Pelvic Abscess Secondary to Mycoplasma Hominis after Vaginal Laceration

BACKGROUND

Mycoplasma hominis frequently colonizes the urogenital and respiratory tracts of healthy individuals. It has also been associated with genitourinary tract and extragenital syndromes.

CASE

We present a 14-year-old girl who developed a pelvic abscess secondary to M. hominis after a vaginal laceration during sexual intercourse. Despite drainage and broad-spectrum antimicrobial therapy, the patient remained symptomatic until M. hominis was identified and specific therapy instituted.

SUMMARY AND CONCLUSION

Health care providers need to be aware of the potential for M. hominis as a causal agent in patients who present with pelvic abscesses after vaginal trauma. This case highlights the challenges that exist in the diagnosis and treatment of M. hominis, because bacterial cultures are often negative and empiric antimicrobial agents do not provide adequate antimicrobial coverage.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children

BACKGROUND

Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain.

METHODS

A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional.

CONCLUSIONS

These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Routine pathologic examination of tonsillectomy specimens: A 10-year experience at a tertiary care children's hospital

OBJECTIVE

To review histopathologic diagnoses from tonsillectomy specimens and determine whether routine pathologic exam is necessary.

METHODS

Pathology reports of patients undergoing tonsillectomy from 2005 to 2014 at our pediatric tertiary care hospital were reviewed. Histopathologic diagnoses were recorded with special attention to identification of malignancy.

RESULTS

A total of 8807 paired tonsil specimens were sent to pathology over a 10-year course. Gross analysis was performed on all. Microscopic histopathologic analysis was performed on 612 (6.95%) specimens with all but one demonstrating strictly reactive lymphoid hyperplasia. The single specimen (0.16%) demonstrated follicular hyperplasia with focal necrotizing granulomatous lymphadenitis without organisms identified on special staining. The surgeon requested pathologic diagnosis to rule out lymphoma in 4 of 8087 (0.05%) of the specimens. No malignancies were identified. The approximate charges for gross examination of a paired tonsillectomy specimen and microscopic examination were $136.10 and $294.54, respectively. Over the 10 year period of the study, total charges were estimated at $1,115,340 (gross) and $180,258 (microscopic).

DISCUSSION

Microscopic analysis of tonsil specimens is unlikely to identify abnormal pathology that changes patient management. This study suggests that neither gross nor microscopic pathologic examination of tonsillectomy specimens is necessary on a routine basis. Histologic analysis of tonsils should be requested only on a case by case basis when clinical suspicion for malignancy is high. Avoiding routine pathologic exam of tonsils may be cost effective and medically safe.

Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention Clinical Practice Guidelines: Diagnosis of Tuberculosis in Adults and Children

BACKGROUND

Individuals infected with Mycobacterium tuberculosis (Mtb) may develop symptoms and signs of disease (tuberculosis disease) or may have no clinical evidence of disease (latent tuberculosis infection [LTBI]). Tuberculosis disease is a leading cause of infectious disease morbidity and mortality worldwide, yet many questions related to its diagnosis remain.

METHODS

A task force supported by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence. The evidence was then used as the basis for recommendations about the diagnosis of tuberculosis disease and LTBI in adults and children. The recommendations were formulated, written, and graded using the Grading, Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-three evidence-based recommendations about diagnostic testing for latent tuberculosis infection, pulmonary tuberculosis, and extrapulmonary tuberculosis are provided. Six of the recommendations are strong, whereas the remaining 17 are conditional.

CONCLUSIONS

These guidelines are not intended to impose a standard of care. They provide the basis for rational decisions in the diagnosis of tuberculosis in the context of the existing evidence. No guidelines can take into account all of the often compelling unique individual clinical circumstances.

Failure of the Sterile Air-Flow Component of a Protected Environment Detected by Demonstration of Chaetomium Species Colonization of Four Consecutive Immunosuppressed Occupants

Four bone marrow transplant recipients consecutively occupying the same room on our Oncology-Hematology Special Care Unit (OHSCU) became colonized with Chaetomium species between January and April, 1987. These patients, aged 27 to 43 years, were immunocompromised as a result of intensive chemotherapy, and were consequently at increased risk for development of invasive fungal infection. At the time of Chaetomium colonization, all patients were febrile, two had transient new infiltrates on chest x-ray, and three were receiving amphotericin B therapy. Subsequent environmental cultures revealed Chaetomium contamination of the OHSCU air-handling system, including the HEPA (high-efficiency particulate air) filters in seven of the nine rooms comprising the unit. Because fungal colonization of HEPA filters used to create a “protective environment” for immunocompromised patients can occur and can serve as a source for patient infections, guidelines concerning proper surveillance of these HEPA filters should be established. We suggest that before a new patient enters a “protected” room, the clean side of the HEPA filter should be cultured. If fungi are recovered from that culture, we would recommend changing the filter.

Multiclonal methicillin-resistant Staphylococcus aureus (MRSA) outbreak and its control after use of the Veterans Affairs (VA) MRSA bundle in a VA long-term care facility, 2004-2014

A multiclonal methicillin-resistant Staphylococcus aureus (MRSA) outbreak with 91 infections occurred in our Veterans Affairs (VA) community living center over 46 months. Both similar and unique strains were shown by repetitive polymerase chain reaction to contribute to the outbreak, including 1 strain causing infections over a 33-month period. Most infections were soft tissue infections (67%). For 21 months after the initiation of the VA MRSA bundle, no infections were identified, and low rates of infection have been sustained an additional 4 years. The average annual rate of MRSA infection decreased by 62% (P < .001) from 0.6 per 1,000 resident days for 4 years prior to the bundle implementation to 0.09 per 1,000 resident days for 4 years after the bundle implementation.

A 66-year-old woman with fever, cough, and a tongue lesion

A 66-year-old woman presented with acute onset of fever, chills, and productive cough associated with right-sided chest pain. During a recent hospitalization for dyspnea, she had been diagnosed with Coombs-positive autoimmune hemolytic anemia and had been taking a tapering dose of prednisone starting approximately 6 weeks prior to admission. In the interim, her dyspnea had resolved on treatment with steroids. At the time of presentation, her prednisone dose was 40 mg. Additional medical history included VTE, for which the patient was receiving anticoagulation therapy, and steroid-induced diabetes mellitus. Many years earlier, she had been treated for TB in her home country. The patient had immigrated to Queens, New York, from a Nepalese village 8 years prior. While still in Nepal, she had worked on a farm and had been in close proximity to cows. In Queens, she lived with her family in a house with a small garden but had no pets. Recent travel included a visit to Nepal 9 months ago and a trip to Syracuse, New York, one month prior to presentation. She was a never smoker and did not consume alcohol.

Management of Complicated Appendicitis and Comparison of Outcome with Other Primary Sites of Intra-abdominal Infection: Results of a Trial Comparing Ertapenem and Piperacillin-Tazobactam

A post-hoc analysis of data from a trial of complicated intra-abdominal infection was performed to compare the demographic and disease characteristics of patients with complicated appendicitis to those whose primary infection involved other intra-abdominal sites, assess the impact of site of primary infection on outcome, and compare the efficacy and safety of ertapenem 1 g daily with piperacillin-tazobactam 3.375 g every 6 h for treatment of complicated appendicitis. Compared with patients who had primary infection of the colon or another site in the abdomen, patients with complicated appendicitis were younger, had less severe disease (based on lower APACHE II score and lower proportion with generalized peritonitis), and were less likely to be managed by percutaneous drainage of an abscess or to have a postoperative infection. Patients with complicated appendicitis were more likely to have a favorable outcome than were patients with infection of the colon (OR, 3.02; 95% CI, [1.54-5.901; P = .001). At the test-of-cure assessment, 109/123 (88.6%) microbiologically evaluable patients with complicated appendicitis who received ertapenem and 102/113 (90.3%) who received piperacillin-tazobactam had a favorable combined clinical and microbiologic outcome. The frequency and severity of drug-related adverse events were similar in the two treatment groups.

