Dongxin Lin

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.

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.

A meta-analysis of the global prevalence rates of Staphylococcus aureus and methicillin-resistant S. aureus contamination of different raw meat products

Previous research has indicated that raw meats are frequently contaminated with Staphylococcus aureus , but data regarding the pooled prevalence rates of S. aureus and methicillin-resistant S. aureus (MRSA) contamination in different types of raw meat products (beef, chicken, and pork) and across different periods, regions, and purchase locations remain inconsistent. We systematically searched the PubMed, EMBASE, Ovid, Web of Science, and HighWire databases to identify studies published up to June 2016. The STROBE guidelines were used to assess the quality of the 39 studies included in this meta-analysis. We observed no significant differences in the pooled prevalence rates of S. aureus and MRSA contamination identified in various raw meat products, with overall pooled prevalence rates of 29.2% (95% confidence interval [CI], 22.8 to 35.9%) and 3.2% (95% CI, 1.8 to 4.9%) identified for the two contaminants, respectively. In the subgroup analyses, the prevalence of S. aureus contamination in chicken products was highest in Asian studies and significantly decreased over time worldwide. In European studies, the prevalence rates of S. aureus contamination in chicken and pork products were lower than those reported on other continents. The pooled prevalence rates of S. aureus contamination in chicken and pork products and MRSA contamination in beef and pork products were significantly higher in samples collected from retail sources than in samples collected from slaughterhouses and processing plants. These results highlight the need for good hygiene during transportation to and manipulation at retail outlets to reduce the risk of transmission of S. aureus and MRSA from meat products to humans.

A molecular epidemiological study of methicillin-resistant Staphylococci environmental contamination in railway stations and coach stations in Guangzhou of China

Methicillin‐resistant Staphylococcus aureus (MRSA) has caused a series of public health problems since it was first found in 1961. However, there are few research studies on the MRSA environmental contamination in railway stations and coach stations. Therefore, the aim of this study was to determine MRSA environmental contamination in public transport stations. Between December 2013 and January 2014, 380 surface samples from three railway stations (180) and four coach stations (200) in Guangzhou were collected to isolate and determine the prevalence and characteristics of Staphylococci strains. 39·21% of all samples were Staphylococci isolates, 1·58% of Staphylococci isolates were MRSA isolates, and 6·05% were methicillin‐susceptible S. aureus. The proportion of multidrug resistant among 149 Staphylococci isolates was 75·84%. None of MRSA isolates was identified with the Panton‐Valentine Leukocidin (PVL) genes, and one of them was identified with the qac gene. Four MRSA isolates were Staphylococcal Cassette Chromosome mec IVa, and the other two were nontypeable. Staphylococcus aureus isolates were classified into several sequence types (STs), and STs showed possible cross‐transmissions of isolates from various sources. Methicillin‐resistant Staphylococci contamination prevalence was high, and the environment of stations may be the vectors transmitting the Staphylococci to passengers.

A meta-analysis of the rates of Staphylococcus aureus and methicillin-resistant S aureus contamination on the surfaces of environmental objects that health care workers frequently touch

HighlightsThe overall pooled rate of Staphylococcus aureus contamination on the surface of environmental objects which health care workers frequently touched was high.There was a higher contamination rate of S aureus in developing countries.Contamination rate of S aureus was higher in recent publication years (2010‐2015). Background: Health care workers may potentially spread Staphylococcus aureus and methicillin‐resistant S aureus (MRSA) to patients by contaminated high‐touch items. We aimed to determine the pooled rates of S aureus and MRSA contamination and influencing factors. Methods: A literature search of the PubMed, ScienceDirect, Embase, Ovid, and Scopus databases was performed. Pooled contamination rates were determined using random effect models. Subgroup and meta‐regression analyses were conducted to identify factors potentially influencing the rates of S aureus and MRSA contamination. Sensitivity and publication bias analyses were performed. Results: Thirty‐eight studies were included in the meta‐analysis. The pooled contamination rates were 15.0% (95% confidence interval [CI], 9.8%‐21.1%) for S aureus and 5.0% (95% CI, 2.7%‐7.7%) for MRSA. The subgroup analyses indicated that the pooled rate of S aureus contamination was significantly higher for studies conducted in South America, in developing countries, and during 2010‐2015. The pooled rate of MRSA contamination was significantly higher for studies conducted in Africa. The meta‐regression analysis suggested that the pooled rate of S aureus contamination was lower for studies conducted in developed countries (odds ratio, 0.664; 95% CI, 0.509‐0.867; P = .004). No bias was found in the publication of the rates of S aureus and MRSA contamination. Conclusions: S aureus and MRSA contamination statuses of high‐touch items are worrisome and should be paid greater attention. Developing country status was a risk factor for S aureus contamination.

