Killing kinetics of minocycline, doxycycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae

Effectiveness and safety of tetracyclines and quinolones in people with Mycoplasma pneumonia: a systematic review and network meta-analysis

Background

The escalating resistance of Mycoplasma pneumoniae to macrolides has become a significant global health concern, particularly in low-income and middle-income countries (LMICs). Although tetracyclines and quinolones have been proposed as alternative therapeutic options, concerns regarding age-specific safety issues and the lack of consensus in recommendations across various national guidelines prevail. Thus, the primary objective of this study is to ascertain the most efficacious interventions for second-line treatment of M. pneumoniae infection while considering the age-specific safety issues associated with these interventions.

Methods

In this systematic review and network meta-analysis we searched PubMed, Embase, CNKI, and WanFang Data, from inception up to November 11th, 2023. Studies of quinolones or tetracyclines for the treatment of people with M. pneumoniae infection were collected and screened by reading published reports, with any type of study included, and no individual patient-level data requested. A systematic review and direct meta-analysis compared the efficacy of tetracyclines and quinolones regarding time to defervescence (TTD) and the rates of fever disappearance within 24 h and 48 h of antibiotic administration, for managing M. pneumoniae infection. Bayesian network meta-analysis (NMA) was employed to indirectly assess the relative effectiveness of different interventions in people with M. pneumoniae infection and the safety profile of medication in paediatric patients. This study is registered with PROSPERO, CRD42023478383.

Findings

The systematic review and direct meta-analysis included a total of 4 articles involving 246 patients, while the NMA encompassed 85 articles involving a substantial cohort of 7095 patients. The NMA measured the effectiveness across all ages and included 7043 patients, with a mean age of 37.80 ± 3.91 years. Of the 85 included studies, 14 (16.5%) were at low risk of bias, 71 (83.5%) were at moderate risk, and no studies were rated as having a high risk of bias. In the direct meta-analysis, no statistically significant differences were found between tetracyclines and quinolones concerning TTD (mean difference: -0.40, 95% CI: -1.43 to 0.63; I2 = 0%), fever disappearance rate within 24 h of antibiotic administration (OR: 0.37, 95% CI: 0.08-1.79; I2 = 58%), and fever disappearance rate within 48 h of antibiotic administration (OR: 1.10, 95% CI: 0.30-3.98; I2 = 59%). However, the comprehensive NMA analysis of clinical response (in 70 studies; n = 6143 patients), shortening of TTD (in 52 studies; n = 4363 patients), shortening length of cough relief or disappearance (in 39 studies; n = 3235 patients), fever disappearance rate at 48 h (in four studies; n = 418 patients) revealed that minocycline exhibited the most favourable outcomes across these various parameters, and the analysis of fever disappearance rate at 24 h (in three studies; n = 145 patients) revealed that levofloxacin may be the most effective, as indicated by the rank probabilities and surface under the cumulative ranking area (SUCRA) value. Moxifloxacin ranked second in clinical response and in shortening the length of cough relief or disappearance, and third in shortening TTD. Notably, when evaluating the occurrence of adverse reactions in paediatric patients (in four studies; n = 239 children), levofloxacin was associated with the highest SUCRA value rankings for the rate of adverse events.

Interpretation

Our findings suggest that tetracyclines and quinolones may be equally effective. Based on the age of participants in the included studies, minocycline may be the most effective intervention for children over eight years of age when all preventive measures are considered, whereas moxifloxacin may benefit people under eight years of age. However, these results should be interpreted with caution, given the limited number of studies and patients included, and the heterogeneity between included studies. Based on a limited number of studies in children, levofloxacin is likely to have one of the highest rates of adverse reactions. The majority of the studies included in the NMA were from the Asian region, and more randomised controlled trials comparing different therapeutic strategies in patients with M. pneumoniae are warranted. This comparative study provides clinical pharmacists and clinicians with important information to enable them to make informed decisions about treatment options, considering drug efficacy and safety.

Funding

The Natural Science Foundation of Fujian Province, China.

