Toxigenicity Of Strains Research Articles

Detection of Enterotoxigenic Staphylococcus aureus in Patients with Gastroenteritis in Erbil/Iraq

Gastroenteritis is one of the words serious public health problem, and enterotoxigenic Staphylococcus aureusis one of the causes of gastroenteritis. The aim of this study was the molecular detection of enterotoxigenicgenes in Staphylococcus aureus, then detection the association of resistance patterns with the toxigenicityof strains. Microbiological analysis of fecal samples from patients with gastroenteritis was performed fordetection of S. aureus. The samples were cultured and identified by routine bacteriological methods andVITEK 2 system. Subsequently PCR amplification of enterotoxin genes (sea and seb) was carried outon all S. aureus strains. The results indicated that in total of 417 fecal samples taken from patients withacute gastroenteritis, 30 grew S. aureus (7.19%), and of 417 fecal samples 96 yielded bacterial pathogens(23.02%), S. aureus was the most common bacterial pathogen found in 30/96 cases (31.25%). In 30 isolatedof S. aureus, penicillin sensitive S. aureus were 2 (6.67%), methicillin sensitive S. aureus were 19 (63.33%),multidrug resistant S. aureus were 12 (40%), methicillin resistant S. aureus were 11 (36.67%), Extensivedrug resistance were 3 (10%), and none of them was pan drug resistant,and all isolates were sensitive tovancomycin. The PCR results showed that 7/30 (23.33%) of the S. aureus isolates possessed the sea gene,and 3/30 (10 %) had the seb gene. In total of 30 isolates Staphylococcal enterotoxin genes sea and seb weremore prevalent among methicillin resistant S. aureus were 6/11 (54.54%), 3/11 (27.27%) respectively, thenin multidrug resistant S. aureus which were 6/12 (50%), and 3/12 (25%) respectively, and in Extensivelydrug resistance S. aureus sea was1/3 (33.33%) and there is no seb genes, while in methicillin sensitive S.aureus sea was 1/19 (5.26%), and there is no seb genes, and there was no Staphylococcal enterotoxin genessea and seb in penicillin sensitive S. aureus. The result confirmed the involvement of enterotoxigenic S.aureus in the occurrence of gastroenteritis, and isolates with enterotoxin genes have a higher drug resistancerate.

Infection with enterotoxigenic Staphylococcus aureus as a concern in patients with gastroenteritis.

Intestinal overgrowth of Staphylococcus aureus may promote unpleasant disorders in the human intestinal tract. This study assessed the prevalence of enterotoxigenic multidrug-resistant S. aureus (MDR-SA) in patients with gastroenteritis. Microbiological analysis of 345 faecal samples from patients with gastroenteritis was performed to detect infection with S. aureus in the absence of common enteric pathogens. Methicillin-resistant S. aureus (MRSA) was characterised by the cefoxitin disk diffusion method. PCR amplification of enterotoxin genes (sea, seb, sec, sed and see) was carried out on all S. aureus strains, and association of resistance patterns with the toxigenicity of strains was determined statistically. Infection with S. aureus was detected in 64 samples (18.6%), of which 51 (79.7%) and 41 (64.1%) were determined as MRSA and MDR-SA, respectively. Resistance to six antibiotic classes was the most common MDR pattern (48.8%; 20/41). In total, 50% of the strains (32/64) carried the studied enterotoxin genes; the most common was sea (56.1%), followed by sec (4.9%) and see (4.9%). These genes were more prevalent among MDR-MRSA (58.8%) compared with methicillin-sensitive S. aureus (15.4%) strains. These results confirmed the involvement of enterotoxigenic MRSA in the occurrence of gastroenteritis.

Preventing the preventable through effective surveillance: the case of diphtheria in a rural district of Maharashtra, India

BackgroundEpidemic diphtheria is still poorly understood and continues to challenge both developing and developed countries. In the backdrop of poor immunization coverage, non-existent adult boosters, weak case based surveillance and persistence of multiple foci, there is a heightened risk of re-emergence of the disease in epidemic forms in India. Investigating each outbreak to understand the epidemiology of the disease and its current status in the country is therefore necessary. Dhule a predominantly tribal and rural district in Northern Maharashtra has consistently recorded low vaccination coverages alongside sporaidic cases of diphtheria over the last years.MethodsThis study reports the findings of an onsite survey conducted to assess a recent outbreak of diphtheria in Dhule district and the response mounted to it. Secondary data regarding outbreak detection and response were obtained from the district surveillance office. Clinical data were extracted from hospital records of eleven lab confirmed cases including one death case. Frequency distributions were calculated for each identified clinical and non- clinical variable using Microsoft™ Excel® 2010.ResultsOur findings suggest a shift in the median age of disease to adolescents (10-15 years) without gender differences. Two cases (18%) reported disease despite immunization. Clinical symptoms included cough (82%), fever (73%), and throat congestion (64%). About 64% and 36% of the 11 confirmed cases presented with a well defined pseudomembrane and a tonsillar patch respectively. Drug resistance was observed in all three culture positive cases. One death occurred despite the administration of Anti-Diphtheric Serum in a partially immunized case (CFR 9%). Genotyping and toxigenicity of strain was not possible due to specimen contamination during transport as testing facilities were unavailable in the district.ConclusionsThe outbreak raises several concerns regarding the epidemiology of diphtheria in Dhule. The reason for shift in the median age despite consistently poor immunization coverage (below 50%) remains unclear. Concomitant efforts should now focus on improving and monitoring primary immunization and booster coverages across all age groups. Gradually introducing adult immunization at ten year intervals may become necessary to prevent future vulnerabilities. Laboratory networks for genotyping and toxigenicity testing are urgently mandated at district level given the endemicity of the disease in the surrounding region and its recent introduction in remote Dhule. Contingency funds with pre- agreements to obtain ADS and DT/Td vaccines at short notice and developing standard case management protocols at district level are necessary. Monitoring the disease, emerging strains and mutations, alongside drug resistance through robust and effective surveillance is a pragmatic way forward.

Production of corynetoxins in vitro by Corynebacterium sp. isolated from annual ryegrass seedheads

Corynetoxin complex is the family of tunicamycin-like antibiotics isolated from annual ryegrass (Lolium rigidum) seedheads infected with a plant pathogenic Corynebacterium and identified as the causative toxins for annual ryegrass toxicity (ARGT) in Australia. Only trace amounts of corynetoxins have been reported to be produced in vitro. Enhanced in vitro production of corynetoxins by Corynebacterium sp. has now been demonstrated. The important conditions required were growth on an agar surface, absence of light, low incubation temperature and strain of the organism. Strains of the Corynebaterium sp. grown under conditions not supporting corynetoxin production failed to produce corynetoxins when subsequently grown under more favourable conditions. Even when maintained under the most favourable conditions, toxigenicity of strains declined on repeated subculturing. While levels of toxin typically produced in vitro were only about 5% of those found in infected ryegrass seedheads, they were high enough to be a useful source of corynetoxins for experimental purposes.