Diagnostic Microbiology & Infectious Disease

Direct testing of bronchoalveolar lavages from ventilator-associated pneumonia patients

2012-04-09

Abstract: In line with a rapid de-escalation of empirical antimicrobial therapy, this study assessed the validity of an E-test–based direct specimen testing method on bronchoalveolar lavage (BAL) samples from ventilator-associated pneumonia (VAP) patients. E-test strips were directly applied onto Mueller-Hinton agar plates seeded with BAL samples and read after 24 h of incubation. In parallel, the BAL samples were analyzed by the routine diagnostic laboratory. The microbroth dilution approach was used as a control method. In a cohort of 20 patients, 135 microorganism–antibiotic combinations were studied. Total agreement between the 2 methods was achieved for 88.9% combinations, with 1.5% very major errors (isolates susceptible by E-test and reported resistant by the diagnostic laboratory) and 9.6% major errors (isolates resistant by E-test and reported susceptible by the diagnostic laboratory). These results indicate that applying E-test directly on BAL samples is a promising method for obtaining susceptibility data after 24 h in critical patients with VAP.

Identification and molecular discrimination of toxigenic and nontoxigenic diphtheria Corynebacterium strains by combined real-time polymerase chain reaction assays

2012-04-11

Abstract: With the recognition of several diphtheria outbreaks and the emergence of nontoxigenic corynebacteria strains, there has been renewed interest in the development of laboratory diagnostic methods. Previously reported polymerase chain reaction (PCR) assays can have low diagnostic sensitivity or give species misidentifications among clinical isolates. The aim of the present study was the development of combined real-time PCR assays, based on the tox and rpoB genes, for the detection and differentiation of toxigenic and nontoxigenic corynebacteria. By the PCR tox assay, it was possible to perform the direct identification of DT tox gene of Corynebacterium diphtheriae and Corynebacterium ulcerans, while the PCR rpoB assay differentiated C. diphtheriae from C. ulcerans, irrespective of their toxigenic status. In addition, we detected the DT toxin of Corynebacterium pseudotuberculosis for the first time. These assays revealed high sensitivity, specificity, and reproducibility, and the availability of plasmid controls will facilitate further research into the diagnostics of diphtheria corynebacteria.

Development of a multiplex polymerase chain reaction assay for diarrheagenic Escherichia coli and Shigella spp. and its evaluation on colonies, culture broths, and stool

2012-04-27

Abstract: Detection of diarrheagenic Escherichia coli (DEC) typically depends on identification of virulence genes from stool cultures, not on stool itself. We developed a multiplex polymerase chain reaction (PCR) assay that detects key DEC virulence genes (stx1, stx2, eae, bfpA, ipaH, LT, STh, aaiC, aatA). The assay involved a multiplex PCR reaction followed by detection of amplicon(s) using Luminex beads. The assay was evaluated on over 100 colony and broth specimens. We then evaluated the assay using DNA extracted from stool, colony pools, and Gram-negative broths, using stool spiked with known quantities of DEC. Performance of the assay on stool DNA was most quantitative, while stool broth DNA offered the lowest limit of detection. The assay was prospectively evaluated on clinical specimens in Tanzania. Stool DNA yielded higher sensitivity than colony pools compared with broth DNA as the standard. We propose using this assay to screen for DEC directly in stool or stool broths.

Direct inoculation method using BacT/ALERT 3D and BD Phoenix System allows rapid and accurate identification and susceptibility testing for both Gram-positive cocci and Gram-negative rods in aerobic blood cultures

2012-04-11

Abstract: This study describes a direct inoculation method using the automated BacT/ALERT 3D and the BD Phoenix System in combination for identification and susceptibility testing of isolates from positive blood cultures. Organism identification and susceptibility results were compared with the conventional method for 211 positive aerobic blood cultures. Of 110 Gram-positive cocci (GPCs), 98 (89.1%) isolates were correctly identified to the species level. Of 101 Gram-negative rods (GNRs), 98 (97.0%) isolates were correctly identified to the species level. The overall categorical agreement in antimicrobial susceptibility testing among the 110 GPCs was 92.7%, with 0.04% very major and 0.7% major error rates. The overall categorical agreement among 78 isolates of enterobacteria and 23 isolates of nonfermenters in GNRs was 99.5% and 91.1%, respectively, with no major errors identified. We conclude that, compared with previously reported direct inoculation methods, our method is superior in identification and susceptibility testing of GPCs.

