No abstract

Linezolid, an oxazolidinone antimicrobial agent that acts by inhibiting protein synthesis in a unique fashion, is used in the treatment of community-acquired pneumonia, skin and soft-tissue infections and other infections caused by Gram-positive bacteria including VRE and methicillin-resistant staphylococci. Currently, linezolid resistance among these pathogens remains low, commonly <1.0%, although the prevalence of antibiotic resistance is increasing in many countries. Therefore, the development of resistance by clinical isolates should prompt increased attention of clinical laboratories to routinely perform linezolid susceptibility testing for this important agent and should be taken into account when considering its therapeutic use. Considering the importance of linezolid in the treatment of infections caused by Gram-positive bacteria, this review was undertaken to optimize the clinical use of this antibiotic.

This is the first known description of ESBL-producing and AmpC β-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-β-lactamase-producing Shigella should be implemented.

Background: Extended-spectrum beta (β)-lactamase (ESBL)-producing enterobacteria are major emerging pathogens in nosocomial infections. Methodology: The combination disk synergy test was used to evaluate 202 consecutive non-repeated Klebsiella pneumoniae (K. pneumonia) strains for ESBL production. The strains were isolated from various clinical specimens of hospitalized patients over the period from July 2005 to March 2007. Their antibiotic susceptibility pattern was also determined by the disk diffusion method. Demographic and medical data of the patients were recorded using a questionnaire. Results: One hundred and fifty-seven (77.7%) of the isolates were confirmed as ESBL-producers. By univariate analysis, young age, stay in intensive care unit (ICU)/medical wards, recent stay in ICU, and number of days of ICU stay were found to be risk factors for acquisition of resistant bacteria (χ2 and Mann-Whitney U tests, P < 0.05). However, binary logistic multivariate regression analysis confirmed that stay in ICU [Odds ratio (OR) 6.09, 95% confidence interval (CI) 2.36-15.72; P < 0.001] or medical wards [OR 3.72, 95% CI 1.42-9.75; P = 0.007] were significantly associated with ESBL production. Imipenem, ofloxacin, cefoxitin and norfloxacin (against urinary isolates) were found to be highly active against ESBL-producing isolates in vitro (100%, 75.2%, 69.4% and 66.7% susceptibility, respectively). In addition to most β-lactams, they showed co-resistance with other antibiotics such as ciprofloxacin, aminoglycosides, trimethoprim/sulfamethoxazole and tetracycline. Conclusion: Our results showed a high prevalence of ESBL-producing K. pneumoniae in our hospital setting. As the available treatment options are limited, antibiotic control policies together with the implementation of infection control measures remain of high importance.

This study indicated that the 13-valent pneumococcal conjugate vaccine (PCV13) could cover the majority of the invasive pneumococcal isolates. Drug-resistant and multidrug-resistant Streptococcus pneumoniae strains are circulating in Iran. Therefore, public immunization of infants using PCV13 is recommended to reduce the incidence of pneumococcal disease and pneumococcal-resistant strains in Teheran.