Objective: To study Salmonella enterica serotype Typhi by pulsed-field gel electrophoresis in Hong Kong. Materials and Methods: One hundred thirty four isolates of Salmonella enterica serotype Typhi collected from 17 public hospitals and clinics in Hong Kong from 2000 to 2004 were studied in relation to epidemiological and clinical events. Isolates originated from 80 patients, with 29 patients providing multiple isolates. Susceptibility to six antibiotics was tested: ampicillin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, nalidixic acid, and ciprofloxacin. Strains were further subtyped by pulsed-field gel electrophoresis (PFGE) by separating XbaI-restricted genomic DNA of isolates. PFGE patterns that were shared between strains were further examined using restriction enzyme BlnI. Results: Of 134 S. Typhi isolates, 29 (21.6%) were resistant to at least one and up to five of the antibiotics tested. Using restriction fragments between 20 and 700 kb for analysis, the number of fragments generated by XbaI ranged from 14 to 20. Sixty-six distinct subtypes were identified in the first isolates of all 80 patients (epidemiologically unrelated) with a Simpson index of 0.993, indicating a high degree of diversity among these S. Typhi isolates. Multidrug-resistant and travel-associated S. Typhi appeared to cluster more closely than the rest of strains. Further analysis of PFGE patterns investigated the temporal relationships between the 83 strains collected from the 29 patients who gave multiple isolates. Conclusion: Dual infections or variants of the same isolates in the same patient occurred during the course of follow-up. These findings imply that PFGE data could be a valuable tool in predicting relapse, evaluating new antimicrobial drugs, and controlling the spread of typhoid disease. A regional, as well as global, typhoid bacillus fingerprint database should be set up to improve epidemiological investigations, as clinical cases easily move across national boundaries.

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.

A total of 217 and 73 strains of Salmonella enterica serotype Typhi isolated from 1985 to 1997 in Hong Kong and in 2 months of 1989 and 1990 in Vietnam, respectively, were studied. These isolates were typed by plasmid profile analysis, plasmid fingerprinting, ribotyping with PstI, and total DNA fingerprinting with NarI. There appeared to be no major outbreak of typhoid fever in Hong Kong during the study period since there was considerable heterogeneity among the isolates. Isolates from Hong Kong were different from those from Vietnam. Thirty-seven percent of Vietnamese isolates belonged to two predominant clones, with the rest being heterogeneous in nature. Total DNA fingerprinting supplemented with ribotyping could be a reliable and rapid method for epidemiological typing of S. enterica serotype Typhi.

A total of 217 and 73 strains of Salmonella enterica serotype Typhi isolated from 1985 to 1997 in Hong Kong and in 2 months of 1989 and 1990 in Vietnam, respectively, were studied. These isolates were typed by plasmid profile analysis, plasmid fingerprinting, ribotyping with PstI, and total DNA fingerprinting with NarI. There appeared to be no major outbreak of typhoid fever in Hong Kong during the study period since there was considerable heterogeneity among the isolates. Isolates from Hong Kong were different from those from Vietnam. Thirty-seven percent of Vietnamese isolates belonged to two predominant clones, with the rest being heterogeneous in nature. Total DNA fingerprinting supplemented with ribotyping could be a reliable and rapid method for epidemiological typing of S. enterica serotype Typhi.

The incidence of salmonellosis has been increasing in Hong Kong since 1989. The most common Salmonella enterica serotype isolated in 1994 was S. enteritidis. The antimicrobial susceptibilities and molecular epidemiology of 275 S. enteritidis strains isolated in this locality between 1986 and 1996 were studied. Over 99% of the isolates were susceptible to 17 of the 19 antimicrobial agents tested. One isolate harbored an autotransferring plasmid that confers resistance to tetracycline and trimethoprim-sulfamethoxazole. Another isolate harbored a mobilizable plasmid that confers resistance to ampicillin and cephalothin. This isolate was found to produce a beta-lactamase with a pI of 5.2. A total of 264 isolates (96%) were found to harbor one to five plasmids, and the majority (254) harbored a 60-kb plasmid. Of these isolates, 94% contained identical 60-kb plasmids. Based on plasmid profiles, plasmid and chromosomal fingerprints, ribotypes, and randomly amplified polymorphic DNA (RAPD) patterns, 170 (62%) isolates were allocated to group 1b. About 90% of isolates had identical or similar DNA fingerprints, ribotypes, and RAPD patterns, suggesting that a predominant clone of S. enteritidis was circulating in Hong Kong during the period being studied.

