Development of a Novel Targeting System for Lethal Photosensitization of Antibiotic-Resistant Strains of Staphylococcus aureus

ABSTRACT Light-activated antimicrobial agents (photosensitizers) are promising alternatives to antibiotics for the treatment of topical infections. To improve efficacy and avoid possible damage to host tissues, targeting of the photosensitizer to the infecting organism is desirable, and this has previously been achieved using antibodies and chemical modification of the agent. In this study we investigated the possibility of using a bacteriophage to deliver the photosensitizer tin(IV) chlorin e6 (SnCe6) to Staphylococcus aureus. SnCe6 was covalently linked to S. aureus bacteriophage 75, and the ability of the conjugate to kill various strains of S. aureus when exposed to red light was determined. Substantial kills of methicillin- and vancomycin-intermediate strains of S. aureus were achieved using low concentrations of the conjugate (containing 1.5 μg/ml SnCe6) and low light doses (21 J/cm2). Under these conditions, the viability of human epithelial cells (in the absence of bacteria) was largely unaffected. On a molar equivalent basis, the conjugate was a more effective bactericide than the unconjugated SnCe6, and killing was not growth phase dependent. The conjugate was effective against vancomycin-intermediate strains of S. aureus even after growth in vancomycin. The results of this study have demonstrated that a bacteriophage can be used to deliver a photosensitizer to a target organism, resulting in enhanced and selective killing of the organism. Such attributes are desirable in an agent to be used in the photodynamic therapy of infectious diseases.

Download Full-text

Antibacterial Peptides Resistance in Staphylococcus aureus: Various Mechanisms and the Association with Pathogenicity

Genes ◽

10.3390/genes12101527 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1527

Author(s):

Miki Kawada-Matsuo ◽

Mi Nguyen-Tra Le ◽

Hitoshi Komatsuzawa

Keyword(s):

Staphylococcus Aureus ◽

Antimicrobial Peptides ◽

Antibacterial Peptides ◽

Low Concentrations ◽

Component Systems ◽

Two Component Systems ◽

Resistant Strains ◽

Resistant Mutants ◽

High Concentrations

Staphylococcus aureus is a bacterium that mainly colonizes the nasal cavity and skin. To colonize the host, it is necessary for S. aureus to resist many antibacterial factors derived from human and commensal bacteria. Among them are the bacteria-derived antimicrobial peptides (AMPs) called bacteriocins. It was reported that some two-component systems (TCSs), which are signal transduction systems specific to bacteria, are involved in the resistance to several bacteriocins in S. aureus. However, the TCS-mediated resistance is limited to relatively low concentrations of bacteriocins, while high concentrations of bacteriocins still exhibit antibacterial activity against S. aureus. To determine whether we could obtain highly bacteriocin-resistant mutants, we tried to isolate highly nisin A-resistant mutants by exposing the cells to sub-minimum inhibitory concentrations (MICs) of nisin A. Nisin A is one of the bacteriocins produced by Lactococcus lactis and is utilized as a food preservative worldwide. Finally, we obtained highly nisin A-resistant mutants with mutations in one TCS, BraRS, and in PmtR, which is involved in the expression of pmtABCD. Notably, some highly resistant strains also showed increased pathogenicity. Based on our findings, this review provides up-to-date information on the role of TCSs in the susceptibility to antibacterial peptides. Additionally, the mechanism for high antimicrobial peptides resistance and its association with pathogenicity in S. aureus is elucidated.

Download Full-text

AN IMPLICATION OF ACTINOMYCETES ON HUMAN WELL-BEING: A REVIEW

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2019v11i5.31829 ◽

2019 ◽

pp. 11-18

Author(s):

ALI MOHAMMED ABDULLAH BAWAZIR ◽

PALAKSHA ◽

MANJULA SHANTARAM ◽

MANJULA SHANTARAM

Keyword(s):

Antimicrobial Resistance ◽

Secondary Metabolites ◽

Human Health ◽

Antimicrobial Agents ◽

Well Being ◽

Pathogenic Microorganisms ◽

Antibiotic Resistant ◽

Bioactive Secondary Metabolites ◽

Resistant Strains ◽

All Diseases

This review conceptualizes about the actinomycetes and its contribution to human health by playing a key role as bioactive secondary metabolites, such as enzymes, antibiotics and pigments, leading to their diverse applications and use in various industries. These searches have been uncommonly successful, and around 66% of naturally happening antibiotics, including many medically important, have been isolated from actinomycetes. The speedy occurrence of antimicrobial resistance among pathogens has led to a renewed interest to search for novel antimicrobial agents, but these antibiotics are not enough for the treatment of all diseases because there is a berserk requirement for a novel actinomycetes to combat against the antibiotic-resistant strains of pathogenic microorganisms, which are quickly expanding bit by bit. Actinomycetes are the important providers to the pharmaceutical and other industries and are well known for their capacity to produce secondary metabolites many of which are active against pathogenic microorganisms.