Pregnancy rates at Days 2 and 14 and estimated embryonic loss rates prior to day 14 in normal and subfertile mares

Pregnancy rates at Days 2 and 14 postovulation were determined for 15 normal mares and 15 subfertile mares. Embryonic loss rates were estimated by the difference in the Day 2 and Day 14 pregnancy rates. Mares were artificially inseminated with the pooled ejaculates from three stallions, and the embryonic vesicle was detected with ultrasonography at Days 9, 10, 12 and 14. Mares were short-cycled with prostaglandin F(2) alpha (PGF(2alpha)) and rebred to the same stallions, and the Day 2 pregnancy rates were determined by recovery of cleaved ova (embryos) from the surgically excised oviducts. Significantly more (P < 0.01) normal versus subfertile mares were pregnant at Day 14 (12 15 vs 3 15 ). There was no significant difference in the Day 2 pregnancy rate for normal versus subfertile mares (10 14 vs 11 14 ). There were no significant differences (P > 0.5) in the mean number of blastomeres per embryo or in the mean diameter of embryos recovered at Day 2 from normal or subfertile mares. The estimated embryonic loss rate was significantly lower (P < 0.01) for normal verusus subfertile mares (0 10 vs 8 11 ). Fertilization rates were similar for normal and subfertile mares; however, subfertile mares had a higher embryonic loss rate prior to Day 14 postovulation.

Survival of equine embryos transferred to normal and subfertile mares

To test the hypothesis that an abnormal uterine environment was a cause of early embryonic loss in subfertile mares, morphologically normal embryos were transferred to normal mares (n = 20) and subfertile mares (n = 20), and embryo survival rates were compared. Embryos were recovered nonsurgically at Days 7 to 8 postovulation and transferred surgically to normal and subfertile mares that had ovulated on the same day or within 2 d after a donor. Survival of transferred embryos was monitored by ultrasonography of the recipient mare's uterus from Day 9 through Day 28 postovulation. There were no significant differences (P > 0.5) in the embryo survival rates at Day 12 (11 20 vs 9 20 ) or Day 28 (10 20 vs 8 20 ) for normal or subfertile mares, respectively. The uterine environment of subfertile mares was apparently adequate to support the development of transferred embryos from Days 7 or 8 through Day 28 postovulation.

Multisite reproducibility of the broth microdilution method for susceptibility testing of Nocardia species

Antimicrobial susceptibility testing (AST) of clinical isolates of Nocardia is recommended to detect resistance to commonly used antimicrobial agents; such testing is complicated by difficulties in inoculum preparation and test interpretation. In this study, six laboratories performed repetitive broth microdilution testing on single strains of Nocardia brasiliensis, Nocardia cyriacigeorgica, Nocardia farcinica, Nocardia nova, and Nocardia wallacei. For each isolate, a total of 30 microdilution panels from three different lots were tested at most sites. The goal of the study was to determine the inter- and intralaboratory reproducibility of susceptibility testing of this group of isolates. Acceptable agreement (>90% agreement at ±1 dilution of the MIC mode) was found for amikacin, ciprofloxacin, clarithromycin, and moxifloxacin. After eliminating MIC values from single laboratories whose results showed the greatest deviation from those of the remaining laboratories, acceptable agreement was also found for amoxicillin-clavulanic acid, linezolid, minocycline, and tobramycin. Results showed unsatisfactory reproducibility of broth microdilution testing of ceftriaxone with N. cyriacigeorgica and N. wallacei, tigecycline with N. brasiliensis and N. cyriacigeorgica, and sulfonamides with N. farcinica and N. wallacei. N. nova ATCC BAA-2227 is proposed as a quality control organism for AST of Nocardia sp., and the use of a disk diffusion test for sulfisoxazole is proposed as a check of the adequacy of the inoculum and to confirm sulfonamide MIC results.

Use of interferon-gamma release assays in a health care worker screening program: experience from a tertiary care centre in the United States

BACKGROUND

Interferon-gamma release assays including the QuantiFERON-TB Gold In-Tube test (QFT-GIT [Cellestis Ltd, Australia]) may be used in place of the tuberculin skin test (TST) in surveillance programs for Mycobacterium tuberculosis infection control. However, data on performance and practicality of the QFT-GIT in such programs for health care workers (HCWs) are limited.

OBJECTIVES

To assess the performance, practicality and reversion rate of the QFT-GIT among HCWs at a tertiary health care institution in the United States.

METHODS

Retrospective chart review of HCWs at Central Arkansas Veterans Healthcare System (Arkansas, USA) who underwent QFT-GIT testing as a part of their employee screening between November 1, 2008 and October 31, 2009.

RESULTS

QFT-GIT was used to screen 3290 HCWs. The initial QFT-GIT was interpreted as positive for 129 (3.9%) HCWs, negative for 3155 (95.9%) and indeterminate for six (0.2%). Testing with QFT-GIT was repeated in 45 HCWs who had positive results on the initial test. The QFT-GIT reverted to negative in 18 (40.0%) HCWs, all of whom had negative TST status and initial interferon-gamma values of 0.35 IU⁄mL to 2.0 IU⁄mL.

CONCLUSION

The QFT-GIT test is feasible in large health care setting as an alternative to TST for M tuberculosis infection screening in HCWs but is not free from challenges. The major concerns are the high number of positive test results and high reversion rates on repeat testing, illustrating poor short-term reproducibility of positive QFT-GIT test results. These results suggest adopting a borderline zone between interferon-gamma values of 0.35 IU⁄mL to 2.0 IU⁄mL, and cautious clinical interpretation of values in this range.

Ejaculatory pattern of llamas during copulation

The objective of this study was to use transrectal digital palpation of urethral pulses to define the ejaculatory pattern of llamas during copulation. Five male llamas were palpated during 5 to 6 copulations each with receptive female llamas (n = 28 copulations). The time from first exposure of a male to a female until mounting was 0.7 +/- 1.1 min (mean +/- SD), time to the first intromission was 1.7 +/- 1.4 min, and time from initial mount to final dismount (copulation duration) was 21.7 +/- 7.8 min. A total of 121.9 +/- 61.0 urethral pulses per copulation (5.6 +/- 1.7 pulses/min) was palpated. During the first 3.9 +/- 3.7 min of copulation, urethral pulses (11.0 +/- 10.1 urethral pulses at 3.5 +/- 2.5 pulses/min) occurred randomly and were not associated with whole-body strains. After the first 4 min of copulation, urethral pulses occurred in a pattern of clusters of frequent urethral pulses associated with whole-body strains, alternating with intercluster intervals of infrequent urethral pulses without whole-body strains. Individual clusters were characterized by 4.3 +/- 2.7 urethral pulses at 16.7 +/- 4.5 pulses/min during strains, and intercluster intervals were characterized by 1.7 +/- 2.3 urethral pulses at 2.2 +/- 1.8 pulses/min. Each cluster of urethral pulses during a strain was preceded by 2.3 +/- 1.8 repositions of the male's hindlegs and by 38.1 +/- 20.8 pelvic thrusts. There were 18.5 +/- 10.6 clusters of urethral pulses accompanied by strains per copulation at 0.9 +/- 0.3 clusters/min. The 18 to 19 clusters of urethral pulses appeared to be individual ejaculations. Therefore, we hypothesize that llamas ejaculated 18 to 19 times during their 22-min copulations.

Ertapenem versus cefepime for initial empirical treatment of pneumonia acquired in skilled-care facilities or in hospitals outside the intensive care unit

The study presented here compared the efficacy and safety of ertapenem and cefepime as initial treatment for adults with pneumonia acquired in skilled-care facilities or in hospital environments outside the intensive care unit (ICU). Non-ventilated patients developing pneumonia in hospital environments outside the ICU, in nursing homes, or in other skilled-care facilities were enrolled in this double-blind non-inferiority study, stratified by APACHE II score (<or=15 vs >15) and randomized (1:1) to receive cefepime (2 g every 12 h with optional metronidazole 500 mg every 12 h) or ertapenem (1 g daily). After 3 days of parenteral therapy, participants demonstrating clinical improvement could be switched to oral ciprofloxacin or another appropriate oral agent. Probable pathogens were identified in 162 (53.5%) of the 303 randomized participants. The most common pathogens were Enterobacteriaceae, Streptococcus pneumoniae, and Staphylococcus aureus, isolated from 59 (19.5%), 39 (12.9%), and 35 (11.6%) participants, respectively. At the test-of-cure assessment 7-14 days after completion of all study therapy, pneumonia had resolved or substantially improved in 89 (87.3%) of 102 clinically evaluable ertapenem recipients and 80 (86%) of 93 clinically evaluable cefepime recipients (95% confidence interval for the difference, -9.4 to 11.8%), fulfilling pre-specified criteria for statistical non-inferiority. The frequency and severity of drug-related adverse events were generally similar in both treatment groups. In this study population, ertapenem was as well-tolerated and efficacious as cefepime for the initial treatment of pneumonia acquired in skilled-care facilities or in hospital environments outside the ICU.

