Klebsiella pneumoniae cryptogenic liver abscess and endophthalmitis – a case report and review of literature

Klebsiella pneumoniae has emerged as the predominant pathogenic agent of liver abscess in Asia, and the incidence is increasing worldwide. Hypervirulent strains are associated with septic metastatic dissemination in the eyes, lungs, and central nervous system, causing severe morbidity. We present the case of a 54year old man, with no previous comorbidities, admitted in emergency for the blind red painful eye. Further investigation documented septic endophthalmitis with transscleral extension and orbital cellulitis. Thoraco-abdominal computed tomography evidenced a hepatic abscess as the locus of the primary infection. Intravenous antibiotherapy with cefuroxime, followed by meropenem and vancomycin were efficient for managing the hepatic abscess. However, as the eyeball was perforated at the admission, evisceration was performed. The vitreous sample revealed Klebsiella pneumoniae, with a positive string test as the etiologic agent. The diagnostic and therapeutic management required a permanent collaboration between an ophthalmologist, infectious diseases specialist, surgeon, and radiologist.

Detection of extensively drug-resistant and hypervirulent Klebsiella pneumoniae ST15, ST147, ST377 and ST442 in Iran

In this study, we focused on the emergence of extensively drug-resistant (XDR), pandrug-resistant (PDR), and hypervirulent Klebsiella pneumoniae (hvKP) in Iran. During 2018 to 2020 a total of 52 K. pneumoniae isolates were collected from different clinical specimens. The hvKP isolates were identified by PCR amplification of virulence and capsular serotype-specific genes. Hypermucoviscous K. pneumoniae (hmKP) were identified by string test. Carbapenem-resistant hvKP (CR-hvKP), multidrug-resistant hvKP (MDR-hvKP), extensively drug-resistant hvKP (XDR-hvKP), and pandrug-resistant hvKP (PDR-hvKP) were determined by disc diffusion method, Carba-NP test and PCR method. XDR-hvKP isolates were typed by multilocus sequence typing (MLST). Among all K. pneumoniae isolates 14 (26.9%) were identified as hvKP and 78.6% (11/14) of them were hmKP however, none of the classic K. pneumoniae (cKP) isolates were hmKP. The predominant capsular serotype of hvKP was K2 (42.85%) followed by K1 (35.71%). The prevalence of MDR-hvKP, XDR-hvKP and PDR-hvKP isolates were 6 (42.9%), 5 (35.7%) and 1 (7.1%), respectively. ESBL production was found in 85.7% of hvKP isolates and most of them carried bla TEM gene (78.6%) and 6 isolates (42.9%) were CR-hvKP. Among hvKP isolates, 1 (7.1%), 2 (14.3%), 3 (21.4%), 8 (28.6%), and 11 (78.6%) carried bla NDM-6, bla OXA-48, bla CTX-M, bla SHV, and bla TEM genes, respectively. According to MLST analysis, 2, 1, 1, and 1 XDR-hvKP isolates belonged to ST15, ST377, ST442, and ST147, respectively. The occurrence of such isolates is deeply concerning due to the combination of hypervirulence and extensively drug-resistance or pandrug-resistance.

A New Era: Large Subsea Multiphase Compressor - Driven by Subsea Adjustable Speed Drive

The use of subsea processing equipment, which maintains, increases, and accelerates oil and gas production, is now more and more widespread in offshore subsea field developments. Furthermore, there is a strong drive for electrification of offshore fields, both subsea and topside, to lower emissions. To meet the technical challenges, a significant effort is put into research and technology development by academia and the industry. ABB, a specialist in electrical equipment and control systems, and OneSubsea, a specialist in subsea processing, have executed large development programs organized as Joint Industry Projects (JIPs) together with oil and gas operators. In this paper, we discuss how ABB and OneSubsea joined forces in testing and validating their respective subsea technologies as a full subsea system for subsea multiphase gas compression. This paper presents the world's first full-scale, combined subsea adjustable speed drive (ASD) and multiphase compressor (WGC6000) string test. In spring of 2020, both the ASD, and the WGC6000 reached Technology Readiness Level 4. The string test, with both units concurrently submerged, completed its witness test program in June 2020, with mapping of the WGC6000 speed and power envelope and a subsequent 24 h thermal stability run. The flawless test result confirms the strategic development road map for all the involved partners. The technologies presented in this paper are now fully qualified and available for commercial use enabling a paradigm shift in subsea oil and gas production.

