A Yersiniabactin-producing Klebsiella aerogenes Strain Causing an Outbreak in an Austrian Neonatal Intensive Care Unit.

BACKGROUND: Yersiniabactin, a siderophore with a high affinity to iron, has been described as a potential virulence factor in Enterobacteriaceae. Klebsiella aerogenes is a Gram-negative rod known to cause invasive infection in very low birth weight infants but is an unusual pathogen to cause outbreaks in neonatal intensive care units (NICU). METHODS: We performed a retrospective analysis of all patients colonized with K. aerogenes in our NICU from September to December 2018. Each infant with an occurrence of K. aerogenes in any microbiological culture was defined as a case. Clinical data were taken from medical charts. K. aerogenes isolates were genotyped using whole-genome sequencing combined with core genome multilocus sequencing type analysis. Yersiniabactin production was evaluated by luciferase assay. RESULTS: In total 16 patients were colonized with K. aerogenes over the 3-month period and 13 patients remained asymptomatic or developed late-onset neonatal sepsis from another pathogen. Three patients developed necrotizing enterocolitis, 2 complicated by sepsis and 1 of them died. All symptomatic patients were premature infants with low birth weight. Genetic sequencing confirmed an outbreak with the same strain, all samples expressed the high-pathogenicity island, necessary for the production of yersiniabactin. Six exemplary cases were proven to produce yersiniabactin in vitro. CONCLUSION: This is the first report of an outbreak of a yersiniabactin-producing K. aerogenes strain causing invasive infection in preterm infants. We hypothesize that, due to improved iron uptake, this strain was associated with higher virulence than non-yersiniabactin-producing strains. Extended search for virulence factors and genetic sequencing could be pivotal in the management of NICU outbreaks in the future.

One year into the SARS-CoV-2 pandemic: perinatal outcome and data on the transmission of 116 pregnant women.

OBJECTIVES: Report of clinical data on maternal outcomes, mode of delivery and immediate neonatal outcome in women infected with COVID-19, as well as clarifying whether the transmission of SARS-CoV-2 could occur in utero (congenital), intrapartum, and/or postnatally through breastmilk, amniotic fluid or cord blood. METHODS: Retrospective data collection. Evidence of vertical transmission was assessed by testing for SARS-CoV-2 in amniotic fluid, cord blood, maternal liquor, breast milk and neonatal pharyngeal swab samples. RESULTS: 8.9% (n=8) of the total population of hospitalized SARS-CoV-2 positive pregnant women were admitted to a critical care unit, one (0.9%) needed extracorporal membrane oxygenation (ECMO) and one woman died (0.9%). The premature birth rate before 34+0 weeks of gestational age of 8.2% (n=8) among pregnant women who tested positive for SARS-CoV-2, was almost four times higher than among the total population of pregnant women in Austria. Two newborns (2%) were tested positive for SARS-CoV-2 after birth. No SARS-CoV-2 was found in amniotic fluid, cord blood, maternal liquor or breast milk using polymerase chain reaction (PCR). CONCLUSIONS: Pregnant women with COVID-19 seem to be at a higher risk of invasive ventilation, admission to a critical care unit and pre-term birth and therefore they should be considered as a high-risk population. The risk of congenital or intrapartal infection seems to be insignificant.

SARS-CoV-2 in pregnancy: maternal and perinatal outcome data of 34 pregnant women hospitalised between May and October 2020.

OBJECTIVES: To report clinical data on maternal outcome, mode of delivery and immediate neonatal outcome in women infected with COVID-19. METHODS: Retrospective data collection. RESULTS: A total of 8.6% of the total population of hospitalised SARS-CoV-2 positive pregnant women were admitted to a critical care unit. The premature birth rate for births before 34+0 weeks of gestation among pregnant women who tested positive for SARS-CoV-2 was 7.1%. One newborn (3.6%) tested positive for SARS-CoV-2 two days after birth and showed symptoms. CONCLUSIONS: Pregnant women with COVID-19 seem to be at higher risk of invasive ventilation, admission to a critical care unit and preterm birth, and should therefore be considered a high-risk-population.

Probiotics (Lactobacillus acidophilus and Bifidobacterium infantis) prevent NEC in VLBW infants fed breast milk but not formula [corrected].

BACKGROUND: Specific probiotics prevent necrotizing enterocolitis (NEC). A mixture of lactobacilli and bifidobacteria (Infloran) was highly effective in Asian very-low-birth-weight (VLBW) infants. We analyzed the effect of Infloran on NEC, NEC severity, and the influence of enteral feedings (breast milk vs. formula) on NEC prevention in a cohort of European VLBW infants. METHODS: Infloran was implemented for routine use at our department. VLBW infants receiving probiotics were prospectively followed (2010-2012) and compared with historic controls (2008-2009). Data on NEC, neonatal morbidity, feeding tolerance, and descriptive parameters on NEC cases were analyzed. RESULTS: Infloran had no statistically significant impact on NEC (controls: 24/233 (10.3%); probiotics: 16/230 (7%); P = 0.2). However, NEC was significantly reduced in infants of the probiotics group who were fed any breast milk (20/179 (11.2%) vs. 10/183 (5.5%); P = 0.027), whereas it was ineffective in infants exclusively fed formula (4/54 (7.4%) vs. 6/44 (13.6%); P = 0.345). Occurrence of severe NEC (IIIb), time until full feeds, and gastric residuals were similar. CONCLUSION: Infloran was of lower efficacy in a European VLBW cohort and showed a reduction of NEC only in infants fed breast milk. Future studies should investigate the influence of feeding formula or breast milk on the effect of probiotics.