Comparative in-vitro evaluation of antibacterial activity of levofloxacin brands available in Pakistan



Comparative in-vitro evaluation of antibacterial activity of levofloxacin brands available in Pakistan

Sajid Bashir1, Syeda Rabia Nasir1, Faisal Usman2, Ibrahim Javed2*

Adv. life sci., vol. 2, no. 4, pp. 165-170, August 2015
*- Corresponding Author: Ibrahim Javed (Email:
Authors' Affiliations

[Date Received: 25/05/2015; Date Revised: 10/08/2015; Date Published Online: 25/08/2015]

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Supplementary Data


Background: Antimicrobial susceptibility against marketed antibiotic products is dynamic and changes with development of resistance in microbes. Susceptibility status of antibiotics helps health care practitioners in refining their prescribing trends and selection of suitable antibiotic and its commercial brand. Objective of this study was to evaluate the antimicrobial sensitivity and susceptibility patterns of levofloxacin of different national and multinational brands in Pakistan. Levofloxacin is among the commonly mis-prescribed antibiotic in Pakistan and this study will give an insight of microbial resistance/susceptibility status against quinolones and help prescribing practice. 

Methods: In this study 29 different brands of levofloxacin from different cities of Pakistan are evaluated for their sensitivity against four microbial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella Pneumonia. Evaluation was performed via disc diffusion method against standard drug discs.

Result: Different brands exhibited different antimicrobial status regardless of their price and national or multinational status. In low price range, Levomerc while Tavanic in high price range showed significant antimicrobial activity. Different brands are evaluated and compared statistically with price and activity as variant.

Conclusion: Antimicrobial activity of different brands of levofloxacin varied regardless of their national/multinational status and price factor. This study refined the suitability of different brands of levofloxacin against respective pathogens and disease indications.

Keywords: Levofloxacin, Brands, Infections, Resistance, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella Pneumonia  


Resistance against numerous antimicrobial drugs has become a serious threat in health care centers and hospitals. As per usage, an abrupt increase in resistance has been recorded for Quinolones from last few years [1-3]. Among quinolones, levofloxacin is a model drug and is commonly prescribed in many infections. So, it is always interesting for the practitioners to have an updated insight of antimicrobial resistance and susceptibility pattern of these frequently used antimicrobial drugs against common infections.

Developing countries, as in Asia, are more prone to infectious diseases either topically acquired via contagious and unhygienic contact with environment or from food i.e. food poisoning which leads to more frequent prescriptions of antibiotics [4, 5]. This is also associated with increased misuse of antibiotics leading to development of microbial resistance [6]. Levofloxacin is one of the most commonly prescribed antibiotic in developing countries, participating majorly in emergence of antibiotic resistance in Asia. It is commonly used as effective agent against food borne poisoning related to E. coli and Staphylococcus strains [7, 8].

Thus sensitivity pattern of different brands of levofloxacin is evaluated and compared with standard, against 4 different bacterial strains which are more likely and reported to acquire resistance against quinolones [9-11].


Twenty nine (29) different local and multinational brands of levofloxacin were collected from different cities of Pakistan (Lahore, Faisalabad and Sargodha) and used in this study (Table 1). Antibiotic sensitive levofloxacin discs (Oxoid CT 1615 B, USA) were used as standard. Bacterial strains i.e.  Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Escherichia coli (ATCC 8739), Klebsiella pneumonia (ATCC 700603) (Liofilchem, Italy) were used for susceptibility testing.

All required bacterial media i.e. Mueller Hinton Agar, Nutrient Agar, Broth and sample antibiotic discs were prepared according to standard laboratory protocols [12]. Briefly, sample tablets were dissolved in deionized and double distilled water. The solution was diluted to obtain the final concentration of 5 µg / 20 µl, which was pipetted on pre-sterilized, 6 mm Whattman filter paper discs. Bacterial inoculum of 0.5% McFarland standard solution was prepared by method reported in literature [13, 14]. Bacterial susceptibility testing was performed via disc diffusion method according to National Committee for Clinical Laboratory Standards (NCCL, M100-S12, 2002). Petri dishes containing Mueller Hinton Agar were inoculated with bacterial strains using a sterilized swab. Filter paper discs, impregnated with sample antibiotic (5 µg) and standard discs were placed and pressed in agar. These discs were incubated and zone of inhibition was measured in mm. One way ANOVA and Tukey test was applied to interpret the results.


