Molecular Epidemiological Characteristics Research Articles

Epidemiological characteristics of human metapneumovirus among children in Nanjing, China.

The objective of this study was to examine the molecular epidemiology and clinical characteristics of HMPV infection among children with ARIs in Nanjing. The respiratory samples were collected from 2078 children (≤ 14 years) with acute respiratory infections and were tested for HMPV using real-time RT-PCR. Amplification and sequencing of the HMPV G gene were followed by phylogenetic analysis using MEGA 7.0. The detection rate of HMPV among children was 4.7% (97/2078), with a concentration in those under 5 years of age. Notably, the peak season for HMPV prevalence was observed in winter. Among the 97 HMPV-positive samples, 51.5% (50/97) were available for characterization of the HMPV G protein gene. Phylogenetic analysis indicated that the sequenced HMPV strains were classified into three sublineages: A2c111nt - dup (84.0%), B1 (2.0%), and B2 (14.0%). There was an incidence of HMPV among hospitalized children during 2021-2022 in Nanjing with A2c111nt - dup being the dominant strain. This study demonstrated the molecular epidemiological characteristics of HMPV among children with respiratory infections in Nanjing, China.

First report of molecular epidemiology and phylogenetic characteristics of feline herpesvirus (FHV-1) from naturally infected cats in Kunshan, China

BackgroundFeline herpesvirus type 1 (FHV-1) is a life threatening highly contagious virus in cats and typically causes upper respiratory tract infections as well as conjunctival and corneal ulcers. Genetic variability could alter the severity of diseases and clinical signs. Despite regular vaccine practices against FHV-1 in China, new FHV-1 cases still commonly occur. The genetic and phylogenetic characteristics of FHV-1 in Kunshan city of China has not been studied yet. Therefore, this study was planned to investigate the prevalence, molecular characteristics of circulating strains, and phylogenetic analyses of FHV-1. This is the first report of molecular epidemiology and phylogenetic characteristics of FHV-1 from naturally infected cats in Kunshan, China.MethodsThe occulo-nasal swabs were collected from diseased cats showing respiratory distress, conjunctivitis, and corneal ulcers at different veterinary clinics in Kunshan from 2022 to 2023. Clinical data and general information were recorded. Swab samples were processed for preliminary detection of FHV-1. Thymidine kinase (TK), glycoprotein B (gB) and glycoprotein D (gD) genes were sequenced and analyzed to investigate genetic diversity and evolution of FHV-1.ResultsThe FHV-1 genome was detected in 43 (43/200, 21.5%) samples using RT-PCR targeting the TK gene. Statistical analysis showed a significant correlation between age, vaccination status and living environment (p < 0.05) with FHV-1 positivity, while a non-significant correlation was observed for FHV-1 positivity and sex of cats (p > 0.05). Additionally, eight FHV-1 positive cats were co-infected with feline calicivirus (8/43,18.6%). FHV-1 identified in the present study was confirmed as FHV-1 based on phylogenetic analyses. The sequence analyses revealed that 43 FHV-1 strains identified in the present study did not differ much with reference strains within China and worldwide. A nucleotide homology of 99-100% was determined among gB, TK and gD genes nucleotide sequences when compared with standard strain C-27 and vaccine strains. Amino acid analysis showed some amino acid substitutions in TK, gB and gD protein sequences. A potential N-linked glycosylation site was observed in all TK protein sequences. Phylogenetic analyses revealed minor variations and short evolutionary distance among FHV-1 strains detected in this study.ConclusionsOur findings indicate that genomes of 43 FHV-1 strains are highly homogenous and antigenically similar, and the degree of variation in major envelope proteins between strains is low. This study demonstrated some useful data about prevalence, genetic characteristics, and evolution of FHV-1 in Kunshan, which may aid in future vaccine development.

Epidemiological and clinical characterization of community, healthcare-associated and nosocomial colonization and infection due to carbapenemase-producing Klebsiella pneumoniae and Escherichia coli in Spain.

