Association between methotrexate-induced Stevens-Johnson syndrome/toxic epidermal necrolysis and furosemide: a real-world disproportionality analysis.

BACKGROUND: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare and life-threatening skin adverse reactions that are usually induced by drugs. This study aimed to assess the association between methotrexate and SJS/TEN when combined with furosemide. RESEARCH DESIGN AND METHODS: Data on suspicious, interactions (PS, SS, I) from the FDA Adverse Event Reporting System database for 2016-2021 were analyzed using the reporting odds ratio (ROR), information component (IC), proportional reporting ratio (PRR) and the Medications and Health Care Products Regulatory Agency (MHRA). RESULTS: We identified 28 case reports of TEN associated with the combination of furosemide and methotrexate and 10 reports of SJS associated with furosemide and methotrexate. The association of methotrexate with SJS/TEN was more significant in the entire data set when combined with furosemide than when methotrexate was not combined with furosemide. The association of methotrexate with SJS/TEN remained significant when furosemide was combined with methotrexate in a tumor-based disease context. After sensitivity analysis of the entire dataset as well as all antineoplastic drug datasets, consistent results were observed for TEN. CONCLUSIONS: Our study confirmed a significant association between methotrexate and SJS/TEN when combined with furosemide, with an increased risk of SJS/TEN.

Characterization of Shigella flexneri in northern Vietnam in 2012-2016.

Introduction: Shigellosis remains a considerable public health concern in developing countries. Shigella flexneri and Shigella sonnei are prevalent worldwide and S. sonnei has been replacing S. flexneri . Gap Statement: S. flexneri still causes outbreaks of shigellosis in northern Vietnam but limited information is available on its genetic characteristics. Aim: This study aimed to characterize the genetic characteristics of S. flexneri strains from northern Vietnam. Methodology: This study used 17 isolates from eight incidents, collected in northern Vietnam between 2012 and 2016. The samples were subjected to whole genome sequencing, molecular serotyping, cluster analysis and identification of antimicrobial resistance genes. Additionally, phylogenetic analysis was performed including isolates from previous studies. Results: Clusters were identified according to spatiotemporal backgrounds. The results suggested that two incidents in Yen Bai province in 2015 and 2016 were derived from a very recent common ancestor. All isolates belonged to phylogroup (PG) 3, which was divided into two sub-lineages. Thirteen of 17 isolates, including those from the Yen Bai incidents, belonged to sub-lineage Sub-1 and were serotyped as 1a. The remaining four isolates belonged to sub-lineage Sub-2 and were the globally predominant serotype 2a. The Sub-1 S. flexneri isolates possessed the gtrI gene, which encodes the glycosyl transferase that determines serotype 1a, with bacteriophage elements in the vicinity. Conclusion: This study revealed two PG3 sub-lineages of S. flexneri in northern Vietnam, of which Sub-1 might be specific to the region.

Molecular characterization of Cryptosporidium and Giardia in environmental samples and faecal samples from biogas users in Bac Giang, Vietnam.

Little is known about Cryptosporidium and Giardia in biogas waste and humans in Vietnam. There is a potential risk of infections during or after using the biogas system. The detected protozoan genotypes are zoonotic pathogens, and contamination of vegetables may relay through runoff to the surface waters and soil. The objective of this study was to understand the role of the environment in the epidemiology of human infections in Bac Giang province, Vietnam, with a focus on investigating the presence of Cryptosporidium spp. genotypes and Giardia assemblages among 239 environmental samples and 94 faecal samples of biogas users. PCR and sequencing analysis were used to identify the occurrence and genotypes of Cryptosporidium and Giardia in these samples. Results showed that 13/333 (3.9 %) and 9/333 (2.7 %) samples were positive for Cryptosporidium oocyst and Giardia cysts, respectively. Characterization revealed the presence of Cryptosporidium scrofarum, C. suis, C. meleagridis, C. bailey and Giardia intestinalis assemblage A and E. C. scrofarum and Giardia assemblage E were identified for the first time in humans in Bac Giang. The current information from the above investigations will be valuable for protozoan source tracking and control interventions against Cryptosporidium and Giardia infection associated with biogas wastes in Vietnam.

Genomic characterization of endemic diarrheagenic Escherichia coli and Escherichia albertii from infants with diarrhea in Vietnam.