One hundred and two Shigella spp. isolated in two hospitals in Hong Kong were analysed for antibiotic resistances, resistance plasmids and plasmid profiles. Three quarters of the isolates were S. flexneri. All isolates harboured plasmids, up to a maximum of ten within one strain. Plasmids of 220 kb encoding resistances to tetracycline, chloramphenicol and sulphonamide and probably also associated with invasiveness in the Sereny test were found in 80 strains and were transferable in 18% of cases. Resistance plasmids of 92 and 99 kb were found in 27 and 15 strains respectively and encoded resistances to ampicillin, tetracycline, chloramphenicol, kanamycin, sulphonamide, trimethoprim, cotrimoxazole and gentamicin; these plasmids were usually transferable. Four plasmids of 3.9, 2.8, 2.2 and 1.8 kb were commonly found in S. flexneri strains, but were rare in other species. In contrast, there was no predominant plasmid profile in S. sonnei. S. flexneri is endemic in Hong Kong and these plasmid studies suggest that the strains in circulation are derived from only a few clones.

OBJECTIVE: To understand the epidemiology of tuberculosis (TB) inside the prison system of Hong Kong. METHOD: Prospective territory-wide TB surveillance was conducted among prisoners in 24 correctional institutions. RESULTS: From 1999 to 2005, 622 prevalent TB cases diagnosed before or within 3 months of incarceration and 214 incident cases diagnosed after 3 months were reported by prison staff to a paper-based central prison TB registry. Both crude prevalence and incidence were falling (chi(2) for trend, both P < 0.001), despite a higher sex- and age-adjusted prison TB incidence as compared to the general population (indirectly standardised rate [ISR] 280.6 vs. 108.0/100000, P < 0.001). Illegal immigrants (odds ratio [OR] 3.6, 95% confidence interval [CI] 1.8-7.4) and drug addicts (OR 2.04, 95%CI 1.13-3.7) were two major risk groups. The TB incident risk disappeared after their exclusion (ISR 117.1 vs. 108.0/100000, P = 0.52). No significant difference in the multidrug-resistant rate was found when comparing the group with the general population (3.5% vs. 1.0%, OR 3.6, 95%CI 0.5-28.4). No extensively drug-resistant (XDR) cases were identified. CONCLUSION: TB remains a significant disease in local prisons. Further strengthening of TB control programmes in prisons, especially targeting the higher risk groups, is recommended.

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.

This study was initiated throughout Hong Kong, to reveal the characteristics of community-acquired infections. All specimens collected by general practitioners from infected patients were followed prospectively, and those that were culture-positive were analysed. Four thousand seven hundred and forty-one specimens were collected from 3977 patients by 89 doctors from July 2000 to October 2001. The most common specimens were throat swabs (33%), urine (26%) and sputa (16%). The average culture-positive rate was 28%. The most common organisms were Escherichia coli (18%), beta-haemolytic streptococci (15%) and Staphylococcus aureus (12%). Fluoroquinolone resistance was relatively high (up to 35%) in organisms commonly causing urinary tract infection (E. coli, Proteus and Morganella). Although none of the pneumococci was resistant to penicillin 1 mg/L, the proportion with intermediate resistance (0.1-1 mg/L) was alarming (81%). There were three strains of methicillin-resistant S. aureus. A decrease in ampicillin resistance but a high prevalence of macrolide resistance were noted in Haemophilus influenzae. All Neisseria gonorrhoeae isolates were resistant to penicillin, up to 79% to the fluoroquinolones, 15% to spectinomycin, but all were susceptible to ceftriaxone. Respiratory pathogens (Streptococcus pneumoniae, beta-haemolytic streptococci and H. influenzae) were relatively susceptible to the newer fluoroquinolones (0-2%, 0.5-6% and 2% resistant, respectively) or third-generation cephalosporins (0-2% resistant). The distribution of organisms and their antibiotic resistance varied over time. Thus frequent surveillance is needed to provide information on the drugs of choice for different infections.

