Staphylococcus aureus screening and preoperative decolonisation with Mupirocin and Chlorhexidine to reduce the risk of surgical site infections in orthopaedic surgery: a pre-post study.

BACKGROUND: Nasal carriage of Staphylococcus aureus is a risk factor for surgical site infections (SSI) in orthopaedic surgery. The efficacy of decolonisation for S. aureus on reducing the risk of SSI is uncertain in this speciality. The objective was to evaluate the impact of a nasal screening strategy of S. aureus and targeted decolonisation on the risk of S. aureus SSI. METHODS: A retrospective pre-post and here-elsewhere study was conducted between January 2014 and June 2020 in 2 adult orthopaedic surgical sites (North and South) of a French university hospital. Decolonisation with Mupirocin and Chlorhexidine was conducted in S. aureus carriers starting February 2017 in the South site (intervention group). Scheduled surgical procedures for hip, knee arthroplasties, and osteosyntheses were included and monitored for one year. The rates of S. aureus SSI in the intervention group were compared to a historical control group (South site) and a North control group. The risk factors for S. aureus SSI were analysed by logistic regression. RESULTS: A total of 5,348 surgical procedures was included, 100 SSI of which 30 monomicrobial S. aureus SSI were identified. The preoperative screening result was available for 60% (1,382/2,305) of the intervention group patients. Among these screenings, 25.3% (349/1,382) were positive for S. aureus and the efficacy of the decolonisation was 91.6% (98/107). The rate of S. aureus SSI in the intervention group (0.3%, 7/2,305) was not significantly different from the historical control group (0.5%, 9/1926) but differed significantly from the North control group (1.3%, 14/1,117). After adjustment, the risk factors of S. aureus SSI occurrence were the body mass index (ORaper unit, 1.05; 95%CI, 1.0-1.1), the Charlson comorbidity index (ORaper point, 1.34; 95%CI, 1.0-1.8) and operative time (ORaper minute, 1.01; 95%CI, 1.00-1.02). Having benefited from S. aureus screening/decolonisation was a protective factor (ORa, 0.24; 95%CI, 0.08-0.73). CONCLUSIONS: Despite the low number of SSI, nasal screening and targeted decolonisation of S. aureus were associated with a reduction in S. aureus SSI.

The frequency and associated factors of typhoid carriage in patients undergoing cholecystectomy for gallbladder disease in Pakistan: A cross-sectional study.

BACKGROUND: Enteric fever is caused by Salmonella enterica serovars Typhi (S. Typhi) and Paratyphi A, B, and C. It continues to be a significant cause of morbidity and mortality worldwide. In highly endemic areas, children are disproportionately affected, and antimicrobial resistance reduces therapeutic options. It is estimated that 2-5% of enteric fever patients develop chronic asymptomatic infection. These carriers may act as reservoirs of infection; therefore, the prospective identification and treatment of carriers are critical for long-term disease control. We aimed to find the frequency of Salmonella Typhi carriers in patients undergoing cholecystectomy. We also compared the detection limit of culturing versus qPCR in detecting S. Typhi, performed a geospatial analysis of the carriers identified using this study, and evaluated the accuracy of anti-Vi and anti-YncE in identifying chronic typhoid carriage. METHODS: We performed a cross-sectional study in two centers in Pakistan. Gallbladder specimens were subjected to quantitative PCR (qPCR) and serum samples were analyzed for IgG against YncE and Vi by ELISA. We also mapped the residential location of those with a positive qPCR result. FINDINGS: Out of 988 participants, 3.4% had qPCR-positive gallbladder samples (23 S. Typhi and 11 S. Paratyphi). Gallstones were more likely to be qPCR positive than bile and gallbladder tissue. Anti-Vi and YncE were significantly correlated (r = 0.78 p<0.0001) and elevated among carriers as compared to qPCR negative controls, except for anti-Vi response in Paratyphi A. But the discriminatory values of these antigens in identifying carriers from qPCR negative controls were low. CONCLUSION: The high prevalence of typhoid carriers observed in this study suggests that further studies are required to gain information that will help in controlling future typhoid outbreaks in a superior manner than they are currently being managed.

