Somatic serogroups, capsular types, and species of fecal Klebsiella in patients with ankylosing spondylitis

Association between Klebsiella pneumoniae and ankylosing spondylitis: A systematic review and meta-analysis

AIM

The aim of this study is to evaluate the association between Klebsiella pneumoniae infection and ankylosing spondylitis (AS).

METHOD

Five electronic databases, PubMed, Embase, Medline, Web of Science, and Scopes, were searched until September 29, 2021. Cohort and case-control studies that assessed the association between K. pneumoniae infection and AS were included. Pooled odds ratio (OR) was selected to show the effect size. Subgroup analysis (active or inactive AS) and 2 forms of sensitivity analysis were conducted. All statistical analyses were conducted by using STATA 12.0.

RESULTS

There were 25 case-control studies finally included, including 8 studies concerning presence of K. pneumoniae in feces, and 17 studies concerning serum antibody (immunoglobulin [Ig]G, IgM, IgA) against K. pneumoniae. The results suggested that when compared with healthy people, presence of K. pneumoniae in feces was associated with AS (OR: 5.65; 95% CI: 1.68-19.00). Similarly, when compared with healthy people, higher positive rates of IgA (OR: 6.28; 95% CI: 3.32-11.91) and IgG (OR: 5.22; 95% CI: 1.36-19.99) were observed. Subgroup analyses suggested that association between K. pneumoniae and AS appears stronger in active AS.

CONCLUSION

When compared with healthy people, a significantly higher positive rate of K. pneumoniae in feces, serum IgA and IgG were observed in patients with AS, suggesting that K. pneumoniae probably plays a crucial role in the occurrence of AS. The findings in this study need further prospective investigations for confirmation.

wzi Gene sequencing, a rapid method for determination of capsular type for Klebsiella strains

Pathogens of the genus Klebsiella have been classified into distinct capsular (K) types for nearly a century. K typing of Klebsiella species still has important applications in epidemiology and clinical microbiology, but the serological method has strong practical limitations. Our objective was to evaluate the sequencing of wzi, a gene conserved in all capsular types of Klebsiella pneumoniae that codes for an outer membrane protein involved in capsule attachment to the cell surface, as a simple and rapid method for the prediction of K type. The sequencing of a 447-nucleotide region of wzi distinguished the K-type reference strains with only nine exceptions. A reference wzi sequence database was created by the inclusion of multiple strains representing K types associated with high virulence and multidrug resistance. A collection of 119 prospective clinical isolates of K. pneumoniae were then analyzed in parallel by wzi sequencing and classical K typing. Whereas K typing achieved typeability for 81% and discrimination for 94.4% of the isolates, these figures were 98.1% and 98.3%, respectively, for wzi sequencing. The prediction of K type once the wzi allele was known was 94%. wzi sequencing is a rapid and simple method for the determination of the K types of most K. pneumoniae clinical isolates.

Surgical orodental implications in ankylosing spondylitis

Temporomandibular joint and the pelvic complex are bidirectionally related. Ankylosing spondylitis (AS) is a seronegative arthropathy with the key feature of bony fusion of lumbar vertebrae. A 39 year old known case of AS was presented to private office for left lower impacted third molar surgical removal. Previously, he was rejected to receive oral care for pulpectomy and extraction due to limited mouth opening. Prior to the surgery, lateral neck radiography was obtained to exclude any subluxation of fracture of cervical vertebrae. Neck was supported to insure neck stability during surgical forces. In addition, considering consumption of immunosuppressive medications including corticosteroids, procedure was performed with a great care, with attention to higher possibility of infection and fracture. Access to the surgical site was not desirable, though surgery accomplished without any significant event and the patient discharged with routine analgesic and antibiotics recommendation. Sometimes, impaired access to the oral cavity in patients with AS leads to receive suboptimal or minimal orodental care. Long list of dental implications in these patients may be simplified by considering of careful neck and jaw support, applying at least possible forces and great attention to the infection control rules. It is wised to be performed under patient and skilled hands.

