Time to positivity of blood cultures in paediatric patients

AIM

Continuous monitoring of blood culture (BC) systems allows rapid detection of microbial growth. We aimed to determine differences in time to positivity (TTP) in BACTEC BC between organisms and whether a 36-h period was sufficient to detect all relevant pathogenic bacteria for children admitted to a tertiary care paediatric hospital.

METHODS

This was a retrospective audit of positive aerobic (AE) and anaerobic (AN) BC from paediatric inpatients with available TTP from 1 August 2016 to 2 January 2019. First positive BC per bacteraemia episode was analysed.

RESULTS

Overall, 649 BC were positive, of which 480 first positive BC were analysed: 246 AE (51.3%) only, 216 paired (45%) (108 AE and 108 AN) and 18 AN (3.8%) only. There were 372 episodes of bacteraemia in 340 patients. Median age was 19 months (interquartile range (IQR): 1.25-60). Median TTP for AE and AN cultures was 13.20 (IQR: 9.84-18.48) and 13.92 h (IQR: 10.32-17.04), respectively. Organisms were GNR 49.7%, GPC 29.6%, contaminants 14.5%, mixed 3.0%, other 2.4% and yeast 0.8%. Streptococcus agalactiae had the fastest median TTP in AE and AN cultures, followed by Escherichia coli (AE 8.88 vs. 10.20 h). For paired AE and AN cultures, TTP was faster for AE versus AN cultures (13.36 vs. 14.52 h, P = 0.001). A 36-h cut-off time captured 97.7% AE BC and 99.1% AN BC with pathogens, and 86.5% AE BC and 91.7% AN BC with contaminants, respectively.

CONCLUSIONS

GNR were the commonest pathogens in paediatric BC and faster growth was detected in AE versus AN cultures. By 36 h, >97.7% of BC were positive for pathogens versus 86.5% for contaminants.

A phase I/II study of adoptive SARS-CoV-2-specific T cells in immunocompromised hosts with or at risk of severe COVID-19 infection

BACKGROUND

Post-transplant or hematological cancer patients have a higher risk of mortality after infection with ancestral and early variants of severe acute respiratory syndrome (SARS)-CoV-2. Adoptive cell therapy (ACT) with virus-specific T cells (VSTs) could augment endogenous T cell immunity to avoid disease deterioration before viral clearance.

METHODS

We established a third-party SARS-CoV-2-specific T cell (COVID-T) bank in 2020 (NCT04351659) using convalescent and/or vaccinated donors. In a phase I/II study (NCT04457726), 13 adult and pediatric patients, acutely positive for SARS-CoV-2 and predicted to have a high chance of mortality, were recruited from September 2021 to February 2022. Twelve patients received a single dose of COVID-T cells, matched on at least 1 HLA.

RESULTS

A dose of either 75,000 or 150,000 IFN-γ+CD3+ cells/m2 SARS-COV-2-specific T cells did not cause cytokine release syndrome, acute respiratory distress syndrome, or graft-versus-host disease. In the 8 patients who had detectable donor SARS-COV-2-specific T cells after ACT, none progressed to severe disease or died with COVID-19. In contrast, among the other four patients without evidence of donor micro-chimerism, two died of COVID-19.

CONCLUSIONS

Long-acting third-party VSTs from convalescent or vaccinated donors could be expediently produced and might be clinically useful in future pandemics, particularly before global vaccination is implemented.

Investigating urinary characteristics and optimal urine white blood cell threshold in paediatric urinary tract infection: A prospective observational study

Introduction

While the definitive diagnosis of urinary tract infection (UTI) requires a positive urine culture, the likelihood of UTI can be determined by urinalysis that includes white blood cell (WBC) count. We aimed to determine the optimal urine WBC threshold in urinalysis to predict UTIs in children presenting at the emergency department (ED).

Method

We performed a prospective observational study in the ED at KK Women's and Children's Hospital for children below 18 years old who underwent both urine microscopy and urine cultures, between 10 January and 7 November 2022. We assessed the various urine WBC thresholds associated with culture-proven UTIs using sensitivity, specificity, positive and negative predictive values, positive and negative likelihood ratios, and area under receiver operating characteristic curve.

