Development Of Antibiotic-resistant Bacteria Research Articles

Environmental Health Risks of Antibiotic Residue in Sewage Discharged from Mosul City: An ELISA-Based Investigation

This study aimed to showed that all sixteen samples collected from different areas of the city had detectable levels of antibiotic residues, with a mean concentration of 4.1 ng/ml and a standard deviation of 0.656 ng/ml. These findings indicate that antibiotics are being overused or not disposed of properly in the area, posing a potential risk to environmental health. The ELISA technique was effective in creating a standard curve for determining the antibiotic concentration in unknown samples. The standard curve showed a linear relationship between the concentration of antibiotics and the absorbance values obtained from the ELISA assay. By comparing the mean concentrations of antibiotic residues between different areas of the city, significant differences were found. For example, the left side of the city had a mean concentration of 3.97 ng/ml, while the right side of the city had a mean concentration of 4.19 ng/ml. The difference in the mean concentrations between the two areas was statistically significant (p<0.05). The high mean concentration of antibiotic residues detected in the samples suggests that antibiotics are being overused or not properly disposed of in the area. In conclusion, this study shows that there are detectable levels of antibiotic residues in the discharged water of Mosul City, indicating a potential threat to environmental health. Implementing measures to reduce the use and ensure proper disposal of antibiotics can help mitigate the potential risks associated with the development of antibiotic-resistant bacteria, protecting public health and environmental well-being.

Near-Infrared-Induced NO-Releasing Photothermal Adhesive Hydrogel with Enhanced Antibacterial Properties.

Bacterial infection and the development of antibiotic-resistant bacteria have decreased the effectiveness of traditional antibiotic treatments for wound healing. The design of a multifunctional adhesive hydrogel with antibacterial activity, self-healing properties, and on-demand removability to promote wound healing is highly desirable. In this work, a photothermal cyclodextrin with a NO-releasing moiety has been incorporated within an oxidized sodium alginate conjugated polyacrylamide (OS@PA) hydrogel to get a photothermal NO-releasing GSNOCD-OS@PA hydrogel. Such a multifunctional hydrogel has the unique feature of combined antibacterial activity as a result of a controlled photothermal effect and NO gas release under an 808 near-infrared laser. Because of oxidized sodium alginate (OSA), the hydrogel matrix easily adheres to the skin under twisted and bent states. In vitro cytotoxicity analysis against 3T3 cells showed that the hydrogels OS@PA and GSNOCD-OS@PA are noncytotoxic under laser exposure. The temperature-induced NO release by GSNOCD-OS@PA reached 31.7 mg/L when irradiated with an 808 nm laser for 10 min. The combined photothermal therapy and NO release from GSNOCD-OS@PA effectively reduced viability of both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) to 3 and 5%, respectively. Importantly, the phototherapeutic NO-releasing platform displayed effective fibroblast proliferation in a cell scratch assay.

Resistant Bacteria in Broiler Litter Used as Ruminant Feed: Effect of Biotic Treatment.

The use of antimicrobial drugs and coccidiostats in poultry farming is widespread, with a significant proportion of these drugs being excreted and released into the environment. The residues of such drugs in poultry litter (PL) can result in the development of antibiotic-resistant bacteria. The impact of different biotic treatments (aerobic, anaerobic, and stacking) on broiler litter (BL) before its use as animal feed has not been studied extensively, nor have the differences between antimicrobial-dependent and independent broiler farms been investigated. This study aimed to determine the resistant bacteria in BL used as ruminant feed before and after litter treatment. The results show that the most resistant bacteria before BL treatment were the Enterococcus species. This study also found that the quantity of amoxicillin-resistant Enterococcus detected in samples from antimicrobial-dependent farms was significantly higher than in those from antimicrobial-independent farms. Additionally, 14% of bacteria were multi-resistant to tetracycline, sulfafurazole, and erythromycin in antimicrobial-independent farm litters, significantly lower than those measured in antimicrobial-dependent broiler farm litter. This study highlights the importance of better understanding, regulating, managing, and using animal waste appropriately to reduce the number of antibiotic-resistant bacteria and minimize the use of antimicrobials that carry high risks for animals, humans, and the environment.

A Review of Antibiotics, Antibiotic Resistant Bacteria, and Resistance Genes in Aquaculture: Occurrence, Contamination, and Transmission.

