Tick-borne lymphadenopathy (TIBOLA) acquired in Southwestern Germany.

BACKGROUND: Tick-borne lymphadenopathy (TIBOLA) was first described in 1997 in a patient in France. The causative agent, Rickettsia slovaca, is transmitted by Dermacentor ticks. CASE PRESENTATION: In southwestern Germany we encountered a patient with a tick bite at the dorsal scalp that resulted in an eschar and nuchal lymphadenopathy. Additionally, fever, malaise as well as elevated inflammatory markers and transaminases occurred. The characteristic clinical picture along with positive antibody testing for rickettsiae of the tick-borne spotted fever group strongly suggest the diagnosis TIBOLA. CONCLUSION: Human rickettsioses are emerging infections. Clinicians should be aware of TIBOLA as a newly described rickettsial disease. As in our case, TIBOLA may be encountered in regions/countries where R. slovaca and Dermacentor ticks are prevalent but autochthonous acquisition was not described before.

Dynamics of adaptive microevolution of hypermutable Pseudomonas aeruginosa during chronic pulmonary infection in patients with cystic fibrosis.

BACKGROUND: In patients with cystic fibrosis (CF), the emergence of hypermutable Pseudomonas aeruginosa drives the selection of P. aeruginosa variants that are efficiently adapted to the inflamed lungs of these patients. OBJECTIVE: To provide a detailed survey of adaptive changes in the physiology of P. aeruginosa during chronic lung infection in patients with CF. METHODS: We performed a comparative proteome and transcriptome analysis of sequential, isogenic isolates recovered over a period of 3-5 years from 3 selected patients with CF. The isolates analyzed included both those with high mutation rates and defects in their methyl-directed mismatch repair system (hereafter, "mutators") and those without such changes (hereafter, "nonmutators"). RESULTS: In addition to attenuation of virulence, the P. aeruginosa adaptation process predominantly affects metabolic pathways. In mutator isolates recovered from patients with end-stage CF lung disease, we observed increases in the transcripts of genes or proteins involved in the metabolism of fatty acids and amino acids and the generation of energy. Of particular interest is the increased expression of genes involved in the following pathways and processes: (1) the anaerobic arginine-deiminase pathway, (2) anaerobic respiration (e.g., nitrate-uptake protein OprF, azurin, and cytochrome c551 peroxidase), (3) microaerobic respiration (e.g., cytochrome oxidase cbb3), and (4) the tricarboxylic acid cycle and glyoxylate shunt. Strikingly, increased transcription of the anaerobic regulator gene anr correlates with the up-regulation of ANR-dependent genes. CONCLUSIONS: These changes indicate an adaptive shift toward constitutive expression of genes required for growth under the nutritional and microaerobic conditions created by suppurative secretions in the lungs of patients with CF. In addition, these results provide important clues about the persistence strategies used by P. aeruginosa during progressive CF lung disease.

Molecular evidence of nosocomial Pneumocystis jirovecii transmission among 16 patients after kidney transplantation.

In recent years, clusters of Pneumocystis jirovecii (formerly Pneumocystis carinii) pneumonia (PCP) among immunocompromised individuals have been reported. Mostly, the source of infections was suspected to be within the clinical settings when transplant recipients and PCP patients shared hospital facilities. We report on a cluster of 16 renal transplant recipients positive for P. jirovecii. None of them received anti-Pneumocystis prophylaxis prior to P. jirovecii detection. Epidemiological studies revealed that 15 of them had received kidney transplants at a German university hospital and attended the same inpatient and outpatient clinic from January through September 2006. Multilocus sequence typing (MLST) was performed on the following genes: ITS1, beta-tub, 26S, and mt26S. P. jirovecii DNA was available from 14 patients and showed identical MLST types among these renal transplant recipients. Surprisingly, one patient who was treated at a different nephrological center and reported no personal contact with patients from the renal transplantation cluster harbored an identical P. jirovecii MLST type. Three HIV-positive patients and one bone-marrow-transplanted hematologic malignancy patient--treated at different medical centers--were used as controls, and different MLST types were revealed. Interestingly, in three of the four previously described regions, new alleles were detected, and one new polymorphism was observed in the mt26S region. The epidemiological data and the genotyping results strongly suggest a nosocomial patient-to-patient transmission of P. jirovecii as the predominant transmission route. Therefore, strict segregation and isolation of P. jirovecii-positive/suspected patients in clinical settings seems warranted.

