First detected isolate of glycopeptide-intermediate resistant Staphylococcus aureus in a renal unit at a central academic hospital in KwaZulu-Natal: brief report (original) (raw)
Staphylococcus aureus with reduced susceptibility to vancomycin
Ceylon Medical Journal, 2011
Staphylococcus aureus with Reduced Susceptibility to Vancomycin-Illinois, 1999 Staphylococcus aureus is one of the most common causes of hospital-and community-acquired infections. Nosocomial methicillin-resistant S. aureus (MRSA) infections have become common, and cases of community-acquired MRSA infections also have occurred (1,2). Since 1996, vancomycin-intermediate S. aureus (VISA; vancomycin minimum inhibitory concentration [MIC]=8-16 µg/mL) has been identified in Europe, Asia, and the United States (3-5). The emergence of reduced vancomycin susceptibility in S. aureus increases the possibility that some strains will become fully resistant and that available antimicrobial agents will become ineffective for treating infections caused by such strains. This report describes the fourth case of confirmed VISA from a patient in the United States. In April 1999, a 63-year-old woman with MRSA bacteremia (MIC <1 µg/mL) was transferred from a long-term-care facility to an Illinois hospital (hospital A). The patient had a history of frequent hospitalizations for complications of hemodialysis-dependent, end-stage renal disease, and intravascular access, including two failed arteriovenous grafts, multiple central venous catheter-associated infections, and intermittent receipt of vancomycin therapy through June 1998. Thirteen days after hospital admission and 25 days after initiating vancomycin therapy (median vancomycin serum con-centration=12.7 µg/mL; range: 12.1 µg/mL-20.9 µg/mL), a culture from her blood grew S. aureus with an MIC of 4 µg/mL; the blood culture was tested using the Vitek ® system (bioMérieux; Hazelwood, Missouri)*. Three subsequent blood specimens drawn within the next 3 days grew S. aureus with MICs of 8 µg/mL on confirmatory testing. The isolates, identical by pulsed-field gel electrophoresis, were resistant to penicillin, oxacillin, clindamycin, erythromycin, ciprofloxacin, and rifampin but susceptible to trimethoprim-sulfamethoxazole, tetracycline, gentamicin, and had intermediate susceptibility to chloramphenicol. No VISA strains were recovered from other body sites. An echocardiogram demonstrated a mitral valve vegetation but the patient declined surgical intervention. Despite treatment with intravenous vancomycin, rifampin, and *Use of trade names and commercial sources is for identification only and does not imply endorsement by CDC or the U.S. Department of Health and Human Services.
Healthcare Infection, 2000
There have been several reported cases to date of Staphylococcus aureus (S. aureus) with decreased susceptibility to the glycopeptide antibiotics, particularly vancomycin. Such isolates have been termed VISA (vancomycin-intermediate S. aureus) or GISA (glycopeptide-intermediate S. aureus). These strains have developed in patients with pre-existing methicillin-resistant S. aureus (MRSA) infections treated with prolonged courses of the drug of choice, vancomycin. Resistance to vancomycin severely limits treatment options for these patients, highlighting the need to preserve the utility of the drug through restricted usage and the need for increased awareness of infection control measures to prevent acquisition of MRSA in the first instance. While vancomycin-resistant Enterococcus (VRE) has received significant attention in the scientific literature and the media, the clinical implications of a vancomycin-resistant strain of S. aureus, a more pathogenic and virulent organism, are far more significant. This review details the clinical features and microbiology of the isolates found so far, the use of vancomycin in staphylococcal infections and some of the measures necessary to prevent the development and spread of vancomycin resistance in Australia.
