Incidence Of Methicillin Resistance Research Articles

Determining the enterotoxin genes and methicillin resistance in Staphylococcus Aureus isolated from goat milk and its products

Milk and its products can be frequently contaminated with enterotoxigenic and methicillin-resistant S. aureus, and in such a case, it causes various diseases, especially staphylococcal food poisoning. In the present study, 100 sample materials (50 goat milk, 25 goat cream, and 25 goat cheese) were collected from 65 livestock farms in Erzurum. All samples were analyzed and tested selectively according to the EN ISO 6888-1 procedure standard. The obtained isolates were examined with the PCR in terms of nuc, Panton-Valentine Leukocidin (PVL), mecA, and enterotoxin genes. S. aureus was detected in 4 of 50 (8%) milk samples, 2 of 25 (8%) cream samples, 3 of 25 (12%) cheese samples, and 9 of the total samples (9%). While the incidence of methicillin resistance was found to be 3% by the disc diffusion method, the incidence of the mecA gene was found to be 2% by PCR. In terms of enterotoxin genes, 8% (4/50) of milk samples, 12% (3/25) of cheese samples, and 8% (2/25) of cream samples contained at least one enterotoxin gene. In total, 9% of 100 samples contained enterotoxigenic S. aureus. In conclusion, the consumption of enterotoxigenic and mecA positive S. aureus-containing raw milk, dairy products that have not been adequately heat-treated, or milk and products that are not kept in proper storage conditions pose a danger to public health.

Effect of Antibiotic Exposure on Upper Respiratory Tract Bacterial Flora.

BackgroundThe human microbiota modulates the immune system and forms the surface flora. Antibiotic administration causes dysbiosis in the intestinal flora. It is not clear if antibiotic administration in the community effects the upper airway flora in the mid-term or long-term. This study aims to define long-term influence of antibiotics on upper airway flora.Material/MethodsIn this prospective study, aerobic microbiological analysis of nasal and nasopharyngeal surfaces was performed. Antibiotic administration history of the last 6 months was retrieved using the social insurance database. Culture results of antibiotic-treated and antibiotic-naïve subjects were compared by Pearson’s chi-square test or Fisher’s exact test.ResultsA total of 210 subjects were included in the study. Normal flora were documented in 86 nasal swabs and 99 nasopharyngeal swabs. Most of the remaining cases demonstrated gram-positive bacterial overgrowth. There were 113 subjects who did not receive any antibiotic, and 93% of the remaining 97 patients received broad-spectrum antibiotics. Statistical analysis showed that nasal and nasopharyngeal flora did not change upon antibiotic administration, but antibiotic administration during the last month caused increased methicillin resistance development of coagulase-negative Staphylococcus and Staphylococcus aureus microorganisms.ConclusionsAntibiotic exposure did not lead to perturbations in general composition of upper airway flora within 6 months, although the incidence of methicillin resistance in coagulase-positive and -negative Staphylococci demonstrated significant increases when patients received antibiotic during the last month. This should be considered in case of broad-spectrum antibiotic administration, since methicillin resistance increases the morbidity and mortality of nosocomial Staphylococcus infections.

Right-sided infectious endocarditis in patients with cardiac devices: Clinical profile and prognosis in Hospital University Ibn Rochd Casablanca

Due to numerous indications relating to device implants and the aging of the population, the epidemiology of infective endocarditis on the right side has radically changed and is now one of the main groups affected.The aim of this work is to describe the epidemiology, clinical profile and outcomes of right-sided infectious endocarditis in people with cardiac devices. We included the final episodes of infectious endocarditis diagnosed in the cardiology department of CHU IBN Rochd Casablanca. A retrospective analysis of 81 variables, a follow-up analysis and a univariate analysis of hospital mortality was performed. Out of 112 episodes, 13 people with cardiac devices presented with right-sided infectious endocarditis (11.6%). The mean age ± was 28 years. Staphylococcus were the main microorganisms responsible (coagulase negative 37%, aureus 25%) and 40% resistant to methicillin. Surgery was performed in 42% of the patients. Mortality in the hospital was 7.6%. A univariate analysis showed that 38% had renal failure on admission, 7.6% had septic shock and 15.4% had persistent infection during clinical course; which increased hospital mortality while resuming surgery is a protective factor. Infectious endocarditis of the right heart has a low mortality in hospital. Coagulase-negative staphylococci are responsible for almost half of the episodes and the incidence of methicillin resistance is high. The removal of the device is mandatory because it reduces mortality in the hospital.