Imbalanced IL10/TGF-ß production by regulatory T-lymphocytes in patients with HTLV-1-associated myelopathy/ tropical spastic paraparesis.

BACKGROUND: Human T-cell lymphotropic virus type 1 (HTLV-1), also denominated Human T-cell leukemia virus-1, induces immune activation and secretion of proinflammatory cytokines, especially in individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Regulatory T lymphocytes (Tregs) may control of inflammation through the production of regulatory cytokines, including IL10 and TGF-ß. In this study we determined the frequencies of CD4 + and CD8 + Tregs in a HAM/TSP population, compared to asymptomatic carriers and uninfected individuals, as well as investigated the profiles of regulatory and inflammatory cytokines. METHODS: Asymptomatic HTLV-1 carriers and HAM/TSP patients were matched by sex and age. The frequencies of IL10- and/or TGF-ß-producing Tregs were quantified by flow cytometry. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to quantify HTLV-1 proviral load and the mRNA expression of cytokines and cellular receptors in peripheral blood mononuclear cells. RESULTS: Total frequencies of CD4 + Tregs, as well as the IL10-producing CD4 + and CD8 + Treg subsets, were statistically higher in patients with HAM/TSP compared to asymptomatic HTLV-1-infected individuals. In addition, a positive correlation was found between the frequency of CD4 + IL10 + Tregs and proviral load in the HAM/TSP patients evaluated. A positive correlation was also observed between gene expression of proinflammatory versus regulatory cytokines only in HAM / TSP group. CONCLUSIONS: A higher frequencies of IL10-producing Tregs were identified in patients with HAM/TSP. Imbalanced production of IL10 in relation to TGF-ß may contribute to the increased inflammatory response characteristically seen in HAM/TSP patients.

Nasal carriage rate, associated factors, and antimicrobial susceptibility patterns of methicillin resistance Staphylococcus aureus among pre-clinical undergraduate students at the College of Health and Medical Sciences, Haramaya University, Ethiopia.

Background: Staphylococcus aureus nasal carriage has been linked to higher rates of infection and morbidity. People with Methicillin-resistant Staphylococcus aureus can be a potential source of infection for others. University students living together in crowded conditions increase their risk of acquiring infections. The prevalence of S. aureus, particularly Methicillin-resistant Staphylococcus aureus nasal carriage, in Ethiopian university students is sparse. Objective: This study aimed to determine the nasal carriage rate, associated factors, and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus among pre-clinical students at the College of Health and Medical Sciences, Haramaya University, Ethiopia, from 1 July to 30 August 2022. Methods: An institutional-based cross-sectional study was conducted among 270 randomly selected pre-clinical Health and Medical Sciences students. Data on associated factors were collected using pre-tested, structured questionnaires. A nasal swab was taken from each participant and sent to the microbiology laboratory via Amies transport media in a cold chain. There, it was cultivated using conventional techniques. The isolated colonies were found to be S. aureus, and its antimicrobial susceptibility was performed using the Kirby-Bauer disk diffusion method on Muller-Hinton agar. Methicillin-resistant Staphylococcus aureus expressing using cefoxitin based on CLSI breakpoint. Data were entered into Epi-Data version 4.4.2.1 and exported to the Statistical Package for Social Sciences (SPSS) software version 25 for analysis. Pearson's chi-square test was performed to predict the associations between variables. A p-value less than 0.05 was regarded as statistically significant. Result: Methicillin-resistant Staphylococcus aureus nasal carriage was 5.9% (95% CI: 3.09-8.7) of cases of S. aureus nasal colonization, which was found to be 12.96% (95% CI: 8.85-16.96). Methicillin-resistant Staphylococcus aureus nasal colonization was significantly associated with the history of cigarette smoking (p = 0.000), intake of khat (p = 0.042), nose-picking habit (p = 0.003), history of sharing personal goods (p = 0.021), and history of hospitalizations (p = 0.00). All of the Methicillin-resistant Staphylococcus aureus isolates were resistant to ampicillin and cefoxitin. Conclusion: Based on the findings, a considerable proportion of healthy students harbored Methicillin-resistant Staphylococcus aureus strains associated with behavioral factors. Furthermore, these isolates showed high resistance to cefoxitin and ampicillin. Hence, it is crucial to regularly test pre-clinical students to prevent endogenous infections and the spread of Methicillin-resistant Staphylococcus aureus.

