Category Archives: RESEARCH ARTICLES

Antimicrobial susceptibility patterns and their correlate for urinary tract infection pathogens at Kitwe Central Hospital, Zambia.

J Chisanga1, ML Mazaba2,3, J Mufunda2, C Besa1, MC Kapambwe-muchemwa1, S Siziya1
1.Michael Chilufya Sata School of Medicine, Copperbelt University, Ndola, Zambia
2.World Health Organization, Lusaka, Zambia
3.University Teaching Hospital, Lusaka, Zambia
Correspondence: Joshua Chisanga (chisajosh@gmail.com)

Download article

Citation style for this article:
Chisanga J, Mazaba ML, Mufunda J, Besa C, Kapambwe-muchemwa MC, Siziya S. Antimicrobial susceptibility patterns and their correlate for urinary tract infection pathogens at Kitwe Central Hospital, Zambia. Health Press Zambia Bull. 2017;1(1), pp28-37

Inadequate data on antimicrobial susceptibility patterns in the Africa region and indeed in Zambia have led to ineffective empirical treatment before the culture and sensitivity results are made available. The purpose of this study was to determine the antimicrobial susceptibility patterns amongst the most common bacterial causes of UTIs amongst patients presenting at Kitwe Central Hospital (KCH), Zambia.  A 5-year record review of data captured in the laboratory urine register from 2008 to 2013 was conducted. Demographic data, culture and antimicrobial susceptibility data were entered in Epi Info version 7 and analysed using SPSS version 17.0. Associations were determined using the Chi-squared test at the 5% significance level.  A total of 1854 records were extracted from the laboratory register.  The highest frequency of UTI (43.9%) was in the 15–29 years age group. The overall sensitivity patterns indicated that E.coli was mostly sensitive to ciprofloxacin (69.8%), Klebsiella species to ciprofloxacin (68.2%), Proteus species to cefotaxime (66.7%) and Staphylococcus saprophyticus to nitrofuratoin (63.7%). Sensitivity for E. coli to nalidixic acid was higher for males (58.6%) than females (39.5%).  Sensitivity for E. coli to cefotaxime and norfloxacin varied with age (Chi-squared for trend=10.32, p=0.001).  Our results have shown that UTI pathogens isolated at KCH were less than 70% sensitive to the recommended and used antibiotic. Studies to establish highly sensitive antibiotics to UTI pathogens are needed to effectively treat patients.


Introduction

Urinary tract infections (UTIs) account for one of the major reasons for most hospital visits and the determination of the antimicrobial susceptibility patterns of uropathogens will help to guide physicians on the best choice of antibiotics to recommend to affected patients [1]. Bacterial infections that cause community-acquired urinary tract infections and upper respiratory tract infections are most frequently treated empirically. However, an increase in antimicrobial resistance has raised challenges in treating outpatients [2]. The increases in antibiotic resistance of urinary tract pathogens can be attributed mainly to frequent and indiscriminate use of antibiotics [3]. Increasing resistance in bacterial pathogens been reported widely [4]. Despite the widespread availability of antimicrobial agents, UTIs have continued to be increase resistance to antimicrobial agents [5]. The prevalence of antibiotic resistance in UTIs varies according to geographical and regional location [4].  Studies conducted in Pakistan and Washington showed variations in resistance to antibiotics by sex and age group [6,7]. UTIs are caused by different microbial pathogens. The most prevalent bacteria causing UTI are Escherichia coli, Staphylococcus saprophyticus, S. aureus, Proteus sp., Klebsiella pneumoniae, Pseudomonas aeruginosa, and enterococci [1].

The Ministry of Health [Zambia] recommends antibiotic prescription for UTIs to be guided by sensitivity results [8]. The recommended drugs for the treatment of UTI in Zambia are as follows: amoxicillin, nitrofurantoin, nalidixic acid, ciprofloxacin, cefotaxime and ceftriaxone [8]. Limited data on urinary tract pathogens and their in-vitro susceptibility pattern hinder effective empirical treatment. A retrospective study was conducted to determine susceptibility patterns for some of the commonly used antibiotics for the treatment of urinary tract infections at Kitwe Central Hospital, Zambia. 

Methods

The study was conducted at the Kitwe Central Hospital, which is a provincial referral facility for Copperbelt, North Western and Luapula provinces of Zambia. Ethics clearance was obtained from the Tropical Diseases Research Centre Ndola reference number TRC/C4/07/2015 to conduct the study.  

