ABSTRACT
OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major health hazards and became of greater public health concern since the emergence of community-acquired MRSA. This work aimed to study the prevalence of mecA, femA, femB, lukS-PV, lukF-PV (PVL), intI, and intII genes among community-acquired (CA) hospital-acquired (HA) MRSA to increase vigilance in the diagnosis and management of suspected infections. MATERIALS AND METHODS: S. aureus isolates recovered from clinical samples were classified into community or hospital-acquired and tested for their antibiotic susceptibility against 19 antibiotics. All isolates were screened for mecA, femA, femB, lukS-PV, lukF-PV, intI, and intII genes. Statistical correlations were carried out. RESULTS: Out of 338 S. aureus isolates, only 105 were MRSA and classified as 77 CA-MRSA and 28 HA-MRSA. mecA and femA genes were present in all HA-MRSA and CA-MRSA isolates. femB was found in all HA-MRSA and 93.5% of CA-MRSA isolates. PVL genes were detected in 28.6% HA-MRSA isolates and 92.2% CA-MRSA. intI gene was recovered from 60.7% HA-MRSA isolates and 37.7% CA-MRSA isolates while the intII gene recovered from only 10.7% HA-MRSA isolates and 6.5% CA-MRSA. CONCLUSION: The high prevalence of MRSA colonizing the groin, axilla, and nose may play a significant role in endogenous infection, re-infection, and also acts as a route for MRSA transmission. mecA and femA genes could be used as a sole and fast step for identification of MRSA, while PVL genes cannot be used as a sole stable marker for CA-MRSA identification.
ABSTRACT
A bacterial isolate capable of tolerating 30 mM silver nitrate (AgNO3) was recovered from soil contaminated with industrial waste. The isolate was identified by 16S rRNA as Enterobacter cloacae Ism26 (KP988024) and its capability to synthesize silver nanoparticles (AgNPs) was investigated. AgNPs were produced by mixing 1 mM AgNO3 solution with bacterial cell lysate under light conditions. The UV-Vis spectrum of the aqueous medium containing AgNPs exhibited a peak at 440 nm corresponding to the surface plasmon resonance of the AgNPs. The crystalline nature of the particles was confirmed by X-ray difractometer. High-resolution transmission electron microscopy revealed that the AgNPs were spherical and well dispersed and ranged in size from 7 to 25 nm. The average size range of the produced AgNPs was confirmed by dynamic light scattering. Fourier transform infrared spectroscopy revealed possible involvement of reductive groups on the surface of the nanoparticles. The biosynthesized AgNPs were stable for 6 months and inhibited both gram-positive and gram-negative bacteria. This work describes the exploitation of a low-cost biomaterial and an easy method for the synthesis of AgNPs with desirable and advantageous characteristics.
