Antimicrobial Resistance Genotype Trend and Its Association with Host Clinical Characteristics in Respiratory Isolates of <b><i>Haemophilus influenzae</i></b>

Abstract

Background: β-Lactam resistance genotype trends in clinical isolates of Haemophilus influenzae and their correlation with the clinical background were analyzed. Methods: Five hundred and ten respiratory isolates of H. influenzae collected during the period 2002–2009 were classified by PCR into gBLNAS (genotype for β-lactamase-negative ampicillin-susceptible), gBLNAR (genotype for β-lactamase-negative ampicillin-resistant) and 3 other genotypes. The associations with host clinical data and antimicrobial susceptibility were analyzed in all 144 isolates between 2008 and 2009. Results: The 8-year trend analysis detected an increase in gBLNAR with a decrease in gBLNAS. The probability of being a causative pathogen did not differ between genotypes. Host clinical characteristics such as age and gender did not differ with gBLNAR or gBLNAS, but the underlying respiratory diseases did differ. gBLNAR was found at the highest rate in 83% of isolates from patients with nontuberculous mycobacteriosis. In contrast, gBLNAR accounted for as little as 33% of isolates from chronic obstructive pulmonary disease. Conclusions: There were no differences in the pathogenicity of gBLNAR and gBLNAS. The underlying respiratory diseases may be related to the resistance genotype.

Ten-Year Trends and Clinical Relevance of the Antimicrobial Resistance Genotype in Respiratory Isolates of <b><i>Streptococcus pneumoniae</i></b>

“…Underlying respiratory diseases did not affect the genotype either in this study. In our previous study on clinical isolates of Haemophilus influenzae from adult patients, we showed that resistance genotype was more likely to be isolated in patients with bronchiectasis and nontuberculous mycobacteriosis among all other respiratory diseases [13]. This finding was not compatible with the present study.…”

“…Especially, our previous study on H. influenzae where β-lactam antibiotic resistance is also induced by PBP3 mutations focused on drug-resistance genotypes [13] and the results were well in agreement with those of the present study.…”

“…These results are consistent with the results of previous studies of other resistant strains such as MRSA [20] or H. influenzae [13] showing that drug resistance was not related to the severity of infection. Especially, our previous study on H. influenzae where β-lactam antibiotic resistance is also induced by PBP3 mutations focused on drug-resistance genotypes [13] and the results were well in agreement with those of the present study.…”

“…Clinical data including age, gender, underlying respiratory diseases, and laboratory data were obtained through a retrospective review of the medical records. The decision criteria applied to respiratory infections caused by the strains were: (1) the respiratory infection had clinical manifestations including purulent or increased sputum, cough, or fever, which were accompanied by elevated white blood cell counts and/or elevated levels of C-reactive protein or procalcitonin, and (2) the strain was isolated in significant amounts from good-quality sputum and no other organisms were possible candidate pathogens [13]. Approval from the institutional review board was obtained (approval No.…”

Multilocus sequence typing and ftsI sequencing: a powerful tool for surveillance of penicillin-binding protein 3-mediated beta-lactam resistance in nontypeable Haemophilus influenzae

“…Isolates with high-level resistance (high-rPBP3) are a major clinical problem in Japan and South Korea [15-17] whereas low-level resistant (low-rPBP3) isolates so far predominate in the rest of the world [4,11,12,14,18-21]. Group II isolates with a characteristic substitution pattern, PBP3 type A (D350N, M377I, A502V, N526K, V547I and N569S) [11], and compatible patterns (identical to PBP3 type A as far as comparison is possible) are particularly common [3,4,9,11,12,16,18,20],[22-25].…”