Tashakori Mahnaz, Mohseni Moghadam Fateme, Ziasheikholeslami Nazanin, Jafarpour Parvin, Behsoun Maryam, Hadavi Maryam, Gomreei Mohammadhossein
Department of Paramedical Laboratory Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran.
Department of Infectious Diseases, Qom University of Medical Sciences, Qom, Iran.
Iran J Microbiol. 2014 Apr;6(2):79-83.
Staphylococcus aureus is an important infection in hemodialysis patients. We studied the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) and its antibiotic resistance pattern in patients receiving hemodialysis as well as in dialysis unit staff.
From June to September 2012, we evaluated 74 cases including 61 patients on hemodialysis and 13 dialysis unit staff. Nasal swabs were taken from all cases and were cultured on a blood medium agar. We identified S. aureus based on conventional laboratory methods. For antimicrobial resistance patterns, we used disk diffusion method. Oxacillin MIC, oxacillin and cefoxcitin disk diffusion methods were used for detection of MRSA. Disk approximation test (D-test) was applied for the frequency of erythromycin induced clindamycin resistance.
S. aureus carrier state was determined in 12 of the 61 patients on hemodialysis (19.67%) and 5 of the 13 dialysis unit staffs (38.46%). In hemodialyzed patients, MRSA and MSSA carrier of S. aureus were 6.56% and 13.11%, respectively. All nasal carriage states in studied staffs were MSSA. All isolated S. aureus were found to be sensitive to vancomycin, teicoplanin, and rifampin. However, reduced sensitivity of MRSA isolates to other antibiotics was noted. Resistance frequencies to tested antibiotic was as follows: cefteriaxone and penicillin (100%), tetracycline and doxycilin (75%), gentamicin, cloxacillin, and cefazolin (50%), ciprofloxacin, trimethoprim-sulfamethoxazol, erythromycin, and clindamycin (25%). The resistance rate of isolated MSSA against tested antibiotics was lower than isolated MRSA. Inducible clindamycin resistance was shown in 25% of identified MRSA strains.
S. aureus nasal carrier state was lower than former reports from other parts of Iran. The antibiotic resistance patterns also differed, perhaps due to different pattern of administering antibiotics at our hospital. Screening of these patients should be noted as a health priority and microbial sensitivity tests should be considered in order to optimize treatment options.
金黄色葡萄球菌是血液透析患者的一种重要感染源。我们研究了接受血液透析的患者以及透析单位工作人员中耐甲氧西林金黄色葡萄球菌（MRSA）的鼻腔携带率及其抗生素耐药模式。
2012年6月至9月，我们评估了74例病例，其中包括61例接受血液透析的患者和13名透析单位工作人员。对所有病例采集鼻拭子，并在血琼脂培养基上进行培养。我们根据传统实验室方法鉴定金黄色葡萄球菌。对于抗菌药物耐药模式，我们采用纸片扩散法。使用苯唑西林MIC、苯唑西林和头孢西丁纸片扩散法检测MRSA。应用纸片扩散试验（D试验）检测红霉素诱导的克林霉素耐药频率。
61例接受血液透析的患者中有12例（19.67%）检测到金黄色葡萄球菌携带状态，13名透析单位工作人员中有5例（38.46%）检测到。在血液透析患者中，金黄色葡萄球菌的MRSA和MSSA携带者分别为6.56%和13.11%。研究的工作人员中所有鼻腔携带状态均为MSSA。所有分离出的金黄色葡萄球菌均对万古霉素、替考拉宁和利福平敏感。然而，注意到MRSA分离株对其他抗生素的敏感性降低。对所测试抗生素的耐药频率如下：头孢曲松和青霉素（100%）、四环素和强力霉素（75%）、庆大霉素、氯唑西林和头孢唑林（50%）、环丙沙星、复方新诺明、红霉素和克林霉素（25%）。分离出的MSSA对所测试抗生素的耐药率低于分离出的MRSA。在鉴定出的MRSA菌株中，25%显示出诱导性克林霉素耐药。
金黄色葡萄球菌鼻腔携带状态低于伊朗其他地区以前的报告。抗生素耐药模式也有所不同，这可能是由于我们医院抗生素给药模式不同所致。应将对这些患者的筛查作为卫生优先事项，并应考虑进行微生物敏感性试验以优化治疗方案。
