Emergence and clonal dissemination of Salmonella enterica serovar Enteritidis causing salmonellosis in Mauritius.

INTRODUCTION: For decades, Salmonella enterica serovar Enteritidis has been among the most prevalent serovars reported worldwide. However, it was rarely encountered in Mauritius until 2007; since then the number of non-typhoidal Salmonella serogroup O:9 (including serovar Enteritidis) increased. A study was conducted to investigate the genetic relatedness between S. Enteritidis isolates recovered in Mauritius from food and clinical specimens (stool, blood, and exudate). METHODOLOGY: Forty-seven isolates of S. Enteritidis obtained in 2009 from human stools, blood cultures and exudates, and from food specimens were characterized by antimicrobial susceptibility testing and Multiple-Locus Variable-number tandem repeat Analysis (MLVA). RESULTS: With the exception of a single isolate which demonstrated intermediate susceptibility to streptomycin, all isolates were pansusceptible to the 14 antimicrobials tested. Thirty seven out of the 47 isolates (78.7%) exhibited an indistinguishable MLVA profile which included isolates from ready-to-eat food products, chicken, and human clinical isolates from stool, blood and exudate. CONCLUSIONS: The presence of highly related strains in both humans and raw chicken, and the failure to isolate the serovar from other foods, suggests that poultry is the main reservoir of S. Enteritidis in Mauritius and that the majority of human cases are associated with chicken consumption which originated from one major producer. Stool isolates were indistinguishable or closely related to blood and exudate isolates, indicating that, besides gastroenteritis, the same strain caused invasive infections. Control of S.Enteritidis by poultry breeders would lower the financial burden associated with morbidity in humans caused by this organism in Mauritius.

Dissemination of clonal Salmonella enterica serovar Typhimurium isolates causing salmonellosis in Mauritius.

Salmonella enterica serotype Typhimurium is one of the leading causes of salmonellosis in Mauritius, where it has also been associated with outbreaks of foodborne illness. However, little is known about its molecular epidemiology in the country. This study was therefore undertaken to investigate the clonality and source of Salmonella Typhimurium in Mauritius by studying human, food, and poultry isolates by pulsed-field gel electrophoresis (PFGE) and antibiotic minimum inhibitory concentration determination. Forty-nine isolates collected between 2008 and 2011 were analyzed, including 25 stool isolates from foodborne illness outbreaks and sporadic gastroenteritis cases, four blood isolates, one postmortem colon isolate, 14 food isolates, and five poultry isolates. All isolates were pansusceptible to the 16 antibiotics tested, except for two isolates that were resistant to sulfamethoxazole and trimethoprim. Overall characterization of the isolates by PFGE digested with XbaI and BlnI resulted in eight different patterns. The largest of the clusters in the composite dataset consisted of 20 isolates, including two raw chicken isolates, four poultry isolates, and nine human stool isolates from two outbreaks. A second cluster consisted of 18 isolates, of which 12 originated from human blood and stool samples from both sporadic and outbreak cases. Six food isolates were also found in this cluster, including isolates from raw and grilled chicken, marlin mousse, and cooked pork. One poultry isolate had a closely related PFGE pattern. The results indicate that one clone of Salmonella Typhimurium found in poultry has been causing outbreaks of foodborne illness in Mauritius and another clone that has caused many cases of gastrointestinal illness and bacteremia in humans could also be linked to poultry. Thus, poultry appears to be a major reservoir for Salmonella Typhimurium in Mauritius. Initiating on-farm control strategies and measures against future dissemination may substantially reduce the number of cases of salmonellosis in the country.

An outbreak of Elizabethkingia meningoseptica neonatal meningitis in Mauritius.

