Comparison of common human respiratory pathogens among hospitalized children aged ≤ 6 years in Hainan Island, China, during spring and early summer in 2019-2021.

The coronavirus disease 2019 (COVID-19) pandemic and related public health intervention measures have been reported to have resulted in the reduction of infections caused by influenza viruses and other common respiratory viruses. However, the influence may be varied in areas that have different ecological, economic, and social conditions. This study investigated the changing epidemiology of 8 common respiratory pathogens, including Influenza A (IFVA), Influenza B (IFVB), Respiratory syncytial virus (HRSV), rhinovirus (RV), Human metapneumovirus Adenovirus, Human bocavirus, and Mycoplasma pneumoniae, among hospitalized children during spring and early summer in 2019-2021 in two hospitals in Hainan Island, China, in the COVID-19 pandemic era. The results revealed a significant reduction in the prevalence of IFVA and IFVB in 2020 and 2021 than in 2019, whereas the prevalence of HRSV increased, and it became the dominant viral pathogen in 2021. RV was one of the leading pathogens in the 3 year period, where no significant difference was observed. Phylogenetic analysis revealed close relationships among the circulating respiratory viruses. Large scale studies are needed to study the changing epidemiology of seasonal respiratory viruses to inform responses to future respiratory virus pandemics.

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 ß-lactamases while 19.1% (17/89) E. coli and 6.1% (5/82) K. pneumoniae strains produced extended-spectrum ß-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.

Mixed genotypes of Orientia tsutsugamushi in conserved genes and a single immune-dominant tsa56 genotype discovered from a patient with scrub typhus in Hainan Island, China: a case report.

BACKGROUND: Orientia tsutsugamushi (O. tsutsugamushi), an obligate intracellular bacterium, is transmitted to humans through infected larval trombiculid mite bites, causing scrub typhus. Mixed genotypes of O. tsutsugamushi in canonical conserved genes were reported in 8-25% of blood samples from patients. Yet, there are few clinical descriptions of these mixed O. tsutsugamushi-infected patients. CASE PRESENTATION: We report a patient with scrub typhus complicated with pulmonary involvement and hepatic dysfunction, who carried mixed genotypes of the conserved genes but had a single immune-dominant 56-kDa type-specific antigen (tsa56) genotype. The patient was successfully recovered by doxycycline treatment. CONCLUSIONS: In this reported case, both patient's eschar and blood samples have repeatedly shown the same results, i.e., no variants were discovered in tsa56 gene that bears multiple hypervariable regions. Whereas the selected highly conserved genes were identified with up to 32 variants in a 2700 base-pair concatenated sequence. The prevalence, disease severity and mechanism of these single-tsa56-genotype mixed infections remain to be investigated on a large scale with more cases.

Osteomyelitis and Septic Arthritis Due to Burkholderia pseudomallei: A 10-Year Retrospective Melioidosis Study From South China.

Burkholderia pseudomallei is the causative agent of melioidosis, endemic mainly in tropical and subtropical areas. Its clinical manifestation is broad ranging from a localized skin lesion to a life-threatening systemic disease. Osteomyelitis and septic arthritis caused by B. pseudomallei are a rare, fatal illness, whose clinical features have not been illustrated in mainland China. Over 10 years (2010 to 2019), of 334 culture-confirmed melioidosis in Hainan province, China, 44 patients (13.2%) were confirmed to have osteomyelitis and septic arthritis through the combination of clinical features, imaging examination and microbiological culture. Herein, we summarized these 44 patients' clinical manifestations, demographical features, antibiotic treatment, and outcomes. Of them, osteomyelitis and septic arthritis accounted for 25 (56.8%) and 15 (34.1%), respectively, and 4 patients (9.1%) had both. The gender ratio of male/female was approximately 13.7:1; diabetes mellitus was the most common risk factor (38/44, 86.4%); imipenem and trimethoprim/sulfamethoxazole were the most frequently used antibiotics. Most B. pseudomallei strains were isolated from blood samples (41/44, 93.2%). After surgical handling, antibiotic treatment, or both, 9 patients died, with a mortality rate of 20.5%. In summary, in melioidosis endemic areas, for patients with both localized manifestations of joint and bone and a positive B. pseudomallei blood culture, increased awareness is required for melioidotic osteomyelitis and septic arthritis.