Inhibitory effects of several essential oils towards salmonella typhimurium, salmonella paratyphi A and salmonella paratyphi B

Plant essential oils are natural products extracted from plants and because of their antimicrobial properties can be used as natural additives in foods. They are also useful for decontamination of food-borne pathogens and can be a safe additive in foods. The antimicrobial activities of essential oils belonging to Saturiea hortensis, Thymus vulgaris, Mentha polegium, Cuminum cyminum, Lavandula officinalis and Mentha viridis L. [spearmint] were investigated at different concentrations [0.1, 0.3, 0.5, 1, 2, 5 and 10%v/v] against Salmonella typhimurium, Salmonella paratyphi A and Salmonella paratyphi B by using the agar well diffusion method. Essential oils showed inhibitory effect on Salmonella spp. in the agar well diffusion assay. In addition, the capability of essential oils for decontamination of minced row beef, ground beef, minced raw chicken and minced raw fish inoculated with Salmonella spp. at 0.1 and 0.5%v/v were assessed. Reduction of the Salmonella spp. population was observed following the inoculation of the cultures with 0.1 and 0.5%v/v essential oils

Clinical presentation and drug resistance patterns of Salmonellae typhi and paratyphi at a tertiary care hospital of Sindh

The aim of this study is to evaluate the clinical presentation and drug resistance patterns of Salmonellae typhi and paratyphi. Observational Descriptive Study. This study was conducted at the Muhammad Medical Hospital Mirpurkhas, from Jan 2010 to April 2011. One hundred twenty six patients were studied, who satisfied the clinical and laboratory criteria of typhoid/ paratyphoid fever. The blood samples, 5-10 ml from adults were inoculated directly into blood culture bottles. Subcultures were also performed. Antibiotic sensitivity was tested by the Kirby-Bauer technique according to Clinical and Laboratory Standards Institute guidelines. Statistical analysis was performed on SPSS version 10.9 [Chicago, Illinosis, USA], using the chi-square test and student's t-test for the qualitative and quantitative variables respectively. The identified organisms were S.typhi observed in 91 [72.22%], both S typhi/paratyphi in 18 [14.28%] and S.paratyphi A and B in the rest 17 [13.49%]. In 97 [76.98%] of patients, antibody O titers were >/= 1:160 and in 39 [30.95%] titers were <1:160. The overall multi-drug resistant isolates were found in >80% for the first line agent's i.e.; ampicillin, amoxicillin, cotrimoxazole and chloramphenicol. The highest sensitivity rate was found for the cefixime [98.41%] and the lowest one for the ampicillin [22.2%]. We found drug resistant and multi-drug resistant salmonellae in our study; this may be because of antibiotic use as self medication, medication by pharmacist and quacks

Antimicrobial resistance in typhoidal salmonellae.

Infections with Salmonella are an important public health problem worldwide. On a global scale, it has been appraised that Salmonella is responsible for an estimated 3 billion human infections each year. The World Health Organization (WHO) has estimated that annually typhoid fever accounts for 21.7 million illnesses (217,000 deaths) and paratyphoid fever accounts for 5.4 million of these cases. Infants, children, and adolescents in south-central and South-eastern Asia experience the greatest burden of illness. In cases of enteric fever, including infections with S. Typhi and S. Paratyphi A and B, it is often necessary to commence treatment before the results of laboratory sensitivity tests are available. Hence, it is important to be aware of options and possible problems before beginning treatment. Ciprofloxacin has become the first-line drug of choice since the widespread emergence and spread of strains resistant to chloramphenicol, ampicillin, and trimethoprim. There is increase in the occurrence of strains resistant to ciprofloxacin. Reports of typhoidal salmonellae with increasing minimum inhibitory concentration (MIC) and resistance to newer quinolones raise the fear of potential treatment failures and necessitate the need for new, alternative antimicrobials. Extended-spectrum cephalosporins and azithromycin are the options available for the treatment of enteric fever. The emergence of broad spectrum β-lactamases in typhoidal salmonellae constitutes a new challenge. Already there are rare reports of azithromycin resistance in typhoidal salmonellae leading to treatment failure. This review is based on published research from our centre and literature from elsewhere in the world. This brief review tries to summarize the history and recent trends in antimicrobial resistance in typhoidal salmonellae.

