Etiology, antimicrobial resistance, and risk factors of neonatal sepsis in China: a systematic review and meta-analysis from data of 30 years

Abstract Objective To evaluate the regional etiology, antimicrobial resistance (AMR) pattern, and risk factors in neonates with sepsis in China. Methods We performed a systematic review and meta-analysis by searching Medline, Embase, Scopus, and Web of Science in December 2020. Studies of neonatal sepsis from China published between 2011 and 2020 were included. We pooled the proportion of pathogens and calculated the odds ratios of risk factors with 95% CIs using a random-effects model. Results We included 29 studies of 164,750 neonates with sepsis. The studies comprise data from 1990 to 2019. Coagulase-negative staphylococci (CoNS), Escherichia coli and Klebsiella spp accounted for 33% (95% CI 24–43), 17% (13–20), and 14% (11–17), respectively. Group B streptococcus (GBS) was the predominant isolate in early-onset sepsis (EOS) (21%, 95% CI 10–31), while the proportion of CoNS was the largest in late-onset sepsis (LOS) (32%, 95% CI 22–43). Resistance of CoNS to penicillin was found in 95% (95% CI 92–98) of 511 cases and Klebsiella spp to ampicillin in 95% (95% CI 90–99) of 364 cases. Maternal underlying diseases (2.61, 95% CI 1.48–4.61), mechanical ventilation (2.41, 1.37–4.23), central venous catheter placement (2.74, 1.77–4.26), peripherally inserted central catheter (PICC) placement (4.26, 2.80–6.49), multiple antibiotic uses (5.35, 1.85–15.43) and total parenteral nutrition (7.96, 2.04–31.02) were risk factors of neonatal sepsis. Conclusion CoNS, E. coli, and Klebsiella spp were the predominant pathogens in neonatal sepsis in China. AMR was still a significant issue in NICUs. Total parenteral nutrition, multiple antibiotic uses, and PICC placement were the most relevant risk factors.


Introduction
Neonatal sepsis or meningitis was one of the leading causes of neonatal death [1]. The population-level estimate for neonatal sepsis was 2202 per 100,000 live births, with mortality between 11 and 19% [2]. In mainland China, the overall positivity of blood culture examination was 17.0% for neonatal patients with suspected sepsis during the first decade of the twentyfirst century [3]. The difference was found in mortality and microbiological patterns among adult and pediatric patients with sepsis [3]. Broad-spectrum antibiotic drugs were widely used in neonates from China and only 24.2% of neonates received Access antibiotic use, according to a global report using the WHO Essential Medicines List Access, Watch, and Reserve (AWaRe) classification [4]. The antimicrobial resistance (AMR) patterns are becoming a significant issue with high rates of resistance in Gram-negative species and an increasing incidence of multidrug-resistant pathogens [5,6].
Previous publications described the distribution and AMR patterns in neonatal sepsis in different regions of China. Subsequent systematic reviews involved articles mostly published in the Chinese literature without proper quality assessment [3,7,8]. Recently, more studies published in the English literature with a higher quality of design from various provinces have emerged. Therefore, we conducted this systematic review to broadly observe the etiological distribution and AMR patterns, and to identify the risk factors of neonatal sepsis from China.

Search strategy and selection criteria
We performed this systematic review and meta-analysis in line with the preferred reporting items for systematic reviews and meta-analyses (PRISMA) recommendations. A systematic search of Medline, Embase, Scopus, and Web of Science was conducted on 3 December 2020, to identify studies from China published from 1 January 2011, to the date of search. The following terms were used on Scopus in various combinations: "sepsis," "septic," "neonatal," "newborn," "infant," "China," "Chinese." A similar strategy was used in the search of other databases (see Appendix 1). We restricted the language to English and the doctype to article.
Two reviewers (YQY and XRH) screened the abstracts and titles after they were imported into Endnote and the duplicate records were removed. They assessed for relevance to the clinical studies of neonatal sepsis from China. After full-text articles were assessed, studies were excluded if they were studies from other countries or had no data accessible to etiology, AMR, or risk factors of neonatal sepsis. Case reports and studies focused on a single pathogen were excluded because they might lead to biased estimates of the results, especially the etiology of the pathogens and AMR. We defined sepsis as having positive culture results of bacteria or fungus from blood or cerebrospinal fluid samples. Therefore, studies without culture-proven neonatal sepsis were also excluded. Cases of sepsis with positive culture for coagulase-negative staphylococci (CoNS) were identified only if the clinical course was suggestive of sepsis and appropriate antibiotic therapy was given. Disagreements were resolved by discussion with a third reviewer (LJW).

