Enterica Serotype Paratyphi Research Articles

Acute febrile illness among outpatients seeking health care in Bangladeshi hospitals prior to the COVID-19 pandemic.

Understanding the distribution of pathogens causing acute febrile illness (AFI) is important for clinical management of patients in resource-poor settings. We evaluated the proportion of AFI caused by specific pathogens among outpatients in Bangladesh. During May 2019-March 2020, physicians screened patients aged ≥2 years in outpatient departments of four tertiary level public hospitals. We randomly enrolled patients having measured fever (≥100.4°F) during assessment with onset within the past 14 days. Blood and urine samples were tested at icddr,b through rapid diagnostic tests, bacterial culture, and polymerase chain reaction (PCR). Acute and convalescent samples were sent to the Centers for Disease Control and Prevention (USA) for Rickettsia and Orientia (R/O) and Leptospira tests. Among 690 patients, 69 (10%) had enteric fever (Salmonella enterica serotype Typhi orSalmonella enterica serotype Paratyphi), 51 (7.4%) Escherichia coli, and 28 (4.1%) dengue detected. Of the 441 patients tested for R/O, 39 (8.8%) had rickettsioses. We found 7 (2%) Leptospira cases among the 403 AFI patients tested. Nine patients (1%) were hospitalized, and none died. The highest proportion of enteric fever (15%, 36/231) and rickettsioses (14%, 25/182) was in Rajshahi. Dhaka had the most dengue cases (68%, 19/28). R/O affected older children and young adults (IQR 8-23 years) and was detected more frequently in the 21-25 years age-group (17%, 12/70). R/O was more likely to be found in patients in Rajshahi region than in Sylhet (aOR 2.49, 95% CI 0.85-7.32) between July and December (aOR 2.01, 1.01-5.23), and who had a history of recent animal entry inside their house than not (aOR 2.0, 0.93-4.3). Gram-negative Enterobacteriaceae were the most common bacterial infections, and dengue was the most common viral infection among AFI patients in Bangladeshi hospitals, though there was geographic variability. These results can help guide empiric outpatient AFI management.

Genome-wide analysis provides a deeper understanding of the population structure of the Salmonella enterica serotype Paratyphi B complex in Bangladesh.

The Salmonella enterica serotype Paratyphi B complex causes a wide range of diseases, from gastroenteritis to paratyphoid fever, depending on the biotypes Java and sensu stricto. The burden of Paratyphi B biotypes in Bangladesh is still unknown, as these are indistinguishable by Salmonella serotyping. Here, we conducted the first whole-genome sequencing (WGS) study on 79 Salmonella isolates serotyped as Paratyphi B that were collected from 10 nationwide enteric disease surveillance sites in Bangladesh. Placing these in a global genetic context revealed that these are biotype Java, and the addition of these genomes expanded the previously described PG4 clade containing Bangladeshi and UK isolates. Importantly, antimicrobial resistance (AMR) genes were scarce amongst Bangladeshi S. Java isolates, somewhat surprisingly given the widespread availability of antibiotics without prescription. This genomic information provides important insights into the significance of S. Paratyphi B biotypes in enteric disease and their implications for public health.

Determination Of Sonographic Common Abdominal Findings Among Patients Suffering From Typhoid Fever