Occurrence & antibiogram of Salmonella Typhi & S. Paratyphi A isolated from Rourkela, Orissa.

Background & objectives: Almost round-the-year occurrence of Salmonella Typhi and Salmonella Paratyphi A has been noticed in Rourkela since last 13 and five years respectively. The incidence of infection along with the antibiogram of these two serotypes in this area were carried out. Methods: The study was carried out at Ispat General Hospital, Rourkela, India, between January 2005 and December 2008 with 5340 blood samples collected from patients with suspected enteric fever and pyrexia of unknown origin. Isolation, identification and antibiogram of the causative organisms were performed according to standard bacteriological procedures. Results: A total of 298 Salmonella isolates showed an overall per cent positivity of 5.58. Multidrug resistance was found in 11.96 per cent and 15.62 per cent isolates of S. Typhi and S. Paratyphi A respectively. Less than 2 per cent isolates of Salmonella showed resistance to ciprofloxacin. A resistance of 3.0 to 6.25 per cent against third generation cephalosporins was observed among the salmonella isolates. Interpretation & conclusion: A round-the-year occurrence of Salmonella spp. in Rourkela might have been due to the presence of a considerable number of carriers in the locality, poor sanitation in nearby slum areas, and inadequate and contaminated community water supply at times. Higher degree of susceptibility among S. Typhi isolates against various antibiotics was encouraging, but increasing trend of resistance observed among S. Paratyphi A isolates was a matter of concern.

Evaluation of the current trend of nalidixic acid susceptibility in typhoidal Salmonellae; a marker of therapeutic failure for the fluoroquinolones

Typhoid is a major health problem faced by the developing countries like Pakistan. More than 20 million cases are reported annually worldwide. Currently fluoroquinolones are the drugs of choice to treat typhoid fever. In vivo resistance to fluoroquinolones leading to therapeutic failure is developing rapidly and is becoming a major concern for the clinicians. The objective of this study was to determine the sensitivity pattern of Nalidixic acid over the last four years. A descriptive cross sectional study was carried out at the Microbiology Department of the Army Medical College, National University of Sciences and Technology, Rawalpindi from January 2006 to December 2009. All the isolates were dealt with standard microbiological procedures. The antimicrobial sensitivity of Nalidixic acid and Ciprofloxacin was determined using Kirby-Bauer disc diffusion method as per the guidelines of Clinical and Laboratory Standard Institute [CLSI]. Out of 240 isolates, 111 were Salmonella typhi and 129 were Salmonella paratyphi A. The resistance of the typhoidal Salmonella to Nalidixic acid has reached significant levels and it seems only a matter of time when hundred percent resistance will be encountered. All isolates were sensitive to Ciprofloxacin on disc diffusion method. Resistance to Nalidixic acid predicting therapeutic failure with fluoroquinolones is on a steady rise

An increase in enteric fever cases due to Salmonella Paratyphi A in & around Chandigarh.

BACKGROUND & OBJECTIVE: Enteric fever is a major public health problem in India. It is classically caused by Salmonella enterica serotype Typhi. Salmonella enterica serotype Paratyphi A which had been reported less frequently from cases of enteric fever has shown an increasing trend since 1996 in India. There is also variation in the antimicrobial susceptibility of Salmonella Paratyphi A from different parts of the country. An attempt is therefore made to study the rate of isolation and antimicrobial susceptibility pattern of Salmonella Paratyphi A from cases of enteric fever coming to a tertiary care hospital at Chandigarh. METHODS: The blood samples of patients suspected of having enteric fever and admitted to Government Medical College and Hospital, Chandigarh, from January 2006 to April 2007 (11,240) were processed by conventional methods. Antimicrobial susceptibility was tested by Kirby-Bauer disc diffusion method. The minimum inhibitory concentration to two antibiotics- ciprofloxacin and chloramphenicol was determined by agar dilution technique. Simultaneously, retrospective analysis was done from January 2003-December 2005 to study any difference in the incidence and antimicrobial susceptibility pattern of Salmonella Paratyphi A among enteric fever patients. RESULTS: Of 305 total isolates, 231 were S. Typhi and 84 S. Paratyphi A rise. The number of Salmonella Paratyphi A cases rose from 27 in 2006 (34.18%) to 13 (40.63%) in four months of 2007. All were sensitive to ciprofloxacin and cefotaxime but MIC to ciprofloxacin was raised (0.125-0.5 microg/ml). Resistance to nalidixic acid was 92.5 per cent. Chloramphenicol sensitivity re-emerged with 90 per cent isolates sensitive to it while sensitivity to ampicillin dropped (72.5%) as compared to previous years. Only one isolate was multi-drug resistant. INTERPRETATION & CONCLUSION: The present study conferencing Salmonella Paratyphi A as the rapidly emerging pathogen of enteric fever. With increasing resistance to fluoroquinolones and possibility of re-emergence of sensitivity to chloramphenicol, the policy of empirical treatment of enteric fever needs to be rationalized.