Staphylococcus aureus carriage and prevalence of skin and soft tissue infections among people who inject drugs: a longitudinal study.

People who inject drugs are frequently colonized with Staphylococcus aureus and have an increased risk for skin and soft tissue infections. This longitudinal study aims to describe S. aureus carriage in this group and the risk for infections during a 1-year follow-up. We included 61 participants from the Malmö Needle Exchange Program. Mapping of S. aureus carriage was conducted by screening cultures every third month and S. aureus growth was semi-quantified. Data regarding infections and living conditions were collected from structured interviews. Statistics included univariate analysis with the Fischer's exact test, univariate logistic regression and multivariate logistic regression. S. aureus carriage was detected in 46-63% of participants, and 75% reported one or more infections during the study period. Self-reported infections were associated with carriage in perineum (OR 5.08 [95% CI 1.45-17.73]), in skin lesions (OR 1.48 [95% CI 1.21-1.81]), and unstable housing situation (OR 12.83 [95% CI 1.56-105.81]). Thus, people who inject drugs are frequent carriers of S. aureus and report a surprisingly high prevalence of skin and soft tissue infections. Homeless people and those with skin carriage seem to be at highest risk. Effective clinical interventions are needed, aiming at preventing infections in this vulnerable group.

Nasal carriage of Staphylococcus aureus in healthy dairy cows in Algeria: antibiotic resistance, enterotoxin genes and biofilm formation.

BACKGROUND: Staphylococcus aureus can colonize and infect a variety of animal species. In dairy herds, it is one of the leading causes of mastitis cases. The objective of this study was to characterize the S. aureus isolates recovered from nasal swabs of 249 healthy cows and 21 breeders of 21 dairy farms located in two provinces of Algeria (Tizi Ouzou and Bouira). METHODS: The detection of enterotoxin genes was investigated by multiplex PCRs. Resistance of recovered isolates to 8 antimicrobial agents was determined by disc-diffusion method. The slime production and biofilm formation of S. aureus isolates were assessed using congo-red agar (CRA) and microtiter-plate assay. Molecular characterization of selected isolates was carried out by spa-typing and Multi-Locus-Sequence-Typing (MLST). RESULTS: S. aureus was detected in 30/249 (12%) and 6/13 (28.6%) of nasal swabs in cows and breeders, respectively, and a total of 72 isolates were recovered from positive samples (59 isolates from cows and 13 from breeders). Twenty-six of these isolates (36.1%) harbored genes encoding for staphylococcal enterotoxins, including 17/59 (28.8%) isolates from cows and 9/13 (69.2%) from breeders. Moreover, 49.1% and 92.3% of isolates from cows and breeders, respectively, showed penicillin resistance. All isolates were considered as methicillin-susceptible (MSSA). Forty-five (76.3%) of the isolates from cows were slime producers and 52 (88.1%) of them had the ability to form biofilm in microtiter plates. Evidence of a possible zoonotic transmission was observed in two farms, since S. aureus isolates recovered in these farms from cows and breeders belonged to the same clonal lineage (CC15-ST15-t084 or CC30-ST34-t2228). CONCLUSIONS: Although healthy cows in this study did not harbor methicillin-resistant S. aureus isolates, the nares of healthy cows could be a reservoir of enterotoxigenic and biofilm producing isolates which could have implications in human and animal health.

Correlation between carriers of Methicillin-resistant Staphylococcus aureus and the incidence of MRSA surgical site infections in orthopedic surgery patients.

