Hypervirulent Strains of Neisseria meningitidis and Clinical Manifestations in Children With Invasive Meningococcal Disease

BACKGROUND

Hypervirulent clonal complex (cc) have been associated with higher incidence and case fatality rate of invasive meningococcal disease (IMD). The aim of this study was to describe the clinical manifestations of the hypervirulent cc of meningococcus in children.

METHODS

Retrospective study in patients hospitalized by IMD microbiologically confirmed at three children's tertiary health care centers in Santiago, Chile, between 2010 and 2018. Demographic, clinical information and determination of the cc and factor H binding protein (fHbp) alleles were performed.

RESULTS

In total 93 cases were evaluated, sequence typing was available for 91 cases, and 87 (95.6%) had a cc assigned; 63.7% were MenW and 31.8% MenB. The median age was 9 months, 67% were male and 18.7% had any comorbidity. A 26.4% presented neurological deficit, 25.3% petechiae and 20% diarrhea. Sixty-seven percent were admitted to the pediatric intensive care unit (PICU) and the case fatality rate was 9.9%. Regarding cc and fHbp alleles, ST11, ST41/44 and allele 22 were the most frequently identified, with 63.7%, 19.8% and 72.5%, respectively. We found statistically significant differences between the cc and presence of petechiae, diagnosis of meningococcemia plus meningitis, admission and days in PICU and advanced support. Allele 22 for fHbp was associated with the absence of petechiae, low suspicion of IMD, less diagnosis of meningitis+meningococcemia, PICU admission, advanced support and adrenal insufficiency.

CONCLUSION

Epidemiological and microbiological surveillance of IMD should integrate clinical and laboratory components, including molecular and genetic characterization, to enrich the dynamic understanding of the clinical evolution of IMD.

Deep immunophenotyping reveals biomarkers of MIS-C in a Latin American cohort

Background

Multisystemic inflammatory syndrome in children (MIS-C) is a life-threatening disease that occurs 2-5 weeks after SARS-CoV-2 exposure and is characterized by severe multisystemic inflammation. Early recognition of MIS-C is key to prognosis, therefore establishing clinical and laboratory biomarkers that predict complications is urgently needed.

Objective

To characterize the immune response and clinical features of patients with acute MIS-C and determine biomarkers of disease in a cohort of 42 Latin American patients.

Methods

Immune characterization was performed using flow cytometry from peripheral mononuclear cells and SARS-CoV-2-specific humoral and cellular response was performed using flow cytometry, ELISPOT, ELISA and neutralizing antibody assays.

Results

MIS-C is characterized by robust T cell activation and cytokine storm. We uncovered that while CXCL9, IL-10, CXCL8, CXCL10, IL-6 and IL-18 are significantly elevated in patients with shock, while CCL5 was increased in milder disease. Monocyte dysregulation was specifically associated to Kawasaki-like MIS-C. Interestingly, MIS-C patients show an NK cell degranulation defect that is persistent after 6 months of disease presentation, suggesting it could underlie disease susceptibility. Most MIS-C had gastrointestinal involvement and higher levels of neopterin were identified in their stools, potentially representing a biomarker of intestinal inflammation in MIS-C. SARS-CoV2-specific cellular response and neutralizing antibodies were identifiable in convalescent MIS-C patients suggesting sustained immunity.

Conclusion

Clinical characterization and comprehensive immunophenotyping of Chilean MIS-C cohort provide valuable insights in understanding immune dysregulation in MIS-C and identify relevant biomarkers of disease that could be used to predict severity and organ involvement.

CLINICAL IMPLICATIONS STATEMENT

MIS-C is distinguished by cytokine storm and decreased NK cell degranulation that is persistent after 6 months. Distinct biomarkers were identified for severe and mild forms of disease.

FilmArray® Meningoencephalitis panel in the diagnosis of central nervous system infections: stewardship and cost analysis in a paediatric hospital in Chile

BACKGROUND

Central nervous system (CNS) infection has been an ongoing concern in paediatrics. The FilmArray® Meningoencephalitis (FAME) panel has greater sensitivity in identifying the aetiology of CNS infections. This study's objective was to compare the aetiological identification and hospitalization costs among patients with suspected CNS infection before and after the use of FAME.

METHODS

An analytical observational study was carried out using a retrospective cohort for the pre-intervention (pre-FAME use) period and a prospective cohort for the post-intervention (post-FAME use) period in children with suspected CNS infection.

RESULTS

A total of 409 CSF samples were analysed, 297 pre-intervention and 112 post-intervention. In the pre-intervention period, a total of 85.5% of patients required hospitalization, and in the post-intervention period 92.7% required hospitalization (p < 0.05). Median of ICU days was significantly lower in the post-intervention period than it was in the pre-intervention period. The overall positivity was 9.4 and 26.8%, respectively (p < 0.001). At ages 6 months and below, we found an increase in overall positivity from 2.6 to 28.1%, along with an increased detection of viral agents, S. agalactiae, S. pneumoniae, and N. meningitidis. The use of this diagnostic technology saved between $2916 and $12,240 USD in the cost of ICU bed-days. FAME use provided the opportunity for more accurate aetiological diagnosis of the infections and thus the provision of adequate appropriate treatment.

