Capsular Type Research Articles

Characterisation of Pasteurella multocida Strains from Different Lesions in Rabbits.

Pasteurellosis, a disease caused by Pasteurella multocida, is responsible for economic losses in rabbit industrial farms due to rhinitis, conjunctivitis, pneumonia, metritis, mastitis, orchitis, subcutaneous abscesses, otitis, encephalitis, and septicaemic forms. Although the occurrence of the disease is conditioned by predisposing factors that affect the rabbit immune response, the strains of P. multocida involved in the infection may have a different pathogenic ability. Therefore, typing of strains spread among the rabbits is important to assess their pathogenic potential. The aim of this study is to investigate the P. multocida strains responsible for disease in rabbit industrial farms. A total of 114 strains identified from different lesions were serotyped. Additionally, the presence of virulence-associated genes was investigated using three PCR (polymerase chain reaction) protocols. Capsular type A was prevalently found in strains from respiratory lesions while types D and F in those from metritis, mastitis, and other lesions. Different associations between some virulence-associated genes and both capsular type and lesions found in rabbits were detected. The presence of 8 virulence-associated genes seems to increase the occurrence of metritis. In addition, strains belonging to capsular type A and responsible for respiratory disorders especially, were found equipped with 10 and 11 virulence-associated genes. Nevertheless, the presence of strains responsible only for rhinitis was also detected among the latter, suggesting that the pathogenic ability of the bacteria depends on the expression rather than the presence of a gene.

Molecular genetic determinants of virulence of Streptococcus agalactiae isolated from pregnant women and newborns in St. Petersburg and the Leningrad region in 2010–2023

Introduction. Colonization of the reproductive organs of pregnant women with group B streptococci (GBS; Streptococcus agalactiae) can lead to severe perinatal and neonatal pathology. In modern conditions, aside from the prevention of antenatal infection of the fetus during childbirth using antibacterial drugs, vaccination is also necessary. In this regard, surveillance of GBS genotypes is an important task. Objective. To determine the molecular genetic determinants of virulence of Streptococcus agalactiae isolated from pregnant women and newborns, and to monitor the distribution of capsular polysaccharides types and pili profiles in GBS clinical isolates. Materials and methods. The study used clinical isolates of GBS (n = 420) isolated from pregnant women and newborns in 2010–2023.The bacteriological method was used for isolation of S. agalactiae. PCR method was used to determine the types of capsular polysaccharides, pili, and whether the strains belonged to the hypervirulent sequence type ST-17. Results. During 13 years of observation, the predominance of Ia, III and V genotypes of GBS capsular polysaccharides was noted both in pregnant women and in newborns. The frequency of occurrence of genotype Ib increased from 0.7 to 6.7%, genotype V from 12.1 to 24.4%, and the prevalence of genotype III decreased significantly from 41.1 to 21.1%. Hypervirulent sequence type ST-17 was detected in 6 pregnant women and 2 newborns. However, there were no signs of neonatal infection in these children. More than half of all clinical isolates of S. agalactiae had pili genotypes PI-1 + PI-2a, as well as pili genotypes PI-2a and PI-1 + PI-2b. The distribution of pili types did not change over 13 years of the surveillance period. Conclusion. Surveillance of the GBS capsular polysaccharides and pili genotypes is necessary for the development of effective preventive vaccines.

Macrolide resistance among Streptococcus agalactiae during COVID-19 public health emergency in Brazil.

During COVID-19 public health emergence, azithromycin was excessively used in Brazil, as part of a controversial "early treatment", recommended by former national health authorities. Excessive usage of macrolides may increase resistance rates among beta-hemolytic streptococci. Therefore, this study aimed to investigate the occurrence of resistance to erythromycin and clindamycin among Streptococcus agalactiae recovered from February 2020 to May 2023. Bacterial isolates (n = 116) were obtained from pregnant women and submitted to antimicrobial susceptibility testing, investigation of macrolide resistance phenotypes and genotypes, and identification of capsular type. The overall rate of erythromycin not susceptible (NS) isolates was 25.9%, while resistance to clindamycin was 5.2%. Drug efflux, associated with the M phenotype and mef(A) gene, was the prevalent mechanism of resistance (80%). Capsular type Ia was predominant (39.8%), followed by II, III, and V (17.7% each). A higher diversity of types was observed in the last years of the study. Type IV has had an increasing trend over time, being the fourth most common in 2023. The majority of the isolates that expressed the M phenotype presented capsular type Ia, while those with iMLS phenotype presented capsular type V. Despite no causal relationship can be established, azithromycin excessive usage may be a possible factor associated with this higher rate of erythromycin NS isolates, compared with most previous national studies. On the other hand, resistance to clindamycin has not changed significantly. Therefore, in the studied clinical setting, clindamycin remains a useful alternative to intrapartum prophylaxis among penicillin-allergic pregnant women.

