Large Infection Outbreak Research Articles

Should tularemia be considered a particularly dangerous infection?

Tularemia is a widespread bacterial zoonotic infection in the world, the causative agent of it in our country is classified as pathogenicity group 2, which corresponds to group 3 according to the international classification for laboratory services. F. tularensis is considered a potential agent of category A bioterrorism. The review presents current information about the causative agent of tularemia, the features of the clinical course of the infection and the incidence rate associated with its different subtypes. The possibilities of treatment and prevention of the disease are highlighted. The material is presented from the point of view of whether the infection meets the criteria for a particularly dangerous disease. The species includes 4 subspecies, of which only one, present only in some states of the United States and probably the evolutionarily oldest, is assessed as highly virulent. The subspecies most widespread on the European continent is classified as moderately virulent and causes diseases that do not meet the criteria for a particularly dangerous disease in terms of severe and mortality rate. There is a list of drugs that are quite effective against the causative agent of tularemia, provided they are prescribed in a timely manner. The incidence of tularemia in countries where it is registered does not exceed sporadic levels. However, a feature of the pathogen is plasticity in the external environment which determines the long-term preservation of the epizootic potential of natural foci. In some years large outbreaks of infection occur, often in the absence of visible risk factors. The possibilities of specific and nonspecific prevention are limited and can reduce the risk of infection of the population only with a timely, quick and adequate response to changing situations. In various countries work is underway to create vaccines on different technological platforms, but currently only Russia, Belarus and Kazakhstan use the live attenuated vaccine. Although by wild strains is not a particularly dangerous disease, it requires close surveillance.

Letter From Australia: A Never-Ending Pandemic?

Australia has faced a trajectory of COVID-19 unlike that seen in other nations. The first Australian cases occurred in January 2020 among tourists from China, yet most regions of Australia then had prolonged periods of almost complete absence of COVID-19 transmission. After 20 months of the pandemic, with a population roughly 10% that of the United States, Australia had a little more than 80 000 infections and 1128 deaths, whereas at the same time, the United States had more than 41 million infections and 666 407 deaths (1). This pattern continued until mid-2021, when major cities experienced transmission of the Delta (B.1.617.2) variant and recent large outbreaks of infection, which may foretell a different future. Of course, “large” in Australia is relative to zero—the current outbreaks in Sydney and Melbourne mean 100 to 1000 cases per day. We reflect on the successes and challenges of Australia's pandemic response and suggest lessons that can be learned.

Laboratory-confirmed bloodstream infections in two large neonatal units in sub-Saharan Africa

BackgroundEpidemiological data on neonatal bloodstream infections (BSI) in sub-Saharan Africa are extremely limited. MethodsA comparative analysis of laboratory-confirmed neonatal BSI episodes was conducted retrospectively in two large neonatal units in Botswana and South Africa (January 1 to December 31, 2017). Routine laboratory and ward register data were used to determine BSI rates, the pathogen spectrum, and BSI outcomes. ResultsIn 2017, the Princess Marina Hospital (PMH) and Tygerberg Hospital (TBH) neonatal units admitted 1187 and 2826 neonates, respectively. The BSI incidence rate was 12.1/1000 patient-days (95% confidence interval (CI) 10.2–14.3) at PMH and 3.5/1000 patient-days (95% CI 2.9–4.1) at TBH (p < 0.0001). Most BSI episodes were hospital-acquired (260/284; 91.6%). The blood culture contamination rate was substantially higher at PMH than TBH (152/1116 (13.6%) vs 122/2559 (4.8%); p < 0.001). The crude mortality rate in neonates with BSI was 21.2% (53/250) and significantly higher at TBH than PMH (38/128 (29.7%) vs 15/122 (12.3%), p = 0.001). Factors independently associated with death were birth weight <1500 g (adjusted odds ratio (aOR) 2.8, 95% CI 1.3–6.4; p = 0.02) and male sex (aOR 2.1, 95% CI 1.1–3.7; p = 0.01). Klebsiella pneumoniae was the dominant BSI pathogen in both units, accounting for two-thirds of BSI, and was associated with a large infection outbreak at PMH. Antibiotic resistance rates were substantial in both neonatal units, particularly for K. pneumoniae (98/122 (80.3%), extended-spectrum beta-lactamase (ESBL)-producers) and Staphylococcus aureus (22/33 (66.7%), methicillin-resistant). ConclusionsBSI rates and associated mortality were substantial in these two neonatal units in sub-Saharan Africa. ESBL-producing K. pneumoniae remains a leading BSI and outbreak pathogen.