OBJECTIVE: Surgical site infection (SSI) is a devastating complication in orthopedic surgery. Methicillin-resistant Staphylococcus aureus (MRSA) is a notorious organism in SSI, especially in orthopedic patients. We aimed to understand the association between MRSA carriers and the rate of SSI caused by MRSA in orthopedic patients. PATIENTS AND METHODS: We prospectively performed a cohort investigation on patients admitted to the Department of Orthopedic between April and August 2023. Samples were taken preoperatively from the nose and post-operatively in surgical wounds. All samples were grown in MeReSa Agar and defined as positive with MRSA characteristics. Data analysis was performed using SPSS Statistics. A significant difference between groups was assessed using either the Chi-square test or Fisher's exact test. Statistical significance was set at p<0.05. RESULTS: We obtained 526 nasal swabs of patients, and 140 (26.6%) samples were positive for MRSA. Our study revealed significant associations between MRSA carriers and the following factors: history of recent hospitalization (OR: 1.81; 95% CI: 1.172-2.795; p=0.007), smoking history (OR: 1.55; 95% CI: 1.011-2.383; p=0.044), and antibiotic exposures (OR: 2.19; 95% CI: 1.305-3.703; p=0.003). Our findings showed a significant association between SSI and the following factors: history of antibiotic exposures (OR: 2.89; 95% CI: 1.264-6.566; p=0.003), blood loss volume >500 ml (OR: 2.522; 95% CI: 1.245-5.108; p=0.008) and contaminated surgical wounds (OR: 5.97; 95% CI: 2.907-12.266; p=0.001). Patients with MRSA carriers tended to have an increased risk of having an MRSA SSI with an odds ratio of 3.44 (95% CI: 1.13-10.48; p=0.047). CONCLUSIONS: Our study highlights the increased risk of MRSA carriage in patients with a history of smoking, recent hospital admission, or antibiotic exposure. Our reports also identify potential risk factors for SSI, such as previous antibiotic exposure, blood loss, and contaminated wounds. Furthermore, our research establishes an association between MRSA colonization and MRSA SSI, which emphasizes the criticality of decolonization strategies. A further prospective multicenter study is needed to elaborate on our study findings.

In search of the best method to detect carriage of carbapenem-resistant Pseudomonas aeruginosa in humans: a systematic review.

BACKGROUND: Detection of carbapenem-resistant Pseudomonas aeruginosa (CR-PA) in humans is important to prevent transmission. However, the most optimal culture method to detect CR-PA is unknown. This systematic review aims to determine which culture method is most sensitive and which culture methods are used to detect CR-PA in humans. Second, to establish the most feasible culture method taking into account the turnaround time (TAT), and third, to provide an overview of the sampling sites used to detect carriage. METHODS: We systematically searched the electronic databases Embase, Medline Ovid, Cochrane, Scopus, CINAHL, and Web of Science until January 27, 2023. All diagnostic accuracy studies comparing two or more culture methods to detect CR-PA and recent outbreak or surveillance reports on CR-PA carriage or infection in humans, which describe culture methods and their results, were eligible for inclusion. We used QUADAS-2 guideline for diagnostic accuracy studies and the STROBE or ORION guideline for outbreak-surveillance studies to assess the risk of bias. RESULTS: Six diagnostic accuracy studies were included. An enrichment broth was found to increase the detection of CR-PA. Using an enrichment broth extended the TAT by 18-24 h, yet selective media could reduce the TAT by 24 h compared to routine media. In total, 124 outbreak-surveillance studies were included, of which 17 studies with surveillance samples and 116 studies with clinical samples. In outbreak-surveillance studies with surveillance samples, perianal, rectal swabs or stools were the most common sampling site/specimen (13/17, 76%). A large variety was observed in whether and which kind of enrichment broth and selective media were used. CONCLUSIONS: We found a benefit of using an enrichment step prior to inoculation of the material onto selective media for the detection of CR-PA. More research is needed to determine the most sensitive sampling site and culture method. TRAIL REGISTRATION: This study was registered in the PROSPERO International prospective register of systematic reviews (registration number: CRD42020207390, http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42020207390 ).

Staphylococcus aureus: No ticket for the Paris 2024 Olympic Games!

Athletes are vulnerable to Staphylococcus aureus infections due to skin-to-skin contact and skin abrasions during training and competitions involving sharied sport equipment or toiletries, which promote the spread of the bacteria between athletes and within sport teams. This results not only in higher prevalence of S.aureus carriage among athletes compared to the general population, but also in outbreaks of infections, particularly skin infections, within sports teams. To limit the spread of S. aureus among athletes, a decolonization protocol can be applied when clustered cases of S. aureus infections occur, especially if Panton-Valentine leukocidin-producing strains are implicated. Finally, to avoid exposing athletes to S.aureus transmission/colonization, it is recommended to establish strict and clearly formulated individual and collective hygiene rules and to regularly disinfect shared sports equipment.