DMolecular detection of methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase-negative Staphylococcus (CoNS) in Iran

The incidence of methicillin resistance has risen among nosocomial isolates ofStaphylococcus aureus and coagulase negative staphylococci. The present study was carried out to investigate the prevalence of methicillin-resistant Staphylococcus aureus(MRSA) and methicillin-resistant coagulase negative staphylococci (MRCoNS) and to determine their antibiotic susceptibility pattern. A total of one hundred and thirty clinical staphylococcal isolates recovered from blood, tracheal aspirate, urine and wound specimens were evaluated for susceptibility to penicillin, amikacin, ciprofloxacin, vancomycin, erythromycin, ceftriaxone, methicillin, rifampin and gentamicin by Disk diffusion method and molecular detection of mecA gene. The results showed that MRCoNS were more resistant to these antibiotics as compared to MRSA and the most effective antibiotic to use for staphylocoocal isolates is vancomycin showing (100% of S. aureus and 90% of CoNS) efficacy. The mecA gene was detected in 56% of the isolatedS. aureus and 70% of the CONS isolates. The prevalence of methicillin resistant staphylococci in Iran was very high and 45.4% of MRSA and MRCoNS isolates were at least resistance to 3 or more classes of antibiotics. The high prevalence of MRSA immerged in Iran could be originated due to antibiotic pressure and poor control measures on the application of antibiotics such as methicillin. Key words: Staphylococcus aureus (S. aureus), coagulase-negative staphylococci (CoNS), mecA gene, methicillin-resistance

Prevalence, aetiology and antibiotic resistance profiles of coagulase negative staphylococci isolated in a teaching hospital.

In this paper we carried out a study about prevalence of the clinically significant coagulase negative staphylococcal (CNS) isolates found in an university hospital. Two hundred four CNS isolates from 191 patients obtained between the period of 1998 to 2002, were studied. About 27% (52/191) of the infection cases studied were confirmed as CNS-associated diseases. Blood stream infection (BSI) was the most frequent CNS associated-disease (25%; 13/52). The great majority of the BSI was verified in the Neonatal Intensive Care Unit (NICU). The analysis of the 52 patients medical history showed that 85% of the BSI was acquired in hospital. Most of the CNS nosocomial infections were associated with the use of indwelling medical devices. The incidence of methicillin-resistance among significant CNS isolates was 38%. In this study, a high percentage of exogenous contaminant was verified (60%), indicating that contamination of clinical specimens during sample collection is critical.

Incidence of methicillin-resistance and macrolide-lincosamide-streptogramin B resistance in a clinical sample of Staphylococcal isolates: a pharmacodynamic study

Incidence of methicillin-resistance and macrolide-lincosamide-streptogramin B resistance in a clinical sample of Staphylococcal isolates: a pharmacodynamic study

A Case of Perianal Abscess due to Panton-Valentine Leukocidin Positive Community-Associated Methicillin-Resistant Staphylococcus aureus : Report in Korea and Literature Review from the Far East

Submitted 9 December, 2007, accepted 15 February, 2008 This work was supported by the Korea Research Foundation Grant funded by the KoreanGovernment (MOEHRD) KRF-2005-003-E00119. Correspondence:Dong-GunLee, M.D. Department of Internal Medicine, St. Mary’ Hospital #62, Youido-dong, Youngdungpo-Gu, Seoul 150-713, Korea Tel:+82-2-590-2494, Fax:+82-2-535-2494 E-mail:symonlee@catholic.ac.kr (HA-MRSA). The incidence of methicillin resistance among nosocomial isolates of S. aureus is now higher than 60% in Korea (3). Moreover, recent reports have described an increasing incidence of community-associated MRSA (CA-MRSA) in patients who do not exhibit established risk factors for HA-MRSA and it has become a major concern worldwide (2, 4). Some epidemiological studies have suggested that most of CA-MRSA strains had association with lack of multi-drug resistance, predominance of staphylococcal cassette chromosome mec element (SCCmec) IV and high prevalence of Panton-Valentine leukocidin (PVL) 증 례

Is it possible to cure mediastinitis in patients with major postcardiac surgery complications?

Background. The prognosis for mediastinitis after cardiac operation has improved during the last two decades, but most series do not include patients who already have a major postoperative complication when the infection developed. Methods. Our 9-year prospective study of 371 consecutive patients with mediastinitis compared the characteristics of patients admitted to the intensive care unit primarily for mediastinitis with those who developed mediastinitis after intensive care unit admission for severe postoperative organ failure. Results. We identified 323 (87%) primary and 48 (13%) secondary mediastinitis patients. The incubation time for mediastinitis was longer for secondary mediastinitis patients, despite similar initial operations. Staphylococcus aureus was responsible for approximately 60% of the episodes in both groups; however, the incidence of methicillin resistance was 2.5 times higher in secondary mediastinitis patients ( p < 0.0001). The mediastinitis cure rate was similar for both groups. However, intensive care unit mortality (63% versus 21%), duration of mechanical ventilation (40 versus 9 days), and length of intensive care unit stay (53 versus 28 days) were significantly higher for secondary mediastinitis patients ( p < 0.0001). Conclusions. The presence of a prior major postoperative complication does not alter the cure rate of mediastinal infections, but does greatly reduce the survival rate.

