ABSTRACT
@#Abstract: Objective To identify the species of Mycobacteroides abscessus complex (MABC) in patients with pulmonary infection from the Second Affiliated Hospital of Hainan Medical University, and to investigate the species types, drug sensitivity and population distribution of MABC in pulmonary infection in Hainan. Methods Respiratory tract specimens were collected from suspected tuberculosis patients who visited the Second Affiliated Hospital of Hainan Medical University from January 2014 to December 2021 and cultured for Mycobacterium isolation. Non-tuberculous mycobacteria (NTM) strains were preliminarily identified by p-nitrobenzoic acid/thiophen-2-carbohydrazide (PNB/TCH) medium and DNA microarray chip, and then MABC and its subspecies were identified by hsp65 and rpoB gene sequencing. In vitro antimicrobial susceptibility test was performed by broth microdilution method. Results A total of 3 025 respiratory specimens from suspected pulmonary tuberculosis patients were collected during the study period. Among the 123 patients with identified MABC isolates, 124 MABC strains were isolated and identified, including 74 strains of Mycobacteroides abscessus subsp. abscessus, 38 strains of Mycobacteroides abscessus subsp. massiliense and 12 strains of Mycobacteroides abscessus subsp. bolletii. Among them, 118 patients had single MABC subspecies infection, one patient had mixed infection with two MABC subspecies, two patients had mixed infection with MABC and other NTM, and two cases had mixed infection with MABC and M.tuberculosis. There were more female patients than male patients with a ratio of 1:0.64, and those aged 50 and above amounted to 76.42% (94/123, 95%CI: 67.93%-83.61%). There was no significant difference in age distribution between male and female patients (Z=-0.944, P=0.347). The drug susceptibility results showed that all MABC strains were sensitive to Tigecycline (TGC), with a resistance rate of 0.81% (1/124) to Amikacin (AK), and resistance rates of 6.45% (8/124), 32.26% (40/124), and 74.19% (92/124) to Cefoxitin (FOX), Linezolid (LZD), and Imipenem (IPM), respectively. For Clarithromycin (CLR), MABC showed induced resistance , and there was a statistically significant difference in the CLR (14D) resistance rates among the three subspecies (χ2=66.335, P<0.001). The resistance rates to Tobramycin (TOB), Doxycycline (DOX), Moxifloxacin (MFX), Ciprofoxacin (CIP), Trimethoprim/Sulfamethoxazole (TMP-SMX), and Amoxicillin/Clavulanic acid (AMC) were high, all >80%. Conclusion In Hainan Province, pulmonary infections with MABC are mainly caused by Mycobacteroides abscessus subsp. Abscessus, which show high rates of inducible resistance to CLR. Timely and accurate identification of MABC to subspecies and drug susceptibility testing are of significant important for clinical decision-making.
ABSTRACT
@#Abstract： Objective To analyze the characteristics and corresponding drug resistance of pathogenic bacterial spectrum in eight major infection sites of hospitalized patients, and to provide epidemiological data for the rational selection of antibiotics in clinical practice. Methods A total of 396 bacterial strains isolated from clinical specimens of hospitalized patients in member institutions of the Hainan Provincial Bacterial Resistance Monitoring Network from September 1, 2020, to September 30, 2022, were included in this study. Data were screened and filtered from the database of MH120 Microbial Identification and Drug Sensitivity Analysis System based on the technical scheme of the National Bacterial Drug Resistance Surveillance Network and Science and Technology Basic Resources Investigation Project research plan in 2020. The testing data were integrated, summarized, and analyzed using EXCEL and WHONET 5.6 software, and statistical analysis was conducted using SPSS 26.0 software. Results Among of 396 strains of bacteria, 78 (19.7%) were isolated from respiratory tract specimens, 74 (18.7%) from urinary tract specimens, 72 (18.2%) from blood specimens, 54 (13.6%) from abdominal cavity specimens, 48 (12.1%) from skin and soft tissue specimens 48 strains (12.1%), 30 (7.6%) from reproductive tract specimens, 22 (5.6%) from central nervous system specimens, 18 (4.5%) from digestive tract specimens. Gram-negative bacteria accounted for 69.4% of the isolates, while gram-positive bacteria accounted for 30.6%. The top five gram-negative bacteria isolated were Klebsiella pneumoniae (14.9%), Escherichia coli (14.4%), Pseudomonas aeruginosa (10.4%), Acinetobacter baumannii (5.3%), and Salmonella species (4.5%). The top five gram-positive bacteria were Staphylococcus aureus (11.1%), Streptococcus agalactis (7.8%), Enterococcus faecalis (3.0%), Enterococcus faecium (2.8%), and Streptococcus suis (1.8%). Respiratory failure and bloodstream infection were independent influencing factors of treatment response (P<0.01). The resistance rate of Escherichia coli to ampicillin was 81.4%, and the resistance rate of Staphylococcus aureus to gentamicin and levofloxacin were both below 7%. Conclusions The pathogen spectra vary with different infection sites of patients, and rational selection of antibiotics based on drug susceptibility testing is crucial to shorten the treatment time of patients and avoid the unnecessary emergence of drug-resistant strains caused by drug abuse.