Antibacterial Resistance in Lower Respiratory Tract Bacterial Pathogens: A Multicenter Analysis from Turkey

Abstract

Introduction: This study aimed to evaluate the etiology of lower respiratory tract infections (LRTIs) and their antibiotic resistance. Methodology: Bacterial culture results of LRT samples from 17 hospitals between 2016-2019 were included in the study. All isolates were identified and AST were performed by automated microbiology systems. AST was performed according to EUCAST. Results: Non-duplicate 30,051 (26,890 HA and 3156 CA) isolates detected as causative pathogen. LRTIs are caused by 85.1% Gram-negative bacterial pathogens and 14.9% Gram-positive. The most common isolates among HA pathogens were Acinetobacter spp. (27.4%), P.aeruginosa (22.2%), K.pneumoniae (17.9%); among CA pathogen S.pneumoniae (19.9%), P. aeruginosa (18.9%), H.influenzae (14.6%). ESBL rate was 62.5% in K.penumoniae; 53.1% in E.coli; 19.1% in Klebsiella spp; 13.9% in Enterobacter spp.; 8.6% in Proteus spp.; 6.3% in Citrobacter spp.; and 4.3% in Serratia spp. Resistance rates to carbapenems and colistin were 92.8% and 12.8% in A baumannii, 39.8% and 7.5% in P.aeruginosa, 47.3% and 18.5% in K.penumoniae. Among staphylococci, 27.3% of S. aureus and 82.4% of CoNS were methicillin resistant. 7.6% of E.faecium and 0.9% of E.faecalis were vancomycin resistant.  Linezolid resistant S. aureus, CoNS, E.faecalis and E.faecium rates were 0.3%, 2.9%, 0.0% and 4.6%. Inducible clindamycin resistant rate was 17.2% in S. aureus 38.2% in CoNS. Non-susceptible S.pneumoniae isolate rate to penicillin was 37.0%. 6.5% of S.maltophilia and 4.4% of B.cepacia isolates were resistant to trimethoprim/sulfamethoxazole. Conclusions: Antibiotic resistance was mainly observed among A.baumannii and K.pneumoniae and continuous surveillance of antimicrobial resistance patterns in the management of LRTIs is important.