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1.
Objective
Study of the clonality of methicillin-resistant Staphylococcus haemolyticus responsible of epidemic infections in a neonatal intensive care unit.Patients and methods
Methicillin-resistant Staphylococcus haemolyticus isolates were collected during the period from March 2004 to November 2006, from newborns, the clean hands of nurses and from disinfectant bottles used in the unit. Molecular typing by pulsed-field gel electrophoresis (PFGE) was achieved for all isolates.Results
Forty-six isolates of S. haemolyticus resistant to methicillin were collected from 42 newborns, the hand of two nurses and from two disinfectant bottles used in the unit. PFGE analysis revealed five types (A, B, C, D and E) among newborns isolates. Types A and B were predominant. Nurses’ isolates revealed PFGE types similar to types A and B. Disinfectant isolates were of type B. qacA/B PCR analysis revealed that the majority of type B isolates contain the disinfectant resistance gene qacA/B. No isolate of type A possessed this gene.Conclusion
These results suggest that MRSH neonatal infections are caused by a limited number of clones. Clone B was able to survive in disinfectant bottles and to conserve its ability to infect newborns. We therefore conclude that the disinfectant can serve as a reservoir for MRSH and point out the need to control all disinfectants used in a neonatal intensive care unit. 相似文献2.
O. Bouchami A. Ben Hassen H. de Lencastre M. Miragaia 《European journal of clinical microbiology & infectious diseases》2012,31(4):605-614
Staphylococcus haemolyticus is one of the most clinically relevant coagulase-negative staphylococci (CoNS), particularly in immunocompromised patients;
however, little is known regarding its molecular epidemiology. In this work, we characterized the genetic background and the
SCCmec region of 36 methicillin-resistant S. haemolyticus (MRSHae) and 10 methicillin-susceptible S. haemolyticus (MSSHae) collected from neutropenic patients in Tunisia between 2002 and 2004. The molecular characterization of MRSHae by
pulsed-field gel electrophoresis (PFGE) showed that the great majority of the isolates (77.8%) belonged to only four types.
SCCmec typing by polymerase chain reaction (PCR) and Southern hybridization showed that isolates belonging to each PFGE type could
carry either one or two SCCmec types. SCCmec V was the most common, but mec complex C was frequently associated to ccr allotypes other than ccrC. The mec complex class C was predominant in MRSHae (47%) and ccrC was predominant among both methicillin-resistant and -susceptible isolates (31 and 50%, respectively). Interestingly, one
half (50%) of the MRSHae isolates analyzed lacked the known ccr complexes (ccrAB and ccrC), although they carried the mecA. Conversely, all MSSHae carrying a ccrC complex were multidrug-resistant, although they lack the mecA. The results suggest that ccrC and mec complex C are frequent and may exist autonomously and independently of SCCmec type V in S. haemolyticus. Moreover, the data obtained suggest that small chromosomal rearrangements promoting the loss or structural variation of
mec and ccr complex appear to occur frequently, which probably provide S. haemolyticus with a specialized means for SCCmec trapping and/or diversification. 相似文献
3.
K.-H. Hung J.-J. Yan Y.-C. Lu H.-M. Chen J.-J. Wu 《European journal of clinical microbiology & infectious diseases》2011,30(10):1181-1184
The Clinical Laboratory Standards Institute recommends that if both cefoxitin and oxacillin are tested against Staphylococcus aureus and either result is measured as resistant, the organism should be reported as oxacillin resistant. This indicates that discrepancies
may be present between oxacillin and cefoxitin sensitivities in S. aureus. In this study, we aimed to investigate the discrepancy between oxacillin and cefoxitin susceptibility in S. aureus clinical isolates. Of 10,980 S. aureus isolates recovered from 2005 to 2010, 27 (0.3%) isolates with discordant results between oxacillin and cefoxitin were collected.
Fourteen (oxacillin diameters 10–12 mm) of the 27 strains were susceptible (MICs = 0.5–2 μg/ml) and 13 (6–13 mm) were resistant
(4–>256 μg/ml) to oxacillin. The cefoxitin MICs of 14 oxacillin-susceptible and 13 oxacillin-resistant strains ranged between
4 and 8 and 8 to 32 μg/ml, respectively. Discrepancies were present between oxacillin and cefoxitin in S. aureus, and these strains should be further tested for oxacillin MICs and for the mecA gene or β-lactamase activity. 相似文献
4.
