Bacteremia, meningitis, and brain abscesses in a hospitalized infant: complications of Pseudomonas aeruginosa conjunctivitis

Preterm infants with positive conjunctival swab culture: risk factors and association with late-onset sepsis-a retrospective cohort study

Introduction

Purulent conjunctival discharge in hospitalized preterm infants may indicate conjunctivitis and warrant treatment. The purpose of this study was to examine the relationship between positive conjunctival swab (CS) culture and late-onset sepsis (LOS) in preterm infants.

Methods

A retrospective cohort study was conducted to determine the relationship between positive CS culture growth results (CSP) obtained in preterm infants ≤34 weeks' gestation and the development of LOS within 120 h of obtaining CS compared with those who had negative CS culture results (CSN). Electronic medical records were reviewed from January 2015 until December 2019 for preterm infants presenting with purulent conjunctival discharge and underwent CS culture testing due to suspected conjunctivitis.

Results

Of the 234 CS cultures obtained during the study period, 145 (61.9%) were CSP compared to 89 (38.1%) CSN cultures. Gram-negative organisms accounted for 70% of all CSP cultures, with the remaining 30% being Gram-positive. Patients with CSP were smaller, younger, had lower 1-minute APGAR scores, and required respiratory support more frequently than those with CSN. Infants with CSP received antibiotics for longer periods, both topically and systemically. Infants who developed LOS were more likely to require invasive ventilation (adjusted odds ratio, 33.5; 95% CI, 2.52-446.5, p = 0.008). The incidence of LOS between the two groups was similar, with 6.2% observed in the CSP group compared to 3.4% in the CSN group (p = 0.543). Similarly, the rates of bacteremia were similar in both groups. Of the CSP patients who were presented with bacteremia, four out of seven (57%) exhibited bacteremia caused by the same organism found in their CS cultures. Similarly, within the entire cohort, respiratory cultures were performed on nine intubated patients within two weeks of obtaining CS cultures. Of these, in the CSP group, five out of six (83%) showed an organism identical to that found in the CS cultures.

Conclusion

The study found a significant proportion of positive CS cultures in preterm infants, with distinct patient characteristics and treatment compared to negative cultures. While the incidence of LOS was not significantly different between the two groups, some CSP patients demonstrated bacteremia with the same CS organism, suggesting a possible connection between conjunctival or respiratory colonization and bacteremia.

Repurposing phytochemicals as anti-virulent agents to attenuate quorum sensing-regulated virulence factors and biofilm formation in Pseudomonas aeruginosa

Unregulated consumption and overexploitation of antibiotics have paved the way for emergence of antibiotic‐resistant strains and ‘superbugs’. Pseudomonas aeruginosa is among the opportunistic nosocomial pathogens causing devastating infections in clinical set‐ups globally. Its artillery equipped with diversified virulence elements, extensive antibiotic resistance and biofilms has made it a ‘hard‐to‐treat’ pathogen. The pathogenicity of P. aeruginosa is modulated by an intricate cell density‐dependent mechanism called quorum sensing (QS). The virulence artillery of P. aeruginosa is firmly controlled by QS genes, and their expression drives the aggressiveness of the infection. Attempts to identify and develop novel antimicrobials have seen a sharp rise in the past decade. Among different proposed mechanisms, a novel anti‐virulence approach to target pseudomonal infections by virtue of anti‐QS and anti‐biofilm drugs appears to occupy the centre stage. In this respect, bioactive phytochemicals have gained prominence among the scientific community owing to their significant quorum quenching (QQ) properties. Recent studies have shed light on the QQ activities of various phytochemicals and other drugs in perturbing the QS‐dependent virulence in P. aeruginosa. This review highlights the recent evidences that reinforce the application of plant bioactives for combating pseudomonal infections, their advantages and shortcomings in anti‐virulence therapy.

