Zhenjiang Yao

Healthcare Associated Infections of Methicillin-Resistant Staphylococcus aureus: A Case-Control-Control Study

Background Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most widespread and dangerous pathogens in healthcare settings. We carried out this case-control-control study at a tertiary care hospital in Guangzhou, China, to examine the antimicrobial susceptibility patterns, risk factors and clinical outcomes of MRSA infections. Methods A total of 57 MRSA patients, 116 methicillin-susceptible Staphylococcus aureus (MSSA) patients and 102 S. aureus negative patients were included in this study. We applied the disk diffusion method to compare the antimicrobial susceptibilities of 18 antibiotics between MRSA and MSSA isolates. Risk factors of MRSA infections were evaluated using univariate and multivariate logistic regression models. We used Cox proportional hazards models and logistic regression analysis to assess the hospital stay duration and fatality for patients with MRSA infections. Results The MRSA group had significantly higher resistance rates for most drugs tested compared with the MSSA group. Using MSSA patients as controls, the following independent risk factors of MRSA infections were identified: 3 or more prior hospitalizations (OR 2.8, 95% CI 1.3–5.8, P = 0.007), chronic obstructive pulmonary disease (OR 5.9, 95% CI 1.7–20.7, P = 0.006), and use of a respirator (OR 3.6, 95% CI 1.0–12.9, P = 0.046). With the S. aureus negative patients as controls, use of a respirator (OR 3.8, 95% CI 1.0–13.9, P = 0.047) and tracheal intubation (OR 8.2, 95% CI 1.5–45.1, P = 0.016) were significant risk factors for MRSA infections. MRSA patients had a longer hospital stay duration and higher fatality in comparison with those in the two control groups. Conclusions MRSA infections substantially increase hospital stay duration and fatality. Thus, MRSA infections are serious issues in this healthcare setting and should receive more attention from clinicians.

Construction and characterization of an anti‐asialoglycoprotein receptor single‐chain variable‐fragment‐targeted melittin

Antibody–therapeutic agent conjugation to be delivered specifically to tumor cells is required for many target‐based therapeutic strategies. In the present study, a recombinant immunotoxin was constructed by which melittin was fused to an anti‐asialoglycoprotein receptor (ASGPR) single‐chain variable fragment antibody (C1), and targeting ability and cytolytic efficacy of the fusion protein were studied. Our results suggested that the recombinant 29.4 kDa protein C1M was expressed in Escherichia coli as a soluble style. Binding of C1M to the surface of hepatocellular carcinoma (HCC) cells was confirmed by both immunohistochemistry and flow cytometry assays. C1M kept the hemolytic activity of melittin and exhibited cytolytic capacity to HepG2 cells at a concentration of 1.5 µg/mL, under which erythrocytes would not be lysed. The effects were greatly inhibited by coadministration with asialoorosomucoid, a natural ligand for ASGPR. These results suggested that C1M conferred targeting and ASGPR‐specific cytotoxicity to HCC cells. This work makes it possible to further investigate its antihepatoma efficacy in vivo.

Livestock-associated methicillin and multidrug resistant S. aureus in humans is associated with occupational pig contact, not pet contact.

This study aimed to explore the association of livestock-associated S. aureus with occupational pig contact and pet contact. In this cross-sectional study, 1,422 participants (including 244 pig workers, 200 pet-owning workers and 978 control workers) responded to a questionnaire and provided a nasal swab for S. aureus analysis. Resulting isolates were tested for antibiotic susceptibility, the immune evasion cluster (IEC) genes, and multilocus sequence type. Compared with controls, the pig workers demonstrated a greater prevalence of multidrug-resistant S. aureus (MDRSA) [prevalence ratio (PR) = 3.38; 95% CI: 2.07–5.53] and methicillin-resistant S. aureus (MRSA) (PR = 7.42; 95% CI: 3.71–14.83), but the prevalence of MDRSA and MRSA was similar in pet-owning workers and controls. There was a positive relation of frequency of pig contact with prevalence of MDRSA and MRSA carriage. Only pig workers carried MDRSA CC9 (16 isolates) and MRSA CC9 (16 isolates), and all of these isolates were tetracycline resistant and absent of IEC genes. These findings suggest that livestock-associated MRSA and MDRSA(CC9, IEC-negative, tetracycline-resistant) in humans is associated with occupational pig contact, not pet contact, and support growing concern about antibiotics use in pig farms and raising questions about the potential for occupational exposure to opportunistic S. aureus.