INTRODUCTION: Elizabethkingia meningoseptica is a rare but well-recognised cause of neonatal meningitis. Reported outbreaks have involved very few cases. We describe the management and outcome of a relatively large outbreak of E.meningoseptica neonatal meningitis METHODOLOGY: From August 2002 to December 2003, eight cases of meningitis caused by E. meningoseptica occurred among babies admitted to the neonatal ward of Jawarhlal Nehru hospital, Mauritius. In all cases, the organism was isolated from the cerebrospinal fluid. Infection control measures were re-emphasized after each case and environmental swabs were cultured on several occasions.  RESULTS: The affected babies were aged 6 to 20 days (mean age of 10 days). Seven of the babies weighed < 2,500 g. All CSF isolates had the same antibiotic susceptibility pattern. Apart from one baby who died shortly after admission, all cases responded to treatment with intravenous piperacillin and oral rifampicin for three weeks. Hydrocephalus developed in two babies and was subsequently fatal in one case. At follow-up of the other cases, one baby had severe neurological sequelae but a full recovery was observed in the other four cases. The source of the outbreak could not be established conclusively.  CONCLUSIONS: The outcome was better than what has been reported in the medical literature. Prompt identification of the causative organism and initiation of appropriate antimicrobial therapy is essential. The combination of piperacillin and rifampicin should be considered an option for the treatment of E. meningoseptica neonatal meningitis if supported by properly performed antibiotic susceptibility test results. 

Reemergence of dengue in Mauritius.

Dengue reemerged in Mauritius in 2009 after an absence of >30 years, and >200 cases were confirmed serologically. Molecular studies showed that the outbreak was caused by dengue virus type 2. Phylogenetic analysis of the envelope gene identified 2 clades of the virus. No case of hemorrhagic fever was recorded.

Salmonella enterica serovar Typhimurium in Mauritius linked to consumption of marlin mousse.

We report the first outbreak of salmonellosis caused by consumption of contaminated marlin mousse. Between 29 October and 5 November 2008, at least 53 persons developed diarrheal illness, all with a history of eating marlin mousse. Salmonella spp. that did not produce gas from glucose was isolated from stools of 26 affected patients and blood culture from one patient. Salmonella sp. isolates with the same phenotype were isolated in three samples of marlin mousse manufactured on 27 October 2008. The constituents of the mousse were smoked marlin, raw eggs, bovine gelatin, oil, and cream. A laboratory investigation of one sample of marlin mousse manufactured 3 days later, and the individual ingredients sampled a week after production of the contaminated batch were all negative for Salmonella. Serotyping and minimum inhibitory concentration determination were performed on 12 patient isolates related to the outbreak and two mousse isolates. All isolates belonged to Salmonella serovar Typhimurium and were pansusceptible to all antimicrobials tested. Pulsed-field gel electrophoresis revealed that all the isolates were indistinguishable, thus implicating the mousse as the vehicle of the outbreak.

Extraintestinal Vibrio infections in Mauritius.

Few extraintestinal Vibrio infections have been reported in the African region. We report 3 cases from Mauritius: one case of Vibrio alginolyticus otitis externa; one case of soft tissue infection caused by non-O1 Vibrio cholerae and Vibrio parahaemolyticus; and one fatal case of non-O1 V. cholerae cellulitis and septicaemia.

Epidemiology of typhoid fever in Mauritius.

BACKGROUND: The epidemiology of typhoid fever in Mauritius was studied to determine whether there was any need for tourists visiting Mauritius to be vaccinated against the disease, and where Mauritians with typhoid fever had been infected. Data on antibiotic susceptibility of Salmonella typhi isolates from Mauritius were also analyzed. METHODS: Since 1997 every time S. typhi is isolated from blood cultures at our laboratory, an epidemiologic inquiry is conducted to determine the likely origin of the infection and the outcome of treatment, and the information collected is recorded. Results of antibiotic susceptibility testing are also noted. Data recorded on cases between 1997 and 2004 were reviewed and analyzed. RESULTS: S. typhi was isolated on 25 occasions during the 8-year period. The infection was likely to have been acquired in Mauritius in only 6 cases (24%). Another 6 cases (24%) occurred in expatriate workers from the Indian subcontinent. Of the 13 Mauritians (52%) who probably acquired the infection abroad, 11 had a history of recent travel to India. Thirteen of 14 S. typhi isolates from cases acquired in India were resistant to nalidixic acid. Of the 6 cases acquired in Mauritius, 4 occurred in children under 12 years and 1 was caused by a multiply resistant strain. Twenty-two patients made an uneventful recovery. One death was indirectly caused by typhoid fever, and there was 1 case each of intestinal perforation and relapse. CONCLUSIONS: In Mauritius typhoid fever is mainly an imported disease, but indigenous cases of the illness occur rarely and sporadically. Travelers to Mauritius need not be vaccinated against typhoid fever as the risk of acquiring the disease in the country is negligible. Mauritians traveling to India must be made aware of the risk of typhoid fever and of preventive measures. Ceftriaxone should be used as the initial first-line treatment of infection acquired in India.