Community-acquired (CA) and healthcare-associated (HCA) infections caused by carbapenemase-producing Enterobacterales (CPE) are not well characterized. The objective was to provide detailed information about the clinical and molecular epidemiological features of nosocomial, HCA and CA infections caused by carbapenemase-producing Klebsiella pneumoniae (CP-Kp) and Escherichia coli (CP-Ec). A prospective cohort study was performed in 59 Spanish hospitals from February to March 2019, including the first 10 consecutive patients from whom CP-Kp or CP-Ec were isolated. Patients were stratified according to acquisition type. A multivariate analysis was performed to identify the impact of acquisition type in 30-day mortality. Overall, 386 patients were included (363 [94%] with CP-Kp and 23 [6%] CP-Ec); in 296 patients (76.3%), the CPE was causing an infection. Acquisition was CA in 31 (8.0%) patients, HCA in 183 (47.4%) and nosocomial in 172 (48.3%). Among patients with a HCA acquisition, 100 (54.6%) had been previously admitted to hospital and 71 (38.8%) were nursing home residents. Urinary tract infections accounted for 19/23 (82.6%), 89/130 (68.5%) and 42/143 (29.4%) of CA, HCA and nosocomial infections, respectively. Overall, 68 infections (23%) were bacteremia (8.7%, 17.7% and 30.1% of CA, HCA and nosocomial, respectively). Mortality in infections was 28% (13%, 14.6% and 42.7% of CA, HCA and nosocomial, respectively). Nosocomial bloodstream infections were associated with increased odds for mortality (adjusted OR, 4.00; 95%CI 1.21-13.19). HCA and CA infections caused by CPE are frequent and clinically significant. This information may be useful for a better understanding of the epidemiology of CPE.

Clonal transmission of blaIMP-4-carrying ST196 Klebsiella pneumoniae isolates mediated by IncN plasmid in China

ObjectivesTo investigate the clinical and molecular epidemiological characteristics of blaIMP-4-carrying Klebsiella pneumoniae in a tertiary hospital in China. Methods10 Carbapenem Resistant K. pneumoniae (CRKP) isolates with blaIMP-4 gene were collected. Molecular characteristics were analyzed using whole-genome sequencing. Plasmid conjugation experiment was used to analyze the conjugation of plasmids. We compared and analyzed K. pneumoniae carrying blaIMP-4 on NCBI with the strains in this study. ResultsAll 10 CRKP isolates with blaIMP-4 were collected from 10 adult patients in the respiratory intensive care unit. These strains were only sensitive to polymyxins and tigecycline due to simultaneously carrying multiple resistance genes, such as blaOKP-A-5, fosA, oqxA and oqxB. Notably, R29 harbored two carbapenemase genes (blaNDM-1 and blaIMP-4). These strains had similar drug-resistant phenotypes and drug-resistant genes, all belonging to ST196. Additionally, the patients had spatiotemporal intersection during hospitalization, suggesting that these strains had clonal transmission, but they belonged to different clonal clusters from the blaIMP-4-positive K. pneumoniae currently published on NCBI. Among the 10 strains, blaIMP-4 was located on the IncN plasmid, and 6 strains had successfully transferred the plasmid to the recipient strain EC600 through plasmid conjugation. ConclusionsThe blaIMP-4-positive ST196 CRKP had clonal distribution in the respiratory ICU, which was mediated by IncN plasmid. Consequently, there should be increased monitoring of carbapenem-resistant strains in clinical settings to prevent and control of its transmission.

Hepatitis C virus subtype diversity and transmission clusters characteristics among drug users in Zhuhai, South China

BackgroundHepatitis C virus (HCV) infection poses a major public health challenge globally, especially among injecting drug users. China has the world’s largest burden of HCV infections. However, little is known about the characteristics of transmission networks among drug user populations. This study aims to investigate the molecular epidemiology and transmission characteristics of HCV infections among drug users in Zhuhai, a bustling port city connecting Mainland China and its Special Administrative Regions.MethodsParticipants enrolled in this study were drug users incarcerated at Zhuhai’s drug rehabilitation center in 2015. Their sociodemographic and behavioral information, including gender, promiscuity, drug use method, and so forth, was collected using a standardized questionnaire. Plasmas separated from venous blood were analyzed for HCV infection through ELISA and RT-PCR methods to detect anti-HCV antibodies and HCV RNA. The 5’UTR fragment of the HCV genome was amplified and further sequenced for subtype identifications and phylogenetic analysis. The phylogenetic tree was inferred using the Maximum Likelihood method based on the Tamura-Nei model, and the transmission cluster network was constructed using Cytoscape3.8.0 software with a threshold of 0.015. Binary logistic regression models were employed to assess the factors associated with HCV infection.ResultsThe overall prevalence of HCV infection among drug users was 44.37%, with approximately 19.69% appearing to clear the HCV virus successfully. Binary logistic regression analysis revealed that those aged over 40, engaging in injecting drug use, and being native residents were at heightened risk for HCV infection among drug user cohorts. The predominant HCV subtypes circulating among those drug users were 6a (60.26%), followed by 3b (16.7%), 3a (12.8%), 1b (6.41%) and 1a (3.85%), respectively. Molecular transmission network analysis unveiled the presence of six transmission clusters, with the largest propagation cluster consisting of 41 individuals infected with HCV subtype 6a. Furthermore, distinct transmission clusters involved eight individuals infected with subtype 3b and seven with subtype 3a were also observed.ConclusionThe genetic transmission networks revealed a complex transmission pattern among drug users in Zhuhai, emphasizing the imperative for a targeted and effective intervention strategy to mitigate HCV dissemination. These insights are pivotal for shaping future national policies on HCV screening, treatment, and prevention in port cities.

