Etymologia: Verona Integron - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

Etymologia: Verona Integron - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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Volume 19, Number 7—July 2013

Etymologia

Etymologia: Verona Integron

Article Contents

• Etymologia
• References
• Suggested Citation

Suggested citation for this article

Verona Integron
From the Latin integrare (to make whole), integrons are systems for capturing and spreading antibiotic resistance genes among gram-negative bacteria. Integrons were first described by Stokes and Hall in 1989, although they clearly contributed to the first outbreaks of multidrug resistance in the 1950s. The Verona integron was first described in carbapenem-resistant Pseudomonas aeruginosa isolated from a patient hospitalized at Verona University Hospital, Verona, Italy. Integrons are ancient structures that have been present in bacteria for millions of years, indicating that bacteria had the means of acquiring and disseminating antibiotic resistance long before humans developed antibiotics.

References

1. Lauretti L, Riccio ML, Mazzariol A, Cornaglia G, Amicosante G, Fontana R, Cloning and characterization of bla_VIM, a new integron-borne metallo-β-lactamase gene from a Pseudomonas aeruginosa clinical isolate. Antimicrob Agents Chemother. 1999;43:1584–90 .PubMed
2. Mazel D. Integrons: agents of bacterial evolution. Nat Rev Microbiol. 2006;4:608–20 . DOIPubMed
3. Stokes HW, Hall RM. A novel family of potentially mobile DNA elements encoding site-specific gene-integration functions: integrons. Mol Microbiol. 1989;3:1669–83 . DOIPubMed

Suggested citation for this article: Etymologia: Verona integron. Emerg Infect Dis [serial on the Internet]. 2013 Jul [date cited]. http://dx.doi.org/10.3201/eid1907.ET1907

DOI: 10.3201/eid1907.ET1907

Multidrug-Resistant Atypical Variants of Shigella flexneri in China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Multidrug-Resistant Atypical Variants of Shigella flexneri in China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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Volume 19, Number 7—July 2013

Dispatch

Multidrug-Resistant Atypical Variants of Shigella flexneri in China

Article Contents

• The Study
• Conclusions
• Acknowledgment
• References
• Table 1
• Table 2
• Technical Appendix [415 KB - 3 pages]
• Suggested Citation

Shaofu Qiu¹, Yong Wang¹, Xuebin Xu¹, Peng Li¹, Rongzhang Hao¹, Chaojie Yang¹, Nan Liu¹, Zhenjun Li¹, Zhongqiang Wang¹, Jian Wang¹, Zhihao Wu¹, Wenli Su¹, Guang Yang¹, Huiming Jin¹, Ligui Wang¹, Yansong Sun, Zhengan Yuan, Liuyu Huang, and Hongbin Song

Author affiliations: Academy of Military Medical Sciences, Beijing, China (S. Qiu, Y. Wang, P. Li, R. Hao, C. Yang, N. Liu, Z. Wang, J. Wang, Z. Wu, W. Su, G. Yang, L. Wang, Y. Sun, L. Huang, H. Song); Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China (X. Xu, H. Jin, Z. Yuan); Chinese Center for Disease Control and Prevention, Beijing (Z. Li)

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Abstract

We identified 3 atypical Shigella flexneri varieties in China, including 92 strains with multidrug resistance, distinct pulse types, and a novel sequence type. Atypical varieties were prevalent mainly in developed regions, and 1 variant has become the dominant Shigella spp. serotype in China. Improved surveillance will help guide the prevention and control of shigellosis.

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), which is of particular concern in developing countries. Shigella spp. are leading bacterial causes of diarrhea, responsible for >80 million cases of bloody diarrhea and 700,000 deaths each year (2), and S. flexneri serotype 2a has been recognized as the most prevalent serotype in China for many years (3). To better understand the etiology of bacterial diarrhea in China and to determine if S. flexneri serotype 2a is still the most prevalent serotype in China, we conducted a study during May 2008–December 2010.

The Study

A total of 10,021 fecal samples were obtained from patients with diarrhea or dysentery at hospitals in 8 provinces within the eastern, southern, western, northern, and central regions of China: Liaoning, Shandong, Jiangsu, Guangdong, Gansu, Sichuan, Xinjiang, and Hebei Provinces. Samples were screened for the presence of Shigella spp. by using API 20E strips (bioMérieux, Marcy l’Etoile, France). Serotyping was performed by using 1) an antisera kit specific for all type- and group-factor antigens (Denka Seiken, Tokyo, Japan) and 2) a panel of monoclonal antibodies against S. flexneri (MASF; Reagensia AB, Stockholm, Sweden). Antimicrobial susceptibility testing was performed by the disk diffusion method as described (4). Genetic relationships were estimated by using multilocus sequence typing, as described (5), and pulsed-field gel electrophoresis (PFGE) (6).

