Characteristics and genomic epidemiology of colistin-resistant Enterobacterales from farmers, swine, and hospitalized patients in Thailand, 2014-2017.

BACKGROUND: Colistin is one of the last resort therapeutic options for treating carbapenemase-producing Enterobacterales, which are resistant to a broad range of beta-lactam antibiotics. However, the increased use of colistin in clinical and livestock farming settings in Thailand and China, has led to the inevitable emergence of colistin resistance. To better understand the rise of colistin-resistant strains in each of these settings, we characterized colistin-resistant Enterobacterales isolated from farmers, swine, and hospitalized patients in Thailand. METHODS: Enterobacterales were isolated from 149 stool samples or rectal swabs collected from farmers, pigs, and hospitalized patients in Thailand between November 2014-December 2017. Confirmed colistin-resistant isolates were sequenced. Genomic analyses included species identification, multilocus sequence typing, and detection of antimicrobial resistance determinants and plasmids. RESULTS: The overall colistin-resistant Enterobacterales colonization rate was 26.2% (n = 39/149). The plasmid-mediated colistin-resistance gene (mcr) was detected in all 25 Escherichia coli isolates and 9 of 14 (64.3%) Klebsiella spp. isolates. Five novel mcr allelic variants were also identified: mcr-2.3, mcr-3.21, mcr-3.22, mcr-3.23, and mcr-3.24, that were only detected in E. coli and Klebsiella spp. isolates from farmed pigs. CONCLUSION: Our data confirmed the presence of colistin-resistance genes in combination with extended spectrum beta-lactamase genes in bacterial isolates from farmers, swine, and patients in Thailand. Differences between the colistin-resistance mechanisms of Escherichia coli and Klebsiella pneumoniae in hospitalized patients were observed, as expected. Additionally, we identified mobile colistin-resistance mcr-1.1 genes from swine and patient isolates belonging to plasmids of the same incompatibility group. This supported the possibility that horizontal transmission of bacterial strains or plasmid-mediated colistin-resistance genes occurs between humans and swine.

Fecal Carriage Rate of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae as a Proxy Composite Indicator of Antimicrobial Resistance in a Community in Thailand.

BACKGROUND: Increasing awareness of and understanding about antimicrobial resistance (AMR), promoting changes in behavior, and monitoring of AMR in the community are challenging, as AMR is associated with many contributing factors that are difficult to assess individually. This study aimed to determine the effectiveness of a community-based AMR campaign for improving awareness, understanding, and behavior relating to antibiotic use and AMR in Thailand and to assess if fecal carriage of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae could be a proxy composite indicator of AMR in the community. METHODS: This study was conducted in 4 communities that are home to approximately 400 000 people. A self-administered questionnaire on awareness, understanding, and behavior relating to antibiotic use and AMR was responded to by 20 521 and 19 634 adults before and immediately after the AMR campaign, respectively, at the household level. Fecal samples were collected from 534 adults before the AMR campaign and from 709 adults at 18 months after the AMR campaign to determine presence of ESBL-producing Enterobacteriaceae. RESULTS: Awareness, understanding, and behavior relating to antibiotic use and AMR, as assessed by a self-administered questionnaire, were significantly improved after the AMR campaign. The fecal carriage rate of ESBL-producing Enterobacteriaceae decreased from 66.5% before to 44.6% after the AMR campaign (P < .01). CONCLUSIONS: Our AMR campaign was effective for improving awareness, understanding, and behavior relating to antibiotic use and AMR among people in the community at the household level, and the prevalence of fecal carriage of ESBL-producing Enterobacteriaceae seemed to be decreased after the AMR campaign. Fecal carriage rate of ESBL-producing Enterobacteriaceae may be a proxy composite indicator of AMR in the community.

Multilocus sequence typing and bla ESBL characterization of extended-spectrum beta-lactamase-producing Escherichia coli isolated from healthy humans and swine in Northern Thailand.

PURPOSE: Here, we investigated the genetic relationships and characteristics of extended- spectrum beta-lactamase-producing Escherichia coli (ESBL-E. coli) isolates from healthy hosts, humans in the community and swine among the livestock of Amphor Mueang, Lamphun Province, Thailand. PATIENTS AND METHODS: Four hundred and nine rectal swabs were collected from healthy people and swine. A total of 212 ESBL-E. coli was isolated and phenotypically confirmed by a combination disk method. Putative ESBL-encoding genes, including bla CTX-M, bla TEM, and bla SHV, were examined by multiplex-PCR. Randomly selected 42 ESBL-E. coli isolates were whole genome sequenced to characterize the ESBL-encoding genes and identify additional antimicrobial resistance genes. The genetic relatedness of 212 ESBL-E. coli was investigated by multilocus sequence typing. RESULTS: Overall, bla CTX-M was the dominant ESBL-encoding gene found in 95.75% of the isolates, followed by bla TEM (60.85%) and bla SHV (2.40%). While bla CTX-M-55 was the most common bla ESBL subgroup found in this study. Whole genome sequencing showed a total of 15 different antimicrobial resistance genes other than bla ESBL, including sul, qnr, aph(3')-Ia, among the selected 42 ESBL-E. coli isolates. Over half of the ESBL-E. coli (56.60%) carried bla CTX-M co-existing with bla TEM. The most common sequence types (STs) identified from human isolates were ST131, ST101, and ST70 while those isolated from swine were ST10, ST48, and ST131. ST131 strains carrying bla CTX-M were the major isolated ESBL-E. coli strains, supporting a previous study that considered this strain truly pathogenic. Noticeably, 66.51% of ESBL-E. coli strains shared 19 identical STs, including a host-restricted ST131 between humans and swine, suggesting that transmission between these two hosts might be possible. CONCLUSION: Proof of a direct transfer of ESBL-E. coli from animals to humans, or vice versa, is required for further elucidation. The ESBL-E. coli isolated from both types of healthy hosts may serve as a reservoir for community-acquired antimicrobial resistance.

