Diagnostic Microbiology & Infectious Disease - Articles in Press

Identification of genetic recombination between Acinetobacter species based on multilocus sequence analysis - Corrected Proof

Dae Hun Kim, Young Kyoung Park, Ji Young Choi, Kwan Soo Ko — 2012-05-18

Abstract: During multilocus sequence analysis of Acinetobacter calcoaceticus–Acinetobacter baumannii complex, we identified the evidence of recent genetic recombination between 2 Acinetobacter species. While 3 isolates belonged to A. nosocomialis based on 16S rRNA, gyrB, fusA, gdhB, and rplB gene sequences, they showed close relationships with Acinetobacter genomic species ‘close to 13TU’ in rpoB, recA, cpn60, rpoD, and gltA gene trees.

Multidrug resistance among Acinetobacter spp. in the USA and activity profile of key agents: results from CAPITAL Surveillance 2010 - Corrected Proof

2012-05-14

Abstract: Multidrug resistance among Acinetobacter spp. leaves few effective antibiotic options for treatment. To monitor antibiotic resistance in Acinetobacter spp., the US CAPITAL 2010 Surveillance data were evaluated by patient demographics, specimen source, and hospital ward. Isolates (N=514) were collected from 65 sites across the USA and Puerto Rico. Isolates were centrally tested for susceptibility to carbapenems and key antimicrobials by broth microdilution. Colistin was the most effective agent tested, with 95% susceptibility. The overall susceptibility of Acinetobacter spp. was low (39% for piperacillin/tazobactam, 41% for levofloxacin, 45% for ceftazidime, 47–51% for the carbapenems, and 58% for tobramycin). Multidrug resistance (MDR), defined as resistance to ≥3 antimicrobial agent groups, was detected in 54% of the isolates. MDR isolates were most common among elderly patients (65%), lower respiratory tract isolates (62%), and inpatient/intensive care unit isolates (54–58%). These data update trends in the distribution and prevalence of the MDR phenotype in Acinetobacter spp.

Assessment of the mosaic structure in the Helicobacter pylori cagA gene 3′-region using an improved polymerase chain reaction–based assay - Corrected Proof

Hans-Jürg Monstein, Anna Ryberg, Anneli Karlsson — 2012-05-11

Abstract: The mosaic structure of the cagA gene has been suggested to affect Helicobacter pylori CagA–associated pathogenesis. An improved polymerase chain reaction assay allowed for a rapid and detailed molecular analysis of the cagA gene 3′-region in a single amplification step, followed by amplicon sequencing using universal M13 and T7 sequencing primers.

Activity of telavancin compared to other agents against coagulase-negative staphylococci with different resistotypes by time kill - Corrected Proof

Gengrong Lin, Glenn A. Pankuch, Peter C. Appelbaum, Klaudia Kosowska-Shick — 2012-05-10

Abstract: Among 10 coagulase-negative staphylococci, telavancin, quinupristin/dalfopristin, and tigecycline were the most potent antimicrobials. Telavancin exhibited bactericidal effect to 9 strains out of 10 tested at 4× MIC after 24 h of exposure similar to those of vancomycin and daptomycin. By contrast, linezolid was mainly bacteriostatic and teicoplanin was bactericidal to 7 strains tested at 4× MIC after 24 h.

Comparison of five diagnostic modalities for direct detection of Borrelia burgdorferi in patients with early Lyme disease - Corrected Proof

2012-05-09

Abstract: Lyme disease, the most commonly reported tick-borne infection in North America, is caused by infection with the spirochete Borrelia burgdorferi. Although an accurate clinical diagnosis can often be made based on the presence of erythema migrans, in research studies microbiologic or molecular microbiologic confirmation of the diagnosis may be required. In this study, we evaluated the sensitivity of 5 direct diagnostic methods (culture and nested polymerase chain reaction [PCR] of a 2-mm skin biopsy specimen, nested PCR and quantitative PCR (qPCR) performed on the same 1-mL aliquot of plasma and a novel qPCR–blood culture method) in 66 untreated adult patients with erythema migrans. Results of one or more of these tests were positive in 93.9% of the patients. Culture was more sensitive than PCR for both skin and blood, but the difference was only statistically significant for blood samples (P<0.005). Blood culture was significantly more likely to be positive in patients with multiple erythema migrans skin lesions compared to those with a single lesion (P=0.001). Positive test results among the 48 patients for whom all 5 assays were performed invariably included either a positive blood or a skin culture. The results of this study demonstrate that direct detection methods such as PCR and culture are highly sensitive in untreated adult patients with erythema migrans. This enabled microbiologic or molecular microbiologic confirmation of the diagnosis of B. burgdorferi infection in all but 4 (6.1%) of the 66 patients evaluated.

