Diversity of pulsed-field gel electrophoresis pulsotypes, serovars, and antibiotic resistance among Salmonella isolates from wild amphibians and reptiles in the California Central Coast.

A survey of cold-blooded vertebrates and associated surface waters in a produce-growing region on the Central California Coast was done between May and September 2011 to determine the diversity of Salmonella. Samples from 460 amphibians and reptiles and 119 water samples were collected and cultured for Salmonella. Animals sampled were frogs (n=331), lizards (n=59), newts (n=5), salamanders (n=6), snakes (n=39), and toads (n=20). Salmonella was isolated from 37 individual animals, including frogs, lizards, snakes, and toads. Snakes were the most likely to contain Salmonella, with 59% testing positive followed by 15.3% of lizards, 5% of toads, and 1.2% of frogs. Fifteen water samples (12.6%) were positive. Twenty-two different serovars were identified, and the majority of isolates were S. enterica subsp. IIIb, with subsp. I, II, and IIIa also found. The serovar isolated most frequently was S. enterica subsp. IIIb 16:z10:e,n,x,z15, from snakes and frogs in five different locations. S. enterica subsp. I serovar Typhimurium and the monophasic I 6,8:d:- were isolated from water, and subspecies I Duisburg and its variants were found in animals and water. Some samples contained more than one type of Salmonella. Analysis of pulsed-field gel electrophoresis pulsotypes indicated that some strains persisted in animals and water collected from the same location. Sixty-six isolates displayed antibiotic resistance, with 27 isolates resistant to more than one antibiotic, including a subspecies IIIb isolate from snake having resistance to five different antibiotics. Twenty-three isolates were resistant to more than one class of antibiotic, and six isolates were resistant to three classes. While these subspecies of IIIa and IIIb cause fewer instances of human illness, they may serve as reservoirs of antibiotic resistance, determinants in the environment, and be sources of contamination of leafy greens associated with product recalls.

Molecular characterization of extended-spectrum cephalosporinase-producing Salmonella enterica serovar Choleraesuis isolates from patients in Thailand and Denmark.

The objective of this study was to characterize extended-spectrum cephalosporinase (ESC)-producing isolates of Salmonella enterica serovar Choleraesuis recovered from patients in Thailand and Denmark. Twenty-four blood culture isolates from 22 patients were included in the study, of which 23 isolates were recovered from 21 Thai patients during 2003, 2007, or 2008 and one isolate was recovered from a Danish traveler to Thailand. ESC production was confirmed in 13 out of the 24 isolates by MIC testing. Microarray and plasmid profiling (replicon typing and restriction fragment length polymorphism [RFLP]) were used to characterize the genetic mechanisms of antimicrobial resistance in the 13 ESC-producing isolates. Pulsed-field gel electrophoresis (PFGE) and MIC testing were used to compare the clonality between the 13 ESC-producing isolates and the 11 non-ESC-producing isolates. Based on susceptibility patterns, the ESC-producing isolates were more closely related than non-ESC-producing isolates. Microarray, PCR, plasmid profiling, and replicon typing revealed that the 13 ESC-producing isolates harbored either bla(CMY-2) containing incA/C or bla(CTX-M-14) containing incFIIA, incFrepB, and an unknown replicon located on plasmids ranging in size from 75 to 200 kb. The RFLP and replicon typing clustered the isolates into four distinct groups. PFGE revealed 16 unique patterns and five clusters; each cluster contained two or three of the 24 isolates. The isolate from the Danish patient was indistinguishable from two Thai clinical isolates by PFGE. This study revealed the emergence of the bla(CTX-M-14) gene among several clones of Salmonella serovar Choleraesuis. Numerous plasmids were identified containing up to two different ESC genes and four distinct replicons. A "travel-associated" spread was confirmed. Overall, a high degree of clonal diversity between isolates resistant and susceptible to cephalosporins was observed. The findings represent a serious threat to public health for the Thai people and tourists.

Rapid identification of Salmonella enterica subsp. arizonae and S. enterica subsp. diarizonae by real-time polymerase chain reaction.

Reptiles are popular as pets, leading to an increased risk of human infections due to uncommon Salmonella strains including the Arizona group (subspecies arizonae and diarizonae). We present a real-time Arizona-specific polymerase chain reaction demonstrating 100% specificity and 99.6% sensitivity, offering savings in time and labor over traditional identification methods.

Structural and serological studies of lipopolysaccharides of Citrobacter O35 and O38 antigenically related to Salmonella.

Structural analysis using 13C NMR spectroscopy and methylation showed that lipopolysaccharides (LPSs) of Citrobacter freundii O35 and Salmonella arizonae O59 have structurally identical O-specific polysaccharide chains, and those of C. freundii O38 and Salmonella kentucky differ only in the presence of O-acetyl groups in the former. Serological relationships between the structurally similar LPSs were demonstrated using inhibition of ELISA, rocket immunoelectrophoresis, double gel diffusion, and immunoblotting. The O-acetyl groups present in C. freundii O38 LPS are of little importance for its serological specificity. A cross-reaction was observed in immunoblotting between O-antisera to C. freundii O35 and S. arizonae O59 and a structurally related LPS of Pseudomonas aeruginosa O11a, 11b (Lányi-Bergan classification).

Salmonella arizonae in the United Kingdom from 1966 to 1990.