Vancomycin Resistant Staphylococcus Aureus (Vrsa)
Background: Vancomycin resistant Staphylococcus aureus (VRSA) are serious strains of Staphylococci that are difficult to be treated and have considerable emerging percentage in the world. Objectives: To estimate the percentage of VRSA in Khartoum state. Method:The different specimens were randomly collected from different patients suffering from various clinical manifestations after accepting the informed consents and cultured in number of different culture media according to each sample, then sensitivity testing is done using oxacillin(1 mcg), vancomycin(30 mcg) ,amoxyclav(30 mcg) ,erythromycin(15 mcg), clindamycin(2 mcg) and amikacin (30 mcg)discs and interpreted according to Kirby Bauer reference procedure. Results: According to the outcome of our study, S.aureus that were resistant to vancomycin disc (30 mcg) represents 12% from total 100 S.aureus positive specimens and 3.7% from MRSA group while 15.1% from MSSA group. On the other hand clindamycin resistance represents about 10% ,Inducible clindamycin resistance forming D shape appearance 76.1% while 23.8% showed constitutive resistance. There is a great resistance of S.aureus bacteria to amoxyclav disc(30 mcg (20/10 mcg)) with percentage of 76% while 24% nly were sensitive to the disc. Conclusion: There is a significant percentage of S.aureus bacteria that showed resistance to vancomycin.
Journal of Clinical Microbiology, 2010
Strain D958, a methicillin-resistant Staphylococcus aureus strain with reduced susceptibility to vancomycin, was isolated from a 69-year-old Saudi male patient presenting with severe sepsis immediately after admission. Despite high serum levels of vancomycin, the same S. aureus strain was isolated from five blood culture sets during 1 week. Treatment failure under therapeutic levels of vancomycin prompted us to investigate the resistance profile of this strain in further detail. The MIC values for vancomycin as determined by Etest and microdilution were 3.0 and 2.0 mg/liter, respectively, and remained unchanged during the treatment course. The macro-Etest method showed a MIC of 4 mg/liter. The strain showed liquid vancomycin and lysostaphin MBCs of 2.0 and 5.0 mg/liter, respectively. The isolates were confirmed as heterogeneously vancomycinintermediate S. aureus (hVISA) by vancomycin population analysis profile. The areas under these curves were similar for Mu3 and D958 for vancomycin and teicoplanin (ratio values were 1 and 1.1 for vancomycin and teicoplanin, respectively). Extensive genotyping and molecular characterization demonstrated that the strain harbored a staphylococcal cassette chromosome mec element (SCCmec) type III cassette and was of sequence type ST241, a single-locus variant of the successful multiresistant clone ST239. Microarray results demonstrated that D958 contained numerous resistance determinants (generally plasmid or phage encoded). These results suggest that this strain is constitutively expressing an altered susceptibility to vancomycin. Further studies are warranted to assess the clonal distribution of such strains displaying reduced susceptibility to vancomycin prior to any antimicrobial therapy. Staphylococcus aureus is a major cause of serious hospitaland community-acquired infections associated with morbidity and mortality (42). In recent years, prevalence rates of methicillin-resistant S. aureus (MRSA) strains have varied between (and within) countries, but they have increased significantly since the early 1990s. In the first decade of the new millennium, MRSA rates have reached worrisome levels in numerous countries, such as the United Kingdom (40%), France and Greece (35%), and Italy (45%) (53). Simultaneously, the United Kingdom, Ireland, and Greece have reported some of the highest rates of MRSA from bloodstream isolates (44, 41, and 44%, respectively, in 2004) (15). In 1996, the first clinical strain of S. aureus with reduced susceptibility to vancomycin (MIC of 8.0 mg/liter) was reported in Japan (25). In 2002, the first two clinical infections caused by vancomycin-resistant S. aureus strains (VRSA) were confirmed in the United States (10, 38). The latter report describes the first documented case of an infection caused by VRSA (vancomycin MIC, Ն32 mg/ liter) resulting from the transfer of a vanA gene from Enterococcus faecalis to S. aureus. Although the emergence of vancomycin-intermediate S. aureus (VISA, or GISA for glycopeptide-intermediate S. aureus) (21, 23
Vancomycin‐ResistantStaphylococcus aureusin the Absence of Vancomycin Exposure
Clinical Infectious Diseases, 2004