Identification of Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species by repetitive-sequence-based PCR

The performance of repetitive-sequence-based PCR (rep-PCR) using the DiversiLab system for identification of Coccidioides species, Blastomyces dermatitidis, and Histoplasma capsulatum was assessed by comparing data obtained to colony morphology and microscopic characteristics and to nucleic acid probe results. DNA from cultures of 23 Coccidioides, 24 B. dermatitidis, 24 H. capsulatum, 3 Arthrographis, and 2 Malbranchea isolates was extracted using a microbial DNA isolation kit as recommended by Bacterial Barcodes, Inc. Rep-PCR and probe results agreed for 97.2% of the dimorphic fungi when > or =85% similarity was used as the criterion for identification. Two H. capsulatum isolates were not identified, but no isolates were misidentified. From 43 of those cultures (15 Coccidioides, 14 B. dermatitidis, 14 H. capsulatum, 3 Arthrographis, and 2 Malbranchea), DNA also was extracted using an IDI lysis kit, a simpler method. Rep-PCR and probe results agreed for 97.7% of the dimorphic fungi when a criterion of > or =90% similarity was used for identification. One H. capsulatum isolate could not be identified; no isolates were misidentified. Using > or =85% similarity for identification resulted in one misidentification. These data suggest that the DiversiLab system can be used to identify Coccidioides and B. dermatitidis and, possibly, H. capsulatum isolates.

Mycobacterium arupense sp. nov., a non-chromogenic bacterium isolated from clinical specimens

SeveralMycobacterium-like organisms related to theMycobacterium terraecomplex have been isolated from clinical samples. In the clinical microbiology laboratory, partial 16S rRNA gene sequencing (approximately the first 500 bp) rather than full 16S rRNA gene sequencing is often used to identifyMycobacteriumspecies. Partial 16S rRNA gene sequence analysis revealed 100 % similarity between 65 clinical isolates andMycobacteriumsp. MCRO 6 (GenBank accession no. X93032). Even after sequencing the nearly full-length 16S rRNA gene, closest similarity was only 99.6 % toMycobacterium nonchromogenicumATCC 19530T. Sequencing of the nearly full-length 16S rRNA gene, the 16S–23S internal transcribed spacer region and thehsp65gene did not reveal genotypic identity with the type strains ofM. nonchromogenicum,M. terraeorMycobacterium triviale. Although sequence analysis suggested that these clinical isolates represented a novel species, mycolic acid analysis by HPLC failed to distinguish them fromM. nonchromogenicum. Therefore, phenotypic analysis including growth characterization, antibiotic susceptibility testing and biochemical testing was performed. These strains from clinical samples should be recognized as representing a novel species of the genusMycobacterium, for which the nameMycobacterium arupensesp. nov. is proposed. The type strain is AR30097T(=ATCC BAA-1242T=DSM 44942T).

Comparison of real-time polymerase chain reaction using the Smart Cycler and the Gen-Probe amplified Mycobacterium tuberculosis direct test for detection of M. tuberculosis complex in clinical specimens

The performance of a real-time polymerase chain reaction (PCR) assay using the Smart Cycler instrument and a minor groove binding MGB Eclipse probe (Epoch Biosciences, Bothell, WA) for identification of Mycobacterium tuberculosis complex in acid-fast bacillus smear-positive and smear-negative clinical specimens was assessed by comparing results to the Amplified M. tuberculosis Direct Test (MTD) and mycobacterial culture plus clinical diagnosis. After initial testing, the overall sensitivity, specificity, and positive and negative predictive values of PCR for the 172 specimens submitted for mycobacterial culture were 86.3%, 100%, 100%, and 94.5%, respectively. These same values for MTD were 98.0%, 99.2%, 98.0%, and 99.2%. For 83 additional specimens, only MTD and PCR were performed; 5 specimens were positive and 78 were negative by both tests. The sensitivity of the PCR assay was improved by using different primers and probes. The time to a result for real-time PCR, starting with a decontaminated sample, was less than 3 h compared with 5-6 h for the MTD.

Clinical evaluation of repetitive sequence-based polymerase chain reaction using the Diversi-Lab System for strain typing of vancomycin-resistant enterococci

The reliability of the Diversi-Lab System, an automated method of microbial strain typing using repetitive sequence-based polymerase chain reaction (rep-PCR), was evaluated by comparing results with those obtained by pulsed-field gel electrophoresis (PFGE). Ninety-five clinical isolates of vancomycin-resistant enterococci (VRE; 13 groups, 2-17 isolates per group) sent to Associated Regional and University Pathologists (ARUP) Laboratories for typing were tested by both methods. Rep-PCR and PFGE results were concordant for 83 isolates: all 32 isolates in 6 of the groups and 51 of the 63 isolates in the other 7 groups. Clustering of the remaining 12 isolates differed. With the Diversi-Lab System, analysis is objective, and results are available in 4 h, compared with a more subjective analysis and a 2- to 3-day turnaround time for PFGE. The Diversi-Lab System may be a viable alternative to PFGE for typing VRE in clinical reference laboratories.

Evaluation of a (1->3)-beta-D-glucan assay for diagnosis of invasive fungal infections

The Fungitell assay (Associates of Cape Cod, Inc.) is a commercial test that detects (1-3)-beta-D-glucan (BG) and is intended for diagnosis of invasive fungal infections. To evaluate the Fungitell assay, we tested serum and plasma samples from healthy blood donors and from patients with blood cultures positive for yeast or bacteria. All 36 blood donors were BG negative, and 13 of 15 candidemic patients were BG positive. Of 25 bacteremic patients, 14 (10 with gram-positive bacteremia) were BG positive. One of the latter patients with Staphylococcus aureus bacteremia also had invasive candidiasis, based on histological findings in a tissue biopsy; therefore, the BG result was a true positive. The sensitivity, specificity, and positive and negative predictive values of the Fungitell assay, by patient, for these three groups were 93.3%, 77.2%, 51.9%, and 97.8%, respectively. We also performed the Fungitell assay on sera that had been tested for Aspergillus galactomannan or Histoplasma antigen. All six Histoplasma antigen-positive patients and 31 of 32 Aspergillus galactomannan-positive patients were also BG positive. BG results for the 10 Histoplasma antigen-negative and the 32 Aspergillus galactomannan-negative patients varied, but we were unable to confirm many of the results. Between-run coefficients of variance (CVs) for the assay ranged from 3.2% to 16.8%; within-run CVs were < or =4.8%. The correlation coefficient for an interlaboratory reproducibility study was 0.9892. Concentrations of hemoglobulin, bilirubin, and triglycerides that caused 20% interference were 588, 72, and 466 mg/dl, respectively. Our results suggest that the Fungitel assay may be most useful for excluding invasive fungal infection.

Use of the MGB Eclipse system and SmartCycler PCR for differentiation of Mycobacterium chelonae and M. abscessus

Although accurate in the identification of Mycobacterium species, partial 16S rRNA gene sequencing does not distinguish Mycobacterium chelonae from M. abscessus. Thus, we designed a SmartCycler PCR assay targeting the 16S-to-23S internal transcribed spacer (ITS) region with use of MGB Eclipse probes to distinguish each species. Comparison with PCR-restriction enzyme analysis of a 441-bp fragment of the hsp65 gene resulted in 100% correlation with 25 isolates of M. chelonae and 25 isolates of M. abscessus. ITS PCR performed on 90 consecutive isolates identified by partial 16S rRNA gene sequencing (26 isolates of the M. chelonae-M. abscessus complex and 64 remaining isolates, including Mycobacterium species, Nocardia species, and other aerobic actinomycetes) showed 100% specificity and sensitivity. The ITS PCR assay is accurate and specific, easy to perform, and a good supplemental test when using partial 16S rRNA gene sequencing to identify M. chelonae and M. abscessus.