Variants of the Klebsiella pneumoniae OKP chromosomal beta-lactamase are divided into two main groups, OKP-A and OKP-B

Two bla(OKP) subgroups were found, diverging by 4.2%. Subgroups bla(OKP-A) (10 enzyme variants, pIs from 7.1 to 8.3) and bla(OKP-B) (11 variants, pI 7.1) showed similar antibiotic susceptibilities. Sequencing of rpoB, gyrA, and mdh demonstrated a concordant subdivision of Klebsiella pneumoniae phylogenetic group KpII into two subgroups, KpII-A and KpII-B.

Bacteriophages in autoimmune disease and other inflammatory conditions

There are several autoimmune diseases and other inflammatory conditions where an infectious aetiology is suggested by the epidemiology, clinical course and pathological findings. Many candidate bacteria and viruses have been considered as potential aetiological agents but mostly without firm proof. Bacteriophages are viruses that infect bacteria and may be found wherever bacteria are located, but would not be detected unless specifically sought. They have not previously been considered to be pathogens. Bacteriophages are immunogenic and therefore could play a role in the pathogenesis of autoimmune and other inflammatory diseases by acting as antigens on epithelial surfaces, bound to antibody as immune complexes, through molecular mimicry or possibly as superantigens.

Increased serum resistance in Klebsiella pneumoniae strains producing extended-spectrum beta-lactamases

The aim of this study was to determine whether there is an association between serum resistance, O serotypes, and the production of extended-spectrum beta-lactamases (ESBLs) in Klebsiella pneumoniae. Ninety ESBL-producing and 178 non-ESBL-producing K. pneumoniae isolates gathered in five European countries were O serotyped and tested for sensitivity to the serum's bactericidal effect. The frequency of serum-resistant isolates was higher among ESBL-producing strains (30%; 27/90 isolates) than among non-ESBL-producing strains (17.9%; 32/178 isolates) (P = 0.037; odds ratio [OR] = 1.96; 95% confidence interval [95% CI] = 1.08 to 3.53). Although O1 was the most common O serotype in both Klebsiella groups, its frequency among ESBL-producing strains was significantly higher (59%; 53/90 isolates) than among non-ESBL producers (36%; 64/178 isolates) (P = 0.0006; OR = 2.5; 95% CI = 1.52 to 4.29). Furthermore, the prevalence of the O1 serotype was higher among serum-resistant strains of both ESBL-producing (74%; 20/27isolates) and non-ESBL producers (75%; 24/32 isolates) than among serum-sensitive ESBL producers (52.4%; 33/63 isolates) and non-ESBL producers (27.4%; 40/146 isolates). Serum resistance among ESBL-producing strains (36%; 17/47 isolates) versus non-ESBL-producing strains (16%; 27/166 isolates) was also significantly higher after the exclusion of clonal strains (P = 0.0056; OR = 2.9; 95% CI = 1.41 to 6.01). Sixteen ESBL types were detected, among which the frequency of serum resistance was significantly lower among the SHV-producing strains (9/48 isolates) than among the TEM producers (16/35 isolates) (P = 0.016; OR = 3.65; CI = 1.3 to 9.7). Curing ESBL-coding plasmids did not influence the serum resistance of the bacteria; all six plasmid-cured derivatives maintained serum resistance. The present findings suggest that ESBL-producing strains have a greater pathogenic potential than non-ESBL-producing strains, but the linkage between O serotypes, serum resistance, and ESBL production remains unclear at this stage.

Cancer incidence among patients with ankylosing spondylitis in Sweden 1965-95: a population based cohort study

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory joint disease which may lead to extra-articular complications. The disease associated cancer risk has been poorly explored. Recently, tumour necrosis factor alpha blockers have been found to be efficacious in AS, but their long term risk is unknown.

OBJECTIVE

To analyse a large national cohort of patients with AS to determine the overall cancer risk in AS as a background to the future introduction of new treatments.

METHODS

All patients with AS admitted to Swedish hospitals 1965-95 were linked through individual national registration numbers to the Swedish Cancer Register and National Death Register. Standardised incidence ratio (SIR) of cancer risk was calculated in 6621 people, monitored during 67 885 person-years.