Microbiological and molecular genetic characteristics of Klebsiella pneumoniae isolates, extracted under conditions of cardiac surgery hospital

Klebsiella pneumoniae is one of the main causative agents of healthcare-associated infections (HAI) worldwide. The study was aimed at molecular characterization of beta-lactam antibiotic resistance in K. pneumoniae isolated in the cardiac surgery hospital, identify hypervirulent isolates and assess isolate genetic relatedness. K. pneumoniae isolated from the clinical material of patients (n = 50) at cardiac surgery departments as well as anesthesiology and reanimation department treated at the cardiovascular surgery hospital in Perm from July 2021 to December 2022 were analyzed. Bacteriological studies were performed on an automatic analyzer WalkAway-96Plus (Beckman Coulter, USA). The sensitivity to thirteen antimicrobials, production of extended-spectrum beta-lactamases (ESBL) and multidrug resistance (MDR) phenotype were assessed. The string test was used to screen hypermucoviscous K. pneumoniae. Isolate relatedness (ERIC-PCR), presence of beta-lactamase genes (blaTEM, blaCTX-M, blaSHV, blaOXA, blaKPC, blaVIM-2, blaIMP-1, blaNDM-1), as well as genes associated with hypervirulence (prmpA, iucA, peg-344, wzyK2, magA) were analyzed by PCR. Amplifications were performed in a DNA Engine Dyad Thermal Cycler (Bio-Rad, USA). Gel documentation system Gel-Doc XR (Bio-Rad, USA) was used for band visualization and data documentation. According to the study results, it was found that carbapenem-resistant isolates accounted for almost 76% of all isolates, the ESBL-phenotype had 90%, and MDR-phenotype — 88% of studied isolates. According to the string test results, 8% of K. pneumoniae isolates had a hypermucoviscous phenotype. As for genes associated with hypervirulence, it was shown that the iucA gene was the most common, amplified in 54% of isolates, prmpA was detected in 38% of isolates, 48% of isolates had wzyK2 or magA genes encoding capsular type K1/K2. Almost a third of K. pneumoniae samples contained a combination of the rmpA and iucA genes, and they were isolated more often in the group of patients with active infection. Only carbapenem-sensitive microorganisms had hypermucoviscous phenotype, K1 capsular type, and a combination of prmpA, iucA, peg-344 genes, whereas the K2 capsular type was most common among carbapenem-resistant K. pneumoniae. Based on molecular genetic typing, it was found that 24% of K. pneumoniae isolates were assigned to four genome groups of identical cultures, 76% of the isolates had individual profiles. Closely related isolates were found among patients from different departments that indicates a potential pathogen circulation in the closed circuit “surgery department–department of anesthesiology” and “reanimation–surgery department”.

Exploring the resistome, virulome, and mobilome of multidrug-resistant Klebsiella pneumoniae isolates: deciphering the molecular basis of carbapenem resistance