Typhoid fever is a potentially multi systemic and fatal illness, and this serious systemic infection caused by salmonella enterica serotype typhi and paratyphi which are both gram-negative bacteria
 Objectives: To determine the sonographic common abdominal findings among patients suffering from typhoid fever.
 Methods: This research was conducted at Al Qaim Ultrasound Centre and Islamia Hospital Chiniot in nine months duration. Honda Electronics (HS 2000, HS 2200, and Toshiba just vision) machines were used. Frequency range of 3.5-5.00 MHz was used. All the patients were enrolled voluntarily after explaining the procedure to the patient thoroughly. Statistical Package of Social Sciences (SPSS) version 21 was used to evaluate the data
 Results: In this study 176 patients were included, which clinically diagnosed suffering from typhoid fever and laboratory findings also showing positive results. All male and female patients of all age groups, who were clinically suspected of having typhoid fever, either acute or chronic. All male and female healthy individuals and noncooperative patients. Out of 176 patients, 91 were female and 85 males. Laboratory findings, 47(26.7%),56(31.8%),21(11.9%),52(29.5%) patients having (TyphidotIgG), (TyphidotIgM), (TyphidotIgG, IgM), (Widal) positive results respectively. Common abdominal findings on ultrasonography were 62(35.2%) patients with having hepatomegaly, and 88(50%) patients with splenomegaly. Mesenteric lymph adenitis showed only in 21(11.9%) patients. Results showed 27(15.3%) patients with bowel wall thickening, and 13(7.4%) patients with having acalculous-cholecystitis.
 Conclusions: Ultrasonography is a useful and helpful tool in diagnosing the typhoid fever, especially when serological tests are time consuming or showing negative results or cultures. Ultrasonography is also a quick, economical and non-invasive procedure.

Comparison of Antibody Titre Against Salmonella Species among Healthy Individuals and Febrile Patients

Background: Widal tube agglutination test is a widely used laboratory test for diagnosis of enteric fever especially in resource limited countries where blood culture are not routinely available. We studied the titres from different groups including febrile and healthy populations in order to identify the significant agglutination titre. Materials and Methods: This was a hospital based cross-sectional study. Subjects were divided into three groups: 1) 60 healthy blood samples from volunteer students, 2) 60 febrile non-typhoidal cases and 3) 58 culture positive patient for enteric fever. Results: Among 60 apparently healthy volunteers, agglutination of ≥ 1:20 for anti O and anti-H titres against serotype Typhi were seen in 40 and 46 samples respectively. A significant proportion of sample had a titre of ≥1:80 (n=19) and 1:160 (n=14) for anti O and anti-H titres against serotype Typhi respectively among healthy individuals. Similar observations were seen in febrile non typhoidal cases except for one which had a titre of ≥1:320 for anti O and anti-H titres against serotype Typhi. In blood culture positive typhoid cases, 56 samples showed agglutinations of ≥1:80 for both anti O and anti-H titres against serotype Typhi. However two of the total sample tested showed no agglutinations. In all cases from three groups, anti-H titre for S. enterica serotype Paratyphi A and B were below 1:80. Conclusions: Widal test can be used as presumptive diagnostic tool in all the suspected cases of enteric fever if the titres are specifically raised.Keywords: enteric fever; titre; widal aggultination test.

Prevalence and Antibiogram Pattern of Salmonella enterica Serotypes inGarhwal Region: First Report from Foothills of Himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Prevalence and antibiogram pattern of Salmonella enterica serotypes in Garhwal Region: First report from foothills of himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Typhoid in Africa and vaccine deployment

Typhoid in Africa and vaccine deployment

Drug Resistance Patterns of Salmonellae Enterica Serotype Typhi and Paratyphi at a Tertiary Care Hospital of Sindh, Pakistan

The present study was conducted to evaluate drug resistance patterns of salmonella enterica serotype typhi and paratyphi in enteric fever. This study is an observational study.

Trends of Etiology and Drug Resistance in Enteric Fever in the Last Two Decades in Nepal: A Systematic Review and Meta-analysis

Prospective time-trend analyses on shifting etiology and trends of drug resistance in enteric fever are scarce. Using published and unpublished datasets from Nepal, we performed a systematic review and meta-analysis to understand the trends in etiology and resistance to antimicrobials that have occurred since 1993. Thirty-two studies involving 21 067 Salmonella enterica serotype Typhi (ST) and S. enterica serotype Paratyphi A (SPA) isolates were included. There was an increasing trend in enteric fever caused by SPA during the last 2 decades (P < .01). We observed sharply increasing trends in resistance to nalidixic acid and ciprofloxacin for both ST and SPA. In contrast, multi-drug resistance (MDR), resistance to traditional first-line antibiotics such as chloramphenicol and co-trimoxazole have significantly decreased for both organisms. The resistance to ceftriaxone has remained low, suggesting it is likely to remain useful as a reserve antibiotic for treatment. Trends in decreasing resistance to traditional first-line antibiotics and decreasing MDR provide an opportunity to reconsider these first-line antimicrobials as therapeutic options.

