Streptococcus pneumoniae among the children of Aden, Yemen: a cross-sectional report of post-pneumococcal conjugate vaccine.

INTRODUCTION: Streptococcus pneumoniae cause a significant global health challenge. We aimed to determine nasopharyngeal carriage, serotypes distribution, and antimicrobial profile of pneumococci among the children of Aden. METHODOLOGY: A total of 385 children, aged 2-17 years, were included. Asymptomatic samples were randomly collected from children in selected schools and vaccination centers. Symptomatic samples were obtained from selected pediatric clinics. The nasopharyngeal swabs were tested for pneumococci using culture and real time polymerase chain reaction (RT-PCR). Serotyping was done with a pneumotest-latex kit and antimicrobial susceptibility was tested by disc diffusion and Epsilometer test. RESULTS: The total pneumococcal carriage was 44.4% and 57.1% by culture and RT-PCR, respectively. There was a statistically significant association between carriage rate and living in single room (OR = 7.9; p = 0.00001), sharing a sleeping space (OR = 15.1; p = 0.00001), and low monthly income (OR = 2.02; p = 0.007). The common serotypes were 19, 1, 4, 5, 2, and 23. The proportion of non-pneumococcal conjugate vaccine (non-PCV13) serotypes was 24%. Pneumococci were resistant to penicillin (96.5%), cefepime (15.8%), ceftriaxone (16.4%), and amoxicillin-clavulanate (0%). Erythromycin, azithromycin, and doxycycline had resistance rates of 48%, 31%, and 53.3%, respectively. CONCLUSIONS: A high pneumococcal carriage rate was observed in Yemeni children, particularly in low-income households and shared living conditions. There was significant penicillin resistance at meningitis breakpoint. Furthermore, non-PCV13 serotypes were gradually replacing PCV13 serotypes. The findings underscore the urgent need for enhanced surveillance and stewardship to improve vaccination and antibiotic policies in Yemen.

Nasopharyngeal carriage of Streptococcus pneumoniae in Latin America and the Caribbean: A systematic review and meta-analysis.

BACKGROUND: Streptococcus pneumoniae is a leading cause of morbidity and mortality globally, causing bacteremic pneumonia, meningitis, sepsis, and other invasive pneumococcal diseases. Evidence supports nasopharyngeal pneumococcal carriage as a reservoir for transmission and precursor of pneumococcal disease. OBJECTIVES: To estimate the pneumococcal nasopharyngeal burden in all age groups in Latin America and the Caribbean (LAC) before, during, and after the introduction of pneumococcal vaccine conjugate (PVC). METHODS: Systematic literature review of international, regional, and country-published and unpublished data, together with reports including data from serotype distribution in nasopharyngeal carriage in children and adults from LAC countries following Cochrane methods. The protocol was registered in PROSPERO database (ID: CRD42023392097). RESULTS: We included 54 studies with data on nasopharyngeal pneumococcal carriage and serotypes from 31,803 patients. In children under five years old, carriage was found in 41% and in adults over 65, it was 26%. During the study period, children under five showed a colonization proportion of 34% with PCV10 serotypes and 45% with PCV13 serotypes. When we analyze the carriage prevalence of PCV serotypes in all age groups between 1995 and 2019, serotypes included in PCV10 and those included in PCV13, both showed a decreasing trend along analysis by lustrum. CONCLUSION: The data presented in this study highlights the need to establish national surveillance programs to monitor pneumococcal nasopharyngeal carriage to monitor serotype prevalence and replacement before and after including new pneumococcal vaccines in the region. In addition, to analyze differences in the prevalence of serotypes between countries, emphasize the importance of approaches to local realities to reduce IPD effectively.

Antimicrobial resistance and genetic relatedness of Salmonella serotypes isolated from food, asymptomatic carriers, and clinical cases in Shiyan, China.

