Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae in children with acute bacterial meningitis in Mozambique: implications for a national immunization strategy

Abstract

BackgroundS. pneumoniae is the leading cause of acute bacterial meningitis (ABM) in children. Vaccination using the 10-valent conjugate vaccine (PCV-10) was recently introduced into the National Immunization Program in Mozambique, but data on serotype coverage of this vaccine formulation are scarce. In this study, we investigated the serotype distribution and antimicrobial resistance of isolates of S. pneumoniae causing ABM in children < 5 years at the two largest hospitals in Mozambique.MethodsBetween March 2013 and March 2014, a total of 352 cerebrospinal fluid (CSF) samples were collected from eligible children, of which 119 (33.8 %) were positive for S. pneumoniae. Of these, only 50 samples met the criteria for serotyping and were subsequently serotyped using sequential multiplex PCR (SM-PCR), but 15 samples were non-typable.ResultsThe most common serotypes of S. pneumoniae were 1 (18.2 %), 5 (15.2 %), 14 (12.1 %), 9 V (12.1 %), 23 F (9.1 %), 6A (9.1 %), 4 (9.1 %) and 6B (6.1 %). Serotypes 1, 5, 9 V, 6A and 12 were mostly prevalent in Northern Mozambique, while serotypes 23 F, 4, 6B, 3 and 15B were predominant in Southern. Serotype coverage of PCV-10 and PCV-13 vaccine formulations were 81.8 % and 93.9 %, respectively. Serotypes 1, 3, 4, 6B, 14, 23 F were resistant to penicillin and sensitive to ceftriaxone.ConclusionsOur findings shows that changing the current in use PCV-10 vaccine formulation to PCV-13 formulation might increase substantially the protection against invasive strains of S. pneumoniae as the PCV-10 vaccine formulation does not cover the serotypes 3 and 6A, which are prevalent in Mozambique.

Surveillance of impact of PCV-10 vaccine on pneumococcal meningitis in Mozambique, 2013 – 2015

“…These rates are lower than those reported in a recently published paper from Mozambique, which reported coverage rates of PCV10 and PCV13 of 81.8% and 93.9%, respectively [14]. The decline in the serotype coverage of PCVs may be related to serotype replacement phenomenon.…”

“…The study was divided into 2 periods: baseline period, which corresponded to the year in which PCV10 was introduced in Mozambique (2013), and the follow up period, which corresponded to the period post introduction of PCV10 (2014–2015). We used serotype-specific data from March 2013 to March 2014 as previously reported by Nhantumbo et al [ 14 ] as the baseline for the comparison with the period post introduction of PCV10, in order to assess the impact of PCV10 on the burden and serotype distribution of pneumococcus.…”

“…A confirmed case of pneumococcal meningitis (PM) was defined as the presence of S . pneumoniae identified either by culture or multiplex qPCR in cerebrospinal fluid (CSF) [ 13 , 14 ].…”

“…However, the 13-valent PCV (PCV13) vaccine formulation is now available, which provides added coverage for the following serotypes 3, 6A and 19A to PCV10 [ 9 , 11 , 12 ]. A recent publication by our group showed that PCV10 formulation in use in Mozambique cover 81.8% of circulating serotypes in the country [ 14 ]. However, the impact of PCV10 immunization in Mozambique on the burden of pneumococcal disease and on the serotype distribution since the introduction of this vaccine is not yet known.…”

Susceptibility of Streptococcus pneumoniae causing bacterial meningitis in children in Yaoundé (Cameroon): results of a surveillance site

“…Susceptibility rates for erythromycin, chloramphenicol and tetracycline were also found to be 76.5%, 64.7%, and 35.3%, respectively. 29 In this study, resistance to most other antibiotics was more frequent in the PNSSP isolates than in the susceptible isolates. Pneumococcal antibiotic resistance is even more worrisome in developing countries because PNSSP strains are often multiresistant and because alternative antibiotics (e.g., third-generation cephalosporins) are expensive.…”