An analysis of secondary data was performed on data captured in the microbiology laboratory register from 2008 to 2013.  The data were captured using Epi info version 7 and analyzed using SPSS version 17.0.  Proportions were compared in 2 x 2 contingency tables using the Yates’ corrected Chi-squared test, while the uncorrected Chi-squared test was used to determine associations in higher contingency tables.  The Chi-squared test for trend was used to determine linear associations.  The cut off point for statistical significance was set at the 5% level.

The culture and sensitivity results that were analysed were results from routine analysis of urine specimen collected from both in- and out-patients. Mid-stream urine
and occasionally urine specimen collected suprapubically were analysed as outlined in the standard operating procedure. Culture was done on CLED agar. Susceptibility testing was done on Mueller Hinton agar using Disk diffusion method with the inoculums suspension in sterile distilled water prepared using a 0.5 McFarland standard.

Results

Table 1 shows susceptibility patterns of commonly isolated UTI pathogens to antibiotics. E.coli isolates were more sensitive to ciprofloxacin (69.8%), norfloxacin (64.0%) and cefotaxime (61.0%) and least to cotrimoxazole (12.7%). Klebsiella species isolates were more sensitive to ciprofloxacin (69.8%), norfloxacin (67.2%) and least to cotrimoxazole (8.4%). Proteus species were  more sensitive to cefotaxime (66.7%), norfloxacin (61.4%), ciprofloxacin (60.6%) and least to co-trimoxazole (17.7%). Staphylococcus saprophyticus isolates were more sensitive to nitrofurantoin (63.7%), ciprofloxacin (63.1%) and norfloxacin (60.5%).

Table 1 Susceptibility patterns of commonly isolated UTI pathogens at Kitwe Central Hospital (Zambia) from 2008-2013

Sensitivity levels for E. coli to antibiotics varied by year. Overall, E.coli was most sensitive to ciprofloxacin (69.8%), norfloxacin (64.0%) and cefotaxime (61.0%) with least sensitivity to co-trimoxazole (12.7%) as shown in Table 2.

Table 2. Susceptibility by year for E.coli to antibiotics at Kitwe Central Hospital (Zambia) from 2008-2013

Apart from ciprofloxacin and co-trimoxazole, sensitivity levels for the other drugs remained constant as shown in table 3.

Table 3 Linear trends in sensitivity levels by year

For both ciprofloxacin and co-trimoxazole, sensitivity levels declined between 2008 and 2013. A unit change in the year corresponded to about 6%(-6.48 for ciprofloxacin and -5.93 for co-trimoxazole).
Sensitivity levels varied by age for cefotaxime (p=0.010) and norfloxacin (p=0.010) as shown in Table 4.

Table 4 E.coli Susceptibility by age group at Kitwe Central Hospital (Zambia) from 2008-2013

Sensitivity levels for cefotaxime linearly decreased with age (Chi-squared test for trend=10.32, p=0.001) but not for nalidixic acid (Chi-squared test for trend=2.20, p=0.138).  The lowest sensitivity level was observed among the 45 years or older patients (48.4% for cefotaxime and 54.5% for norfloxacin). No  significant differences  in antibiotic sensitivity to E. coli were observed between females and males, except for nalidixic acid (p<0.001) with higher levels of sensitivity for males (58.6%) than females (39.5%) as shown in table 5.

Table 5 E.coli Susceptibility by sex at Kitwe Central Hospital (Zambia) from 2008-2013

Discussion

This study provides the information about the antibiotic susceptibility patterns of common bacterial pathogens isolated from urine specimen of patients with urinary tract infections at Kitwe Central Hospital on the Copperbelt province of Zambia. In this study, 1854 urine culture and sensitivity results were analyzed covering the period 2008 to 2013.

