A gloves-associated outbreak of imipenem-resistant Acinetobacter baumannii in an intensive care unit in Guangdong, China.

BACKGROUND: Imipenem-resistant Acinetobacter baumannii (IRAB) is an important cause of hospital-acquired infection. We aimed to describe an outbreak of IRAB infection and to investigate its possible source in an intensive care unit. METHODS: An environmental investigation was undertaken. Antimicrobial susceptibility testing was performed by microdilution. These isolates were genotyped by use of repetitive extragenic palindromic polymerase chain reaction (rep-PCR; DiversiLab). The study included 11 patients infected with IRAB and 14 control patients free of IRAB. Case and control patients were compared for possible predisposing factors. A multifaceted intervention was implemented to control the outbreak. RESULTS: Thirty-nine IRABs were isolated from patients and the environmental surveillance culture in August, November, and December 2011. All isolates were resistant to imipenem. The IRAB strains belonged to seven clones (A-G) by the use of rep-PCR. There were four epidemic clones (D-G) in the outbreak, and Clone D was predominant. For the case-control study, patients with chronic obstructive pulmonary disease were susceptible to infection with IRAB. The hospital mortality of the case group was significantly higher than that of the control group. CONCLUSIONS: The outbreak strains were transmitted among infected patients and equipment by inappropriate use of gloves. A combination of aggressive infection control measures is essential for preventing recurrent nosocomial outbreaks of IRAB.

Characterized of class I integron in Acinetobacter baumannii isolated from upper respiratory tract.

OBJECTIVE: To characterize the class I integron in Acinetobacter baumannii and to analyze the correlation between integron and drug resistance. METHODS: In total 187 strains were collected between 2008 and 2009. All strains were tested by Kirb-Bauer disk diffusion test for drug resistance. PCR and DNA sequencing were used to detected class I integrase gene and to clarify the context of gene cassette. RESULTS: Class I integrase gene was detected in 100 (53.4%) of the isolates analyzed. Seven different gene cassettes were identified, including a new integron (GenBank: HQ322622) carrying an unknown protein probably associated with recombination. The vast majority of the cassettes encoded amonoglycoside resistance gene, including aacA4, aadA1, aacC1, aac6 II , aadA2. Susceptibility data show that strains carrying class I integron were significantly more resistant to all of the antibiotics tested than isolates lacking class I integron. The correlation between the presence of integron and the multidrug-resistance of A. baumannii was statistically significant. CONCLUSION: Drug resistance genes integrated by Class I integron were widespread in A. baumannii. Class I integron plays an important role in resistance of A. baumannii.

Novel rare alleles of ABCA1 are exclusively associated with extreme high-density lipoprotein-cholesterol levels among the Han Chinese.

BACKGROUND: High-density lipoprotein (HDL) is a major plasma lipoprotein directly associated with cholesterol metabolism. The ATP binding cassette transporter 1 gene (ABCA1) is one of the major genes modulating plasma levels of HDL-cholesterol (HDL-C). Rare alleles of ABCA1 associated with extreme HDL-C concentrations have not been previously investigated in the Chinese. METHODS: Blood samples were collected from 470 subjects whose HDL-C concentrations were within the top 5% of the distribution, 335 subjects in the lowest 5%, and 220 within the range 5%-95%. First, we sequenced all exons of the ABCA1 gene from 50 subjects from the group with extremely high HDL-C, and 50 from the group with extremely low HDL-C concentrations. Next, in the remaining subjects, we genotyped the non-synonymous variants identified exclusively with either extreme group. RESULTS: Four novel non-synonymous alleles were identified; all were rare. Alleles c.3029C>T (p.Ala1010Val) and c.5399A>G (p.Asn1800Ser) were found exclusively in the low group, c.2031C>A (p.Asp677Glu) and c.2660G>T (p.Cys887Phe) exclusively in the high group. CONCLUSIONS: Our results show that some rare alleles of ABCA1 are associated with marked phenotypes, supporting the "rare-variant common-disease" hypothesis. Certain alleles also provide tools for identifying individuals at high risk of dyslipidaemia, allowing for early therapeutic intervention.