unknown. LHPm1, the first P. mirabilis isolate harboring NDM-1, was detected from a companion dog that resides with a human owner. The whole-genome study revealed 20 different antimicrobial resistance (AMR) genes against various classes of antimicrobial agents, which corresponded to the MIC results. Genomic regions, including MDR genes, were identified with multiple variations and visualized in a comparative manner. In the whole-genome epidemiological analysis, multiple phylogroups were identified, revealing the genetic relationship of LHPm1 with other P. mirabilis strains carrying various AMR genes. These genetic findings offer comprehensive insights into NDM-1-producing P. mirabilis, underscoring the need for urgent control measures and surveillance programs using a "one health approach".

VesiX cetylpyridinium chloride is rapidly bactericidal and reduces uropathogenic Escherichia coli bladder epithelial cell invasion in vitro

Management of urinary tract infection (UTI) in postmenopausal women can be challenging. The recent rise in resistance to most of the available oral antibiotic options together with high recurrence rate in postmenopausal women has further complicated treatment of UTI. As such, intravesical instillations of antibiotics like gentamicin are being investigated as an alternative to oral antibiotic therapies. This study evaluates the efficacy of the candidate intravesical therapeutic VesiX, a solution containing the cationic detergent Cetylpyridinium chloride, against a broad range of uropathogenic bacterial species clinically isolated from postmenopausal women with recurrent UTI (rUTI). We also evaluate the cytotoxicity of VesiX against cultured bladder epithelial cells and find that low concentrations of 0.0063% and 0.0125% provide significant bactericidal effect toward diverse bacterial species including uropathogenic Escherichia coli (UPEC), Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, and Proteus mirabilis while minimizing cytotoxic effects against cultured 5637 bladder epithelial cells. Lastly, to begin to evaluate the potential utility of using VesiX in combination therapy with existing intravesical therapies for rUTI, we investigate the combined effects of VesiX and the intravesical antibiotic gentamicin. We find that VesiX and gentamicin are not antagonistic and are able to reduce levels of intracellular UPEC in cultured bladder epithelial cells.

IMPORTANCE

When urinary tract infections (UTIs), which affect over 50% of women, become resistant to available antibiotic therapies dangerous complications like kidney infection and lethal sepsis can occur. New therapeutic paradigms are needed to expand our arsenal against these difficult to manage infections. Our study investigates VesiX, a Cetylpyridinium chloride (CPC)-based therapeutic, as a candidate broad-spectrum antimicrobial agent for use in bladder instillation therapy for antibiotic-resistant UTI. CPC is a cationic surfactant that is FDA-approved for use in mouthwashes and is used as a food additive but has not been extensively evaluated as a UTI therapeutic. Our study is the first to investigate its rapid bactericidal kinetics against diverse uropathogenic bacterial species isolated from postmenopausal women with recurrent UTI and host cytotoxicity. We also report that together with the FDA-approved bladder-instillation agent gentamicin, VesiX was able to significantly reduce intracellular populations of uropathogenic bacteria in cultured bladder epithelial cells.

Mechanism of escape from the antibacterial activity of metal-based nanoparticles in clinically relevant bacteria: A systematic review

The emergency of antibiotic-resistant bacteria in severe infections is increasing, especially in nosocomial environments. The ESKAPE group is of special importance in the groups of multi-resistant bacteria due to its high capacity to generate resistance to antibiotics and bactericides. Therefore, metal-based nanomaterials are an attractive alternative to combat them because they have been demonstrated to damage biomolecules in the bacterial cells. However, there is a concern about bacteria developing resistance to NPs and their harmful effects due to environmental accumulation. Therefore, this systematic review aims to report the clinically relevant bacteria that have developed resistance to the NPs. According to the results of this systematic review, various mechanisms to counteract the antimicrobial activity of various NP types have been proposed. These mechanisms can be grouped into the following categories: production of extracellular compounds, metal efflux pumps, ROS response, genetic changes, DNA repair, adaptative morphogenesis, and changes in the plasma membrane.