We report findings from our investigation of the world's second clinical isolate of vancomycin-resistant Staphylococcus aureus (VRSA). An elderly man was hospitalized with an infected chronic heel ulcer and osteomyelitis. Before hospital admission, he received multiple courses of antibiotic therapy but, notably, no vancomycin. Numerous cultures of ulcer specimens (performed on an outpatient basis) grew methicillinresistant, vancomycin-susceptible S. aureus and vancomycin-resistant Enterococcus species. At admission, an additional culture of a specimen from the heel ulcer grew S. aureus that was identified as VRSA (minimal inhibitory concentration for vancomycin [by broth-microdilution], 32 mg/mL). Further evaluation confirmed the presence of the vanA gene mediating vancomycin resistance. To assess VRSA transmission, we performed a carriage study of 283 identified contacts and an environmental survey of the patient's home; no VRSA isolates were recovered. This case illustrates that recent exposure by patients to vancomycin is not necessary for development of vanA-containing VRSA. For clinical and public health reasons, it is essential that microbiology laboratories adequately test for vancomycin-resistance in S. aureus. Staphylococcus aureus is one of the most common causes of serious infection in community and hospital settings [1, 2]. Methicillin-resistant S. aureus (MRSA) is now endemic in health care facilities, with rates of 150% in some health care settings [3]. Also, recent reports describe MRSA carriage in persons in the community who do not have health care-associated risks [4]. The increased incidence of MRSA has led to more frequent use of vancomycin, the drug commonly relied on for treating MRSA infections.
Methicillin and vancomycin resistant S. aureus in hospitalized patients
Journal of Global Infectious Diseases, 2010
S. aureus is the major bacterial cause of skin, soft tissue and bone infections, and one of the commonest causes of healthcareassociated bacteremia. Hospital-associated methicillin-resistant S. aureus (MRSA) carriage is associated with an increased risk of infection, morbidity and mortality. Screening of high-risk patients at the time of hospital admission and decolonization has proved to be an important factor in an effort to reduce nosocomial transmission. The electronic database Pub Med was searched for all the articles on "Establishment of MRSA and the emergence of vancomycin-resistant S. aureus (VRSA)." The search included case reports, case series and reviews. All the articles were cross-referenced to search for any more available articles. A total of 88 references were obtained. The studies showed a steady increase in the number of vancomycin-intermediate and vancomycinresistant S. aureus. Extensive use of vancomycin creates a selective pressure that favors the outgrowth of rare, vancomycin-resistant clones leading to heterogenous vancomycin intermediate S. aureus hVISA clones, and eventually, with continued exposure, to a uniform population of vancomycin-intermediate S. aureus (VISA) clones. However, the criteria for identifying hVISA strains have not been standardized, complicating any determination of their clinical significance and role in treatment failures. The spread of MRSA from the hospital to the community, coupled with the emergence of VISA and VRSA, has become major concern among healthcare providers. Infection-control measures, reliable laboratory screening for resistance, appropriate antibiotic prescribing practices and avoidance of blanket treatment can prevent long-term emergence of resistance.
Relevance of vancomycin susceptibility on patients outcome infected with Staphylococcus aureus
Pharmacotherapy, 2019
Background: Staphylococcus aureus is a serious pathogen with high rates of complications. We aim to study the susceptibility and outcome of S. aureus infection. Methods: A retrospective multicentre study conducted in three hospitals, Amman-Jordan. Between June 2013 and March 2014 laboratory records were reviewed for culture-positive samples growing S. aureus, also, medical records for the patients were reviewed for the demographic data, predisposing conditions, vancomycin MIC level, and outcome. Inpatients and outpatients were included, a case was classified as either hospital-associated (HA), community-associated (CA), or healthcare-associated (HCA). Data were entered as excel sheets and were statistically analyzed using SPSS version 21. Results: A total of 127 patient (46% MRSA) were culture-positive for S. aureus collected from different sources. Of these, eighty (63%) were inpatients. High resistance rates to non-β-lactam antimicrobials were recorded. Glycopeptides agents were the antibiotics of choice for the treatment of infections caused by MRSA strains. Complications rates were higher in patients with MRSA infections including mortality, whereas hospital stay was longer for patients infected with MSSA. Conclusion: Infection rates with MRSA were high among patients. There is a value for knowing vancomycin MICs for treatment of S. aureus and its implication for patients outcomes, though most outcomes were significantly worse due to MRSA infection.
