Antibiotic Resistance, Biofilm Formation, and Persistent Phenotype of Klebsiella pneumoniae in a Vietnamese Tertiary Hospital: A Focus on Amikacin.

Klebsiella pneumoniae stands out as a major opportunistic pathogen responsible for both hospital- and community-acquired bacterial infections. This study comprehensively assesses the antibiotic resistance, amikacin persistent patterns, and biofilm-forming ability of 247 isolates of K. pneumoniae obtained from an intensive care unit of a tertiary hospital in Vietnam. Microdilution assays, conducted on a 96-well plate, determined the minimum inhibitory concentrations (MICs) of amikacin. Susceptibility data for other antibiotics were gathered from the antibiogram profile. Stationary-phase bacteria were exposed to 50 × MIC, and viable bacteria counts were measured to determine amikacin persistence. Biofilm forming capacity on 96-well polystyrene surfaces was assessed by biomass and viable bacteria. The prevalence of resistance was notably high across most antibiotics, with 64.8% classified as carbapenem-resistant K. pneumoniae and 81.4% as multidrug resistant. Amikacin, however, exhibited a relatively low rate of resistance. Of the isolates, 58.2% demonstrated a moderate to strong biofilm formation capacity, and these were found to be poorly responsive to amikacin. K. pneumoniae reveals a significant inclination for amikacin persistence, with ∼45% of isolates displaying an antibiotic antibiotic-survival ratio exceeding 10%. The study sheds light on challenges in treating of K. pneumoniae infection in Vietnam, encompassing a high prevalence of antibiotic resistance, a substantial ability to form biofilm, and a notable rate of antibiotic persistence.

Allopurinol-induced severe cutaneous adverse reactions in Vietnamese: the role of HLA alleles and other risk factors.

Aim: To reveal the association of three class I HLA alleles, including HLA-A*33:03, HLA-B*58:01 and HLA-C*03:02, and allopurinol-induced severe cutaneous adverse reactions (SCARs) in Vietnamese patients. Methods: A case-control study on 100 allopurinol-induced SCARs patients, 183 tolerant controls and 810 population controls was performed. The HLA-A*33:03 and HLA-C*03:02 alleles were detected with the nested allele-specific PCR method; the HLA-B*58:01 allele was detected with the sequence-specific primer PCR method. Results: There were strong associations between HLA-B*58:01 and HLA-C*03:02 and allopurinol-induced SCARs. Specific associations were found between HLA-B*58:01 and Stevens-Johnson syndrome/toxic epidermal necrolysis and between HLA-C*03:02 and drug reaction with eosinophilia and systemic symptoms, with a gene dosage effect. The multivariate regression analysis indicated two significant independent risk factors: HLA-B*58:01/HLA-C*03:02 and estimated glomerular filtration rate <60 ml/min/1.73 m2. The specificity, positive predictive value and negative predictive value of HLA-B*58:01 testing were higher than the HLA-C*03:02 or the multiplex testing, especially in patients with impaired renal function. Conclusion: The results supported pre-treatment HLA-B*58:01 testing in Vietnamese patients with declined renal function to prevent SCARs.

The association between HLA-B*15:02 and phenytoin-induced severe cutaneous adverse reactions: a meta-analysis.

Aim: Phenytoin (PHT) is a common anticonvulsant agent known for inducing severe cutaneous adverse reactions (SCARs). HLA-B*15:02 as a risk factor of PHT-induced SCARs was reported in numerous studies with inconsistent results. This meta-analysis aimed to establish pooling evidence of this association. Materials & methods: Pooled odds ratios (ORs) with 95% CIs were estimated using a random-effects model. Results: A total of 11 studies on 1389 patients, were included for the analyses. There was a significant association between HLA-B*15:02 and PHT-induced SCAR (pooled OR = 2.29, 95% CI: 1.25-4.19, p = 0.008). Furthermore, there was a significant association regarding Stevens-Johnson syndrome/toxic epidermal necrolysis (OR = 3.63, 95% CI: 2.15-6.13, p < 0.001) but no association regarding drug reaction with eosinophilia and systemic symptom. Conclusion: The results supported the recommendations of HLA-B*15:02 screening before treatment with PHT.

