scholarly journals Effect of Photodynamic Antibacterial Chemotherapy Combined with Antibiotics on Gram-Positive and Gram-Negative Bacteria

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3152 ◽  
Author(s):  
Yana Ilizirov ◽  
Andrei Formanovsky ◽  
Irina Mikhura ◽  
Yossi Paitan ◽  
Faina Nakonechny ◽  
...  
Keyword(s):  
Rose Bengal ◽  
Bacterial Resistance ◽  
Antibiotic Sensitivity ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Inappropriate Use ◽  
Resistant Strains ◽  
Antibacterial Chemotherapy ◽  
Mrsa Strains

The well-known and rapidly growing phenomenon of bacterial resistance to antibiotics is caused by uncontrolled, excessive and inappropriate use of antibiotics. One of alternatives to antibiotics is Photodynamic Antibacterial Chemotherapy (PACT). In the present study, the effect of PACT using a photosensitizer Rose Bengal alone and in combination with antibiotics including methicillin and derivatives of sulfanilamide synthesized by us was tested against antibiotic-sensitive and antibiotic-resistant clinical isolates of Gram-positive S. aureus and Gram-negative P. aeruginosa. Antibiotic-sensitive and resistant strains of P. aeruginosa were eradicated by Rose Bengal under illumination and by sulfanilamide but were not inhibited by new sulfanilamide derivatives. No increase in sensitivity of P. aeruginosa cells to sulfanilamide was observed upon a combination of Rose Bengal and sulfanilamide under illumination. All tested S. aureus strains (MSSA and MRSA) were effectively inhibited by PACT. When treated with sub-MIC concentrations of Rose Bengal under illumination, the minimum inhibitory concentrations (MIC) of methicillin decreased significantly for MSSA and MRSA strains. In some cases, antibiotic sensitivity of resistant strains can be restored by combining antibiotics with PACT.

Monitoring of the leading causative agents of osteomyelitis and their antibiotic resistance

2020 ◽  
Vol 65 (9) ◽  
pp. 562-566
Author(s):  
I. V. Shipitsyna ◽  
E. V. Osipova ◽  
O. A. Astashova ◽  
D. S. Leonchuk
Keyword(s):  
Antibiotic Resistance ◽  
Species Composition ◽  
Antibiotic Sensitivity ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Methicillin Resistant ◽  
Causative Agents ◽  
Resistant Strains ◽  
Bacterial Associations

The annual monitoring of the species composition of the causative agents of osteomyelitis, the identification of antibiotic-resistant strains, the study of the species composition of associations of microorganisms, their adhesive activity will prevent the spread of infection. Analyze the spectrum of the leading causative agents of osteomyelitis, their antibiotic sensitivity, and also the adhesive activity of the identified bacterial associations. A microbiological analysis of 2197 smears of adult patients with various etiological forms of osteomyelitis who were treated in the departments of the purulent center of the FSBI «NMRCTO» of the RF Ministry of Health in 2019. The spectrum of pathogenic microflora, sensitivity to standard antibacterial drugs used in the clinic was studied. The biofilm-forming ability of associations of microorganisms was investigated. According to the conducted microbiological monitoring for 2019, the microflora spectrum for osteomyelitis is diverse, the main pathogens are S. aureus, S. epidermidis, P. aeruginosa, K. pneumoniae, Enterococcus sp. A high percentage of isolation of microbial associations was noted, most often mix cultures of gram-positive and gram-negative bacteria. Bacterial associations: S. aureus + P. aeruginosa, S. aureus + S. marcescens, S. aureus + A. baumannii, S. epidermidis + E. cloacae - actively formed a biofilm on the surface of polystyrene plates, and the adhesive potential depended on interstrain relations in the composition of the formed biofilm. Among Gram-negative microflora, multiresistant strains prevail, among Gram-positive microflora - a high percentage of methicillin-resistant Staphylococci. When analyzing the antibiotic sensitivity of the isolated microorganisms, a high percentage of resistant strains is noted. So, with respect to enterobacteria, β-lactam antibiotics, drugs from the group of aminoglycosides, turned out to be ineffective. Among non-fermenting gram-negative bacteria, A. baumannii strains had multiple antimicrobial resistance. Among gram-positive microorganisms, a high percentage of isolation of methicillin-resistant staphylococci was noted. The specificity of the course of the disease and measures aimed at eliminating the pathogen depend on the species composition in the focus of infection. The study of the etiological structure of osteomyelitis, the monitoring of the antibiotic resistance of pathogens and their persistent potential, makes it possible to adopt sound tactics of conservative and surgical treatment.

