Efficacy of Moxifloxacin against Mycobacterium abscessus in Zebrafish Model in vivo

Objective Moxifloxacin(MFX)shows good in vitro activity against Mycobacterium abscessus and can be a possible antibiotic therapy to treat M.abscessus infection;however,other studies have shown a lower or no activity.We aimed to evaluate MFX activity against M.abscessus using zebrafish(ZF)model in vivo.Methods A formulation of M.abscessus labeled with CM-Dil was micro-injected into ZF.Survival curves were determined by recording dead ZF every day.ZF were lysed,and colony-forming units(CFUs)were enumerated.Bacteria dissemination and fluorescence intensity in ZF were analyzed.Inhibition rates of MFX and azithromycin(AZM,positive control)were determined and compared.Results Significantly increased survival rate was observed with different AZM concentrations.However,increasing MFX concentration did not result in a significant decrease in ZF survival curve.No significant differences in bacterial burdens by CFU loads were observed between AZM and MFX groups at various concentrations.Bacterial fluorescence intensity in ZF was significantly correlated with AZM concentration.However,with increasing MFX concentration,fluorescence intensity decreased slightly when observed under fluorescence microscope.Transferring rates at various concentrations were comparable between the MFX and AZM groups,with no significant difference.Conclusion MFX showed limited efficacy against M.abscessus in vivo using ZF model.Its activity in vivo needs to be confirmed.

Prevalence and Antimicrobial Susceptibility of Mycobacterium abscessus in a General Hospital, China

Objective To gain greater insight into the prevalence drug resistant profiles of M. abscessus from a general hospital in Beijing, China. Methods Partial gene sequencing of 16 S, hsp65, and rpo B were used to distinguish the species of NTM isolates. All strains identified as M. abscessus were further enrolled in the drug susceptibility testing by using broth microdilution method. Results We found that M. avium complex was the most frequent NTM organism, accounting for 54.1%（33/61） of all isolates. Behind MAC, the second most common organisms were M. abscessus（22 out of 61, 36.1%）. Average rates of resistance were 4.5% for AMK, 9.1% for LZD, and 13.6% for CLA, respectively. In contrast, resistance to LEV（17/22, 77.3%）, IMI（9/22, 40.9%）, and SMX（10/22, 45.5%） was noted in more than 40% of M. abscessus isolates. DNA sequencing revealed that all the CLA-resistant isolates harbored nucleotide substitutions in position 2058（1/3, 33.3%） or 2059（2/3, 66.7%） of 23 S r RNA. Conclusion In conclusion, our data demonstrated that M. intracellulare and M. abscessus were the most common NTM species in the general hospital of Beijing. CLA, AMK, LZD showed promising activity, where as LEV, IMI, and SMX exhibited poor activity against M. abscessus in vitro.

Mycobacterium abscessus infection after facial injection of argireline:A case report

BACKGROUND The incidence of infection with Mycobacterium abscessus(M.abscessus)has increased in recent years.This increase is partly associated with invasive cosmetic procedures.CASE SUMMARY The purpose of this case summary is to increase clinicians'awareness of M.abscessus infection and reduce mycobacterial infection caused by cosmetic procedures.We report the case of a 45-year-old woman who received acetyl hexapeptide-8(argireline)injections in the forehead and temples,and erythema,nodules,and abscesses appeared at the injection sites after one week.The pus specimens were examined by microbiological culture and confirmed to be positive for M.abscessus.Clarithromycin 500 mg twice daily and moxifloxacin 400 mg once daily were administered for 5 mo and the lesions gradually subsided.CONCLUSION We report here for the first time a case of infection with M.abscessus after argireline injection.This condition is easily misdiagnosed as a common bacterial infection.Microbiological examinations are helpful for diagnosis and standardized cosmetic procedures can prevent infection with M.abscessus.

Catheter-related infections caused by Mycobacterium abscessus in a patient with motor neurone disease:A case report

BACKGROUND Mycobacterium abscessus(M.abscessus)is a rapidly growing mycobacterium and ubiquitous in the environment,which infrequently causes disease in humans.However,it can cause cutaneous or respiratory infections among immunocompromised hosts.Due to the resistance to most antibiotics,the pathogen is formidable and difficult-to-treat.CASE SUMMARY Here,we present a case of catheter-related M.abscessus infections in a patient with motor neurone disease.Catheter and peripheral blood cultures of the patient showed positive results during Gram staining and acid-fast staining.The alarm time of catheter blood culture was 10.6 h earlier than that of peripheral blood.After removal of the peripherally inserted central catheter,secretion and catheter blood culture were positive.M.abscessus was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry and 16S rDNA sequencing.CONCLUSION For catheter-related M.abscessus infection,rapid diagnosis and timely and adequate antimicrobial therapy are crucial.

Drug Repurposing for the Treatment of Mycobacterium abscessus Infections

With the ever-increasing burden of antimicrobial resistance,the demand to introduce countermeasures becomes increasingly critical.The urgency of this need is intensified by the void in antibiotic discovery,with the identification of novel compounds declining with time.Of increasing concern is Mycobacterium abscessus,which displays high levels of intrinsic resistance that lead to poor success rates,even after lengthy drug regimens.Research tackling these issues is now focused on the repurposing of preexisting drugs for antimycobacterial use,facilitating the discovery of antimicrobial compounds amidst a crisis where novel antibiotics are sparse.Part of this includes the use of combination treatments,whereby coadministration of synergistic compounds can reduce dose requirements and slow the progression of antimicrobial resistance in the long term.In this review,we will introduce the current therapeutic options for M.abscessus and provide insight into why treatment is so burdensome.We will also compile the current updates within drug repurposing for this pathogen,including the use of unconventional agents such as antimalarial drugs,the repositioning of antitubercu-losis candidates and the repurposing of preexisting antibiotics,including the application of combination regimens.In addition,the in vitro drug screening platforms used in their discovery will be appraised,with the view of highlighting potential future perspectives that may help increase physiological relevance.This review provides a timely appraisal of the future of M.abscessus treatment.

