Ciprofloxacin therapy for typhoid fever needs reconsideration

Clinical Characteristics and Antibiotics Sensitivity of Culture Positive Typhoid Fever Patients in Baghdad Teaching Hospital - A Single Center Study

BACKGROUND: Enteric fever caused by Salmonella Typhi is an endemic disease in Iraq. Variations in presentations make it a diagnostic challenge. If untreated or treated inappropriately then it is a serious disease with potentially life-threatening complications. The recent emergence of drug resistant strains of S. Typhi is a rising public health problem and a clinical concern to the physician. AIM: The objectives of the study were to assess and describe the patterns of antimicrobial resistance, clinical characteristics, epidemiological distribution, and complications of typhoid fever. PATIENTS AND METHODS: Fifty cases of typhoid fever (culture proven) were collected during the period from February 2019 to November 2019 in the medical wards of Baghdad Teaching Hospital. Detailed history, physical examination, and laboratory investigations were conducted and statistical analysis of the results was done, prospective observational study was conducted. RESULTS: During the study period, 50 cases of typhoid fever were documented, mean age of presentation was 30.7 ± 12.8, 60% of the cases were male gender, gastrointestinal complications were the most common (90%) followed by hematological complications (71%). Mortality of typhoid fever in our study was 2%. High percentage of resistance to third generation cephalosporins, ciprofloxacin, and azithromycin was found (96%, 56%, and 56%, respectively) while good sensitivity to trimethoprim and meropenem was found (94% and 76%, respectively). Significant association was also found between the development of typhoid fever complications and the presence of anemia, thrombocytopenia, lymphopenia, and eosinopenia. Significant association was also found between the complications and the infection with strains resistant to cephalosporins, ciprofloxacin, and azithromycin. CONCLUSIONS: There is a concerning increase in resistance toward cephalosporins, ciprofloxacin, and azithromycin while meropenem and trimethoprim are emerging as effective drugs. There was high incidence of complications found (84%).Lymphopenia, anemia, eosinopenia, and thrombocytopenia are independent risk factors for the development of complications of typhoid fever.

Antibiotic resistome of Salmonella typhi: molecular determinants for the emergence of drug resistance

Resistome is a cluster of microbial genes encoding proteins with necessary functions to resist the action of antibiotics. Resistome governs essential and separate biological functions to develop resistance against antibiotics. The widespread clinical and nonclinical uses of antibiotics over the years have combined to select antibiotic-resistant determinants and develop resistome in bacteria. At present, the emergence of drug resistance because of resistome is a significant problem faced by clinicians for the treatment of Salmonella infection. Antibiotic resistome is a dynamic and ever-expanding component in Salmonella. The foundation of resistome in Salmonella is laid long before; therefore, the antibiotic resistome of Salmonella is reviewed, discussed, and summarized. We have searched the literature using PubMed, MEDLINE, and Google Scholar with related key terms (resistome, Salmonella, antibiotics, drug resistance) and prepared this review. In this review, we summarize the status of resistance against antibiotics in S. typhi, highlight the seminal work in the resistome of S. typhi and the genes involved in the antibiotic resistance, and discuss the various methods to identify S. typhi resistome for the proactive identification of this infection and quick diagnosis of the disease.

Cephalosporin-resistant typhoid

Typhoid fever is endemic in developing countries like India. An increasing prevalence of resistance to cephalosporins and fluoroquinolones by Salmonella isolates is seen. We present an 8-month-old boy with invasive Salmonella typhi disease. Blood culture showed S. typhi sensitive to ampicillin–sulbactam and cotrimoxazole but resistant to fluoroquinolones and third-generation cephalosporins. Cerebrospinal fluid examination revealed an aseptic meningitic picture. He was treated with intravenous meropenem and azithromycin following which his condition improved. This case highlights the need for improvement in environment sanitation and hygiene combined with early vaccination against typhoid fever and antimicrobial stewardship to help reduce the emerging resistance to cephalosporins and fluoroquinolones.

Discovery of seven novel mutations of gyrB, parC and parE in Salmonella Typhi and Paratyphi strains from Jiangsu Province of China