Identification ofIn Vivo-Induced Bacterial Proteins during Human Infection with Salmonella enterica Serotype Paratyphi A

Salmonella enterica serotype Paratyphi A is a human-restricted pathogen and the cause of paratyphoid A fever. Using a high-throughput immunoscreening technique, in vivo-induced antigen technology (IVIAT), we identified 20 immunogenic bacterial proteins expressed in humans who were bacteremic with S. Paratyphi A but not those expressed in S. Paratyphi A grown under standard laboratory conditions. The majority of these proteins have known or potential roles in the pathogenesis of S. enterica. These include proteins implicated in cell adhesion, fimbrial structure, adaptation to atypical conditions, oxidoreductase activity, proteolysis, antimicrobial resistance, and ion transport. Of particular interest among these in vivo-expressed proteins were S. Paratyphi A (SPA)2397, SPA2612, and SPA1604. SPA2397 and SPA2612 are prophage related, and SPA1604 is in Salmonella pathogenicity island 11 (SPI-11). Using real-time quantitative PCR (RT-qPCR), we confirmed increased levels of mRNA expressed by genes identified by IVIAT in a comparison of mRNA levels in organisms in the blood of bacteremic patients to those in in vitro cultures. Comparing convalescent- to acute-phase samples, we also detected a significant increase in the reaction of convalescent-phase antibodies with two proteins identified by IVIAT: SPA2397 and SPA0489. SPA2397 is a phage-related lysozyme, Gp19, and SPA0489 encodes a protein containing NlpC/P60 and cysteine, histidine-dependent amidohydrolase/peptidase (CHAP) domains. In a previous study utilizing a different approach, we found that transcripts for 11 and 7 of the genes identified by IVIAT were detectable in organisms in the blood of humans in Bangladesh who were bacteremic with S. Paratyphi A and Salmonella enterica serovar Typhi, respectively. S. Paratyphi A antigens identified by IVIAT warrant further evaluation for their contributions to pathogenesis and might have diagnostic, therapeutic, or preventive relevance.

First Report of Salmonella enterica Serotype Paratyphi A Azithromycin Resistance Leading to Treatment Failure

The prevalence of Salmonella enterica serotype Paratyphi A infection is increasing, and multidrug resistance is a well-recognized problem. Resistance to fluoroquinolones is common and leads to more frequent use of newer agents like azithromycin. We report the first case of azithromycin resistance and treatment failure in a patient with S. Paratyphi A infection.

The Case for Investing in Typhoid Vaccines

The Case for Investing in Typhoid Vaccines

Global trends in typhoid and paratyphoid Fever.

Typhoid and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and Southeast Asia, where enteric fever is associated with poor sanitation and unsafe food and water. High-quality incidence data from Asia are underpinning efforts to expand access to typhoid vaccines. Efforts are underway to develop vaccines that are immunogenic in infants after a single dose and that can be produced locally in countries of endemicity. The growing importance of Salmonella enterica serotype Paratyphi A in Asia is concerning. Antimicrobial resistance has sequentially emerged to traditional first-line drugs, fluoroquinolones, and third-generation cephalosporins, posing patient treatment challenges. Azithromycin has proven to be an effective alternative for treatment of uncomplicated typhoid fever. The availability of full genome sequences for S. enterica serotype Typhi and S. enterica serotype Paratyphi A confirms their place as monomorphic, human-adapted pathogens vulnerable to control measures if international efforts can be redoubled.

