Nutrient vessel dysfunction can contribute to mucoid degeneration of the posterior cruciate ligament coexisting with lipoma arborescens: A case study

INTRODUCTION

With the rapid improvement of magnetic resonance imaging (MRI), mucoid degeneration (MD) of the anterior cruciate ligament (MD-ACL) has become an established disease entity and mechanical factors, such as increased posterior tibial tilt and intercondylar notch impingement, have been proposed. However, symptomatic MD of the posterior cruciate ligament (MD-PCL) remains an orphan disease without any established etiology.

PRESENTATION OF CASE

A man in his 60s exhibited restricted range of motion with knee pain. MRI revealed PCL enlargement with high-signal intensity and tram-track appearance on T2-weighted sagittal images and lipoma arborescens (LA) in the suprapatellar pouch. On gadolinium-enhanced MRI, the distal PCL was not contrasted. Arthroscopy revealed an almost normal expanded appearance with partial loss of the envelope synovium. Debulking operation was performed. Pathological findings revealed intravascular thrombus formation in early lesions of MD, and intraligamentous vascular degeneration and severity of MD were proportional.

DISCUSSION

ACL is susceptible to mechanical external forces from surrounding tissues because of its anatomical features that induce protease expression, resulting in MD-ACL with denatured large aggregating proteoglycans deposition. Conversely, occlusion of nutrient vessels within the ligament was observed in this case of MD-PCL. Coexisting LA likely provoked an inflammatory response with hypercoagulability, resulting in thromboembolism of the envelope synovial nutrient vessel.

CONCLUSION

MD-CL is a disease entity comprising multiple pathologies. Although symptomatic MD-ACL is mainly caused by mechanical factors with a relatively high morbidity rate, nutrient vessel dysfunction can contribute to symptomatic MD-PCL with coexisting LA in middle-aged adults with an extremely low morbidity rate.

Mucoid Staphylococcus haemolyticus: an unheeded multidrug-resistant pathogen

Coagulase-negative Staphylococci (CoNS) are among the most abundant members of human skin microbiome. CoNS have lately been recognized as substantial agents in plethora of infections, especially nosocomial infections in preterm infants and immunocompromised patients. Staphylococcus haemolyticus is the second most common species isolated from blood, and identification is further hindered when there is a deviation in morphology from the classical one. Here, we report an uncommon case of multidrug resistant mucoid S. hemolyticus isolated from blood in a patient of polytrauma. The patient was managed with ceftriaxone-sulbactam, gentamicin, and meropenem as empirical therapy, which was subsequently changed to intravenous vancomycin. The patient showed favorable response to treatment. Mucoid isolates are known to be more virulent and multi-drug resistant than the classical morphotypes. We also conducted systematic review to decipher the prevalence of mucoid S. hemolyticus and linezolid (LZD) resistance in the same. This case highlights the significance of awareness of mucoid phenotypes of Gram-positive cocci for clinical microbiologists to reach accurate identification. Resistance to LZD further underscores the need of restriction policies in hospitals and to roll out antimicrobial stewardship program stringently, so that the growing resistance could be contained.

Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital

INTRODUCTION

The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016.

MATERIAL AND METHODS

Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected.

RESULTS

From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases.

CONCLUSION

This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.

Intraarticular injection of the interphalangeal joint for therapy of digital mucoid cysts

