Carriage prevalence of Neisseria meningitidis in the Americas in the 21st century: a systematic review

Asymptomatic nasopharyngeal carriage of multidrug resistant bacteria among children at University of Gondar Hospital Northwest Ethiopia Revealing Hidden Health Risks

Gram-negative bacteria in the nasopharynx can eventually invade bacteria-limited sites and cause serious illnesses such as meningitis, otitis media, and pneumonia. However, data related to the carriage of these bacteria in children attending outpatient departments in the study area are limited. To assess nasopharyngeal carriage, antibiotic susceptibility patterns, and associated factors of gram-negative bacteria among children attending the outpatient department at the University of Gondar Comprehensive Specialized Hospital, Northwest Ethiopia. A hospital-based cross-sectional study was conducted from September 1, 2023, to December 30, 2023. A total of 385 children aged 3 to 14 years were enrolled using a systematic random sampling technique. Sociodemographic and clinical data were collected using a semistructured questionnaire. A total of 385 nasopharyngeal samples were collected using a sterile specimen collection nasopharyngeal swab, transported using Amie's transport medium, and subsequently inoculated on chocolate agar, blood agar, modified thayer martin agar, and MacConkey agar plates. Bacterial species were identified by colony morphology, Gram staining, and biochemical tests such as oxidase tests, satellitism tests, and carbohydrate utilization tests. An antibiotic susceptibility test was performed using the Kirby-Bauer and modified Kirby-Bauer methods on Mueller-Hinton agar plates. The data were entered into Epi-Data version 4.6.0.6 and exported to SPSS version 25 for analysis. The adjusted odds ratio at a 95% confidence interval with a P value of < 0.05 in the binary logistic regression model was considered to indicate statistical significance. The overall nasopharyngeal carriage of gram-negative bacteria was 146 (37.9%) (95% CI: 33.2-42.9). Among these, nonfastidious gram-negative bacteria represented 45 (11.7%), followed by M. catarrhalis 41 (10.6%), N. meningitidis 34 (8.8%), and H. influenzae 26 (6.8%). The isolates exhibited high resistance to tetracycline (85; 75.9%), trimethoprim-sulfamethoxazole (105; 71.9%), ampicillin (76; 67.9%), and amoxicillin/clavulanic acid (60; 69.8%) but high susceptibility to meropenem (122; 83.6%), gentamicin (73; 84.9%), and minocycline (87; 72.5%). There were 99 total multidrug-resistant strains (67.8%, 95% CI: 59.7-75.0). Male sex (AOR = 1.785, 95% CI: 1.102-2.892, P = 0.019), smoking (AOR = 2.675, 95% CI: 1.149-6.230, P = 0.022), and large family size (≥ 5) (AOR = 1.857, 95% CI: 1.140-3.023, P = 0.013) were risk factors for nasopharyngeal colonization. Increased nasopharyngeal colonization of multidrug-resistant gram-negative isolates was observed in this study. Gentamicin, minocycline, and meropenem were the most effective antibiotics for the tested isolates. Bacterial colonization increased with increasing family size, smoking status, and male sex. Therefore, a definitive diagnosis in the outpatient pediatric department should be based on culture and susceptibility test results.

Non-serogroupable Neisseria meningitidis pneumonia in an immunocompetent patient with severe COVID-19 pneumonia: A case report

Background

Non-serogroupable Neisseria meningitidis (N. meningitidis), the most common type of N. meningitidis in asymptomatic carriers, rarely causes infections. Most reported cases of infection are in patients with immunodeficiency, primarily complement deficiencies.

Case presentation

A 54-year-old immunocompetent man was transferred to our hospital to treat severe coronavirus disease 2019 (COVID-19). The patient presented with cough producing a large amount of purulent sputum, which was considered an atypical presentation of COVID-19. Gram staining of the sputum revealed a large number of gram-negative diplococci phagocytosed by many neutrophils, and a diagnosis of bacterial pneumonia was established. The culture yielded non-serogroupable N. meningitidis, and the patient was diagnosed with non-serogroupable N. meningitidis pneumonia. Potential immunodeficiency was considered; however, testing including human immunodeficiency virus and complement factors showed no abnormalities.

