Antibacterial effect of acetic acid during an outbreak of carbapenem-resistant Acinetobacter baumannii in an ICU (II).

INTRODUCTION: Acetic acid (AA) has been commonly used in medicine as an antiseptic agent for the past 6000 years. This study evaluated the antibacterial effect of AA during an outbreak in an intensive care unit (ICU) facility in Baja California Sur, México. METHODOLOGY: Thirty-five environmental samples were collected, subsequently, disinfection with AA (4%) was performed, and two days later the same areas were sampled inside the ICU facility. Carbapenem-resistant A. baumannii (CRAB) was detected with loop-mediated isothermal amplification assay (Garciglia-Mercado et al. companion paper), targeting blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP and blaVIM genes. CRAB isolates before and after disinfection were compared by PFGE. RESULTS: Eighteen (54.5%) and five (14.3%) of thirty-five environmental samples were identified as Acinetobacter baumannii before and after disinfection, respectively, showing a significant decrease of 85.7% (p < 0.05) both by Loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR). Furthermore, the presence of blaOXA-23-like and blaOXA-58-like genes significantly decreased (p < 0.05) both by LAMP and PCR methods. PFGE genotype showed high similarity among CRAB isolates before and after disinfection, suggesting wide clonal dissemination in the ICU facility. CONCLUSIONS: This study demonstrated the novel application of AA with the LAMP assays developed for detecting CRAB. AA promises to be a cheap and efficacious disinfectant alternative to both developed and especially developing countries, preventing the spread of this organism in the environment and to other susceptible patients in health care settings.

Development of a LAMP method for detection of carbapenem-resistant Acinetobacter baumannii during a hospital outbreak.

INTRODUCTION: Carbapenem-resistant A. baumannii (CRAB) represents a public health threat increasing worldwide. We assess the suitability of a loop-mediated isothermal amplification (LAMP) method for on-site screening of CRAB in a hospital facility. METHODOLOGY: A set of six primers were designed for recognizing eight distinct sequences on six targets: blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP, and blaVIM. A LAMP method was developed, optimized and evaluated for the identification of CRAB in thirty-three environmental samples from an outbreak in an Intensive Care Unit (ICU) facility. RESULTS: The sensitivity of the LAMP assay for the detection of A. baumannii was ten-fold higher than the PCR assay (1.0 ng.µL-1). The LAMP assays showed a higher detection rate for CRAB samples and robust diagnosis performance in comparison to a conventional PCR, with clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100% for blaOXA-23-like, blaOXA-51-like and blaVIM. CONCLUSIONS: The developed LAMP assays are powerful tools that can be useful in on-site screening of CRAB causing local outbreaks in clinics and hospitals facilities where costs and equipment restraints are imperative.

Integrated food chain surveillance system for Salmonella spp. in Mexico.

Few developing countries have foodborne pathogen surveillance systems, and none of these integrates data from humans, food, and animals. We describe the implementation of a 4-state, integrated food chain surveillance system (IFCS) for Salmonella spp. in Mexico. Significant findings were 1) high rates of meat contamination (21.3%-36.4%), 2) high rates of ceftriaxone-resistant S. Typhimurium in chicken, ill humans, and swine (77.3%, 66.3%, and 40.4% of S. Typhimurium T isolates, respectively), and 3) the emergence of ciprofloxacin resistance in S. Heidelberg (10.4%) and S. Typhimurium (1.7%) from swine. A strong association between Salmonella spp. contamination in beef and asymptomatic Salmonella spp. infection was only observed in the state with the lowest poverty level (Pearson r = 0.91, p<0.001). Pulsed-field gel electrophoresis analysis of 311 S. Typhimurium isolates showed 14 clusters with 102 human, retail meat, and food-animal isolates with indistinguishable patterns. An IFCS is technically and economically feasible in developing countries and can effectively identify major public health priorities.