Molecular characterization of a strain of group a streptococcus isolated from a patient with a psoas abscess

Primary tuberculous psoas abscess as a postpartum complication: Case report and literature review

BACKGROUND

Primary psoas abscess is an unusual clinical entity rarely encountered in the postpartum period. Only seven cases have been reported to date. Here, we present a woman with a primary psoas abscess caused by Mycobacterium tuberculosis and occurred 2 months following a normal vaginal birth. We highlight the difficulties in the management of this uncommon condition in light of the relevant literature.

CASE DESCRIPTION

A 34-year-old woman who was previously healthy was presented at 2 months' postpartum with important right sciatica and low back pain without fever. Examination of the abdomen revealed tenderness in the right iliac fossa but obstetric/gynecologic and neurologic examinations were normal. The patient had an elevated C-reactive protein level and computed tomography (CT)-scan demonstrated a large psoas abscess on the right side without sacroiliac or spine abnormalities. Initial posterior lumbar percutaneous drainage was useful, but no pathogens were identified. The patient was discharged home with oral antibiotics therapy (amoxicillin/clavulanate and metronidazole). Four weeks later, the follow-up CT-scan showed a re-accumulation of the abscess cavity. Subsequently, the patient underwent a right anterolateral laparotomy with a retroperitoneal approach for abscess drainage. Again, no microorganisms were found. However, diagnosis of tuberculosis was established on histopathologic study. She was successfully treated with antituberculous drugs with a good outcome.

CONCLUSIONS

Most primary psoas abscesses present with a delay in diagnosis because of the rarity of this infectious disease, the lack of specific symptoms and signs, and its similarity to many differential diagnoses. When suspected, CT-scan and/or magnetic resonance imaging help in making an accurate diagnosis and facilitate percutaneous or open surgical drainage of the abscess. Correct and fast identification of the microorganisms in addition to appropriate usage of antibiotic regimen improves the outcome.

Antalgic Flexion of the Lower Limb: An Unusual Presentation of Aortoiliac Infection with Psoas Muscle Abscess

Psoas abscess with aortoiliac infection is rare. Patients are often symptomatic for a long time before the correct diagnosis is made. The authors report 4 cases in which the presenting symptom was an antalgic flexion of the left thigh. In 2 patients the cause was an aortic graft infection with enteric fistula; in the other 2, infection developed after transfemoral endovascular procedures. Open surgical treatment was performed in 3 cases and percutaneous drainage in 1. One surgical patient with a late diagnosis eventually died of sepsis; the other 3 are alive and well at mean follow-up of 14 months.

Automated identification of medically important bacteria by 16S rRNA gene sequencing using a novel comprehensive database, 16SpathDB

Despite the increasing use of 16S rRNA gene sequencing, interpretation of 16S rRNA gene sequence results is one of the most difficult problems faced by clinical microbiologists and technicians. To overcome the problems we encountered in the existing databases during 16S rRNA gene sequence interpretation, we built a comprehensive database, 16SpathDB (http://147.8.74.24/16SpathDB) based on the 16S rRNA gene sequences of all medically important bacteria listed in the Manual of Clinical Microbiology and evaluated its use for automated identification of these bacteria. Among 91 nonduplicated bacterial isolates collected in our clinical microbiology laboratory, 71 (78%) were reported by 16SpathDB as a single bacterial species having >98.0% nucleotide identity with the query sequence, 19 (20.9%) were reported as more than one bacterial species having >98.0% nucleotide identity with the query sequence, and 1 (1.1%) was reported as no match. For the 71 bacterial isolates reported as a single bacterial species, all results were identical to their true identities as determined by a polyphasic approach. For the 19 bacterial isolates reported as more than one bacterial species, all results contained their true identities as determined by a polyphasic approach and all of them had their true identities as the "best match in 16SpathDB." For the isolate (Gordonibacter pamelaeae) reported as no match, the bacterium has never been reported to be associated with human disease and was not included in the Manual of Clinical Microbiology. 16SpathDB is an automated, user-friendly, efficient, accurate, and regularly updated database for 16S rRNA gene sequence interpretation in clinical microbiology laboratories.

[Two cases of psoas abscesses caused by group A beta-haemolytic streptococcal infection with a cutaneous portal of entry]

BACKGROUND

Psoas abscess is a rare clinical entity that occurs chiefly after intra-abdominal or retroperitoneal infection. We report two cases of psoas abscesses caused by group A beta-haemolytic streptococcal infection having a cutaneous portal of entry.

CASE REPORTS

The first patient, a 50-year-old man, was feverish and had ulcerative and necrotic cutaneous lesions evocative of ecthyma that were progressing for three months and were recently associated with a painful mass in the left iliac fossa, leading to difficulties in walking. The second patient, a 35-year-old woman with a medical history of intravenous drug addiction, was admitted to intensive care for sepsis syndrome following group A beta-haemolytic streptococcal infection with a cutaneous portal of entry (swelling on left lower limb). She remained unaccountably subfebrile 10 days after the start of antibiotic therapy with amoxicillin. Abdominal CAT scans for each patient confirmed the diagnosis of left psoas abscess. For the first patient, the same group A beta-haemolytic streptococcus was isolated in drainage fluid and at the cutaneous injury site. The outcome was favourable in both cases following extensive intravenous antibiotic therapy (amoxicillin) combined with percutaneous drainage (in the first case).