The results of each levofloxacin products against S. aureus revealed that all brands gave satisfactory inhibition zones (Table S1). Levomer and Dynaquin had shown excellent zones of inhibition while Lazer, Levoday, Levocure, L-cyn, Levotasm, Voksec, Levo and Vizor gave the minimum zones. From the results of ANOVA F-test (Table S2) there was a statistical difference among the brands (P = 0.000). Results from Tukey comparison test (Table S3) revealed that there was significant difference among Levomerc, Levo, Levotas, Vizor, Voksec, L-cyn, Lazer, Levoday, Levocure, Dynaquin (P = 0.006).

In case of S. epidermidis, “Levomerc” (23 ± 0.3266 mm) gave excellent zone and “Bexus” (12 ± 0.8165 mm) gave minimum zone of inhibition that shows less effectiveness of “Bexus” as compared to rest of three bacteria (Table S1). The results of ANOVA F-test (Table S4) have shown that data was statistically significant (P = 0.000). Tukey comparison test (Table S5) indicated that activity of “Levomerc” was statistically different from “Levocure”, “Bexus”, “Lecin” (P = 0.00) and from “Levotas” (P = 0.001).

Most interestingly, remarkable zones of inhibition were seen with the “Levomerc” (41 ± 0.141 mm) and “Tavanic” (41 ± 0.408) against E. coli. “Bexus” (35 ± 0.326 mm) gave minimum zone of inhibition (Table S1). From the results of ANOVA F-test (Table S6), there was statistically significant difference among brands (P = 0.000). The zones of inhibition of brands against K. pneumonia indicated that “Levomerc” (32 ± 0 mm), “Cravit” (32 ± 0.04082), “Qumic” (32 ± 0.12472 mm), “Dynaquin” (32 ± 0.36742 mm) and “Tavanic” (32 ± 0.40825 mm) gave maximum zones and “Levocure” (25 ± 1.22474 mm) gave minimum zone of inhibition. Results were statistically significant (P = 0.000) as shown in ANOVA Table (Table S8). Results of Tukey test (Table S9) indicated that most of brands were statistically different from one another. “Levomerc” was statistically different from all brands except from “Spectrix” (P = 0.396), “Mclevo” (P = 0.969), “Lazer” (P = 0.999), “Tavanic”, “Qumic”, “Cravit” and “Dynaquin” (P = 1).

Figures and Tables

Figure 1 Figure 2 Table 1







Present study was conducted to evaluate the susceptibility of S. aureus, S. epidermidis, E. coli and K. pneumonia against 29 local and multinational brands of levofloxacin in Pakistan. Infections caused by these bacteria are more prevalent in developing countries of Asia. Usually, fluoroquinolones are mostly prescribed to cure these infections, so their chances to develop resistance are fairly high. Out of these 4 selected strains, S. aureusE. coli and K. pneumoniea are among the major strains investigated for food borne diseases [15]. Among major food sources in Pakistan, milk and poultry is found to be directly associated with Staphylococcal and Klebsiella based infections [16,17]. Disc diffusion method is employed in this study to perform anti-microbial activity of collected brands [18,19]. However, this method has reported to impart inaccuracies in results and somewhat results are not comparable across laboratories but in case of macrolide and quinolones i.e. ciprofloxacin and levofloxacin, this method is suitable and can be employed for initial susceptibility testing [20].

It was depicted in this study that the recorded efficacies of some brands of the levofloxacin sold in Pakistan, differ in their efficacies or potencies depending upon their brands or manufacturers. Some showed a higher efficacy and some showed lower efficacy when compared to the standard control. The differences in activities may be due to variations in the sources of raw materials (active and excipients), defective storage facilities and mishandling during distribution as described by previous reported studies [21,22]. Furthermore stability and storage conditions of the medications can also influence its therapeutic potency and this effect is more prominent when medication contain hydrophilic excipients and transported in humid and high temperature countries like Pakistan [23,24]. These differences in efficacies among available brands of antibiotic constitute a possible risk to health of patients. It was evaluated by various studies [25,26] that in developing countries, many manufactured drugs are implicated to be substandard. In developing countries the choice is influenced by manufacturer’s marketing strategies [22,27].

The different local and multinational brands of levofloxacin available in Pakistan showed effective but varying antibacterial activities against four selected susceptible organisms. As a whole “Levomerc” and “Dynaquin” have showed excellent efficacies with low price and their choice would be cost-effective while “Tavanic” and “Cravit” have shown comparatively less activity with high price but good activity in comparison to remaining brands. Levofloxacin is one of the most promising and commonly used newer quinolones that has broad spectrum of activity against both gram-positive and gram-negative organisms. The results of present study invite and give directions for evaluation of quinolones against other common disease causing microbes specifically in developing countries of Asia.

Conflict of Interest
Authors have no conflict of interest to declare.


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