Need For Systematic Surveillance Research Articles

Multidrug-resistant phenotype and isolation of a novel SHV- beta-Lactamase variant in a clinical isolate of Enterobacter cloacae.

BackgroundESBL-producing bacteria are a clinical problem in the management of diseases caused by these pathogens. Worldwide, systemic infections with BL enzymes are evolving by mutations from classical bla genes in an intensified manner and they continue to be transferred across species.ResultsE.cloacae BF1417 isolate and its transconjugants gave positive results with the DDST, suggesting the presence of ESBL. Sequence analysis revealed a blaSHV-ESBL-type gene that differs from the gene encoding SHV-1 by five point mutations resulting in three amino acid substitutions in the coding region: C123R, I282T and L286P. This novel SHV-type enzyme was designated SHV-128. The conjugation tests and plasmid characterization showed that the blaSHV-128 is located on a conjugative plasmid IncFII type. Expression studies demonstrated that the above mutations participated in drug resistance, hydrolysis of extended spectrum β-lactam and the change of the isoelectric point of the protein.ConclusionThese findings underscore the diversity by which antibiotic resistance can arise and the evolutionary potential of the clinically important ESBL enzymes. In addition, this study highlights the need for systematic surveillance of ESBL-mediated resistance as well as in clinical areas and communities.

Prevalence of hospital acquired enterococci infections in two primary-care hospitals in Osogbo, Southwestern Nigeria

Enterococci are opportunistic bacteria that become pathogenic when they colonize niches where they are not normally found. Of recent, they have become major cause of nosocomial infections, especially of the bloodstream, urinary tract and surgical sites. The aim of this study is to determine the point-prevalence rate of human enterococci infections among hospitalized patients in Osogbo, Nigeria. The study was conducted between January and June 2009 in two primary-care hospitals in Osogbo and involved a total of 118 patients who developed clinical evidence of infection at least 48 hours after hospital admission. Appropriate clinical samples were collected from the patients after an informed consent and cultured for isolation/biochemical identification of Enterococcus species at the Bacteriology Laboratory of Ladoke Akintola University of Technology, Osogbo using standard microbiological methods. There were 525 hospital admissions within the time frame of the study of which 118 (22.5%) developed hospital acquired infection (HAI); 58 (49.2%) of which cultured positive for bacterial pathogens. Enterococci were isolated from infective focus in 7 patients, giving a prevalence rate of hospital-acquired enterococci infection of 5.9%. Two species of Enterococcus were identified; Enterococcus faecalis from urinary tract infection (UTI) and surgical site infection (SSI) of 6 (85.7%) patients and Enterococcus faecium from UTI in 1 (14.3%) patient. Other bacteria recovered from other infective foci were Klebsiella spp 31.0%, Pseudomonas spp 20.7%, Staphylococcus aureus 17.2%, Escherichia coli 12.1%, Staphylococcus epidermidis 3.4%, Streptococcus pneumoniae 1.7% and Serratia spp 1.7%. All the enterococci isolates were multiply antibiotic resistant, and 42.9% were vancomycin-resistant enterococci (VRE) with the VRE strains showing resistance to wider range of antibiotics than the vancomycin-sensitive strains. Other Gram-positive and Gram negative bacterial isolates also demonstrated multiple resistance to all commonly available antibiotics in this community except E. coli and Pseudomonas spp which were relatively sensitive to ciprofloxacin and ceftazidime. This limited study demonstrated a high prevalence rate of multiple antibiotic resistant enterococci infections among hospitalized patients in this environment. There is need for systematic surveillance of hospitals for enterococci infections; prudent use and rational prescription of antibiotics and stringent measures to reduce the prevalence rate by health education on infection control measures such as isolation, cleaning, disinfection and sterilization.

Transseptal Left Heart Catheterization and the Incidence of Persistent Iatrogenic Atrial Septal Defects

Access to the left atrium for invasive and interventional cardiac procedures requires a transseptal (TS) puncture that creates an iatrogenic atrial septal defect (iASD). The utilization of TS access is increasing in cardiology, and the frequency of iASD is, therefore, likely to increase as well. Here, we discuss the TS technique, review existing series of iASD with regard to incidence and clinical significance of residual iASD, and present emerging techniques utilizing TS access where iASD may result. A PubMed search for "iatrogenic atrial septal defects" was performed to identify prospective series addressing the incidence of iASDs after TS procedures. We identified 10 series with primary attention to iASD. Cases involving TS access included electrophysiology ablation procedures, atrial appendage closure, and percutaneous balloon mitral valvuloplasty. Immediate postprocedural incidence of iASD was as high as 87%, with decreased incidence of residual iASD detected over time. At 18 months of follow-up, up to 15% of iASD cases persisted. Residual iASDs were not associated with clinical sequelae of embolism, cyanosis, or right heart failure. iASDs are frequent following TS access and a majority resolve over time. Available evidence suggests iASDs are well tolerated but late term follow-up is limited. With the increased utilization of TS transcatheter procedures, the frequency and size of iASDs may rise. Understanding the rare but serious clinical implications of iASD and the need for systematic surveillance in the future is warranted.

Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic

In March and early April 2009, a new swine-origin influenza A (H1N1) virus (S-OIV) emerged in Mexico and the United States. During the first few weeks of surveillance, the virus spread worldwide to 30 countries (as of May 11) by human-to-human transmission, causing the World Health Organization to raise its pandemic alert to level 5 of 6. This virus has the potential to develop into the first influenza pandemic of the twenty-first century. Here we use evolutionary analysis to estimate the timescale of the origins and the early development of the S-OIV epidemic. We show that it was derived from several viruses circulating in swine, and that the initial transmission to humans occurred several months before recognition of the outbreak. A phylogenetic estimate of the gaps in genetic surveillance indicates a long period of unsampled ancestry before the S-OIV outbreak, suggesting that the reassortment of swine lineages may have occurred years before emergence in humans, and that the multiple genetic ancestry of S-OIV is not indicative of an artificial origin. Furthermore, the unsampled history of the epidemic means that the nature and location of the genetically closest swine viruses reveal little about the immediate origin of the epidemic, despite the fact that we included a panel of closely related and previously unpublished swine influenza isolates. Our results highlight the need for systematic surveillance of influenza in swine, and provide evidence that the mixing of new genetic elements in swine can result in the emergence of viruses with pandemic potential in humans.

Epidemiology of Pseudomonas aeruginosa and risk factors for carriage acquisition in an intensive care unit

Because of a high prevalence of Pseudomonas aeruginosa infections, we conducted an epidemiological study to assess the need for systematic surveillance, as well as the value of applying barrier precautions toP. aeruginosa carriers. From July 1997 to February 1998, we conducted a prospective cohort study in an 18-bed medical intensive care unit (ICU), which is part of the infectious diseases department in a 1200-bed tertiary-care teaching hospital. Rectal and oropharyngeal swabs were obtained on admission and twice weekly. Acquired strains were genotypically characterized by pulsed-field gel electrophoresis (PFGE). A risk factor analysis for carriage, colonization and infection was performed. Among 269 eligible patients, 116 (43%) were P. aeruginosa carriers, with 46 (17%) detected on admission and 70 (26%) who acquired carriage during their stay in ICU. Among these 70 patients, 29 became colonized (N=13) or developed infection (N=16). Conversely, in the 121 patients who remained free of carriage, no colonization or infection were detected. Genotyping analysis using PFGE was performed for 81/85 (95%) acquired strains in 67 patients. The same genotype I was observed for 58/81 (70%) of these strains issued from 47 patients, and a distinct genotype II affected two other patients (three strains). The last 20 strains were not genetically related. In a multivariate model, mechanical ventilation was associated with the acquisition of P. aeruginosa carriage. Antibiotics ineffective against P. aeruginosa significantly increased the risk of colonization or infection in ICU. Although several recent studies concluded that endogenous sources account for the majority of P. aeruginosa colonizations or infections, we conclude that epidemiology may vary according to the ICU, and that cross-colonization (i.e., exogenous source) may occur and warrant reinforced barrier precautions.

A review of mutual transmission of important infectious diseases between livestock and wildlife in Europe.

Oral vaccination of red foxes against rabies has been practiced in Europe since 1978 and has succeeded in greatly reducing the occurrence of this disease in foxes: this is an example of coordinated activity against a disease that affects both wild and domestic animals as well as humans. Some examples of diseases that affect both domestic and wild animals in Europe are: classical swine fever (hog cholera) in wild boars and domestic swine; myxomatosis and rabbit hemorrhagic disease in domestic and wild rabbits; bovine viral diarrhea (BVD) in cattle and roe deer; contagious ecthyma in domestic sheep and goats and also in, e.g., chamois, muskox, and reindeer; Mycobacterium bovis in cattle, wild boars, badgers, and deer; and brucellosis in a broad range of livestock and wildlife in all European countries. In addition, serological surveys performed in different free-ranging ungulate species revealed the presence of alphaherpesviruses related to bovine herpesvirus-1 in 7 European countries; and a study of malignant catarrhal fever in deer in Germany might indicate that in this case sheep are the main reservoir species. Although many data on infectious diseases are available in various European countries, there is more need for systematic surveillance and coordinated research.

The Emerging Genetic Diversity of HIV

The discovery of highly divergent strains of human immunodeficiency virus (HIV) not reliably detected by a number of commonly used diagnostic tests has underscored the need for effective surveillance to track HIV variants and to direct research and prevention activities. Pathogens such as HIV that mutate extensively present significant challenges to effective monitoring of pathogens and to disease control. To date, relatively few systematic large-scale attempts have been made to characterize and sequence HIV isolates. For most of the world, including the United States, information on the distribution of HIV strains among different population groups is limited. We describe herein the implications resulting from the rapid evolution of HIV and the need for systematic surveillance integrated with laboratory science and applied research. General surveillance guidelines are provided to assist in identifying population groups for screening, in applying descriptive epidemiology and systematic sampling, and in developing and evaluating efficient laboratory testing algorithms. Timely reporting and dissemination of data is also an important element of surveillance efforts. Ultimately, the success of global surveillance network depends on collaboration and on coordination of clinical, laboratory, and epidemiologic efforts.