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PubMedDate not supplied

Pattern of cholera in Raipur: a twelve year appraisal.

Outbreaks of cholera were recorded in Raipur in the years 1970, 1975, 1977 and 1979-1981. Change from V. cholerae classical inaba in 1970 to V. el tor ogawa in 1974 was also observed. The el tor strain is persisting in this area since then. In 1977, antigenic shift to V. el tor inaba was recorded but it again reverted to el tor ogawa which was responsible for outbreaks in 1979-1981. V. cholerae was isolated in most of the months in the years 1975, 1977 and 1980. Almost equal prevalence rates were seen in both sexes as well as in paediatric and adult groups. NAG vibrio were also inoculated. These data suggest endemicity of choloera in Raipur.

Age Factors↗
PubMed1998

Surveillance of an adult intensive care unit for long-term persistence of a multi-resistant strain of Acinetobacter baumannii.

Sporadic infections with Acinetobacter spp., punctuated with prolonged outbreaks of infection involving larger numbers of patients and a particular epidemic strain of Acinetobacter baumannii, have occurred in the adult intensive care unit (ICU) of Nottingham University Hospital since 1985. The aim of this study was to screen patients admitted to the ICU for three or more days during a non-outbreak period in 1994-1995 and to use DNA fingerprinting techniques to compare any isolates of Acinetobacter spp. with isolates obtained from the same ICU during the previous ten years. In the present study, almost 20% of the ICU patients screened during 1994-1995 became colonized with Acinetobacter spp. The commonest species isolated from patients was Acinetobacter baumannii; five different strains were identified by random amplified polymorphic DNA fingerprinting, including the epidemic strain responsible for outbreaks of infection in 1985-1986 and 1992-1993. Environmental sampling yielded Acinetobacter spp. from one or more samples on four occasions; Acinetobacter radioresistens was the commonest species isolated, and Acinetobacter baumannii (not the epidemic strain) was isolated on only one occasion from the environment. The long-term persistence of a potentially epidemic strain in the ICU, even during a non-outbreak period, indicates a need for continued vigilance. Consequently, periodic patient and environmental surveillance, combined with typing of isolates, is recommended for ICUs where significant outbreaks of Acinetobacter infection have occurred in the past.

Acinetobacter↗
PubMed2005

Transcriptional autoregulation by quorum sensing Escherichia coli regulators B and C (QseBC) in enterohaemorrhagic E. coli (EHEC).

The cell-to-cell communication system referred to as quorum sensing (QS) is based on the principle that bacteria secrete hormone-like compounds referred to as autoinducers. Upon reaching a threshold concentration, these autoinducers interact with transcription factors to regulate gene expression. We previously reported that enterohaemorrhagic Escherichia coli (EHEC), which is responsible for outbreaks of bloody diarrhoea, utilizes a QS system to regulate gene transcription. We have also previously shown that the quorum sensing E. coli regulators B and C (QseBC) may act as a two-component system to transcriptionally regulate the expression of flagella and motility. Here, using a reverse transcription polymerase chain reaction (RT-PCR), we show that qseBC are transcribed in an operon. Furthermore, using a qseBC::lacZ transcriptional fusion, we observed that QseB autoactivates its own transcription. In addition, the transcriptional start site of the qseBC promoter responsive to QseBC was mapped, and single-copy and multicopy deletion analyses were performed to determine the minimal region necessary for QseB transcriptional activation. These data allowed us to map an additional transcriptional start site for the qseBC promoter which may allow for a basal level of QseBC expression. Finally, electrophoretic mobility shift assays, competition experiments and DNase I footprints were performed and demonstrated that QseB directly binds to two sites in its own promoter. These results indicate that QseB may act to autoregulate its own transcription through binding to low- and high-affinity sites found in its promoter.

Escherichia coli O157↗
PubMed2000

Outbreak of tuberculosis associated with a church.

Investigation of an outbreak of tuberculosis (TB) in a West Midlands health district in 1999 revealed spread in an extended family network and to church contacts. Within the family four cases of smear positive TB, four cases of smear negative infection, and 14 cases requiring chemoprophylaxis were identified. One of the infectious cases visited a local church on two occasions, which resulted in a further 16 cases of infection including one case of tuberculous meningitis. DNA fingerprinting of isolates from five culture positive cases indicated that the same strain of Mycobacterium tuberculosis was responsible. This outbreak is a reminder that while outbreaks of TB usually arise within households or family networks, where close contact over extended periods provides more opportunity for exposure, community outbreaks of TB can occur after only causal contact.

