Molecular epidemiology of Streptococcus pneumoniae isolated from pediatric community-acquired pneumonia in pre-conjugate vaccine era in Western China.

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is one of the most common pathogens which can cause morbidity and mortality in pediatric infections worldwide. This study aimed to describe the phenotypic and molecular characteristics of community-acquired pneumonia (CAP)-causing S. pneumoniae recovered from children in Western China. METHODS: We retrospectively enrolled pediatric patients younger than 5 years diagnosed with CAP. All 419 S. pneumoniae isolates were tested for antibiotic susceptibility, serotypes, virulence genes, resistance genes, and sequence types. The potential relationships between molecular characteristics were tested by correspondence analysis. RESULTS: Most of S. pneumoniae isolates were resistant to erythromycin, tetracycline, clindamycin and trimethoprim-sulfamethoxazole, with 93.8% isolates classified as multidrug resistant. The dominant STs were ST271 (30.8%) and ST320 (12.2%), while the prevailing serotypes were 19F (46.8%), 6B (11.5%), 23F (9.5%) and 19A (9.3%). The coverage rates of PCV-7 and PCV-13 were 73.03% and 86.16%, while the coverage rates of PCV13 among children aged < 1 year and 1-2 years were high in 93.18% and 93.62%. We also observed that CC271 expressed more of mef (A/E), lytA, rlrA and sipA than non-CC271 isolates. Moreover, there were strong corresponding relationships between molecular characteristics. CONCLUSIONS: The high coverage rate of PCV13 suggests the necessity of introducing the PCV13 vaccine in Western China. Our findings underscore the value of monitoring multiple molecular characteristics to provide new guidance for developing future pneumococcal vaccines.

The association between ambient air pollution and birth defects in five major ethnic groups in Liuzhou, China.

BACKGROUND: Studies suggest that exposure to ambient air pollution during pregnancy may be associated with increased risks of birth defects (BDs), but conclusions have been inconsistent. This study describes the ethnic distribution of major BDs and examines the relationship between air pollution and BDs among different ethnic groups in Liuzhou city, China. METHODS: Surveillance data of infants born in 114 registered hospitals in Liuzhou in 2019 were analyzed to determine the epidemiology of BDs across five major ethnic groups. Concentrations of six air pollutants (PM2.5, PM10, SO2, CO, NO2, O3) were obtained from the Liuzhou Environmental Protection Bureau. Logistic regression was used to examine the associations between ambient air pollution exposure and risk of BDs. RESULTS: Among 32,549 infants, 635 infants had BDs, yielding a prevalence of 19.5 per 1000 perinatal infants. Dong ethnic group had the highest prevalence of BDs (2.59%), followed by Yao (2.57%), Miao (2.35%), Zhuang (2.07%), and Han (1.75%). Relative to the Han ethnic group, infants from Zhuang, Miao, Yao and Dong groups had lower risks of congenital heart disease, polydactyly, and hypospadias. The Zhuang ethnic group had higher risks of severe thalassemia, cleft lip and/or palate, and syndactyls. Overall BDs were positively correlated with air pollutants PM10 (aOR =1.14, 95% CI:1.12 ~ 2.43; aOR =1.51, 95% CI:1.13 ~ 2.03 for per 10µg/mg3 increment) and CO (aOR =1.36, 95% CI:1.14 ~ 2.48; aOR =1.75, 95% CI:1.02 ~ 3.61 for every 1 mg /m3 increment) in second and third month of pregnancy. SO2 was also significantly associated with BDs in the second month before the pregnancy (aOR = 1.31; 95% CI: 1.20 ~ 3.22) and third month of pregnancy (aOR =1.75; 95% CI:1.02 ~ 3.61). Congenital heart disease, polydactyl, cleft lip and/or palate were also significantly associated with PM10, SO2 and CO exposures. However, no significant association was found between birth defects and O3, PM2.5 and NO2 exposures (P > 0.05). CONCLUSION: This study provides a comprehensive description of ethnic differences in BDs in Southwest China and broadens the evidence of the association between air pollution exposure during gestation and BDs.

Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae causing invasive diseases in China: a meta-analysis.