Clinical Findings for Early Human Cases of Influenza A(H7N9) Virus Infection, Shanghai, China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Clinical Findings for Early Human Cases of Influenza A(H7N9) Virus Infection, Shanghai, China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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Volume 19, Number 7—July 2013

Dispatch

Clinical Findings for Early Human Cases of Influenza A(H7N9) Virus Infection, Shanghai, China

Article Contents

• Case Reports
• Discussion
• Acknowledgments
• References
• Figure 1
• Figure 2
• Table 1
• Table 2
• Technical Appendix [310 KB - 3 pages]
• Suggested Citation

Shuihua Lu¹ , Yufang Zheng¹, Tao Li¹, Yunwen Hu¹, Xinian Liu, Xiuhong Xi, Qingguo Chen, Qingle Wang, Ye Cao, Yanbing Wang, Lijun Zhou, Douglas Lowrie, and Jing Bao

Author affiliations: Shanghai Public Health Clinical Center, Shanghai, China (S. Lu, Y. Zheng, T. Li, Y. Hu, X. Liu, X. Xi, Q. Chen, Q. Wang, Y. Cao, Y. Wang, L. Zhou, D. Lowrie); Henry M Jackson Foundation–Division of AIDS, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA (J. Bao)

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Abstract

A novel strain of influenza A(H7N9) virus has emerged in China and is causing mild to severe clinical symptoms in infected humans. Some case-patients have died. To further knowledge of this virus, we report the characteristics and clinical histories of 4 early case-patients.

Avian influenza A(H7N9) virus normally circulates among birds; however, human infections with this virus were confirmed in China on March 31, 2013 (1,2). To help identify the best treatment strategies for influenza A(H7N9) virus infection, we summarized the clinical characteristics and outcomes for the first 4 patients who were transferred to Shanghai Public Health Clinical Center (SHPHCC) for treatment of influenza A(H7N9) virus infection. For each case, infection was confirmed by the Shanghai Municipal Centers for Disease Control and Prevention.

Case Reports

Clinical features of the 4 case-patients are listed in Table 1. All case-patients were 58- to 73-year-old married men, farmers or retirees, and long-term residents of Shanghai (Fengxian, Baoshan, Songjiang, and Pudong districts, respectively). Case-patient 1 had a history of coronary heart disease and hepatic schistosomiasis; case-patient 2 had no history of chronic disease; case-patient 3 had a history of hypertension and gout; and case-patient 4 had a history of hypertension and repetitive cough for > 10 years during spring and autumn.

Case-patient 1 raised chickens at home. Case-patients 2–4 had no clear history of close contact with poultry; however, each had visited various farmers’ markets that sold live poultry. None of the patients raised pigeons or live in or near a heavily pigeon-infested area.
Before being transferred to SHPHCC on April 6, 2013 (patients 1 and 2) and April 7, 2013 (patients 3 and 4), the 4 patients had been treated in local hospitals; infection with influenza A(H7N9) virus had been confirmed by real-time reverse transcription PCR of nasopharyngeal swab samples before transfer. The case-patients had cough and fever and had been expectorating sputum for ≈6–7 days before admittance to SHPHCC. In addition, all had experienced cold-like symptoms and fatigue before influenza-like symptoms developed. Case-patient 4 had cough and fever for 18 and 10 days, respectively, before being transferred to SHPHCC; his case was the most serious of the 4, and the disease progressed rapidly after he was transferred to SHPHCC.

Undetected Multidrug-Resistant Tuberculosis Amplified by First-line Therapy in Mixed Infection - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Undetected Multidrug-Resistant Tuberculosis Amplified by First-line Therapy in Mixed Infection - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Suggested citation for this article

Volume 19, Number 7—July 2013

Dispatch

Undetected Multidrug-Resistant Tuberculosis Amplified by First-line Therapy in Mixed Infection

Article Contents

• The Study
• Conclusions
• Acknowledgments
• References
• Figure 1
• Figure 2
• Table
• Suggested Citation

Suzanne M. Hingley-Wilson¹ , Rosalyn Casey¹, David Connell, Samuel Bremang, Jason T. Evans, Peter M. Hawkey, Grace E. Smith, Annette Jepson, Stuart Philip, Onn Min Kon, and Ajit Lalvani

Author affiliations: Imperial College London, London, UK (S.M. Hingley-Wilson, R. Casey, D. Connell, S. Bremang, A. Lalvani); Heart of England National Health Service Foundation Trust, Birmingham, UK (J.T. Evans, P.M. Hawkey, G.E. Smith); School of Infection and Immunity, University of Birmingham, Birmingham (P.M. Hawkey); Imperial College National Health Service HealthcareTrust, London (A. Jepson, S. Philip, O.M. Kon); 1Current affiliation: University of Surrey, Guildford, UK.