Period prevalence of uveitis in human T-lymphotropic virus 1 carriers versus noncarriers in a highly endemic area: The Nagasaki Islands Study.

The magnitude of the effect of human T-lymphotropic virus 1 (HTLV-1) infection on uveitis remains unclear. We conducted a cross-sectional study in a highly endemic area of HTLV-1 in Japan. The study included 4265 residents (men, 39.2%), mostly middle-aged and older individuals with a mean age of 69.9 years, who participated in our surveys between April 2016 and September 2022. We identified HTLV-1 carriers by screening using chemiluminescent enzyme immunoassays and confirmatory tests, and the proportion of carriers was 16.1%. Participants with uveitis were determined from the medical records of all hospitals and clinics where certified ophthalmologists practiced. We conducted logistic regression analyses in an age- and sex-adjusted model to compute the odds ratio (OR) and 95% confidence interval (CI) of uveitis according to HTLV-1 infection status. Thirty-two (0.8%) participants had uveitis. For HTLV-1 carriers, the age- and sex-adjusted OR (95% CI) of uveitis was 3.27 (1.57-6.72) compared with noncarriers. In conclusion, HTLV-1 infection was associated with a higher risk of uveitis among mostly middle-aged and older Japanese residents in a highly endemic HTLV-1 area. Our findings suggest that physicians who treat HTLV-1 carriers should assess ocular symptoms, and those who diagnose patients with uveitis should consider HTLV-1 infection.

Staphylococcal carriage among captive dingoes (Canis dingo) in Victoria, Australia.

The evolutionary lineage and taxonomy of the Australian dingo is controversial, however recent genomic and gut metagenomic research has suggested that dingoes are evolutionarily distinct from modern dogs. Staphylococcus species are known commensal organisms of dogs and other mammals. In this study we took the opportunity to determine the carriage rate and antimicrobial resistance profiles of Staphylococcus species from 15 captive Australian dingoes. S. pseudintermedius was the only coagulase-positive species recovered, isolated from 6/15 (40%) and 9/13 (69%) of the animals during the 2020 (winter) and 2021 (summer) sampling times, respectively. Twenty-three coagulase-negative isolates were characterised, with S. equorum being the most frequently (20/23, 87%) recovered species. Two isolates of S. equorum had their genomes sequenced to learn more about this species. Antimicrobial resistance amongst both coagulase-positive and -negative isolates was low; with resistance to only 3 of 12 antimicrobials observed: penicillin, erythromycin, and trimethoprim. We have shown that the Australian dingo is a host organism for S. pseudintermedius much like it is in dogs, however the carriage rate was lower than has previously been reported from dogs in Australia.

Salmonella carriage and change in serovar distribution in broiler giblets at slaughterhouse level in Turkiye: first report using ISO 6579-1:2017 and ISO 6579-3:2014.

This study aimed to determine the prevalence and serovar distribution of salmonellae in liver, heart, and spleen (LHS) and gizzard (G) of slaughtered broilers. For this, a total of 60 sample units, comprised of 30 LHS and 30 G collected from 3 slaughterhouses, were analysed by reference methods for detection and serotyping as revised ISO 6579-1:2017 and ISO 6579-3:2014, respectively. Also, Salmonella-specific real-time PCR (Salm-PCR) was used for species confirmation, while Salmonella Enteritidis (S. Enteritidis) and Salmonella Typhimurium (S. Typhimurium) specific real-time PCR (SE/ST-PCR) was evaluated to determine its efficiency for rapid detection of the serovars mandated in current legal regulations compared to standard serotyping. All LHS (100%-30/30) and 90% (27/30) of G samples harbored Salmonella with an overall prevalence of 95% (57/60) in samples examined, where all isolates were confirmed as Salmonella by Salm-PCR. The most prevalent serovar in broiler giblets was S. Virchow (80.70%-46/57) followed by S. Enteritidis (19.30%-11/57). SE/ST-PCR (%17.54-10/57) could not detect one G isolate, which was serotyped as S. Enteritidis by standard serotyping. High relative accuracy (98.25%), sensitivity (100%) and specificity (100%), and agreement between methods (κ: 0.94) verified SE/ST-PCR's potential to be used as an alternative in rapid detection of S. Enteritidis and S. Typhimurium. Data on high Salmonella prevalence in broiler giblets of slaughterhouse origin, and detection of the pathogen by the implementation of all requirements indicated in the revised ISO 6579-1:2017 standard method, enabling the determination of actual prevalence in the samples with high sensitivity and specificity is of significance for public health. Additionally, identification of S. Virchow as the dominant serovar followed by S. Enteritidis with a relatively lower prevalence, and absence of S. Typhimurium in broiler giblets are important findings for Turkiye. This up to date data, obtained by strict application of ISO 6579-3:2014 procedures, indicated a shift in circulating serovars in the broiler industry. The objective findings in this study would bring awareness to national/international literature, and may be of use in future improvements in legal regulations.