Mucoid cysts are associated with osteoarthritis (OA) of the digital joints and frequently recur after needle drainage, injection, or surgical ablation. This study determined whether intraarticular injection of the adjacent interphalangeal joint rather than the cyst itself might be effective in resolving digital mucoid cysts. Using paired case series design and sterile technique, 25 consecutive OA digital joints with an adjacent mucoid cyst underwent dorsal non-transtendinous intraarticular injection with a 25-gauge needle and 20-mg triamcinolone acetonide, followed by puncture and manual expression of cyst fluid. Patient pain was measured with the 10-cm Visual Analogue Pain Scale prior to the procedure and at 6 months. Cyst resolution was determined at 6 months and 3 years. The subjects were 61.0 ± 7.7 years old and 60% (15/25) female. Mucoid cysts were adjacent to 19 distal interphalangeal, 3 metacarpophalangeal, and 3 interphalangeal joints. Pre-procedural pain was 4.7 ± 1.0; procedural pain was 6.2 ± 0.6 cm, and post-procedural pain at 6 months was 1.2 ± 0.8 cm (74.5% reduction, 95% CI of difference: 3.0 < 3.5 < 4.0 (p < 0.0001)). 84% (21/25) of the cysts resolved at 6 months; however, 60% (15/25) of the mucoid cysts recurred within 3 years and required retreatment (14 adjacent joints re-injected and 1 ablative cyst surgery). No complications were noted. Intraarticular corticosteroid injection using a dorsal non-transtendinous approach of the joint adjacent to a mucoid cyst is effective resolving cysts and reducing pain at 6 months; however, 60% of mucoid cysts reoccur within 3 years and may require reinjection or surgery.Trial registration: This was not a clinical trial.

Role of ultrasound-guided decompression in management of mucoid degeneration of the anterior cruciate ligament

OBJECTIVE

To assess the effectiveness of ultrasound-guided decompression in managing symptomatic mucoid degeneration of the anterior cruciate ligament (ACL).

MATERIALS AND METHODS

Retrospective analysis of 55 patients who underwent ultrasound-guided ACL mucoid degeneration decompression between July 2013 and August 2019. Subjective satisfaction scores were gathered immediately post-procedure for all 55 patients; follow-up satisfaction scores (scale of 0-10, 10 being excellent) were gathered telephonically for 46 patients (83.6%) up to 63 months post-procedure. Follow-up duration of each patient was classified as short (1-6 months), intermediate (7-12 months), or long (more than 12 months) post-procedure. Forty-five patients (81.8%) MRI were retrospectively analyzed and classified into cystic (n = 13, 28.9%), mucoid (n = 11, 24.4%), or mucoid-cystic (21, 46.7%) types. Multivariate logistic regression was used to identify associations between follow-up satisfaction score, follow-up duration, patient age, and type of ACL degeneration.

RESULTS

All patients had immediate marked post-procedure improvement, with excellent (>7/10) satisfaction scores. Forty-six of 55 patients were telephonically followed up: 21 (45.6%) short-term interval, 18 (39.1%) intermediate term, and 7 (15.2%) long-term. Thirty (65.22%) patients had excellent and eight (17.4%) patients had average satisfaction scores at follow-up. Eight (17.4%) patients had poor post-procedure satisfaction scores within six months. There were no significant associations between immediate or follow-up satisfaction score and duration of follow-up, age of patient, or type of ACL degeneration.

CONCLUSION

Ultrasound-guided aspiration, fenestration, and injection are an effective, safe, minimally invasive and radiation-free technique for management of mucoid degeneration of ACL with excellent immediate- and long-term results.

aeruginosa from a cystic fibrosis patient

Chronic mucoid Pseudomonas aeruginosa infections are a major scourge in cystic fibrosis patients. Mucoid P. aeruginosa displays structured alginate-rich biofilms that are resistant to antibiotics. Here, we have assessed the efficacy of a panel of alginate lyases in combating mucoid P. aeruginosa biofilms in cystic fibrosis. Albeit we could not demonstrate alginate degradation by alginate lyases in sputum, we demonstrate that the endotypic alginate lyases, CaAly (from Cellulophaga algicola) and VspAlyVI (from Vibrio sp. QY101) and the exotypic alginate lyases, FspAlyFRB (from Falsirhodobacterium sp. alg1), and SA1-IV (from Sphingomonas sp. A1), indeed inhibit biofilm formation by a mucoid P. aeruginosa strain isolated from the sputum of a cystic fibrosis patient with comparative effect to that of the glycoside hydrolase PslG, a promising candidate for biofilm treatment. We believe that these enzymes should be explored for in vivo efficacy in future studies.

