The mazEF toxin-antitoxin system as a novel antibacterial target in Acinetobacter baumannii

Although analysis of toxin-antitoxin (TA) systems can be instructive, to date, there is no information on the prevalence and identity of TA systems based on a large panel of Acinetobacter baumannii clinical isolates. The aim of the current study was to screen for functional TA systems among clinical isolates of A. baumannii and to identify the systems' locations. For this purpose, we screened 85 A. baumannii isolates collected from different clinical sources for the presence of the mazEF, relBE and higBA TA genes. The results revealed that the genes coding for the mazEF TA system were commonly present in all clinical isolates of A. baumannii. Reverse transcriptase-polymerase chain reaction analysis showed that transcripts were produced in the clinical isolates. Our findings showed that TA genes are prevalent, harboured by chromosomes and transcribed within A. baumannii. Hence, activation of the toxin proteins in the mazEF TA system should be investigated further as an effective antibacterial strategy against this bacterium

Humoral immune consequences of Staphylococcus aureus ST239-associated bacteremia

The humoral immune responses against 46 different staphylococcal antigens in 27 bacteremia patients infected by clonally related methicillin-resistant Staphylococcus aureus (MRSA) strains of a single sequence type (ST) 239 were investigated. A group of non-infected patients (n = 31) hospitalized for different reasons served as controls. All strains were confirmed as ST 239 by S. aureus and mecA-specific PCR, spa, and multi-locus sequence typing (MLST). In each bacteremia patient, a unique pattern of S. aureus antigen-specific immune responses after infection was observed. Antibody levels among bacteremia patients were significantly higher than controls for HlgB (P = 0.001), LukD (P = 0.009), LukF (P = 0.0001), SEA (P = 0.0001), SEB (P = 0.011), SEC (P = 0.010), SEQ (P = 0.049), IsaA (P = 0.043), IsdA (P = 0.038), IsdH (P = 0.01), SdrD (P = 0.001), SdrE (P = 0.046), EsxA (P = 0.0001), and SA0104 (P = 0.0001). On the other hand, the antibody levels were significantly higher among controls for SSL3 (P = 0.009), SSL9 (P = 0.002), and SSL10 (P = 0.007) when the IgG level on the day of infection was compared with that measured on the day of admission. Diversity was observed in the immune response against the antigens. However, a set of antigens (IsaA, IsdA, IsdH, SdrD, and HlgB) triggered a similar type of immune response in different individuals. We suggest that these antigens could be considered when developing a multi-component (passive) vaccine. SEA and/or its specific antibodies seem to play a critical role during ST239 MRSA bacteremia and SEA-targeted therapy may be a strategy to be considered

Virulence genes expression among methicillin-resistant staphylococcus aureusisolated form cancer and non-cancer patients

Relative quantitative real-time reverse transcriptase polymerase chain reaction (qPCR) assay was designed and applied in order to study the expression levels of selected genes encoding the adherence and toxins virulent factors. Relative quantification qPCR showed a significant higher expression level of common genes tested among strains isolated from cancer patients not only within the clone but also among different lineages. This study demonstrated that although all MRSA strains studied from cancer and non-cancer patients possessed several virulence determinantsthe expression rather than presence of virulence determinants may mediate higher pathogenicity potential. These data will aid in developing more effective infection control strategy to improve the management of MRSA infection in cancer patients

Wide Distribution of Virulence Genes among Enterococcus faecium and Enterococcus faecalis Clinical Isolates

Enterococcus, a Gram-positive facultative anaerobic cocci belonging to the lactic acid bacteria of the phylum Firmicutes, is known to be able to resist a wide range of hostile conditions such as different pH levels, high concentration of NaCl (6.5), and the extended temperatures between 5 degrees C and 65 degrees C. Despite being the third most common nosocomial pathogen, our understanding on its virulence factors is still poorly understood. The current study was aimed to determine the prevalence of different virulence genes in Enterococcus faecalis and Enterococcus faecium. For this purpose, 79 clinical isolates of Malaysian enterococci were evaluated for the presence of virulence genes. pilB, fms8, efaAfm, and sgrA genes are prevalent in all clinical isolates. In conclusion, the pathogenicity of E. faecalis and E. faecium could be associated with different virulence factors and these genes are widely distributed among the enterococcal species