BACKGROUND: Diarrheagenic Escherichia coli (DEC) is a group of bacterial pathogens that causes life-threatening diarrhea in children in developing countries. However, there is limited information on the characteristics of DEC isolated from patients in these countries. A detailed genomic analysis of 61 DEC-like isolates from infants with diarrhea was performed to clarify and share the characteristics of DEC prevalent in Vietnam. PRINCIPAL FINDINGS: DEC was classified into 57 strains, including 33 enteroaggregative E. coli (EAEC) (54.1%), 20 enteropathogenic E. coli (EPEC) (32.8%), two enteroinvasive E. coli (EIEC) (3.3%), one enterotoxigenic E. coli (ETEC), and one ETEC/EIEC hybrid (1.6% each), and surprisingly into four Escherichia albertii strains (6.6%). Furthermore, several epidemic DEC clones showed an uncommon combination of pathotypes and serotypes, such as EAEC Og130:Hg27, EAEC OgGp9:Hg18, EAEC OgX13:H27, EPEC OgGp7:Hg16, and E. albertii EAOg1:HgUT. Genomic analysis also revealed the presence of various genes and mutations associated with antibiotic resistance in many isolates. Strains that demonstrate potential resistance to ciprofloxacin and ceftriaxone, drugs recommended for treating childhood diarrhea, accounted for 65.6% and 41%, respectively. SIGNIFICANCE: Our finding indicate that the routine use of these antibiotics has selected resistant DECs, resulting in a situation where these drugs do not provide in therapeutic effects for some patients. Bridging this gap requires continuous investigations and information sharing regarding the type and distribution of endemic DEC and E. albertii and their antibiotic resistance in different countries.

Emergence of mobile tigecycline resistance gene tet(X4)-harbouring Shewanella xiamenensis in a water environment.

OBJECTIVES: Tigecycline resistance mediated by the mobile tigecycline-inactivating enzyme gene tet(X) in Gram-negative bacteria is an emerging concern for global public health. However, limited information is available on the distribution of tet(X) in the natural environment. In this study, we investigated the presence of tet(X) in environmental Gram-negative bacteria. METHODS: A carbapenem- and tigecycline-resistant Shewanella xiamenensis isolate (NUITM-VS1) was obtained from an urban drainage in Hanoi, Vietnam, in March 2021. Whole-genome sequencing analysis was performed by long- and short-read sequencing, resulting in a complete genome sequence. Antimicrobial resistance genes (ARGs) in the genome were detected based on the custom ARG database, including all known tigecycline resistance genes. RESULTS: Shewanella xiamenensis isolate NUITM-VS1 harboured the tet(X4) gene and the blaOXA-48 carbapenemase gene on the chromosome. tet(X4) was flanked by IS91 family transposase genes, suggesting that the acquisition of tet(X4) was mediated by this mobile gene element (MGE), whereas no MGE was found surrounding blaOXA-48, consistent with previous findings that blaOXA-48-like ß-lactamase genes are species-specific intrinsic ARGs in Shewanella spp. CONCLUSION: To the best of our knowledge, this is the first report of a tet(X4)-harbouring Shewanella sp. isolate. Our results provide genetic evidence of the complexity of the dynamics of clinically important ARGs among bacteria in the water environment.

Development of a loop-mediated isothermal amplification assay for Vibrio cholerae O1 and O139.

A loop-mediated isothermal amplification assay was developed. It was designed for recognizing Vibrio cholerae O1/O139, where atpA, rfbN, and wfbR genes were adopted. The assay specifically detected the target with sensitivities of 5-67 copies per reaction in 1 h. The assay will aid rapid detection of the cholera bacterium.

Genetic diversity of environmental Vibrio cholerae O1 strains isolated in Northern Vietnam.