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A P. aeruginosa strain was isolated from the sputum of a cystic fibrosis patient.

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The anti-biofilm efficacy of endotypic and exotypic alginate lyases was assessed.

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Alginate lyases CaAly, VspAlyVI, FspAlyFRB, and SA1-IV inhibited biofilm formation.

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Similar anti-biofilm effect was observed for the glycoside hydrolase, PslG.

Characterization of group A beta-haemolytic streptococcus with mucoid phenotype isolated in a tertiary hospital

INTRODUCTION

The objective of this study is to characterize Streptococcus pyogenes isolates with a mucoid phenotype and to compare them with non-mucoid isolates obtained between April and August 2016.

MATERIAL AND METHODS

Identification and antimicrobial susceptibility were performed in all isolates. The emm type and exotoxin genes speA, speB, speC, speF, speG, speH, speJ, speZ and ssa were analyzed. Clinical and demographic data were collected.

RESULTS

From 96 isolates analyzed, 47% had a mucoid phenotype and 95.5% of them presented speA-speB-speF-speG-ssa genes and emm3 genotype. The main clinical manifestation was pharyngotonsillitis (77.1%) evolving to scarlet fever in 67.5% of the cases.

CONCLUSION

This study describes the circulation of a mucoid phenotype strain with a speA-speB-speF-speG-ssa toxin profile and emm3.1 genotype considered one of the most frequent and virulent of SGA.

Acquired mucoid phenotype of Acinetobacter baumannii: Impact for the molecular characteristics and virulence

Mucoid phenotype is an important adaptive defense response for Acinetobacter baumannii (A. baumannii). The aim of this study was to analyze the impact of mucoid phenotype for the molecular characteristics and virulence of A. baumannii. We observed that the colonies of mucoid A. baumannii were moist, with an elevated surface, and the wire drawing result was positive. Transmission electron microscopy data showed that the outer wall of the mucoid colonies was not smooth, had protruding pseudopodia, and was surrounded by a layer of unknown material. Antibiotic susceptibility testing showed that the mucoid strains were multidrug resistant. Notably, the mucoid phenotype and antibiotic resistance were not correlated with the amount of biofilm produced by A. baumannii. MLST data demonstrated that the mucoid A. baumannii strains belonged to type ST2. Most (82.6 %, 38/46) of the multidrug-resistant nonmucoid strains also belonged to the molecular type ST2 and to other types, including ST129, ST158, ST195, ST80 and ST3. Moreover, mucoid A. baumannii strains were more virulent than nonmucoid isolates in a mouse model. The comparative transcriptomic data indicated that 15 genes, especially IX87_RS16955 (acnA), IX87_RS10800 (XanP), IX87_RS12875 (GlmM), IX87_RS00885 and IX87_RS12395 (bfr), were possibly associated with the phenotype and virulence of mucoid A. baumannii. In conclusions, the study comprehensively describes the molecular characteristics and virulence regulatory mechanism of mucoid A. baumannii, and provides novel insights for the prevention and treatment of infections associated with these strains.

Anterior translation of the tibia in relation to femur in mucoid degeneration of ACL - An observational study

Background

Mucoid degeneration (MD) of the anterior cruciate ligament (ACL) are a well-known pathological entity.We have encountered several patients with MD of the ACL, found to have a anterior translation of tibia a exceeding 5 mm with an intact ACL. We studied this cohort and investigated the likely cause of this.

Methods

A retrospective search of our department's radiology system to identify all patients referred from the knee orthopaedic clinic for MR imaging over a span of 10 years. All patients had MD within the substance of the ACL and an intact ACL. We evaluated the degree of anterior translation of the tibia (ATT) in relation to the femur in mucoid degeneration of ACL.

