Anti-Inflammatory Effects of Zinc Oxide and Berberine in Rats with Dextran Sulfate Sodium (DSS)-Induced Colitis.

Zinc oxide (ZnO) is frequently used in high concentrations to prevent diarrhea in weaning pigs. However, it can produce environmental pollution, because it is not absorbed by the intestines and is excreted in the feces. In studies to identify an alternative substance to ZnO, we used a model of colitis induced by dextran sulfate sodium (DSS) in rats to compare the anti-inflammatory effects of berberine with ZnO. DSS-treated rats displayed weight loss, shortening of the colon, increased fecal water content, and an increase in the disease activity index (DAI). In contrast, DSS + ZnO- and DSS + berberine-treated rats exhibited reduced colon shortening, decreased fecal water content, and a decrease in the DAI. Histological analysis revealed that both ZnO and berberine treatment reduced epithelial cell damage, crypt destruction, and infiltration of inflammatory cells. Moreover, the liver damage index was not significantly different between ZnO and berberine-treated rats. This study indicated that both ZnO and berberine can improve DSS-induced colitis in rats and suggests berberine as an alternative treatment to ZnO that would not cause environmental pollution.

Characterization of Salmonella species from poultry slaughterhouses in South Korea: carry-over transmission of Salmonella Thompson ST292 in slaughtering process.

IMPORTANCE: Salmonella outbreaks linked to poultry meat have been reported continuously worldwide. Therefore, Salmonella contamination of poultry meats in slaughterhouses is one of the critical control points for reducing disease outbreaks in humans. OBJECTIVE: This study examined the carry-over contamination of Salmonella species through the entire slaughtering process in South Korea. METHODS: From 2018 to 2019, 1,097 samples were collected from the nine slaughterhouses distributed nationwide. One hundred and seventeen isolates of Salmonella species were identified using the invA gene-specific polymerase chain reaction, as described previously. The serotype, phylogeny, and antimicrobial resistance of isolates were examined. RESULTS: Among the 117 isolates, 93 were serotyped into Salmonella Mbandaka (n = 36 isolates, 30.8%), Salmonella Thompson (n = 33, 28.2%), and Salmonella Infantis (n = 24, 20.5%). Interestingly, allelic profiling showed that all S. Mbandaka isolates belonged to the lineage of the sequence type (ST) 413, whereas all S. Thompson isolates were ST292. Moreover, almost all S. Thompson isolates (97.0%, 32/33 isolates) belonging to ST292 were multidrug-resistant and possessed the major virulence genes whose products are required for full virulence. Both serotypes were distributed widely throughout the slaughtering process. Pulsed-field gel electrophoretic analysis demonstrated that seven S. Infantis showed 100% identities in their phylogenetic relatedness, indicating that they were sequentially transmitted along the slaughtering processes. CONCLUSIONS AND RELEVANCE: This study provides more evidence of the carry-over transmission of Salmonella species during the slaughtering processes. ST292 S. Thompson is a potential pathogenic clone of Salmonella species possibly associated with foodborne outbreaks in South Korea.

Combined antimicrobial effect of two peptide nucleic acids against Staphylococcus aureus and S. pseudintermedius veterinary isolates.

BACKGROUND: Staphylococcus aureus and S. pseudintermedius are the major etiological agents of staphylococcal infections in humans, livestock, and companion animals. The misuse of antimicrobial drugs has led to the emergence of antimicrobial-resistant Staphylococcus spp., including methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP). One novel therapeutic approach against MRSA and MRSP is a peptide nucleic acid (PNA) that can bind to the target nucleotide strands and block expression. Previously, two PNAs conjugated with cell-penetrating peptides (P-PNAs), antisense PNA (ASP)-cmk and ASP-deoD, targeting two essential genes in S. aureus, were constructed, and their antibacterial activities were analyzed. OBJECTIVES: This study analyzed the combined antibacterial effects of P-PNAs on S. aureus and S. pseudintermedius clinical isolates. METHODS: S. aureus ATCC 29740 cells were treated simultaneously with serially diluted ASP-cmk and ASP-deoD, and the minimal inhibitory concentrations (MICs) were measured. The combined P-PNA mixture was then treated with S. aureus and S. pseudintermedius veterinary isolates at the determined MIC, and the antibacterial effect was examined. RESULTS: The combined treatment of two P-PNAs showed higher antibacterial activity than the individual treatments. The MICs of two individual P-PNAs were 20 and 25 µM, whereas that of the combined treatment was 10 µM. The application of a combined treatment to clinical Staphylococcus spp. revealed S. aureus isolates to be resistant to P-PNAs and S. pseudintermedius isolates to be susceptible. CONCLUSIONS: These observations highlight the complexity of designing ASPs with high efficacy for potential applications in treating staphylococcal infections in humans and animals.

