We describe the wide dissemination of CRAB CC22 in China. The close relatedness between CC22 and European clone II implies the probable global spread of CC22. It is inferred that ST22-CSAB evolves to ST22-CRAB through acquiring bla(OXA-23) as a determinative factor.

Secondary bacterial infections occurred in 13.9% (5 of 36) of critical ill patients with coronavirus disease 2019. All 5 patients had been admitted to intensive care unit and received mechanical ventilation before developing bacterial infection. Active surveillance of culture should be performed for critically ill patients. Prevention of nosocomial infection should to be taken seriously.

The beneficial effects of Bifidobacteria on health have been widely accepted. Patients with chronic liver disease have varying degrees of intestinal microflora imbalance with a decrease of total Bifidobacterial counts. Since different properties have been attributed to different Bifidobacterium species and there is no information available for the detailed changes in the genus Bifidobacterium in patients with chronic liver disease heretofore, it is meaningful to investigate the structure of this bacterium at the species level in these patients. The aim of this study was to characterize the composition of intestinal Bifidobacterium in patients with hepatitis B virus-induced chronic liver disease. Nested-PCR-based denaturing gradient gel electrophoresis (PCR-DGGE), clone library, and real-time quantitative PCR were performed on the fecal samples of 16 patients with chronic hepatitis B (CHB patients), 16 patients with hepatitis B virus-related cirrhosis (HBV cirrhotics), and 15 healthy subjects (Controls). Though there was no significant difference in the diversity among the three groups (P = 0.196), Bifidobacterium dentium seems to be specifically enhanced in patients as the PCR-DGGE profiles showed, which was further validated by clone library and real-time quantitative PCR. In contrast to the B. dentium, Bifidobacterium catenulatum/Bifidobacterium pseudocatenulatum were detected less frequently in the predominant profile and by quantitative PCR in HBV cirrhotics than in the controls, and the level of this species was also significantly different between these two groups (P = 0.023). Although having no quantitative difference among the three groups, Bifidobacterium longum was less commonly detected in HBV cirrhotics than in CHB patients and Controls by quantitative PCR (P = 0.011). Thus, the composition of intestinal Bifidobacterium was deeply altered in CHB and HBV cirrhotic patients with a shift from beneficial species to opportunistic pathogens. The results provide further insights into the dysbiosis of the intestinal microbiota in patients with hepatitis B virus-induced chronic liver disease and might potentially serve as guidance for the probiotics interventions of these diseases.

BackgroundKlebsiella pneumoniae has been the leading causative pathogen for adult bacterial meningitis in several Asian countries. The clinical and microbiological characteristics of K. pneumoniae meningitis in mainland China are still unknown.Materials and methodsThe clinical data of patients with K. pneumoniae meningitis from January 2011 to July 2017 in a tertiary hospital were retrospectively evaluated. The isolates were tested for antibiotic-resistance genes, virulence-associated genes, and molecular subtypes. Hyper-virulent K. pneumoniae (hvKP) was defined as the presence of pLVPK-like virulence plasmid.ResultsDuring the study period, a total of 48 patients with meningitis caused by K. pneumoniae were identified, accounting for 21.2% (48/226) of Gram-negative bacilli meningitis. Of the 44 available isolates, 65.9% (29/44) were carbapenem resistant, and all except one har-bored blaKPC-2. K64 was the most common serotype (n=13), followed by K47 (n=11) and K1 (n=5). The pLVPK-related genetic loci were found in about half of isolates (iutA: 56.8%, iucA: 56.8%, rmpA2:50.0%, rmpA: 43.2%, and iroN: 40.9%). Twenty-two strains carrying pLVPK-derived virulence plasmid were defined as hvKP. Notably, the coexistence of blaKPC-2-encoding plasmid and the pLVPK-derived virulence plasmid was detected in 15 strains (34.1%, 15/44), suggesting K. pneumoniae carbapenemase-2 (KPC-2)-producing hvKP. The proportion of KPC-2-producing hvKP by year increased remarkably from 0% (2011) to 71.4% (2017). Of the 15 KPC-2-producing hvKP strains, 80.0% (12/15) were assigned to sequence type 11 and 2 strains (13.3%) belonged to clonal complex 23. Most of the patients infected with KPC-2-producing hvKP had preceding postneurosurgical state (93.3%, 14/15) and severe pneumonia (73.3%, 11/15). All the cases (100%, 15/15) had fatal outcome.ConclusionThe high prevalence and mortality of K. pneumoniae, especially KPC-2-producing hvKP meningitis, in China should be of concern. The implementation of epidemiological surveillance and identification of an effective clinical treatment are paramount.

Hemoplasmas belong to Mycoplasmataceae (Mollicutes: Mycoplasmatales) and are able to infect a broad range of mammalian species. We investigated prevalence of hemotropic mycoplasma species in pig farms in the region of Zhejiang by a PCR scheme using universal primers targeting 16S rRNA and RNase P RNA gene (rnpB). Representative positive samples from different farms were selected for sequencing of 16S rRNA and the 219bp rnpB gene fragments for phylogenetic analysis. Sequencing analysis of PCR products from first samples identified a novel hemoplasma species present in several pig farms in the region with highest nucleotide identity of 92% to Candidatus Mycoplasma turicensis. A duplex PCR assay was then designed for differential detection of the novel hemoplasma from Mycoplasma parvum/M. suis in field samples. Of 324 blood samples from clinically healthy pigs, 26.5% was positive for this novel hemoplasma species and 50% positive for M. suis/M. parvum, indicating that the novel hemotropic mycoplasma species were of considerably high prevalence in Zhejiang province, China.

