Emergence of Multidrug Resistance and Metallo‑beta‑lactamase Producing Acinetobacter baumannii Isolated from Patients in Shiraz, Iran

Background: Metallo‑beta‑lactamase (MβL) enzymes production is one of the most important resistance mechanisms against carbapenems in some bacteria including Acinetobacter baumannii. Aims: This study was aimed to determine the antimicrobial susceptibility and the prevalence of MβL among carbapenem‑resistant isolates of A. baumannii. Materials and Methods: In this cross‑sectional study from October 2012 to April 2013, 98 isolates were identified as A. baumannii using Microgen™ kits and confirmed by molecular method. These isolates were tested for antimicrobial susceptibilities by disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. Carbapenem‑resistant isolates were further detected phenotypically by MβL minimal inhibitory concentration (MIC)‑test strips, and subsequently positive MβL isolates were confirmed by polymerase chain reaction (PCR). Results: Overall, 98% (96/98) of A. baumannii isolates were detected as carbapenem‑resistant by MIC test. Highest sensitivity to the tested antibiotic with 42.9% (42/98) was observed to colistin. Of 96 carbapenem‑resistant isolates, 43 were phenotypically positive for MβL; out of 43 isolates, 37 were confirmed for the presence of MβL genes by PCR. Conclusion: The frequency of drug resistance among the clinical samples of A. baumannii isolated in our study against most of the antibiotics was very high. Moreover, all MβL producing isolates were multidrug resistance. Therefore, systematic surveillance to detect MβL producing bacteria and rational prescription and use of carbapenems could be helpful to prevent the spread of carbapenem resistance.Keywords: Acinetobacter baumannii, Antibiotic resistance, Carbapenem, Iran, Metallo‑beta‑lactamas

Epidemiology of toxic shock syndrome toxin-1 harboring Staphylococcus aureus obtained from clinical samples in Iran: A Systematic Review and Meta-analysis

BACKGROUND: S. aureus strains, with the capability of producing toxic shock syndrome toxin-1 (TSST-1), are more likely to cause complicated infections. However, due to lack of comprehensive local data on the prevalence of TSST-1, we aimed to determine the prevalence of TSST-1 harboring S. aureus isolates in Iran. METHODS: A systematic search was performed by using PubMed and Scopus databases from papers published by Iranian authors from January 2000 to the end of March 2017. Then, 10 publications which were matched with inclusion criteria were selected for data extraction and analysis by Comprehensive Meta-Analysis Software. RESULTS: The overall prevalence of TSST-1 carrying S. aureus in Iran was 21.3% (95% CI: 7.9%-46.1%), ranging from 0% to 68%. Moreover, from the included studies, the pooled prevalence of TSST-1 producing MRSA isolates was estimated to be 25.2% (95% CI: 13.3%-42.5%), ranging from 0% to 69.8%. From those studies which showed the distribution of toxin-harboring S. aureus it was found that the skin and soft tissue, respiratory and bloodstream infections were the common sites of TSST-1 harboring S. aureus. CONCLUSIONS: In summary, it seems that emergence of MRSA strains leads to higher prevalence of TSST-1 carrying strains in the north of Iran. However, further research is required to elucidate the interplay between the outcome of diseases and TSST-1 producing strains, especially in our country