Antibiotics are commonly used to prevent and control diseases in aquaculture. However, long-term/overuse of antibiotics not only leaves residues but results in the development of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). Antibiotics, ARB, and ARGs are widespread in aquaculture ecosystems. However, their impacts and interaction mechanisms in biotic and abiotic media remain to be clarified. In this paper, we summarized the detection methods, present status, and transfer mechanisms of antibiotics, ARB, and ARGs in water, sediment, and aquaculture organisms. Currently, the dominant methods of detecting antibiotics, ARB, and ARGs are UPLC-MS/MS, 16S rRNA sequencing, and metagenomics, respectively. Tetracyclines, macrolides, fluoroquinolones, and sulfonamides are most frequently detected in aquaculture. Generally, antibiotic concentrations and ARG abundance in sediment are much higher than those in water. Yet, no obvious patterns in the category of antibiotics or ARB are present in organisms or the environment. The key mechanisms of resistance to antibiotics in bacteria include reducing the cell membrane permeability, enhancing antibiotic efflux, and structural changes in antibiotic target proteins. Moreover, horizontal transfer is a major pathway for ARGs transfer, including conjugation, transformation, transduction, and vesiculation. Identifying, quantifying, and summarizing the interactions and transmission mechanisms of antibiotics, ARGs, and ARB would provide useful information for future disease diagnosis and scientific management in aquaculture.

Public health issues related to poultry and poultry products

Several factors are influencing the poultry production and health such as strong global competition; changes in social, political and consumer perceptions with regard to food safety, animal welfare and environmental protection.&#x0D; The loss of consumer confidence and trust in the quality and safety of poultry meat and poultry products will remain a continuous major challenge. Many human foodborne infections are linked to poultry. Control and/or elimination of these organisms present a great challenge.&#x0D; The development of antibiotic resistant bacteria will also be a continuous public health hazard. The future concept of animal health will cover not only the absence of disease in birds, but also the relationship between the health of animals and their welfare. It will also take into account social, economic and ethical considerations, as well as support the achievement of a high level of environmental protection. In general, consumer expectations for high quality products will strongly influence future production methods. This means that farmers, veterinarians, stockholders and all other partners involved in the production chain need to share more responsibilities. The present paper explores these points.

Synthesis and Characterization of Nitric Oxide-Releasing Ampicillin as a Potential Strategy for Combatting Bacterial Biofilm Formation

Biofilm formation on biomaterial interfaces and the development of antibiotic-resistant bacteria have decreased the effectiveness of traditional antibiotic treatment of infections. In this project, ampicillin, a commonly used antibiotic, was conjugated with S-nitroso-N-acetylpenicillamine (SNAP), an S-nitrosothiol compound (RSNO) used for controlled nitric oxide (NO) release. This novel multifunctional molecule is the first of its kind to provide combined antibiotic and NO treatment of infectious pathogens. Characterization of the molecule included NMR, FTIR, and mass spectrometry. NO release behavior was also measured and compared to pure, unmodified SNAP. When evaluating the antimicrobial efficacy, the synthesized SNAPicillin molecule showed the lowest MIC value against Gram-negative Pseudomonas aeruginosa and Gram-positive methicillin-resistant Staphylococcus aureus compared to ampicillin and SNAP alone. SNAPicillin also displayed enhanced biofilm dispersal and killing of both bacterial strains when treating a 48 h biofilm preformed on a polymer surface. The antibacterial results combined with the biocompatibility of the molecule show great promise for infection prevention and treatment of polymeric interfaces to reduce medical device-related infections.

Treatment of hospital wastewater: emphasis on ecotoxicity and antibiotic resistance genes