Results

We found a culture-proven UTI rate of 460/1188 (38.7%) among all patients analysed, and 278/998 (27.9%) among those with nitrite-negative urine samples. Among all patients, a urinalysis WBC threshold of 100/μL had a sensitivity of 82.2% (95% confidence interval [CI] 78.4-85.5) and negative predictive value of 86.2% (95% CI 83.6-88.4). Among those who were nitrite-negative, a WBC threshold of ≥100/μL resulted in a potential missed rate of 48/278 (17.3%). By lowering the WBC threshold to ≥10/μL, the potential missed cases reduced to 6/278 (2.2%), with an estimated increase in 419 urine cultures annually.

Conclusion

A urine microscopy WBC threshold of ≥100/μL results in a clinically significant number of missed UTIs. Implementation of various thresholds should consider both the potential missed UTI rate and the required resource utilisation.

Sequence Types and Antimicrobial Resistance Profiles of Salmonella Typhimurium in the Food Chain in Singapore

Salmonella remains a significant foodborne pathogen globally with S. Typhimurium presenting as a frequently occurring serovar. This study aimed to characterize 67 S. Typhimurium isolates from humans, food, farms, and slaughterhouses collected in Singapore from 2016 to 2017. Using whole-genome sequencing analysis, the isolates were found to belong to either ST19 (n = 33) or ST36 (n = 34). ST36 predominated in human intestinal and chicken isolates, while human extra-intestinal and non-chicken food isolates belonged to ST19. Plasmids were predicted in 88.1% (n = 59) of the isolates with the most common incompatibility group profiles being IncFIB(S), IncFII(S) and IncQ1. IncFIB(S) (adjusted p-value < 0.05) and IncFII(S) (adjusted p-value < 0.05) were significantly more prevalent in ST19 isolates, while Col156 (adjusted p-value < 0.05) was more significantly found in ST36 isolates. ST36 isolates exhibited higher resistance to multiple antibiotic classes such as penicillins, phenicols, folate pathway inhibitors, aminoglycosides, β-lactam/β-lactamase inhibitor combinations, tetracyclines, and fluoroquinolones. Phylogenetics analysis suggested potential shared routes of transmission among human, chicken, farm and slaughterhouse environments. Taken together, this study offers a cross-sectional epidemiological insight into the genomic epidemiology and antimicrobial landscape of S. Typhimurium isolates in Singapore, informing strategies for future public health and food safety surveillance.

Viewpoint: The impending pandemic of resistant organisms - a paradigm shift towards source control is needed

The United States needs a paradigm shift in its approach to control infectious diseases. Current recommendations are often made in a siloed feedback loop. This may be the driver for such actions as the abandonment of contact precautions in some settings, the allowance of nursing home residents who are carriers of known pathogens to mingle with others in their facility, and the determination of an intervention's feasibility based upon budgetary rather than health considerations for patients and staff. Data from both the U.S. Veterans Health Administration and the U.K.'s National Health Service support the importance of carrier identification and source control. Both organizations observed marked decreases in methicillin-resistant Staphylococcus aureus (MRSA), but not methicillin-susceptible Staphylococcus aureus infections with the implementation of MRSA admission screening measures. Facilities are becoming over-reliant on horizontal prevention strategies, such as hand hygiene and chlorhexidine bathing. Hand hygiene is an essential practice, but the goal should be to minimize the risk of workers' hands becoming contaminated with defined pathogens, and there are conflicting data on the efficacy of chlorhexidine bathing in non-ICU settings. Preemptive identification of dedicated pathogens and effective source control are needed. We propose that the Centers for Disease Control and Prevention should gather and publicly report the community incidence of dedicated pathogens. This will enable proactive rather than reactive strategies. In the future, determination of a patient's microbiome may become standard, but until then we propose that we should have knowledge of the main pathogens that they are carrying.