BACKGROUND: To summarize information about invasive pneumococcal disease (IPD) among children in mainland China. METHODS: Sixteen eligible studies were included in this systematic review and the random effect model was used to estimate the pool prevalence of IPD. RESULTS: The most predominant serotypes circulating in children were 19F (27.7, 95% confidence interval (95% CI): 17.7-37.6%), 19A (21.2%, 16.4-26.1%), 14 (16.5%, 12.8-20.1%), 6B (8.6%, 5.2-10.8%) and 23F (7.3%, 5.2-9.5%). The serotype coverage of the available pneumococcal conjugate vaccines PCV7, PCV10, and PCV13 was 60.8% (52.5-69.4%), 65.1% (57.7-72.4%), and 90.0% (87.1-92.8%), respectively. The pooled antibiotic resistance rates of Streptococcus pneumoniae revealed a resistance to penicillin prevalence rate of 32.0% (12.1-51.9%). Approximately 94.4% (90.7-98.1%) and 92.3% (87.4-97.3%) of isolates were resistant to erythromycin and clindamycin. eBURST analysis revealed great diversity among isolates, with 102 sequence types (STs) for 365 isolates. The major predominant clonal complexes (CCs) were CC271 (43.6%, 159/365), CC876 (13.4%, 49/365), CC81 (5.2%, 19/365), and CC90 (4.1%, 15/365). Long-term and regional surveillance of S. pneumoniae is necessary. CONCLUSIONS: Based on our pooled results showing that PCV13 coverage of the reported serotypes was 90% and that most serotypes contributed to the distribution of antibiotic-resistant isolates, implementation of PCV13 into the Chinese Expanded Program on Immunizations (EPI) would achieve health benefits in Chinese children.

Group B streptococcal colonization in mothers and infants in western China: prevalences and risk factors.

BACKGROUND: The epidemiology of maternal and infant Group B streptococcus (GBS) colonization is poorly understood in China. The aim of this study is to explore the prevalence and risk factors associated with maternal and infant GBS colonization in Western China. METHODS: From January 2017 to June 2017, a prospective study was conducted to estimate the maternal and infant GBS colonization rate by maternal rectovaginal and infant nasopharynx, ear canal and umbilical swab culture. Patient demographics, clinical characteristics and outcomes were collected. Chi-square and logistic regression analyses were used to examine the risk factors associated with GBS colonization of mothers and infants. RESULTS: The GBS colonization rate in mothers and infants was 6.1 and 0.7%, respectively. The vertical transmission rate was 7.6%. The early onset GBS infection rate was 0.58 per 1000 live births and mortality was 0.29 per 1000 live births. Age younger than 40 years (p = 0.040) and minority ethnic status (p = 0.049) were associated with higher GBS colonization rate in pregnant women. Positive GBS status in the mother prior to delivery (p < 0.001) as well as longer duration of membrane rupture (≥12 h) (p < 0.001) and longer labor (≥4 h) (p < 0.001) were all significant risk factors for GBS colonization in infants. Compared to infants without GBS colonization, infants colonized with GBS were more likely to have had a temperature of ≥38 °C (p < 0.001), developed early onset infection (EOD) (p < 0.001), and been prescribed antibiotics (p < 0.001). Furthermore, infants with GBS were more likely to have been admitted to neonatal intensive unit (NICU) (p < 0.001) with a longer hospital length of stay (LOS) (p < 0.001). CONCLUSIONS: Maternal GBS colonization, longer duration of membrane rupture and labor were all major risk factors associated with GBS colonization in Chinese infants. Infant GBS colonization was associated with increased risk of EOD and NICU admission as well as longer LOS.

Epidemiology of birth defects based on surveillance data from 2011-2015 in Guangxi, China: comparison across five major ethnic groups.

