Detection of airborne Mycobacterium tuberculosis complex in high-risk areas of health care facilities in Thailand

<sec id="st1"> <title>SETTING</title> In high-risk areas (sputum collection room in a tuberculosis [TB] clinic, patient rooms in a TB ward, the emergency department and the bronchoscopy unit) in seven health care facilities located in central Thailand. </sec> <sec id="st2"> <title>OBJECTIVE</title> To detect airborne Mycobacterium tuberculosis complex and other environmental parameters using the liquid impinger and real-time quantitative polymerase chain reaction (real-time qPCR) technique in high-risk areas. </sec> <sec id="st3"> <title>DESIGN</title> Cross-sectional study. </sec> <sec id="st4"> <title>RESULTS</title> M. tuberculosis was detected in 3 of 99 (3.0%, 95%CI 0.6-8.6) areas: one sputum collection room and one TB in-patient room in one facility and one sputum collection room in another facility. In these three areas, the M. tuberculosis copy number/m³ ranged from 9.6 to 1671. Lower air change rate (<6 h^-1), higher relative humidity (>65%), and contact with coughing patient(s) were more common in airborne M. tuberculosis-positive areas than in M. tuberculosis-negative areas. </sec> <sec id="st5"> <title>CONCLUSIONS</title> Air sampling using a liquid impinger followed by real-time qPCR is effective for quantitative detection of airborne M. tuberculosis in high-risk areas. Our findings indicate TB risk among health care workers, and suggest that improved ventilation, enhanced appropriate cough etiquette and respiratory protection are needed to mitigate M. tuberculosis transmission. </sec>.

Association of Previous Smoking Habit and Perceived Social Discrimination with the Risk of Multi-Drug Resistant Tuberculosis in Central Nepal

BACKGROUND

Multidrug-resistant tuberculosis (MDR TB) caused by Mycobacterium tuberculosis resistant to both Isoniazid and Rifampicin with or without resistant to other drug, is among the most alarming pandemic problem. The objectives of this study was to assess the risk factors of MDR TB in Central Nepal.

METHODS

A matched case control study was conducted among 186 cases of MDR TB and 372 non-MDR TB controls from central region of Nepal. Pretested questionnaires containing socio-economic, cultural & behavioral; environmental, biological and health service factors were used. Variables significant in bivariate analysis were entered in multiple regression models for further analysis.

RESULTS

After adjusting for confounders, previous smoking habit (aOR= 4.5,(95%CI(1.24-16.2)) (p=0.04), and perceived social discrimination (aOR=5.83,95%CI (1.77-19.71)) (P=0.021) independently predicted greater MDR TB risk.

CONCLUSIONS

Encouraging MDR TB cases for smoking cessation through awareness activities should be a priority. Stigma reduction programs should include the empowerment of patients and communities while promoting TBrelated research for further exploration into the risk factors of TB and associated stigma.

Risk factors of multidrug resistant tuberculosis in central Nepal: a pilot study

INTRODUCTION

Tuberculosis is the most widespread infectious disease in Nepal and poses a serious threat to the health and development of the country. Incidences of drug resistant tuberculosis in Nepal are increasing and this tuberculosis a major threat to successfully controlling tuberculosis.

OBJECTIVE

The general objective of the study was to assess the risk factors of multi-drug resistant tuberculosis among the patients attending the National Tuberculosis Centre, Bhaktpur Nepal.

METHODS

An observational study/ case-control study with a total number of 55 multi-drug resistant tuberculosis cases and 55 controls. The study was conducted among the patient attending in the National Tuberculosis Centre, Bhaktpur Nepal for six months, between May-October 2010. sImulti-drug resistant tuberculosis wasThe collected data was analysed in SPSS 11.5 version. The association between categorical variables were analysed by chi-square tests, OR and their 95% CI were measured.

RESULTS

The total number of patients used for the study was 110, of which among them 55 were cases and 55 were controls . Our study revealed that there were significant associations between history of prior TB MDR-TB OR = 2.799 (95 % CI 1.159 to 6.667) (p = 0.020); smoking habit OR = 2.350 and (95%CI 1.071 to 5.159) (p = 0.032); social stigma social stigma OR 2.655 (95%CI r 1.071 to 5.159) (p = 0.013); knowledge on MDR-TB OR = 9.643 (95% CI 3.339 to 27.846) (p less than 0.001)and knowledge on DOTS Plus OR = 16.714 (95% CI is ranging from 4.656 to 60.008) (p less than 0.001). However, there was no association found between alcohol drinking habits and ventilation in the room.