In vitro efficacy of the combination of voriconazole and anidulafungin against voriconazole-resistant cyp51A mutants of Aspergillus fumigatus

Suganthini Krishnan-Natesan, Wenjuan Wu, Pranatharthi H. Chandrasekar — 2012-06-01

Abstract: We selected voriconazole-resistant (VCZ-R) Aspergillus fumigatus in the laboratory, characterized the cyp51A gene for possible mutations and evaluated the in vitro activities of voriconazole and anidulafungin alone and in combination against VCZ-R isolates of A. fumigatus using a fractional inhibitory concentration index (FICI) methodology. Voriconazole-resistant isolates were selected from wild-type A. fumigatus isolates in the laboratory by a 2-step selection process (plus 1 clinical isolate). The MICs of azoles (VCZ, posaconazole, itraconazole) and echinocandins (anidulafungin, micafungin, and caspofungin) for all A. fumigatus isolates were then determined in RPMI1640 using the broth microdilution technique recommended by the Clinical Laboratory and Standards Institute M38-A2 methodology and the FICI calculated. The combination of VCZ and anidulafungin was synergistic (FICI <0.5) not only against VCZ-susceptible isolates, but also against 8 of 10 VCZ-R, G448S mutants of A. fumigatus. The combination demonstrated synergy against the VCZ-R clinical isolate as well.

Performance of 2 commercial real-time polymerase chain reaction assays for the detection of Aspergillus and Pneumocystis DNA in bronchoalveolar lavage fluid samples from critical care patients

2012-04-16

Abstract: This article investigates the performance of 2 commercial real-time polymerase chain reaction (PCR) assays, MycAssay™ Aspergillus (MycAspAssay) and MycAssay™ Pneumocystis (MycPCPAssay), on the ABI 7300 platform for the detection of Aspergillus (Asp) or Pneumocystis jirovecii (Pj) DNA in bronchoalveolar lavage (BAL) samples from 20 patients. Operationally, patients enrolled were clustered into 3 groups: invasive aspergillosis group (IA, 7 patients), Pj pneumonia group (PCP, 8 patients), and negative control group (5 patients). All the IA patients were MycAspAssay positive, whereas 12 non-IA patients returned negative PCR results. Furthermore, 7 of 8 PCP patients were MycPCPAssay positive, while 9 non-PCP patients were PCR negative. In conclusion, these data provide an early indication of the effectiveness of both the MycAspAssay and MycPCPAssay on the ABI 7300 platform for the detection of either Asp or Pj DNA in BAL from patients with deep fungal infections.

Epidemiologic cutoff values for triazole drugs in Cryptococcus gattii: correlation of molecular type and in vitro susceptibility

2012-04-11

Abstract: Cryptococcus gattii causes infection in tropical and subtropical regions worldwide but has garnered increased attention since its 1999 emergence in North America. C. gattii can be divided into 4 molecular types that may represent cryptic species. Recent evidence has shown that azole antifungal MIC values differ among these molecular types. We tested a large collection of C. gattii isolates for susceptibility to 4 azole drugs. We found that isolates of molecular type VGII have the highest geometric mean (GM) fluconazole MIC values (8.6 μg/mL), while isolates of molecular type VGI have the lowest (1.7 μg/mL). For fluconazole, itraconazole, and voriconazole GM MIC values, VGI < VGIII < VGIV < VGII. The GM MIC values for posaconazole were similarly represented across molecular types, with the exception that VGII < VGIII and VGIV. We used the MIC values to establish preliminary epidemiologic cutoff values for each azole and molecular type of C. gattii.

Clinical characteristics and risk factors of ocular candidiasis

2012-04-16

Abstract: Ocular candidiasis is a major complication of Candida bloodstream infection (BSI). This study was performed to reveal the clinical characteristics of ocular candidiasis. Of the 220 patients with Candida BSI, 204 cases received ophthalmology consultations between January 2005 and December 2011 at 2 teaching hospitals. Fifty-four (26.5%) cases had findings consistent with the diagnosis of ocular candidiasis. Of these 54 cases, 43 (79.6%) were diagnosed within 7 days after a positive blood culture. Among ocular candidiasis cases, more cases were due to Candida albicans (P =0.034 odds ratio [OR]; 3.68 95% confidence interval [CI] 1.11–12.2) and had higher β-d-glucan values (P = 0.001 OR; 9.99 95% CI 2.60–21.3). We need to consider fundoscopic examination to be performed within the first 7 days of therapy, especially for those patients who have C. albicans BSIs and higher β-d-glucan values. Additionally, follow-up fundoscopic examination should be considered before stopping therapy for high-risk patients.