Background/ObjectiveSeveral studies have described the epidemiological distribution of bla OXA-58-harboring Acinetobacter baumannii in China. However, there is limited data concerning the replicon types of bla OXA-58-carrying plasmids and the genetic context surrounding bla OXA-58 in Acinetobacter spp. in China.Methodology/Principal FindingsTwelve non-duplicated bla OXA-58-harboring Acinetobacter spp. isolates were collected from six hospitals in five different cities between 2005 and 2010. The molecular epidemiology of the isolates was carried out using PFGE and multilocus sequence typing. Carbapenemase-encoding genes and plasmid replicase genes were identified by PCR. The genetic location of bla OXA-58 was analyzed using S1-nuclease method. Plasmid conjugation and electrotransformation were performed to evaluate the transferability of bla OXA-58-harboring plasmids. The genetic structure surrounding bla OXA-58 was determined by cloning experiments. The twelve isolates included two Acinetobacter pittii isolates (belong to one pulsotype), three Acinetobacter nosocomialis isolates (belong to two pulsotypes) and seven Acinetobacter baumannii isolates (belong to two pulsotypes/sequence types). A. baumannii ST91 was found to be a potential multidrug resistant risk clone carrying both bla OXA-58 and bla OXA-23. bla OXA-58 located on plasmids varied from ca. 52 kb to ca. 143 kb. All plasmids can be electrotransformed to A. baumannii recipient, but were untypeable by the current replicon typing scheme. A novel plasmid replicase named repAci10 was identified in bla OXA-58-harboring plasmids of two A. pittii isolates, three A. nosocomialis isolates and two A. baumannii isolates. Four kinds of genetic contexts of bla OXA-58 were identified. The transformants of plasmids with structure of IS6 family insertion sequence (ISOur1, IS1008 or IS15)-ΔISAba3-like element-bla OXA-58 displayed carbapenem nonsusceptible, while others with structure of intact ISAba3-like element-bla OXA-58 were carbapenem susceptible.ConclusionThe study revealed the unique features of bla OXA-58-carrying plasmids in Acinetobacter spp. in China, which were different from that of Acinetobacter spp. found in European countries. The diversity of the genetic contexts of bla OXA-58 contributed to various antibiotics resistance profiles.

Split-ring resonators are basic elements of metamaterials, which can induce a magnetic response in metallic nanosctructures. Tunability of such response up to the visible frequency range is still a challenge. Here we introduce the concept of the split-ball resonator and demonstrate the strong magnetic response in the visible for both gold and silver spherical plasmonic nanoparticles with nanometre scale cuts. We realize this concept experimentally by employing the laser-induced transfer method to produce near-perfect metallic spheres and helium ion beam milling to make cuts with the clean straight sidewalls and nanometre resolution. The magnetic resonance is observed at 600 nm in gold and at 565 nm in silver nanoparticles. This method can be applied to the structuring of arbitrary three-dimensional features on the surface of nanoscale resonators. It provides new ways for engineering hybrid resonant modes and ultra-high near-field enhancement.

BackgroundKlebsiella pneumoniae bloodstream infections (BSIs) occur with significant prevalence and high mortality worldwide. Antimicrobial resistance and virulence are two main factors participating in the pathogenicity of K. pneumoniae. Here we investigated the prevalence of blaKPC and virulence factors in K. pneumoniae isolated from patients with BSIs and their association with clinical outcome.MethodsThe clinical data of 285 K. pneumoniae BSI cases diagnosed from January 2013 to December 2015 in a Chinese university hospital were retrospectively evaluated. The “string test” was performed to identify hypermucoviscous K. pneumoniae (HMKP). blaKPC, rmpA, magA and serotype-specific genes were detected by PCR amplification. Finally, a Cox proportional hazards model was employed to determine the predictors of 14-day mortality.ResultsOf these isolates, the prevalence of blaKPC and rmpA were 33.3% (95/285) and 31.6% (90/285) respectively. 69 isolates (24.2%, 69/285) were HMKP. rmpA was strongly associated with HM phenotype. The KPC-producing KP and HMKP were almost non-overlapping and only three HMKP isolates harbored blaKPC. K1 (28, 40.6%) and K2 (22, 31.9%) were the most common serotypes in HMKP. 44.9% of HMKP BSIs had origin of biliary tract infection or liver abscess. The 14-day mortality was 100% in blaKPC+/HM+ subgroup (3/3), followed by blaKPC+/HM− (39/92, 42.4%), blaKPC−/HM+ (5/66, 7.6%) and blaKPC−/HM− (7/124, 5.6%). The 14-day cumulative survival was significantly different between blaKPC+ and blaKPC− subgroup (Log-rank p < 0.001) but almost equal between blaKPC−/HM+ and blaKPC−/HM− subgroup (Log-rank p = 0.578) under the condition of comparable illness severity between blaKPC−/HM+ and blaKPC−/HM− subgroup. Independent risk factors for 14-day mortality were Pitt bacteremia score (HR 1.24, CI 95% 1.13–1.36, p < 0.001), Charlson comorbidity index (HR 1.24, CI 95% 1.09–1.41, p = 0.001), septic shock (HR 2.61, CI 95% 1.28–5.35, p = 0.009) and blaKPC (HR 2.20, CI 95% 1.06–4.54, p = 0.034).ConclusionsMost of HMKP were antibiotic-susceptible and people infected received appropriate antimicrobial therapy, which may explain the favorable outcome of HMKP BSIs. The KPC-producing HMKP BSIs were scarce but life-threatening. blaKPC was valuable in predicting 14-day mortality.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3263-x) contains supplementary material, which is available to authorized users.