Second-hand smoke exposure in different types of venues: before and after the implementation of smoke-free legislation in Guangzhou, China

Objectives Smoke-free legislation was implemented in Guangzhou on 1 September 2010. However, the smoke-free policy did not cover all indoor areas and smoking rooms can be set in some public places. This study aimed to assess changes in self-reported second-hand smoke (SHS) exposure in different types of venues and in homes, in order to evaluate the effectiveness of smoke-free legislation. Methods/design A repeated cross-sectional survey of representative participants was conducted in Guangzhou before and after the smoke-free legislation. Logistic regression models were used to examine the effectiveness of smoke-free legislation. Main outcome measures Self-reported exposure to SHS,antitobacco advertisements and tobacco advertisements. Participants A total of 4900 participants before the ban and 5135 participants after the ban were selected using a multistage stratified design. Results In full smoking ban places, overall self-reported SHS exposure has declined significantly from 58.8% to 50.3% (p<0.05) with greater drops in cultural venues, government offices and commercial venues. The smoke-free policy did not alter SHS exposure in smokers’ homes (39.6% in 2009 vs 40.0% in 2011; p=0.454). Although a slight decrease in SHS exposure was observed in smoking rooms in hotels, workplaces, restaurants, cafes/bars/nightclubs and amusement parks, SHS continued to be high in those areas. The implementation of smoke-free legislation was accompanied by an increase in antitobacco advertisements. Conclusions SHS exposure declines more significantly in full smoking ban places than in partial smoking ban places. The smoke-free policy in public places does not lead to more SHS exposure in homes. Therefore, it is recommended that Guangzhou should implement a 100% smoke-free policy in all public places and workplaces in the future.

Alarming regional differences in prevalence and antimicrobial susceptibility of group B streptococci in pregnant women: A systematic review and meta-analysis

Group B streptococcus (GBS) is a leading cause of morbidity and mortality in infants. This study aimed to estimate the prevalence, antimicrobial susceptibility and serotype distribution of GBS isolates in pregnant women worldwide. Studies were identified by searching several English and Chinese electronic databases and reviewing relevant articles. Effect estimates were pooled using fixed- or random-effects models. Twenty-eight studies were included in this systematic review. The pooled prevalence of GBS carriage in pregnant women was 10%, being significantly lower in Asia (7%) compared with non-Asian countries (19%). Most of the GBS isolates were susceptible to penicillin, ampicillin and vancomycin. The pooled rates of resistance to erythromycin and clindamycin were 25% and 27%, respectively, and were notably higher in Asia compared with non-Asian countries. The pooled rate of resistance to tetracycline was 73%, with similar high levels in Asia and non-Asian countries. The most prevalent serotypes of GBS isolates were serotypes III, V and Ia. These findings suggest that penicillin is still the first choice for intrapartum prophylaxis of GBS diseases and support growing concern about antibiotic use (especially erythromycin and clindamycin) in Asia.