Salmonella is a primary cause of foodborne diseases globally. Despite food contamination and clinical infections garnering substantial attention and research, asymptomatic Salmonella carriers, potential sources of infection, have been comparatively overlooked. In this study, we conducted a comparative analysis of serotype distribution, antimicrobial resistance phenotypes, and genetic profiles of archived Salmonella strains isolated from food (26), asymptomatic carriers (41), and clinical cases (47) in Shiyan City, China. Among the 114 Salmonella strains identified, representing 31 serotypes and 34 Sequence Types (STs), the most prevalent serovars included Typhimurium, Derby, Enteritidis, Thompson, and London, with the most predominant STs being ST11, ST40, ST26, ST34, and ST155. Antimicrobial resistance testing revealed that all strains were only sensitive to meropenem, with 74.6% showing antimicrobial resistance (AMR) and 53.5% demonstrating multidrug resistance (MDR). Strains resistant to five and six classes of antibiotics were the most common. Pearson's chi-square test showed no statistically significant difference in the occurrence of AMR (p = 0.105) or MDR (p = 0.326) among Salmonella isolates from the three sources. Our findings underscore associations and diversities among Salmonella strains isolated from food, asymptomatic carriers, and clinical patients, emphasizing the need for increased vigilance towards asymptomatic Salmonella carriers by authorities.

Can habits and behaviors predict colonization by community-associated MRSA in patients admitted to a Brazilian hospital?

This study aimed to identify factors associated with colonization by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in adult patients admitted to a Brazilian hospital. This is a cross-sectional study, in which patients underwent a nasal swab and were asked about hygiene behavior, habits, and clinical history. Among the 702 patients, 180 (25.6%) had S. aureus and 21 (2.9%) MRSA. The factors associated with MRSA colonization were attending a gym (OR 4.71; 95% CI; 1.42 - 15.06), smoking habit in the last year (OR 2.37; 95% CI; 0.88 - 6.38), previous hospitalization (OR 2.18; CI 95%; 0.89 - 5.25), and shared personal hygiene items (OR 1.99; 95% CI; 0.71 - 5.55). At the time of admission, colonization by CA-MRSA isolates was higher than that found in the general population. This can be an important public health problem, already endemic in hospitals, whose factors such as those associated with habits (smoking cigarettes) and behaviors (team sports practice and activities in gyms) have been strongly highlighted. These findings may help developing infection control policies, allowing targeting patients on higher-risk populations for MRSA colonization.

Interaction of Neisseria meningitidis carrier and disease isolates of MenB cc32 and MenW cc22 with epithelial cells of the nasopharyngeal barrier.

Neisseria meningitidis (Nm, the meningococcus) is considered an asymptomatic colonizer of the upper respiratory tract and a transient member of its microbiome. It is assumed that the spread of N. meningitidis into the bloodstream occurs via transcytosis of the nasopharyngeal epithelial barrier without destroying the barrier layer. Here, we used Calu-3 respiratory epithelial cells that were grown under air-liquid-interface conditions to induce formation of pseudostratified layers and mucus production. The number of bacterial localizations in the outer mucus, as well as cellular adhesion, invasion and transmigration of different carrier and disease N. meningitidis isolates belonging to MenB:cc32 and MenW:cc22 lineages was assessed. In addition, the effect on barrier integrity and cytokine release was determined. Our findings showed that all strains tested resided primarily in the outer mucus layer after 24 h of infection (>80%). Nonetheless, both MenB:cc32 and MenW:cc22 carrier and disease isolates reached the surface of the epithelial cells and overcame the barrier. Interestingly, we observed a significant difference in the number of bacteria transmigrating the epithelial cell barrier, with the representative disease isolates being more efficient to transmigrate compared to carrier isolates. This could be attributed to the capacity of the disease isolates to invade, however could not be assigned to expression of the outer membrane protein Opc. Moreover, we found that the representative meningococcal isolates tested in this study did not damage the epithelial barrier, as shown by TEER measurement, FITC-dextran permeability assays, and expression of cell-junction components.

Carriage of antimicrobial-resistant Enterobacterales among pregnant women and newborns in Amhara, Ethiopia.