Anti-adhesive activity of a Vaccinium corymbosum polyphenolic extract targeting intestinal colonization by Klebsiella pneumoniae

The therapeutic effect of Vaccinium polyphenols against uropathogens has been widely studied. Most attention has focused on the antimicrobial activity against P-fimbriated Escherichia coli strains. The present study investigated the anti-adhesive and anti-biofilm activity of a saline extract of blueberry (Vaccinium corymbosum) targeting intestinal colonization by a highly adherent Klebsiella pneumoniae strain. This strain, responsible for a large outbreak of infection in Spain, was selected on the basis of its remarkable capacity to colonize the gastrointestinal tract of patients.The blueberry extract was obtained using a medium scale ambient temperature system (MSAT) in a novel approach based on the use of an aqueous solvent and addition of mineral salts. The polyphenolic content was determined by liquid chromatography coupled to tandem mass-spectrometry (LC–MS/MS). The findings confirmed that the blueberry extract is a rich source of phenolic compounds, including the most polar polyphenols (mostly non-flavonoids), intermediate polarity compounds (flavan-3-ols and most procyanidins) and low polarity compounds (flavonols and anthocyanins). The extract significantly inhibited biofilm formation and bacterial adhesion to HT-29 colorectal cells by a highly adherent multidrug-resistant K. pneumoniae. Although some individual anthocyanidins (malvidin, delphinidin and cyanidin) and one hydroxycinnamic acid (caffeic acid) proved capable of reducing bacterial adhesion, the unfractionated extract was more active than any of the individual polyphenolic compounds. In addition, the extract displayed considerable potential as an intestinal decolonization treatment in a murine model. The study findings demonstrate the potential value of the V. corymbosum extract as an alternative treatment for K. pneumoniae infections.

Anti SARS-CoV-2 antibodies monitoring in a group of residents in a long term care facility during COVID-19 pandemic peak.

Objectives Clinical laboratories plays a key role in screening, diagnosis and containment of the Coronavirus 2019 infection epidemic. The etiological diagnosis presupposes the isolation of virus genetic material in the patient's biological sample but laboratory diagnostics also make use of searching possibility for immunoglobulin (Ig)G, IgM classes antibodies. The characteristics of the antibody response are not yet completely clear. Methods This study describes a serological monitoring of subjects, elderly nursing care residence guests, interested by a very large infection outbreak. After first nasopharyngeal swab, all the positive subjects (43) were monitored for the persistence of the virus infection through nasopharyngeal swab after 20days (16-24), 32days (28-36) and after 49days (47-50). At the same time, during the second (day 32) and third (day 49) follow up, all the guests were investigated for IgM and IgG anti SARS-CoV-2 antibodies, by using a quantitative chemiluminescence method. Results Thirty two days after performing the first diagnostic swab, 39 of 43 patients (90%) had IgG higher than the cut off value. After 49days the four patients with negative IgG were still negative. The comparison of the levels of IgG-Ab between the controls shows a significant decrease in concentrations (-10%). Conclusions Our study confirms that in most patients affected by COVID-19 there is a typical antibody response with IgG-Ab present in 90% of nursing care COVID-19 positive residence guests. For IgM-Ab only 23% of tested subjects were positive on the 32nd and 49th day of illness, always in parallel with the IgG-Ab positivity.