OBJECTIVES: To study the distribution of hospital isolates of enterococci from urines, bile, blood and body fluids and to evaluate different methods for the identification of enterococci. METHODS: Enterococci isolated from urine, bile, blood and body fluids collected during 1997 and 1998 were identified by polymerase chain reaction (PCR), API 20 Strep and conventional biochemical tests. RESULTS: A total of 498 non-duplicate enterococci were studied: 398 and 43 isolates from urine and bile, respectively, 49 from blood, two from cerebrospinal fluid and six from body fluids. Both API 20 Strep and PCR gave the same identification results for 240 Enterococcus faecalis isolates, 45 E. faecium isolates and one isolate each of E. gallinarum and E. Casseliflavus. These isolates were re-defined by conventional biochemical tests. PCR could correctly identify 303 (98%) isolates while API 20 Strep could only correctly identify 287 (93%) isolates (99% of E. faecalis and 57-87% of the other Enterococcus sp.). Thus, PCR was used in the identification of the remaining isolates and the identity of isolates other than E. faecalis was subsequently confirmed by biochemical tests. CONCLUSIONS: The majority of enterococci isolated was E. faecalis (81%) while only 15% were E. faecium and 4% the other enterococcal species. PCR could correctly identify E. faecalis while the identity of other enterococcal species had to be confirmed by biochemical tests.

OBJECTIVES: We aimed to study the antimicrobial susceptibilities and molecular epidemiology of Salmonella enterica serotype Derby, a unique and common salmonella serotype in Hong Kong. METHODS: Salmonella Derby strains isolated from stools of patients in a large general hospital in Hong Kong from 1989 to 1994 and from food samples isolated in the Public Health Laboratory were randomly selected and investigated for the antimicrobial susceptibilities by determining the minimal inhibitory concentrations of 19 antimicrobial agents and their relatedness using plasmid analysis, ribotyping, pulsed-field gel electrophoresis (PFGE) and total DNA fingerprinting. RESULTS: About 50% of the 127 isolates studied were susceptible to all the 19 antibiotics tested, although resistance to tetracycline (49%) and sulfamethoxazole (38%) was high. Only 12% did not harbour any detectable plasmids, while the rest contained plasmids in 51 profiles. There were two predominant clones, one comprising of 35% of isolates that could not be pulsotyped because discrete bands were not discernible after PFGE and another comprising 34% of isolates that could be pulsotyped. The remaining 31% belonged to a variety of types. CONCLUSIONS: Approximately 70% of S. Derby belonging to two clones were endemic in the community, while the remaining isolates belonged to a variety of types which were probably a result of sporadic infection. The sources of human infections were foods, since most isolates from foods also belonged to the two endemic clones. Typing of S. Derby isolates from other sources such as animals or the environment would help elucidate how foods were contaminated. PFGE might not be universally applicable to all salmonella strains.

We investigated the antimicrobial susceptibilities and molecular epidemiology of 200 strains of Salmonella enterica serotype typhimurium isolated from 1989 to 1996 in Hong Kong. Only 22% of strains were susceptible to all 19 antibiotics tested but all were susceptible to second- and third-generation cephalosporins. Up to 9% of strains were resistant to 0.12 mg/l concentrations of ciprofloxacin or ofloxacin but none were resistant to 1 or 2 mg/l concentrations of these 2 drugs, respectively. The isolates were grouped into 15 types by ribotyping with restriction endonuclease EcoRI and into 53 types by pulsed-field gel electrophoresis of XbaI-restricted DNA fragments. When DNA fragments of the ribotypes and pulsotypes were pooled and analyzed 87 types resulted, 76 (87%) of which were of > 90% similarity and were grouped into 15 clusters. About 60% of the isolates belonged to 3 clusters, which probably represented 3 clones endemic in the community. The rest of the isolates were of a large variety of types or clusters. For epidemiological purposes analysis of pooled results from different molecular techniques would be more discriminative than results from individual techniques alone.

