Update: Novel Influenza A (H1N1) Virus Infections — Worldwide, May 6, 2009

MMWR Weekly May 8, 2009  V.58  N.17  p.453-458

Full Text

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5817a1.htm?s_cid=mm5817a1_e

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http://www.cdc.gov/mmwr/PDF/wk/mm5817.pdf

 

Increased Amoxicillin–Clavulanic Acid Resistance in Escherichia coli Blood Isolates, Spain

Emerging Infectious Diseases Journal August 2008  V.14  N.8

Jesús Oteo,* José Campos,*†  Edurne Lázaro,‡ Óscar Cuevas,* Silvia García-Cobos,* María Pérez-Vázquez,* F.J. de Abajo,‡ and Spanish Members of EARSS1

*Instituto de Salud Carlos III, Madrid, Spain; †Consejo Superior de Investigaciones Científicas, Madrid; and ‡Agencia Española del Medicamento y Productus Sanitarios, Madrid

Abstract

To determine the evolution and trends of amoxicillin–clavulanic acid resistance among Escherichia coli isolates in Spain, we tested 9,090 blood isolates from 42 Spanish hospitals and compared resistance with trends in outpatient consumption. These isolates were collected by Spanish hospitals that participated in the European Antimicrobial Resistance Surveillance System network from April 2003 through December 2006.

Full Text

http://www.cdc.gov/eid/content/14/8/1259.htm?s_cid=eid1259_e

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http://www.cdc.gov/eid/content/14/8/pdfs/1259.pdf

Infection with Panton-Valentine Leukocidin–Positive Methicillin-Resistant Staphylococcus aureus t034

Emerging Infectious Diseases Journal August 2008  V.14  N.8

Christina Welinder-Olsson,*  Kerstin Florén-Johansson,* Leif Larsson,* Sven Öberg,† Lisbeth Karlsson,‡ and Christina Åhrén*

*Sahlgrenska University Hospital, Göteborg, Sweden; †Uddevalla Hospital, Uddevalla, Sweden; and ‡Borås Hospital, Borås, Sweden

Abstract

Panton-Valentine leukocidin (PVL)–positive methicillin-resistant Staphylococcus aureus (MRSA), sequence type 398 is believed to be of animal origin. We report 2 cases of infection due to PVL–positive MRSA, spa type t034, in patients in Sweden who had had no animal contact.

Full Text

http://www.cdc.gov/eid/content/14/8/1271.htm?s_cid=eid1271_e

 

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http://www.cdc.gov/eid/content/14/8/pdfs/1271.pdf

Enterotoxigenic Escherichia coli in Developing Countries: Epidemiology, Microbiology, Clinical Features, Treatment, and Prevention

Clinical Microbiology Reviews  1 July 2005  V.18  N.3  p.465-483

Firdausi Qadri,1 Ann-Mari Svennerholm,2 A. S. G. Faruque,1 and R. Bradley Sack3*

International Centre for Diarrhoeal Disease Research, Bangladesh, and Centre for Health and Population Research, Mohakhali, Dhaka 1212, Bangladesh,1 Department of Medical Microbiology and Immunology, Göteborg University, 40530 Göteborg, Sweden ,2 Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland3

ETEC is an underrecognized but extremely important cause of diarrhea in the developing world where there is inadequate clean water and poor sanitation. It is the most frequent bacterial cause of diarrhea in children and adults living in these areas and also the most common cause of traveler’s diarrhea. ETEC diarrhea is most frequently seen in children, suggesting that a protective immune response occurs with age. The pathogenesis of ETEC-induced diarrhea is similar to that of cholera and includes the production of enterotoxins and colonization factors. The clinical symptoms of ETEC infection can range from mild diarrhea to a severe cholera-like syndrome. The effective treatment of ETEC diarrhea by rehydration is similar to treatment for cholera, but antibiotics are not used routinely for treatment except in traveler’s diarrhea. The frequency and characterization of ETEC on a worldwide scale are inadequate because of the difficulty in recognizing the organisms; no simple diagnostic tests are presently available. Protection strategies, as for other enteric infections, include improvements in hygiene and development of effective vaccines. Increases in antimicrobial resistance will dictate the drugs used for the treatment of traveler’s diarrhea. Efforts need to be made to improve our understanding of the worldwide importance of ETEC.

abstract

http://cmr.asm.org/cgi/content/abstract/18/3/465?etoc

 

PDF

http://cmr.asm.org/cgi/reprint/18/3/465

Plasmodium ovale: Parasite and Disease

Clinical Microbiology Reviews  1 July 2005  V.18  N.3  p.570-581

William E. Collins1* and Geoffrey M. Jeffery2

Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Parasitic Diseases, Malaria Branch, Chamblee, Georgia 30341,1 U.S. Public Health Service, Atlanta, Georgia2

Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected Anopheles mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of 101°F and 4.5 fever episodes of 104°F. Mean maximum parasite levels were 6,944/µl for sporozoite-induced infections and 7,310/µl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and Saimiri monkeys following injection of sporozoites. Many different Anopheles species have been shown to be susceptible to infection with P. ovale, including A. gambiae, A. atroparvus, A. dirus, A. freeborni, A. albimanus, A. quadrimaculatus, A. stephensi, A. maculatus, A. subpictus, and A. farauti. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with P. ovale using a monoclonal antibody directed against the circumsporozoite protein. Plasmodium ovale is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of P. ovale is based primarily on the characteristics of the blood stages and its differentiation from P. vivax. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for P. ovale. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that P. ovale is closely related phylogenetically to any other of the primate malaria parasites that have been examined.

abstract

http://cmr.asm.org/cgi/content/abstract/18/3/570?etoc

 

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http://cmr.asm.org/cgi/reprint/18/3/570

Diagnostic Accuracy of a Rapid Real-Time Polymerase Chain Reaction Assay for Universal Intrapartum Group B Streptococcus Screening

Clinical Infectious Diseases  Aug.1, 2009  V.49  N.3  p.417–423

Najoua El Helali,1 Jean-Claude Nguyen,1 Aïcha Ly,1 Yves Giovangrandi,2 and Ludovic Trinquart3,4,5

Services de 1Microbiologie and 2Gynécologie-Obstétrique, Groupe Hospitalier Paris Saint-Joseph, 3Université Paris Descartes, 4Unité de Recherche Clinique, Hôpital Européen Georges Pompidou, Assistance Publique Hôpitaux de Paris, and 5Centre d’Investigation Épidémiologique 4, INSERM, Paris, France

Background. Intrapartum antibiotic prophylaxis is currently given to mothers who test positive for group B streptococcus (GBS) by antenatal culture-based screening, with a risk-based approach for cases with an unknown GBS status. A rapid real-time polymerase chain reaction (PCR) assay for the detection of GBS became available recently, making intrapartum screening possible. We aimed to assess its diagnostic accuracy and to compare it with antenatal screening.

Methods. We conducted a prospective study in a French hospital. All pregnant women giving birth at the maternity ward were considered for inclusion, except those with planned cesarean delivery, with delivery at <35 weeks gestation, and who received antibiotic therapy before admission. We performed GBS culture (the reference standard) and a molecular GBS test (Xpert GBS; Cepheid) on intrapartum specimens. Decisions about intrapartum antibiotic prophylaxis were based on the current GBS screening by culture at 35–37 weeks gestation.

Results. We prospectively enrolled 968 pregnant women from April 2007 through March 2008. The overall molecular GBS test yield was 89.2%. Among the 863 women with available results, the molecular GBS test had a sensitivity of 98.5%, specificity of 99.6%, positive predictive value of 97.8%, and negative predictive value of 99.7%. The positive predictive value of antenatal culture for identifying colonization status at delivery was low (58.3%), whereas the negative predictive value was imperfect (92.1%).

Conclusions. This real-time PCR assay is a highly accurate test to identify intrapartum GBS carriers at point of care. This new tool could enhance the exact identification of candidates for intrapartum antibiotic prophylaxis, including women with preterm rupture of membranes or preterm labor.

abstract

http://www.journals.uchicago.edu/doi/abs/10.1086/600303

Systematic Review: T-Cell–based Assays for the Diagnosis of Latent Tuberculosis Infection: An Update

Annals of Internal Medicine  5 August 2008  V.149  N.3  p.177-184

REVIEW

Madhukar Pai, MD, PhD; Alice Zwerling, MSc; and Dick Menzies, MD, MSc

From McGill University and Montreal Chest Institute, Montreal, Quebec, Canada.

 

Background: Interferon-–release assays (IGRAs) are alternatives to the tuberculin skin test (TST). A recent meta-analysis showed that IGRAs have high specificity, even among populations that have received bacille Calmette–Guérin (BCG) vaccination. Sensitivity was suboptimal for TST and IGRAs.

Purpose: To incorporate newly reported evidence from 20 studies into an updated meta-analysis on the sensitivity and specificity of IGRAs.

Data Sources: PubMed was searched through 31 March 2008, and citations of all original articles, guidelines, and reviews for studies published in English were reviewed.