Adult↗
PubMed2006

"Everything depends on good nursing".

Nurses have always played a vital role in the response to outbreaks of deadly illnesses. The story of Alberta nurses' heroic efforts in the face of the Spanish influenza epidemic of 1918-19, in the absence of public health infrastructure, reminds us of the importance of preparedness. The virus, which accompanied soldiers returning from Europe after the First World War, spread quickly along transportation routes from Eastern Canada to the West. Although many nurses had not yet returned from war service, or were assisting in Halifax following the explosion of 1917, those who were available in Alberta vo unteered without hesitation to care for victims of the virus. In the absence of cure, good nursing care was usually the only treatment for the illness. Recognition of the need for planned response to crises, availability of resources and excellent skills and knowledge prompted nursing leaders to lobby the government for a formal public health system and contributed to the organization of professional nursing associations. In the likely event of another global influenza pandemic, nurses may draw upon the lessons of the past as they once again face the complex challenges of a modern health crisis.

Animals↗
PubMed2006

Psychological responses of pregnant women to an infectious outbreak: a case-control study of the 2003 SARS outbreak in Hong Kong.

OBJECTIVE: The aim of the present study was to examine the behavioral and psychological responses of pregnant women during the 2003 severe acute respiratory syndrome (SARS) outbreak in Hong Kong. METHODS: Ethnographic interviews were first conducted to identify the common psychological and behavioral responses to the outbreak. This was followed by a case-control study of 235 consecutive pregnant women recruited during the SARS epidemic, and a historical cohort of 939 pregnant women recruited a year before the outbreak. Both cohorts completed standardized rating scales on depression, anxiety, and social support. RESULTS: Women in the SARS cohort adopted behavioral strategies to mitigate their risk of contracting infection. However, pregnant women tended to overestimate the risk of contracting SARS and nearly a third of the women were homebound. The anxiety level of the SARS cohort was slightly higher than that of the pre-SARS control. No statistical difference was found between the depression levels of the two cohorts. CONCLUSION: The improved social support experienced by pregnant women during SARS might have buffered the stress associated with an outbreak. However, clinicians should monitor for overestimation of infectious risk among pregnant women.

Adult↗
PubMed2003

Bacteria-host communication: the language of hormones.

The interbacterial communication system known as quorum sensing (QS) utilizes hormone-like compounds referred to as autoinducers to regulate bacterial gene expression. Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 is the agent responsible for outbreaks of bloody diarrhea in several countries. We previously proposed that EHEC uses a QS regulatory system to "sense" that it is within the intestine and activate genes essential for intestinal colonization. The QS system used by EHEC is the LuxS/autoinducer 2 (AI-2) system extensively involved in interspecies communication. The autoinducer AI-2 is a furanosyl borate diester whose synthesis depends on the enzyme LuxS. Here we show that an EHEC luxS mutant, unable to produce the bacterial autoinducer, still responds to a eukaryotic cell signal to activate expression of its virulence genes. We have identified this signal as the hormone epinephrine and show that beta- and alpha-adrenergic antagonists can block the bacterial response to this hormone. Furthermore, using purified and in vitro synthesized AI-2 we showed that AI-2 is not the autoinducer involved in the bacterial signaling. EHEC produces another, previously undescribed autoinducer (AI-3) whose synthesis depends on the presence of LuxS. These results imply a potential cross-communication between the luxS/AI-3 bacterial QS system and the epinephrine host signaling system. Given that eukaryotic cell-to-cell signaling typically occurs through hormones, and that bacterial cell-to-cell signaling occurs through QS, we speculate that QS might be a "language" by which bacteria and host cells communicate.

Bacterial Proteins↗
PubMed1981

A prospective study of response error in food history questionnaires: implications for foodborne outbreak investigation.

To explore the problem of response error in food history data, a prospective study examined the validity of food questionnaire data obtained five days after the study meal. Unobtrusive observation of 64 persons selecting two different foods at a buffet-style luncheon were compared with subsequent histories of food consumption. The predictive value of a positive response was 0.73 for one food and 0.82 for the second food. The response error measures obtained were then applied to data from a published foodborne outbreak to illustrate the impact of predictive value positive and predictive value negative levels on the significance of a food-illness association. Public health workers engaged in food questionnaire administration and analysis must consider response error and should explore methods of reducing this problem through attention to both interviewer-respondent interaction and questionnaire design.

Adult↗
PubMed2005

Patients' request for and emergency physicians' prescription of antimicrobial prophylaxis for anthrax during the 2001 bioterrorism-related outbreak.

