Investigation of disinfection failure of flexible gastrointestinal endoscope due to Burkholderia cepacia contamination in irrigation tubing.

BACKGROUND AND AIMS: This study aims to identify the cause of disinfection failure of multiple flexible gastrointestinal endoscopes and to enhance the cleaning and disinfection procedures. METHODS: Samples from endoscopy devices, surrounding objects, cleaning water, automatic sterilizer, and integrated endoscopic washing workstation in a Digestive Endoscopy Center were collected and analyzed for microbial contamination and DNA/gene contents, between May and July 2021. RESULTS: The sample analysis revealed that the sink irrigation tubing of the washing workstation was contaminated with Burkholderia cepacia. After effective disinfection measures, the B. cepacia detection in the disinfected endoscope dropped from 13.23% to 0% (p=0.041). The presence of B. cepacia was confirmed through homology search and gene sequencing. CONCLUSIONS: The primary reason for endoscope disinfection failure is the contamination of the sink irrigation tubing by the B. cepacia bacteria. These findings emphasize the need for thorough cleaning of irrigation tubings in integrated endoscopic washing workstations, which is generally neglected in routine maintanance.

Successful Treatment of an AML Patient Infected with Hypervirulent ST463 Pseudomonas Aeruginosa Harboring Rare Carbapenem-Resistant Genes blaAFM-1 and blaKPC-2 Following Allogeneic Hematopoietic Stem Cell Transplantation.

Background: Carbapenem-resistant P. aeruginosa (CRPA) is a common hospital-acquired bacterium. It exhibits high resistance to many antibiotics, including ceftazidime/avibactam and cefteolozane/tazobactam. The presence of carbapenem-resistant genes and co-existence Klebsiella pneumoniae carbapenemase (KPC) and metallo-ß-lactamases (MBLs) further inactivated all ß-lactams. Understanding the resistance genes of CRPA can help in uncovering the resistance mechanism and guiding anti-infective treatment. Herein, we reported a case of perianal infection with hypervirulent ST463 Pseudomonas aeruginosa. Case Presentation: The case is a 32-year-old acute myeloid leukemia (AML) patient with fever and septic shock during hematopoietic stem cell transplantation (HSCT), and the pathogen was finally identified as a highly virulent sequence type 463 (ST463) P. aeruginosa harboring carbapenem-resistant genes blaAFM-1 and blaKPC-2, which was detected in the bloodstream and originated from a perianal infection. The strain was resistant to ceftazidime/avibactam but successfully treated with polymyxin B, surgical debridement, and granulocyte engraftment after HSCT. The AML was cured during the 19-month follow-up. Conclusion: This case emphasizes the importance of metagenomic next-generation sequencing (mNGS) and whole-genome sequencing (WGS) in identifying microbes with rare resistant genes, and managing CRPA, especially in immunocompromised patients. Polymyxin B may be the least resistant option.

[Clinical Characteristics and Survival Analysis of Carbapenem-Resistant Pseudomonas Aeruginosa Colonized or Infected Patients with Hematological Disorders].

OBJECTIVE: To observe the clinical characteristics and impact on mortality of carbapenem-resistant Pseudomonas aeruginosa (CRPA) colonized or infected patients with hematological disorders in order to provide evidence for the prevention and treatment of CRPA. METHODS: The patients who were colonized or infected with CRPA in the Department of Hematology of The First Affiliated Hospital of Zhejiang Chinese Medical University from January 2020 to March 2021 were selected as the research subjects, the clinical data such as hospitalization time, primary disease treatment regimen, granulocyte count, previous infection and antibiotic regimen of these patients were analyzed, meanwhile, antibiotic regimen and efficacy during CRPA infection, 30-day and long-term survival were also analyzed. RESULTS: A total of 59 patients were included in this study, and divided into CRPA infection group (43 cases) and CRPA colonization group (16 cases). Univariate logistic regression analysis showed that ECOG score (P =0.003), agranulocytosis (P <0.001), and exposure to upper than 3rd generations of cephalosporins and tigecycline within 30 days (P =0.035, P =0.017) were the high-risk factors for CRPA infection. Multivariate logistic regression analysis showed that ECOG score of 3/4 ( OR=10.815, 95%CI: 1.260-92.820, P =0.030) and agranulocytosis ( OR=13.82, 95%CI: 2.243-85.176, P =0.005) were independent risk factors for CRPA infection. There was a statistically significant difference in cumulative survival rate between CRPA colonization group and CRPA infection group ( χ2=14.134, P < 0.001). Kaplan-Meier survival analysis showed that the influencing factors of 30-day survival in patients with CRPA infection were agranulocytosis (P =0.022), soft tissue infection (P =0.03), and time of hospitalization before CRPA infection (P =0.041). Cox regression analysis showed that agranulocytosis was an independent risk factor affecting 30-day survival of patients with CRPA infection (HR=3.229, 95%CI :1.093-3.548, P =0.034). CONCLUSIONS: Patients with hematological disorders have high mortality and poor prognosis after CRPA infection. Bloodstream infection and soft tissue infection are the main causes of death. Patients with high suspicion of CRPA infection and high-risk should be treated as soon as possible.

