scholarly journals Variation in Biofilm-Forming Potential of Staphylococcus aureus from Clinical and Non-Clinical Sources

Author(s):  
K. Otokunefor ◽  
J. J. Jesutobi ◽  
O. E. Agbagwa

Introduction: Biofilm forming ability has been described as a potential marker of pathogenicity, particularly in Staphylococcus aureus. These biofilms are notable as an important contributor to virulence abilities, further aiding the producing strain in long term survival and resistance to antimicrobial agents. Regional data exploring biofilm forming ability of S. aureus from various sources is limited. This study therefore set out to explore variations in biofilm-forming potential of S. aureus from clinical and non-clinical sources. Place and Duration of Study: Medical Microbiology Laboratory, Department of Microbiology, University of Port Harcourt, Nigeria from August to October 2019. Methodology: Eighty five S. aureus clinical and non-clinical isolates were studied. Biofilm-forming potential was assessed using the Congo Red agar (CRA) method which describes both the presence and degree biofilm-forming potential. Results: Majority of isolates (65.9%) did not exhibit any biofilm-forming potential using the CRA method. Biofilm-forming potential however appeared source based with 100% of non-clinical S. aureus isolates lacking biofilm-forming potential, while 58% of clinical isolates showed biofilm-forming potential. A higher proportion (65.5%) of the clinical isolates exhibiting biofilm-forming potential where associated with strong biofilm-forming potential. Conclusion: This study reports a high association of biofilm-forming potential with S. aureus isolated from clinical rather than non-clinical settings. If this characteristic can indeed be used as a general marker of pathogenicity would however require more extensive studies.

2020 ◽  
Vol 21 (12) ◽  
pp. 4529
Author(s):  
Simon Eppich ◽  
Christina Kuhn ◽  
Elisa Schmoeckel ◽  
Doris Mayr ◽  
Sven Mahner ◽  
...  

Prognostic factors are of great interest in patients with endometrial cancer. One potential factor could be the protein MSX1, a transcription repressor, that has an inhibitory effect on the cell cycle. For this study, endometrioid endometrial carcinomas (n = 53), clear cell endometrial carcinomas (n = 6), endometrioid ovarian carcinomas (n = 19), and clear cell ovarian carcinomas (n = 11) were immunochemically stained for the protein MSX1 and evaluated using the immunoreactive score (IRS). A significant stronger expression of MSX1 was found in endometrioid endometrial carcinomas (p < 0.001), in grading 2 (moderate differentiation) (p = 0.001), and in tumor material of patients with no involvement of lymph nodes (p = 0.031). Correlations were found between MSX1 expression and the expression of β-Catenin, p21, p53, and the steroid receptors ERα, ERβ, PRα, and PRβ. A significant (p = 0.023) better survival for patients with an MSX1 expression in more than 10% of the tumor cells was observed for endometrioid endometrial carcinomas (21.3 years median survival (MSX1-positive) versus 17.3 years (MSX1-negative)). Although there is evidence that MSX1 expression correlates with improved long-term survival, further studies are necessary to evaluate if MSX1 can be used as a prognostic marker.


2013 ◽  
Vol 18 (3) ◽  
pp. 102-109 ◽  
Author(s):  
Chong W. Ong ◽  
Jan L. Roberts ◽  
Peter J. Collignon

2003 ◽  
Vol 185 (10) ◽  
pp. 3214-3217 ◽  
Author(s):  
Nicky C. Caiazza ◽  
G. A. O'Toole

ABSTRACT Staphylococcus aureus is a common pathogen associated with nosocomial infections. It can persist in clinical settings and gain increased resistance to antimicrobial agents through biofilm formation. We have found that alpha-toxin, a secreted, multimeric, hemolytic toxin encoded by the hla gene, plays an integral role in biofilm formation. The hla mutant was unable to fully colonize plastic surfaces under both static and flow conditions. Based on microscopy studies, we propose that alpha-hemolysin is required for cell-to-cell interactions during biofilm formation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yaqian Liu ◽  
Pengfei She ◽  
Lanlan Xu ◽  
Lihua Chen ◽  
Yimin Li ◽  
...  

Staphylococcus aureus has increasingly attracted global attention as a major opportunistic human pathogen owing to the emergence of biofilms (BFs) and persisters that are known to increase its antibiotic resistance. However, there are still no effective antimicrobial agents in clinical settings. This study investigated the antimicrobial activity of penfluridol (PF), a long-acting antipsychotic drug, against S. aureus and its clinical isolates via drug repurposing. PF exhibited strong bactericidal activity against S. aureus, with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 4–8 and 16–32 μg/ml, respectively. PF could significantly inhibit biofilm formation and eradicate 24 h preformed biofilms of S. aureus in a dose-dependent manner. Furthermore, PF could effectively kill methicillin-resistant S. aureus (MRSA) persister cells and demonstrated considerable efficacy in a mouse model of subcutaneous abscess, skin wound infection, and acute peritonitis caused by MRSA. Notably, PF exerted almost no hemolysis activity on human erythrocytes, with limited cytotoxicity and low tendency to cause resistance. Additionally, PF induced bacterial membrane permeability and ATP release and further caused membrane disruption, which may be the underlying antibacterial mechanism of PF. In summary, our findings suggest that PF has the potential to serve as a novel antimicrobial agent against S. aureus biofilm- or persister-related infections.