CONCLUSIONS

The cost/benefit ratio between FAME cost and ICU bed-day cost savings is favourable. Implementation of FAME in Chilean public hospitals saves public resources and improves the accuracy of aetiological diagnosis.

[Panton-Valentine leukocidin toxin associated methicillin-susceptible Staphylococcus aureus infection: a report of two pediatric cases]

Staphylococcus aureus colonizes the nasopharynx in one third of healthy individuals and is also responsible for several infections in pediatrics such as endocarditis, pneumonia and osteoarticular infections. It has several virulence mechanisms, such as Panton Valentine leukocidin (PVL), which is an exotoxin that causes cell death. It is commonly related to methicillin-resistant Staphylococcus aureus (MRSA) and more serious pulmonary and musculoskeletal infections. However, PVL is not exclusive to MRSA. Two clinical cases of patients with infection by methicillin-sensitive Staphylococcus aureus producing this exotoxin are presented.

A prospective, multi-center study of Candida bloodstream infections in Chile

BACKGROUND

Active surveillance is necessary for improving the management and outcome of patients with candidemia. The aim of this study was to describe epidemiologic and clinical features of candidemia in children and adults in tertiary level hospitals in Chile.

METHODS

We conducted a prospective, multicenter, laboratory-based survey study of candidemia in 26 tertiary care hospitals in Chile, from January 2013 to October 2017.

RESULTS

A total of 780 episodes of candidemia were included, with a median incidence of 0.47/1,000 admissions. Demographic, clinical and microbiological information of 384 cases of candidemia, from 18 hospitals (7,416 beds), was included in this report. One hundred and thirty-four episodes (35%) occurred in pediatric patients and 250 (65%) in adult population. Candida albicans (39%), Candida parapsilosis (30%) and Candida glabrata (10%) were the leading species, with a significant difference in the distribution of species between ages. The use of central venous catheter and antibiotics were the most frequent risk factors in all age groups (> 70%). Three hundred and fifteen strains were studied for antifungal susceptibility; 21 strains (6.6%) were resistant to fluconazole, itraconazole, voriconazole, anidulafungin or micafungin. The most commonly used antifungal therapies were fluconazole (39%) and echinocandins (36%). The overall 30-day survival was 74.2%, significantly higher in infants (82%) and children (86%) compared with neonates (72%), adults (71%) and elderly (70%).

CONCLUSIONS

Our prospective, multicenter surveillance study showed a low incidence of candidemia in Chile, with high 30-day survival, a large proportion of elderly patients, C. glabrata as the third most commonly identified strain, a 6.6% resistance to antifungal agents and a frequent use of echinocandins.

Potential effectiveness of copper surfaces in reducing health care-associated infection rates in a pediatric intensive and intermediate care unit: A nonrandomized controlled trial

BACKGROUND

Studies have consistently shown that copper alloyed surfaces decrease the burden of microorganisms in health care environments. This study assessed whether copper alloy surfaces decreased hospital-associated infections in pediatric intensive and intermediate care units.

METHODS

Admitted infants were assigned sequentially to a room furnished with or without a limited number of copper alloyed surfaces. Clinical and exposure to intervention data were collected on a daily basis. To avoid counting infections present prior to admission, patients who stayed in the hospital <72 hours were excluded from analysis. Health care-associated infections (HAIs) were confirmed according to protocol definitions.

RESULTS

Clinical outcomes from 515 patients were considered in our analysis: 261 patients from the intervention arm of the study, and 254 from the control arm. Crude analysis showed an HAI rate of 10.6 versus 13.0 per 1,000 patient days for copper- and non-copper-exposed patients, respectively, for a crude relative risk reduction (RRR) of 0.19 (90% confidence interval, 0.46 to -0.22). Conducting clinical trials to assess interventions that may impact HAI rates is very challenging. The results here contribute to our understanding and ability to estimate the effect size that copper alloy surfaces have on HAI acquisition.

CONCLUSIONS

Exposure of pediatric patients to copper-surfaced objects in the closed environment of the intensive care unit resulted in decreased HAI rates when compared with noncopper exposure; however, the RRR was not statistically significant. The clinical effect size warrants further consideration of this intervention as a component of a systems-based approach to control HAIs.

[Aspergillus fumigatus mediastinitis in an immunocompetent pediatric patient after heart surgery]

Postsurgical aspergillosis occurs primarily in immunocompetent patients whose main predisposing factor is the loss of skin and mucosal integrity during surgery. Local infection tends to be destructive and refractory to treatment and relapses are common. It is important to consider aspergillosis in the differential diagnosis of slowly progressive and destructive surgical site infections with negative bacterial cultures. We present the case of a child who developed Aspergillus fumigatus mediastinitis months after heart surgery.

