Proficiency of drug susceptibility testing of Mycobacterium tuberculosis against pyrazinamide: the Swedish experience.

BACKGROUND: Pyrazinamide (PZA) is a key drug in the treatment of tuberculosis (TB), including multidrug-resistant TB. Drug susceptibility testing (DST) of Mycobacterium tuberculosis against PZA is not included in the World Health Organization's yearly proficiency testing. There is an increasing need to establish quality control of PZA DST. OBJECTIVE: To evaluate the performance of PZA DST and to introduce a quality assurance system for the test in Sweden. METHOD: Panels with PZA-susceptible and -resistant isolates were used in three rounds of proficiency testing in all five Swedish clinical TB laboratories and our reference laboratory. All laboratories used the MGIT 960 system. Minimum inhibitory concentrations (MICs) were determined and the pncA gene was sequenced to further characterise the 52 panel strains. RESULTS: Good agreement was seen between the phenotypic PZA DST and pncA sequence data, and MIC determination confirmed high levels of resistance. However, in contrast to other drugs, for which correct proficiency test results were observed, specificity problems occurred for PZA DST in some laboratories. CONCLUSIONS: In Sweden, using panel testing, differences were seen in the proficiency of TB laboratories in correctly identifying PZA susceptibility. Improved results were noted in the third round; PZA has therefore been included in yearly proficiency testing.

[Tracheal adenoid cystic carcinoma treated by complete carinal reconstruction with the help of an ECMO: about a case]. / Carcinome adénoïde kystique trachéal traité par reconstruction complète de la carène sous ECMO: à propos d'un cas.

Primitive tumors of the trachea are rare, accounting for 0.1% of the airway tumors. Cystic adenoid carcinoma (or cylindroma) represents the second most frequent type of tracheal cancers. Histologically speaking, this tumor type is divided in three patterns: cribriform, tubular and solid; it presents a slow growth, perineural invasion and potential local recurrence and metastasis. We presented herein the case of a 56-year-old female suffering from a cystic adenoid carcinoma of the low trachea. She has been treated by carinal resection with negative airway margin and complete reconstruction, with the help of an extra corporeal membrane oxygenation (ECMO).

Salmonella in Black-headed gulls ( Larus ridibundus); prevalence, genotypes and influence on Salmonella epidemiology.

During a period of 3 years, 1998-2000, 1047 faecal swabs from Black-headed gulls were sampled at one location in Southern Sweden. Salmonella spp. was found in 28 individuals (2.7%) and the dominating serotype found was S. Typhimurium (83%). Twenty-five per cent of the Salmonella-infected gulls were later recaptured and re-sampled. We found that Salmonella infection in Black-headed gulls was of short duration, and that infection in this bird species was predominantly expressed as carriage without disease manifestations. All S. Typhimurium isolates were subjected to antibiotic resistance profiling and molecular characterization by pulsed-field gel electrophoresis and IS200 polymerase chain reaction. The S. Typhimurium gull isolates were compared to human and domestic animal isolates of the same serotype and phage type. We found genetic relatedness of S. Typhimurium DT195 isolates from gulls, domestic animals and humans, indicating that Black-headed gulls might play a role in the spread of S. Typhimurium in Sweden.

Maternally derived Cu tolerance in larval fathead minnows: how long does it persist?

Fathead minnow Pimephales promelas larvae were produced by either copper (Cu)-exposed or naïve females and then subjected to a 96 h survival test using Cu concentrations of 400 and 800 microg l(-1). Three survival challenges were conducted: the first survival test featured 0 day-old larvae while the second and third featured 8 and 15 day-old larvae, respectively. The results of this study show that maternally derived Cu tolerance was relatively short-lived as it persisted for <8 days.

Campylobacter jejuni in black-headed gulls (Larus ridibundus): prevalence, genotypes, and influence on C. jejuni epidemiology.

Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.

Salmonella in sub-Antarctica: low heterogeneity in Salmonella serotypes in South Georgian seals and birds.