BackgroundKlebsiella pneumoniae, a notorious pathogen for causing nosocomial infections has become a major cause of neonatal septicemia, leading to high morbidity and mortality worldwide. This opportunistic bacterium has become highly resistant to antibiotics due to the widespread acquisition of genes encoding a variety of enzymes such as extended-spectrum beta-lactamases (ESBLs) and carbapenemases. We collected Klebsiella pneumoniae isolates from a local tertiary care hospital from February 2019–February 2021. To gain molecular insight into the resistome, virulome, and genetic environment of significant genes of multidrug-resistant K. pneumoniae isolates, we performed the short-read whole-genome sequencing of 10 K. pneumoniae isolates recovered from adult patients, neonates, and hospital tap water samples.ResultsThe draft genomes of the isolates varied in size, ranging from 5.48 to 5.96 Mbp suggesting the genome plasticity of this pathogen. Various genes conferring resistance to different classes of antibiotics e.g., aminoglycosides, quinolones, sulfonamides, tetracycline, and trimethoprim were identified in all sequenced isolates. The highest resistance was observed towards carbapenems, which has been putatively linked to the presence of both class B and class D carbapenemases, blaNDM, and blaOXA, respectively. Moreover, the biocide resistance gene qacEdelta1 was found in 6/10 of the sequenced strains. The sequenced isolates exhibited a broad range of sequence types and capsular types. The significant antibiotic resistance genes (ARGs) were bracketed by a variety of mobile genetic elements (MGEs). Various spontaneous mutations in genes other than the acquired antibiotic-resistance genes were observed, which play an indirect role in making these bugs resistant to antibiotics. Loss or deficiency of outer membrane porins, combined with ESBL production, played a significant role in carbapenem resistance in our sequenced isolates. Phylogenetic analysis revealed that the study isolates exhibited evolutionary relationships with strains from China, India, and the USA suggesting a shared evolutionary history and potential dissemination of similar genes amongst the isolates of different origins.ConclusionsThis study provides valuable insight into the presence of multiple mechanisms of carbapenem resistance in K. pneumoniae strains including the acquisition of multiple antibiotic-resistance genes through mobile genetic elements. Identification of rich mobilome yielded insightful information regarding the crucial role of insertion sequences, transposons, and integrons in shaping the genome of bacteria for the transmission of various resistance-associated genes. Multi-drug resistant isolates that had the fewest resistance genes exhibited a significant number of mutations. K. pneumoniae isolate from water source displayed comparable antibiotic resistance determinants to clinical isolates and the highest number of virulence-associated genes suggesting the possible interplay of ARGs amongst bacteria from different sources.

Three-Part Fracture Dislocation and Four-Part Fracture Dislocation of the Proximal Humerus: How Different are the Glenoid Labrum and Capsular Injuries Between Them?

Anterior fracture dislocation of the shoulder may have associated injury to the glenoid labrum and/or capsule. There is a need to look at the possible patterns of capsulo-labral injuries intra-operatively and correlate them with pre-operative radiographs and CT scans. It can enable surgeons to predict the patterns of soft-tissue injuries in a specific fracture type. Patients operated for ORIF of 3- and 4-part anterior fracture dislocation between January 2017 and December 2022 were included in the study. The following data were collected: demographic details, fracture morphology and classification on radiograph and CT scan, neurovascular injury, the subtype of anterior dislocation, and intra-operative identifiable injury to glenoid labrum and/or capsule. A total of 24 cases (mean age 40 ± 10years) of anterior fracture dislocation of the shoulder were included in the study and were grouped based on Neer's classification. 12 patients had 3-part anterior fracture dislocation (3-part Group) with a mean age of 34 ± 9years, while 12 patients had 4-part anterior fracture dislocation (4-part Group) with a mean age of 46 ± 7years (p = 0.001). 10 out of 12 patients in the 3-part Group had the subcoracoid position of the dislocated head, whereas the head was present in 9 out of 12 patients of the 4-part Group at the preglenoid position (p = 0.003). The head position was at a mean distance of 1.85cm from the anterior glenoid rim in the 4-part Group, whereas the head was engaged at the anterior rim of the glenoid in the 3-part Group. The medial metaphyseal beak was present in 11 out of 12 patients in the 3-part Group, whereas it was absent in all the cases of the 4-part Group (p = 0.001). 92% of the included patients in our study had capsulo-labral injury. 11 out of 12 patients in the 3-part Group had labral injury compared to 10 out of 12 patients in the 4-part Group with severe capsular stripping (p = 0.001). The 3-part fracture dislocation with radiological findings such as the long medial metaphyseal beak and subcoracoid position of the dislocated head had a strong association with a glenoid labral injury, whereas the 4-part fracture dislocation type had a widely displaced preglenoid position of the dislocated head with an absent metaphyseal beak and had a strong association with a capsular type of soft-tissue injury. III.

Analysis of virulence profiles in clinical isolates of Klebsiella pneumoniae from renal abscesses: clinical significance of hypervirulent isolates.