Advanced portable micro-SORS prototype coupled with SERDS for heritage science

We investigate the subsurface composition of turbid materials at the micro scale by means of a portable non-invasive technique, micro-spatially offset Raman spectroscopy (micro-SORS), combined with shifted excitation Raman difference spectroscopy (SERDS). This combination enables the microscale layer analysis and allows to deal effectively with highly fluorescing samples as well as ambient light, all in a form of an in-house portable prototype device optimised for applications in heritage science. The instrument comprises ability to simultaneously collect multiple spectra by means of an optical fibre bundle, thus reducing the dead time and simplifying the ease of deployment of the technique. The performance of the synergy between micro-SORS and 785 nm SERDS dual-wavelength diode laser is demonstrated on a stratified mock-up painting samples including highly fluorescing painted layers. This instrumental approach could be ground-breaking in heritage science, due to the largely unmet need of analysing the molecular composition of subsurface of artworks non-invasively and in situ, and in the presence of fluorescent background and ambient light. Moreover, many other fields are expected to benefit from this technological advancement such as solar energy, forensic and food analytical areas.

Outcomes of a targeted congenital cytomegalovirus infection screening approach among infants born ≥35 weeks gestation

Cytomegalovirus (CMV) is a common cause of congenital viral infection. The estimated incidence of congenital CMV (CCMV) is about 1–6% worldwide, although reliable estimates from Singapore and surrounding countries are unavailable.1,2 Previous local serologic studies among pregnant women reported high rates of CMV seropositivity (>80%),3 highlighting the possible high burden of CCMV. With the establishment of oral valganciclovir as an effective treatment for infants with CCMV, prompt diagnosis and treatment of infants with symptomatic disease is important to reduce the risk of moderate to severe sensorineural hearing loss (SNHL) and neurodevelopmental impairment.4 We report the findings of a targeted CCMV screening approach using failed newborn hearing screen (NHS) or small-for-gestational-age (SGA) status as triggers for screening among infants born ≥35 weeks gestation.

Frontline Worker Safety in the Age of COVID-19: A Global Perspective

The third annual Health Watch USA sm webinar conference assembled 16 speakers from 4 continents who shared information regarding frontline worker safety in the age of COVID-19. The U.S. Bureau of Labor Statistics reported a nearly 4000% increase in workplace illness in 2020 compared with 2019. It is estimated that 2% of the U.S. workforce is not working because of long COVID. In addition, the impact is growing with each surge. After the acute illness, patients are often described as recovered, when in fact many have only survived and are coping with the multisystem impacts of long COVID. Long COVID, including its late cognitive, cardiovascular, embolic, and diabetic complications, disproportionately impacts frontline workers, many of whom are of lower socioeconomic status and represented by ethnic minorities. Natural infection and current vaccines do not provide durable protection for reinfection. Herd immunity is not possible at this time. Although SARS-CoV-2 is unlikely to be eliminated, decreasing spread is imperative to slow the rate of mutations, decrease the number of reinfections, and lower the chances of developing long COVID. The primary mode of spread is through aerosolization. Both routine breathing and talking aerosolizes the virus. With the extremely high infectivity of SARS-CoV-2, it is unlikely that central building ventilation alone will be enough to satisfactorily mitigate spread. Additional safe active air cleaning technology, such as upper-room germicidal UV-C lighting, needs to be deployed. Misinformation and disinformation have inhibited response effectiveness. Examples include downplaying the benefit of well-fitted masks and the risks that COVID-19 and long COVID pose to children, along with believing children cannot spread the disease. The engagement of local community leaders is essential to educate the community and drive social change to accept vaccinations and other public health interventions. Vaccinations and natural immunity alone are unlikely to adequately prevent community spread and do not provide durable protection against the risk of long COVID. Frontline workers must keep their immunity as high as possible and work in settings with clean air, along with wearing N95 masks when they are in contact with the public. Finally, there needs to be a financial safety net for frontline workers and their families in the event of incapacitation or death from COVID-19.

Paediatric actinomycosis: A 16-year, single-institution retrospective review of cases

AIM

Actinomycosis is a rare subacute to chronic granulomatous infection which can mimic other infectious or malignant diseases. This study examined the epidemiology and treatment outcome of actinomycosis in children.