Non-hospital environment contamination with Staphylococcus aureus and methicillin-resistant Staphylococcus aureus: proportion meta-analysis and features of antibiotic resistance and molecular genetics

BACKGROUND Staphylococcus aureus (S. aureus), including methicillin-resistant Staphylococcus aureus (MRSA), survives in dry conditions and can persist for long periods on surfaces touched by humans. Studies that estimate the proportions and characteristics of S. aureus and MRSA contamination in non-hospital environments are lacking. Therefore, we conducted a proportion meta-analysis and reviewed the features of antibiotic resistance and molecular genetics. METHODS Articles published between January 2005 and December 2015 that studied proportions of S. aureus and MRSA contamination in non-hospital environments were retrieved from the Medline database, Ovid database and Science Direct database. All statistics were analyzed by STATA 14.1. RESULTS Twenty-nine articles were included. The overall proportions of S. aureus and MRSA contamination were 41.1% (95%CI 29-54%) and 8.6% (95%CI 5-13%), respectively. The proportion of MRSA contamination increased over time. From the articles, the proportion of Panton-Valentine Leukociden (PVL) genes among MRSA isolates was 54.5%, and the proportion of the qac gene was 100.0%. Distribution of the multilocus sequence type (MLST) and pulsed-field gel electrophoresis (PFGE) of MRSA indicated that MRSA strains were from both hospitals and communities. CONCLUSION The overall proportions of S. aureus and MRSA contamination in non-hospital environments were high. The outcomes of antibiotic resistance and high proportions of PVL genes indicated that the antibiotic resistance of S. aureus and MRSA were notable. According to the different distributions of MLST and SCCmec of MRSA, we can infer that cross-circulation is within hospitals, communities, and livestock. The results also show that the risk from the MRSA strains was cross-transmitted among the population. High proportions of the qac gene of MRSA might indicate that current disinfection of MRSA has not been achieved, and it might be better to further identify the efficiency of the sterilization processes in a non-hospital environment so that relevant departments can take measures to improve disinfection of MRSA in non-hospital environments.

Three single nucleotide variants of the HDAC gene are associated with type 2 diabetes mellitus in a Chinese population: a community-based case-control study.

OBJECTIVES There are no data regarding the possible role of the single nucleotide polymorphism (SNP) of class I histone deacetylases (HDACs) in type 2 diabetes mellitus (DM). We designed this study to examine whether polymorphisms of HDACs can be implicated in that disease. METHODS A community-based, case-control study was conducted, with a total of 568 subjects (284 patients and 284 controls) enrolled. Four polymorphisms of HDAC1 (rs1741981) and HDAC3 (rs11741808, rs2547547, rs2530223) were examined by the use of TaqMan technology. RESULTS We found a significant association with risk of type 2 DM for three SNPs of HDAC3, including rs11741808 [odds ratio (OR)=0.53, 95% confidence interval (CI): 0.35-0.81], rs2547547 [OR=1.72, 95% CI: 1.13-2.64], and rs2530223 [OR=1.39; 95% CI: 1.01-1.91]. Subgroup analysis showed that BMI≥23kg/m(2), high triglyceride and high blood pressure, together with the rs11741808AG genotype, were associated with a significantly decreased risk for type 2 DM, with ORs of 0.50 (95% CI: 0.27-0.91), 0.38 (95% CI: 0.20-0.71) and 0.43 (95% CI: 0.24-0.76) compared with the AA genotype, respectively. In a population with normal total cholesterol, the AG genotype yielded a significantly decreased risk of type 2 DM risk, with an OR of 0.42 (95% CI: 0.25-0.70) when compared with the persons of the AA genotype. For rs2547547, in a population with normal total cholesterol and triglyceride, the AG genotype was associated with a significantly increased risk of type 2 DM, with ORs of 1.92 (95% CI: 1.17-3.15) and 2.24 (95% CI: 1.28-3.94) when compared with the population carrying the AA genotype. CONCLUSIONS The results suggest that variants of HDAC3 contribute to an increased prevalence of type 2 DM in the Chinese Han population.