BACKGROUND: The causes of birth defects (BDs) are complex and include genetic and environmental factors and/or their interactions. More research is needed to describe the epidemiology of BDs within specific regions of China. This study focused on differences in the prevalence of BDs based on ethnicity in a large city in Guangxi Province, China. METHODS: Surveillance data of infants born in 114 registered hospitals in Liuzhou between 2011 and 2015 were analyzed to determine the epidemiology of BDs across five major ethnic groups. We calculated the prevalence of BDs and relative risk of BDs by ethnicity. RESULTS: There were 260,722 perinatal infants of which 6581 had BDs, with the average prevalence of 25.24 per 1000 perinatal infants (PIs). Prevalence data showed an obvious uptrend over the past 5 years. Han had the highest prevalence of total BDs (28.98‰), followed by Zhuang (25.19‰), Yao (18.50‰), Miao (15.78‰) and Dong (14.24‰). Relative to the Han; Zhuang, Miao, Yao, and Dong had a lower risk of musculoskeletal and urogenital malformations; Miao and Yao had a lower risk of cardiovascular malformation; and Dong had a lower risk of cardiovascular and craniofacial malformation. Several maternal risk factors were found to be associated with BDs (e.g., maternal and gestational age, number of antenatal care visits). CONCLUSION: This study provided a comprehensive description of ethnic differences in the risk of BDs in Liuzhou City, China. Observed ethnic differences in the risk of BDs may be related to genetic susceptibilities, environment, cultural customs, or to potential combinations of these factors.

Molecular characterization and antimicrobial susceptibility of Staphylococcus aureus isolated from children with acute otitis media in Liuzhou, China.

BACKGROUND: There have been few studies focused on the prevalence, bacterial etiology, antibiotic resistance, and genetic background of Staphylococcus aureus (S. aureus) in children with acute otitis media (AOM) in China. METHODS: A retrospective study was conducted in Liuzhou Maternity and Child Healthcare Hospital. Patients younger than 18 years diagnosed with AOM were enrolled in the study. Middle ear fluid specimens were collected and cultured for bacterial pathogens. The antibiotic susceptibility, virulence genes, macrolide resistant genes and sequence types of S. aureus were identified. RESULTS: From January 1, 2013 to December 31, 2015, a total of 228 cases of AOM were identified. Pathogenic bacteria were positive in 181 (79.4%) of 228 specimens. Streptococcus pneumoniae was the most common bacteria (36.4%), followed by S. aureus (16.2%). Among the 37 S. aureus isolates, 12 (23.5%) were methicillin-resistant S. aureus (MRSA), and 25 (77.5%) were methicillin-susceptible S. aureus (MSSA). A total of 23 isolates (62.2%) were resistant to erythromycin, 40.5% of isolates were resistant to clindamycin, and 37.8% isolates were resistant to tetracycline. Twenty-three isolates were multi-drug resistant (MDR) S. aureus. Eighteen isolates carried the pvl gene. Up to 22 (59.4%) isolates expressed ermA gene, 8 (21.6%) isolates expressed both ermA and ermC genes, and only 8.1% expressed ermB. Among all S.aureus isolates, 7 sequence types (STs) were identified by multilocus sequence typing (MLST). The most common ST was ST59 (16/37, 43.2%), followed by ST45 (7/37, 18.9%) and ST30 (7/37, 18.9%). The predominant MSSA isolates were ST59-t437-MSSA (5/25, 20.0%), the prevailing MRSA isolates were Taiwan related strains ST59-SCCmec-IVa/V (5/12, 41.6%). CONCLUSIONS: S. aureus was the second most common cause for AOM in children in Liuzhou. Most of the S. aureus was MDR which carried a high proportion of ermA and ermC gene. CA-MRSA (ST59-SCCmec-IV/V-t437) is circulating in children with AOM. These findings support continued surveillance of S. aureus infections in children with AOM in both communities and hospitals.

Prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae in China: a meta-analysis.