Cholera epidemics have been recorded periodically in Vietnam during the seventh cholera pandemic. Since cholera is a water-borne disease, systematic monitoring of environmental waters for Vibrio cholerae presence is important for predicting and preventing cholera epidemics. We conducted monitoring, isolation, and genetic characterization of V. cholerae strains in Nam Dinh province of Northern Vietnam from Jul 2013 to Feb 2015. In this study, four V. cholerae O1 strains were detected and isolated from 110 analyzed water samples (3.6%); however, none of them carried the cholera toxin gene, ctxA, in their genomes. Whole genome sequencing and phylogenetic analysis revealed that the four O1 isolates were separated into two independent clusters, and one of them diverged from a common ancestor with pandemic strains. The analysis of pathogenicity islands (CTX prophage, VPI-I, VPI-II, VSP-I, and VSP-II) indicated that one strain (VNND_2014Jun_6SS) harbored an unknown prophage-like sequence with high homology to vibriophage KSF-1 phi and VCY phi, identified from Bangladesh and the USA, respectively, while the other three strains carried tcpA gene with a distinct sequence demonstrating a separate clonal lineage. These results suggest that the aquatic environment can harbor highly divergent V. cholera strains and serve as a reservoir for multiple V. cholerae virulence-associated genes which may be exchanged via mobile genetic elements. Therefore, continuous monitoring and genetic characterization of V. cholerae strains in the environment should contribute to the early detection of the sources of infection and prevention of cholera outbreaks as well as to understanding the natural ecology and evolution of V. cholerae.

Molecular epidemiology of Vibrio cholerae O1 in northern Vietnam (2007-2009), using multilocus variable-number tandem repeat analysis.

Cholera is an infectious disease of major concern in Vietnam and other Asian countries. In 2009, there was a large outbreak of cholera in northern Vietnam. To investigate relationships among isolates of the causative pathogen Vibrio cholerae in this region since 2007, we carried out a multilocus variable-number tandem repeat analysis (MLVA) of 170 isolates collected between 2007 and 2009. A total of 24 MLVA types were identified using seven loci. Five clones (1-5) were identified using five loci of the large V. cholerae chromosome; clones 1 and 2 were major, and the others were minor. Clone 1 isolates were responsible for the 2009 outbreak. A shift in the predominant clone occurred between 2007 and 2009, with clone 1 likely derived from clone 2. Moreover, the former was less diverse than the latter, suggesting a single source of cholera dissemination. Epidemiological data indicated a wavelet prior to the large outbreak, suggesting that drinking water source or food chain became contaminated during dissemination. Our results reveal the utility of MLVA for analysis of V. cholerae isolates within a relatively short period and broaden our understanding of its transmission and response to cholera.

Delineation of three structural Y chromosome aberrations combined molecular techniques / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To delineate the structure of Y chromosome aberrations and recombinant mechanisms for three patients.</p><p><b>METHODS</b>Karyotype analysis, multiplex ligation dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH), Y chromosome sequence tagged sites (STS) analysis, human whole genome-wide SNP array were used.</p><p><b>RESULTS</b>The karyotypes of the three patients were 46, X, +mar. As suggested by MLPA analysis, case 1 has increased copy numbers of SRY, ZFY and UTY genes, case 2 had increased copies of SRY and ZFY genes, and deletion of UTY gene, and case 3 had decreased copies for subtelomeric regions of X/Yp and X/Yq. By STSs analysis, case 1 has retained SRY, sY84 and sY86 in the AZFa region, sY1227 in the AZFb region, whilst lost sY1228 in the AZFb region and other STSs in the AZFc region. Its breakpoint was thereby mapped between sY1227 and sY1228. Case 2 has retained SRY and sY1200 in the centromeric region, whilst has deletion of other STSs. Case 3 has retained SRY and STSs in the AZF regions. By SNP array, case 1 had duplicated Yp11.31-p11.2 and deletion of Yq11.22-q11.23 (approximately 5.18 Mb). Case 2 had duplicated Yp11.31-p11.2 and deletion of Yq11.21-q11.23 (approximately 14.644 Mb). Case 3 had single copy number deletion of p22.33 and q28 in the subtelomeric region of X/Yp and X/Yq. By FISH, cases 1 and 2 showed two signals for SRY and DYZ3 but no signal for DYZ1 on their marker chromosomes. Combining above results, the karyotypes of cases 1, 2 and 3 were determined as 46, X, idic(Y) (q11.23), 46, X, idic(Y) (q10) and 46, X, r(Y) (p11q12), respectively.</p><p><b>CONCLUSION</b>Y chromosome aberrations are variable. Combined use of MLPA, STSs, FISH and SNP array is effective for revealing the breakpoints and recombinant mechanisms.</p>

