Levofloxacin, as a fluoroquinolone antibacterial drug, has a wide range of antibacterial activities and good tissue penetration ability due to its structural characteristics. In this study, levofloxacin showed significant bactericidal effects against mycoplasma infection, which may be related to its unique mechanism of action. In addition, in this study, the hospital stay time of the observation group was significantly shorter than that of the control group, indicating that BAL local lavage of levofloxacin can help increase the local concentration of the drug at the site of infection, thereby enhancing its antibacterial effect.
In this study, the bronchial lumen of children with RMPP had mucus emboli that could completely block the lumen. The mucosa could necrotize, detach, or ulcerate, and in some cases, cartilage could be damaged or exposed. As a local treatment method, alveolar lavage has the advantage of directly acting on the affected area of the lungs. Through repeated lavage and suction, mucus clots and a large amount of inflammatory secretions can be quickly cleared, reducing local inflammatory reactions and alveolar damage. It helps to block local immune responses, reduce complications and sequelae, shorten the course of the disease, and on the other hand, drugs can be directly delivered to the lesion, reducing the viscosity of the exudate. Moreover, an increase in local drug concentration can effectively exert bactericidal effects. In this study, the recovery time of body temperature, disappearance time of dyspnea, disappearance time of lung moist rales, and hospitalization time of children treated with levofloxacin through bronchoalveolar lavage were significantly shorter than those in the control group. This further confirmed the important role of local application of levofloxacin in improving treatment efficacy in BAL.
Tamura et al. observed the levels of LDH and SF increased in the blood of children with RMPP [9]. There is some studies showing that LDH and SF may be biomarkers for the treatment of RMPP in children [10–11]. In this study, it was found that the LDH and SF of the two groups before treatment were significantly increased, with no significant difference. After treatment, the LDH and SF values of the observation group were significantly lower than those of the control group, indicating that the treatment effect of local levofloxacin in BAL was better than that of the control group.
Inflammatory factors plays a key role in the occurrence, development and prognosis of infectious diseases. In recent years, the research on the pathogenesis of RMPP both domestically and internationally has mainly focused on cell-mediated immune inflammatory responses, and the dynamic balance between various cytokines also plays an important role in maintaining normal immune function in the body [12]. IL-6 is an important mediator of acute phase reactions [13]. Research has shown that MP infection could stimulate the synthesis and release of large amounts of IL-6 from lymphocytes and monocytes, which could promote lymphocyte proliferation and lead to excessive immunity, thereby exacerbating MP infection [14]. IFN -γ is a multifunctional cytokine derived from NK cells that can activate macrophages and destroy pathogens in the early stages. Currently, one study has shown that CT values and the area under the interferon gamma curve have good discriminative power in predicting necrotizing pneumonia (NP) caused by MPP, indicating the involvement of IFN -γ in the progression of MPP [15]. The above studies all suggested that the increase in levels of inflammatory factors such as IL-6 and IFN - γ was related to the severity of pulmonary inflammation caused by infection and mycoplasma infection. In this study, after treatment with levofloxacin, the levels of inflammatory factors in the observation group were significantly lower than those in the control group, indicating that the inflammatory response in the observation group was more effectively suppressed. This may be due to the high concentration of levofloxacin in local application, which can quickly remove lesions and facilitate the drug's better therapeutic effect.
Safety and tolerability are important indicators for evaluating new treatment options. In this study, minor adverse events of levofloxacin were alleviated by symptomatic treatment, and no serious adverse events occurred in either group, indicating that the treatment regimen has good safety and tolerability. According to reports, there were no clinically detectable adverse events for up to 5 years after treatment with levofloxacin [16]. Although there is still a lack of information on its safety in children, the European and American versions of quinolone drugs have instructions for children's use, and such drugs may have adverse effects on children's growth and development [17–18]. However, no side effects such as cartilage injury, tendon disease, and arthritis were observed in this study. However, due to the short follow-up time, further follow-up is still required.