AbstractBACKGROUNDHospital wastewater (HWW) charges wastewater treatment plants (WWTPs) with a mixture of contaminants such as pharmaceutically active compounds (PhACs) and pathogenic bacteria. This matrix is considered highly toxic to the ecosystem and organisms, and it may induce the development of antibiotic resistant bacteria (ARB) and the transfer of antibiotic resistance genes (ARGs) within microbial communities. Conventional WWTPs cannot treat HWW effectively, because they have not been designed to confront this challenge. Therefore, this study investigated the applicability of photocatalysis to purify HWW, regarding its ecotoxicity and the removal rates of targeted substances, selected pathogenic bacteria and specific ARGs.RESULTSThe HWW samples showed high toxicity towards the bioindicator Daphnia magna population, while they also contained significant levels of ARB and ARGs. Upon application of the photocatalytic treatment, the pharmaceutical concentrations decreased at a rate of &gt;80% and the removal rates of the examined bacteria (Escherichia coli, Enterococci, Klebsiella sp. and Staphylococcus sp.) were &gt;80%. Importantly, the bacteria remaining after photocatalysis were sensitive to the tested antibiotics. Conversely, the examined ARGs were present in high concentrations before and after photocatalytic treatment. For example, the concentrations of the selected genes, namely ampC, sul2, tetA and qnrA, in the effluents were from 104 to 106 gene copies L−1.CONCLUSIONSPhotocatalysis may be a promising treatment technique for the elimination of PhACs and pathogenic bacteria from HWW. Moreover, it proved capable of altering the antibiotic resistance profile of the bacteria surviving after treatment, making them sensitive to certain antibiotic compounds. However, the main concern regarding public health protection remains, as the presence of ARGs in effluents in considerable concentrations may induce antibiotic resistance in bacterial communities of aquatic environments. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Wide-Scope Target and Suspect Screening of Antibiotics in Effluent Wastewater from Wastewater Treatment Plants in Europe.

The occurrence of antibiotics in the environment could result in the development of antibiotic-resistant bacteria, which could result in a public health crisis. The occurrence of 676 antibiotics and the main transformation products (TPs) was investigated in the 48 wastewater treatment plants (WWTPs) from 11 countries (Germany, Romania, Serbia, Croatia, Slovenia, Hungary, Slovakia, Czechia, Austria, Cyprus, and Greece) by target and suspect screening. Target screening involved the investigation of antibiotics with reference standards (40 antibiotics). Suspect screening covered 676 antibiotics retrieved from the NORMAN Substance Database (antibiotic list on NORMAN network). Forty-seven antibiotics were detected in effluent wastewater samples: thirty-two by target screening and fifteen additional ones by suspect screening. An ecotoxicological risk assessment was performed based on occurrence data and predicted no effect concentration (PNEC), which involved the derivation of frequency of appearance (FoA), frequency of PNEC exceedance (FoE), and extent of PNEC exceedance (EoE). Azithromycin, erythromycin, clarithromycin, ofloxacin, and ciprofloxacin were prioritized as the calculated risk score was above 1. The median of antibiotics' load to freshwater ecosystems was 0.59 g/day/WWTP. The detection of antibiotics across countries indicates the presence of antibiotics in the ecosystems of Europe, which may trigger unwanted responses from the ecosystem, including antibiotic resistance.

Synergistic effect of honey in combination with silver nanoparticles on isolated pathogens from urinary tract infection

Background Urinary tract infections (UTIs) are the most prevalent bacterial infections, affecting 150 million people worldwide each year. UTIs can be caused by a variety of pathogens, but Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Proteus mirabilis are the most frequent culprits. The growth and development of antibiotic-resistant bacteria are currently a major worry for the international health community. Looking for a treatment substitute could be effective in tackling this issue. The honey has a low pH (mean 4.4) value, which makes it unfavorable for bacterial growth; undiluted honey combination with silver nanoparticles (AgNPs) shows synergistic antimicrobial effect and helps lessen infection.Aim This study was undertaken to find out the effectiveness of honey containing AgNPs in the antibacterial activity of isolated urine pathogens.Patients and methods A total of 30 patients with UTI were included through purposive sampling technique, and urine samples were collected from them. A semiquantitative approach was used to cultivate specimens of urine on MacConkey agar and blood agar. After 24 h of incubation, bacterial growth was seen on the plates. Then, colonies were counted and the number of microorganisms per milliliter in the original material was calculated by multiplying the number of CFUs by 1000.Results A total of 10 bacterial isolates were found in the 30 urine samples, and biochemical studies showed that these isolates were from three different species. The most common strain of E. coli represented 82%, followed by P. aeruginosa (12%) and P. mirabilis (6%). In all three organisms examined with undiluted honey mixed with AgNPs, the zone of inhibition was more pronounced when compared with only honey, AgNPs, and diluted honey mixed with AgNPs.Conclusion The results of the current investigation showed that multifloral honey combined with AgNPs was effective against urinary infections.

Dentistry with antibiotic prophylaxis

Prophylactic antibiotics are being used before dental treatment especially to prevent IE (infective endocarditis) has been reduced which contributes to decreased unnecessary use of antibiotics and over development of antibiotic resistant bacteria since 20 years. Medically compromised patients with history of prior prosthetic joint complications, both advanced/congenital cardiac problems or immunologically compromised with chronic disease like uncontrolled diabetes, antibiotic prophylaxis is still recommended.

