Mycoplasma pneumoniae (MP) is a leading cause of community-acquired pneumonia (CAP), accounting for 10–40% of cases in children. In China, the high prevalence of macrolide-resistant MP (MRMP) and recurrent MP epidemics place a significant burden on the healthcare system. Leveraging data from over 1.6 million cases, this study provides a comprehensive analysis of the epidemiological characteristics of MP across China. Seasonal patterns analysis revealed three distinct transmission zones in China. Transmission Zone 1 exhibited two annual epidemic peaks, while Zones 2 and 3 showed a single annual peak of distinct timings. Notably, winter travel to popular tourist destinations appears to influence MP infection patterns in China. Age- and sex- specific analysis indicated male newborns aged [0–1) years face a 1.67 times higher risk of MP infection compared to females. Conversely, females aged [23–38) years have a higher infection risk, likely due to their caregiving roles. The proportion of MRMP surged from 80.00% to 93.02% between July 2023 and May 2024, with a median growth rate of 10.21%. This rapid increase contrasts sharply with the modest 5.3% rise observed from 2011 to 2019, and we attribute this escalation in part to the growing prevalence of the T1-3R clade strain in China. These findings have important implications for the identification of high-risk population, place, and time for more targeted efforts of prevention and treatment. Furthermore, the rapidly increased proportion of MRMP in the 2023–2024 season raises a concerning signal regarding antibiotic use.

What is already known about this topic? The genus Anaplasma contains seven recognized bacterial species, mainly transmitted by tick bites. The two species, A. phagocytophilum and A. capra, are known commonly to cause diseases in humans. What is added by this report? Anaplasma bovis was initially thought to be only an animal agent until the first patient case was reported in 2019. This study investigated another two patients who became sick within one month in the same township and were infected with A. bovis in Anhui Province. What are the implications for public health practice? This study suggested that more A. bovis-infected patients may exist in this area and that patients with anaplasmosis require an early and specific diagnosis.

Legionnaires’ disease, caused by Legionella pneumophila , has been treated primarily with antibiotics. However, few reports have been published on antibiotic-resistant Legionella in China. Our aim was to determine the azithromycin resistance mechanism of L. pneumophila serogroup 1 in China.

The genus Legionella comprises over 60 species, which are important human pathogens. Secretion systems in Legionella pneumophila have been studied extensively because of the essential role of protein secretion in bacterial infection. However, there are few reports describing the secretion systems in non-L. pneumophila species. In this study, we analysed the distribution of secretion systems in L. pneumophila and 18 species of non-L. pneumophila based on whole genome sequences. A total of 74 whole genome sequences from 19 species of Legionella were analysed. Type II and IVB secretion systems were detected in all Legionella strains, but the type I secretion systems was restricted to L. pneumophila. The type IVA secretion system was randomly distributed among different species. Furthermore, we found the type VI secretion system in three non-L. pneumophila strains (Legionella cherrii DSM 19213, Legionella dumoffii Tex-KL, and Legionella gormanii ATCC 33297). In population structure analysis, L. pneumophila formed a conservative cluster and was located at the terminal of the evolutionary tree. At the same time, L. pneumophila, especially eight clone groups (named MCGG1-MCGG8), showed higher intracellular growth ability than non-L. pneumophila species. These results suggest that L. pneumophila has acquired additional secretion systems during evolution, resulting in increased pathogenicity.

Legionella pneumophila serogroup 1 causes Legionnaires' disease. Water systems contaminated with Legionella are the implicated sources of Legionnaires' disease. This study analyzed L. pneumophila serogroup 1 strains in China using sequence-based typing. Strains were isolated from cooling towers ( n = 96), hot springs ( n = 42), and potable water systems ( n = 26). Isolates from cooling towers, hot springs, and potable water systems were divided into 25 sequence types (STs; index of discrimination [IOD], 0.711), 19 STs (IOD, 0.934), and 3 STs (IOD, 0.151), respectively. The genetic variation among the potable water isolates was lower than that among cooling tower and hot spring isolates. ST1 was the predominant type, accounting for 49.4% of analyzed strains ( n = 81), followed by ST154. With the exception of two strains, all potable water isolates (92.3%) belonged to ST1. In contrast, 53.1% (51/96) and only 14.3% (6/42) of cooling tower and hot spring, respectively, isolates belonged to ST1. There were differences in the distributions of clone groups among the water sources. The comparisons among L. pneumophila strains isolated in China, Japan, and South Korea revealed that similar clones (ST1 complex and ST154 complex) exist in these countries. In conclusion, in China, STs had several unique allelic profiles, and ST1 was the most prevalent sequence type of environmental L. pneumophila serogroup 1 isolates, similar to its prevalence in Japan and South Korea.

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major cause of nosocomial infections worldwide. The transmission route of CRKP isolates within an outbreak is rarely described. This study aimed to reveal the molecular characteristics and transmission route of CRKP isolates within an outbreak of nosocomial infection. Methods: Collecting case information, active screening and targeted environmental monitoring were carried out. The antibiotic susceptibility, drug-resistant genes, molecular subtype and whole genome sequence of CRKP strains were analyzed. Results: Between October and December 2011, 26 CRKP isolates were collected from eight patients in a surgical intensive care unit and subsequent transfer wards of Beijing Tongren hospital, China. All 26 isolates harbored bla_KPC-2, bla_SHV-1, and bla_CTX-M-15 genes, had the same or similar pulsed-field gel electrophoresis patterns, and belonged to the sequence type 11 (ST11) clone. By comprehensive consideration of genomic and epidemiological information, a putative transmission map was constructed, including identifying one case as an independent event distinct from the other seven cases, and revealing two transmissions starting from the same case. Conclusions: This study provided the first report confirming an outbreak caused by K. pneumoniae ST11 clone co-harboring the bla_KPC-2, bla_CTX-M-15, and bla_SHV-1 genes, and suggested that comprehensive consideration of genomic and epidemiological data can yield a fine transmission map of an outbreak and facilitate the control of nosocomial transmission.