High prevalence of methicillin-resistant coagulase-negative staphylococci isolated from a university environment in Thailand Authors Rathanin Seng Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand. Udomluk Leungtongkam Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand. Rapee Thummeepak Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand. Wassana Chatdumrong Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand; Centre of Excellence in Medical Biotechnology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand Sutthirat Sitthisak Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand; Centre of Excellence in Medical Biotechnology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand Keywords: Staphylococcus spp., methicillin-resistant coagulase negative staphylococci, drug resistance, gene qacA/B, Phitsanulok (Thailand) Abstract The present study was conducted to isolate and characterize the molecular epidemiology of the methicillin-resistant staphylococci in the general university environment, where all five locations; the library, restrooms, canteens, computer rooms and outdoor surfaces, are in common use by a large population of students. We used Mannitol Salt Agar (MSA) supplemented with 4 μg/ml of oxacillin to screen the methicillin-resistant staphylococci. The species level was identified by PCR of rdr (Staphylococcus epidermidis), groESL (Staphylococcus haemolyticus) and nuc (Staphylococcus aureus and Staphylococcus warneri) genes and DNA sequencing of tuf and dnaJ genes. The susceptibility patterns of the isolates were determined using the disk diffusion method. Antibiotic and disinfectant resistance genes, together with SCCmec types, were detected by the PCR method. The methicillin resistant-staphylococci were isolated from 41 of 200 samples (20.5%), and all of them were found to be methicillin-resistant coagulase negative staphylococci (MR-CoNS). The library had the highest percentage of contamination, with 43.3% of the samples found to be contaminated. All isolates belonged to 6 different species including S. haemolyticus, S. epidermidis, S. warneri, S. cohnii, S. saprophyticus and S. hominis. The antimicrobial resistance rates were highest against penicillin (100%), then cefoxitin (73.1%), erythromycin (73.1%) and oxacillin (68.3%). Altogether, the isolates were approximately 61.0% multidrug resistant (MDR), with the S. epidermidis isolates being the most multidrug resistant (P < 0.05). The prevalence of the qacA/B gene was detected in 63.4% of the isolates, and SCCmec could be typed in 43.9% (18/41) of the isolates. The type range was: II (n = 1), IVd (n = 1), I (n = 2), V (n = 6), IVa (n = 8) and untypeable (n = 23). This result indicates that these university environments are contaminated with methicillin-resistant coagulase negative staphylococci that carry various SCCmec types and high rate of disinfectant resistance genes. [Int Microbiol 20(2):65-73 (2017)]Keywords: Staphylococcus spp. · methicillin-resistant coagulase negative staphylococci · drug resistance · gene qacA/B · Phitsanulok (Thailand) Author Biography Wassana Chatdumrong, Department of Microbiology and Parasitology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand; Centre of Excellence in Medical Biotechnology, Faculty of Medical Sciences, Naresuan University, Phitsanulok, Thailand Downloads PDF Issue Vol. 20 No. 2 (2017) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. 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