Is Streptococcus pyogenes a pathogen or passenger in uncomplicated acute sore throat? A systematic review and meta-analysis.

OBJECTIVES: The objective was to estimate the probability that finding a Streptococcus pyogenes (Group A Streptococcus) in a throat swab in a patient with a sore throat reflects the aetiology. We also investigated to what extent this is influenced by age, carrier rates of S. pyogenes and climate zone. METHODS: We conducted a comprehensive search of Medline and Scopus up until October 2023 for case-control studies reporting the prevalence of S. pyogenes in patients with a sore throat and healthy controls. We only included studies with separate data for children and adults. We used the positive and negative etiologic predictive values (P-EPV and N-EPV) to estimate the probability of a link between a sore throat and a finding of S. pyogenes. RESULTS: We included 15 studies in our meta-analysis. The overall P-EPV for children and adults were 63% (49-74%) and 92% (87-95%), respectively. The P-EPV rose to 83% (64-93%) for children and 94% (90-97%) for adults when only patients with 3-4 Centor criteria were included. The overall N-EPV was 97% (96-98%) for children and 96% (95-97%) for adults. CONCLUSION: Detecting S. pyogenes in adult patients with an uncomplicated acute sore throat is useful to rule in S. pyogenes as the likely aetiologic agent. The P-EPV significantly increased for children when those with 3-4 Centor criteria were selected. A negative throat swab is always useful for both children and adults to rule out S. pyogenes as the cause of sore throat.

Confirmation of the invasive American mink (Neogale vison) as carrier of Mycobacterium bovis in southern Chile.

Bovine tuberculosis (bTB) is a chronic infectious-contagious disease with worldwide distribution, caused by the zoonotic pathogen Mycobacterium bovis. It is believed that the existence of wild cycles may hamper the success of bTB control strategies worldwide, where wildlife species could be reservoirs of this bacterial agent across their native (e.g., European badgers, wild boars) or non-indigenous (e.g., brushtail possum in New Zealand) ranges. However, further studies are required to understand the potential risk posed by non-native wildlife in becoming carriers of M. bovis in other neglected latitudes, such as the Southern Cone of South America. In this study, we performed a specific M. bovis-RD4 real-time PCR (qPCR) assay to detect bacterial DNA in tissues from the invasive American mink (Neogale vison) in Los Ríos region, Chile. We detected M. bovis DNA in blood samples collected from 13 out of 186 (7 %) minks with known sex and age. We did not find any significant differences in bacterial DNA detection according to mink sex and age. We found that 92 % (12/13) of specimens were positive in lung, 39 % (5/13) in mediastinal lymph node, and 15 % (2/13) in mesenteric lymph node, which suggest that both respiratory and digestive pathways as possible routes of transmission between infected hosts and minks. Our study is the first report on M. bovis molecular detection in invasive minks in an area where the largest cattle population in the country is located. Furthermore, this area is characterized by a low within-herd prevalence of M. bovis infection in cattle, with a relatively low number of infected herds, and so far, no attempts at eradicating the disease have been successful.

Tonsillectomies are associated with an increased risk of meningococcal carriage.