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Abstract

Infections with >1 Mycobacterium tuberculosis strain(s) are underrecognized. We show, in vitro and in vivo, how first-line treatment conferred a competitive growth advantage to amplify a multidrug-resistant M. tuberculosis strain in a patient with mixed infection. Diagnostic techniques that identify mixed tubercle bacilli populations are needed to curb the spread of multidrug resistance.

As the number of multidrug-resistant tuberculosis (TB) cases continues to rise, so does the amplification of multidrug-resistant Mycobacterium tuberculosis strains during treatment (1,2). This amplification is generally assumed to result from in vivo evolution of drug resistance caused by poor therapy compliance or, in high-incidence settings, from exogenous reinfection with a multidrug-resistant strain. We report a case in which emergence of multidrug resistance did not result from in vivo acquisition of drug resistance by a drug-sensitive strain or from exogenous reinfection with an already resistant strain. By integrating epidemiologic, microbiological, and molecular strain typing data with in vitro competitive growth experiments, we provide evidence for an initial mixed infection with a drug-sensitive strain and an undetected drug-resistant strain that outgrew the sensitive strain under the selection pressure of first-line chemotherapy.
M. tuberculosis strains in sputum from TB-infected patients or in samples from the disease site are generally identified by strain typing a single broth culture or colony grown on solid medium. However, this method does not enable identification of mixed infections, and any treatment regimen would be determined on the basis of the drug sensitivity of the strain with the fastest growth rate in the in vitro culture. Use of suboptimal drug combinations could lead to selection of a slower growing, drug-resistant strain already present in the host and thus to treatment failure.
Studies of artificially mixed M. tuberculosis strains before and after culture showed that culturing can reduce the clonal complexity of the strains and that, in most samples (6/10), only 1 strain will be identified in mixed infections after culture (3). This suggests that mixed infections and clonal complexity are underrepresented in culture-based diagnoses of TB. In support of this suggestion, the results of molecular-based methods that use strain-specific PCR showed that 2.1%–19.0% of patients with active TB in moderate to high incidence countries were simultaneously infected with >2 strains (1,2,4–10).
Possible co-infection of patients with drug-sensitive and drug-resistant M. tuberculosis strains has been described (1,2), and modeling of the effect of such co-infection on the long-term dynamics of tuberculous infection has led to the hypothesis that persons with this type of infection may retain small populations of drug-resistant bacteria that can flourish after the host receives treatment (11). van Rie et al. showed the amplification of a drug-resistant strain after treatment and postulated selection of drug-resistant strains from an initial mixed infection through antimicrobial drug pressure (2). We confirm this hypothesis by combining detailed longitudinal clinical and microbiological observation with the use of novel in vitro growth competition assays to study 2 co-infecting patient strains in the presence and absence of the primary drug used in treatment.

The Study

The 2 M. tuberculosis strains were isolated from a 68-year-old man from Portugal. He did not have HIV and was treated as a confined inpatient, limiting the possibility that this was not a true in vivo mixed infection. Using a novel approach, we correlated in vitro growth and treatment characteristics for the patient strains with the in vivo strain predominance and persistence of a less-fit, drug-resistant strain. All samples were obtained with approval from St. Mary Hospital’s (London, UK) Research Ethics Center (no. 07/H0712/85) and with the patient’s written informed consent.
Details of the patient samples are in the Table. The initial bronchoalveolar lavage smear sample was positive for acid-fast bacilli (AFB); culture results were positive for fully sensitive M. tuberculosis. Treatment with isoniazid, rifampin, ethambutol, and pyrazinamide was begun. Because of the patient’s alcohol use, his treatment was managed on an inpatient basis in a single-patient, negative-pressure room. Two months later, repeat sputum smears were positive for AFB, and culture results were positive for fully sensitive M. tuberculosis. After 4 months of treatment, the patient’s clinical signs had not improved, and his sputum smear was still positive for AFB. Culture results for the sputum sample were positive for M. tuberculosis resistant to isoniazid and ethambutol; a modified treatment regime resolved the infection, and the patient was released the following month, by which time his smear and culture results were negative.