Conjunctival Goblet Cell Responses to TLR5 Engagement Promote Activation of Local Antigen-Presenting Cells

Conjunctival epithelium forms a barrier between the ocular surface microbial flora and the ocular mucosa. In addition to secreting gel-forming mucins, goblet cells, located in the conjunctival epithelium, help maintain local immune homeostasis by secreting active TGFβ2 and promoting tolerogenic phenotype of dendritic cells in the vicinity. Although dendritic cell subsets, characteristic of mucosal tissues, are found in the conjunctiva, previous studies provided limited information about their location within the tissue. In this study, we examine immunostained conjunctiva explants to determine the location of CD11c-positive dendritic cells in the context of MUC5AC-positive goblet cells. Considering that conjunctival goblet cells are responsive to signaling induced by pathogen recognition receptors, we also assess if their responses to microbial product, flagellin, can contribute to the disruption of ocular mucosal homeostasis that promotes activation of dendritic cells and results in chronic ocular surface inflammation. We find that dendritic cells in the conjunctiva with an increased microbial colonization are located adjacent to goblet cells. While their cell bodies in the stromal layer are immediately below the epithelial layer, several extensions of dendritic cells are projected across the epithelium towards the ocular surface. Such trans-epithelial dendrites are not detectable in healthy ocular mucosa. In response to topically applied flagellin, increased proportion of CD11c-positive cells in the conjunctiva strongly express MHC class II relative to the untreated conjunctiva. This change is accompanied by reduced immunoreactivity to TGFβ-activating Thrombospondin-1 in the conjunctival epithelium. These findings are supported by in vitro observations in primary cultures of goblet cells that respond to the TLR5 stimulation with an increased expression of IL-6 and reduced level of active TGFβ. The observed changes in the conjunctiva after flagellin application correspond with the development of clinical signs of chronic ocular mucosal inflammation including corneal epitheliopathy. Collectively, these findings demonstrate the ability of ocular mucosal dendritic cells to extend trans-epithelial dendrites in response to increased microbial colonization at the ocular surface. Moreover, this study provides key insight into how goblet cell responses to microbial stimuli may contribute to the disruption of ocular mucosal homeostasis and chronic ocular mucosal inflammation.

State-of-the-art polymeric nanoparticles as promising therapeutic tools against human bacterial infections

Infectious diseases kill over 17 million people a year, among which bacterial infections stand out. From all the bacterial infections, tuberculosis, diarrhoea, meningitis, pneumonia, sexual transmission diseases and nosocomial infections are the most severe bacterial infections, which affect millions of people worldwide. Moreover, the indiscriminate use of antibiotic drugs in the last decades has triggered an increasing multiple resistance towards these drugs, which represent a serious global socioeconomic and public health risk. It is estimated that 33,000 and 35,000 people die yearly in Europe and the United States, respectively, as a direct result of antimicrobial resistance. For all these reasons, there is an emerging need to find novel alternatives to overcome these issues and reduced the morbidity and mortality associated to bacterial infectious diseases. In that sense, nanotechnological approaches, especially smart polymeric nanoparticles, has wrought a revolution in this field, providing an innovative therapeutic alternative able to improve the limitations encountered in available treatments and capable to be effective by theirselves. In this review, we examine the current status of most dangerous human infections, together with an in-depth discussion of the role of nanomedicine to overcome the current disadvantages, and specifically the most recent and innovative studies involving polymeric nanoparticles against most common bacterial infections of the human body.

The clinical features and therapy of community-acquired gram negative bacteremia in children less than three years old

BACKGROUND

Community-acquired Gram-Negative (GN) bacteremia caused more morbidity and mortality recently in children. The increasing drug resistance was also an important issue. However, published reference was few about children.

METHODS

We conducted a retrospective study to collect febrile patients with blood culture from a pediatric emergency department during 2007∼2013, and exclude cases ever admitted to hospital within 14 days. These blood cultures all showed single GN organism. The demographic characteristics of enrolled patients and the antibiogram of pathogens were recorded, and then were compared statistically to find out the immediate and appropriate antibiotics.