2005 ◽  
Vol 187 (13) ◽  
pp. 4488-4496 ◽  
Author(s):  
Indranil Chatterjee ◽  
Petra Becker ◽  
Matthias Grundmeier ◽  
Markus Bischoff ◽  
Greg A. Somerville ◽  
...  

ABSTRACT The ability of Staphylococcus aureus to adapt to various conditions of stress is the result of a complex regulatory response. Previously, it has been demonstrated that Clp homologues are important for a variety of stress conditions, and our laboratory has shown that a clpC homologue was highly expressed in the S. aureus strain DSM20231 during biofilm formation relative to expression in planktonic cells. Persistence and long-term survival are a hallmark of biofilm-associated staphylococcal infections, as cure frequently fails even in the presence of bactericidal antimicrobials. To determine the role of clpC in this context, we performed metabolic, gene expression, and long-term growth and survival analyses of DSM20231 as well as an isogenic clpC allelic-replacement mutant, a sigB mutant, and a clpC sigB double mutant. As expected, the clpC mutant showed increased sensitivity to oxidative and heat stresses. Unanticipated, however, was the reduced expression of the tricarboxylic acid (TCA) cycle gene citB (encoding aconitase), resulting in the loss of aconitase activity and preventing the catabolization of acetate during the stationary phase. clpC inactivation abolished post-stationary-phase recovery but also resulted in significantly enhanced stationary-phase survival compared to that of the wild-type strain. These data demonstrate the critical role of the ClpC ATPase in regulating the TCA cycle and implicate ClpC as being important for recovery from the stationary phase and also for entering the death phase. Understanding the stationary- and post-stationary-phase recovery in S. aureus may have important clinical implications, as little is known about the mechanisms of long-term persistence of chronic S. aureus infections associated with formation of biofilms.


2020 ◽  
pp. 1-2
Author(s):  
Asmita Singh ◽  
Anita Pandey ◽  
Amit Singh ◽  
Priyanka Chaturvedi

BACKGROUND: Staphylococcus aureus is a major human pathogen that causes wide range of clinical infections. Methicillin-resistant Staphylococcus aureus(MRSA) is endemic in India and is a dangerous pathogen causing hospital acquired infection leadings to signicant morbidity and mortality. OBJECTIVE:To study the prole of Staphylococcus aureusisolated from patients admitted in a tertiary care hospital. RESULT: Majority of clinical isolates of S.aurueswas obtained from patients of skin and soft tissue infection(54.66%) followed by those suffering from respiratory infection (13.33%), blood stream infection (13.33%) and UTI(8%). S.aureus was predominantly isolated from IPD samples, maximum cases were in the age group of 31-40 years and males outnumbered females. There was predominance of MRSA 112 (74.66%)which showed high level of resistance to penicillin (100%), ciprooxacin (82.14 %), co-trimoxazole (79.46%) and moxioxacin(85.71%). All the clinical isolates of S.aureuswere sensitive to linezolid andvancomycin (MIC <1ugm/ml). CONCLUSIONS: The clinical isolates of S.aureusshowed high level of resistance to various antimicrobial agents which is a signicant nosocomial threat. Surveillance and infection control practices should be carried out to prevent cross transmission of such resistant pathogen within the hospital setting


2021 ◽  
Vol 14 (3) ◽  
pp. 1449-1457
Author(s):  
Salma Osman Noorelhuda Mohammed ◽  
Nadir Musa Khalil Abuzeid ◽  
Sara Abdelghani ◽  
Lienda Bashier Eltayeb

Background:Methicillin-resistant Staphylococcus aureus (MRSA) has gained significant health solicitude globallydue to its resistance to nearly almost antimicrobial agents, and garlic is one of nature's most powerful antibiotics that must be used as a pharmaceutical regimen. The current study aimed to determine the In-Vitro antibacterial efficacy of crude garlic extract against MRSA. Methods: The aqueous and 70% ethanol crude garlic (Alllium sativum)extract was prepared. Disc diffusion method was performed to assess the antimicrobial activity for100 clinical isolates of MRSA collected,The reference standard strain was Staphylococcus aureus (ATCC 25923). Results: All MRSA strains assessed were significantly sensitive to 70% ethanolic extract at various concentrations range from 200 to 25%, exhibited inhibitory effects against clinical isolates and Staphylococcus aureus (ATCC 25923) with the means of inhibition zones ranging from 17.76- 14.35 mm and 15-13 mm in length, while the aqueous extracts were less in both clinical isolates and Staphylococcus aureus (ATCC 25923) ranging from 11.93-8.62 mm and 11-8 mm respectively, methanol and distilled water were not effected on growth. Conclusion: The findings demonstrate that 70%ethanol extract of crude Allium sativum has significantly inhibitory effect on methicillin-resistant Staphylococcus aureus is better than aqueous extract. This study does not undermine the value of antibiotic use, but instead the probability of using them in low dosage to minimize their negative consequences.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4741-4741
Author(s):  
Fang Fang ◽  
Guoxiang Wang ◽  
Ronghua Hu ◽  
Wuhan Hui ◽  
Hong Zhao ◽  
...  

