Comparison of DNA fingerprinting methods for use in investigation of type E botulism outbreaks in the Canadian Arctic

Pulsed-field gel electrophoresis (PFGE), randomly amplified polymorphic DNA (RAPD) analysis, and automated ribotyping were compared for epidemiological typing of Clostridium botulinum type E using clinical and food isolates associated with four botulism outbreaks occurring in the Canadian Arctic. All type E strains previously untypeable by PFGE, even with the use of a formaldehyde fixation step, could be typed by the addition of 50 microM thiourea to the electrophoresis running buffer. Digestion with SmaI or XhoI followed by PFGE was used to link food and clinical isolates from four different type E botulism outbreaks and differentiate them from among 39 group II strains. Strain differentiation was unsuccessful with the automated ribotyping system, producing a single characteristic EcoRI fingerprint common to all group II strains. RAPD analysis of C. botulinum group II strains was not consistently reproducible with primer OPJ-6 or OPJ-13, apparently discriminating between epidemiologically related strains. A modified PFGE protocol was judged to be the most useful method for typing epidemiologically related C. botulinum type E strains, based on its ability to type all strains reproducibly and with an adequate level of discrimination.

REPEATED LOW-LEVEL EXPOSURE OF THE ROUND GOBY (NEOGOBIUS MELANOSTOMAS) TO CLOSTRIDIUM BOTULINUM TYPE E NEUROTOXIN

In a 4-mo study (June 2004-September 2004), round gobies (Neogobius melanostomas) were dosed orally every 72 hr for up to 21 days with Clostridium botulinum neurotoxin type E (BoNT/E) at one of four doses: 0, 50, 250, and 500 mouse lethal doses (MLD). Fish were observed for changes in pigmentation and behavior for the duration of the experiment. Mortality was observed with all treatments, with the exception of the 0 MLD control. Clinical signs observed were consistent with prior research and appeared to occur in a threshold manner. The mean times to death and percent mortalities were dose dependent. Hazard ratios were determined to have a significant positive (parameter estimate = 0.03) linear relationship with dose. The hazard ratio showed that per one unit dose increase, the instantaneous probability of a fish dying increased 1.02%. Postmortem analysis of experimental fish demonstrated that 11% (3/27) of fish contained detectable BoNT/E in their visceral fraction. The other 89% tested negative for BoNT/E, despite the fact that all fish died as a result of BoNT/E exposure. Therefore, botulism should not necessarily be ruled out as the cause of a fish kill, even if the fish test negative for BoNT/E.

Adult botulism type F in the United States, 1981-2002

BACKGROUND

Clostridium botulinum neurotoxin types A, B, and E cause most cases of the paralytic disease botulism. Little is known about the epidemiology, clinical features, or microbiology of botulism type F.

METHODS

Cases of adult type F botulism were identified by review of data collected by CDC's National Botulism Surveillance System between 1981 and 2002. A case was either an individual whose serum or stool demonstrated type F toxin or whose stool culture yielded an organism producing toxin type F. A detailed review of cases' medical charts and laboratory data from CDC and local health departments was performed.

RESULTS

Between 1981 and 2002, 1,269 cases of botulism among adults and infants were reported to CDC; 13 (1%) were adult type F. The median age of type F cases was 54 years; 7 (54%) were female. None were part of outbreaks. A toxigenic Clostridium baratii was identified in 9 (69%) of 13 cases. Among 11 cases for which clinical data were available, all required mechanical ventilation for a median duration of 17 days (range, 10 to 84); 8 (73%) were intubated within 24 hours of symptom onset. All patients had nearly complete or complete quadriplegia at the nadir of neurologic dysfunction, which occurred on average on day 5. On average by day 8, improvement in neuromuscular function was noted. The median duration of acute hospitalization was 31 days (range, 20 to 60). No deaths were reported. In only one case was a possible foodborne etiology identified.