Molecular characterization of fluoroquinolone-resistant Mycobacterium tuberculosis clinical isolates from Shanghai, China - Corrected Proof

2012-05-07

Abstract: China is one of the countries with the highest prevalence of fluoroquinolone-resistant (FQr) Mycobacterium tuberculosis. Nevertheless, knowledge on the molecular characterization of the FQr M. tuberculosis strains of this region remains very limited. This study was performed to investigate the frequencies and types of mutations present in FQr M. tuberculosis clinical isolates collected in Shanghai, China. A total of 206 FQr M. tuberculosis strains and 21 ofloxacin-sensitive (FQs) M. tuberculosis strains were isolated from patients with pulmonary tuberculosis in Shanghai. The phenotypic drug susceptibilities were determined by the proportion method, and the mutations inside quinolone resistance–determining region (QRDR) of gyrA and gyrB genes were identified by DNA sequence analyses. Among 206 FQr M. tuberculosis strains, 44% (90/206) were multidrug-resistant isolates and 39% (81/206) were extensively drug–resistant isolates. Only 9% (19/206) were monoresistant to ofloxacin. In total, 79.1% (163/206) of FQr isolates harboured mutations in either gyrA or gyrB QRDR. Mutations in gyrA QRDR were found in 75.7% (156/206) of FQr clinical isolates. Among those gyrA mutants, a majority (75.6%) harboured mutations at amino acid position 94, with D94G being the most frequent amino acid substitution. Mutations in gyrA QRDR showed 100% positive predictive value for FQr M. tuberculosis in China. Mutations in gyrB were observed in 15.5% (32/206) of FQr clinical isolates. Ten novel mutations were identified in gyrB. However, most of them also harboured mutations in gyrA, limiting their contribution to FQr resistance in M. tuberculosis. Our findings indicated that, similar to other geographic regions, mutations in gyrA were shown to be the major mechanism of FQr resistance in M. tuberculosis isolates. The mutations in gyrA QRDR can be a good molecular surrogate marker for detecting FQr M. tuberculosis in China.

Evaluation of commercial screening tests and blot assays for the diagnosis of Lyme borreliosis - Corrected Proof

2012-05-07

Abstract: The performance of 4 screening tests and 10 blot assays for the serologic diagnosis of Lyme borreliosis in a Belgian population was evaluated. A total of 196 sera were tested: 36 Lyme borreliosis at different stages of the disease, 50 healthy blood donors, and 110 representing various clinical circumstances. The DiaSorin Liaison and Euroimmun Anti-Borrelia screening tests were evaluated. The tested blot assays were Virotech Borrelia LINE tests WE222, WE225, and WE224, as well as Mikrogen recomLine Borrelia and Viramed ViraStripe. The specificity of IgG was acceptable for the different assays. For IgM, DiaSorin Liaison Borrelia IgM Quant, Mikrogen recomLine, and Viramed ViraStripe lacked specificity. Interestingly, a higher rate of falsely reactive samples was observed in the group of patients suffering from malaria. Serological diagnosis of Lyme borreliosis remains challenging; assays should be evaluated in the population where they are intended to be used.

Kinetics of CMV seroconversion in a Swiss pregnant women population - Corrected Proof

Gregory T. Maine, René Stricker, Reto Stricker — 2012-04-30

Abstract: Retrospective evaluation of the kinetics of cytomegalovirus (CMV) seroconversion with CMV IgM, IgG, and IgG avidity assays, in a Swiss pregnant women population, has shown that the current published CMV serologic diagnostic algorithms were valid and fit for use. In 19% of the cases analyzed, CMV-specific IgM was detected before IgG.