BACKGROUND: Neisseria meningitidis is a commensal organism with the potential to cause life-threatening disease. Colonisation is most common in adolescence and young adulthood. Various social factors have been associated with an increased risk of meningococcal carriage, but less is known about host factors that may influence the carriage status. Tonsillectomies have been shown to alter the pharyngeal microflora. This study assessed whether a history of tonsillectomy affects the risk of meningococcal colonisation. METHODS: Oropharyngeal swabs were collected from 15- to 16-year-old adolescents and 18- to 20-year-old young adults. Conventional culture methods and qPCR were used to detect meningococci. 16S qPCR was done to assess bacterial abundance in the samples. Data on history of tonsillectomies were collected from a central national database and the national university hospital. RESULTS: A total of 722 samples were collected; 197 from adolescents and 525 from young adults. Thirty-five participants were colonised with meningococci (4.8%). Eighty-eight participants had undergone a tonsillectomy, of which 10 (11.4%) carried meningococci, compared to 4% of those that had not. Prior tonsillectomy was associated with a threefold increased risk of meningococcal colonisation (OR 3.10, 95% CI 1.44-6.70, p = 0.004). Tonsillectomies remained a risk factor after adjusting for age, sex, recent antibiotic use and meningococcal vaccinations (aOR 2.49, 95% CI 1.13-5.48, p = 0.024). CONCLUSIONS: A history of tonsillectomy is associated with an increased risk of meningococcal colonisation. More studies are needed to shed light on the effects of tonsillectomies on the pharyngeal microbiome.

Decline in pneumococcal vaccine serotype carriage, multiple-serotype carriage, and carriage density in Nepalese children after PCV10 introduction: A pre-post comparison study.

BACKGROUND: Carriage studies are an efficient means for assessing pneumococcal conjugate vaccine effect in settings where pneumococcal disease surveillance programmes are not well established. In this study the effect of 10-valent pneumococcal conjugate vaccine (PCV10) introduction on pneumococcal carriage and density among Nepalese children using a bacterial microarray and qPCR was examined. METHODS: PCV10 was introduced into the Nepalese infant immunisation schedule in August 2015. Nasopharyngeal swabs were collected from healthy Nepalese children in Kathmandu between April 2014 and December 2021. Samples were plated on blood agar, incubated overnight, and DNA extracted from plate sweeps. Pneumococcal serotyping was done using the Senti-SPv1.5 microarray (BUGS Bioscience, UK). DNA was extracted from swab media and qPCR performed for pneumococcal autolysin (lytA). RESULTS: A significant decline in prevalence of PCV10 serotypes was observed when comparing pre-PCV10 with post-PCV10 collection periods (36.5 %, 454/1244 vs 10.3 %, 243/2353, p < 0.0001). Multiple-serotype carriage was also observed to significantly decline when comparing pre-PCV10 with post-PCV10 periods (31.4 %, 390/1244 vs 22.2 %, 522/2353, p < 0.0001). Additionally, a significant decline in median pneumococcal density was observed when comparing pre-PCV10 with post-PCV10 periods (3.3 vs 3.25 log10 GE/ml, p = 0.0196). CONCLUSIONS: PCV10 introduction was associated with reduced, prevalence of all PCV10 serotypes, multiple serotype carriage, and pneumococcal carriage density.

Streptococcus pyogenes carriage and infection within households in The Gambia: a longitudinal cohort study.