Clinical comparison of the Bactec Mycosis IC/F, BacT/Alert FA, and BacT/Alert FN blood culture vials for the detection of candidemia

Eva-Lena Ericson, Lena Klingspor, Måns Ullberg, Volkan Özenci — 2012-04-11

Abstract: The present study analyzed the performance of Bactec Mycosis IC/F, BacT/Alert FA, and BacT/Alert FN vials in detection and time to detection (TTD) of Candida spp. in 179 simultaneous blood cultures. The Mycosis IC/F, BacT/Alert FA, and BacT/Alert FN vials could detect Candida spp. in 144 (80.45%) of 179, 149 (83.24%) of 179, and 8 (4.47%) of 179 samples, respectively. With the presence of antifungal therapy, the numbers of positive vials were higher in BacT/Alert FA compared to Mycosis IC/F, 87/99 versus 73/99, respectively (P < 0.05). TTD (SD) for C. albicans was shorter in Mycosis IC/F than in BacT/Alert FA vials without antifungal therapy, 20.89 (9.33) versus 28.26 (9.77), respectively (P < 0.01). The detection of Candida spp., with concomitant bacteremia, was higher in Mycosis IC/F than in BacT/Alert FA vials, 28/30 and 19/30, respectively (P = 0.01). The present data show that the use of Bactec Mycosis IC/F together with BacT/Alert FA vials might improve the detection of Candida spp.

Clinical significance of Candida colonization of intravascular catheters in the absence of documented candidemia

2012-04-09

Abstract: In order to assess the significance of Candida colonization of intravascular catheters (IVC) in patients without documented candidemia, we retrospectively reviewed all Candida-positive IVC tip cultures over a 4-year period. Cases were defined as those with a culture yielding ≥15 colony-forming units of Candida spp. that either did not have blood cultures (BC) taken or had concomitant BC negative for Candida. Patients were followed up until death or 8 months after discharge. Risk factors for poor outcome following IVC removal (death, candidemia, or Candida-related complication) were analyzed. We analyzed a total of 40 patients. Overall mortality was 40.0%, with no death directly attributed to Candida infection. Twenty-two patients received antifungal therapy at the time of IVC removal. Only 1 patient developed a metastatic complication (chorioretinitis) attributable to transient candidemia (2.5% of the global cohort and 3.7% among those with concomitant BC). There were no cases of subsequent candidemia. In the multivariate analysis, the use of antifungal therapy did not show any impact on the risk of poor outcome. The risk of invasive disease in patients with isolated IVC colonization by Candida seems to be low. Nevertheless, the initiation of systemic antifungal therapy should be carefully considered in such context.

Human rhinovirus and human respiratory enterovirus (EV68 and EV104) infections in hospitalized patients in Italy, 2008–2009

2012-04-12

Abstract: The epidemiology of picornavirus infections along with associated risk factors for lower respiratory tract infections (LRTI) and duration of virus shedding were investigated in 985 hospitalized patients in the period October 2008–September 2009. One-third of patients were human rhinovirus (HRV)–positive. Of 336 HRV-associated episodes, 153 (45.5%) were sustained by HRV-A, 31 (9.2%) by HRV-B, and 93 (27.7%) by HRV-C, while 7 episodes showed multiple HRV types and 52 were sustained by undefined HRV species. Independent risk factors for LRTI included high viral load and age less than 5 years. Twenty (2.1%) patients were enterovirus (EV)-positive (12 had EV-68, 7 EV-104, and 1 E-13 infection). Half of the EV-positive patients had a LRTI and were younger with respect to patients with upper RTI (median 18 months versus 37 years; P < 0.001). HRVs are often the cause of LRTI in children less than 5 years, frequently in association with a high viral load.