Challenges in the treatment of pediatric Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is an important cause of community-acquired pneumonia in children and young adolescents. Despite macrolide antibiotics effectiveness as a first-line therapy, persistence of fever and/or clinical deterioration sometimes may complicate treatment and may even lead to severe systemic disease. To date, there is no consensus on alternative treatment options, optimal dosage, and duration for treating severe, progressive, and systemic MP pneumonia after macrolide treatment failure. Macrolide-resistant MP pneumonia and refractory MP pneumonia are the two major complex conditions that are clinically encountered. Currently, the vast majority of MP isolates are resistant to macrolides in East Asia, especially China, whereas in Europe and North America, whereas in Europe and North America prevalence is substantially lower than in Asia, varying across countries. The severity of pneumonia and extrapulmonary presentations may reflect the intensity of the host's immune reaction or the dissemination of bacterial infection. Children infected with macrolide-resistant MP strains who receive macrolide treatment experience persistent fever with extended antibiotic therapy and minimal decrease in MP-DNA load. Alternative second-line agents such as tetracyclines (doxycycline or minocycline) and fluoroquinolones (ciprofloxacin or levofloxacin) may lead to clinical improvement after macrolide treatment failure in children. Refractory MP pneumonia reflects a deterioration of clinical and radiological findings due to excessive immune response against the infection. Immunomodulators such as corticosteroids and intravenous immunoglobulin (IVIG) have shown promising results in treatment of refractory MP pneumonia, particularly when combined with appropriate antimicrobials. Corticosteroid-resistant hyperinflammatory MP pneumonia represents a persistent or recrudescent fever despite corticosteroid therapy with intravenous methylprednisolone at standard dosage.

CONCLUSION

 This report summarizes the clinical significance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drugs, with a stepwise approach to the management of MP pneumonia recommended from the viewpoint of clinical practice.

WHAT IS KNOWN

• Although MP pneumonia is usually a benign self-limited infection with response macrolides as first line therapy, severe life-threatening cases may develop if additional treatment strategies are not effectively implemented. • Macrolide-resistant and refractory MP pneumonia are two conditions that may complicate the clinical course of MP pneumonia, increasing the risk for exacerbation and even death.

WHAT IS NEW

• This report summarizes the clinical relevance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drug therapies. • A practical stepwise approach to the management of MP pneumonia is developed based on a comprehensive analysis of existing evidence and expert opinion.

In vitro pharmacodynamics of nemonoxacin and other antimicrobial agents against Mycoplasma pneumoniae

IMPORTANCE

This study first reported the in vitro effector kinetics of the new non-fluorinated quinolone, nemonoxacin, against macrolide-resistant M. pneumoniae (MRMP) and macrolide susceptible M. pneumoniae (MSMP) strains along with other antimicrobial agents. The time-kill assays and pharmacodynamic analysis showed that nemonoxacin has significant mycoplasmacidal activity against MRMP and MSMP. This study paves the road to establish appropriate dosing protocols of a new antimicrobial drug for children infected with M. pneumoniae.

The efficacy and safety of minocycline as adjuvant therapy in refractory mycoplasma pneumonia in Chinese children: a meta-analysis

Background

To explore the efficacy and safety of minocycline as adjuvant therapy for refractory mycoplasma pneumonia in Chinese children.

Methods

PubMed, EMBASE, Cochrane Library, CNKI, Wanfang database and VIP database were systematically searched. Studies where minocycline was used as adjuvant therapy for refractory mycoplasma pneumonia in Chinese children were included. The effect of numeration data and the measurement data were represented by odds ratios (OR) and weighted mean differences (MD), respectively. Review Manager version 5.3 was used to compare the treatment efficacy, time for the cough to subside, defervescence time, hospitalisation time, adverse events and other indicators.

Results

Ten studies involving 857 patients were included in the final analysis. Compared with the conventional treatment of refractory mycoplasma pneumonia in children, the addition of minocycline as adjuvant therapy was found to improve the treatment efficacy (OR: 5.45; 95% CI: 3.46, 8.57, p < 0.001); shorten the duration of cough (MD: -3.61; 95%CI: -4.25, -2.97, p < 0.001), fever time (MD: -4.77; 95% CI: -6.30, -3.23, p < 0.001) and hospitalisation time (MD: -5.53 (95% CI: -7.19, -3.88, p < 0.001); and decrease the concentration of C-reactive protein (MD: -13.95; 95%CI: -18.61, -9.29; p < 0.001) and the erythrocyte sedimentation rate (MD: -10.88; 95% CI: -14.05, -7.72, p < 0.001). The use of minocycline did not lead to significant adverse events (OR = 0.63; 95% CI: 0.39, 1.01, p = 0.05).

Conclusion

The use of minocycline as adjuvant treatment of refractory mycoplasma pneumonia in Chinese children has good efficacy and safety and may be promoted in clinical practice.