Genetic Variants of Orientia tsutsugamushi in Domestic Rodents, Northern China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Genetic Variants of Orientia tsutsugamushi in Domestic Rodents, Northern China - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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Volume 19, Number 7—July 2013

Dispatch

Genetic Variants of Orientia tsutsugamushi in Domestic Rodents, Northern China

Article Contents

• The Study
• Conclusions
• Acknowledgments
• References
• Figure
• Table
• Suggested Citation

Meng Zhang, Zhong-Tang Zhao , Xian-Jun Wang, Zhong Li, Lei Ding, Shu-Jun Ding, and Hui-Li Yang

Author affiliations: Shandong University, Jinan, People’s Republic of China (M. Zhang, Z.-T. Zhao, L. Ding); Shandong Center for Disease Control and Prevention, Jinan (X.-J. Wang, Z. Li, S.-J. Ding); Tai’an Center for Disease Control and Prevention, Tai’an, China (H.-L. Yang)

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Abstract

We screened Orientia tsutsugamushi from 385 domestic rodents and 19 humans with scrub typhus in rural Tai’an District, Shandong Province, a new scrub typhus epidemic area in northern China. Sequence analysis identified 7 genotypes in the rodents, of which 2 were also identified in the humans.

Orientia tsutsugamushi, the causative agent of scrub typhus, is widely prevalent in the Asia–Pacific region and causes an estimated 1 million cases per year (1). It is characterized by dramatic genetic diversity (2). In the 1960s, complement fixation initially identified O. tsutsugamushi as Karp, Gilliam, and Kato types (3), which are widely used as tested antigens in serologic assays. Since then, >20 antigenic variants of O. tsutsugamushi have been identified by immunologic and molecular methods (2). The 56-kDa type-specific antigen (TSA), which is one of the major immunogens of the agent and is associated with pathogenesis, has been commonly used for type designation (4–6).
Scrub typhus is a traditional tropical rickettsiosis. However, since 1986, it has emerged and spread rapidly in temperate zones; the epidemic season is mainly in autumn and winter (7,8). In the late 1990s, the district of Tai’an, west of Shandong Province, northern China (116°20′–117°59′E, 35°38′–36°28′N), became a new epidemic area of autumn–winter type scrub typhus (9); however, few epidemiologic and molecular investigations of the transmission cycle of the disease have been conducted in this area. We therefore investigated the prevalence of O. tsutsugamushi infection among rural domestic rodents in the newly developed epidemic area, evaluated the genotypic diversity according to the variations in the 56-kDa TSA gene, and explored the genetic relationship between strains circulating among domestic rodents and those infecting humans.

Reducing Visceral Leishmaniasis by Insecticide Impregnation of Bed-Nets, Bangladesh - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Reducing Visceral Leishmaniasis by Insecticide Impregnation of Bed-Nets, Bangladesh - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Suggested citation for this article

Volume 19, Number 7—July 2013

Dispatch

Reducing Visceral Leishmaniasis by Insecticide Impregnation of Bed-Nets, Bangladesh

Article Contents

• The Study
• Conclusions
• Acknowledgments
• References
• Figure 1
• Figure 2
• Table 1
• Table 2
• Technical Appendix [164 KB - 6 pages]
• Suggested Citation

Dinesh Mondal , M. Mamun Huda, Mithun Kumar Karmoker, Debashis Ghosh, Greg Matlashewski, Shah Golam Nabi, and Axel Kroeger

Author affiliations: International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh (D. Mondal, M.M. Huda, M.K. Karmoker, D. Ghosh); World Health Organization, Geneva, Switzerland (G. Matlashewski, A. Kroeger); Directorate General of Health Services of the Government of Bangladesh, Dhaka (S.G. Nabi); Liverpool School of Tropical Medicine, Liverpool, UK (A. Kroeger)

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Abstract

The effect of insecticide-treated materials on reducing visceral leishmaniasis (VL) is disputable. In Bangladesh, we evaluated the effect of a community-based intervention with insecticide impregnation of existing bed-nets in reducing VL incidence. This intervention reduced VL by 66.5%. Widespread bed-net impregnation with slow-release insecticide may control VL in Bangladesh.

The governments of Bangladesh, India, and Nepal have committed to eliminate visceral leishmaniasis (VL) by 2015 (1). Reducing VL incidence by controlling sandflies, the vector of Leishmania spp. parasites, through integrated vector management is a key strategy of elimination programs (2). Community-based intervention with insecticide-treated materials, such as distribution of long-lasting insecticide–treated bed-nets or mass bed-net impregnation programs with slow-release insecticide tablets, could be possible vector-control components of integrated vector management if they are found effective in reducing VL incidence (3). We evaluated the effect of a community-based intervention with impregnation of existing bed-nets in reducing VL incidence in VL-endemic villages of subdistrict (upazila) Godagari, district Rajshahi, Bangladesh.

