4.4. Proportion of K. peumoniae strains carrying genes encoding quinolone resistance (qnr)
Resistance to quinolone antibiotics is determined by the qnr gene located on different Integrons. This discovery is of great importance because it shows that quinolone resistance genes can spread horizontally between bacteria. It has been studied and discovered in many countries across all continents.
The rate of quinolone resistance genes in our study is equivalent to some studies of some countries: the authors Hyunjoo Pai and colleagues isolated qnrB rate was 40.5%, qnrA 3.8%; Myeong Hee Kim and colleagues in Korea studied Klebsiella pneumoniae strains isolated from hospitals and found that the total number of strains carrying qnr genes was 40.5%. Of which qnr B accounted for 85.7%, qnrS 14.3% and China from 2.4 to 15.1% [28], [81], [104]. With the rate of 38.3% carrying qnr resistance genes among strains carrying C3G resistance genes, it is also high compared to studies of other countries. This is an antibiotic that is also widely used and effective in treating infectious causes, so limiting the spread is an urgent issue that needs attention.
4.5. Identification of K. peumoniae strains carrying genes encoding resistance to third-generation cephalosporin (C3G) and quinolone (qnr) antibiotics
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This study has shown that a bacterial strain can simultaneously carry many genes encoding drug resistance on plasmids, the proportion of these strains accounts for up to 85%, which means that many genes encoding drug resistance are transmitted from one bacteria to another quickly in a short time and are very difficult to control, due to the horizontal transmission mechanism, through direct contact between bacteria containing plasmids carrying genes encoding drug resistance with another sensitive bacterium. In particular, these strains, in addition to carrying genes encoding resistance to β-lactam antibiotics, also have a significant proportion carrying genes encoding resistance to Quinonol at the same time, accounting for 22.4%. Quinolones and Cephalosponrins of the 3rd and 4th generations are antibiotics that are widely used and effective in treating infections. Therefore, to prevent the increase of multi-resistant strains, minimizing the spread of
Transmission of strains carrying the gene encoding C3G resistance also significantly reduced the spread of genes encoding quinolone resistance.
4.6. Identification of K. peumoniae strains carrying genes encoding resistance to third-generation cephalosporin (C3G) and quinolone (qnr) antibiotics located on plasmids
In our study, the PCR technique and the Southern Blot technique used are two molecular biology techniques with high sensitivity and specificity. With the use of specific primers that only multiply DNA fragments located on plasmids in the PCR technique and the use of the S1 restriction enzyme, which only specifically cuts on plasmid DNA fragments, the research results have twice confirmed the presence of the genes found on plasmid DNA. The second confirmation with the Southern Blot technique has reduced the error in the study to less than 100 times (according to the principle of statistical probability).
On the other hand, the results of this study showed that the rate of K. pneumoniae strains carrying genes encoding resistance to C3G and quinolone antibiotics located on plasmids was quite high, and at the same time, a strain carried many different types of genes. This is very significant, it shows that the spread of resistance genes will be much higher than the presence of genes encoding resistance located on chromosomal DNA, because it can be transmitted horizontally through direct contact between bacterial strains, and can transmit many resistance genes at the same time. This is a serious resistance mechanism, causing a very rapid increase in resistance in the pathogenic bacterial population.
With this study, we hope to contribute to further understanding of the antibiotic resistance mechanism of K. pneumoniae strains causing respiratory tract infections isolated at the National Children's Hospital, which will be the basis for doctors and clinical pharmacists to develop more effective treatment regimens.
CONCLUDE
1. Of 3,567 respiratory tract specimens of children aged 0 to 6 years old in the departments of Emergency, Neonatal, Pediatrics and Respiratory, 1,181 samples were positive. The positive culture rate was 33.1%. Of which, 7.4% of samples had 2 species. Gram-negative bacilli accounted for the majority of the bacterial strains isolated in general. Among the isolated bacterial species, K.pneumoniae accounted for the highest proportion at 22.61%, followed by Acinetobacter spp at 19.9% and p.aeruginosa at 18.37%.
2. From 3,567 respiratory specimens of children aged 0 to 6 were divided into two groups: NKHHCT (1,909) and combined NKHHCT (1,658).
- The positive culture rate of NKHHCT was 37.4%; Gram-negative bacilli accounted for the majority, of which K.pneumoniae was the leading 24.1%, followed by P.aeruginosa at 17.4%. The rate of isolating K. pneumoniae in the Neonatal Department was the highest at 13.0%, followed by the Respiratory Department at 8.7% and the lowest was the Emergency Resuscitation Department at 4.2%.
- The combined positive culture rate of NKHHCT was 28.1%; Gram-negative bacilli accounted for the majority, of which Acinetobacter. spp was the leading 29.8%, followed by K.pneumoniae 20.3%. The highest rate of isolated K.pneumoniae was in the Neonatal Department, followed by the ICU and HSN departments.
- Gram-positive cocci isolated in the NKHHCT group were higher than in the combined NKHHCT group.
3. Klebsiella strains are highly resistant to 2nd and 3rd generation cephacosporin antibiotics.
4 from 86.8% to 95%. K. pneumoniae strains are resistant to most antibiotics: cefuroxime: 93.8%, cephalothin 95.1% and ampicillin 99.2% - 100%, aminoglycoside antibiotics are highly resistant with a rate of 65.8% to 79.4%. They are still sensitive to imipenem and ciprofloxacin. The rate of multi-resistance is high, with many resistance patterns, mainly resistance to 9 to 12 antibiotics (75%). Strains resistant to all tested antibiotics appear. The rate of K. pneumoniae resistant to ≥9 antibiotics in deceased children is higher than that of K. pneumoniae strains resistant to <9 antibiotics, the rate
The rate of K. pneumoniae resistant to ≥9 antibiotics in pediatric patients who died in the combined NKHHCT group was significantly higher than in the NKHHCT group.
- The ESBL production rate in isolated K.pneumoniae strains was 56.9%, highest in the Surgical Intensive Care Department at 71.8% and there was a difference between departments.
- MIC has a breakpoint at high concentrations, greater than the antibiotic resistance standard MIC. Our results of determining the minimum inhibitory concentrations MIC 50 and MIC 90 confirmed that the level of resistance to β-lactam antibiotics of the K. pneumoniae strains in the study was very high.
4. The rate of C 3 G and qinolon resistance genes in the study showed:
- High rate of C 3 G resistance gene carriers: CTXM-3; 30.8%; CTXM-9: 73.8%; SHV: 88.8%; TEM: 80.4%. Total CTXM family: 92.5%, rate of strains carrying both CTX-M-3 and CTX-M-9 genes in the study was 10.3%. Rate of simultaneously carrying all C 3 G resistance genes was 85%.
- The rate of carrying the qnr resistance gene is 38.3%. Of which qnrA: 2.4%; qnrB: 17% and
mainly qnrS: 80.6%.
- The rate of simultaneous carriage of C3G and qnr resistance genes in the study was 22.4%.
PROPOSAL
1. Effective treatment and prevention of the development and spread of drug-resistant K. pneumoniae strains . Testing and treatment according to antibiotic susceptibility testing should be emphasized.
2. There should be more research on antibiotic resistance genes of pathogenic bacteria and their epidemiology to have measures to prevent and control these bacteria.