Nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus in a Brazilian elderly cohort

Abstract

We aimed to investigate the nasopharyngeal colonization (NPC) by Streptococcus pneumoniae , Haemophilus influenzae , and Staphylococcus aureus in the elderly population and to assess the demographic factors associated with NPC. This was an observational cohort study in which outpatients aged ≥60 years were enrolled from April to August 2017, with a follow-up visit from September through December 2017. Nasopharyngeal (NP) swabs were collected, bacteria were detected and isolated, and isolates were subjected to phenotypic and molecular characterization using standard microbiological techniques. At enrolment, the rates of S . aureus , methicillin-resistant S . aureus (MRSA), H . influenzae , and S . pneumoniae among 776 elderly outpatients were 15.9%, 2.3%, 2.5%, and 2.2%, respectively. Toxin production was detected in 21.1% of methicillin-susceptible S . aureus , and three SCC mec types were identified: II/IIb, IVa, and VI. At the follow-up visit, all carriage rates were similar (p > 0.05) to the rates at enrolment. Most of S . pneumoniae serotypes were not included in pneumococcal conjugate vaccines (PCVs), except for 7F, 3, and 19A. All strains of H . influenzae were non-typeable. Previous use of antibiotics and 23-valent pneumococcal polysaccharide vaccination (p < 0.05) were risk factors for S . aureus and MRSA carriage; S . aureus colonization was also associated with chronic kidney disease (p = 0.021). S . pneumoniae carriage was associated with male gender (p = 0.032) and an absence of diabetes (p = 0.034), while not receiving an influenza vaccine (p = 0.049) and chronic obstructive pulmonary disease (p = 0.031) were risk factors for H . influenzae colonization. The frailty of study participants was not associated with colonization status. We found a higher S . aureus carriage rate compared with the S . pneumoniae - and H . influenzae -carriage rates in a well-attended population in a geriatric outpatient clinic. This is one of the few studies conducted in Brazil that can support future colonization studies among elderly individuals.

Oropharyngeal Carriage of hpl-Containing Haemophilus haemolyticus Predicts Lower Prevalence and Density of NTHi Colonisation in Healthy Adults

“…However, carriage rates as low as 3–15% have also been reported in Kenya and Nepal [ 30 , 31 , 32 ], highlighting geographical differences in NTHi carriage. Despite their predisposition to NTHi-associated infections [ 33 ], information surrounding carriage rates in elderly demographics is limited to studies in Germany (2012–2013) and Brazil (2017), reporting rates of 1.9–2.5% [ 1 , 34 ]. It is unclear whether the substantially higher NTHi carriage rates detected in elderly participants is representative of the local population or of sampling bias.…”

“…Oropharyngeal (OP) swabs were collected due to ease of collection and participant tolerance. Several studies have reported similar or improved qPCR detection of NTHi and Hh from OP swabs compared to nasopharyngeal swabs [ 1 , 27 , 38 , 40 ]. OP swabs were collected by two investigators by depressing the tongue and rolling the tip of a sterile cotton swab on the posterior wall of either side of the oropharynx for 2 seconds, avoiding contact with the surface of the mouth to minimise contamination with mouth flora.…”

“…Nontypeable Haemophilus influenzae (NTHi) is a major bacterial cause of opportunistic infections in the respiratory tract, most notably otitis media in infants and young children, community-acquired pneumonia in the elderly, and acute exacerbations in individuals with chronic obstructive pulmonary disease (COPD) [ 1 , 2 ]. Collectively, these infections and subsequent long-term health complications, such as hearing loss or decline in lung function, impart a significant global disease burden [ 3 , 4 ].…”

“…Collectively, these infections and subsequent long-term health complications, such as hearing loss or decline in lung function, impart a significant global disease burden [ 3 , 4 ]. Asymptomatic pharyngeal colonisation occurs in 20–30% of healthy adults and 20–80% of children under the age of 5 and is characterised by the simultaneous carriage of multiple strains and a rapid turnover rate of constituent genotypes [ 1 , 2 , 5 , 6 , 7 , 8 ]. Week to week turnover rates of NTHi genotypes as high as 62% have been reported from healthy children attending day care [ 9 ].…”

The History of Methicillin-Resistant Staphylococcus aureus in Brazil

“…In addition to the New York/Japan clone, the production of biofilms and PVL began to be seen in more unusual and less frequent clones, such as those carrying SCC mec types V and I [ 114 , 115 ]. These types of cassettes, as well as the SCC mec type VI, UK/EMRSA-3, Hungarian, and Iberian clones, were identified in the history of MRSA in Brazil at a low frequency [ 104 , 116 – 119 ].…”