Evaluation of venom diversity and antivenom quality from the venom of long-term captive vs recently wild captured Pseudocerastes persicus snake: An In vitro and In vivo study.

Snakebite envenomation is a life-threatening condition and antivenoms are used as the most effective treatment. Venom obtained from snakes in long-term captivity showed some variations in comparison to the venom of the wild snakes. The objective of this study is to compare the venom of the Pseudocerastes persicus under long-term captivity and wild conditions as well as the antivenom obtained from these venoms. We have analyzed venom samples and produced trivalent antivenoms using the venom of long-term captive (LTC) or recently wild-captured (RWC) Pseudocerastes persicus, and RWC Macrovipera lebetina, and Echis carinatus. The HPLC analysis revealed that the RWC snakes' venom had three peaks that were not present in the LTC snake's venom. Further analysis using MALDI-TOF and MS/MS showed that the fraction with a retention time (RT) of 14 min contained a toxin from the Kunitz-type serine protease inhibitor (KUT) class, while the fraction with RT 21 a peptide identified within the snake venom metalloproteinase (SVMP) class. The third peak was identified as a sphingolipid. Interestingly, the in vivo preclinical tests showed no significant differences in the effectiveness of the antivenoms. which could be due to the cross-immunogenicity or cross-reactivity between different toxins in the venom. According to our results, small variations in the venom composition of a species do not lead to a decrease in the efficacy of the polyvalent antivenom.

Changes in 4-year antimicrobial resistance pattern of gram-positive bacteria at the main referral teaching hospital, Tehran, Iran.

Infectious diseases are one of the most common causes of morbidity and mortality and the spread of resistant microorganisms is playing a significant role in this regard. The purpose of this study was to assess the trend in antimicrobial resistance of gram-positive bacteria at the main referral teaching hospital in Tehran during a 4-year period. All patients' biological isolates such as blood, urine, wound drainage, synovial fluid, sputum, and cerebrospinal fluid sent to the central laboratory of the hospital from 2007 to 2010 for identification and subsequently, antimicrobial susceptibility testing by Kirby-Bauer disc diffusion method were considered. All isolates (100%) of S. aureus were sensitive to vancomycin and linezolid and resistant to amoxicillin. The rate of S. aureus resistance to oxacillin increased from 60.78% in 2007 to 72% in 2010. All isolates of Streptococci in 2007 and 2008 were sensitive to vancomycin; while, 3.33% and 4.76% of Streptococci isolates were reported to be vancomycin-resistant in 2009 and 2010, respectively. Enterococci isolated from the entire specimens were identified to be sensitive to teicoplanin and linezolid and resistant to cloxacillin and oxacillin. The rates of Enterococci sensitivity to vancomycin were 90.91%, 81.25%, 86.67%, and 93.3% in 2007, 2008, 2009, and 2010, respectively. Changes of antibiotics sensitivity against g positive pathogens were significant during four years in this study. To minimize the spread of resistant gram positive pathogens, periodic and regular surveillance of antimicrobial resistance pattern is highly recommended.

Changes in gram negative microorganisms' resistance pattern during 4 years period in a referral teaching hospital; a surveillance study.

BACKGROUND AND PURPOSE: Surveillance studies evaluating antimicrobial susceptibilities are of great value in preventing the spread of resistant pathogens by elucidating the trend of resistance in commonly used antibiotics and as a consequence providing information for prescribing the most appropriate agent. This study is a longitudinal antimicrobial resistance surveillance study designed to evaluate the trend in antimicrobial resistance to gram negative microorganisms from 2007 to 2010. METHOD: During a four-year period (2007-2010) isolates derived from all patients admitted to infectious diseases ward of Imam Khomeini Hospital, the major referral center for infectious disease in Iran with the highest admission rates, were evaluated. Based on disk diffusion method and zone of inhibition size, the microorganism was regarded as to be sensitive, resistant or has intermediate susceptibility to the antimicrobial agents. RESULTS: The widest spread Gram-negative microorganism in all of isolates taken together in our study was E.coli (30%) followed by Stenotrophomonas maltophilia in 28.6% and Enterobacter spp. in 11.9%, respectively. The susceptibility to amikacin, imipenem, piperacillin/tazobactam, and nitrofurantoin was equal or above 50% for all microorganisms over four years. However, the susceptibility to ampicillin, ampicillin/sulbactam, cefotaxim, and ceftriaxone was less than 50% in derived isolates during the study period. CONCLUSION: In conclusion, the finding of the present study revealed that resistance rate to common antimicrobial agents in Iran is growing and isolates were susceptible mostly to broad-spectrum antibiotics including imipenem and piperacillin/tazobactam.