Impact of 1% chlorhexidine gluconate bathing and emollient application on bacterial pathogen colonization dynamics in hospitalized preterm neonates – A pilot clinical trial

Background: Chlorhexidine gluconate (CHG) body washes and emollient application may modulate bacterial pathogen colonization and prevent neonatal hospital-acquired infections. Methods: This pilot, non-randomized, open-label trial, enrolled preterm neonates (1000-1500g; day 1-3 of life) at a tertiary hospital in Cape Town, South Africa. Participants were sequentially allocated to 4 trial arms (n=20 each): 1% aqueous CHG (CHG), 1% CHG plus emollient (CHG+EM), emollient only (EM) and standard of care (SOC: no antiseptic/emollient). Trial treatment/s were applied daily for 10 days (d) post-enrolment, documenting neonatal skin condition score. Anterior nose, neck, umbilical and perianal swabs for bacterial culture were collected at d1, d3, d10 and d16 post-enrolment, (±1 day), reporting pathogen acquisition rates and semi-quantitative bacterial colony counts. (ClinicalTrials.gov identifier: NCT03896893; trial status: closed). Findings: Eighty preterm neonates (mean gestational age 30 weeks [SD 2]) were enrolled between 4 March and 26 August 2019. The bacterial pathogen acquisition rate (comparing d1 and d16 swabs) varied from 33·9% [95%CI 22·9-47·0] at the umbilicus, 39·3% [95%CI 27·6-52·4] at the neck, to 71·4% [95%CI 58·5-81·7] at both the nose and perianal region. At d10, CHG babies had reduced bacterial density detected from neck, umbilicus, and perianal swabs compared to other groups (see Table 3). Following intervention cessation, colonization density was similar across all trial arms, but S. aureus colonization was more prevalent among EM and CHG+EM babies. Neonatal skin condition score improved in babies receiving emollient application (EM: -0·87 [95%CI 0·69-1·06] and CHG+EM: -0·73 [0·45-0·99]), compared to the SOC and CHG arms (Table 2); no CHG-related skin reactions occurred. Interpretation: Bacterial colonization density was significantly reduced in babies receiving 1% CHG washes but colonization levels rebounded rapidly post-intervention. Emollient application improved skin condition but was associated with higher rates of S. aureus colonization. Funding: South African Medical Research Council; National Institutes of Health (TW010682). We conducted a non-randomized, open-label, pilot clinical trial in a convenience sample of hospitalized neonates admitted to Tygerberg Hospital, Cape Town, South Africa between March and August 2019. The Stellenbosch University Health Research Ethics Committee and the Tygerberg Hospital management reviewed and approved the study protocol (N18/07/068; ClinicalTrials.gov identifier: {“type”:”clinical-trial”,”attrs”:{“text”:”NCT03896893″,”term_id”:”NCT03896893″}}NCT03896893). The manuscript was prepared in accordance with the CONSORT statement checklist for reporting of clinical trials. Tygerberg Hospital is a 1384-bed public teaching hospital with a busy obstetric-neonatal service that manages approximately 8000 high-risk deliveries (37% low birth weight rate) and 3000 neonatal admissions annually. Despite being classified as an upper middle-income country by the World Bank, most patients using the public healthcare service are indigent and more typical of the population from low and lower middle-income countries. In 2017, the antenatal HIV prevalence in the Western Cape Province was 15·9% (95% CI: 14·2%–17·8%), with universal antiretroviral therapy in pregnancy and a national mother-to-child HIV infection transmission rate of 0·9% [23]. The neonatal unit (being the second largest neonatal inpatient unit in the country) comprises 132 beds including a 12-bed medical/surgical NICU, three high-dependency wards, and one kangaroo mother care ward. The neonatal unit provides medical and surgical care for sick, preterm (<37 weeks’ gestation) and/or low-birthweight (<2500 g) inborn and outborn neonates from surrounding district hospitals and midwife obstetric units. Prematurity, perinatal asphyxia and infection are the most common indications for admission. Critically ill neonates are nursed in the NICU, with availability of respiratory support (conventional ventilation, oscillation and nasal continuous positive airway pressure [nCPAP]), inotropic support and nitric oxide therapy). Given the extreme shortage of NICU beds, non-invasive ventilation (nCPAP and high-flow oxygen therapy) is used extensively in the high-dependency wards. Prior to this pilot trial, CHG bathing and emollient therapy was not used in the neonatal unit. 2% CHG in 70% alcohol was used for skin antisepsis prior to central line insertion for neonates >28 weeks gestational age. Aqueous 0·5% CHG body washes were occasionally used for methicillin-resistant Staphylococcus aureus (MRSA) decolonization during outbreaks in the neonatal wards. At our institution, the standard practise for per vaginal (PV) examinations in labour is to use sterile gloves without prior vaginal washes. Neonates were eligible for enrolment if they fulfilled the following criteria: birth weight ≥1000g and ≤ 1500g (equivalent to gestational age 28–32 weeks); aged from day 1 – 4 of life; and anticipated length of hospital stay > 7 days. Neonates whose mothers were not present, unable or unwilling to provide consent for enrolment and neonates with any skin condition or congenital defect that could enhance CHG absorption were excluded. All potentially eligible neonates’ parents were approached for consent to trial participation and provided written informed