CONCLUSION

Our study revealed that there were significant associations between history of prior tuberculosis, smoking habit social stigma social stigma, knowledge on multi-drug resistant tuberculosis and knowledge on DOTS Plus with multi-drug resistant tuberculosis However there was no association between alcohol drinking habit and ventilation in room with multi-drug resistant tuberculosis.

katG (SER 315 THR) gene mutation in isoniazid resistant Mycobacterium tuberculosis

BACKGROUND Isoniazid (INH) together with Rifampicin (RFP) forms the cornerstone of a short chemotherapy course for tuberculosis (TB) treatment. Mutation at codon 315 of katG gene is most prevalent in isoniazid resistant Mycobacterium tuberculosis (MTB) and is high in area with high TB incidence. Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) has been found to be a reliable and effective tool for the identification of the specific gene alteration.

OBJECTIVE

The objective of this study was to screen Ser315Thr mutation of KatG gene of INH resistant MTB strain by PCR-RFLP technique.

METHODS

Altogether 37 INHr MTB isolates obtained from German Nepal Tuberculosis Project (GENETUP) Kathmandu Nepal was included in the study. Deoxyribonucleic Acid (DNA) extraction was performed according to protocol of SORPOCLEAN from the culture isolates. Amplification of the fragment with katG codon 315 was performed in a Biometra Thermocycler using primers. The amplified fragment was cleaved with MspI. The restriction fragments obtained were electrophoresed in a 2% agarose gel and were visualized using transilluminator.

RESULTS

The katG Ser315Thr mutation was observed in 23 (62.2%) out of 37 INH resistant isolates. The drug susceptibility profile of INHr MTB isolates showed all isolates to be resistant to INH and RFP whereas 26 and 27 MTB isolates were resistant to Ethambutol (EMB) and Streptomycin (S) respectively. Seventeen (17) patients were harbouring katG gene mutated strain among Ethambutol and Streptomycin resistant cases.

CONCLUSION

The study identified high prevalence of Ser315Thr mutation in katG. The isolates harbouring this mutation were also simultaneously resistant to RFP. Ser315Th could be a potential genetic marker for predicting MDR-TB.

Differentiation of avian pathogenic Escherichia coli (APEC) strains by random amplified polymorphic DNA (RAPD) analysis

Here we describe the application of a random amplified polymorphic DNA (RAPD) analysis for molecular genetic typing avian pathogenic Escherichia coli (APEC) strains. The RAPD technique was shown to be highly reproducible. Stable banding patterns with a high discriminatory capacity were obtained using two different primers. Overall, 55 E. coli strains were analyzed with a RAPD technique. The RAPD analysis showed that the E. coli strains isolated from poultry in Thailand and Sweden could be grouped into 50 of RAPD types by using these two different primer sets. Most of these different E. coli RAPD types were not geographically restricted. There was, as expected, a tendency of higher genetic relationship among E. coli strains isolated from the same farm. It is suggested that the RAPD technique may provide a rapid, low cost, simple and powerful tool to study the clonal epidemiology of avian E. coli infections.

Comparison of Mycobacterium avium complex (MAC) strains from pigs and humans in Sweden by random amplified polymorphic DNA (RAPD) using standardized reagents

Infections with atypical mycobacteria belonging to the Mycobacterium avium/intracellulare complex (MAC) can cause infection in both animals and humans. Using a standardized reagents commercial kit for random amplified polymorphic DNA (RAPD) analysis, 49 MAC strains isolated from 32 slaughter pigs and 17 humans in Sweden were identified and sorted out, yielding 6 RAPD types. By combining the results of RAPD primers 4 and 5 and the primer IS1245A, we found that pigs and humans may be infected with the same types of MAC strains, since 14 strains from humans and 8 strains from pigs were essentially identical and together, comprised RAPD type 2, the largest group of strains (44.8% of strains). With respect to grouping of strains, serotype and RAPD type were uncorrelated, except for serotype 20 and RAPD type 6. Using standardized beads, RAPD analysis is a reproducible technique for typing MAC strains, as the indistinguishable banding patterns obtained with repeated analyses of two isolates from each strain in this study demonstrate. However, primer selection and DNA purity were crucial for differentiating closely related strains.

Application of randomly amplified polymorphic DNA (RAPD) analysis for typing avian Salmonella enterica subsp. enterica

Randomly amplified polymorphic DNA (RAPD) analysis was performed for the molecular genetic typing of 30 Salmonella enterica subsp. enterica strains isolated from chickens and ducks in Thailand. Six different primers were tested for their discriminatory ability. While some of the primers could only differentiate between the different serovars, the use of multiple primers showed that the RAPD method could also subdivide within a given serovar. The Ready-To-Go RAPD analysis beads used, resulted in reproducible and stable banding patterns. As the RAPD technique is simple, rapid and rather cheap, we suggest that it may be a valuable new tool for studying the molecular genetic epidemiology of S. enterica ssp. enterica, both inter- and intra-serovars.