P61 Prevalence of quinolone high-resistant and ESBL producing Proteus mirabilis in Japan

We evaluated the prevalence of multidrug resistance (MDR) and production of extended spectrum beta-lactamase (ESBL) by Salmonella enterica (serotypes Typhi and Paratyphi A) in a teaching hospital in Nepal. The MDR strains of S. enterica were also tested for susceptibility to newer antibiotics.Blood cultures were obtained from 4105 patients with febrile illnesses. Isolates of S. enterica were serotyped and antibiotic susceptibility testing was carried out using disk diffusion (Kirby–Bauer) and E-tests. ESBL screening and phenotype confirmation were done following National Committee for Clinical Laboratory Standards (NCCLS) recommendations for Escherichia coli.A total of 541 isolates of S. enterica serotypes Typhi (47%) and Paratyphi A (53%) were grown. Twenty-eight isolates (5%) of S. enterica were resistant to two or more antibiotics (MDR isolates), with a greater prevalence among serotype Paratyphi A (7%). All ESBL producers (three isolates) were serotype Paratyphi A. Most of the MDR S. enterica showed reduced susceptibility to ampicillin, chloramphenicol, trimethoprim–sulfamethoxazole, ofloxacin, and ciprofloxacin, and had good susceptibility to extended-spectrum cephalosporins and carbapenems. Among the fluoroquinolones, gatifloxacin demonstrated better in vitro activity compared to levofloxacin, ciprofloxacin, and ofloxacin.A greater prevalence of S. enterica serotype Paratyphi A with higher rates of multidrug resistance and ESBL production is concerning for natives as well as travelers in Nepal since the current typhoid vaccines do not provide protection against this serotype.

Multidrug-resistant and extended-spectrum beta-lactamase (ESBL)-producing Salmonella enterica (serotypes Typhi and Paratyphi A) from blood isolates in Nepal: surveillance of resistance and a search for newer alternatives

We evaluated the prevalence of multidrug resistance (MDR) and production of extended spectrum beta-lactamase (ESBL) by Salmonella enterica (serotypes Typhi and Paratyphi A) in a teaching hospital in Nepal. The MDR strains of S. enterica were also tested for susceptibility to newer antibiotics. Blood cultures were obtained from 4105 patients with febrile illnesses. Isolates of S. enterica were serotyped and antibiotic susceptibility testing was carried out using disk diffusion (Kirby-Bauer) and E-tests. ESBL screening and phenotype confirmation were done following National Committee for Clinical Laboratory Standards (NCCLS) recommendations for Escherichia coli. A total of 541 isolates of S. enterica serotypes Typhi (47%) and Paratyphi A (53%) were grown. Twenty-eight isolates (5%) of S. enterica were resistant to two or more antibiotics (MDR isolates), with a greater prevalence among serotype Paratyphi A (7%). All ESBL producers (three isolates) were serotype Paratyphi A. Most of the MDR S. enterica showed reduced susceptibility to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ofloxacin, and ciprofloxacin, and had good susceptibility to extended-spectrum cephalosporins and carbapenems. Among the fluoroquinolones, gatifloxacin demonstrated better in vitro activity compared to levofloxacin, ciprofloxacin, and ofloxacin. A greater prevalence of S. enterica serotype Paratyphi A with higher rates of multidrug resistance and ESBL production is concerning for natives as well as travelers in Nepal since the current typhoid vaccines do not provide protection against this serotype.

Multiple-Antibiotic Resistance in Salmonella enterica Serotype Paratyphi B Isolates Collected in France between 2000 and 2003 Is Due Mainly to Strains Harboring Salmonella Genomic Islands 1, 1-B, and 1-C

This study was conducted to investigate the occurrence of multiple-antibiotic resistance among 261 clinical isolates of Salmonella enterica serotype Paratyphi B strains collected between 2000 and 2003 through the network of the French National Reference Center for Salmonella. The 47 multidrug-resistant (MDR) isolates identified (18%), were characterized on the basis of the presence of several resistance genes (bla(TEM), bla(PSE-1), bla(CTX-M), floR, aadA2, qacEdelta1, and sul1), the presence of Salmonella genomic island 1 (SGI1) by PCR mapping and hybridization, and the clonality of these isolates by several molecular (ribotyping, IS200 profiling, and pulsed-field gel electrophoresis [PFGE]) and phage typing methods. The results of PCR and Southern blot experiments indicated that 39 (83%) of the 47 S. enterica serotype Paratyphi B biotype Java MDR isolates possessed the SGI1 cluster (MDR/SGI1). Among these 39 MDR/SGI1 isolates, only 3 contained variations in SGI1, SGI1-B (n = 1) and SGI1-C (n = 2). The 39 MDR/SGI1 isolates showed the same specific PstI-IS200 profile 1, which contained seven copies from 2.6 to 18 kb. Two PstI ribotypes were found in MDR/SGI1 isolates, RP1 (n = 38) and RP6 (n = 1). Ribotype RP1 was also found in two susceptible strains. Analysis by PFGE using XbaI revealed that all the MDR/SGI1 isolates were grouped in two related clusters, with a similarity percentage of 82%. Isolation of MDR/SGI1 isolates in France was observed mainly between the second quarter of 2001 and the end of 2002. The source of the contamination has not been identified to date. A single isolate possessing the extended-spectrum beta-lactamase bla(CTX-M-15) gene was also identified during the study.