Etiological agents of bacteraemia and antibiotic susceptibility pattern in Kathmandu Model Hospital.

The presence of bacteria in blood is simply known as bacteraemia. The main aim of this study is to determine the bacteraemia in patients visiting Kathmandu Model Hospital and antibiotic susceptibility pattern of isolates with special interest on ciprofloxacin. This prospective study was carried out in microbiology laboratory, Kathmandu Model Hospital from April 2005 to June 2005. Standard procedure was followed for blood sample collection. The bacteria were isolated and identified by standard microbiological procedure. Further, antibiotic susceptibility test was determined by NCCLS recommended Kirby-Bauer disc diffusion method. Out of 532 culture requests, 123 samples showed evidential microbial growth. The number of isolate of Salmonella typhi, Salmonella paratyphi A and Escherichia coli were 78, 44 and one respectively. The antibiotic susceptibility test demonstrated that chloramphenicol was the foremost drug of choice among the tested antibiotics with its sensitive rate of 98.4%. All the isolates of Salmonella typhi were susceptible to ceftriaxone and all isolates of Salmonella paratyphi A were susceptible to chloramphenicol, cotrimoxazole and amoxycillin. Ciprofloxacin resistant serotype of Salmonella was not isolated but out of 16 isolated serovar of Typhi and 10 serovar of Paratyphi A screened with nalidixic acid, 10 serovar of Typhi and all serovar of Paratyphi A were found to be resistant. Three isolates of Salmonella typhi were found as multidrug resistant (MDR) whereas no MDR was found in Salmonella paratyphi A. From this it can be concluded that Salmonella bacteraemia is more than other. Although nalidixic acid resistant serovars were isolated, ciprofloxacin resistant serovar were not present.

High level ciprofloxacin resistance in Salmonella enterica isolated from blood.

PURPOSE: Over the last few years, resistance to ciprofloxacin in Salmonella enterica has become a global concern. The present study was undertaken to find out the susceptibility pattern of Salmonella enterica isolates in our hospital. METHODS: Blood cultures were done using BacT/ALERT 3D system. The antimicrobial susceptibility testing was carried out by the Kirby-Bauer disc diffusion method using CLSI breakpoints. Minimum inhibitory concentration was determined for ciprofloxacin-resistant strains using E-test and Vitek-1 automated system. RESULTS: A total of 25,953 samples of blood culture yielded 431 Salmonella enterica serotype Typhi and 198 serotype Paratyphi A isolates. Twenty-two isolates of serotype Typhi were resistant to ciprofloxacin, while two isolates of Typhi and two Paratyphi A were intermediately susceptible to ciprofloxacin. Ciprofloxacin resistance is 5.6% (24 isolates) among Salmonella enterica serotype Typhi. Ampicillin, chloramphenicol and co-trimoxazole resistance in Salmonella enterica serotype Typhi appears to have decreased to 14.9% (64/431) in comparison to the 27% (55/205) during 2003. All isolates were sensitive to ceftriaxone. CONCLUSIONS: Ciprofloxacin can no longer be considered as the drug of choice in treating Salmonella infections. While first-line antimicrobials may still have a role to play in the treatment of enteric fever, ceftriaxone remains the sole defence against ciprofloxacin-resistant Salmonella infections.

