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PubMed1995

Characterization of SRSVs using RT-PCR and a new antigen ELISA.

Stool samples from 451 patients involved in volunteer studies, 26 outbreaks and approximately 175 sporadic cases of acute gastroenteritis from different geographical locations in the world were tested for Norwalk virus (NV) using a newly developed antigen ELISA and RT-PCR. NV was detected in most outbreaks previously characterized as being of NV origin. Overall, a low number of positives for NV was obtained using either RT-PCR with primers that amplified a unique region of the genome, or an ELISA with hyperimmune antisera made to the baculovirus-expressed recombinant NV capsid. However, a significant number of positives was obtained when these samples were tested by RT-PCR using primers that amplified the more highly conserved regions of the genome. Sequence analysis of the amplified viral cDNAs indicated that small round structured viruses (SRSVs) with a wide range of variable genomic sequences (44-87% nucleotide and 31-99% amino acid similarity to the 8Flla NV genome sequence) were responsible for these outbreaks. Several recent outbreaks from the US, Japan and the UK were related to the Snow Mountain Agent (SMA) by sequence analyses. Continued accumulation of sequence information will facilitate the design of new primers for virus detection and increase our understanding of the relationships and epidemiology of these viruses from different sources.

Amino Acid Sequence↗

PubMed2001

Molecular characterization of Newcastle disease viruses isolated from recent outbreaks in Taiwan.

A reverse transcription-polymerase chain reaction (RT-PCR) was described which amplified a portion of the F and HN genes of Newcastle disease virus (NDV) isolated from recent outbreaks in Taiwan. The F protein plays an important role in determining the virulence of NDV strains. Sequencing of a region specifying the F protein cleavage site was therefore undertaken and this verified the correlation between deduced amino sequences and pathogenicity. Analysis of the deduced amino acid sequences of the F protein cleavage site showed that all recent Taiwanese isolates in 1999 were velogenic viruses. All the virulent viruses have the amino acid sequence 112RRQKR116 for the C-terminus of the F2 protein and phenylanine (F) at the N-terminus of the F1 protein, residue 117. A phylogenetic tree based on the nucleotide sequences of the F gene revealed that recent Taiwanese NDV isolates responsible for recent outbreaks were classified into two distant genotypes (VI and VII). Genotype VI virus is the first finding in Taiwan and has a highly genetic similarity to European isolates, suggesting that they might have originated from a common ancestor.

Amino Acid Sequence↗

PubMed1980

Technical problems in determining safe re-entry intervals.

Organophosphate pesticide residues have been responsible for periodic outbreaks of acute intoxication among California fieldworkers for over 30 years. In 1971, California established 're-entry intervals' to protect workers against overexposure to these residues. These intervals are stipulated times which must elapse between pesticide application and entry into the field for work involving substantial foliar or soil contact. The re-entry strategy depends upon a relatively predictable relation between time post-application and the level of the pesticide residue. It now appears that there are thiophosphates for which the residue hazard is not related to time in a stable way. This circumstance and the continued occurrence of poisoning incidents have focused attention on the quantitative aspects of the relationships between pesticide residue and toxicological response in humans. In the last decade, considerable progress has been made in elucidating these relationships and it now appears to be possible to outline the data requirements for a comprehensive regulatory solution to this longstanding occupational health problem.

Agricultural Workers' Diseases↗

PubMed1975

The Middleton outbreak: 125 cases of foodborne salmonellosis resulting from cross-contaminated food items served at a picnic and a smorgasbord.

One hundred and twenty-five of 173 people who ate at a picnic and/or a smorgasbord prepared by a bar-restaurant in a Midwestern town in September 1973 developed diarrhea, abdominal cramps, and other symptoms 23 hours (median time) later. Eleven were hospitalized. Stool cultures from 18 ill individuals grew Salmonella infantis, Salmonella agona, and Salmonella schwarzengrund. Stool cultures from 5 of 8 restaurant employees grew S. infantis or S. agona. Cultures of remaining foods and food-contact surfaces were negative. Food-specific attack rates, based on interviews with 121 eaters, implicated potato salad and chicken dressing as vehicles of transmission, both likely contaminated when prepared in pans that shortly before contained uncooked, chicken pieces suspected to have harbored salmonellae. Chickens were eventually traced to 3 farms where feed samples were found to contain Salmonella typhimurium and Salmonella cubana, raising the possibility that other feed samples may have contained the serotypes responsible for the outbreak. The main control measure was temporarily closing the food service, which was to have catered a large church picnic the next day. The outbreak had an economic impact estimated at $28,733.