Epidemiology of Antibiotic Use and Antimicrobial Resistance in Selected Communities in Thailand.

OBJECTIVE: To generate epidemiological information regarding antibiotic use and antimicrobial resistance (AMR) in targeted communities for use by the Thailand AMR Containment and Prevention Program. MATERIAL AND METHOD: A survey of antibiotics sold by 215 grocery stores and retail shops located in the target communities was done by the local people who were instructed to purchase specified antibiotics and to present to such stores and shops with symptoms of sore throat, backache, common cold, acute diarrhea, inflamed uterus, and dysuria. The purchased drugs were then identified and recorded. Contamination of extended-spectrum ß-lactamase (ESBL)-producing E. coli was identified in 174 samples of foods and open water sources collected from the target communities. Carriage of ESBL-producing E. coli in gastrointestinal tracts of 534 adults living in the target communities was performed by stool sample culture. One thousand three hundred one patients with upper respiratory infection (URI) and 235 patients with acute diarrhea who attended the tambon health promoting hospitals located in the target communities were monitored for their clinical outcomes of treatments. The patients with URI and acute diarrhea with no indication of antibiotic received symptomatic treatments as appropriate and they were followed via telephone contact every few days until all symptoms related to URI and acute diarrhea disappeared. The data were analyzed by descriptive statistics. RESULTS: Antibiotics were sold to the local people who were presenting with common ailments at many grocery stores and retail shops in their respective communities. In almost all cases, antibiotics were inappropriately given. Overall prevalence of ESBL-producing E. coli contamination in foods and open water sources was 26.4%. ESBL-producing E. coli was isolated from fresh meat and open water sources in many samples. Overall prevalence of ESBL-producing E. coli carriage in gastrointestinal tracts of the adults cultured was 66.5%. All patients with URI and acute diarrhea who had no indication of antibiotics and did not receive antibiotics had either cure or favorable response within seven days of start of symptomatic treatment. CONCLUSION: Antibiotics are widely available and are inappropriately sold and given by grocery stores and retail shops located within local communities in Thailand. Antibiotic-resistant bacteria commonly and freely circulate within the community. Patients with URI and acute diarrhea with no indication for antibiotic therapy can be treated without antibiotics. Findings and observations from this study will be used as part of a social marketing campaign on prevention and containment of AMR to educate people living within communities in Thailand.

Effectiveness of disinfectant wipes for decontamination of bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital.

OBJECTIVE: To determine the effectiveness of Virusolve+ disinfectant wipes and PAL disinfectant wipes for decontamination of inoculated bacteria on patients' environmental and medical equipment surfaces at Siriraj Hospital. MATERIAL AND METHOD: Tryptic soy broths containing MRSA and XDR A. baumannii were painted onto the surfaces of patient's stainless steel bed rail, patient's fiber footboard, control panel of infusion pump machine and control panel of respirator. The contaminated surfaces were cleaned by either tap water, tap water containing detergent, Virusolve+ disinfectant wipes or PAL disinfectant wipes. The surfaces without any cleaning procedures served as the control surface. The contaminated surfaces cleaned with the aforementioned procedures and control surfaces were swabbed with cotton swabs. The swabs were streaked on agar plates to determine the presence of MRSA and XDR A. baumannii. RESULTS: MRSA and XDR A. baumannii were recovered from all control surfaces. All surfaces cleaned with tap water or tap water containing detergent revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with tap water containing detergent were less than those cleaned with tap water alone. All surfaces cleaned with PAL disinfectant wipes also revealed presence of both MRSA and XDR A. baumannii. However the amounts of bacteria on the surfaces cleaned with PAL disinfectant wipes were less than those cleaned with tap water containing detergent. No bacteria were recovered from all surfaces cleaned with Virusolve+ disinfectant wipes. CONCLUSION: Virusolve+ disinfectant wipes were more effective than tap water; tap water containing detergent and PAL disinfectant wipes for decontamination of bacteria inoculated on patients environmental and medical equipment surfaces at Siriraj Hospital.