Standard Genotyping Overestimates Transmission of Mycobacterium tuberculosis among Immigrants in a Low-Incidence Country.

Immigrants from regions with a high incidence of tuberculosis (TB) are a risk group for TB in low-incidence countries such as Switzerland. In a previous analysis of a nationwide collection of 520 Mycobacterium tuberculosis isolates from 2000 to 2008, we identified 35 clusters comprising 90 patients based on standard genotyping (24-locus mycobacterial interspersed repetitive-unit-variable-number tandem-repeat [MIRU-VNTR] typing and spoligotyping). Here, we used whole-genome sequencing (WGS) to revisit these transmission clusters. Genome-based transmission clusters were defined as isolate pairs separated by ≤12 single nucleotide polymorphisms (SNPs). WGS confirmed 17/35 (49%) MIRU-VNTR typing clusters; the other 18 clusters contained pairs separated by >12 SNPs. Most transmission clusters (3/4) of Swiss-born patients were confirmed by WGS, as opposed to 25% (4/16) of the clusters involving only foreign-born patients. The overall clustering proportion was 17% (90 patients; 95% confidence interval [CI], 14 to 21%) by standard genotyping but only 8% (43 patients; 95% CI, 6 to 11%) by WGS. The clustering proportion was 17% (67/401; 95% CI, 13 to 21%) by standard genotyping and 7% (26/401; 95% CI, 4 to 9%) by WGS among foreign-born patients and 19% (23/119; 95% CI, 13 to 28%) and 14% (17/119; 95% CI, 9 to 22%), respectively, among Swiss-born patients. Using weighted logistic regression, we found weak evidence of an association between birth origin and transmission (adjusted odds ratio of 2.2 and 95% CI of 0.9 to 5.5 comparing Swiss-born patients to others). In conclusion, standard genotyping overestimated recent TB transmission in Switzerland compared to WGS, particularly among immigrants from regions with a high TB incidence, where genetically closely related strains often predominate. We recommend the use of WGS to identify transmission clusters in settings with a low incidence of TB.

Post liposuction infections by rapidly growing mycobacteria.

Rapidly growing mycobacteria (RGM) are recognized agents of surgical site infections. Recently, RGM skin and soft tissue infections have been increasingly reported. As symptoms, clinical signs and disease latency remain non-specific and microbiological detection requires targeted growth media, RGM diagnosis remains challenging for clinicians. Appropriate management is often delayed due to lack of awareness of these infections. RGM infections after plastic surgery have also been described in the setting of interventions performed in developing countries, a growing phenomenon commonly known as medical tourism. We describe a case of Mycobacterium chelonae/abscessus infection following liposuction and liposculpture procedures performed in the Dominican Republic and review the literature on this subject.

Effect of mutation and genetic background on drug resistance in Mycobacterium tuberculosis.

Bacterial factors may contribute to the global emergence and spread of drug-resistant tuberculosis (TB). Only a few studies have reported on the interactions between different bacterial factors. We studied drug-resistant Mycobacterium tuberculosis isolates from a nationwide study conducted from 2000 to 2008 in Switzerland. We determined quantitative drug resistance levels of first-line drugs by using Bactec MGIT-960 and drug resistance genotypes by sequencing the hot-spot regions of the relevant genes. We determined recent transmission by molecular methods and collected clinical data. Overall, we analyzed 158 isolates that were resistant to isoniazid, rifampin, or ethambutol, 48 (30.4%) of which were multidrug resistant. Among 154 isoniazid-resistant strains, katG mutations were associated with high-level and inhA promoter mutations with low-level drug resistance. Only katG(S315T) (65.6% of all isoniazid-resistant strains) and inhA promoter -15C/T (22.7%) were found in molecular clusters. M. tuberculosis lineage 2 (includes Beijing genotype) was associated with any drug resistance (adjusted odds ratio [OR], 3.0; 95% confidence interval [CI], 1.7 to 5.6; P < 0.0001). Lineage 1 was associated with inhA promoter -15C/T mutations (OR, 6.4; 95% CI, 2.0 to 20.7; P = 0.002). We found that the genetic strain background influences the level of isoniazid resistance conveyed by particular mutations (interaction tests of drug resistance mutations across all lineages; P < 0.0001). In conclusion, M. tuberculosis drug resistance mutations were associated with various levels of drug resistance and transmission, and M. tuberculosis lineages were associated with particular drug resistance-conferring mutations and phenotypic drug resistance. Our study also supports a role for epistatic interactions between different drug resistance mutations and strain genetic backgrounds in M. tuberculosis drug resistance.

