Increase in multidrug-resistant tuberculosis (MDR-TB) in Alberta among foreign-born persons: implications for tuberculosis management

Dimensions of poverty as risk factors for antimicrobial resistant organisms in Canada: a structured narrative review

Background

Few studies have assessed the relationship between poverty and the risk of infection with antimicrobial resistant organisms (AROs). We sought to identify, appraise, and synthesize the available published Canadian literature that analyzes living in poverty and risk of AROs.

Methods

A structured narrative review methodology was used, including a systematic search of three databases: MedLINE, EMBASE and Web of Science for articles pertaining to poverty, and infection with AROs in Canada between 1990 and 2020. Poverty was broadly defined to include economic measures and associated social determinants of health. Based on inclusion and exclusion criteria, there were 889 initial articles, and 43 included in the final review. The final articles were extracted using a standard format and appraised using the Joanna Briggs Institute Levels of Evidence framework.

Results

Of 43 studies, 15 (35%) related to methicillin-resistant Staphylococcus aureus (MRSA). One study found a 73% risk reduction (RR 0.27, 95%CI 0.19–0.39, p =  < 0.0001) in community-acquired MRSA (CA-MRSA) infection for each $100,000 income increase. Results pertaining to homelessness and MRSA suggested transmission was related to patterns of frequent drug use, skin-to-skin contact and sexual contact more than shelter contact. Indigenous persons have high rates of CA-MRSA, with more rooms in the house being a significant protective factor (OR 0.86, p = 0.023). One study found household income over $60,000 (OR 0.83, p = 0.039) in univariate analysis and higher maternal education (OR 0.76, 95%CI 0.63–0.92, p = 0.005) in multivariate analysis were protective for otitis media due to an ARO among children. Twenty of 43 (46.5%) articles pertained to tuberculosis (TB). Foreign-born persons were four times more likely to have resistant TB compared to Canadian-born persons. None of the 20 studies used income in their analyses.

Conclusions

There is an association between higher income and protection from CA-MRSA. Mixed results exist regarding the impact of homelessness and MRSA, demonstrating a nuanced relationship with behavioural risk factors. Higher income and maternal education were associated with reduced ARO-associated acute otitis media in children in one study. We do not have a robust understanding of the social measures of marginalization related to being foreign-born that contribute to higher rates of resistant TB infection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01059-1.

Local Transmission Plays No Important Role in the Occurrence of Multidrug-Resistant Tuberculosis in Immigrants to Canada: An In-depth Epidemiologic Analysis

BACKGROUND

Multidrug-resistant (MDR) tuberculosis has increased among migrants in Canada. The cause(s) of this increase is unknown.

METHODS

We performed a retrospective cohort study in a Canadian province with substantially increased immigration between 1982-2001 and 2002-2019. The proportion of MDR tuberculosis among migrants arriving from high MDR (HMDR) tuberculosis burden countries during these 2 periods was used to estimate the proportion of cases due to immigration versus change in proportion in the country of birth. Epidemiologic, spatiotemporal, and drug resistance pattern data were used to confirm local transmission.

RESULTS

Fifty-two of 3514 (1.48%) foreign-born culture-positive tuberculosis patients had MDR tuberculosis: 8 (0.6%) in 1982-2001 and 44 (2.0%) in 2002-2019. Between time periods, the proportion of MDR tuberculosis among migrants with tuberculosis from HMDR tuberculosis countries increased from 1.11% to 3.62%, P = .003; 31.6% attributable to recent immigration and 68.4% to a higher proportion of MDR tuberculosis in cases arrived from HMDR tuberculosis countries. No cases of MDR tuberculosis were attributable to local transmission.

CONCLUSIONS

In stark contrast to HMDR tuberculosis countries, local transmission plays no important role in the occurrence of MDR tuberculosis in Canada. Improved tuberculosis programming in HMDR tuberculosis countries is urgently needed.

Risk factors for drug-resistant tuberculosis at a referral centre in Toronto, Ontario, Canada: 2010-2016

BACKGROUND

Drug-resistant tuberculosis (TB) poses a major public health concern worldwide. However, no studies have addressed risk factors for drug resistance in Ontario, which has its own unique profile of immigrants. We evaluated demographic and clinical risk factors for drug-resistant TB among patients treated at West Park Healthcare Centre, located in Toronto, Ontario (Canada).

METHODS

All patients who were diagnosed with TB and treated at West Park Healthcare Centre between January 2010 and December 2016 were included in this retrospective cohort study. Characteristics of patients with isoniazid mono-resistant (INH-R) TB and multidrug resistant (MDR) TB were compared to patients with drug-susceptible TB with bivariate and multivariable logistic regression.