Genetic Diversity of Blastocystis in Diarrheal Cases: Identification of Subtypes and Alleles

Blastocystis spp. are the most common intestinal protozoan parasites detected in human stool samples. While identified long before today, its pathogenicity remains controversial. It is generally asymptomatic but in symptomatic cases, many gastrointestinal symptoms, especially diarrhea, have been associated with Blastocystis infection. In recent years, the relationship between the symptoms observed in cases and Blastocystis subtypes (ST) has been reported. The aim of this study was to detect Blastocystis in diarrheal cases admitted to the Aydın Adnan Menderes University Faculty of Medicine, Department of Parasitology Laboratory, to determine subtypes and allele diversity and to investigate its relationship with clinical symptoms. For this purpose, diarrheal stool samples of 200 cases were included in the study and their demographic characteristics (age, gender, residence) and clinical findings (abdominal pain, dyspepsia, nausea-vomiting, weakness, weight loss, anal itching, rash, urticaria) were recorded. Blastocystis was detected by direct microscope method (DM) and by molecular analyses which were performed with polymerase chain reaction (PCR). Subtype diversity was determined based on DNA sequence analysis by PCR targeting the Blastocystis ribosomal ribonucleic acid small subunit (SSU rRNA) gene. In addition, alleles related to Blastocystis subtypes were determined and statistically compared between all data and clinical findings. In the current study, Blastocystis was detected in 31 (15.5%) samples by DM and in 35 (17.5%) samples by PCR specific to the Blastocystis SSU rRNA gene among 200 diarrheal stool samples. No statistical difference was detected between Blastocystis and demographic characteristics. Dyspepsia and nausea-vomiting symptoms differed significantly in cases with Blastocystis compared to negative ones (p= 0.0025, p= 0.0498). Blastocystis subtype was detected in 33 samples by SSU rRNA sequence analysis, and the subtype distribution was ST1 (n= 10, 30.3%), ST2 (n= 4, 12.1%) and ST3 (n= 19, 57.6%). In the statistical evaluation between clinical findings and Blastocystis subtypes, a relationship was found between dyspepsia and Blastocystis ST3 (p= 0.0039). The allele diversity of Blastocystis subtypes was determined as allele 4 (10/10) in all ST1, allele 11 (2/4) and 12 (2/4) in ST2, allele 34 (14/19), 36 (4/19), and 38 (1/19) in ST3. In conclusion, our study provides important data on the molecular epidemiological characteristics of the Blastocystis by determining positivity, subtypes and alleles in diarrheal cases. Therefore, within the scope of the one health approach, comprehensive molecular epidemiological studies are required to determine the presence and genotypes of Blastocystis in human, animal and environmental samples.

Molecular epidemiological and clinical infection characteristics analysis of Ralstonia.

This study was to clarify the molecular epidemiology and clinical infection characteristics of Ralstonia pickettii and establish sequence typing system. 48 nonrepetitive Ralstonia pickettii strains were collected from January 2008 to December 2013 at the Chinese People's Liberation Army General Hospital (PLAGH) and were identified through a specific PCR experiment, 16S rDNA experiment and VITEK 2 system to compare the identification accuracy. The sequence types of the strains were analyzed by multilocus sequence typing (MLST) method. The antibiotic sensitivity of these strains was determined with disc diffusion tests and broth microdilution method. The clinical data of Ralstonia pickettii infected patients were collected. All of the 48 strains were identified as Ralstonia pickettii by VITEK 2 system. 30 and 34 strains were identified as Ralstonia pickettii by PCR and 16S rDNA experiment respectively. ST9 was the most sequence types (STs) in these 18 STs of 42 strains. 42 strains were divided into 2 groups (A and B) and 18 genotypes. Ralstonia pickettii was sensitive to some cephalosporins, β-lactam/β-lactamase inhibitor, levofloxacin and trimethoprim/sulfamethoxazole. Cough, sputum, shortness of breath and pulmonary rales were the common clinical symptoms of most Ralstonia pickettii infected patients. We established a sequence typing system with a relatively fine resolution and the PCR assay is a faster and more sensitive method for clinical identification of Ralstonia pickettii. ST9 is the most common sequence types of Ralstonia pickettii. The most common clinical characteristics of Ralstonia pickettii infected patients were cough, sputum, shortness of breath and pulmonary rales.