Journal of clinical …, 1999
Isolates of Staphylococcus aureus with decreased susceptibilities to glycopeptide antimicrobial agents, such as vancomycin and teicoplanin, have emerged in the United States and elsewhere. Commercially prepared brain heart infusion agar (BHIA) supplemented with 6 g of vancomycin per ml was shown in a previous study to detect glycopeptide-intermediate S. aureus (GISA) with high sensitivity and specificity; however, this medium, when prepared in-house, occasionally showed growth of vancomycin-susceptible control organisms. This limitation could significantly impact laboratories that prepare media in-house, particularly if they wished to conduct large surveillance studies for GISA. Therefore, a pilot study to detect GISA was performed with vancomycin-containing Mueller-Hinton agar (MHA) prepared in-house in place of commercially prepared BHIA. MHA was selected for this study because this medium is widely available and well standardized. The results of the pilot study showed that supplementation of MHA with 5 g of vancomycin per ml was both a sensitive and a specific method for screening for GISA isolates. This method was used to screen for GISA among 630 clinical isolates of methicillin-resistant S. aureus collected during 1997 from 33 U.S. hospitals. Although 14 S. aureus isolates grew on the screening agar, all were vancomycin susceptible (MICs were <1 g/ml) by broth microdilution testing. Population analyses of five isolates revealed two with a subpopulation for which vancomycin MICs were 8 g/ml. In summary, the MHA screen plate containing 5 g of vancomycin per ml prepared in-house provides a sensitive and cost-effective method for large-scale screening for GISA for which vancomycin MICs are 8 g/ml. However, confirmation of isolates as vancomycin resistant is critical. This study suggests that GISA was not a widespread problem in the United States in 1997.
Journal of the Medical Association of Thailand = Chotmaihet thangphaet, 2014
Staphylococcus aureus is a species of bacteria that causes a number of diseases and more than 60% of it is presently resistant to methicillin. Vancomycin is the drug of choice for the eradication of methicillin-resistant S. aureus (MRSA). This study aimed to investigate the susceptibility of heterogeneous vancomycin intermediate S. aureus (hVISA) and vancomycin intermediate S. aureus (VISA) to vancomycin by standard disk diffusion, microbroth dilution, a one-point population assay, and a population analysis profile. Sixty-eight MRSA isolates from patients admitted to Sanprasitthiprasong Hospital between November 2010 and November 2011 were tested. Standard disk diffusion showed that all the MRSA isolates were susceptible to vancomycin. Vancomycin MICs for all isolates were 1-2 microg/mL. Only two MRSA isolates (2.9%) were able to grow on brain heart infusion agar supplemented with vancomycin 4 microg/mL and were confirmed by a population analysis as hVISA. This study showed the effe...
