In vitro susceptibility to methicillin, vancomycin and linezolid of staphylococci isolated from bloodstream infections in eastern Turkey

Assessing the effectiveness of green synthesized zinc oxide nanoparticles in controlling multidrug-resistant clinical bacteria

Multi-drug resistant pathogenic bacteria are life threaten agent associated with the misuse and overuse of antibiotics. The biological synthesis of metal oxide nanoparticles is a promising alternative treatment. The current study reported the synthesis of zinc oxide nanoparticles (ZnONPs) using different plants extracts of garlic (Allium sativum), ginger (Zingiber officinale), and lemon (Citrus lemon). The plant extracts not only acts as reducing agents but as stabilizing agents for the produced nanoparticles. Biosynthesized zinc oxide nanoparticles (ZnONPs) were confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy-dispersive X-ray studies (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and ultraviolet-visible (UV-vis) spectroscopy. XRD analysis confirmed the production of pure ZnONPs. UV-vis spectroscopy revealed the presence of ZnONPs and reported the characteristic absorption peak of ZnONPs at 370 nm. SEM and TEM confirmed the shape and size of nanoparticles, with an average mean size of 0.3-11.40 nm. This study reported the antibacterial activity and minimum inhibitory concentration of biosynthesized ZnONPs using the broth microdilution method against some clinical pathogenic bacteria. This study also reported the antimicrobial activity of ZnONPs prepared with garlic extract against Enterococcus sp. and Pseudomonas sp. While, those prepared with ginger extract were effective against Enterococcussp. and methicillin-resistant Staphylococcus aureus. ZnONPs synthesized by garlic extract were more powerful and effective than ZnONPs synthesized by ginger and lemon extracts.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-022-01048-3.

Study of biofilm formation, structure and antibiotic resistance in Staphylococcus saprophyticus strains causing urinary tract infection in women in Ahvaz, Iran

Staphylococcus saprophyticus is the second most frequent community-acquired causative agent of acute urinary tract infection (UTI). Some strains of S. saprophyticus can create biofilms, increasing their virulence. Once biofilms have been produced, antibiotic resistance is exacerbated. Hence, the aims of the present study were the study of biofilm formation, structure and antibiotic resistance in S. saprophyticus strains causing UTIs in women in Ahvaz, Iran. Overall, 43 S. saprophyticus isolates were recovered from UTIs. Antibiotic resistance pattern and the biofilm production and structure were determined using phenotypic methods. Most S. saprophyticus isolates were resistant to erythromycin, but all isolates were sensitive to linezolid and vancomycin. Fifty-eight per cent of S. saprophyticus were multidrug resistant. Twenty-one per cent of S. saprophyticus isolates harbored the mecA gene. Biofilm formation was observed in 65% of S. saprophyticus isolates and most had polysaccharide matrix. Our data indicate high rates of antibiotic resistance and the capability of biofilm formation among S. saprophyticus isolates. The emergence of antibiotic resistance in the management of UTIs is a serious public health issue. The findings of this study could be used to improve treatment plans to control UTIs. Consequently, increased awareness of the mechanisms underlying biofilm formation and the development of drug resistance will allow UTIs to be more efficiently controlled and treated.

The global prevalence of Daptomycin, Tigecycline, Quinupristin/Dalfopristin, and Linezolid-resistant Staphylococcus aureus and coagulase-negative staphylococci strains: a systematic review and meta-analysis

Objective

Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MRCoNS) are among the main causes of nosocomial infections, which have caused major problems in recent years due to continuously increasing spread of various antibiotic resistance features. Apparently, vancomycin is still an effective antibiotic for treatment of infections caused by these bacteria but in recent years, additional resistance phenotypes have led to the accelerated introduction of newer agents such as linezolid, tigecycline, daptomycin, and quinupristin/dalfopristin (Q/D). Due to limited data availability on the global rate of resistance to these antibiotics, in the present study, the resistance rates of S. aureus, Methicillin-resistant S. aureus (MRSA), and CoNS to these antibiotics were collected.

Method

Several databases including web of science, EMBASE, and Medline (via PubMed), were searched (September 2018) to identify those studies that address MRSA, and CONS resistance to linezolid, tigecycline, daptomycin, and Q/D around the world.

Result

Most studies that reported resistant staphylococci were from the United States, Canada, and the European continent, while African and Asian countries reported the least resistance to these antibiotics. Our results showed that linezolid had the best inhibitory effect on S. aureus. Although resistances to this antibiotic have been reported from different countries, however, due to the high volume of the samples and the low number of resistance, in terms of statistical analyzes, the resistance to this antibiotic is zero. Moreover, linezolid, daptomycin and tigecycline effectively (99.9%) inhibit MRSA. Studies have shown that CoNS with 0.3% show the lowest resistance to linezolid and daptomycin, while analyzes introduced tigecycline with 1.6% resistance as the least effective antibiotic for these bacteria. Finally, MRSA and CoNS had a greater resistance to Q/D with 0.7 and 0.6%, respectively and due to its significant side effects and drug-drug interactions; it appears that its use is subject to limitations.

Conclusion

The present study shows that resistance to new agents is low in staphylococci and these antibiotics can still be used for treatment of staphylococcal infections in the world.