Quantitative risk assessment of foodborne Salmonella illness by estimating cooking effect on eggs from retail markets.

In this study, we performed a quantitative microbial risk assessment (QMRA) of Salmonella through intake of egg consumption after cooking (dry-heat, moist-heat, and raw consumption). Egg samples (n = 201) from retail markets were analyzed for the presence of Salmonella. In addition, temperature and time were investigated during egg transit, storage, and display. A predictive model was developed to characterize the kinetic behavior of Salmonella in eggs, and data on egg consumption and frequency were collected. Eventually, the data was simulated to estimate egg-related foodborne illnesses. Salmonella was not found in any of the 201 egg samples. Thus, the estimated initial contamination level was -4.0 Log CFU/g. With R2 values of 0.898 and 0.922, the constructed predictive models were adequate for describing the fate of Salmonella in eggs throughout distribution and storage. Eggs were consumed raw (1.5%, 39.2 g), dry-heated (57.5%, 43.0 g), and moist-heated (41%, 36.1 g). The probability of foodborne Salmonella illness from the consumption of cooked eggs was evaluated to be 6.8×10-10. Additionally, the probability of foodborne illness not applied cooking methods was 1.9×10-7, indicating that Salmonella can be reduced by cooking. Therefore, the risk of Salmonella infection through consumption of eggs after cooking might be low in S. Korea.

Acid tolerance of enterohemorrhagic Escherichia coli O157:H7 strain ATCC 43894 and its relationship with a large virulence plasmid pO157.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen that causes a severe intestinal infection including hemolytic uremic syndrome in humans. Various factors contribute to its pathogenesis, including a large virulence plasmid pO157. This F-like 92-kb plasmid is isolated in virtually all clinical EHEC isolates, and is considered a hallmark of EHEC virulence. A previous report stated that removal of pO157 from EHEC ATCC 43894 induced overexpression of GadAB that are essential in glutamate-dependent acid resistance (GDAR) system, yet the mechanism remains elusive. Based on this observation, we surmised that pO157 is involved in the regulation of GDAR system. We comparatively analyzed 43894 and its pO157-cured (ΔpO157) mutant 277 for i) their acid resistance, ii) changes in the transcriptional profiles and iii) expression of GDAR associated genes/proteins. Survivability of 43894 upon exposure to acidic conditions was significantly lower than the ΔpO157 mutant. In addition, RNA-sequencing revealed that genes involved in GDAR were significantly down-regulated in 43894 when compared to the ΔpO157 mutant. Exogenous expression of GadE in 43894 led to expression of GadAB, suggesting possible intervention of pO157 in GDAR regulation. Despite these findings, reintroduction of pO157 into 277 did not reverted Gad overexpression. Likewise, removing pO157 from 43894 using the plasmid incompatibility method did not induce Gad overexpression as shown in 277. Taken together, the results suggest that variation in acid resistance among EHEC isolates exists, and the large virulence plasmid pO157 has no effect on weak acid resistance phenotype displayed in 43894.

Development of antisense peptide-peptide nucleic acids against fluoroquinolone-resistant Escherichia coli.

