Antibiotic Susceptibility and Genotyping of Mycobacterium avium Strains That Cause Pulmonary and Disseminated Infection

Abstract

subsp. mainly causes disseminated infection in immunocompromised hosts, such as individuals with human immunodeficiency virus (HIV) infection, and pulmonary infection in immunocompetent hosts. However, many aspects of the different types of subsp. infection remain unclear. We examined the antibiotic susceptibilities and genotypes of subsp. isolates from different hosts by performing drug susceptibility testing using eight antibiotics (clarithromycin, rifampin, ethambutol, streptomycin, kanamycin, amikacin, ethionamide, and levofloxacin) and variable-number tandem-repeat (VNTR) typing analysis for 46 isolates from the sputa of HIV-negative patients with pulmonary subsp. disease without previous antibiotic treatment and 30 isolates from the blood of HIV-positive patients with disseminated subsp. disease. Interestingly, isolates from pulmonary subsp. disease patients were more resistant to seven of the eight drugs, with the exception being rifampin, than isolates from HIV-positive patients. Moreover, VNTR typing analysis showed that the strains examined in this study were roughly classified into three clusters, and the genetic distance from reference strain 104 for isolates from pulmonary subsp. disease patients was statistically significantly different from that for isolates from HIV-positive patients ( = 0.0018), suggesting that subsp. strains that cause pulmonary and disseminated disease have genetically distinct features. Significant differences in susceptibility to seven of the eight drugs, with the exception being ethambutol, were noted among the three clusters. Collectively, these results suggest that an association between the type of subsp. infection, drug susceptibility, and the VNTR genotype and the properties of subsp. strains associated with the development of pulmonary disease are involved in higher levels of antibiotic resistance.

The recombination-cold region as an epidemiological marker of recombinogenic opportunistic pathogen Mycobacterium avium

“…Hosts and niches of sequenced isolates are shown in Additional file 1: Table S13. Uchiya et al [40] reported a significant difference in antibiotic susceptibility between EA1, EA2, and SC2 human isolates4. Uchiya et al [37] reported a difference in chromosome structure between TH135 (EA2) and Mah104 (SC2)5.…”

“…3. Uchiya et al [40] reported a significant difference in antibiotic susceptibility between EA1, EA2, and SC2 human isolates…”

“…The current MAC phenotype–lineage relationship is rather vague, perhaps because lineage-informative loci have been undetected until now and it has been difficult to set up experimental research to address this problem. Recently, Uchiya et al [40] demonstrated that clinical isolates belonging to East Asian lineages are more resistant to antibiotics than those of the SC2 lineage. The SC4 lineage is associated with animals, particularly lymphadenitis in the digestive tracts of pigs [27], while SC2 is common in adult pulmonary infection and child lymphadenitis in Europe [22].…”

Comprehensive subspecies identification of 175 nontuberculous mycobacteria species based on 7547 genomic profiles

“…This diversity of NTM subspecies represents a significant obstacle against successful treatment, and current therapies require prolonged treatment and often lead to insufficient clinical outcomes due to the lack of subspecies identification [16]. Therefore, identifying NTM at a subspecies level is an essential step prior to treatment [14,15].…”

Genome Subtraction and Comparison for the Identification of Novel Drug Targets against Mycobacterium avium subsp. hominissuis

“…MAC pulmonary diseases are controlled by treatment with antibiotics that include macrolide-based multidrug therapy, comprising macrolides (clarithromycin or azithromycin) in combination with rifampin, ethambutol, aminoglycosides (streptomycin or amikacin) and ciprofloxacin [10,11]. However, emerging virulent strains are found to be resistant to these antibiotics [12].…”