OBJECTIVES: Infections are one of the most common causes of neonatal mortality, and maternal colonization has been associated with neonatal infection. In this study, we sought to quantify carriage prevalence of extended-spectrum-beta-lactamase (ESBL) -producing and carbapenem-resistant Enterobacterales (CRE) among pregnant women and their neonates and to characterize risk factors for carriage in rural Amhara, Ethiopia. METHODS: We conducted a prospective cohort study nested in the Birhan field site. We collected rectal and vaginal samples from 211 pregnant women in their third trimester and/or during labor/delivery and perirectal or stool samples from 159 of their neonates in the first week of life. RESULTS: We found that carriage of ESBL-producing organisms was fairly common (women: 22.3%, 95% CI: 16.8-28.5; neonates: 24.5%, 95% CI: 18.1-32.0), while carriage of CRE (women: 0.9%, 95% CI: 0.1-3.4; neonates: 2.5%, 95% CI: 0.7-6.3) was rare. Neonates whose mothers tested positive for ESBL-producing organisms were nearly twice as likely to also test positive for ESBL-producing organisms (38.7% vs 21.1%, P-value = 0.06). Carriage of ESBL-producing organisms was also associated with Woreda (district) of sample collection and recent antibiotic use. CONCLUSION: Understanding carriage patterns of potential pathogens and antibiotic susceptibility among pregnant women and newborns will inform local, data-driven recommendations to prevent and treat neonatal infections.

Leptospira infection and carrier survey on rats from wet market areas in Kuala Lumpur, Malaysia.

BACKGROUND OBJECTIVES: Leptospirosis is an important zoonotic infection that has caused significant mortality and morbidity worldwide. This disease is endemic in Malaysia and as a developing tropical country, leptospirosis is concerning as it threatens Malaysian public health and the country's economic sectors. However, there is limited information on leptospirosis in Malaysia, especially regarding leptospiral seroepidemiology among carriers in Malaysia. Therefore, more epidemiological information on the source of the disease and reservoir are needed for better disease control and source intervention. The objectives of this study are to gather information on Leptospira infection and the carrier status of rats captured from selected wet markets of Kuala Lumpur metropolitan city in Malaysia. METHODS: Live rat trappings were performed in four major wet markets in Kuala Lumpur, namely, Pudu, Chow Kit, Datuk Keramat, and Petaling Street. Animal samplings were performed for 12 months in 2017, where blood and kidney samples were collected and tested for anti-leptospiral antibodies via Microscopic Agglutination Test (MAT) and pathogenic Leptospira screening via Polymerase Chain Reaction (PCR) amplification offlaB gene. RESULTS: MAT showed that 34.7% (n = 50/144) of the captured rats were positive for anti-leptospiral antibody of which the most prominent serovar was Malaya followed by a local strain, IMR LEP 175. In parallel, 50 rats were also positive for pathogenic Leptospira DNA. INTERPRETATION CONCLUSION: This study showed that there are persistent Leptospira infections among rats in Kuala Lumpur wet markets and these rats are important reservoir hosts for the bacteria.

Staphylococcus aureus nasal colonization and susceptibility profile to antimicrobials in hemodialysis patients using a protocol of seven collections.

BACKGROUND: Patients colonized with Staphylococcus aureus in their nasal passages have a higher risk of acquiring infection, especially if they are immunocompromised or have comorbidities such as chronic renal failure undergoing hemodialysis (HD). OBJECTIVE: This study aimed to report the prevalence of nasal carriage of S. aureus among HD patients utilizing a seven-week sampling protocol and to assess the susceptibility of these isolates to various antimicrobial agents. METHODS: Over seven consecutive weeks, nasal swab samples were collected from 47 HD patients, resulting in a total of 329 samples. The microorganisms were identified using biochemical methods and subjected to antimicrobial susceptibility testing via disk diffusion and microdilution techniques. RESULTS: Out of all the patients analyzed, 25 individuals (53.19%) were found to be colonized by S. aureus, with 21 of them displaying intermittent colonization. Additionally, 38% showed positive results for S. aureus in only the 6th or 7th week of sampling. Within the 58 isolates, 17.2% (n=10) exhibited methicillin (oxacillin)-resistance and 25.86% (n=15) displayed elevated vancomycin MIC values (2 µg/ml). Based on the results, daptomycin and gentamicin were found to be effective treatment options. However, 31% of the isolates (n=18) exhibited a MIC of 1 µg/ml for daptomycin. CONCLUSION: Over half of the patients were colonized by S. aureus, but mostly on an intermittent basis. The identification of oxacillin resistance and high vancomycin and daptomycin MICs serve as warnings for possible future complications in managing bacteremia caused by S. aureus in these patients.

An Investigation of Pediatric Case-patients With Invasive Haemophilus influenzae in Alaska, 2005-2011.