Clinical isolates of Mycobacterium abscessus in Guangzhou area most possibly from the environmental infection showed variable susceptibility

Background Mycobacterium abscessus （M. abscessus） can cause a variety of human infections, involving the lung, skin and soft tissues, and is generally believed to be acquired from environmental sources. The aim of this study was to investigate the molecular diversity and antibiotic susceptibility of M. abscessus isolates as the basis for strategies to improve control and management of infection. Methods Seventy M. abscessus isolates from patients attending the Guangzhou Thoracic Hospital were identified from 2003 to 2005 by biochemical tests, gas chromatography, polymerase chain reaction （PCR）-restriction analysis （PRA） of heat shock protein gene hsp65, and sequencing of the quinolone resistance determining regions （QRDRs） of gyrA. Susceptibilities to six antibiotics were determined by micro-broth dilution. Isolates were genotyped using randomly amplified polymorphic DNA （RAPD） analysis. Results Most isolates （63/70; 90%） were susceptible to amikacin but rates of susceptibility to other antibiotics varied from moderate, clarithromycin （60%） and imipenem （43%）, to low for ciprofloxacin and ofloxacin （3%）, and 87% of isolates had intermediate susceptibility to cefoxitin. RAPD analysis showed that the 70 clinical isolates displayed 69 unique RAPD patterns. Conclusions The high genetic diversity of isolates suggests that they are not transmitted from person to person but, presumably, are acquired independently from environmental sources. M. abscessus isolates displayed variable levels of susceptibility to all antibiotics tested, other than amikacin, indicating a need for routine susceptibility testing to guide treatment.

Novel Species Including Mycobacterium fukienense sp. Is Found from Tuberculosis Patients in Fujian Province, China, Using Phylogenetic Analysis of Mycobacterium chelonae/abscessus Complex

Objective To identify the novel species ‘Mycobacterium fukienense＇ sp. nov of Mycobacterium chelonoe/abscessus complex from tuberculosis patients in Fujian Province, China. Methods Five of 27 clinical Mycobucterium isolates （CIs） were previously identified as M. chelonoe/obscessus complex by sequencing the hsp65, rpoB, 165-235 rRNA internal transcribed spacer region （its）, recA and sodA house-keeping genes commonly used to describe the molecular characteristics of Mycobocterium. Clinical Mycobecterium isolates were classified according to the gene sequence using a clustering analysis program. Sequence similarity within clusters and diversity between clusters were analyzed. Results The 5 isolates were identified with distinct sequences exhibiting 99.8% homology in the hsp65 gene. However, a complete lack of homology was observed among the sequences of the rpoB, 165-235 rRNA internal tronscribed spacer region （its）, sodA, and recA genes as compared with the M. obscessus. Furthermore, no match for rpoB, sodA, and recA genes was identified among the published sequences. Conclusion The novel species, Mycobacterium fukienense, is identified from tuberculosis patients in Fujian Province, China, which does not belong to any existing subspecies of M. cheloneo/abscessus complex.

Comparison of Susceptibilities of M. tuberculosis H37Ra and M. chelonei subsp. Abscessus to Disinfectants

Objective To determine the susceptibilities of M. tuberculosis H37Ra and M. chelonei subsp. absecessus to several frequently-used disinfectants and to evaluate the practicability of surrogating M. tuberculosis by the latter. Methods A suspension quantitative bactericidal test was set up in accordance with Chinese Technique Standard for Disinfection to evaluate the susceptibility of each mycobacteria strain to each selected disinfectant. Killing log value was used as criterion in comparing the susceptibility to disinfectants between the two strains. Results M. chelonei subsp. abscessus was more resistant to chlorine disinfectant than M. tuberculosis while the two strains were similarly resistant to iodophor disinfectant, peracetic acid, alcohol and glutaraldehyde disinfectant. Conclusion M. chelonei subsp. abscessus has the potential to surrogate M. tuberculosis in evaluating mycobactericidal efficacies of disinfectants.

Molecular Epidemiology of Nontuberculous Mycobacteria in a German CF Center and Clinical Course of NTM Positive Patients

Goal of this study was to analyse the clinical course of cystic fibrosis (CF) patients with nontuberculous mycobacteria (NTM) in their respiratory secretions and to investigate the molecular epidemiology of the most prevalent NTM species by multilocus sequence analysis (MLSA). The respiratory specimen and the clinical parameters forced expiratory volume in one second (FEV1), body-mass-index (BMI), erythrocyte sedimentation rate (ESR) 1 h and immunoglobulin G (IgG) of 357 CF patients, 0 - 52.4 years, mean FEV1 2009 81.5% pred were analysed between 1998 and 2010. In 13 patients NTM were detected. 12 of 13 patients carried M. abscessus, for one patient the NTM species was not characterized. 4 patients carried a second NTM species (M. avium, M. chelonae (2x), M. intracellulare). 6 patients exhibited a significant decline in FEV1, however changes in BMI, IgG and ESR were discordant. Molecular genotyping of M. abscessus isolates revealed a unique MLSA pattern in 6 patients. 2 patients harboured identical strains, and one patient a closely related strain. Whether the presence of identical strains is attributed to the acquisition of NTM clones from common environmental sources or to patient-to-patient transmission cannot be definitely clarified. Although cross-in- fection of the three patients with identical/closely related strains in the present cohort is highly unlikely, we recommend strict hygiene measures for all CF patients harbouring NTM.