METHODS

A retrospective study on children admitted for actinomycosis in a tertiary paediatric hospital in Singapore, from January 2004 to December 2020. Clinical profile, therapeutic interventions and outcomes were examined.

RESULTS

A total of 10 patients were identified; 7 were female. The median age at first presentation was 9.8 years (range 4.7-15.7). The most common presenting symptom was fever (n = 6, 60%), followed by facial or neck swelling (n = 3, 30%) and ear pain (n = 3, 30%). Actinomycosis occurred predominantly in the orocervicofacial region (n = 6, 60%). Four patients (40%) had preceding dental infections in the form of dental caries or gingivitis. One patient had poorly controlled insulin-dependent diabetes mellitus. Actinomycosis was confirmed via culture in four patients, histopathology in four patients and both methods in two patients. All except one patient (n = 9, 90%) underwent surgical procedures. All patients received ampicillin or amoxicillin/clavulanate or other beta-lactams, for a median duration of 6.5 months (range 1.5-14). Complications included osteomyelitis (n = 4, 40%), mastoiditis (n = 2, 20%), brain abscess (n = 1, 10%) and recurrent neck abscess (n = 1, 10%). There was no mortality and all patients achieved complete resolution.

CONCLUSIONS

Paediatric actinomycosis was rare in our 16-year review, but had a high complication rate. It can occur in immunocompetent patients, and dental infection was the predominant risk factor identified. Prognosis was excellent after surgical intervention and appropriate antimicrobial therapy.

SARS-CoV-2 antigen rapid tests and universal screening for COVID-19 Omicron variant among hospitalized children

BACKGROUND

Clinical utility of universal antigen rapid test (ART) in the pediatric setting is unknown. We aimed to assess the performance and utility of universal ART in hospitalized children (≥5-year-old) to prevent nosocomial COVID-19 transmission.

METHODS

Cross-sectional study involving all hospitalized pediatric patients aged ≥5-year-old from 2 periods during Omicron wave. Clinical data, ART and polymerase chain reaction test results were collected.

RESULTS

A total of 444 patients were included from the 2 study periods, and 416 patients (93.7%) had concordant results between ART and polymerase chain reaction. The overall sensitivity and specificity of ART were 83.3% (95% CI: 75.2-89.3) and 97.5% (95% CI: 95.0-98.8), respectively. Negative predictive values of ART between the Omicron emergence and Omicron peak periods for a probable case group were 71.4% and 66.7%, respectively, and for a suspect case group 91.4% and 75.0%, respectively. Negative predictive values for an unlikely case group was >95% in both periods. Positive predictive value of ART was >85% for probable and suspect case groups in both periods. Seventy-five percent of patients (n = 15) who were incorrectly classified as SARS-CoV-2 negative by ART had potentially viable virus. No large nosocomial transmission clusters were detected.

CONCLUSIONS

Universal ART screening may limit nosocomial outbreaks in hospitalized children. The performance can be optimized by considering clinical symptoms, exposure and periods within COVID waves.

Air quality, meteorological variability and pediatric respiratory syncytial virus infections in Singapore

Respiratory syncytial virus (RSV) is an important cause of respiratory illness among children. While studies have focused on the air-quality and climate dependence of RSV infections, few have been undertaken in South-East Asia where the burden of respiratory illness is among the highest across the globe. This study aimed to determine the relationships between climatic factors and air quality with RSV infections among children in Singapore. We obtained all laboratory-confirmed reports of RSV infections in children below 5 years old from the largest public hospital specializing in pediatric healthcare in Singapore. We assessed the independent cumulative effects of air quality and meteorological factors on RSV infection risk using the Distributed Lag Non-Linear Model (DLNM) framework in negative binomial models adjusted for long-term trend, seasonality and changes in the diagnostic systems. We included 15,715 laboratory-confirmed RSV reports from 2009 to 2019. Daily maximum temperature exhibited a complex, non-linear association with RSV infections. Absolute humidity (Relative Risk, 90th percentile [RR_{90th percentile}]: 1.170, 95% CI: [1.102, 1.242]) was positively associated with RSV risk. Higher levels of particulate matter of aerodynamic diameter of less than (i) 2.5 µm (PM_2.5), (ii) 10 µm (PM₁₀), carbon monoxide (CO) and sulfur dioxide (SO₂) were associated with lower RSV infection risk. RSV infections exhibited both annual and within-year seasonality. Our findings suggest that falls in ambient temperature and rises in absolute humidity exacerbated pediatric RSV infection risk while increases in air pollutant concentrations were associated with lowered infection risk. These meteorological factors, together with the predictable seasonality of RSV infections, can inform the timing of mitigation measures aimed at reducing transmission.