J. Monterrubio-Villar C. González-Velasco S. Valdezate-Ramos A. Córdoba-López P. Villalón-Panzano J. A. Saéz-Nieto 《European journal of clinical microbiology & infectious diseases》2009,28(10):1281-1284
An outbreak of multidrug-resistant Acinetobacter baumannii (MRAB) occurred over the course of a 27-week period in our adult polyvalent intensive care unit (ICU). Twenty-one patients
were affected, and 72 strains were identified from different clinical samples. The strains were resistant to all antibiotics
except for colistin and ampicillin/sulbactam. Forty-nine MRAB strains collected from 18 patients were analysed by pulsed-field
gel electrophoresis (PFGE). This analysis revealed four highly-related PFGE types (genetic similarity index >90%) termed 1,
2, 3 and 4, that were isolated in 13, seven, one, and three patients, respectively. A single PFGE type was identified from
five of ten patients with successive isolation of MRAB; in the other five patients, two or three PFGE types were detected.
This suggested phased evolution of PFGE types 2, 3 and 4 from PFGE type 1. Global mortality was high (13 patients; 62%). Non-survivors
had higher APACHE II scores than survivors on the date that MRAB was isolated (OR = 1.57; 95% CI [1.02, 2.44]). The outbreak
was controlled after implementation of an extensive infection control program. 相似文献
5.
B. Krucsó M. Gacs B. Libisch Zs. Vargáné Hunyadi K. Molnár M. Füzi J. Pászti 《European journal of clinical microbiology & infectious diseases》2007,26(11):807-811
Our aim was to characterise by molecular techniques group A streptococci isolated from invasive infections in Hungary in 2004–2005.
Twenty-six nonduplicate invasive GAS isolates were selected and examined. The mortality rate proved high (52.3%) for those
cases (n = 21) where data were available. Predominant emm types were emm1 (n = 13, 50%) and emm80 (n = 5, 19.2%), but other M types (emm4, emm28, emm66, emm81.1, emm82, emm84) were also identified. Eight different PFGE types were distinguished, and each emm type showed an individual PFGE pattern. Our results show that—similarly to results obtained in several other countries—emm type 1 strains predominate among invasive GAS isolates, and that emm 1 type strains recovered from severe streptococcal infections were associated with the presence of the speA gene. The rate for macrolide resistance proved low: only two isolates showed elevated MICs for erythromycin. 相似文献
6.
K. Kristóf E. Kocsis D. Szabó S. Kardos V. Cser K. Nagy P. Hermann F. Rozgonyi 《European journal of clinical microbiology & infectious diseases》2011,30(5):691-699
The purpose of this study was to quantify the impact of Staphylococcus haemolyticus in the epidemiology of the blood stream infection (BSI) and to characterize the rates and quantitative levels of resistance
to antistaphylococcal drugs. During an eight-year period, 2967 BSIs of the patients hospitalized in different clinical departments
of the Semmelweis University, Budapest, Hungary were analyzed. One hundred eighty-four were caused by S. haemolyticus, amounting to 6% of all infections. The antibacterial resistance of S. haemolyticus isolates was investigated by the broth microdilution method, vancomycin agar screen, population analysis profile and PCR
for mecA, vanA and vanB genes detection. Epidemiological investigation was processed by determining phenotypic antibiotic resistance patterns and
PFGE profiles. Extremely high MIC levels of resistance were obtained to oxacillin, erythromycin, clindamycin, gentamicin and
ciprofloxacin. The incidence of teicoplanin reduced susceptibility revealed 32% without possessing either the vanA or vanB gene by the strains. PFGE revealed 56 well-defined genotypes indicating no clonal relationship of the strains. The propensity
of S. haemolyticus to acquire resistance and its pathogenic potential in immunocompromised patients, especially among preterm neonates, emphasise
the importance of species level identification of coagulase-negative staphylococci and routinely determine the MIC of proper
antibacterial agents for these isolates. 相似文献
7.