The number of human visitors to Antarctica is increasing rapidly, and with it a risk of introducing infectious organisms to native animals. To study the occurrence of salmonella serotypes in sub-Antarctic wildlife, faecal samples were collected from gentoo penguins, macaroni penguins, gray-headed albatrosses, black-browed albatrosses and Antarctic fur seals on Bird Island in the South Georgian archipelago during the austral summer of 1996 and 1998. In 1996, S. havana, S. typhimurium and S. enteritidis were isolated from 7% of gentoo penguins and 4% of fur seals. In 1998, however, 22% of fur seals were found to be infected with S. havana, S. enteritidis and S. newport. All isolates, except one, showed identical pulsed-field gel electrophoresis-patterns within each serotype, irrespective of sampling year and animal reservoir. No significant antibiotic resistance was found. The very low heterogeneity in the salmonella isolates found could either indicate a high genetic adaptation of the bacteria to the environment or a recent introduction of salmonella into the area.

Genotyping of the capsule gene cluster (cps) in nontypeable group B streptococci reveals two major cps allelic variants of serotypes III and VII.

Forty group B Streptococcus (GBS) isolates obtained from Europe and the United States previously reported to be nontypeable (NT) by capsule serotype determination were subjected to buoyant density gradient centrifugation. From nearly half of the isolates capsule-expressing variants could be selected. For characterization of the remaining NT-GBS isolates, the capsule operon (cps) was amplified by the long-fragment PCR technique and compared by restriction fragment length polymorphism (RFLP) analysis. The patterns from serotype reference isolates (n = 32) were first determined and used as a comparison matrix for the NT-GBS isolates. Using two restriction enzymes, SduI and AvaII, cluster analysis revealed a high degree of similarity within serotypes but less than 88% similarity between serotypes. However, serotypes III and VII were each split in two distant RFLP clusters, which were designated III(1) and III(2) and VII(1) and VII(2), respectively. Among the isolates that remained NT after repeated Percoll gradient selections, two insertional mutants were revealed. Both were found in blood isolates and harbored insertion sequence (IS) elements within cpsD: one harbored IS1548, and the other harbored IS861. All other NT-GBS isolates could, by cluster analysis, be referred to different serotypes by comparison to the RFLP reference matrix. In pulsed-field gel electrophoresis of SmaI-restricted chromosomal DNA, patterns from allelic type 1 and 2 isolates were essentially distributed in separate clusters in serotypes III and VII. A covariation with insertion sequence IS1548 in the hylB gene was suggested for serotype III, since allelic type III(1) harboring IS1548 in hylB, clustered separately. The variation in serotype VII was not dependent on the presence of IS1548, which was not detected at any position in the type VII chromosome.

Isolation and characterization of Campylobacter jejuni subsp. jejuni from macaroni penguins (Eudyptes chrysolophus) in the subantarctic region.

On Bird Island, South Georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for Campylobacter jejuni. C. jejuni subsp. jejuni was recovered from three macaroni penguins (Eudyptes chrysolophus). These isolates, the first reported for the subantarctic region, showed low genetic diversity and high similarity to Northern Hemisphere C. jejuni isolates, possibly suggesting recent introduction to the area.

Identification of two genes, cpsX and cpsY, with putative regulatory function on capsule expression in group B streptococci.

Two divergently transcribed open reading frames: cpsX and cpsY separated by a common regulatory region was identified upstream of the cpsA-D genes involved in polysaccharide capsule biosynthesis in group B streptococci (GBS). We suggest that these genes are involved in the regulation of capsule expression in GBS, since the CpsX protein shares sequence similarities with LytR of Bacillus subtilis, an attenuator of transcription while CpsY has similarity to a wide variety of members of the LysR family of transcriptional regulators. No deletions, insertions, DNA rearrangements, or apparent differences were discovered in the postulated regulatory genes when the gene region was compared in GBS with different capsule phenotypes. Thus, other yet unidentified gene loci may control capsule phase variation in GBS.

Identification of a novel insertion element, IS1548, in group B streptococci, predominantly in strains causing endocarditis.