Genomic characterization and outbreak investigations of methicillin-resistant Staphylococcus aureus in a county-level hospital in China.

Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen contributing to healthcare-associated infections, which can result in multiple sites infections. The epidemiological characteristics of MRSA exhibit variability among distinct regions and healthcare facilities. The aim of this study was to investigate the molecular epidemiology and nosocomial outbreak characteristics of MRSA in a county-level hospital in China. A total of 130 non-repetitive MRSA strains were collected from December 2020 to November 2021. Whole-genome sequencing (WGS) was performed to identify antimicrobial resistance and virulence factors. Phylogenetic analysis was conducted to ascertain genetic diversity and phylogenetic relationships. Independent transmission scenarios were determined by the phylogeny derived from single nucleotide polymorphisms (SNPs) within the core genome. All the MRSA isolates were collected from the intensive care unit (30.00%, 39/130), the department of otorhinolaryngology (10.00%, 13/130) and the department of burn unit (9.23%, 12/130). The clinical samples mainly included phlegm (53.85%, 70/130), purulent fluid (24.62%, 32/130), and secretions (8.46%, 11/130). The resistance rates to erythromycin, clindamycin and ciprofloxacin were 75.38, 40.00, and 39.23%, respectively. All the isolates belonged to 11 clonal complexes (CCs), with the major prevalent types were CC5, CC59, and CC398, accounting for 30.00% (39/130), 29.23% (38/130), and 16.92% (22/130), respectively. Twenty sequence types (STs) were identified, and ST59 (25.38%, 33/130) was the dominant lineage, followed by ST5 (23.84%, 31/130) and ST398 (16.92%, 22/130). Three different SCCmec types were investigated, most of isolates were type IV (33.85%, 44/130), followed by type II (27.69%, 36/130) and type III (0.77%, 1/130). The common clonal structures included CC5-ST5-t2460-SCCmec IIa, CC59-ST59-t437-SCCmec IV and CC398-ST398-t034-SCCmec (-), with rates of 16.92% (22/130), 14.62% (19/130), and 13.84% (18/130), respectively. Only 12 panton-valentine leucocidin (PVL) positive strains were identified. Two independent clonal outbreaks were detected, one consisting of 22 PVL-negative strains belongs to CC5-ST5-t2460-SCCmec IIa and the other consisting of 8 PVL-negative strains belongs to CC5-ST5-t311-SCCmec IIa. Overall, our study indicated that the CC5 lineage emerged as the predominant epidemic clone of MRSA, responsible for nosocomial outbreaks and transmission within a county-level hospital in China, highlighting the necessity to strengthen infection control measures for MRSA in such healthcare facilities.

Molecular detection and genotyping of Dientamoeba fragilis and Blastocystis sp. in housefly Musca domestica (Diptera: Muscidae): first report for Dientamoeba fragilis.

Dientamoeba fragilis and Blastocystis sp. are single-celled protozoan parasites of humans and animals. Although they are found in the intestines of healthy hosts, the pathogenicity of them is still unclear. To date, there is no report on D. fragilis and only two studies (without subtyping) on the occurrence of Blastocystis sp. in Musca domestica. In this study, fly samples were collected from livestock farms and their surroundings in the Kirsehir province (Central Anatolia Region) of Türkiye from May to August 2023. A total of 150 microscopically identified M. domestica samples were analyzed for the detection of D. fragilis and Blastocystis sp. molecularly. The overall prevalence of Blastocystis sp. and D. fragilis in M. domestica was determined to be 3.3% (5/150) and 8.0% (12/150), respectively. The SSU rRNA gene sequences of the isolates indicated genotype 1 of D. fragilis. Eleven isolates were identical and represented a single isolate (KAU-Dfrag1). BLAST analysis of KAU-Dfrag1 indicated identity with the isolates reported from humans, cattle, sheep, and budgerigars. The other isolate (KAU-Dfrag2) was polymorphic at two nucleotides from KAU-Dfrag1 and three nucleotides from known genotypes from GenBank and represented a variant of genotype 1. The Blastocystis sp. isolates were found to be identical and represent a single genotype (KAU-Blast1). BLAST analysis revealed that the KAU-Blast1 genotype belonged to the potentially zoonotic subtype 5 (ST5) and exhibited the highest genetic identity (ranging from 99.4 to 99.6%) with pigs, cattle, and sheep from different countries. Our study provides the first data on the molecular prevalence, epidemiology, and genotypic characterization of D. fragilis and Blastocystis sp. in M. domestica.

Molecular Epidemiology and Clinical Characteristics of an Outbreak on Respiratory Virus Coinfection in Gansu, China.