Copper surfaces are associated with significantly lower concentrations of bacteria on selected surfaces within a pediatric intensive care unit

BACKGROUND

Health care-associated infections result in significant patient morbidity and mortality. Although cleaning can remove pathogens present on hospital surfaces, those surfaces may be inadequately cleaned or recontaminated within minutes. Because of copper's inherent and continuous antimicrobial properties, copper surfaces offer a solution to complement cleaning. The objective of this study was to quantitatively assess the bacterial microbial burden coincident with an assessment of the ability of antimicrobial copper to limit the microbial burden associated with 3 surfaces in a pediatric intensive care unit.

METHODS

A pragmatic trial was conducted enrolling 1,012 patients from 2 high acuity care units within a 249-bed tertiary care pediatric hospital over 12 months. The microbial burden was determined from 3 frequently encountered surfaces, regardless of room occupancy, twice monthly, from 16 rooms, 8 outfitted normally and 8 outfitted with antimicrobial copper.

RESULTS

Copper surfaces were found to be equivalently antimicrobial in pediatric settings to activities reported for adult medical intensive care units. The log10 reduction to the microbial burden from antimicrobial copper surfaced bed rails was 1.996 (99%). Surprisingly, introduction of copper objects to 8 study rooms was found to suppress the microbial burden recovered from objects assessed in control rooms by log10 of 1.863 (73%).

CONCLUSION

Copper surfaces warrant serious consideration when contemplating the introduction of no-touch disinfection technologies for reducing burden to limit acquisition of HAIs.

Novel nonsense mutation in the katA gene of a catalase-negative Staphylococcus aureus strain

We report the first description of a rare catalase-negative strain of Staphylococcus aureus in Chile. This new variant was isolated from blood and synovial tissue samples of a pediatric patient. Sequencing analysis revealed that this catalase-negative strain is related to ST10 strain, which has earlier been described in relation to S. aureus carriers. Interestingly, sequence analysis of the catalase gene katA revealed presence of a novel nonsense mutation that causes premature translational truncation of the C-terminus of the enzyme leading to a loss of 222 amino acids. Our study suggests that loss of catalase activity in this rare catalase-negative Chilean strain is due to this novel nonsense mutation in the katA gene, which truncates the enzyme to just 283 amino acids.

[Risk factor of intestinal colonization with vancomycin resistant Enterococcus spp in hospitalized pediatric patients with oncological disease]

BACKGROUND

The isolation of vancomycin-resistant Enterococcus spp (ERV) has increased significantly within the last few years, along with the risk of infection and dissemination of these bacteria. Our aim was to determine risk factors (RF) for intestinal colonization in hospitalized pediatric patients with oncological disease at Hospital de Niños Roberto del Río.

METHODS

Between January 2012 and December 2013 a transversal study was performed with 107 rectal swabs and processed with a PCR for ERV. The patients were classified as "colonized with ERV" and "not colonized with ERV" and we evaluated possible RF for intestinal colonization in both groups.

RESULTS

VRE colonization was found in 51 patients (52%). The median of time elapsed between oncological diagnosis and VRE colonization was 35 days. The significant RF associated with VRE colonization were days of hospitalization prior to study, neutropenia and treatment with antibiotics within 30 days prior to study and mucositis.

CONCLUSIONS

According to the RF revealed in this study we may suggest prevention standards to avoid ERV colonization. This is the first investigation in our country in hospitalized pediatric patients with oncological disease and processed with a multiplex PCR for ERV, therefore it is a great contribution about this subject in Chile.

Rapid diagnosis of diarrhea caused by Shigella sonnei using dipsticks; comparison of rectal swabs, direct stool and stool culture

Background

We evaluated a dipstick test for rapid detection of Shigella sonnei on bacterial colonies, directly on stools and from rectal swabs because in actual field situations, most pathologic specimens for diagnosis correspond to stool samples or rectal swabs.

Methodology/Principal Findings

The test is based on the detection of S. sonnei lipopolysaccharide (LPS) O-side chains using phase I-specific monoclonal antibodies coupled to gold particles, and displayed on a one-step immunochromatographic dipstick. A concentration as low as 5 ng/ml of LPS was detected in distilled water and in reconstituted stools in 6 minutes. This is the optimal time for lecture to avoid errors of interpretation. In distilled water and in reconstituted stools, an unequivocal positive reaction was obtained with 4 x 10⁶ CFU/ml of S. sonnei. The specificity was 100% when tested with a battery of Shigella and different unrelated strains. When tested on 342 rectal swabs in Chile, specificity (281/295) was 95.3% (95% CI: 92.9% - 97.7%) and sensitivity (47/47) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 95.5 % of cases (328/342) in comparative studies. Positive and negative predictive values were 77% (95% CI: 65% - 86.5%) and 100% respectively. When tested on 219 stools in Chile, Vietnam, India and France, specificity (190/198) was 96% (95% CI 92%–98%) and sensitivity (21/21) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 96.3 % of cases (211/219) in comparative studies. Positive and negative predictive values were 72.4% (95% CI 56.1%–88.6%) and 100 %, respectively.

Conclusion

This one-step dipstick test performed well for diagnosis of S. sonnei both on stools and on rectal swabs. These data confirm a preliminary study done in Chile.