Assessment of Implementation of Occupational Infection Prevention of The Employee Wellness Program among a Group Of Healthcare Workers in Pediatrics Hospital of Ain Shams University, Cairo, Egypt

Abstract Background Healthcare workers (HCWs) are exposed every day to multiple occupational hazards, the most common being the risk of exposure to occupational infections. Occupational infection prevention of the healthcare workers is a substantial issue not only to protect them, but also to protect their patients. If the risk posed by infection in health care workers is not recognized and addressed, there is the potential for large outbreaks of infection among staff and patients. Aim of Study Assessment of implementation of occupational infection prevention of the employee wellness program among healthcare workers in pediatrics hospital of Ain Shams University, Cairo, Egypt. Subjects and Methods A descriptive study was conducted and a structured self-administered aided questionnaire was used to collect data from 110 healthcare workers in the pediatrics hospital at Ain Shams University in Cairo to assess the pre-employment procedures, investigations, infection control training provided by the hospital and post exposure management procedure. Results Around half of the participants (48.2%) reported that they had undergone the pre-employment screening procedures. The majority of participants (85.4%) received infection control training at the hospital. Most of the participants didn’t receive the appropriate management after needle stick injury. Conclusion and Recommendations the current system followed in the Pediatrics hospital does not adequately implement all of the essential elements of the employee wellness program and needs to be improved. Co-ordination between the occupational health unit and infection control department should be done to improve the implementation of other elements of the employee wellness program to protect healthcare workers from occupational infections.

Nosocomial outbreaks caused by Acinetobacter baumannii and Pseudomonas aeruginosa: Results of a systematic review

Large outbreaks of infection by Acinetobacter baumannii and Pseudomonas aeruginosa have been reported. This research compares characteristics of such outbreaks. Determination of risk factors for the occurrence and appropriate infection control measures. The Outbreak Database, PubMed, and reference lists of identified articles were used. Key words included nosocomial and (outbreak or epidemic) and (aeruginosa or baumannii). Articles were included if they describe distinct outbreak(s) caused by A baumannii or P aeruginosa and were published between 2000 and 2015. There were no further restrictions with respect to language or type of article. One hundred fifty outbreaks by A baumannii and 131 outbreaks by P aeruginosa were included, including multidrug-resistant strains in 113 Acinetobacter and 49 Pseudomonas outbreaks. Acinetobacter outbreaks were mainly reported from intensive care units, after use of antibiotics, during mechanical ventilation, and presented with a mortality rate of 47% compared with 23% by Pseudomonas. Resistance did not alter mortality by either species. Most infection control measures were implemented or enforced more often in Acinetobacter outbreaks. These findings should support staff in infection control departments and on wards if an outbreak is suspected. Better adherence to the Outbreak Reports and Intervention Studies of Nosocomial Infection guidelines in outbreak reporting is necessary. A precise definition of multidrug resistance for Acinetobacter and Pseudomonas is lacking.

Meningitis por Streptococcus suis: ¿una zoonosis emergente?

Streptococcus suis is an important pathogen associated with a wide range of diseases in pigs, constituting one of the most important problems of the swine industry around the world.However, infection with S.suis in humans is very rare and is considered an unusual zoonosis because from 1968 until 2004 had described only around 250 cases around the world.The emergence of some very large outbreaks of infection with S.suis in Europe and Southeast Asia from the year 2005, and the increase in the incidence of cases in other European countries, has made to think that we can find about a process of emergence of these infections.S.suis is a Gram-positive facultative anaerobic coccus, belonging to R, S, and T Lancefield groups. Until recently, there have been major difficulties in the identification and differentiation of this organism of other Streptococcus species, what could be the cause of an underestimation of these infections. It's currently with diagnostic tools and molecular typing that allow a better characterization of the isolates.The most frequent S.suis in humans infection is meningitis, but endocarditis, pneumonia, cellulitis, rhabdomyolysis, arthritis, spondylodiscitis, abscess epidural, peritonitis, enteritis, endophthalmitis, uveitis, septicemia with septic shock and multiorgan failure streptococcal toxic shock syndrome have also been reported.In our country less than 20 cases of S.suis infection have been documented, so we believe interest communicate a new case of S.suis meningitis.