A German external quality survey of diagnostic microbiology of respiratory tract infections in patients with cystic fibrosis.

BACKGROUND: The goal of this pilot study was to design an external quality assessment (EQA) scheme for German cystic fibrosis (CF) clinical microbiology laboratories. Therefore, a multicentre study of 18 German CF laboratories was performed to evaluate their proficiency in analyzing CF respiratory secretions. METHODS: Simulated clinical specimens containing a set of four frequent CF pathogens, namely two Pseudomonas aeruginosa strains differing in morphotype (mucoid versus non-mucoid) and resistotype, one Staphylococcus aureus strain and one Burkholderia multivorans strain, were distributed to each laboratory. Isolation, identification and antimicrobial susceptibility testing (AST) of any bacterial pathogen present and completion of a questionnaire about applied microbiological protocols were requested. RESULTS: Three of four strains were isolated and identified correctly by almost all laboratories. B. multivorans was once misidentified as Burkholderia cenocepacia. Fourteen laboratories failed to detect the second multidrug resistant P. aeruginosa isolate. AST errors occurred most often for P. aeruginosa 2 followed by B. multivorans, P. aeruginosa 1 and S. aureus. Evaluation of the questionnaires revealed major differences in cultivation and identification techniques applied by the participating laboratories. CONCLUSIONS: A periodical EQA programme for German CF laboratories and standardized microbiological procedures seem to be necessary to advance diagnostic microbiology employed on CF respiratory tract specimens and may help to improve anti-infective treatment and infection control practices for CF patients.

Stage-specific adaptation of hypermutable Pseudomonas aeruginosa isolates during chronic pulmonary infection in patients with cystic fibrosis.

BACKGROUND: Pseudomonas aeruginosa (PA) strains with defective DNA mismatch repair genes generate numerous bacterial variants because of high mutation rates. In cystic fibrosis (CF), such mutator strains may lead to the rapid selection of survivors that are specifically adapted to the hostile environment of the inflamed CF lung. METHODS: Genotypes and phenotypes of 111 PA variants descending from 3 distinct mutator strains obtained from 3 patients with CF were systematically characterized. RESULTS: We demonstrated that PA mutS isolates accumulated in the CF lung during the observation period of 3-6 years, with dominance during the final stage of the disease. Mutator strains from the final stage of disease were multiresistant and had lost a set of established virulence-associated traits, including cytotoxicity for bronchial epithelial cells (Calu-3) and macrophages (J774). This pathoadaptation was associated with the loss of survival capacity in a typical environmental habitat, such as tap water. Strikingly, nonmutator strains that maintained their virulence potential persisted as a minority, probably with a preference for the lower airways. CONCLUSIONS: Mutator strains may evolve from the initially infecting PA strain and generate numerous variants with a loss of destructive virulence factors, probably because of selection for improved survival in the deteriorated CF lung but at the expense of the ability to live freely.

Clonal analysis of Inquilinus limosus isolates from six cystic fibrosis patients and specific serum antibody response.

