Detection of Pseudomonas aeruginosa type III antibodies in children with tracheostomies

Aptamer-based biosensors for Pseudomonas aeruginosa detection

Pseudomonas aeruginosa possesses innate antibiotic resistance mechanisms, and carbapenem-resistant Pseudomonas aeruginosa has been considered the number one priority in the 2017 WHO list of antimicrobial-resistant crucial hazards. Early detection of Pseudomonas aeruginosa can circumvent treatment challenges. Various techniques have been developed for the detection of P. aeruginosa detection. Biosensors have recently attracted unprecedented attention in the field of point-of-care diagnostics due to their easy operation, rapid, low cost, high sensitivity, and selectivity. Biosensors can convert the specific interaction between bioreceptors (antibodies, aptamers) and pathogens into optical, electrical, and other signal outputs. Aptamers are novel and promising alternatives to antibodies as biorecognition elements mainly synthesized by systematic evolution of ligands by exponential enrichment and have predictable secondary structures. They have comparable affinity and specificity for binding to their target to antibody recognition. Since 2015, there have been about 2000 journal articles published in the field of aptamer biosensors, of which 30 articles were on the detection of P. aeruginosa. Here, we have focused on outlining the recent progress in the field of aptamer-based biosensors for P. aeruginosa detection based on optical, electrochemical, and piezoelectric signal transduction methods.

Acinetobacter baumannii Is a Risk Factor for Lower Respiratory Tract Infections in Children and Adolescents With a Tracheostomy

BACKGROUND

Lower respiratory tract infections (LRIs) are a major cause of hospitalization for children and adolescents with a tracheostomy. The aim of this study was to identify risk factors for LRI.

METHODS

In this retrospective study, we assessed the number of LRI and hospitalizations for LRI from 2004 to 2014 at the University Hospital Muenster Pediatric Department. We analyzed associations between LRI and clinical findings, and we cultured pathogens in tracheal aspirates (TAs) during noninfection periods. Univariable and multivariable negative, binomial regression analyses were applied to identify associations between possible risk factors and LRI.

RESULTS

Seventy-eight patients had 148 LRI, of which 99 were treated in hospital. The median number of LRI per year was 0.4. Six-hundred thirteen pathogens were detected in 315 specimens; Staphylococcus aureus (22.5%), Pseudomonas aeruginosa (14.8%) and Haemophilus influenzae (6.2%) were most frequently detected. Acinetobacter baumannii is an independent risk factor for LRI (rate ratio, 1.792; P = 0.030) and hospital admissions for LRI (rate ratio, 1.917; P = 0.011).

CONCLUSIONS

Children with a tracheostomy have frequent LRI. A. baumannii but not P. aeruginosa or S. aureus in TA is a risk factor for LRI in children with a long-term tracheostomy. This supports repetitive culture of TA for microbiologic workup to identify children and adolescents with an increased risk for LRI.

Tracheostomy in children: Epidemiology and clinical outcomes

BACKGROUND

Tracheotomy is performed in children for a variety of indications, but can place them at increased risk of lower airway infection with pathogenic organisms. While prior studies have identified Pseudomonas aeruginosa and Staphylococcus aureus as the most common lower airway pathogens in children with tracheostomies, little is known about the clinical implications of chronic growth of pathogens.

METHODS

The North Carolina Children's Airway Center database was utilized to identify all pediatric patients with tracheostomy from 2007 to 2012; these data were cross-referenced to a microbiology database of all tracheostomy cultures. Data on hospitalizations, intensive care unit admissions, and length-of-stay were abstracted from the medical record and analyzed using multivariate methods.

RESULTS

We identified 185 children with tracheostomy, of whom chronic bacterial growth status could be defined in 69. P aeruginosa was a common pathogen isolated from tracheostomy cultures, with 49% (91/185) of patients growing this organism at least once. P aeruginosa combined with other gram-negative rods were isolated in 63% (116/185) of subjects at least once. Those who chronically grew gram-negative rods had significantly more hospitalizations, longer total lengths-of-stay, and longer intensive care unit lengths-of-stay than those who did not. These differences remained significant when data were normalized to account for number of available cultures.