Due to emerging resistance to traditional antimicrobial agents, such as ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol, azithromycin is increasingly used for the treatment of invasive Salmonella infections. In the present study, 696 isolates of non-Typhi Salmonella collected from humans, food animals, and retail meats in the United States were investigated for antimicrobial susceptibility to azithromycin. Seventy-two Salmonella enterica serotype Typhi isolates from humans were also tested. For each isolate, MICs of azithromycin and 15 other antimicrobial agents were determined by broth microdilution. Among the non-Typhi Salmonella isolates, azithromycin MICs among human isolates ranged from 1 to 32 μg/ml, whereas the MICs among the animal and retail meat isolates ranged from 2 to 16 μg/ml and 4 to 16 μg/ml, respectively. Among Salmonella serotype Typhi isolates, the azithromycin MICs ranged from 4 to 16 μg/ml. The highest MIC observed in the present study was 32 μg/ml, and it was detected in three human isolates belonging to serotypes Kentucky, Montevideo, and Paratyphi A. Based on our findings, we propose an epidemiological cutoff value (ECOFF) for wild-type Salmonella of ≤16 μg/ml of azithromycin. The susceptibility data provided could be used in combination with clinical outcome data to determine tentative clinical breakpoints for azithromycin and Salmonella enterica.

Salmonella enterica serotype Newport is an important cause of non-typhoidal salmonellosis, a clinically less severe infection than typhoid fever caused by S. enterica serotype Typhi. In this investigation, the virulence genotypes of S. enterica Newport isolated from a backwater environment were compared with Salmonella Typhi from clinical cases in the same region where salmonellosis is endemic. Genotyping was done by PCR screening for virulence markers associated with Salmonella pathogenicity islands (SPIs) and plasmids. The virulence genes associated with SPIs I-VI were detected in 95-100% of all the isolates, while the viaB locus representing SPI-7 was detectable in 66 and 73% of the environmental and clinical isolates, respectively. A significant number of Salmonella Newport lacked virulence genes shdA and sopE compared to S. Typhi. All S. Typhi and S. Newport isolates lacked large plasmid-borne virulence genes spvR and pefA. Further investigations into the antimicrobial resistance of S. Newport revealed multiple drug resistance to ampicillin, amoxicillin/clavulanic acid, trimethoprim-sulfamethoxazole, chloramphenicol, tetracycline, cephalothin, and cephalexin. In comparison, S. Typhi were susceptible to all clinically relevant antimicrobials. The results of this study will help in understanding the spread of virulence genotypes and antibiotic resistance in S. Newport in the region of study.

BACKGROUND: Typhoid fever continues to remain a major public health problem, especially in regions such as Gulbarga, due to poor sanitation and personal hygiene. Gulbarga region is often prone to enteric fever outbreaks and is an endemic region of typhoid fever. Enteric fever caused by Salmonella Typhi has not been adequately explored in this region. METHODOLOGY: A total of 95 isolates of S. Typhi collected from different clinical and environmental sources were tested for antimicrobial susceptibility according to the CLSI guidelines. MIC of resistant isolates to various antibiotics was performed by agar dilution method. RESULTS: Of the total isolates studied, 10% were found to be multidrug resistant (MDR)(defined as resistance to ampicillin, chloramphenicol and co-trimoxazole). There was a decrease in the susceptibility to ciprofloxacin of S. Typhi with MIC showing an upward trend (0.125-4microg/mL). Concurrently, there has been an increase in the number of isolates sensitive to all antibiotics except nalidixic acid. CONCLUSION: MDR S. Typhi continues to be an important public health issue in Gulbarga. Presence of quinolone resistance and associated low-level ciprofloxacin resistance is a concern and requires further study.

