ABSTRACT
Background: Mupirocin is an antibacterial drug and it is used for topical application either alone or along with other antiseptics, in areas where ever infections or colonization of methicillin-resistant Staphylococcus aureus (MRSA) are found. Enhanced use of mupirocin ointment these days for local application has led to the rise in data of its resistance. Many carriers and patients are treated inappropriately due to lack of sensitivity testing and improper reporting for mupirocin and development of different levels of resistance in these strains. Due to the lack of next level treatment possibilities, we need to report sensitivity accurately, record prevalence of resistant strains, and figure out the cause of resistance. Objective: We carried out this study to demonstrate levels of mupirocin resistance in MRSA strains isolated from patients samples and to check the resistance pattern of these strains to other antibacterial, in our hospital located in Delhi, North India. Materials and Methods: The study is framed as prospective type and performed on the strains of MRSA collected from the different samples from outpatient departments and inpatient departments from January 2017 to December 2017. Out of 221 Staphylococcus aureus collected from different clinical specimens, 113 isolates were confirmed as MRSA strains. Two of the suggested methods were selected to detect mupirocin resistance: Disk diffusion method by 5 μg disc and microbroth dilution method. Results: From our 113 MRSA isolates, resistance for mupirocin was noted in 16 (14.15%) isolates when subjected to disk diffusion and microbroth dilution test. These 16 strains showed varied level of resistance. High-level resistance was shown by 4 (3.5%) isolates and 12 (10.6%) isolates were found as low-level resistant (MuL). Mupirocin resistant MRSA isolates showed higher antibiotic resistance to erythromycin (81.26% vs. 78.76%), clindamycin (56.25% vs. 42.47%), linezolid (12.50% vs. 7.90%), and tigecycline (6.25% vs. 6.19%) as compared to MRSA strains. Not even single MRSA isolates were identified as vancomycin-resistant strain. Conclusion: Both high- and low-level mupirocin-resistant MRSA was found in high numbers from these patients. It is recommended that routine test must be performed to detect resistance for mupirocin subsequent to the detection of MRSA colonization among visitors, patients, and health care workers and its isolation from local sites. Treatment and decolonization of mupirocin-resistant strains are mandatory to reduce infection and spread in hospital after having done proper sensitivity testing only.
ABSTRACT
Resumen En la actualidad, la diseminación de enterobacterias productoras de carbapenemasas se considera un grave problema en clínica debido al fracaso en el tratamiento de las infecciones que ellas producen. Entre las carbapenemasas, la enzima KPC se ha diseminado mundialmente y ha sido identificada en las principales especies de enterobacterias relacionadas con infecciones asociadas a la atención en salud, con claro predominio de Klebsiella pneumoniae a nivel mundial. El gen blaKPC es transportado, principalmente, por el transposón Tn4401, detectado en diversas especies de enterobacterias con distintos secuencio-tipo (ST) y diferente origen geográfico. Adicionalmente, se han descrito nuevas plataformas genéticas que se distinguen del Tn4401 original debido a inserciones y deleciones de otros genes. Los plásmidos que albergan el gen blaKPC pueden ser del tipo conjugativo y no conjugativo movilizable, y además contener otros determinantes genéticos de resistencia. Las cepas productoras de KPC pueden presentar diversos niveles de resistencia a los carbapenémicos, debido a la participación de mecanismos adicionales como diferente grado de expresión de porinas y bombas de expulsión asociados con la producción de β-lactamasas de espectro extendido y/o AmpC. Sin embargo, las carbapenemasas, con KPC como la enzima más frecuente, otorgan grados de resistencia más elevados.
The dissemination of carbapenemase-producing Enterobacteriaceae is currently considered a serious clinical problem due to the failure in the treatment of infections produced by them. Among the carbapenemases, the enzyme KPC has spread worldwide and has been identified in the main enterobacterial species related with healthcareassociated infections, although Klebsiella pneumoniae is the predominant specie. The blaKPC gene is transported, mainly by the transposon Tn4401, detected in various enterobacterial species of different sequence types (ST) and geographical origin. In addition, new genetic platforms that are distinguished, from Tn4401 because of insertions or deletions of other genes have been described. Plasmids containing the blaKPC gene can be conjugative and mobilizable non-conjugative plasmids, and can carry other genetic determinants of resistance. The KPC-producing strains may have different levels of resistance to carbapenems, due to the involvement of additional mechanisms such as different expression levels of porins and efflux pumps associated with the production of extended spectrum β-lactamases and/or AmpC. However, the carbapenemases, with KPC as the most common enzyme, provide higher levels of resistance.