A prospective cohort study of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus carriage in neonates: the role of maternal carriage and phenotypic and molecular characteristics

Background Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), in mothers can cause serious outcomes in neonates. We aimed to elucidate the associations of S. aureus and MRSA carriage between mothers and neonates. Methods A prospective cohort study was conducted between August and November 2015 in two hospitals in Shenzhen, China. Chinese pregnant women and their neonates who met the inclusion criteria were included in this study; samples and relevant information were collected. We assessed maternal–neonatal associations by using Poisson regression models. Results Overall, 1834 mothers and their neonates were included in this study. The prevalence of isolate carriage among the mothers was as follows: S. aureus (nasal, 25.8%; vaginal, 7.3%; and nasal and vaginal, 3.3%) and MRSA (nasal, 5.7%; vaginal, 1.7%; and nasal and vaginal, 0.5%). The incidences of S. aureus and MRSA carriage among neonates were 3.3% and 0.8%, respectively. Of the 21 maternal–neonatal pairs with S. aureus carriage, 14 were concordant pairs with the same phenotypic and molecular characteristics. After adjustment, the relative risks and 95% confidence intervals (CIs) between the S. aureus carriage of neonates and nasal S. aureus carriage, vaginal S. aureus carriage, and both nasal and vaginal S. aureus carriage of mothers were 2.8 (95% CI, 1.6–4.8), 7.1 (95% CI, 4.1–12.4), and 9.6 (95% CI, 4.2–22.4), respectively. Conclusion S. aureus carriage in mothers increases the risk for neonates.

A large meta-analysis of the global prevalence rates of S. aureus and MRSA contamination of milk

ABSTRACT Past reports have indicated a high prevalence of milk contaminated with Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA), but the pooled prevalence rates of S. aureus and MRSA in pasteurized and boiled cows milk, raw cows milk, and raw Caprinae milk (raw sheeps milk and raw goats milk) and across different periods, continents, economic conditions and purchase locations remain inconsistent. We searched relevant articles published in PubMed, EMBASE, and Web of Science before July 2016. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement was used to evaluate the quality of 93 included studies. We observed that the pooled prevalence rates of S. aureus contamination in pasteurized and boiled cows milk, raw cows milk, and raw Caprinae milk were 15.4% (95% CI, 6.1–27.5%), 33.5% (95% CI, 29.5–37.7%) and 25.8% (95% CI, 17.5–35.0%), respectively. The pooled prevalence rates of MRSA contamination were 4.9% (95% CI, 0.0–15.7%), 2.3% (95% CI, 1.3–3.6%), and 1.1% (95% CI, 0.5–1.8%), respectively. The prevalence of S. aureus contamination in raw cows milk increased over time. However, the pooled prevalence of raw cows milk contaminated with S. aureus was lowest in European studies. These findings give an indication of the consequence of better milk regulation in Europe. High S. aureus prevalence rates in raw milk collected from farms and processing companies pose a potential threat to consumers. The implementation of good hygiene practices, appropriate health knowledge, and food safety principles at the farm level, as well as the prudent use of antibiotics in veterinary medicine and heat treatment before drinking, are necessary to reduce the potential risk of S. aureus and MRSA contamination.

Nasal colonization of Staphylococcus aureus colonal complex 5: Prevalence, influencing factors, and phenotypic and molecular characteristics in pregnant Chinese women

