Mucosal surveillance cultures in predicting Gram-negative late-onset sepsis in neonatal intensive care units.

This study aimed to examine the spectrum and time course of gut and nasopharyngeal colonization with Gram-negative micro-organisms, and to define the value of surveillance cultures in predicting late-onset sepsis in neonates admitted to neonatal intensive care units. Nasopharyngeal and rectal swabs were collected on admission and twice weekly thereafter in 278 neonates admitted within the first 72 h of life with risk factors of early-onset sepsis. Sterile body fluid cultures were obtained on admission and subsequently as clinically indicated. Approximately half of the rectal (693/1250, 55%) and nasopharyngeal (558/1153, 48%) samples but only 6% (32/555) of the sterile fluid samples in 26 patients were culture positive for Gram-negative organisms. In total, 2108 invasive and mucosal culture pairs were analysed. The overall sensitivity, specificity, and positive and negative predictive values of a mucosal sample to predict late-onset sepsis were 27%, 66%, 4% and 94%, respectively. Patients with pre-existing colonization with Klebsiella pneumoniae (P = 0.011), Klebsiella oxytoca (P = 0.002), Escherichia coli (P = 0.003), Stenotrophomonas spp. (P = 0.003) and Pseudomonas spp. (P ≤ 0.001) were more likely to develop late-onset sepsis. No such association was found for Acinetobacter baumannii, Serratia spp. or Enterobacter cloacae. In conclusion, routine mucosal cultures are inefficient for the prediction of Gram-negative late-onset sepsis in neonatal intensive care units. However, targeted screening for specific organisms in an outbreak (e.g. Klebsiella spp., E. coli, Stenotrophomonas spp. and Pseudomonas spp.) may offer an opportunity to improve infection control measures and enable timely initiation of appropriate antibiotic therapy.

Impact of empiric antibiotic regimen on bowel colonization in neonates with suspected early onset sepsis.

The purpose of this study was to compare the impact of ampicillin and penicillin used for empiric treatment of early onset sepsis (EOS) on initial gut colonization by aerobic and facultative anaerobic microorganisms. A cluster-randomized, two-center, switch-over study was conducted in two paediatric intensive care units in Estonia and included 276 neonates. Rectal swabs were collected twice a week until discharge or day 60. Colonizing microbes were identified on species level and tested for ampicillin resistance (AR). The number of patients colonized with Gram negative microorganisms and Candida spp was similar in both treatment arms but ampicillin resulted in longer colonization duration (CD) of K. pneumonia (p = 0.012), AR Serratia spp (p = 0.012) and Candida spp (p = 0.02) and penicillin in that of AR Acinetobacter spp (p = 0.001). As for Gram positive microorganisms penicillin treatment was associated with a greater number of colonized patients and higher CD of Enterococcus spp and S. aureus but lower ones of S. haemolyticus and S. hominis. Influence of ampicillin and penicillin on initial gut colonization is somewhat different but these differences are of low clinical relevance and should not be a limiting step when choosing between these two antibiotics for the empiric treatment of EOS.

Comparison of ampicillin plus gentamicin vs. penicillin plus gentamicin in empiric treatment of neonates at risk of early onset sepsis.

AIM: We aimed to compare the clinical efficacy of ampicillin (AMP) vs. penicillin (PEN) both combined with gentamicin in the empirical treatment of neonates at risk of early onset neonatal sepsis (EOS). METHODS: We performed an open label cluster randomized equivalence study in both Estonian neonatal intensive care units, including neonates with suspected EOS, aged less than 72 h. Primary end-point was clinical failure rate, expressed by need for change of antibiotic regimen within 72 h and/or 7-day all cause mortality. Bowel colonization was followed with biweekly perineal swab cultures. RESULTS: Incidence of proven EOS was 4.9%. Among neonates receiving AMP (n = 142) or PEN (n = 141) change of antibiotic regimen within 72 h (10/142 vs. 10/141; OR 1.02; 95% CI 0.40-2.59), 7-day mortality (11/142 vs. 14/141; OR 0.76; 95% CI 0.33-1.75) and over-all treatment failure (20/142 vs. 20/141; OR 1.01; 95% CI 0.52-1.97) occurred at similar rates. The only differences in gut colonization were lower number of patients colonised with enterococci, S. aureus and AMP resistant Acinetobacter spp. in AMP and lower number of those with S. haemolyticus and S. hominis in PEN arm. CONCLUSIONS: AMP and PEN combined with gentamicin have similar effectiveness in the empiric treatment of suspected neonatal EOS.