S. Gröbner V. A. J. Kempf 《European journal of clinical microbiology & infectious diseases》2007,26(10):751-754
For the rapid detection of methicillin-resistant staphylococci directly from blood cultures containing gram-positive cocci
in clusters, we implemented a real-time (LightCycler) polymerase chain reaction (PCR) specific for the Staphylococcus aureus nuc gene encoding nuclease and the mecA gene encoding methicillin resistance. For the 475 positive blood cultures tested, the assay turned out to have 100% sensitivity
and 100% specificity for the identification of methicillin-susceptible (n = 108) and methicillin-resistant (n = 34) S. aureus. When coagulase-negative staphylococci (CoNS) were included, the overall sensitivity for the detection of methicillin resistance
was 93% and the specificity was 99%. Real-time PCR for nuc and mecA from blood culture bottles with staphylococci yields therefore a rapid (2–3 h) identification of S. aureus and CoNS including methicillin resistance. 相似文献
8.
K.-H. Hung J.-J. Yan Y.-C. Lu H.-M. Chen J.-J. Wu 《European journal of clinical microbiology & infectious diseases》2011,30(6):785-788
The Clinical and Laboratory Standards Institute (CLSI) recommends testing coagulase-negative staphylococci (CoNS) strains
to determine resistance against oxacillin by testing for mecA, PBP2a, or with cefoxitin disk. However, discrepant results of resistance to oxacillin and susceptibility to cefoxitin were
found. In this study, we aimed to investigate the oxacillin resistance and cefoxitin susceptibility of CoNS in Taiwan. Of
9,017 strains collected from 2005 to 2010, 131 (1.5%) of the isolates were oxacillin-resistant and cefoxitin-susceptible.
Species identification was carried out using the Vitek 2 system or 16S ribosomal RNA sequencing. Oxacillin minimum inhibitory
concentrations (MICs) were examined by the agar dilution method. The presence of mecA and the activity of β-lactamase were performed by polymerase chain reaction (PCR) and Cefinase disks, respectively. Overall,
33% (43/129) of the strains carried mecA and 43% (37/86) of mecA-negative isolates tested positive for β-lactamase. The remaining 49 isolates were negative for both mecA and β-lactamase, and were mainly Staphylococcus cohnii ssp. urealyticus and S. saprophyticus (oxacillin MICs 0.5–2 μg/ml) obtained from bloodstream and urinary tract infections. Our study suggests that incorrect reporting
can be found in CoNS using cefoxitin disk alone to determine the susceptibility to oxacillin, and the strains should be further
tested for oxacillin MICs and detection of the mecA gene or β-lactamase activity. 相似文献
9.
Conceição T. Aires-de-Sousa M. Pona N. Brito M. J. Barradas C. Coelho R. Sardinha T. Sancho L. de Sousa G. do Céu Machado M. de Lencastre H. 《European journal of clinical microbiology & infectious diseases》2011,30(2):293-297
In order to evaluate the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Portugal, we analyzed a collection of 38 S. aureus isolates recovered from 30 children attending the pediatric emergency department of a central hospital in Lisbon due to skin
and soft tissue infections. Molecular characterization identified seven clonal lineages among the 35 methicillin-susceptible
S. aureus (MSSA) isolates, of which the major lineage PFGE A/t159/ST121 included 63% of the isolates. The three MRSA isolates belonged
to the Pediatric clone PFGE D/t535/ST5-IV (n = 2) and to the European CA-MRSA clone PFGE G/t044/ST80-IVc (n = 1). All isolates harbored several virulence factors, namely, leukocidins. Panton–Valentine leukocidin (PVL) was produced
by isolates from five MSSA lineages and by the ST80 MRSA. Of interest, this is the first reported isolation of CA-MRSA ST80
in Portugal. 相似文献
10.