Download Full-text

Antibiotic resistant staphylococci acquired during the first year of life

Journal of Hygiene ◽

10.1017/s0022172400053821 ◽

1978 ◽

Vol 81 (1) ◽

pp. 125-130 ◽

Cited By ~ 7

Author(s):

M. L. Burr ◽

C. H. L. Howells ◽

P. W. J. Rees

Keyword(s):

Staphylococcus Aureus ◽

Antibiotic Treatment ◽

First Year ◽

Antibiotic Resistant ◽

South Wales ◽

Maternity Hospitals ◽

Nasal Swabs ◽

Resistant Strains ◽

Discharge From Hospital ◽

First Year Of Life

SUMMARYNasal swabs were taken from 492 babies born consecutively to residents of two South Wales towns soon after their discharge from maternity hospitals. Staphylococcus aureus was isolated from 352 babies (72%) and in 79 (22%) of these it was resistant to at least one antibiotic. By the time these babies were a year old the prevalence of both sensitive and resistant strains had fallen, so that only 12% still carried nasal staphylococci, but 64% of these organisms were then resistant to penicillin. Administration of penicillin to the baby seemed to be a more important factor in selecting resistant organisms than other antibiotics given to the baby, any antibiotic treatment to other members of the household, or discharge from hospital.

Download Full-text

Strain diversity and antibiotic-sensitivity of staphylococcus spp. Isolates from patients of multiprofile pediatric hospital in St. Petersburg, Russia

Pediatrician (St Petersburg) ◽

10.17816/ped12415-25 ◽

2021 ◽

Vol 12 (4) ◽

pp. 15-25

Author(s):

D. P. Gladin ◽

A. R. Khairullina ◽

A. M. Korolyuk ◽

N. S. Kozlova ◽

O. V. Ananyeva ◽

...

Keyword(s):

Antimicrobial Agents ◽

Antibiotic Sensitivity ◽

Specific Weight ◽

Multidrug Resistant ◽

Diffusion Method ◽

Therapeutic Effects ◽

Antimicrobial Drugs ◽

Antibiotic Resistant ◽

Resistant Strains ◽

Staphylococcus Spp

Background. Staphylocci are the leading pus-forming Gram-positive bacteria in the childrens hospitals. The prevalence of the antibiotic resistant strains among them limits therapeutic effects of infections in children. Aim. The research is aimed at characterizing the species of staphylococcus, which are isolated from the different clinical specimens of the patients at the clinics of Saint Petersburg State Pediatric Medical University in 2019, and analysis of their susceptibility to antimicrobial agents. Materials and metods. According to the clinical recommendations of 2018, susceptibility to antimicrobial drugs (AMD) was revealed in 860 strains of staphylococci determined by the disc diffusion method, which were identified by the automated analyser Vitek-2 compact. Results. Six species of staphylococci were represented at the hospital departments, among which Staphylococcus epidermidis prevailed in the departments of the neonate pathology department and intensive care units (63.0% and 46.2% respectively), Staphylococcus aureus is commonly found at the departments of surgery and the departments of the therapeutic profiles (61.7% and 46.2% respectively). More than a half of the staphylococci strains (63.0%) were resistant to at least one of the antimicrobial drugs. Vancomycin and line solid showed the highest activity to these staphylococci. High specific weight of multidrug resistant (MDR) bacteria (37.8%) and extensively drug resistant (XDR) strains of the phenotype (33.0%) was revealed. The level of antibiotic resistant strains was the highest in Staphylococcus haemolyticus (98.1%) and S. epidermidis (82.0%), while the specific weight of the resistant ones, MDR and XDR strains was extremely low among S. aureus (16.2%, 1.5% and 0.4 respectively), as well as in methicillin-resistant isolates (0.8%). Conclusions. A great variety of antibiotic resistance was revealed among the staphylococci. The prevalence of these strains in the pediatric hospitals requires constant local monitoring of the antibiotic resistant staphylococci.

Download Full-text

Staphylococcus aureus Tolerance and Genomic Response to Photodynamic Inactivation

mSphere ◽

10.1128/msphere.00762-20 ◽

2021 ◽

Vol 6 (1) ◽

Cited By ~ 1

Author(s):

Sara B. Snell ◽

Ann Lindley Gill ◽

Constantine G. Haidaris ◽

Thomas H. Foster ◽

Timothy M. Baran ◽

...

