临床传染病：开放获取

Antibiotic resistance is threatening the health sectors in different developing countries. The first report on antibiotic resistance in the Kingdom of Bahrain was in 2003. The work was comparing the number of Shigella isolates for the years 1984-1988 and 1994-2001. In 2009 another study investigated 11,886 isolates and 22.6% were ESBLs. Two more studies had covered the prevalence of ESBLs in 2011 and 2014. This time the trend of ESBLs had showed an increase in CTX-M with respective detection percentages of 98% and 93.8%. Even though that there is an increase in the number of ESBLs with a predominance for CTX-M type of ESBLs still no carbapenem resistant isolates were noted as yet.

This study was conducted to evaluate the responsiveness to hepatitis B virus vaccine in adult healthy laboratory workers in the Faculty of Medical Laboratories Sciences at Al Neelain University, Khartoum, Sudan. The study was conducted at Al Neelain University, during the period from April to June 2014. Sixty one blood samples were collected from healthy adult laboratory workers who received 3 doses of recombinant HBV vaccine. Serum samples were obtained by centrifugation and tested using ELISA to quantify the level of hepatitis B surface antibody in order to detect the responders and non-responders. DNA was extracted from plasma samples collected from the same patients and subjected to polymerase chain reaction (PCR) to detect the presence of Interferon gamma (IFN-γ) A&T alleles in both responders and non-responders.

Out of 61 laboratory workers 54 (88.5%) were found responders and 7 (11.5%) were non-responders to hepatitis B vaccine, with higher frequency of non-responsiveness among the males, there was no association between the responsiveness and age.

All responders and 85% of non-responders were positive for IFN-γ A alleles, while 28.5% of responders and 42.8% of non-responders were positive for IFN-γ T alleles. Responsiveness to hepatitis B surface antigen vaccine is affected by gender (higher in females than males) but not age or the presence of A&T allele of interferon gamma gene.

Vancomycin antibiotic is a well-known drug of last resort in the treatment of methicillin-resistant S. aureus (MRSA), but recent studies have shown the emergence of resistance to vancomycin and other antibiotics. This study determines the phenotypic and genotypic prevalence of vancomycin resistant S. aureus (VRSA) among clinical isolates in Zaria Metropolis. A total of 350 suspected Staphylococcal isolates from clinical specimens (blood, urine, high vaginal swab, wound swab, ear swab, urethral swab) submitted to the Medical Microbiology Unit of the selected hospitals in Zaria were collected for the period of 6 months. The antibiotic susceptibility profile of MRSA isolates were determined using disc diffusion method while the minimum inhibitory concentration (MIC) for vancomycin was determined using Etest® gradient method. PCR and sequencing were conducted on the isolates to molecularly detect the presence of mecA and van genes (vanA, vanB, vanC, vanD, vanR and vanXY). Phenotypic VRSA evaluation showed that 3.92% of S. aureus isolates were VRSA, 19.6% of isolates were VISA (vancomycin intermediate S. aureus) and 76.47% of isolates were VSSA (vancomycin susceptible S. aureus). Twelve (12) isolates that had vancomycin MIC range of 4-16 μg/ml were selected for genotypic evaluation of virulent genes. All isolates amplified with 16SrRNA signifying all are S. aureus. The result shows that 58% of the isolates harbors mecA gene, 25% of isolates harbors vanA gene, 67% vanB gene, 41.7% vanC, 58.3% vanD, 83.3% vanR and 83.3% vanXY. The presence of van gene was implicated in generation of Vancomycin resistance isolates.

Although automated susceptibility methods are widely available nowadays, antimicrobial susceptibility testing performed by the Kirby Bauer technique is still being commonly used in many laboratories especially in the developing countries. They provide a simple and inexpensive method for determining susceptibility of various Gram positive and Gram negative organisms against various drugs. The quality of results generated by the laboratory with respect to susceptibility of microorganisms to antimicrobials has an important bearing on patient management and outcomes. Any quality assurance program must include internal quality control (IQC) and external quality assessment. The important IQC measures in disc diffusion susceptibility testing include use of specific Quality Control (QC) strains, batch testing of media and antibiotics, and lot-to-lot verifications of reagents used. QC may be performed daily or weekly as per the workload of the laboratory. Some important causes of QC failure include improper storage of QC strains, media and reagents; errors in inoculums preparation and incubation temperatures; and equipment related issues like calibration errors. Accuracy and reliability of results should be regularly assessed by proficiency testing. If any failure in the QC is noted, corrective and preventive actions must be undertaken to ensure the quality of results generated.

Drug-induced liver injury (DILI) is a major concern in clinical studies as well as in post-marketing surveillance. Several anti-infective drugs had development discontinued due to serious hepatic events- acute liver failure, including liver transplantation or death. The diagnosis of drug-induced liver injury necessitates an initial high degree of suspicion, based on circumstantial evidence. It is a step-by-step process of exclusion. Consequently, a patient in a clinical trial who experiences elevated LFTs that meet Hy’s Law criteria should have causes other than study drug carefully excluded.