K. Ben Slama H. Gharsa N. Klibi A. Jouini C. Lozano E. Gómez-Sanz M. Zarazaga A. Boudabous C. Torres 《European journal of clinical microbiology & infectious diseases》2011,30(4):499-508
Nasal swabs of 423 healthy humans who showed different levels of contact with animals (frequent, 168; sporadic, 94; no contact,
161) were obtained in Tunisia (2008–2009), and 99 of them presented other associated risk factors. Methicillin-resistant Staphylococcus aureus (MRSA) was detected in one of these 423 samples (0.24%), retrieved from a veterinarian. The MRSA isolate was mecA-positive, typed as ST80-t203-SCCmecIVc-agrIII, and contained tet(K), ant(6)-Ia, and aph(3′)-IIIa genes encoding tetracycline, streptomycin, and kanamycin resistance, respectively. This MRSA isolate also contained the lukF/lukS virulence gene encoding Panton–Valentine leukocidin. Fifty-four (12.8%) additional nasal samples contained methicillin-susceptible
S. aureus (MSSA) and one isolate/sample was characterized. A high diversity of spa types (n = 43; 4 new) and pulsed-field gel electrophoresis (PFGE) types (n = 37) was detected among the 55 recovered S. aureus strains. The percentages of antimicrobial resistance/detected resistance genes were as follows: tetracycline [22%/tet(K)-tet(L)-tet(M)], erythromycin [5%/msrA], ciprofloxacin [14.5%], trimethoprim–sulfamethoxazole [2%/dfrA], streptomycin [11%/ant(6)-Ia], kanamycin [7%/aph(3′)-IIIa], amikacin [5%], and chloramphenicol [2%]. Four and two isolates carried the lukF/lukS and eta and/or etb genes, respectively, and always in individuals with contact with animals. Eleven isolates carried the tst gene and were recovered from individuals with different levels of contact with animals. 相似文献
11.
L. Fenner R. Frei M. Gregory M. Dangel A. Stranden A. F. Widmer 《European journal of clinical microbiology & infectious diseases》2008,27(12):1201-1207
A prospective study was conducted during a one-year period between 2006 and 2007 to describe the epidemiology of Clostridium difficile-associated disease (CDAD) at University Hospital Basel, Switzerland (UHBS) and to determine phenotypic and genotypic features
of C. difficile strains isolated at the Microbiology Laboratory UHBS including strains from regional non-university hospitals. We prospectively
identified 78 CDAD cases at UHBS with an incidence of 2.65/1,000 hospitalised patients or 2.3/10,000 patient-days. Sixteen
patients (20.5%) were infected with clindamycin-resistant strains of PCR-ribotype 027 during an outbreak at the geriatric
hospital. Among 124 single-patient isolates, 28 (22.6%) were resistant to moxifloxacin and 34 (27.4%) were resistant to clindamycin,
but all remained susceptible to metronidazole and vancomycin. Of 102 toxigenic isolates, 19 (18.7%) had an 18-bp deletion
in the tcdC gene, eight (7.8%) a 39-bp deletion, and one (1.0%) a 54-bp deletion. Genes for binary toxin were present in 27 (21.8%).
PCR-ribotype 027 was associated with older age (median age 83.5 vs. 65.5 years, p < 0.0001) and longer duration of hospitalisation before onset of disease (median 15.5 vs. 9 days, p = 0.014) with a trend towards higher crude mortality, more severe disease, and previous use of macrolides compared to ribotype
non-027. Overall, severe disease correlated with use of a nasogastric tube and surprisingly shorter duration of hospitalisation
before onset of disease. Today, laboratory-based and epidemiological surveillance systems are required to monitor CDAD cases
and emergence of new epidemic strains. 相似文献
12.
M. Kardén-Lilja S. Ibrahem J. Vuopio-Varkila S. Salmenlinna O. Lyytikäinen L. Siira A. Virolainen 《European journal of clinical microbiology & infectious diseases》2007,26(10):729-733
Methicillin-resistant Staphylococcus aureus (MRSA) strains from Finland covering years 1997–1999 were studied for the presence of Panton-Valentine leukocidin (PVL) gene
loci, and the clinically well-defined community-acquired MRSA (CA-MRSA) strains (n = 108) also for staphylococcal chromosomal cassette mec (SCCmec) and multilocus sequence types (MLST). Only a minority (12%) of the CA-MRSA strains contained the PVL gene loci and possessed
genotypes formerly described as typical to CA-MRSA strains. The majority of these strains were heterogenous by MLST and pulsed-field
gel electrophoresis (PFGE) analysis but, however, harboured the SCCmec cassette type IV. In conclusion, it seems doubtful to consider only molecular characteristics such as the presence of PVL
genes as definite markers for CA-MRSA strains.
