Serotype prevalence and antibiotic susceptibility patterns of pneumococcal isolates in Zunyi city, China

Molecular Characterization of Predominant Serotypes, Drug Resistance, and Virulence Genes of Streptococcus pneumoniae Isolates From East China

Streptococcus pneumoniae is a common diplococcus pathogen found worldwide. The characterization of predominant serotypes, drug resistance, and virulence genes of S. pneumoniae isolates prevailing in different areas and countries is clinically important for choice of antibiotics and improvement of vaccines. In this study, pneumonia (78.7%) and meningitis (37.0%) were the predominant diseases observed in the 282 (children) and 27 (adults) S. pneumoniae-infected patients (p < 0.05) from seven hospitals in different areas of East China. Of the 309 pneumococcal isolates, 90.3% were classified by PCR into 15 serotypes, with serotypes 19F (27.2%) and the 6A/B (19.1%) being most predominant (p < 0.05). Importantly, serotypes 15A and 15B/C combined for a total of 10.4% of the isolates, but these serotypes are not included in the 13-valent pneumococcal capsule conjugate vaccine used in China. Antimicrobial susceptibility analysis by the E-test showed that >95% of the 309 pneumococcal isolates were susceptible to moxifloxacin and levofloxacin, as well as 18.4, 85.8, and 81.6% of the isolates displayed susceptibility to penicillin, cefotaxime, and imipenem, respectively. A significant correlation between the prevalence of predominant serotypes and their penicillin resistance was observed (p < 0.05). In particular, >95% of all the pneumococcal isolates showed resistance to erythromycin and azithromycin. Of the nine detected virulence genes, the lytA, ply, hysA, and nanA were the most common with 95–100% positive rates in the 309 pneumococcal isolates, while the pavA and psaA genes displayed a significant correlation with pneumococcal bacteremia and meningitis (p < 0.05). Overall, our data suggested that the predominant serotypes, drug resistance, and virulence genes of the S. pneumoniae isolates prevailing in East China are distinct from those observed in other areas of China and adjacent countries.

Serotype Distribution and Characteristics of the Minimum Inhibitory Concentrations of Streptococcus pneumoniae Isolated from Pediatric Patients in Kunming, China

Streptococcus pneumoniae (S. pneumoniae) is the main conditional pathogen of acute respiratory infection in infants, children, and older adults worldwide. It was great significant to identify the epidemic characteristics of serotypes and antibiotic susceptibility for the prevention and treatment of S. pneumoniae diseases. This research assessed the serotype distribution and the minimum inhibitory concentrations (MICs) of S. pneumoniae isolated from pediatric patients to provide information on the epidemiology and antibiotic resistance of S. pneumoniae in Kunming, China. A total of 140 S. pneumoniae isolates were collected from pediatric patients at Kunming Children's Hospital from January 2016 to October 2017. Serotype identification was done by Quellung reaction and multiplex polymerase chain reaction. MICs were determined by E-test. 140 isolates distributed in 13 types of serotypes. The top-three prevalent serotypes were 19F, 19A, and 6B. The immunization coverage rate of 13-valent pneumococcal conjugate vaccine (PCV) was relatively higher and should be introduced into the vaccination program in the region. MIC50 of penicillin, ceftriaxone, and levofloxacin was 1 μg/mL. MIC50 for meropenem and vancomycin was 0.38 μg/mL. MIC90 of penicillin, ceftriaxone, and levofloxacin was 1.5 μg/mL and that of meropenem and vancomycin was 0.5 μg/mL. The MIC90 of erythromycin was > 256 μg/mL. In summary, S. pneumoniae had low resistance rates to penicillin, ceftriaxone, levofloxacin, vancomycin, and meropenem, and these antibiotics could be the first-line agents for children with pneumococcal infections in Kunming.

Prevalence and clinical significance of common respiratory pathogens in the upper respiratory tract of children with community-acquired pneumonia in Zunyi, China

PURPOSE

To estimate the prevalence of common respiratory pathogens among children with community-acquired pneumonia (CAP) in Zunyi City, Guizhou, China, and to assess whether the presence of common respiratory pathogens in patients is associated with disease severity.

PATIENTS AND METHODS

This retrospective study assessed the prevalence of common respiratory viruses and bacteria in the upper respiratory tract of among infants and children aged 1 month to 5 years hospitalized with radiologically confirmed CAP between April 2017 and March 2018. Direct immunofluorescence assay and bacterial culture were used to identify viruses and bacteria in the upper airway specimens, respectively. The association between severe CAP and the presence of pathogens was determined using multivariate logistic regression models.

RESULTS

Of the 685 patients enrolled, 583 cases had viral and/or bacterial pathogens detected, which included the presence of only viral pathogens, only bacterial pathogens, and mixed viral and bacterial pathogens in 34.3%, 29.7%, and 36.0% of cases, respectively. Respiratory syncytial virus (RSV) was the most common viral pathogen, with a prevalence rate of 39.9% (273/685). Haemophilus influenzae was the most commonly detected bacterial pathogen, with a prevalence rate of 15.3% (105/685). The presence of RSV (adjusted odds ratio [aOR], 1.9; 95% confidence interval [CI], 1.3-2.8) and Staphylococcus aureus (aOR, 13.7; 95% CI, 5.5-33.9) in children with CAP was associated with severe pneumonia.

CONCLUSIONS

In a cohort of Zunyi infants and children hospitalized with CAP, RSV was the most common pathogen.