American Journal of Infectious Diseases, 2013
Multidrug resistant Methicillin-Resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections and is on the rise. The aim of this investigation was to explore the prevalence of MRSA and heterogeneous Glycopeptide Intermediate Staphylococcus aureus (hGISA) in various clinical samples, to investigate the various antibiotic resistant determinant genes among these strains collected from north and west Indian hospitals and to evaluate the response of various drugs to these strains. A total of 413 clinical specimens collected from different hospitals were processed for the screening of S. aureus and MRSA. All the MRSA strains were further screened for hGISA on Mueller-Hinton agar containing 8 µg mL −1 teicoplanin or 6 µg mL −1 vancomycin. hGISA confirmed by the E-test method with a dense inoculum and a simplified method of population analysis. Susceptibility study was conducted according to the Clinical and Laboratory Standards Institute (CLSI) methods. Among 211/413 S. aureus clinical isolates, 61.6% (130/211) of the isolates were confirmed to be MRSA which included maximum isolates from pus, blood, urine, wound swab and ear swab samples in decreasing order. hGISA strains were found in 8/130 (6.1%) isolates. Vancoplus, a novel antibiotic adjuvant entity was found to be susceptible in 96.1 to 97.8% MRSA strains and showed intermediate response in 2.2 to 3.8% of isolates. Linezolid appeared to be second most active antibiotic with 48.0 to 81.2% susceptibility, followed by teicoplanin (41.3 to 56.2% susceptibility). There was 8.7 to 9.6% resistance observed in Linezolid which was increased to 48% in teicoplanin, to >60% in daptomycin and >75% in vancomycin. Interestingly, none of the isolates were susceptible to ceftriaxone and cefoperazone plus sulbactam. From the above study it can be concluded that prevelance of MRSA has reached a significant level and Vancoplus is the most effective drug in MRSA as well as hGISA organisms in comparison to comparator drugs.
Journal of Laboratory Physicians
PURPOSE: We aimed to determine the recent pattern of antibiotic resistance and assess the vancomycin susceptibility profile of clinical Staphylococcus aureus in view of emerging reports of vancomycin creep, reduced vancomycin susceptibility (RVS), including heterogeneous vancomycin-intermediate S. aureus (hVISA) and vancomycin-intermediate S. aureus, and vancomycin resistance in S. aureus isolates. MATERIALS AND METHODS: Consecutive, nonduplicate isolates of S. aureus between July 2015 and June 2016 were subjected to antimicrobial susceptibility testing using standard disk diffusion test or Etest as per the Clinical and Laboratory Standards Institute 2015. Detection of hVISA was done by glycopeptide resistance detection Etest according to the manufacturer's instructions in strains with vancomycin minimum inhibitory concentration of 1-2 µg/ml. RESULTS: A total of 284 S. aureus were obtained from pus (175, 61.6%), respiratory tract (31, 10.9%), urine (27, 9.5%), blood (25, 8.8%), body fluids (18, 6.3%), and catheter tips (8, 2.8%). 127 (44.7%) isolates were methicillin resistant, and 158 (55.6%) were multidrug resistant. High resistance was observed to penicillin (81.7%), erythromycin (62.3%), and ciprofloxacin (52.1%), whereas the resistance was low to gentamicin (5.3%), rifampicin (8.1%), and doxycycline (9.5%). Two hundred and fifty-one (88.3%) isolates were fully susceptible to vancomycin, whereas 33 (11.6%) demonstrated RVS. All were uniformly susceptible to linezolid, tigecycline, and daptomycin. CONCLUSIONS: A moderately high percentage of S. aureus isolates demonstrated RVS, which may limit its usefulness in methicillin-resistant isolates and may be associated with increased complications in methicillin-susceptible infections. In view of increasing glycopeptide resistance, the susceptibility status of vancomycin along with other antibiotics among clinical S. aureus isolates should be investigated periodically.