Interpretive criteria for use of AccuProbe for identification of Mycobacterium avium complex directly from 7H9 broth cultures

Rapid identification of Mycobacterium avium complex (MAC) is possible by use of AccuProbe (Gen-Probe, San Diego, Calif.). To evaluate the reliability of the MAC AccuProbe for testing 7H9 cultures inoculated with broth from MGIT cultures positive for acid-fast bacilli or growth on a solid medium, we compared probe results to results obtained by sequencing a portion of the 16S rRNA gene. Isolates were sequenced if the MAC probe result was <100,000 relative light units (RLU) or if it was > or =100,000 RLU and the colony morphology was not classic or there were two colony types. For the 1,389 cultures tested in phase 1, conducted to evaluate cutoff values for the MAC probe in testing of 7H9 cultures inoculated with broth from MGIT cultures, the sensitivity and specificity of the MAC AccuProbe were 97.7% and 88.8%, respectively, according to the manufacturer's interpretive criteria (> or =30,000 RLU is positive). If the cutoff for a positive result were 80,000 RLU, the specificity would be 100% and the sensitivity 92.3%. Of the 344 isolates in phase 2, which was conducted to confirm the 80,000-RLU cutoff for a positive result and therefore included only isolates with a MAC probe result of < or =100,000 RLU, 13 of 16 with results of > or =30,000 but <80,000 RLU were identified as mycobacteria other than MAC, including five Mycobacterium tuberculosis complex isolates. These data support the use of 80,000 RLU as the cutoff for a positive result in testing of 7H9 broth cultures with the MAC AccuProbe.

Comparison of six methods of extracting Mycobacterium tuberculosis DNA from processed sputum for testing by quantitative real-time PCR

Six methods of extracting Mycobacterium tuberculosis DNA from sputum for testing by quantitative PCR were compared: Tris-EDTA (TE) buffer, PrepMan Ultra, 2% sodium dodecyl sulfate (SDS)-10% Triton X with and without sonication, Infectio Diagnostics, Inc. (IDI) lysing tubes, and QIAGEN QIAamp DNA mini kit; all included a 15-min boiling step. Pooled digested and decontaminated sputum was spiked with M. tuberculosis ATCC 27294. Each extraction method was repeated eight times. Quantitative PCR was performed on the Smart Cycler and Rotor-Gene 3000 using primers targeting an 83-bp fragment of IS6110. An minor grove binding Eclipse probe with a fluorescent label was used for detection. An internal control was included to detect amplification inhibition. The limit of detection of M. tuberculosis DNA was 0.5 fg with both instruments. Calculated DNA concentrations (picograms) extracted using IDI, PrepMan, QIAGEN, and TE were 42.8, 30.4, 28.2, and 7.4, respectively, when run on the Smart Cycler, and 51.7, 20.1, 14.9, and 8.6, respectively, when run on Rotor-Gene. All extractions using SDS/Triton X with or without sonication were inhibited. Of the extraction methods evaluated, IDI lysis tubes provided the greatest yield of mycobacterial DNA, and the procedure can be completed in less than 1 h versus 2.5-3 h for the QIAGEN extraction.

Repetitive-sequence-PCR-based DNA fingerprinting using the Diversilab system for identification of commonly encountered dermatophytes

The performance of repetitive-sequence-based PCR (rep-PCR) using the DiversiLab system for identification of dermatophytes commonly isolated in a clinical laboratory was assessed by comparing results to those of conventional tests (colony morphology, microscopic examination of slide cultures, and, for suspected Trichophyton species, use of additional media). Sixty-one cultures were tested in phase 1, the feasibility portion of the study; 64 additional cultures were tested in phase 2, the validation portion conducted to assess reproducibility and confirm accuracy. Discrepancies were resolved by repeating rep-PCR and conventional tests and, in phase 2, sequencing the internal transcribed spacers. After initial testing of the cultures in phase 1 (excluding one contaminated culture), agreement between conventional tests and rep-PCR was 90% (54 of 60). Agreement was 98.3% after resolution of discrepancies, and in all but one case the initial rep-PCR result was correct. After initial testing of cultures in phase 2 (excluding one discarded and one contaminated culture), agreement between rep-PCR and conventional testing was 88.7% (55 of 62). After discrepancies were resolved, agreement was 100%. Initial rep-PCR results were correct, except for one Microsporum canis culture containing two colony variants, which could not be initially identified by rep-PCR. The performance of the DiversiLab system for identification of the dermatophytes commonly encountered in a clinical mycology laboratory-Trichophyton mentagrophytes, Trichophyton rubrum, Trichophyton tonsurans, and M. canis-was excellent. Moreover, the DiversiLab system is technically simple and provides results in < 24 h once a pure culture is available for testing, which is considerably more rapid than conventional identification tests.

In vitro susceptibilities of aerobic and facultative Gram-negative bacilli isolated from patients with intra-abdominal infections worldwide: the 2003 Study for Monitoring Antimicrobial Resistance Trends (SMART)

OBJECTIVES

The SMART (Study for Monitoring Antimicrobial Resistance Trends) surveillance programme was begun in 2002 to monitor antimicrobial resistance trends among aerobic and facultative Gram-negative bacilli (GNB) isolated from intra-abdominal infections worldwide.

METHODS

In 2003, 74 medical centres from 23 countries collected isolates for testing. Antimicrobial susceptibility testing was performed using broth microdilution according to the NCCLS guidelines for MIC testing.

RESULTS

A total of 5658 aerobic and facultative GNB were isolated from intra-abdominal infections. Enterobacteriaceae composed 84% of the total isolates. Among the agents tested, the carbapenems were the most consistently active against the Enterobacteriaceae. E. coli was the most common isolate (46%), and the susceptibility rate to the quinolone (70-90% susceptible), cephalosporin (80-97% susceptible), aminoglycoside (77-100% susceptible) and carbapenem (99-100% susceptible) agents tested varied among geographic regions, with isolates from the Asia/Pacific region generally being the most resistant. Extended-spectrum beta-lactamases (ESBLs) were detected phenotypically in 9% of E. coli, 14% of Klebsiella spp., and 14% of Enterobacter spp. worldwide. ESBL producers generally had a more antibiotic-resistant profile than non-ESBL producers.

CONCLUSIONS

Antimicrobial resistance among GNB isolated from intra-abdominal infections is a problem worldwide, especially in the Asia/Pacific region. The carbapenems ertapenem, meropenem and imipenem are highly active in vitro against Enterobacteriaceae isolated from intra-abdominal sites, including organisms that produce ESBLs.

Clinical evaluation of the DiversiLab microbial typing system using repetitive-sequence-based PCR for characterization of Staphylococcus aureus strains

The DiversiLab System, which includes microfluidics-based detection, reagent kits, and software for data processing and analysis, is an automated method using repetitive sequence-based PCR (rep-PCR) for microbial strain typing. To assess the reliability of the DiversiLab System for strain characterization of Staphylococcus aureus, we tested clinical isolates sent to ARUP Laboratories for typing and compared results to those of pulsed field electrophoresis (PFGE) aided by the cluster analysis provided by BioNumerics software. spa typing was performed when the results of these two methods for an outbreak were not concordant. The study included 89 S. aureus isolates (65 mecA positive, 24 mecA negative) from 19 outbreaks (2 to 11 isolates/outbreak). The DiversiLab and PFGE-BioNumerics results were concordant for 15 of the 19 outbreaks. For the remaining four outbreaks, there was partial concordance between the two methods. spa typing results were the same as or more similar to rep-PCR results for three of those outbreaks and were more similar to PFGE results for one. With regard to performance, the DiversiLab system was considerably less labor intensive than PFGE and provided results in less than 24 h, compared with 2 to 3 days for PFGE. Additionally, the Web-based DiversiLab software provides standardized comparisons among isolates almost instantaneously and generates user-friendly, customized reports.