consent. Preterm neonates (1000-1500g; day 1-4 of life) were sequentially allocated to 4 trial arms (n=20 each) with no randomization, no allocation concealment and no masking): 1% aqueous CHG (CHG); 1% CHG plus emollient (CHG+EM); emollient only (EM) and standard of care (SOC – no antiseptic/emollient). As this was a pilot trial with limited funding and minimal staffing, the trial design was intentionally simple. Sequential allocation to trial arms (starting with the CHG-containing arms) was chosen to facilitate closer observation for CHG skin reactions at the start of the trial, in case reduction in the CHG concentration to 0.5% was needed. Trial interventions (CHG, EM and CHG+EM) were applied daily from the neck down on weekdays by the trial investigators. Single named-patient containers of CHG +- emollient (where applicable) were used per patient. All interventions were discontinued 10 days post-enrolment. CHG was applied to 2 sterile cotton swabs with care taken to avoid pooling of CHG in skin folds. For neonates on the EM and CHG+EM arm, 2 grams of Aquaphor skin cream (Eucerin, Beiersdorf, Germany) was applied (as soon as the CHG had dried for babies on CHG + EM). Skin temperature (using an axillary thermometer) was recorded immediately before and 5 minutes after application of the trial intervention/s. Neonates on the CHG-containing arms were observed for skin reactions for 30 minutes following application of CHG. Swabs in liquid Amies transport medium (Sigma Transwab MWE) for bacterial culture were obtained from neonates’ anterior nares (nose), neck folds, umbilicus/umbilical stump and perianal area prior to application of trial interventions on day 1 (enrolment), day 3, day 10 and day 16 post-enrolment (all +- 1 day). The liquid transport medium in the swab tube was vortexed for 30 seconds and diluted 1:100 and 1:10 000 in normal saline. 25 mL of the fluid was inoculated onto blood and MacConkey agar plates, and 25 mL of each of the two dilutions was inoculated onto blood agar plates. All agar plates were incubated at 37oC for 24 hours, and for a further 24 hours if no growth was observed. Manual total, semiquantitative aerobic colony counts (ACC) were recorded for each specimen. Isolates were identified by Gram stain and then catalase, pyrrolidonyl aminopeptidase activity, and/or latex agglutination (Pastorex Staph-Plus; Bio-Rad, Redmond,WA) for gram positive organisms, or the automated Vitek-2 system (BioMerieux, Marcy-l’Étoile, France) for gram negative isolates. Patient records were reviewed daily to collect demographic, clinical, laboratory and antimicrobial prescription data; data were entered into an institutional-hosted REDCap database [27]. HA-BSI were defined as a positive blood culture yielding a known neonatal pathogen (based upon the categorization of the United States Centers for Disease Control and Prevention, US CDC) [25] obtained at ≥72 hours of life/hospitalization. Clinically-suspected infection included neonates with negative laboratory culture results, but symptoms, signs and/or raised markers of infection e.g. C-reactive protein >10mg/L, where at least 5 days of broad-spectrum antibiotic therapy was given. A neonatal skin condition scale assessment (skin score) developed by Darmstadt et al was performed on weekdays before application of trial interventions until day 14 post-enrolment [19]. The skin score had a 3-criteria grading system (dryness, erythema, skin breakdown) with a minimum score of 3 and a maximum possible score of 9 (grading dryness: 1 = normal, no sign of dryness; 2 = dry skin, visible scaling; 3 = very dry skin, cracking/fissures; erythema: 1 = no evidence of erythema; 2 = visible erythema < 50% body surface; 3 = visible erythema > 50% body surface and breakdown: 1 = none; 2 = small localized areas; 3 = extensive breakdown). Our primary outcome of interest was the change in pathogen colonization density at the four selected body sites from baseline (day 1) to days 3, 10 and 16 post-enrolment. Secondary outcomes were the rate of acquisition of pathogenic bacteria (gram negative and gram positive), the neonatal skin score and development of adverse events (AE’s) or serious AE’s e.g. hypothermia, CHG skin reactions, laboratory-confirmed and/or clinically-suspected infection. Neonates were observed until day 28 post-enrolment or until neonatal hospital transfer/discharge with telephonic follow-up on day 28 post-enrolment. Descriptive analysis of neonatal and maternal demographic characteristics by trial arm was performed, reporting means with standard deviations or 95% confidence intervals for normally distributed data and medians with interquartile ranges for non-normally distributed data. Categorical variables were reported as counts and percentages. The proportion of neonates acquiring one or more new pathogen/s (comparing d1 and d16 swabs) was reported as the percentage with 95% confidence intervals (CI) for each body site swabbed. Density of skin colonization with pathogens was reported for all participants in log CFU/ml and compared between trial arms at each swabbing timepoint using the Kruskal-Wallis test. For all statistical tests performed, a p-value <0.05 was considered significant. All the statistical analyses were performed using STATA 16·0 (College Station, Texas 77845 USA). The funders of the trial had no role in trial design, data collection, data analysis, data interpretation, or writing of the report. The corresponding author had full access to all the data in the trial and had final responsibility for the decision to submit.