Purpose: Neonatal sepsis (NS) has no specific clinical manifestations and blood culture analysis requires a long period of time. Knowledge of prevalent bacterial isolates and their antibiotic susceptibility is crucial when choosing an empirical therapy to decrease morbidity and mortality. This literature review summarizes the distribution characteristics and antimicrobial resistance of bacterial pathogens associated with bloodstream infections in Chinese neonates, and thus serves as a reference for pediatricians.
Methods: The full-text journal database, CNKI, was searched using the key words "neonatal", "sepsis", and "bacterial pathogen" to retrieve relevant literature published from 2016 up to April 2018. The following data were extracted from the selected papers: title, pathogen collection time, care unit name, province (city), distribution of bacterial pathogens among bloodstream infections, and antimicrobial resistance of major pathogens.
Results: A total of 86 articles were searched, of which 30 complied with the study requirements and thus were included in the review; all were retrospective studies. The articles covered a total of 4098 bacterial strains from 24 cities (2494 Gram-positive bacteria, 1429 Gram-negative bacteria, 176 fungi). Among the Gram-positive bacteria, the four pathogens with the highest detection rates were coagulase-negative staphylococci (CoNS) (40.23%), Streptococci (6.81%), Enterococci (6.10%), and Staphylococcus aureus (S. aureus) (5.15%); among the Gram-negative bacteria, Klebsiella (14.52%), Escherichia coli (12.12%), Enterobacter cloacae (1.90%), and Pseudomonas (1.41%) had the highest detection rates. The detection rate of Candida and other fungi was 4.29%. Among the pathogens with high clinical detection rates, S. epidermidis and S. aureus are highly resistant to both erythromycin and penicillin. Antibacterial drugs with high efficacy for both S. epidermidis and S. aureus include vancomycin, ciprofloxacin, gentamicin, linezolid, rifampicin, and tetracycline. Klebsiella pneumoniae and Escherichia coli are highly resistant to ampicillin, but there are drugs with high efficacy for both, including imipenem, piperacillin/tazobactam, aminoglycosides (gentamicin, amikacin), and quinolones (levofloxacin, ciprofloxacin). In contrast to the drug resistance data reported by the China Antimicrobial Resistance Surveillance System (CARSS) in 2017, the detection rate of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRCoNS) in the blood cultures of neonates with sepsis exceeded the national average drug resistance level (p < .01). The resistance rate of K. pneumoniae to third-generation cephalosporins was higher than the national average drug resistance level (p < .01), but this organism was most sensitive to carbapenems (carbapenem resistance refers to resistance to any of imipenem, meropenem, or ertapenem). The resistance of Escherichia coli to quinolones was better than the national average level (p < .01).
Conclusions: Medical care-related infections in neonatal intensive care units (NICUs) were more often caused by CoNS than by S. aureus and Gram-negative bacteria. Vancomycin remains the preferred drug for treating confirmed infections, because most isolated CoNS are resistant to β-lactam drugs including penicillin. For Gram-negative enteric bacteria, aminoglycoside and carbapenem were sufficient for treatment. Compared to the CARSS data on bacterial resistance, the data in this review on the resistance of pathogens causing NS were not favorable. The next goal in antibiotic management in NICUs must be to develop strategies to reduce the use of antibiotics.
Keywords: Antimicrobial resistance; distribution characteristics; literature study; neonatal sepsis.