Adult↗

PubMed1997

An outbreak of vancomycin-resistant Enterococcus faecium in liver transplant recipients.

Vancomycin-resistant Enterococcus faecium (VREF) has become a significant nosocomial pathogen for immunosuppressed patients. During a 5-month period in 1993, 8 cases of invasive infection with VREF (7 with bacteremia) were identified in liver transplant recipients, half of whom were adults. Epidemiology and microbiology studies were designed to identify the source and to determine the risk factors for this infection. Overall mortality was 50% (3 adults and 1 child). Mortality in bacteremic patients was 57%. A case-control study showed that cases were more likely to have been treated with a third-generation cephalosporin or vancomycin and to have undergone more than four biliary tract procedures. Environmental surveillance cultures yielded only one VREF isolate from a rectal temperature probe, but this device was used in only 2 of the cases. Cultures from all surgery and radiology suites were negative. All VREF isolates were genotyped by contour-clamped homogenous electric field electrophoresis of chromosomal DNA restriction fragments. These studies showed that a single clone was responsible for the outbreak, although other clones could be detected in the hospital. After implementing strict contact isolation on the liver transplant unit, only 1 additional patient with VREF was identified during this outbreak. In conclusion, it was found that antibiotic use and biliary tract manipulation were risk factors for developing invasive infections with VREF after liver transplantation. Optimal treatment is still unclear but most likely includes a combination of two or more antibiotics. Prompt institution of infection control measures can preclude rapid spread of this nosocomial pathogen.

Adolescent↗

PubMed2000

Outbreak of methicillin-resistant Staphylococcus aureus with reduced susceptibility to glycopeptides in a Parisian hospital.

Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased glycopeptide susceptibility isolated from November 1998 to March 1999 from 39 patients (17 infected and 22 colonized patients) in nine wards of the Broussais Hospital, Paris, France. Reduced glycopeptide susceptibility was readily detected on brain heart infusion (BHI) agar containing 6 microg of teicoplanin per ml and on gradient plates, but not by the standard disk diffusion method. The MICs of vancomycin and teicoplanin, determined on BHI agar, were 4 and 8 to 32 microg/ml, respectively (standard antibiotic dilution), and 4 to 8 and 8 to 32 microg/ml, respectively (E-test). All strains were resistant to macrolides, aminoglycosides, tetracycline, rifampin, sulfonamides, and pefloxacin, showed reduced susceptibility to fusidic acid and fosfomycin, and were susceptible to trimethoprim and chloramphenicol. Pulsed-field gel electrophoresis and lysotyping revealed that a multidrug-resistant MRSA clone with decreased susceptibility to glycopeptides has been discretely endemic since at least 1996 in our institution, where it was responsible for an outbreak in November and December 1998.

Anti-Bacterial Agents↗

PubMed2007

A novel two-component signaling system that activates transcription of an enterohemorrhagic Escherichia coli effector involved in remodeling of host actin.

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is responsible for worldwide outbreaks of bloody diarrhea, hemorrhagic colitis, and life-threatening hemolytic uremic syndrome. After colonizing the large intestine, EHEC forms attaching and effacing (AE) lesions on intestinal epithelial cells. These lesions cause destruction of the microvilli and elicit actin rearrangement to form pedestals that cup each bacterium individually. EHEC responds to a signal produced by the intestinal microbial flora, autoinducer-3 (AI-3), and the host hormones epinephrine and norepinephrine to activate transcription of the genes involved in AE lesion formation. These three signals, involved in interkingdom communication, are sensed by bacterial sensor kinases. Here we describe a novel two-component system, QseEF (quorum-sensing E. coli regulators E and F), which is part of the AI-3/epinephrine/norepinephrine signaling system. QseE is the sensor kinase and QseF the response regulator. The qseEF genes are cotranscribed, and transcription of qseEF is activated by epinephrine through the QseC sensor. A qseF mutant does not form AE lesions. QseF activates transcription of the gene encoding EspFu, an effector protein translocated to the host cell by the EHEC, which mimics a eukaryotic SH2/SH3 adapter protein to engender actin polymerization during pedestal formation. Expression of the espFu gene from a plasmid restored AE lesion formation to the qseF mutant, suggesting that lack of espFu expression in this mutant was responsible for the loss of pedestal formation. These findings suggest the QseEF is a two-component system involved in the regulation of AE lesion formation by EHEC.

