Bachiller Luque P, Eiros Bouza J M, Blanco Quirós A
Hospital Universitario del Río Hortega, Facultad de Medicina, Departamento de Microbiología, Valladolid.
An Med Interna. 2000 Apr;17(4):204-12.
Haemophilus influenzae is a small, nonmotile, non-spore-forming bacterium, and a strict parasite of humans found principally in the upper respiratory tract. The production of capsule is of major significance to clinicians since it is an important virulence factor. We described six antigenically distinct capsular types, designated a-f. Spread from one individual to another occurs by airborne droplets or by direct contagion with secretions. Haemophilus influenzae produces at least two factors that inhibit the ciliary activity of human epithelial cells in vitro. One of this has been shown to be lipopolysaccharide and the other factor is of low molecular weight, most likely a heat-stable glycopeptide. Type b strains are distinguished by the production of capsular polysaccharide composed of repeating units of ribosyl-ribitol phosphate, account for greater than 95 percent of systemic infections in children. Two contrasting patterns of Haemophilus influenzae disease can be identified. The first and the most serious in its consequences is invasive infection such as meningitis, septic arthritis, epiglottitis, and cellulitis in which bacteremia is a prominent feature; these infections are usually caused by type b strains and occur in young children. The second category includes less serious but numerically more common infections, that occur as a result of contiguous spread of Haemophilus influenzae within the respiratory tract; e.g. otitis media, sinusitis. These latter infections are usually, but not invariably, caused by unencapsulated strains. A provisional diagnosis of meningitis, epiglottitis, facial cellulitis, or septic arthritis will usually be prompted by the history and clinical findings. Confirmation requires microbiologic studies. Cultures of blood, CSF and other normally sterile fluids are diagnostic and therefore under the appropriate circumstances mandatory. Whenever feasible, specimens obtained for culture should also the gram-strained. Detection of capsular antigen in serum, CSF or concentrated urine using immunoelectrophoresis, latex agglutination or enzyme linked immunosorbent assay may be diagnosed and can be found in up to 90 percent of culture proved cases of meningitis. Without treatment, infection due to Haemophilus influenzae can be rapidly fatal, particularly by meningitis and epiglottitis. There is currently a trend to use certain parenteral third generation cephalosporins as initial therapy when lifethreatening Haemophilus influenzae infection is known or suspected in children beyond the neonatal period, commonly used agents included cefotaxime or ceftriaxone. Antibiotic therapy is only one facet of the management of the child with Haemophilus influenzae infection, and critical attention must also be given to supportive therapy. In the ambulatory setting, ampicillin or amoxicillin for 10 days is often satisfactory for the less severe Haemophilus influenzae infections. Cephalosporins are often chosen for treatment of adults, with pneumonia when Haemophilus influenzae is documented.
流感嗜血杆菌是一种小型、无运动性、不形成芽孢的细菌，是主要寄生于人类上呼吸道的严格寄生菌。荚膜的产生对临床医生具有重要意义，因为它是一种重要的毒力因子。我们描述了六种抗原性不同的荚膜类型，命名为a - f。它通过空气飞沫或与分泌物直接接触在个体之间传播。流感嗜血杆菌在体外至少产生两种抑制人类上皮细胞纤毛活动的因子。其中一种已被证明是脂多糖，另一种因子分子量低，很可能是一种热稳定糖肽。b型菌株的特征是产生由核糖醇磷酸重复单元组成的荚膜多糖，占儿童全身感染的95%以上。流感嗜血杆菌疾病可分为两种截然不同的类型。第一种也是后果最严重的是侵袭性感染，如脑膜炎、化脓性关节炎、会厌炎和蜂窝织炎，其中菌血症是一个突出特征；这些感染通常由b型菌株引起，发生在幼儿身上。第二类包括不太严重但在数量上更常见的感染，是由流感嗜血杆菌在呼吸道内的连续传播引起的；例如中耳炎、鼻窦炎。这些后期感染通常（但并非总是）由无荚膜菌株引起。脑膜炎、会厌炎、面部蜂窝织炎或化脓性关节炎的初步诊断通常由病史和临床发现提示。确诊需要微生物学研究。血液、脑脊液和其他通常无菌的体液培养具有诊断价值，因此在适当情况下是必需的。只要可行，用于培养的标本也应进行革兰氏染色。使用免疫电泳、乳胶凝集或酶联免疫吸附测定法检测血清、脑脊液或浓缩尿中的荚膜抗原可用于诊断，在高达90%的经培养证实的脑膜炎病例中可检测到。未经治疗，流感嗜血杆菌感染可能迅速致命，尤其是脑膜炎和会厌炎。目前有一种趋势，当已知或怀疑新生儿期后的儿童患有危及生命的流感嗜血杆菌感染时，使用某些肠外第三代头孢菌素作为初始治疗，常用药物包括头孢噻肟或头孢曲松。抗生素治疗只是流感嗜血杆菌感染患儿治疗的一个方面，还必须高度重视支持治疗。在门诊环境中，对于不太严重的流感嗜血杆菌感染，使用氨苄西林或阿莫西林治疗10天通常就足够了。当记录到流感嗜血杆菌引起肺炎时，头孢菌素通常被选用于成人治疗。