RESULTS

Total 143 sets of blood culture were GN bacilli and the median age of cases was 2 (IQR, 1-5) years old. Male gender was predominant. Non-fermenting Gram-negative bacilli group (NFGNB spp.), Salmonella spp. and Escherichia coli were first three common pathogens respectively. However, total 37 cases of NFGNB spp. other than Pseudomonas aeruginosa were the possible pathogens. By multiple logistic regression analysis, lower hemoglobin and higher alanine aminotransferase were significant difference between common pathogens and possible ones. Besides, the prevalent age regarding resistant strains of Escherichia coli and Pseudomonas aeruginosa were both focused on less than 1 year old. However, Salmonella spp. were prevalent in the age from 1 to 3 years old.

CONCLUSIONS

For different age groups, Salmonella spp. and Escherchia coli were the most common pathogens of community-acquired GN bacteremia. For infants, Pseudomonas aeruginosa sepsis and resistant strain of Escherchia coli should be alert, and broader antibiotics should be considered.

Blood Microbial Communities During Pregnancy Are Associated With Preterm Birth

Microbial infection of the placenta, amniotic fluid, vaginal canal, and oral cavity is known to significantly contribute to preterm birth (PTB). Although microbes can be translocated into the blood, little is known regarding the blood microbiota during pregnancy. To assess changes in the microbiome during pregnancy, blood samples were obtained 2 or 3 times during pregnancy from a cohort of 45 pregnant women enrolled between 2008 and 2010. To analyze the association with PTB, we conducted a case-control study involving 41 pregnant women upon admission for preterm labor and rupture of membrane (20 with term delivery; 21 with PTB). Bacterial diversity was assessed in number and composition between the first, second, and third trimesters in term delivered women according to 16S rRNA gene amplicon sequencing, and data were analyzed using Quantitative Insight Into Microbial Ecology (QIIME). Taxonomy was assigned using the GreenGenes 8.15.13 database. Dominant microorganisms at the phylum level in all pregnant women were identified as Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. However, the number and composition of bacteria in women with PTB differed from that in women with term delivery. Firmicutes and Bacteroidetes were more abundant in women with PTB than in women with term delivery, while Proteobacteria was less prevalent in women with PTB. At the genus level, Bacteroides, Lactobacillus, Sphingomonas, Fastidiosipila, Weissella, and Butyricicoccus were enriched in PTB samples. These observational results suggest that several taxa in the maternal blood microbiome are associated with PTB. Further studies are needed to confirm the composition of the blood microbiota in women with PTB. Additionally, the mechanism by which pathogenic microbes in maternal blood cause infection and PTB requires further analysis.

Incidence, Etiology and Risk Factors Associated with Neonatal Healthcare-Associated Conjunctivitis: A Prospective Study from a Tertiary Care Hospital in India

INTRODUCTION

Healthcare-associated conjunctivitis (HAC) can lead to serious sequelae including blindness. We conducted a one-year prospective study to determine the epidemiology of neonatal HAC at a tertiary-care hospital in India.

METHODS

From the neonates fulfilling a set of predefined inclusion criteria, cases of HAC were diagnosed based on CDC guidelines. Conjunctival swabs, obtained from neonates with suggestive clinical signs, were processed using standard protocols. Twenty-eight potential risk factors were analyzed.

RESULTS

We detected 24 cases of HAC among 591 enrolled neonates, with Escherichia coli being the most frequently isolated microorganism. On multivariate analysis, intubation at birth (p = 0.046) and orogastric feeding (p = 0.029) had a statistically significant association with neonatal HAC. Average hospitalization increased from 9.6 to 20.8 days for neonates diagnosed with HAC.

CONCLUSION

A standardized case-definition and physician awareness of potential serious sequelae would help improve detection rates and timely institution of therapy. Hand hygiene could help control the menace of neonatal HAC.