Klebsiella pneumoniae can cause a wide range of infections. Hypervirulent K. pneumoniae (hvKp), particularly associated with the K1 and K2 capsular types, is an increasingly significant microorganism with the potential to cause invasive infections, including renal abscesses. Despite the rising prevalence of hvKp infections, information on renal abscesses caused by K. pneumoniae is limited, and the clinical significance of hvKp associated with specific virulence genes remains elusive. This study performed at a 1200-bed tertiary hospital sought to identify the clinical and microbiological characteristics of renal abscesses caused by K. pneumoniae, focusing on various virulence genes, including capsular serotypes and multilocus sequence typing (MLST). Over an 8-year period, 64 patients with suspected renal abscesses were reviewed. Ten patients diagnosed with K. pneumoniae-related renal abscesses were ultimately enrolled in the study. Among the isolates from the 10 patients, capsular serotype K2 was predominant (40.0%), followed by K1 (30.0%). The most common sequence type by MLST was 23 (40.0%). In particular, six patients (60.0%) harbored specific genes indicative of hvKp: iucA, peg-344, rmpA, and rmpA2. Our findings highlight the importance of hvKp as a pathogen in renal abscesses. Although the nature of hvKp is relatively unknown, it is widely recognized as a highly virulent pathogen that can infect relatively healthy individuals of various ages and simultaneously cause infections at multiple anatomical sites. Therefore, when treating patients with K. pneumoniae-related renal abscesses, caution is necessary when considering the characteristics of hvKp, such as potential bacteremia, multi-organ abscess formation, and metastatic spread.

KPC-2 and VIM-1 producing Klebsiella pneumoniae ST39 high-risk clone isolated from aclinical sample in Volos, Greece.

Klebsiella pneumoniae is a major human pathogen, because it causes both community- and hospital-acquired infections. Several multidrug-resistant high-risk clones of K. pneumoniae have been reported worldwide, and these are responsible for high numbers of difficult-to-treat infections. In Greece, a K.pneumoniae ST39 high-risk clone was detected in 2019 in a survey of carbapenem- and/or colistin-resistant Enterobacteriacae. The present study included nine carbapenem-resistant K. pneumoniae (CRKP) isolates collected during a retrospective analysis from October 2020 to December 2020. They were isolated from nine different patients hospitalized in the intensive care unit (ICU) of a hospital in Volos, Greece, and they were selected for analysis due to their phenotypic profile. In this study, we analyzed A165 strain K. pneumoniae ST39 isolated from a blood culture in November 2020. Whole-genome sequencing (WGS) was performed using Ion Torrent Platform, and resistance genes, virulence determinants, capsular types, insertion sequences, phage regions, and clustered regularly interspaced palindromic repeats (CRISPR) regions were detected by bioinformatic analysis. The molecular characterizationrevealed antimicrobial resistance genes, including sul2 for sulfamethoxazole; dfrA1 fortrimethoprim; blaVIM-1 and blaKPC-2 for carbapenems; aac(6')-II for aminoglycosides; fosA forfosfomycin and aad1 for streptomycin, blaSHV-40, blaSHV-85, blaSHV-79, blaSHV-56, and blaSHV-89 forbeta-lactams. Point mutations were identified in ompK36, and ompK37 and in acrR, gyrA, parC. Several replicons were found, including CoIRNA, IncC, IncFIB(K), IncFIB(pQiL), and IncFII(K). Thecapsular typing revealed that the strain was KL23, O2afg. The genome sequence of A165 was submitted to NCBI under PRJNA1074377 and have been assigned to Genbank accession number JAZIBV000000000.

Molecular characterization of Pasteurella multocida from cats and antibiotic sensitivity of the isolates.

Companion animals, including dogs and cats, are frequently identified as sources of Pasteurella multocida, a bacterium that can be transmitted to humans and cause infections. This survey defines the prevalence, antibiotic sensitivity, capsular types, lipopolysaccharide (LPS) types and virulence factors of P. multocida isolated from cats. A total of 100 specimens from various cat breeds were collected. P. multocida was characterized using both biochemical tests and PCR. Genotypes of isolates were determined using capsular and LPS typing methods. Additionally, virulotyping was performed by detecting the presence of 12 virulence-associated genes. Disk diffusion was used to determine the antibiotic sensitivity of the isolates. The prevalence of P. multocida in cats was 29%. Among the isolates, the majority were capsular type A (96.5%) and type D (3.4%), with a predominant presence of type A. Twenty-six of the isolates (89.66%) belonged to LPS genotype L6, whereas three isolates (10.3%) belonged to genotype L3. Among the 12 virulence genes examined, sodC, oma87, ptfA, nanB and ompH showed remarkable prevalence (100%). The toxA gene was detected in four isolates (13.8%). Variations were observed in other virulence genes. The nanH gene was present in 93.1% of the isolates, whereas the pfhA gene was detected in 58.6% of the isolates. The exbD-tonB, hgbB, sodA and hgbA genes showed prevalence rates of 96.5%, 96.5%, 96.5% and 82.8%, respectively. Additionally, particular capsule and LPS types were associated with specific virulence genes. Specifically, the toxA and pfhA genes were found to be more prevalent in isolates with capsular type A and LPS genotype L6. Most isolates were resistant to ampicillin, clindamycin, lincomycin, streptomycin and penicillin. According to this epidemiological and molecular data, P. multocida from cats possess several virulence-associated genes and are resistant to antimicrobial medicines commonly used in humans and animals. Thus, it is crucial to consider the public health concerns of P. multocida in humans.

