Institut Pasteur de Bangui, BP 923, Bangui, Central African Republic
Keywords: UTIs, uropathogens, resistance
Sir,
Urinary tract infections (UTIs) are common bacterial infections encountered by both general practitioners and hospital doctors.1 In almost all cases, treatment must be initiated before the final bacteriological results are available. Therefore, studies to increase our knowledge about the types of pathogen responsible for UTIs and their resistance pattern to antibiotic drugs are very important to help clinicians choose the right empirical treatment.
The Central African Republic (CAR) is one of the poorest countries in the world and the general population can only afford generic drugs. Amoxicillin and trimethoprim/sulfamethoxazole are the major antibiotics used, but ciprofloxacin and gentamicin are also fairly cheap. No data concerning the antimicrobial resistance of bacteria isolated from UTIs in CAR have been published. To make it possible to advise physicians on the first line of treatment for UTIs in Bangui and to advise the health authorities about the antibiotics that should be available at low price in the CAR, we carried out a retrospective study on all of the bacterial strains isolated from the urine of outpatients who attended the Pasteur Institute of Bangui with a suspected UTI between January 2000 and April 2002.
All samples were collected at the Pasteur Institute of Bangui. Only patients who had pyuria and significant bacteriuria were included in the microbiological analysis. Only one specimen was included per patient.
The bacteria were identified by Grams stain and standard microbiological techniques.2 Susceptibility to antibiotics was assessed by the disc diffusion technique on MuellerHinton agar, as recommended by the Antibiogram Committee of the French Microbiology Society (ACFMS).3 After 24 h at 37°C, the zone of inhibition was measured. Antibiotic discs were obtained from Bio-Rad, Marne la Coquette, France. The antibiotics tested were recommended by the ACFMS.3 Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 were used as controls.
A descriptive analysis of data concerning the patients (age, sex, date of isolation) and all microbiological data was made using WHONET 5.0 software and Excel 2000.
Three hundred and thirteen pathogens were isolated from 307 patients. More than 84% of isolates were Enterobacteriaceae: E. coli (55.6%), Klebsiella pneumoniae (16.9%), Citrobacter diversus (4.2%), Salmonella spp. (3.5%), other Enterobacteriaceae (4.2%). Other Gram-negative bacteria (P. aeruginosa and Acinetobacter spp.) accounted for 3.5% of the isolates. Only 10.2% of the isolates were Gram-positive: S. aureus (4.5%), Streptococcus agalactiae (3.8%) and Enterococcus faecalis (0.6%).
Gram-positive cocci were susceptible to the major drugs used on these species. In contrast, a high percentage of the Enterobacteriaceae were resistant to amoxicillin and trimethoprim/sulfamethoxazole, although most remained susceptible to ciprofloxacin (Table 1).
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The main differences between our results and those obtained in developed countries were the resistance patterns of Enterobacteriaceae. A higher proportion of strains were resistant to amoxicillin and trimethoprim/sulfamethoxazole (80%) in our study than in developed countries. These results are similar to those observed in Sudan.5 This phenomenon can be explained easily. These antibiotics are the most commonly used in the CAR because they are cheap and easy to administer. The extensive use of these drugs explains the high selection pressure for resistant bacteria. Conversely, strains are rarely resistant to more expensive drugs.
As a result of cost, physicians rarely request bacteriological examinations of urine. This may explain the small number of strains isolated in our study. This phenomenon may have introduced bias into our study and may have led us to overestimate the prevalence of amoxicillin- and trimethoprim/sulfamethoxazole-resistant strains if a large number of patients attended the Pasteur Institute after the failure of empirical treatment. Since this information was not recorded, we cannot establish this. However, the resistance patterns were similar in the enteropathogenic bacteria isolated from stool samples (Pasteur Institute of Bangui, Annual Report, 2000), and therefore the rate of resistance observed in our study is probably realistic. This study shows the need for the development of new generic drugs, otherwise resistance to ciprofloxacin, the cheapest of the drugs that remain highly efficient, will increase rapidly in the near future.
To confirm these preliminary results, this retrospective study will be followed by a multicentre study on antimicrobial resistance in Bangui and many towns in the CAR.
Footnotes
* Correspondence address. Institut Pasteur de Bangui, Ambassade de France en RCA, 128 bis rue de lUniversité, 75351 Paris 07 SP, France. Tel: +236-61-28-37; Fax: +236-61-01-09; E-mail: atalarmin{at}yahoo.fr
References
1 . Sussman, M. (1998). Urinary tract infections. In Topley & Wilsons Microbiology and Microbial Infections, 9th edn (Collier, L., Balows, A. & Sussman, M., Eds), pp. 60121. Arnold, London, UK.
2 . Avril, J. L., Dabernat, H., Denis, F. & Monteil, H. (1988). Bactériologie Clinique. Ellipses, Paris, France.
3 . Comité de lAntibiogramme de la Société Française de Microbiologie. (2000). Communiqué 20002001. Société Française de Microbiologie, Paris, France.
4 . Chomarat, M. (2000). Resistance of bacteria in urinary tract infections. International Journal of Antimicrobial Agents 16, 4837.[CrossRef][ISI][Medline]
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Ahmed, A. A., Osman, H., Mansour, A. M., Musa, H. A., Ahmed, A. B., Karrar, Z. et al. (2000). Antimicrobial agent resistance in bacterial isolates from patients with diarrhea and urinary tract infection in Sudan. American Journal of Tropical Medicine and Hygiene 63, 25963.
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