Prevalence of antibodies to Borrelia burgdorferi sensu stricto in humans from a Cuban village.

UNLABELLED: Lyme disease has not been officially reported in Cuba. However, clinical cases have been serologically reported. Seroprevalence survey of Borrelia burgdorferi sensu stricto antibodies in humans in the country has not been conducted. OBJECTIVE: To estimate the prevalence of borrelial antibodies in inhabitants of a village with historically high level of tick infestation. METHODS: Serum specimens from 247 persons randomly selected from the population of the village were examined by IgG Western blot using B31 strain for estimating the prevalence of antibodies profile. RESULTS: A seroprevalence value interval (95% CI) of 0.6%-7.2% was estimated for the studied population. The prevalent borrelial protein bands on immunoblots were 41, 72, 90/93, 34, 47, 60, 58, 56, 65/66 and 31 kDa in a decreasing order of significance. CONCLUSION: These results support the previous serological findings, suggesting the presence of this borreliosis in Cuba.

Prevalence of antibodies to Borrelia burgdorferi sensu stricto in humans from a Cuban village

Lyme disease has not been officially reported in Cuba. However, clinical cases have been serologically reported. Seroprevalence survey of Borrelia burgdorferi sensu stricto antibodies in humans in the country has not been conducted. OBJECTIVE: To estimate the prevalence of borrelial antibodies in inhabitants of a village with historically high level of tick infestation. METHODS: Serum specimens from 247 persons randomly selected from the population of the village were examined by IgG Western blot using B31 strain for estimating the prevalence of antibodies profile. RESULTS: A seroprevalence value interval (95 percent CI) of 0.6 percent-7.2 percent was estimated for the studied population. The prevalent borrelial protein bands on immunoblots were 41, 72, 90/93, 34, 47, 60, 58, 56, 65/66 and 31 kDa in a decreasing order of significance. CONCLUSION: These results support the previous serological findings, suggesting the presence of this borreliosis in Cuba.

Mycobacterium tuberculosis transmission in a country with low tuberculosis incidence: role of immigration and HIV infection.

Immigrants from high-burden countries and HIV-coinfected individuals are risk groups for tuberculosis (TB) in countries with low TB incidence. Therefore, we studied their role in transmission of Mycobacterium tuberculosis in Switzerland. We included all TB patients from the Swiss HIV Cohort and a sample of patients from the national TB registry. We identified molecular clusters by spoligotyping and mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) analysis and used weighted logistic regression adjusted for age and sex to identify risk factors for clustering, taking sampling proportions into account. In total, we analyzed 520 TB cases diagnosed between 2000 and 2008; 401 were foreign born, and 113 were HIV coinfected. The Euro-American M. tuberculosis lineage dominated throughout the study period (378 strains; 72.7%), with no evidence for another lineage, such as the Beijing genotype, emerging. We identified 35 molecular clusters with 90 patients, indicating recent transmission; 31 clusters involved foreign-born patients, and 15 involved HIV-infected patients. Birth origin was not associated with clustering (adjusted odds ratio [aOR], 1.58; 95% confidence interval [CI], 0.73 to 3.43; P = 0.25, comparing Swiss-born with foreign-born patients), but clustering was reduced in HIV-infected patients (aOR, 0.49; 95% CI, 0.26 to 0.93; P = 0.030). Cavitary disease, male sex, and younger age were all associated with molecular clustering. In conclusion, most TB patients in Switzerland were foreign born, but transmission of M. tuberculosis was not more common among immigrants and was reduced in HIV-infected patients followed up in the national HIV cohort study. Continued access to health services and clinical follow-up will be essential to control TB in this population.