Results

We identified 464 consecutive cases. The mean age was 52 years. There was a male predominance of 261 to 203 female. The average PTF measurement was 2.4 mm with a range of 0-20mm. Of the 464 cases, 3 397 patients had an insignificant ATT of < 5 mm. (0mm. 67. 67 67 patients had a ATT >5 mm. Of them, 32.8% had a ATT of 6 mm, 53.7% had a ATT range between 7 and 9 mm, with the remaining 13.4% above 9 mm in length.

Conclusion

It is essential to look for other secondary signs of ACL tears and not only focus on ATT as well as correlate this with clinical findings.

Mucoid Pseudomonas aeruginosa and regional inflammation in the cystic fibrosis lung

BACKGROUND

Pseudomonas aeruginosa is the prominent bacterial pathogen in the cystic fibrosis (CF) lung and contributes to significant morbidity and mortality. Though P. aeruginosa strains initially colonizing the CF lung have a nonmucoid colony morphology, they often mutate into mucoid variants that are associated with clinical deterioration. Both nonmucoid and mucoid P. aeruginosa variants are often co-isolated on microbiological cultures of sputum collected from CF patients. With regional variation in bronchiectasis, tissue damage, inflammation, and microbial colonization, lobar distribution of nonmucoid and mucoid P. aeruginosa variants may impact local microenvironments in the CF lung, but this has not been well-studied.

METHODS

We prospectively collected lobe-specific bronchoalveolar lavage (BAL) fluid from a CF patient cohort (n = 14) using a standardized bronchoscopic protocol where collection was performed in 6 lobar regions. The lobar BAL specimens were plated on P. aeruginosa-selective media and proinflammatory cytokines (IL-1, TNF, IL-6 and IL-8) were measured via cytokine array. Correlations between infecting P. aeruginosa variants (nonmucoid, mucoid, or mixed-variant populations), the lobar regions in which these variants were found, and regional proinflammatory cytokine concentrations were measured.

RESULTS

P. aeruginosa mucoid and nonmucoid variants were homogenously distributed throughout the CF lung. However, infection with mucoid variants (found within single- or mixed-variant populations) was associated with significantly greater regional inflammation. The upper and lower lobes of the CF lung did not exhibit differences in inflammatory cytokine concentrations.

CONCLUSIONS

Mucoid P. aeruginosa infection is a microbial determinant of regional inflammation within the CF lung.

Evolution of Klebsiella pneumoniae with mucoid and non-mucoid type colonies within a single patient

We obtained nine Klebsiella pneumoniae isolates successively isolated from a single patient. Four pairs (M1-M4 and NM1-NM4) obtained simultaneously from the same site showed different colony types, mucoid and non-mucoid, while the final isolate (M5) was isolated alone from the blood and showed a mucoid phenotype. The whole genome of isolate M5 was sequenced de novo using the PacBio RSII system, while the others were sequenced with an Illumina Hiseq4000 and mapped to the genome sequences of M5. To identify insertions or deletions in the cps locus, we amplified and sequenced cps locus genes. We identified insertion sequence (IS) elements in several genes of the cps locus or one amino acid substitution in WcaJ in all non-mucoid isolates. Five additional amino acid alterations in RpsJ, LolE, Lon-2, PpsE, and a hypothetical protein were detected in some mucoid and non-mucoid isolates. Based on the genome data and cps locus sequences, the mucoid phenotype may have been lost or converted into the non-mucoid phenotype because of the insertion of IS elements or amino acid alterations at this locus. We inferred a within-host evolutionary scenario, in which non-mucoid variants emerged repeatedly from mucoid isolates, but may be short-lived because of their low fitness.

Invasive pneumococcal disease caused by mucoid serotype 3 Streptococcus pneumoniae: a case report and literature review

Background

Among the different serotypes of Streptococcus pneumoniae, serotype 3 has received global attention. We report the fatal case of a 76-year-old Japanese man who had an invasive pneumococcal disease associated with pneumonia caused by serotype 3 S. pneumoniae.

