Phenotypic and Genotypic Determination of Resistance to Common Disinfectants Among Strains of Pseudomonas Aeruginosa Producing and Non-Producing Biofilm Isolated From Iran

Mehdi Bakht ◽  
Safar Ali Alizadeh ◽  
Sara Rahimi ◽  
Raana Kazemzade anari ◽  
Mohammad Rostamani ◽  

Abstract Background: One of the most important reasons for human mortality worldwide is Hospital-acquired infections, which can be controlled by efficient use of proper disinfectants for the Hospital settings. The main aim of the present survey was to assess the susceptibility of Pseudomonas aeruginosa producing and non-producing biofilm isolated to the five commonly used Hospital disinfectants, and evaluation of the synergistic effect of selective disinfectants and Ethylene-diamine-tetra acetic acid (EDTA), and the effect of exposure to sub-inhibitory concentrations of Sodium hypochlorite on antimicrobial susceptibility test.Results: The results showed that Sodium hypochlorite 5%, and Ethanol 70% is the most and less potent disinfectants against Pseudomonas aeruginosa, respectively. Clearly, the addition of EDTA increased the efficacy of selected disinfectants significantly. The changes in the antibiotic-resistance profiles after exposure to sub-inhibitory concentrations of disinfectants were observed for different classes of antibiotics. As well as near the all isolates harbored efflux pump genes and produced biofilm. Conclusion: For disinfection of Hospital surfaces and instruments, the mixture of disinfectant and EDTA were the most suitable selection in this study. In our study, it was clear that exposure to sub-inhibitory concentrations of disinfectants results in resistance to antibiotics. Also, strong and intermediate biofilm formers belonged to MDR/XDR strains.

2014 ◽  
Vol 63 (4) ◽  
pp. 544-555 ◽  
Hansi Kumari ◽  
Deepak Balasubramanian ◽  
Diansy Zincke ◽  
Kalai Mathee

Pseudomonas aeruginosa is one of the most dreaded opportunistic pathogens accounting for 10 % of hospital-acquired infections, with a 50 % mortality rate in chronically ill patients. The increased prevalence of drug-resistant isolates is a major cause of concern. Resistance in P. aeruginosa is mediated by various mechanisms, some of which are shared among different classes of antibiotics and which raise the possibility of cross-resistance. The goal of this study was to explore the effect of subinhibitory concentrations (SICs) of clinically relevant antibiotics and the role of a global antibiotic resistance and virulence regulator, AmpR, in developing cross-resistance. We investigated the induction of transient cross-resistance in P. aeruginosa PAO1 upon exposure to SICs of antibiotics. Pre-exposure to carbapenems, specifically imipenem, even at 3 ng ml−1, adversely affected the efficacy of clinically used penicillins and cephalosporins. The high β-lactam resistance was due to elevated expression of both ampC and ampR, encoding a chromosomal β-lactamase and its regulator, respectively. Differences in the susceptibility of ampR and ampC mutants suggested non-AmpC-mediated regulation of β-lactam resistance by AmpR. The increased susceptibility of P. aeruginosa in the absence of ampR to various antibiotics upon SIC exposure suggests that AmpR plays a major role in the cross-resistance. AmpR was shown previously to be involved in resistance to quinolones by regulating MexEF–OprN efflux pump. The data here further indicate the role of AmpR in cross-resistance between quinolones and aminoglycosides. This was confirmed using quantitative PCR, where expression of the mexEF efflux pump was further induced by ciprofloxacin and tobramycin, its substrate and a non-substrate, respectively, in the absence of ampR. The data presented here highlight the intricate cross-regulation of antibiotic resistance pathways at SICs of antibiotics and the need for careful assessment of the order of antibiotic regimens as this may have dire consequences. Targeting a global regulator such as AmpR that connects diverse pathways is a feasible therapeutic approach to combat P. aeruginosa pathogenesis.

mSystems ◽  
2021 ◽  
Su-fang Kuang ◽  
Ding-yun Feng ◽  
Zhuang-gui Chen ◽  
Zhuo-zheng Liang ◽  
Juan-juan Xiang ◽  

Infections with Pseudomonas aeruginosa have become a real concern among hospital-acquired infections, especially in cystic fibrosis patients and immunocompromised individuals. Control of the pathogen is challenging due to antibiotic resistance.