BACKGROUND: Fluoroquinolones (FQs) are potent and broad-spectrum antibiotics commonly used to treat MDR bacterial infections, but bacterial resistance to FQs has emerged and spread rapidly around the world. The mechanisms for FQ resistance have been revealed, including one or more mutations in FQ target genes such as DNA gyrase (gyrA) and topoisomerase IV (parC). Because therapeutic treatments for FQ-resistant bacterial infections are limited, it is necessary to develop novel antibiotic alternatives to minimize or inhibit FQ-resistant bacteria. OBJECTIVES: To examine the bactericidal effect of antisense peptide-peptide nucleic acids (P-PNAs) that can block the expression of DNA gyrase or topoisomerase IV in FQ-resistant Escherichia coli (FRE). METHODS: A set of antisense P-PNA conjugates with a bacterial penetration peptide were designed to inhibit the expression of gyrA and parC and were evaluated for their antibacterial activities. RESULTS: Antisense P-PNAs, ASP-gyrA1 and ASP-parC1, targeting the translational initiation sites of their respective target genes significantly inhibited the growth of the FRE isolates. In addition, ASP-gyrA3 and ASP-parC2, which bind to the FRE-specific coding sequence within the gyrA and parC structural genes, respectively, showed selective bactericidal effects against FRE isolates. CONCLUSIONS: Our results demonstrate the potential of targeted antisense P-PNAs as antibiotic alternatives against FQ-resistance bacteria.

Current Status of Q Fever and the Challenge of Outbreak Preparedness in Korea: One Health Approach to Zoonoses.

Human Q fever, a zoonosis caused by Coxiella burnetii, presents with diverse clinical manifestations ranging from mild self-limited febrile illnesses to life-threatening complications such as endocarditis or vascular infection. Although acute Q fever is a benign illness with a low mortality rate, a large-scale outbreak of Q fever in the Netherlands led to concerns about the possibility of blood transfusion-related transmission or obstetric complications in pregnant women. Furthermore, a small minority (< 5%) of patients with asymptomatic or symptomatic infection progress to chronic Q fever. Chronic Q fever is fatal in 5-50% of patients if left untreated. In South Korea, Q fever in humans was designated as a notifiable infectious disease in 2006, and the number of Q fever cases has increased sharply since 2015. Nonetheless, it is still considered a neglected and under-recognized infectious disease. In this review, recent trends of human and animal Q fever in South Korea, and public health concerns regarding Q fever outbreaks are reviewed, and we consider how a One Health approach could be applied as a preventive measure to prepare for zoonotic Q fever outbreaks.

Mutating both relA and spoT of enteropathogenic Escherichia coli E2348/69 attenuates its virulence and induces interleukin 6 in vivo.

Here, we report for the first time that disrupting both relA and spoT genes in enteropathogenic Escherichia coli E2348/69 can attenuate its virulence and significantly induce interleukin 6 (IL-6) in vivo. Our experimental analyses demonstrated that an E2348/69 ΔrelAΔspoT double mutant strain derepressed the expression of type IV bundle forming pilus (BFP) and repressed the expression of glutamate decarboxylase (GAD) and locus of enterocyte effacement (LEE). Whole genome-scale transcriptomic analysis revealed that 1,564 EPEC genes were differentially expressed in the ΔrelAΔspoT double mutant strain (cut-off > two-fold). Such depletion of relA and spoT attenuated the virulence of E2348/69 in a Caenorhabditis elegans infection model. Surprisingly, IL-6 was highly induced in porcine macrophages infected with the ΔrelAΔspoT double mutant strain compared to those with its wildtype strain. Coinciding with these in vitro results, in vivo murine peritoneal challenge assays showed high increase of IL-6 and improved bacterial clearance in response to infection by the ΔrelAΔspoT double mutant strain. Taken together, our data suggest that relA and spoT play an essential role in regulating biological processes during EPEC pathogenesis and that their depletion can affect host immune responses by inducing IL-6.

Salmonella Risk Assessment in Poultry Meat from Farm to Consumer in Korea.