VITILIGO: SYMPTOMS, PATHOGENESIS AND TREATMENT

Vitiligo is an acquired cutaneous disorder of pigmentation, with an incidence of 0.5 to 2 worldwide. There are three major hypotheses for the pathogenesis of vitiligo that are not exclusive of each other: biochemical/cytotoxic, neural and autoimmune. Recent data provide strong evidence supporting an autoimmune pathogenesis of vitiligo. As vitiligo can have a major effect on quality of life, treatment can be considered and should preferably begin early when then disease is active. Current treatment modalities are directed towards stopping progression of the disease and achieving repigmentation. Therapies include corticosteroids, topical immunomodulators, photo(chemo)therapy, surgery, combination therapies and depigmentation of normally pigmented skin. It seems that traditional Chinese medicine could be more effective than the current treatment for vitligo

Differential between multi-drug resistance pattern of extended spectrum β-lactamases producing E. coli and K. pneumoniae

The current study aimed to determine the prevalence of Extended-Spectrum β-Lactamases (ESBLs) in Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) strains isolated from patients with Urinary Tract Infections (UTIs), to study the association between presence of ESBL enzyme and multi-drug resistance strains and finally, and to investigate the predominant ESBL gene in E. coli and K. pneumoniae. The strains were examined for the presence of ESBL as a Clinical Laboratory Standards Institute (CLSI) guideline. Among 284 clinical isolates, 52.8 (n = 150) and 47.2 (n =134) were E. coli and K. pneumoniae, respectively, and 110 strains were ESBL producer, which 68 strains were K. pneumoniae and 42 strains were E. coli. Significant difference observed between the TEM gene and ciprofloxacin resistant in E. coli (P ≤ 0.05) while no significant difference observed between CTX-M, SHV genes and the other multi-drug resistant E. coli. No significant difference observed between CTX-M, TEM, and SHV genes and multi-drug resistant K. pneumoniae. In conclusion, spreading of ESBL-producing strains is a concern, as it causes limitations to the antimicrobial agents for optimal treatment of patients. Prevalence of ESBLs was more observed in K. pneumoniae than E. coli. In addition, TEM gene was more prevalent in E. coli and resistance to ciprofloxacin was predominant in E. coli

High level aminoglycoside resistance and distribution of the resistance genes in Enterococcus faecalis and Enterococcus faecium from teaching hospital in Malaysia

Background: Enterococcus faecium and Enterococcus faecalis are among the predominant species causing hospital-acquired infections. Currently, enterococcal infections are treated using combination therapy of an aminoglycoside with cell-wall active agents, which led to high level aminoglycoside resistance (HLAR) and vancomycin resistance (VRE) among enterococci. The aim of this study was to determine the prevalence of HLAR and the distribution of the resistance genes among clinical E. faecalis and E. faecium isolates in Malaysia. Materials and methods: Seventy-five enterococci isolates recovered from different clinical sources were re-identified by subculturing on selective medium, Gram staining, biochemical profiling (API 20 Strep), and 16s rRNA sequencing. Antimicrobial susceptibility testing (AST) was performed using Kirby-Bauer disc diffusion, E-test, and broth microdilution methods. PCR amplification was used to detect the presence of aminoglycoside modifying enzyme (AME) genes [aac(6’)-Ie-aph(2”)-Ia, aph(2”)-Ib, aph(2”)-Ic, aph(2”)-Id, aph(3’)-IIIa]. Descriptive data analysis was used to analyze the antibiotic susceptibility profiles and the distribution of HLAR genes. Results: The majority of the isolates recovered from the clinical samples are E. faecalis (66.7%), with the highest recovery from the pus. The prevalence of HLGR (51%) is higher when compared to HLSR (45–49%). Analysis of the resistance genes showed that bifunctional genes aac(6’)-Ie-aph(2”)-Ia and aph(3’)-IIIa contributed to the HLAR E. faecalis and E. faecium. The other AME genes [aph(2”)-Ib, aph(2”)-Ic, aph(2”)-Id] were not detected in this study. Conclusion: This study provides the first prevalence data on HLAR and the distribution of the AME genes among E. faecalis and E. faecium isolates from Malaysia. These highlight the need for continued antibiotic surveillance to minimize its emergence and further dissemination