Clare Nourse

Community-acquired methicillin-resistant Staphylococcus aureus causes severe disseminated infection and deep venous thrombosis in children : Literature review and recommendations for management

Abstract:  Community‐acquired methicillin‐resistant Staphylococcus aureus (CA‐MRSA) infection in children is increasingly common and can be associated with dissemination and life‐threatening complications. Empiric therapy for presumed severe Staphylococcus aureus infection should be reviewed. Four children with severe invasive CA‐MRSA infection causing osteomyelitis and pneumonia complicated by pulmonary embolus and deep venous thrombosis are described. The literature is reviewed and recommendations for management are provided.

Control of a nosocomial outbreak of vancomycin resistant Enterococcus faecium in a paediatric oncology unit: risk factors for colonisation

Abstract In order to determine the extent of vancomycin resistant enterococcus (VRE) colonisation within a paediatric oncology unit, the risk factors for the acquisition of the organism, the molecular epidemiology of the isolates and the impact of infection control measures, extensive patient and environmental surveillance was undertaken with identification, antibiotic susceptibility testing and pulsed-field gel electrophoresis (PFGE) of all VRE isolates. A matched case control study was carried out. Fourteen patients (19% of screened patients) with VRE colonisation were identified (12 with Enterococcus faecium). All isolates manifested the Van A phenotype. Extensive environmental contamination with VRE was present. PFGE of E. faecium isolates from 10 patients and from five of six environmental cultures revealed patterns suggesting genetic relatedness. Following comparison of the 14 cases with 41 controls matched for age (±4 years) and cohabitation on the oncology unit, risk factors for colonisation with VRE included duration of neutropenia, (OR, 3.72; 95% CI, 1.0–13.1), and antibiotic therapy, (OR, 4.07; 95% CI, 1.08–15.3), the number of antibiotic agents received, (OR, 8.4; 95% CI, 1.34–34.3) and the duration of therapy with amikacin, (OR, 10.7; 95% CI, 1.4–81.5), ceftazidime, (OR, 11.5; 95% CI, 2.2–59.9) or teicoplanin, (OR, 12.3; 95% CI, 2.25–67.4). Implementation of stringent infection control measures reduced environmental contamination from 25% of samples in week 1 to none in week 11. Two additional colonised patients were identified during the subsequent 6 months. Conclusion Risk factors for VRE colonization in paediatric oncology patients included duration of neutropenia, duration of any antibiotic therapy, exposure to ceftazidime, amikacin or teicoplanin and the number of antibiotics used. The study suggests that environmental contamination played an important role in patient-to-patient transmission of VRE and interventions including implementation of infection control measures were associated with a decreased incidence of gastro-intestinal colonisation.

Disseminated Varicella Infection Caused by Varicella Vaccine Strain in a Child With Low Invariant Natural Killer T Cells and Diminished CD1d Expression

BACKGROUND Live attenuated varicella vaccine is considered a safe vaccine with serious adverse effects reported only in immunocompromised children. We describe a severe life-threatening infection with varicella vaccine virus causing rash and pneumonitis in a 6-year-old boy with no apparent immunodeficiency. METHODS AND RESULTS Polymerase chain reaction (PCR) analysis of vesicle swab samples demonstrated varicella zoster virus (VZV). Sequencing of the PCR product demonstrated 100% homology with human herpesvirus 3 strain VZV-Oka ORF62 gene. Routine immunologic investigations failed to demonstrate any abnormality. Total leukocyte, lymphocyte, and neutrophil counts and lymphocyte subsets were normal. Immunoglobulins, C3, C4, and CH50 were intact. Specific IgG to protein and polysaccharide antigens and to Epstein-Barr virus and cytomegalovirus were present. Normal lymphocyte proliferation to phytohemagglutinin and VZV antigens was detected. Neutrophil function and natural killer (NK) cell activity were normal. The analysis of invariant NK T (iNKT) cell numbers and function revealed diminished iNKT cells, reported once previously and unique to our patient, deficient expression of the cognate receptor, CD1d. CONCLUSIONS This report provides a further link between deficiency of the iNKT/CD1d pathway and increased susceptibility to varicella vaccine virus, suggesting an important role of this innate pathway in host defense against yet another member of the herpesvirus family.

