Quaid-i-Azam University

Staphylococcus aureusis a critical global health threat due to its multidrug resistance (MDR) and virulence. We examined the relationship between MDR and virulence in 250 clinical S. aureus isolates using the Galleria mellonella infection model. Alpha-hemolysin was the most prevalent toxin, with its gene, hla, present in the majority of hemolytic strains. Other virulence genes, including sigB, codY, fnbA, fnbB, clfA, saeS, sarA, arlS, yycG, spoVG, rot, and PVL, were widely distributed across methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates. The ica gene showed a notable increase in expression in hospital-acquired (HA-MRSA) and community-acquired (CA-MRSA) strains. In vivo infections revealed that HA-MRSA strains were more virulent than vancomycin intermediate S. aureus VISA, CA-MRSA, MSSA, and an agr mutant strain, while locally sourced CA-MRSA exhibited the highest virulence among tested strains. Despite differences in antibiotic resistance, MRSA and MSSA shared largely similar virulence gene profiles. These findings highlight the complex interplay between MDR and virulence in S. aureus and emphasize the need for further mechanistic studies.Importance: S. aureus remains a major clinical concern due to its increasing multidrug resistance (MDR) and virulence. Understanding the relationship between resistance mechanisms and virulence is essential for guiding effective treatment and infection control. This study assessed the virulence potential of 250 MDR S. aureus isolates using a clinically relevant invertebrate model (G. mellonella), revealing key virulence gene profiles. Notably, CA-MRSA strains exhibited hypervirulence, with alpha-hemolysin as the most prevalent toxin and significant upregulation of the ica gene in both CA- and HA-MRSA isolates. These findings emphasize the growing threat of CA-MRSA and the importance of integrated surveillance of both resistance and virulence in S. aureus populations.

The paper examined how the flipped teaching method can be used to develop the conceptual knowledge among secondary school students studying the chemical industry. The objective of the research was to understand whether a flipped classroom method could be an effective way of enhancing the conceptual learning of students as opposed to conventional lecture-based teaching. Quasi-experimental research design was adopted in which a pre-test-post-test control group design was used. The research was carried out among high school learners taking chemistry. Two intact groups were then taken with one being the experimental group taught by use of flipped instruction and the other group being treated as the control group taught in a traditional way. Experimental group students watched instructional videos before class; in-class time focused on collaboration, problem-solving, and concept clarification. A tested conceptual understanding test was applied in the form of pre-test and post-test in order to gather the data. A statistical test was made on the differences between the groups in terms of appropriate inferential statistics. The findings indicated a statistically significant difference in the conceptual knowing of students exposed to flipped teaching and those taught using the traditional way of teaching. Flipped classroom increased student engagement, promoted active learning, and enhanced understanding of complex chemical industry concepts effectively. The results indicate that the technique of flipped instruction could be also effective as a pedagogical method to teach the complicated topics in chemistry. Digital tools and interactive lessons boost students' conceptual understanding and make science learning more meaningful.