Inquilinus limosus is a novel Gram-negative bacterium of the subdivision alpha-Proteobacteria recently found in the airways of patients with cystic fibrosis (CF). Here, the authors report on the clinical courses of six CF patients colonized with I. limosus. Five patients suffered from either an acute respiratory exacerbation or a progressive loss of pulmonary function, whereas one patient was in a stable clinical situation. This study focused on two aims: (i) the clonal analysis of I. limosus isolates by random amplified polymorphic DNA (RAPD)-PCR, and (ii) the clarification of whether the presence of I. limosus in the respiratory tract is associated with a specific serum antibody response. Serum IgG was detected by immunoblotting using I. limosus whole-cell-lysate proteins as antigens. Sera from healthy blood donors (n=10) and from CF patients colonized with Pseudomonas aeruginosa (n=10) were found to be immunoblot negative. All six Inquilinus-positive patients raised serum IgG antibodies against various I. limosus antigens. Surprisingly, in one patient, a specific I. limosus serum antibody response was already detected 1 year prior to Inquilinus-positive sputum cultures. Two prominent antigens were characterized by MALDI-MS: a 23 kDa protein revealed homology to the outer membrane lipoprotein OmlA of Actinobacillus pleuropneumoniae, and an 18 kDa protein to a protein-tyrosine phosphatase of Burkholderia cepacia. In conclusion, detection of I. limosus is accompanied by a specific serum antibody response and may reflect the infectious/pathogenic potential of I. limosus. Moreover, IgG immunoblotting may be useful to detect early infection with I. limosus and may support the selective cultivation of this novel emerging pathogen.

Nosocomial urosepsis caused by Enterobacter kobei with aberrant phenotype.

Enterobacter kobei is the species of the Enterobacter cloacae complex, which is phenotypically most closely related to the species E. cloacae. This is the first report of infection caused by a new biotype of E. kobei. A patient with a history of urinary bladder operation developed a urosepsis with an Enterobacter isolate displaying the E. cloacae phenotype. The isolate was classified to the species E. kobei by sequence analysis of the 16S-rDNA, 4 protein-coding genes and enterobacterial repetitive intergenic consensus (ERIC)-cluster analysis. E. kobei was originally described to be Voges-Proskauer (VP) negative. However, the isolates of the present case were VP-positive. After analyzing 120 biochemical tests included in the API20E and the Biotype 100 systems, 4 biochemical tests were identified potentially differentiating this new biotype from E. cloacae.

Pitfalls of polymyxin antimicrobial susceptibility testing of Pseudomonas aeruginosa isolated from cystic fibrosis patients.

OBJECTIVES AND METHODS: With their potent activity against Gram-negative bacteria, the polymyxins are important alternative antibiotics for cystic fibrosis (CF) patients. A retrospective evaluation of polymyxin activity against 6001 Pseudomonas aeruginosa, 150 Achromobacter xylosoxidans and 506 Stenotrophomonas maltophilia CF isolates was initiated. In addition, we looked at how polymyxin susceptibility testing was affected by the testing method (agar dilution versus microdilution), the agent (polymyxin E versus polymyxin B), incubation time (24 h versus 48 h) and by different interpretative criteria (German DIN, French FSM, British BSAC). RESULTS: Polymyxin B exhibited reasonable activity against P. aeruginosa (MIC(90)< or =2 mg/L), whereas it was less active against A. xylosoxidans (MIC(90)< or =16 mg/L) and S. maltophilia (MIC(90)< or =16 mg/L). During 2000-2002, polymyxin B resistance in P. aeruginosa, S. maltophilia and A. xylosoxidans was found to be 6.7%, 17.0% and 29.9% (corresponding to 12.4%, 20.7% and 35.4% of infected patients), respectively. When the agar dilution method was used, polymyxin E exhibited higher MICs than polymyxin B. The microdilution method produced lower polymyxin MICs than the agar dilution method. Therefore, the microdilution MICs after prolonged incubation (48 h) and the agar dilution MICs of polymyxin B correlated best (AUC of 0.93, r(2) of 0.44 and s of 0.83). CONCLUSIONS: Polymyxin resistance among common CF pathogens is not rare, thus underlining the necessity of accurate susceptibility testing. When compared with the agar dilution method, it was found that the microdilution method is a valid, rapid and cost effective alternative for the determination of polymyxin activity. The performance of the microdilution method was most reliable after prolonged incubation (48 h) at a susceptibility breakpoint of < or =4 mg/L according to the BSAC guidelines (specificity 91%, sensitivity 89%, 1.5% very major errors).