High rates of clustering of strains causing tuberculosis in Harare, Zimbabwe: a molecular epidemiological study

We examined the pattern of tuberculosis (TB) transmission (i.e., reactivation versus recent transmission) and the impact of human immunodeficiency virus (HIV) infection in Harare, Zimbabwe. Consecutive adult smear-positive pulmonary TB patients presenting to an urban hospital in Harare were enrolled. A detailed epidemiological questionnaire was completed, and tests for HIV type 1 and CD4 cell counts were performed for each patient. Molecular fingerprinting of the genomic DNA recovered from cultures of sputum was performed by two molecular typing methods: spacer oligonucleotide typing (spoligotyping) and analysis of variable number of tandem DNA repeats (VNTRs). A cluster was defined as isolates from two or more patients that shared the same spoligotype pattern or the same VNTR pattern, or both. DNA suitable for typing was recovered from 224 patients. The prevalence of HIV infection was 79%. Of 187 patient isolates (78.6%) typed by both spoligotyping and analysis of VNTRs, 147 were identified as part of a cluster by both methods. By spoligotyping alone, 84.1% of patient isolates were grouped into 20 clusters. The cluster size was generally <8 patient isolates, although three large clusters comprised 68, 25, and 23 patient isolates. A total of 89.4% of the patient isolates grouped into 12 clusters defined by analysis of VNTRs, with 2 large clusters consisting of 127 and 13 patient isolates, respectively. Thirty-six percent of patient isolates with a shared spoligotype and 17% with a shared VNTR pattern were geographically linked within Harare, but they were not linked on the basis of the patient's home district. In a multivariate analysis, there were no independent predictors of clustering, including HIV infection status. Comparison with the International Spoligotype database (Pasteur Institute, Pointe a Pitre, Guadeloupe) demonstrated that our three largest spoligotype clusters are well recognized and ubiquitous in Africa. In this epidemiologically well characterized urban population with a high prevalence of HIV infection, we identified a very high level of strain clustering, indicating substantial ongoing recent TB transmission. Geographic linkage could be detected in a proportion of these clusters. A small group of actively circulating strains accounted for most of the cases of TB transmission.     

Sequencing of the pncA gene in members of the Mycobacterium tuberculosis complex has important diagnostic applications: Identification of a species-specific pncA mutation in "Mycobacterium canettii" and the reliable and rapid predictor of pyrazinamide resistance

Testing for susceptibility to pyrazinamide (PZA) and analysis of the pncA gene sequences of 423 Mycobacterium tuberculosis complex isolates have revealed a unique silent nucleotide substitution that enables the rapid identification of "M. canettii" (proposed name). Moreover, the lack of a defined mutation within the pncA gene strongly suggests that an alternative mechanism is responsible for PZA resistance. Our results indicate that DNA sequencing of the pncA gene has the potential to shorten the turnaround time and increase the accuracy of PZA susceptibility testing of the M. tuberculosis complex.     

Mycobacterium tuberculosis Beijing genotype in Russia: in search of informative variable-number tandem-repeat loci

The Beijing genotype is a globally spread lineage of Mycobacterium tuberculosis. In Russia, these strains constitute half of the local population of M. tuberculosis; they are associated with multidrug resistance and show increased transmissibility. Here, we analyzed traditional and new markers for the rapid and simple genotyping of the Beijing strains. A representative sample of 120 Beijing genotype strains was selected from a local IS6110-restriction fragment length (RFLP) database at the St. Petersburg Pasteur Institute. These strains were subjected to variable-number tandem-repeat (VNTR) typing using 24 loci of a newly proposed format and three hypervariable (HV) loci (QUB-3232, VNTR-3820, and VNTR-4120). Ten of the 27 VNTR loci were monomorphic, while five loci, MIRU26, QUB-26, QUB-3232, VNTR-3820, and VNTR-4120, were the most polymorphic (Hunter Gaston index, >0.5). VNTR typing allowed us to differentiate between two large IS6110-RFLP clusters known to be prevalent across the entire country (clusters B0/W148 and A0) and identified in 27 and 23% of strains, respectively, in the Beijing genotype database. The B0/W148 strains were grouped closely in the VNTR dendrogram and could be distinguished by a characteristic signature of the loci MIRU26 and QUB-26. Consequently, this clinically important IS6110-RFLP variant, B0/W148, likely presents a successful clonal group within the M. tuberculosis Beijing lineage that is widespread in Russia. To conclude, the IS6110-RFLP method and VNTR typing using a reduced set of the most polymorphic loci complement each other for the high-resolution epidemiological typing of the M. tuberculosis Beijing genotype strains circulating in or imported from Russia.     

