Premanand Bavani, Thiyagarajan Sabarinathan, Thangavelu Swarnalingam, Mohammed Ali Saleem, George Fatima Shirly Anitha
Microbiology, Melmaruvathur Adhiparasakthi Institute of Medical Sciences and Research, Chengalpattu, IND.
Anesthesiology and Critical Care, Melmaruvathur Adhiparasakthi Institute of Medical Sciences and Research, Chengalpattu, IND.
Cureus. 2023 Oct 3;15(10):e46435. doi: 10.7759/cureus.46435. eCollection 2023 Oct.
Nasal carriage of species plays an important role in the epidemiology and pathogenesis of both community and healthcare-associated infections. Coinciding the emergence of methicillin-resistant (MRSA) is a challenge for clinicians to prevent their spread. Mupirocin is a topical antimicrobial agent approved for eradicating nasal carriage of staphylococcal species in adult patients and healthcare workers (HCWs). The increasing prevalence of mupirocin resistance among and coagulase-negative staphylococci species could be an important threat to the future use of mupirocin against MRSA.
The aim of this study is to determine the prevalence of MRSA from nasal swabs of HCWs in intensive care units and its level of resistance pattern of mupirocin in all isolates of species by disk diffusion and epsilometer test (E-test) and to determine post decolonization screening.
A total of 67 HCWs (doctors, nursing staff, technicians, and housekeeping staff) in the medical and surgical intensive care units were included in the study. Nasal swabs were collected from the subjects and cultured onto nutrient and blood agar, which were then incubated at 37ºC for 18 to 24 hours. and coagulase-negative species (CoNS) were identified by standard biochemical techniques. Methicillin resistance was detected by the disk diffusion method using a 30 µg cefoxitin disk as per the Clinical and Laboratory Standards Institute (CLSI) guidelines, and mupirocin resistance was detected using a 5 µg mupirocin disk. The resistance strains were further subjected to E-strip testing to determine the level of mupirocin resistance.
A total of 72 isolates were grown from the 67 subjects used in this study. Nine strains (12.5%) grew and 52 strains (72.2%) grew CoNS. Methicillin resistance was seen in five isolates (6.9%) of and 45 isolates (62.5%) of CoNS. Mupirocin resistance was seen in 11 isolates of methicillin-resistant coagulase-negative species (MRCoNS), where three isolates (4.1%) showed low-level mupirocin resistance MuL and eight isolates (11.11%) showed high-level mupirocin resistance MuH. None of the isolates of MRSA, methicillin-sensitive (MSSA), and methicillin-sensitive coagulase-negative species (MSCoNS) were resistant to mupirocin. Seven out of nine HCWs (77.8%) showed clearance of the organism after decolonization therapy.
The prevalence of emerging resistance to mupirocin in MRSA and MRCoNS is of great concern, especially in the nasal carrier state of HCWs. Hence, methicillin and mupirocin resistance in and CoNS must be detected in HCWs as a routine protocol, and decolonization measures should be undertaken to prevent healthcare-associated infections.
某种细菌的鼻腔定植在社区感染和医疗保健相关感染的流行病学及发病机制中起着重要作用。耐甲氧西林该种细菌（MRSA）的出现给临床医生预防其传播带来了挑战。莫匹罗星是一种局部用抗菌剂，已被批准用于根除成年患者和医护人员鼻腔中的葡萄球菌属细菌。葡萄球菌属和凝固酶阴性葡萄球菌中莫匹罗星耐药性的日益普遍可能对未来使用莫匹罗星对抗MRSA构成重大威胁。
本研究旨在通过纸片扩散法和梯度稀释法（E-test）确定重症监护病房医护人员鼻拭子中MRSA的流行情况及其在所有葡萄球菌属分离株中莫匹罗星的耐药模式，并进行去定植后的筛查。
本研究共纳入了67名医疗和外科重症监护病房的医护人员（医生、护理人员、技术人员和后勤人员）。从受试者采集鼻拭子并接种到营养琼脂和血琼脂上，然后在37℃下培养18至24小时。通过标准生化技术鉴定葡萄球菌属和凝固酶阴性菌（CoNS）。根据临床和实验室标准协会（CLSI）指南，使用30μg头孢西丁纸片通过纸片扩散法检测耐甲氧西林情况，使用5μg莫匹罗星纸片检测莫匹罗星耐药性。对耐药菌株进一步进行E试纸条检测以确定莫匹罗星的耐药水平。
本研究中使用的67名受试者共培养出72株分离株。9株（12.5%）为葡萄球菌属生长菌株，52株（72.2%）为CoNS生长菌株。在5株（6.9%）葡萄球菌属和45株（62.5%）CoNS中发现了耐甲氧西林情况。在11株耐甲氧西林凝固酶阴性葡萄球菌（MRCoNS）中发现了莫匹罗星耐药性，其中3株（4.1%）表现为低水平莫匹罗星耐药MuL，8株（11.11%）表现为高水平莫匹罗星耐药MuH。MRSA、甲氧西林敏感葡萄球菌（MSSA）和甲氧西林敏感凝固酶阴性菌（MSCoNS）的分离株均未对莫匹罗星耐药。9名医护人员中有7名（77.8%）在去定植治疗后显示细菌清除。
MRSA和MRCoNS中莫匹罗星新出现的耐药性流行情况令人高度担忧，尤其是在医护人员的鼻腔携带状态下。因此，应将检测医护人员中葡萄球菌属和CoNS的甲氧西林和莫匹罗星耐药性作为常规方案，并应采取去定植措施以预防医疗保健相关感染。
