Genomic analysis revealing the resistance mechanisms of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae isolated from pig and humans in Malaysia.

Extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae has been associated with a wide range of infections in humans and animals. The objective of this study was to determine the genomic characteristics of two multiple drug resistant, ESBLs-producing K. pneumoniae strains isolated from a swine in 2013 (KP2013Z28) and a hospitalized patient in 2014 (KP2014C46) in Malaysia. Genomic analyses of the two K. pneumoniae strains indicated the presence of various antimicrobial resistance genes associated with resistance to ß-lactams, aminoglycosides, colistin, fluoroquinolones, phenicols, tetracycline, sulfonamides, and trimethoprim, corresponding to the antimicrobial susceptibility profiles of the strains. KP2013Z28 (ST25) and KP2014C46 (ST929) harbored 5 and 2 genomic plasmids, respectively. The phylogenomics of these two Malaysian K. pneumoniae, with other 19 strains around the world was determined based on SNPs analysis. Overall, the strains were resolved into five clusters that comprised of strains with different resistance determinants. This study provided a better understanding of the resistance mechanisms and phylogenetic relatedness of the Malaysian strains with 19 strains isolated worldwide. This study also highlighted the needs to monitor the usage of antibiotics in hospital settings, animal husbandry, and agricultural practices due to the increase of ß-lactam, aminoglycosides, tetracycline, and colistin resistance among pathogenic bacteria for better infection control.

Molecular characterization of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae from a Malaysian hospital.

Multidrug-resistant (MDR) and extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae associated with nosocomial infections have caused serious problems in antibiotic management with limited therapeutic choices. This study aimed to determine the genotypic and phenotypic characteristics of K. pneumoniae strains isolated from a tertiary hospital in Malaysia. Ninety-seven clinical K. pneumoniae strains were analyzed for antimicrobial susceptibility, all of which were sensitive to amikacin and colistin (except one strain), while 31.9 % and 27.8 % were MDR and ESBL producers, respectively. PCR and DNA sequencing of the amplicons indicated that the majority of MDR strains (26/27) were positive for blaTEM, followed by blaSHV (24/27), blaCTX-M-1 group (23/27), blaCTX-M-9 group (2/27), and mcr-1 (1/27). Thirty-seven strains were hypervirulent and PCR detection of virulence genes showed 38.1 %, 22.7 %, and 16.5 % of the strains were positive for K1, wabG, and uge genes, respectively. Genotyping by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) showed that these strains were genetically diverse and heterogeneous. Sequence types, ST23, ST22, and ST412 were the predominant genotypes. This is the first report of colistin-resistant K. pneumoniae among clinical strains associated with mcr-1 plasmid in Malaysia. The findings in this study have contributed to the effort in combating the increase in antimicrobial resistance by providing better understanding of genotypic characteristics and resistance mechanisms of the organisms.

Molecular Characterization of Multidrug-Resistant and Extended-Spectrum Beta-Lactamase-Producing Klebsiella pneumoniae Isolated from Swine Farms in Malaysia.

Aims: The high prevalence of multidrug resistance (MDR) and extended-spectrum ß-lactamase (ESBL)-producing Klebsiella pneumoniae associated with nosocomial infections has caused serious therapeutic challenges. The objectives of this study were to determine the genotypic and phenotypic characteristics of K. pneumoniae strains isolated from Malaysian swine farms and the transferability of ESBL genes by plasmids. Results: A total of 50 K. pneumoniae strains were isolated from 389 samples, which were collected from healthy and unhealthy pigs (swine rectum and oral cavities), healthy farmers (human rectum, urine, and nasal cavities), farm's environment, and animal feeds from seven Malaysian swine farms. Antimicrobial susceptibility analysis of these 50 K. pneumoniae strains showed that the majority (86%) were resistant to tetracycline, while 44% and 36% of these strains were MDR and ESBL producers, respectively. PCR and DNA sequencing of the amplicons showed the occurrence of blaTEM (15/18), blaSHV (15/18), blaCTX-M-1 group (7/18), and blaCTX-M-2 group (2/18), while only class 1 integron-encoded integrase was detected. Conjugation experiments and plasmid analysis indicated that the majority of the ESBL genes were plasmid encoded and the plasmids in 11 strains were conjugative. Genotyping by pulsed-field gel electrophoresis and repetitive extragenic palindrome-polymerase chain reaction (REP-PCR) showed that these 50 strains were genetically diverse with 44 pulsotypes and 43 REP-PCR subtypes. Conclusions: ESBL-producing K. pneumoniae strains showed high resistance to tetracycline as this antibiotic is used for prophylaxis and therapeutic purposes at the swine farms. The findings in this study have drawn attention to the issue of increasing MDR in animal husbandry and it should be taken seriously to prevent the spread and treatment failure due to antimicrobial resistance.

The emergence of colistin-resistant Klebsiella pneumoniae strains from swine in Malaysia.

OBJECTIVE: Colistin is the last line of therapy for infections caused by multidrug-resistant Gram-negative bacteria. The objective of this study was to determine the phenotypic and genotypic characteristics of colistin-resistant Klebsiella pneumoniae (K. pneumoniae) isolated from swine samples in Malaysia. METHODS: A total of 46 swine K. pneumoniae strains isolated from 2013-2015 in Malaysia were analysed for the production of extended-spectrum ß-lactamases and carbapenemase. The resistance traits and genetic diversity of these strains were characterised by polymerase chain reaction, conjugation, plasmid analysis, and pulsed-field gel electrophoresis. RESULTS: Nineteen of 46 strains were multidrug resistant while 13 were resistant to colistin. The majority of colistin-resistant strains harboured blaTEM gene (92.3%), followed by blaSHV (69.23%), blaCTXM-1 (38.46%), and blaMCR-1 (23.08%). All three colistin-resistant strains had transferable plasmids and the colistin resistance gene blaMCR-1. Genotyping by pulsed-field gel electrophoresis showed high genetic diversity among the K. pneumoniae and that the colistin-resistant K. pneumoniae strains were heterogenous. CONCLUSION: It is believed that this is the first report of colistin-resistant K. pneumoniae among swine strains associated with mcr-1 plasmid in Malaysia. Due to the emergence of ß-lactam, carbapenem and colistin resistance, the use of colistin in animal husbandry and agriculture should be avoided to prevent treatment failure.