Study Selection: Studies that evaluated QuantiFERON-TB Gold, QuantiFERON-TB Gold In-Tube (both from Cellestis, Victoria, Australia), and T-SPOT.TB (Oxford Immunotec, Oxford, United Kingdom) or its precommercial ELISpot version, when data on the commercial version were lacking. For assessing sensitivity, the study sample had to have microbiologically confirmed active tuberculosis. For assessing specificity, the sample had to comprise healthy, low-risk individuals without known exposure to tuberculosis. Studies with fewer than 10 participants and those that included only immunocompromised participants were excluded.

Data Extraction: One reviewer abstracted data on participant characteristics, test characteristics, and test performance from 38 studies; these data were double-checked by a second reviewer. The original investigators were contacted for additional information when necessary.

Data Synthesis: A fixed-effects meta-analysis with correction for overdispersion was done to pool data within prespecified subgroups. The pooled sensitivity was 78% (95% CI, 73% to 82%) for QuantiFERON-TB Gold, 70% (CI, 63% to 78%) for QuantiFERON-TB Gold In-Tube, and 90% (CI, 86% to 93%) for T-SPOT.TB. The pooled specificity for both QuantiFERON tests was 99% among non–BCG-vaccinated participants (CI, 98% to 100%) and 96% (CI, 94% to 98%) among BCG-vaccinated participants. The pooled specificity of T-SPOT.TB (including its precommercial ELISpot version) was 93% (CI, 86% to 100%). Tuberculin skin test results were heterogeneous, but specificity in non–BCG-vaccinated participants was consistently high (97% [CI, 95% to 99%]).

Limitations: Most studies were small and had limitations, including no gold standard for diagnosing latent tuberculosis and variable TST methods and cutoff values. Data on the specificity of the commercial T-SPOT.TB assay were limited.

Conclusion: The IGRAs, especially QuantiFERON-TB Gold and QuantiFERON-TB Gold In-Tube, have excellent specificity that is unaffected by BCG vaccination. Tuberculin skin test specificity is high in non–BCG-vaccinated populations but low and variable in BCG-vaccinated populations. Sensitivity of IGRAs and TST is not consistent across tests and populations, but T-SPOT.TB appears to be more sensitive than both QuantiFERON tests and TST.

abstract

http://www.annals.org/cgi/content/abstract/149/3/177?etoc

PDF

http://www.annals.org/cgi/reprint/149/3/177.pdf

A Prediction Rule for Estimating the Risk of Bacteremia in Patients with Community-Acquired Pneumonia

Clinical Infectious Diseases  Aug.1, 2009  V.49  N.3  p.409–416

Miquel Falguera,1 Javier Trujillano,2 Sílvia Caro,1 Rosario Menéndez,5 Jordi Carratalà,6 Agustín Ruiz-González,1 Manuel Vilà,3 Mercè García,4 José Manuel Porcel,1 Antoni Torres,7 and the NAC-CALIDAD (Proyecto Integrado de Investigación de la Sociedad Española de Patología del Aparato Respiratorio sobre Infecciones Respiratorias de Vías Bajas) Study Groupa

Services of 1Internal Medicine, 2Critical Care, 3Pneumology, and 4Microbiology, Hospital Universitari Arnau de Vilanova, Universitat de Lleida, Institut de Recerca Biomèdia de Lleida, Ciber de Enfermedades Respiratorias (Ciberes 06/06/0028), Lleida, 5Pneumology Service, Hospital Universitari La Fe, Ciber de Enfermedades Respiratorias (Ciberes 06/06/0028), Valencia, and 6Infectious Diseases Service, Hospital Universitari de Bellvitge, Universitat de Barcelona, Institut d’Investigació Biomèdica de Bellvitge, and 7Pneumology Department, Clinic Institute of Thorax, Hospital Clinic of Barcelona, Universitat de Barcelona, Institut d’Investigacions Biomèdiques August Pi I Sunyer, Ciber de Enfermedades Respiratorias (Ciberes 06/06/0028), Barcelona, Spain

Background. We endeavored to construct a simple score based entirely on epidemiological and clinical variables that would stratify patients who require hospital admission because of community-acquired pneumonia into groups with a low or high risk of developing bacteremia.

Methods. Derivation and internal validation cohorts were obtained by retrospective analysis of a database that included 3116 consecutive patients with community-acquired pneumonia from 2 university hospitals. Potential predictive factors were determined by means of a multivariate logistic regression equation applied to a cohort consisting of 60% of the patients. Points were assigned to significant parameters to generate the score. It was then internally validated with the remaining 40% of patients and was externally validated using an independent multicenter cohort of 1369 patients.