Case presentation

The patient had a history of hypertension, laryngeal cancer, chronic obstructive pulmonary disease, and type 2 diabetes mellitus. Following a cerebral arteriovenous malformation hemorrhage, he underwent surgery to remove the hematoma and began rehabilitation. On day 66 of hospitalization, he suddenly developed a fever, and coarse crackles and wheezes were heard in his right lung. A diagnosis of hospital-acquired aspiration pneumonia was made, and initial treatment with piperacillin/tazobactam was started. Teicoplanin was added after S. pneumoniae was isolated from the blood culture, however, the patient died 5 days later. The S. pneumoniae detected in the sputum smear was serotype 3, showed mucoid colonies and susceptibility to penicillins, cephalosporins, carbapenems, and levofloxacin, but resistance to erythromycin.

Conclusion

We experienced a fatal case of pneumonia caused by mucoid serotype 3 S. pneumoniae with a thick capsule. Serotype 3-associated pneumonia may develop a wider pulmonary infiltrative shadow, a prolonged therapeutic or hospitalization course, and a poor outcome. Careful observation and intervention are required, and the use of additional antibiotics or intravenous immunoglobulins should be considered in such cases. Pneumococcal immunization is also an important public health measure to minimize the development of severe infections caused by serotype 3 strains.

Antimicrobial activity of mul-1867, a novel antimicrobial compound, against multidrug-resistant Pseudomonas aeruginosa

Background

There is an urgent need for new antimicrobial compounds to treat various lung infections caused by multidrug-resistant Pseudomonas aeruginosa (MDR-PA).

Methods

We studied the potency of Mul-1867 against MDR-PA isolates from patients with cystic fibrosis, chronic obstructive pulmonary disease, and ventilator-associated pneumonia. The minimal inhibitory concentrations (MICs) and minimum biofilm eliminating concentrations (MBECs), defined as the concentrations of drug that kill 50 % (MBEC₅₀), 90 % (MBEC₉₀), and 100 % (MBEC₁₀₀) of the bacteria in preformed biofilms, were determined by using the broth macrodilution method.

Results

Mul-1867 exhibited significant activity against MDR-PA and susceptible control strains, with MICs ranging from 1.0 to 8.0 µg/mL. Mul-1867 also possesses anti-biofilm activity against mucoid and non-mucoid 24-h-old MDR-PA biofilms. The MBEC₅₀ value was equal to onefold the MIC. The MBEC₉₀ value ranged from two to fourfold the MIC. Moreover, Mul-1867 completely eradicated mature biofilms at the concentrations tested, with MBEC₁₀₀ values ranging between 16- and 32-fold the MIC. Mul-1867 was non-toxic to Madin-Darby canine kidney (MDCK) cells at concentrations up to 256 µg/mL.

Conclusion

Overall, these data indicate that Mul-1867 is a promising locally acting antimicrobial for the treatment and prevention of P. aeruginosa infections.

Anionic fluoroquinolones as antibacterials against biofilm-producing Pseudomonas aeruginosa

Pseudomonas aeruginosa is a common biofilm-forming bacterial pathogen implicated in diseases of the lungs. The extracellular polymeric substances (EPS) of respiratory Pseudomonas biofilms are largely comprised of anionic molecules such as rhamnolipids and alginate that promote a mucoid phenotype. In this Letter, we examine the ability of negatively-charged fluoroquinolones to transverse the EPS and inhibit the growth of mucoid P. aeruginosa. Anionic fluoroquinolones were further compared with standard antibiotics via a novel microdiffusion assay to evaluate drug penetration through pseudomonal alginate and respiratory mucus from a patient with cystic fibrosis.

The extensor carpi ulnaris pseudolesion: evaluation with microCT, histology, and MRI

OBJECTIVE

To determine if magic angle plays a role in apparent central increased signal intensity of the distal extensor carpi ulnaris tendon (ECU) on MRI, to see if histologic findings of tendon degeneration are associated with increased T1 or T2 tendon signal on MR imaging, and to determine the prevalence of the ECU "pseudolesion".