Of the 1854 culture results that were analyzed, the most common organisms were   E.coli (46.7%), Klebsiella species (17.1%), Proteus species (15.4%) and Staphylococcus saprophyticus (12.6%). These findings are slightly to what Ekwealor et al found in Nigeria that the most prevalent isolates were S. aureus (28%), E. coli (24.6%), and S. saprophyticus (20%) [1]. Analysis of the susceptibility pattern excluded Enterobacter species, Enterococcus faecalis and Pseudomonas because of small numbers. Susceptibility by age and sex were only done for E.coli because of large numbers.
In the current study, E.coli isolates were more sensitive to ciprofloxacin (69.8%), norfloxacin (64.0%) and cefotaxime (61.0%). The analysis of the trends revealed that apart from ciprofloxacin and co-trimoxazole, sensitivity levels for the other drugs in the table remained constant. For both ciprofloxacin and co-trimoxazole, sensitivity levels declined between 2008 and 2013. A unit change in the year corresponded to about 6%(-6.48 for ciprofloxacin and -5.93 for co-trimoxazole). A study conducted in Tumkur, Bangalore, revealed lower sensitivity level for E.coli to ciprofloxacin (24%), norfloxacin (25.5%) and co-trimoxazole (37%) [10]. Another study conducted in Chandigarh, northern India [11], revealed similar sensitivity for E.coli to ciprofloxacin (62%) among outpatients but higher than 48% sensitivity observed in in-patients.  However, the sensitivity level for E. coli to cefotaxime in the current study was lower than the 96% observed among out-patients and 80% among inpatients. A retrospective study carried out in Brazil revealed rate of resistance of E.coli to ciprofloxacin was higher than expected with highest of 36.0% [12]. A study by Cho et al placed ciprofloxacin (20.7%), levofloxacin (22.7%), co-trimoxazole (34.3%) and ampicillin-clavulanate (42.9%) as the least active substance compared to nitrofurantoin (93.1%) and fosfomycin (100%) [13]. A study by Ahmad et al revealed that E.coli had higher rates of rates of resistance to ampicillin (90%), tetracycline (70%), erythromycin (70%) and Cotrimoxazole (50%) [14]. Fasugba et al concluded that ciprofloxacin resistance in UTI caused by E.coli is increasing hence a need to reconsidered empirical treatment [15].  A study by Bryce et al revealed high rates of resistance ampicillin (23.6%), trimethoprim (8.2%), co-amoxiclav (26.8%) and lower rates for ciprofloxacin (2.1%) and nitrofurantoin (1.3%) [16]. Klebsiella species isolates were more sensitive to ciprofloxacin (68.2%), norfloxacin (67.2%) and the least sensitive to co-trimoxazole (8.4%). The study in Tumkur, Bangalore also showed that Klebsiella species had sensitivity of 63% (ciprofloxacin), 66% (norfloxacin) and 58% (co-trimoxazole) [11]. Proteus species were more sensitive to cefotaxime (66.7%), norfloxacin (61.4%) and ciprofloxacin (60.6%). A study done in Portugal revealed the sensitivity of Proteus species as 2.9% for nitrofurantoin, 75.1%  for norfloxicin,75.0% for ciprofloxacin and 73.2% for cefotaxime [17]. Staphylococcus saprophyticus isolates were more sensitive to nitrofurantoin (63.7%), ciprofloxacin (63.1%) and norfloxacin (60.5%). A study in Iran showed the sensitivity of coagulase negative staphylococci as 100% for ciprofloxacin and nitrofurantoin, 69.2% for co-trimoxazole, 23.1% for cefotaxime and 0% for nalidixic acid [18].

The Sensitivity levels of E.coli varied with age for cefotaxime and norfloxacin.  Furthermore, the sensitivity variation was linearly related to age for cefotaxime suggesting that the drug should be limited to younger age groups of <15 years.  Although no similar pattern emerged for norfloxacin, the least sensitivity was observed in the 45 years or older age group, indicating that the drug should not be used for persons in this age group. Sensitivity to cefotaxime decreased as age increased and this was the same for nalidixic acid and nitrofurantoin. Cefotaxime had the highest sensitivity in the under 15 years of age (70.6%) and lowest in the 45 years or older age group (48.8%). Chloramphenicol had the highest sensitivity in the 15-29 years age group (53.2%) and lowest in the <15 years age group (30.0%). Ciprofloxacin had highest sensitivity in the under 15 years age group (75.5%) and lowest in the 45 years or older age groups (60.5%). Co-trimoxazole had the highest sensitivity in the 45 years or older age group (17.2%) and the lowest in the under 15 years age group (0.0%). Nalidixic acid had the highest sensitivity in the under 15 years age group (56.5%) and lowest in the 45 years or older age group (33.6%). Nitrofurantoin had the highest sensitivity in the 15-29 years age group (61.2%) and the lowest in the under 15 years age group. Norfloxacin had the highest sensitivity in the   under 15 (80.0%) and lowest in the 45+ age group (54.5%).

The only sex difference in sensitivity levels was observed for nalidixic acid, with higher sensitivity for males (58.6%) than females (33.8%).  However, the level of sensitivity was too low to recommend the use of nalidixic acid among males only.