RESULTS

No overall increase in cancer risk was found (SIR 1.05, 95% CI 0.94 to 1.17). Rectal cancer was less common (SIR 0.41, 95% CI 0.15 to 0.89) while unspecified kidney cancer was more common (SIR 5.90, 95% CI 1.61 to 15.1). Risks for colon, renal parenchymal, and renal pelvic cancer were not significantly increased. Laryngeal cancer was more common than expected, while lung cancer was not. Risks of haematopoietic malignancies were not increased.

CONCLUSIONS

No overall increase in cancer risk was found. The decreased risk of rectal cancer might be due to local application of NSAIDs, and the increased risk of unspecified kidney cancer to frequent radiological pelvic examinations. If information on disease characteristics, including HLA-B27, was available for individual patients with cancer, risk-benefit analysis of long term effects of new immunomodulation treatment might be improved.

Impairment of respiratory burst in polymorphonuclear leukocytes by extended-spectrum beta-lactamase-producing strains of Klebsiella pneumoniae

The ability of extended-spectrum beta-lactamase (ESBL)-producing and non-ESBL-producing Klebsiella pneumoniae strains to induce a respiratory burst in polymorphonuclear leukocytes (PMNLs) was investigated. Ninety ESBL-producing and 178 non-ESBL-producing Klebsiella pneumoniae isolates were serotyped and their ability to induce a respiratory burst in PMNLs tested by monitoring the cells' chemiluminescence (CL) response. The percentage of isolates inducing high levels of CL response (CL>75%) was significantly higher among non-ESBL producers (52%) than among ESBL producers (32.2%) ( P<0.0001; OR=3.396; 95%CI=2.036-5.664). The median CL response was significantly higher among the non-ESBL producers (76.9%) than among the ESBL producers (52.6%) ( P=0.034). The two groups did not differ in their ability to resist intracellular killing by PMNLs ( P>0.05), with strains inducing high levels of CL response having significantly lower survival rates (31.8% vs. 42.4%) than strains inducing low levels of CL response (164% vs. 200%) ( P<0.01). The frequencies of the K2 and the K25 serotypes were significantly higher among ESBL-producing strains (17.8% and 22.2%, respectively) than among the non-ESBL producers (6.2% and 1.7%, respectively) ( P=0.0057 and P<0.0001). Of the 77 Klebsiella K serotypes, 71 were detectable among the non-ESBL producers, but only 24 were detectable among the ESBL producers. ESBL-producing Klebsiella pneumoniae strains might have a greater pathogenic potential by virtue of their ability to escape the phagocytic activity of PMNLs.

Klebsiella typing: pulsed-field gel electrophoresis (PFGE) in comparison with O:K-serotyping

OBJECTIVE

To compare pulsed-field gel electrophoresis (PFGE) typing and O:K-serotyping of Klebsiella in two different epidemiological settings.

METHODS

One hundred and four bacteremia isolates without known epidemiological relation and 47 isolates from an outbreak in a neonatal intensive care unit (NICU) were K-typed by countercurrent immunoelectrophoresis (CCIE), O-typed by an inhibition enzyme-linked immunosorbent assay method, and typed by pulsed-field gel electrophoresis (PFGE) using the restriction enzyme XbaI.

RESULTS

Typing data for the 104 bacteremia isolates were compared with regard to typability, number of types, maximum number of isolates per type, and the Discriminative Index (DI). O-typing combined with K-typing (DI 0.98) as O:K-serotyping (DI 0.99) gave a very discriminative typing system, whereas O-typing alone was not very discriminative (DI 0.76). PFGE (DI 1.00) was a more discriminative typing method than O:K-serotyping, as it could subdivide 13/22 O:K-serotypes into smaller groups. Isolates with the same PFGE-type had the same O:K-serotype, indicating that isolates with different O- and/or K-types could be expected to be of different PFGE-types. Typing of the 47 isolates from the outbreak in the NICU showed that 38 isolates belonged to a single clone, and that during an epidemic limited in time and space, differences in the electrophoretic patterns of up to five bands between a parental pattern type and a subtype may be found in the PFGE profiles.

CONCLUSIONS

Both O:K-serotyping and PFGE typing are highly discriminative typing methods. PFGE is the most discriminative method and is excellent for typing outbreaks with few isolates. If large numbers of isolates are to be typed, a more convenient strategy might be first to K- or O:K-serotype isolates followed by PFGE typing of possible identical isolates. Since K- or O:K-serotyping is a definitive typing method, while PFGE typing is a comparative one, PFGE cannot, for the time being, replace O:K-serotyping for surveillance purposes.