BACKGROUND: Haemophilus influenzae (Hi) can cause severe disease in children. This study aimed to identify risk factors related to invasive Hi disease in Alaska children and evaluate carriage in people around them. METHODS: From 2005 to 2011, we investigated episodes of invasive, typeable Hi disease in Alaska children <10 years old. Three age-matched control children were enrolled for each case-patient. We evaluated oropharyngeal Hi carriage in people in close contact with Hi case-patients (contacts) as well as control children and their household members. Individual and household risk factors for illness and carriage were evaluated using questionnaires and chart reviews. RESULTS: Thirty-eight of 44 (86%) children with invasive, typeable Hi disease were recruited: 20 Hi serotype a (53%), 13 serotype b (Hib) (34%) and 5 serotype f (13%). Children with the invasive Hi disease were more likely than controls to have underlying health problems (67% vs. 24%, P = 0.001), other carriers of any Hi in their household (61% vs. 15%, P < 0.001), and inadequate Hib vaccination (26% vs. 9%, P = 0.005). People who carried Hi were younger than noncarriers (mean 12.7 vs. 18.0 years, P = 0.008). The carriage was clustered within case-patient households, with carriage in 19% of household contacts, while only 6.3% of nonhousehold contacts and 5.5% of noncontacts carried the Hi serotype of interest ( P < 0.001). CONCLUSIONS: Factors associated with invasive Hi disease in children included underlying health problems, household carriage and inadequate Hib vaccination. The high level of carriage in case-patient households is important to consider when evaluating treatment and prophylaxis strategies.

Low usefulness of reporting tonsillar PCR Ct-values in pharyngeal infections with Fusobacterium necrophorum.

Tonsillar Fusobacterium necrophorum PCR Ct-values were higher in participants with asymptomatic tonsillar carriage than patients with pharyngeal infections. However, Ct-values were not associated with severity of disease or predictive of development of complications and hence lacked clinical usefulness. The reporting of F. necrophorum Ct-values in clinical samples is not recommended.

Prevalence, serogroup distribution and risk factors of Neisseria meningitidis carriage in high school and university students in Hungary.

Neisseria meningitidis causes life-threatening invasive meningococcal disease (IMD) with high mortality worldwide. Asymptomatic pharyngeal meningococcus colonisation is an important reservoir for the spread of the bacterium. The aim of this study was to determine N. meningitidis colonisation rates in asymptomatic high school and university students and to identify risk factors for carriage. Oropharyngeal swab samples and data from a self-reported questionnaire were obtained from overall 610 students, among them 303 university students and 307 high school students, aged between 15 and 31 years in Budapest, Hungary, between November 2017 and December 2018. Meningococcal carriage and serogroup of N. meningitidis were determined by RT-PCR from DNA extracted directly from the specimen. N. meningitidis was identified in 212 (34.8 %) of the participants. Significantly higher carriage rate was found among high school students (48.9 %) compared to university students (20.5 %). Peak of colonisation rate was among 17-19-year-old students (48.7 %). Most carriage isolates were non-typable (87.3 %). From the 212 meningococcus carriers, 19 were colonised by serogroup B (9 %), 5 by serogroup C (2.4 %), and 1 had serogroup Y (0.5 %). Significantly higher colonisation rate was found among males (42.4 %) than in females (33.1 %). Antibiotic use in the past 2 months has decreased the rate of meningococcal colonisation. Recent respiratory infection, active or passive smoking and attending parties have not influenced meningococcal colonisation rate significantly. In conclusion, we have found high asymptomatic meningococcus carriage rate among high school students and young adults, however, the majority of the colonizing meningococci were non-typable.

Effect of nasal carriage of Bacillus species on COVID-19 severity: a cross-sectional study.