Quality assessment and data extraction
We applied the Strengthening the Reporting of Observational Studies in Epidemiology for Newborn Infection (STROBE-NI) checklist to assess the quality of the observational studies [9]. Two reviewers (YQY and XRH) evaluated the studies independently. The checklist was firstly applied by Okomo et al. in neonates, and we improved the criteria by scores [10]. Each item reporting was classified with "not reported or unclear," "some information mentioned but insufficient," or "clear and detailed information provided," scored as 0, 1, and 2, respectively. Studies with higher total scores had a better quality.
Three reviewers (YQY, XRH, and LJW) independently collected data from the studies included. Information was extracted by a pre-designed form, including study details (publication year, study year, study design, regions and locations, population), number of isolates of the pathogens and AMR, and risk factors of sepsis and mortality.

Statistical analysis
All analyses were pooled using the Dersimonian and Laird method in a random-effects model. We pooled the dichotomous non-comparative data for the etiology of the pathogens and AMR as proportions with 95% CI. We pooled the comparative dichotomous data for risk factors as odds ratios with 95% CI. Heterogeneity was reported as I 2 statistics. Subgroup analysis was undertaken mainly by regions. All statistical analyses were performed with Stata V. 16.0 (StataCorp, College Station, TX, USA).

Quality assessment
The average score for the studies evaluated using STROBE-NI criteria was 32 (range 23-40). 19 (66%) studies reported detailed information in study design, 9 (31%) in setting description, 25 (86%) in the eligibility criteria of participants, and 20 (69%) in the definition of variables. Only 5 (17%) studies had information of bias and 4 (14%) of study size. No information was found in addressing missing data and description of sensitivity analyses in all studies. The main results were clear and detailed in 27 (93%) studies. Because of retrospective designed in most studies, only 5 (17%) had a flow diagram or reported participation in detail. Sixteen (55%) studies gave a cautious overall interpretation of results. Limitations were not reported in 13 (45%) studies (see Appendix 4). Studies included in qualitative synthesis (meta-analysis) (n=29) Figure 1. Study selection.

Etiology
Pooled regional distribution of pathogens in total sepsis, EOS, and LOS were listed in We also observed significant differences in the distribution of pathogens inter-regionally (see Appendix 5). In particular, GBS in neonatal sepsis was reported more common in east China (29%, 95% CI 23-35), than in southern and west China (8%, 95% CI 5-12; 1%, 95% CI À0-3).

