In vitro efficacy of combinations of eight antimicrobial agents against Mycobacteroides abscessus complex

In vitro antimicrobial activity of doxycycline, minocycline, and tigecycline against Mycobacterium abscessus complex: A meta-analysis study

PURPOSE

Mycobacterium abscessus complex (MABC) infections are increasing worldwide. Furthermore, these infections have a low treatment success rate due to their resistance to many current antibiotics. This study aimed to determine the overall in vitro activity of the tetracyclines doxycycline (DOX), minocycline (MIN), and tigecycline (TGC) against MABC clinical isolates.

PATIENTS AND METHODS

A systematic review of PubMed/MEDLINE, Web of Science, and Embase was conducted up to August 28, 2023. Studies applying the drug susceptibility testing standards of the Clinical and Laboratory Standards Institute were considered. A random effects model was used to assess the total in vitro resistance rates of the MABC clinical isolates to DOX, MIN, and TGC. The I2 and Cochran's Q statistics were employed to evaluate the origins of heterogeneity. All analyses were conducted using CMA V.3 software.

RESULTS

Twenty-six publications (22, 12, and 11 studies on DOX, MIN, and TGC, respectively) were included. The pooled in vitro resistance rates of the MABC clinical isolates to DOX and MIN at the breakpoint of 8 μg/mL were 93.0 % (95 % CI, 89.2 %-95.5 %) and 87.2 % (95 % CI, 76.5 %-93.4 %), respectively. In the case of TGC, the breakpoints of 2, 4, and 8 μg/mL were associated with pooled resistance rates of 2.5 % (95 % CI, 0.5 %-11.6 %), 7.2 % (95 % CI, 4.0 %-12.5 %), and 16.8 % (95 % CI, 4.7 %-45.0 %), respectively.

CONCLUSION

Among the three examined tetracyclines, MABC exhibited extremely high resistance rates to DOX and MIN, thereby limiting their use in treating MABC infections. Conversely, MABC showed an increased susceptibility rate to TGC, highlighting TGC administration as a viable treatment option for patients with MABC infections.

Isoegomaketone exhibits potential as a new Mycobacterium abscessus inhibitor

Although the incidence of Mycobacterium abscessus infection has recently increased significantly, treatment is difficult because this bacterium is resistant to most anti-tuberculosis drugs. In particular, M. abscessus is often resistant to available macrolide antibiotics, so therapeutic options are extremely limited. Hence, there is a pressing demand to create effective drugs or therapeutic regimens for M. abscessus infections. The aim of the investigation was to assess the capability of isoegomaketone (iEMK) as a therapeutic option for treating M. abscessus infections. We determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of iEMK for both reference and clinically isolated M. abscessus strains. In addition to time-kill and biofilm formation assays, we evaluated iEMK's capability to inhibit M. abscessus growth in macrophages using an intracellular colony counting assay. iEMK inhibited the growth of reference and clinically isolated M. abscessus strains in macrophages and demonstrated effectiveness at lower concentrations against macrophage-infected M. abscessus than when used to treat the bacteria directly. Importantly, iEMK also exhibited anti-biofilm properties and the potential to mitigate macrolide-inducible resistance, underscoring its promise as a standalone or adjunctive therapeutic agent. Overall, our results suggest that further development of iEMK as a clinical drug candidate is promising for inhibiting M. abscessus growth, especially considering its dual action against both planktonic bacteria and biofilms.

[A pharmacologic approach to treatment of Mycobacterium abscessus pulmonary disease]

Mycobacterium abscessus is a fast-growing non-tuberculous mycobacteria complex causing pulmonary infections, comprising the subspecies abscessus, massiliense and bolletii. Differences are based predominantly on natural inducible macrolide resistance, active in most Mycobacterium abscessus spp abscessus species and in Mycobacterium abscessus spp bolletii but inactive in Mycobacterium abscessus spp massiliense. Therapy consists in long-term treatment, combining multiple antibiotics. Prognosis is poor, as only 40% of patients experience cure. Pharmacodynamic and pharmacokinetic data on M. abscessus have recently been published, showing that therapy ineffectiveness might be explained by intrinsic bacterial resistance (macrolides…) and by the unfavorable pharmacokinetics of the recommended antibiotics. Other molecules and inhaled antibiotics are promising.

Effectiveness and safety of regimens containing linezolid for treatment of Mycobacterium abscessus pulmonary Disease

OBJECTIVE

To evaluate the effectiveness and safety of linezolid-containing regimens for treatment of M. abscessus pulmonary disease.

METHODS

The records of 336 patients with M. abscessus pulmonary disease who were admitted to Shanghai Pulmonary Hospital from January 2018 to December 2020 were retrospectively analyzed. A total of 164 patients received a linezolid-containing regimen and 172 controls did not. The effectiveness, safety, antibiotic susceptibility profiles, outcomes, culture conversion, cavity closure, and adverse reactions were compared in these two groups.

