Use Of Vancomycin For Treatment Research Articles

Phenotypic and Molecular Identification of Vancomycin Resistance in Clinical Staphylococcus Aureus Isolates in Osogbo, Nigeria.

The use of vancomycin for treatment of serious infections caused by MRSA strains has resulted in emergence of vancomycin-resistant Staphylococcus aureus (VRSA) in clinical settings. Following our previous report of phenotypic VRSA in Nigeria, the current study attempts to determine the genetic basis underlying this resistance. Over a period of 6 months, non-duplicate clinical S. aureus isolates from 73 consecutive patients with infective conditions at Ladoke Akintola University of Technology Teaching Hospital, Osogbo were tested against a panel of eight selected antibiotics by disk diffusion test. The Epsilom test strip was used to determine vancomycin minimum inhibitory concentration (MIC) and polymerase chain reaction (PCR) assay to amplify nuc, mecA, vanA, and vanB genes. Of 73 isolates, 61 (83.6%) had MIC of ≤2 μg/ml, 11 (15.1%) had 4–8 μg/ml and 1 (1.4%) had 16 μg/ml. The mecA gene was detected in 5 (6.8%) isolates but none contained vanA or vanB genes. Both vancomycin-susceptible and intermediate isolates were resistant to multiple antibiotics, while the only vancomycin resistant isolate was resistant to all eight antibiotics. The result confirms the occurrence of phenotypic vancomycin intermediate-resistant S. aureus (VISA) and VRSA infections in Nigeria, but the molecular basis will require further investigation.

Successful treatment of right-sided native valve methicillin-resistant Staphylococcus aureus endocarditis and septicaemia with teicoplanin and rifampicin: A case report

Vancomycin is the drug of choice in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection. However, the presence of certain clinical complications like renal failure alters vancomycin pharmacokinetics, leading to drug accumulation and toxicity. This highlights the need to identify an effective substitute for treating MRSA infections when vancomycin cannot be used. We report the case of a 57-y-old Indian male diagnosed with tricuspid valve endocarditis with septicaemia and a right upper lobe cavity caused by MRSA. The patient also presented with renal failure, which precluded the use of vancomycin for treatment. A 6-week regimen of teicoplanin and rifampicin was used instead, and the infection was successfully treated. This case report provides evidence of the effectiveness of teicoplanin and rifampicin in the treatment of MRSA bacteraemia in situations where the use of vancomycin is contraindicated.

Lack of Increased Colonization with Vancomycin-Resistant Enterococci during Preferential Use of Vancomycin for Treatment during an Outbreak of Healthcare-Associated Clostridium difficile Infection

To assess whether use of oral vancomycin for treatment during an outbreak of Clostridium difficile infection (CDI) was associated with increased rates of colonization with vancomycin-resistant enterococci (VRE). A retrospective analysis of hospital databases. The Jewish General Hospital in Montreal, Quebec, Canada. We collected data regarding VRE colonization and CDI from November 1, 2000, through September 30, 2007, during which policies of preferential oral metronidazole or vancomycin treatment were implemented to control an outbreak of CDI. Four periods were considered: period 1, the preoutbreak period when metronidazole was used; period 2, the CDI outbreak period when metronidazole was used; period 3, the postoutbreak period when vancomycin was used; and period 4, the postoutbreak period when metronidazole was used. A total of 2,412 cases of CDI and 425 cases of VRE colonization were identified. The rate of CDI increased significantly during period 2 and decreased to preoutbreak levels during period 3. The rate of VRE also increased during period 2 and decreased during the first 18 months of period 3. A clonal outbreak of cases of VRE (VanA) colonization was observed toward the end of period 3 and into period 4. Excluding the period of the clonal outbreak, there was a strong correlation between the number of cases of CDI and VRE colonization (r=0.736; P=.001) and a negative association between VRE colonization and vancomycin use (r=-0.765; P=.04). Increased vancomycin use was not associated with an increase in VRE colonization over a 2-year period. Restriction of vancomycin use during CDI outbreaks because of the fear of increasing VRE colonization may not be warranted.

P1819 Heterogeneous vancomycin intermediate resistance within methicillin-resistant Staphylococcus aureus clinical isolates in Alexandria province, Egypt

subpopulations with MIC of vancomycin of > 4 µg/ml at frequency of 1 in 10 6 CFU/ml or higher. Vancomycin MIC values for all isolates were ≤ 4 µg/ml. The clinical outcome of hVISA infection was variable as the hemodialysis patient improved, while death occurred in the two patients from the ICU, and the three diabetic patients underwent variable degrees of amputations. Scanning electron micrographs of vancomycin intermediate resistant subpopulations of hVISA showed enhanced cell wall thickness with evidence of increased extra-cellular material and irregular shape compared to vancomycin susceptible cells. All hVISA isolates were van A gene negative by PCR. It was concluded that this study is an early warning that MRSA strains with full resistance to vancomycin might emerge in Egypt in the future. Due to the increased use of vancomycin for treatment of MRSA infections, screening for hVISA in MRSA strains should be considered as a necessary part of infection control practice emphasizing the importance of a laboratory capability of its identification.

Infective endocarditis.

As compared to the characterization of IE in the 1970s and early 1980s, it appears that IE in the 1990s is more likely to present acutely and in association with fewer classic stigmata and is more likely to be caused by S. aureus. Whether this represents a true clinical and microbiological shift in disease spectrum or is the result of reporting bias is unclear at this time. The ability to clinically designate a case definitely as IE has been improved with utilization of new diagnostic criteria that incorporate findings from two-dimensional echocardiography in the classification schema. These new criteria have been validated in selected patient populations but remain to be validated in other patient groups at risk for IE (e.g., prosthetic-valve recipients). Two-dimensional echocardiography is the noninvasive technique of choice for defining vegetative IE. TEE is significantly more sensitive in identifying valvular vegetations than is TTE, and TEE also is the method of choice for delineating periannular complications of IE. The role of Doppler flow assessment of valvular regurgitation in IE remains to be clarified. Short-course (2-week) regimens of beta-lactam agents plus aminoglycosides appear to be highly effective for the treatment of right-sided IE due to S. aureus. The use of vancomycin for treatment of S. aureus IE remains problematic because of reports of slow response and suboptimal treatment outcomes.

Measurement of serum bactericidal activity and use of vancomycin for treatment of nutritionally variant streptococcal bacteremia

Nutritionally variant streptococci appear more resistant to antimicrobial treatment that other viridans streptococci. We describe a patient with nutritionally variant streptococcal bacteremia who responded to treatment with vancomycin. Results of serum bactericidal tests did not vary in six different media and correlated minimally with the serum concentration of vancomycin.