BACKGROUND: Inappropriate use of antibiotics by individuals worried about biological agent exposures during bioterrorism events is an important public health concern. However, little is documented about the extent to which individuals with self-identified risk of anthrax exposure approached physicians for antimicrobial prophylaxis during the 2001 bioterrorism attacks in the United States. METHODS: We conducted a telephone survey of randomly selected members of the Pennsylvania Chapter of the American College of Emergency Physicians to assess patients' request for and emergency physicians' prescription of antimicrobial agents during the 2001 anthrax attacks. RESULTS: Ninety-seven physicians completed the survey. Sixty-four (66%) respondents had received requests from patients for anthrax prophylaxis; 16 (25%) of these physicians prescribed antibiotics to a total of 23 patients. Ten physicians prescribed ciprofloxacin while 8 physicians prescribed doxycycline. CONCLUSION: During the 2001 bioterrorist attacks, the majority of the emergency physicians we surveyed encountered patients who requested anthrax prophylaxis. Public fears may lead to a high demand for antibiotic prophylaxis during bioterrorism events. Elucidation of the relationship between public health response to outbreaks and outcomes would yield insights to ease burden on frontline clinicians and guide strategies to control inappropriate antibiotic allocation during bioterrorist events.

Anthrax↗
PubMed2005

Protecting health care workers from SARS and other respiratory pathogens: a review of the infection control literature.

BACKGROUND: Severe Acute Respiratory Syndrome (SARS) was responsible for outbreaks in Canada, China, Hong Kong, Vietnam, and Singapore. SARS focused attention on the adequacy of and compliance with infection control practices in preventing airborne and droplet-spread transmission of infectious agents. METHODS: This paper presents a review of the current scientific knowledge with respect to the efficacy of personal protective equipment in preventing the transmission of respiratory infections. The effectiveness of infection control policies and procedures used in clinical practice is examined. RESULTS: Literature searches were conducted in several databases for articles published in the last 15 years that related to infection control practices, occupational health and safety issues, environmental factors, and other issues of importance in protecting workers against respiratory infections in health care settings. CONCLUSION: Failure to implement appropriate barrier precautions is responsible for most nosocomial transmissions. However, the possibility of a gradation of infectious particles generated by aerosolizing procedures suggests that traditional droplet transmission prevention measures may be inadequate in some settings. Further research is needed in this area.

Humans↗
PubMed1998

Fluorescent amplified-fragment length polymorphism analysis of an outbreak of group A streptococcal invasive disease.

Fluorescent amplified-fragment length polymorphism (FAFLP) analysis was carried out for an outbreak of group A streptococcal (GAS) invasive disease. Streptococcal genomic DNAs were digested with endonucleases EcoRI and MseI, site-specific adaptors were ligated, and PCR amplification was carried out with an EcoRI adaptor-specific primer labelled with fluorescent dye. Amplified fragments of up to 600 bp in size were separated on a polyacrylamide sequencing gel which contained internal size markers in each lane. These data were automatically scanned and analyzed, fragments were precisely sized (+/-1 bp), and electropherograms were generated for each genome with GeneScan 2.1 software. All isolates were compared in this way. Among 27 GAS isolates examined, we found 18 FAFLP profiles, compared with 12 macrorestriction profiles by pulsed-field gel electrophoresis. FAFLP readily distinguished genotypes for two clones of GAS serotype M77 which were responsible for outbreaks of invasive disease in a care-of-the-elderly system. It provided an automated analysis of the whole genome of bacterial isolates. It was reproducible, more discriminatory, and capable of higher throughput than other molecular typing methods. Given agreed conditions, FAFLP would be reproducible between laboratories for rapid characterization of outbreak strains.

Aged↗
PubMedDate not supplied

Plague in Lushoto district, Tanzania, 1980-1988.

Rodents were live-trapped in selected plague-inflicted villages from June 1980 to March 1988. Flea infestation rates were determined and the animals were serologically tested for plague. Clinically suspected and clinically healthy people in the affected areas were similarly tested for plague antibodies. Of 1596 rodent sera tested, 91 (5.7%) were positive for plague. These were mostly from Rattus rattus, Mastomys natalensis, Otomys spp. and Pelomys fallax. A total of 1772 fleas, of which Dinopsyllus lypusus, Xenopsylla brasiliensis and Ctenophthalmus calceatus comprised the largest proportion, was collected from the captured rodents. Total flea indices ranged from 0.67 to 1.12 fleas per rodent. A total of 2809 human cases and a mortality rate of 10.2% were recorded in 1980-1988. It was concluded that most rodent species in the area were suitable reservoirs of plague and that D. lypusus, X. brasiliensis and C. calceatus were probably responsible for transmitting the pathogen. Lack of effective quarantine measures during outbreaks was partly responsible for the spread of the disease to many villages, while inadequate rodent and flea control and poor sanitary measures could be responsible for continued outbreaks of plague in the area.