Intranasal sprays containing Bacillus species are being researched for treating viral respiratory tract infections. The aim of this study was to assess the relationship between the nasal carriage of Bacillus and COVID-19 severity. This was a cross-sectional study that collected nasopharyngeal samples from adults 18 years and above visiting two COVID-19 testing centers in Lagos, Nigeria, between September 2020 and September 2021. Bacillus species were cultured from the samples and confirmed using 16 s rRNA gene sequencing. The dependent variable was COVID-19 status classified as negative, asymptomatic, mild, or severe. The independent variable was the nasal carriage of Bacillus species. Multinomial regression analysis was done to determine the association between nasal carriage of Bacillus and COVID-19 severity after adjusting for age, sex, and co-morbidity status. A total of 388 participants were included in the study with mean (standard deviation) age of 40.05 (13.563) years. Sixty-one percent of the participants were male, 100 (25.8%) had severe COVID-19, 130 (33.5%) had pre-existing comorbidity, and 76 (19.6%) had Bacillus cultured from their nasopharyngeal specimen. Bacillus species presence was significantly associated with higher odds of severe COVID-19 compared to having a negative COVID-19 status (AOR = 3.347, 95% CI: 1.359, 8.243). However, the presence of Bacillus species was significantly associated with lower odds of severe COVID-19 compared to having a mild COVID-19 status. The study suggests that nasal carriage of Bacillus species is associated with the clinical course of COVID-19 and supports the exploration of Bacillus species in the management of viral respiratory tract infections.IMPORTANCEWith the introduction of intranasal spray containing Bacillus species for the treatment of viral respiratory tract infections, such as COVID-19 and respiratory syncytial virus, identifying the association between the nasal carriage of Bacillus species and COVID-19 susceptibility and severity will help further substantiate the investigation of these bacteria for COVID-19 prevention and treatment. This study evaluated the association between the carriage of Bacillus species in the nasopharyngeal tract and COVID-19 severity and found that the presence of Bacillus species in the nasopharynx may significantly impact the clinical course of COVID-19.

Bacterial nasopharyngeal colonisation in children in South Africa before and during the COVID-19 pandemic: an observational study.

BACKGROUND: Deployment of non-pharmaceutical interventions such as face masking and physical distancing during the COVID-19 pandemic could have altered the transmission dynamics and carriage of respiratory organisms. We evaluated colonisation with Streptococcus pneumoniae and other upper respiratory tract bacterial colonisers before and during the COVID-19 pandemic. METHODS: We did two cross-sectional surveys in Soweto, South Africa from July 3 to Dec 13, 2018 (pre-COVID-19 period) and from Aug 4, 2021, to March 31, 2022 (COVID-19 period) in healthy children (aged ≤60 months) who had recorded HIV status and had not received antibiotics in the 21 days before enrolment. At enrolment, we collected nasopharyngeal swab samples from child participants. Following nucleic acid extraction, nanofluidic quantitative PCR was used to screen all samples for 92 S pneumoniae serotypes and 14 other bacteria. The primary objective was to compare the prevalence and density of pneumococcal nasopharyngeal colonisation, overall and stratified by 13-valent pneumococcal conjugate vaccine (PCV13) serotypes and non-vaccine serotypes. Secondary study objectives included a comparison of serotype-specific pneumococcal colonisation and density, as well as colonisation by the 14 other bacteria in the COVID-19 versus pre-COVID-19 period. We used an adjusted multiple logistic and linear regression model to compare the colonisation prevalence and density between study periods. FINDINGS: We analysed nasopharyngeal swabs from 1107 children (n=571 in the pre-COVID-19 period; n=536 in the COVID-19 period). We observed no change in overall pneumococcal colonisation between periods (274 [51%] of 536 in the COVID-19 period vs 282 [49%] of 571 in the pre-COVID-19 period; adjusted odds ratio [aOR] 1·03 [95% CI 0·95-1·12]). The prevalence of PCV13 serotypes was lower in the COVID-19 than in the pre-COVID-19 period (72 [13%] vs 106 [19%]; 0·87 [0·78-0·97]), whereas the prevalence of non-typeable S pneumoniae was higher (34 [6%] vs 63 [12%]; 1·30 [1·12-1·50]). The mean log10 density for overall pneumococcal colonisation was lower in the COVID-19 period than in the pre-COVID-19 period (3·96 [95% CI 3·85-4·07] vs 4·72 [4·63-4·80] log10 genome equivalents per mL; p<0·0001). A lower density of non-vaccine serotypes (3·63 [3·51-3·74] vs 4·08 [3·95-4·22] log10 genome equivalents per mL; p<0·0001) and non-typeable S pneumoniae (3·11 [2·94-3·29] vs 4·41 [4·06-4·75] log10 genome equivalents per mL; p<0·00001) was also observed in the COVID-19 period. There was no difference in the density of PCV13 serotypes between the periods. The prevalence of colonisation during the COVID-19 versus pre-COVID-19 period was lower for non-typeable Haemophilus influenzae (280 [49%] vs 165 [31%]; aOR 0·77 [95% CI 0·71-0·84]), Moraxella catarrhalis (328 [57%] vs 242 [45%]; 0·85 [0·79-0·92]), and Neisseria lactamica (51 [9%] vs 13 [2%]; 0·64 [0·52-0·78]), but higher for Acinetobacter baumannii (34 [6%] vs 102 [19%]; 1·55 [1·35-1·77]) and Staphylococcus aureus (29 [5%] vs 52 [10%]; 1·28 [1·10-1·50]). INTERPRETATION: There were variable effects on the colonisation prevalence and density of bacterial organisms during the COVID-19 compared with the pre-COVID-19 period. The lower prevalence of PCV13 serotype together with other respiratory organisms including non-typeable H influenzae and M catarrhalis could have in part contributed to a decrease in all-cause lower respiratory tract infections observed in South Africa during the initial stage of the COVID-19 pandemic. The pathophysiological mechanism for the increase in A baumannii and S aureus colonisation warrants further investigation, as does the clinical relevance of these findings. FUNDING: The Bill & Melinda Gates Foundation.