Surveillance of Multidrug-Resistant Bacterial Infections in Non-Adult Patients - Zhejiang Province, China, 2014-2019.

INTRODUCTION: Antimicrobial resistance has become a major public health threat globally. The prevalence of multidrug-resistant (MDR) bacterial infections increased substantially among inpatients under 18 years of age in recent years. In Zhejiang Province, China, the trends of drug-resistance in non-adult patients from 2014 to 2019 were monitored, aiming to determine the variation patterns and epidemiological features of MDR strains. METHODS: Patient data were collected from the Annual Review of Hospital Infection Resistance Survey in Zhejiang Province, 2014-2019. Statistical analysis was performed to analyze the pattern of distribution of five key bacterial pathogens in different age groups, ward settings, and bloodstream infections. RESULTS: From 2014 to 2019, a total of 30,163 multidrug-resistant strains were identified among 212,252 clinical isolates. The prevalence of extended spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E), carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Acinetobacter baumannii, carbapenem-resistant Pseudomonas aeruginosa (CRPA), and methicillin-resistant Staphylococcus aureus (MRSA) were 40.6%, 2.3%, 14.7%, 9.0%, and 27.4%, respectively. The prevalence of these key pathogens was lower than that reported in the national surveillance system (China Antimicrobial Resistance Surveillance System and Infectious Diseases Surveillance of Pediatrics). The prevalence of ESBL-E and CRE decreased since 2015 but that of CRPA and MRSA increased from 2014 to 2018. CONCLUSIONS: Despite an overall decrease in the prevalence of drug-resistant bacteria in 2019, the rising prevalence of MRSA and CRPA still warrant much attention. Multidrug-resistant bacteria prevention and control strategies should be adjusted in a timely manner based on the surveillance results.

Pneumocystis jiroveci pneumonia, Nocardia brasiliensis, and Mycobacterium tuberculosis co-infection in a myasthenia gravis patient: A case report.

RATIONALE: Myasthenia gravis (MG) is an autoimmune disorder of the neuromuscular junctions that leads to fluctuating weakness and disabling fatigability. Due to difficulty in breathing caused by weakness of the respiratory muscles, patients with MG are more susceptible to pneumonia and other respiratory infections. As many patients with MG are given immunosuppressive therapy, this makes them more prone to infections. However, coinfection with 3 pathogens is very rare. PATIENT CONCERNS: Here, we report the case of a 41-year-old gentleman with MG who was receiving long-term steroid therapy. He presented with a cough with pale brown expectoration that occurred without obvious inducement, severe pain in the scapula, as well as swelling and weakness of both legs. Despite undergoing treatment, but his symptoms did not improve, prompting two additional hospital admissions over a period of several months. DIAGNOSIS: Bronchoscopy and bronchoalveolar lavage (BAL) were performed, revealing the presence of Pneumocystis jirovecii , Nocardia brasiliensis, and Mycobacterium tuberculosis (MTB). N brasiliensis was identified by positive modified acid-fast Kinyoun staining as well as a positive colony culture identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry from the BAL sample. MTB was confirmed using GeneXpert, and due to the limitations of the culture conditions, methenamine silver stain was used to confirm Pneumocystis jirovecii. Next-generation sequencing (NGS) assay of the BAL samples also confirmed these pathogens. INTERVENTIONS: The patient was transferred to a designated tuberculosis hospital and received anti-infective and anti-TB treatment. OUTCOMES: During treatment at the designated hospital, the patient developed gastrointestinal bleeding and impaired liver function. One month later, he developed multiple organ failure, consolidation of the left lower lung, and pan-drug resistant bacteremia. He refused further treatment and was discharged. CONCLUSION: In conclusion, physicians should be aware of the predisposition of MG patients to co-infections, especially patients with metabolic disorders, to avoid inadequate treatment and poor patient outcomes. Due to the limitations of culture conditions, NGS should be considered as a new technique for identifying pathogens.