A high-capacity malleable cellulose aerogel with layered double hydroxide decorating ZIF-8 for efficient adsorption of ciprofloxacin

The misuse of ciprofloxacin (CIP) poses significant risks to our ecosystems by causing serious environmental pollution and the development of antibiotic-resistant bacteria, which requires effective remediation technologies. Herein, we developed a composite material (CMC/CoNiFe-LDH/ZIF-8, abbreviated as CLZ) of loading layered double hydroxide (CoNiFe-LDH) decorating zeolitic imidazolate framework (ZIF-8) on the carboxymethylcellulose sodium (CMC) aerogel as an adsorbent for CIP removal. The CMC aerogel in the composite provided a porous structure as the growth template of CoNiFe-LDH, while CoNiFe-LDH provided growing points for ZIF-8, and ZIF-8 could be used as a carrier for loading CIP, resulting in a high adsorption property of CLZ with optimized mass ratios of CMC/CoNiFe-LDH aerogels and ZIF-8 at 5:1 (denoted as CLZ-1). The adsorption process of CLZ-1 followed the pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum capacity of CLZ-1 to adsorb CIP was 1397.5 mg·g−1. The results of characterization, data fitting and parameter revealed that strong hydrogen bonding, complexation of unsaturated metals, electrostatic interaction, and π–π stacking between CLZ-1 and CIP were the main mechanisms for CIP adsorption. In addition, the CLZ-1 was successfully used as a solid phase extraction material combined with high performance liquid chromatography (HPLC) for the detection of CIP. Meanwhile, the CLZ-1 adsorbed CIP showed excellent antibacterial activity. Hence, CLZ-1 demonstrated great potential and promising practicability in separation and removal of antibiotic contaminants.

Single-step antibiotic-mediated synthesis of kanamycin-conjugated gold nanoparticles for broad-spectrum antibacterial applications.

Widespread and irrational use of antibiotics results in the development of antibiotic-resistant bacteria. Thus, there is a need to develop novel antibacterial agents in order to replace conventional antibiotics and to increase the efficacy of already existing antibiotics by combining them with other materials. Herein, a single-step antibiotic-mediated synthesis of antibiotic-conjugated gold nanoparticles is reported. In this single-step method antibiotic Kanamycin, an aminoglycoside itself plays the role of reducing as well as capping agent by reducing gold salt into gold nanoparticles. The kanamycin-conjugated gold nanoparticles (Kan-AuNPs) were confirmed by UV-Visible spectroscopy and further physico-chemically characterized by various instrumental techniques. Synthesized Kan-AuNPs showed broad-spectrum antibacterial activity against Gram-positive Staphylococcus aureus as well as Gram-negative Escherichia coli bacterial strains. They are also found to be effective against Pseudomonas aeruginosa and pathogenic E.coli isolated from urinary tract infections (UTIs) patients, which are responsible to cause hospital-acquired infections like nosocomial, burn wound and UTIs. The minimum inhibitory concentration (MIC) of Kan-AuNPs is 50 μg ml-1 for S. aureus and E.coli, 125 μg ml-1 for P.aeruginosa and 100 μg ml-1 for E.coli isolated from UTIs patients. It is also evident that the MIC of Kan-AuNPs for antibacterial activity is lower as compared to antibiotic kanamycin alone for all bacterial strains. Hence, the one-step strategy of synthesis for Kan-AuNPs is a suitable strategy for fighting infectious bacterial strains in hospitals, healthcare and the pharmaceutical industry.

Multidrug resistance and class 1 integron presence in Escherichia coli isolates from a polluted drainage ditch’s water

ABSTRACT The impact of contamination of water drainage ditches in the development of antibiotic-resistant bacteria has been scarcely studied in Mexico. In this regard, 101 isolates of E. coli were obtained from water samples from a ditch in Sinaloa, during one year. The antimicrobial resistant profiles, the presence of the class 1 integron and evolutionary relationship of intI1 sequences were determined. The 47.5% of strains were resistant and 5.9% multidrug resistant (MDR) with an average multiple antibiotic resistance index value of 0.45. The highest resistance was registered with β-lactam (39.6%) and quinolone (9.9%). The intI1 gene was detected in 11.9% of the isolates, and no association with MDR was found. Sequence were associated with human and animal host isolates. MDR E. coli isolates with intI1 gene highlight the potential risk of the ditch’s water to human health. An attenuation effect of MDR E. coli isolates in the outlet water was observed.

