ABSTRACT
Objectives: Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride [BAC], benzethonium chloride [BZT], and chlorhexidine digluconate [CHDG] among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci [CoNS]
Methods: The minimum inhibitory concentration [MIC] of 60 methicillin-resistant S. aureus [MRSA], 54 methicillin-sensitive S. aureus [MSSA] and 51 CoNS isolates from a single hospital to three biocidal agents [BAC, BZT, and CHDG] was determined. Biocide resistance genes [qacA/B, smr, qacG, qacH, qacJ, and norA] were analyzed by the polymerase chain reaction assay
Results: All isolates had MICs for BAC and BZT from 0.25 to 8 microg/mL, and for CHDG from 0.5 to 64 microg/mL. qacA/B was the most common biocide resistance gene among all 165 Staphylococcus isolates [76; 46%], which comprised 38 [63.3%] MRSA, 14 [25.9%] MSSA, and 24 [47%] CoNS. Eleven [6.7%] and 24 [14.5%] isolates among the 165 Staphylococci carried smr and norA genes, respectively. In contrast, other resistance genes such as qacG, qacH, and qacJ were absent in all Staphylococci studied. The qacA/B and smr genes were detected concomitantly in 3% of isolates, and 23.6% strains of the total 165 Staphylococcus isolates were negative for each studied gene
Conclusions: The carriage of several biocide resistance genes, including qacA/B, smr, and norA, alone or concurrently, is associated with reduced susceptibility. Use of antiseptics may select for antibiotic-resistant strains and assist their survival in the healthcare environment
ABSTRACT
The appendix is considered as part of the gut-associated lymphoid tissue; however, lymphocyte subsets in this tissue are not fully defined. To investigate and compare the function and phenotype of lymphocyte subsets in peripheral blood and appendix of patients with normal and inflamed appendix tissues. Peripheral blood samples and appendiceal mononuclear cells were obtained from 81 patients [mean age; 23 +/- 10.5 years], clinically suspected of having appendicitis. The phenotypic characteristics of lymphocyte subsets in peripheral blood [before and 48-72 hrs after appendectomy] and in appendix tissue were analyzed by three color-flow cytometry. The proliferative response of mononuclear cells was assessed by MTT method. The frequency of CD19+DR+, HLA-DR+ and CD19+ cells in the appendix tissue were significantly higher than that of the peripheral blood in all the groups [p<0.001]. The percentage of CD19+ cells and HLA-DR+CD19+ cells significantly decreased after appendectomy in the peripheral blood of the patients with acute appendicitis [p=0.047 and p=0.03, respectively]. CD19 and HLA-DR plus CD19 had better diagnostic efficiency compared with T cell markers [area under the ROC curve [AUC]= 0.76 and 0.73, respectively]. These results indicate a significant difference in CD19+ and HLA-DR+ lymphocytes between peripheral blood and the appendix tissue.