Prevalence of Nontuberculous Mycobacteria in Cystic Fibrosis Clinics, United Kingdom, 2009 - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Prevalence of Nontuberculous Mycobacteria in Cystic Fibrosis Clinics, United Kingdom, 2009 - Vol. 19 No. 7 - July 2013 - Emerging Infectious Disease journal - CDC

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Polyxeni Potter

Author affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

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Volume 19, Number 7—July 2013

Dispatch

Prevalence of Nontuberculous Mycobacteria in Cystic Fibrosis Clinics, United Kingdom, 2009

Article Contents

• The Study
• Conclusions
• Acknowledgment
• References
• Figure
• Table,
• Technical Appendix [83 KB - 2 pages]
• Suggested Citation

Paul Seddon , Katy Fidler, Sundhya Raman, Hilary Wyatt, Gary Ruiz, Caroline Elston, Felicity Perrin, Khin Gyi, Diana Bilton, Francis Drobniewski, and Melanie Newport

Author affiliations: Royal Alexandra Children’s Hospital, Brighton, UK (P. Seddon, K. Fidler); Brighton and Sussex Medical School, Brighton (K. Fidler, S. Raman, M. Newport); Kings College Hospital, London, UK (H. Wyatt, G. Ruiz, C. Elston, F. Perrin); Royal Brompton Hospital, London (K. Gyi, D. Bilton); Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London (F. Drobniewski)

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Abstract

Incidence of pulmonary infection with nontuberculous mycobacteria (NTM) is increasing among persons with cystic fibrosis (CF). We assessed prevalence and management in CF centers in the United Kingdom and found 5.0% of 3,805 adults and 3.3% of 3,317 children had recently been diagnosed with NTM. Of those, 44% of adults and 47% of children received treatment.

Nontuberculous mycobacteria (NTM) are ubiquitous environmental organisms (1), broadly classifiable into “slow” and “rapid” growers. Many species, especially the slow-growing Mycobacterium avium complex (MAC), are known to cause disseminated disease in immunodeficient persons (2,3). Rapid growers include the phylogenetically similar M. abscessus and M. chelonae, referred to as M. abscessus complex (MABSC). Such organisms have emerged as pathogens in immunocompetent adults, for example, after traumatic limb injuries sustained during the 2004 tsunami in the Indian Ocean (4). NTM have been identified as pulmonary pathogens in immunocompetent middle-aged women with nodular bronchiectasis (5) and older men who smoke with upper lobe cavitation (6). Since the 1990s, NTM have been increasingly isolated from the sputum of patients with cystic fibrosis (CF) (7,8).
CF is the most frequent lethal genetic disorder of White persons, affecting >8,000 persons in the United Kingdom and 30,000 in the United States. Early death is mainly from chronic lung disease caused by persistent lower airway infection and inflammation. Important airway pathogens include Staphylococcus aureus and Pseudomonas aeruginosa, but others, such as NTM, are playing an increasingly recognized role.
A multicenter prospective study of CF patients in the United States (9) found the prevalence of NTM in sputum to be 13%; MAC was the most common species (72%), and M. abscessus was the next most common (16%). Older age was the most significant predictor for a positive sputum culture. A multicenter CF study in France reported a prevalence of 6.6%, showing MABSC to be the most common; MAC was the next most prevalent (10). Single-center studies in Europe have found variable NTM prevalences, from 13.3% in a center in Germany (7) to 3.8% in a center in the United Kingdom (8).
It is often difficult to determine whether isolation of NTM represents colonization or disease that requires treatment. Current American Thoracic Society guidelines (1) are helpful, but application lacks uniformity, and management is complicated by inducible resistance to antibiotics (11).
To determine the optimal management of NTM in CF, we first need to define the extent of the problem and characterize current practice. The aim of this study was to establish the prevalence of NTM infection in the UK CF community, how it is screened for, and how it is managed.

The Study

A single-page questionnaire (Technical Appendix [PDF - 83 KB - 2 pages]) was sent to the lead CF physician in all UK pediatric and adult CF centers identified by the principal UK CF charity, the Cystic Fibrosis Trust, in 2009. Nonresponders were followed up with by email or telephone. The local research ethics committee deemed the study did not require ethical approval.
Results were tabulated and basic statistical analysis performed by using Microsoft Excel 2007 (Microsoft, Redmond, WA, USA). Because M. chelonae and M. abscessus have common phenotypic characteristics and not all samples were fully sequenced by a reference laboratory, we combined these for reporting as MABSC.