Assessment of the relationship between bacteriological quality of dug-wells, hygiene behaviour and well characteristics in two cholera endemic localities in Douala, Cameroon

Background

Access to potable water is grossly inadequate in Douala-Cameroon. The situation is worse in slum areas, compelling inhabitants to obtain water from sources of doubtful quality. This has contributed to frequent outbreaks of water-borne diseases particularly cholera, which results in severe morbidity and mortality. Shallow wells are a major source of water in these areas. We analyzed the influence of some factors on the bacteriological quality of well water in Bepanda and New Bell, cholera endemic localities in Douala to generate data that would serve as basis for strengthening of water and health policies.

Methods

Questionnaires were administered to inhabitants of study sites to appraise their hygiene and sanitation practices, and level of awareness of waterborne diseases. The bacteriological quality of water was determined by investigating bacterial indicators of water quality. Relationship between well characteristics and bacteriological quality of water was determined using χ² test. The Kendall tau_b nonparametric correlation was used to measure the strength of association between well characteristics and bacteriological parameters. Statistics were discussed at 95% confidence level. Antibiotic susceptibility of isolates was investigated by the Kirby-Bauer and broth dilution techniques. Multidrug resistant species were tested for extended β-lactamase production potential.

Results

Inhabitants demonstrated adequate knowledge of waterborne diseases but employed inappropriate method (table salt) for well disinfection. Well construction and location violated guidelines. Indicator bacterial counts greatly exceeded the WHO guidelines. Variation in bacteriologic parameters between sites was not significant (P > 0.05) since well characteristics and hygiene and sanitary practices were similar. Differences in bacteriologic quality with respect to state of well, and presence of molded casing and lid, and height of casing were not significant (P > 0.05). Well distance from sanitary structure negatively correlated with bacteriological characteristics indicating it could be a major contributory factor to poor water quality. Bacteria isolated were predominantly enteric organisms. Ciprofloxacin was the most active agent. Extended β-lactamase producers were detected among Salmonella species, Citrobacter fruendii and E. coli.

Conclusion

Poor well location, construction, and hygiene and sanitary practices were among the factors affecting water quality. There is an urgent need for education of inhabitants on effective water disinfection strategies and for regular monitoring of wells.

[Pseudomonas aeruginosa unilateral endogenous endophthalmitis in a preterm infant: a case report]

Endogenous endophthalmitis is a rare eye disease, affecting vulnerable subjects (such as preterm or older elderly subjects), with reserved visual and sometimes vital prognosis. We present a preterm boy, born at 35 weeks and 2 days gestation, who developed a right eye Pseudomonas aeruginosa endogenous endophthalmitis secondary to a left-foot peripherical catheter-infection-associated bacteremia. He had a first intravenous antibiotic therapy associating third-generation cephalosporin and fluoroquinolone, then Ceftazidime® by intravitreous injection and a subconjunctival injection of betamethasone. Because of the development of vitreoretinal retraction, phacophagia and vitrectomy were performed. We point and discuss the severity of this disease, associated with poor visual and vital prognosis, and the importance of prompt biological diagnosis so that the appropriate intravenous antibiotic therapy is chosen. Treatment is also discussed, especially the interest value of antibiotic intravitreous injection in preterm infants.

Role of neutrophils, MyD88-mediated neutrophil recruitment, and complement in antibody-mediated defense against Pseudomonas aeruginosa keratitis

Purpose. Ulcerative keratitis due to Pseudomonas aeruginosa is a sight-threatening disease leading to loss of vision due to corneal inflammation. A human IgG1 monoclonal antibody (MAb F429) to the alginate capsule significantly reduces pathology and bacterial burdens in the cornea when applied topically starting 8 hours post-infection. The purpose of this study was to determine whether local polymorphonuclear neutrophils (PMN) recruitment and complement were important lipopolysaccharide co-factors in MAb F429-mediated reductions in P. aeruginosa tissue levels and corneal pathology. Methods. MyD88 knock-out mice unable to recruit PMN to tissues, mice depleted of PMNs, or mice depleted of complement component C3 were topically treated with MAb F429 starting 8 hours post-infection and evaluated for bacterial levels and corneal pathology 48 hours after infection with two P. aeruginosa isolates. Results. An inability to recruit PMN or systemic PMN depletion plus topical application of MAb F429 resulted in less pathology in the eye, but bacterial burdens were markedly increased in the cornea, brains, and spleens of these mice, indicative of systemic spread. Intraperitoneal injection of cobra venom factor (CVF) reduced C3 levels in the cornea approximately 40%, which did not change the beneficial effects of MAb F429. Both systemic injection and topical application of CVF reduced local C3 levels >60%, which eliminated MAb-mediated reductions in corneal pathology and bacterial levels. Conclusions. PMN recruitment and complement are both needed for maximal in vivo efficacy of MAb F429 in therapeutically treating P. aeruginosa keratitis, and attempts to reduce pathology by limiting PMN influx could have consequences leading to more extensive local and systemic infection.