Enteric fever due to Salmonella enterica is a major health problem, and fluoroquinolones such as ciprofloxacin are mostly the antibiotic of choice for the treatment. Resistant to ciprofloxacin has been noticed to increase that due to emergence of new mutations in the bacterial DNA. This study was conducted to explore the fluoroquinolone resistance and molecular characterization of reduced quinolone susceptibility in S. typhi and S.paratyphi A in Kuwait. METHODS: A total of 136 clinical isolates of S.typhi and 40 of S. paratyphi A were collected over 5 years. The antimicrobial susceptibility was studied by various methods. DNA sequencing of gyrA, gyrB, parC and parE genes were performed in 31 isolates. Results demonstrated that a substantial difference in MIC range between the two serotypes with the most common MIC for S. typhi being 0.25 mg /L and for S. paratyphiA being 1 mg/L. The proportion of nalidixic acid resistant (NAR) strains increased gradually over the years. These strains had a significantly higher range of MIC of ciprofloxacin (0.023 mg/L inverted exclamation markV 1.0 mg/L) as compared to the nalidixic acid sensitive (NAS) strains (0.0016 mg/L inverted exclamation markV 0.125 mg/L). DNA sequencing of gyrA gene showed the presence of three different point mutations: Ser83toPhe in 17 strains, Ser83 to LEU in 3 strains and Asp 87toAsn in 6 strains. No mutations in the other genes were found. CONCLUSIONS: It is very important to keep searching for new mutations and continuously monitoring drug-resistance in different parts of the world to efficiently manage cases with enteric fever.

BACKGROUND AND OBJECTIVES: Chloramphenicol was considered the anti-microbial gold standard for typhoid treatment but, following the increasing worldwide frequency of antibiotic resistance, ciprofloxacin has been the mainstay of therapy since 1980. Recent studies have shown a shifting of susceptibility to conventional drugs like chloramphenicol, ampicillin and cotrimoxazole. The primary objective of the study was to evaluate the in vitro activity of chloramphenicol and other first-line drugs in comparison with cephalosporins and quinolones. MATERIALS AND METHODS: Fifty isolates of Salmonella obtained from blood culture were subjected to serotyping at the Central Research Institute, Kasauli. Phage typing and biotyping was performed at the National Phage Typing Centre, New Delhi. Antibiotic sensitivity testing was carried out for 10 drugs by the Kirby-Bauer disc diffusion method and minimum inhibitory concentration by broth microdilution for nalidixic acid, chloramphenicol, ciprofloxacin, ceftriaxone, cefixime and ofloxacin. Multi-drug-resistant (MDR) strains were checked for plasmid. RESULTS: In the present study, 70 and 30% of the isolates were Salmonella enterica serovar typhi and paratyphi A, respectively. They were highly sensitive to chloramphenicol (86%), ampicillin (84%) and cotrimoxazole (88%). Highest sensitivity was seen for cephalosporins, followed by quinolones. Seventeen/21 (81%) and 100% of the Salmonella enterica serovar typhi strains belonged to E1 phage type and biotype 1, respectively. Antibiogram showed 2% of the strains to be sensitive to all the drugs tested and 12% were MDR and showed the presence of plasmids. CONCLUSION: The study indicates reemergence of chloramphenicol-susceptible Salmonella enterica serovar typhi and paratyphi A isolates, a significant decline in MDR strains and high resistance to nalidixic acid. E1 phage type and biotype 1 are found to be most prevalent in Chennai, India.

