Multidrug-Resistant Escherichia coli from Raw Cow Milk in Namwala District, Zambia: Public Health Implications.

Escherichia coli (E. coli), a major foodborne disease-causing pathogen found in raw cow milk, has even far more reaching public health ramifications as it encodes for antimicrobial resistance (AMR). This study aimed to identify multidrug-resistant (MDR) E. coli from raw cow's milk and evaluate their antimicrobial-resistant profiles. In total, 418 pooled raw cow milk samples were collected from milk collection centers and analysed using standard culture methods to isolate E. coli. Antimicrobial Susceptibility Testing (AST) was conducted using the Kirby Bauer disk diffusion method and PCR was used to identify cefotaxime (CTX) resistant genes. Overall isolation of E. coli was 51.2% (214/418) with MDR observed in 21% (45/214) of isolates across different antibiotic combinations. Resistance was observed towards ampicillin (107/214, 50%), tetracycline (86/214, 40.1%), trimethoprim/sulfamethoxazole (61/214, 28.5%), and amoxicillin/clavulanic acid (CTX) (50/214, 23.4%). Notably, 15% (32/214) resistance to CTX was observed, while 12.6% (27/214) exhibited resistance to imipenem. The blaCTX-M and blaTEM genes were detected in CTX-resistant isolates. The findings of MDR E. coli that harbour blaCTX-M and blaTEM genes in raw cow's milk indicate serious public health risks for consumers.

Antimicrobial resistance profiles of Escherichia coli isolated from laying hens in Zambia: implications and significance on one health.

Background: Antimicrobial resistance (AMR) has been deepening in the layer poultry sector in Zambia partly due to the inappropriate use of antimicrobials. Escherichia coli (E. coli), a commensal and zoonotic bacterium, can potentially be a source of AMR. Objectives: This study assessed the phenotypic AMR profiles of E. coli isolated from the apparent health-laying hens in Lusaka and Copperbelt provinces of Zambia. Methods: A cross-sectional study was conducted between September 2020 and April 2021 in which 365 cloacal swabs were collected from 77-layer farms based in Lusaka and Copperbelt provinces of Zambia. E. coli isolation and identification were done using cultural and biochemical properties and confirmed using the 16S rRNA gene sequencing. Antimicrobial susceptibility testing (AST) was done using the Kirby-Bauer disc-diffusion method. Data analysis was done using WHONET 2020 and Stata v.16.1. Results: Of the 365 samples, E. coli was isolated from 92.9% (n = 339). The AMR was detected in 96.5% (n = 327) of the isolates, of which 64.6% (n = 219) were multidrug-resistant (MDR). E. coli was highly resistant to tetracycline (54.6%) and ampicillin (54%) but showed low resistance to meropenem (0.9%), ceftazidime (6.2%) and chloramphenicol (8.8%). Conclusion: This study found a high prevalence of E. coli resistant to some commonly used antibiotics in poultry, which is a public health concern because of the potential contamination of eggs and layers of chicken meat that enter the food chain. Urgent attention is needed, including strengthening antimicrobial stewardship and surveillance programmes in layer poultry production in Zambia.

Prevalence and antimicrobial resistance patterns of Enterococcus species isolated from laying hens in Lusaka and Copperbelt provinces of Zambia: a call for AMR surveillance in the poultry sector.

Background: The use of antimicrobials in layer poultry production for improved production, growth promotion, prophylaxis and treatment purposes has contributed to the development of antimicrobial resistance (AMR) in poultry. In Zambia, there is a paucity of information on the prevalence and AMR patterns of Enterococcus species isolated from laying hens. Objectives: This study investigated the prevalence and AMR patterns of enterococci isolated in layer hens in Lusaka and Copperbelt provinces of Zambia. Methods: A cross-sectional study was conducted from September 2020 to April 2021. Three hundred and sixty-five pooled cloacal swab samples were collected from 77 layer poultry farms. Enterococci identification and confirmation were performed using Analytical Profile Index (API 20 STREP) and 16S rRNA sequencing, respectively. A panel of nine antibiotics was used for antibiotic susceptibility testing and interpreted according to the CLSI 2020 guidelines. Data were analysed using SPSS version 23 and WHONET 2020. Results: A total of 308 (83%) single Enterococcus species isolates were obtained and showed resistance to tetracycline (80.5%), erythromycin (53.6%), quinupristin/dalfopristin (53.2%), ampicillin (36.72%), vancomycin (32.8%), linezolid (30.2%), ciprofloxacin (11.0%), nitrofurantoin (6.5%) and chloramphenicol (3.9%). The prevalence of enterococci resistant to at least one antibiotic was 99.4% (n = 306), of which 86% (n = 265) were MDR. Conclusions: This study found a high prevalence of antimicrobial-resistant enterococci. The presence of MDR requires urgent intervention and implementation of AMR surveillance strategies and antimicrobial stewardship programmes in layer poultry production in Zambia.

