Background: Epidemiologic studies show the high prevalence of some infections and cancers in individual blood groups. Perhaps, level of immunity factors differs in people with individual blood group. The aim of this study is to compare the level of antibodies and complement factors in ABO blood groups.

Materials and Methods: In this descriptive study, peripheral blood samples from 40 male healthy individuals with different ABO blood groups (n=10 in each group) with similar age (18-25 years) and genetic background were collected. The serum levels of total IgG, IgM, IgA, C3, and C4 were analyzed by nephelometry method. All data were analyzed by SPSS software version 11.5.

Results: The levels of IgA, IgG, and C4 protein in individuals with O blood group were significantly higher than those of other groups (p=0.02, p=0.01, and p=0.004, respectively). Also, the mean concentration of IgM in individuals with AB blood group was significantly higher than that in other groups (p=0.02). There was a significant difference between the level of C3 in O blood group and those of other blood groups (p=0.01). The mean concentrations of all parameters (except IgG) in B blood group were lower than those in other blood group.

Conclusion: Generally, natural antibodies in O blood group were higher than those in other groups. This high level of total antibodies in O blood group may reduce susceptibility to some infections.

Background: According to the studies, Iran’s per capita antibiotic consumption is remarkable. Since the emergence of Antibiotic Resistant Organisms (AROs) is considered a global problem in the community and hospitals, this study aimed to investigate the pattern of antibiotic resistance in Gram-negative bacteria isolated from patients in an academic and a non-academic hospital in Arak, Iran.

Materials and Methods: This descriptive cross-sectional study included all specimens referred to the microbiology laboratory at Amir Al-Momenin Hospital (academic hospital) and Imam Khomeini Hospital (non-academic hospital) in a one-year period from June 2012 to June 2013. The susceptibility of the isolated Gram-negative bacteria against the important antibiotics used in clinical practice was determined using the disk diffusion method.

Results: A total of 846 specimens were collected from patients in the two hospitals where 520 (61.5%) were Gram-negative bacteria, of which 63.3% were E. coli. The prevalence of Gram-negative organisms in the academic and the non-academic hospital was measured 79.8% and 20.2%, respectively (p=0.097). It was also determined that there is a significant difference between the two hospitals in the prevalence of ESBL (Extended-Spectrum Beta-Lactamase) Gram-negative bacteria (p=0.003).

Conclusion: There was a significant difference between the two hospitals in the prevalence of ESBL Gram-negative bacteria. Therefore, conducting regional surveillance programs to examine the patterns of antibiotic resistance is recommended.