Resistance patterns and clinical outcomes of Klebsiella pneumoniae and invasive Klebsiella variicola in trauma patients

Recent reclassification of the Klebsiella genus to include Klebsiella variicola, and its association with bacteremia and mortality, has raised concerns. We examined Klebsiella spp. infections among battlefield trauma patients, including occurrence of invasive K. variicola disease. Klebsiella isolates collected from 51 wounded military personnel (2009–2014) through the Trauma Infectious Disease Outcomes Study were examined using polymerase chain reaction (PCR) and pulsed-field gel electrophoresis. K. variicola isolates were evaluated for hypermucoviscosity phenotype by the string test. Patients were severely injured, largely from blast injuries, and all received antibiotics prior to Klebsiella isolation. Multidrug-resistant Klebsiella isolates were identified in 23 (45%) patients; however, there were no significant differences when patients with and without multidrug-resistant Klebsiella were compared. A total of 237 isolates initially identified as K. pneumoniae were analyzed, with 141 clinical isolates associated with infections (remaining were colonizing isolates collected through surveillance groin swabs). Using PCR sequencing, 221 (93%) isolates were confirmed as K. pneumoniae, 10 (4%) were K. variicola, and 6 (3%) were K. quasipneumoniae. Five K. variicola isolates were associated with infections. Compared to K. pneumoniae, infecting K. variicola isolates were more likely to be from blood (4/5 versus 24/134, p = 0.04), and less likely to be multidrug-resistant (0/5 versus 99/134, p<0.01). No K. variicola isolates demonstrated the hypermucoviscosity phenotype. Although K. variicola isolates were frequently isolated from bloodstream infections, they were less likely to be multidrug-resistant. Further work is needed to facilitate diagnosis of K. variicola and clarify its clinical significance in larger prospective studies.

A case report of pyogenic liver abscess caused by hypervirulent Klebsiella pneumoniae diagnosed by metagenomic next-generation sequencing

A 56-year-old woman with a history of diabetes mellitus presented with high fever but no abdominal pain. An abdominal computed tomography scan showed a large liver abscess. Hypervirulent, string test-positive, rmpA/ ampA2-, and iutA-positive Klebsiella pneumoniae was rapidly identified from drainage fluid of the liver abscess using metagenomic next-generation sequencing (mNGS). After intravenous antibiotic therapy and drainage of the abscess, the patient’s condition resolved. This case report highlights the value of mNGS in rapidly and accurately identifying a pathogenic microorganism, which helps reduce the incidence of antimicrobial resistance and enables the targeted use of antibiotics.

Virulence among different types of hypervirulent Klebsiella pneumoniae with multi-locus sequence type (MLST)-11, Serotype K1 or K2 strains

Background Two different types of hypervirulent K. pneumoniae (HvKp), the MLST-11 and serotype K1/K2 strains, have been frequently described in recent studies. Although these two types of strains were described to be HvKp, their virulence was not compared. In this study, in vitro and in vivo approaches were used to assess differences in virulence. Materials and methods A total of twenty-nine isolates, including 6 strains of each of serotype K1 and K2 isolates and 17 strains of ST11 isolates, were selected for this study. Phenotypic tests of virulence were performed by the string test and analysis of the virulent associated genes was detected by PCR. In vitro models of serum resistance and phagocytosis were used as the parameters to assess the virulence. In-frame deletion of virulence-associated genes was performed to study their contributions to virulence. The median lethal dose, i.e., the LD50, in mice was determined following IP injection. Results Although serotype K1 and K2 strains and ST11 isolates had similar virulence gene profiles, the ST11 isolates showed less serum and phagocytic resistance than the serotype K1/K2 isolates. The mouse lethality test revealed that all ST11 isolates were unable to cause lethality, even at > 107 CFU, while serotypes K1 and K2 showed an LD50 at ≤ 103 CFU. Aerobactin or capsule knockout mutants exhibited a lower LD50 than the parental strain, while capsule mutants showed a more significant decrease in LD50. Conclusion Since there was a significant difference in virulence levels between the two types of HvKp when assessed in in vitro and in vivo models, it may be better to use the designation "HvKp" for some strains based on animal studies to avoid confusion. Virulence and non-virulence could be analysed in a relative manner, especially in comparison studies.