This study predicted Salmonella outbreak risk from eating cooked poultry in various methods. The incidence of Salmonella in poultry meat and the environment from farm to home for consumption was investigated. To develop the predictive models, Salmonella growth data were collected at 4-25 °C during storage and fitted with the Baranyi model. The effects of cooking on cell counts in poultry meat were investigated. Temperature, duration, and consumption patterns were all searched. A simulation in @Risk was run using these data to estimate the probability of foodborne Salmonella disease. In farm, Salmonella was detected from only fecal samples (8.5%; 56/660). In slaughterhouses, Salmonella was detected from feces 16.0% (38/237) for chicken and 19.5% (82/420) for duck) and from carcasses of each step (scalding, defeathering, and chilling) by cross contamination. In chicken (n = 270) and duck (n = 205), Salmonella was detected in 5 chicken (1.9%) and 16 duck meat samples (7.8%). Salmonella contamination levels were initially estimated to be -3.1 Log CFU/g and -2.5 Log CFU/g, respectively. With R2 values between 0.862 and 0.924, the predictive models were suitable for describing the fate of Salmonella in poultry meat with of 0.862 and 0.924. The Salmonella was not detected when poultry meat cooks completely. However, if poultry meat contaminated with Salmonella were cooked incompletely, Salmonella remained on the food surface. The risk of foodborne Salmonella disease from poultry consumption after cooking was 3.0 × 10-10/person/day and 8.8 × 10-11/person/day in South Korea, indicating a low risk.

Characterization of transcriptional activities at a divergent promoter of the type VI secretion system in enterohemorrhagic Escherichia coli O157:H7.

The type VI secretion system (T6SS) is a novel secretion system found in many Gram-negative bacteria that plays a role in bacterial competition, virulence, and host immune evasion. The enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL933 has a single functional T6SS gene cluster. In this study, we attempted to characterize the transcriptional pattern of the T6SS effector gene Z0264 in EDL933. Transcriptional analyses showed that Z0264 and other T6SS genes were transcribed in vitro in a growth-phase-dependent manner, but Z0264 was not secreted in the rich medium. Using adapter- and radioactivity-free transcription start site analysis, we identified an overlapping divergent promoter between Z0264 and Z0265. A ß-galactosidase assay with truncated promoter regions showed that the divergent promoter is functional. In addition, we demonstrated the role of H-NS as a repressor in the transcription of Z0264. Notably, the cDNA PCR assay showed that the mRNA transcript from the Z0264 promoter did not include the entire main T6SS cluster, suggesting segmented gene expression by multiple promoters in the T6SS cluster. In conclusion, we identified a divergent promoter for Z0264 located in the T6SS cluster of EDL933 and characterized its in vitro transcriptional activity during growth. Our findings provide insights and a preliminary understanding of the regulatory mechanisms underlying T6SS transcription.

Pathophysiology of enteropathogenic Escherichia coli during a host infection.

Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.

Hematologic Emergencies in the Postoperative Neurointensive Care Unit Setting: Illustrative Case Series and Differential Diagnosis.

OBJECTIVES: Investigating the development of acute thrombocytopenia, differential etiologies, and potentially the rare manifestation of disseminated intravascular coagulation after brain tumor resection of primary and secondary malignancies. MATERIALS AND METHODS: We performed a retrospective review of a case series of post-operative neurosurgical patients which developed thrombocytopenia. We applied National Library of Medicine search engine methodology using the terms disseminated intravascular coagulation and brain tumors. RESULTS: We report clinical, radiographic, and laboratory data of four Neurointensive care unit patients that developed thrombocytopenia, three with disseminated intravascular coagulation after craniotomy, and one with heparin-induced thrombocytopenia masquerading as low grade disseminated intravascular coagulation. All four patients presented with cranial lesions and underwent neurosurgical resection. Underlying disorders included: high grade glioma, stage IV lung cancer with metastases, and meningioma. One patient survived and was able to recover after several days of hospitalization, while another patient was discharged to hospice. Search results illustrated that disseminated intravascular coagulation in the presence of glioblastoma multiforme is rare (only four patients) and may be due to a release of coagulation factors like tissue plasminogen activator, treated with antifibrinolytic agents. Searching the terms disseminated intravascular coagulation and brain tumors in the National Library of Medicine search engine yielded 116 results; eight were relevant to our study. CONCLUSIONS: Correlation of thrombocytopenia after neurosurgery for glioblastoma multiforme and disseminated intravascular coagulation is rare. It is extremely challenging to manage these patients with concomitant deep vein thrombosis/pulmonary embolism and intracranial bleeding. Heparin-induced thrombocytopenia is common yet possesses a different hematological coagulation profile and has more pharmacologic options. Neurointensive care unit teams should recognize intraoperative and post-operative disseminated intravascular coagulation cases, and heparin-induced thrombocytopenia in the differential of post-operative thrombocytopenia with specific pharmacologic interventions.