CONCLUSION

These data suggest that clinical outcomes may be worse in children with tracheostomies who chronically grow gram-negative rods. Our findings may help guide clinicians in managing children with tracheostomies, though further studies are needed to establish best practice guidelines in these patients.

Multidrug- and Carbapenem-Resistant Pseudomonas aeruginosa in Children, United States, 1999-2012

BACKGROUND

Pseudomonas aeruginosa is a common cause of healthcare-associated infection. Multidrug-resistant (MDR) (>3 classes) and carbapenem-resistant (CR) P aeruginosa are significant threats globally. We used a large reference-laboratory database to study the epidemiology of P aeruginosa in children in the United States.

METHODS

Antimicrobial susceptibility data from the Surveillance Network were used to phenotypically identify MDR and CR P aeruginosa isolates in children aged 1 to 17 years between January 1999 and July 2012. Logistic regression analysis was used to calculate trends in the prevalence of MDR and CR P aeruginosa. Isolates from infants (<1 year old) and patients with cystic fibrosis were excluded.

RESULTS

Among the isolates tested, the crude proportion of MDR P aeruginosa increased from 15.4% in 1999 to 26% in 2012, and the proportion of CR P aeruginosa increased from 9.4% in 1999 to 20% in 2012. The proportion of both MDR and CR P aeruginosa increased each year by 4% (odds ratio [OR], 1.04 [95% confidence interval (CI), 1.03-1.04] and 1.04 [95% CI, 1.04-1.05], respectively). In multivariable analysis, both MDR and CR P aeruginosa were more common in the intensive care setting, among children aged 13 to 17 years, in respiratory specimens, and in the West North Central region. In addition, resistance to other antibiotic classes (aminoglycosides, fluoroquinolones, cephalosporins, and piperacillin-tazobactam) often used to treat P aeruginosa increased.

CONCLUSIONS

Rates of MDR and CR P aeruginosa infection in children are rising nationally. Aggressive prevention strategies, including instituting antimicrobial stewardship programs in pediatric settings, are essential for combating antimicrobial resistance.

Detection methods for Pseudomonas aeruginosa: history and future perspective

The current review summarized and analyzed the development of detection techniques forPseudomonas aeruginosaover the past 50 years.

Mucosal and systemic antibody responses to potential Pseudomonas aeruginosa vaccine protein antigens in young children with cystic fibrosis following colonization and infection

Pseudomonas aeruginosa is an important prognostic determinant in cystic fibrosis (CF). Little is known however, about P. aeruginosa induced local mucosal and systemic immune responses. Twenty CF children were categorized according to their P. aeruginosa status: (1) chronic lower respiratory tract infection (LRTI), (2) prior successfully treated initial LRTI, (3) isolated upper respiratory tract (URT) colonization, and (4) no known URT colonization or previous LRTI. Their antibody responses, and those of six non-CF disease controls, in serum and bronchoalveolar lavage (BAL) fluid to potential P. aeruginosa vaccine antigens outer membrane protein F (OprF), outer membrane protein H (OprH), catalase A (KatA) and a whole killed cell (WKC) extract were evaluated. Outer membrane protein G (OprG) responses were also measured in blood. Natural exposure, colonization and infection resulted in detectable antibody levels in BAL and serum in all CF groups. Both chronically infected and URT colonized CF children had substantially elevated immunoglobulin A antibody levels in the BAL fluid and sera toward the WKC extract and OprF antigen compared with the other groups of CF children and non-CF controls. The serum levels of specific P. aeruginosa antibodies involving immunoglobulin G and M isotypes increased with chronic LRTI, especially antibody levels to KatA, OprH and WKC extract, which were substantially greater in chronically infected children compared with all other groups. In conclusion, natural exposure, URT colonization and LRTI with P. aeruginosa all induce substantial mucosal and systemic antibody responses to potential vaccine antigens with chronically infected CF children having the highest levels.