Three Cases of Q Fever Osteomyelitis in Children and a Review of the Literature

Q fever is a common zoonosis worldwide. Awareness of the disease and newer diagnostic modalities have resulted in increasing recognition of unusual manifestations. We report 3 cases of Q fever osteomyelitis in children and review the literature on 11 other reported cases. The cases demonstrate that Coxiella burnetii can cause granulomatous osteomyelitis that presents without systemic symptoms and frequently results in a chronic, relapsing, multifocal clinical course. Optimal selection and duration of antimicrobial therapy and methods of monitoring therapy are currently uncertain.

Eradication of vancomycin resistant Enterococcus faecium from a paediatric oncology unit and prevalence of colonization in hospitalized and community-based children

We previously reported an outbreak of vancomycin resistant enterococci (VRE) in a paediatric oncology unit in December 1995 which was associated with widespread environmental contamination of the unit with VRE. We undertook this study to evaluate the effectiveness of the infection control policy instituted subsequent to the outbreak and to investigate the underlying prevalence of VRE colonization in hospitalized, outpatient and community-based children. We sought to establish the molecular similarity of VRE isolates from the study. Stool specimens were obtained from outpatients at risk of VRE, hospital inpatients and from healthy community-based children. VRE colonization was eradicated from the inpatient unit within 11 months, but in outpatients, 16 months after the outbreak, 4 of 137 (2.9 %) attending oncology outpatients, 5 of 65 (7.7%) with cystic fibrosis and 1 of 12 (8.3 %) with liver disease were found to be colonized with VRE. The isolates were all Enterococcus faecium, Van A phenotype except one E. casseliflavus of the Van C phenotype. All were unique in SmaI DNA macrorestriction patterns with the exception of two isolates, which were similar to the original outbreak strain and three further isolates of a single strain but which differed from the outbreak strain. Of 315 hospital inpatients, 2.5 % were colonized with VRE of the Van C resistance phenotype but VRE was not detected in 116 healthy, community-based children. We conclude that effective strategies can successfully control spread of VRE but despite a low prevalence of VRE colonization in hospital patients and in community-based children, outbreaks can occur when infection control practices are not optimal. Continued vigilance to detect VRE and limit spread within hospitals is therefore necessary.

Nontuberculous Mycobacterial Infection in Children A Prospective National Study

Background: The epidemiology and management of nontuberculous mycobacterial (NTM) infection in Australian children is unknown. Methods: From July 2004 to June 2007, clinicians identified children with NTM infection as part of a nationwide active surveillance network. Following notification, detailed data were collected. Results: From 192 reports, data were received on 153 cases (response rate: 79.7%). Of these, 102 met inclusion criteria. The median age was 2.9 years. Predisposing conditions were infrequent and included chronic respiratory disease (n = 12) and immunosuppression (n = 6). Lymphadenitis was the most frequent presentation (n = 68) with pulmonary and disseminated disease infrequent (n = 14 and 3, respectively). NTM was isolated in 68 cases with Mycobacterium avium-intracellulare complex most frequently isolated (33/68; 48.5%). Surgery was performed in 78 cases and 42 children were treated with antimycobacterial therapy. Twenty-five subjects received surgery and antimycobacterial therapy. Follow-up data were available for 77 children with recurrence observed in 18 cases. Complete excision was associated with a higher rate of treatment success when compared with all other therapies (OR: 9.48 [95% CI: 2.00–44.97], P = 0.001). Mycobacterium lentiflavum infection accounted for 4.4% of culture confirmed cases and had a lower rate of treatment success than other species (0% vs. 78.2%; P = 0.016). Conclusions: The incidence of NTM infection in Australian children is 0.84 of 100,000 (95% CI: 0.68–1.02). Infection occurs most often in young children without predisposing conditions. Despite therapy, there was recurrence in 23.4% of cases.