Prevalence, antimicrobial resistance, and genetic lineages of nasal Staphylococcus aureus among medical students at a Spanish University: detection of the MSSA-CC398-IEC-type-C subclade.

Medical students could be a potential source of Staphylococcus aureus transmission to patients. This cross-sectional study involved samples collected from both nasal nostrils. Samples were processed for S. aureus recovery; the antimicrobial resistance (AMR) phenotype was determined by disc diffusion assays and the spa types and AMR genotypes by PCR/sequencing. A structured questionnaire was administered to students to collate data related to potential risk factors of nasal colonization. Ninety-eight students were included, 50 % were colonized by S. aureus and 12.2 % by MRSA. The mecA gene was detected in all MRSA isolates. The MSSA-CC398-IEC-type C lineage was found among 16.3 % of nasal carriers, of which t571 was the predominant spa-type. MRSA isolates were ascribed to spa types t2226 (CC5, 12 isolates) and t3444 (new spa type, 1 isolate). All MRSA were multi-drug resistant and MSSA were predominantly resistant to erythromycin-clindamycin (inducible-type, mediated by ermT gene). High rates of S. aureus and MRSA nasal carriages were observed in this study. The predominance of the CC398 lineage among MSSA (emergent invasive lineage) represent a relevant finding of public health concern. The role of medical students as potential source of MRSA and MSSA-CC398 transmissions in hospital and community needs to be elucidated in detail.

Nasopharyngeal carriage of Streptococcus pneumoniae serotypes among sick and healthy children in northern India: A case-control study.

BACKGROUND: Streptococcus pneumoniae is leading bacterial cause of community acquired pneumonia and according to World Health Organization, responsible for 14 % death in children. There is effective vaccine available against Streptococcus pneumoniae. Hence the primary objective was to isolate Streptococcus pneumoniae from nasopharyngeal swabs in children aged 2-59 months with and without community acquired pneumonia and to assess their serotypes. METHODS: This case-control study was conducted in tertiary teaching institutes in northern India. Hospitalized children, aged 2-59 months, with World Health Organization-defined community acquired pneumonia were included as cases. Age matched healthy controls were recruited from immunization clinic. All enrolments were done after written informed parental consent. Nasopharyngeal swabs were taken from both cases and controls, and were cultured on 5 % sheep blood agar with gentamycin plate for growth of Streptococcus pneumoniae and incubated in a jar at 370 for 18-24 hrs. Quellung reaction test was used for serotyping. RESULTS: From March 2017 to December 2022, 2693 children (1910 cases and 783 controls), were recruited. The median age of cases was 7 months and controls 10 months. Almost all the cases had received antibiotics prior to hospitalization. Streptococcus pneumoniae positivity in nasopharyngeal swab was 8.1 % in cases, of which 56.8 % were vaccine serotypes and 23.6 % in controls, of which 37.8 % were vaccine serotypes. Adjusted odds ratio of isolating vaccine serotypes among cases as compared to controls was 1.77 (95 % CI, 1.09-2.88). CONCLUSION: Streptococcus pneumoniae isolation from nasopharyngeal was found to be in lower proportion in cases as compared to control, though colonization with vaccine serotypes was higher in cases as compared to control. Therefore, pneumococcal vaccine coverage must be increased to prevent community acquired pneumonia.