The influence of air quality and meteorological variations on influenza A and B virus infections in a paediatric population in Singapore

INTRODUCTION

Influenza is an important cause of paediatric illness across the globe. However, information about the relationships between air pollution, meteorological variability and paediatric influenza A and B infections in tropical settings is limited.

METHODS

We analysed all daily reports of influenza A and B infections in children <5 years old obtained from the largest specialist women and children's hospital in Singapore. In separate negative binomial regression models, we assessed the dependence of paediatric influenza A and B infections on air quality and meteorological variability, using multivariable fractional polynomial modelling and adjusting for time-varying confounders.

RESULTS

Approximately 80% of 7329 laboratory-confirmed reports were caused by influenza A. We observed positive associations between sulphur dioxide (SO₂) exposure and the subsequent risk of infection with both influenza types. We observed evidence of a harvesting effect of SO₂ on Influenza A but not Influenza B. Ambient temperature was associated with a decline in influenza A reports (Relative Risk at lag 5 [RR_lag5]: 0.949, 95% CI: 0.916-0.983). Rainfall was positively associated with a subsequent increase in influenza A reports (RR_lag3: 1.044, 95% CI: 1.017-1.071). Nitrogen dioxide (NO₂) concentration was positively associated with influenza B reports (RR_lag5: 1.015, 95% CI: 1.005-1.025). There was a non-linear association between CO and influenza B reports. Absolute humidity increased the ensuing risk of influenza B (RR_lag5: 4.799, 95% CI: 2.277-10.118). Influenza A and B infections displayed dissimilar but predictable within-year seasonal patterns.

CONCLUSIONS

We observed different independent associations between air quality and meteorological variability with paediatric influenza A and B infections. Anticipated seasonal infection peaks and variations in air quality and meteorological parameters can inform the timing of community measures aimed at reducing influenza infection risk.

Effectiveness of maternal pertussis vaccination in Singapore: A test-negative case-control study

Pertussis vaccination (Tdap -Tetanus-diphtheria-acellular pertussis) for pregnant women has been recommended since November 2017 in Singapore. In this prospective test-negative case-control study from 2018 to 2019, we aimed to evaluate vaccine effectiveness (VE) against pertussis infection and pertussis-related intensive care unit (ICU) admission according to Tdap (Tetanus-diphtheria-acellular pertussis) during pregnancy and/or infant pertussis vaccination. A total of 58 children (26 cases, 32 controls) were recruited with 4 ICU admissions. The median age was 3 months (interquartile range [IQR] 1.50-4.56 months). Overall, 25.9 % of mothers had received antenatal Tdap vaccination and 43.1 % of infants received pertussis vaccination, majority only 1 dose. Tdap in pregnancy alone without infant vaccine or with 0-1 infant dose had a VE of 97.62 % (95 % confidence interval [CI] 53.25-99.88 %), 98.17 % (95 %CI 66.61-99.9 %) respectively, against pertussis infection and 71.9 % (95 %CI 0.0-98.64), 75.86 % (95 % CI 0.0-98.78) respectively, against ICU admissions. Conclusion: Maternal Tdap vaccination was highly protective against infant pertussis and should be routinely recommended for all pregnant women.