Molecular characterization of Mycobacterium tuberculosis isolates from different regions of Bulgaria

Mycobacterium tuberculosis isolates from different regions of Bulgaria were studied by a variety of molecular typing tools. Based on spacer oligonucleotide typing (spoligotyping), the 113 strains were subdivided into 35 spoligotypes: 5 unique profiles and 15 profiles shared by two to 29 strains; the Hunter-Gaston diversity index (HGI) was 0.9. Comparison with the international database SITVIT2 at the Institut Pasteur de Guadeloupe showed the presence of two globally distributed shared types, ST53 (25.7%) and ST47 (6.2%). Nineteen (16.8%) and six (5.3%) strains belonged to the ST125 (LAM/S subfamily) and ST41 (LAM7_TUR subfamily) types described in SITVIT2 as ubiquitous/rare and ubiquitous/common types, respectively. Seven spoligoprofiles (12 strains) were not found in the database; two of them constituted new shared types. The Beijing genotype strains were not found in the studied collection in spite of close contacts with Russia in the recent and historical past. Additional subtyping by IS6110-restriction fragment length polymorphism (RFLP) and 12-locus mycobacterial interspersed repetitive unit (MIRU)-variable number of tandem repeat analyses were performed within selected spoligotypes. In particular, MIRU typing showed better discrimination within ST125 than IS6110-RFLP typing (HGI = 0.83 versus 0.39). A high gradient for ST125 in Bulgaria compared to its negligible presence in the global database and neighboring countries leads us to suggest a Bulgarian phylogeographic specificity of this spoligotype. To conclude, this first study of the Bulgarian M. tuberculosis population demonstrated its heterogeneity and predominance of several worldwide-distributed and Balkan-specific spoligotypes.     

Impact of immigration on tuberculosis epidemiology in a low-incidence country

Mycobacterium tuberculosis strains from 349 patients were isolated in western Sweden during the years 2001–2005. Only 26% of the tuberculosis (TB) patients were born in Sweden. All the others were born in any of 42 different countries; 17% in other European countries, 28% in Africa, 16% in Asia, 11% in the Middle East, and 2% in South America. The mean age of the Swedish-born patients was 67 years, while the mean age among the foreign-born patients was 37 years. The male/female ratio was 1.6 among the Swedes and 0.9 among those born abroad. Extrapulmonary manifestations of TB were most common among patients born in Africa while lung infections without extrapulmonary manifestations were most common in patients born in Europe, including Sweden. Spoligotyping showed that patients with T or Beijing strains had more pulmonary TB than extrapulmonary TB, while patients with EAI and CAS strains had a high proportion of extrapulmonary TB. The ancestral and/or evolutionary older PGGI strains were more often isolated from the foreign-born patients than from the Swedish-born patients, who had strains generally being of the evolutionary recent genogroups PGG2/PGG3. We conclude that immigration from countries with a high incidence of TB has a strong impact on the TB epidemiology in western Sweden, a finding that should be taken into account by TB control strategists when developing programmes for eradication of TB in low prevalence settings.     

The assessment of the effect of different intraabdominal pressures used for laparoscopic cholecystectomy surgery on optic nerve sheath diameter: a prospective observational cohort study

Background/aimDuring laparoscopic cholecystectomy operations, increases in intraabdominal, intrathoracic, and intracranial pressures (ICP) can be seen after pneumoperitoneum created for surgical imaging. Orbital ultrasonography (USG), which has been developed in recent years, is a method that can evaluate the ICP by measuring the optic nerve sheath diameter (ONSD) from the eyeball.In our study, we aimed to evaluate whether different intraabdominal pressure values created during laparoscopic cholecystectomy operations correlate with ICP by measuring ONSD.Materials and methodsThe study included a total of 90 patients with American Society of Anesthesiologists (ASA) physical status classification I (ASA I) and II (ASA II) and ages from 18 to 65 years with laparoscopic cholecystectomy planned.After the patients were intubated, at the 5th min, bilateral ONSD measurements were performed. The same measurements were performed at the 15th and 30th min after CO2 insufflation and additionally 10 min after CO2 was released at the end of the operation. During intrabdominal CO2 insufflation, patients with 10 mmHg pressure applied comprised Group 1, patients with 12 mmHg pressure applied comprised Group 2, and patients with 14 mmHg pressure applied comprised Group 3.Results The study was completed with 89 patients, 51 female and 38 males. One patient was excluded from the study due to erroneous values. The variations in ONSD measured in the right-left eye before pneumoperitoneum and at the 15th and 30th min after abdominal CO2 insufflation were observed to be statistically significant (p < 0.01). In all three groups, the right and left eye ONSD values were not identified to be statistically significantly different (p > 0.01).A significant increase was observed in ONSD values in direct proportion to the increase in intraabdominal pressure in patients undergoing laparoscopic cholecystectomy surgery.Conclusion USG-guided ONSD measurements appear be a guide to ensure optimization of intraabdominal pressures and safe anesthesia administration for patients, especially those at risk of ICP increase, during laparoscopic surgery.     

Assessment of psychometric properties,cross-cultural adaptation,and translation of the Turkish version of the ICU mobility scale

Background/aim The aim of the study was to carry out the cultural adaptation and translation of the ICU mobility scale (IMS) into Turkish and research the psychometric properties.Materials and methods This study was based on methodological design. The IMS was translated from English to the Turkish through a regularised translation process. Two physiotherapists assessed patients independently in the coronary intensive care unit. The measures such as construct validity, intra and interrater reliability, and internal consistency of the IMS Turkish version were assessed. Results A total of 70 intensive care patients were included in the study. The intrarater and interrater reliability of the IMS was excellent. The weighted Kappa value was 0.92 (0.87–0.96) for the intrarater reliability, and 0.87 (0.80–0.93) for the interrater reliability. There were significant correlations between the IMS and functional status score for the intensive care unit (r = 0.83), Perme intensive care unit mobility score (r = 0.84), Katz activities of daily living (r = 0.73), handgrip strength (r = 0.62), knee extension strength (r = 0.46), and age (r = –0.44).Conclusion This study suggests that the IMS Turkish version is a reliable and valid scale for assessing functional status and mobility level in ICU patients.