Actins↗

PubMed1987

Control of a Serratia marcescens outbreak in a maternity hospital.

During the period between October 1984 and January 1985, an outbreak of Serratia marcescens took place in the Serlin Maternity Hospital in Tel-Aviv. Four major and six minor infections were noted in newborn and preterm infants. An additional group of 24 neonates were asymptomatic carriers of S. marcescens. Extensive control measures were undertaken, including closing the SCBU to further admissions and the opening of a new SCBU. Other measures included maintaining babies in cohort groups, strict handwashing, and use of gloves and gowns. There was also intensified encouragement of breast feeding and thorough cleansing and disinfection of the SCBU and nurseries. After 3 months, the outbreak was controlled. No identified source for the outbreak was detected. We feel that the extensive measures employed were responsible for controlling the outbreak within a relatively short time.

Bacteriological Techniques↗

PubMed1994

Management and control of a large outbreak of diarrhoea due to Clostridium difficile.

In the six-month period 1 November 1991 to 1 May 1992 175 patients developed diarrhoea due to Clostridium difficile in three hospitals in Manchester, UK. Most patients (90%) were over 60 years old and had been admitted to acute geriatric or medical wards with other illnesses. Infection is thought to have contributed to 17 deaths. Twenty-two patients relapsed clinically after antibiotic treatment. The outbreak began in one ward and affected 15 patients and two nurses. During the following months cases occurred on 34 wards. The pattern of spread suggested that a ward index case was followed by several secondary cases. Pyrolysis mass spectrometry showed that 79% of isolates of C. difficile belong to a single cluster and this putative outbreak strain also extensively colonizes the hospital environment. It was also responsible for a smaller outbreak in 1991 and many 'sporadic' cases in our hospitals before then. An outbreak control team was convened at an early stage and expert opinion co-opted. Infection control measures included: intensive education of staff; increased vigilance; strict enteric precautions; cohort nursing in a designated ward; rigorous cleaning procedures including emptying and 'deep' cleaning of wards where several cases had occurred; restriction of staff and patient movement; and restriction of antibiotic use. Subsequent to these measures there has been a substantial and sustained decrease in the number of new cases.

Aged↗

PubMed1999

Risk factors for an outbreak of multi-drug-resistant Acinetobacter nosocomial pneumonia among intubated patients.

INTRODUCTION: Acinetobacter baumanii is a Gram-negative coccobacillus that is normally a commensal pathogen but can be a nosocomial pathogen. An epidemiologic study was performed to investigate an outbreak of A baumanii that occurred in our medical intensive care unit (MICU) from March to September 1995. METHODS: A case-control study was performed by retrospective chart review, comparing case patients to randomly selected patients who were mechanically ventilated in the MICU for at least 1 week during the outbreak. A case patient was defined as any patient with an Acinetobacter infection in which the epidemic strain was considered to be a pathogen. The epidemic strain was defined by its antibiogram. Case patients and control patients were compared for age, gender, underlying disease, acute physiology and chronic health evaluation III score, length of MICU stay, prior antibiotic use, presence of fever, sepsis, type of pulmonary infiltrate, and outcome. Environmental and hand-washing studies also were performed during the period of the outbreak. Molecular typing was performed on available bloodstream isolates. RESULTS: There were 15 cases of A baumanii nosocomial pneumonia. Fifty percent were bacteremic; one chart was unavailable for review. Twenty-nine patients were identified as control patients. The mean age for case patients was 50 (range, 21 to 84). The mean duration of time from admission to the ICU to infection was 12.8 days (range, 4 to 40). Sepsis developed in 35% of the case patients. Forty-three percent of the case patients died during their hospitalization, with two of those deaths attributed to Acinetobacter infection. Univariate analysis showed that prior use of ceftazidime was associated with infection with Acinetobacter (11/14 case patients compared to 11/29 control patients; p < 0.01). Pulsed-field gel electrophoresis revealed two strains to be responsible for the outbreak. Hand washing was performed before patient contact by only 10% of health-care workers, and only 32% washed their hands after patient contact. CONCLUSION: The use of ceftazidime was associated with an increased risk of nosocomial pneumonia with resistant strains of Acinetobacter. Health-care workers need to improve compliance with hand-washing recommendations.