CONCLUSIONS

Toxigenic C baratii are the sole documented causes of type F botulism in the United States since 1981. These cases are characterized by a fulminant course with rapid progression to respiratory failure and paralysis, making early recognition and intervention critical to appropriate management.

Characterization of the neurotoxin produced by isolates associated with avian botulism

Several varieties of birds are affected by type C botulism. We conducted neutralization tests of culture supernatants of isolates from cases of avian botulism. Whereas the toxin produced by isolates derived from mammalian botulism was neutralized only with type C antitoxin, the toxins of all isolates related to avian botulism were neutralized with both type C and D antitoxins. An analysis of nucleotide sequences with several strains revealed that the neurotoxin gene in the isolates from avian botulism comprises two thirds of the type C neurotoxin gene and one third of the type D neurotoxin gene. This indicates that the neurotoxin of avian isolates is a mosaic of type C and D neurotoxins. We prepared three sets of primers to differentiate the gene for the mosaic form from the conserved genes of type C and D neurotoxins. The results of polymerase chain reaction with these primers indicated that all avian botulism-related isolates and specimens possess the gene for the mosaic form of the neurotoxin. The toxins purified from avian and mammalian isolates exhibited the same degree of lethality in mice, but the former showed greater toxicity to chickens than the latter. These results indicate that the mosaic neurotoxin is probably a pathogenic agent causing some forms of avian botulism.

Infant botulism due to consumption of contaminated commercially prepared honey. First report from the Arabian Gulf States

OBJECTIVE

To report the first case of infant botulism in Arabian Gulf States.

CLINICAL PRESENTATION AND INTERVENTION

A 6-week-old infant, presenting with signs of sepsis, was intubated and ventilated due to progressive weakness. Infant botulism was suspected with acute flaccid paralysis and a history of honey consumption. An electromyogram showed decreased amplitude of compound muscle action potential in all motor nerves, preserved sensory responses; the motor terminal latencies and motor conduction velocities were normal. Blood, stool and honey samples were sent for culture. Stool and honey cultures showed two identical strains of Clostridium botulinum.

CONCLUSION

This case shows that the infant botulism occurred from the ingested contaminated honey. Hence vigilance should be maintained when a baby is fed honey and shows signs of progressive weakness because the disease can quickly progress to respiratory failure.

Botulism: the challenge of diagnosis and treatment

Botulism is a rare paralytic disease caused by a neurotoxin produced from the spore-forming bacterium Clostridium botulinum and in rare cases Clostridium butyricum and Clostridium baratii. Botulism has 4 naturally occurring syndromes: foodborne, wound, infant botulism, and adult intestinal toxemia. Inhalational botulism could result from aerosolization of botulinum toxin, and iatrogenic botulism can result from injection of toxin. All of these produce the same clinical syndrome of symmetrical cranial nerve palsies followed by descending, symmetric flaccid paralysis of voluntary muscles, which may progress to respiratory compromise and death. Treatment includes meticulous intensive care that includes mechanical ventilation, when necessary, and administration of antitoxin.

Improvement in laboratory diagnosis of wound botulism and tetanus among injecting illicit-drug users by use of real-time PCR assays for neurotoxin gene fragments

An upsurge in wound infections due to Clostridium botulinum and Clostridium tetani among users of illegal injected drugs (IDUs) occurred in the United Kingdom during 2003 and 2004. A real-time PCR assay was developed to detect a fragment of the neurotoxin gene of C. tetani (TeNT) and was used in conjunction with previously described assays for C. botulinum neurotoxin types A, B, and E (BoNTA, -B, and -E). The assays were sensitive, specific, rapid to perform, and applicable to investigating infections among IDUs using DNA extracted directly from wound tissue, as well as bacteria growing among mixed microflora in enrichment cultures and in pure culture on solid media. A combination of bioassay and PCR test results confirmed the clinical diagnosis in 10 of 25 cases of suspected botulism and two of five suspected cases of tetanus among IDUs. The PCR assays were in almost complete agreement with the conventional bioassays when considering results from different samples collected from the same patient. The replacement of bioassays by real-time PCR for the isolation and identification of both C. botulinum and C. tetani demonstrates a sensitivity and specificity similar to those of conventional approaches. However, the real-time PCR assays substantially improves the diagnostic process in terms of the speed of results and by the replacement of experimental animals. Recommendations are given for an improved strategy for the laboratory investigation of suspected wound botulism and tetanus among IDUs.