Animals↗
PubMed1986

Human duodenal mucosal bicarbonate secretion. Evidence for basal secretion and stimulation by hydrochloric acid and a synthetic prostaglandin E1 analogue.

The factors responsible for prevention of duodenal mucosal injury are not known. This series of experiments was performed to determine whether the human duodenum secretes bicarbonate that could prevent mucosal damage. To isolate a 4-cm segment of proximal (i.e., the duodenal bulb) or distal duodenum free of contamination from either gastric or pancreaticobiliary secretion, or both, methods were developed using occlusive balloons. The test segment was perfused with NaCl (2 ml/min, 37 degrees C) containing [14C]PEG as a nonabsorbable marker, and bicarbonate output was quantitated. Mean (+/- SE) basal proximal duodenal bicarbonate output was 143 +/- 17 mumol/cm X h. A 5-min infusion of 25, 50, and 100 mM HCl directly into the isolated proximal duodenal test segment increased bicarbonate output to 167 +/- 29, 199 +/- 19, and 278 +/- 49 mumol/cm X h, respectively, during the hour after acidification. Distal duodenal acidification (25, 50, and 100 mM) also increased bicarbonate output from the isolated proximal duodenal test segment. A synthetic prostaglandin E1 analogue, misoprostol (1.67-13.3 micrograms/min), infused directly into proximal or distal test segments significantly stimulated bicarbonate outbreak; peak responses were 644 +/- 35 mumol/cm X h and 171 +/- 20 mumol/cm X h (p less than 0.001), respectively. Thus, in humans, the proximal and distal duodenal mucosa secretes bicarbonate at rest; direct acidification of the proximal duodenum stimulates bicarbonate output; acidification of the distal duodenum beyond the isolated test segment also increased proximal duodenal bicarbonate output; and a synthetic prostaglandin E1 analogue stimulated both proximal and distal bicarbonate output; however, distal duodenal bicarbonate output was significantly less, indicating a proximal-to-distal gradient in bicarbonate secretion.

Adult↗
PubMed1987

[Differentiation of equine influenza viruses subtype 2 with monoclonal antibodies].

Infections and clinical diseases caused by equine 2 influenza A viruses are observed worldwide. The frequency of these outbreaks supports the hypothesis that antigenic variation of the surface proteins may play an important role. For the demonstration of these variations, monoclonal antibodies (Mabs) were prepared. They are directed against the hemagglutinin or the neuraminidase of the prototype strain a/eq/Miami/1/63. In hemagglutination-inhibition assays with Mabs two reaction patterns were observed: four Mabs inhibited 14 out of 17 strains tested. Another Mab recognized the hemagglutinin of only 4 strains. One strain was not inhibited by any of the Mabs. This reaction pattern was not changed by purification of the Mabs using different techniques. Following tween 80/ether treatment of some strains, the Mab reacting more strain-specific had higher titers against the four closely related strains. Tween 80/ether treatment did not affect the titers of the Mabs reacting more subtype-specific. Analysis of the neuraminidase of 17 strains revealed a marked variation in two strains. Different purification procedures had some influence on the titers of the Mabs but did not alter the pattern of the reaction. The antigenic variation of surface proteins detected by Mabs are not seen so clearly when conventional antisera are used. Therefore, antigenic variations are probably not responsible for outbreaks of equine influenza in vaccinated animals.

Animals↗
PubMed2005

[Multiple Ebola virus haemorrhagic fever outbreaks in Gabon, from October 2001 to April 2002].