A study done in Pakistan on the resistance of E.coli across age groups and sex revealed variation in resistance patterns of E.coli to antibiotics. Nitrofurantoin was about  2-fold more resistant  in males than  females, while trimethoprim,  co-trimoxazole  and  ceftazidime showed 11%  more  resistance in males than females. Ceftriaxone, ciprofloxacin showed 13%, 14%, more resistance in males as compared to females, respectively. E.coli also manifested almost complete resistance to trimethoprim and co-trimoxazole in all the age groups. The isolates from below 40 years male patients and age groups 50-59 and 70-79 showed almost complete resistance to ciprofloxacin, while  it  was  effective  in  half  of male  patients  in  age  groups  40-49  and  60-69.  Nitrofurantoin showed 33% resistance in age groups 0-9, 20-29 and 30-39 and was found almost sensitive in all other age groups.  Ceftriaxone showed 60% resistance in age group 60+. Ceftriaxone was sensitive in   age group 10-19, while it showed variable resistance among other age groups.
Ciprofloxacin, co-trimoxazole and trimethoprim showed variable resistance patterns in all age groups except 40-49 in which these antibiotics were effective among half the female patients [6]. A study done in USA reported that differences in antibiotic susceptibility to common urinary anti-infectives among E. coli isolated from males versus females was meaningful hence recommending that male sex alone cannot be used as a basis for empirical treatment [7].

Our results have shown that the UTI pathogens isolated at KCH were less than 70% sensitive to the recommended and used antibiotic. Studies to establish high sensitive antibiotics to UTI pathogens are needed to effectively treat patients.

Authors’ contributions

JC obtained the data, conducted preliminary analysis and drafted the manuscript. JM revised the manuscript. CB research protocol development, analysed the findings and revised the manuscript. SS interpreted the findings and edited the manuscript MLM reanalyzed the data, interpreted the results and edited the manuscript.

Acknowledgement

We would like to thank the management of Kitwe Central Hospital for allowing us to use their records.

References

  1. Ekwealor PA, Ugwu MC, Ezeobi I, Amalukwe G, Ugwu BC, Okezie U, et al. Antimicrobial evaluation of bacterial isolates from urine specimen of patients with complaints of urinary tract infections in Awka, Nigeria. Int J Microbiol 2016;2016:9740273.
  2. Biedenbach DJ, Badal RE, Huang MY, Motyl M, Singhal PK, Kozlov RS, et al. In Vitro activity of oral antimicrobial agents against pathogens associated with community-acquired upper respiratory tract and urinary tract infections: A five country surveillance study. Infect Dis Ther 2016 ;5:139-53.
  3. Stamm WE. Urinary tract infections and pyelonephritis. In: Isselbacher KJ, Braunwald E, Wilson JD, editors. Harrison’s principles of internal medicine. 13th sed. Vol. New York: McGraw Hill; 1994.
  4. Tambekar DH, Dhanorkar DV, Gulhane SR, Khandelwal VK, Dudhane MN. Antibacterial susceptibility of some urinary tract pathogens to commonly used antibiotics. Afr J Biotechnol 2006;5:1562–5.
  5. Karlowsky JA, Kelly LJ, Thornsberry C, Jones ME, Sahm DF. Trends in antimicrobial resistance among urinary tract infection isolates of Escherichia coli from female outpatients in the United States. Antimicrob Agents Chemother 2002;46:2540–5.
  6. Nerurkar A, Solanky P, Naik SS. Bacterial pathogens in urinary tract infection and antibiotic susceptibility pattern. J Pharm Biomed Sci 2012;21:1-3.
  7. Bashir MF,  Qazi JI,  Ahmad N, Riaz S. Diversity of urinary tract pathogens and  drug resistant isolates of Escherichia coli different age and gender groups of Pakistanis. Trop  J  Pharm Res 2008;7:1025-31.
  8. McGregor JC, Elman MR, Bearden DT, Smith DH. Sex- and age-specific trends in antibiotic resistance patterns of Escherichia coli urinary isolates from outpatients. BMC Fam Pract 2013;14:25.
  9. Ministry of Health, Zambia National Formulary Committee. Standard Treatment Guidelines, Essential Medicines List, Essential Laboratory Supplies for Zambia. 2nd ed. Lusaka, Zambia: Zambia Ministry of Health, 2008.
  10. Karlowsky JA, Lagacé-Wiens PR, Simner PJ, DeCorby MR, Adam HJ, Walkty A, et al. Antimicrobial resistance in urinary tract pathogens in Canada from 2007 to 2009: CANWARD Surveillance Study.Antimicrob Agents Chemother 2011;55:3169–75.
  11. Manjunath GN, Prakash R, Vamseedhar A, Kiran S. Changing trends in the  spectrum of antimicrobial drug resistance pattern of uropathogens isolated from hospitals and community patients with urinary tract infections in Tumkur and Bangalore. Int J Biol Med Res 2011;2:504-7
  12. Mahesh E, Ramesh D, Indumathi VA, Punith K, Raj K, Anupama HA. Complicated urinary tract infection in a tertiary care centre in south India. Al Ameen J Med Sci 2010; 3:120-7.
  13. Linhares I, Raposo T, Rodrigues A, Almeida A. Frequency and antimicrobial resistance patterns of bacteria implicated in community urinary tract infections: a ten-year surveillance study. BMC Infect Dis 2013;13:19.
  14. Amin M, Mehdinejad M, Pourdangchi Z. Study of bacteria isolated from urinary tract infections and determination of their susceptibility to antibiotics. Jundishapur J Microbiol 2009; 2:118-23.
  15. Reis AC, Santos SR, Souza SC, Saldanha MG, Pitanga TN, Oliveira RR. Ciprofloxicin resistance pattern among bacteria isolated from patients with community acquired Urinary tract infection. Rev inst Med Trop Sao Paulo 2016;58:53.
  16. Cho YH, Jung SI, Chung HS. Antimicrobial susceptibilities of extended spectrum beta-lactamaseproducing Escherichia coli and Klebsiella pneumoniae in health care-associated urinary tract infection: focus on susceptibility to fosfomycin. Int Urol Nephrol 2015; 47:1059-7.
  17. Ahmad W, Jamshed F, Ahmad W. Frequency of Escherichia coli in patients with community acquired urinary tract infection and their resistance pattern against some commonly used anti bacterials. J Ayub Med coll Abbottabad 2015;27:333-7.
  18. Fasugba O, Gardner A, Mitchell BG, Mnatzaganian GC. Ciprofloxicin resistance in community and hospital acquired coli urinary tract infections: a systemic review and meta-analysis of observational studies. BMC Infect Dis 2015;15:545.
  19. Bryce A, Hay AD, Lane IF, Thornton HV, Wootton M, Costelloe C. Global prevalence of antibiotic resistance in paediatric urinary tract infections caused by Escherichia coli and association in primary care: systematic review and meta-analysis. BMJ 2016;352:i939
Facebooktwittergoogle_plusredditpinterestlinkedinmail