Antibiotic Resistance Patterns of Listeria Species Isolated from Broiler Abattoirs in Lusaka, Zambia.

L. monocytogenes is a public health threat linked to fast foods such as broiler chickens. This study aimed to verify the occurrence of Listeria species in chickens from abattoirs and evaluate their antimicrobial resistance. In total, 150 broiler carcass swabs distributed as cloacal (n = 60), exterior surface (n = 60), and environmental (n = 30) were collected. Listeria species were characterized using biochemical tests and PCR. We conducted antibiotic resistance tests using the disc diffusion and Etest (Biomerieux, Durham, NC, USA) methods. Overall isolation of Listeria species was 15% (23/150) 95% CI (10.16-22.33), 2% (3/150) 95% CI (0.52-6.19) and 13% (20/150) 95% CI (8.53-20.08) came from environmental swabs and carcass swabs, respectively. Proportions of positive Listeria isolates were L. monocytogenes 74% (17/23), L. welshimeri 22% (5/23), and L. innocua 4% (1/23). Listeria species from the exterior carcass swabs was 61% (14/23), cloacal swabs 26% (6/23), and environmental swabs 3% (3/23). L. monocytogenes had the greatest resistance percentage to the following antibiotics: clindamycin (61%, 10/23), tetracycline 30% (7/23), and erythromycin 13%, (3/23). Isolation of L. monocytogenes in relatively high numbers, including the antimicrobial profiles, suggests a potential risk of the pathogen remaining viable in the food continuum and a public health risk to would-be consumers.

Outcomes of multidrug-resistant tuberculosis in Zambia: a cohort analysis.

PURPOSE: The purpose of this study was to establish a baseline for measuring the impact of the programmatic management of drug-resistant TB program by following up on outcomes of all patients diagnosed with multidrug-resistant tuberculosis in Zambia between 2012 and 2014. METHODS: A cohort study of all the MDR-TB patients diagnosed at the national TB reference laboratory from across Zambia. MDR-TB was diagnosed by culture and DST, whereas outcome data were collected in 2015 by patient record checks and home visits. RESULTS: The total number of patients diagnosed was 258. Of those, 110 (42.6%) patients were traceable for this study. There were 67 survivor participants (60.9%); 43 (39.1%) were deceased. Out of the 110 patients who were traced, only 71 (64.5%) were started on second-line treatment. Twenty-nine (40.8%) patients were declared cured and 16.9% were still on treatment; 8.4% had failed treatment. The survival rate was 20.2 per 100 person-years of follow-up. Taking ARVs was associated with a decreased risk of dying (hazard ratio 0.12, p = 0.002). Sex, age, marital status and treatment category were not important predictors of survival in MDR-TB patients. CONCLUSIONS: More than half of the patients diagnosed with MDR-TB were lost to follow-up before second-line treatment was initiated.

The Prevalence of Tuberculosis in Zambia: Results from the First National TB Prevalence Survey, 2013-2014.