Pneumococcal serotypes and antibiotic resistance in healthy carriage children after introduction of PCV13 in Lima, Peru.

OBJECTIVE: To determinate the frequency of Streptococcus pneumoniae nasopharyngeal carriers, serotypes and antimicrobial resistance in healthy children in Lima, Peru, post-PCV13 introduction and to compare the results with a similar study conducted between 2006 and 2008 before PCV7 introduction (pre-PCV7). METHODS: A cross-sectional multicenter study was conducted between January 2018 and August 2019 in 1000 healthy children under two years of age. We use standard microbiological methods to determinate S. pneumoniae from nasopharyngeal swab, Kirby Bauer and minimum inhibitory concentration methods to determinate antimicrobial susceptibility and whole genomic sequencing to determinate pneumococcal serotypes. RESULTS: The pneumococcal carriage rate was 20.8 % vs. 31.1 % in pre-PCV7 (p < 0.001). The most frequent serotypes were 15C, 19A and 6C (12.4 %, 10.9 % and 10.9 % respectively). The carriage of PCV13 serotypes after PCV13 introduction decreased from 59.1 % (before PCV7 introduction) to 18.7 % (p < 0.001). Penicillin resistance was 75.5 %, TMP/SMX 75.5 % and azithromycin 50.0 %, using disk diffusion. Penicillin resistance rates using MIC breakpoint for meningitis (MIC ≥ 0.12) increased from 60.4 % to 74.5 % (p = 0.001). CONCLUSION: The introduction of PCV13 in the immunization program in Peru has decreased the pneumococcal nasopharyngeal carriage and the frequency of PCV13 serotypes; however, there has been an increase in non-PCV13 serotypes and antimicrobial resistance.

[Pneumococcal conjugate vaccines in pediatrics, its impact on Public Health]. / Vacunas conjugadas contra neumococo en pediatría, su impacto en la Salud Pública.

Streptococcus pneumoniae (also known as pneumococcus) is part of the natural bacterial flora of the nasal and pharyngeal mucosa, colonizes mainly the nasopharynx, and causes this carriage to precede pneumococcal disease, thus becoming the main source of propagation among people, especially in children. Since 1983, when the first 23-component anti-pneumococcal vaccine was authorized, different conjugated vaccines have been developed according to the circulating serotypes that cause invasive pneumococcal diseases (IPD), reducing the incidence and mortality of these diseases considerably. In November 2021, a group of experts held a virtual meeting to update and analyze the impact that pneumococcal vaccines have generated on the countries' public health, especially during the COVID-19 pandemic. The recommendations that emerged included the need to look for alternatives in serotype-independent vaccines after the introduction of pneumococcal conjugate vaccines (PCV) in the national immunization schedules, as well as to strengthen the surveillance of serotypes, focusing on those not included in the current vaccines. The objective of this report is to communicate the conclusions of the group of experts that in November 2021 analyzed the impact of pneumococcal vaccines on public health in the countries, in order to generate recommendations applicable in Latin America.

Streptococcus pneumoniae and other bacterial nasopharyngeal colonization seven years post-introduction of 13-valent pneumococcal conjugate vaccine in South African children.