Prevalence, risk factors and molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae in patients from Zhejiang, China, 2008-2018.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is emerging as a worldwide public health concern; however, the long-term molecular epidemiological surveillance of clinical CRKP in China is limited. We conducted a retrospective observational study (2008-2018) to assess the prevalence, susceptibility, risk factors and molecular epidemiology of clinical CRKP isolates. We found the prevalence of CRKP increased from 2.5%, 2008 to 15.8%, 2018. CRKP were significantly more frequent among hospitalized patients from ICU, and it was significantly more likely to be isolated from the capital city (Hangzhou) and the patients aged ≥60 years. Additionally, seasons and specimen types were associated with CRKP infections. The main CRKP sequence type (ST) was ST11, and bla KPC-2 was the most prevalent gene variant. Together these data reveal an increasing incidence and resistance trends among CRKP, especially the ST11-bla KPC-2-CRKP, in Zhejiang, during 2008-2018. Our findings are important for hospitals to limit its dissemination and optimize antibiotic administration.

Healthcare failure mode and effect analysis (HFMEA) for improving the qualification rate of disinfection quality monitoring process.

BACKGROUND: This study aimed to assess potential failure mode, implement countermeasures against risks and improve disinfection quality monitoring using healthcare failure mode and effect analysis (HFMEA). METHODS: Between July 2017 and March 2018, a multidisciplinary team was formed to conduct HFMEA and implement improvement interventions. Fourteen monitoring departments and seven monitoring items were involved. The qualification rate of monitoring process was used to evaluate the influence of HFMEA on the standardization monitoring management of disinfection quality. RESULTS: After HFMEA, the qualification rate of overall monitoring process of disinfection quality improved from 16.5% to 78.7% (P < 0.001), and the qualification rates of each monitoring step were all significantly improved. The qualification rate implemented by the clinical laboratory improved from 20.1% to 100.0% (P < 0.001). The qualification rate implemented by thirteen monitoring departments improved from 20.1% to 78.7% (P < 0.001), where seven reached 100%. Out of seven monitored items, three had the qualification rate of 100.0%, while the remaining four items showed significant rising in qualification rates (P < 0.001). CONCLUSION: HFMEA were helpful in improving the qualification rate of disinfection effect monitoring process.

Risk Factors for Carbapenem-Resistant Pseudomonas aeruginosa, Zhejiang Province, China.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a public health concern worldwide, but comprehensive analysis of risk factors for CRPA remains limited in China. We conducted a retrospective observational study of carbapenem resistance in 71,880 P. aeruginosa isolates collected in Zhejiang Province during 2015-2017. We analyzed risk factors for CRPA, including the type of clinical specimen; the year, season, and region in which it was collected; patient information, including age, whether they were an outpatient or inpatient, and whether inpatients were in the intensive care unit or general ward; and the level of hospital submitting isolates. We found CRPA was more prevalent among isolates from patients >60 years of age and in inpatients, especially in intensive care units. In addition, specimen types and seasons in which they were collected were associated with higher rates of CRPA. Our findings can help hospitals reduce the spread of P. aeruginosa and optimize antimicrobial drug use.

Epidemiology and risk factors of methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci infections in Zhejiang China from 2015 to 2017.