Multiple mutations in the rpoB gene of Mycobacterium leprae strains from leprosy patients in Thailand

A new finding is reported of multiple mutations in the rpoB gene of 9 Mycobacterium leprae strains from leprosy patients in Thailand, who did not respond to therapy even when rifampicin, the main drug in multi-drug therapy was used. By means of sequence analysis of 9 Thai M. leprae strains, various mutations in 289 bps of the rpoB gene revealed forms of mutation never before described, such as multiple mutations (ie, mutation at two, three, six, seven, eight and nine positions in the rpoB gene), most of which were point-mutation substitutions (a few of which were silent), and some insertions. This investigation demonstrates that mutation in the rpoB gene of M. leprae strains from Thailand involves more variety than previously reported for rpoB mutation patterns in rifampicin resistance M. leprae strains.

Identification of Escherichia coli recovered from milk of sows with coliform mastitis by random amplified polymorphic DNA (RAPD) using standardized reagents

A standardized-reagents commercial kit for random amplified polymorphic DNA (RAPD) analysis was used for typing 58 Escherichia coli strains that were recovered from the milk of sows, having coliform mastitis, within a single swineherd in Sweden. Previously, the 58 E. coli strains were characterized serologically and profiled biochemically. They were also evaluated for their serum resistance and their ability to adhere to fibronectin and bovine fetal fibroblasts. The RAPD analysis was fast, easily performed, and required only a nanogram of DNA. The indistinguishable banding patterns obtained with repeated analyses of 2 isolates from each strain demonstrated that RAPD analysis using standardized beads is a technique that provides reproducible results for typing E. coli strains that cause mastitis in sows. The results of the RAPD analyses demonstrated that E. coli sow mastitis strains are highly variable in serotype, biochemical profiles, virulence factors, and RAPD type, and that all 58 strains can be differentiated by means of the RAPD technique. The strains grouped into 24 RAPD types by combining the results of 2 primers, and into 38 groups by combining the results of serotype and RAPD type. No relationship between serotypes, virulence factors and RAPD types was found.

Identification of Escherichia coli recovered from milk of sows with coliform mastitis by random amplified polymorphic DNA (RAPD) using standardized reagents

A standardized-reagents commercial kit for random amplified polymorphic DNA (RAPD) analysis was used for typing 58 Escherichia coli strains that were recovered from the milk of sows, having coliform mastitis, within a single swineherd in Sweden. Previously, the 58 E. coli strains were characterized serologically and profiled biochemically. They were also evaluated for their serum resistance and their ability to adhere to fibronectin and bovine fetal fibroblasts. The RAPD analysis was fast, easily performed, and required only a nanogram of DNA. The indistinguishable banding patterns obtained with repeated analyses of 2 isolates from each strain demonstrated that RAPD analysis using standardized beads is a technique that provides reproducible results for typing E. coli strains that cause mastitis in sows. The results of the RAPD analyses demonstrated that E. coli sow mastitis strains are highly variable in serotype, biochemical profiles, virulence factors, and RAPD type, and that all 58 strains can be differentiated by means of the RAPD technique. The strains grouped into 24 RAPD types by combining the results of 2 primers, and into 38 groups by combining the results of serotype and RAPD type. No relationship between serotypes, virulence factors and RAPD types was found.

Progress and impact of multidrug therapy (MDT) implementation to leprosy control in Thailand

This paper report the progress and impact of MDT implementation to leprosy control in Thailand since 1984 until 1994. By ten years of MDT implementation, number of registered cases dropped from 44,406 in 1984 to only 4,878 cases in 1994. Which made prevalence rate declined 90% from 8.8 to 0.83 per 10,000 population, the detection rate of new case declined from 6.2 to 1.97 per 100,000 population. Total 39,372 cases have been completely covered by MDT and 22,821 cases are under post MDT surveillance with the low relapse rate only 1.46% other indicators showing natural decline of leprosy were increasing in proportion of multibacillary leprosy and mean age at onset of new case of leprosy together with decreasing in proportion of children among new case. Other impact of MDT showing increasing trend of proportion of new case of patient who voluntarily attend treatment centers. However, there were still no satisfactory impact on decreasing in proportion of deformity and duration since onset to the first detection of new case of leprosy.