Anthrax outbreaks and epidemics in Zambia, 1990-2011: A review

S Siziya
Michael Chilufya Sata School of Medicine, Copperbelt University, Ndola, Zambia

Correspondence: Seter Siziya (ssiziya@gmail.com)

Download article

Citation style for this article:
Siziya S. Anthrax outbreaks and epidemics in Zambia, 1990-2011: A review. Health Press Zambia Bull. 2017;1(1) [Inclusive page numbers]

Anthrax is endemic in Zambia. A review was conducted for literature published on the epidemiology of anthrax in Zambia using google, google scholar and PubMed.  A total of 7 publications were obtained using search words: anthrax, Zambia, epidemiology, outbreak and surveillance; and of these, 2 were full PubMed Central articles, 4 were abstracts without full articles and one was a citation.  In Zambia in 1990, out of 220 human cases of anthrax, 19.1% died; between 1991 and 1998, 7.7% of 248 human cases died; between 1999 and 2007, out of 1790 human cases, 4.6% died; and in 2011, the case mortality rate was 1.2% out of 521 human cases.  In Western province of Zambia, the overall cattle:human anthrax ratio was 1:1.47 and a reduction (Slope=0.738, 95% CI [-1.394, -0.083]) in the human case fatality rate was observed between 1999 and 2007.  There is scanty information on anthrax in Zambia.  The cattle:human anthrax infection ratio was lower than the expected ratio of 1:10 suggesting under-reporting of human cases or good outbreak/epidemic control. A reduction in the case fatality rate indicates good case management.  An active surveillance of human cases of anthrax is recommended immediately there is an outbreak of bovine anthrax in order for people to start treatment early and avoid severe forms of anthrax.


Introduction

Anthrax is a disease of public health importance caused by the spore-forming gram-positive rod bacteria, Bacillus anthracis and its spores can remain viable in soil for a long time up to decades [1-5].  Outbreaks of anthrax generally occur after a prolonged hot dry period [6] and low pH [7].  Although there are inconsistencies in reports on effects of season, rainfall, temperature, soil, vegetation, host condition and population density on the epidemiology of anthrax, anecdotal evidence suggests that temperature and rains (or drought) and humidity are primary conditions affecting the seasonal variation of anthrax [8].

