Infectious diseases caused by bacterial pathogens represent a serious public health concern. Antimicrobial agents such as anti-bacterial drugs are often indicated for chemotherapy of bacterial infections in clinical medicine. Thus, it is important to study the biological mechanisms that confer bacterial pathogenesis and virulence. Under selective evolutionary pressure when in the presence of an...

Recent evidence has shown that antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are ubiquitous in natural environments, including sites considered pristine. To understand the origin of ARGs and their dynamics, we must first define their actual presence in the natural bacterial assemblage. Here we found varying distribution profiles of sul genes in "colony forming bacte...

Fitness landscapes are central in analyzing evolution, in particular for drug resistance mutations for bacteria and virus. We show that the fitness landscapes associated with antibiotic resistance are not compatible with any of the classical models; additive, uncorrelated and block fitness landscapes. The NK model is also discussed. It is frequently stated that virtually nothing is known about ...

Antibiotic resistance is a major public health concern. This study was conducted to evaluate the knowledge, attitudes of community pharmacists regarding antibiotic use and potential drug resistance besides assessing their behaviors about dispensing antibiotic without prescription and correlation of the outcomes with demographic variables. A cross-sectional survey was conducted on a random sampl...

Antibiotic resistance is ancient and widespread in environmental bacteria. These are therefore reservoirs of resistance elements and reflective of the natural history of antibiotics and resistance. In a previous study, we discovered that multi-drug resistance is common in bacteria isolated from Lechuguilla Cave, an underground ecosystem that has been isolated from the surface for over 4 Myr. He...

A new national antimicrobial resistance surveillance program in Singapore public hospitals that uses WHONET detected high levels of methicillin resistance among Staphylococcus aureus (35.3%), carbapenem resistance among Acinetobacter spp. (49.6%), and third-generation cephalosporin resistance among Klebsiella pneumoniae (35.9%) hospital isolates in 2006. Antimicrobial drug resistance is a major...

The fitness effects of a mutation can depend, sometimes dramatically, on genetic background; this phenomenon is often referred to as "epistasis." Epistasis can have important practical consequences in the context of antimicrobial resistance (AMR). For example, genetic background plays an important role in determining the costs of resistance, and hence in whether resistance will persist in the a...