scholarly journals In Vitro and In Vivo Antibacterial Activities of Heteroaryl Isothiazolones against Resistant Gram-Positive Pathogens

2007 ◽  
Vol 51 (4) ◽  
pp. 1259-1267 ◽  
Author(s):  
Michael J. Pucci ◽  
Jijun Cheng ◽  
Steven D. Podos ◽  
Christy L. Thoma ◽  
Jane A. Thanassi ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Standard Dose ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Mrsa Strains ◽  
Time Kill

ABSTRACT The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10× MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were ≤1 mg/kg of body weight against S. aureus in the sepsis model, while decreases in the numbers of CFU per thigh equal to or greater than those detected in animals treated with a standard dose of vancomycin were seen in the animals with thigh infections. Pharmacokinetic analyses of treated mice indicated exposures similar to those to ciprofloxacin at equivalent dose levels. These promising initial data suggest further study on the use of the HITZs as antibacterial agents.

Bacterial resistance to disinfectants

2002 ◽  
Vol 3 (3) ◽  
pp. 22-24 ◽  
Author(s):  
AD Russell
Keyword(s):  
Bacterial Resistance ◽  
Organic Soil ◽  
Bacterial Spores ◽  
Gram Negative Bacteria ◽  
Mycobacterium Chelonae ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Gram Positive Cocci

A ntiseptics and disinfectants (biocides) are widely employed in controlling hospital infection. Their activity depends upon several factors, notably concentration, period of contract, pH, temperature, the type, nature and numbers of microorganisms to be inactivated and the presence of organic soil or other interfering material. Bacteria vary considerably in their response to antiseptics and disinfectants. Bacterial spores are the least susceptible, followed by mycobacteria (including glutaraldehyde-resistant Mycobacterium chelonae) and then by Gram-negative bacteria, notably pseudomonads. Gram-positive cocci, including antibiotic-resistant staphylococci, are readily inactivated by disinfectants. Enterococci, including vancomycin-resistant strains, are also susceptible but somewhat less so than staphylococci. Resistance is often intrinsic in nature, but may be acquired either by mutation or by the acquisition of genetic elements. Disinfectant rotation is practised in several hospitals but the issue remains contentious, although hospital isolates are often more resistant to biocides than laboratory or ‘standard’ strains.

scholarly journals Novel Broad-Spectrum Bis-(Imidazolinylindole) Derivatives with Potent Antibacterial Activities against Antibiotic-Resistant Strains

2009 ◽  
Vol 53 (10) ◽  
pp. 4283-4291 ◽  
Author(s):  
Rekha G. Panchal ◽  
Ricky L. Ulrich ◽  
Douglas Lane ◽  
Michelle M. Butler ◽  
Chad Houseweart ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
In Vivo Studies ◽  
Structural Variations ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Resistant Strains

ABSTRACT Given the limited number of structural classes of clinically available antimicrobial drugs, the discovery of antibacterials with novel chemical scaffolds is an important strategy in the development of effective therapeutics for both naturally occurring and engineered resistant strains of pathogenic bacteria. In this study, several diarylamidine derivatives were evaluated for their ability to protect macrophages from cell death following infection with Bacillus anthracis, a gram-positive spore-forming bacterium. Four bis-(imidazolinylindole) compounds were identified with potent antibacterial activity as measured by the protection of macrophages and by the inhibition of bacterial growth in vitro. These compounds were effective against a broad range of gram-positive and gram-negative bacterial species, including several antibiotic-resistant strains. Minor structural variations among the four compounds correlated with differences in their effects on bacterial macromolecular synthesis and mechanisms of resistance. In vivo studies revealed protection by two of the compounds of mice lethally infected with B. anthracis, Staphylococcus aureus, or Yersinia pestis. Taken together, these results indicate that the bis-(imidazolinylindole) compounds represent a new chemotype for the development of therapeutics for both gram-positive and gram-negative bacterial species as well as against antibiotic-resistant infections.