Prediction of community-onset bacteremia among febrile adults visiting an emergency department: rigor matters

2012-03-30

Abstract: Objectives: Bacteremia is a severe bacterial infection with significant mortality and morbidity. Clinical parameters that reliably predict the presence of community-onset bacteremia are less elucidated.Methods: During 96 randomly selected days between August 2006 and July 2007, a prospective study was conducted to analyze the risk factors of community-onset bacteremia among febrile adults who visited the emergency department (ED) of a medical center. Patients hospitalized in the 30 days prior to the study, patients experiencing consciousness alteration, and nursing facility residents were excluded.Results: The mean age of the 396 febrile adults enrolled in the study was 53.8 years (range, 18–95 years), and 60 (15.2%) patients had true bacteremia, with the predominance of monomicrobial Gram-negative pathogens (42 patients). In a multivariate analysis, several factors were independently associated with community-onset bacteremia, including an age of >65 years (odds ratio [OR], 2.81; 95% confidence interval [CI], 1.25–6.33), the presence of rigor (OR, 13.7; 95% CI, 4.47–42.0) or chills (OR, 6.04; 95% CI, 1.10–32.9), a body temperature >39.9 °C (OR, 2.68; 95% CI, 1.03–6.94), blood urea nitrogen >20 mg/dL (OR, 5.56; 95% CI, 2.03–15.7), a blood urea nitrogen/creatinine ratio >16 (OR, 2.29; 95% CI, 1.03–5.11), and thrombocytopenia (OR, 6.09; 95% CI, 1.84–20.0). After scoring each risk factor, a logistic regression model for the prediction of bacteremia was developed, and the area under the receiver operating characteristic curve was 0.91.Conclusions: Some easily determined clinical parameters were independently associated with community-onset bacteremia among febrile adults, and the most significant predictor was the presence of rigor. Although the proposed predictive model needs further validation, it may be of use for the early identification of bacteremic episodes in ED practice.

Antimicrobial resistance trends among 5608 clinical Gram-positive isolates in China: results from the Gram-Positive Cocci Resistance Surveillance program (2005–2010)

2012-04-23

Abstract: A total of 5608 clinical isolates of Gram-positive bacteria were collected from 12 teaching hospitals across China from 2005 to 2010. The minimum inhibitory concentrations (MICs) of 19 antimicrobial agents were determined by the agar dilution method at the central laboratory. Overall, the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MRSCoN) were 46.8% and 81.5%, respectively. Isolates from inpatients exhibited a higher rate of MRSA than that from outpatients (52.3% versus 26.2%, P < 0.001). The prevalence of MRSA in respiratory infections (67.5%) was higher than in other sources of infections (P < 0.001). A shift in vancomycin MICs from <0.5 to 1.0 μg/mL was observed during the 6-year period. In 2005, 70.5% of S. aureus isolates were inhibited at the vancomycin MIC of 0.5 μg/mL, while in 2010, 89% of the isolates were inhibited at the vancomycin MIC of 1 μg/mL. With the use of penicillin oral breakpoints, penicillin-resistant Streptococcus pneumoniae (PRSP) increased from 28.6% in 2005 to 59.5% in 2010 and varied among different age groups, with an average rate of 70.6% for children under 5 years old. Importantly, an obvious penicillin MIC right shift was observed from 0.032 to 4 μg/mL during the study period. Serotyping for the isolates from 2005 and 2010 indicated that the high rate of PRSP could be due to the increased prevalence of serogroup 19. The prevalence of vancomycin-resistant enterococci (VRE) increased from 0 in 2005 to 4.9% in 2010. Of the 27 VRE isolates, vanA gene was the most prevalent gene. During the study period, 97.9-100% of different species tested were susceptible to teicoplanin. Linezolid and tigecycline showed potent activities, and no resistant isolate was identified. In conclusion, although the prevalence of MRSA and MRSCoN remained stable over the 6 years, a sharp increase in the prevalence of PRSP was identified. In addition, MIC shifts, including the MICs of penicillin against S. pneumoniae and vancomycin against S. aureus, were observed. Continuous surveillance is warranted to evaluate the resistance trend of clinically important Gram-positive organisms in the future.

Predominance of pHK01-like incompatibility group FII plasmids encoding CTX-M-14 among extended-spectrum beta-lactamase–producing Escherichia coli in Hong Kong, 1996–2008

2012-04-23

Abstract: This study assessed the temporal changes in the molecular epidemiology of bacteremic Escherichia coli isolates producing CTX-M-14 in Hong Kong. Blood isolates from 1996 to 1998 (period 1, n = 50) and 2007 to 2008 (period 2, n = 117) were investigated by molecular methods. CTX-M–type ESBL was carried by 98.2% (164/167) of the isolates. In both periods, the CTX-M-9 group and CTX-M-14 allele were the predominant ESBL type. The major clones were found to change from ST68 and ST405 in period 1 to ST131, ST69, and ST12 in period 2. Among 65 CTX-M-14–producing plasmids investigated further, 54 had the FII replicon. Replicon sequence typing and plasmid polymerase chain reaction–restriction fragment length polymorphism showed that 79.6% (43/54) of the FII plasmid subset was similar to the completely sequenced plasmid, pHK01 (human urine, Hong Kong, 2004). These pHK01-like plasmids were found to have spread to the major clones (ST68, ST405, and ST131) and multiple singleton isolates of all 4 phylogenetic groups.