Pseudomonas aeruginosa induces interleukin-8 (IL-8) gene expression in human conjunctiva through the recruitment of both RelA and CCAAT/enhancer-binding protein beta to the IL-8 promoter

The purpose of this study was to identify the Pseudomonas aeruginosa-activated signaling pathway leading to interleukin (IL)-8 gene expression and protein synthesis by human conjunctival epithelium. IL-8 protein and mRNA were determined by enzyme-linked immunosorbent assay and reverse transcription-PCR, respectively. Activation of MAPKs and NF-kappaB was analyzed by Western blotting using phosphospecific antibodies. We used transfection with wild-type or mutated IL-8 promoters and cotransfection with transcription factor overexpressing plasmids or small interfering RNAs. Electrophoretic mobility shift assay and chromatin immunoprecipitation (ChIP) were performed for in vitro and in vivo protein-DNA binding studies, respectively. P. aeruginosa increased IL-8 expression at the transcriptional level by phosphorylating CCAAT/enhancer-binding protein beta (C/EBPbeta) via p38MAPK and activating NF-kappaB. The simultaneous involvement of RelA and C/EBPbeta and the integrity of the corresponding consensus sites were required, whereas c-Jun was involved only in basal IL-8 expression. Re-ChIP experiments showed that RelA and C/EBPbeta act together at the IL-8 promoter level upon P. aeruginosa infection. Taken together, our results suggest that P. aeruginosa induces IL-8 promoter expression and protein production in conjunctival epithelial cells by activating RelA and C/EBPbeta and by promoting the cooperative binding of these transcription factors to the IL-8 promoter that in turn activates transcription.

Maternal and neonatal infections and obstetrical outcome in water birth

OBJECTIVES

The goal of our study was to assess the effect of water birth on obstetrical outcome, the maternal and neonatal infection rate in a selected low risk collective.

STUDY DESIGN

In this prospective observational study (1998-2002) 513 women, wished to have a water birth. The study was approved by the local ethical committee, informed consent was obtained. According to the course of delivery, we compared three groups: woman who had a water birth, a normal vaginal delivery after immersion and a normal vaginal delivery without immersion. Outcome measurements were maternal and fetal infection rate, obstetrical outcome parameters and relevant laboratory parameters.

RESULTS

The groups were comparable in terms of demographic and obstetric data. The maternal and neonatal infection rate and laboratory parameters showed no significant difference among the groups. There was no maternal infection related to water birth. There were five water born neonates and three neonates after normal vaginal delivery preceded by immersion with conjunctivitis. Significant differences were observed in obstetrical outcome parameters: less use of analgesia, shorter duration of first and second stage of labor, smaller episiotomy rate in water birth. In contrast no differences were seen in all observed fetal outcome parameters: APGAR score, arterial and venous pH, admission rate to neonatal intensive care unit.

CONCLUSIONS

Water birth is a valuable alternative to traditional delivery. The maternal and fetal infection rate was comparable to traditional deliveries. A careful selection of a low risk collective is essential to minimize potential risks.

Pseudomonas aeruginosa endophthalmitis in a preterm infant

Bacterial endophthalmitis is rare in the neonatal period. It occurs in susceptible individuals such as preterm infants. Pseudomonas aeruginosa, a Gram-negative bacillus, has been identified as the causative organism in more than 75% of invasive neonatal eye infections. The source may be endogenous; secondary to septicemia or exogenous, including reports of nosocomial infections and those infections arising from the birth canal. We report the case of a preterm infant who developed pseudomonas endophthalmitis, septicemia, and meningitis after a corneal abrasion.