Antigenic and Structural Properties of the Lipopolysaccharide of the Uropathogenic Proteus mirabilis Dm55 Strain Classified to a New O85 Proteus Serogroup

The aim of the study was the serological and structural characterization of the lipopolysaccharide (LPS) O antigen from P. mirabilis Dm55 coming from the urine of a patient from Lodz. The Dm55 LPS was recognized in ELISA only by the O54 antiserum, suggesting a serological distinction of the Dm55 O antigen from all the 84 Proteus LPS serotypes described. The obtained polyclonal rabbit serum against P. mirabilis Dm55 reacted in ELISA and Western blotting with a few LPSs (including O54), but the reactions were weaker than those observed in the homologous system. The LPS of P. mirabilis Dm55 was subjected to mild acid hydrolysis, and the obtained high-molecular-mass O polysaccharide was chemically studied using sugar and methylation analyses, mass spectrometry, and 1H and 13C NMR spectroscopy, including 1H,1H NOESY, and 1H,13C HMBC experiments. The Dm55 O unit is a branched three-saccharide, and its linear fragment contains α-GalpNAc and β-Galp, whereas α-GlcpNAc occupies a terminal position. The Dm55 OPS shares a disaccharide epitope with the Proteus O54 antigen. Due to the structural differences of the studied O antigen from the other described Proteus O polysaccharides, we propose to classify the P. mirabilis Dm55 strain to a new Proteus O85 serogroup.

A correlation study between virulence factors and multidrug resistance among clinical isolates of Proteus mirabilis

Treatment of Proteus mirabilis infections is a challenge due to the high abundance of virulence factors and the high intrinsic resistance to antimicrobials. Multidrug resistance (MDR) and extensive drug resistance (XDR) further challenge the control of P. mirabilis infection. This study aimed to investigate the correlation between virulence determinants and multidrug resistance in 100 clinical isolates of P. mirabilis collected in Alexandria from December 2019 to June 2021. Susceptibility to antimicrobials was tested by the Kirby Bauer method. Detection of swarming, urease, protease, hemolysin, and biofilm formation was performed phenotypically and by PCR amplification of zapA, flaA, ureC, mrpA, atfA, ucaA, hpmA, and luxS. MDR and XDR were detected in 34% and 5%, respectively. All isolates were positive for motility, swarming, urease, and protease production. Ninety percent were positive for hemolysin production, while 73% formed biofilm. All isolates possessed the ureC and zapA genes. The luxS, flaA, ucaA, hpmA, mrpA, and atfA genes were detected in 99%, 98%, 96% 90%, 89%, and 84%, respectively. The presence of a single biofilm-related gene was statistically correlated with non-biofilm production (P= 0.018). It was concluded that P. mirabilis isolates from catheterized-urine samples were significantly associated with biofilm formation. MDR and virulence were not statistically correlated. A significant positive correlation was detected between some virulence genes in P. mirabilis. Non-MDR isolates of P. mirabilis had a high abundance of virulence factors with no statistically significant difference from MDR. Most of the MDR and all XDR isolates could produce biofilm.

Virulence-related factors and antimicrobial resistance in Proteus mirabilis isolated from domestic and stray dogs

Introduction

Proteus mirabilis is a multi-host pathogen that causes diseases of varying severity in a wide range of mammals, including humans. Proteus mirabilis is resistant to multiple antibiotics and has acquired the ability to produce expanded spectrum of β-lactamases, leading to serious public health problems. However, the available information on P. mirabilis isolated from feces of dogs, is still poorly understood, as is the correlation between its virulence-associated genes (VAGs) and antibiotic resistance genes (ARGs).

Method

In this study, we isolated 75 strains of P. mirabilis from 241 samples, and investigated the swarming motility, biofilm formation, antimicrobial resistance (AMR), distribution of VAGs and ARGs, as well as the presence of class 1, 2, and 3 integrons in these isolates.