Epidemiology and molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolated from neonatal intensive care units in General Hospital of Ningxia Medical University, China, 2017-2021.

This study aimed to retrospectively investigate the epidemiology and molecular characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates from neonatal intensive care units (NICU) between 2017 and 2021. The antibacterial susceptibility of all strains was assessed using the VITEK 2 compact system. The presence of antibiotic resistance, virulence genes, sequence types (STs), capsular (K) types, and the wzi genes was determined through polymerase chain reaction (PCR). Molecular typing was performed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI. Additionally, the virulence potential of peg344-positive strains was evaluated using the string test and mouse intraperitoneal infection models. Whole-genome sequencing was conducted on the DNB system and PacBio platforms. A total of 46 CRKP isolates were collected during the study period. Out of these, 93.47% (43/46) were identified as CRKP strains belonging to the ST76-K10 type carrying blaNDM-5. It was observed that CRKP infection resulted in more severe clinical symptoms compared to CRKP colonization. Among the CRKP strains, a hypervirulent CRKP strain called KP-63, belonging to the ST23 type, was identified. This strain exhibited high mortality in the mouse infection model and was found to possess virulence genes. Genomic alignment analysis revealed a significant similarity between the virulence plasmid from KP-63 strain (pKP-63) and pK2044 from the hypervirulent K. pneumoniae strain NTUH-2044. There has been a potential dissemination of ST76-K10 type CRKP carrying blaNDM-5 in the NICU at Ningxia Hospital. Neonatal CRKP infection has been found to cause more severe clinical symptoms than colonization. Furthermore, we have discovered a CR-hvKP strain of ST23 with serotype K1, which exhibits a significant resemblance in its virulent plasmid to pK2044. Therefore, it is crucial to enforce effective measures to restrict the spread and hinder the evolution of CRKP within the hospital.

Phenotypic and molecular characterization of multi-drug resistant Klebsiella spp. isolates recovered from clinical settings

Klebsiella pneumoniae is a Gram-negative bacterium that colonizes the gastrointestinal tract and nasopharynx with many being linked to nosocomial infections. Extended-spectrum β-lactamases (ESBL)-producing and carbapenem-resistant K. pneumoniae is recognized by the World Health Organization (WHO) as a critical public health concern. In this study, whole-genome sequencing (WGS) – based analysis was performed to understand the molecular epidemiology of multi-drug resistant Klebsiella spp. clinical isolates. Genome comparison, multi-locus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and whole-genome-SNP-based phylogenetic analysis (wg-SNP) were used for in-depth molecular characterization. in silico typing was used to determine the resistance genes, virulence factors, Inc. groups, and capsular types. All except one isolate were non-susceptible to meropenem and 89% were non-susceptible to ertapenem and imipenem. blaNDM, blaOXA-48, and blaKPC were the detected carbapenemases with blaNDM-1 found in half of the sequenced genomes. Resistance to colistin was detected in one isolate and was linked to several genetic alterations in crrB, pmrB, and pmrC genes. The most common plasmid type was IncFIB followed by IncR, and the Type 3 fimbriae, encoded by the mrkABCDF operon, was conserved among all isolates. The most common sequence- (ST) and K-type detected were ST147 and K64. The prevelance and the genomic relatedness of ST147 isolates, as shown by the data from SNP-based phylogenetic analysis, PFGE, and genomic clustering, may be an outbreak marker. However, this can only be validated through a more comprehensive study encompassing a wider sampling scheme and over an extended timeframe.

