Spread Of Methicillin-resistant Research Articles

Genetic Characterization of Staphylococcus aureus, Staphylococcus argenteus, and Coagulase-Negative Staphylococci Colonizing Oral Cavity and Hand of Healthy Adults in Northern Japan.

The spread of methicillin resistance and virulence among staphylococci in the community poses a public health concern. In this study, we investigated the prevalence of Staphylococcus species colonizing the oral cavity and hand (skin) of healthy university students and their phenotypic and genetic characteristics in northern Japan. Among a total of 332 subjects, 6 and 110 methicillin-resistant and susceptible Staphylococcus aureus (MRSA and MSSA, respectively) isolates were recovered from 105 subjects. MRSA isolates were genotyped as CC5, CC8, CC45, and CC59 with SCCmec-IIa or IV, among which an isolate of ST6562 (single-locus variant of ST8) harbored SCCmec-IVa, PVL genes and ACME-I, which are the same traits as the USA300 clone. ST1223 S. argenteus was isolated from the oral cavity and hand of a single student. Coagulase-negative Staphylococcus (CoNS) was recovered from 154 subjects (172 isolates), and classified into 17 species, with S. capitis being the most common (38%), followed by S. warneri (24%) and S. epidermidis (15%), including nine mecA-positive isolates. S. capitis was differentiated into seven clusters/subclusters, and genetic factors associated with the NRCS-A clone (nsr, tarJ, ebh) were detected in 10–21% of isolates. The colonization of the USA300-like MRSA variant and S. capitis with the traits of the NRCS-A clone in healthy individuals was noteworthy.

Antibiotic sensitivity analysis of clinical coagulase-negative staphylococci

Background. The increasing role of coagulase-negative staphylococci in the occurrence of staphylococcal infections leads to the need for close attention to them. Special control is required over the sensitivity of bacteria to antibiotics and the spread of methicillin resistance, as a sign of multiple resistance to antibacterial drugs. It is also important to identify the virulence factors of coagulase-negative staphylococci, which determine their behavior in the environment.The aim. To evaluate the sensitivity of strains of coagulase-negative staphylococci to clinically significant antibiotics daptomycin, vancomycin, linezolid and oxacillin and lantibiotic warnerin.Methods. Determination of the minimal inhibitory concentrations of antibacterial compounds for clinical coagulase-negative staphylococci by standard methods of serial dilutions and disc diffusion. Identification of the phenomenon of decreased susceptibility of bacteria to vancomycin by population analysis and concentration gradient. Lipid analysis by thin layer chromatography. Results. High antibacterial activity of vancomycin, daptomycin and linezolid against clinical strains of coagulase-negative staphylococci was shown. The upper limit of the minimum inhibitory concentrations of vancomycin within the sensitive phenotype and the expansion of the ranges of the minimum inhibitory concentrations of daptomycin and warnerin towards an increase in oxacillin-resistant isolates were revealed. The heterogeneous nature of sensitivity to vancomycin of the cultures of the studied strains and the possibility of their rapid enrichment with subpopulations with reduced sensitivity to this antibiotic have been established. The selection of resistance of coagulase-negative staphylococci to vancomycin was accompanied by an increase in the synthesis of lysylphosphatidylglycerol and a decrease in their sensitivity to cationic peptide compounds.Conclusion. The revealed prevalence of the methicillin-resistant phenotype of clinical strains of coagulase-negative staphylococci, along with the presence in the lipid spectrum of the universal factor of resistance to cationic antibacterial compounds, lysylphosphatidylglycerol, entails the need for new methodological solutions for diagnosing infections caused by coagulase-negative staphylococci.

MRSA colonization in health care professionals with varying degrees of exposure to the hospital environment and its susceptibility to mupirocin in a tertiary care centre

Methicillin-resistant (MRSA) is one of the major causes of healthcare associated infections with significant morbidity and mortality. Health care workers act as a carrier in spread of MRSA in hospitals. Use of Mupirocin to eradicate the carrier state is the need of the hour.: This study was undertaken to assess the prevalence of MRSA colonization among health care workers with varying degree of exposure to hospital environment and to know the susceptibility of Mupirocin to MRSA. : Swabs were collected from anterior nares and finger web spaces of 100 health care workers (HCWs). The specimens were processed and colonies of were identified by standard methods. The strains of MRSA were identified by using Cefoxitin (30µg) disk on Muller Hinton agar. The MRSA isolates were then tested for Mupirocin susceptibility.In the present study, 100 nasal and inter digital spaces swabs yielded 15 and 10 MRSA strains respectively. Among the 100 HCWs screened, the majority of MRSA colonization was seen in HCWs with a history of exposure to hospital environment for around 5-10 years or more. All 30 with 15 MRSA strains isolated was sensitive to both 5µg and 200µg Mupirocin disc by Kirby-Bauer disc diffusion method.The high rate of Nasal MRSA carriage among health care workers is alarming. HCWs with long duration of exposure to hospital environment were more colonized with MRSA. More awareness and training sessions on the importance of MRSA and hand hygiene measures to be implemented to prevent MRSA transmission from HCWs to vulnerable patients. We suggest that MRSA screening should be performed for all HCWs and detection of susceptibility of Mupirocin will result in appropriate use of this antibiotic in decolonization.

Multidrug-resistant Staphylococcus spp and its impact on patient outcome.

In order to analyze the outcomes, clinical features, and resistance of Staphylococcus spp infections, a prospective cohort study was conducted at a 234-bed, tertiary care teaching hospital. Multidrug-resistant (MDR) infections were associated with increased mortality and length of hospital stay (LOS), whereas methicillin resistance (MRS) was correlated with prolonged LOS after infection. These data highlight the importance of infection control and antibiotic stewardship to prevent the emergence and spread of MRS and MDR health care-associated infections.

Can We Prevent Transmission of Drug-Resistant Bacteria in Hospitals?

How to limit the spread of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) in the healthcare environment

Possible usefulness of cephem antibiotics with anti-staphylococcal activity for preventing the spread of methicillin-resistant Staphylococcus aureus.

The validity of clinical use of cephem antibiotics for preventing the spread of methicillin-resistant Staphylococcus aureus (MRSA) was investigated using a methicillin-susceptible S. aureus (MSSA) carrying mecA gene. It became evident that drug with anti-staphylococcal activity, such as cefuzonam (CZON) or cefazolin (CEZ), has comparatively low selectivity of high-level methicillin resistant clones (methicillin MIC range from 25 to 800 micrograms/ml) from MSSA carrying mecA gene among cephem antibiotics tested. At concentrations over 1.56 micrograms/ml of both CZON and CEZ, about a 2-3 log10 decrease in viable count was observed. Therefore, it seems that much satisfactory disappearance of bacterial cells can be obtained in cooperation with host defence mechanisms.