Suboptimal clinical response to ciprofloxacin in patients with enteric fever due to Salmonella spp. with reduced fluoroquinolone susceptibility: a case series.

BackgroundSalmonella spp. with reduced susceptibility to fluoroquinolones have higher than usual MICs to these agents but are still considered "susceptible" by NCCLS criteria. Delayed treatment response to fluoroquinolones has been noted, especially in cases of enteric fever due to such strains. We reviewed the ciprofloxacin susceptibility and clinical outcome of our recent enteric fever cases.MethodsSalmonella enterica Serotype Typhi (S. Typhi) and Serotype Paratyphi (S. Paratyphi) blood culture isolates (1998–2002) were tested against nalidixic acid by disk diffusion (DD) and agar dilution (AD) and to ciprofloxacin by AD using NCCLS methods and interpretive criteria. Reduced fluoroquinolone susceptibility was defined as a ciprofloxacin MIC of 0.125–1.0 mg/L. The clinical records of patients treated with ciprofloxacin for isolates with reduced fluoroquinolone susceptibility were reviewed.ResultsSeven of 21 (33%) S. Typhi and S. Paratyphi isolates had reduced susceptibility to fluoroquinolones (MIC range 0.125–0.5 mg/L). All 7 were nalidixic acid resistant by DD (no zone) and by AD (MIC 128- >512 mg/L). The other 14 isolates were nalidixic acid susceptible and fully susceptible to ciprofloxacin (MIC range 0.015–0.03 mg/L).Five of the 7 cases were treated initially with oral ciprofloxacin. One patient remained febrile on IV ciprofloxacin until cefotaxime was added, with fever recurrence when cefotaxime was discontinued. Two continued on oral or IV ciprofloxacin alone but had prolonged fevers of 9–10 days duration, one was switched to IV beta-lactam therapy after remaining febrile for 3 days on oral/IV ciprofloxacin and one was treated successfully with oral ciprofloxacin. Four of the 5 required hospitalization.ConclusionsOur cases provide further evidence that reduced fluoroquinolone susceptibility of S. Typhi and S. Paratyphi is clinically significant. Laboratories should test extra-intestinal Salmonella spp. for reduced fluoroquinolone susceptibility.

THE ETIOLOGY OF FEBRILE ILLNESS IN ADULTS PRESENTING TO PATAN HOSPITAL IN KATHMANDU, NEPAL

In Nepal, many infections remain poorly characterized, partly due to limited diagnostic facilities. We studied consecutive febrile adults presenting to a general hospital in Kathmandu, Nepal. Of the 876 patients enrolled, enteric fever and pneumonia were the most common clinical diagnoses. Putative pathogens were identified in 323 (37%) patients, the most common being Salmonella enterica serotype Typhi and S. enterica serotype Paratyphi A (117), Rickettsia typhi (97), Streptococcus pneumoniae (53), Leptospira spp. (36), and Orientia tsutsugamushi (28). Approximately half of the Salmonella isolates were resistant to nalidixic acid. No clinical predictors were identified to reliably distinguish between the different infections. These findings confirm the heavy burden of enteric fever and pneumonia in Kathmandu, and highlight the importance of murine typhus, scrub typhus, and leptospirosis. Given the lack of reliable clinical predictors, the development of cheap and accurate diagnostic tests are likely to be of great clinical utility in this setting.

