Streptococcus pneumoniae colonization in health care professionals at a tertiary university pediatric hospital

Abstract

Streptococcus pneumoniae is a commensal of the human upper respiratory tract. In certain cases, it can lead to serious invasive infections peaking in very young children and the elderly. Especially young children are frequent carriers and are thus regarded as the reservoir for horizontal transmission of pneumococci. This is the first study evaluating pneumococcal colonization patterns in healthcare professionals working in a tertiary care pediatric hospital, including carriage prevalence, serotype distribution, and risk factors for carriage. One oropharyngeal and one nasal swab per individual were directly plated onto appropriate agar plates and conventional culture was used for bacterial identification. Pneumococcal isolates underwent serotyping using Neufeld’s Quellung reaction with type-specific antisera. Additional nasal and oropharyngeal swabs were taken for qPCR analysis targeting lytA. In total, 437 individuals were enrolled. S. pneumoniae was isolated in 4.8% (21/437) of the study cohort using conventional culture and in 20.1% (88/437) of subjects using qPCR. Independent risk factors for pneumococcal carriage were living in the same household with children under 8 years of age and being aged 36–45 years with a carriage prevalence reaching 11.6% (vs. 2.9%, p = 0.002) and 6.7% (vs. 4.3%, p = 0.029), respectively. The most common serotypes were 6C and 3. A total of 71.4% (15/21) of the detected serotypes are not included in any currently available pneumococcal vaccine; 28.6% (6/21) of the carried serotypes are included in the PCV13 vaccine. We found a relevant amount of pneumococcal carriage bearing the potential risk of horizontal in-hospital transmission.

Pneumococcal carriage among high-risk adults in a country with nonmandatory pneumococcal vaccination during the coronavirus disease 2019 pandemic

“…These carriage data are important for public health decision-making on vaccine licensure or post-vaccine introduction evaluation [21] . Our findings were consistent with previous studies conducted among unvaccinated high-risk adults prior to vaccine deployment, which found a prevalence of pneumococcal carriage ranging from 17.9% to 33.5% [8] , [28] , [29] . Compared to previous studies on Thais, we found that Serotypes 19 and 6 were the major serotypes for carriage and IPD [1] , [30] , [31] , but the other serotypes for carriage and IPD were inconsistent.…”

“…However, this study revealed that 45% of pneumococcal serotype carriages were non-vaccine type. Even though the pneumococcal vaccine uptake rate was low, most carriage serotypes were not covered by the vaccine [28] , [29] , so carriage data after pneumococcal licensure should be interpreted with caution. Nonetheless, surveillance on serotype distribution among IPD and carriage should be conducted at the individual level to determine the causal relationship between carriage and IPD.…”

High Levels of Detection of Nonpneumococcal Species of Streptococcus in Saliva from Adults in the United States

“…Updated World Health Organization (WHO) recommendations made in 2013 by the Pneumococcal Carriage Working Group advised the inclusion of oropharyngeal swabs from adults when possible ( 20 ). A number of studies have demonstrated that the sensitivity of carriage detection can be further improved when molecular methods are applied ( 21 – 26 ) and when alternative sample types such as saliva are used ( 4 , 12 , 27 ). With increased use of molecular methods, there have been increased reports of confounding by nonpneumococcal Streptococcus spp., leading to uncertainty regarding the accuracy of culture-independent approaches ( 10 , 13 , 14 , 22 , 28 ).…”

“…A number of studies have demonstrated that the sensitivity of carriage detection can be further improved when molecular methods are applied ( 21 – 26 ) and when alternative sample types such as saliva are used ( 4 , 12 , 27 ). With increased use of molecular methods, there have been increased reports of confounding by nonpneumococcal Streptococcus spp., leading to uncertainty regarding the accuracy of culture-independent approaches ( 10 , 13 , 14 , 22 , 28 ). When implementing previously established molecular methods ( 12 ) to standardize approaches for the detection of pneumococcus in saliva from healthy adults between geographic locales, we noted potential confounding with a large proportion of saliva samples (45 of 103 (44%) individuals sampled) testing PCR positive for lytA but negative for piaB .…”

Detection of pneumococcal carriage in asymptomatic healthcare workers

“…1 Prior studies have demonstrated that contact with children is associated with higher pneumococcal carriage prevalence in adults, 1,2 including healthcare workers working in the pediatric setting. 3 Since healthcare workers are often exposed to the respiratory secretions of sick individuals, it is not just those working in pediatrics who are potentially at an increased risk of exposure to respiratory pathogens including pneumococcus.…”