Shigella flexneri serotype 2 variant (II:3,4,7,8) was isolated in 2008 and first reported in China in 2013. In the present study, epidemiological surveillance from 2003 to 2013 in China suggested that this serotype first appeared in Guangxi in 2003; it then emerged in Shanghai and Xinjiang in 2004 and in Henan in 2008. Of the 1813 S. flexneri isolates, 58 S. flexneri serotype 2 variant strains were identified. Serotype 2 variant has emerged as a prominent serotype in recent years, with 2a (32.6%), X variant (25.2%), 1a (9.4%), X (6.3%), 2b (5.4%), and 1b (3.6%). According to phenotypic and genotypic analysis, the serotype 2 variant originated from 2a to 2b. A higher antibiotic resistance rate was observed between 2009 and 2013 than that between 2003 and 2008. Among 22 cephalosporin-resistant isolates, blaTEM-1, blaOXA-1, blaCTX-3, blaCTX-14, and blaCTX-79 were detected. Among 22 fluoroquinolone-resistant isolates, a Ser80Ile mutation in parC was present in all of the isolates. Moreover, 21 isolates had three gyrA point mutations (Ser83Leu, His211Tyr, Asp87Asn, or Gly) and one isolate had two gyrA point mutations (Ser83Leu and His211Tyr). The prevalence of His211Tyr in the fluoroquinolone-resistant isolates is concerning, and the mutation was first reported in China. Besides, 22 isolates harbored the aac(6′)-Ib-cr gene, and two isolates harbored qnrS1. In view of the increased epidemic frequency and multidrug-resistant strain emergence, continuous surveillance will be needed to understand the actual disease burden and provide guidance for shigellosis.

We identified 2912 Shigella isolates from diarrhoeal patients in China during 2003-2013. The most common species was Shigella flexneri (55.3%), followed by Shigella sonnei (44.1%); however, S. sonnei is becoming increasingly prevalent. Among the S. flexneri isolates, serotypes 2a and X variant (-:7,8, E1037) were the two most prevalent serotypes, and serologically atypical isolates were also commonly identified. Overall, S. sonnei, S. flexneri 2a and S. flexneri X variant (-:7,8, E1037) accounted for 76.1% of all Shigella isolates, and their prevalence increased from 54.0% during 2003-2004 to 84.1% during 2011-2013. A change was observed in the serotype distribution of Shigella in China during this period, and we propose an ideal strategy to inform the development of a broadly effective Shigella vaccine candidate.

A 23-year-old male died of severe pneumonia and respiratory failure in a tertiary hospital in Beijing, and 4 out of 55 close contacts developed fever. Molecular analysis confirmed human adenovirus type 7 (HAdV7) as the causative agent. We highlight the importance of early diagnosis and treatment and proper transmission control of HAdV7. CASE REPORT Human adenovirus type 7 (HAdV7) infection is associated with acute respiratory disease syndrome, pharyngoconjunctival fever, pneumonia, and central nervous system disease (1-4). According to the last global survey, approximately one-fifth of all HAdV infections reported to the World Health Organization (WHO) were attributed to HAdV7 (5). HAdV7 outbreaks generally occur in settings with close living conditions, such as military barracks, hospital wards, and chronic care facilities (1,(6)(7)(8). In hospitals, HAdV has emerged as a nosocomial pathogen, and nosocomial outbreaks caused by HAdV7 with fatal cases have been reported worldwide (8-10). Although some prevention measurements have been carried out to control nosocomial transmission, questions regarding the efficacy of these programs persist, and the contribution of HAdV7 (and adenoviruses in general) to nosocomial infection is likely to be underestimated. Here, we report a case of HAdV7 infection associated with severe pneumonia and fatal acute lower respiratory disease and nosocomial transmission.The index case, a 23-year-old male in Wuhan City, Hubei Province, China, presented with a fever of approximately 39°C on 18 January 2014, but discontinuous treatment did not alleviate his symptoms. On 26 January, he was admitted to the emergency department of a tertiary hospital in Beijing. A routine blood test showed high neutrophil levels (71.4%) and elevated plasma C reactive protein (19 mg/ml), and chest radiographs revealed an increase of right lung markings. However, the use of cefoxitin sodium by injection did not prevent his condition from worsening, with symptoms including severe fever, cough, and phlegm. He was diagnosed with pneumonia and transferred to the respiratory department on 28 January. Six days later, he was transferred to an intensive care unit (ICU) because of lung consolidation, and he passed away on 5 February 2014.During his hospitalization, 4 of 55 close contacts developed fevers higher than 38.0°C, including a family member, a bedside clinician, and two patients in the same ward (Table 1 and Fig. 1). The initial secondary case (patient 1) was his cousin, a 19-year-old girl who visited the index case on 26 January for 30 min in the emergency department and on 2 February for 5 min in the respiration department. The distance between them was more than 2 meters, but neither wore a mask. She experienced a fever of 38.5°C on 3 February. Patient 2, a 29-year-old male with acute pancreatitis and a fatty liver, was admitted to the same ward of the emergency department on 27 January. He developed a fever on 3 February, and a chest X-ray showed pulmonary shadows. Patient 3, a bedside clinician of the inde...