New pathogenic hypotheses for spondyloarthropathies

Pathogenic hypotheses for spondyloarthropathies are evolving. Several candidates have been added to the list of inciting microorganisms, and genes other than HLA-B27 are under scrutiny. Above all, the chiefly 'immunological' theory of spondyloarthropathies incriminating a cross-reaction between self-proteins and bacterial peptides is giving way to a more 'microbiological' concept in which latent bacteria residing within macrophagic or dendritic cells undergo reactivation through a process facilitated by HLA-B27. This molecule is prone to misfolding, which decreases the presentation of bacterial peptides to the immune system and stimulates the Nf-KB inflammation pathway within infected macrophages and/or dendritic cells. Migration of these infected cells from the mucous membranes to the tissues targeted by spondyloarthropathies, particularly the bone marrow located near entheses, may facilitate transient reactivation of dormant intracellular bacteria by creating a favorable cytokine environment. This environment may include high levels of TGFbeta and IL-10, noted also at other sites that enjoy immune privilege, such as the eye. The reactivation may be stopped by a local response of CD4+ and/or CD8+ T cells at the expense of local inflammation responsible for clinical manifestations. This scenario seems consistent with results from studies of murine models transgenic for the HLA-B27 antigen: exposure to bacteria is necessary to the development of spondyloarthropathy, but the disease occurs even when only the heavy chain of HLA-B27 is present (i.e., beta2-microgloblin is not indispensable). Improved understanding of the mechanisms that confer to some bacterial strains a strong potential for persisting within cells, including macrophagic cells, may open the way toward new treatment approaches capable of complementing antagonists of TNF-alpha and other monokines, which merely suspend the disease process, and antibiotic therapy, which fails to kill dormant bacteria located within cells. Pathogenic hypotheses for spondyloarthropathies are evolving. This review presents the most recent concepts. These concepts have not all received confirmation from experimental data. However, the high degree of consistency among them prompted us to consolidate them into a single picture. Although this approach may yield a motley composite of fact and speculation, it may open up new avenues of thought for rheumatologists interested in the links between chronic intracellular infections and inflammatory joint disease.

Infectious agents in chronic rheumatic diseases

The possible role of infectious microorganisms in the disease process of both arthritis and autoimmunity continue to attract both basic and clinical researchers. However, proving a causal role for these suspects is a very difficult and complicated task. This article provides an update on various mechanisms in which microbes may play roles as inciting or perpetuating factors in the pathogenesis of connective tissue disease. It also focuses on current theories that specific microorganisms may play a role in rheumatoid arthritis and ankylosing spondylitis.

Clinical aspects, outcome assessment, and management of ankylosing spondylitis and postenteric reactive arthritis

The cause of ankylosing spondylitis remains unclear. Proof that this disorder is an autoimmune disease attributable to crossreactivity between bacteria and HLA-B27 is still lacking. Differences in endogenous peptide presentation by HLA-B27 subtypes might be relevant in the etiopathogenesis. Fractures of the osteoporotic spine contribute to morbidity. Spinal cord injury may occur. MR imaging enables identifying sacroiliitis earlier than plain radiography. Sweet syndrome has now been described in patients with ankylosing spondylitis and Crohn disease. Progress has been made in the assessment of ankylosing spondylitis. There are now core sets for different settings and validated instruments for functioning and disease activity that will enable demonstrating efficacy of new therapeutic interventions. The debate continues on classification of postinfectious and reactive arthritis. Bacterial antigens may be found in the inflamed joints; occasionally 16S ribosomal RNA is also demonstrated. Antibiotics seem not to be effective in postenteric reactive arthritis. More than 25 years have now elapsed since the association between ankylosing spondylitis and HLA-B27 was first described in 1973. The cause of this disease is still unknown, but a lot of progress has been made regarding the molecular structure of HLA-B27, the spectrum of disease, the clinical and radiographic assessment of ankylosing spondylitis, and its treatment. Recent advances in research on ankylosing spondylitis are reviewed here.