Results

Our findings suggest a high prevalence of intensive swarming motility and strong biofilm formation ability among P. mirabilis isolates. Isolates were primarily resistant to cefazolin (70.67%) and imipenem (70.67%). These isolates were found to carry ureC, FliL, ireA, zapA, ptA, hpmA, hpmB, pmfA, rsbA, mrpA, and ucaA with varying prevalence levels of 100.00, 100.00, 100.00, 98.67, 98.67, 90.67, 90.67, 90.67, 90.67, 89.33, and 70.67%, respectively. Additionally, the isolates were found to carry aac(6')-Ib, qnrD, floR, bla_CTX-M, bla_CTX-M-2, bla_OXA-1, bla_TEM, tetA, tetB and tetM with varying prevalence levels of 38.67, 32.00, 25.33, 17.33, 16.00, 10.67, 5.33, 2.67, 1.33, and 1.33%, respectively. Among 40 MDR strains, 14 (35.00%) were found to carry class 1 integrons, 12 (30.00%) strains carried class 2 integrons, while no class 3 integrons was detected. There was a significant positive correlation between the class 1 integrons and three ARGs: bla_TEM, bla_CTX-M, and bla_CTX-M-2. This study revealed that P. mirabilis strains isolated from domestic dogs exhibited a higher prevalence of MDR, and carried fewer VAGs but more ARGs compared to those isolated from stay dogs. Furthermore, a negative correlation was observed between VAGs and ARGs.

Discussion

Given the increasing antimicrobial resistance of P. mirabilis, veterinarians should adopt a prudent approach towards antibiotics administration in dogs to mitigate the emergence and dissemination of MDR strains that pose a potential threat to public health.

Structural and Serological Characterization of the O Antigen of Proteus mirabilis Clinical Isolates Classified into a New Proteus Serogroup, O84

Two closely related Proteus mirabilis smooth strains, Kr1 and Ks20, were isolated from wound and skin samples, respectively, of two infected patients in central Poland. Serological tests, using the rabbit Kr1-specific antiserum, revealed that both strains presented the same O serotype. Their O antigens are unique among the Proteus O serotypes, which had been described earlier, as they were not recognized in an enzyme-linked immunosorbent assay (ELISA) by a set of Proteus O1-O83 antisera. Additionally, the Kr1 antiserum did not react with O1-O83 lipopolysaccharides (LPSs). The O-specific polysaccharide (OPS, O antigen) of P. mirabilis Kr1 was obtained via the mild acid degradation of the LPSs, and its structure was established via a chemical analysis and one- and two-dimensional ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy applied to both initial and O-deacetylated polysaccharides, where most β-2-acetamido-2-deoxyglucose (N-acetylglucosamine) (GlcNAc) residues are non-stoichiometrically O-acetylated at positions 3, 4, and 6 or 3 and 6, and a minority of α-GlcNAc residues are 6-O-acetylated. Based on the serological features and chemical data, P. mirabilis Kr1 and Ks20 were proposed as candidates to a new successive O-serogroup in the genus Proteus, O84, which is another example of new Proteus O serotypes identified lately among serologically differentiated Proteus bacilli infecting patients in central Poland.

Virulence factors of uropathogens and their role in host pathogen interactions

Gram-positive and Gram-negative bacterial pathogens are commonly found in Urinary Tract Infection (UTI), particularly infected in females like pregnant women, elder people, sexually active, or individuals prone to other risk factors for UTI. In this article, we review the expression of virulence surface proteins and their interaction with host cells for the most frequently isolated uropathogens: Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Klebsiella pneumoniae, and Staphylococcus saprophyticus. In addition to the host cell interaction, surface protein regulation was also discussed in this article. The surface protein regulation serves as a key tool in differentiating the pathogen isotypes. Furthermore, it might provide insights on novel diagnostic methods to detect uropathogen that are otherwise easily overlooked due to limited culture-based assays. In essence, this review shall provide an in-depth understanding on secretion of virulence factors of various uropathogens and their role in host-pathogen interaction, this knowledge might be useful in the development of therapeutics against uropathogens.