Genotyping Clostridium botulinum toxinotype A isolates from patients using amplified rDNA restriction analysis

In this study, the application of amplified rDNA restriction analysis (ARDRA) for characterizing Clostridium botulinum toxinotype A strains isolated from individuals with botulism was evaluated. Ten restriction enzymes were tested for their suitability in ARDRA as a typing method and HhaI was selected for the best outcome. Analysis of HhaI restriction profiles of the amplified products divided C. botulinum isolates into three clusters. Non-toxigenic Clostridium sporogenes strains showed an ARDRA restriction pattern that was distinct from those observed for C. botulinum. The successful use of ARDRA for subdivision of C. botulinum in this study confirmed that this technique is a powerful method for typing of C. botulinum toxinotype A clonal diversity. In addition, it is rapid, sensitive and simple.

First case of infant botulism caused by Clostridium baratii type F in California

In late 2003 a severely hypotonic neonate, just 38 h old at onset of illness, was found to have infant botulism caused by neurotoxigenic Clostridium baratii type F. Environmental investigations failed to identify a source of this strain. This is the youngest patient reported to have infant botulism and the fifth instance of infant botulism caused by C. baratii type F.

Distribution of botulinum toxin-producing clostridia in soils of Argentina

We studied the presence of botulinum toxin-producing clostridia in 2,009 soil samples from five geographical regions of Argentina. The prevalence was 23.5%, and the distribution was not homogeneous among the regions. We observed a great multiplicity of serological types and a higher prevalence in nonvirgin soils than in virgin soils.

Histopathology and immunohistochemistry in the diagnosis of bioterrorism agents

From October to November 2001, the inhalational and cutaneous anthrax cases that occurred in the U.S. underscored the importance of recognizing the clinical and pathological features of infectious agents that can be used in acts of terrorism. Early confirmation of bio-terrorist acts can only be performed by making organism-specific diagnosis of cases with clinical and pathologic syndromes that could be caused by possible bioterrorism weapons. Recognition and diagnosis of these cases is central to establish adequate responses. This review will examine the events that occurred during the anthrax bio-terrorist attack with specific emphasis on the role of pathology and immunohistochemistry and will describe the histopathologic features of category A bioterrorism agents (anthrax, plague, tularemia, botulism, smallpox, and viral hemorrhagic fevers).

Development and application of Real-Time PCR assays to detect fragments of the Clostridium botulinum types A, B, and E neurotoxin genes for investigation of human foodborne and infant botulism

Real-time PCR assays for detection of Clostridium botulinum neurotoxin (BoNT) gene fragments specific to BoNTA, B, and E were developed as alternatives to the mouse bioassay. The expected specificities of the PCR assays were demonstrated by in silico analysis as well as empirical testing of target DNA extracted from 83 pure cultures of C. botulinum, and 44 bacteria from other species. The sensitivities of the assays were found to be equivalent to 16, 10, and 141 genomes for BoNT A, B, and E, respectively. The assays were shown to be applicable to both purified DNA, as well as crude DNA extracted from cultures and enrichment broths. The assays were evaluated using DNA extracted directly from clinical and food specimens as well as from inoculated broths using material collected from seven confirmed and one suspected case of botulism. The appropriate BoNT genes were detected in material from seven of the eight cases of botulism and provided a supportive diagnosis faster than the conventional bioassay. These assays have already proven useful for pubic health microbiological investigation of suspected cases of human botulism by substantially improving the diagnostic process.