This study aims to analyze the epidemiological and pathogenic characteristics of an outbreak primarily caused by respiratory syncytial virus (RSV), human rhinovirus (HRV), and human metapneumovirus (HMPV) in a kindergarten and primary school. The outbreak was investigated by field epidemiological investigation, and the common respiratory pathogens were screened by RT-PCR detection technology. The attack rate of this outbreak was 63.95% (110/172). Main symptoms included cough (85.45%), sore throat (60.91%), and sneezing (60.00%). Multifactorial logistic regression analysis revealed that continuous handwashing and mouth and nose covering when sneezing were protective factors. All 15 collected throat swab specimens tested positive for viruses, with HMPV as the predominant pathogen (80.00%), followed by HRV (53.33%), and two cases of positive respiratory syncytial virus (13.33%). Among them, six samples showed coinfections of HMPV and HRV, and one had coinfections of HMPV and RSV, resulting in a coinfection rate of 46.67%. Genetic sequencing indicated that the HMPV genotype in this outbreak was A2c, and the HRV genotype was type A, resulting in a coinfection outbreak of HMPV, HRV, and RSV in schools and kindergartens, suggesting that multi-pathogen surveillance of respiratory tract infections should be strengthened.

Molecular epidemiology and phylogenetic analysis of feline calicivirus in Kunshan, China

Feline calicivirus (FCV) is a highly contagious virus in cats, which typically causes respiratory tract and oral infections. Despite vaccination against FCV being a regular practice in China, new FCV cases still occur. Antigenic diversity of FCV hinders the effective control by vaccination. This is first report which aims to investigate the molecular epidemiology and molecular characteristics of FCV in Kunshan, China. The nasopharyngeal swabs were collected from cats showing variable clinical signs from different animal clinics in Kunshan from 2022 to 2023. Preliminary detection and sequencing of the FCV capsid gene were performed to study genetic diversity and evolutionary characteristics. FCV-RNA was identified in 52 (26%) of the samples using RT-PCR. A significant association was found between FCV-positive detection rate, age, gender, vaccination status and living environment, while a non-significant association was found with breed of cats. Nucleotide analysis revealed two genotypes, GI and GII. GII predominated in Kunshan, with diverse strains and amino acid variations potentially affecting vaccination efficacy and FCV detection. Notably, analysis pinpointed certain strains’ association with FCV-virulent systemic disease pathotypes. This investigation sheds light on FCV dynamics, which may aid in developing better prevention strategies and future vaccine designs against circulating FCV genotypes.

Molecular epidemiological characteristics of osteoarthritis-associated Brucella melitensis in China: evidence from whole-genome sequencing-based analysis

BackgroundBrucellosis, developing complications including arthritis, spondylitis, sacroiliitis, and osteomyelitis, is one of the most common zoonotic diseases in the current world which causes economic losses to the livestock industry and is a great public health concern. Brucella melitensis are the main pathogen of brucellosis epidemics in China, most of which are located in northern China. However, there is limited knowledge about the epidemiology of osteoarthritis-associated brucellosis. This study was aimed to reveal the prevalence of osteoarthritis-associated brucellosis in Inner Mongolia and also to investigate the molecular characteristics of B. melitensis isolates.Methods and resultsIn 2018, the osteoarthritis symptoms of brucellosis in the Brucellosis department of a hospital in Inner Mongolia were investigated. Twenty osteoarthritis-associated B. melitensis strains, isolated from the inpatients in Inner Mongolia during 2013–2017, were subjected to whole genome sequencing. The multilocus sequence type (MLST) and core genome SNP (cgSNP) analysis were conducted to detect molecular epidemiological characteristics. The incidence of brucellosis osteoarthritis symptoms in males (85/120, 70.8%) was significantly higher than that in females (35/120, 29.2%), and the age of patients was concentrated between 41 and 60 years old. In silico analyses indicated ST8 was the prevalent sequence type and the transmission of osteoarthritis-associated B. melitensis among different geographical areas. All strains carry virulence genes, including cgs, lpsA, manCoAg, pgm, pmm, virB4, wbdA and wboA.ConclusionOur study showed the close epidemiologically connection of osteoarthritis-associated B. melitensis strains in northern China. And ST8 was the prevalent sequence type which need our attention.

Antibiotic resistance, biofilm formation, and molecular epidemiology of Staphylococcus aureus in a tertiary hospital in Xiangyang, China.