Clonal serotype 1c multidrug-resistant Shigella flexneri detected in multiple institutions by sentinel-site sequencing

Shigella flexneri is a major diarrhoeal pathogen, and the emergence of multidrug-resistant S. flexneri is of public health concern. We report the detection of a clonal cluster of multidrug-resistant serotype 1c (7a) S. flexneri in Singapore in April 2022. Long-read whole-genome sequence analysis found five S. flexneri isolates to be clonal and harboring the extended-spectrum β-lactamases bla_CTX−M−15 and bla_TEM−1. The isolates were phenotypically resistant to ceftriaxone and had intermediate susceptibility to ciprofloxacin. The S. flexneri clonal cluster was first detected in a tertiary hospital diagnostic laboratory (sentinel-site), to which the S. flexneri isolates were sent from other hospitals for routine serogrouping. Long-read whole-genome sequence analysis was performed in the sentinel-site near real-time in view of the unusually high number of S. flexneri isolates received within a short time frame. This study demonstrates that near real-time sentinel-site sequence-based surveillance of convenience samples can detect possible clonal outbreak clusters and may provide alerts useful for public health mitigations at the earliest possible opportunity.

Clinical profile of children with parechovirus meningitis in Singapore

Human parechovirus (HPeV) is one of the most common causes of aseptic meningitis in children worldwide. This study aims to review the epidemiology, clinical presentation, and cerebrospinal fluid (CSF) findings in HPeV meningitis and compare these with Enterovirus (EV) meningitis. This is a retrospective study of children aged ≤ 1 year admitted for HPeV meningitis between November 2015 and July 2017, with positive CSF HPeV PCR and negative blood and CSF bacterial cultures. The clinical findings were compared with a historical cohort of children with EV meningitis admitted between July 2008 and July 2011. There were 71 children with HPeV meningitis, aged between 2 and 127 days, with the majority (96%) being ≤ 90 days old. The most common symptoms reported were poor feeding (42%), tachycardia out of proportion to fever (27%), and lethargy (20%). Only 2 patients (3%) had CSF pleocytosis. Cerebral spinal fluid white blood cell counts ranged from 0 to 28 cells/mm³, with a median of 3 cells/mm³ [interquartile range (IQR) 1-6 cells/mm³]. When compared to our historical cohort of EV meningitis ≤ 90 days old, children with HPeV meningitis ≤ 90 days old were less likely to have CSF pleocytosis (OR 0.008, 95% CI 0.001-0.057). HPeV and EV meningitis are known to cause sepsis-like illness in infants < 90 days old. This study further supports this, with the requirement for fluid bolus therapy for tachycardia or poor perfusion noted to be higher in children with HPeV meningitis ≤ 90 days old (OR 6.3, 95% CI 2.7-14.2).

Hearing and Neurodevelopmental Outcomes of Young Infants with Parechovirus-A and Enterovirus Meningitis: Cohort Study in Singapore Children and Literature Review

Parechovirus-A (PeV-A) and Enterovirus (EV) commonly cause childhood aseptic meningitis. Bacterial meningitis in children has been associated with devastating long-term sequelae. However, developmental outcomes are unclear in Parechovirus meningitis. This study aims to review the clinical findings and developmental outcomes of infants with PeV-A and EV meningitis. We performed a retrospective study of infants aged 90 days or younger being admitted to our hospital with PeV-A meningitis between November 2015 and July 2017, with positive cerebrospinal fluid (CSF) PeV-A PCR and negative blood and CSF bacterial cultures. Hearing and neurodevelopmental outcomes were compared with a previous cohort of infants aged 90 days or younger with EV meningitis admitted from January 2015 to December 2015. A total of 161 infants were included in our study, of which 68 infants (42.2%) had PeV-A meningitis and 93 infants (57.8%) had EV meningitis. We assessed their developmental outcome at 6 months, 1 year, and 2 years post-meningitis. At 2 years post-meningitis, three infants with PeV-A meningitis had developmental delay (5.5%), whereas none with EV meningitis had developmental delay. One patient had speech delay and autism spectrum disorder, while two had mild speech delay. When compared with our cohort of EV meningitis ≤90 days old, children with PeV-A meningitis ≤90 days old were more likely to have developmental delay 2 years post-meningitis (odds ratio 2.4, 95% confidence interval 2.0–3.0, p = 0.043). None of the patients with PeV-A or EV meningitis had sensorineural hearing loss or neurological sequelae, such as cortical blindness, oropharyngeal dysphagia, hydrocephalus, epilepsy, or cerebral palsy. Infants with PeV-A meningitis had a significant risk of developmental delay 2 years post-meningitis compared with those with EV meningitis. It is important to follow-up the developmental milestones of infants diagnosed with PeV-A meningitis for at least 2 years; and when they develop developmental delay, to ensure that they receive appropriate intervention.