A qualitative risk assessment of the microbiological risks to consumers from the production and consumption of uneviscerated and eviscerated small game birds in the UK

Since the beginning of the 21st century, consumption of wild game birds has been increasing, concurrent with a rise in consumer interest in free-range and ‘healthy-eating’ foodstuffs. Game birds can carry zoonotic pathogens, predominantly within the viscera. Whilst removal of the viscera is normal practice during the dressing of game birds, there is a specialised market in the UK for certain small game birds that are consumed uneviscerated. This qualitative risk assessment evaluates the risks to the consumer from the production and consumption of both uneviscerated and eviscerated small game birds for Salmonella spp., Escherichia coli (verotoxigenic), E. coli (antimicrobial resistant), Campylobacter spp., Toxoplasma gondii, Chlamydophila psittaci and Listeria monocytogenes. Whilst most pathogen/bird combinations were considered to have a very low risk, results suggest that Campylobacter spp. and T. gondii can pose an increased risk to consumers for some species of wild game birds. There was no greater risk associated with the consumption of uneviscerated game birds than for eviscerated birds. In some cases, the risk from eviscerated birds may even be slightly higher, as the risk of cross-contamination during evisceration can outweigh the reduction in pathogenic organisms due to removal of the viscera. Additionally, the current low frequency of consumption of uneviscerated game birds of most species reduced the overall risk estimate for these birds. If there is an increased frequency of consumption in the future, then this risk should be re-examined. Assuming a general level of compliance with regulations and basic hygiene practices, the results suggested that large outbreaks of infection among UK consumers are unlikely, but sporadic, infectious events could occur due to combinations of ‘rare-event, hygiene-related issues’ in the ‘field-to-fork’ chain and/or inadequate cooking of the bird.

Whole genome sequence comparison of vtx2-converting phages from Enteroaggregative Haemorrhagic Escherichia coli strains.

BackgroundEnteroaggregative Haemorrhagic E. coli (EAHEC) is a new pathogenic group of E. coli characterized by the presence of a vtx2-phage integrated in the genomic backbone of Enteroaggregative E. coli (EAggEC). So far, four distinct EAHEC serotypes have been described that caused, beside the large outbreak of infection occurred in Germany in 2011, a small outbreak and six sporadic cases of HUS in the time span 1992–2012. In the present work we determined the whole genome sequence of the vtx2-phage, termed Phi-191, present in the first described EAHEC O111:H2 isolated in France in 1992 and compared it with those of the vtx-phages whose sequences were available.ResultsThe whole genome sequence of the Phi-191 phage was identical to that of the vtx2-phage P13374 present in the EAHEC O104:H4 strain isolated during the German outbreak 20 years later. Moreover, it was also almost identical to those of the other vtx2-phages of EAHEC O104:H4 strains described so far. Conversely, the Phi-191 phage appeared to be different from the vtx2-phage carried by the EAHEC O111:H21 isolated in the Northern Ireland in 2012.The comparison of the vtx2-phages sequences from EAHEC strains with those from the vtx-phages of typical Verocytotoxin-producing E. coli strains showed the presence of a 900 bp sequence uniquely associated with EAHEC phages and encoding a tail fiber.ConclusionsAt least two different vtx2-phages, both characterized by the presence of a peculiar tail fiber-coding gene, intervened in the emergence of EAHEC. The finding of an identical vtx2-phage in two EAggEC strains isolated after 20 years in spite of the high variability described for vtx-phages is unexpected and suggests that such vtx2-phages are kept under a strong selective pressure.The observation that different EAHEC infections have been traced back to countries where EAggEC infections are endemic and the treatment of human sewage is often ineffective suggests that such countries may represent the cradle for the emergence of the EAHEC pathotype. In these regions, EAggEC of human origin can extensively contaminate the environment where they can meet free vtx-phages likely spread by ruminants excreta.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2164-15-574) contains supplementary material, which is available to authorized users.