Proteolytic Clostridium botulinum type B in the gastric content of a patient with type E botulism due to whitefish eggs

Whitefish eggs were confirmed by pulsed-field gel electrophoresis to cause type E foodborne botulism in a 54-year-old patient in Finland. Botulinum neurotoxin and/or nonproteolytic Clostridium botulinum type E organisms were detected in fecal and gastric samples from the patient and in suspected whitefish eggs. Apart from C. botulinum type E, proteolytic type B organisms were detected in the patient's gastric content. This was considered to be insignificant with respect to the clinical disease, suggesting botulinal spores to be occasionally present in the human gastrointestinal tract without any apparent clinical significance. This is the first domestic case of foodborne botulism in Finland.

A case of infant botulism with a possible link to infant formula milk powder: evidence for the presence of more than one strain of Clostridium botulinum in clinical specimens and food

Infant botulism was confirmed in a 5-month-old female by both isolation of Clostridium botulinum type B and by detection of type B botulinum neurotoxin in rectal washout and faeces. DNA fingerprinting of nine isolates from faeces yielded two different amplified-fragment length polymorphism (AFLP) patterns. C. botulinum was isolated from two of 14 food and drink items from the patient's home: C. botulinum type A was recovered from an opened container of dried rice pudding and C. botulinum type B from opened infant formula milk powder. Ten C. botulinum type B isolates from the opened infant formula yielded four AFLP patterns, two of which were indistinguishable from the clinical isolates. Fifteen unopened foods were tested and C. botulinum type B of a unique AFLP pattern was recovered from one unopened infant formula of the same batch as the opened container. It is suggested that multiple C. botulinum were present in both food and the intestine during infant botulism.

Elimination of botulinum neurotoxin (BoNT) type B from drinking water by small-scale (personal-use) water purification devices and detection of BoNT in water samples

Seven small-scale drinking water purification devices were evaluated for their capacity to eliminate botulinum neurotoxin (BoNT) type B from drinking water. Influent water inoculated with toxic Clostridium botulinum cultures and effluent purified water samples were tested for the presence of BoNT by using a standard mouse bioassay and two commercial rapid enzyme immunoassays (EIAs). The water purification devices based on filtration through ceramic or membrane filters with a pore size of 0.2 to 0.4 microm or irradiation from a low-pressure UV-lamp (254 nm) failed to remove BoNT from raw water (reduction of < 0.1 log10 units). A single device based on reverse osmosis was capable of removing the BoNT to a level below the detection limit of the mouse bioassay (reduction of > 2.3 log10 units). The rapid EIAs intended for the detection of BoNT from various types of samples failed to detect BoNT from aqueous samples containing an estimated concentration of BoNT of 396,000 ng/liter.

Detection of Clostridium botulinum type C cells in the gastrointestinal tracts of Mozambique Tilapia (Oreochromis mossambicus) by polymerase chain reaction

We established a method of directly detecting Clostridium botulinum type C cells, while minimizing spore detection, in the intestinal contents of Mozambique tilapia (Oreochromis mossambicus). This technique involved extraction of predominantly cellular DNA from tilapia intestinal tracts and used a polymerase chain reaction assay to detect presence of type C1 toxin gene. We consistently detected C. botulinum type C cells in tilapia gastrointestinal contents at a level of 7.5 x 104 cells per 0.25 g material or 1.9 x 103 cells. This technique is useful for determining prevalence of the potentially active organisms within a given population of fish and may be adapted to other types of C. botulinum and vertebrate populations as well.

Characterization of Clostridium botulinum strains associated with an infant botulism case in the United Kingdom

The sixth case of infant botulism in the United Kingdom was reported in 2001. The case was caused by a type B strain of Clostridium botulinum. Strains of C. botulinum were isolated from the baby's feces and from foodstuffs in the household in an attempt to document transmission. The aims of this study were to characterize the strains of C. botulinum associated with the botulism case. This was performed using a variety of techniques, including C. botulinum culture phenotypic properties, neurotoxin characterization, and pulsed-field gel electrophoresis (PFGE) banding patterns. Cultures associated with this case as well as isolates from stored and historical samples were analyzed and compared. C. botulinum type B PFGE patterns from the infant and from an opened container of infant formula were indistinguishable, while the PFGE profile of a strain presumably isolated from an unopened archival container was unique. The results suggest that the unopened brand of formula was not the source for transmission of spores to the infant and that the strain was distinct from previous botulism cases in the United Kingdom. Since environmental testing was not performed, it is not possible to deduce other sources of transmission.