Antimicrobial susceptibility patterns in Pseudomonas aeruginosa: data from a multicenter Intensive Care Unit Surveillance Study (ISS) in the United States

The objectives of this study were to analyze susceptibility rates and patterns in Pseudomonas aeruginosa isolates from patients in intensive care units (ICU). A total of 2209 isolates in 1995/1996 and 2672 in 2001/2002 were tested at United States sites participating in the ICU Surveillance Study. In both periods, of the agents tested, amikacin was the most active and ciprofloxacin, the least. Resistance to common antipseudomonal agents tested increased from 1995/1996 to 2001/2002; the rise was least for amikacin (2%) and greatest for ciprofloxacin (16%). The proportion of isolates susceptible to all six antipseudomonal agents tested since 1996 decreased from 60.4% to 48.9% in 2001/2002. Examination of MIC distributions for the two periods showed that for some drugs, e.g. imipenem and ceftazidime, the populations of susceptible and resistant isolates remained distinct, although the resistant population increased. For other drugs, e.g. amikacin and piperacillin-tazobactam, the MIC distribution shifted upward over time. The categorical agreement between agents of the same or like classes for isolates tested in 2001/2002 was highest for ciprofloxacin and levofloxacin (93.2%, with 1.2% major errors) and lowest for the aminoglycosides (81.3%, with 10.2% major errors). We can conclude that resistance to antipseudomonal agents among ICU isolates of P. aeruginosa, especially fluoroquinolones, is increasing. The resistance rate for some antipseudomonal agents may not accurately reflect shifts in the MIC distribution curve.

Ertapenem as initial antimicrobial monotherapy for patients with chronic obstructive pulmonary disease hospitalized with typical community-acquired pneumonia

This report describes a post-hoc analysis of two large studies of typical community-acquired pneumonia (CAP) in hospitalized patients, focusing on demographics, disease characteristics, and outcome in patients with and without chronic obstructive pulmonary disease (COPD). In both studies, ertapenem 1 g IV daily was compared with ceftriaxone 1 g IV daily as initial antimicrobial therapy. Clinically improving patients could be switched to oral antibiotic therapy after 3 days. Of the 857 patients treated in both studies, 264 (31%) had COPD. The proportions of patients who were male, were >/=65 years of age, had a Pneumonia Severity Index of IV/V, or had Haemophilus influenzae isolated in a baseline culture were higher in patients with COPD. Streptococcus pneumoniae was the most common pathogen both in patients with and without COPD. Clinical response rates in assessable patients 7-14 days after completion of therapy for the combined treatment groups were 90% (187/208) for patients with COPD and 93% (424/456) for those without COPD (odds ratio 0.7 [95% CI, 0.4-1.2], P = 0.17). Of assessable COPD patients, 109/121 (90%) treated with ertapenem and 78/87 (90%) treated with ceftriaxone achieved a favorable clinical response (odds ratio 1.0 [95% CI, 0.6-1.8], P = 0.94). The outcome in patients with or without COPD was similar regardless of therapy. In patients with COPD as well as in the overall study population, the efficacy of ertapenem as initial antimicrobial monotherapy for patients with serious typical community-acquired pneumonia was comparable to that of ceftriaxone.

Evaluation of the ELVIS plate method for the detection and typing of herpes simplex virus in clinical specimens

This study was conducted to assess the reliability of a commercial enzyme-linked viral inducible system (ELVIS) (Diagnostic Hybrids, Inc., Athens, OH) for rapid detection and typing of herpes simplex virus (HSV). Results using ELVIS were compared to those of shell vial culture (SVC) and HSV detection with monoclonal antibodies and an immunoperoxidase stain plus typing with MicroTrak direct fluorescent antibodies (Trinity Biotech PLC, Wicklow, Ireland). Specimens yielding discrepant HSV results were tested by polymerase chain reaction (PCR); those with discrepant typing results were stained with Simulfluor (Chemicon, Temecula, CA). Of the 206 samples tested, 144 were negative and 54 were HSV-positive by both methods (agreement, 96.1%). Five specimens were positive by ELVIS but negative by SVC; 3 of these were positive and 2 were negative by HSV PCR. Both of the latter were the result of mechanical problems early in the study. Three specimens were positive by SVC but negative by ELVIS; all 3 were positive by HSV PCR. After resolution of discrepancies, the sensitivity and specificity for detection of HSV were 95.0% and 100% for SVC, respectively, and 95.0% and 98.6% for ELVIS. Of the 46 HSV-positive samples that were typed, 26 were called type 2 and 18 were type 1 by both methods (agreement, 95.7%). The 2 specimens with discrepant results were called HSV-2 by SVC, staining with MicroTrak, and HSV-1 with ELVIS; both of these were type 2 when stained with the Simulfluor reagent. ELVIS is a reliable alternative to SVC for rapid detection and typing of HSV.

Ertapenem versus ceftriaxone for the treatment of community-acquired pneumonia in adults: combined analysis of two multicentre randomized, double-blind studies

The efficacy and safety of ertapenem, 1 g once a day, for the treatment of community-acquired pneumonia (CAP) requiring parenteral therapy were compared with those of ceftriaxone, 1 g once a day, in 866 hospitalized adults randomized in two prospective, double-blind, multicentre studies. Patients were stratified according to Pneumonia Severity Index (< or = 3 or >3) or age (< or = 65 or >65 years). After > or = 3 days of parenteral antimicrobial therapy, patients who had clinically improved could be switched to oral co-amoxiclav. The median durations of parenteral, oral and total therapy in the 658 clinically evaluable patients, of whom 88% were switched to oral therapy, were 4, 7 and 12 days, respectively, in both treatment groups. The most common pathogen was Streptococcus pneumoniae, of which 79% (143/181) were penicillin susceptible and 3.3% (6/181; three in each treatment group) were penicillin resistant. Cure rates for the two treatments were equivalent: 91.9% for ertapenem and 92.0% for ceftriaxone (95% confidence interval for the difference, adjusted for strata: -4.5 to 4.4). Cure rates in the different severity and age strata and bacterial eradication rates for both treatment groups were also similar. The most common drug-related adverse events in both treatment groups were diarrhoea and mild-to-moderate elevations in aminotransferase levels. The results of these studies demonstrate that ertapenem, 1 g once a day, was highly effective therapy for CAP in hospitalized adults with moderate-to-severe disease.

Treatment of polymicrobial infections: post hoc analysis of three trials comparing ertapenem and piperacillin-tazobactam

The efficacy of ertapenem 1 g once a day for the treatment of polymicrobial complicated intra-abdominal, complicated skin/skin-structure and acute pelvic infections was compared with piperacillin-tazobactam 3.375 g every 6 h in a post hoc analysis of data from three large randomized double-blind trials. Of the 1,558 treated patients in the three trials, no pathogen was identified in 345 (22.1%), 423 (27.2%) had a monomicrobial infection and 790 (50.7%) had a polymicrobial infection. At the test-of-cure assessment, there were no significant differences in outcome between the two treatment groups for any of the three infections. Cure rates (clinical and microbiological for intra-abdominal infection, clinical for skin/skin-structure and pelvic infections) in microbiologically evaluable patients for ertapenem and piperacillin-tazobactam, respectively, were 85.6% (154/180 evaluable patients) and 82.5% (127/154) for polymicrobial intra-abdominal infection, 80.3% (53/66) and 78.7% (48/61) for polymicrobial skin/skin-structure infection, and 95.7% (88/92) and 92.6% (88/95) for polymicrobial pelvic infection. Respective cure rates for all evaluable patients in the original trials were: 83.6% and 80.4% for intra-abdominal, 83.9% and 85.3% for skin/skin-structure, and 93.9% and 91.5% for pelvic infections. These data show that in the three trials, ertapenem 1 g once a day was highly effective for the treatment of polymicrobial infections and as effective as piperacillin-tazobactam 3.375 g every 6 h.