OXA-24 Carbapenemase Gene Flanked by XerC/XerD-Like Recombination Sites in Different Plasmids from Different Acinetobacter Species Isolated during a Nosocomial Outbreak

A clinical strain of Acinetobacter calcoaceticus resistant to carbapenems was isolated from a blood culture sample from an inpatient in a hospital in Madrid (Spain) during a large outbreak of infection (affecting more than 300 inpatients), caused by a multidrug-resistant Acinetobacter baumannii clone. The carbapenem resistance in both the A. calcoaceticus and A. baumannii clones was due to a bla(OXA-24) gene harbored in different plasmids. The plasmids were fully sequenced, revealing the presence of site-specific recombination binding sites putatively involved in mobilization of the bla(OXA-24) gene. Comparison of plasmids contained in the two strains revealed possible horizontal transmission of resistance genes between the Acinetobacter species.

What is the role of antimicrobial resistance in the new epidemic of Clostridium difficile?

The epidemiology of Clostridium difficile infection (CDI) has changed in recent years, with the occurrence of large outbreaks of infection associated with the emergence of ‘hypervirulent’ strains, particularly PCR ribotype 027. There has been much speculation as to the nature of the factors responsible for driving the new epidemic of CDI, and various hypotheses have been proposed. These include increases in the size of the population at risk of CDI and/or their susceptibility to infection, increased exposure to the organism, and changes in the virulence/ transmissibility of the pathogen. Resistance to a range of antimicrobial agents, including the fluoroquinolones, is a common feature of these newly emerged strains. This article considers the part antimicrobial resistance may play as a driver for the observed changes in the epidemiology of CDI and presents a model that would support such a role. However, the paucity of definitive evidence for a causal role and the complexity of the epidemiology of CDI are acknowledged. It may be more accurate to view antimicrobial resistance as one of a range of factors which interact to alter the parameters of the ‘CDI equation’, and thereby determine the size of the CDI problem associated with any given emerging subtype of C. difficile.

Epidemiologic, Clinical, and Economic Evaluation of an Outbreak of Clonal Multidrug-ResistantAcinetobacter baumanniiInfection in a Surgical Intensive Care Unit

To determine risk factors for acquisition of multidrug-resistant (MDR) Acinetobacter baumannii infection during an outbreak, to describe the clinical manifestations of infection, and to ascertain the cost of infection. Case-control study. Surgical intensive care unit in a 400-bed urban teaching hospital and level 1 trauma center. Case patients received a diagnosis of infection due to A. baumannii isolates with a unique pattern of drug resistance (ie, susceptible to imipenem, variably susceptible to aminoglycosides, and resistant to all other antibiotics) between December 1, 2004, and August 31, 2005. Case patients were matched 1 : 1 with concurrently hospitalized control patients. Isolates' genetic relatedness was established by pulsed-field gel electrophoresis. Sixty-seven patients met the inclusion criteria. Case and control patients were similar with respect to age, duration of hospitalization, and Charlson comorbidity score. MDR A. baumannii infections included ventilator-associated pneumonia (in 56.7% of patients), bacteremia (in 25.4%), postoperative wound infections (in 25.4%), central venous catheter-associated infections (in 20.9%), and urinary tract infections (in 10.4%). Conditional multiple logistic regression was used to determine statistically significant risk factors on the basis of results from the bivariate analyses. The duration of hospitalization and healthcare charges were modeled by multiple linear regression. Significant risk factors included higher Acute Physiology and Chronic Health Evaluation II score (odds ratio [OR], 1.1 per point increase; P=.06), duration of intubation (OR, 1.4 per day intubated; P<.01), exposure to bronchoscopy (OR, 22.7; P=.03), presence of chronic pulmonary disease (OR, 77.7; P=.02), receipt of fluconazole (OR, 73.3; P<.01), and receipt of levofloxacin (OR, 11.5; P=.02). Case patients had a mean of $60,913 in attributable excess patient charges and a mean of 13 excess hospital days. Infection control measures included the following: limitations on the performance of pulsatile lavage wound debridement, the removal of items with upholstered surfaces, and the implementation of contact isolation for patients with suspected MDR A. baumannii infection. This large outbreak of infection due to clonal MDR A. baumannii caused significant morbidity and expense. Aerosolization of MDR A. baumannii during pulsatile lavage debridement of infected wounds and during the management of respiratory secretions from colonized and infected patients may promote widespread environmental contamination. Multifaceted infection control interventions were associated with a decrease in the number of MDR A. baumannii isolates recovered from patients.