RESULTS

Risk factors for INH-R TB included younger age (younger than 35 years), prior TB treatment, non-diabetic and birth in a non-South-East Asian country, but only the latter two factors were significant in multivariable analysis. On the other hand, we found younger generation (younger than 65 years), birth in European region, recent arrival to Canada (fewer than 120 months), prior treatment and human immunodeficiency virus (HIV) infection were associated with MDR-TB, among which younger age (younger than 35 years), more recent immigration (fewer than 24 months), prior treatment and HIV infection were significant in multivariable analysis.

CONCLUSION

These findings may be of use to TB clinicians in the province by informing the initial empiric antibiotic regimen prescribed while awaiting phenotypic drug susceptibility testing and assisting in decisions regarding whether to request rapid molecular drug susceptibility testing.

Antibiotic sensitivity of Mycobacterium tuberculosis isolates; a retrospective study from a Saudi tertiary hospital

OBJECTIVES

This study aims to examine the antibiotic sensitivity of Mycobacterium tuberculosis isolates and its drug resistance. We also evaluated the relationship between demographic characteristics and tuberculosis (TB) drug susceptibilities.

METHODS

A retrospective study was conducted to analyse the antibiotic sensitivity of M. tuberculosis isolates and its resistance to first-line anti-TB drugs. During the period 2008-2013, the medical records of 191 patients from the TB ward and the Out-Patient Department in an Eastern KSA tertiary hospital were reviewed.

RESULTS

We classified the specimens into two categories: extra-pulmonary and pulmonary TB. Among the extra-pulmonary TB specimens, 36.5% were from body fluids, 29.2% from tissue cultures and 5.2% from body abscesses. In case of pulmonary TB, sputum samples accounted for the highest proportion of the specimens (28.6%), followed by bronchial aspirates and pleural fluid (13.2% and 5.7%, respectively). Clinical isolates from women showed higher resistance to ethambutol compared to those from men. Isoniazid showed the highest resistance pattern among all antibiotics tested (17%). Meanwhile, tissue cultures had higher resistance to Isoniazid antibiotic compared to the other specimens.

CONCLUSION

Resistance to first-line TB drugs is higher in extra-pulmonary TB isolates than pulmonary isolates. Nearly one-fourth of all M. tuberculosis clinical strains were resistant to the antibiotics tested in mono-resistant or multi-resistant manners. Women had greater resistance to TB drug ethambutol as compared to men. Meanwhile, extra-pulmonary TB specimens, specifically that from tissue cultures, showed greater resistance to Isoniazid than other clinical specimens.

Towards the elimination of paediatric tuberculosis in high-income, immigrant-receiving countries: a 25-year conventional and molecular epidemiological case study

The epidemiology of tuberculosis (TB) in high-income countries is increasingly dictated by immigration. The influence of this trend on paediatric TB and TB elimination are not well defined.

We undertook a 25-year conventional and molecular epidemiologic study of paediatric TB in Alberta, one of four major immigrant-receiving provinces in Canada. All isolates of Mycobacterium tuberculosis were DNA fingerprinted using standard methodology.

Between 1990 and 2014, 176 children aged 0–14 years were diagnosed with TB. Foreign-born children or Canadian-born children of foreign-born parents accounted for an increasingly large proportion of total cases during the study period (from 32.1% to 89.5%). Of the 78 culture-positive cases, 35 (44.9%) had a putative source case identified by conventional epidemiology, with 34 (97.1%) having a concordant molecular profile. Of the remaining 43 culture-positive cases, molecular profiling identified spatially and temporally related sources in six cases (14.0%). These six children, along with four other children whose source cases were discovered through reverse-contact tracing, had a high morbidity and mortality.

The increasing burden of paediatric TB in both foreign-born children and Canadian-born children of foreign-born parents calls for more timely diagnosis of source cases and more targeted screening for latent TB infection.

Conventional and molecular epidemiology can inform paediatric TB elimination strategy in high-income countrieshttp://ow.ly/mwbn30iY1WF

Effects of Fluroquinolones in Newly Diagnosed, Sputum-Positive Tuberculosis Therapy: A Systematic Review and Network Meta-Analysis

BACKGROUND

Tuberculosis is a major public health problem especially in developing countries, the comparative efficacy and safety of fluroquinolones (FQs) for adult patients with newly diagnosed, sputum-positive tuberculosis remains controversial. We aimed to investigate the benefits and risks of FQs-containing (addition/substitution) regimens in this population.