Low-level quinolone-resistance in multi-drug resistant typhoid

To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant [MDR] typhoid using nalidixic acid screening disc. Descriptive study. Armed Forces Institute of Pathology, Rawalpindi, from January 2005 to December 2005. Blood was obtained from suspected cases of typhoid fever and cultured in to BacT/ALERT. The positive blood cultures bottles were subcultured. The isolates were identified by colony morphology and biochemical tests using API-20E galleries. Susceptibility testing of isolates was done by modified Kirby-Bauer disc diffusion method on Muellar Hinton Agar. For the isolates, which were resistant to nalidixic acid by disc diffusion method, Minimal Inhibitory Concentrations [MICs] of ciprofloxacin and nalidixic acid were determined by using the E-test strips. Disc diffusion susceptibility tests and MICs were interpreted according to the guidelines provided by National Committee for Control Laboratory Standard [NCCLS]. A total of 21[65.5%] out of 32 isolates of Salmonellae were nalidixic acid-resistant by disk diffusion method. All the nalidixic acid-resistant isolates by disc diffusion method were confirmed by MICs for both ciprofloxacin and nalidixic acid. All the nalidixic acid-resistant isolates had a ciprofloxacin MIC of 0.25-1Mu g/ml [reduced susceptibility] and nalidixic acid MICs = 32 Mu g [resistant]. Out of all Salmonella isolates, 24 [75%] were found to be MDR, and all were S. typhi. Low-level quinolone-resistance in typhoid was high in this small series. Screening for nalidixic acid resistance with a 30 Mu g nalidixic acid disk is a reliable and cost-effective method to detect low-level fluoroquinolone resistance, especially in the developing countries

Current pattern of enteric fever: a prospective clinical and microbiological study.

A prospective clinical and microbiological study was conducted in 145 blood culture positive cases of enteric fever below the age of 18 years over a period of eleven months (June 2004 to April 2005). It aimed to study the clinical profile, the relative magnitude of enteric fever in children, especially in those below the age of two years and to determine the current antibiotic sensitivity pattern of Salmonella typhi and S paratyphi. Enteric fever is a significant problem in the preschool years. Sixty-five per cent of cases were in the age group of 2 to 9 years, 27% in 0-5 years and 13% in age group 0-2 years. Ninety-two per cent of the cases were caused by S typhi. Paratyphoid fever is less common (8%), when occurs is caused by S paratyphi A. In-vitro sensitivity, using the Bauer-Kirby agar disc diffusion method, to ceftriaxone was 99%, cefixime-99%, cefotaxime-99%, cefpodoxime-72%, cefoperazone-93%, among quinolones, ciprofloxacin-95%, ofloxacin-83%, norfloxacin-79%. Sensitivity to the originally used antibiotics is reappearing: Ampicillin-87%, amoxicillin-89%, trimethoprim-sulfamethoxazole-76%, chloramphenicol-86%. Among other drugs, sensitivity to imepenam-100%, azithromycin-49%, aztreonam-65%, amikacin-98%. Nalidixic acid resistance is very high ie, 88%.

Antibiotic resistance of Salmonella enterica serovar Paratyphi A in India: emerging and reemerging problem.

BACKGROUND: Antibiotic resistance pattern and R-plasmid of Salmonella enterica serovar Paratyphi A isolates from Kolkata, India are not well documented. AIMS: To determine the trend of antibiotic resistance of S. paratyphi A isolates. SETTINGS AND DESIGN: A retrospective study was carried out using blood culture isolates of S. paratyphi A (1991 to 2005) obtained from patients of enteric fever from Asansol and Kolkata and its suburbs (India). MATERIALS AND METHODS: Antibiotic susceptibility pattern, using seven antibiotics, for the isolates was determined following agar dilution and disk diffusion methods. Transferability of multidrug resistance to ampicillin (Am), chloramphenicol (Chl), cotrimoxazole (Cot) and tetracycline (Tet) among the isolates was determined by in vitro conjugation. The multi-drug resistant (MDR) and antibiotic susceptible S. paratyphi A strains and the trans-conjugants were screened for the presence of plasmid. STATISTICAL ANALYSIS USED: The t test was used to compare the difference between mean minimum inhibitory concentration values of ciprofloxacin (Cp) for nalidixic acid (Nx)-resistant and Nalidixic acid (Nx)-susceptible isolates. RESULTS: Among 13 outbreak causing isolates in 1991, 9 (69.23%) showed AmChlCotTet-resistance, while 4 (30.77%) Cot-resistance only. During 1992-1994, all 13 isolates were susceptible to Am, Chl, Cot and Tet. During 1995-2005, isolates demonstrated different resistance patterns and emergence of nalidixic acid (Nx)-resistance. A transferable plasmid conferring AmChlCotTet-resistance was detected among MDR isolates. All the isolates were susceptible to ceftriaxone (Ctx) and ciprofloxacin (Cp). Association between Nalidixic acid (Nx)-resistance and reduced susceptibility to ciprofloxacin (Cp) among 59 S. paratyphi A isolates was noticed (P < 0.001). CONCLUSION: Vigilance for R-plasmid and surveillance of antibiotic susceptibility among S. paratyphi A isolates in and around Kolkata, India, are mandatory in order to combat antibiotic resistance of the isolates in this part of the world.