BACKGROUND: Tuberculosis in Zambia is a major public health problem, however the country does not have reliable baseline data on the TB prevalence for impact measurement; therefore it was among the priority countries identified by the World Health Organization to conduct a national TB prevalence survey. OBJECTIVE: To estimate the prevalence of tuberculosis among the adult Zambian population aged 15 years and above, in 2013-2014. METHODS: A cross-sectional population-based survey was conducted in 66 clusters across all the 10 provinces of Zambia. Eligible participants aged 15 years and above were screened for TB symptoms, had a chest x-ray (CXR) performed and were offered an HIV test. Participants with TB symptoms and/or CXR abnormality underwent an in-depth interview and submitted one spot- and one morning sputum sample for smear microscopy and liquid culture. Digital data collection methods were used throughout the process. RESULTS: Of the 98,458 individuals who were enumerated, 54,830 (55.7%) were eligible to participate, and 46,099 (84.1%) participated. Of those who participated, 45,633/46,099 (99%) were screened by both symptom assessment and chest x-ray, while 466/46,099 (1.01%) were screened by interview only. 6,708 (14.6%) were eligible to submit sputum and 6,154/6,708 (91.7%) of them submitted at least one specimen for examination. MTB cases identified were 265/6,123 (4.3%). The estimated national adult prevalence of smear, culture and bacteriologically confirmed TB was 319/100,000 (232-406/100,000); 568/100,000 (440-697/100,000); and 638/100,000 (502-774/100,000) population, respectively. The risk of having TB was five times higher in the HIV positive than HIV negative individuals. The TB prevalence for all forms was estimated to be 455 /100,000 population for all age groups. CONCLUSION: The prevalence of tuberculosis in Zambia was higher than previously estimated. Innovative approaches are required to accelerate the control of TB.

Non-tuberculous mycobacteria (NTM) in Zambia: prevalence, clinical, radiological and microbiological characteristics.

BACKGROUND: Non-tuberculous mycobacteria (NTM) infection is an emerging health problem. We present here the Zambia-specific national level data of prevalence, symptomatic, radiological and microbiological characteristics of NTM, using results from a national Tuberculosis (TB) prevalence survey. METHODS: This was a cross-sectional study of the prevalence of NTM among adults aged 15 years and above, who were participants in a national TB prevalence survey. Participants who had either an abnormal chest x-ray or were symptomatic were considered presumptive TB cases and submitted sputum for smear and culture analysis. HIV testing was performed on an opt-out basis. Symptomatic NTM prevalence was estimated from individual level analysis. RESULTS: Of the 6,123 individuals with presumptive TB, 923 (15.1%) were found to have NTM, 13 (0.2%) were MTB/NTM co-infected and 338 (5.5%) were contaminated (indeterminate). The prevalence of symptomatic NTM was found to be 1,477/100,000 [95% CI 1010-1943]. Smear positivity, history of cough or chest pain and HIV positivity were risk factors for NTM. CONCLUSION: This first study to estimate the national prevalence of NTM in Zambia indicates that the burden is high. The NTM occurrence in Zambia constitutes both a public health and ethical issue requiring action from health managers.

Implications of storing urinary DNA from different populations for molecular analyses.

BACKGROUND: Molecular diagnosis using urine is established for many sexually transmitted diseases and is increasingly used to diagnose tumours and other infectious diseases. Storage of urine prior to analysis, whether due to home collection or bio-banking, is increasingly advocated yet no best practice has emerged. Here, we examined the stability of DNA in stored urine in two populations over 28 days. METHODOLOGY: Urine from 40 (20 male) healthy volunteers from two populations, Italy and Zambia, was stored at four different temperatures (RT, 4 degrees C, -20 degrees C & -80 degrees C) with and without EDTA preservative solution. Urines were extracted at days 0, 1, 3, 7 and 28 after storage. Human DNA content was measured using multi-copy (ALU J) and single copy (TLR2) targets by quantitative real-time PCR. Zambian and Italian samples contained comparable DNA quantity at time zero. Generally, two trends were observed during storage; no degradation, or rapid degradation from days 0 to 7 followed by little further degradation to 28 days. The biphasic degradation was always observed in Zambia regardless of storage conditions, but only twice in Italy. CONCLUSION: Site-specific differences in urine composition significantly affect the stability of DNA during storage. Assessing the quality of stored urine for molecular analysis, by using the type of strategy described here, is paramount before these samples are used for molecular prognostic monitoring, genetic analyses and disease diagnosis.