DISCUSSION

Psoas abscess can occur after locoregional infection and the portals of entry are usually gastro-intestinal, musculoskeletal or genitourinary, with many organisms capable of causing such secondary abscesses. Psoas abscess can also be a primary clinical event. Staphylococcus aureus is the most common causative organism. The presented cases comprised secondary psoas abscesses with a cutaneous portal of entry. Since the complete set of three evocative symptoms (prolonged fever, pain and psoitis) is frequently seen late, diagnosis must be made on the basis of prolonged infectious state or unaccountable feverish abdominal pain. Diagnosis is based on abdominal CAT scan and treatment involves the use of appropriate antibiotics as well as percutaneous or surgical drainage of the abscess. The mortality rate in this patient population remains high with survival being dependent on prompt initiation of therapy.

Iliopsoas abscess: an unusual cause of postpartum sepsis

Iliopsoas abscess is uncommon in the postpartum period. This case illustrates the presentation of this unusual cause of postpartum sepsis and highlights difficulties in diagnosis.

Globicatella bacteraemia identified by 16S ribosomal RNA gene sequencing

BACKGROUND

Globicatella are streptococcus-like organisms that have been rarely isolated from clinical specimens. Their epidemiology and clinical significance remain largely unknown.

AIMS

To describe two cases of Globicatella bacteraemia identified by 16S ribosomal RNA (rRNA) gene sequencing.

METHODS

Two unidentified streptococcus-like bacteria isolated from blood cultures of patients were subject to 16S rRNA gene sequencing.

RESULTS

Two cases of Globicatella bacteraemia were identified by 16S rRNA gene sequencing. In the first case, a gram positive coccus was isolated from the blood culture of an 80 year old woman with diabetes mellitus and nosocomial sepsis, who died the day after developing the bacteraemia. The bacterium was unidentified by conventional phenotypic tests, the Vitek (gram positive identification) and the ATB expression (ID32 Strep) systems. In the second case, a similar bacterium was isolated from the blood culture of a 92 year old woman with polymicrobial acute pyelonephritis complicated by septic shock, who subsequently recovered after antibiotic treatment. 16S rRNA gene sequencing of the two isolates showed 0.5% nucleotide difference from that of G. sulfidifaciens and 0.7% nucleotide difference from that of G. sanguinis, indicating that they were Globicatella species.

CONCLUSIONS

Because Globicatella is rarely encountered in clinical microbiology laboratories, it may have been overlooked or misidentified in these cases. 16S rRNA gene sequencing is a useful tool to better characterise the epidemiology and clinical significance of Globicatella.

Clinical, phenotypic, and genotypic evidence for Streptococcus sinensis as the common ancestor of anginosus and mitis groups of streptococci

In 2002, we reported the discovery of a novel species of viridans streptococcus, Streptococcus sinensis. Recently, we reported the isolation of two more strains of S. sinensis. Clinically, S. sinensis is a definite cause of infective endocarditis, a characteristic mainly pertaining to the mitis group of streptococci. Phenotypically, two of the three S. sinensis isolates were Lancefield group F, a characteristic of the anginosus group. However, none of the three strains possess the caramel smell typical of this group of streptococci. Biochemically, S. sinensis was identified in 56% of the time as members of the anginosus group, and in 33% of the time as members of the mitis group. These clinical and phenotypic properties should be governed by the presence/absence or expressivity of particular genes in the S. sinensis genome. Genotypically, phylogenetic analysis using 16S rRNA gene sequences showed that S. sinensis branched out as the first branch in the anginosus group, implying that it is the ancestor of the other members of this group. However, the bootstrap value for S. sinensis clustered with members of the anginosus group is only 47%, meaning that it is often not clustered with members of this group, but the mitis group. Furthermore, the differences in the 16S rRNA gene sequences between S. sinensis and Streptococcus intermedius (3.7%) and those between S. sinensis and Streptococcus gordonii (3.6%) are almost the same. All these indicated that it is very likely that S. sinensis is the common ancestor of the anginosus and mitis groups of streptococci. Complete genome sequencing of S. sinensis and comparative genomics studies on the S. sinensis genome and genomes of members in the anginosus and mitis groups should reveal clues to the underlying genotypic differences that govern the different phenotypic properties of the two groups of streptococci, such as why streptococci of the anginosus group are prone to cause abscess formation but not infective endocarditis as compared to other viridans streptococci.

Continuous ambulatory peritoneal dialysis-related peritonitis associated with Lancefield group G beta-hemolytic streptococcus: report of two cases requiring Tenckhoff catheter removal

We describe the first two cases of continuous ambulatory peritoneal dialysis-related peritonitis associated with Lancefield group G beta-hemolytic streptococci in the literature. Both patients presented with abdominal pain and turbid dialysis effluent with or without fever. Both had concomitant gastrointestinal tract disturbance. Both did not respond to intraperitoneal cefazolin and tobramycin and required removal of the Tenckhoff catheters.