scholarly journals Decreased susceptibility to tigecycline inEscherichia colimediated by a mutation inmlaA

2016 ◽  
pp. AAC.01603-16
Author(s):  
Fang He ◽  
Juan Xu ◽  
Jianfeng Wang ◽  
Qiong Chen ◽  
Xiaoting Hua ◽  
...  
Keyword(s):  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Carbapenem Resistant ◽  
Resistant Strains ◽  
Carbapenem Resistant Enterobacteriaceae

Tigecycline, a type of glycylcycline, is a novel expanded-spectrum antibiotic that active against most Gram-negative and Gram-positive bacteria, including antibiotic-resistant strains such as carbapenem-resistant Enterobacteriaceae (1-3).…

scholarly journals Screening of an FDA-Approved Library for Novel Drugs against Y. pestis

Antibiotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
David Gur ◽  
Theodor Chitlaru ◽  
Emanuelle Mamroud ◽  
Ayelet Zauberman
Keyword(s):  
Drug Repurposing ◽  
Mortality Rates ◽  
Systematic Screening ◽  
Antibiotic Resistant ◽  
Gram Negative ◽  
Therapy Initiation ◽  
Novel Drugs ◽  
Resistant Strains ◽  
Approved Drugs ◽  
Fda Approved Drugs

Yersinia pestis is a Gram-negative pathogen that causes plague, a devastating disease that kills millions worldwide. Although plague is efficiently treatable by recommended antibiotics, the time of antibiotic therapy initiation is critical, as high mortality rates have been observed if treatment is delayed for longer than 24 h after symptom onset. To overcome the emergence of antibiotic resistant strains, we attempted a systematic screening of Food and Drug Administration (FDA)-approved drugs to identify alternative compounds which may possess antibacterial activity against Y. pestis. Here, we describe a drug-repurposing approach, which led to the identification of two antibiotic-like activities of the anticancer drugs bleomycin sulfate and streptozocin that have the potential for designing novel antiplague therapy approaches. The inhibitory characteristics of these two drugs were further addressed as well as their efficiency in affecting the growth of Y. pestis strains resistant to doxycycline and ciprofloxacin, antibiotics recommended for plague treatment.

AEROBIC BACTERIOLOGICAL PROFILE WITH ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF PUS SAMPLES AT A TERTIARY CARE HOSPITAL IN JAIPUR

2021 ◽  
pp. 65-67
Author(s):  
Hemendra K Sharma ◽  
Niketa Gupta ◽  
Mahesh Yadav ◽  
Aruna Vyas ◽  
Rajni Sharma
Keyword(s):  
Antimicrobial Susceptibility ◽  
Tertiary Care ◽  
Morbidity And Mortality ◽  
Diffusion Method ◽  
Care Hospital ◽  
Susceptibility Pattern ◽  
Gram Positive ◽  
Gram Negative ◽  
Inappropriate Use ◽  
Antimicrobial Susceptibility Pattern

Background: Pyogenic infections can be caused by various microorganisms and may co-exist as poly microbial infections which require antibiotic therapy. The inappropriate use of antibiotics has led to major problems of MDRO's contributing to morbidity and mortality. Even though the bacteriological prole of pus samples in many studies remain the same, antimicrobial susceptibility pattern of these isolates has shown a lot of variation. This study was conducted to assess bacteriological prole of pus samples and their antimicrobial susceptibility pattern Materials and Methods:Aretrospective study was carried out from April to June 2021. 540 pus culture aerobic bacterial isolates were included. The samples were cultured on Blood and MacConkey agar. After aerobic incubation at 37oC for 18-24 hrs, organisms were identied by conventional bacteriology methods as per laboratory protocol and antimicrobial susceptibility was tested by Kirby Bauer disc diffusion method as per CLSI 2020 guideline. Results: Out of 540 pus isolates , 452(83.7%)were gram negative bacili and 88(16.3%) were gram positive cocci Pseudomonas spp. 173(31.9%), was most common gram negative isolate while S.. aureus 66(12.19%) was most common Gram positive isolate. Most of gram negative isolates were susceptible to Imipenem and Polymyxin and gram positive isolates to vancomycin and linezolid . Conclusion: To combat resistance irrational use of antibiotics should be avoided. Also regular surveillance helps in implementing better therapeutic strategies to reduce morbidity and mortality

scholarly journals Neonatal septicemia and current scenario of antibiotic sensitivity pattern – A study of blood culture isolates in a tertiary care hospital, Rajkot