Isolation and characterization of Salmonella spp. from food and food contact surfaces in a chicken processing factory.

The presence of Salmonella serotypes is a major safety concern of the food industry and poultry farmers. This study aimed to isolate and identify Salmonella spp. from a chicken processing facility by PCR and pulsed-field gel electrophoresis (PFGE). In addition, the biofilm-forming abilities of the isolated bacteria on stainless steel, silicone rubber, plastic, and chicken skin were also investigated. PCR was used for the confirmation of Salmonella serotypes, and then gene similarity within the same serotype was analyzed by PFGE. As a result, 26 S. Enteritidis isolates were detected at a high rate from both food contact surfaces and chicken products during processing. All of them were 100% genetically identical to the same bacteria. The results indicated that the virulence factors and effective biofilm-forming ability of S. Enteritidis isolates could affect human health and economic revenue. It was also suggested that the visual observation of food and food contact surfaces could be a great concern in the future. The continuous monitoring of S. Enteritidis molecular and biofilm characteristics is needed to increase food safety.

Supraclavicular Resection of a Cervical Rib Causing Thoracic Outlet Syndrome: 2-Dimensional Operative Video.

Presence of a cervical rib results from overdevelopment of the seventh cervical vertebrae.1-3 The cervical rib along with scalene muscles can cause neurogenic thoracic outlet syndrome.4,5 Rib resection is typically done via anterior approach, using either supraclavicular or transaxillary route.6,7 We present an operative video detailing supraclavicular resection of a cervical rib causing neurogenic thoracic outlet syndrome with direct decompression of the lower trunk of the brachial plexus. The patient presented with severe symptoms including hand atrophy. We were able to directly visualize the rib and resect it, along with scalene musculature. We present 3-mo follow-up data noting clinical improvement in neuropathic symptoms.

Molecular characteristics of extended-spectrum ß-lactamase/AmpC-producing Salmonella enterica serovar Virchow isolated from food-producing animals during 2010-2017 in South Korea.

Global dissemination of non-typhoidal Salmonella producing extended-spectrum ß-lactamase (ESBL) is a public-health concern. Recently, the prevalence of Salmonella spp. resistant to third-generation cephalosporins has been increasing in food-producing animals in Korea. In this study, we investigated resistance mechanisms and molecular characteristics of S. Virchow isolates resistant to extended-spectrum cephalosporins (ESCs). We obtained 265 S. Virchow isolates from fecal and carcasses samples of cattle (n = 2), pigs (n = 7), and chickens (n = 256) during 2010-2017, and observed high ESC-resistance (63.8%, 169/265); most of the resistant isolates (96.4%) were obtained from chickens. ESC-resistant S. Virchow isolates (n = 169) showed significantly higher resistance rates to other antimicrobials (especially aminoglycosides and tetracycline, p-value <0.0001), as well as prevalence of multidrug resistance, than did ESC-susceptible S. Virchow isolates (n = 96). All ESC-resistant S. Virchow produced CTX-M-15-type ESBL (n = 147) and/or CMY-2-type AmpC ß-lactamase (n = 23). ESC-resistant S. Virchow represented seven pulsotypes, predominantly composed of type II (58.6%) and III (26.0%), detected in 69 farms in 10 provinces, and 33 farms in 7 provinces, respectively. Genes encoding ESC-resistance were horizontally transferred by conjugation to recipient E. coli J53; this was demonstrated in 28.8% (42/146) of blaCTX-M-15-positive isolates and in 50.0% (11/22) of blaCMY-2-positive isolates. All conjugative plasmids carrying blaCTX-M-15 and blaCMY-2 genes belonged to ST2-IncHI2 and ST12/CC12-IncI1, respectively. Genetic features of transferred bla genes were involved with ISEcp1 in both blaCTX-M-15 and blaCMY-2; ISEcp1 plays a critical role in the efficient capture, expression, and mobilization of bla genes. In addition to blaCTX-M-15 genes, resistance markers to aminoglycosides and/or tetracycline were co-transferred to recipient E. coli J53. Our results show a high prevalence of ESBL-producing S. Virchow in chickens and chicken carcasses. Specific blaCTX-M-15 and blaCMY-2-carrying S. Virchow clones and plasmids were predominant in food-producing animals nationwide. Restriction of antimicrobial use and proper biosecurity practices at the farm level should be urgently implemented in the poultry industry.