Isolation of a capnophilic Escherichia coli strain from an empyemic patient - Corrected Proof

2012-04-30

Empyema is an accumulation of pus in the pleural cavity between the lungs and the chest wall. This rare but serious condition is most commonly caused by infection, and antibiotic therapy is the most common form of treatment. Despite the wide availability of novel antibiotics and improved diagnostic tools, empyema remains an important cause of morbidity and mortality (). Identification of bacteria present in the pus could facilitate the targeting of treatment strategies for empyema and help resolve infections more quickly.

Evaluation of the usefulness of six commercial agglutination assays for serologic diagnosis of toxoplasmosis - Corrected Proof

2012-04-27

Abstract: Six agglutination tests for detecting Toxoplasma gondii–specific antibodies (immunoglobulin G or M) in serum were performed and compared. In total, 599 sera were examined using direct and indirect agglutination assays. Sensitivity varied from 93.7% to 100% and specificity from 97.1% to 99.2%. In a selected population with interfering diseases, the percentage of false positives ranged from 4.3% to 10.9%. Although an overall agreement of 100% was found for chronic toxoplasmosis, sensitivity for the detection of confirmed acute toxoplasmosis ranged from 86.4% to 97.3%. Regarding the large variability in terms of the performance of the 6 assays, tests based on the hemagglutination principle were found to be better than the other agglutination tests for all the panels evaluated, meaning that they could be used as qualitative or semiquantitative low-cost screening assays.

Clinical value of whole-blood interferon-gamma assay in patients with suspected pulmonary tuberculosis and AFB smear- and polymerase chain reaction–negative bronchial aspirates - Corrected Proof

2012-04-27

Abstract: Combining a polymerase chain reaction (PCR) test with bronchoscopy is frequently performed to allow a rapid diagnosis of smear-negative pulmonary tuberculosis (PTB). However, limited data are available concerning clinical judgment in patients with suspected PTB and AFB smear- and PCR-negative bronchial aspirates (BA). The present study evaluated the usefulness of whole-blood QuantiFERON-TB Gold In-Tube (QFT) testing in these patients. Of 166 patients with suspected PTB who had undergone bronchoscopy because of smear-negative sputum or inadequate sputum production, 93 (56%) were diagnosed with culture-positive PTB. Seventy-four patients were either AFB smear- or PCR-positive. In the 75 patients whose BA AFB smear and PCR results were both negative, 19 were finally diagnosed with PTB by culture. The QFT test had a negative predictive value of 91% for PTB. The QFT test may be useful for excluding PTB in patients with suspected PTB whose BA AFB smear and PCR results are both negative.

Update: The diagnosis and management of dengue virus infection in North America - Corrected Proof

William F. Wright, Bobbi S. Pritt — 2012-04-27

Abstract: Dengue is a mosquito-transmitted infection that poses significant global health risks for travelers and individuals living in the tropics and subtropics. The reported global incidence has increased dramatically in the past century, with dengue now ranking as the most common cause of febrile illness in travelers. While sporadic cases have been reported within the southern United States since 1980, autochthonous outbreaks have now been described in Hawaii, St. Croix (US Virgin Islands), along the Texas–Mexico border, and, most recently, in Key West, Florida. Although many infections are mild or asymptomatic, 5–10% of patients may experience hemorrhagic disease, with shock and even death. Laboratory identification commonly involves serologic and nucleic acid amplification methods. Due to rising incidence worldwide, physicians should be familiar with the clinical manifestations, laboratory diagnosis, and management of this illness.