Evaluation of a modified culture medium for Borrelia burgdorferi sensu lato

The aim of the present study was to assess the possible use of a modified medium, prepared in the laboratory using the constituents of Barbour-Stonner-Kelly (BSK) medium and medium 199 as base, for the culture of Borrelia strains, comparing the growth of individual strains in this medium and in the BSK-H medium, and the protein profile and antigenic characteristics of Borrelia proteins expressed in these media. A qualitative evaluation of growth of Borrelia species was made with acceptable results (morphology and motility), but during a quantitative evaluation using the three main genospecies of Borrelia, the better results were obtained with a B. burgdorferi sensu stricto strain. The modified medium did not enable the growth of a B. afzelii strain. The protein profile and antigenic characteristic of the expressed proteins in the modified medium were studied with satisfactory results. These results suggest the modified medium as an alternative for the cultivation of Borrelia strains, with some limitations, in poorly-resourced laboratories.

Evaluation of a modified culture medium for Borrelia burgdorferi sensu lato

The aim of the present study was to assess the possible use of a modified medium, prepared in the laboratory using the constituents of Barbour-Stonner-Kelly (BSK) medium and medium 199 as base, for the culture of Borrelia strains, comparing the growth of individual strains in this medium and in the BSK-H medium, and the protein profile and antigenic characteristics of Borrelia proteins expressed in these media. A qualitative evaluation of growth of Borrelia species was made with acceptable results (morphology and motility), but during a quantitative evaluation using the three main genospecies of Borrelia, the better results were obtained with a B. burgdorferi sensu stricto strain. The modified medium did not enable the growth of a B. afzelii strain. The protein profile and antigenic characteristic of the expressed proteins in the modified medium were studied with satisfactory results. These results suggest the modified medium as an alternative for the cultivation of Borrelia strains, with some limitations, in poorly-resourced laboratories(AU)

Evaluation of a modified culture medium for Borrelia burgdorferi sensu lato.

The aim of the present study was to assess the possible use of a modified medium, prepared in the laboratory using the constituents of Barbour-Stonner-Kelly (BSK) medium and medium 199 as base, for the culture of Borrelia strains, comparing the growth of individual strains in this medium and in the BSK-H medium, and the protein profile and antigenic characteristics of Borrelia proteins expressed in these media. A qualitative evaluation of growth of Borrelia species was made with acceptable results (morphology and motility), but during a quantitative evaluation using the three main genospecies of Borrelia, the better results were obtained with a B. burgdorferi sensu stricto strain. The modified medium did not enable the growth of a B. afzelii strain. The protein profile and antigenic characteristic of the expressed proteins in the modified medium were studied with satisfactory results. These results suggest the modified medium as an alternative for the cultivation of Borrelia strains, with some limitations, in poorly-resourced laboratories.

Enhancing the etiologic diagnosis of community-acquired pneumonia in adults using the urinary antigen assay (Binax NOW).

OBJECTIVES: Approximately 40% of community-acquired pneumonia (CAP) remains of unknown etiology. To improve the rate of detection of the causative microbiologic agent, the Binax NOW Streptococcus pneumoniae urinary antigen test (UAT) was evaluated. DESIGN: In this prospective study, 67 adults with CAP were compared with 81 healthy patients to determine sensitivity and specificity of the UAT and its role in improving the etiologic diagnosis of CAP. RESULTS: An etiology could be found for 22 patients (33%) using conventional methods (14 S. pneumoniae, sensitivity 64.3%, 1/81 positive UAT control urine samples, specificity 98.8%). This proportion increased to 33 patients (49%) with the addition of the urinary antigen test (p = 0.039). Pneumococcal infection was diagnosed by the UAT in 24% of our patients without an etiologic identification by conventional methods. CONCLUSIONS: Given its excellent specificity, this test can be considered an important tool for detecting S. pneumoniae in CAP of unknown etiology, enabling the diagnosis of pneumococcal pneumonia in a quarter of cases.