Animals are infected when they breathe in or ingest spores found in soil, plants, or water. Similarly, people are infected when they breathe in spores, eat food or drink water containing spores, or get infected when spores enter through broken skin [9]. CDC [10] suggests five forms of anthrax: Cutaneous characterized by a painless skin lesion with surrounding oedema, fever, malaise and lymphadenopathy; Inhalation characterized by a prodrome resembling a viral respiratory illness, hypoxia, dyspnoea or acute respiratory distress, mediastinal widening or pleural effusion; Gastrointestinal characterized by severe abdominal pain and tenderness, nausea, vomiting, hematemesis, bloody diarrhea, anorexia, fever, abdominal swelling and septicaemia; Oropharyngeal characterized by a painless mucosal lesion in the oral cavity or oropharynx, cervical adenopathy, oedema, pharyngitis, fever, and possibly septicaemia; Meningeal characterized by fever, convulsions, coma, or Meningeal signs; and Injection among injecting heroin users in which smoking and snorting heroin have been identified as possible exposure routes for anthrax [11].  The most fatal form of anthrax is the inhalation anthrax [12].  Mortality in untreated cutaneous cases can be up to 20% [13-15], 25-60% of untreated gastrointestinal form of anthrax [16,17] and 99% of untreated pulmonary anthrax cases [13,17].

Although antibiotics are not recommended for prophylaxis for fear of developing resistance, these can be given for a short time to persons who have been substantially exposed to anthrax [6].  The situations in which such exposure would occur include biological warfare and consumption of infected under-cooked meat.  Generally, an outbreak of anthrax may be controlled by eliminating the source of infection, disinfection, correct dispose of infected materials and vaccination of exposed domesticated animals.

WHO [6] recommends use of antibiotics with penicillin as a drug of choice for treatment of anthrax.  The other antibiotics that can be used in the treatment of anthrax are ciprofloxacin and doxycycline. In addition to the primary antibiotic (penicillin or ciprofloxacin), a supplementary antibiotic (clarithromycin, clindamycin, vancomycin, rifampicin, streptomycin, vancomycin or rifampicin) can be administered for severe cases.  Whilst the epidemiology of anthrax worldwide is well known, there is scanty information on the occurrence, its magnitude and factors associated with anthrax in Zambia.  The objective of the study was to review literature in order to tie up evidence on the epidemiology of anthrax in Zambia.

Methods

Zambia is a land locked country with three seasons: the rainy season (November to April), dry cool (May to August) and dry hot season (September to October/November).  In the dry seasons, animals will congregate around watering holes and graze on short grass, thereby, exposing to spores in the soil.  The disease is endemic in the Luangwa valley and Zambezi floodplain. The main source of the disease in the valley is game, while in the floodplain it is cattle [18].  Most livestock (cattle, goats and sheep) are found in Southern, Central, Lusaka, Copperbelt and Eastern provinces and mostly (83% of cattle, 64% of sheep and 97% of goats) reared by traditional farmers [19].

The Ministry of Health [20] adapted the WHO AFRO/CDC definitions for suspected and confirmed cases of anthrax as follows: A suspected case of anthrax is any person with acute onset of a disease characterized by several clinical forms of cutaneous form that is defined as any person with skin lesion evolving over 1 to 6 days from a popular through a vesicular stage, to a depressed black eschar invariably accompanied by oedema that may be mild to extensive; Any person with abdominal distress characterized by nausea, vomiting, anorexia and followed by fever is said to have gastro-intestinal form of anthrax; Any person suffering from Pulmonary (inhalation) form of anthrax has brief prodrome resembling acute viral respiratory illness, followed by rapid onset of hypoxia, dyspnoea and high temperature, with X-ray evidence of mediastinal widening; and any person with acute onset of high fever possibly with convulsions, loss of consciousness, meningeal signs and symptoms; commonly noted in all systemic infections, but may present without any other clinical symptoms of anthrax is said to have Meningeal anthrax.  Meanwhile, a confirmed case of anthrax is defined as a clinically compatible case of cutaneous, inhalational or gastrointestinal illness that is laboratory-confirmed by isolation or B. anthracis from an infected tissue or site; or other laboratory evidence of B. anthracis infection based on at least two supportive laboratory tests.

Literature was searched using google, google scholar and PubMed.  Literature not published in peer-reviewed journals as reports were obtained using google. Published works in peer-reviewed journals was gathered using google scholar and PubMed.