Large Outbreak of Infection and Colonization with Gram-Negative Pathogens Carrying the Metallo-β-Lactamase Gene blaIMP-4 at a 320-Bed Tertiary Hospital in Australia

A large outbreak of infection and colonization with multiple genera of gram-negative bacilli carrying the metallo- beta -lactamase gene bla(IMP-4) occurred in a 36-bed intensive care unit at a tertiary hospital in Australia. The organisms emerged rapidly, caused severe infections, and contributed to mortality. Controlling the spread of these organisms remains a challenge for all staff involved.

Outbreak of Chlamydia pneumoniae Infection in a Japanese Nursing Home, 1999-2000

To identify risk factors for infection and severe illness due to Chlamydia pneumoniae. To identify risk factors for infection, we conducted a case-control study among nursing home residents who had onset of symptoms during December 1, 1999, to February 20, 2000. To identify risk factors for severe illness among nursing home residents, we conducted a retrospective cohort study. A nursing home providing long-term and day care services for elderly patients in Japan.Participants. Fifty-nine residents and 41 staff members of a nursing home. The attack rates for respiratory illness were 53% (31 of 59) among residents and 22% (9 of 41) among staff. Infection was confirmed in 15 resident and 2 staff case patients by isolation of C. pneumoniae from nasal swab specimens. Fifteen resident case patients developed severe illness (ie, bronchitis, pneumonia, and hypoxia); one case patient died. The median age of resident case patients was 87 years. We could identify neither the source of the outbreak nor significant risk factors for infection and severe illness in residents. However, residents with a higher level of physical activity were more likely to become infected, whereas older residents (aged more than 85 years) and those with a lower level of physical activity were more likely to develop severe illness (P>.05). Contact with residents was a risk factor for infection in staff (relative risk, undefined; P=.04). C. pneumoniae can cause large outbreaks of infection and severe illness among elderly persons, and its transmission is likely to be enhanced by close contacts among people in nursing homes. Therefore, early detection of an outbreak by means of better surveillance, and subsequent isolation of patients, may be effective control measures.

A European outbreak of Salmonella enterica serotype Typhimurium definitive phage type 204b in 2000

To describe the clinical, epidemiologic and microbiological features of a large outbreak of infection with a multiresistant Salmonella enterica serotype Typhimurium definitive type DT204b infection involving at least 392 people in five European countries. Icelandic public-health doctors responded to a report on an Internet news site of an outbreak of infection with a multiresistant strain of Typhimurium DT104 in England by contacting the Public Health Laboratory Service (PHLS) Communicable Disease Surveillance Centre (CDSC). An international alert was sent out through Enter-net. All strains from England & Wales, The Netherlands, Scotland and Germany, and 17 of the outbreak isolates from Iceland, were phage-typed, screened for antimicrobial resistance, and subjected to molecular typing. Hypothesis-generating interviews were conducted, followed by case-control studies performed in Iceland and England. Isolates from cases in Iceland, England and Wales, The Netherlands, Scotland and Germany were identified as Typhimurium DT204b. The antimicrobial resistance pattern was ACGNeKSSuTTmNxCpL. All strains tested displayed an identical plasmid profile. Strains from five cases in England & Wales and five cases in Iceland possessed identical pulsed-field profiles. Although a common source was suspected, only Iceland implicated imported lettuce as a vehicle, with an analytic epidemiologic study (OR = 40.8; P = 0.005; 95% CI 2.7-3175). The identification of international outbreaks, necessary for investigation and control, can be facilitated by standardized phage-typing techniques, the electronic transfer of molecular typing patterns, formal and informal links established through international surveillance networks, and the early reporting of national outbreaks to such networks.