Acinetobacter Infections↗

PubMed1996

Epidemiology and control of acute respiratory diseases with emphasis on group A beta-hemolytic streptococcus: a decade of U.S. Army experience.

OBJECTIVE: To summarize the experiences of the U.S. Army regarding prevention and control, and frequencies, rates, trends, and determinants of febrile acute respiratory diseases (ARDs), particularly Group A beta-hemolytic streptococcus (GABHS). METHODOLOGY: Since 1966, the U.S. Army has conducted routine surveillance of ARDs among basic trainees. Since 1985, all trainees with fever and respiratory tract symptoms have been cultured for GABHS: Field investigations were conducted when outbreaks of acute respiratory or GABHS-associated illnesses were detected. Mass plus tandem benzathine penicillin prophylaxis were used to interdict and control training center GABHS outbreaks. RESULTS: During the period 1985 to 1994, there were 65,184 hospitalizations for acute febrile respiratory illnesses among Army trainees. The crude hospitalization rate was 0.45 per 100 trainees per week. The rate consistently declined over the period. Incremental declines were temporally associated with increased use of adenovirus immunizations and broader use of benzathine penicillin prophylaxis. During the period, 10,789 of 59,818 (18%) pharyngeal cultures were positive for GABHS: GABHS outbreaks were associated with diverse clinical manifestations including streptococcal toxic shock, acute rheumatic fever, and pneumonia. The emergence of mucoid colony morphology in clinical isolates was a consistent indicator of circulating virulent strains with epidemic potential. Outbreak-associated M types were M1, M3, M5, and M18. In response to six GABHS outbreaks, mass plus tandem benzathine penicillin chemoprophylaxis produced rapid and sustained GABHS control. ARD and GABHS recovery rates were lowest when benzathine penicillin prophylaxis was widely used. CONCLUSIONS: ARD rates among Army trainees have consistently declined to unprecedented levels. GABHS has reemerged as an important threat to military trainees. Benzathine penicillin chemoprophylaxis is safe and effective for interdicting and preventing GABHS outbreaks in closed, healthy young adult populations.

Chlamydophila pneumoniae↗

PubMed1995

[Outbreak of infections of Klebsiella pneumoniae with extended spectrum beta-lactamase in a hospital unit with a long and medium stay].

Fourteen extended-spectrum beta-lactamase (ES beta la) Klebsiella pneumoniae strains were isolated from 14 inpatients between February 1993 and February 1994, in a medium- and long-stay neurological unit. For this reason an epidemiological study was begun, based on strain typing and examination of patient files. Strain typing was carried out by two methods (i) the analysis of antibiotic resistance, showing 7 different antibiotypes among the 14 strains studied, (ii) the analysis of esterase and dehydrogenase electrophoretic polymorphism in polyacrylamide-agarose gel. The method was checked by analysing 11 Klebsiella pneumoniae strains with wild phenotype for beta-lactam antibiotics, which were isolated during the same period in the same unit. Simultaneously 6 other strains isolated during the same period in some other units of the hospital were analysed. Nine electrophoretic types were found among the 31 strains (wild and ES beta las). The analysis of the results showed that 8 isolates of the group of 14 ES beta las had the same antibiotype and electrophoretic type. This demonstrates that one epidemic strain was responsible for two outbreaks, the first one in April and the second one in August-September. A case control investigation was carried out to define the risk factors of infection. Files were examined for the 14 infected inpatients and for 20 control inpatients from the same unit during the same period. Statistical analysis was performed with Epi Info software 5 (CDC Atlanta). Length of stay, dependence and malnutrition levels, and urinary sphincter disfunction were the most significant risk factors.