Keyword(s):

Staphylococcus Aureus ◽

High Mortality ◽

Cellular Response ◽

Mortality Rates ◽

Adjunctive Treatment ◽

Photodynamic Inactivation ◽

Antibiotic Resistant ◽

Promising Alternative ◽

Content Type ◽

Resistant Strains

ABSTRACT Staphylococcus aureus is an opportunistic pathogen with a clinical spectrum ranging from asymptomatic skin colonization to invasive infections. While traditional antibiotic therapies can be effective against S. aureus, the increasing prevalence of antibiotic-resistant strains results in treatment failures and high mortality rates. Photodynamic inactivation (PDI) is an innovative and promising alternative to antibiotics. While progress has been made in our understanding of the bacterial response to PDI, major gaps remain in our knowledge of PDI tolerance, the global cellular response, and adaptive genomic mutations acquired as a result of PDI. To address these gaps, S. aureus HG003 and isogenic mutants with mutations in agr, mutS, mutL, and mutY exposed to single or multiple doses of PDI were assessed for survival and tolerance and examined by global transcriptome and genome analyses to identify regulatory and genetic adaptations that contribute to tolerance. Pathways in inorganic ion transport, oxidative response, DNA replication recombination and repair, and cell wall and membrane biogenesis were identified in a global cellular response to PDI. Tolerance to PDI was associated with superoxide dismutase and the S. aureus global methylhydroquinone (MHQ)-quinone transcriptome network. Genome analysis of PDI-tolerant HG003 identified a nonsynonymous mutation in the quinone binding domain of the transcriptional repressor QsrR, which mediates quinone sensing and oxidant response. Acquisition of a heritable QsrR mutation through repeated PDI treatment demonstrates selective adaption of S. aureus to PDI. PDI tolerance of a qsrR gene deletion in HG003 confirmed that QsrR regulates the S. aureus response to PDI. IMPORTANCE Staphylococcus aureus can cause disease at most body sites, with illness ranging from asymptomatic infection to death. The increasing prevalence of antibiotic-resistant strains results in treatment failures and high mortality rates. S. aureus acquires resistance to antibiotics through multiple mechanisms, often by genetic variation that alters antimicrobial targets. Photodynamic inactivation (PDI), which employs a combination of a nontoxic dye and low-intensity visible light, is a promising alternative to antibiotics that effectively eradicates S. aureus in human infections when antibiotics are no longer effective. In this study, we demonstrate that repeated exposure to PDI results in resistance of S. aureus to further PDI treatment and identify the underlying bacterial mechanisms that contribute to resistance. This work supports further analysis of these mechanisms and refinement of this novel technology as an adjunctive treatment for S. aureus infections.

Download Full-text

The Neutrally Charged Diarylurea Compound PQ401 Kills Antibiotic-Resistant and Antibiotic-Tolerant Staphylococcus aureus

mBio ◽

10.1128/mbio.01140-20 ◽

2020 ◽

Vol 11 (3) ◽

Cited By ~ 4

Author(s):

Wooseong Kim ◽

Guijin Zou ◽

Wen Pan ◽

Nico Fricke ◽

Hammad A. Faizi ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Lipid Bilayers ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Cross Resistance ◽

