Sensitivity pattern of methicillin resistant and methicillin sensitive Staphylococcus aureus isolates, against several antibiotics including tigecycline in Iran: a hospital based study

Methicillin resistant Staphylococcus aureus [MRSA] is a major nosocomial pathogen causing significant morbidity and mortality. The aim of this study was to evaluate in vitro activity of tigecycline and other new agents against MRSA, isolated from surgical wound and soft tissue infections in an Iranian 1000-bed tertiary hospital. In vitro activity of tigecycline and other antibiotics were tested against 102 strains of Staphylococcus aureus isolated from different patients hospitalized at Milad hospital from May 2008 to June 2008. All strains were identified according to routine bacteriological methods. Susceptibility testing was performed by disk diffusion methods as recommended by Clinical Laboratory Standards Institute [CLSI]. Cefoxitin [30 micri g] disk used for detection of methicillin resistant strains of S.aureus. One hundred two strains of S.aureus were isolated from patients admitted to our hospital. The majority of patients was from surgical wards including open heart, orthopedic ward and had post operation wound infections. Of 102 strains 36[35.3%] isolates were MRSA. All isolates including MRSA strains were susceptible to tigecyline, linozolide and vancmycin. Of 102 isolated strains 96 [94.1%] were susceptible to teicoplanine and six stains [5.9%] were intermediate. Resistant rate to other antibiotics including clindamycinm erythromycin pencillin, co-trimoxazole, rifampicin and ciprofloxacin were 35.3%, 27.7%, 97.7%, 26.5%, 16.7%and 33.7% respectively. All strains of S.aureus, isolated from wound and soft tissue in our hospital were susceptible to tigecyline, linozolide and vancomycin

Carbapenem resistance in gram-negative bacilli isolates in an Iranian 1000-bed tertiary hospital

Carbapenems are beta-lactamase antibiotics, presently considered as most potent agents for treatment of infections caused by Gram-negative bacilli. The aim of this study was to determine resistance of Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumonniae as prevalent nosocomial agents to commonly used antibiotics including carbapenems such as imipenem and meropenem. A total of 202 gram-negative bacilli including K. pneumoniae, P aeruginosa and A. baumannii isolated from hospitalized patients in Milad hospital of Tehran were subject for susceptibility testing. Susceptibility testing was performed by disk diffusion and MIC methods as recommended by Clinical Laboratory Standards Institute [CLSI]. All isolates of K. pneumonia were susceptible to imipenem and meropenem. Resistance in non-fermenting gram-negative bacilli [NFGB] was prevalent. P. aeruginosa isolates exhibited 7.5% and 40.2% resistance to imipenem and meropenem respectively. The majority isolates of Acinetobacter baumannii were multi-drug resistant and resistance of this organism to imipenem and meropenem was 27.7% and 38.5% respectively. Our study revealed that in spite of resistance of K. pneumoniae to commonly used antibiotics, all isolates were susceptible to imipenem and meropeem. More than 80% isolates of A. bammanni were resistant to commonly used antibiotics. About 40.2% isolates of P. aeruginosa and [38.5%] isolates of A. baumannii were resistant to meropenem respectively