2021 ◽  
Vol 7 (4) ◽  
pp. 222-226
Author(s):  
Madhulika Mistry ◽  
Arpita Bhattacharya ◽  
Twinkle Kumar Parmar
Keyword(s):  
Neonatal Sepsis ◽  
Antibiotic Susceptibility ◽  
Antibiotic Sensitivity ◽  
Diffusion Method ◽  
Susceptibility Pattern ◽  
Gram Positive ◽  
Antibiotic Susceptibility Pattern ◽  
Neonatal Septicemia ◽  
Gram Negative ◽  
Current Scenario

Neonatal sepsis is one of the leading causes of neonatal mortality in developing countries. Neonatal sepsis can be classified into two subtypes depending upon onset of symptoms- before 72 hours of life (early-onset neonatal sepsis—EONS) or later (late-onset neonatal sepsis—LONS). Bacteriological profile and antibiotic susceptibility pattern in neonatal septicemia are changing time-to-time and place-to-place. This study is aimed to know the current scenario of neonatal septicemia and antibiotic susceptibility pattern for determining effective treatment, hence reducing burden of antibiotic resistance.This is a Retrospective study. Data was collected from Bacteriology lab, PDUMC Rajkot (May 2020 – May 2021). Blood cultures were performed on suspected neonates. Both BACTEC and conventional methods were used. Organisms were isolated by standard microbiological protocols and antibiotic sensitivity was performed by Kirby-Bauer disc diffusion method as per CLSI- 2020/2021 guidelines. Total 1402 samples were screened. 326 were positive (23.25%). 214(65.64%) were male and 112(34.36%) were female. CONS (32.21%) was found to be the predominant pathogen followed by Klebsiella (19.63%), Staphylococcus aureus (18.10%), E. coli (15.95%), Acinetobacter (12.27%) and Enterococcus spp. (1.84%). EONS was seen in 195(59.82%) cases and LONS was seen in 131(40.18%) cases. Gram-negative bacteria are predominant in EONS (76.28%) and gram-positive bacteria is predominant in LONS (64.12%). Gram negative isolates are mostly susceptible to Meropenem, Piperacillin-tazobactam, Cefepime, Ceftazidime. Gram positive isolates mostly showed sensitivity to Vancomycin, Linezolid.Multi-drug resistant organism are emerging in neonatal septicemia. Strict antibiotic stewardship should be practiced to avoid the upcoming treatment difficulties.

scholarly journals TSPphg Lysin from the Extremophilic Thermus Bacteriophage TSP4 as a Potential Antimicrobial Agent against Both Gram-Negative and Gram-Positive Pathogenic Bacteria

Viruses ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 192 ◽  
Author(s):  
Feng Wang ◽  
Xinyu Ji ◽  
Qiupeng Li ◽  
Guanling Zhang ◽  
Jiani Peng ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Infection Model ◽  
Bacterial Cells ◽  
Skin Damage ◽  
Gram Positive ◽  
Antibiotic Resistant ◽  
Gram Negative

New strategies against antibiotic-resistant bacterial pathogens are urgently needed but are not within reach. Here, we present in vitro and in vivo antimicrobial activity of TSPphg, a novel phage lysin identified from extremophilic Thermus phage TSP4 by sequencing its whole genome. By breaking down the bacterial cells, TSPphg is able to cause bacteria destruction and has shown bactericidal activity against both Gram-negative and Gram-positive pathogenic bacteria, especially antibiotic-resistant strains of Klebsiella pneumoniae, in which the complete elimination and highest reduction in bacterial counts by greater than 6 logs were observed upon 50 μg/mL TSPphg treatment at 37 °C for 1 h. A murine skin infection model further confirmed the in vivo efficacy of TSPphg in removing a highly dangerous and multidrug-resistant Staphylococcus aureus from skin damage and in accelerating wound closure. Together, our findings may offer a therapeutic alternative to help fight bacterial infections in the current age of mounting antibiotic resistance, and to shed light on bacteriophage-based strategies to develop novel anti-infectives.

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