1979 ◽  
Vol 82 (1) ◽  
pp. 31-40 ◽  
Heather J. L. Brooks ◽  
T. J. Chambers ◽  
Soad Tabaqchali

SUMMARYA 14-month survey was undertaken in a diagnostic bacteriology laboratory to determine the incidence ofSerratiaspp. in routine clinical specimens. Gram-negative organisms with enterobacteria-like colonies were tested by a simple screening procedure. Fifty-eight strains ofS. marcescensand two strains ofS. liquefacienswere isolated from 59 patients. The strains were usually nonpigmented and exhibited multiple antibiotic resistance. Serotyping and determination of bacteriocine sensitivity patterns revealed that the majority of infections were sporadic, although episodes of cross-infection did occur.S. marcescenswas considered to contribute significantly to morbidity and mortality in 53% of patients and appears to be of increasing importance in hospital-acquired infections.

2017 ◽  
Leon Zhen Wei Tan ◽  
Joey Kuok Hoong Yam ◽  
Ziyan Hong ◽  
May Margarette Santillan Salido ◽  
Bau Yi Woo ◽  

AbstractPseudomonas aeruginosa is widely attributed as the leading cause of hospital-acquired infections. Due to intrinsic antibiotic resistance mechanisms and the ability to form biofilms, P. aeruginosa infections are challenging to treat. P. aeruginosa employs multiple virulence mechanisms to establish infections, many of which are controlled by the global virulence regulator Vfr. An attractive strategy to combat P. aeruginosa infections is thus the use of anti-virulence compounds. Here, we report the discovery that FDA-approved drug auranofin attenuates virulence in P. aeruginosa. We demonstrate that auranofin acts by targeting Vfr, which in turn leads to inhibition of quorum sensing (QS) and Type IV pili (TFP). Consistent with inhibition of QS and TFP expression, we show that auranofin attenuates biofilm maturation, and when used in combination with colistin, displays strong synergy in eradicating P. aeruginosa biofilms. Auranofin may have immediate applications as an anti-virulence drug against P. aeruginosa infections.

2015 ◽  
Vol 72 (11) ◽  
pp. 996-1003 ◽  
Natasa Stankovic-Nedeljkovic ◽  
Branislav Tiodorovic ◽  
Branislava Kocic ◽  
Vojislav Ciric ◽  
Marko Milojkovic ◽  

Introduction/Aim. Pseudomonas aeruginosa (P. aeruginosa) is the most common cause of wound infections, following the disruption of the skin or mucous membranes integrity. The aim of this study was to analyze of the presence P. aeruginosa in wound swabs, antibiotics susceptibility testing, determination of the minimum inhibitory concentrations (MICs) of antibiotics, testing of the metallo-?-lactamases (MBLs) production, isolates serotyping and analysis of the most common serotypes resistance. Methods. A total of 90 outpatients and 55 intpatients wound swabs were cultivated. Wound swabs were taken from the patients with wound infections symptoms. Antibiotics susceptibility testing was performed to: meropenem, imipenem, piperacillin-tazobactam, ceftazidime, cefepime, amikacin, gentamicin, netilmicin, ofloxacin, ciprofloxacin and colistin (HiMedia). Polyvalent and monovalent antisera for agglutination (Biorad) were used in P. aeruginosa agglutination. Results. P. aeruginosa was isolated from 36.55% wound swabs (36.66% of the inpatients wounds and 36.36% of the outpatients). The analyzed isolates showed the highest degree of sensitivity to colistin (100%) and meropenem (93.44%) and the lowest to cefepime (19.54%). The majority of the inpatients isolates had 12 ?g/mL (28.57%) MIC for piperacillin-tazobactam and 16 ?g/mL (28.57%) for the outpatients. The most common MICs for ciprofloxacin were 0.19 ?g/mL (31.81%) for the nosocomial isolates, and 0.25 ?g/mL (28.57%) for the outpatients? ones. The most common MICs for amikacin of the nosocomial isolates were 6 ?g/ml (40.9%), and for the outpatients ones 4 ?g/mL (33.33%). Five (9.43%) isolates produced MBLs. The most common serotypes were P11 (22.64%), P6 (15.09%) and P1 (11.32%). Conclusion. Neither the increased presence of P. aeruginosa was noticed in wounds swabs, nor the antibiotic resistance in the nosocomial isolates compared to those from outpatients. The analyzed isolates had the higest sensitivity to colistin and meropenem, and the lowest to cefepime.