Treatment of enteric fever in children on the basis of current trends of antimicrobial susceptibility of Salmonella enterica serovar typhi and paratyphi A.

PURPOSE: Recent reports indicate decreased susceptibility of S. typhi to fluoroquinolones, especially ciprofloxacin. Chloramphenicol has been suggested as first line therapy of enteric fever in many studies. This is a prospective study that describes the trends of antimicrobial susceptibility of S. typhi and S. paratyphi A causing bacteraemia in children and reports therapeutic failure to ciprofloxacin and evaluates the possible use of chloramphenicol, ampicillin, ciprofloxacin and third generation cephalosporins as first line therapy in the treatment of enteric fever in children. METHODS: The present study was conducted from April 2004 to March 2005 in a superspeciality children hospital at New Delhi. A total of 56 S. typhi and five S. paratyphi A isolates were obtained among the 673 blood cultures performed. Antimicrobial testing was done using disk diffusion technique (NCCLS method) for 13 antimicrobials and MICs were calculated for ampicillin, ciprofloxacin, chloramphenicol and cefotaxime. Analysis of data was done using WHONET software. RESULTS: All 56 isolates of S. typhi were sensitive to amoxycillin+clavulanate, gentamicin, cefixime, cefotaxime and ceftazidime. Multidrug resistance (MDR, resistance to three drugs) was seen in 22 cases (39%) and resistance to five drugs was seen in 12 cases (21%). Only two isolates were resistant to chloramphenicol (3%). MIC 90 for ampicillin, chloramphenicol, ciprofloxacin and cefotaxime were 1.0 microg/ml, 4.0 microg/ml, 64 microg/ml and 0.125 microg/ml respectively. All S. paratyphi A isolates were sensitive to ampicillin and chloramphenicol and resistant to nalidixic acid. MIC distribution data for chloramphenicol revealed elevated MIC but still in susceptible range. CONCLUSIONS: There is an urgent need for further clinical studies to evaluate response to chloramphenicol in such cases. Antimicrobial susceptibility data and MIC distribution favour use of ampicillin as a drug of choice for the treatment of enteric fever. Third generation cephalosporins are also useful but their use should be restricted for complicated cases.

Enteric fever caused by Salmonella isolates with decreased susceptibility to ciprofloxacin.

With emerging drug resistance, ciprofloxacin became the frontline antibiotic against Salmonella strains causing enteric fevers worldwide. However, strains with decreased susceptibility to flouroquinolones have recently emerged as a problem in our region. Such strains are not detected by the routine disc diffusion method unless a nalidixic acid disc is also used. They are, however, important clinically since they show poor clinical responses and have higher faecal carriage rates following treatment with fluoroquinolones in usual doses. We report the first two cases of such strains in Sri Lanka, both acquired locally. We recommend the routine use of a nalidixic acid disc in sensitivity testing of Salmonella species, causing enteric fever in laboratories not determining minimum inhibitory concentrations (MICs) for fluoroquinolones in order to detect such strains, so that appropriate clinical decisions regarding antibiotic therapy can be made.