Evaluation of BACTEC Plus aerobic and anaerobic blood culture bottles and BacT/Alert FAN aerobic and anaerobic blood culture bottles for the detection of bacteremia in ICU patients - Corrected Proof

2012-04-27

Abstract: Blood culture is the most valuable laboratory test for the diagnosis of bacteremia and sepsis. The BACTEC FX and BacT/Alert 3D automated blood culture systems are commonly used in Korean health care facilities. A controlled clinical evaluation of the resin-containing BACTEC Plus aerobic (BA) and anaerobic (BN), and the charcoal-containing FAN aerobic (FA) and anaerobic (FN) bottles using blood from intensive care unit (ICU) patients was designed. The performances of these 2 systems with media containing particle absorbing antimicrobial agents were evaluated using the culture positivity rate and time to detection (TTD). TTD was collected using data management systems, either the Epicenter (BD Diagnostic Systems) or the hospital laboratory information system. A total of 1539 four-bottle sets were collected from 270 patients in medical and surgical ICUs. Blood culture samples included 1539 bottles each of BA, BN, FA, and FN, and yielded 113 (7.3%), 90 (5.8%), 104 (6.8%), and 80 (5.2%) positive bacterial or fungal isolates, respectively. There were significant differences between the resin-containing BA and BN samples in culture positivity and also between the charcoal-containing FA and FN samples, especially for Escherichia coli (25/27 versus 17/27, P < 0.05) and Acinetobacter baumannii (14/15 versus 7/15, P < 0.05). Significantly shorter recovery time was observed in BACTEC Plus aerobic bottles than in FAN aerobic bottles (17.2 and 24.7 h, respectively) (P < 0.001).

Detection of Mycoplasma pneumoniae and Chlamydophila pneumoniae directly from respiratory clinical specimens using a rapid real-time polymerase chain reaction assay - Corrected Proof

Maureen H. Diaz, Jonas M. Winchell — 2012-04-27

Abstract: We developed a rapid real-time polymerase chain reaction assay for detecting Mycoplasma pneumoniae and Chlamydophila pneumoniae directly from respiratory specimens. This procedure provides over 5 times faster results compared to existing methods while maintaining equivalent detection rates for specimens containing limited target organisms.

Detection of type-specific antibodies to HSV-1 and HSV-2: comparative analysis of a chemiluminescence immunoassay with a conventional ELISA - Corrected Proof

2012-04-26

Abstract: Type-specific serologic tests for human herpes simplex virus (HSV) are critically important for sexually transmitted disease evaluation. We compared the LIAISON® HSV-1 and HSV-2 Type Specific assays relative to an established commercial ELISA. The overall agreement of the chemiluminescence immunoassay versus the ELISA assay was 99.6% (HSV-1) and 100% (HSV-2). The LIAISON® methodology has several advantages.

Emergence of carbapenem-resistant Enterobacteriaceae isolates in the Moroccan community - Corrected Proof

2012-04-23

Carbapenems are often the recommended treatment for serious infections caused by extended- spectrum β-lactamase (ESBL)–producing Enterobacteriaceae or high-level AmpC-producing Enterobacteriaceae activity. However, resistance to carbapenems, resulting from carbapenemase production, reduces the possibility of treating infections of multidrug-resistant strains. Carbapenemase-producing Enterobacteriaceae have been reported increasingly worldwide and are becoming a major clinical and public health concern (). Recently, the detection of carbapenemase OXA-48 and NDM-1–producing Enterobacter cloacae and Klebsiella pneumoniae was reported in Moroccan hospitals. In addition, the occurrence of the OXA-48 producer was also reported in the environment in Morocco (). In this study, we report the recent emergence of carbapenems resistance among Enterobacteriaceae species in the community settings.

Optimization of a rapid diagnostic test for detection of group B streptococcus from antepartum patients - Corrected Proof

Jonathan P. Faro, Karen Bishop, Gerald Riddle, Allan Katz, Sebastian Faro — 2012-04-23

Abstract: We analyzed the performance of a new rapid diagnostic test for use in determining group B streptococcus colonization in pregnancy. Vaginal–rectal specimens were compared by the rapid test, a commercial laboratory culture result, and an in-house culture. Of 150 patient samples, 72 were positive by the rapid test, giving a prevalence of 48.0% versus 24.7% by traditional culture. Characterization of these results showed cross-reactivity with Enterococcus. The addition of bacitracin reduced this interference, and when reanalyzed, a colonization rate of 31.3% was found (P = 0.3961, chi-square), as well as a sensitivity of 100% (95% confidence interval [CI] 89.1–100) and a specificity of 93.6% (95% CI 86.9–97.2). The addition of bacitracin greatly improves the reliability of this diagnostic test and demonstrates a novel approach to reduce interference. An accurate determination of the test's sensitivity and specificity, however, awaits enrollment of the remaining subjects.