In vitro activity of cefditoren and other comparators against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis causing community-acquired respiratory tract infections in China

2012-04-23

Abstract: The aim of this study was to evaluate the in vitro activity of cefditoren and comparators against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis causing community-acquired respiratory tract infections (CARTIs). A total of 391 Streptococcus pneumoniae, 266 H. influenzae, and 76 M. catarrhalis were isolated from 10 centers located at 6 cities in China from January 2009 to May 2010. The microdilution method was used to determine minimum inhibitory concentrations (MICs). The pneumococci comprised 189 (48.3%) penicillin susceptible, 129 (33.0%) penicillin intermediate, and 73 (18.7%) penicillin resistant. Moxifloxacin and levofloxacin showed the highest activity (99.2% and 97.7%, respectively) against Streptococcus pneumoniae, followed by parenteral penicillin G (95.7%), cefditoren (83.1%) and amoxicillin–clavulanic acid (79.3%). Among the 266 H. influenzae isolates, 26 (9.8%) were ampicillin-resistant β-lactamase–producing strains and 24 (9.0%) were ampicillin-resistant β-lactamase–nonproducing strains (BLNAR). Most of antimicrobial agents demonstrated good activity (>97% susceptibility) against H. influenzae except ampicillin, cefuroxime, and cefaclor, which showed relatively lower activity (81.2%, 88.7%, and 88%, respectively). Cefditoren showed excellent activity with the lowest MIC50 and MIC90 (≤0.016/0.064 μg/mL) among all tested drugs, which is independent of β-lactamase production or ampicillin resistance. Cefditoren at a concentration of 0.5 μg/mL inhibited all BLNAR strains. Seventy of 76 isolates of M. catarrhalis produced β-lactamase. Cefditoren also showed excellent activity with MIC90 of 0.064 μg/mL against β-lactamase–nonproducing strains and 0.5 μg/mL against β-lactamase–producing strains. In conclusion, the excellent intrinsic activity of cefditoren suggests that it may be a good choice for the treatment of CARTIs caused by Streptococcus pneumoniae, H. influenzae, and M. catarrhalis in China, while the activity should be closely monitored.

Hepatic mucormycosis with abscess formation

Henry Su, George R. Thompson, Stuart H. Cohen — 2012-04-16

Abstract: We describe a case of hepatic mucormycosis with abscess, an uncommon presentation of mucormycetes infection. Our patient was initially treated with transcutaneous pigtail catheter placement, liposomal amphotericin B, and micafungin without improvement. The patient subsequently improved after hepatic segmentectomy and hemidiaphragm resection.

Dissemination of multidrug-resistant Escherichia coli in Korean veterinary hospitals

2012-04-20

Abstract: This study was performed to investigate the prevalence of rectal colonization with multidrug-resistant Escherichia coli in dogs hospitalized at veterinary hospitals in Korea and to assess the molecular epidemiologic traits of this organism. A total of 63 unique E. coli isolates obtained from the rectal swabs of hospitalized dogs were analyzed. Genes encoding CTX-M extended-spectrum β-lactamases (ESBLs) and AmpC enzymes were detected in 21 (33.3%) and 15 (23.8%) canine E. coli isolates, respectively. Twelve canine E. coli isolates harbored both the genes encoding the CTX-M and AmpC enzymes. Six ESBL-producing E. coli isolates also carried the rmtB gene. All 24 E. coli isolates producing CTX-M ESBL and/or CMY-2 were resistant to ciprofloxacin. Furthermore, mutations were found in the gyrA and the parC genes. In most cases, the bla genes of the CTX-M ESBL and AmpC enzymes and the rmtB gene were localized to incompatibility group F (IncF) plasmids. Possible small clonal outbreaks are suggested because some E. coli isolates recovered in the same veterinary hospital were identified as identical sequence types and showed identical banding patterns in repetitive sequence-based polymerase chain reaction. The horizontal transfer of IncF plasmids and the clonal transfer of E. coli strains are suggested to play a role in the dissemination of antimicrobial resistance genes, and this transfer may occur across host species (i.e., between humans and dogs).