A novel nested allele-specific PCR protocol for the detection of the HLA-A*33:03, a SCAR-associated allele, in Vietnamese people.

BACKGROUND: Severe cutaneous adverse drug reactions (SCARs) are rare but deadly drug reactions with severe damages to patients. One of the most well-known SCARs risk factors is the human leukocyte antigen (HLA) genes polymorphism. Among the HLA polymorphic alleles, the HLA-A*33:03 allele has been found in association with SCARs induced by various drugs, especially in Asian people. There has not been any report on the specific detection protocol of the HLA-A*33:03 allele. OBJECTIVE: This study aimed to design a nested AS-PCR protocol for detecting and distinguishing diplotype genotype of the HLA-A*33:03 allele. METHODS: A nested allele-specific (AS)-PCR protocol with four primer sets was designed. The method was compared with the Sanger sequencing method on 100 samples of unknown genotypes of unrelated Vietnamese people. RESULTS: The nested AS-PCR method could identify the HLA-A*33:03 allele and the HLA-A*33:03 diplotype genotypes. Comparison with the Sanger sequencing method showed an absolute agreement (κ = 1.00, p < 0.001). The nested ASPCR protocol had a sensitivity of 100% (95%CI: 92.13-100%) and a specificity of 100% (95%CI: 93.51-100%). The protocol was used for the determination of HLA-A*33:03 allele distribution in 810 unrelated Vietnamese Kinh people, showing a frequency of HLA-A*33:03 carriers of 19.6% and an allele frequency of 10.55%. CONCLUSIONS: A novel nested AS-PCR method with a hundred-percent sensitivity and a specificity for the HLA-A*33:03 allele detection was reported. The protocol can be applied for the stratification of patients at SCAR risks with various drugs.

A Novel Allele-Specific PCR Protocol for the Detection of the HLA-C*03:02 Allele, a Pharmacogenetic Marker, in Vietnamese Kinh People.

BACKGROUND: Allopurinol, a common anti-hyperuricemia drug, is well known as an inducer of severe cutaneous adverse drug reactions (SCARs). One of the most well-defined risk factors of allopurinol-induced SCARs is the presence of polymorphic alleles of human leukocyte antigen (HLA) genes, such as HLA-B*58:01 and HLA-C*03:02 alleles. There is no commercial test or published in-house protocol for the specific detection of the HLA-C*03:02 allele. In this article, we established for the first time a simple allele-specific (AS) PCR method to identify HLA-C*03:02 allele carriers, and at the same time, determine their zygosities. METHODS: A two-step AS-PCR protocol, using four primer sets, was designed to specifically amplify and differentiate the HLA-C*03:02 allele from 17 other HLA-C alleles found in Vietnamese people. The protocol was validated with PCR-sequencing-based typing (SBT) of 100 samples of unknown genotypes. RESULTS: The PCR protocol can detect the HLA-C*03:02 allele and determine the zygosity. The results of this protocol were highly consistent with those of the SBT (ĸ = 0.98, p < 0.001). Regarding the specific detection of the HLA-C*03:02 allele, the PCR protocol had a sensitivity of 100% (95% CI: 91.61-100%) and specificity of 98.3% (95% CI: 90.9-99.7%). The protocol was used to determine the distribution of the HLA-C*03:02 allele in 810 unrelated Vietnamese Kinh people, 14.2% of which were HLA-C*03:02 carriers, the allele frequency was 7.5%. CONCLUSION: A novel AS-PCR protocol with a sensitivity of 100% for the detection of the HLA-C*03:02 allele was established. The protocol can be used for personalized treatment with allopurinol in order to minimize the risk of SCARs in Vietnamese people as well as in other Asian populations with similar genetic characteristics.