Sensitivity of QuantiFERON-TB GOLD In-Tube for diagnosis of recent versus remote M. tuberculosis infection - Corrected Proof

Jemianne Bautista, Niaz Banaei — 2012-04-23

Abstract: The sensitivity of QuantiFERON-TB GOLD In-Tube was measured in 104 subjects with recent (≤2 years) and remote Mycobacterium tuberculosis infection using tuberculin skin test conversion as the reference standard. The sensitivity was not significantly different between the 2 groups (33% versus 20%, P = 0.3). This finding suggests interferon-γ release assays may not be more sensitive for diagnosis of recent than remote infection. Longitudinal studies are needed to validate this finding.

Methicillin-resistant Staphylococcus aureus ST80-IV clone in children from Jordan - Corrected Proof

Wissam Khalil, Fuad Hashwa, Asem Shihabi, Sima Tokajian — 2012-04-20

Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of infections that are becoming increasingly difficult to combat because of emerging resistance. In this study, 103 S. aureus, 41 MRSA and 62 methicillin-sensitive Staphylococcus aureus isolates, were collected from children in Jordan. Genotyping based on spa and multilocus sequence typing (MLST) revealed 48 different spa types and identified distinct allelic profiles or STs, with the majority belonging to ST80. Pulsed-field gel electrophoresis (PFGE) of 15 different spa types revealed 8 different PFGE types, while SCCmec showed the predominance (53%) of subtype IV. Clustering SCCmec along with MLST revealed that ST80-MRSA-IV was the dominant type. Results obtained suggest that a significant amount of clonal spread is occurring in Jordan. The mechanism of spread of the ST80-IV clone is not known, and control measures are needed to reduce further spread of this or of other clones among children in Jordan.

Chronic fungal meningitis caused by Aureobasidium proteae - Corrected Proof

2012-04-16

Abstract: We present a case of chronic meningitis due to the mold Aureobasidium proteae. Clinical features, the disease course, as well as the diagnostic methods and optimal treatment options are discussed. This case confirms the neuroinvasiveness of A. proteae and introduces it as a new human pathogen.

Characterization of ST80 Panton-Valentine leukocidin-positive community-acquired methicillin-resistant Staphylococcus aureus clone in Tunisia - Corrected Proof

Mouna Ben Nejma, Maha Mastouri, Besma Bel Hadj Jrad, Mohamed Nour — 2008-04-04

Abstract: The spread of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has been reported in communities worldwide. In this study, we characterized 64 Tunisian CA-MRSA by agr typing, polymerase chain reaction assay for 20 virulence genes, staphylococcal chromosomal cassette mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and protein A gene (spa) typing. All our isolates were lukS-PV-lukF-PV positive, etd positive, and edin positive. They harbored SCCmec type IV and belonged to agr group 3. PFGE typing showed that our isolates were distributed in 11 different pulsotypes. spa typing and MLST, performed with isolates representative of each PFGE pattern, revealed that all isolates had a unique spa type (t044) and a common sequence type (ST80). The isolates showed susceptibility to the majority of antibiotics, and resistance to kanamycin, erythromycin, and tetracycline, but intermediate resistance to fusidic acid. Full analysis of our results revealed that our isolates were nonmultiresistant and belonged to a single clonal type ST80.

WITHDRAWN: Selection of a surrogate β-lactam testing agent for initial susceptibility testing of doripenem, a new carbapenem - Corrected Proof

Ronald N. Jones, Helio S. Sader, Thomas R. Fritsche, Michael J. Janechek — 2007-10-05

This article has been withdrawn consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

WITHDRAWN: Yersinia enterocolitica identification in stool samples using real-time PCR - Corrected Proof

Zheng HaoXuan, Wang JiDe, Zhang MingJun, Sun Yong, Jiang Bo — 2007-06-08

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy