Molecular epidemiology and change trend of methicillin-resistant Staphylococcus aureus from invasive infections of a hospital in Hangzhou from 2012 to 2018.

The disease caused by methicillin-resistant Staphylococcus aureus (MRSA) is a global public health challenge that threatens society and patients seriously. Therefore, the molecular epidemiology and change trend of MRSA is essential for the control and treatment of diseases caused by the pathogen in their regions. To explore molecular epidemiology of MRSA in Hangzhou, we collected 162 MRSA isolates from 2012 to 2018, conducted the antimicrobial susceptibility and used polymerase chain reaction(PCR) to test the molecular typing including multilocus sequence typing (MLST), staphylococcal chromosome cassette mec (SCCmec), staphylococcal protein A (spa A) and Panton-Valentine leucocidin (PVL). All the strains was divided into community-associated MRSA (CA-MRSA) or hospital-associated MRSA (HA-MRSA). 162 MRSA isolates were divided into 16 STs and 30 spa types. The major ST type was ST5 (96/162, 59.3%) and the predominant spa type was t311 (83/162, 51.2%). Five SCCmec types were found and the most common SCCmec type was type II (101/162, 61.7%). ST5-II-t311 was the predominant MRSA clone. And the prevalence of ST5 MRSA gradually declined from 2014 to 2018 but the prevalence of ST59 MRSA significantly increased. At the same time, livestock-associated methicillin-resistant Staphylococcus aureus(LA-MRSA) ST398 and ST9 were detected. Twenty-eight isolates were PVL gene positive (28/162, 17.3%). The most prevalent PVL-positive clone was ST59-IVa-t437. Comparing with HA-MRSA, CA-MRSA had a lower probability of ST5 (9.1% vs 67.1%, P=0.000) but a higher probability of ST59 (63.6% vs 11.4%, P=0.000), not only that, it was more likely to carrying PVL-positive gene (36.4% vs 14.3%, P=0.028). In summary, the molecular types of MRSA were getting complex over time. ST5-II-t311 was the predominant clone of MRSA isolate with a downward incidence from 2014 to 2018. ST59 MRSA strains, which is thought community related strain are spreading into hospitals and has an upward incidence from 2014 to 2018.

Comparison of clinical and microbiological characteristics of community-acquired hypervirulent Klebsiella pneumoniae liver abscess in diabetic and non-diabetic patients.

Invasive infection caused by hypervirulent Klebsiella pneumoniae (HvKP) has been reported worldwide. Most of the patients are community population, related to diabetes mellitus (DM), chronic liver disease and other basic diseases, which prone to systemic migratory infection. In this study, we collected 377 patients with community acquired Klebsiella pneumoniae liver abscess in our hospital from January 2013 to December 2018, 65.8% of whom were male, and 49.6% had DM. Patients with DM are prone to eye and central nervous system (CNS) infection, which need continuous local abscess drainage during treatment. Among them, patients with poor blood glucose control have a higher rate of blood stream infections (BSI). 219 strains of HvKP were obtained, with K1/K2 Serotype accounted for 81.7%. The incidence of BSI in K2 patients was higher than that in K1 patients. The PCR results indicate that the carrying rate of virulence genes (rmpA、areo、kfu、allS、iroN、magA、uge、wcaG) in K1/K2 type strains is significantly higher than that in non K1/K2 type strains. ST23 and ST65 are the most common multilocus sequence typing (MLST), which belong to K1 and K2 Serotype respectively. All of HvKP strains showed high sensitivity to commonly used clinical antibiotics other than ampicillin, with 54.3% of the strains exhibiting high viscosity characteristics. Meanwhile, 35 classic Klebsiella pneumoniae (cKP) strains were collected, and their serum typing is mainly non K1/K2. The carrying rate of virulence genes and viscosity degree in HvKP are significantly higher than those in cKP. Primary liver abscess caused by HvKP is prone to multiple tissue and organ infections, but it shows higher sensitivity to most commonly used antibiotics in clinical practice except for ampicillin. After effective treatment, the overall prognosis of patients is better. This study analyzes the pathogenic characteristics of HvKP and elaborates on the clinical characteristics of patients, which can provide reference for clinical and scientific research work.

Pharmacokinetic study of single and multiple oral dose administration of antofloxacin hydrochloride in healthy male volunteers / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A new fluroquinolone antibacterial agent, antofloxacin hydrochloride, developed in China, is an 8-NH(2) derivant of levofloxacin. The purpose of the study was to evaluate the pharmacokinetic characteristics of single and multiple oral doses of antofloxacin hydrochloride in Chinese healthy male volunteers.</p><p><b>METHODS</b>An open-label, non-randomized, single and multiple dose clinical trial was conducted. In single dose study, 12 subjects took 200 mg antofloxacin hydrochloride. In multiple dose study, 12 subjects took antofloxacin hydrochloride 400 mg once on day 1 and 200 mg once daily from day 2 to day 7. HPLC was used to assay the serum and urinary concentrations of antofloxacin.</p><p><b>RESULTS</b>In single dose study, the maximum concentration of drug in serum (C(max)), the time to reach C(max) (T(max)), and the area under the serum concentration-time curve (AUC (0-∞)) of antofloxacin were (1.89 ± 0.65) mg/L, (1.29 ± 0.26) hours, and (25.24 ± 7.26) mg×h(-1)×L(-1), respectively. Accumulating elimination rate of antoflocaxin from urine within 120 hours was 39.1%. In multiple dose study, blood concentration of antofloxiacin achieved stable state on day 2 after dosing. The minimum concentration drug in serum (C(min)), AUCss, mean concentration of drug in serum (C(av)), and degree of fluctuation (DF) were (0.73 ± 0.18) mg/L, (47.59 ± 7.85) mg×h(-1)×L(-1), (1.98 ± 0.33) mg/L, and 1.74 ± 0.60, respectively. On day 7 after dosing, T(max), C(max), and AUC (0-∞) was (1.14 ± 0.50) hours, (2.52 ± 0.38) mg/L, and (48.77 ± 8.44) mg×h(-1)×L(-1), respectively. Accumulating elimination rate of antofloxaxin from urine within 120 hours after the last dosing was 60.06%.</p><p><b>CONCLUSIONS</b>The regimen of 400 mg loading dose given on the first treatment day and then 200 mg dose once daily results in satisfactory serum drug concentration.</p>

Study on drug resistance and molecular epidemiology of Streptococcus pneumoniae isolated in Chongqing / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence and drug resistance of Streptococcus (S.) pneumoniae in patients infected in communities and molecular epidemiology with BOX-polymerase chain reaction (PCR) in Chongqing areas.</p><p><b>METHODS</b>A total of 680 clinical specimens from sputum and throat/nasal swabs were collected from patients seen from September 2000 to March 2001. Antibiotic susceptibility was determined by agar dilution test. BOX-PCR was used for molecular typing of S. pneumoniae.</p><p><b>RESULTS</b>A total of 39 isolates of S. pneumoniae were collected with the isolation rate of 5.7%. Of the 34 S. pneumoniae strains, two showed low-level resistance to penicillin (MIC 0.125 mg/L), one to levofloxacin, but many to macrolide and clindamycin (nearly 70%). All the strains were susceptible to beta-lactams and vancomycin. BOX-PCR typing demonstrated a high discriminatory potential and easy to be accurately analysed. 35 S. pneumoniae strains (include ATCC49619) were divided into 25 distinct types, representing 29 subtypes with A (n = 3) as the predominant type. 2 penicillin-resistant strains were shown to be different types.</p><p><b>CONCLUSION</b>Penicillin resistant rate of S. pneumoniae was low in Chongqing, but macrolide and clindamycin resistant strains were common while BOX-PCR typing was a suitable technique to type S. pneumoniae. No dominant antibiotic resistant strains were found in Chongqing.</p>

A study on the clinical and pathological efficacy of lamivudine in the treatment of chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate clinical effect, liver pathohistological changes (including pathology, HBV markers in liver tissue) in patients with chronic hepatitis B.</p><p><b>METHODS</b>70 patients of chronic hepatitis B were administered 100 mg Lamivudine orally daily for 1 year. The serum HBV-DNA, HBeAg/anti-HBe, hepatic chemistry and the hepatic fibrosis markers were studied. The needle biopsy of liver were performed in 35 patients before and after treatment and Knodell pathological score were done, HBsAg, HBcAg, alpha-SMA in liver tissue were examined by immunohistochemistry method.</p><p><b>RESULTS</b>After 1 year treatment the full response rate, partial response rate and no response rate were 23.72%, 69.49% and 6.78%, the patients in whom HBeAg seroconversion had higher base-line Alanine aminotransferase levels than the patients without seroconversion. Activity index of hepatic histology in 41.18% patients had a significant decrease. Histological assessment revealed that necrosis in portal area, pylenphlebitis and fibrosis were obviously alleviated. The liver immunohistochemistry examination showed HBcAg and alpha-SMA in liver decreased significantly in the patients with HBeAg seroconversion, no obvious alteration was observed in HBsAg expression. Lamivudine seems an effective compound with high safety and low side effect.</p><p><b>CONCLUSION</b>These results suggested that lamivudine (100mg/d) could suppress HBV-DNA replication, promote ALT normalization, accelerate HBeAg/anti-HBe seroconversion, improve the liver pathological changes, slow down the development of liver fibrosis</p>