E Donkor, E Nartey
ghana, gram negative rods, multiple drug resistance, streptococci
E Donkor, E Nartey. Nasal colonisation of drug resistant bacteria in Ghanaian children less than five years. The Internet Journal of Microbiology. 2007 Volume 5 Number 2.
Bacteria isolated from nasal specimens collected from 100 subjects less than 5 years, were identified and their susceptibility characterised by standard microbiological methods. The organisms isolated from the subjects and prevalence rates were as follows:
Antibiotic-resistant organisms lead to increased hospitalizations, health costs, and mortality. Antimicrobial drug resistance has therefore become an important public health concern associated with serious consequences for the treatment of infections (1,2). The phenomenon has been attributed to the misuse of antimicrobial drugs which provide selective pressure favouring the emergence of resistant strains. One of the major interventional strategies for containing the problem of antimicrobial resistance includes effective surveillance of resistance among common pathogens such as
Drug resistance is a global problem, however, it tends to carry more significance in the developing world, where treatment options are limited and lack of resources constrain implementation of surveillance. In Ghana, the incidence of bacterial resistance is known to be very high (6), probably due to the poor enforcement of drug policies on antibiotic usage. At present, information available on bacterial resistance in the country is inadequate, and is mainly related to clinical isolates, while very little is known about resistance of normal flora. Antimicrobial therapy in Ghana is empirical in majority of cases, and surveillance data on resistance from clinical and normal flora isolates is urgently needed for effective treatment.
The aim of this study was to assess the nasal carriage of drug resistant bacteria in children less than five years, and the possible relationship with age and sex.
Materials and Methods
This prospective study was carried out at the Child Health Department of the Korle-Bu Teaching Hospital (KBTH) in 2006. This hospital is the largest hospital in Ghana and serves as a referral center with about 1600 beds (7). It is also one of the largest and most well equipped teaching hospital in West Africa. Subjects for this study were both male and female children aged less than 5 years visiting the Out Patient Department of the hospital. A sample size of 100 was chosen based on 95% confidence limit with an allowable error of 10%. All children aged less than five years attending the hospital during the study period were eligible for inclusion in the study, while those who had taken antibiotics two weeks to reporting to the hospital were generally excluded. After ethical clearance and informed consent from the mothers of the study subjects, nasal swabs were taken with sterile cotton tipped swab sticks. A structured questionnaire was used to gather data on vital statistics and whether or not their wards had been given antibiotics in the last 2 weeks.
Specimens were immediately inoculated into Brain-Heart Infusion broth and transported to the laboratory. After overnight incubation at 37oC, they were inoculated on Blood Agar (BA), Chocolate Agar (CA) and MacConkey agar for isolation and identification of organisms. The inoculated plates were incubated at 37oC for 18 to 24 hours and re-incubated for 48 hours when no bacterial growth was noted after 18 hours incubation. CA plates were incubated at 37oC in 5% carbon-dioxide overnight (18-24 hours). Colonial morphology of organisms were noted and confirmed with Gram Staining of slides. Isolates were identified by standard biochemical methods (8). Analytical profile index (API) was used to confirm a number of the identified organisms. The Kirby Bauer method (9) of sensitivity testing was employed to determine the antibiogram of the isolates using the following antimicrobial drugs with their disk content in microgram (ug):- ampicillin (10), tetracycline (30), cotrimoxazole (25), gentamicin (30), cefuroxime (30), cefotaxime (30), penicillin (10), erythromycin (15), cloxacillin (5), and, all commonly used in Ghana.
Organisms isolated from the study subjects included a wide range of bacteria as shown in Table 1. The most prevalent organism was
The prevalence of multiple drug resistance in
The nasal specimens yielded a wide range of bacterial agents with
Carriage rates of 17.9%, 18.7%, and 28.4% have also been reported in children in other parts of the world (17,18,19).
There was no significant association of nasal bacterial colonisation with age and sex, though some previous reports had shown this relationship for age (20). The absence of this observation in the study may be due to the small age range of less than five years used.
Resistance of normal flora is of concern, and in this study, the prevalence of multiple drug resistance of nasal flora
High levels of resistance were observed for penicillin, ampicillin, and cotrimoxazole. These are drugs which had been reported as having high percentage resistance for a lot of microorganisms for several years, and the rate of resistance had been rising over the years not only for clinical isolates but also for the normal intestinal flora of the healthy population (23,24). Lower prevalence rates of resistance were observed for gentamicin, cloxacillin, erythromycin and cefotaxime. Relatively these drugs have been on the Ghanaian market for a relatively short period of time as compared to drugs like ampicillin, and therefore may not have been subjected to high use and or misuse. In addition, some of these drugs are expensive and may be prescribed for serious infections, thus limiting their usage.
Extremely high resistance rates were observed for
Susceptibility tests were not carried out on coagulase negative
The study has shown that the nasal area of the children habour various multiply resistant bacteria. This is of public health concern, given the fact that bacterial normal flora could transmit drug resistance to pathogens, and could also cause infections in people with lowered immunity such as infants who formed the subjects in this study.
The technical support provided by the entire staff of the Department of Microbiology, University of Ghana Medical School is gratefully acknowledged.