scholarly journals Resistance of nosocomial strains to antibacterial drugs and its link to biofilm formation

2017 ◽  
Vol 8 (4) ◽  
pp. 540-546
Author(s):  
T. V. Sklyar ◽  
K. V. Lavrentievа ◽  
Y. A. Alyonkina ◽  
A. M. Kolomoets ◽  
А. І. Vinnikov

The problem of nosocomial infections is considered in connection with more frequent formation and wide distribution in clinical practice of new strains of hospital bacteria that have a cross-resistence to antibacterial drugs. The nosocomial agents were isolated from wounds and identified as Staphylococcus aureus and Pseudomonas aeruginosa. 72.0% of S. aureus strains and 61.5% of P. aeruginosa clinical isolates had the capability of forming biofilms. The sensitivity to antibiotics of all isolated strains was investigated with tne agar diffusion test. This method showed that all strains of S. aureus with the capability to form biofilms had resistence to erythromycin, gentamycin, ciprofloxacin and levofloxacin. The had the greatest sensitivity to klindamycin (90.3%), vancomycin (80.6%) and gatifloxacin (80.6% cultures). The strains of S. aureus with the capability to form biofilms were more resistent to antibiotics than strains of S. aureus without such properties. Only cefotaxim suppressed the growth of 75.0% of strains of staphylococci. All isolated strains of S. aureus without the capability to form biofilms were sensitive to doxycyclin, gentamycin, ciprofloxacin, levofloxacin and klindamycin. All clinical isolates of P. aeruginosa with capability to form biofilms had resistence to ampicillin, gentamycin, imipenem, cefotaxime and ceftriaxone. They were most sensitive (75.0%) to piperacillin and cefoperazone/sulbactam. The strains of P. aeruginosa without the capability to form biofilms kept the resistence to gentamycin, imipenem and ceftriaxone. They showed the greatest sensitivity (75.0%) to ciprofloxacin (80.0% isolates) and also to amikacin, ampicillin, meropenem, norfloxacin and cefotaxime (60.0% cultures). We investigated the minimum inhibitory concentrations of gentamycin and ciprofloxacin, which appeared higher for P. aeruginosa than for S. aureus. The most effective disinfectant against all isolated nosocomial agents without the capacity for biofilm formation was “Desactin” in a concentration 0.1% or 0.2%. For strains of staphylococci with this capability, the efficiency of “Desactin” went down by 9.7%. The best biocide effect against the strains of P. aeruginosa with the capability of forming biofilms was shown by 0.1% solution of “Neochlorine tabs”, which suppressed the growth of 75.0% of tested cultures. As a result, we detected a direct relationship between resistance to antibiotics and disinfectants and the capacities for biofilm formation among the nosocomial agents S. aureus and P. aeruginosa. 

2021 ◽  
pp. 1-8
Author(s):  
Soheir A.A. Hagras ◽  
Alaa El-Dien M.S. Hosny ◽  
Omneya M. Helmy ◽  
Mounir M. Salem-Bekhit ◽  
Faiyaz Shakeel ◽  
...  

This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½–1/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymeric chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.


F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 14
Author(s):  
Dina Auliya Amly ◽  
Puspita Hajardhini ◽  
Alma Linggar Jonarta ◽  
Heribertus Dedy Kusuma Yulianto ◽  
Heni Susilowati

Background: Pseudomonas aeruginosa, a multidrug-resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may potentially overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth, pyocyanin production, and biofilm formation of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC 10145 and clinical isolates were cultured in a royal jelly-containing medium to test the antibacterial activity. Pyocyanin production was observed by measuring the absorbance at 690 nm after 36 h culture and determined using extinction coefficient 4310 M-1 cm-1. Static microtiter plate biofilm assay performed to detect the biofilm formation, followed by scanning electron microscopy. Results: Royal jelly effectively inhibited the viability of both strains from a concentration of 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC 10145, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Concentrations of 12.5% and 6.125% significantly induced biofilm formation of P. aeruginosa ATCC 10145, in line with the results of the SEM analysis. Conclusions: The royal jelly concentration of 25% or higher inhibits bacterial growth; however, the subinhibitory concentration increases pyocyanin production and biofilm formation in P. aeruginosa. It is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.


2021 ◽  
Author(s):  
Hossein Jafari Soghondicolaei ◽  
Mohammad Ahanjan ◽  
Mehrdad Gholami ◽  
Bahman Mirzaei ◽  
Hamid Reza Goli

Abstract Biofilm production increases Staphylococcus aureus resistance to antibiotics and also host defense mechanisms. The current study aims to evaluate the biofilm formation by S. aureus and to determine the prevalence of fibronectin-binding protein genes, also its correlation with drug resistance. In this study, 100 clinical isolates of S. aureus were collected. The antibiotic susceptibility pattern of the isolates was evaluated by the disk agar diffusion method. The ability of biofilm formation in the studied isolates was also determined by microplate colorimetric assay. Then, all isolates were screened by polymerase chain reaction for the fnbA and fnbB genes. Out of 100 clinical isolates of S. aureus, the highest and lowest antibiotic resistance rates were against penicillin (94%) and vancomycin (6%). Thirty-two cases were found to be multi-drug resistant (MDR) among the all strains. The ability of biofilm production was observed in 89% of the isolates. The PCR results showed that the prevalence of fnbA and fnbB genes were 91% and 17%, respectively. Moreover, 100% and 21.8% of the MDR strains harbored the fnbA and fnbB genes respectively. The ability to form biofilm in MDR isolates of S. aureus is more than non-MDR isolates, especially fnbA positive ones. As the bacteria in the biofilm are difficult to kill by antibiotics, attention to the removal or control of the biofilm production seems to be necessary.


Author(s):  
Fateme DAVARZANI ◽  
Navid SAIDI ◽  
Saeed BESHARATI ◽  
Horieh SADERI ◽  
Iraj RASOOLI ◽  
...  

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.


2010 ◽  
Vol 0 (3(11)) ◽  
pp. 32-40
Author(s):  
I. О. Малярчик ◽  
Т. О. Філіпова ◽  
Т. О. Філіпова ◽  
Б. М. Галкін ◽  
Б. М. Галкін

Sign in / Sign up

Export Citation Format

Share Document