Abstract Background:There is no standard treatment recommendation for POMES syndrome, a rare clonal plasm cell disease. Although autologous hematopoietic stem cell transplantation (ASCT) has been considered to have advantage in remission rate and long-term survival, but in most newly diagnosed cases, it is not applicable to conduct ASCT directly because of the severity of patients' conditions. Combined chemotherapy, applied in other plasm cell disorder, is a choice for POEMS syndrome. Both melphalan and lenalidomide have been proved to be effective in POEMS syndrome, but the long-term administration of these agents might damage hematopoietic stem cells and result in failure of stem cell mobilization. Proteasome inhibitor, bortezomib based regimen is also the first-line treatment in other plasm cell dyscrasia. In this study, we investigated and evaluated the effect and safety of the bortezomib-based combined chemotherapy in newly diagnosed POEMS syndrome patients. Method: POEMS syndrome patients newly diagnosed from July 2013 to August 2020 in Xuanwu hospital, Capital Medical University, were enrolled. Informed consent was obtained. Four cycles of Bortezomib-based 28-day BCD regimen (bortezomib 1.3mg/m 2 sc d1,8,15,22, cyclophosphamide iv 0.4g/m 2 d1,15, dexamethasone 40mg iv d1,8,15,22) were used as induction therapy. After the induction, ASCT or another two cycles of BCD therapy were conducted as consolidation therapy. Patients diagnosed in the same period but refusing bortezomib were treated with CD/CTD regimen (the same as BCD without bortezomib), and thalidomide 50-100mg once daily was suggested if it was well-tolerated. (Figure A) Results: There were totally 22 newly diagnosed POEMS syndrome patients accepted BCD regimen, and 16 patients CD/CTD regimen. First of all, the response rate in BCD group was superior to CD/CTD group, no matter the VEGF remission rate or hematologic complete remission rate (Figure B1-B4). The median time to achieve VEGF CR was 133 days in BCD group and 214 days in CD/CTD group. The median time to achieve hematologic remission was 218 days in BCD group and 415 days in CD/CTD group. Secondly, the improvement of neurologic symptoms in BCD group was not inferior to CD/CTD group. Bortezomib was well tolerated and didn't deteriorate the polyneuropathy (Figure C1-C3). Thirdly, during the median 35 months follow-up, the overall 5-year OS of 31 patients was 93.55%, 3-year and 5-year PFS were 83.47% and 76.51% respectively (Figure D1-D2). The 5-year-OS and 3-year and 5-year PFS of BCD group were superior to CD/CTD group (Figure D3-D4). In the consideration of ASCT significantly improve OS and PFS in POEMS syndrome patients, the long-term survival results were analyzed among ASCT group and cheotherapy only groups. The BCD+ASCT group achieved a best 5-year OS and 3-year and 5-year PFS (Figure D5-D6). Fourthly, about 54% of male patients had a subnormal testosterone at diagnosis, with normal or slightly elevated LH. After treatment, testosterone returned to normal level in male patients with the VEGF CR and VEGF PR (Figure E1). And the median remission time of testosterone was 76 days, which was earlier than that of VEGF remission was 143 days. The testosterone returned to normal after two cycle treatment predicted a better PFS. (Figure E2). About 86% of men at diagnosis had elevated estradiol which is the most common gonadal hormone abnormalities. After treatment, patients with better treatment response would have lower estradiol level (Figure E3-E4). Estradiol less than 58pg/ml after two cycle treatment and estradiol less than 48pg/ml after four cycle treatment predicted a better 5-year PFS (FigureE5-E6). After four cycle treatment, slightly elevated estradiol (48-79pg/ml) may be at risk for later recurrence and significant elevated estradiol tended to progress early (Figure E5). In women, low LH was frequently observed. Two patients with persistent low LH died within 1 year of diagnosis. Persistent low LH level in female patients may be an important predictor for poor prognosis. Conclusion: Bortezomib-based BCD regimen in newly diagnosed POEMS syndrome patients seems improve the response rate and survival, especially in patients with sequential ASCT. Recovery of gonadal hormone level might be a potential marker for response and prognosis. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.


Sign in / Sign up

Export Citation Format

Share Document