Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and its antibiotic susceptibility pattern in healthcare workers at Namazi Hospital, Shiraz, Iran.
ABSTRACT The aim of this study was to determine the prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers (HCWs) at Namazi Hospital, Shiraz, Iran.
This cross-sectional study was conducted from July to November 2006. Nasal swabs were taken from 600 randomly selected HCWs. The isolates were identified as S. aureus based on morphology, Gram stain, catalase test, coagulase test, and mannitol salt agar fermentation. To analyze sensitivity patterns of MRSA strains more precisely, minimum inhibitory concentrations (MICs) of antibiotics were determined by the E-test method. All methicillin-resistant isolates were examined for the existence of the mecA gene by total DNA extraction and PCR.
The prevalence of nasal carriage of methicillin-sensitive S. aureus (MSSA) was 25.7% and of MRSA was 5.3%, with the highest nasal carriage of MRSA in surgical wards and the emergency department. There was no significant difference between the sexes (p=0.247), age (p=0.817), and years of healthcare service (p=0.15) with regard to the nasal carriage of MRSA and MSSA. In the univariate analysis, a statistically significant difference was only found for occupation (p=0.032) between the carriage of MSSA and MRSA. In the multivariate analysis, the occupation 'nurse' was independently associated with MRSA carriage (p=0.012, odds ratio 3.6, 95% confidence interval 1.3-9.7). The highest resistance rate for both gentamicin and clindamycin (69%) was noted among the MRSA strains. None of the MRSA strains were resistant to mupirocin, linezolid, fusidic acid, or vancomycin. The existence of the mecA gene in all 32 methicillin-resistant isolates was observed by PCR.
This study revealed the prevalence of nasal carriage of S. aureus strains among HCWs to be lower than that found in other studies from Iran. The antibiotic susceptibility patterns also differed, perhaps as a result of the excessive use of antibiotics at our hospital. Only the occupation of nurse was an independent risk factor for MRSA carriage.
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ABSTRACT: Surveillance of bacteraemia caused by methicillin-resistant Staphylococcus aureus (MRSA) in the UK has involved collection of data from hospital microbiology laboratories via several mechanisms, including a voluntary reporting scheme that has been operational in England and Wales since 1989 and mandatory reporting schemes that have been running independently in England, Wales, Scotland and Northern Ireland since 2001. In addition, surveillance schemes involving panels of participating sentinel laboratories that submit isolates for centralized susceptibility testing, such as the Bacteraemia Resistance Surveillance Programme run by the BSAC, have also been established. Each of these data sources have particular advantages, but they also have their individual limitations, with the result that they each give an incomplete picture if considered in isolation. However, by pooling the findings from these different but complementary surveillance programmes, a much more comprehensive and credible picture of the problem posed by MRSA is produced. These schemes have shown both a dramatic rise in the total numbers of cases of S. aureus bacteraemia reported annually and an increase in the proportion of such cases that involve MRSA (from 2% in 1990 to >40% in the early 2000s), although the most recent data indicate a slight reversal of these trends. Characterization of isolates of MRSA shows a marked temporal relationship between the rise in MRSA bacteraemias and the emergence and spread of two strains of epidemic MRSA, EMRSA-15 and EMRSA-16. Surveillance and control of MRSA infection continue to be high profile and further developments to the mandatory surveillance system in England are likely in the near future.Journal of Antimicrobial Chemotherapy 09/2005; 56(3):455-62. · 5.34 Impact Factor
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ABSTRACT: Methicillin resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen that causes severe morbidity and mortality worldwide. MRSA strains are endemic in many American and European hospitals and account for 29%-35% of all clinical isolates. Recent studies have documented the increased costs associated with MRSA infection, as well as the importance of colonisation pressure. Surveillance strategies have been proposed especially in high risk areas such as the intensive care unit. Pneumonia and bacteraemia account for the majority of MRSA serious clinical infections, but intra-abdominal infections, osteomyelitis, toxic shock syndrome, food poisoning, and deep tissue infections are also important clinical diseases. The traditional antibiotic therapy for MRSA is a glycopeptide, vancomycin. New antibiotics have been recently released that add to the armamentarium for therapy against MRSA and include linezolid, and quinupristin/dalfopristin, but cost, side effects, and resistance may limit their long term usefulness.Postgraduate Medical Journal 08/2002; 78(921):385-92. · 1.61 Impact Factor
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ABSTRACT: The purpose of undertaking susceptibility testing, by whatever method, is to attempt to integrate the susceptibility of a population of potential pathogens with the pharmacokinetics of the antimicrobial and, whenever possible, to review this relationship in the light of clinical experience following therapy in clinical trials. Breakpoints are discriminatory antimicrobial concentrations used in the interpretation of results of susceptibility testing to define isolates as susceptible, intermediate or resistant. Clinical, pharmacological and microbiological considerations are important in setting breakpoints, and the ideal mix of these factors is unknown. Different countries have different approaches to this problem but, by and large, these approaches have much in common. This paper attempts to summarize the philosophy of the British Society for Antimicrobial Chemotherapy (BSAC) Working Party in its approach to setting breakpoints and to update the activities of the Working Party since it initially published breakpoints, approximately 10 years ago. The formula outlined by the BSAC Working Party in 1991 has been used to set the breakpoints presented here. The Working Party accepts that in the light of new knowledge, there is a need to reassess how breakpoints are defined, and this paper also summarizes the future activities of the Working Party.Journal of Antimicrobial Chemotherapy 08/2001; 48 Suppl 1:17-28. · 5.34 Impact Factor