Multidrug resistant Methicillin-Resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections and is on the rise. The aim of this investigation was to explore the prevalence of MRSA and heterogeneous Glycopeptide Intermediate Staphylococcus aureus (hGISA) in various clinical samples, to investigate the various antibiotic resistant determinant genes among these strains collected from north and west Indian hospitals and to evaluate the response of various drugs to these strains. A total of 413 clinical specimens collected from different hospitals were processed for the screening of S. aureus and MRSA. All the MRSA strains were further screened for hGISA on Mueller-Hinton agar containing 8 µg mL −1 teicoplanin or 6 µg mL −1 vancomycin. hGISA confirmed by the E-test method with a dense inoculum and a simplified method of population analysis. Susceptibility study was conducted according to the Clinical and Laboratory Standards Institute (CLSI) methods. Among 211/413 S. aureus clinical isolates, 61.6% (130/211) of the isolates were confirmed to be MRSA which included maximum isolates from pus, blood, urine, wound swab and ear swab samples in decreasing order. hGISA strains were found in 8/130 (6.1%) isolates. Vancoplus, a novel antibiotic adjuvant entity was found to be susceptible in 96.1 to 97.8% MRSA strains and showed intermediate response in 2.2 to 3.8% of isolates. Linezolid appeared to be second most active antibiotic with 48.0 to 81.2% susceptibility, followed by teicoplanin (41.3 to 56.2% susceptibility). There was 8.7 to 9.6% resistance observed in Linezolid which was increased to 48% in teicoplanin, to >60% in daptomycin and >75% in vancomycin. Interestingly, none of the isolates were susceptible to ceftriaxone and cefoperazone plus sulbactam. From the above study it can be concluded that prevelance of MRSA has reached a significant level and Vancoplus is the most effective drug in MRSA as well as hGISA organisms in comparison to comparator drugs.
Brazilian Journal of Infectious Diseases, 2003
We describe a case of clinical failure of vancomycin treatment of Staphylococcus aureus infection and the laboratory characteristics of the organism in a tertiary referral university hospital in southern Brazil. An 11-month-old male patient presented with pneumonia and S. aureus was isolated from his respiratory tract. Initial treatment with oxacillin and gentamicin was ineffective. Vancomycin was added to the regimen as the patient worsened, but after the 30 th day of vancomycin treatment S. aureus was isolated from the blood. This isolate had a minimum inhibitory concentration (MIC) for vancomycin of 4 µ µ µ µ µg/mL. After pre-incubation with vancomycin the isolate displayed an increase in the expression of vancomycin resistance and colonies grew in the presence of up to 12 µ µ µ µ µg/mL vancomycin. Based on these results, and considering that the patient had not responded to vancomycin, the isolate was considered to be S. aureus heteroresistant to vancomycin (SAHV). The SAHV proved to be similar, based on DNA macrorestriction analysis, to methicillin resistant S. aureus (MRSA) isolates from other patients in the hospital who had responded to vancomycin treatment. Our findings underline the need to improve methods in the clinical laboratory to detect the emergence of S. aureus clinically resistant to vancomycin . The fact that the isolate emerged in the blood 30 days after vancomycin treatment was initiated suggests that the organism was originally an MRSA that had acquired the ability to circumvent the mechanism of action of vancomycin.
African Journal of Microbiology Research, 2012
Staphylococcus aureus. The reports of the emergence of vancomycin intermediate and vancomycin resistant S. aureus from various parts of the world have been of great clinical concern. This study was performed to monitor the status of glycopeptide susceptibility against methicillin resistant S. aureus in our set up. All non-duplicate methicillin resistant Staphylococcus aureus (MRSA) isolates recovered during the period of study from various wards of Military Hospital Rawalpindi and PAEC General Hospital Islamabad, were subjected to the detection of minimum inhibitory concentrations of vancomycin using E-strips. Results were analyzed to evaluate the possible presence of vancomycin intermediate and resistant strains in the set up. A total of 276 methicillin-resistant S. aureus isolates were studied. The range of vancomycin minimum inhibitory concentrations (MIC) was 0.19 to 3 ug/mL. MIC 50 came out to be 0.75 ug/mL whereas the MIC 90 was 1.5 ug/ mL. 128 out of 276 (46%) isolates had vancomycin MIC equal to or greater than 1 ug/mL. Majority of the isolates (69%) were from pus samples. No vancomycin resistant or intermediate strain of MRSA was isolated during the study but there were a significant number of isolates having ≥ 1 µg/ml MIC of vancomycin.