Anti-Bacterial Agents↗

PubMed2006

Cholera in endemic districts in Uganda during El Niño rains: 2002-2003.

BACKGROUND: El Niño phenomenon causing increased rainfall and flooding has been linked to flare ups and emergence of several disease outbreaks including cholera. The latter has been reported in many districts in Uganda in recent years. Therefore an understanding of factors influencing its pattern of occurrence is needed for effective control. OBJECTIVES: To determine cholera disease status during six months of El Niño rains and assess serotypes and antibiotic sensitivity of isolates. METHODS: A prospective study was conducted in five cholera "endemic districts" in Uganda. RESULTS: Cholera outbreaks occurred in all the study districts coincident with the onset of the El Niño rains. There were 924 cholera suspect cases reported with 95 fatalities (case fatality rate 10.3%). A total of 388 clinical specimens were analyzed by culture and of these, 168 were positive for V. cholerae. Biochemical and serological analysis identified the isolates as V. cholerae O1, biotype EL Tor serotype Ogawa. Antibiotic sensitivity revealed that isolates were 100% sensitive to ciprofloxacin, tetracycline and erythromycin, whereas sensitivity was variable for other tested antibiotics. Unlike Kampala, where the disease was contained within three months, persistence occurred in other districts only dying out with end of El Niño rains, suggesting differences in disease control. CONCLUSION: These results show that El Niño rains cause increase in the number of cholera cases in Uganda, calling for preparedness and a need to emulate Kampala response incase of outbreaks in other districts.

Cause of Death↗

PubMed2001

Sabin monovalent oral polio vaccines: review of past experiences and their potential use after polio eradication.

After global eradication of polio is achieved, there will be a need for stockpiles of vaccine to combat potential outbreaks of poliomyelitis caused by (1) unforeseen release of polioviruses, (2) continued circulation of vaccine-derived strains, or (3) prolonged replication of polioviruses in immunodeficient persons. We conducted a review of the literature to document the immunogenicity and safety of monovalent Sabin vaccines, considered ideal candidates for these situations. The National Library of Medicine archives were searched for the keywords "polio," "monovalent," and "vaccine." Seroconversion rates for monovalent Sabin type 1 ranged from 53% to 100% (median, 95%); for type 2, 77%-100% (median, 93%); and for type 3, 52%-100% (median, 85%). The risk of vaccine-associated poliomyelitis per million persons vaccinated ranged from.05 to 0.99 (type 1), 0-0.65 (type 2), and 1.18-8.91 (type 3). Single-dose monovalent Sabin vaccines are highly immunogenic and safe and should be considered for stockpiles of vaccine to provide an effective response to potential outbreaks of poliomyelitis in the post-eradication period.

Antibodies, Viral↗

PubMed1992

[Hospital personnel who are nasal carriers of methicillin-resistant Staphylococcus aureus. Usefulness of treatment with mupirocin].

BACKGROUND: The evaluation of health care workers role in methicillin-resistant Staphylococcus aureus outbreaks and the efficacy of mupirocin as a topical agent for nasal carriers. METHOD: Microbiologic study of nasal microflora of 1547 health care workers from the San Carlos University Hospital and 108 health care workers from related hospitals while an outbreak of methicillin-resistant Staphylococcus aureus nosocomial infections is in progress at San Carlos University Hospital. Assessment of the efficacy of mupirocin nasal ointment for nasal carriers using microbiologic controls of nasal and pharyngeal swabs at the end of treatment and two weeks after. RESULTS: In San Carlos University Hospital a total of 53 health care workers with nasal carriage of methicillin-resistant Staphylococcus aureus were found. That figure represents a 3.4% of all health care workers studied and also a 15.4% of methicillin-resistance among all S. aureus isolated. Among health care workers from related hospitals, only one nasal carrier was found. Forty-seven of all 53 methicillin-resistant Staphylococcus aureus isolated from San Carlos University Hospital health care workers and the strain isolated from the related hospitals health care worker were similar to the epidemic strain responsible for the outbreak. Mupirocin, as nasal ointment, was useful in eliminating nasal colonization in all cases. CONCLUSIONS: When a nosocomial outbreak of methicillin-resistant Staphylococcus aureus infections is detected, health care workers are one of the most important reservoirs. Topical treatment with mupirocin (nasal ointment) is useful for eliminating the nasal carrier status.