Analysis of small supernumerary marker chromosome 15q11 in four infertile males / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To delineate the origins of small supernumerary marker chromosomes (sSMCs) identified in 4 infertile males.</p><p><b>METHODS</b>The sSMCs were analyzed with combined G-banding, N-banding, multiplex ligation-dependent probe amplification (MLPA), fluorescence in situ hybridization (FISH) and single nucleotide polymorphisms array (SNP-array) techniques.</p><p><b>RESULTS</b>G-banding analysis has suggested a 46,X,-Y,+mar karyotype in all of the 4 cases. N-banding revealed that all of the sSMCs have possessed two satellites located on both sides. By MLPA, 1 patient showed copy number gains for 15q11.2 region. SNP-array analysis suggested that all had duplication for 15q11.1-q11.2 region, spanning 3.06 Mb, 0.9118 Mb, 1.728 Mb and 0.287 Mb, respectively. By FISH analysis, all of the sSMCs showed two hybridization signals, indicating that they were dicentric chromosomes.</p><p><b>CONCLUSION</b>In all of the four cases, the marker chromosomes have derived from chromosome 15 and were bisatellited and dicentric, which gave rise to a karyotype of 47,XY,+ish,inv dup(15)(q11)(D15Z4++). sSMC 15q11 therefore may be a major cause for male infertility.</p>

Characterization of Vibrio cholerae O139 of an Aquatic Isolate in Northern Vietnam.

During the cholera survey in Namdinh province (northern Vietnam) in July, 2010, one strain of Vibrio cholerae O139 was isolated from 7 environmental water samples positive for ctxA, toxR,VCO139 genes and named as V. cholerae O139, ND1 strain. This strain was lysogenic harbouring a genome similar to the filamentous phage fs1. The replicative form DNA of this phage (named as ND1-fs1, 6856 bp) was sequenced and compared with the other filamentous phages. The filamentous phage ND1-fs1 integrates into the region between ctxB and rtxA genes. The genetic organization of the CTXϕ of V. cholerae O139, strain ND1 was determined and the schematic representation of the genetic organization was shown together with the ND1-fs1 prophage.

Partial AZfc region deletions of the Y chromosome in spermatogenic dysfunction patients / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the influence of partial deletions in the AZFc region of the Y chromosome on spermatogenesis.</p><p><b>METHODS</b>We selected 9 sequence tagged sites (sY1258, sY1291, sY254, sY255, sY1201, sY1206, sY1161, sY1197 and sY1191) in the AZFc region of the Y chromosome, with ZFX/ZFY and SRY (sY14) as the interior control. We amplified by multiplex PCR the DNA of 160 patients with azoospermia or severe oligozoospermia that showed no microdeletion of the Y chromosome (the case group) and another 76 males with normal fertility (the control group). For the individuals suspected of DAZ gene deletion, we detected the single nucleotide polymorphism sites (SNPs) in the four copies of the DAZ gene by single nucleotide variation (SNV) analysis to determine the types of DAZ copy deletion.</p><p><b>RESULTS</b>In the case group, there were 10 cases of gr/gr (sY1291) deletion (6.3%), 14 b2/b3 (sY1191) deletion (8.8%), 1 sY1291,sY1197 deletion (0.6%), 1 b1/b2 deletion (0.6%) and 1 b1/b3 deletion (0.6%), while in the control group, there were 4 cases of gr/gr deletion (5.3%) and 4 b2/b3 deletion (5.3%). SNV analysis showed DAZ1/DAZ2 deletion in all those with gr/gr and those with b1/b3 deletion, DAZ3/DAZ4 deletion in those with b2/b3 deletion, and DAZ-SNV sY587 deletion in 1 case of sY1291, sY1197 deletion, but no DAZ deletion was found in 1 case of b1/b2 deletion.</p><p><b>CONCLUSION</b>B2/b3 (sY1191) and gr/gr (sY1291) deletions are genomic polymorphisms and quite common in the normal Chinese population; while b1/b2, b1/b3, and sY1291, sY1197 deletions may be high risk factors of dyszoospermia.</p>

Two different mechanisms of ampicillin resistance operating in strains of Vibrio cholerae O1 independent of resistance genes.