Prevalence of neurotoxic Clostridium botulinum type C in the gastrointestinal tracts of tilapia (Oreochromis mossambicus) in the Salton Sea

Tilapia (Oreochromis mossambicus) have been implicated as the source of type C toxin in avian botulism outbreaks in pelicans (Pelecanus erythrorhynchos, Pelecanus occidentalis californicus) at the Salton Sea in southern California (USA). We collected sick, dead, and healthy fish from various sites throughout the Sea during the summers of 1999 through 2001 and tested them for the presence of Clostridium botulinum type C cells by polymerase chain reaction targeting the C(1) neurotoxin gene. Four of 96 (4%), 57 of 664 (9%), and five of 355 (1%) tilapia tested were positive for C. botulinum type C toxin gene in 1999, 2000, and 2001, respectively. The total number of positive fish was significantly greater in 2000 than in 2001 (P<0.0001). No difference in numbers of positives was detected between sick and dead fish compared with live fish. In 2000, no significant relationships were revealed among the variables studied, such as location and date of collection.

Infant botulism acquired from household dust presenting as sudden infant death syndrome

Clostridium botulinum type B was detected by multiplex PCR in the intestinal contents of a suddenly deceased 11-week-old infant and in vacuum cleaner dust from the patient's household. C. botulinum was also isolated from the deceased infant's intestinal contents and from the household dust. The genetic similarity of the two isolates was demonstrated by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA analysis, thereby confirming that dust may act as a vehicle for infant botulism that results in sudden death.

Infant botulism, type F, presenting at 54 hours of life

We report a case of botulism in a 54-hour-old infant with rapidly progressive fulminant paralysis and rapid spontaneous recovery atypical for infant botulism. Clostridium baratii and type F botulinum neurotoxin were isolated from the patient's stool. This unique presentation with rapid recovery is consistent with pharmacokinetics of type F botulinum neurotoxin. Interestingly, a muscle biopsy also revealed pathologic changes early in the disease course. This article reports the youngest known case of infant botulism and only the third reported case of this disease caused by type F neurotoxin. Botulism should be considered in patients of any age with subacute or acute neuromuscular weakness.

[Botulism in Poland in 2003]

A total number of 78 foodborne botulism cases were registered in Poland in 2003, (incidence rate 0.20 per 100 000 population), in rural areas--46 cases (incidence 0.31) and in urban areas--32 cases (incidence 0.14). There were noted 48 sporadic cases, 8 outbreaks of two persons and 1 outbreak of three, four and five people. Meat dishes were the main vehicle of botulinum toxin, especially home made bottling jars prepared from pork meat (24.4% of cases). Two deaths from foodborne botulism were registered.

Dual toxin-producing strain of Clostridium botulinum type Bf isolated from a California patient with infant botulism

A retrospective study of Clostridium botulinum strains isolated from patients from California with infant botulism identified the fourth known C. botulinum strain that produces both type B and type F botulinum toxins. This unique strain represented 0.12% of the California infant botulism case isolates from 1976 to 2003. The relative concentrations of type B and F toxins produced were temperature dependent.

Considering the antimicrobial sensitivity of the intestinal botulism agent Clostridium butyricum when treating concomitant infections

In Italy, neurotoxigenic Clostridium butyricum has been reported as a new agent of intestinal toxemia botulism, and most of the cases have been associated with enterocolitis. Although infections concomitant with botulism must be treated with antibiotics, this can increase the severity of botulism. We discuss the sensitivity of this agent to certain antibiotics, compared to findings on the sensitivity of C. botulinum.