Climate variability and seasonal patterns of paediatric parainfluenza infections in the tropics: An ecological study in Singapore

OBJECTIVES

Evidence of the relationship between climate variability, air pollution and human parainfluenza virus (HPIV) infections has been inconsistent. We assessed this in a paediatric population from a highly urbanized tropical city-state.

METHODS

We analysed all reports of HPIV infections in children <5 years old obtained from a major specialist women and children's hospital in Singapore. Assuming a negative binomial distribution and using multivariable fractional polynomial modelling, we examined the relations between climate variability, air quality and the risk of HPIV infections, adjusting for time-varying confounders.

RESULTS

We identified 6393 laboratory-confirmed HPIV infections from 2009 to 2019. Every 1 °C decline in temperature was associated with a 5.8% increase (RR: 0.943, 95% Confidence Interval [95% CI]: 0.903-0.984) in HPIV infection risk 6 days later. Every 10% decrease in relative humidity was associated with a 15.8% cumulative increase in HPIV risk over the next 6 days (cumulative RR: 0.842, 95% CI: 0.771-0.919). Rainfall was positively associated with HPIV risk 2 days later (RR: 1.021, 95% CI: 1.000-1.043). A within-year seasonal rise of HPIV was driven by HPIV-3 and HPIV-1 and preceded by a seasonal decline in temperature. Gender was an effect modifier of the climate-HPIV relationship. Air quality was not associated with HPIV risk.

CONCLUSIONS

This study demonstrates a close association between HPIV infection risk and tropical climate variability. The climate dependence and seasonal predictability of HPIV can inform the timing of community campaigns aimed at reducing infection risk and the development of hospital resources and climate adaption plans.

Tropheryma whipplei in Feces of Patients with Diarrhea in 3 Locations on Different Continents

We examined fecal specimens of patients with diarrhea from 3 continents for Tropheryma whipplei and enteropathogens. T. whipplei was most common in South Africa, followed by Singapore and Germany. Its presence was associated with the presence of other pathogens. An independent causative role in diarrhea appears unlikely.

Salmonella Renal Abscess in an Immunocompetent Child: Case Report and Literature Review

We describe a case of a 10-year-old immunocompetent girl with a left renal abscess due to Group C Salmonella (Salmonella serovar Oranienburg). Percutaneous drainage of the abscess was done. She also received 2 weeks of intravenous ceftriaxone, followed by 4 weeks of oral co-trimoxazole with resolution seen on ultrasound. A review of pediatric Salmonella renal abscesses is also presented.

Respiratory viral infections in hospitalised paediatric patients in the tropics

AIM

Respiratory viruses are a huge disease burden globally. An understanding of the seasonal trends and the ability to predict peak periods of respiratory virus disease incidence is useful for clinical care.

METHODS

This is a retrospective analysis of paediatric hospitalizations of laboratory-confirmed viral respiratory tract infections in KK Women's and Children's Hospital, Singapore, from 1 January 2011 to 31 December 2016. Standard direct immunofluorescence was used to detect respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza 1, 2 and 3 viruses, metapneumovirus and adenovirus.

RESULTS

A total of 97 840 specimens were analysed with a positive detection rate of 23.8%. RSV made up the largest proportion (42% of the total positive results), predominating between May to September. Influenza A had two peaks, June to July and December to January. Type 3 was the most common parainfluenza virus and showed annually recurring peaks. In contrast, parainfluenza 1 and 2, metapneumovirus and adenovirus had a biennial pattern. The test of seasonality detected identifiable seasonality for RSV and parainfluenza 3 virus.

CONCLUSIONS

In conclusion, respiratory viruses have different and overlapping seasonality in tropical Singapore. Respiratory virus testing for patients admitted for acute respiratory infection is useful to target antiviral therapies and appropriate infection control practices.