Conclusions

We report herein a rare case of non-serogroupable N. meningitidis pneumonia that occurred in an immunocompetent patient during the course of severe COVID-19. We consider impaired T cell function attributable to COVID-19 and dexamethasone administration may have triggered a transient immunosuppressive state and led to non-serogroupable N. meningitidis pneumonia.

Demographic Features of Invasive Meningococcal Disease in Taiwan, 1993 to 2020, and Genetic Characteristics of Neisseria meningitidis Isolates, 2003 to 2020

We present the demographic features of invasive meningococcal disease (IMD) in Taiwan between 1993 and 2020 and the genetic characteristics of Neisseria meningitidis isolates recovered from 2003 to 2020. IMD was rare in Taiwan between 1993 and 2020, with an annual incidence ranging from 0.009 to 0.204 per 100,000 people. The case fatality rate (CFR) declined from 18.1% for patients in 1993 to 2002 to 9.8% in 2003 to 2020. Infants less than 12 months were most susceptible to the disease. N. meningitidis serogroup B (NmB) was most predominant, responsible for 81.2% (134/165) of the IMD cases in 2003 to 2020. The majority of the isolates recovered from 2003 to 2020 belonged to 4 worldwide-spread hyperinvasive clonal complexes (cc), cc4821 (30.3%), cc32 (19.4%), cc41/44 (12.7%), cc23 (7.3%), and also a newly assigned clonal complex, cc3439 (10.3%). Core genome multilocus sequence typing (cgMLST) profile comparisons revealed that the cc4821 isolates with a T-to-I substitution at position 91 in gyrA were closely related to those originating from China. Of the 165 isolates, 20.0% and 53.3% were predicted to be covered by the Bexsero and Trumenba vaccines, respectively, whereas, 77.0% and 46.7% remained indeterminate. In conclusion, N. meningitidis isolates recovered in Taiwan between 2003 and 2020 were mostly highly diverse. Most IMD cases appeared sporadically and were caused by localized strains, although some patients were infected by recently introduced strains. cgMLST is a powerful tool for the rapid comparison of genetic relatedness among a large number of isolates. cgMLST profiling, based on 1,241 core genes, and strain tracking can be performed on the website of cgMLST@Taiwan (http://rdvd.cdc.gov.tw/cgMLST/). IMPORTANCE N. meningitidis can cause life-threatening invasive meningococcal disease (IMD), including meningitis and sepsis, resulting in a high CFR and long-term sequelae in survivors. Here, we report the demographic features of IMD in Taiwan over a 28-year period (1993 to 2020) and the genetic characteristics of N. meningitidis isolates recovered from patients with IMD over an 18-year period (2003 to 2020). We conducted a whole-genome sequence analysis to characterize the genetic features of the isolates and developed a cgMLST scheme for epidemiological investigation and strain tracking. The findings can be beneficial in understanding the epidemiology of IMD in Taiwan, the genetic characteristics of the bacterial strains, and the distribution of vaccine antigens for vaccine development and implementation.

Carriage prevalence of Neisseria meningitidis in China, 2005-2022: a systematic review and meta-analysis

INTRODUCTION

Neisseria meningitidis (Nm) is a major cause of meningitis and septicemia. Most people are infected with latent infections or are carriers. We aimed to estimate the carriage prevalence of Nm in China.

METHODS

We did a systematic review of published work to assess the prevalence of meningococcal carriage in China. The quality assessment was conducted by the risk of bias tool according to Damian Hoy's study. We estimated pooled proportions of carriage and its 95% confidence interval (95% CI) using fixed effect model for studies with low heterogeneity and random effect model for studies with moderate or high heterogeneity. Subgroup analyses were also conducted by region and age group.