Background: Gram-positive bacteria are dangerous and challenging agents of infection due to their increasing resistance to antibiotics. We aim to analyse the epidemiology and risk factors of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) in Zhejiang China. Methods: Gram-positive bacteria (including S. aureus, Enterococcus faecalis and Enterococcus faecium) were collected from eighty-six hospitals of eleven cities in Zhejiang China from 2015 to 2017. The detection rates of MRSA and VRE infection were calculated for the non-duplicated isolate according to year, region, hospital level, patient age, specimen type and patient category. Meanwhile, the detected resistances of MRSA, E. faecalis and E. faecium to different antibiotics from 2015 to 2017 were compared. The risk factors and the differences in MRSA and VRE detection rates were compared using odds ratio (OR) with 95% confidence interval (95% CI) and Chi-square test respectively. Results: From 2015 to 2017, the detection rates of MRSA and VRE decreased gradually. The cities with the highest MRSA and VRE detection rates tended to be adjacent; for example, the neighbouring cities Hangzhou and Quzhou had simultaneously high rates of MRSA and VRE infection. Patients from IIIA hospital who were older than 75 years and in the intensive care unit (ICU) were most at risk. No vancomycin-resistant isolate was found in MRSA. Resistance of E. faecalis and E. faecium to vancomycin and linezolid decreased slightly and then maintained a low level. Conclusions: The detection rates of MRSA and VRE stayed at moderate and low levels during the three year period of this study, while local dissemination was found in MRSA and VRE isolates. Sustained surveillance is necessary to prevent the spread or clonal dissemination of drug-resistant strains in Zhejiang China.

Effect of pyrolysis temperature on characteristics of biochars derived from different feedstocks: A case study on ammonium adsorption capacity.

Physiochemical properties of biochars derived from different feedstock materials (rice straw, Phragmites communis, sawdust and egg shell) at different pyrolysis temperatures were analyzed, and adsorption capacities of ammonium (NH4+) on the biochars were investigated. The results show a clear effect of pyrolysis temperature on physicochemical properties of the biochars, including specific surface area, pH, and zeta potential. Consequently, biochars derived from the studied feedstocks at the selected temperatures exhibited different capacities to absorb NH4+. Highest NH4+ adsorption capacities were associated with biochars of rice straw (4.2 mg/g) and sawdust (3.3 mg/g) produced at 500 °C; at 300 °C observed NH4+ adsorption capacity was lower and highest figures were derived from the biochars of Phragmites communis (3.2 mg/g) and egg shell (2.2 mg/g). For all feedstocks, biochars produced at 700 °C showed the lowest NH4+ adsorption capacity. Our results suggest that zeta potential and C/H ratio, rather than surface area, are the most important factors in determining NH4+ sorption potential of biochars.

[Molecular mechanism of Shaofu Zhuyu decoction in treating endometriosis dysmenorrhea based on GPER2/MAPK/STAT1 axis].

The aim of this paper is to study the molecular mechanism of Shaofu Zhuyu decoction in treating dysmenorrhea of endometriosis based on GPER2/MAPK/STAT1 axis. In this study, HE staining was used to observe the pathological changes of the rats in each group. The levels of TNF-α and IL-6 were detected by ELISA assay. The mRNA expressions of neurotransmitter receptor (NK1) and GPER were detected by qPCR. The protein contents of MAPK and STAT1 were detected by Western blot. According to the results, compared with the model group, Shaofu Zhuyu decoction could significantly improve the inflammation of the ectopic uterine cavity tissue, decrease the contents of TNF-α and IL-6 in the uterine cavity, the mRNA expressions of NK1 and GPER, and the protein expressions of MAPK and STAT1. In conclusion, Shaofu Zhuyu decoction could effectively inhibit the expressions of GPER2, MAPK and STAT1, decrease the levels of TNF-α, IL-6 and NK1 mRNA and relieve the inflammatory pain in patients with endometriosis.

Complete genome sequence of human pathogen Kosakonia cowanii type strain 888-76T

ABSTRACT Kosakonia cowanii type strain 888-76T is a human pathogen which was originally isolated from blood as NIH group 42. In this study, we report the complete genome sequence of K. cowanii 888-76T. 888-76T has 1 chromosome and 2 plasmids with a total genome size of 4,857,567 bp and C+G 56.15%. This genome sequence will not only help us to understand the virulence features of K. cowanii 888-76T but also provide us the useful information for the study of evolution of Kosakonia genus.

Complete genome sequence of human pathogen Kosakonia cowanii type strain 888-76T.

Kosakonia cowanii type strain 888-76T is a human pathogen which was originally isolated from blood as NIH group 42. In this study, we report the complete genome sequence of K. cowanii 888-76T. 888-76T has 1 chromosome and 2 plasmids with a total genome size of 4,857,567bp and C+G 56.15%. This genome sequence will not only help us to understand the virulence features of K. cowanii 888-76T but also provide us the useful information for the study of evolution of Kosakonia genus.