Hyaluronidase has been postulated to be a virulence factor in group B streptococci (GBS). No hyaluronidase activity was found in 15 of 50 GBS isolates from adults studied. Most of these hyaluronidase-negative strains belonged to serotype III. In strains lacking hyaluronidase activity, an insertion of 1317 nucleotides was found in the hyaluronidase gene. The fragment was cloned and sequenced and found to have characteristics of a novel insertion sequence, designated IS1548. As well as in GBS serotype III, this sequence was found in 3 of 6 serotype II isolates and in all 10 group A streptococcal strains (GAS) tested. Homologies were found with repeated sequences in Streptococcus pneumoniae and with H repeats in Escherichia coli. All GBS strains harboring IS1548 and some GAS strains had one copy of IS1548 located downstream of the C5a peptidase gene. IS1548 was present in 9 of 13 GBS isolates from blood in endocarditis patients and in 3 of 22 vaginally colonizing strains.

Enteropathogenic bacteria in migrating birds arriving in Sweden.

Birds have been thought to play a role in transmitting infectious agents like influenza, Borrelia and Salmonella. To investigate the role of migrating birds in the dispersal of enteropathogenic bacteria, stool samples from 151 wild birds (50 gulls and 101 passerines) just entering Sweden from their winter grounds were analysed for Salmonella spp., Campylobacter spp. and EHEC O157:H7. The thermophilic isolated enteropathogens found were further analysed by antibiograms. Among the 50 gulls examined, we found 2 isolates of Salmonella typhimurium with multiple antibiotic resistance. Three isolates of C. jejuni were found in the 101 stool samples from passerines. We did not isolate EHEC O157:H7 in any of the bird stools examined.

[Mediastinitis after cardiac surgery. A 10-year evaluation (1985-1995)]. / Les médiastinites après chirurgie cardiaque. Bilan sur 10 ans (1985-1995).

UNLABELLED: From June 1985 to May 1995, 9,814 patients were operated for a cardiac procedure with cardiopulmonary by-pass. Mean age was 61,3 years. The most frequent procedure was coronary surgery (45%), followed by valvular surgery (34%) then combined surgery (11%) and other surgery (4%). 66 cases of mediastinitis were observed: 38 from June 1985 to May 1990 (first group), 28 from June 1990 to May 1995 (second group). The changes between the two groups was antibiotic prophylaxis using Cefuroxime in the first group and Cefamandole in the second and also an impairment of general status of the patients in the second group. Staphylococcus remains the most frequent organism in both groups and for Gram negative bacteria was less frequent in the second group. Several risks factors mediastinitis were identified (males, emergency, diabetes mellitus, obesity, redo, patient of first group, duration of Cardiopulmonary by pass for 100 minutes, mechanical ventilation greater than 48 hours) and the most important factor was the need for mechanical ventilation for more than 48 hours. The mortality rate was 39.4% (26 patients). Identified risk factors of mortality were age over 65 years, females, poor constitution, and cardio/thoracic ratio > 0.55. CONCLUSION: Mediastinitis after cardiac surgery remains a serious complication. In this series we observed a decrease of mediastinitis rates, especially in the second group (p < 0.001). In high risk patients, specific preoperative methods of patient care may be able to prevent such complications. When mediastinitis appears, and when debridement is necessary, a cover procedure seems necessary in elderly or poor constitution patients.

[Postoperative autotransfusion and transfusion evaluation in cardiac surgery]. / Autotransfusion postopératoire et bilan transfusionnel en chirurgie cardiaque.

In cardiac surgery, blood retransfusion from the thoracic drainages, though already ancient, still remains controversial either for its quantitative or its qualitative interests. A retrospective study has been conducted, between the 1st january 1992 and the 30th june 1993, over 1.655 consecutive operations. Most of the patients suffered from coronary disease (937) or a valvular disease (605), others had been operated for a combined valvular and coronary revascularization surgery (113). The safety of this technique, guaranteed by strict rules, allowed a "transfusional strategy" which tends to reduce the homologous blood consumption. Twenty-nine percent of all the patients received homologous red cells units and only 23% of the patients operated for a coronary revascularization. This strategy aims to reduce both the risks of blood transfusion and the health cost.

[Cardiac transplantation: clinical results. Apropos of 150 cases]. / Transplantation cardiaque: résultats cliniques. A propos de 150 cas.