The Use of a Novel Heads-Up Display (HUD) to View Intra-Operative X-Rays During a One-Level Cervical Arthroplasty.

BACKGROUND: In a standard surgical operating room, advanced imaging is projected on a separate monitor screen away from the surgical field of view. This setup requires surgeons to repeatedly shift their attention between the operative field and a screen. Such movement may result in a disruption of focus that can extend surgical time, cause physical strain, and lead to surgical errors. A potential solution to this inefficiency in the surgical workflow is to use a heads-up display (HUD) to mirror what is being displayed. A HUD projects preoperative or intraoperative imaging over the surgical field, allowing surgeons to visualize both as they perform surgery. CASE DESCRIPTION: We performed a single-level arthroplasty for a patient with right-sided disc herniation at C6-7. A HUD was used by the lead surgeon to continuously view intraoperative X-rays without needing to repeatedly turn away from the surgical field while placing Caspar pins into the C6 and C7 vertebral bodies, and malleating trials and the artificial disc into the disc space. CONCLUSIONS: Following surgery, the patient experienced resolution of his preoperative right arm and hand paresthesia and regained full strength. This case describes the novel use of the Moverio BT-35E Smart Glasses (Epson Inc, Suwa, Japan) HUD during a spine procedure.

A Novel Peptide Nucleic Acid against the Cytidine Monophosphate Kinase of S. aureus Inhibits Staphylococcal Infection In Vivo.

Here, we report a novel bactericidal peptide nucleic acid (PNA) that can induce the antisense effect on the cytidine monophosphate kinase (Cmk) of Staphylococcus aureus, a putative essential component for bacterial species. Based on the genome sequence of S. aureus N315, a set of PNA conjugates with a bacterial penetration peptide, (KFF)3K, were synthesized to target the seven potentially essential genes (cmk, deoD, ligA, smpB, glmU, pyrH, and ftsA) and further evaluated for their antibacterial properties in vitro as well as in vivo. The results demonstrated that two peptide-conjugated PNAs (P-PNAs), antisense P-PNA (ASP)-cmk1 and ASP-deoD1, targeting either the cmk or the deoD genes, had the strongest inhibitory effects on the growth of S. aureus ATCC 29740 (a bovine mastitic milk isolate) in a dose-dependent manner. In vivo application of ASP-cmk1 resulted in a significant reduction of bacterial loads in mice intraperitoneally infected with a sublethal dose of S. aureus. Moreover, ASP-cmk1 significantly increased the survival rate of the breast-fed infant mice after intramammary infection of the lactating CD-1 mice. Taken together, our characterization of ASP-cmk1 demonstrated its bactericidal activity against S. aureus as well as its effectiveness in vivo.

Antisense peptide nucleic acids as a potential anti-infective agent.

Antibiotics have long been used for anti-infective control of bacterial infections, growth promotion in husbandry, and prophylactic protection against plant pathogens. However, their inappropriate use results in the emergence and spread of multiple drug resistance (MDR) especially among various bacterial populations, which limits further administration of conventional antibiotics. Therefore, the demand for novel anti-infective approaches against MDR diseases becomes increasing in recent years. The peptide nucleic acid (PNA)-based technology has been proposed as one of novel anti-infective and/or therapeutic strategies. By definition, PNA is an artificially synthesized nucleic acid mimic structurally similar to DNA or RNA in nature and linked one another via an unnatural pseudo-peptide backbone, rendering to its stability in diverse host conditions. It can bind DNA or RNA strands complimentarily with high affinity and sequence specificity, which induces the target-specific gene silencing by inhibiting transcription and/or translation. Based on these unique properties, PNA has been widely applied for molecular diagnosis as well as considered as a potential anti-infective agent. In this review, we discuss the general features of PNAs and their application to various bacterial pathogens as new anti-infective or antimicrobial agents.