Identification of Virulence Factors , Accessory Gene Regulator ( AGR ) Locus and Antibiotic Resistance Pattern of Staphylococcus Aureus Isolated from Diabetic Foot Ulcers

2015 ◽  
Vol 24 (4) ◽  
pp. 41-47
Author(s):  
Rania Talaat Abdel Haleem ◽  
Magda Mohammad El Nagdy ◽  
Nesreen Salah Omar
2021 ◽  
Vol 11 (05) ◽  
pp. 283-295
Author(s):  
Jean-Marie Liesse Iyamba ◽  
Victoire Marie Hermine Ngo Bassom ◽  
Cyprien Mbundu Lukukula ◽  
Joseph Welo Unya ◽  
Benjamin Kodondi Ngbandani ◽  
...  

2013 ◽  
Vol 20 (4) ◽  
pp. 389-393 ◽  
Author(s):  
Teodora Chiţă ◽  
Delia Muntean ◽  
Luminiţa Badiţoiu ◽  
Bogdan Timar ◽  
Roxana Moldovan ◽  
...  

Abstract Background and aims: Infected foot ulcer is one of the most feared complications of diabetes mellitus. Staphylococcus aureus is the most frequently isolated pathogen in diabetic foot infections. The aim of this study was to evaluate the prevalence of S. aureus strains involved in producing foot infections in diabetic patients and the antibiotic resistance pattern of these strains. Material and methods: The study included 33 S. aureus strains isolated from 55 diabetic foot ulcers. The subjects were selected from the 2465 patients with diabetes mellitus hospitalized in the Timişoara Diabetes Clinic, between 2011 and 2013. Germs’ identification relied on cultural and biochemical characteristics. Final identification and antimicrobial testing were performed using the Vitek 2 (Bio Merieux France) automatic analyzer. Results: All the 55 samples collected from diabetic foot ulcers were positive. We isolated 64 bacterial strains (some samples were positive for 2 microorganisms). The most frequently isolated germ was S. aureus, in 33 samples (51.56%). All these S. aureus strains showed resistance to benzylpenicillin, while only 33.33% were methicillin-resistant (MRSA). Conclusions: The most frequently isolated germ in the wound secretions from diabetic foot ulcers was S. aureus. The highest percentage of antimicrobial resistance was recorded to benzylpenicillin and erythromycin.


Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 937
Author(s):  
Ramzy B. Anafo ◽  
Yacoba Atiase ◽  
Nicholas T. K. D. Dayie ◽  
Fleischer C. N. Kotey ◽  
Patience B. Tetteh-Quarcoo ◽  
...  

Aim: This study investigated the spectrum of bacteria infecting the ulcers of individuals with diabetes at the Korle Bu Teaching Hospital in Accra, Ghana, focusing on Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), with respect to their prevalence, factors predisposing to their infection of the ulcers, and antimicrobial resistance patterns. Methodology: This cross-sectional study was conducted at The Ulcer Clinic, Department of Surgery, Korle Bu Teaching Hospital, involving 100 diabetic foot ulcer patients. The ulcer of each study participant was swabbed and cultured bacteriologically, following standard procedures. Antimicrobial susceptibility testing was done for all S. aureus isolated, using the Kirby-Bauer method. Results: In total, 96% of the participants had their ulcers infected—32.3% (n = 31) of these had their ulcers infected with one bacterium, 47.9% (n = 46) with two bacteria, 18.8% (n = 18) with three bacteria, and 1.0% (n = 1) with four bacteria. The prevalence of S. aureus and MRSA were 19% and 6%, respectively. The distribution of the other bacteria was as follows: coagulase-negative Staphylococci (CoNS) (54%), Escherichia coli (24%), Pseudomonas spp. (19%), Citrobacter koseri and Morganella morgana (12% each), Klebsiella oxytoca (11%), Proteus vulgaris (8%), Enterococcus spp. (6%), Klebsiella pneumoniae (5%), Proteus mirabilis and Enterobacter spp. (4%), Klebsiella spp. (2%), and Streptococcus spp. (1%). The resistance rates of S. aureus decreased across penicillin (100%, n = 19), tetracycline (47.4%, n = 9), cotrimoxazole (42.1%, n = 8), cefoxitin (31.6%, n = 6), erythromycin and clindamycin (26.3% each, n = 5), norfloxacin and gentamicin (15.8% each, n = 3), rifampicin (10.5%, n = 2), linezolid (5.3%, n = 1), and fusidic acid (0.0%, n = 0). The proportion of multidrug resistance was 47.4% (n = 9). Except for foot ulcer infection with coagulase-negative Staphylococci, which was protective of S. aureus infection of the ulcers (OR = 0.029, p = 0.001, 95% CI = 0.004–0.231), no predictor of S. aureus, MRSA, or polymicrobial ulcer infection was identified. Conclusions: The prevalence of S. aureus and MRSA infection of the diabetic foot ulcers were high, but lower than those of the predominant infector, coagulase-negative Staphylococci and the next highest infecting agent, E. coli. Diabetic foot ulcers’ infection with coagulase-negative Staphylococci protected against their infection with S. aureus. The prevalence of multidrug resistance was high, highlighting the need to further intensify antimicrobial stewardship programmes.


2015 ◽  
Vol 14 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Estrella Cervantes-García ◽  
Rafael García-González ◽  
Aldo Reséndiz-Albor ◽  
Paz Maria Salazar-Schettino

mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Vishal Gor ◽  
Aya J. Takemura ◽  
Masami Nishitani ◽  
Masato Higashide ◽  
Veronica Medrano Romero ◽  
...  

ABSTRACT Staphylococcus aureus is an important human pathogen whose success is largely attributed to its vast arsenal of virulence factors that facilitate its invasion into, and survival within, the human host. The expression of these virulence factors is controlled by the quorum sensing accessory gene regulator (Agr) system. However, a large proportion of clinical S. aureus isolates are consistently found to have a mutationally inactivated Agr system. These mutants have a survival advantage in the host but are considered irreversible mutants. Here we show, for the first time, that a fraction of Agr-negative mutants can revert their Agr activity. By serially passaging Agr-negative strains and screening for phenotypic reversion of hemolysis and subsequent sequencing, we identified two mutational events responsible for reversion: a genetic duplication plus inversion event and a poly(A) tract alteration. Additionally, we demonstrate that one clinical Agr-negative methicillin-resistant S. aureus (MRSA) isolate could reproducibly generate Agr-revertant colonies with a poly(A) tract genetic mechanism. We also show that these revertants activate their Agr system upon phagocytosis. We propose a model in which a minor fraction of Agr-negative S. aureus strains are phase variants that can revert their Agr activity and may act as a cryptic insurance strategy against host-mediated stress. IMPORTANCE Staphylococcus aureus is responsible for a broad range of infections. This pathogen has a vast arsenal of virulence factors at its disposal, but avirulent strains are frequently isolated as the cause of clinical infections. These isolates have a mutated agr locus and have been believed to have no evolutionary future. Here we show that a fraction of Agr-negative strains can repair their mutated agr locus with mechanisms resembling phase variation. The agr revertants sustain an Agr OFF state as long as they exist as a minority but can activate their Agr system upon phagocytosis. These revertant cells might function as a cryptic insurance strategy to survive immune-mediated host stress that arises during infection.


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