Molecular epidemiological investigation to determine the source of a fatal case of serotype 22F pneumococcal meningitis

Abstract

A child's death due to pneumococcal meningitis after contracting the disease in an after-school programme prompted an investigation to assess nasopharyngeal (NP) carriage among her contacts. The serotype of the meningitis case isolate was determined, together with the serotypes of the NP specimens of contacts, comprising the case patient's brother, the case patient's afterschool programme contacts and the brother's day-care centre (DCC) contacts. NP swabs from 155 children and 69 adults were obtained. Real-time PCR and conventional multiplex PCR (CM-PCR) assays were used to detect pneumococcal carriage and determine serotypes. Brothenriched culture of NP specimens followed by pneumococcal isolation and Quellung-based serotyping were also performed. DNA extracts prepared from cerebrospinal fluid of the index case and from the NP strain isolated from the brother and from one attendee of the brother's DCC were subjected to genotyping. Pneumococcal carriage assessed by real-time PCR and culture was 49.6 and 36.6 %, respectively (P,0.05). Twenty-three serotypes were detected using CM-PCR, with serotypes 6A/6B, 14, 19F, 6C/6D, 22F/22A, 23F and 11A/11D being the most frequent. All eight serotype 22F/22A NP specimens recovered were from children attending the brother's DCC. The meningitis case isolate and the NP carriage isolate from the patient's brother were both serotype 22F and shared the same new multilocus sequence type (ST6403) with the attendee of the brother's DCC. CM-PCR proved to be useful for assessing carriage serotype distribution in a setting of high-risk pneumococcal transmission. The causal serotype appeared to be linked to the brother of the case patient and attendees of his DCC.

Multiplex PCR to Streptococcus pneumoniae serotype identification directly in cerebrospinal fluid samples

“…Also, the mPCR can be helpful in the epidemiological evaluation of circulating serotypes and, consequently, in making accurate decisions about vaccination. This approach can also be useful in population-based studies where there is limited laboratory capability for taking on the highly demanding work of conventional pneumococcal isolation and serotyping [ 8 ].…”

Sorotipos e perfil de resistência antimicrobiana do <i>Streptococcus pneumoniae</i>: implicações clínicas na doença invasiva e no programa nacional de imunização (1998-2013)

“…No Brasil, a prevalência de portadores de pneumococo varia de 13% a 72%, dependendo da idade e presença de doenças associadas (FRANCO et al, 2010;LAMARO-CARDOSO et al, 2012). A colonização da mucosa é a primeira fase para o desenvolvimento da doença (Figura 5).…”