This data was partly presented at the 14th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID), May
1–4, 2004, Prague, Czech Republic, Poster no. P1014. 相似文献
13.
E. Ahlstrand K. Svensson L. Persson U. Tidefelt B. Söderquist 《European journal of clinical microbiology & infectious diseases》2011,30(11):1349-1354
The aim of this study was to determine if there was a long-term increase in glycopeptide minimum inhibitory concentration
(MIC) values, MIC creep, among bloodstream isolates of Staphylococcus epidermidis and S. haemolyticus isolated from patients with hematological malignancies. We conducted a retrospective single-center study where all positive
blood cultures of S. epidermidis (n = 387) and S. haemolyticus (n = 19) isolated from patients with hematological malignancies during three decades, 1980 to 2009, were re-evaluated for the
presence of reduced susceptibility to vancomycin and teicoplanin. Three different methods for the detection of reduced susceptibility
to glycopeptides were used; standard Etest, macromethod Etest, and glycopeptide resistance detection (GRD) Etest. The median
MIC value for vancomycin was 2 mg/L. MIC values for vancomycin and teicoplanin did not show any statistically significant
increase during the study period. The presence of heterogeneously glycopeptide-intermediate staphylococci (hGIS) was analyzed
among 405 coagulase-negative staphylococci (CoNS) isolates. hGIS were found in 31–45% of the CoNS isolates by the macromethod
Etest and in 53–67% by the GRD Etest during the three decades. In conclusion, we did not observe any long-term glycopeptide
MIC creep determined by the standard Etest, although a high and increasing proportion of heterogeneous vancomycin resistance
was observed. 相似文献
14.
G. A. Syrogiannopoulos I. N. Grivea G. D. Katopodis P. Geslin M. R. Jacobs N. G. Beratis 《European journal of clinical microbiology & infectious diseases》2000,19(4):288-293
The prevalence, resistance patterns and serotypes of antibiotic-resistant Streptococcus pneumoniae strains recovered from Greek carriers under 24 months of age were studied. From February 1997 to April 1998, nasopharyngeal
cultures were performed in 1269 children (ages 2–23 months, median 11 months) living in various areas of central and southern
Greece. Resistance (including both intermediate and resistant isolates) to one or more antimicrobial agents was found in 132
of the 421 (31%) Streptococcus pneumoniae isolates, as follows: penicillin, 9% intermediate, 7.6% resistant; cefotaxime, 5.2% intermediate, 0.5% resistant; erythromycin,
0.7% intermediate, 18.1% resistant; clindamycin, 0.2% intermediate, 12.4% resistant; tetracycline, 0.7% intermediate, 16.4%
resistant; chloramphenicol, 12.4% resistant; and trimethoprim-sulfamethoxazole, 3.8% intermediate, 14.3% resistant. The MICs
of penicillin for 66% of the penicillin-nonsusceptible pneumococci were 1–4 μg/ml. Multidrug resistance was found in 64% of
penicillin-nonsusceptible and 37% of penicillin-susceptible strains. Sixty-two percent of the penicillin-susceptible, multidrug-resistant
strains belonged to serotype 6B and were resistant to all five non-β-lactam agents tested. This notable serotype 6B resistance
pattern was described for the first time in a previous study performed from December 1995 to February 1996 in the city of
Patras, southwestern Greece. Seventy-two percent of antibiotic-resistant isolates belonged to serotypes 6B, 9V, 14, 18C, 19F
and 23F. These results document the spread of resistant pneumococcal strains in central and southern Greece, many of which
are multidrug resistant. 相似文献
15.