MATERIALS AND METHODS

A standard 3 Tesla protocol was utilized to scan ten cadaveric wrists. A 40 mm length of 10 ECU and four extensor carpi radialis brevis (ECRB) tendons were immersion fixed before microCT scanning. Staining with Alcian blue, Masson's trichrome and Safranin O was performed before light microscopy. Fifty clinical wrist MRIs were also reviewed for the presence of increased T1 and/or T2 signal.

RESULTS

Central increased T1 and/or T2 signal was observed in 9 of 10 cadaveric ECU tendons, but not in ECRB tendons. MicroCT and histology showed inter-tendinous matrix between the two distal heads of the ECU. Increased mucoid degeneration correlated with increased MRI signal intensity. The tendon fibers were at a maximum of 8.39° to the longitudinal axis on microCT. Clinical MRIs showed increased T1 signal in 6%, increased T2 signal in 8%, increased T1 and T2 signal in 80%, and 6% showing no increased signal.

CONCLUSION

Central increased T1 and/or T2 signal in the ECU tendon indicates the presence of normal inter-tendinous ground substance, with increased proteoglycan content (mucoid degeneration) responsible for increased signal intensity. None of the fibers were shown on microCT to approach the magic angle.

A fatal case of iliopsoas abscess caused by Salmonella enterica serovar Choleraesuis that heterogeneously formed mucoid colonies

Salmonella enterica subsp. enterica serovar Choleraesuis, an organism highly adapted to swine, rarely causes invasive human infection. We describe a fatal case of Salmonella ser. Choleraesuis infection developing iliopsoas abscess. A part of organisms recovered from the blood formed mucoid colonies, which became reactive to anti-O antigen antisera after either heat treatment or subculture through semisolid agar.

Impact of alginate-producing Pseudomonas aeruginosa on alveolar macrophage apoptotic cell clearance

Pseudomonas aeruginosa infection is a hallmark of lung disease in cystic fibrosis. Acute infection with P. aeruginosa profoundly inhibits alveolar macrophage clearance of apoptotic cells (efferocytosis) via direct effect of virulence factors. During chronic infection, P. aeruginosa evades host defense by decreased virulence, which includes the production or, in the case of mucoidy, overproduction of alginate. The impact of alginate on innate immunity, in particular on macrophage clearance of apoptotic cells is not known. We hypothesized that P. aeruginosa strains that exhibit reduced virulence impair macrophage clearance of apoptotic cells and we investigated if the polysaccharide alginate produced by mucoid P. aeruginosa is sufficient to inhibit alveolar macrophage efferocytosis. Rat alveolar or human peripheral blood monocyte (THP-1)-derived macrophage cell lines were exposed in vitro to exogenous alginate or to wild type or alginate-overproducing mucoid P. aeruginosa prior to challenge with apoptotic human Jurkat T-lymphocytes. The importance of LPS contamination and that of structural integrity of alginate polymers was tested using alginate of different purities and alginate lyase, respectively. Alginate inhibited alveolar macrophage efferocytosis in a dose- and time-dependent manner. This effect was augmented but not exclusively attributed to lipopolysaccharide (LPS) present in alginates. Alginate-producing P. aeruginosa inhibited macrophage efferocytosis by more than 50%. A mannuronic-specific alginate lyase did not restore efferocytosis inhibited by exogenous guluronic-rich marine alginate, but had a marked beneficial effect on efferocytosis of alveolar macrophages exposed to mucoid P. aeruginosa. Despite decreased virulence, mucoid P. aeruginosa may contribute to chronic airway inflammation through significant inhibition of alveolar clearance of apoptotic cells and debris. The mechanism by which mucoid bacteria inhibit efferocytosis may involve alginate production and synergy with LPS, suggesting that alginate lyase may be an attractive therapeutic approach to airway inflammation in cystic fibrosis and other chronic obstructive pulmonary diseases characterized by P. aeruginosa colonization.