Optimized serodiagnosis of Mycoplasma pneumoniae infections

2012-04-13

Abstract: Serologic methods are well established for the diagnosis of Mycoplasma pneumoniae infections in humans, but they are less sensitive than polymerase chain reaction (PCR). To improve their sensitivity, a new panel of antigens was tested. Compared with PCR results, up to 92% of PCR-positive patients were confirmed by our immunoblotting approach having a specificity between 92.6% and 100%.

Enterobacteriaceae producing the KPC-2 carbapenemase from hospital sewage

Xinzhuo Zhang, Xiaoju Lü, Zhiyong Zong — 2012-03-30

Abstract: Fifteen isolates with reduced susceptibility to meropenem were obtained from hospital sewage. They contained blaKPC-2 and belonged to multiple clones of Citrobacter freundii or Enterobacter cloacae. blaKPC-2 was commonly carried by self-transmissible plasmids with different EcoRI-restricted patterns. Tn2 was identified upstream of blaKPC-2, while ISKpn6 lay downstream. Hospital sewage could be an important reservoir of blaKPC-2 and warrants more studies.

Detection of KPC-2 and qnrS1 in clinical isolates of Morganella morganii from China

Jia Chang Cai, Wei Yang, Yan Yan Hu, Rong Zhang, Hong Wei Zhou, Gong-Xiang Chen — 2012-04-30

Abstract: Seven carbapenem-nonsusceptible Morganella morganii isolates, which have similar antibiotic susceptibility profiles, were isolated over a 5-month period. MICs of imipenem, meropenem, and ertapenem were 8, 1, and 0.25 to 0.5 μg/mL, respectively. Pulsed-field gel electrophoresis indicated that 6 isolates were indistinguishable or closely related. Carbapenem resistance can be transferred from M. morganii to Escherichia coli by conjugation. All M. morganii isolates and E. coli transconjugants produced KPC-2 and carried the qnrS1 gene. Production of KPC-2 mainly contributed to the carbapenem resistance in M. morganii. KPC-2–producing M. morganii clonally spread in a hospital in China.

Intrahospitalary dissemination of Klebsiella pneumoniae carrying blaDHA-1 and qnrB4 genes within a novel complex class 1 integron

2012-03-27

Klebsiella pneumoniae commonly causes community- and hospital-acquired infections, for which β-lactams and fluoroquinolones are the first-line therapeutic choices. However, resistance to these compounds has been reported, due to the production of plasmid-mediated AmpC or extended-spectrum beta-lactamases () and to mutations in gyrA and parC genes and/or to the acquisition of quinolone resistance determinants (qnr, aac(6′)-Ib-cr, qepA, etc.) ().

Antimicrobial activity of daptomycin in comparison to glycopeptides and other antimicrobials when tested against numerous species of coagulase-negative Staphylococcus

Helio S. Sader, Ronald N. Jones — 2012-06-01

Abstract: Coagulase-negative Staphylococcus spp. (CoNS) represent a major cause of bloodstream infections, especially in patients with prosthetic devices and intravenous catheters. We evaluated the activity of daptomycin in comparison to vancomycin and teicoplanin against a large collection of 22,024 CoNS isolates causing clinically significant infections from 283 medical centers over 9 years (2002–2010) and tested for susceptibility by broth microdilution methods against daptomycin and numerous comparators. Overall, daptomycin (MIC50/90, 0.25/0.5 μg/mL) inhibited 99.8% of CoNS at the susceptible breakpoint of ≤1 μg/mL and was 4- to 16-fold more active than vancomycin (MIC50/90, 1/2 μg/mL; >99.9% susceptible). All species showed ≥99.6% susceptibility to daptomycin, except Staphylococcus auricularis (95.1%), S. capitis (99.0%), S. warneri (98.8%), and S. sciuri. S.sciuri represented only 0.2% of the collection (46 strains) and exhibited decreased susceptibility to daptomycin (MIC50/90, 1/2 μg/mL; 71.7% susceptible). In contrast, S. sciuri exhibited high susceptibility to vancomycin and teicoplanin (highest MIC at 2 μg/mL for both drugs). In summary, daptomycin exhibited species-specific activity among CoNS, especially versus S. sciuri. No correlation between decreased susceptibility to daptomycin and the glycopeptides tested was observed.