Staphylococcus aureus is a nosocomial bacterium causing different infectious diseases, ranging from skin and soft tissue infections to more serious and life-threatening infections such as septicaemia. S. aureus forms a complex structure of extracellular polymeric biofilm that provides a fully secured and functional environment for the formation of microcolonies, their sustenance and recolonization of sessile cells after its dispersal. Staphylococcus aureus biofilm protects the cells against hostile conditions, i.e., changes in temperature, limitations or deprivation of nutrients and dehydration, and, more importantly, protects the cells against antibacterial drugs. Drugs are increasingly becoming partially or fully inactive against S. aureus as they are either less penetrable or totally impenetrable due to the presence of biofilms surrounding the bacterial cells. Other factors, such as evasion of innate host immune system, genome plasticity and adaptability through gene evolution and exchange of genetic material, also contribute to the ineffectiveness of antibacterial drugs. This increasing tolerance to antibiotics has contributed to the emergence and rise of antimicrobial resistance (AMR), a serious problem that has resulted in increased morbidity and mortality of human and animal populations globally, in addition to causing huge financial losses to the global economy. The purpose of this review is to highlight different aspects of S. aureus biofilm formation and its overall architecture, individual biofilm constituents, clinical implications and role in pathogenesis and drug resistance. The review also discusses different techniques used in the qualitative and quantitative investigation of S. aureus biofilm and various strategies that can be employed to inhibit and eradicate S. aureus biofilm.

Amino acids are ubiquitous vital biomolecules found in all kinds of living organisms including those in the microbial world. They are utilised as nutrients and control many biological functions in microorganisms such as cell division, cell wall formation, cell growth and metabolism, intermicrobial communication (quorum sensing), and microbial-host interactions. Amino acids in the form of enzymes also play a key role in enabling microbes to resist antimicrobial drugs. Antimicrobial resistance (AMR) and microbial biofilms are posing a great threat to the world’s human and animal population and are of prime concern to scientists and medical professionals. Although amino acids play an important role in the development of microbial resistance, they also offer a solution to the very same problem i.e., amino acids have been used to develop antimicrobial peptides as they are highly effective and less prone to microbial resistance. Other important applications of amino acids include their role as anti-biofilm agents, drug excipients, drug solubility enhancers, and drug adjuvants. This review aims to explore the emerging paradigm of amino acids as potential therapeutic moieties.

Methicillin-resistant Staphylococcus aureus (MRSA) is a clinically prevalent bacterium and is resistant to many drugs. Genetic factors such as mec genes are considered to be responsible for this resistance. Recently, Staphylococcal Cassette Chromosome mec (SCCmec) element mutations produced mecC, a new genetic variant that encodes a transpeptidase enzyme (63% similarity with mecA-encoded PBP2a). This cross-sectional study was conducted to establish the prevalence of the mecA and mecC genes among phenotypically identified MRSA and their effectiveness against different antibiotics in clinical specimens. The prevalence of Staphylococcus aureus was 10.2% (n = 102) in the total number of clinical specimens collected (n = 1000). However, the prevalence of MRSA was 6.3% (n = 63) of the total samples collected, while it was 61.8% among total Staphylococcus aureus isolates. mec genes were confirmed in 96.8% (n = 61) isolates of MRSA, while 3.2% (n = 2) were found to be negative for mec genes. The combination of mecA and mecC was detected in 57.1% (n = 36) of the MRSA isolates. The prevalence of lone mecA was 31.8% (n = 20) and that of lone mecC was 7.9% (n = 5) among all the MRSA samples. Penicillin and amoxicillin/clavulanic acid were the most resistant antibiotics followed by norfloxacin (91.2%), levofloxacin (87.1%), ciprofloxacin (83.9%), azithromycin (78.6%), erythromycin (77.4%), moxifloxacin (69.8%), and sulfamethoxazole/trimethoprim (54.9%). On the other hand, vancomycin and teicoplanin (98.4%) were more effective drugs against MRSA followed by linezolid (96.7%), clindamycin (84.6%), chloramphenicol (83.7%), fusidic acid (70.6%), gentamicin (67.7%), and tetracycline (56.8%). In conclusion, a significant prevalence of mecA and mecC has been found among MRSA isolated from clinical specimens, which is likely responsible for antibiotic resistance in MRSA in our clinical settings. However, vancomycin, teicoplanin, and linezolid were found the top three most effective drugs against MRSA in our clinical settings. Thus, MRSA endemics in local areas require routine molecular and epidemiological investigation.

Background Urinary tract infections (UTIs) are a common infection caused by uropathogenic bacteria. Drug resistance against common antibiotics is a leading cause of treatment failure in UTIs. Objective This study was conducted to check the prevalence of antimicrobial susceptibility against uropathogens and identify the best treatment option against UTIs. Methods In this cross-sectional study, urine samples (n = 1000) were collected and cultured for pure bacterial growth by using cysteine–lactose–electrolyte-deficient (CLED) media. After physical and biochemical characterization, antibacterial susceptibility was performed by the Kirby–Bauer disk diffusion method. Results Uropathogenic bacteria were successfully isolated in 57% (n = 572) of total tested samples (n = 1000). Escherichia coli 51.2% (n = 293/572), Klebsiella species 15.4% (n = 88/572), Enterococcus species 15.4% (n = 88/572), Pseudomonas species 9.4% (n = 54/572), Staphylococcus aureus 3.2% (n = 18/572), coagulase-negative Staphylococci (CoNS) 3.0% (n = 17/572) and Proteus species 2.4% (n = 14/572) were the most prevalent organism in UTIs. Prevalence of Gram-negative rods (GNRs) was 78.5% (n = 449/572) among UTI patients as compared to Gram-positive cocci (GPCs) 21.5% (n = 123/572). Escherichia coli 65.3% (n = 293/449), Klebsiella species 19.6% (n = 88/449), Pseudomonas species 12.0% (54/449) and Proteus species 3.1% (n = 14/449) were the most prevalent GNRs in UTIs, while Enterococcus species 71.5% (n = 88/123), Staphylococcus aureus 14.6% (n = 18/123) and coagulase-negative Staphylococci (CoNS) 13.8% (17/123) were the most prevalent GPCs in UTIs. The majority of isolated uropathogens showed resistance against routinely used antibiotics. However, teicoplanin and linezolid were the most effective drugs against GPCs and piperacillin/tazobactam, meropenem and imipenem were the most effective drugs against GNRs. Nitrofurantoin and fosfomycin were shown to be most effective against both GNRs and GPCs. Conclusion In conclusion, Escherichia coli (GNRs) and Enterococcus species (GPCs) are the most prevalent organisms among UTIs patients, which are shown to be antibiotic-resistant to the most commonly used antibiotics. However, nitrofurantoin and fosfomycin are the most effective drugs against uropathogens in UTIs.