PHARYNGEAL CARRIAGE OF NEISSERIA MENINGITIDIS AMONG UNDERGRADUATE STUDENTS OF AHMADU BELLO UNIVERSITY, ZARIA

Abstract

Background: Neisseria meningitidis is an important cause of meningitis, and a major public
health problem in the African meningitis belt. University students are known to be at an
increased risk of invasive meningococcal disease because of factors such as overcrowding.
The study of meningococcal carriage is essential to understanding of the epidemiology of
Neisseria meningitidis. The study was aimed at assessing the prevalence of pharyngeal
carriage of N. meningitidis among university students of Ahmadu Bello University, Zaria; as
well as to identify serogroups, determine Minimum Inhibitory Concentrations (MICs), and
assess known factors associated with risk of carriage.
Methods: A descriptive cross sectional study was conducted in June 2014 among 336
undergraduate university students, who were randomly selected using a multistage sampling
technique. Pharyngeal swabs specimens were collected, and questionnaires were
administered to each participant; to obtain social demographic data and information on
factors associated with risk of carriage. Neisseria meningitidis was identified using standard
microbiological techniques.
Results: A total of 17 of 336 participants (5.1%; 95% Confidence Interval [CI] , 2.7% – 7.5%)
were pharyngeal carriers of meningococci. Carriage was more frequent in males, relative to
females (OR, 4.76; 95% CI, 1.03-20.39, p value – 0.03). Among the 17 isolates recovered,
serogroup Y predominated (29%), followed by serogroup A (18%), C (18%), and W
135(6%). Five isolates (29%) were non-groupable. Using Minimum Inhibitory
Concentrations (MICs), all N. meningitidis isolates were found to be susceptible to
ceftriaxone and rifampicin. Sixteen isolates (94%) were susceptible to ciprofloxacin, with 1
isolate (6%) having intermediate susceptibility to ciprofloxacin.
Conclusion: The prevalence of meningococcal carriage is low amongst university students
of Ahmadu Bello University, Zaria; with carriage being significantly higher in males.
Commonly used chemoprophylactic antibiotics demonstrated significant activity against the
meningococcal isolates. The high frequency of Serogroup Y suggests that there is a need to
strengthen surveillance and laboratory diagnosis of Neisseria meningitidis in Nigeria.

PHARYNGEAL CARRIAGE OF NEISSERIA MENINGITIDIS AMONG UNDERGRADUATE STUDENTS OF AHMADU BELLO UNIVERSITY, ZARIA