Salmonella arizonae are rarely isolated in the UK. Since 1966 there have been sixty-six isolates from humans of whom 35% gave a recent history of foreign travel. Terrapins and snakes are potential sources of infection.

[Evaluation of the Autoscan-4 System for the identification of strains of the genus Salmonella]. / Evaluación del sistema Autoscan-4 en la identificación de cepas del género Salmonella.

A study was performed to compare the Autoscan-4 with conventional biochemical methods to identify isolates of the Salmonella genus. The Autoscan-4 yielded correct identification of the 99% Salmonella isolates at the genus and species level, but failed to identify 74% Salmonella isolates of the "Arizona" group, making necessary to perform subspecies biochemical reactions.

Pet turtles: a continuing international threat to public health.

The occurrence of Salmonella spp. in red-eared (Pseudemys scripta elegans) turtle eggs imported into Canada from Louisiana in June to September 1988 was examined. Of 28 lots tested, six (21%) lots from three of four exporters harbored salmonellae. Salmonella poona and Salmonella arizonae were frequently encountered in both fertile eggs and packaging moss. Turtles hatched in our laboratory from affected lots of eggs shed Salmonella in tank water for up to 11 months. Widespread use of gentamicin on turtle farms to produce Salmonella-free eggs for export apparently encouraged development of antibiotic resistance in bacterial strains. Of 37 Salmonella strains isolated in this study, 30 (81%) were gentamicin resistant. Such high levels of antibiotic-resistant salmonellae in turtle eggs pose a serious human health risk. Further marketing of turtle eggs and hatchlings should be curtailed until consistent production and distribution of Salmonella-free stocks can be assured.

A new Salmonella serovar S.III b 58:z10:z53:Rz50.

A new Salmonella serovar S.III b 58:z10:z53:Rz50 was isolated from the water samples of Ashida river, Fukuyama city, Japan. Its antigenic structure is described.

Occurrence and distribution of serotypes of the Arizona subgroup of Salmonella strains in the United States from 1967 to 1976.

The Salmonella Arizona subgroup contains gram-negative enteric bacteria that are closely related to other salmonellae biochemically, serologically, and genetically. Although the Arizona subgroup may be isolated from a wide variety of nonhuman and human sources, the arizonae are uncommonly recognized as human pathogens, and surprisingly little is known about their epidemiology. From 1967 through 1976, the Centers for Disease Control received 858 Arizona subgroup cultures from human and nonhuman sources representing 143 different serotypes in 33 somatic groups; several serotypes had not been previously reported. The 374 cultures from humans represent 71 different serotypes; extraintestinal isolates were present in 31 (44%) serotypes. Compared with data from a previous 20 years of surveillance, the proportion of Arizona subgroup strains isolated from stools, blood, and other sites was remarkably stable, but several serotypes showed marked changes in their frequency of isolation. In total, the ratio of extraintestinal to intestinal isolates was 0.37, but marked serotype-specific variation was noted, suggesting differences in virulence associated with serotype.

Evaluation of a new screening system for enteric pathogens.

The two-hour Rapid SST strip (DMS Laboratories, Inc.) was compared with our standard screening system (triple sugar iron agar, lysine iron agar, and urea) for enteric pathogens. We tested 50 stock cultures of enteric pathogens and 213 stool cultures received in the Barnes Hospital Clinical Microbiology Laboratory over a two-month period. All enteric pathogens from the stock cultures and clinical specimens were identified correctly with the Rapid SST system. More false-positive reactions were observed with the Rapid SST system (34%) than with the conventional system (23%). However, the costs associated with using both systems were equivalent and the test results were available one day faster with the Rapid SST system. Thus, the Rapid SST is a rapid, accurate, and cost-effective method for screening stool specimens for enteric pathogens.

[Four new Salmonella species and three serological variants of subgenus III (Arizona) (author's transl)]. / Vier neue Salmonella-Species und drei serologische Varianten des Subgenus III (Arizona).

Four new strains of Salmonella and three serological variants described in this paper were isolated from free living snakes (Vipera berus L. and Natrix natrix L.) of Northern Germany. All strains belong to the subgenus III of the genus Salmonella. For the first time a representative of subgenus III in the Salmonella group M with the serological formula S. arizonae 28:Z10:Z57 was isolated. 1) S. (6),14:1,v:z (Ar. 7 a,7c:23-31) 2) S. 17:Z10:e,n,X,Z15:Z56 (Ar. 12:27-28-38) 3) S. 21:1,v:Z57 (Ar. 22:23-40a,40c) 4) S. 28:Z10:Z57 (Ar. 35:27-40a,40c) 5) S. 38:(k):Z35:Z56 (Ar. 16:22-21-38) 6) S. 43:1,v:Z56 (Ar. 21:23-38) 7) S. 50:Z10:Z:Z56 (Ar. 9a,9c:27-31-38)

[Serological integration of all known Arizona-species into the Kauffmann-White-scheme (author's transl)]. / Serologische Integration aller bekannten Arizona-Species in das Kauffmann-White-Schema.

This paper reports on the integration of the Arizona group as sub-genus III into the K. W.-Schema. For many years comparative serological analyses of all serotypes belonging to sub-genus III have been carried out and detailed antigenic formulae have been established which now, for the first time, are published in full. These detailed antigenic formulae are not only of the utmost significance for the precise definition of serotypes but are also of immense importance to reference laboratories, in particular for the production of specific diagnostic sera, their correct absorption and specificity control.