Metro system in Guangzhou as a hazardous reservoir of methicillin-resistant Staphylococci: findings from a point-prevalence molecular epidemiologic study

Staphylococci are common causes of healthcare-associated and community-associated infections. However, limited data are available on the prevalence, phenotypes and molecular characteristics of Staphylococci in metro system around the world. 320 surface samples were collected from the Guangzhou metro system to isolate and characterize Staphylococci strains. Of the samples, 75.6% (242/320) were contaminated with Staphylococci. The Staphylococci isolates, especially the methicillin resistant isolates, were resistance to most of the antibiotics, with 79.8% (193/242) classified as multidrug resistant (MDR) strains. 8 strains of methicillin-resistant Staphylococcus aureus (MRSA) carried a range of staphylococcal cassette chromosome mec (SCCmec) types [I (1), II (3), III (2) and NT (2)]. Staphylococcus aureus isolates were classified into several ST types and showed possible cross transmissions of strains from various sources. All MRSA strains were positive for the qac gene, and only one methicillin-susceptible Staphylococci aureus (MSSA) strain was positive for the Panton-Valentine leukocidin (PVL) genes. This study demonstrated that environmental surfaces in the Guangzhou metro system may be a hazardous reservoir for transmission of Staphylococci to passengers. The resistance to antibiotics and disinfectants observed among isolates was also noteworthy.

Multidrug-resistant Pseudomonas aeruginosa infections pose growing threat to health care-associated infection control in the hospitals of Southern China: a case-control surveillance study

BACKGROUND Multidrug-resistant Pseudomonas aeruginosa (MDRPA) is one of the most common agents among health care-associated infections. There is a lack of data on the clinical features of MDRPA from Southern China. METHODS A case-control surveillance study of P aeruginosa was conducted based on surveillance from July 2008-December 2012, in 5 hospitals of Guangzhou, China. Data were analyzed by univariate analysis and multivariate logistic regression using Stata 13 (StataCorp, College Station, TX). RESULTS Of the 348 P aeruginosa strains, the prevalence of MDRPA was 54%, and it has increased over time. Isolates of P aeruginosa showed increased resistance to most antimicrobials during this time period. Independent risk factors were tracheal intubation insertion (odds ratio [OR], 2.21; 95% confidence interval [CI], 1.16-4.23; P = .02) and use of carbapenem (odds ratio [OR], 3.36; 95% confidence interval [CI], 1.75-6.47; P < .01). The distribution of MDRPA infections was uneven among the 5 hospitals (P = .01). Being infected with MDRPA strains resulted in longer duration of hospitalization (39 vs 24 days) and higher mortality (49% vs 20%). CONCLUSION The infections of MDRPA were severe issues. More stringent measures should be applied for those with independent predictors of MDRPA infections because they may induce adverse clinical outcomes.

Teicoplanin as an effective alternative to vancomycin for treatment of MRSA infection in Chinese population: a meta-analysis of randomized controlled trials.

Objective To evaluate whether teicoplanin could be an alternative to vancomycin for treatment of MRSA infection in Chinese population using a meta-analysis in randomized controlled trials. Methods The following databases were searched: Chinese Biomedical Literature database (CBM), Chinese Journal Full-text database (CNKI), Wanfang database, Medline database, Ovid database and Cochrane Library. Articles published from 2002 to 2013 that studied teicoplanin in comparison to vancomycin in the treatment of MRSA infected patients were collected. Overall effects, publishing bias analysis and sensitivity analysis on clinical cure rate, microbiologic eradication rate and adverse events rate were performed by using Review Manager 5.2 and Stata 11.0 softwares. Results Twelve articles met entry criteria. There was no statistically significant difference between the two groups regarding the clinical cure rate (risk ratio [RR], teicoplanin vs vancomycin, 0.94; 95% CI, 0.74∼1.19; P = 0.60), microbiological cure rate (risk ratio [RR], teicoplanin vs vancomycin, 0.99; 95% CI, 0.91∼1.07; P = 0.74) and adverse event rate (risk ratio [RR], teicoplanin vs vancomycin, 0.86; 95% CI, 0.40∼1.84; P = 0.70). Conclusions The meta-analysis results indicate that the two therapies are similar in both efficacy and safety, thus teicoplanin can act as an effective alternative to vancomycin for treating patients infected by MRSA.