Sequential enhanced cleaning eliminates multidrug-resistant organisms in general intensive care unit of a traditional Chinese medicine hospital.

PURPOSE: Effective cleaning of surfaces within hospital wards is necessary to reduce pathogen transmission. We investigated the roles of sequential enhanced cleaning by culturing pathogens from high-touch surfaces in a general intensive care unit. METHODS: A before-after controlled study was conducted during a 17-month period in the 25-bed general intensive care unit. The study comprised a baseline period (period 1) and 4 sequential tiered interventions: each patient zone was wiped with a single clean microfiber cloth daily (period 2), fluorescent markers and adenosine triphosphate assay were used to monitor and provide feedback on the effectiveness of cleaning (period 3), wiping a single patient zone with 3 clean microfiber cloths daily (period 4), and withdrawal of the feedback (period 5). RESULTS: Compared with period 1, the cultures of multidrug-resistant organisms from high-touch surfaces were reduced by 41.0% (prevalence ratio [OR] = 0.59, P < .001), 70.8% (OR = 0.29, P < .001), 82.6% (OR = 0.17, P < .001), and 70.8% (OR = 0.29, P < .0001) in the subsequent sequential interventions, respectively. CONCLUSION: Adoption of fluorescent markers and adenosine triphosphate bioluminescence reduced environmental contamination. Use of 3 cleaning cloths for 1 patient zone was more effective compared with a single cloth.

Draft Genome Sequence of Klebsiella pneumoniae Strain AS Isolated from Zhejiang Provincial Hospital of TCM, China.

Klebsiella pneumoniae is a Gram-negative, nonmotile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. Here we present draft genome assemblies of Klebsiella pneumoniae AS, which was isolated in China. The genomic information will provide a better understanding of the physiology, adaptation, and evolution of K. pneumoniae.

[Regulatory effect of Tripterygium wilfordii polycoride (TWP) towards TLR4/MyD88 independent pathway in TNBS/ethanol ulcerative colitis (UC) rat model].

In order to study the regulatory effect of Tripterygium wilfordii polycoride (TWP) towards TLR4/MyD88 independent pathway in TNBS/ethanol ulcerative colitis (UC) rat model, TNBS/ethanol enema was adopted to build TNBS/ethanol UC rat model. After the successful modeling procedure, 90 male Wistar rats are were divided into 6 groups, including namely normal group, model group, TWP low, middle, high dose groups (3, 6, 12 mg•kg⁻¹)and azathioprine (AZA) group (6 g•kg⁻¹), with 15 rats in each group. All rats in each group were administrated with corresponding medicines for 14 days. After 14 days of administration, corresponding colon tissues were taken for general and microscopic evaluation. Western blotting analysis and RT-PCR were adopted to test the mRNA and protein expressions of TLR4/MyD88 independent pathway-related molecules, namely TLR4, TRAM, TRIF, NF-κB and IFN-γ. The results showed that DAI, general and microscopic evaluations all indicated that TNBS/ethanol UC rat model was successful. TWP can improve UC-related clinical manifestation and heal colonic mucosa, which was equal to AZA. RT-PCR and WB results showed that the expression of TLR4/MyD88 independent pathway-related molecules in model group were significantly superior to that in normal group at either mRNA or protein level (P<0.01). Compared with model group, TWP can inhibit the expression of each node in TLR4/MyD88 independent pathway in a dose-dependent manner. The inhibitory effect of TWP with high dose towards the above molecules was inferior to that in model group at either mRNA or protein level (P<0.05). The inhibitory effect of TWP with high dose towards upstream molecules of TLR4/MyD88 independent pathway (TLR4, TRAM, TRIF, NF-κB) was slightly superior to AZA group at either mRNA or protein level. However, such inhibitory effect towards terminal inflammatory cytokines (IFN-γ) was inferior to AZA group at either mRNA or protein level. All the above differences had no statistical significance. Therefore, in TNBS/ethanol UC rat model, TLR4/MyD88 independent pathway took part in regulating inflammation. TWP exerted its anti-inflammation effect by inhibiting the expression of TLR4/MyD88 independent pathway in a dose-dependent manner.

Epidemiology and microbiology of nosocomial bloodstream infections: analysis of 482 cases from a retrospective surveillance study.