BACKGROUND: To explore the overall prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae(S. pneumoniae) among healthy children. METHODS: A search for pneumococcal nasopharyngeal carriage studies including children published up to July 31th, 2016 was conducted to describe carriage in China. The review also describes antibiotic resistance in and serotypes of S. pneumoniae and assesses the impact of vaccination on carriage in this region. Summary measures for overall prevalence, antibiotic resistance, and serotype distributions extracted from the analyzed data were determined with 95% confidence intervals (CIs) using random-effects models. Heterogeneity was assessed using I 2 test statistics. RESULTS: Thirty-seven studies were included in this review, and the majority of studies (64.9%) were located in the pre-introduction period of 7-valent pneumococcal conjugate vaccine (PCV7) in China. The pooled prevalence of S. pneumoniae nasopharyngeal carriage was 21.4% (95% CI: 18.3-24.4%). Carriage was highest in children attending kindergartens [24.5%, (19.7-29.3%)] and decreased with increasing age. Before the introduction of PCV7 into China, the prevalence of S. pneumoniae nasopharyngeal carriage was 25.8% (20.7-30.9%), the pooled carriage of S. pneumoniae sharply dropped into the 14.1% (11.3-16.9%) by PCV7 vaccination period (P < 0.001). Before the pneumococcal conjugate vaccine (PCV) was introduced in China, the penicillin resistance rate in S. pneumoniae isolated from healthy children was 31.9% (21.2-42.6%); however, this rate sharply decreased after the introduction of PCV7 in China [21.6%, (7.4-35.9%)], and the difference between the rates during these two time periods was statistically significant (P value <0.05). Serotypes 19F, 6A and 23F were the most commonly isolated. Meta-analysis of data from young children showed a pooled rate estimate of 46.6% (38.8-54.4%) for PCV7 vaccine coverage and 66.2% (58.6-73.8%) for PCV13 vaccine coverage. CONCLUSIONS: The prevalence of nasopharyngeal carriage among children was high in China. PCV7 immunization was found to be associated with reduction of nasopharyngeal colonization of S. pneumoniae. Conjugate vaccination coverage was slightly affected by the introduction of PCV7 into China because of low vaccination rate. The government should implement timely adjusted conjugate vaccination strategies based on our findings.

Epidemiology of and risk factors for neonatal candidemia at a tertiary care hospital in western China.

BACKGROUND: The prevalence and clinical characteristics of neonatal candidemia are poorly understood in western China. The aim of our study was to evaluate the epidemiological features of neonatal candidemia in the Liuzhou Maternity and Child Healthcare Hospital. METHODS: A retrospective case-control study was conducted between January 2012 and November 2015. Electronic databases were reviewed and data on Candida species were isolated from blood cultures and candidemia incidence, risk factors, and mortality were extracted. Univariate and multivariate logistic regression analysis were performed to identify risk factors associated with candidemia. RESULTS: During the 4-year period, candidemia was identified in 69 newborns, for an incidence rate of 13.6 per 1000 admissions. Prolonged antibiotic therapy duration [odds ratio (OR), 95% confidence incidence (95% CI) = 1.06, 1.01-1.10], total parenteral nutrition [OR, 95% CI = 6.03, 2.10-17.30] and neurodevelopmental impairment (OR, 95% CI = 7.34, 1.18-45.80) were all associated with increased odds of candidemia development in infants (P value was 0.010, 0.001, 0.033, respectively). The overall mortality rate was 7.2% in the candidemia group. CONCLUSIONS: Prolonged duration of antibiotic therapy, presence of total parenteral nutrition and neurodevelopmental impairment were the major risk factors associated with neonatal candidemia. This study highlights the importance of the early detection, diagnosis and treatment of neonatal candidemia.

Low complexity symmetric-coded based sphere decoding for low-rate polar codes.

The sphere decoding (SD) algorithm can provide (sub)optimal solutions with reduced computational complexity of maximum likelihood (ML) detection for multi-input multi-output (MIMO) communication systems. In this paper, we propose a novel low complexity symmetric-coded based SD algorithm for short polar codes with low rate. At the encoding stage, the first N/2 sub-channels transmit the frozen bits, while the information bits are selected from the latter N/2 sub-channels. Two symmetric codes are generated due to the mathematical structure of the generator matrix, which is well conditioned to the SD search. At the decoding stage, the presented SD algorithm computes the Euclidean distance value by the combined signals to estimate the latter N/2 input bits. Furthermore, the backtrack operation starts from the earlier [Formula: see text]-th bit, which can significantly reduce the average visited nodes (AVN). Simulation results show that, compared to the original SD algorithm, the presented variant of the SD algorithm can reduce the AVN to [Formula: see text] for the polar code P(64, 14) at SNR = 1  dB with a performance loss within 0.2 dB. The presented SD algorithm may find applications in MIMO systems where the complexity of the standar ML detection increases exponentially with the transmitting antennas.