Administration, Intranasal↗

PubMed1990

An outbreak of granulomatous vulvitis in feedlot heifers.

An unusual form of vulvitis occurred in outbreak form affecting at least 18 of a group of 35 to 40 heifers soon after their introduction to a feedlot in the western Transvaal area of the Republic of South Africa. Initially, affected animals showed a knob-like swelling of the ventral commissure of the vulva. This grew in size up to approximately 6 cm in diameter and then appeared to burst open and give rise to a granulomatous lesion. Bovine herpesvirus type-1, Moraxella bovis, Mycoplasma bovigenitalium and Mycoplasma bovis were isolated from 2 affected heifers referred for diagnostic investigation. Mycoplasma canadense was isolated from one of the heifers. Attempts to reproduce the disease by transferring an excised portion of the lesion to unaffected animals, resulted only in lesions typical of uncomplicated infectious pustular vulvovaginitis. It is proposed that that multifactorial aetiology, including synergistic pathogenic action between the organisms isolated, was responsible for this outbreak. Administration of oxytetracycline to affected animals was followed by prompt resolution of symptoms. No further outbreaks have been reported.

Animals↗

PubMed2003

Characteristics of individuals with male-to-male and heterosexually acquired infectious syphilis during an outbreak in Calgary, Alberta, Canada.

BACKGROUND: Eliminating syphilis is important not only to prevent the sequelae of infection but also to control the spread of HIV. Current prevention and control efforts in Canada have been ineffective in eliminating this disease. GOAL: The goal of the study was to determine the characteristics of individuals with infectious syphilis due to male-to-male and heterosexual contact, diagnosed during an outbreak in Calgary, Alberta, Canada. STUDY DESIGN: This was a prospective study of individuals with infectious syphilis diagnosed at the STD clinic in Calgary between January 2000 and April 2002. RESULTS: The outbreak reported here (September 2000 to April 2002) involves 32 cases of infectious syphilis, corresponding to rates of 0.9/100,000 population during 2000 and 1.8/100,000 population during 2001. Between September 2000 and June 2001, the cases diagnosed were among men who have sex with men (MSM); between May 2001 and April 2002, they were due to locally acquired infections among heterosexuals, including one case of congenital syphilis. Compared to the heterosexuals, MSM tended to be older, be coinfected with HIV, and report excessive alcohol use (versus injection drug use) and had infectious syphilis diagnosed earlier. MSM used the Internet and bars or bathhouses to initiate sexual contact, whereas heterosexually acquired infections were largely among sex workers and their clients. Contact tracing was more successful among the heterosexuals than among MSM. The public health staff at the STD clinic initiated a series of multifaceted interventions in response to the outbreak. These interventions were moderately successful, as measured by the increased numbers of individuals seeking counseling and testing services at the clinic. CONCLUSION: The results highlight key differences in the risk factor-specific characteristics of the outbreak that should be taken into account when designing prevention and control strategies.

Adult↗

PubMedDate not supplied

Clonal expansion of sequence type (ST-)5 and emergence of ST-7 in serogroup A meningococci, Africa.

One hundred four serogroup A meningococci in our collection, isolated in Africa from 1988 to 1999, were characterized by multilocus sequence typing (MLST). Our results and data from the Internet indicate that sequence type 5 (ST-5) strains were responsible for most of African outbreaks and sporadic cases during this period. In 1995, a new clone, characterized by ST-7 sequence, emerged and was responsible for severe outbreaks in Chad (1998) and Sudan (1999). MLST and epidemiologic data indicate that ST-5 and ST-7 represent two virulent clones. These two STs, which belong to subgroup III, differ only in the pgm locus: allele pgm3 is characteristic for ST-5 and allele pgm19 for ST-7. Subgroup III strains were responsible for two pandemics in the 1960s and 1980s. Our data show that the third subgroup III pandemic has now reached Africa.

Africa↗