Virulence Characteristics and Molecular Epidemiology of Pyogenic Liver Abscess Causing Multidrug Resistant Klebsiella pneumoniae in Wenzhou, China

Background To date, little is known about the virulence characteristics of pyogenic liver abscess (PLA) that cause multidrug resistant (MDR) Klebsiella pneumoniae (K. pneumoniae), which might be due to the rarity of these strains. This study aimed to analyze the virulence characteristics and molecular epidemiology of 12 MDR strains obtained from 163 PLA cases in a tertiary teaching hospital from the perspective of clinical characteristics, virulence phenotypes, and genotypes. Methods The MDR strains were obtained from sterile fluid samples collected from patients with PLA. The antimicrobial susceptibility testing was confirmed by the agar dilution method and microdilution broth method. The virulence phenotypes were analyzed by the growth curves, string test, capsular quantification, serum killing test, biofilm formation assay and infection model. Polymerase chain reaction (PCR) was used to investigate the virulence genotypes. The molecular epidemiology was identified by multilocus sequence typing (MLST). Results The results of growth curves, string test, capsular quantification, serum killing test, biofilm formation assay, and infection model revealed that the virulence phenotypes of the 12 PLA-causing MDR K. pneumoniae were similar to or more obvious than those of the typical hypervirulent K. pneumoniae strains. These MDR strains were mainly non-K1/K2 serotypes and carried multiple virulence genes. The results of MLST illustrated that the MDR strains were categorized into 9 sequence types. Conclusions This is the first study to analyze the virulence characteristics in PLA-causing MDR strains. The data revealed the coexistence of hypervirulence and MDR in PLA-causing MDR K. pneumoniae strains, and the clones of these strains were diverse and scattered. Also, one ST11 carbapenem-resistant hypervirulent strain was identified in PLA.

Virulence Characteristics and Molecular Epidemiology of Pyogenic Liver Abscess Causing Multidrug Resistant Klebsiella pneumoniae in Wenzhou, China

Background: To date, little is known about the virulence characteristics of pyogenic liver abscess (PLA) that cause multidrug resistant (MDR) Klebsiella pneumoniae (K. pneumoniae), and this might be due to that these strains are rare. This study aimed to analyze the virulence characteristics and molecular epidemiology of 12 MDR strains obtained from 163 PLA cases in a tertiary teaching hospital from the perspective of clinical characteristics, virulence phenotypes, and genotypes.Results: The results of growth curves, string test, capsular quantification, serum killing test, biofilm formation assay, and infection model revealed that the virulence phenotypes of the 12 PLA-causing MDR K. pneumoniae were similar or even more obvious than those of typical hypervirulent K. pneumoniae strains. These MDR strains were mainly non-K1/K2 serotypes and carried multiple virulence genes. The results of multilocus sequence typing (MLST) illustrated that the MDR strains were categorized into 9 sequence types.Conclusions: This study is the first to analyze the virulence characteristics in PLA-causing MDR strains. Our data exhibited the coexistence of hypervirulence and MDR in PLA-causing MDR K. pneumoniae strains, and the clones of those PLA-causing MDR strains were diverse and scattered. This study first found one ST11 carbapenem-resistant hypervirulent strain in PLA.