Biochemical mechanisms of insecticide resistance of thermal exposed and unexposed Culex quinquefasciatus strains are evaluated, which were not studied earlier. The activity of α- and β-carboxylesterases and acetylcholinesterase
of malathion susceptible and resistant strains were compared after thermal treatment. Three-day-old adult females were used
for the malathion susceptibility test and biochemical assays, and males were used only for the susceptibility test. Thermal
exposure brought about increase in resistance levels from 85% to 90% in males and 91% to 96.6% in females of resistant strain.
The resistance status of the susceptibility strain was unchanged after thermal exposure. The activities of α- and β-carboxylesterase
of susceptible mosquitoes were within 800 and 700 U/mg protein, respectively. The α-carboxylesterase activity of the thermal
exposed malathion-resistant population was significantly (t test, P < 0.05) higher than the unexposed resistant population, and the reverse was recorded in β-carboxylesterase. The α-carboxylesterase
activity of susceptible population was lower than the resistant population. The activity of α-carboxylesterase was higher
than the β-carboxylesterase in both the strains. Among the malathion resistant C. quinquefasciatus population, 2.3% population exhibited 30–40% inhibition which increased to 5.8% after the thermal exposure. Thermal exposure
of mosquitoes increased the activity of both α-carboxylesterases and acetylcholinesterase but decreased the activity of β-carboxylesterase. 相似文献
16.
A.-C. Uhlemann C. Dumortier C. Hafer B. S. Taylor J. Sánchez E. C. Rodriguez-Taveras P. Leon R. Rojas C. Olive F. D. Lowy 《European journal of clinical microbiology & infectious diseases》2012,31(4):505-511
Staphylococcus aureus infections continue to pose a global public health problem. Frequently, this epidemic is driven by the successful spread
of single S. aureus clones within a geographic region, but international travel has been recognized as a potential risk factor for S. aureus infections. To study the molecular epidemiology of S. aureus infections in the Caribbean, a major international tourist destination, we collected methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) isolates from community-onset infections in the Dominican Republic (n = 112) and Martinique (n = 143). Isolates were characterized by a combination of pulsed-field gel electrophoresis (PFGE), spa typing, and multilocus sequence typing (MLST) typing. In Martinique, MRSA infections (n = 56) were mainly caused by t304-ST8 strains (n = 44), whereas MSSA isolates were derived from genetically diverse backgrounds. Among MRSA strains (n = 22) from the Dominican Republic, ST5, ST30, and ST72 predominated, while ST30 t665-PVL+ (30/90) accounted for a substantial
number of MSSA infections. Despite epidemiological differences in sample collections from both countries, a considerable number
of MSSA infections (~10%) were caused by ST5 and ST398 isolates at each site. Further phylogenetic analysis suggests the presence
of lineages shared by the two countries, followed by recent genetic diversification unique to each site. Our findings also
imply the frequent import and exchange of international S. aureus strains in the Caribbean. 相似文献
17.
TANJA PASANEN MAIJA KORKEILA SOINTU MERO EVELIINA TARKKA HELI PIIPARINEN JAANA VUOPIO‐VARKILA MARTTI VAARA PÄIVI TISSARI 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2010,118(1):74-80
Pasanen T, Korkeila M, Mero S, Tarkka E, Piiparinen H, Vuopio‐Varkila J, Vaara M, Tissari P. A selective broth enrichment combined with real‐time nuc‐mecA‐PCR in the exclusion of MRSA. APMIS 2010; 118: 74–80. We analyzed the performance of a selective enrichment broth combined with Taqman‐based real‐time duplex nuc‐mecA‐PCR to expedite the screening of methicillin‐resistant Staphylococcus aureus (MRSA). We found the broth to be able to select MRSA strains (oxacillin MIC range 4–256 μg/ml) from MSSA strains. A total of 31 MRSA strains were found from 1250 clinical samples screened. The nuc‐mecA‐PCR was positive from all enrichment broths containing MRSA. From the remaining 1219 samples negative for MRSA on culture/subculture, 138 samples were nuc+/mecA+ in PCR. The sensitivity of the test was 93.5%, specificity 88.6%, positive predictive value 17.3%, and negative predictive value 99.8% as compared to culture. Thus, with this method, the negative MRSA results can be reliably reported within 24–48 h from sampling. The method is a practical additional alternative to those already described for the same purpose. 相似文献
18.