Clinical Characteristics of 204 Children With Human Adenovirus Type 7 Pneumonia Identified by Whole Genome Sequencing in Liuzhou, China.

BACKGROUND: Clinical knowledge of human adenovirus type 7 (HAdV-7) pneumonia in children remains limited. Moreover, predictors for disease severity are largely unknown. METHODS: This is a retrospective study of children hospitalized at Liuzhou Maternal and Child Health Hospital, China, with HAdV-7 pneumonia in 2018-2019. Demographics, clinical characteristics, laboratory results, and imaging data were collected. HAdV-7 was identified in plasma using whole genome sequencing, which yielded quantitative HAdV-7 sequence numbers. RESULTS: There were 204 children; 145 (71%) were <2 years of age. There were 68 children with severe pneumonia (SP) and 136 with nonsevere pneumonia (NSP). Up to 43% in SP group with respiratory failure (SP-RF) were <12 months of age. Median duration of fever before hospitalization was shorter in NSP group than SP groups (P < 0.01). Fourteen (6.9%) underwent mechanical ventilation. There was a significant difference in mean plasma HAdV-7 sequence numbers among SP-RF, SP without respiratory failure (SP-NRF), and NSP groups (2485 ± 165, 2034 ± 124, and 286 ± 35, respectively) (P < 0.01). In a logistic regression analysis, we found that elevated plasma HAdV-7 sequence numbers significantly increased the risk of severe HAdV-7 pneumonia (OR 1.80, 95% confidence interval: 1.59-2.60, P < 0.01) after adjusting for age, fever duration, platelet counts, and serum lactate dehydrogenase levels. CONCLUSIONS: Over two-thirds of children hospitalized with HAdV-7 pneumonia were <2 years of age. Approximately 40% of those with SP associated with respiratory failure were <12 months of age. Those with SP exhibited higher plasma HAdV-7 sequence numbers. Thus, plasma HAdV-7 sequence numbers have a potential in predicting severity of HAdV-7 pneumonia in children.

The Predictive Value of Infant-Specific Preoperative Pulmonary Function Tests in Postoperative Pulmonary Complications in Infants with Congenital Heart Diseases.

BACKGROUND AND OBJECTIVE: To investigate the relationship between infant-specific preoperative pulmonary function tests (PFTs) and postoperative pulmonary complications (PPCs) in infants with congenital heart diseases (CHDs). METHODS: Patients of 1-3 years of age who received surgical treatment for CHDs from January 1st, 2009, to December 31st, 2017, were retrieved. Records of preoperative PFTs, methods of operation, anesthesia procedures, intraoperative vital signs, respiratory support modalities, and PPCs was retrieved and analyzed. RESULTS: 122 infants met the preset inclusion criteria, including 72 males and 50 females. There were 76 cases of thoracotomy and 46 cases of cardiac catheterization. The overall incidence of PPCs was 15.6%, including 19.7% after thoracotomy and 8.7% after cardiac catheterization, respectively (p > 0.05). The incidence of PPCs was 35.4% or 2.7% in infants with a rapid or a normal respiratory rate, respectively; 42.1% or 3.6% in infants with an abnormal or a normal time to reach peak tidal expiratory flow versus the total expiratory time (TPTEF/TE), respectively; 39.0% or 3.7% in infants with an abnormal or a normal volume to peak expiratory flow versus the total expiratory volume (VPEF/VE), respectively; and 46.9% or 4.4% in infants with a decreased or a normal lung compliance, respectively (p < 0.01 in all comparisons). CONCLUSIONS: The preoperative abnormal changes in respiratory rate, TPTEF/TE, VPEF/VE, and lung compliance are indicative of the risk of PPCs.

Growth of HIV-Exposed Infants in Southwest China: A Comparative Study.

