Fluoroquinolone resistant bacterial isolates from the urinary tract among patients attending hospitals in Bushenyi District, Uganda

Introduction bacterial resistance to fluoroquinolones is on the rise globally, bacteria causing urinary tract infections (UTIs) are no exception to this fact. Judicious use of the current antibiotics by clinicians is therefore deemed necessary to combat development of resistance. This study determined fluoroquinolone resistant profiles, multiple antibiotic resistance indices (MARI), factors associated with fluoroquinolone resistance and their strength among patients attending hospitals in Bushenyi District, Uganda. Methods this was a cross-sectional study in which a total of 86 bacterial uropathogens isolated previously by standard microbiological methods were subjected to antibiotic susceptibility testing using Kirby Bauer disk diffusion method. Data for factors suspected to be associated with fluoroquinolone resistant UTI were obtained by use of questionnaires. Results the most resisted fluoroquinolone was ofloxacin with 29/83 (34.9%), followed by moxifloxacin 27/83 (32.5%), levofloxacin 24/86 (27.9%) and ciprofloxacin 23/86 (26.7%). The bacterial uropathogens that exhibited the highest frequency of fluoroquinolone resistant strains were P. mirabilis with 2/3 (66.7%) and E. faecalis with 2/3 (66.7%), followed by E. coli 19/36 (52.8%), S. aureus 13/27 (48.1%), K. oxytoca 2/6 (33.3%), K. pneumoniae 2/10 (20.0%) and P. vulgaris 0/1 (0.0%). All the bacterial uropathogens tested showed MARI of ≥ 0.2. Hospitalization, history of fluoroquinolones use in the last 12 months and wrong prescription of antibiotics were found to bear statistically significant relationships (p < 0.05) with fluoroquinolone resistant UTI. Conclusion antibiotic susceptibility testing of the first generation quinolones such as nalidixic acid in hospitalized patients, patients with history of fluoroquinolones' use in the last 12 months and wrong prescription of antibiotics should be adopted to avoid fluoroquinolone abuse. For empiric treatment of UTIs in Bushenyi District, ciprofloxacin still remains the first line of choice among the fluoroquinolone class of antibiotics.


Introduction
Urinary tract infections (UTIs) are known to be one of the commonest nosocomial and community-acquired bacterial infections [1]. Globally, about 150 million people per year are diagnosed with UTIs, resulting into more than 6 billion US dollars used for health care [2][3][4]. The World Health Organization (WHO) surveillance report on antimicrobial resistance in 2014 indicated that, nine bacteria of global concern are the main cause of nosocomial and community-acquired infections [5].
Complicated UTI, such as pyelonephritis is most frequently treated with fluoroquinolones [6], although ciprofloxacin is commonly used in the treatment of uncomplicated UTIs [7]. The rapid increase in the use of fluoroquinolones has led to the emergence of ciprofloxacin resistant bacterial uropathogens globally, for uncomplicated UTIs it ranges from 2% to 69% and goes up to 98% for complicated UTIs [8].
While in an out-patient population with UTIs in the US, ciprofloxacin resistance of 17.1% was observed [10]. In an outpatients department in the Netherlands, a much lower resistance to ciprofloxacin of ∼10% was reported in 2014 [11]. Although a slightly higher resistance of 12% was reported in a study that included both in-patients and outpatients with complicated UTIs in 2004-09 [12]. Fluoroquinolones are among the most frequently prescribed antibiotics in the empirical treatment of UTIs [13]. There is increasing resistance in recent years especially among Gram negative bacteria due to over-prescription of fluoroquinolones [14]. The rates of bacterial resistance to fluoroquinolones varies world over, ranging from greater than 50% community acquired uncomplicated UTI to extremely higher value of 98% for strains responsible for complicated community-acquired UTI.
In nosocomial UTI, bacterial uropathogens are more resistant to fluoroquinolones than community-acquired UTI [ resistance was reported in a study carried out to determine the factors associated with community-acquired urinary tract infections among adults attending assessment centre, Mulago hospital Uganda [24]. In Bushenyi District of Uganda, in a study to determine the prevalence and antibiotic susceptibility pattern of bacterial urinary tract infections among suspected diabetic patients attending clinics, a resistance of 36/103 (35.0%) to ciprofloxacin was reported [25]. Empirical treatment of bacterial infections depends on the selection of the most appropriate antibiotics, depending upon regional susceptibility profile, key indicators in the genomic evolutionary trend and efficacy of the antibiotic commonly prescribed in a specific locality [4] [26].
Antibiotic susceptibility testing: the antibiotic susceptibility was done at Mbarara University of Science and Technology-Teaching Hospital (MUST-TH) microbiology laboratory. Antibiotic susceptibility was performed on bacterial isolates from midstream urine (MSU) using antibiotic discs, according to clinical and laboratory standards institute (CLSI) [27] on Muller Hinton agar. The prepared media was inoculated with bacterial suspension equivalent to 0.5 MacFarland turbidity. The commercially available antibiotic discs containing the following antibiotics: nalidixic acid (30μg), ciprofloxacin (5μg), ofloxacin (5μg), levofloxacin (5μg), moxifloxacin (5μg) (Himedia, India) was aseptically placed on the surfaces of the sensitivity agar plates with a sterile forceps and allowed to stand for 30 mins. The plates were then incubated for 18-24 hrs at 37 º C. Zones of inhibition after incubation was observed, noted and interpreted according to CLSI [27]. Isolates showing intermediate antibiotic susceptibility were considered to be resistant. Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) were used as quality control organisms for the antimicrobial susceptibility testing according to CLSI [27]. K. oxytoca 2/6 (33.3%), K. pneumoniae 2/10 (20.0%) and P. vulgaris 0/1 (0.0%) ( Table 2). All the bacterial uropathogens tested showed MARI of ≥0.2 ( Table 3).  (Table 4, Table 5).

Discussion
This study determined the fluoroquinolone resistance profiles, MARI, factors associated with fluoroquinolone resistance and their strength to the commonly encountered uropathogens among patients attending hospitals in Bushenyi District, Uganda. Data from this study provides an important platform for comparing and monitoring the level of antimicrobial resistance among bacterial uropathogens to guide policy and clinicians on the selection of the most appropriate drugs for managing UTIs. There are reports of increasing antimicrobial resistance globally [30][31][32] index is a tool used to assess the spread of bacterial resistance in a specified population [42,43].
Values of MARI ≥0.2 indicates that bacterial strains of this nature originate from an ecological system where multiple antibiotics are being used or abused [44][45][46]. This is a clear indication that a huge proportion of these bacterial uropathogens were exposed to multiple antibiotics and this, resulted into development of resistance to these drugs. Similar incidences of resistance, though to different sets of antibiotics have been reported elsewhere [28,44]. Furthermore, reports of resistance of bacterial uropathogens to commonly used antibiotics have been documented [35].

Competing interests
The authors declare no competing interests.

Authors' contributions
This research was carried out in collaboration with all authors. Martin

Acknowledgments
The authors are thankful to the hospital administrators of KIU-TH, Ishaka Adventist Hospital and Comboni Hospital Kyamuhunga for granting them the opportunity to collect the samples at their facilities.
They are also grateful to the physicians, laboratory technologists and nurses of the same hospitals for their guidance and support that allowed this research work to be a success. This work was funded by Kampala International University staff development research funds. Table 1: resistance profiles of the bacterial uropathogens to fluoroquinolones