RESULTS

The two groups had similar treatment success (56.1% vs. 48.8%; P > 0.05), but treatment duration was shorter in the linezolid group (16.0 months [inter-quartile ranges, IQR: 15.0-17.0] vs. 18.0 months [IQR: 16.0-18.0]; P < 0.01). The rates of sputum culture conversion were similar (53.7% vs. 46.5%, P > 0.05), but time to conversion was shorter in the linezolid group (3.5 months [IQR: 2.5-4.4] vs. 5.5 months [IQR: 4.0-6.8]; P < 0.01). The linezolid group had a higher rate of cavity closure (55.2% vs. 28.6%, P < 0.05) and a shorter time to cavity closure (3.5 months [IQR: 2.5-4.4] vs. 5.5 months [IQR: 4.0-6.8]; P < 0.01). Anemia and peripheral neuropathy were more common in the linezolid group (17.7% vs. 1.7%, P < 0.01; 12.8% vs. 0.6%, P < 0.01).

CONCLUSIONS

The linezolid and control groups had similar treatment success rates. The linezolid group had a shorter treatment duration, shorter time to sputum culture conversion, and higher rate and shorter time to lung cavity closure. More patients receiving linezolid developed anemia and peripheral neuropathy.

Minimum Inhibitory Concentrations before and after Antibacterial Treatment in Patients with Mycobacterium abscessus Pulmonary Disease

The clinical importance of Mycobacterium abscessus (MABS) pulmonary disease has been increasing. However, there is still a lack of information about MIC distribution patterns and changes in clinical practice settings. The MIC results of rapidly growing mycobacteria isolated from 92 patients with nontuberculous mycobacterial pulmonary disease diagnosed from May 2019 to March 2021 were retrospectively analyzed. Most of the patients (86 patients; 93.5%) were infected with MABS; 46 with Mycobacterium abscessus subsp. abscessus (Mab), and 40 with Mycobacterium abscessus subsp. massiliense (Mma). Significant differences in susceptibility to clarithromycin (15.2% versus 80.0%, P < 0.001) and azithromycin (8.7% versus 62.5%, P < 0.001) were observed between Mab and Mma. Most isolates were susceptible to amikacin (80; 93.0%), and over half were susceptible to linezolid (48; 55.8%). Only one-quarter of isolates (22, 25.6%) were susceptible to imipenem, while more than half (56; 65.1%) had intermediate susceptibility. Fifty-one isolates (59.3%) had MIC values of less than 1 μg/mL for sitafloxacin, which were significantly higher than isolates for moxifloxacin (5; 5.8%), especially in Mab. Sixty-five (75.6%) isolates had MICs of less than 0.5 μg/mL to clofazimine. Two patients showed obvious MIC result changes: from susceptible to resistant to clarithromycin and from resistant to susceptible to amikacin and imipenem. In conclusion, MABS isolates were relatively susceptible to amikacin and linezolid, and clarithromycin and azithromycin were especially effective against Mma. In addition, sitafloxacin and clofazimine had low MICs and might be effective treatment agents. IMPORTANCE The MICs of isolates from 86 patients with Mycobacterium abscessus (MABS); 46 with Mycobacterium abscessus subsp. abscessus (Mab), and 40 with Mycobacterium abscessus subsp. massiliense (Mma) were retrospectively analyzed. The main findings are as follows: (i) Mma were significantly more susceptible to clarithromycin and azithromycin than Mab, and both subspecies tended to be more susceptible to clarithromycin than azithromycin. (ii) Most isolates were susceptible to amikacin (93.0%), and over half to linezolid (55.8%). (iii) Fifty-one isolates (59.3%) had MIC values of less than 1 μg/mL for sitafloxacin, and 65 (75.6%) had less than 0.5 μg/mL for clofazimine, which seems worth clinical investigating. (iv) Among nine cases analyzed chronological changes, only two patients showed obvious MIC result changes even after the long-term multidrug treatment. The present study revealed MICs of MABS clinical isolates before and after treatment in clinical settings, which could help develop future MABS treatments strategies.

Efficacy estimation of a combination of triple antimicrobial agents against clinical isolates of Mycobacterium abscessus subsp. abscessus in vitro

Background

Mycobacterium abscessus subsp. abscessus (M. abscessus) is a rapidly growing mycobacterium that is resistant to most antibiotics. The number of patients with pulmonary disease caused by M. abscessus is increasing in several regions, and therapy involves long-term antibiotic combination treatments, although no standard treatment regimen has been established.

Objectives

To examine candidate regimens for maintenance of antimicrobial treatment against M. abscessus by measuring MIC using the three-drug chequerboard method.

Methods

We evaluated the drug susceptibility of 70 clinical isolates of M. abscessus using the three-drug chequerboard method. We tested the antimycobacterial agents bedaquiline, clofazimine, amikacin, and sitafloxacin (which showed a relatively low MIC range when used as single agents) alone and in combinations.

Results

The three-drug combinations of bedaquiline/clofazimine/amikacin, and bedaquiline/clofazimine/sitafloxacin were studied. Among isolates for which the fractional inhibitory concentration index (FICI) could be calculated, 29/70 isolates (41%) and 11/70 isolates (16%) showed a synergistic response (FICI ≤0.75) with combined use of bedaquiline/clofazimine/amikacin, or with bedaquiline/clofazimine/sitafloxacin, respectively.

Conclusions

The combination of bedaquiline with clofazimine plus either amikacin or sitafloxacin may be useful as maintenance regimens when treating pulmonary disease caused by M. abscessus.