Safety and tolerability of ertapenem

Ertapenem is a Group 1 carbapenem that was licensed in the USA in November 2001 and in Europe in April 2002. Its safety profile has been assessed in 240 healthy volunteers participating in 12 clinical pharmacology studies and in 2046 patients enrolled in five Phase IIa and eight Phase IIb/III clinical trials. The most common drug-related adverse events (AEs) reported in trials comparing ertapenem and piperacillin-tazobactam and in trials comparing ertapenem and ceftriaxone were: diarrhoea (ertapenem versus piperacillin-tazobactam 5.0% versus 7.0%; ertapenem versus ceftriaxone 5.6% versus 5.9%); infused vein complications (ertapenem versus piperacillin-tazobactam 4.5% versus 7.9%; ertapenem versus ceftriaxone 3.2% versus 4.6%); nausea (ertapenem versus piperacillin-tazobactam 2.5% versus 3.4%; ertapenem versus ceftriaxone 3.4% versus 3.3%); and elevations in alanine aminotransferase levels (ertapenem versus piperacillin-tazobactam 8.8% versus 7.3%; ertapenem versus ceftriaxone 8.3% versus 6.9%). Most ertapenem-related AEs were reported as mild-to-moderate in intensity. Ertapenem was not associated with prolongation of the QTc interval. Local reactions of moderate-to-severe intensity at the infusion site were infrequent and occurred with similar frequency in the ertapenem and comparator treatment groups. No overall differences in safety were observed between elderly (aged > or = 65 years and > or = 75 years) and younger patients. Ertapenem, 1 g once a day given by intravenous infusion or intramuscular injection, was generally well tolerated and had overall safety and tolerability profiles similar to those of piperacillin-tazobactam and ceftriaxone.

Treatment of complicated urinary tract infection in adults: combined analysis of two randomized, double-blind, multicentre trials comparing ertapenem and ceftriaxone followed by appropriate oral therapy

The efficacy and safety of parenteral ertapenem, a Group 1 carbapenem, 1 g once a day, for the treatment of complicated urinary tract infections (UTIs; i.e. acute pyelonephritis, UTI in men, or UTI associated with obstruction, foreign body or a urological abnormality interfering with normal voiding) in adults, were compared with those of parenteral ceftriaxone, 1 g once a day, in two similarly designed prospective, double-blind, randomized studies. In both studies, patients could be switched to an oral agent after > or = 3 days of parenteral study therapy. At entry, 850 patients were stratified according to whether they had acute pyelonephritis or other complicated UTI without acute pyelonephritis. Two hundred and fifty-six patients in the ertapenem group and 224 in the ceftriaxone group were microbiologically evaluable. Ninety-six per cent of these patients were switched to oral therapy, usually ciprofloxacin; the median (range) duration of parenteral and total therapy, respectively, was 4 (2-14) days and 13 (14-18) days for ertapenem and 4 (2-14) days and 13 (3-17) days for ceftriaxone. The most common pathogens were Escherichia coli and Klebsiella pneumoniae, which accounted for 64.7% and 9.8% of isolates, respectively. At the primary efficacy endpoint 5-9 days after treatment, 229 (89.5%) patients who received ertapenem and 204 (91.1%) patients who received ceftriaxone had a favourable microbiological response (95% confidence interval, -7.4 to 4.0), indicating that outcomes in the two treatment groups were equivalent. Success rates in both treatment groups were similar when compared by stratum and severity of infection. The frequency and severity of drug-related adverse events were generally similar in both treatment groups. In this combined analysis, ertapenem was highly effective therapy for the treatment of complicated UTIs in adults with moderate-to-severe disease.

Efficacy of ertapenem against methicillin-susceptible Staphylococcus aureus in complicated skin/skin structure infections: results of a double-blind clinical trial versus piperacillin-tazobactam

Staphylococcus aureus is the predominant pathogen in complicated skin/skin structure infections. In this analysis of a subgroup of data from a randomised, double-blind trial, the efficacy of ertapenem 1 g daily was compared with piperacillin-tazobactam 3.375 g Q6H for treatment of complicated skin/skin structure infections caused by methicillin-susceptible S. aureus (MSSA). Of the 529 treated patients in this trial, 185 (35.0%) had MSSA as a baseline pathogen. At the test of cure assessment 10-21 days post-therapy, 54 of 67 (80.6%) protocol evaluable patients in the ertapenem group and 55 of 68 (80.9%) in the piperacillin-tazobactam group were cured (odds ratio: 1.0 (95% confidence interval (CI): 0.4-2.4), P = 0.99). In both treatment groups, cure rates were higher in patients with monomicrobial than polymicrobial infections, but the difference was not significant. In this subgroup analysis of patients with MSSA complicated skin/skin structure infections, therapy with ertapenem 1 g daily was as effective as piperacillin-tazobactam 13.5 g divided in four daily doses.

Evaluation of outpatient treatment with ertapenem in a double blind controlled clinical trial of complicated skin/skin structure infections

OBJECTIVES

The patient characteristics and the efficacy and safety of ertapenem 1 g once daily vs. piperacillin-tazobactam 13.5 g divided Q6H were examined in patients who received outpatient parenteral antimicrobial therapy (OPAT) during a clinical trial of complicated skin/skin structure infections.

METHODS

The population analyzed included 363 patients treated at US sites in a large randomized double-blind study.

RESULTS

In this analysis, 146 (40%) patients at 19 (66%) sites were managed by OPAT. A lower proportion of treated patients who received OPAT had severe infection (12% vs. 20%, P=0.03). In evaluable patients managed by OPAT, 45 (83.3%) of 54 treated with ertapenem and 41 (82.0%) of 50 treated with piperacillin-tazobactam were cured at the test of cure assessment 10-21 days post-therapy (OR 1.2 (95% CI, 0.4-3.2), P=0.78). The safety profile of both drugs was generally similar; diarrhoea was the most common adverse event in both groups.

CONCLUSIONS

In this trial of complicated skin/skin structure infection, OPAT was commonly used by US investigators. Among patients who received OPAT, ertapenem 1 g daily was as effective as piperacillin-tazobactam 3.375 g Q6H.

Ertapenem Therapy for Community-Acquired Pneumonia in the Elderly

OBJECTIVES

To compare the efficacy and safety of ertapenem, 1 g once a day, with ceftriaxone, 1 g once a day, for treatment of the subgroup of patients aged 65 and older with community-acquired pneumonia (CAP) requiring parenteral therapy.

DESIGN

Combined data from patients aged 65 and older in two randomized, double-blind clinical trials.

SETTING

Eighty international centers.

PARTICIPANTS

Eight hundred fifty-seven treated patients, of whom 351 were aged 65 and older.

INTERVENTIONS

Intravenous or intramuscular ertapenem or ceftriaxone with the option to switch to oral amoxicillin-clavulanate after at least 3 days of parenteral therapy.

MEASUREMENTS

Clinical efficacy was assessed at completion of parenteral therapy and 7 to 14 days after all therapy had been completed (test of cure (TOC) assessment). Bacterial eradication was assessed at the TOC visit. Safety was assessed daily during study therapy and for 14 days thereafter.

RESULTS

One hundred forty-eight clinically evaluable patients aged 65 and older were treated with ertapenem and 125 with ceftriaxone. Pathogens were identified in 157 (57.5%) patients (the most common being Streptococcus pneumoniae), most of which were penicillin-susceptible. Clinical cure rates were 95.9% for patients in the ertapenem group and 92.7% for patients in the ceftriaxone group at completion of parenteral therapy and 93.9% and 90.4%, respectively, at the TOC assessment. Overall bacterial eradication rates were 92.8% (77 of 83) for patients treated with ertapenem and 93.2% (69 of 74) for those treated with ceftriaxone. The most common drug-related adverse experiences in both treatment groups were diarrhea and mild to moderate elevation of serum aminotransferase levels.

CONCLUSION

Ertapenem 1 g once a day was highly effective for treatment of elderly patients with CAP requiring parenteral therapy and was as effective as ceftriaxone. Ertapenem was generally well tolerated, with an overall safety profile similar to ceftriaxone.

Resistance in Enterobacteriaceae: results of a multicenter surveillance study, 1995-2000

OBJECTIVES

To assess changes over time in susceptibility of Enterobacteriaceae from patients in ICUs, compare susceptibility rates of isolates from patients in ICUs with those from inpatients outside ICUs, and explore phenotypic patterns of cross-resistance and co-resistance.

DESIGN

From 1995 to 2000, centers participating in the ICU Surveillance Study tested 100 to 200 consecutive nosocomial gram-negative bacilli by broth microdilution.

SETTING

Each year, 42 to 97 U.S. hospitals tested isolates.

