Anane Yaw Adjei, Apalata Teke, Vasaikar Sandeep, Okuthe Grace Emily, Songca Sandile Phinda
Division of Medical Microbiology, Department of Laboratory Medicine and Pathology, Faculty of Health Sciences, Walter Sisulu University, Private Bag: X1, Mthatha, 5117 Eastern Cape Province, South Africa.
Division of Medical Microbiology, Department of Laboratory Medicine and Pathology, Faculty of Health Sciences, Walter Sisulu University, Private Bag: X1, Mthatha, 5117 Eastern Cape Province, South Africa; Division of Medical Microbiology, National Health Laboratory Services (NHLS), Nelson Mandela Central Hospital, Mthatha 5100, South Africa.
Photodiagnosis Photodyn Ther. 2020 Jun;30:101752. doi: 10.1016/j.pdpdt.2020.101752. Epub 2020 Apr 11.
Acinetobacter baumannii is a challenging pathogen due to the rapid development of antimicrobial resistance and biofilm formation. The objective of this study was to evaluate the effect of antimicrobial photodynamic inactivation against biofilms of multidrug-resistant A. baumannii isolated from clinical, abattoir and aquatic sources.
The isolates were tested for susceptibility to imipenem, meropenem, tigecycline and colistin using autoSCAN-4 automated system and rechecked by the E-test. Methylene blue, Protoporphyrin IX, and a halogen lamp were used in the in vitro assay against biofilms of the isolates. The antimicrobial photodynamic inactivation was assessed by counting colony-forming units (CFU).
The isolates from abattoir and aquatic sources were resistant to carbapenems (>64 μg/mL) but susceptible to tigecycline (2 μg/mL) and colistin (Abattoir, 0.35 μg/mL and Aquatic, 0.24 μg/mL), whereas the clinical isolate was susceptible to only colistin (0.5 μg/mL) using the E-test. The log survival percentages of the control group at a concentration of 20 μM were 5 × 10 % for Protoporphyrin IX and 2 × 10 % for Methylene blue. Therefore, Methylene blue showed higher bacterial reduction of 7.0 log colony forming units than 6.0 log for Protoporphyrin IX. No significant difference was observed with respect to the origin of isolates and the minimum inhibitory concentrations.
The results indicate that antimicrobial photodynamic inactivation could be an alternative strategy for the control of infections caused by multi-drug resistant A. baumannii by significantly reducing biofilm growth at a sub-lethal concentrations.
鲍曼不动杆菌是一种具有挑战性的病原体，因其抗菌耐药性的快速发展和生物膜形成。本研究的目的是评估抗菌光动力灭活对从临床、屠宰场和水源分离的多重耐药鲍曼不动杆菌生物膜的影响。
使用autoSCAN-4自动化系统检测分离株对亚胺培南、美罗培南、替加环素和黏菌素的敏感性，并通过E-test重新检查。在体外试验中，使用亚甲蓝、原卟啉IX和卤素灯对抗分离株的生物膜。通过计算菌落形成单位（CFU）评估抗菌光动力灭活。
屠宰场和水源分离株对碳青霉烯类耐药（>64μg/mL），但对替加环素（2μg/mL）和黏菌素敏感（屠宰场，0.35μg/mL；水源，0.24μg/mL），而临床分离株使用E-test仅对黏菌素敏感（0.5μg/mL）。对照组在浓度为20μM时，原卟啉IX的对数存活百分比为5×10%，亚甲蓝为2×10%。因此，亚甲蓝显示出比原卟啉IX更高的细菌减少率，为7.0个对数菌落形成单位，而原卟啉IX为6.0个对数。在分离株的来源和最低抑菌浓度方面未观察到显著差异。
结果表明，抗菌光动力灭活可能是控制多重耐药鲍曼不动杆菌引起的感染的一种替代策略，通过在亚致死浓度下显著减少生物膜生长。