Risk factors
Compared with neonates without sepsis, the odds of maternal underlying diseases ( [40]. A meta-analysis of microbiological patterns in neonatal and pediatric patients from different regions of China showed no significant geographical differences in the proportion of pathogens [3]. However, our report firstly performed a meta-analysis of the specific distribution of pathogens from different regions of China in EOS and LOS. We discovered that GBS was the leading cause followed by CoNS and E. coli in EOS. Similarly, the reports from the UK and the US found GBS and E. coli were the most frequently       Figure 2. Risk factors associated with neonatal sepsis. Two studies were involved in Wang et al. [36]. PICC: peripherally inserted central catheter. isolated pathogens in EOS [41][42][43][44]. Huang et al. [45] illustrated the distribution of the maternal GBS colonization in mainland China, and Fujian and Guangdong provinces in southern China had the highest rate of colonization. We also found that the distribution of GBS infection in EOS was significantly higher in east and southern China. GBS had the highest incidence (0.30 per 1000 live births) in EOS in a retrospective study from 2012 to 2016 in southern China, similar to the results from the UK [24,41]. From 2006 to 2015, due to intrapartum antibiotic prophylaxis (IAP), earlyonset GBS disease incidence declined significantly from 0.37 to 0.23 per 1000 live births (p < .001) in the US [46]. Therefore, it is necessary to highlight the importance of GBS screening of pregnant women and IAP especially in regions with high maternal GBS colonization rates of China. Furthermore, we found that CoNS, Klebsiella spp, and E. coli were the predominant isolates in LOS. It was reported that K. pneumoniae and A. baumannii were the most frequently identified organisms causing nosocomial pneumonia, whereas CoNS was the most common pathogen causing nosocomial bloodstream infection in China [47,48]. A prospective study from Taiwan showed a high prevalence of nosocomial infections (17.5%) between 2004 and 2005, including central intravascular catheter-associated bloodstream infection (13.7%), total parenteral nutrition (TPN)-associated bloodstream infection (15.8%), and ventilatorassociated pneumonia (18.6%) [49]. More efforts     should be taken to perform quality improvement in hospitalization and the use of life-sustaining medical devices in NICUs.
Our results of AMR patterns were under the studies from Li et al. and Zhang et al. [7,8]. Also, the proportion of Gram-negative cultures resistant to third-generation cephalosporins was as high as the data from the NeoAMR network [5]. Zhu et al. [14] found that resistance of ESBL-producing multi-drug resistant E. coli to third-generation cephalosporins increased from 2002 to 2018. In general, initial empirical treatment of earlyonset bacterial infections includes ampicillin plus aminoglycoside, with a third-generation cephalosporin or carbapenem for meningitis. In LOS, initial empirical treatment consists of vancomycin plus aminoglycoside, and cephalosporin if meningitis is suspected [50]. Aminoglycosides have rarely been used in children in China due to ototoxicity since 2000 [33]. More awareness should be raised on the increasing high resistance to third-generation or fourth-generation cephalosporins in Gram-negative organisms. The Surveillance and Correction of Unnecessary Antibiotic Therapy (SCOUT) study reduced antibiotic use in a level 3 NICU from the US and presented the feasibility in optimizing antibiotic stewardship strategies [51]. A program called Smart Use of Antibiotics Program (SMAP) also showed effectiveness in reducing antibiotic exposure in a NICU in Shanghai, China [52]. Further work is required to reduce AMR infection in NICUs in China and worldwide.
Risk factors of neonatal sepsis were less reported in studies from China. In 2014, the Kaiser Permanente Division of Research developed a neonatal EOS risk calculator in newborns !34 weeks' gestation [53]. The use of EOS calculators has increased worldwide. Recent studies proved that the implementation reduces the need for diagnostic testing and empirical antibiotic treatment for suspected EOS substantially [54,55]. However, the application in non-Western countries, especially with different health care settings, needs further exploration.
The strengths of this study are the wide description of the characteristics of neonatal sepsis in China and the rigorous quality assessment of the included studies. However, there are some limitations remain. Firstly, high heterogeneity was found in the distribution of isolates and drug resistance. Characteristics of sepsis were different in hospitals intra-regionally and inter-regionally. Secondly, the literature search only included articles published in the last 10 years and the language was restricted to English, which may result in a risk of bias.
Our meta-analysis was based on the data of 30 years, therefore, the changing trends of the characteristics may lead to high heterogeneity. Characteristics of 4 studies including data of different periods were listed in Appendix 7. The AMR to gentamicin was declined, and the AMR to ampicillin and piperacillin-tazobactam increased in the last 30 years. Lu et al. [33] presented the trends of pathogens and AMR profiles in southwest China from 1990 to 2014. The occurrence rates of pathogens remained stable during the study period. A recent study from Suzhou, China also found a significant reduction in CoNS and K. pneumoniae, and a reduced sensitivity against the first-and second-generation antibiotics in the last decade [56]. Care bundles were applied in different countries these years, including China [57]. Meta-analysis revealed a statistically significant reduction in central line-associated bloodstream infections (CLABSIs) following the introduction of care bundles (RR 0.40, p < .00001) [58]. From 2015, a national group named Neonatal Intensive Care Units using the Evidencebased Practice for Improving Quality study (REIN-EPIQ Study Group) of twenty-five tertiary hospitals from 19 provinces in China has been established. The efforts in quality improvement in NICUs may be beneficial to reduce neonatal infection in the future.

Conclusions
In conclusion, our study was the first study to broadly describe the characteristics of neonatal sepsis in China with a high-quality assessment of publications. We expect our research could provide more evidence for informing guidelines and better clinical care of neonatal sepsis in different regions of China. The results may be recommended as comparisons with studies carried out in other countries and as implications for global practice in the treatment and prevention of neonatal sepsis.

Disclosure statement
The authors report no conflict of interest.

Author contributions
YQY designed the study and drafted the initial manuscript. YQY, XRH, and LJW collected the data. YQY, XRH, and YHY analyzed the data. All authors reviewed and revised the manuscript. PYC contributed to the concept, coordinated and supervised data collection, and critically reviewed the manuscript for important intellectual content. All authors approved the final manuscript as submitted.

Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information. Data are available from the corresponding author.