Polymyxin B Combined with Minocycline: A Potentially Effective Combination against blaOXA-23-harboring CRAB in In Vitro PK/PD Model

Polymyxin-based combination therapy is commonly used to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections. In the present study, the bactericidal effect of polymyxin B and minocycline combination was tested in three CRAB strains containing bla_OXA-23 by the checkerboard assay and in vitro dynamic pharmacokinetics/pharmacodynamics (PK/PD) model. The combination showed synergistic or partial synergistic effect (fractional inhibitory concentration index ≤0.56) on the tested strains in checkboard assays. The antibacterial activity was enhanced in the combination group compared with either monotherapy in in vitro PK/PD model. The combination regimen (simultaneous infusion of 0.75 mg/kg polymyxin B and 100 mg minocycline via 2 h infusion) reduced bacterial colony counts by 0.9–3.5 log₁₀ colony forming units per milliliter (CFU/mL) compared with either drug alone at 24 h. In conclusion, 0.75 mg/kg polymyxin B combined with 100 mg minocycline via 2 h infusion could be a promising treatment option for CRAB bloodstream infections.

Effects of minocycline on macrolide-unresponsive Mycoplasma pneumoniae pneumonia in children: a single-center retrospective study

BACKGROUND

Macrolide-resistant Mycoplasma pneumoniae (Mp) has become widespread in the world. We sought to determine the independently associated risk factors for refractory Mp pneumonia among macrolide-unresponsive Mp pneumonia children treated with minocycline and to investigate the effects of minocycline against macrolide-unresponsive Mp pneumonia.

METHODS

In our center, we retrospectively analyzed the data of hospitalized macrolide-unresponsive Mp pneumonia patients aged ≤18 years old who changed macrolide therapies to minocycline treatments between March 2013 and September 2018. Patient characteristics and defervescence after minocycline treatment were compared between refractory Mp pneumonia and non-refractory Mp pneumonia groups. Multivariable logistic regression analysis was performed among these macrolide-unresponsive Mp pneumonia patients.

RESULTS

Among 150 included macrolide-unresponsive Mp pneumonia children treated with minocycline; 30 cases (20.0%) were refractory Mp pneumonia. Duration of macrolide treatment before administration of minocycline (odds ratio =2.87, 95% CI: 1.79-4.61, P<0.001) and serum procalcitonin levels (odds ratio =13.50, 95% CI: 1.22-149.57, P=0.034) were independently associated with refractory Mp pneumonia. Defervescence after minocycline treatment was significantly longer among the refractory Mp pneumonia group than in the non-refractory Mp pneumonia group (median 2 vs. 1 day, P<0.001). Only one case (0.7%) suspected of a side effect of minocycline therapy was observed.

CONCLUSIONS

Two risk factors independently associated with refractory Mp pneumonia were determined. Early use of minocycline might safely prevent macrolide-unresponsive Mp pneumonia from progressing to refractory Mp pneumonia.

Clinical Evaluation of a Novel Point-of-Care Assay To Detect Mycoplasma pneumoniae and Associated Macrolide-Resistant Mutations

The recent increase in macrolide-resistant Mycoplasma pneumoniae in Asia has become a continuing problem. A point-of-care testing method that can quickly detect M. pneumoniae and macrolide-resistant mutations (MR mutations) is critical for proper antimicrobial use. Smart Gene (Mizuho Medy Co., Ltd., Tosu City, Saga, Japan) is a compact and inexpensive fully automatic gene analyzer that combines amplification with PCR and the quenching probe method to specify the gene and MR mutations simultaneously. We performed a clinical evaluation of this device and its reagents on pediatric patients with suspected M. pneumoniae respiratory infections and evaluated the impact of the assay on antimicrobial selection. Using real-time PCR as a comparison control, the sensitivity of Smart Gene was 97.8% (44/45), its specificity was 93.3% (98/105), and its overall concordance rate was 94.7% (142/150). The overall concordance rate of Smart Gene diagnosis of MR mutations in comparison with sequence analysis was 100% (48/48). The ratio of MR mutations was significantly higher at high-level medical institutions than at a primary medical clinic (P = 0.023), and changes in antibiotic therapy to drugs other than macrolides were significantly more common in patients with MR mutations (P = 0.00024). Smart Gene demonstrated excellent utility in the diagnosis of M. pneumoniae and the selection of appropriate antimicrobials for MR mutations at primary medical institutions, which play a central role in community-acquired pneumonia care. The use of this device may reduce referrals to high-level medical institutions for respiratory infections, thereby reducing the medical and economic burdens on patients.