Does Surgical Prophylaxis with Teicoplanin Constitute a Therapeutic Advance?

SummaryAntibiotic prophylaxis has become standard care not only in operations characterized by high infection rates but also in the vast majority of clean surgical procedures, including those that use foreign materials, grafts or prosthetic devices as well as non-implant surgery. While use of antibiotics in clean implant surgery is undisputed, it is still controversial in clean non-implant surgery. As antibiotic prophylaxis should be directed against expected pathogens, the glycopeptides are considered suitable alternative antibiotics to first and second generation cephalosporins in clean surgical procedures associated with a high risk of wound infections due to Gram-positive bacteria, including methicillin-resistant, and for patients allergic to beta-lactam antibiotics. In deciding whether to use a glycopeptide for prophylaxis, the current wound infection rates with methicillin-resistant Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis at single institutions need to be considered, to limit the use of glycopeptides to wards where the incidence of methicillin resistance is high. Of the two available glycopeptides, teicoplanin may be preferable to vancomycin for peri-operative prophylaxis because of its excellent tissue penetration, as indicated by the large volume of distribution, lower toxicity, and particularly long half-life, allowing single-dose administration in several surgical procedures. Clinical trials with teicoplanin prophylaxis in several types of clean surgical procedures including orthopedic, cardiac, vascular and dental operations, have shown it to be efficacious. This review focuses on results from clinical studies with this glycopeptide as prophylaxis in clean surgery.

Susceptibility of respiratory strains of Staphylococcus aureus to fifteen antibiotics: results of a collaborative surveillance study (1992-1993). The Alexander Project Collaborative Group.

As part of the Alexander Project during 1992 and 1993, 690 Staphylococcus aureus strains isolated from community-acquired lower respiratory tract infections by clinical microbiology centres located in Europe and the USA were analysed by a co-ordinating laboratory that determined minimal inhibitory concentrations of 15 antimicrobial agents using a standardised microdilution technique. The prevalence of penicillin-susceptible microorganisms in this collection of pathogens was significantly higher in Europe (21.2%) than it was in the USA (12.1%). Most isolates (72.5%), however, were strains that had acquired the ability to synthesise a beta-lactamase but which were sensitive to methicillin. The incidence of methicillin-resistance (9.1% overall) was highly variable depending on geographic location and year of isolation. Analysis of MIC50, MIC90, MIC range and modal MIC of the 15 antibiotics assayed disclosed no major differences between the data sets obtained during the 2-year survey. Except for methicillin-resistant S. aureus, the activity of all the beta-lactams tested, with the exclusion of penicillin, amoxycillin and cefixime (that were completely inactive), was satisfactory. The effect of beta-lactamase synthesis was inhibited by the combination of amoxycillin with clavulanate, and by cefuroxime and ceftriaxone. Cefaclor was slightly less effective. Erythromycin, clarithromycin and azithromycin showed identical cross-resistance rates (around 10%). Resistance to the macrolides was more frequent in the USA than in Europe and was the sole trait found to increase during the survey. Doxycycline, chloramphenicol, co-trimoxazole and the two fluoroquinolones tested (ofloxacin and ciprofloxacin) were remarkably effective (resistance lower than 1%). Only doxycycline and, to a lesser extent, co-trimoxazole were partially active against methicillin-resistant strains.

Trends in the epidemiology and antibiotic resistance of clinical Staphylococcus strains in Italy--a review

This review analyses the current Italian problem of clinical Staphylococcus isolates and trends in their antibiotic resistance. Most information has come from two recent nationwide collaborative studies. Some data have also been derived from particular experiences in individual laboratories. S. aureus was predominant among Staphylococcus isolates from most clinical sources. S. epidermidis predominated in strains isolated from artificial devices, blood, and cerebrospinal fluid. S. saprophyticus was isolated with greater frequency from outpatients than from inpatients, predominantly from urinary specimens. In spite of marked laboratory-to-laboratory and geographical variations, greater staphylococcal resistance to methicillin and most other antibiotics was noted. Overall, among clinical Staphylococcus strains isolated in Italy, more than a third of organisms from inpatients and more than a fifth of those from outpatients currently proved to be resistant to methicillin. The incidence of methicillin resistance was generally lower in Southern Italy than in the rest of the country, occurred at a twofold higher rate in isolates from inpatients than from outpatients, and was generally higher among isolates from intensive care units than from other hospital departments. There was increasing involvement of coagulase-negative staphylococci in human infections which made up about half of all clinical Staphylococcus isolates. Coagulase-negative staphylococci were more frequent than S. aureus in specimens from intensive care and surgical wards, and also were more resistant to many antibiotics including methicillin.

