Bacterial Epidemiology and Antimicrobial Resistance Profiles of Respiratory Specimens of Children with Pneumonia in Hainan, China

PURPOSE: To investigate the bacterial species and antimicrobial susceptibility of respiratory specimens of children with pneumonia in Hainan, China. METHODS: A total of 5017 specimens, including 4986 sputum samples, 19 bronchoalveolar lavage fluid samples and 12 tracheal tube tip samples from hospitalized children with pneumonia from April 1, 2021 to March 31, 2022 were studied. All the bacterial isolates were identified and confirmed with the VITEK 2 system. Antimicrobial susceptibility of all isolates was determined using the Kirby-Bauer method or the VITEK 2 Compact automatic system, following the breakpoints recommended by the Clinical and Laboratory Standards Institute. RESULTS: A total of 996 bacterial isolates were collected and classified into 24 species. The top 10 most frequent species were Haemophilus influenzae (356 isolates, 35.7%), Streptococcus pneumoniae (128, 12.9%), Moraxella catarrhalis (114, 11.5%), Escherichia coli (89, 8.9%), Staphylococcus aureus (89, 8.9%), Klebsiella pneumoniae (82, 8.2%), Acinetobacter baumannii (31, 3.1%), Pseudomonas aeruginosa (28, 2.8%), Enterobacter cloacae (18, 1.8%), and Streptococcus agalactiae (13, 1.3%). 70.5% strains had the resistant (R) and/or intermediate (I) phenotypes to at least one of the tested drugs, with a large proportion (54.6%) showing resistance to two or more commonly used antibiotics. In addition, 60.5% (69/114) of M. catarrhalis strains and 42.9% (153/356) of H. influenzae strains produced β-lactamases while 19.1% (17/89) E. coli and 6.1% (5/82) K. pneumoniae strains produced extended-spectrum β-lactamases. CONCLUSION: A diversity of pathogenic bacteria were isolated from the respiratory tract of children with pneumonia in Hainan, China. High-frequency resistance to first-line antimicrobial drugs was observed in Gram-negative and Gram-positive bacteria, including 544 isolates resistant to at least two antibiotics. Rapid identification and susceptibility testing should be implemented for children with bacterial pneumonia in Hainan before drug treatment is recommended.