Staphylococcus aureus is a common clinical pathogen that causes various human infections. The aim of this study was to investigate the antibiotic susceptibility pattern, molecular epidemiological characteristics, and biofilm formation ability of S. aureus isolates from clinical specimens in Xiangyang and to analyze the correlation among them. A total of 111 non-duplicate S. aureus isolates were collected from the Affiliated Hospital of Hubei University of Arts and Science. All isolates were tested for antibacterial susceptibility. Methicillin-resistant S. aureus (MRSA) was identified by the mecA gene PCR amplification. All isolates were analyzed to determine their biofilm-forming ability using the microplate method. The biofilm-related gene was determined using PCR. SCCmec, MLST, and spa types of MRSA strains were performed to ascertain the molecular characteristics. Among the 111 S. aureus isolates, 45 (40.5%) and 66 (59.5%) were MRSA and MSSA, respectively. The resistance of MRSA strains to the tested antibiotics was significantly stronger than that of MSSA strains. All isolates were able to produce biofilm with levels ranging from strong (28.9%, 18.2%), moderate (62.2%, 62.1%), to weak (8.9%, 19.7%). Strong biofilm formation was observed in MRSA strains than in MSSA strains, based on percentages. There were dynamic changes in molecular epidemic characteristics of MRSA isolates in Xiangyang. SCCmecIVa-ST22-t309, SCCmecIVa-ST59-t437, and SCCmecIVa-ST5-t2460 were currently the main epidemic clones in this region. SCCmecIVa-ST5-t2460 and SCCmecIVa/III-ST22-t309 have stronger antibiotic resistance than SCCmecIVa-ST59-t437 strains, with resistance to 6 ~ 8 detected non-β-lactam antibiotics. The molecular epidemic and resistance attributes of S. aureus should be timely monitored, and effective measures should be adopted to control the clinical infection and spread of the bacteria.

Genomic Surveillance Uncovers a 10-Year Persistence of an OXA-24/40 Acinetobacter baumannii Clone in a Tertiary Hospital in Northern Spain.

Infections caused by carbapenem-resistant Acinetobacter baumannii are a global threat causing a high number of fatal infections. This microorganism can also easily acquire antibiotic resistance determinants, making the treatment of infections a big challenge, and has the ability to persist in the hospital environment under a wide range of conditions. The objective of this work was to study the molecular epidemiology and genetic characteristics of two blaOXA24/40Acinetobacter baumannii outbreaks (2009 and 2020-21) at a tertiary hospital in Northern Spain. Thirty-six isolates were investigated and genotypically screened by Whole Genome Sequencing to analyse the resistome and virulome. Isolates were resistant to carbapenems, aminoglycosides and fluoroquinolones. Multi-Locus Sequence Typing analysis identified that Outbreak 1 was mainly produced by isolates belonging to ST3Pas/ST106Oxf (IC3) containing blaOXA24/40, blaOXA71 and blaADC119. Outbreak 2 isolates were exclusively ST2Pas/ST801Oxf (IC2) blaOXA24/40, blaOXA66 and blaADC30, the same genotype seen in two isolates from 2009. Virulome analysis showed that IC2 isolates contained genes for capsular polysaccharide KL32 and lipooligosacharide OCL5. A 8.9 Kb plasmid encoding the blaOXA24/40 gene was common in all isolates. The persistance over time of a virulent IC2 clone highlights the need of active surveillance to control its spread.

Clinical and molecular epidemiological features of critically ill patients with invasive group A Streptococcus infections: a Belgian multicenter case-series

BackgroundRecent alerts have highlighted an increase in group A streptococcal (GAS) infections since 2022 in Europe and the United States. Streptococcus pyogenes can cause limited skin or mucosal disease, but can also present as severe invasive disease necessitating critical care. We performed a multicenter retrospective study of patients with GAS infections recently admitted to Belgian intensive care units (ICUs) since January 2022. We describe patient characteristics and investigate the molecular epidemiology of the S. pyogenes strains involved.ResultsBetween January 2022 and May 2023, a total of 86 cases (56 adults, 30 children) with GAS disease were admitted to critical care in the university hospitals of Leuven, Antwerp and Liège. We noted a strikingly high incidence of severe community-acquired pneumonia (sCAP) (45% of adults, 77% of children) complicated with empyema in 45% and 83% of adult and pediatric cases, respectively. Two-thirds of patients with S. pyogenes pneumonia had viral co-infection, with influenza (13 adults, 5 children) predominating. Other disease presentations included necrotizing fasciitis (23% of adults), other severe skin/soft tissue infections (16% of adults, 13% of children) and ear/nose/throat infections (13% of adults, 13% of children). Cardiogenic shock was frequent (36% of adults, 20% of children). Fifty-six patients (65%) had toxic shock syndrome. Organ support requirements were high and included invasive mechanical ventilation (77% of adults, 50% of children), renal replacement therapy (29% of adults, 3% of children) and extracorporeal membrane oxygenation (20% of adults, 7% of children). Mortality was 21% in adults and 3% in children. Genomic analysis of S. pyogenes strains from 55 out of 86 patients showed a predominance of emm1 strains (73%), with a replacement of the M1global lineage by the toxigenic M1UK lineage (83% of emm1 strains were M1UK).ConclusionsThe recent rise of severe GAS infections (2022–23) is associated with introduction of the M1UK lineage in Belgium, but other factors may be at play—including intense circulation of respiratory viruses and potentially an immune debt after the COVID pandemic. Importantly, critical care physicians should include S. pyogenes as causative pathogen in the differential diagnosis of sCAP.