RESULTS

In all years, imipenem was the most potent agent tested, followed by amikacin and ertapenem. Extended-spectrum beta-lactam and monobactam agents had good activity against Escherichia coli and Klebsiella species, but limited activity against Enterobacter species. Susceptibility to imipenem and amikacin did not fluctuate during the analysis period, whereas susceptibility to ceftazidime, ceftriaxone, and ciprofloxacin decreased 2% to 5%. The decline was most pronounced for susceptibility of Escherichia coli to ciprofloxacin: 98.7% of ICU isolates were susceptible in 1995 versus 93.2% in 2000. Susceptibility of ICU isolates was lower than that of non-ICU isolates, except for ciprofloxacin, for which the reverse was true. Cross-resistance was common among extended-spectrum cephalosporins and penicillins, but uncommon between imipenem and ertapenem. Only imipenem and ertapenem remained highly active against Enterobacteriaceae with a phenotype suggesting possible production of an extended-spectrum beta-lactamase and those with a phenotype suggesting possible Amp C hyperproduction.

CONCLUSIONS

Imipenem was the most active agent against nosocomial Enterobacteriaceae. Susceptibility to ciprofloxacin decreased from 1995 to 2000, particularly in Escherichia coli, and, in contrast to other agents, was lower among non-ICU isolates.

A rapid immunochromatographic assay for hepatitis B virus screening

Simple, rapid and accurate assays for hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) are helpful for clinical diagnosis and field epidemiological surveys. A commercially developed, rapid immunochromatographic test for simultaneous detection of HBsAg and HBeAg was evaluated using a total of 2463 selected samples (827 frozen sera, 1011 fresh sera, and 625 whole blood samples). Results of the rapid test were compared with standard enzyme immunoassay (EIA) methods for HBsAg and HBeAg detection. The accuracy of the rapid test was excellent and was similar for frozen sera, fresh sera and whole blood. The overall sensitivity and specificity for the detection of HBsAg were 95 and 100%, and the corresponding positive and negative predictive values were 100 and 99.7%, respectively. The sensitivity and specificity for the detection of HBeAg were slightly less than that for HBsAg, and were 80 and 98%, with positive and negative predictive values of 91 and 94%, respectively. Thus, compared with the EIA method, the rapid test was highly sensitive and accurate for the detection of HBsAg although somewhat less sensitive and specific for detection of HBeAg. Because of its speed, simplicity and flexibility, the rapid test is ideally suited for HBsAg and HBeAg screening in population-based epidemiological studies and in low risk populations, particularly in regions of the world where hepatitis B is endemic.

Expression of the uterine Mx protein in cyclic and pregnant cows, gilts, and mares

Pregnancy and interferon-tau (IFN tau) upregulate uterine Mx gene expression in ewes; however, the only known role for Mx is in the immune response to viral infection. We hypothesize that Mx functions as a conceptus-induced component of the anti-luteolytic mechanism and/or regulator of endometrial secretion or uterine remodeling during early pregnancy. This study was conducted to determine the effects of early pregnancy on uterine Mx expression in domestic farm species with varied mechanisms of pregnancy recognition. Endometrium from cows, gilts, and mares was collected during the first 20 d of the estrous cycle or pregnancy, and total messenger RNA (mRNA) and protein were analyzed for steady-state levels of Mx mRNA and protein. Northern blot analysis of Mx mRNA detected an approximately 2.5 Kb of mRNA in endometrium from each species. In pregnant cows, steady-state levels of Mx mRNA increased 10-fold (P < 0.05) above levels observed in cyclic cows by d 15 to 18. In cyclic gilts, slot blot analysis indicated that endometrial Mx mRNA levels did not change between d 5 and 18 of the cycle. However, in pregnant gilts, Mx levels tended (P = 0.06) to be elevated two-fold on d 16 only, and in situ hybridization indicated that this increase occurred in the stroma. In mares, Mx mRNA was low, but detectable, and did not change between ovulation (d 0) and d 20, regardless of reproductive status. Western blot analysis revealed multiple immunoreactive Mx protein bands in each species. One band was specific to pregnancy in cows. As in ewes, in situ hybridization analysis indicated that Mx mRNA was strongly expressed in the luminal epithelium, stroma, and myometrium by d 18 in cows. However, on d 14 in gilts, Mx was expressed primarily in the stroma, and on d 14 in mares, low levels of Mx expression were confined largely to the luminal epithelium. The uteruses of cows, gilts, and mares express Mx, and expression is upregulated during pregnancy in cows and gilts--animals whose conceptuses secrete interferons during early pregnancy, but that possess different mechanisms for pregnancy recognition.

Ertapenem versus piperacillin-tazobactam for treatment of mixed anaerobic complicated intra-abdominal, complicated skin and skin structure, and acute pelvic infections

BACKGROUND

Anaerobes are an important component of many serious, deep tissue infections, especially complicated intra-abdominal (IAI), complicated skin and skin structure (SSSI), and acute pelvic (PI) infections. This study compares the efficacy of ertapenem, 1 g once a day, in the treatment of adults with anaerobic IAI, SSSI, and PI to piperacillin-tazobactam, 3.375 g every 6 hours.

METHODS

Three randomized, double-blind trials comparing ertapenem to piperacillin-tazobactam for treatment of IAI, SSSI, and PI were conducted. This subgroup analysis included 623 patients, whose baseline culture grew one or more anaerobic pathogens, from these three studies.

RESULTS

Anaerobes most commonly isolated were Bacteroides fragilis group (IAI) and peptostreptococci (SSSI and PI). The median duration of ertapenem and piperacillin-tazobactam therapy, respectively, in these subgroups was 6 and 7 days for IAI, 7 and 8 days for SSSI, and 4 and 5 days for PI. Cure rates for all evaluable patients with anaerobic infection were 89.3% (242/271) for ertapenem and 85.9% (220/256) for piperacillin-tazobactam (95% CI for the difference, adjusting for infection, -2.6% to 9.3%), indicating that the two treatments were equivalent. Cure rates by infection, for ertapenem and piperacillin-tazobactam, respectively, were as follows: IAI, 86.4% (133/154) and 82.4% (117/142); SSSI, 84.4% (27/32) and 82.4% (28/34); PI, 96.5% (82/85) and 93.8% (75/80). The frequency and severity of drug-related adverse experiences were comparable in both treatment groups.

CONCLUSION

In this subgroup analysis, ertapenem was as effective as piperacillin-tazobactam for treatment of adults with moderate to severe anaerobic IAI, SSSI, and PI, was generally well tolerated, and had a similar safety profile.

Surgical infections with enterococcus: outcome in patients treated with ertapenem versus piperacillin-tazobactam

BACKGROUND

The pathogenicity of Enterococcus in polymicrobial surgical infections is controversial. The objective of this analysis was two-fold. The impact of Enterococcus on clinical outcome was assessed in adults with complicated intra-abdominal (IAI), complicated skin and skin structure (CSSSI), or acute pelvic (PI) infection treated with ertapenem or piperacillin-tazobactam, which is more active in vitro against enterococci than ertapenem. Baseline characteristics were identified that were associated with Enterococcus infection and with treatment failure.

METHODS

This analysis included 1,558 patients treated in three randomized, triple-blind studies. Of these patients, 223 had Enterococcus in initial cultures: 125 of 623 (20%) with IAI, 28 of 529 (5%) with CSSSI, and 70 of 406 (17%) with PI. Logistic regression models were fit to assess each objective.

RESULTS

The cure rates for the two treatment groups were similar in each of the three studies, regardless of the presence or absence of Enterococcus. Cure rates for both treatment groups combined were significantly lower in patients with Enterococcus than without Enterococcus for IAI (76% [69/91] versus 87% [264/305], OR 2.3 [95% CI, 1.2-4.1], P = 0.009) and CSSSI (58% [11/19] versus 84% [241/287], OR 3.8 [95% CI, 1.5-10.0], P = 0.010); but for PI, rates were similar (96% [50/52] versus 92% [188/205], OR 0.4 [95% CI, 0.1-1.9], P = 0.220). Characteristics predictive of the presence of Enterococcus were Pseudomonas aeruginosa as a baseline pathogen for IAI, older age, and the presence of a complicating underlying disease for CSSSI, and infection severity rated moderate rather than severe for PI. The strongest predictors of treatment failure were >2 days postoperative infection at study entry for patients with IAI and older age for patients with CSSSI.