From December 2012 to February 2013, two outbreaks of acute respiratory disease caused by HAdV-7 were reported in China. We investigated possible transmission links between these two seemingly unrelated outbreaks by integration of epidemiological and whole-genome sequencing (WGS) data. WGS analyses showed that the HAdV-7 isolates from the two outbreaks were genetically indistinguishable; however, a 12 bp deletion in the virus-associated RNA gene distinguished the outbreak isolates from other HAdV-7 isolates. Outbreak HAdV-7 isolates demonstrated increased viral replication compared to non-outbreak associated HAdV-7 isolate. Epidemiological data supported that the first outbreak was caused by introduction of the novel HAdV-7 virus by an infected recruit upon arrival at the training base. Nosocomial transmission by close contacts was the most likely source leading to onset of the second HAdV-7 outbreak, establishing the apparent transmission link between the outbreaks. Our findings imply that in-hospital contact investigations should be encouraged to reduce or interrupt further spread of infectious agents when treating outbreak cases, and WGS can provide useful information guiding infection-control interventions.

Shigella flexneri serotype 1b is among the most prominent serotypes in developing countries, followed by serotype 2a. However, only limited data is available on the global phenotypic and genotypic characteristics of S. flexneri 1b. In the present study, 40 S. flexneri 1b isolates from different regions of China were confirmed by serotyping and biochemical characterization. Antimicrobial susceptibility testing showed that 85% of these isolates were multidrug-resistant strains and antibiotic susceptibility profiles varied between geographical locations. Strains from Yunnan were far more resistant than those from Xinjiang, while only one strain from Shanghai was resistant to ceftazidime and aztreonam. Fifteen cephalosporin resistant isolates were identified in this study. ESBL genes (bla SHV, bla TEM, bla OXA, and bla CTX-M) and ampC genes (bla MOX, bla FOX, bla MIR(ACT-1), bla DHA, bla CIT and bla ACC) were subsequently detected among the 15 isolates. The results showed that these strains were positive only for bla TEM, bla OXA, bla CTX-M, intI1, and intI2. Furthermore, pulsed-field gel electrophoresis (PFGE) analysis showed that the 40 isolates formed different profiles, and the PFGE patterns of Xinjiang isolates were distinct from Yunnan and Shanghai isolates by one obvious, large, missing band. In summary, similarities in resistance patterns were observed in strains with the same PFGE pattern. Overall, the results supported the need for more prudent selection and use of antibiotics in China. We suggest that antibiotic susceptibility testing should be performed at the start of an outbreak, and antibiotic use should be restricted to severe Shigella cases, based on resistance pattern variations observed in different regions. The data obtained in the current study might help to develop a strategy for the treatment of infections caused by S. flexneri 1b in China.