Results. The overall rates of bacteremia were 12%–16% in the cohorts. The clinical probability estimate of developing bacteremia was based on 6 variables: liver disease, pleuritic pain, tachycardia, tachypnea, systolic hypotension, and absence of prior antibiotic treatment. For the score, 1 point was assigned to each predictive factor. In the derivation cohort, a cutoff score of 2 best identified the risk of bacteremia. In the validation cohorts, rates of bacteremia were <8% for patients with a score 1 (43%–49% of patients), whereas blood culture results were positive in 14%–63% of cases for patients with a score 2.

Conclusions. This clinical score, based on readily available and objective variables, provides a useful tool to predict bacteremia. The score has been internally and externally validated and may be useful to guide diagnostic decisions for community-acquired pneumonia.

abstract

http://www.journals.uchicago.edu/doi/abs/10.1086/600291

Salvage Treatment for Persistent Methicillin-Resistant Staphylococcus aureus Bacteremia: Efficacy of Linezolid With or Without Carbapenem

Clinical Infectious Diseases  Aug.1, 2009  V.49  N.3  p.395–401

Hee-Chang Jang,1 Sung-Han Kim,1,a Kye Hyoung Kim,1 Choong Jong Kim,1 Shinwon Lee,1 Kyoung-Ho Song,1 Jae Hyun Jeon,1 Wan Beom Park,1 Hong Bin Kim,1 Sang-Won Park,1 Nam Joong Kim,1 Eui-Chong Kim,2 Myoung-don Oh,1 and Kang Won Choe1

Departments of 1Internal Medicine and 2Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea

Background. Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is associated with high mortality rates, but no treatment strategy has yet been established. We performed this study to evaluate the efficacy of linezolid with or without carbapenem in salvage treatment for persistent MRSA bacteremia.

Methods. All adult patients with persistent MRSA bacteremia for 7 days from January 2006 through March 2008 who were treated at Seoul National University Hospital were studied. The results of linezolid salvage therapy with or without carbapenem were compared with those of salvage therapy with vancomycin plus aminoglycosides or rifampicin.

Results. Thirty-five patients with persistent MRSA bacteremia were studied. The early microbiological response (ie, negative results for follow-up blood culture within 72 hours) was significantly higher in the linezolid-based salvage therapy group than the comparison group (75% vs 17%;  ). Adding aminoglycosides or rifampicin to vancomycin was not successful in treating any of the patients, whereas linezolid-based therapy gave an 88% salvage success rate ( ). The S. aureus–related mortality rate was lower for patients treated with a linezolid salvage regimen than for patients continually treated with a vancomycin-based regimen (13% vs 53%;  ).

Conclusions. Linezolid-based salvage therapy effectively eradicated S. aureus from the blood for patients with persistent MRSA bacteremia. The salvage success rate was higher for linezolid therapy than for vancomycin-based combination therapy.

abstract

http://www.journals.uchicago.edu/doi/abs/10.1086/600295

Nosocomial Transmission of Invasive Group A Streptococcus from Patient to Health Care Worker

Clinical Infectious Diseases  Aug.1, 2009  V.49  N.3  p.354–357

Mark D. Lacy and Kim Horn

Infectious Disease Service, Flagstaff Medical Center, Flagstaff, Arizona

Background. Nosocomial transmission of group A streptococcus (GAS) has been well described. Instances resulting in fulminant disease among health care workers have not been described. Contact and droplet precautions have been advised to minimize the risk of nosocomial transmission. We aimed to determine whether a case of invasive GAS pneumonia and streptococcal toxic shock syndrome in a respiratory therapist was acquired as a result of caring for a patient with GAS necrotizing fasciitis. Contacts of these patients were screened to determine if they were the reservoir of the GAS. Genetic testing to confirm clonal transmission was conducted.

Methods. Contacts of the patients with GAS infection were screened using questionnaires and testing of pharyngeal specimens. Specimens from patients and carriers of GAS who were identified during screening were subjected to pulsed-field gel electrophoresis and emm gene typing.

Results. We identified 705 contacts of the 2 patients; all contacts had oropharyngeal specimens collected for culture. Only the index patient and the respiratory therapist yielded identical pulse-field gel electrophoresis GAS isolates, with clonality indicated by emm typing.

Conclusions. Nosocomial transmission of GAS from a patient to a health care worker who developed streptococcal toxic shock syndrome may have occurred after the index patient had received 48 h of antibiotic therapy and despite placement in contact isolation. Isolation guidelines for patients with severe GAS infection may need to be reviewed.

abstract

http://www.journals.uchicago.edu/doi/abs/10.1086/599832

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