HighlightsThe prevalence of Staphylococcus aureus and methicillin‐resistant S aureus (MRSA) nasal colonization in pregnant Chinese women was moderate.Molecular characteristics of S aureus and MRSA isolates indicated possible cross‐transmission among multiple sources.Higher frequency of daily handwashing and weekly bathing can significantly decrease the prevalence of S aureus colonal complex 5 (CC5) and MRSA CC5 nasal colonization in the pregnant women. Background: Colonal complex 5 (CC5) has been referred to as the most pandemic community‐associated Staphylococcus aureus in most Asian countries. However, few studies have focused on CC5 isolates in pregnant women. The aim of this study was to determine the prevalence and phenotypic and molecular characteristics of S aureus and methicillin‐resistant S aureus (MRSA) CC5 nasal colonization in pregnant Chinese women. Methods: We performed a cross‐sectional study between August and November 2015 in 2 hospitals in Shenzhen, China. Pregnant women were asked to complete questionnaires, and nasal swabs were collected. Log‐binomial regression models were used to explore factors influencing S aureus and MRSA nasal colonization between the CC5 and non‐CC5 or non–S aureus groups. Polymerase chain reaction assays were used to detect the molecular characteristics of isolates. Results: Overall, 2,172 pregnant women were included in this study. The prevalence of S aureus and MRSA was 25.60% (n = 556) and 5.62% (n = 122), respectively. The multilocus sequence typing of S aureus isolates was diversified. A lower frequency of daily handwashing (<7) and weekly bathing (<7) were risk factors for the prevalence of S aureus (adjusted prevalence ratio [aPR], 1.13; 95% confidence interval [CI], 1.03‐1.41 and aPR, 1.22; 95% CI, 1.03‐1.45) and MRSA (aPR, 1.96; 95% CI, 1.23‐3.14 and aPR, 1.47; 95% CI, 1.21‐2.44) nasal colonization in the CC5 groups of pregnant women. Conclusions: The prevalence of S aureus and MRSA nasal colonization was moderate. The molecular characteristics of S aureus and MRSA isolates indicated possible cross‐transmission among multiple resources. A higher frequency of daily handwashing and weekly bathing significantly decreased the prevalence of S aureus and MRSA CC5 nasal colonization in the pregnant women.

Prevalence and characteristics of Staphylococcus aureus and methicillin-resistant Staphylococcus aureus nasal colonization among a community-based diabetes population in Foshan, China

Evidence suggests that diabetes might cause an increase in colonization of Staphylococcus aureus (S. aureus) and methicillin‐resistant S. aureus (MRSA) in community settings. We carried out a cross‐sectional study to determine the prevalence and influencing factors of S. aureus and MRSA nasal colonization among a community‐based diabetes population, and to identify the characteristics of the isolated strains.

Methicillin-Resistant Staphylococcus aureus Nasal Colonization in Chinese Children: A Prevalence Meta-Analysis and Review of Influencing Factors

Objective To determine the pooled prevalence and review the influencing factors of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization in Chinese children. Methods Articles published between January 2005 and October 2015 that studied prevalence or influencing factors of MRSA nasal colonization in Chinese children were retrieved from Chinese Biomedical Literature database (CBM), China National Knowledge Infrastructure (CNKI) database, Chinese VIP database, Chinese Wanfang database, Medline database and Ovid database. Prevalence and influencing factors were analyzed by STATA 13.1. Results Thirteen articles were included. The overall prevalence of MRSA nasal colonization was 4.4% (95% confidence interval [CI]: 0.027–0.062). With an MRSA prevalence of 3.9% (95% CI: 0.018–0.061) in healthy children and 5.8% (95% CI: 0.025–0.092) in children with underlying medical conditions. Children recruited in the hospitals presented MRSA prevalence of 6.4% (95% CI: 0.037–0.091), which was higher than those recruited in the communities [2.7% (95% CI: 0.012–0.043)]. A number of influencing factors for MRSA nasal colonization were noted in three eligible studies: gender (male vs female; OR: 0.67; 95% CI: 0.55–0.82), younger age (OR: 2.98; 95% CI: 1.31–6.96 and OR: 1.56; 95% CI: 1.21–2.00), attending day care centers (OR: 2.97; 95% CI: 1.28–6.76), having infectious diseases (OR: 2.31; 95% CI: 1.10–4.52), using antibiotics (OR: 2.77; 95% CI: 1.45–5.05), residing in northern Taiwan (OR: 1.41; 95% CI: 1.15–1.71), passive smoking (OR: 1.30; 95% CI: 1.02–1.63), and pneumococcal vaccination (OR: 1.22; 95% CI: 1.01–1.48). Conclusions Children could act as reservoirs of MRSA transmissions. Hospitals remained the most frequent microorganism-circulated settings. More MRSA infection control strategies are required to prevent the dissemination among children.