Data of the NRZMHi for Haemophilus influenzae 2018
The tasks of the National Reference Laboratory for Meningococci and Haemophilus influenzae (NRZMHi) assigned by the Robert Koch Institute for the surveillance of invasive Haemophilus influenzae disease include serotyping of clinical isolates from blood or cerebrospinal fluid (CSF) and the detection of antibiotic resistance against β-lactam antibiotics.
In 2018, all in all 803 submissions were analyzed including bacterial isolates from 649 patients with invasive infections. The NRZMHi could confirm the diagnosis Haemophilus influenzae in 636 cases with invasive disease. In 609 cases, H. influenzae was isolated from blood, 25 from cerebrospinal fluid (CSF) only. We received H. influenzae both from blood and CSF from two patients.
Detection of H. influenzae from these materials must be notified according to the German Infection Protection Act (IfSG). In 2018, the statutory notification system registered 843 invasive H. influenzae infections. Since the NRZMHi transmits all laboratory results to the local health authorities in charge, the coverage of the laboratory surveillance can be estimated based on these data. Thus, a coverage of 75% can be assumed for 2018.
As in previous years, the majority of blood or CSF isolates were non-typeable H. influenzae (NTHi, 526 isolates, 82.7 %), followed by Hif as the most frequent capsular serotype (69 cases; 10.8%). Hib and Hie showed third highest frequency among the serotypes (18 cases each; 2.8 %). Of the rare serotypes, five Hia (0.8%), and no Hic or Hid were isolated. Among the analyzed cases, the age group most affected was > 40 years (564 cases; 88.7 % of all cases). In addition, a significant percentage of cases (38 cases; 6.0 %) was found in children aged <5 years.
The NRZMHi analyzed the frequency of ampicillin resistance using gradient agar diffusion tests. One hundred and thirty four isolates (21.1 %) were ampicillin resistant (MIC > 1 µg/ml), of which 78 (52.2 %) showed β‑lactamase production. The NRZMHi has tested all isolates for cefotaxime susceptibility. Resistance to cefotaxime was found in 9 isolates (1.4%).
2. Serotype distribution of H. influenzae isolates from blood or CSF in 2017
3. Age distribution of patients with H. influenzae detected in blood or CSF
4. Serotype distribution in Federal States
5. Serotype distribution according to site of isolation