ANTIMICROBIAL RESISTANCE PATTERN IN ESCHERICHIA COLI ISOLATED FROM CHILDREN ADMITTED AT SELECTED HEALTH CARE FACILITIES IN MOSHI MUNICIPALITY, TANZANIA

The emergence of antimicrobial resistance is a great challenge in preventing, controlling and treatment Gram-negative bacteria and has become a significant public health threat worldwide. The study aimed at determination of the prevalence and pattern of antimicrobial resistance in Escherichia coli isolated in children A descriptive cross sectional study was carried out on archived rectal swabs collected from 282 children aged 3 to 168 months admitted and in Rectal swabs were cultured on MacConkey agar media. The isolated Escherichia coli was identified and antimicrobial susceptibility test was done by using Kirby–Bauer disc diffusion method on Muller Hinton agar media.


Introduction
Antimicrobial resistance (AMR) development among Gram negative bacteria has become a significant public health threat worldwide. Currently there are fewer antimicrobials available for treatment and prevention of some of bacterial infections (1).Antimicrobial resistance development in some of bacterial strains undermines empirical treatment regimens, thereby limiting choice of appropriate antibiotic (2).As this problem continues to grow, epidemiological surveillance is warranted to generate data that is reliable to understand the distribution of AMR among healthcare settings and geographical regions (3).
AMR among Gram-negative bacteria poses a challenge in treating and controlling bacterial infectious diseases worldwide (4,5). The currently available information on the prevalence and patterns of AMR to different geographical regions has demonstrated that it is on rise (6, 7,8). The recommended and available antimicrobials have shown to be losing their ability to kill most of the infectious bacteria by developing resistance and becoming difficult to treat patients (9). Some bacteria pose ability to produce enzymes such as Extended Spectrum β-Lactamase (ESBL), which is responsible for the resistance to cephalosporin and penicillin (10).
The increase in circulating resistant strains of infectious bacteria make it difficult for the use of current available and recommended antimicrobial drugs (11).
Resistance of Gram negative bacteria to the recommended and available antimicrobial drugs is a growing public health problem in different locations worldwide leading to increased morbidity and mortality to patients (12).
Surveillance report has shown that 500 000 people suffer from antimicrobial resistance worldwide (13). The report on AMR in Africa revealed varying degree of AMR to the tested antimicrobials like amoxicillin 72.9%, trimethoprim/sulfamethoxazole 75%, gentamicin 22.1% and ceftriaxone 17.2% (14).
The study on AMR pattern at tertiary hospital in Tanzania showed that resistance of Klebsiella pneumoniae and Escherichia coli isolates to third generation cephalosporin were 38.5% and 29.3% respectively (15). Although AMR has been reported worldwide, there is limited information on Escherichia coli isolates in children admitted at health facilities in Moshi Municipality, Tanzania. Therefore, this study aimed to determine the Escherichia coli carriages and patterns of antibiotic resistance in children admitted at selected health facilities in Moshi Municipality, Tanzania.

Study design and setting
This was a descriptive cross-sectional facility-based study conducted in Moshi Regional Referral Hospital is located at the centre of Moshi Town, Mawenzi Regional Referral Hospital is a referral hospital for Kilimanjaro region and Pasua health centre which is a primary health care facility in Moshi municipality. All identified Escherichia coli isolates were included into the study.

Bacterial isolates
Archived rectal swabs collected from all enrolled children aged 3 to 168 months admitted at Kilimanjaro Medical Centre, Mawenzi Regional Referral hospital and Pasua Health Centre was cultured for bacterial growth at the teaching laboratory of Kilimanjaro KCMUCo in Moshi. Rectal swabs were first inoculated on MacConkey gar (MCA) plates and incubated at 37°C for 16 hours. Grown colonies were identified by using Kligler Iron Agar (KIA), Sulfide Indole and Motility (SIM), citrate utilization as well as Gram stain.
The zone of bacterial growth inhibition by the antibiotics was measured in millimeter (mm) according to Clinical Laboratory Standard Institute (CLSI) guideline of 2013. Escherichia coli ATCC 25922 was used as quality control strain. The following zone of inhibition was considered as resistant; ≤13mm for ampicillin and amoxicillin/clavunic acid, ≤12mm for gentamicin and chloramphenicol, ≤ 17mm for pipercillin-tazobactam and ceftazidime, ≤19mm for ceftriaxone and meropenem, ≤20mm for ciprofloxacin, ≤ 14mm for amikacin, ≤ 10mm for trimethoprim and ≤ 14mm for cefuroxime.

Detection of ESBL
All isolates resistant to cefuroxime were tested for ESBL production whereby ceftazidime was set 2cm away from amoxicillin/clavunic acid and synergism effect was determined. A test was considered as positive when a decreased susceptibility to ceftazidime was combined with a clear-cut enhancement of the inhibition zone of ceftazidime in front of amoxicillin/clavunic disc, often resulting in a characteristic shape-zone referred to as champagne-cork or keyhole (16).

Statistical analysis
Statistical Package for the Social Sciences (SPSS) version 20 was used for data analysis. Descriptive statistics were summarized by frequency and proportions. and cefuroxime 32.6% (Table 1) T   Among 245 non ESBL producers, high resistance was observed to ampicillin 198(80.8%) and trimethoprim 181(73.9%).All non ESBL producers were 100% sensitive to amikacin and meropenem (Table 3).

Discussion
All E. coli isolates that were analyzed demonstrated high rates of resistance to commonly used classes of antimicrobial. Similar observations have been reported by previous studies in Mwanza (9,15).
Escherichia coli showed a high rate of resistance to ampicillin. This high rate of resistance of E. coli to ampicillin could be contributed by its easy availability in the pharmacy at inexpensive prices affordable by everyone and is highly prescribed by clinicians since is a first line antibiotic as per National standard antibiotic guidelines (17) sometimes without doing culture and antimicrobial susceptibility testing leading to its overuse and misuse (18,19).
All Escherichia coli isolates were susceptible to amikacin and meropenem similar to previous reports (20,7,21). The low rates of resistance to amikacin and meropenem could be explained by the rare use of these antimicrobial since are second line according to National standard antibiotic guidelines (17) The prevalence of ESBL producing E. coli in this study was higher as compared to reports on globally isolated E. coli (21). However, it was lower as compared to the findings in hospitalized children in Dar es Salaam (22) and in Bahran (20) and Rwanda (23). The easily accessible and the habit of using third generation cephalosporin which is a broad spectrum without culture and antibiotic susceptibility testing may influence on the overuse of the drugs. AMR among ESBL producing bacteria to cephalosporin has been reported to be associated with over exposure to this class of drugs (24,25).
The high rate of antimicrobial resistance was observed to cephalosporins followed by penicillin, sulphonamide and fluoroquinolones among ESBL producing E. coli.
These are easily available and commonly prescribed by clinicians, hence creating the pressure of excessive antimicrobial use in Moshi. Similarly, a study in Mwanza, Tanzania reported an increase in the rate of AMR to third generation cephalosporins overtime among commonly prescribed antibiotics (9). The increases of pressure in antimicrobial use have been reported to promote development of AMR amongst different bacterial species and strains through horizontal gene transfer and thus contribute to the rapid dispersal in the community (10).