Molecular Characteristics of Staphylococcus aureus Isolates form Food-Poisoning Outbreaks (2011-2022) in Sichuan, China.

Staphylococcal food poisoning (SFP) is one of the most common foodborne diseases in the world. This study aimed to investigate the molecular epidemiological characteristics of Staphylococcus aureus isolated from SFP. A total of 103 S. aureus isolates were obtained during 2011-2022 in Sichuan, southwest China. All isolates were tested for the genomic characteristics and phylogenetic analysis by performing whole-genome sequencing. Multilocus sequence typing analysis showed 17 multilocus sequence types (STs), ST7 (23.30%), ST5 (22.33%), and ST6 (16.50%) being the most common. A total of 45 virulence genes were detected, 22 of which were staphylococcal enterotoxin (SE) genes. Among the identified SE genes, selX exhibited the highest prevalence (86.4%). All isolates carried at least one SE gene. The results of the antimicrobial resistance (AMR) gene detection revealed 41 AMR genes of 12 classes. β-lactam resistance genes (blal, blaR1, blaZ) and tetracycline resistance gene (tet(38)) exhibited a higher prevalence rate. Core genome single nucleotide polymorphism showed phylogenetic clustering of the isolates with the same region, year, and ST. The results indicated that the SFP isolates in southwest of China harbored multiple toxin and resistance genes, with a high prevalence of new SEs. Therefore, it is important to monitor the antimicrobial susceptibility and SE of S. aureus to reduce the potential risks to public health.

The role of recombination variability to the formation of the population the HIV‐1 population circulating in the Primorsky Krai, Russia

Aim. To research the molecular epidemiological features of the territorial spread of HIV infection and the influence of recombination variability on the formation of the HIV‐1 population in the Primorsky Krai, Russia. Materials and Methods. A comprehensive analysis of the molecular genetic characteristics of HIV‐1 and clinical‐epidemiological data of 127 HIV‐infected residents of Primorsky Krai was performed. The nucleotide sequences of the pol gene region encoding protease, reverse transcriptase and integrase of HIV‐1 were obtained by the sequencing of amplified fragments of the virus. Genotyping, phylogenetic, and mutational analyses were performed using specialised software resources. Results. In the samples studied of HIV‐1 isolated in the Primorsky Krai, the dominance of HIV‐1 subtype A6 was detected as 40.9 %. The prevalence of subtype B viruses is high compared to other Russian regions – 29.9 %. The HIV‐1 subtype C was found in 6.3 % of the samples studied; circulating recombinant forms CRF63_02A6 – 6.3 %, CRF02_AG – 0.8 %. Unique viruses resulting from the recombination of HIV subtypes A6 and B, A6 and C, C and B were found in 15.7 % of cases (URF_A6C, URF_CB, URF_BA6). Of the 18 HIV‐1 URFs described, 14 were variants of URF_A6C (11 %). Analysis of the near full‐length genome (NFLG) of URF_A6C made it possible to find and describe a new HIV genovariant spreading in Primorye ‐ CRF157_A6C. Conclusion. The analysis of HIV‐1 circulating in the Primorsky Krai confirmed that a specific molecular epidemic situation is developing in the region, which is characterized by active transmission of viruses not only of subtype A6, but also of subtypes B and C, which is not observed in other regions of Russia. For the first time in the Far East, a high frequency of HIV‐1 new unique recombinant forms occurrence has been described, some variants of which are beginning to spread among residents of the Primorsky Krai. An increase in the genetic heterogeneity of the viral population due to recombination variability of HIV is a negative prognostic factor for the territorial epidemic progress of HIV infection in the Far East.

Molecular epidemiology and clinical characteristics of respiratory syncytial virus in hospitalized children during winter 2021-2022 in Bengbu, China.

