Multicenter study of pneumococcal carriage in children 2 to 4 years of age in the winter seasons of 2017-2019 in Irbid and Madaba governorates of Jordan

Abstract

Streptococcus pneumoniae is one of the leading causes of death worldwide. It disseminates through colonizers and causes serious infections. Aims of this study are to determine pneumococcal carriage rate, resistance, serotype distribution, and coverage of pneumococcal conjugate vaccines from children attending day care centers from Irbid and Madaba in Jordan. Nasopharyngeal swabs were collected from day care centers (DCCs) of healthy Jordanian children 2-4 years of age from four regions of Madaba (n = 596), and from eastern Irbid (n = 423). Swabs were cultivated on Columbia blood agar base supplemented with 5% sheep blood and incubated for 18-24 hours at 37˚C with 5% CO 2. Alpha-hemolytic isolates were tested for optochin sensitivity and bile solubility for identification. Isolates were analyzed for antimicrobial susceptibility by the Vitek2 system and E-test (BioMé rieux). Serotyping was performed using the Neufeld Quellung method. A total of 341 pneumococcal strains were isolated from 1019 nasopharyngeal (NP) samples of healthy children attending DCCs for two winter seasons from 2017-2019. Carriage rate in eastern Irbid for both seasons was 29.6% and for Madaba 37.9%. Resistance rates for Irbid and Madaba, respectively, were as follows: Penicillin (86.3%; 94.4%), erythromycin (57.0%; 78.2%), clindamycin (30.8%; 47.2%), trimethoprim-sulfamethoxazole (68.6%; 86.6%), and tetracycline (45.7%; 51.9%). Predominant serotypes for Irbid were 19F (20.8%), 23F (12.0%), 6A (10.4%), and 6B (9.6%); whereas for Madaba were 19F (24.5%), 14 (7.4%), 6A (6.9%) and 23F (6.5%). Serotype coverage of the thirteen valent pneumococcal conjugate vaccine (PCV13) was about 65% for both regions. Over 96% of isolates with PCV13 serotypes in this study were resistant to penicillin with the exception of serotypes 3 and 5. As a conclusion resistance and carriage rates among the age group 2 to 4 years reached an alarming rate especially among vaccine types, which can be controlled by pneumococcal conjugate vaccination strategies.

Urban and Rural Disparities in Pneumococcal Carriage and Resistance in Jordanian Children, 2015–2019

“…Streptococcus pneumoniae is an infectious agent that causes invasive and non-invasive infections, especially in low-income countries with low or minimum vaccination rates [ 1 , 2 , 3 ]; it is an opportunistic human-adapted pathogen transmitted by the nasopharynx, which is an ecological reservoir for this bacterium, mainly during the first few months of life [ 4 ]. This NP carriage present in healthy children in rates between 20 and 40%, and it is influenced by different risk factors, including day care center attendance, the size of day care center, living in close contact with siblings, living in urban or rural areas, previous antibiotic consumption within one month before sample collection, cigarette smoking within family members, overcrowding in households, and socioeconomic factors [ 5 , 6 , 7 ]. Furthermore, this NP carriage is subject to genomic changes during natural colonization [ 8 ], and is acquired at approximately 4–6 months of age [ 1 , 9 ].…”

“…Other studies on the impact of vaccination on racial disparities of IPD incidence showed a high reduction after the introduction of PCV7 and PCV13 [ 18 ]. However, pneumococcal studies published for Jordan concentrated only on rural areas, especially where no PCVs were available [ 1 , 5 , 19 ]. Furthermore, Jordan is a mixture of cultures, especially after the Gulf and Syrian wars, in addition to being home to a large number of other nationalities and refugees.…”

Urban and Rural Disparities in Pneumococcal Carriage and Resistance of Jordanian Children, 2015-2019

“…The resistance situation of the pneumococcal strains isolated from children colonizers was studied in other rural areas of Jordan previously. These rural areas were Ajlun in 2009-2010 with penicillin resistance rate of 84.0% (19), then was found to be 80.0% in 2014 for Wadi Alseer (1) as a rural area in the peripheries of Amman, then was found in the rural area of eastern Irbid with a rate of 86.3% in 2019 (5). Resistance rates found in this study for penicillin was found to be 95.8% as significantly higher (P< 0.05) than all rural areas tested before in Jordan.…”

“…It is also known as an opportunistic human-adapted pathogen transmitted by the nasopharynx as an ecological reservoir for this bacterium inhabiting the nasopharynx during the first few months of life (4). This NP-carriage is available in healthy children in rates between 20 to 40%, which is influenced by different risk factors including day care center attendance, size of day care center, living in close contact as siblings, living in urban or rural areas, previous antibiotic consumption within one month before sample collection, cigarette smoking, overcrowdings in households, and socioeconomic factors (5)(6)(7). Furthermore, NP-carriage is subject to genomic changes during natural colonization (8), and is acquired at approximately 4-6 months of age (1,9).…”

“…Other studies on the impact of vaccination on racial disparities of the IPD incidence showed that high reduction after the introduction of the PCV7 and PCV13 (18). However, pneumococcal studies published for Jordan were concentrated only on the rural areas, especially where no PCV were available (1,5,19). Furthermore, Jordan is a mixture of culture, especially after the Gulf and Syrian wars, in addition to the availability of other nationalities and refugees.…”