E. Chatzakis E. Scoulica N. Papageorgiou S. Maraki G. Samonis E. Galanakis 《European journal of clinical microbiology & infectious diseases》2011,30(9):1111-1117
Infant colonization by Staphylococcus aureus has not been adequately investigated. In this study, we aimed to define determinants associated with the carriage of S. aureus in early infancy. Serial nasal swabs were collected from 128 infants and their mothers at months 0, 6, and 12 postpartum.
S. aureus isolates were characterized by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing, and the presence of chromosomal mecA and of Panton–Valentine leukocidin (PVL) genes. S. aureus was isolated in 17.7% and 15.7% of swabs from infants and mothers, respectively. Carriage rates were higher in infants with
carrier mothers, non-smoking mothers, and many siblings. Persistent carriage rates were higher in infants with carrier or
non-smoking mothers. S. aureus typing revealed identical strains in 10/15 investigated infant–mother pairs. Among 19 investigated S. aureus isolates from infants, ten harbored mecA and two harbored PVL genes, and these determinants were concomitantly present in isolates from mothers. Resistance to methicillin was 43.6% among
all isolates from infants. In conclusion, isolates from infants were commonly identical to isolates from their mothers, pointing
to a principal role of maternal carriage in S. aureus colonization in infants. 相似文献
19.
R. M. Anthony A. M. Connor E. G. M. Power G. L. French 《European journal of clinical microbiology & infectious diseases》1999,18(1):30-34
The minimum inhibitory concentrations (MICs) of mupirocin were determined by the E test (AB Biodisk, Sweden) and the agar
dilution method for 107 staphylococci. The organisms consisted of 34 coagulase-negative staphylococci and 73 methicillin-resistant
Staphylococcus aureus. Polymerase chain reaction (PCR) primers designed to amplify a 456 bp region of the plasmid-borne isoleucyl tRNA synthetase
gene (ileS–2), responsible for high-level mupirocin resistance in staphylococci, were used on DNA preparations from these isolates.
Isolates with high-level mupirocin resistance due to the ileS–2 gene should be PCR positive. There was close correlation between the E test and agar dilution MIC values, with only two
strains differing by more than two serial dilutions. Most (51 of 54 strains) of the high-level resistant strains (MIC>256 μg/ml)
were resistant to the highest concentration of mupirocin tested (1024 μg/ml). PCR correctly classified all but four (96%)
of the isolates in accordance with the results of agar dilution. All four isolates that gave discrepant results were methicillin-resistant
Staphylococcus aureus. Two of these were PCR positive, yet the MIC of mupirocin for these strains was <0.06 μg/ml; on prolonged incubation they
produced halos within the inhibition zone on agar diffusion testing, suggesting that the phenotypic results may have been
erroneous. One of 54 isolates for which the MIC exceeded 256 μg/ml was PCR negative when tested by the original methodology,
but a 456 bp product was produced when retested using a lowered annealing temperature. One isolate for which the MIC of mupirocin
was 16 μg/ml by agar dilution and 8 μg/ml by the E test was positive by PCR. PCR of the ileS–2 gene is a useful, rapid method for detecting high-level mupirocin resistance in staphylococci. 相似文献
20.
E. J. M. Verkade C. J. M. M. Verhulst X. W. Huijsdens J. A. J. W. Kluytmans 《European journal of clinical microbiology & infectious diseases》2010,29(5):503-507
The in vitro activity of tigecycline was determined using a well-defined collection of methicillin-resistant Staphylococcus aureus (MRSA) isolates (n = 202), including 33 livestock-associated strains. Susceptibility testing was performed using the Etest system. Among the
202 MRSA strains, three (1.5%) had a minimum inhibitory concentration (MIC) value for tigecycline greater than 0.5 mg/l, which
are considered to be resistant. When these strains were tested using Iso-Sensitest medium, the MICs were substantially lower
and no resistance was found. This discrepancy warrants further investigations into the preferred test conditions for tigecycline.
In conclusion, tigecycline showed good activity against MRSA strains in vitro. 相似文献