First and Second-Line Anti-Tuberculosis Drug-Resistance Patterns in Pulmonary Tuberculosis Patients in Zambia

Abstract

Background: Drug-resistant tuberculosis has continued to be a serious global health threat defined by complexity as well as higher morbidity and mortality wherever it occurs, Zambia included. However, the paucity of information on drug-susceptibility patterns of both first-line and second-line anti-tuberculosis (anti-TB) drugs, including the new and repurposed drugs used in the management of drug-resistant tuberculosis in Zambia, was the major thrust for conducting this study. Methods: A total of 132 bacteriologically confirmed TB isolates were collected from patients with pulmonary TB during the period from April 2020 to December 2021 in Southern and Eastern Provinces of Zambia. Drug-resistance profiles were determined according to four first-line and five second-line anti-TB drugs. Standard mycobacteriological methods were used to isolate and determine phenotypic drug susceptibility. Data on the participants’ social–demographic characteristics were obtained using a pre-test checklist. Results: Overall, the prevalence of resistance to one or more anti-TB drugs was 23.5% (31/132, 95% CI: 16.5–31.6%). A total of 9.8% (13/132, 95% CI: 5.3–16.2%) of the patients had multidrug-resistant TB and 1.2% were new cases, while 25.5% had a history of being previously treated for TB. Among those with mono-resistant TB strains, isoniazid (INH) resistance was the highest at 9.8% (13/132, 95% CI: 5.3–16.2%). Two (2/31) (6.5%) XDR-TB and one (1/31) (3.2%) pre-XDR-TB cases were identified among the MDR-TB patients. Previously treated patients were 40 times more likely (OR; 40.3, 95% CI: 11.1–146.5%) to have drug-resistant TB than those who had no history of being treated for TB. Conclusion: This study has established a high rate of multidrug-resistant TB and has further identified both pre-XDR- and XDR-TB. There is a need to intensify surveillance of MDR- and XDR-TB to inform future guidelines for effective treatment and monitoring.

Epidemiology of first-and second-line anti-tuberculosis drug resistance in new pulmonary tuberculosis cases in Addis Ababa metropolitan area, Ethiopia

“…Compared to our finding, a higher rate of resistance of M. tuberculosis strains to at least one firstline anti-TB drug among new cases was reported by Yimer SA et al, (30.1%, 2012) [40] in Ethiopia; Mende N et al, (23.5%, 2023) [41] in Zambia; Thapa G et al, (31.1%, 2016) [42] in Nepal; Li Y et al, (34.1%, 2016) [43] in China;…”

“…The rate of MDR-TB identified in this study was 5.8%, (9/156) among new presumptive TB cases and this was congruent to the rate of MDR-TB reported in the previous studies by Tessema B et al, (3.7%, 2012) [28], Yigzaw WB et al, (5.0%, 2021) [40] in Ethiopia; Yonge SA et al, (4.8%, 2017) [46] in Kenya and Dosso M et al, (5.3%, 1999) [32] in Côte d'Ivoire. However, compared to our study findings, a higher rate of MDR-TB was reported in the previous studies by Welekidan LN et al, (11.6%, 2020) [49], and Dagne B et al, (61.9%, 2021) [39] in Ethiopia; Ullah I et al, (9.3%, 2016) [35] in Pakistan; Monde N et al, (9.8%, 2023) [41] in Zambia, Thapa G et al, (15.6%, 2016) [42] in Nepal, Li Y et al, (13.2%, 2016) [43], and Zhou L et al, (18.8%, 2022) [50] in China and Aung WW et al, (18.3%,2015) [51], and Lobie TA et al, (2.3%, 2020) [30] in Ethiopia; Glasauer S et al, (3.3%, 2019) [34] in Germany. Notwithstanding this observation, the WHO estimate of 1.1% of MDR-TB in new TB cases revealed in the 2022 global tuberculosis report is much lower than the findings demonstrated in this study [15].…”

“…However, compared to our study findings, variably a higher rate of INH and a lower rate of STM monoresistance were reported in the previous study by Monde N et al, (9.8% and 0.8%, 2023) [41], respectively, in Zambia.…”

“…Although higher rate resistance against second-line anti-TB drugs was reported in the previous studies by Agonafir M et al, (73.9%, 2010) [53], and Dagne B et al, (5.6%, 2021) [40] in Ethiopia, and Monde N et al, (35.5%, 2023) [41] in Zambia, the absence of resistance to appropriate secondline anti-TB drugs in this study may reflect that the existing treatment of MDR-TB cases in the study area was encouragingly effective. This observation is critical because of the positive implication that initiation of second-line drugs without initial DST might not be beneficial to the patient and requires reemphasizing the need to perform drug susceptibility testing prior to granting anti-TB treatment.…”

Unraveling Dilemmas and Lacunae in the Escalating Drug Resistance of Mycobacterium tuberculosis to Bedaquiline, Delamanid, and Pretomanid

“…9 Other contributing factors to drug resistance include patient non-compliance, emerging mutations, and limited access to diagnosis and treatment. 9 Multi-drug-resistant (MDR) and extensively drug-resistant (XDR) TB strains pose significant treatment challenges, hindering effective care. 10 The emergence of drug-resistant TB, including strains resistant to rifampicin and multiple drugs, poses a significant danger to public health.…”