Surveillance of acute community acquired urinary tract bacterial infections

Potential Probiotics Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Co-Aggregate with Clinical Isolates of Proteus mirabilis and Prevent Biofilm Formation

A urinary tract infection (UTI) is a multi-factorial disease including cystitis, pyelonephritis, and pyelitis. After Escherichia coli, Proteus mirabilis is the most common UTI-associated opportunistic pathogen. Antibiotic resistance of bacteria and infection recurrence can be connected to biofilm formation by P. mirabilis. In this study, human and sheep isolates of P. mirabilis were investigated for antibiotic sensitivity using an antibiotic disk test. Co-aggregation of the tested potential probiotic bacilli, Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933, with the isolated pathogen was also evaluated. Then, the anti-biofilm activity of naturally derived metabolites, such as subtilin and subtilosin, in the bacilli-free supernatants was assessed against biofilms of P. mirabilis isolates. The isolated pathogens were sensitive to 30 μg of amikacin and 5 μg of ciprofloxacin but resistant to other tested antibiotics. After 24 h, auto-aggregation of B. amyloliquefaciens B-1895 was at 89.5% and higher than auto-aggregation of B. subtilis KATMIRA1933 (59.5%). B. amyloliquefaciens B-1895 strongly co-aggregated with P. mirabilis isolates from human UTIs. Cell-free supernatants of B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 showed higher antimicrobial activity against biofilms of P. mirabilis isolated from humans as compared with biofilms of sheep isolates. According to our knowledge, this is the first report evaluating the anti-biofilm activity of probiotic spore-forming bacilli against clinical and animal UTI isolates of P. mirabilis. Further studies are recommended to investigate the anti-biofilm activity and the mode of action for the antimicrobial substances produced by these bacilli, subtilosin and subtilin.

Susceptibility of Nitrofurantoin and Fosfomycin Against Outpatient Urinary Isolates of Multidrug-Resistant Enterococci over a Period of 10 Years from India

With the increasing emergence of drug resistance in enterococci, there have been very limited data on the efficacy of orally available nitrofurantoin and fosfomycin on enterococci causing urinary tract infections (UTIs), particularly for multidrug-resistant (MDR) strains. This study aimed to determine the in vitro effectiveness of these two drugs against the MDR enterococci. A total of 514 phenotypically and genotypically confirmed isolates of enterococci (239, 46.5% Enterococcus faecalis and 275, 53.5% Enterococcus faecium) showed E. faecalis as significantly more resistant (p < 0.05) to ciprofloxacin and high strength gentamicin. Vancomycin resistance was seen in 37 (7.2%) isolates. Of these, 114 (22.18%) isolates (51, 44.73% E. faecalis and 63, 55.26% E. faecium) were MDR. Nitrofurantoin minimum inhibitory concentrations (MICs) for the MDR enterococci varied from 1 to 128 μg/mL (MIC₅₀ 8 μg/mL, MIC₉₀ 64 μg/mL for E. faecalis), while fosfomycin MICs for the MDR E. faecalis, including vancomycin resistant enterococci (VRE) were in susceptible range (≤64 μg/mL, MIC₅₀ 8 μg/mL, MIC₉₀ 16 μg/mL). An efficacy ratio of ≥8 for nitrofurantoin was observed in the 39 (76.5%) MDR E. faecalis and 44 (69.8%) MDR E. faecium isolates as against the 50 (98%) E. faecalis isolates for fosfomycin. Although nitrofurantoin has been widely prescribed for the treatment of UTIs for the past several years, it was still found to be active in vitro against the urinary isolates of MDR enterococci, including VRE. As for fosfomycin, it holds robust potential to be used against the urinary MDR enterococci and VRE (E. faecalis).

Molecular identification and structural characterization of marine endophytic actinomycetes Nocardiopsis sp. GRG 2 (KT 235641) and its antibacterial efficacy against isolated ESBL producing bacteria

The present study was designed to identify the potential bioactive compound from endophytic actinomycetes (EA) Nocardiopsis sp. GRG 2 (KT 235641) against selected extended spectrum beta lactamase (ESBL) producing Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae). Initially, the multi drug resistance (MDR) effect of selected uropathogens was confirmed by respective UTI panel of Hexa antibiotics disc methods. The zone of inhibition ≤22 mm for ceftazidime, ≤ 27 mm for cefotaxime and ≤8 mm zone of MIC stripe against both the uropathogens of phenotypic methods confirmed, the selected strains were ESBL producer. Among the various EA extracts, GRG 2 extract showed excellent antibacterial activity against both ESBL producing P. aeruginosa and K. pneumonia by agar well diffution method. The molecular identification of selected GRG 2 strain was named as Nocardiopsis sp. GRG 2 (KT235641). The antibacterial metabolites present in the TLC elution was exhibited at 274 nm by UV visible spectrometer. The partial purification of preparative HPLC fraction 3 showed 14, 16 mm against P. aeruginosa and K. pneumoniae, respectively. Based on the antibacterial effect, the FT-IR, GC-MS and LC-MS analysis of fraction 3 was confirmed as 1, 4-diaza-2, 5-dioxo-3-isobutyl bicyclo[4.3.0]nonane (DDIBN). Further, the dose dependent inhibition of DDIBN against both ESBL producing pathogens was observed at 75 μg/mL by minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC). The increased cell death and disrupted cell membrane integrity were observed at MIC of DDIBN by confocal laser scanning electron microscope (CLSM) and scanning electron microscope (SEM). The results were proved that the DDIBN has potential antibacterial metabolites against ESBL producing pathogens and it can be applied for various other biomedical fields.

Surveillance of bacteria Pseudomonas aeruginosa and MRSA associated with chronic suppurative otitis media

INTRODUCTION

Suppurative otitis media is a critical disease causing perforation of the tympanic membrane associated with changes of the mucoperiosteum of the middle ear cleft.

OBJECTIVE

To isolate causative bacteria from chronic suppurative ear discharges and to ascertain their antibiotic profiles, of patients attending outpatients department in 3 years.

METHODS

For isolation of bacteria, samples of ear discharges were grown in suitable media and bacteria were subjected to antibiotic profiling by the Kirby-Bauer's method with presently used antibiotics.

RESULTS

A total of 1043 bacteria were isolated, including Pseudomonas aeruginosa and methicillin resistant Staphylococcus aureus, along with 121 fungal isolates. Among 371 P. aeruginosa isolates, tobramycin 30 had the highest susceptibility rate 93.2%, followed by ceftazidime 30, 91.5% and amikacin 10μg/disk 64.4%. Of 359 S. aureus isolates, there were 236 coagulase negative S. aureus+methicillin sensitive S. aureus isolates, while 123 isolates were methicillin resistant Staphylococcus aureus with 95.2% isolates susceptible to cloxacillin 15, 83.3% isolates to erythromycin 15 and 78.5% isolates to gentamicin 30μg/disk. Of 1164, 49 patients presented post aural abscess, 12 patients had intracranial complications, 9 patients had facial palsy and 3 patients had labyrinthitis. More than 90% P. aeruginosa and 90% S. aureus isolates were sensitive to tobramycin 30 and cloxacillin 30μg/disk, respectively.

CONCLUSION

Multidrug resistant strains of P. aeruginosa were more prevalent than those of S. aureus in ear discharges. Tobramycin and cloxacillin may be included in the formulatory antibiotic regimen to overcome bacterial infections in chronic suppurative otitis media.