Lead Compound ◽

Neutral Form ◽

Cationic Form ◽

Antibiotic Resistant ◽

Content Type

ABSTRACT Resistance or tolerance to traditional antibiotics is a challenging issue in antimicrobial chemotherapy. Moreover, traditional bactericidal antibiotics kill only actively growing bacterial cells, whereas nongrowing metabolically inactive cells are tolerant to and therefore “persist” in the presence of legacy antibiotics. Here, we report that the diarylurea derivative PQ401, previously characterized as an inhibitor of the insulin-like growth factor I receptor, kills both antibiotic-resistant and nongrowing antibiotic-tolerant methicillin-resistant Staphylococcus aureus (MRSA) by lipid bilayer disruption. PQ401 showed several beneficial properties as an antimicrobial lead compound, including rapid killing kinetics, low probability for resistance development, high selectivity to bacterial membranes compared to mammalian membranes, and synergism with gentamicin. In contrast to well-studied membrane-disrupting cationic antimicrobial low-molecular-weight compounds and peptides, molecular dynamic simulations supported by efficacy data demonstrate that the neutral form of PQ401 penetrates and subsequently embeds into bacterial lipid bilayers more effectively than the cationic form. Lastly, PQ401 showed efficacy in both the Caenorhabditis elegans and Galleria mellonella models of MRSA infection. These data suggest that PQ401 may be a lead candidate for repurposing as a membrane-active antimicrobial and has potential for further development as a human antibacterial therapeutic for difficult-to-treat infections caused by both drug-resistant and -tolerant S. aureus. IMPORTANCE Membrane-damaging antimicrobial agents have great potential to treat multidrug-resistant or multidrug-tolerant bacteria against which conventional antibiotics are not effective. However, their therapeutic applications are often hampered due to their low selectivity to bacterial over mammalian membranes or their potential for cross-resistance to a broad spectrum of cationic membrane-active antimicrobial agents. We discovered that the diarylurea derivative compound PQ401 has antimicrobial potency against multidrug-resistant and multidrug-tolerant Staphylococcus aureus. PQ401 selectively disrupts bacterial membrane lipid bilayers in comparison to mammalian membranes. Unlike cationic membrane-active antimicrobials, the neutral form of PQ401 rather than its cationic form exhibits maximum membrane activity. Overall, our results demonstrate that PQ401 could be a promising lead compound that overcomes the current limitations of membrane selectivity and cross-resistance. Also, this work provides deeper insight into the design and development of new noncharged membrane-targeting therapeutics to combat hard-to-cure bacterial infections.

Download Full-text

Design, Overproduction and Purification of the Chimeric Phage Lysin MLTphg Fighting against Staphylococcus aureus

Processes ◽

10.3390/pr8121587 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1587

Author(s):

Feng Wang ◽

Xiaohang Liu ◽

Zhengyu Deng ◽

Yao Zhang ◽

Xinyu Ji ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Bacterial Infections ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Antibiotic Resistant ◽

E Coli ◽

Conventional Antibiotics ◽

Phage Lysin ◽

Shed Light

With the increasing spread of multidrug-resistant bacterial pathogens, it is of great importance to develop alternatives to conventional antibiotics. Here, we report the generation of a chimeric phage lysin, MLTphg, which was assembled by joining the lysins derived from Meiothermus bacteriophage MMP7 and Thermus bacteriophage TSP4 with a flexible linker via chimeolysin engineering. As a potential antimicrobial agent, MLTphg can be obtained by overproduction in Escherichia coli BL21(DE3) cells and the following Ni-affinity chromatography. Finally, we recovered about 40 ± 1.9 mg of MLTphg from 1 L of the host E. coli BL21(DE3) culture. The purified MLTphg showed peak activity against Staphylococcus aureus ATCC6538 between 35 and 40 °C, and maintained approximately 44.5 ± 2.1% activity at room temperature (25 °C). Moreover, as a produced chimera, it exhibited considerably improved bactericidal activity against Staphylococcus aureus (2.9 ± 0.1 log10 reduction was observed upon 40 nM MLTphg treatment at 37 °C for 30 min) and also a group of antibiotic-resistant bacteria compared to its parental lysins, TSPphg and MMPphg. In the current age of growing antibiotic resistance, our results provide an engineering basis for developing phage lysins as novel antimicrobial agents and shed light on bacteriophage-based strategies to tackle bacterial infections.

Download Full-text

Canadian national survey of prevalence of antimicrobial resistance among clinical isolates of Streptococcus pneumoniae. Canadian Bacterial Surveillance Network.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.40.9.2190 ◽

1996 ◽

Vol 40 (9) ◽

pp. 2190-2193 ◽

Cited By ~ 49

Author(s):

A E Simor ◽

M Louie ◽

D E Low

Keyword(s):

Streptococcus Pneumoniae ◽

Antimicrobial Agents ◽

Clinical Isolates ◽

Beta Lactam ◽

Surveillance Network ◽

Antibiotic Resistant ◽

Intermediate Resistance ◽

Resistant Strains ◽

High Level ◽

Level Resistance

The antimicrobial susceptibilities of 1,089 clinical isolates of Streptococcus pneumoniae obtained from 39 laboratories across Canada between October 1994 and August 1995 were determined. A total of 91 isolates (8.4%) demonstrated intermediate resistance (MIC, 0.1 to 1.0 microgram/ml) and 36 (3.3%) had high-level resistance (MIC, > or = 2.0 micrograms/ml) to penicillin. Penicillin-resistant strains were more likely to have been recovered from normally sterile sites (P = 0.005) and to be cross-resistant to several beta-lactam and non-beta-lactam antimicrobial agents (P < 0.05). These results indicate that there has been a recent significant increase in the prevalence of antibiotic-resistant S. pneumoniae in Canada.

Download Full-text