Organic Acids Secreted by Lactobacillus spp. Isolated from Urine and Their Antimicrobial Activity against Uropathogenic Proteus mirabilis

The natural microbiota of the urinary tract includes Lactobacillus spp., which secrete molecules with antimicrobial properties and have antagonistic activity against many pathogens. This paper focuses on the antibacterial effect of Lactobacillus strains isolated from urine against clinical strains of Proteus mirabilis isolated from kidney stones and from urine with coexisting urolithiasis. The study involved analyzing the main antimicrobial molecules secreted by Lactobacillus. In order to indicate which agent had the strongest antimicrobial effect, the supernatants were made alkaline and treated with catalase and high temperature. Both treated and untreated supernatants were analyzed for their activity. Exposing uropathogens to all untreated cell-free supernatants of Lactobacillus significantly reduced their growth, and it was established that these properties were related to organic acid secretion by these strains. Using LC–MS/MS and spectrophotometric techniques, lactic, citric, and succinic acids were determined qualitatively and quantitatively. The influence of these acids on the P. mirabilis growth and biofilm formation and their influence on membrane permeability were also investigated. The results indicate that organic acids secreted by Lactobacillus strains have a high antibacterial potential and could be used as novel agents in the treatment of urinary tract infections caused by P. mirabilis.

Urinary Tract Infections in Pennsylvania Long-Term Care Facilities

Urinary tract infections (UTIs) are common healthcare-associated infections (HAIs) in older adults that live in long-term care (LTC) facilities. A query of the Pennsylvania Patient Safety Reporting System (PA-PSRS) found that symptomatic UTI (SUTI) and catheter-associated UTI (CAUTI) rates increased from 2016 and peaked in the second quarter of 2020. Although the number of urinary catheter days reported by LTC facilities has trended downward from 2016 to the beginning of 2020, the urinary catheter utilization rate increased slightly in the second quarter of 2020. We also examined various epidemiological factors. An average of 47.6% of SUTIs and 32.3% of CAUTIs were associated with E. coli from 2016 through 2020. However, the percentage of CAUTIs associated with E. coli decreased while the percentage of CAUTIs associated with organisms of the tribe Proteeae (Proteus, Providencia, and Morganella genera) increased from 2016 through 2020. Furthermore, the percentage of CAUTIs associated with carbapenem-resistant Enterobacterales (CRE) and organisms producing extended-spectrum beta-lactamases (ESBL) also increased, while the percentage of CAUTIs associated with vancomycin-resistant Enterococci (VRE) decreased from 2016 through 2020. An average of 38.5% of SUTIs and 41.5% of CAUTIs were reported to be treated with fluoroquinolones from 2016 through 2020. However, the percentage of both SUTIs and CAUTIs treated with fluoroquinolones decreased from 2016 through 2020, while an increasing percentage of both SUTIs and CAUTIs was reported to have been treated with cephalosporins and carbapenems from 2016 through 2020. Thus, to further promote resident safety, we use these epidemiological trends to better understand current risks for residents and to further guide development of best practices for prevention, identification, and treatment of UTIs as well as to further advance antibiotic stewardship practices.