In many traditional Chinese medicine (TCM) hospitals, most patients are elderly with chronic diseases. Nosocomial bloodstream infections (nBSIs) are an important cause of morbidity and mortality. A retrospective surveillance study was performed to examine the epidemiology and microbiology of nBSIs in a TCM hospital from 2009 to 2011. A total of 482 patients with nBSIs were included in the study period. The incidence rate was 5.7/1000 admissions. Escherichia coli (25.5%) was the most common Gram-negative and coagulase-negative staphylococcus (CoNS) (14.1%) was the most common Gram-positive organism isolated. One-third of the E. coli and Klebsiella pneumoniae isolated from the nBSIs were the third-generation cephalosporin-resistant. Half of the Acinetobacter species isolates were resistant to imipenem. Of all the CoNS isolates, 90.7% were resistant to methicillin. Carbapenems and glycopeptide were the most frequently used for nBSI therapy. Only about one-third of patients (157/482) received appropriate empirical therapy. Septic shock, hemodialysis, Pitt bacteremia score >4, urinary tract infection, and appropriate empirical therapy were most strongly associated with 28-d mortality. The incidence of nBSIs was low in the TCM hospital but the proportion of nBSIs due to antibiotic-resistant organisms was high. A high Pitt bacteremia score was one of the most important risk factors for mortality in nBSIs. Therefore, the implementation of appropriate empirical therapy is crucial to improve the clinical outcome of nBSIs.

[Study on effects of Tripterygium wilfordii polycoride in resisting macrophage inflammation and regulating inflammation via TLR4/NF-κB].

To investigate the effect of Tripterygium wilfordii polycoride (TWP) on LPS-induced macrophage inflammatory response, particularly the inhibitory effect on inflammatory factors TNF-α and IL-1ß and the regulatory effect on inflammation via TLR4/NF-κB. The MTT method was adopted to test the effects of tested drugs, TWP, dexamethasone (DXM) and azathioprine (AZA) on cell growth to define the appropriate concentration. LPS was used to induce the inflammatory reaction in mouse RAW264. 7 cell lines. The Elisa kit was adopted to test the release level of TNF-α and IL-1ß. The Western blotting was applied to test the protein expressions of TNF-α and IL-1ß. The RT-PCR was adopted to test the expressions of TLR4 and NF-κB. According to the results, TWP could inhibit the release of macrophage inflammatory factors TNF-α and IL-1ß in a dose dependent manner. All of TWP groups showed a weaker efficacy than that of the DXM group. But the TWP high dose group revealed a better effect on TNF-α and equal effect on IL-1ß compared with the AZA group. TWP show an equal or better effect in down-regulating TLR4 and NF-κB p65 expressions in a dose dependent manner than DXM and AZA. In conclusion, TWP could inhibit TLR4 and NF-κB p65, which may be related to the down-regulation of TLR4 and NF-κB p65 receptor expressions.

Detection of the Smqnr quinolone protection gene and its prevalence in clinical isolates of Stenotrophomonas maltophilia in China.

The aim of this study was to detect novel variants of the Stenotrophomonas maltophilia Smqnr gene family and analyse the prevalence of Smqnr genes in clinical isolates of S. maltophilia in China. In total, 442 clinical isolates of S. maltophilia were collected from nine hospitals in four provinces in China. Antimicrobial susceptibility testing against six commonly used antibiotics was performed on these isolates. The sequences of the Smqnr genes amplified by PCR were aligned with those of known Smqnr genes in GenBank and an Smqnr database. The resistance rate against co-trimoxazole was highest at 48.6 %, followed by resistance rates against ceftazidime, chloramphenicol, ticarcillin/clavulanate and tigecycline at 28.7, 21.3, 19.0 and 16.1 %, respectively. The highest susceptibility was shown to levofloxacin, with a resistance rate of just 6.1 %. Smqnr genes were detected in 114 isolates, and comprised 11 previously identified genes and 20 new variants, bringing the total number of known Smqnr genes to 47. The 20 novel Smqnr genes were designated Smqnr28-47 and the encoded proteins showed only 1-12 amino acid differences among each other. The most common Smqnr genes in China were Smqnr8 and its variant Smqnr35 with prevalences of 17.5 % (20/114) and 13.2 % (15/114), respectively. Both the known and the novel Smqnr genes were discovered in both quinolone non-sensitive and sensitive isolates with similar frequency, suggesting that the Smqnr gene makes little contribution to quinolone resistance in this organism.