Carbapenem-resistant hypervirulent ST23 Klebsiella pneumoniae with a highly transmissible dual-carbapenemase plasmid in Chile

BackgroundThe convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K. pneumoniae (hvKp) strains, frequently from sequence type 23 (ST23) and having a K1 capsule, have been associated with severe community-acquired invasive infections. Although hvKp were initially restricted to Southeast Asia and primarily antibiotic-sensitive, carbapenem-resistant hvKp infections are reported worldwide. Here, within the carbapenemase production Enterobacterales surveillance system headed by the Chilean Public Health Institute, we describe the isolation in Chile of a high-risk ST23 dual-carbapenemase-producing hvKp strain, which carbapenemase genes are encoded in a single conjugative plasmid.ResultsPhenotypic and molecular tests of this strain revealed an extensive resistance to at least 15 antibiotic classes and the production of KPC-2 and VIM-1 carbapenemases. Unexpectedly, this isolate lacked hypermucoviscosity, challenging this commonly used hvKp identification criteria. Complete genome sequencing and analysis confirmed the K1 capsular type, the KpVP-1 virulence plasmid, and the GIE492 and ICEKp10 genomic islands carrying virulence factors strongly associated with hvKp. Although this isolate belonged to the globally disseminated hvKp clonal group CG23-I, it is unique, as it formed a clade apart from a previously reported Chilean ST23 hvKp isolate and acquired an IncN KPC-2 plasmid highly disseminated in South America (absent in other hvKp genomes), but now including a class-I integron carrying blaVIM−1 and other resistance genes. Notably, this isolate was able to conjugate the double carbapenemase plasmid to an E. coli recipient, conferring resistance to 1st -5th generation cephalosporins (including combinations with beta-lactamase inhibitors), penicillins, monobactams, and carbapenems.ConclusionsWe reported the isolation in Chile of high-risk carbapenem-resistant hvKp carrying a highly transmissible conjugative plasmid encoding KPC-2 and VIM-1 carbapenemases, conferring resistance to most beta-lactams. Furthermore, the lack of hypermucoviscosity argues against this trait as a reliable hvKp marker. These findings highlight the rapid evolution towards multi-drug resistance of hvKp in Chile and globally, as well as the importance of conjugative plasmids and other mobile genetic elements in this convergence. In this regard, genomic approaches provide valuable support to monitor and obtain essential information on these priority pathogens and mobile elements.

A novel depolymerase specifically degrades the K62-type capsular polysaccharide of Klebsiella pneumoniae

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is emerging as an imminent threat to worldwide public health because of its high level of antimicrobial resistance, which can result in severe and challenging-to-treat infections. The capsular polysaccharide (CPS) of bacteria is well acknowledged as a crucial virulence factor that shields K. pneumoniae from the host’s innate immune system. Polysaccharide depolymerase, encoded by bacteriophages, can hydrolyze the CPS of K. pneumoniae and may be a promising approach for treating K. pneumoniae infections. In this study, we identified a novel K62-type capsule depolymerase (K62-Dpo30) from the K. pneumoniae phage SH-KP2492. We demonstrated that the K62-Dpo30 depolymerase could specifically degrade the CPS of K62-type K. pneumoniae strains and promote the susceptibility of K62-type K. pneumoniae strains to serum and neutrophil killing. Furthermore, our findings highlight the potential of the K62-Dpo30 depolymerase as a reliable K. pneumoniae capsular typing tool.

Great Plasticity in a Great Pathogen: Capsular Types, Virulence Factors and Biofilm Formation in ESBL-Producing Klebsiella pneumoniae from Pediatric Infections in Uruguay.

Klebsiella pneumoniae is widely recognized as an opportunistic hospital and community pathogen. It is one of the priority microorganisms included in the ESKAPE group, and its antibiotic resistance related to extended-spectrum β-lactamases (ESBL) is a global public health concern. The multi-drug resistance (MDR) phenotype, in combination with pathogenicity factors, could enhance the ability of this pathogen to cause clinical infections. The aim of this study was to characterize pathogenicity factors and biofilm formation in ESBL-producing K. pneumoniae from pediatric clinical infections. Capsular types, virulence factors, and sequence types were characterized by PCR. Biofilm formation was determined by a semiquantitative microtiter technique. MDR phenotype and statistical analysis were performed. The K24 capsular type (27%), virulence factors related to iron uptake fyuA (35%) and kfuBC (27%), and sequence types ST14 (18%) and ST45 (18%) were the most frequently detected. Most of the strains were biofilm producers: weak (22%), moderate (22%), or strong (12%). In 62% of the strains, an MDR phenotype was detected. Strains with K24 capsular type showed an association with ST45 and the presence of fyuA; strains with kfuBC showed an association with moderate or strong biofilm production and belonging to ST14. Weak or no biofilm producers were associated with the absence of kfuBC. The MDR phenotype was associated with the main ESBL gene, blaCTX-M-15. The high plasticity of K. pneumoniae to acquire an MDR phenotype, in combination with the factors exposed in this report, could make it even more difficult to achieve a good clinical outcome with the available therapeutics.