Autoagglutinable strains of Vibrio cholerae O1 (seven nonfimbriate strains and one fimbriate strain) were transformed to obtain resistance to ampicillin. Two distinct mechanisms were found in these strains. One was operating in nonfimbriate strains by reducing OmpU protein production and the other was operating in a fimbriate strain (Bgd17) by newly overproducing cpxP protein. The twitching motility in the fimbriate Bgd17 strain disappeared depending on the production of cpxP protein, suggesting that fimbriation of V. cholerae O1 is controlled by a two-component signal transduction system.

Filamentous vibriophage fs2 encoding the rstC gene integrates into the same chromosomal region as the CTX phage [corrected].

The genome of the filamentous phage of Vibrio cholerae fs2 was found to contain rstC and rstB1 (truncated) genes downstream of ORF500. att-fs2-dir and att-fs2-rev sequences homologous to that of att-CTXphi were found between orf500 and rstC of the fs2 genome. This prompted us to search for the integration site of fs2 in the genomes of V. cholerae O1 and O139. The genome of fs2 was found to integrate downstream of attRS of the CTXphi phage, which integrated into chromosome I of V. cholerae O1 and O139. When infected with fs2, a fimbriate strain of V. cholerae O1 appeared to reduce fimbrial production in an adult rabbit ileal loop assay.

Prenatal diagnosis of 5 fetuses with high risk of developing spinal muscular atrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To perform prenatal diagnosis for 5 pregnant women who had given birth to children with spinal muscular atrophy (SMA).</p><p><b>METHODS</b>Thirty to forty mililiters of amniotic fluid was obtained by amniocentesis under ultrasonic monitoring. DNA was extracted directly from sediment of amniotic fluid. Short tandem repeat (STR) profiling was carried out to evaluate the contamination of amniotic DNA by maternal genomic DNA. Two methods, PCR-restriction fragment length polymorphism (PCR-RFLP) and allele-specific PCR, were used to analyze exon 7 of SMN gene from amniotic DNA.</p><p><b>RESULTS</b>Comparing the 16 STR sites of each fetus with those of his/her parents, there was no or little contamination of amniotic DNA by maternal genomic DNA. In conventional PCR-RFLP, part of the PCR product (189 bp) from amniotic DNA of fetus A, C, or D remained intact after digestion with Dra I, while the PCR product from amniotic DNA of fetus B or E was completely digested by Dra I. In allele-specific PCR, exon 7 of both SMN1 and SMN2 gene could be seen when amniotic DNA of fetuses A, C, or D was analyzed, while only exon 7 of SMN2 could be seen when amniotic DNA of fetuses B or E was analyzed.</p><p><b>CONCLUSION</b>Homozygous deletion of SMN1 is not detected in fetuses A, C, and D, predicting that the risk of developing SMA after birth would be extremely low. Homozygous deletion of SMN1 was present in fetuses B and E suggesting high risk of developing SMA after birth.</p>

Prenatal molecular diagnosis of adrenoleukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To carry out prenatal diagnosis on two fetuses of different pedigrees with X-linked adrenoleukodystrophy (ALD).</p><p><b>METHODS</b>The amniotic fluid was obtained with the help of a clinical doctor and the genomic DNA was isolated from it. Maternal DNA contamination was excluded by fluorescent STR profiling, The R617G mutation found in the first pedigree was searched in genomic DNA of amniotic fluid cells (AFC) from fetus 1 by amplification refractory mutation system (ARMS) and dot DNA hybridization while the P534R mutation found in pedigree 2 was analyzed in the AFC genomic DNA of fetus 2 by restrictive digestion with Hae II and DNA direct sequencing.</p><p><b>RESULTS</b>A specific band (185 bp) was detected from the genomic DNA of the first fetus and his mother by using mutation primer in ARMS but not from that of the first fetus's father and unrelated controls. DNA dots were visualized only in the fetus 1 and carrier when using the mutation probe in DNA hybridization. In the other ALD family, the PCR product (506 bp) of the second fetus which spanned the site of P534R mutation could not be digested with Hae II and no mutation was detected in the ABCD1 gene from the genomic DNA of the fetus 2 by using DNA direct sequencing.</p><p><b>CONCLUSION</b>Fetus 1 had R617G mutation on his ABCD1 gene and he was an adrenoleukodystrophy hemizygote. Fetus 2 had no P534R mutation on his ABCD1 gene and he was a normal hemizygote.</p>