Results

A total of 7 publications were obtained using search words: anthrax, Zambia, epidemiology, outbreak and surveillance; and of these, 2 were full PubMed Central articles, 4 were abstracts without full articles and one was a citation. Animals reported to be affected in Zambia by anthrax include: cattle [21-23], hippopotamus, giraffe, buffalo, kudu, elephant, puku, wild dog, waterbuck, impala, wildebeest and hyena [24].

In Western province of Zambia, the overall cattle:human anthrax infection ratio was 1.47 between 1999 and 2007 in Western province of Zambia [23].  However, between 1991 and 1993, a ratio of 0.10 was observed [21].

Table 1. Cattle to human anthrax ratio in Western province of Zambia: 1991-1993 and 1999-2007

Table 1 shows the cattle:human anthrax infection ratios. A reduction of the human case fatality rate was observed in Zambia between 1990 and 2011 from 19.1% to 1.2% (Table 2; Siamudaala et al [22];Munang’andu et al. [23]; Hang’andu et al. [25]).  A similar observation was made between 1999 and 2007 in the upper Zambezi floodplain of western Zambia (Slope=-0.738, 95% CI [-1.394, -0.083]) as shown in Figure 1.

 Figure 1 Adapted from Munang’andu et al [22]

The common forms of human anthrax were cutaneous and gastrointestinal. Munang’andu et al [23] reported that human cases of the cutaneous form were higher than those for gastrointestinal in Western province.  Meanwhile, Siamudaala et al [21] found that gastrointestinal was more common than cutaneous in humans in Western and North-western provinces.  The signs and symptoms for cutaneous human anthrax cases were redness and oedema of the skin, oedema of the face, enlarged lymph nodes and fever.  Meanwhile the signs and symptoms for gastrointestinal human anthrax cases were vomiting, diarrhoea, abdominal pain and gastroenteritis [20,22].

Table 2 Cattle:Human ratio by year

Hang’ombe et al [24] reported that B. anthracis was susceptible to penicillin, chloramphenicol, doxycycline, tetracycline, streptomycin, ciprofloxacin, amoxicillin and gentamicin.  It was found to be resistant to vancomycin.  Meanwhile, it was intermediate susceptible to cotrimoxazole and erythromycin.

Discussion

Little has been published on both human and bovine anthrax in Zambia despite the frequent outbreaks and epidemics reported in the country.  Control of anthrax outbreaks and epidemic can only be effective if guided by results of research on the subject. Whilst control of anthrax in cattle through vaccination has a history of success in Zambia, it is practically impossible to control anthrax in game.  WHO [6] estimates that for a single carcass, there are 10 cutaneous and enteric human cases in Africa.  This high ratio may partly be attributed to hunger where people have to eat animals that died from anthrax [26,27].  Globally, WHO [8] estimates that there is one human cutaneous anthrax case to ten anthrax livestock carcasses. Although anthrax is a notifiable disease in Zambia, the observed numbers of human cases of anthrax in Western and North-western provinces are an underestimate partly due to inadequate disease surveillance and poor record keeping [28].

Cases of human anthrax cases maybe underreported because of fear of game rangers to suspect them to be poachers.  The other reason for underreporting of human cases maybe due to some nonspecific signs and symptoms of anthrax that may go unnoticed as cases of anthrax.  Alternatively, a timely and successful response to an outbreak would result in fewer infected humans in relation to infected cattle.  This would partly reflect a good cattle vaccination programme against anthrax.  Further, community’s acceptance of avoiding coming into contact with an infected animal by skinning, butchering or eating meat of such an animal would reduce human infection rate.

The change in the direction of the cattle:human anthrax ratio between 19911993 and 1999-2007 partly reflects changes in the control of the epidemic.

A reduction in the human case fatality rate indicates good case management.  An active surveillance of human cases of anthrax is recommended immediately there is an outbreak of anthrax in bovine so that people can start treatment as soon as possible in order to avoid severe cases of human anthrax. Although the common forms of human anthrax in Zambia are cutaneous and gastrointestinal, there are rare cases of inhalation anthrax.  People may be infected through the processing of hides and making of mats, drums or stools [23].   The most appropriate antibiotics to use to treat anthrax in Zambia include penicillin, chloramphenicol, doxycycline, tetracycline, streptomycin, ciprofloxacin, amoxicillin and gentamicin.  Although WHO [6] recommends use of vancomycin as a supplementary antibiotic in severe cases, it was found to be resistant to B. anthracis in Zambia [25].  Susceptibility tests are recommended to be conducted from time to time to monitor antibiotic resistance to B. anthracis.

