Ciprofloxacin Outperforms Cotrimoxazole and Doxycycline for cobatting Klebsiella pneumoniae Infections, Study Finds

According to the study, ciprofloxacin, a fluoroquinolone, demonstrated superior efficacy against non-ESBL and ESBL-producing Klebsiella pneumoniae strains. Results indicated that as the concentration of ciprofloxacin increased, its inhibitory effect became more pronounced, leading to significant bacterial cell death within a short period.

"Time-kill studies revealed that ciprofloxacin and doxycycline exhibited bactericidal activity, with ciprofloxacin demonstrating a stronger bactericidal effect than doxycycline. In contrast, cotrimoxazole displayed primarily bacteriostatic activity," the researchers wrote in Annals of Medicine and Surgery.

Antibiotic resistance is a major global issue, making it essential to optimize antibiotic use. Klebsiella pneumoniae is a Gram-negative bacterium responsible for various infections, including bacteremia, sepsis, urinary tract infections, pneumonia, and nosocomial infections. It can also produce Extended Spectrum Beta-Lactamase (ESBL). Ciprofloxacin, cotrimoxazole, and doxycycline are broad-spectrum antibiotics in the WHO's list of essential drugs.

Against the above background, Andy Setiawan, Study Program of Clinical Microbiology, Universitas Airlangga, Surabaya, Indonesia, and colleagues aimed to identify which of these antibiotics most effectively inhibited both non-ESBL and ESBL-producing strains of Klebsiella pneumoniae using a time-kill curve analysis.

For this purpose, the researchers used Klebsiella pneumoniae ATCC isolates, stored clinical isolates of non-ESBL and ESBL-producing strains, and a control group. The non-control isolates were treated with oral preparations of ciprofloxacin, cotrimoxazole, and doxycycline at concentrations of 1, 2, and 4 times the minimum inhibitory concentration (MIC) at intervals of 0, 2, 4, 6, 8, and 24 hours. The bacteria were cultured and incubated at each time point, and the number of colonies was counted.

The results were analyzed using time-kill curves and various statistical methods. Statistical analyses included ANOVA, post-hoc tests, Mann-Whitney, and Kruskal-Wallis tests.

The following were the key findings of the study:

• Ciprofloxacin, cotrimoxazole, and doxycycline demonstrated inhibitory effects on both non-ESBL and ESBL-producing Klebsiella pneumoniae.
• Ciprofloxacin exhibited the strongest inhibitory action.
• Statistically significant differences were observed between ciprofloxacin and cotrimoxazole at the 4- and 24-hour marks, as well as at 2 hours for concentrations of 1 MIC and 4 MIC.
• Differences between Klebsiella pneumoniae ESBL and Klebsiella pneumoniae ATCC were noted at the 8-hour time point.

The results indicate that ciprofloxacin is more effective at inhibiting the growth of K. pneumoniae non-ESBL, K. pneumoniae ESBL, and K. pneumoniae ATCC 13883 than cotrimoxazole and doxycycline.

"While all three antibiotics can inhibit these strains, the most notable difference in effectiveness is seen between ciprofloxacin and cotrimoxazole at concentrations of 1 MIC and 4 MIC, particularly for K. pneumoniae ESBL and K. pneumoniae ATCC 13883," the researchers concluded.

Reference:

Setiawan A, Widodo ADW, Endraswari PD. Comparison of ciprofloxacin, cotrimoxazole, and doxycycline on Klebsiella pneumoniae: Time-kill curve analysis. Ann Med Surg (Lond). 2022 Nov 5;84:104841. doi: 10.1016/j.amsu.2022.104841. PMID: 36536710; PMCID: PMC9758284.