Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Preventiongrid.416738.f, Atlanta, Georgia, USA.
Weems Design Studio, Inc., Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Preventiongrid.416738.f, Atlanta, Georgia, USA.
Microbiol Spectr. 2022 Jun 29;10(3):e0257921. doi: 10.1128/spectrum.02579-21. Epub 2022 May 10.
Antibiotics are important for the treatment and prevention of invasive Haemophilus influenzae disease. Reduced susceptibility to clinically relevant drugs, except ampicillin, has been uncommon in the United States. Susceptibility of 700 invasive H. influenzae isolates, collected through population-based surveillance during 2016, was assessed for 15 antibiotics using broth microdilution, according to the CLSI guidelines; a subset of 104 isolates were also assessed for rifampin susceptibility using Etest. Genomes were sequenced to identify genes and mutations known to be associated with reduced susceptibility to clinically relevant drugs. A total of 508 (72.6%) had reduced susceptibility to at least one antibiotic and more than half of the isolates exhibited reduced susceptibility to only one (33.6%) or two (21.6%) antibiotic classes. All tested isolates were susceptible to rifampin, a chemoprophylaxis agent, and <1% ( = 3) of isolates had reduced susceptibility to third generation cephalosporins, which are recommended for invasive disease treatment. In contrast, ampicillin resistance was more common (28.1%) and predominantly associated with the detection of a β-lactamase gene; 26.2% of isolates in the collection contained either a TEM-1 or ROB-1 β-lactamase gene, including 88.8% of ampicillin-resistant isolates. β-lactamase negative ampicillin-resistant (BLNAR) isolates were less common and associated with mutations; resistance to amoxicillin-clavulanate was detected in <2% ( = 13) of isolates. The proportion of reduced susceptibility observed was higher among nontypeable H. influenzae and serotype e than other serotypes. US invasive H. influenzae isolates remain predominantly susceptible to clinically relevant antibiotics except ampicillin, and BLNAR isolates remain uncommon. Antibiotics play an important role for the treatment and prevention of invasive Haemophilus influenzae disease. Antimicrobial resistance survey of invasive H. influenzae isolates collected in 2016 showed that the US H. influenzae population remained susceptible to clinically relevant antibiotics, except for ampicillin. Detection of approximately a quarter ampicillin-resistant and β-lactamase containing strains demonstrates that resistance mechanisms can be acquired and sustained within the H. influenzae population, highlighting the continued importance of antimicrobial resistance surveillance for H. influenzae to monitor susceptibility trends and mechanisms of resistance.
抗生素对于治疗和预防侵袭性流感嗜血杆菌病非常重要。在美国，除了氨苄西林之外，对临床相关药物的敏感性降低并不常见。根据 CLSI 指南，使用肉汤微量稀释法对 2016 年通过基于人群的监测收集的 700 株侵袭性流感嗜血杆菌分离株的 15 种抗生素的敏感性进行了评估；其中 104 株分离株还使用 Etest 评估了利福平的敏感性。对基因组进行测序，以鉴定与临床相关药物敏感性降低相关的基因和突变。共有 508 株（72.6%）对至少一种抗生素的敏感性降低，超过一半的分离株仅对一种（33.6%）或两种（21.6%）抗生素类别表现出敏感性降低。所有测试的分离株均对利福平（一种化学预防剂）敏感，并且<1%（=3）的分离株对第三代头孢菌素的敏感性降低，这些抗生素被推荐用于侵袭性疾病的治疗。相比之下，氨苄西林耐药更为常见（28.1%），主要与β-内酰胺酶基因的检测有关；在该分离株集中，26.2%的分离株含有 TEM-1 或 ROB-1β-内酰胺酶基因，包括 88.8%的氨苄西林耐药分离株。β-内酰胺酶阴性氨苄西林耐药（BLNAR）分离株较少见，与突变有关；在<2%（=13）的分离株中检测到阿莫西林-克拉维酸耐药。在非典型流感嗜血杆菌和血清型 e 中观察到的敏感性降低比例高于其他血清型。美国侵袭性流感嗜血杆菌分离株对除氨苄西林以外的临床相关抗生素仍然主要敏感，BLNAR 分离株仍然少见。抗生素在治疗和预防侵袭性流感嗜血杆菌病方面发挥着重要作用。2016 年收集的侵袭性流感嗜血杆菌分离株的抗生素耐药性调查显示，美国流感嗜血杆菌人群对除氨苄西林以外的临床相关抗生素仍然敏感。约四分之一的氨苄西林耐药和含β-内酰胺酶的菌株的检测表明，耐药机制可以在流感嗜血杆菌人群中获得和维持，这突出表明，为监测流感嗜血杆菌的敏感性趋势和耐药机制，继续进行抗生素耐药性监测非常重要。