First outbreak of PVL-positive nonmultiresistant MRSA in a neonatal ICU in Australia: comparison of MALDI-TOF and SNP-plus-binary gene typing.

The purpose of this brief report is to describe the first outbreak of a community-associated nonmultiresistant and PVL-positive MRSA strain (CC30) in a neonatal intensive care unit in Australia. The utility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) for microbial typing is compared with single nucleotide polymorphism (SNP) plus binary gene analysis. The composite correlation index analysis of the MALDI-TOF-MS data demonstrated the similar inter-strain relatedness found with the SNP-plus-binary gene typing used to confirm the outbreak. The evolving spread of MRSA emphasizes the importance of surveillance, infection control vigilance and the ongoing investigation of rapid typing methods for MRSA.

Australian Bat Lyssavirus in a Child: The First Reported Case

Human infection with Australian Bat Lyssavirus is extremely rare and has not previously been reported in a child. We describe a fatal case of Australian Bat Lyssavirus in an 8-year-old child, and review the literature pertaining to the diagnosis and management of lyssavirus infection with consideration of its applicability to this emerging strain.

Antibiotic duration and timing of the switch from intravenous to oral route for bacterial infections in children: systematic review and guidelines

Few studies are available to inform duration of intravenous antibiotics for children and when it is safe and appropriate to switch to oral antibiotics. We have systematically reviewed antibiotic duration and timing of intravenous to oral switch for 36 paediatric infectious diseases and developed evidence-graded recommendations on the basis of the review, guidelines, and expert consensus. We searched databases and obtained information from references identified and relevant guidelines. All eligible studies were assessed for quality. 4090 articles were identified and 170 studies were included. Evidence relating antibiotic duration to outcomes in children for some infections was supported by meta-analyses or randomised controlled trials; in other infections data were from retrospective series only. Criteria for intravenous to oral switch commonly included defervescence and clinical improvement with or without improvement in laboratory markers. Evidence suggests that intravenous to oral switch can occur earlier than previously recommended for some infections. We have synthesised recommendations for antibiotic duration and intravenous to oral switch to support clinical decision making and prospective research.

Increasing pyomyositis presentations among children in Queensland, Australia.

Background: Pyomyositis, usually associated with tropical climates, occurs less commonly in temperate regions and is most often caused by Staphylococcus aureus. Several community-acquired methicillin-resistant S. aureus (CA-MRSA) clones have emerged in Queensland since the beginning of the century, and they now account for a significant proportion of invasive staphylococcal infection. This study aims to describe trends in the rate of presentation, and the clinical and diagnostic features of pyomyositis, and to determine if trends are attributed to the emergence of CA-MRSA or other factors. Methods: A 10-year retrospective cohort study of all patients presenting to Mater Children’s Hospital in Brisbane, Queensland, with pyomyositis between July 2002 and July 2012, was conducted. Data were collected for clinical features, microbiology, diagnostic tests, management and outcome. Trends in incidence, and clinical and diagnostic features of pyomyositis were analyzed. Results: Thirty-four cases of pyomyositis were identified. There was a male predominance (79%), and the vertebro-pelvic muscles were most often affected. The rate of pyomyositis increased significantly during the study period from a rate of 2.04 cases per 10,000 emergency department admissions in the first quarter of the study, to 8.73 cases per 10,000 in the final quarter (peak rate 13.5 cases per 10,000 in 2008). A causative organism was identified in 22 cases, most commonly methicillin-susceptible S. aureus with CA-MRSA identified in 4 cases. Patients who required surgical intervention had longer hospital admission, longer time to resolution of inflammatory markers and a higher risk of complication at follow-up. Conclusion: This study demonstrates an increasing incidence of pyomyositis in a temperate region, which is not attributable to the emergence of CA-MRSA. The reasons for this change in incidence are not clear.