Search

Background: Healthcare-associated infections (HAIs) caused by multidrug-resistant bacteria (MDRB) are of global concern and hospital textiles can contribute to their transmission. MDRB are able to survive on textiles for more than enough time to spread in the environment. Some studies summarized the effect of environmental factors on the duration of bacterial survival, but it remained an open question how these factors influence the quantity of surviving bacteria in a period of a few days, which is relevant from the perspective of HAIs. Investigating this effect can contribute to better understand the spread of MDRB and the emergence of hospital outbreaks., Methods: We investigated quantitatively the survival capability of 15 vancomycin-resistant Enterococcus faecium (VRE), 15 methicillin-resistant Staphylococcus aureus (MRSA), 15 multidrug-resistant Acinetobacter baumannii (MACI) and 15 multidrug-resistant Klebsiella pneumoniae (MRKP) in five environmental conditions using the plate count method. We examined the role of nutrients, textile types, temperature and level of relative humidity on bacterial survival after 1-7days of incubation., Results: Each bacterial group showed higher survival capability on 100% cotton towel than on 100% cotton sheet (P<0.01). MRSAs and VREs showed higher (P<0.01), MACIs showed lower (P=0.02) CFU/swatch values on 100% polyester sheet than on cotton sheet. The survival capability of MRKPs and MRSAs was higher inoculated in nutrient broth than in saline solution (P<0.01). Each bacterial group showed lower survival capability (P<0.01) at body condition (T=35°C, Rh=83%) than at control (T=25°C, Rh=52%)., Conclusions: Towels proved to be excellent conditions for each bacteria to survive, however chemical composition of the textiles affected differently the survival of Gram-positive and Gram-negative bacteria. These findings could be useful in searching for the source of outbreaks. Organic contamination of the textiles can increase the survival of desiccation-sensitive bacteria, therefore nutrient-rich inoculating medium is recommended in survival studies., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Nosocomially-acquired multi-, extensively-, and pandrug resistant (MDR, XDR, and PDR) strains of microorganisms such as Acinetobacter baumannii remain a serious cause of infection and septic mortality in burn patients. Treatment of patients with nosocomial burn wound infections is often complicated by drug-resistant strains of A. baumannii. Today, many researchers are focusing on the investigation of novel non-antibiotic strategies such as photodynamic therapy (PDT). We report a new PDT strategy that suppresses colistin resistance in PDR A. baumannii by interfering with the expression of a pmrA/pmrB two-component system. In the current study, A. baumannii with a PDR feature isolated from a burn patient was used as a test strain. PDT was carried out using toluidine blue O (TBO) and light-emitting diode (LED) as a photosensitizer and radiation source, respectively. The antimicrobial susceptibility profiles were assessed for cells surviving PDT. The effects of sub-lethal PDT (sPDT) on the expression of the pmrA/pmrB two-component signal transduction system were evaluated by real-time quantitative reverse transcription PCR. Results of drug susceptibly testing (DST) in LED and TBO groups separately showed that the bacteria were resistant to all tested antibiotics, while the DST result of the LED+TBO group showed highly declining bacterial growth when compared with the control group. Reduction in the expression of pmrA and pmrB was observed in the treated strains after sPDT. This represents the first conclusive example of a direct role for the PDT in breaking antibiotic resistance by directly modulating two-component system activity., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Introduction: Widespread resistance to antimicrobial agents has led to a dearth of therapeutic choices in treating Acinetobacter baumannii infections, leading to new strategies for treatment being needed. We evaluated the effects of photodynamic therapy (PDT) as an alternative antimicrobial modality on the virulence features of cell-surviving PDT., Materials and Methods: To determine the sublethal PDT (sPDT), a colistin-resistant, extensively drug-resistant A. baumannii (CR-XDR-AB) clinical isolate and A. baumannii and ATCC 19606 strains, photosensitized with toluidine blue O (TBO), were irradiated with light emitting diodes, following bacterial viability measurements. The biofilm formation ability, outer membrane (OM) integrity, and antimicrobial susceptibility profiles were assessed for cell-surviving PDT. The effects of sPDT on the expression of virulent genes were evaluated by real-time quantitative reverse transcription PCR (qRT-PCR)., Results: sPDT resulted in the reduction of the biofilm formation capacity, and its metabolic activity in strains. The OM permeability and efflux pump inhibition of the sPDT-treated CR-XDR-AB cells were increased; however, there was no significant change in OM integrity in ATCC 19606 strain after sPDT. sPDT reduced the minimum inhibitory concentrations of the most tested antimicrobials by ≥2-fold in CR-XDR-AB. lpsB, blsA, and dnaK were upregulated after the strains were treated with sPDT; however, a reduction in the expression of csuE, epsA, and abaI was observed in the treated strains after sPDT., Conclusion: The susceptibility of CR-XDR-AB to a range of antibiotics was enhanced following sPDT. The virulence of strains is reduced in cells surviving PDT with TBO, and this may have potential implications of PDT for the treatment of A. baumannii infections., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Epidemics spread many types of pathogenic bacterial strains, especially strains of MRSA (Methicillin-resistant Staphylococcus aureus), which are being increasingly reported in many geographical areas [1]. This is becoming to be a serious global problem, particularly in hospitals. Not only are antibiotics proving to be increasingly ineffective but also the bacteria responsible for more than 70% of hospital-acquired bacterial infections are resistant to at least one of the drugs commonly used to treat them. In this study, hybrid coating A1 and nanocomposite hybrid coating A2 based on TMSPM (3-(trimethoxysilyl)propyl methacrylate, MMA (methyl methacrylate), TEOS (tetraethyl orthosilicate) and IPTI (titanium isopropoxide) containing silver and copper ions with or without nanoparticles of titanium dioxide were prepared by the sol-gel method. They were deposited on glass, poly(methyl methacrylate) and cotton using dip-coating or spin-coating, and then cured at 150 °C for 3 h or, in the case of poly(methyl methacrylate), at 100 °C for 4.5 h. The morphology and microstructure of these hybrid coatings were examined by SEM. The abrasion resistance was tested using a washability tester and found to depend heavily on the curing temperature. Seven types of bacterial strains were used to determine the profile of antibacterial activity, namely Escherichia coli, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus - MRSA (CCM 4223), MRSA-2 (CCM 7112), Acinetobacter baumanii, Pseudomonas aeruginosa, and Proteus vulgaris (according to ALE-G18, CSNI). All the samples were tested by irradiating with either a UV-A or a daylight fluorescent lamp. All types of hybrid coating A1 and nanocomposite hybrid coating A2 were found to possess an excellent antibacterial effect, including against the pathogenic bacterial strains of MRSA, which present a dangerous threat on a global scale., (Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.)