RESULTS

In total, 115 studies were included. The quality evaluation grades of all included documents were medium or high grade. The weighted proportion of carriage was 2.86% (95% CI: 2.25-3.47%, I2: 97.7%, p = 0). The carriage prevalence of Nm varied between provinces, ranged from 0.00% (95% CI: 0.00-0.66%) to 15.50% (95% CI: 14.01-16.99%). Persons aged 15 years and older had the highest carriage 4.38% (95% CI: 3.15-5.62%, I2: 95.4%, p < 0.0001), and children under 6 years of age had the lowest carriage 1.01% (95% CI: 0.59-1.43%, I2: 74.4%, p < 0.0001). In positive carriers, serogroup B (41.62%, 95% CI: 35.25-48.00%, I2: 98.6%, p = 0) took up the highest proportion, and serogroup X (0.02%, 95% CI: 0.00-0.09%, I2: 0.00%, p = 1) accounted for the lowest proportion.

CONCLUSION

The meningococcal carriage in China was estimated low and varied by region and age group. Understanding the epidemiology and transmission dynamics of meningococcal infection in insidious spreaders is essential for optimizing the meningococcal immunization strategies of the country.

Serum proteases prevent bacterial biofilm formation: role of kallikrein and plasmin

Biofilm formation is a general strategy for bacterial pathogens to withstand host defense mechanisms. In this study, we found that serum proteases inhibit biofilm formation by Neisseria meningitidis, Neisseria gonorrhoeae, Haemophilus influenzae, and Bordetella pertussis. Confocal laser-scanning microscopy analysis revealed that these proteins reduce the biomass and alter the architecture of meningococcal biofilms. To understand the underlying mechanism, the serum was fractionated through size-exclusion chromatography and anion-exchange chromatography, and the composition of the fractions that retained anti-biofilm activity against N. meningitidis was analyzed by intensity-based absolute quantification mass spectrometry. Among the identified serum proteins, plasma kallikrein (PKLK), FXIIa, and plasmin were found to cleave neisserial heparin-binding antigen and the α-peptide of IgA protease on the meningococcal cell surface, resulting in the release of positively charged polypeptides implicated in biofilm formation by binding extracellular DNA. Further experiments also revealed that plasmin and PKLK inhibited biofilm formation of B. pertussis by cleaving filamentous hemagglutinin. We conclude that the proteolytic activity of serum proteases toward bacterial adhesins involved in biofilm formation could constitute a defense mechanism for the clearance of pathogens.

Geographically widespread invasive meningococcal disease caused by a ciprofloxacin resistant non-groupable strain of the ST-175 clonal complex

INTRODUCTION

Invasive meningococcal disease (IMD) caused by non-serogroupable (NG) strains mainly affects immunocompromised individuals. Reduced susceptibility to penicillin in meningococci is increasing in Europe but ciprofloxacin resistance remains rare. In 2019, three travel-related meningococcal disease cases caused by a ciprofloxacin-resistant NG strain were identified in England, leading Germany to report four additional IMD cases (2016 to 2019). We describe these and newly identified cases and characterise the strain responsible.

METHODS

Cases were identified as part of national surveillance and by analysing available genomes using PubMLST tools.

RESULTS

Of the cases identified in England in 2019, two geographically distinct cases developed conjunctivitis after returning from Mecca (Kingdom of Saudi Arabia) and a third linked case presented with IMD. Of the four cases from Germany, three occurred in asylum seekers - two familial and a further geographically distinct case. Further IMD cases were identified in Italy (n = 2; 2017-2018), Sweden (n = 1; 2016) and England (n = 1; 2015). A single ST-175 clonal complex (cc175) strain with genosubtype P1.22-11,15-25 was responsible. Decreased susceptibility to penicillin was widespread with three ciprofloxacin resistant subclusters. Constituent isolates were potentially covered by subcapsular vaccines.

CONCLUSION

This disease associated NG cc175 strain exhibits resistance to antibiotics commonly used to prevent IMD but is potentially covered by subcapsular (meningococcal B) vaccines.