L. Yu. Kulagina ◽  
I. R. Valiullina ◽  
E. R. Kadyseva ◽  
M. L. Maksimov

Relevance. Conducting microbiological monitoring allows controlling hospital-acquired infections and making timely strategic decisions for epidemiologists and clinical pharmacologists. Objective of the work is to determine the tendency of prevailing problem microflora and to develop a strategy of empirical antibacterial therapy for severe nosocomial infections and inflammatory processes. Materials and methods. The article analyzes the main groups of pathogens of hospital infections in dynamics for the first quarter of 2018, 2019 and 2020. The relation of positive cultures to the total number of investigated samples was taken for the analysis. Antibiotic sensitivity was isolated, identified and determined using conventional mass spectrometry methods. The results. The stable sowing rate of Acinetobacter baumannii and Klebsiella pneumoniae in the intensive care and surgical departments was noted for the analyzed periods. To solve the issue of antibiotic resistance in the inpatient department, a strategy to contain it has been developed.

2018 ◽  
Vol 4 (12) ◽  
pp. 2051-2057 ◽  
Fuzheng Zhao ◽  
Qing Hu ◽  
Hongqiang Ren ◽  
Xu-Xiang Zhang

UV irradiation disturbs the regulatory system of efflux pump proteins to sensitize P. aeruginosa to multiple antibiotics. The increasing susceptibility to rifampicin and vancomycin might be caused by UV-mediated mutations in antibiotic resistance genes.

2019 ◽  
Vol 8 (9) ◽  
Bárbara Magalhães ◽  
Laurence Senn ◽  
Dominique S. Blanc

Pseudomonas aeruginosa is one of the major Gram-negative pathogens responsible for hospital-acquired infections. Here, we present high-quality genome sequences of isolates from three P. aeruginosa genotypes retrieved from patients hospitalized in intensive care units.

2020 ◽  
Vol 8 (11) ◽  
pp. 1652
Olga Pappa ◽  
Anastasia Maria Kefala ◽  
Kyriaki Tryfinopoulou ◽  
Marios Dimitriou ◽  
Kostas Kostoulas ◽  

Resistant Pseudomonas aeruginosa isolates are one of the major causes of both hospital-acquired infections (HAIs) and community-acquired infections (CAIs). However, management of P. aeruginosa infections is difficult as the bacterium is inherently resistant to many antibiotics. In this study, a collection of 75 P. aeruginosa clinical isolates from two tertiary hospitals from Athens and Alexnadroupolis in Greece was studied to assess antimicrobial sensitivity and molecular epidemiology. All P. aeruginosa isolates were tested for susceptibility to 11 commonly used antibiotics, and the newly introduced Double Locus Sequence Typing (DLST) scheme was implemented to elucidate the predominant clones. The tested P. aeruginosa isolates presented various resistant phenotypes, with Verona Integron-Mediated Metallo-β-lactamase (VIM-2) mechanisms being the majority, and a new phenotype, FEPR-CAZS, being reported for the first time in Greek isolates. DLST revealed two predominant types, 32-39 and 8-37, and provided evidence for intra-hospital transmission of the 32-39 clone in one of the hospitals. The results indicate that DLST can be a valuable tool when local outbreaks demand immediate tracking investigation with limited time and financial resources.

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