CONCLUSION

Choice of antimicrobial therapy did not affect cure rates in patients with or without Enterococcus. The strongest predictors of failure were postoperative infection at study entry in patients with IAI and older age in patients with CSSSI.

Efficacy of ertapenem in the treatment of serious infections caused by Enterobacteriaceae: analysis of pooled clinical trial data

OBJECTIVE

The efficacy of ertapenem, 1 g once a day, for treatment of adults with serious infections caused by Enterobacteriaceae was compared with ceftriaxone 1 g once a day [complicated urinary tract infection (CUTI) and community-acquired pneumonia (CAP)] or piperacillin-tazobactam, 3.375 g every 6 h (complicated intra-abdominal, complicated skin/skin structure and acute pelvic infections).

PATIENTS AND METHODS

This combined analysis included the subgroup of all 1167 treated patients infected with Enterobacteriaceae from seven randomized double-blind studies.

RESULTS

Escherichia coli was the most common pathogen, accounting for 65.3% of all Enterobacteriaceae. Among evaluable patients with deep tissue (intra-abdominal, skin and pelvic) infections, the combined clinical cure rates were 84.8% (223 of 263) for ertapenem and 82.9% (194 of 234) for piperacillin-tazobactam [95% confidence interval (CI) for the difference, adjusting for infection, -4.9% to 8.9%]. Cure rates by infection for ertapenem and piperacillin-tazobactam, respectively, were: intra-abdominal, 85.1% (143 of 168) and 79.9% (119 of 149); pelvic, 86.8% (46 of 53) and 94% (47 of 50); skin/skin structure, 81% (34 of 42) and 80% (28 of 35). Among patients with CUTI, microbiological cure rates were 90.5% (220 of 243) for ertapenem and 92% (196 of 213) for ceftriaxone (95% CI for the difference, -7.1% to 4.1%). In patients with CAP, clinical cure rates were 95% (19 of 20) for ertapenem and 88.9% (16 of 18) for ceftriaxone.

CONCLUSION

Ertapenem therapy was as effective as either piperacillin-tazobactam or ceftriaxone for serious infections caused by Enterobacteriaceae.

Phenotypic antimicrobial resistance patterns in Pseudomonas aeruginosa and Acinetobacter: results of a Multicenter Intensive Care Unit Surveillance Study, 1995-2000

Susceptibility data from the Intensive Care Unit (ICU) Surveillance Study for 10,361 isolates of Pseudomonas aeruginosa and 2,573 isolates of Acinetobacter tested at centers in the United States during 1995 to 2000 were analyzed. In all years, amikacin was the most active antimicrobial agent against P. aeruginosa, and imipenem was the most active agent against Acinetobacter. Resistance of both organisms to common therapeutic agents tested throughout the analysis period increased from 1995 to 2000, although the increase was not consistent for all drugs from year to year. The increases were higher among Acinetobacter, and for both organisms, the increase in resistance was greatest for ciprofloxacin. Among all P. aeruginosa tested in 1999 and 2000, resistance to ciprofloxacin was 9-11% higher for isolates from patients on general hospital wards than those from ICUs. Of the 3424 ICU isolates of P. aeruginosa tested in 1999 and 2000, 77 (2.2%) were multidrug-resistant (i.e., resistant to piperacillin, ceftazidime, imipenem, and gentamicin). Twenty (3.9%) isolates of Acinetobacter in 1999 and seven (1.9%) in 2000 were resistant to imipenem, ceftazidime, piperacillin-tazobactam, ciprofloxacin, and amikacin. Although resistance in both P. aeruginosa and Acinetobacter increased, multidrug-resistant (to > or =4 agents) strains were uncommon.

Multisite reproducibility of results obtained by two broth dilution methods for susceptibility testing of Mycobacterium avium complex

A multicenter study was conducted to assess the interlaboratory reproducibility of susceptibility testing of Mycobacterium avium complex (MAC) by broth microdilution using two different media (cation-adjusted Mueller-Hinton broth with 5% oleic acid-albumin-dextrose-catalase and 7H9 broth with casein) and by macrodilution using the BACTEC 460TB and 12B media at pH 6.8 and 7.3 to 7.4. Ten well-characterized strains of MAC (four macrolide susceptible, six macrolide resistant) were tested against clarithromycin and azithromycin (the latter only by BACTEC 460TB, pH 6.8). At each site, strains were tested against clarithromycin three times on each of three separate days (nine testing events per isolate) by using a common lot of microdilution trays and BACTEC 12B medium, pH 6.8; strains were tested once on three separate days against clarithromycin in 12B medium at pH 7.3 to 7.4 and against azithromycin. Agreement among MICs (i.e., mode +/- 1 twofold dilution) was 100% for all strains and both drugs when BACTEC 460TB was used, regardless of the pH of the medium, but varied when microdilution with either medium was used, particularly with susceptible strains. Agreement based on interpretive category, with NCCLS-recommended breakpoints, was 100% for all strains with the BACTEC 460TB method (both drugs and both pH values) and with microdilution using 7H9 broth. With microdilution and Mueller-Hinton broth, agreement by interpretive category was 100% for eight isolates and >90% for two; errors occurred only in laboratories where personnel had minimal experience with this technique. MAC susceptibility testing may be performed by broth macrodilution or microdilution at either pH, with NCCLS-recommended interpretive breakpoints. However, because visual interpretation of broth microdilution end points is subjective, it is more prone to reader error; therefore, this method requires greater expertise than the BACTEC 460TB. Both techniques require appropriate validation and continued documentation of proficiency.

Ertapenem once a day versus piperacillin-tazobactam every 6 hours for treatment of acute pelvic infections: a prospective, multicenter, randomized, double-blind study

OBJECTIVE

To compare ertapenem therapy with piperacillin-tazobactam therapy for the management of acute pelvic infections.

METHODS

In a multicenter, double-blind study, 412 women with acute pelvic infection were assigned to one of two strata, namely obstetric/postpartum infection or gynecologic/postoperative infection, and were then randomized to ertapenem, 1 g once a day, or piperacillin-tazobactam, 3.375 g every 6 hours, both administered intravenously.

RESULTS

In total, 163 patients in the ertapenem group and 153 patients in the piperacillin-tazobactam group were clinically evaluable. The median duration of therapy was 4.0 days in both treatment groups. The most common single pathogen was Escherichia coli. At the primary efficacy endpoint 2-4 weeks post therapy, 93.9% of patients who received ertapenem and 91.5% of those who received piperacillin-tazobactam were cured (95% confidence interval for the difference, adjusting for strata, -4% to 8.8%), indicating that cure rates for both treatment groups were equivalent. Cure rates for both treatment groups were also similar when compared by stratum and severity of infection. The frequency and severity of drug-related adverse events were generally similar in both groups.

CONCLUSIONS

In this study, ertapenem was as effective as piperacillin-tazobactam for the treatment of acute pelvic infection, was generally well tolerated, and had an overall safety profile similar to that of piperacillin-tazobactam.

Comparative in vitro activity of ertapenem against bacterial pathogens isolated from patients with lower respiratory tract infections

This study compared the in vitro activity of ertapenem, ceftriaxone, cefepime, ciprofloxacin and amoxicillin-clavulanate against 381 aerobic and facultative bacterial pathogens isolated from 320 patients with acute bacterial exacerbation of chronic bronchitis or community-acquired pneumonia. Streptococcus pneumoniae and Haemophilus influenzae accounted for 54.6% of the isolates. The ertapenem MIC was < or =2 mg/L for 98.4% of isolates and > or =8 mg/L for 1.0% (all methicillin-resistant Staphylococcus aureus). Ertapenem had the most potent activity against Enterobacteriaceae, Moraxella catarrhalis, and methicillin-susceptible S. aureus, and its activity against H. influenzae and H. parainfluenzae, all strains of which were susceptible, was not altered by beta-lactamase production. Only one S. pneumoniae strain, a penicillin-resistant isolate, was resistant to ertapenem. Ertapenem was highly active in vitro against pyogenic bacteria recovered from patients with community-acquired lower respiratory tract infections.