Multiple Antibiotic Resistance in Escherichia coli Isolates from Fecal and Water Sources in Laguna Lake, Philippines

Due to the misuse and overuse of antibiotics, antibiotic residues accumulate in natural environments, leading to the development of antibiotic-resistant bacteria (ARBs). The presence of ARBs in bodies of water poses health hazards to the surrounding community. This study focused on Laguna Lake, the largest lake in the Philippines, which serves as a water source for agriculture and domestic purposes. We aimed to detect the presence of antibiotic-resistant Escherichia coli from the lake waters and potential reservoirs of resistance as well as determine the multiple antibiotic resistance (MAR) indices of the isolates. E. coli (n = 450) was isolated from fecal-associated samples (chicken, cow, pig, human, sewage) and water samples (sites in Laguna Lake and selected river tributaries). The isolates were subjected to an antibiotic resistance assay using VITEK 2®. Among the 16 antibiotics tested, the isolates exhibited varying resistance to 14, but complete susceptibility to amikacin and tigecycline was observed. Isolates were most frequently resistant to ampicillin (196/450, 43.6%). Among fecal-associated samples, chicken isolates exhibited the highest MAR index (0.174), whereas samples from Pila River exhibited the highest MAR index (0.152) among water samples. The results of this study demonstrate the presence of multidrug-resistant E. coli in samples collected around Laguna Lake and reveal fecal and sewage sources as potential reservoirs of ARBs in the water body. With this information, the public is urged to use antibiotics responsibly to help mitigate the spread of antibiotic resistance.

Non-antibiotic Approaches to Preventing Pediatric UTIs: a Role for D-Mannose, Cranberry, and Probiotics?

While antibiotics have been a staple in the management and even prevention of urinary tract infections (UTIs), it is not without significant consequences due to intolerance and development of antibiotic resistant bacteria. These concerns necessitate alternatives to antibiotic use in the management of pediatric UTIs. This review seeks to evaluate non-antibiotic means of preventing UTI in the pediatric population. The search for preventative alternatives to antibiotics has included D-mannose, cranberry, and probiotics. These products similarly work through competitive inhibition of uropathogens in the urinary tract. Pediatric studies exist highlighting the use of cranberry extract/juice and probiotics in UTI prevention, although significant heterogeneity amongst studies have limited overarching recommendations for their use. Data of D-mannose use is extrapolated from adult literature. More studies are required in the utility of each treatment, with some emphasis on larger sample sizes and clarifications regarding dosing and formulation.

Antibiotic Resistance in the Drinking Water: Old and New Strategies to Remove Antibiotics, Resistant Bacteria, and Resistance Genes.

Bacterial resistance is a naturally occurring process. However, bacterial antibiotic resistance has emerged as a major public health problem in recent years. The accumulation of antibiotics in the environment, including in wastewaters and drinking water, has contributed to the development of antibiotic resistant bacteria and the dissemination of antibiotic resistance genes (ARGs). Such can be justified by the growing consumption of antibiotics and their inadequate elimination. The conventional water treatments are ineffective in promoting the complete elimination of antibiotics and bacteria, mainly in removing ARGs. Therefore, ARGs can be horizontally transferred to other microorganisms within the aquatic environment, thus promoting the dissemination of antibiotic resistance. In this review, we discuss the efficiency of conventional water treatment processes in removing agents that can spread/stimulate the development of antibiotic resistance and the promising strategies for water remediation, mainly those based on nanotechnology and microalgae. Despite the potential of some of these approaches, the elimination of ARGs remains a challenge that requires further research. Moreover, the development of new processes must avoid the release of new contaminants for the environment, such as the chemicals resulting from nanomaterials synthesis, and consider the utilization of green and eco-friendly alternatives such as biogenic nanomaterials and microalgae-based technologies.