Objectives. Prevention of mother-to-child HIV transmission has been globally successful leading to a decline in HIV-infected infants. Thus, the number of HIV-exposed, but uninfected, infants is increasing. As growth is an important indicator of child health, this study aimed to evaluate growth parameters of HIV-exposed Chinese infants. Methods. A prospective study was conducted among HIV-exposed (HIV-infected and uninfected) infants born during 2007 to 2015 in Liuzhou, China. Their weight and length were assessed longitudinally from birth to 18 months of age and compared with HIV-unexposed, uninfected (HUU) infants from the same region. Results. There were 467 HIV-exposed infants. Four percent of infants were HIV-infected. The mean weight-for-age (WAZ) and length-for-age (LAZ) z scores of HIV-infected infants were significantly lower than those of HIV-exposed but uninfected (HEU) infants during 9 to 18 months and 12 to 18 months of age, respectively. Additionally, the mean WAZ and LAZ scores of HIV-infected infants were significantly lower than HUU infants during the first 12 months and 18 months of life, respectively. The mean WAZ and LAZ scores of HEU infants were significantly lower than HUU infants during the first 12 months and 6 months of life, respectively. HEU infants also had a lower mean weight-for-length z score than HUU infants during the first 6 months. Conclusion. We demonstrated poor growth among HIV-exposed Chinese infants, including HIV-uninfected, compared with HUU infants. The results emphasize the need for nutritional monitoring and interventions for HIV-exposed infants regardless of HIV infection status. Research is needed on long-term growth trajectories and factors affecting growth of HIV-exposed infants in China.

Pulmonary Function Testing in Pediatric Pneumonia Patients With Wheezing Younger Than 3 Years of Age.

Background. Wheezing symptoms are one of the risk factors in young pneumonia patients that often leads to asthma development. Infant pulmonary function test (iPFT) is potentially a useful tool to help identify and manage these high-risk pneumonia patients. Methods. To examine whether patients with wheezing symptoms are more likely to have poorer pulmonary function and treatment outcomes, and also to explore the clinical benefit of iPFT in young pneumonia patients, we conducted a retrospective analysis of 1005 pneumonia inpatients <3 years of age who had undergone iPFT testing in 2016 at Liuzhou Maternity and Child Healthcare Hospital in Guang-Xi, China. Results. We identified from the hospital database 505 pneumonia patients who presented with wheezing and 500 without wheezing. Univariate analysis showed that wheezing symptoms, viral infection, age <1 year, female gender, and prematurity were significantly associated with poorer iPFT results. After adjusting for confounders, patients with wheezing showed significantly poorer pulmonary function. Patients with wheezing had longer length of stay (7.9 ± 3.9 days vs 6.5 ± 2.6 days; P < .001) and lower percent with no residual clinical symptoms at discharge (58% vs 98%; P < .001) when compared with those of non-wheezing patients. In addition, 81% of patients with viral infection as compared with 43% of patients with nonviral infection presented with wheezing symptoms (P < .001). Conclusion. Wheezing symptoms were associated with poorer iPFT measures and treatment outcomes for pneumonia inpatients <3 years of age. Patients with wheezing had poorer treatment outcomes. iPFT can be useful in assessing and monitoring young patients with high risk of developing asthma or chronic lung disease later in life.

Risk factors and clinical analysis of candidemia in very-low-birth-weight neonates.

BACKGROUND: Candidemia is the third leading cause of morbidity and mortality in preterm or very-low-birth-weight infants. The incidence and risk factors of candidemia in this population are poorly known in western China. METHODS: A case-control retrospective study of candidemia was conducted from January 2012-November 2015 in the Liuzhou Maternity and Child Healthcare Hospital. Data were analyzed by univariate analysis and multivariate logistic regression. RESULTS: Forty-eight confirmed cases of candidemia were identified during the study period, indicating an incidence of 106.9 per 1,000 admissions of very-low-birth-weight infants. Candida albicans was the most common pathogen and was isolated in 39.6% of infants with candidemia. The mortality rate of the case group was 10.4% versus 2.1% in the control group (P = .128). The multivariable logistic regression model identified that carbapenem use (odds ratio [OR], 11.39; 95% confidence interval [CI], 3.28-39.54), total parenteral nutrition (OR, 10.16; 95% CI, 2.25-45.94), and prolonged hospitalization (OR, 1.04; 95% CI, 1.01-1.07) were all associated with the risk of developing neonatal candidemia. CONCLUSION: Very-low-birth-weight infants are at a significantly high risk of developing candidemia. The local neonatal intensive care unit management teams should effectively focus on decreasing the overall use of carbapenems, improving catheter care, removing catheters early, and shortening hospitalizations to reduce the incidence of candidemia.