Epidemiologic study of Staphylococcus strains isolated from clinical material in 24 Italian Hospitals

A nationwide epidemiologic study of clinical Staphylococcus isolates was performed in Italy by 24 operative units distributed throughout the country. A total of 7,017 Staphylococcus strains were examined according to a standard protocol. Three species of acknowledged importance in human infections (namely S. aureus, S. epidermidis, and S. saprophyticus) were identified singly, whereas the other staphylococci were considered as a whole and designated Staphylococcus spp. S. aureus totalled 55% of total isolates and was reported by most operative units as the predominant species among isolates both from various inpatient departments and from outpatients. S. saprophyticus was twofold more frequent among isolates from out- than from inpatients. Susceptibility to methicillin varied considerably from hospital to hospital, but a general tendency toward an increasing spread of resistance was noted. The overall incidence of methicillin resistance (29%) resulted from a wide range of values generally higher in isolates from inpatients (35%) than from outpatients (21%). Particularly high percentages of resistance (45%) were recorded in isolates from intensive care departments. Susceptibility testing to four additional beta-lactams (cefoxitin, cefuroxime, cefotaxime, and piperacillin) and to four aminoglycosides (gentamicin, tobramycin, amikacin, and netilmicin) indicated that antibiotic resistance was widespread and in all species more frequent among methicillin-resistant than among methicillin-sensitive staphylococci. Netilmicin proved more active than the other antibiotics tested; its greater activity was most evident against methicillin-resistant strains. Coagulase-negative staphylococci were more resistant than S. aureus to methicillin and most of the other antibiotics, suggesting their increasing involvement in human infections.

Identification, clinical distribution, and susceptibility to methicillin and 18 additional antibiotics of clinical Staphylococcus isolates: nationwide investigation in Italy.

A multicentric study of clinical Staphylococcus isolates was performed by seven operative units working in different areas of Italy. Over a 6-month period, a total of 3,226 staphylococci, isolated from in- and outpatients, were identified and tested for antimicrobial susceptibility by a protocol agreed upon by all units. On the basis of their bacteriolytic-activity patterns and other conventional tests, the isolates were identified by lyogroups , which closely correlate with human Staphylococcus species. Lyogroup I (Staphylococcus aureus) and lyogroup III (Staphylococcus capitis) were the most and the least frequently isolated staphylococci, respectively. Significant differences depending on strain origin from in- or outpatients were only observed with lyogroup IV (i.e., novobiocin- resistant staphylococci), whose isolation from outpatients was three times greater than from inpatients. Lyogroup I was predominant among isolates from most clinical sources. Lyogroup IV predominated in strains isolated from the urinary tract; lyogroup V (Staphylococcus epidermidis) predominated in strains from blood, cerebrospinal fluid, and indwelling artificial devices; and lyogroup VI ( Staphylococcus hominis, Staphylococcus haemolyticus, and Staphylococcus warneri ) predominated in strains from bile and the male genital tract. The incidence of methicillin resistance within the different lyogroups varied from unit to unit, suggesting epidemiological differences among different hospitals and different geographical areas. On the whole, methicillin resistance was more frequent in coagulase-negative staphylococci than in S. aureus and ranged from 19% for lyogroups I and III to 30% for lyogroup II (Staphylococcus simulans). Laboratory testing with 18 additional antibiotics suggested the occurrence of some specific differences in susceptibility among the different lyogroups . The rate of organisms resistant to the various antibiotics was greater among methicillin-resistant than among methicillin -susceptible staphylococci; particularly marked differences occurred with cephalosporins, rifampin, gentamicin, and tobramycin. The results suggested an increasing spread in Italy, during the last few years, of staphylococcal resistance to methicillin and to many other antibiotics. Some questions about the actual reliability of laboratory tests for the determination of staphylococcal susceptibility to methicillin and other beta-lactam antibiotics were raised by parallel test performances in which both unsupplemented and 5% NaCl-supplemented Mueller-Hinton agars were used. The presence of NaCl heightened, on the whole, the number of resistant strains detected; however, a few isolates resistant in the unsupplemented medium and susceptible in the salt-supplemented medium were also encountered. This was true not only for methicillin but also for all other beta-lactam antibiotics tested except cefamandole. With cefamandole, the presence of 5% NaCl reduced the number of resistant strains detected.