BACKGROUND: Enteric fever caused by Salmonella enterica serovar Typhi has not been adequately explored in Jordan. METHODOLOGY: In this study we investigated antibiotic resistance patterns and resistance determinants coupled with fingerprint methods of forty-eight isolates of S. Typhi obtained from 113 patients with suspected enteric fever admitted at six governmental hospitals in different directorates in Jordan. Twenty-four isolates were from an outbreak of typhoid fever that occurred between October 2004 and January 2005, and another twenty-four were from sporadic cases from 2005. RESULTS: All isolates of S. Typhi were resistant to streptomycin. A multidrug resistant (MDR) pattern of ampicillin, chloramphenicol, co-trimoxazole with tetracycline and streptomycin (R-type ACCoTS) was found in 58% of the epidemic strains causing the outbreak and in 98% of the strains from sporadic cases. MDR isolates harbored a single IncHI1 plasmid containing a class 1 integron (dfrA7). Plasmid conjugation studies demonstrated a genetic transfer of resistance (ACCoT). S. Typhi isolates were all sensitive to fluoroquinolones and cefotaxime, the alternative drugs recommended for treatment of typhoid fever. The genomic analysis using PFGE showed: a) the outbreak was caused by an introduced circulating clone with/without an MDR plasmid, and b) isolates from the sporadic cases from 2005 are the same MDR clone that persisted and spread in the country. CONCLUSION: The emergence of MDR S. Typhi strains is a majorn important public health issue in Jordan. This study should guide selection of effective antibiotic therapy for the treatment of typhoid and monitoring of the spread of MDR of S. Typhi.

SUMMARYThe phage types and antimicrobial susceptibilities of 226 isolates of Salmonella enterica serovar Typhi from imported cases in Japan between 2001 and 2006 were investigated. Most (93.8%) had travelled to Asian countries, particularly South East Asia. Twenty-one phage types were identified with E1 (30.5%), UVS (15.9%) and B1 (9.3%) being the most common. The frequency of multidrug-resistant strains reached 37.0% in 2006 with phage types E1 and E9 predominating. Almost half (48.2%) of the isolates were resistant to nalidixic acid and two isolates displayed high-level fluoroquinolone resistance. Three mutations, two in gyrA and one in parC, were identified in both isolates.

Ciprofloxacin has become the antibiotic of choice for the treatment of typhoid fever with the emergence and worldwide spread of Salmonella enterica typhi strains resistant to chloramphenicol. However, the rampant use of ciprofloxacin gradually led to an increase in its minimum inhibitory concentration against S. enterica typhi. This threatened its therapeutic efficacy and resulted in the re-emergence of chloramphenicol-sensitive S. enterica typhi strains.

Salmonella enterica serotype typhi continues to be an important public health problem in Kuwait. Analysis of the isolates from 163 patients, collected between 1995 and 2003, showed that the majority were from patients from the Indian sub-continent, including 45 from Bangladesh, 38 from India and 30 from Pakistan. Fifty-four of the strains showed multiple antibiotic resistance (MDR). Twenty-five strains were from Kuwaitis, with 15 aged <18 years. Bacteriophage typing of 20 isolates from Kuwaitis revealed that they belonged to 8 different phage types, and that the 3 MDR strains were phage type E1. Random amplified polymorphic DNA typing showed genetic variability amongst isolates from Kuwaiti patients. This method conveniently demonstrated the identity of 4 isolates associated with a small outbreak. 48 isolates from 2002-3 were tested for reduced susceptibility to quinolones. 12 of 18 MDR strains and 7/30 susceptible strains showed reduced susceptibility to ciprofloxacin (minimum inhibitory concentration 0.125-0.5 mg/L). All 12 strains were tested for mutation in the quinolone resistance determining region (QRDR) of the gyr A gene. The mutation ser83 phe was detected in the 10 strains tested. Thus typhoid fever in Kuwait is predominantly associated with those who have traveled from endemic areas to work in Kuwait. The incidence of MDR strains remains at about 30%. Reduced susceptibility to ciprofloxacin in MDR S. typhi has increased from (11%) in 1995-1996 to (67%) in 2002-2003 and from (0%) to (23%) in susceptible strains. Mutation of the gyrA gene is the mechanism most often responsible.

SUMMARYTwo hundred and four Salmonella enterica serotype Typhi (S. Typhi) isolates were collected from seven Asian countries during 2002-2004. Multidrug-resistant S. Typhi (resistant to 3 antibiotics) was detected in 84 (41.2%) isolates and 142 (69.6%) showed reduced susceptibility to ciprofloxacin (minimum inhibitory concentration=0.125-1.0 mg/l). This study highlights the worsening situation of antimicrobial resistance of S. Typhi in Asia.