Mutations in Topoisomerase Genes of Fluoroquinolone-Resistant Salmonellae in Hong Kong

A total of 88 salmonella isolates (72 clinical isolates for which the ciprofloxacin MIC was >0.06 microg/ml, 15 isolates for which the ciprofloxacin MIC was < or =0.06 microg/ml, and Salmonella enterica serotype Typhimurium ATCC 13311) were studied for the presence of genetic alterations in four quinolone resistance genes, gyrA, gyrB, parC, and parE, by multiplex PCR amplimer conformation analysis. The genetic alterations were confirmed by direct nucleotide sequencing. A considerable number of strains had a mutation in parC, the first to be reported in salmonellae. Seven of the isolates sensitive to 0.06 micro g of ciprofloxacin per ml had a novel mutation at codon 57 of parC (Tyr57-->Ser) which was also found in 29 isolates for which ciprofloxacin MICs were >0.06 micro g/ml. Thirty-two isolates had a single gyrA mutation (Ser83-->Phe, Ser83-->Tyr, Asp87-->Asn, Asp87-->Tyr, or Asp87-->Gly), 34 had both a gyrA mutation and a parC mutation (29 isolates with a parC mutation of Tyr57-->Ser and 5 isolates with a parC mutation of Ser80-->Arg). Six isolates which were isolated recently (from 1998 to 2001) were resistant to 4 micro g of ciprofloxacin per ml. Two of these isolates had double gyrA mutations (Ser83-->Phe and Asp87-->Asn) and a parC mutation (Ser80-->Arg) (MICs, 8 to 32 microg/ml), and four of these isolates had double gyrA mutations (Ser83-->Phe and Asp87-->Gly), one parC mutation (Ser80-->Arg), and one parE mutation (Ser458-->Pro) (MICs, 16 to 64 micro g/ml). All six of these isolates and those with a Ser80-->Arg parC mutation were S. enterica serotype Typhimurium. One S. enterica serotype Typhi isolate harbored a single gyrA mutation (Ser83-->Phe), and an S. enterica serotype Paratyphi A isolate harbored a gyrA mutation (Ser83-->Tyr) and a parC mutation (Tyr57-->Ser); both of these isolates had decreased susceptibilities to the fluoroquinolones. The MICs of ciprofloxacin, levofloxacin, and sparfloxacin were in general the lowest of those of the six fluoroquinolones tested. Isolates with a single gyrA mutation were less resistant to fluoroquinolones than those with an additional parC mutation (Tyr57-->Ser or Ser80-->Arg), while those with double gyrA mutations were more resistant.

Molecular properties of Salmonella enterica serotype paratyphi B distinguish between its systemic and its enteric pathovars.

Salmonella enterica serotype O1,4,5,12:Hb:1,2, designated according to the current Kauffmann-White scheme as S. enterica serotype Paratyphi B, is a very diverse serotype with respect to its clinical and microbiological properties. PCR and blot techniques, which identify the presence, polymorphism, and expression of various effector protein genes, help to distinguish between strains with systemic and enteric outcomes of disease. All serotype Paratyphi B strains from systemic infections have been found to be somewhat genetically related with respect to the pattern of their virulence genes sopB, sopD, sopE1, avrA, and sptP as well as other molecular properties (multilocus enzyme electrophoresis type, pulsed-field gel electrophoresis [PFGE] type, ribotype, and IS200 type). They have been classified as members of the systemic pathovar (SPV). All these SPV strains possess a new sopE1-carrying bacteriophage (designated PhiSopE309) with high SopE1 protein expression but lack the commonly occurring avrA determinant. They exhibit normal SopB protein expression but lack SopD protein production. In contrast, strains from enteric infections classified as belonging to the enteric pathovar possess various combinations of the respective virulence genes, PFGE pattern, and ribotypes. We propose that the PCR technique for testing for the presence of the virulence genes sopE1 and avrA be used as a diagnostic tool for identifying both pathovars of S. enterica serotype Paratyphi B. This will be of great public health importance, since strains of serotype Paratyphi B have recently reemerged worldwide.