New Obolenskvirus Phages Brutus and Scipio: Biology, Evolution, and Phage-Host Interaction.

Two novel virulent phages of the genus Obolenskvirus infecting Acinetobacter baumannii, a significant nosocomial pathogen, have been isolated and studied. Phages Brutus and Scipio were able to infect A. baumannii strains belonging to the K116 and K82 capsular types, respectively. The biological properties and genomic organization of the phages were characterized. Comparative genomic, phylogenetic, and pangenomic analyses were performed to investigate the relationship of Brutus and Scipio to other bacterial viruses and to trace the possible origin and evolutionary history of these phages and other representatives of the genus Obolenskvirus. The investigation of enzymatic activity of the tailspike depolymerase encoded in the genome of phage Scipio, the first reported virus infecting A. baumannii of the K82 capsular type, was performed. The study of new representatives of the genus Obolenskvirus and mechanisms of action of depolymerases encoded in their genomes expands knowledge about the diversity of viruses within this taxonomic group and strategies of Obolenskvirus-host bacteria interaction.

Capsular specific typing of multidrug-resistant Klebsiella pneumoniae isolated from clinical cases in Ramadi city of Iraq

Capsular specific typing of multidrug-resistant Klebsiella pneumoniae isolated from clinical cases in Ramadi city of Iraq

Capsular gene distribution and RAPD typing of Streptococcus agalactiae isolated from pregnant women

Streptococcus agalactiae has different virulence factors, from which the capsule has the most significant role in the pathogenesis of this organism. We aimed to investigate the distribution of more prevalent capsular genes among different Random Amplified Polymorphic DNA (RAPD) types of S. agalactiae isolated from pregnant women. A total of 106 isolates were collected from 420 vaginal and rectal swabs obtained from pregnant women. The specimens were transferred using Todd Hewitt Broth and were cultured on a blood agar containing antibiotics. The S. agalactiae isolates were identified by the standard microbiological and biochemical tests. The genomic DNAs of S. agalactiae isolates were extracted using an extraction kit. Then, the PCR method was used to detection of the capsular genes. Moreover, The RAPD PCR was used to genotyping of the isolates. The colonization rate of the pregnant women was 25.23%, and there was a statistically significant correlation between the weeks of gestation and the probability of colonization (p-value < 0.05). Also, 31 (29.24%) and 18 (16.98%) pregnant women had a history of abortion and membrane rupture, respectively. In addition, 20 (18.86%), 32 (30.18%), 4 (3.77%), and 6 (5.66%) isolates carried genes encoding capsular types Ia, Ib, III, and V, respectively. None isolates had the type II capsular gene, and other 44 isolates were non-typeable. Nine clones (clusters) of S. agalactiae were observed in the present study with 70% similarity, and 53 different types were identified among the isolates. Except for capsular types III and V that belonged to clones 3, 5, 7, and 9, other capsular types were detected in different RAPD types. We found that the capsular types Ib and Ia were predominant among pregnant women in this area, indicating their significance for vaccine designation. Also, our isolates showed a lower genotypic diversity in RAPD typing. This may be due to the same sources of most isolates.

Genomic Epidemiology Dataset for the Important Nosocomial Pathogenic Bacterium Acinetobacter baumannii