METHODS

A network meta-analysis was performed to compare FQs (C: ciprofloxacin; O: ofloxacin; Lo: levofloxacin; M: moxifloxacin; G: gatifloxacin) addition/substitution regimen with standard HRZE regimen (ie isoniazid, rifampicin, pyrazinamide and ethambutol) in newly diagnosed, sputum-positive tuberculosis. Medline, Embase and Cochrane Central Register of Controlled Trials were systematically searched, randomized trials with duration longer than 8 weeks were included. The primary outcome was week-8 sputum negativity, and secondary outcomes included treatment failure, serious adverse events and death from all cause.

RESULTS

Twelve studies comprising 6465 participants were included in the network meta-analysis. Löwenstein-Jensen culture method showed that HRZEM (OR 4.96, 95% CI 2.83-8.67), MRZE (OR 1.48, 95% CI 1.19-1.84) and HRZM (OR 1.32, 95% CI 1.08-1.62) had more sputum conversion than HRZE by the eighth week, whereas HRC (OR 0.39, 95% CI 0.19-0.77) and HRZO (OR 0.47, 95% CI 0.24-0.92) were worse than HRZE. Moxifloxacin-containing regimens showed more conversion than HRZE by liquid method at the end of two months. But by the end of treatment, FQs-containing regimens didn't show superiority than HRZE on treatment failure. There were no significant differences between any regimens on other outcomes like serious adverse events and all-cause death.

CONCLUSION

This comprehensive network meta-analysis showed that compared with HRZE, moxifloxacin-containing regimens could significantly increase sputum conversion by the eighth week for patients with newly diagnosed pulmonary tuberculosis while HRC and HRZO regimens were inferior. But all the FQs-containing regimens did not show superiority in other outcomes (such as treatment failure, serious adverse events and all-cause death). Thus, HRZE is still an effective regimen for this population. Although moxifloxacin-containing regimens have deomonstrated their potential, FQs-containing regimens should be used with great caution to avoid widespread FQs-resistance worldwide.

Is early tuberculosis death associated with increased tuberculosis transmission?

INTRODUCTION

Tuberculosis (TB) is now a relatively uncommon disease in high income countries. As such, its diagnosis may be missed or delayed resulting in death before or shortly after the introduction of treatment. Whether early TB death is associated with increased TB transmission is unknown. To determine the transmission risk attributable to early TB death we undertook a case-control study.

METHODS

All adults who were: (1) diagnosed with culture-positive pulmonary TB in the Province of Alberta, Canada between 1996 and 2012, and (2) died a TB-related death before or within the first 60 days of treatment, were identified. For each of these "cases" two sets of "controls" were randomly selected from among culture-positive pulmonary TB cases that survived beyond 60 days of treatment. "Controls" were matched by age, sex, population group, +/- smear status. Secondary cases of "cases" and "controls" were identified using conventional and molecular epidemiologic tools and compared. In addition, new infections were identified and compared in contacts of "cases" that died before treatment and contacts of their smear-matched "controls". Conditional logistic regression was used to find associations in both univariate and multivariate analysis.

RESULTS

"Cases" were as, but not more, likely than "controls" to transmit. This was so whether transmission was measured in terms of the number of "cases" and smear-unmatched or -matched "controls" that had a secondary case, the number of secondary cases that they had or the number of new infections found in contacts of "cases" that died before treatment and their smear-matched "controls".

CONCLUSION

In a low TB incidence/low HIV prevalence country, pulmonary TB patients that die a TB-related death before or in the initial phase of treatment and pulmonary TB patients that survive beyond the initial phase of treatment are equally likely to transmit.

Multidrug and extensively drug-resistant tuberculosis in Canada 1997-2008: demographic and disease characteristics

Setting

Nationwide Canadian public health surveillance.

Objective

Description of demographic features and disease characteristics of drug-resistant tuberculosis (TB) in Canada over a 12 year period.

Design

Continuous surveillance of all cases of culture-confirmed TB in Canada. Demographic and microbiologic features were analyzed and comparisons between drug-susceptible, multidrug-resistant (MDR), and drug-resistant not-MDR were made. Cases of extensively drug resistant TB are described.

Results

15,993 cases of culture-confirmed TB were reported during the study period. There were 5 cases of XDR-TB, 177 cases of MDR-TB, and 1,234 cases of first-line drug resistance not-MDR. The majority of drug-resistant cases were reported in foreign-born individuals, with drug-resistant cases diagnosed earlier post-arrival in Canada compared to drug-susceptible cases. In MDR-TB isolates, there was a high rate of drug-resistance to other first- and second-line drugs, making reliable empiric therapeutic recommendations for MDR-TB difficult. There was a statistically significant association between both MDR and drug-resistance not-MDR, and the risk of a negative treatment outcome (defined as treatment failure, absconded, or treatment ongoing >3 yrs).

Conclusion

Drug-resistance complicates TB management even in developed nations with well-established TB control programs. The predominantly international origin of drug-resistant cases highlights the need for global strategies to combat TB.