Antibiotics in the environment: A review

Due to overuse and misuse of antibiotics in human medicines, veterinary medicines, agriculture, aquaculture and their persistence, before the covid-19 pandemic, antibiotics were considered as most emerging pollutants of the 21st century. Due to population growth, economic development and longevity during the last 25 years in the low and middle-income group countries the prescription and use of antibiotics have increased many folds. This results in presence of antibiotics in all the compartments of the environment i.e. surface water, groundwater, soil, milk, plants, vegetables, fruits and fish. Wastewater generated from hospitals, households, aquaculture is the hotspot of the residual antibiotics. Human health is adversely affected by consuming antibiotics contaminated plant and animal food and by drinking antibiotics contaminated water. Antibiotics not only causes the development of antibiotic-resistant bacteria and genes resistant to antibiotics but also affects the ecosystem, biogeochemical cycling, microbial growth and microbial population. The major threat to humans due to the indiscriminate use of antibiotics is the development of multiple antibiotic-resistant bacteria. The concentration of the antibiotics in the aquatic environment, milk samples, plants, vegetables, and fruits consumed by humans and their impact on animals and humans are documented in this review.

Geographic variation of antibiotic resistance in E. coli isolated from drinking water and foodstuffs in Sylhet division of Bangladesh

Geographical variation of antibiotic resistance (ABR) is a great difficulty for the empirical antibiotic’s prescription for infectious diseases. The development of ABR in bacteria is believed in associated with some risk factors. In addition, ABR against antibiotic drugs due to its associated risk factors has been linked with various negative health outcomes. However, almost no information is available in relation to such issues of bacteria isolated from environmental samples in Bangladesh. This study first time describes that information’s of E. coli isolated from foodstuffs and drinking water in urban and rural areas in Bangladesh. We isolated E. coli from 72 samples (urban 36 and rural 36) from foodstuffs (rice, carrot and tomato) and drinking water (filtered water, tea stall water and tube well water) in Sylhet division, and tested the antibiogram by disc diffusion and spread plate methods against 14 commonly used antibiotics. Sociodemographic data by using a structured questionnaire were collected from 577 participant’s child, adolescent and old in urban and rural areas. In this study, we found the occurrence of E. coli isolated from foodstuffs and drinking water is 33.33% and 11.11% in urban and rural areas respectively. This study represents E. coli is resistant (100%) to AMP, AMX, E and P in both the urban and rural areas. However, CTX (83%), C (100%), COT (33%), GEN (83%), DO (17%), AK (83%) and NA (50%) are resistant only in the urban but not rural area. On the other hand, AZM (100%), CIP (100%) and TE (100%) are completely sensitive to E.coli in both the urban and rural areas whereas CTX (100%) is only to rural E.coli. Importantly, multiple antibiotic resistance (MAR) of E.coli is significantly higher in urban than rural samples. Moreover, our data also indicates that ABR associated risk factors link with negative health outcomes in Sylhet division.

Antimicrobial vascular grafts: experimental development and implementation in clinical practice

Prosthetic vascular graft infections, followed by severe complications and high mortality rates, remain one of the main issues in cardiovascular surgery. Therefore, the development of antimicrobial coating for vascular prostheses that is capable of preventing the infection is a very relevant field. This review outlines the main factors of development of antibiotic-resistant bacteria, the main directions in the development of vascular prostheses with an antimicrobial coating, and the prospects for the application of antimicrobial peptides and cationic amphiphiles as antimicrobial coating to develop an infection-resistant vascular prosthesis.

Potential Application of PCR Based Molecular Methods in Fish Pathogen Identification: A Review

Molecular biology developments have led to fast growth in new methods for fish disease diagnosis. Molecular diagnostic methods are rapid and more specific, more sensitive than the culture of pathogens, serology, histology, and biochemical methods which are traditionally utilized to identify causative agent fish disease. Molecular diagnostic methods are valuable for detecting specific pathogens that are difficult to culture in vitro or require a long cultivation period and it significantly more rapid in providing results compared to culture. It enables earlier informed decision-making and rapid diagnosis of bacteremia, particularly for low levels of bacteria in specimens. Molecular techniques which have the major significance are mainly PCR-based molecular diagnostic methods including Polymerase Chain Reaction (PCR), Real-Time Polymerase Chain Reaction (RT-PCR), Multiplex Polymerase Chain Reaction (multiplexPCR), and Random Amplified Polymorphic DNA (RAPD). These have been increasingly utilized to diagnose fish disease for the last recent years. Molecular diagnostic methods can detect pathogens from asymptomatic fish, so disease outbreaks could be prevented. As a consequence, antibiotic treatment can be reduced and the development of antibiotic-resistant bacteria can be eliminated. In this review paper, we attempt to summarize the potentiality of PCR-based molecular diagnostic methods and their application in fish pathogen identification.