Conclusion

Anthrax is endemic in Zambia but literature is scanty.  There is need for more research to inform policy.  A reduction in the human case fatality rate indicates good case management.  An active surveillance of human cases of anthrax is recommended immediately there is an outbreak of bovine anthrax in order for people to start treatment early and avoid severe forms of anthrax.

References

  1. Manchee RJ, Broster MG, Stagg AJ, Hibb SE. Formaldehyde solution effectively inactivates spores of Bacillus anthracis on the Scottish island of Gruinard. Appl Environ Microbiol 1994;60:4167–71.
  2. Wood JP, Meyer KM, Kelly TJ, Choi YW, Rogers JV, Riggs KB, et al. Environmental Persistence of Bacillus anthracis and Bacillus subtilis Spores. PLoS ONE 2015;10(9):e0138083.
  3. Wilson JB, Russell KE. Isolation of Bacillus anthracis from soil stored 60 years. J Bacteriol 1964;87:237–8.
  4. De Vos V. The ecology of anthrax in the Kruger National Park, South Africa. Salisbury Med Bull 1990;68S:19–23.
  5. Driks A. Overview: Development in bacteria: spore formation in Bacillus subtilis. Cell Mol Life Sci 2002;59:389-91.
  6. World Organisation for Animal Health, World Health Organization, Food and Agriculture Organization of the United Nations. Anthrax in humans and animals. 4th ed. Geneva: World Health Organization, 2008.
  7. Titball RW, Turnbull PC, Hutson RA. The monitoring and detection of Bacillus anthracis in the environment. Society for Applied Bacteriology Symposium Series 1991;20:9S–18S.
  8. World Health Organization. Guidelines for the surveillance and control of anthrax in humans and animals. 3rd ed. WHO/EMC/ZDI/98.6.
  9. CDC.  Anthrax: Basic Information. http://www.cdc.gov/anthrax/basics/index.html.
  10. CDC. Anthrax (Bacillus anthracis) 2010 Case Definition. URL: https://wwwn.cdc.gov/nndss/conditions/anthrax/casedefinition/2010/.
  11. Shadomy SV, Traxler RM, Marston CK.  Anthrax. In CDC. Infectious diseases related to travel. Chapter 3. URL: https://wwwnc.cdc.gov/travel/yellowbook/2016/infectiou s-diseases-related-to-travel/anthrax
  12. CDC. URL: http://www.cdc.gov/anthrax/basics/types/index.html.
  13. Clark CM. Anthrax – a real and present threat? Pharm J 1998;260: 374.
  14. Harrison LH, Ezzel JW, Abshire TG, Kidd S, Kaufmann Evaluation of ecological Tests for Diagnosis of Anthrax after an Outbreak of Cutaneous Anthrax in Paraguay. J Infect Dis 1989;160:706-10.
  15. Davies JCA. A Major Epidemic of Anthrax in Zimbabwe, Part II. Cent Afr J Med 1983;29:8-12.
  16. Ndyabahinduka DGK, Chu IH, Abdou AH, Gaifuba JK. An outbreak of Human Gastrointestinal Anthrax. Ann Ist Sanita 1984;20:205-8.
  17. Hambleton P, Carman JA, Melling J. Anthrax: the disease in relation to vaccines. Vaccine 1984;2:125-32.
  18. Zambezi Basin Wetlands Volume III: Land use change and human impacts. URL: http://www.zamsoc.org/wpcontent/uploads/2012/02/Wetlands-Phase-2-Vol-IIILand-Use.pdf.
  19. .Aregheore EM. Country pasture/forage resource profiles: Zambia II. Apia, Samoa, 2009. URL: http://www.fao.org/ag/agp/AGPC/doc/Counprof/zambia/ zambia2.htm.
  20. Ministry of Health [Zambia]. Technical guidelines for integrated disease surveillance and response in Zambia. Adapted from the 2010 2nd edition. Technical guidelines for integrated disease surveillance and response in the African region developed by WHO AFRO and CDC. Version 1.3. Lusaka, Zambia, Ministry of Health, 2011.
  21. Siamudaala VM, Bwalya JM, Munang’andu HM, Sinyangwe PG, Banda F, Mweene AS et al. Ecology and epidemiology of anthrax in cattle and humans in Zambia. Jpn J Vet Res 2006;54:15-23.

 

Facebooktwittergoogle_plusredditpinterestlinkedinmail