This study aimed to study the molecular epidemiology and clinical characteristics of respiratory syncytial virus (RSV) infection from hospitalized children with ARTI in Bengbu. One hundred twenty-four nasopharyngeal swab specimens and clinical data from children with ARTI cases were collected in Bengbu, China, during winter 2021-2022. The samples were detected by qPCR of 13 respiratory viruses. Phylogenetic analysis was constructed using MEGA 7.0. All analyses were performed using SAS software, version 9.4. In winter 2021-2022, URTI, NSCAP, SCAP, and bronchiolitis accounted for 41.03%, 27.35%, 17.09%, and 14.53% of hospitalized children in Bengbu, China. The detection rates of the top three were RSV (41.94%), ADV (5.65%), and FluB (5.65%) in hospitalized children through 13 virus detection. RSV is the main pathogen of hospitalized children under 2 years old. Forty-eight sequences of G protein of RSV were obtained through PCR amplification, including RSV-A 37 strains and RSV-B 11 strains. Phylogenetic analysis showed that all RSV-A and RSV-B were ON1 and BA9 genotypes, respectively. ON1 genotypes were further divided into two clades. The majority of ON1 strains formed a unique genetic clade with T113I, V131D, N178 G, and H258Q mutations. Furthermore, RSV infection was an independent risk factor for ventilator use (OR = 9.55, 95% CI 1.87-48.64). There was a high incidence of RSV among hospitalized children during winter 2021-2022 in Bengbu with ON1 and BA9 being the dominant strains. This study demonstrated the molecular epidemiological characteristics of RSV in children with respiratory infections in Bengbu, China.

Analysis of deafness susceptibility gene of neonates in northern Guangdong, China

This study aimed to explore the molecular epidemiology characteristics of deafness susceptibility genes in neonates in northern Guangdong and provide a scientific basis for deafness prevention and control. A total of 10,183 neonates were recruited between January 2018 and December 2022 at Yuebei People's Hospital. Among these, a PCR hybridization screening group of 8276 neonates was tested for four deafness genes: GJB2, SLC26A4, mtDNA, and GJB3 by PCR hybridization. Another group used next-generation sequencing (NGS) to detect genetic susceptibility genes in 1907 neonates. In PCR hybridization screening group, 346 (4.18%) of 8276 neonates were found to be carriers of the deafness gene. Among these, 182 (2.2%) had GJB2 variants, 114 (1.38%) had SLC26A4 variants, 35 (0.42%) had mtDNA variants, and 15 (0.18%) had GJB3 variants. In NGS Screening Group, 195 out of 1907 neonates were found to be carriers of the deafness gene, with a positive rate of 10.22%. Among these, 137 (7.18%) had GJB2 variants, 41 (2.15%) had SLC26A4 variants, 11 (0.58%) had mtDNA variants, and 6 (0.31%) had GJB3 variants. The prevalence of deafness gene variants was high in Northern Guangdong Province. The most common gene for deafness was GJB2, followed by SLC26A4 and mtDNA. GJB3 variants are rare. Compared with PCR hybridization method, NGS technology can expand the screening scope and greatly improve the detection rate of deafness genes. The c.109G>A of GJB2 was found to occur at a high frequency, which should be considered. Therefore, it is important to conduct neonatal deafness gene screening to prevent and control hereditary deafness.

Prevalence and genotype/subtype distribution of Enterocytozoon bieneusi and Blastocystis in donkeys in Shanxi Province, north China.

Enterocytozoon bieneusi and Blastocystis may cause diarrhea in humans and various animals. However, little information is available regarding the prevalence and genetic diversity of E. bieneusi and Blastocystis in donkeys. To fill this gap, we molecularly assessed E. bieneusi and Blastocystis in fecal samples from donkeys (n = 815) in Shanxi Province, north China. The overall prevalence of E. bieneusi and Blastocystis in donkeys was 8.1% and 0.2%, respectively. Region and age were risk factors associated with E. bieneusi infection in donkeys. Three internal transcribed spacer (ITS) genotypes of E. bieneusi were identified in the current study, including two previously described genotypes (D and Henan-IV) and one novel genotype (named SXD1). Of which, genotype D was found to be the most prevalent. Phylogenetic analysis demonstrated that the three genotypes belonged to group 1, implying a potential of zoonotic transmission. Multilocus sequence typing showed that 19, 15, 13, and 22 types were identified at the loci MS1, MS3, MS4, and MS7, respectively, forming six multilocus genotypes (MLGs) distributed in the genotype D. One Blastocystis subtype (ST33) was identified, which has previously been reported only in horses. This is the first molecular-based description of E. bieneusi and Blastocystis infections in donkeys in Shanxi Province, north China, contributing to a better understanding of transmission dynamics and molecular epidemiological characteristics of the two intestinal protozoa.