Title : A comparative study on uroculturome antimicrobial susceptibility in apparently healthy and urinary tract infected humans
Abstract:
The uroculturome indicates the profile of culturable microbes inhabiting urinary tract infections (UTIs). UTIs are often caused by opportunistic pathogens and it is necessary to do urine culture to find an effective antimicrobial to treat UTIs. This study targeted to understand the profile of culturable pathogens in the urine of apparently healthy (128) humans and those with clinical UTIs (161). All the urine samples were analyzed for bacteria and fungi to quantify their numbers, their species and antimicrobial susceptibility following standard microbiological methods. In all cases of UTIs microbial counts were never less than 6000 (1.2×104 ± 2.32×103) colony-forming units (cfu)/ mL even from samples where more than one types of bacteria were detected, while in urine samples from apparently healthy humans count ranged from one to 3.33± 1.34×103/ mL. In eight samples (six from UTI cases and two from apparently healthy people) of urine, Candida (C. albicans 3, C. catenulata 1, C. krusei 1, C. tropicalis 1, C. parapsiplosis 1, C. gulliermondii 1) and Rhizopus species (1) were detected. Candida krusei was detected only in a single urine sample from a healthy person and C. albicans was detected both in urine of healthy and clinical UTI samples. In all the samples where fungal strains were detected also had one or more types of bacteria indicating bacterurea. Gram-positive bacteria were more commonly (OR, 1.98; CI99, 1.01-3.87) detected in urine samples of apparently healthy humans (96) than in samples from UTI cases (97). In contrast, Gram -ve bacteria were more common (OR, 2.74; CI99, 1.44-5.23) in urines of UTI cases (117) than in urine of apparently healthy humans. In urine samples, a total of 130 types of microbes were detected. Of the 161 samples from UTI cases, a total of 90 different types of microbes were detected and, 73 had only single type of bacteria while 49, 29, 3, 4, 1 samples had 2, 3, 4, 5, 6 and 7 types of bacteria, respectively. The most common bacteria detected as cause of UTI was Escherichia coli detected in 52 samples, in 20 cases as the sole cause of UTI, other 34 types of bacteria were detected as sole cause of UTI in 53 cases. In 128 urine samples of apparently healthy people, too, 89 different types of microbes were detected either singly or in association with others, from 64 urine samples only a single type of bacteria was detected while 34, 13, 3, 11, 2 and 1 sample yielded 2, 3, 4, 5, 6 and seven types of microbes, respectively. However, similar to urine from UTI cases in the urine of apparently healthy humans E. coli was the most common bacteria detected in pure culture from 10 samples followed by Staphylococcus haemolyticus (9), S. intermedius (5), and S. aureus (5), and similar types of bacteria also dominated in cases of mixed occurrence, E. coli was detected in 26, S. aureus in 22 and S. haemolyticus in 19 urine samples, respectively. A total of 41 species of microbes were exclusively detected in urine of UTI cases, and among them the most prominent was Alcaligenes faecalis (6), Acinetobacter indicus (4) and Streptococcus pyogenes (3), others were detected from one (34) or two (4) samples only. Similarly, 40 types of microbes were detected only from the urine of healthy people, the most common being Mammaliicoccus sciuri and S. cohnii ssp. urealyticus (3 samples each), others were detected from two (7) and one (27) samples respectively. Of the forty microbes detected only in the urine of apparently healthy subjects 28 were Gram +ve bacteria, 11 were Gram -ve bacteria (Aeromonas media, A. trota, Citrobacter amalonaticus, Escherichia vulneris, Hafnia alvei, Leclercia adecarboxylata, Providencia haemabachae, P. stuartii, Pseudomonas testosteronii, Roseomonas rosae and Xanthorhabdus poinarii). The bacteria detected only from the urine of healthy humans, do they have some health benefit or inhabit urinary tract commensally is an area of further investigation. Gram +ve bacteria isolated from urine samples' irrespective of health status were more often (p, <0.01) resistant than Gram -ve bacteria to ajowan oil, holy basil oil, cinnamaldehyde, and cinnamon oil, but more susceptible to sandalwood oil (p, <0.01). However, for antibiotics, Gram +ve were more often susceptible than Gram -ve bacteria to cefalosporins, doxycycline, and nitrofurantoin. On comparing antimicrobial susceptibility of Gram +ve bacteria isolated from urine samples of healthy humans and those suffering from UTI, bacteria from cases of UTI were more often (p, ≤ 0.01) resistant to lemongrass oil, carbapenems, cefalosporins, tetracycline, gentamicin, amikacin, cotrimoxazole, ciprofloxacin, chloramphenicol, and vancomycin but more susceptible to nitrofurantoin (p, <0.01). Gram -ve bacteria from urine of UTI cases was more often (p, ≤ 0.03) resistant than those from healthy humans to cinnamaldehyde, carvacrol, thyme oil, cinnamon oil, more often produced extended-spectrum β-lactamases, carbapenemases, and resisted cefalosporins, tetracycline, amikacin, gentamicin, cotrimoxazole, ciprofloxacin, chloramphenicol, amoxicillin, and colistin but were more often susceptible to lemongrass oil (p, <0.01). The results of the study and their implication in therapeutics of UTIs may be discussed in detail during the presentation.