The infections caused by various bacterial pathogens both in clinical and community settings represent a significant threat to public healthcare worldwide. The growing resistance to antimicrobial drugs acquired by bacterial species causing healthcare-associated infections has already become a life-threatening danger noticed by the World Health Organization. Several groups or lineages of bacterial isolates, usually called ‘the clones of high risk’, often drive the spread of resistance within particular species. Thus, it is vitally important to reveal and track the spread of such clones and the mechanisms by which they acquire antibiotic resistance and enhance their survival skills. Currently, the analysis of whole-genome sequences for bacterial isolates of interest is increasingly used for these purposes, including epidemiological surveillance and the development of spread prevention measures. However, the availability and uniformity of the data derived from genomic sequences often represent a bottleneck for such investigations. With this dataset, we present the results of a genomic epidemiology analysis of 17,546 genomes of a dangerous bacterial pathogen, Acinetobacter baumannii. Important typing information, including multilocus sequence typing (MLST)-based sequence types (STs), intrinsic blaOXA-51-like gene variants, capsular (KL) and oligosaccharide (OCL) types, CRISPR-Cas systems, and cgMLST profiles are presented, as well as the assignment of particular isolates to nine known international clones of high risk. The presence of antimicrobial resistance genes within the genomes is also reported. These data will be useful for researchers in the field of A. baumannii genomic epidemiology, resistance analysis, and prevention measure development.

Characterisation of highly virulent and colistin-resistant ST367-KL1 Klebsiella quasipneumoniae subsp. similipneumoniae Strain

ObjectivesTo elucidate the characteristics of a colistin-resistant and hypervirulent Klebsiella quasipneumoniae subsp. similipneumoniae strain (KP8) using whole genome sequencing and various phenotypic assays. MethodsAntimicrobial susceptibility testing was performed using broth microdilution. Whole genome sequencing and comparative genomics were utilised to elucidate genomic characteristics. Phenotypic assays to evaluate virulence factors included measurements of mucosal viscosity, biofilm production, siderophore production, infection of A549 cells, serum-killing assays, and Galleria mellonella infection models. ResultsWhole-genome sequencing revealed that the strain (KP8) belongs to sequence type 367 (ST367) and capsular type 1 (KL1), and it harbours several virulence genes, including regulator of mucoid phenotype (rmpA/A2), salmochelin (iroBCDN) and aerobactin (iucABCDiutA). Antibiotic susceptibility tests showed that KP8 was resistant to colistin. Genome analysis showed that the colistin resistance of KP8 might be related to amino acid insertions in pmrB (L215_D217, insL) and pagP (M1_S3, insV). Importantly, KP8 demonstrated comparable mucosal viscosity, biofilm production capacity, siderophore production levels to hvKP. Serum-killing experiments, A549 cell infection models, and G. mellonella infection models further indicated that KP8 displayed high virulence, akin to the hypervirulent strain NUTH-K2044. Notably, global genome analysis of the K. quasipneumoniae subsp. similipneumoniae strains highlighted that the ST367 lineage has a higher tendency to carry virulence-associated genes compared to other sequence types. The prevalence of virulence-associated factors concentrated within Chinese ST367 isolates reinforces this observation. ConclusionThese findings further enhance our understanding of the resistance and pathogenicity of ST367 K. quasipneumoniae subsp. similipneumoniae strain and also providing a broader perspective on the global epidemiological landscape.

No difference in prevalence of postoperative iliopsoas tendinitis in patients undergoing arthroscopic hip surgery when using absorbable versus non-absorbable suture for capsular closure.

The volume of arthroscopic hip surgery has increased dramatically in recent years with iliopsoas tendinitis (IPT) being one of the most common complications of this procedure. The purpose of this study is to investigate the prevalence of post-operative IPT in patients who undergo arthroscopic hip surgery with capsular closure using absorbable versus non-absorbable suture. This is a single center, single surgeon, retrospective analysis performed between August 2007 and May 2023 comparing two cohorts who underwent hip arthroscopy. Patients were divided into those who underwent surgery with capsular closure using absorbable (Vicryl®, Johnson and Johnson, New Brunswick, NJ) suture and those who underwent capsular closure with non-absorbable suture (Suturetape, Arthrex, Naples FL). All patients who underwent primary or revision hip arthroscopy and were at least 2 months post-operation were initially included in the study. Between August 2007 and May 2023 a total of 1513 hip arthroscopy surgeries were performed. Within this cohort, 1421 hips underwent hip arthroscopy with non-absorbable suture and 64 hips underwent surgery with absorbable suture. There was no significant difference between the proportion of IPT in the non-absorbable cohort (2.3%) versus the absorbable cohort (1.6%) (P = 0.669). Capsular closure with Absorbable sutures was non-inferior to capsular closure with non-absorbable sutures with respect to the proportion of post-operative IPT following hip arthroscopy for FAI. Additionally, the proportion of post-operative IPT was found to be significantly higher in patients undergoing revision versus primary hip arthroscopy, regardless of capsular closure suture type. IV.