Outbreaks of Ebola virus haemorrhagic fever have been reported from 1994 to 1996 in the province of Ogooué Ivindo, a forest zone situated in the Northeast of Gabon. Each time, the great primates had been identified as the initial source of human infection. End of November 2001 a new alert came from this province, rapidly confirmed as a EVHV outbreak. The response was given by the Ministry of Health with the help of an international team under the aegis of WHO. An active monitoring system was implemented in the three districts hit by the epidemic (Zadié, Ivindo and Mpassa) to organize the detection of cases and their follow-up. A case definition has been set up, the suspected cases were isolated at hospital, at home or in lazarets and serological tests were performed. These tests consisted of the detection of antigen or specific IgG and the RT-PCR. A classification of cases was made according to the results of biological tests, clinical and epidemiological data. The contact subjects were kept watch over for 21 days. 65 cases were recorded among which 53 deaths. The first human case, a hunter died on the 28th of October 2001. The epidemic spreads over through family transmission and nosocomial contamination. Four distinct primary foci have been identified together with an isolated case situated in the South East of Gabon, 580 km away from the epicenter. Deaths happened within a delay of 6 days. The last death has been recorded on the 22nd of March 2002 and the end of the outbreak was declared on the 6th of May 2002. The epidemic spreads over the Gabon just next. Unexplained deaths of animals had been mentionned in the nearby forests as soon as August 2001: great primates and cephalophus. Samples taken from their carcasses confirmed a concomitant animal epidemic.

Animals↗
PubMed2001

Quorum sensing is a global regulatory mechanism in enterohemorrhagic Escherichia coli O157:H7.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for outbreaks of bloody diarrhea and hemolytic-uremic syndrome in many countries. EHEC virulence mechanisms include the production of Shiga toxins (Stx) and formation of attaching and effacing (AE) lesions on intestinal epithelial cells. We recently reported that genes involved in the formation of the AE lesion were regulated by quorum sensing through autoinducer-2, which is synthesized by the product of the luxS gene. In this study we hybridized an E. coli gene array with cDNA synthesized from RNA that was extracted from EHEC strain 86-24 and its isogenic luxS mutant. We observed that 404 genes were regulated by luxS at least fivefold, which comprises approximately 10% of the array genes; 235 of these genes were up-regulated and 169 were down-regulated in the wild-type strain compared to in the luxS mutant. Down-regulated genes included several involved in cell division, as well as ribosomal and tRNA genes. Consistent with this pattern of gene expression, the luxS mutant grows faster than the wild-type strain (generation times of 37.5 and 60 min, respectively, in Dulbecco modified Eagle medium). Up-regulated genes included several involved in the expression and assembly of flagella, motility, and chemotaxis. Using operon::lacZ fusions to class I, II, and III flagellar genes, we were able to confirm this transcriptional regulation. We also observed fewer flagella by Western blotting and electron microscopy and decreased motility halos in semisolid agar in the luxS mutant. The average swimming speeds for the wild-type strain and the luxS mutant are 12.5 and 6.6 microm/s, respectively. We also observed an increase in the production of Stx due to quorum sensing. Genes encoding Stx, which are transcribed along with lambda-like phage genes, are induced by an SOS response, and genes involved in the SOS response were also regulated by quorum sensing. These results indicate that quorum sensing is a global regulatory mechanism for basic physiological functions of E. coli as well as for virulence factors.

Bacterial Proteins↗
PubMed2004

Fragmentation patterns of selected ergot alkaloids by electrospray ionization tandem quadrupole mass spectrometry.

Tall fescue toxicosis and other maladies in livestock result from the ingestion of vasoconstrictive ergot alkaloids produced by fungal endophytes associated symbiotically with the grass. In order to facilitate future analyses of grass extracts considered responsible for outbreak of related livestock diseases, we examined the electrospray ionization mass spectra of specific ergot alkaloids under conditions that permit protonation. Our purposes were both to record the spectra with interpretation of mechanisms of fragmentation and to derive commonalities that would allow the prediction of mass spectra of related compounds for which standards were not readily available. With [M + H](+) values in parentheses, water-insoluble lysergic acid peptide ergot derivatives ergovaline (m/z 534), ergotamine (m/z 582), ergocornine (m/z 562), ergocryptine (m/z 576) and ergocrystine (m/z 610) exhibited a consistent loss of water (-18 u) from the C-12' alpha-hydroxy functionality. Of this group, ergovaline and ergotamine generated an m/z 320 fragment deriving from cleavage of ring E amide and ether functions with retention of the peptide ring system methyl group. Ergocornine, ergocryptine and ergocrystine similarly formed an m/z 348 fragment with retention of isopropyl. These assignments were supported by the lack of similar fragments from the water-soluble ergot ergonovine, which lacks a peptide ring system. Clavine-type ergot alkaloids lysergic acid and lysergol lack any substituents beyond simple ones directly on the C-8 position and, similarly to ergonovine, lack significant fragments at m/z 268, 251 and 225 shared by the peptide ergot alkaloids.

Animal Feed↗