Vibrio parahaemolyticus Is Associated with Diarrhea Cases in Mexico, with a Dominance of Pandemic O3:K6 Clones.

In the present study, we conducted surveillance of the V. parahaemolyticus strains present in clinical samples from six geographical regions of Mexico (22 states) from 2004 to 2011. The serotype dominance, virulence genes, presence of pandemic O3:K6 strains, and antibiotic resistance of the isolates were investigated. In total, 144 strains were isolated from the clinical samples. Seven different O serogroups and twenty-five serovars were identified. Most clinical isolates (66%, 95/144) belonged to the pandemic clone O3:K6 (tdh+, toxRS/new+ and/or orf8+) and were detected in 20 of the 22 states. Among the pandemic clones, approximately 17.8% (17/95) of the strains cross-reacted with the antisera for the K6 and K59 antigens (O3:K6, K59 serotype). Other pathogenic strains (tdh+ and/or trh+, toxRS/new-, orf8-) accounted for 26.3%, and the nonpathogenic strains (tdh- and/or trh-) accounted for 7.6%. Antimicrobial susceptibility testing showed that most of the strains were resistant to ampicillin (99.3%) but were sensitive to most tested antibiotics. The level of multidrug resistance was 1.3%. Our results indicate that pandemic O3:K6 is present in most Mexican states, thus, constant surveillance of V. parahaemolyticus strains in diarrhea patients is a public health priority and is useful for conducting risk assessments of foodborne illnesses to prevent V. parahaemolyticus outbreaks. Overall, our observations indicate that the pandemic O3:K6 clone of V. parahaemolyticus has become a relatively stable subpopulation and may be endemically established in Mexico; therefore, constant surveillance is needed to avoid new outbreaks of this pathogen.

Draft genome sequence of first Vibrio diabolicus in Mexico strain InDRE-D1-M1, an emergent threat.

INTRODUCTION: The complete genome of the marine environmental bacterium Vibrio diabolicus isolated from raw shrimp in the city of Guadalajara in the state of Jalisco in Mexico is reported here. METHODOLOGY: Vibrio spp. it was isolated and identified using standard microbiological and molecular techniques. Whole genome sequencing was performed using the Miseq system (Illumina, USA). RESULTS: The Multi Locus Sequence Typing profile of the isolated Vibrio bacteria coincided only with 4 specific loci (atpA, gyrB, pyrH and recA) and with a total coverage of the species belonging to Vibrio spp. Analysis of the complete genome of the Vibrio isolate and other closely related species, using the genomic fingerprints of the Virtual Analysis Method for PHylogenomic fingerprint estimation (VAMPHyRe) software, revealed the clustering of this species among the clade Vibrio diabolicus. The antibiogram revealed that this strain of Vibrio diabolicus is resistant to ampicillin, which is consistent with the bioinformatic finding of the ß-lactamase enzyme that hydrolyzes carbenicillin class A. CONCLUSIONS: This study demonstrated that the environmental marine bacterium Vibrio diabolicus contains carrier genes associated with pathogenicity and ecological function, which could represent a threat to public health.

Subacute coagulopathy in a randomized, comparative trial of Fab and F(ab')2 antivenoms.

BACKGROUND: Envenomation by pit vipers is associated with coagulation disorders including hypofibrinogenemia and thrombocytopenia. These abnormalities correct following antivenom treatment during the acute phase of the disease. Delayed or recurrent coagulation abnormalities have been reported following use of Fab antivenom, resulting in risk of hemorrhage or death. METHODS: We hypothesized that the longer plasma persistence of F(ab')2 antivenom, relative to Fab, in patients at risk of coagulopathy would result in decreased venonemia and coagulopathy one week after treatment. We conducted a Phase 2, randomized comparative clinical trial of rattlesnake bitten adults presenting for care in Tucson, Arizona, USA. Patients were randomly assigned to receive either Fab or F(ab')2 antivenom using a predefined treatment schedule. Endpoints included platelet counts, fibrinogen levels, and venom and antivenom ELISAs. Measurements were conducted at baseline and at various times over the following two weeks. RESULTS: Twelve patients were studied, with 6 randomly assigned to each treatment group. Early response of platelet counts, fibrinogen, and venom levels to acute treatment was similar in the two groups. One week following treatment, platelet counts and fibrinogen levels were lower in the Fab group than in the F(ab')2 group, following a characteristic pattern that reached its lowest point approximately one week after initial treatment. Venom levels dropped below detection limits in all patients following initial treatment but subsequently rebounded into the measurable range in 4 of 6 Fab cases. F(ab')2 antivenom levels demonstrated a longer plasma persistence than Fab levels, with a less rapid drop during the two days following treatment. Two patients in the Fab group had significant adverse events involving coagulation abnormalities, for which additional antivenom was administered following the initial treatment period. CONCLUSIONS: Following the acute phase of presentation and treatment for pit viper envenomation, there appears to be a roughly 2-week subacute phase of the disease during which ongoing presence of venom may result in serious delayed or recurrent coagulation defects. Late hypofibrinogenemia and thrombocytopenia are associated with recurrent venonemia and drop in antivenom levels. This pattern was apparent in patients treated with Fab antivenom but was not seen among F(ab')2 recipients in this Phase 2 study, consistent with pharmacokinetic differences between the two products. Improved understanding of Fab pharmacokinetics is important for the management of coagulopathy-prone pit viper envenomation. Use of F(ab')2 antivenom may prevent recurrent venom effects, but larger studies are necessary for statistical confirmation of this observation.