Antimicrobial susceptibility, phage typing and plasmid profile of salmonella enterica serotype paratyphi A strains isolated in Kuwait

To determine the antimicrobial susceptibility, phage type and plasmid profile pattern of Salmonella enterica serotype paratyphi A strains isolated in Kuwait. Material and From January 1995 to December 1999, 106 strains of S. enterica serotype paratyphi A isolated from an equal number of cases of enteric fever, attending the Infectious Disease and Mubarak Al-Kabeer Hospitals in Kuwait were investigated. The isolates were tested for antimicrobial susceptibility to 8 commonly used antimicrobial agents. Their phage type and plasmid profile patterns were determined using an international set of phages and Qiagen plasmid mini kit, respectively. All of the isolates were susceptible to ciprofloxacin, cefuroxime, ceftazidime, piperacillin and co-trimoxazole. One hundred isolates were susceptible to ampicillin, 99 to chloramphenicol and 98 to tetracycline. None of the isolates was multidrug resistant. Sixty-six% of the isolates were phage type I, 27.4% phage type II and 6.6% were untypable. All phage type I and untypable strains had 3 plasmids of 2.2, 5 and 20 kb, whereas phage type II strains had only 1 plasmid of 20 kb. The findings indicate that while all of the isolates of the S. enterica serotype paratyphi A were susceptible to 4 of the drugs tested, some were resistant to ampicillin, chloramphenicol or tetracycline, thereby indicating the need for continued surveillance and monitoring of antimicrobial susceptibility of these isolates

Sensitivity pattern of Salmonella serotypes in Northern India

BACKGROUND: Enteric fever continues to be a major public health problem, especially in the developing countries of the tropics. We determined the incidence of Salmonella bloodstream infections and their antimicrobial resistance patterns from May to August in the years 1997-2001 in Haryana, a large state of India. The minimum inhibitory concentration (MIC) was also determined for 60 isolates of S. typhi to various commonly used antimicrobial agents. MATERIAL AND METHODS: Blood cultures of 6,956 patients (PUO/septicemia) were processed by standard procedures and the Salmonella spp. isolates were identified with specific antisera and with standard biochemical tests. Antimicrobial susceptibilities were determined by Stokes disc diffusion method. The MIC of 60 randomly isolated strains of S. typhi was determined by agar dilution method using Mueller Hinton Agar medium. RESULTS: Isolation rates of Salmonella spp. increased in 2000 and 2001. Multidrug resistance (MDR) in S. typhi had increased while in S. paratyphi it had decreased markedly. Ninety per cent chloramphenicol sensitivity was seen in S. typhi by MIC method. There was a decrease in the susceptibility to ciprofloxacin of S. typhi with MIC showing an upward trend. All S. typhi tested were sensitive to third generation cephalosporins and aminoglycosides with MIC well below the breakpoint. DISCUSSION: Our study indicates that MDR in S. typhi is on the rise in our area. There is also re-emergence of chloramphenicol sensitivity. Rising MIC values of ciprofloxacin may lead to prolonged treatment, delayed recovery or pose treatment failure. Thus, sensitivity pattern of causative organism must be sought before instituting appropriate therapy to prevent further emergence of drug resistance.

Role of a large plasmid in mediation of multiple drug resistance in Salmonella typhi and paratyphi A in Bangladesh.

From 405 patients of suspected typhoid fever, 94 Salmonella typhi and 17 Salmonella paratyphi A, were isolated from blood and/or stool at the Institute of Postgraduate Medicine and Research, Dhaka during March 1992 to February 1993. Forty seven percent of the isolates were resistant to multiple drugs which included amoxicillin, ampicillin, chloramphenicol and co-trimoxazole. A large plasmid of 140 MDa was isolated from 73% of multidrug resistant (MDR) strains. However, no plasmid was isolated from any of the strains sensitive to above mentioned antibiotics. Majority of MDR Salmonella transferred resistance to E. coli K-12 (Lac+, F-, NxR.) by conjugation method. The transconjugants were similarly resistant to multiple drugs. All Salmonella were sensitive to ciprofloxacin and ceftriaxone.

Septicemias por salmonella en un recién nacido: caso clínico / Septicemia by salmonella in a newborn: clinical case

Un recién nacido, hijo de una madre infectada con salmonella paratyphi B, evoluciona en el período neonatal inmediato, con una sepsis por salmonella paratyphi B. El contagio ocurre en el período intrauterino. La sepsis se confirma con hemocultivos (+) en la madre y el hijo al mismo germen