This retrospective study reports the clinical results obtained in a series of 150 heart transplantations performed from October 1986 to January 1995. Overall actuarial survival rate, including operative mortality, was 71% and 57% at 1 and 5 years respectively. Despite a certain level of morbidity, the spectacular functional results in this series are emphasized.

Phase-shift of polysaccharide capsule expression in group B streptococci, type III.

The type-specific polysaccharide capsule is an important virulence determinant in group B streptococci (GBS). The previously described inverse relationship between the buoyant density of a GBS-isolate and the capsular thickness was used to assess the frequencies of polysaccharide capsular phase-shift in clinical GBS, type III strains. Shift from intermediate density (ID) of parental strains, to high density (HD), i.e. shift from intermediate capsule thickness to poor encapsulation, was found to range from 1.2 x 10(-3) to 4.8 x 10(-6). Shift from ID to low density (LD), i.e. shift to abundant encapsulation, ranged from 1.9 x 10(-4) to 1.1 x 10(-7). Shifts were reversible in all cases, either directly (HD-->LD or vice versa) or through intermediate forms. Reversion frequencies were in some isolates as high as 10(-1). Phase-shift frequencies differed more than a thousand-fold between compared strains. Differences in phenotypic shift between strains were validated using flow cytometry. Possible modulation of capsule expression by changes in culture conditions was assessed. Variation of temperature, oxygen-tension, and presence of human serum did not affect capsule expression. However, growth at pH below 5.5 decreased the amount of capsule bound native type III polysaccharide, probably through phenotypic modification rather than genetic shift. IS861, an insertion sequence which has been proposed a regulatory function on the GBS capsule expression, was found in multiple copies in the isolates investigated. No differences in copy number or location of IS861 between the differently encapsulated phenotypes were found.

[Surgical treatment of aneurysms of the left ventricle. Immediate and long-term results. Apropos of a consecutive series of 121 cases]. / Traitement chirurgical des anévrysmes du ventricule gauche. Résultats immédiats et éloignés. A propos d'une série consécutive de 121 cas.

From 1978 to 1992, 121 cases of postinfarction left ventricular aneurysm (99 males, 22 females, mean age 60 years) were operated on. The authors insist on a high rate of clinical arhythmogenicity (31.4%) and associated mechanical complications (21%). 76% of patients were in functional NYHA class III or IV. Resection was performed in 90% of patients, plication in 10%. 58% underwent coronary artery bypass grafting (1.7 graft/patient), 16% encircling ventriculotomy, 8% mitral valve replacement and 13% closure of ventricular septal defect. Operative mortality was 14.9% (10% when other mechanical complications where excluded). 5-year survival is 67.9%. Late cardiac deaths are as follow: left ventricular failure (1.8% A/P), Sudden death (1.4% A/P), Myocardial infarction (0.6% A/P). 82% of survivals are in functional NYHA class I or II. Only functional class NYHA III or IV is predictive of late death. We conclude that postinfarction left ventricular aneurysm remains a high risk complication especially when associated with other mechanical complications. When arhythmogenicity is present we suggest rhythmologic surgery and in all cases, complete revascularization.

Phase variation in streptococci of serological group B. Characteristic properties of isolates from human and bovine infection.

Encapsulation is thought to be a critical virulence factor in streptococci of serological group B. In the present study two encapsulated low-density variants could be separated from their unencapsulated original strains by Percoll gradient centrifugation. The original strains had been isolated from human endocarditis and bovine mastitis. Type antigen preparations of the encapsulated human and bovine group B streptococcus reacted with type III- and type IV-specific antiserum, respectively. No comparable reactions could be observed with their unencapsulated parent strains. In contrast to the original strains, the encapsulated variants grew with uniform turbidity in fluid medium and formed diffuse colonies in soft agar. The original strains grew as granular sediment and formed compact colonies in soft agar. In addition, the original strains appeared to have a more hydrophobic surface and showed significantly greater adherence to epithelial cells. In contrast to the nonencapsulated parent strains, the encapsulated variants were less phagocytosed by polymorphonuclear leukocytes. These findings may help our understanding of the pathogenic importance of phase variants in infections with this bacterial organism.