Benefits and risks of therapeutic alternatives for macrolide resistant Mycoplasma pneumoniae pneumonia in children

Although Mycoplasma pneumoniae pneumonia (MPP) has been generally susceptible to macrolides, the emergence of macrolide-resistant MPP (MRMP) has made its treatment challenging. MRMP rapidly spread after the 2000s, especially in East Asia. MRMP is more common in children and adolescents than in adults, which is likely related to the frequent use of macrolides for treating M. pneumoniae infections in children. MRMP is unlikely to be related to clinical, laboratory, or radiological severity, although it likely prolongs the persistence of symptoms and the length of hospital stay. Thereby, it causes an increased burden of the disease and poor quality of life for the patient as well as a societal socioeconomic burden. To date, the only alternative treatments for MRMP are secondary antimicrobials such as tetracyclines (TCs) or fluoroquinolones (FQs) or systemic corticosteroids; however, the former are contraindicated in children because of concerns about potential adverse events (i.e., tooth discoloration or tendinopathy). A few guidelines recommended TCs or FQs as the second-line drug of choice for treating MRMP. However, there have been no evidence-based guidelines. Furthermore, safety issues have not yet been resolved. Therefore, this article aimed to review the benefits and risks of therapeutic alternatives for treating MRMP in children and review the recommendations of international or regional guidelines and specific considerations for their practical application.

Emergence of Haemophilus influenzae with low susceptibility to quinolones and persistence in tosufloxacin treatment

BACKGROUND

The use of non-β-lactam agents has increased in Japan due to the prevalence of β-lactam-resistant pathogens. This study aimed to clarify the recent trend of antimicrobial susceptibility and molecular epidemiological features in Haemophilus influenzae.

METHODS

Fifty-seven Haemophilus influenzae isolated from a Japanese teaching hospital in 2017 were characterised, and the data were compared with those of a previous study. The MICs were determined using the broth dilution method. Genetic backgrounds were compared by multilocus sequence typing. The bactericidal activity of tosufloxacin at, or near, the therapeutic Cmax was determined in vitro, with susceptible isolates and quinolone low-susceptible isolates by time-kill assay.

RESULTS

The results of the susceptibility tests showed that >90% of isolates were susceptible to cephalosporins and carbapenems, whereas ampicillin-susceptible and clarithromycin-susceptible isolates decreased. Regarding quinolones, low-susceptible isolates were noted in 2017, although all isolates were judged as susceptible. All low-susceptible isolates had an amino acid substitution in GyrA, and two isolates had an additional substitution in ParC. These isolates had different genetic backgrounds. Furthermore, the time-kill kinetic assay using the Cmax of tosufloxacin indicated that the low-susceptible isolates could persist for at least 8hours.

CONCLUSIONS

This study revealed that Haemophilus influenzae has demonstrated multidrug low-susceptibility in recent years. The low-susceptible isolates had genetic diversity, meaning that resistance occurred independently.

Clinical features and seasonal variations in the prevalence of macrolide-resistant Mycoplasma pneumoniae

BACKGROUND

Mycoplasma pneumoniae is a common pathogen causing pneumonia; macrolide-resistant strains are rapidly spreading across Japan. However, the clinical features of macrolide-resistant M. pneumoniae pneumonia have not been well established. Here, we evaluated the clinical characteristics and seasonal variations in the prevalence of M. pneumoniae with macrolide-resistant mutations (MRM).

METHODS

The monthly prevalence of MRM in M. pneumoniae strains isolated from May 2016 to April 2017 was retrospectively analyzed, and the clinical characteristics of pneumonia cases with MRM were compared to those of cases without MRM. The M. pneumoniae isolates and point mutations at site 2063 or 2064 in domain V of 23S rRNA were evaluated by the GENECUBE system and GENECUBE Mycoplasma detection kit.

RESULTS

Mycoplasma pneumoniae infection was identified in 383 cases, including 221 cases of MRM (57.7%). The MRM prevalence was 86.3% (44/51) between May and July 2016, demonstrating an apparent decrease in September 2016, subsequently reaching 43.0% (34/79) in November 2016. Mycoplasma pneumoniae pneumonia was diagnosed in 275 cases, including 222 pediatric and 53 adult cases. Macrolide use preceding evaluation was found to be the only feature of MRM pneumonia cases both in children (odds ratio [OR] 3.86, 95% confidence interval [CI]:1.72-8.66) and in adults (OR 7.43, 95% CI: 1.67-33.1).

CONCLUSIONS

The determination rate of MRM varied widely throughout the year, and our study demonstrated the challenges in predicting M. pneumoniae with MRM based on clinical features at diagnosis. Therefore, continuous monitoring of the prevalence of MRM is warranted, which may help in selecting an effective treatment.