OBJECTIVES: Pneumococcal conjugate vaccines (PCVs) reduce pneumococcal-associated disease by reducing vaccine-serotype (VT) acquisition in vaccinated children, thereby interrupting VT transmission. The 7-valent-PCV was introduced in the South African immunization program in 2009 (13-valent-PCV since 2011) using a 2+1 schedule (at 6, 14, and 40 weeks of age). We aimed to evaluate temporal changes in VT and non-vaccine-serotype (NVT) colonization after 9 years of childhood PCV immunization in South Africa. METHODS: Nasopharyngeal swabs were collected from healthy children <60-month-old (n = 571) in 2018 (period-2) and compared with samples (n = 1135) collected during early PCV7-introduction (period-1, 2010-11) in an urban low-income setting (Soweto). Pneumococci were tested for using a multiplex quantitative-polymerase chain reaction serotyping reaction-set. RESULTS: Overall pneumococcal colonization in period-2 (49.4%; 282/571) was 27.5% lower than period-1 (68.1%; 773/1135; adjusted odds ratio [aOR]: 0.66; 95% confidence interval [CI]: 0.54-0.88). Colonization by VT was reduced by 54.5% in period-2 (18.6%; 106/571) compared with period-1 (40.9%; 465/1135; aOR: 0.41; 95% CI: 0.3-0.56). Nevertheless, serotype 19F carriage prevalence was higher (8.1%; 46/571) in period-2 compared with period-1 (6.6%; 75/1135; aOR: 2.0; 95% CI: 1.09-3.56). NVT colonization prevalence was similar in period-2 and period-1 (37.8%; 216/571 and 42.4%; 481/1135). CONCLUSION: There remains a high residual prevalence of VT, particularly 19F, colonization nine years post-introduction of PCV in the South African childhood immunization program.

Staphylococcus aureus nasal colonization level and intracellular reservoir: a prospective cohort study.

Staphylococcus aureus is a major pathogen in humans. The nasal vestibule is considered as the main reservoir of S. aureus. However, even though the nasal cavity may also be colonized by S. aureus, the relationships between the two sites are still unclear. We conducted a prospective study in humans to assess the S. aureus colonization profiles in the vestibule and nasal cavity, and to investigate the presence of intracellular S. aureus in the two sites. Patients undergoing ear, nose, and throat surgery were swabbed during endoscopy to determine S. aureus nasal load, genotype, and presence of intracellular S. aureus. Among per-operative samples from 90 patients, the prevalence of S. aureus carriage was 32.2% and 33.3% in the vestibule and the nasal cavity, respectively. The mean S. aureus load was 4.10 and 4.25 log10 CFU/swab for the nasal vestibule and nasal cavity, respectively (P > 0.05). Genotyping of S. aureus revealed that all nasal strains isolated from a given individual belong to the same clonal complex and spa-type. An intracellular carriage was observed in 5.6% of the patients, all of whom exhibited a S. aureus vestibule load higher than 3 log10 CFU/swab. An intracellular niche was observed in the vestibule as well as in the nasal cavity. In conclusion, the nasal cavity was also found to be a major site of S. aureus carriage in humans and should draw attention when studying host-pathogen interactions related to the risk of infection associated with colonization.

Optimization of a high-throughput nanofluidic real-time PCR to detect and quantify of 15 bacterial species and 92 Streptococcus pneumoniae serotypes.

Sensitive tools for detecting concurrent colonizing pneumococcal serotypes are needed for detailed evaluation of the direct and indirect impact of routine pneumococcal conjugate vaccine (PCV) immunization. A high-throughput quantitative nanofluidic real-time PCR (Standard BioTools 'Fluidigm') reaction-set was developed to detect and quantify 92 pneumococcal serotypes in archived clinical samples. Nasopharyngeal swabs collected in 2009-2011 from South African children ≤ 5 years-old, previously serotyped with standard culture-based methods were used for comparison. The reaction-set within the 'Fluidigm' effectively amplified all targets with high efficiency (90-110%), reproducibility (R2 ≥ 0.98), and at low limit-of-detection (< 102 CFU/ml). A blind analysis of 1 973 nasopharyngeal swab samples showed diagnostic sensitivity > 80% and specificity > 95% compared with the referent standard, culture based Quellung method. The qPCR method was able to serotype pneumococcal types with good discrimination compared with Quellung (ROC-AUC: > 0.73). The high-throughput nanofluidic real-time PCR method simultaneously detects 57 individual serotypes, and 35 serotypes within 16 serogroups in 96 samples (including controls), within a single qPCR run. This method can be used to evaluate the impact of current PCV formulations on vaccine-serotype and non-vaccine-serotype colonization, including detection of multiple concurrently colonizing serotypes. Our qPCR method can allow for monitoring of serotype-specific bacterial load, as well as emergence or ongoing transmission of minor or co-colonizing serotypes that may have invasive disease potential.