BACKGROUND: Streptococcus pyogenes causes more than 500 000 deaths per year globally, which occur disproportionately in low-income and middle-income countries. The roles of S pyogenes skin and pharyngeal carriage in transmission are unclear. We aimed to investigate the clinical epidemiology and household transmission dynamics of both S pyogenes asymptomatic carriage and infection in a high-burden setting. METHODS: We did a 1-year prospective, longitudinal, household cohort study, recruiting healthy participants from households in Sukuta, The Gambia. Households were eligible if they comprised at least three members, including one child younger than 18 years, and were excluded if more than half of household members declined to participate. Households were identified by random GPS coordinates derived from census data. At monthly visits, pharyngeal and normal skin swabs were collected for S pyogenes culture, and sociodemographic data were recorded by interview. Incident pharyngitis and pyoderma infections were captured. Cultured isolates underwent emm genotyping. The primary outcome measures were incidence of S pyogenes carriage and disease. Additional outcomes were prevalence of S pyogenes skin and pharyngeal carriage, S pyogenes skin and pharyngeal clearance time, S pyogenes emm type, risk factors for carriage and disease events, household secondary attack rate, and emm-linked household transmission events. The study is registered on ClinicalTrials.gov, NCT05117528. FINDINGS: Between July 27, 2021, and Sept 28, 2022, 442 participants were enrolled from 44 households. The median age was 15 years (IQR 6-28) and 233 (53%) were female. We identified 17 pharyngitis and 99 pyoderma events and 49 pharyngeal and 39 skin S pyogenes carriage acquisition events. Mean monthly prevalence was 1·4% (95% CI 1·1-1·9) for S pyogenes pharyngeal carriage and 1·2% (0·9-1·6) for S pyogenes skin carriage. Incidence was 120 per 1000 person-years (95% CI 87-166) for S pyogenes pharyngeal carriage, 124 per 1000 person-years (90-170) for S pyogenes skin carriage, 51 per 1000 person-years (31-84) for S pyogenes pharyngitis, and 263 per 1000 person-years (212-327) for S pyogenes pyoderma. Pharyngeal carriage risk was higher during the rainy season (HR 5·67, 95% CI 2·19-14·69) and in larger households (per additional person: 1·03, 1·00-1·05), as was pharyngitis risk (rainy season: 3·00, 1·10-8·22; household size: 1·04, 1·02-1·07). Skin carriage risk was not affected by season or household size, but was lower in female than in male participants (0·45, 0·22-0·92) and highest in children younger than 5 years compared with adults (22·69, 3·08-167·21), with similar findings for pyoderma (female sex: 0·34, 0·19-0·61; age <5 years: 7·00, 2·78-17·64). Median clearance time after carriage acquisition was 4·0 days for both skin (IQR 3·5-7·0) and pharynx (3·5-7·3). The mean household secondary attack rate was 4·9 (95% CI 3·5-6·3) for epidemiologically linked S pyogenes events and 0·74 (0·3-1·2) for emm-linked S pyogenes events. Of the 204 carriage and disease events, emm types were available for 179 (88%). Only 18 emm-linked between-visit household transmission events were identified. Pyoderma was the most common source of S pyogenes household transmissions in 11 (61%) of 18 emm-linked transmissions. Both pharynx to skin and skin to pharynx transmission events were observed. INTERPRETATION: S pyogenes carriage and infection are common in The Gambia, particularly in children. Most events are non-household acquisitions, but skin carriage and pyoderma have an important role in S pyogenes household transmission and bidirectional transmission between skin and pharynx occurs. FUNDING: Wellcome Trust, Chadwick Trust, Fonds National de la Recherche Scientifique (Belgium), European Society for Paediatric Infectious Diseases, and Medical Research Council (UK).

Global epidemiological comparison of Streptococcus pyogenes emm-types associated with pharyngitis and pharyngeal carriage.

OBJECTIVES: To test the prevailing dogma that Streptococcus pyogenes emm-types that cause pharyngitis are the same as those associated with the carriage, using a global dataset. METHODS: Drawing on our systematic review of the global distribution of S. pyogenes emm-types and emm-clusters from 1990 to 2023, we compared the distribution and diversity of strains associated with pharyngitis and pharyngeal carriage, in the context of local United Nations Development Programme Human Development Index (HDI) values. RESULTS: We included 20 222 isolates from 71 studies done in 34 countries, with the vast majority of carriage strain data from studies in 'Low HDI' settings (550/1293; 43%). There was higher emm-type diversity for carriage than pharyngitis strains (Simpson Reciprocal Index of diversity 28.9 vs. 11.4). Compared with pharyngitis strains, carriage emm-types were disproportionately from emm-clusters E and D, usually described as 'generalist' or 'skin' strains. DISCUSSION: A limited number of studies have compared S. pyogenes strains from cases of pharyngitis compared with carriage. Our understanding of strains associated with carriage is the poorest for high-income settings. In low and medium HDI countries, we found greater strain associated with pharyngeal carriage than pharyngitis. Improving our understanding of S. pyogenes carriage epidemiology in the pre-vaccine era will help to decipher the direct and potential indirect effects of vaccines.