Effective Antimicrobial Solutions for Eradicating Multi-Resistant and β-Lactamase-Producing Nosocomial Gram-Negative Pathogens

Antimicrobial resistance (AMR) remains one of the greatest public health-perturbing crises of the 21st century, where species have evolved a myriad of defence strategies to resist conventional therapy. The production of extended-spectrum β-lactamase (ESBL), AmpC and carbapenemases in Gram-negative bacteria (GNB) is one such mechanism that currently poses a significant threat to the continuity of first-line and last-line β-lactam agents, where multi-drug-resistant GNB currently warrant a pandemic on their own merit. The World Health Organisation (WHO) has long recognised the need for an improved and coordinated global effort to contain these pathogens, where two factors in particular, international travel and exposure to antimicrobials, play an important role in the emergence and dissemination of antibiotic-resistant genes. Studies described herein assess the resistance patterns of isolated nosocomial pathogens, where levels of resistance were detected using recognised in vitro methods. Additionally, studies conducted extensively investigated alternative biocide (namely peracetic acid, triameen and benzalkonium chloride) and therapeutic options (specifically 1,10-phenanthroline-5,6-dione), where the levels of induced endotoxin from E. coli were also studied for the latter. Antibiotic susceptibility testing revealed there was a significant association between multi-drug resistance and ESBL production, where the WHO critical-priority pathogens, namely E. coli, K. pneumoniae, A. baumannii and P. aeruginosa, exhibited among the greatest levels of multi-drug resistance. Novel compound 1,10-phenanthroline-5,6-dione (phendione) shows promising antimicrobial activity, with MICs determined for all bacterial species, where levels of induced endotoxin varied depending on the concentration used. Tested biocide agents show potential to act as intermediate-level disinfectants in hospital settings, where all tested clinical isolates were susceptible to treatment.

atpD gene sequencing, multidrug resistance traits, virulence-determinants, and antimicrobial resistance genes of emerging XDR and MDR-Proteus mirabilis

Proteus mirabilis is a common opportunistic pathogen causing severe illness in humans and animals. To determine the prevalence, antibiogram, biofilm-formation, screening of virulence, and antimicrobial resistance genes in P. mirabilis isolates from ducks; 240 samples were obtained from apparently healthy and diseased ducks from private farms in Port-Said Province, Egypt. The collected samples were examined bacteriologically, and then the recovered isolates were tested for atpD gene sequencing, antimicrobial susceptibility, biofilm-formation, PCR detection of virulence, and antimicrobial resistance genes. The prevalence of P. mirabilis in the examined samples was 14.6% (35/240). The identification of the recovered isolates was confirmed by the atpD gene sequencing, where the tested isolates shared a common ancestor. Besides, 94.3% of P. mirabilis isolates were biofilm producers. The recovered isolates were resistant to penicillins, sulfonamides, β-Lactam-β-lactamase-inhibitor-combinations, tetracyclines, cephalosporins, macrolides, and quinolones. Using PCR, the retrieved strains harbored atpD, ureC, rsbA, and zapA virulence genes with a prevalence of 100%, 100%, 94.3%, and 91.4%, respectively. Moreover, 31.4% (11/35) of the recovered strains were XDR to 8 antimicrobial classes that harbored bla_TEM, bla_OXA-1, bla_CTX-M, tetA, and sul1 genes. Besides, 22.8% (8/35) of the tested strains were MDR to 3 antimicrobial classes and possessed bla_TEM, tetA, and sul1genes. Furthermore, 17.1% (6/35) of the tested strains were MDR to 7 antimicrobial classes and harbored bla_TEM, bla_OXA-1, bla_CTX-M, tetA, and sul1 genes. Alarmingly, three strains were carbapenem-resistant that exhibited PDR to all the tested 10 antimicrobial classes and shared bla_TEM, bla_OXA-1, bla_CTX-M, tetA, and sul1 genes. Of them, two strains harbored the bla_NDM-1 gene, and one strain carried the bla_KPC gene. In brief, to the best of our knowledge, this is the first study demonstrating the emergence of XDR and MDR-P.mirabilis in ducks. Norfloxacin exhibited promising antibacterial activity against the recovered XDR and MDR-P. mirabilis. The emergence of PDR, XDR, and MDR-strains constitutes a threat alarm that indicates the complicated treatment of the infections caused by these superbugs.