The value of a CT-guided fine needle aspirate in infants with lung abscess

OBJECTIVE

To describe the range of pathogens isolated from a lung abscess in infants less than one year of age. To assess the role of direct culture from the abscess.

METHODS

The two index cases were managed in 2002. An institution-based review was conducted of all infants up to one year of age diagnosed with a lung abscess between 1989 and 2002. Data sources were hospital's disease index and Neonatal Intensive Care Unit Audit database using ICD9 and ICD10 diagnostic codes for 'lung abscess'.

RESULTS

Five infants, under the age of one year, were treated for a lung abscess. In the one case where the abscess was left-sided it was associated with a congenital cystic adenomatoid malformation of the lung. Pathogens were isolated following direct culture of the abscess in four cases. In three cases a single pathogen was isolated: pseudomonas aeruginosa, staphylococcus aureus and haemophilus influenzae. In one case a mixture of escherichia coli, streptococcus milleri and an anaerobe, propionibacteria, were cultured. Antibiotic therapy was directed at the identified pathogen(s) in all four cases. There was no mortality or recurrence.

CONCLUSION

Predisposing factors for a lung abscess in infancy include prematurity, assisted ventilation, congenital lung anomaly and aspiration. Given the range of potential pathogens, direct culture by CT-guided fine needle aspiration is recommended to direct appropriate intravenous medical therapy provided the abscess is located peripherally.

Pseudomonas fluorescens as a potential pathogen: adherence to nerve cells

In order to determine the infectious potential of the psychrotrophic bacterium Pseudomonas fluorescens, a species closely related to the opportunistic pathogen P. aeruginosa, we investigated the binding activity of this bacterium on primary cultures of rat neonate cortical neurons and glial cells, adrenal paraneurons and NG108-15 neuroblastoma cells. Incubated at concentrations of 10(6) and 10(8) CFU/mL, P. fluorescens MF37 exhibited a high binding activity on neurons in the same range as that of P. aeruginosa PAO1. A significant, but lower, adherence of P. fluorescens was also detected on glial cells and adrenal paraneurons. In contrast, when P. fluorescens MF37 or P. aeruginosa PAO1 were incubated with neuroblastoma cells, no binding was observed. In neurons, the association of P. fluorescens with the plasma membrane occurred both on neurites and cell body. Leakage of the cytoplasmic content was frequently noted. Studies performed using the fluorescent probe Hoechst 33258 revealed that in 10% of neurons, P. fluorescens induced the appearance of densely stained clusters of DNA that was typical of an early step of apoptosis. In glial cells exposed to P. fluorescens, marked changes in the morphology of the nucleus, including fragmentation into lobular structures and aggregation of DNA, were also reminiscent of the existence of a possible apoptotic mechanism. Taken together, these results reveal that P. fluorescens can bind to nerve cells and affect their physiology and, in agreement with recent clinical observations, suggest that P. fluorescens could behave as a pathogen.

Unusual orbital infections

Because of the confined nature of the orbital space, many disease processes such as cancers, infections, or inflammations present with overlapping clinical manifestations. Also, with the multitude of muscular, neurovascular, sensory, and glandular structures located close to each other in this space, precise anatomic localization of various biologic processes can be difficult. Nevertheless, the aim of this review is to highlight recent publications about unusual orbital infections. The review begins with anatomic and etiologic classification of orbital infectious diseases. It then progresses along an anatomically based scheme to discuss various bacterial and fungal infections. Because of the infrequent occurrence of many of these diseases, emphasis is placed on diagnostic rather than treatment issues. Because of advances in epidemiology, infectious diseases, antibiotic and antifungal pharmacology, and surgical techniques, the majority of orbital infections are relatively benign. This review focuses on those rare and more challenging exceptions.