Objective: To investigate the prevalence of Salmonella Typhi and Paratyphi resistance to quinolones and characterize the underlying mechanism in Jiangsu Province of China. Methods: Antimicrobial susceptibility testing was performed using Kirby-Bauer disc diffusion system. Quinolone resistance-determining region (QRDR), plasmid-mediated quinolone resistance (PMQR) determinant genes were detected by PCR and sequencing. Results: Out of 239 Salmonella isolates, 164 were S. Typhi and 75 were S. Paratyphi. 128 (53.6%) Salmonella isolates were resistant to nalidixic acid; 11 (4.6%) isolates to ciprofloxacin and 66 (27.6%) isolates were intermediate to ciprofloxacin. QRDR were present in 69 S. Typhi isolates, among which mutation at codon 83 (n = 45) and 133 (n = 61) predominated. In S. Paratyphi, the most common mutations were detected in gyrA at codon 83(n = 24) and parC: T57S (n = 8). Seven mutations were first reported in Salmonella isolates including gyrB: S426G, parC: D79G and parE: [S498T, E543K, V560G, I444S, Y434S]. PMQR genes including qnrD1, qnrA1, qnrB4, aac (6′)-Ib-cr4 and qnrS1 were detected in 1, 2, 3, 7 and 9 isolates, relatively. Conclusions: High resistance to quinolones in Salmonella remains a serious problem in Jiangsu, China. The presence of the novel mutations increases the complexity of quinolone-resistant genotypes and poses a threat to public health. Subject terms: Salmonella Typhi, Salmonella Paratyphi, antimicrobial resistance, QRDR, PMQR.

Estimating the burden of enteric fever in Chhattisgarh: A single-center study on culture-positive cases from a newly built tertiary care hospital

BACKGROUND

Enteric fever is the most common cause of community acquired blood stream infections in under developed and developing countries. The enteric fever is exclusive to humans and transmitted through the faeco-oral route. Though India is an endemic zone for enteric fever, the data is very scarce from Central India. The present study was undertaken to determine the prevalence of enteric fever in this region and to know the antimicrobial susceptibility pattern of the isolated typhoidal Salmonellae.

MATERIAL AND METHOD

We conducted a retrospective analysis of blood culture positive cases of enteric fever over a period of two years (December 2015 to December 2017). All blood cultures submitted for suspected enteric fever and associated symptoms were included in the study. Relevant demographic, clinical and laboratory data were analyzed.

RESULT

A total of 51 cases (3.56%) were of typhoidal Salmonella from a total of 1430 blood culture submission. Salmonella Typhi were 70.5% while Salmonella Paratyphi A were 29.5% of the total isolated Salmonellae. The most vulnerable age group was 10-19years (41.2%). The mean minimum inhibitory concentration of ciprofloxacin for Salmonella Typhi and Salmonella Paratyphi A are 1.20 and 1.97 μg/ml respectively. All the isolates were susceptible to ceftriaxone. Highest isolation was in the July - September quarter (35.3%).

CONCLUSION

There is a high prevalence of the disease which needs urgent focus on safe water, sanitation services and also to establish guidelines for empiric therapy for enteric fever.

Antimicrobial resistance and molecular subtypes of Salmonella enterica serovar Typhi isolates from Kolkata, India over a 15 years period 1998-2012

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), remains an unresolved public health problem in India. Emergence of antimicrobial resistant strains poses a great concern for typhoid treatment and influences reshaping of current S. Typhi population. We included representative S. Typhi strains (n=164) from retrospective studies, both community and hospital based, conducted at National Institute of Cholera and Enteric Diseases, Kolkata during 15 years period (1998-2012) to analyze their antimicrobial resistance (AMR) profiles, mechanism of AMR and molecular subtypes of the strains. More than 60% of the S. Typhi isolates were obtained from community based studies. During the study period, steady decline (46.4%-15.6%) in isolation of multidrug-resistant (MDR, resistant to ampicillin, chloramphenicol and co-trimoxazole) S. Typhi was noticed with parallel increase of nalidixic acid-resistant (NAL^R) strains (60.7%-93.8%) and ciprofloxacin resistant (CIP^R) strains (0%-25%). Of 53 MDR strains, 46 (86.8%) were NAL^R showing decreased ciprofloxacin susceptible (DCS) (MIC for ciprofloxacin 0.12-0.5μg/ml) phenotype. Conjugative IncHI1 (230kb) and non-conjugative non-IncHI1 (180kb) plasmids were found in 23 (43.4%) and 14 (26.4%) MDR strains respectively, plasmid was absent in 16 (30.2%) MDR strains. MDR strains with or without plasmid shared the same set of resistance genes (bla_TEM-1, catA1, sul1, sul2, strA and strB) and class 1 integron possessing dfrA7 gene cassette. Two S. Typhi strains harbored 50kb transferrable plasmids carrying dfrA15 and aadA1 gene cassettes in class 1 integron. The majority of the strains (135/164, 82.3%) belonged to H58 haplotype. Among the MDR isolates, fluoroquinolone resistant or combined resistant isolates (n=147), 127 (86.4%) were H58 and 20 (13.6%) belonged to non-H58. NAL^RS. Typhi strains with decreased susceptibility or resistance to ciprofloxacin had point mutation(s) in quinolone resistance-determining region of gyrA and parC genes. Pulsed-field gel electrophoresis showed more diversity among NAL^RS. Typhi than MDR strains. Results of this study generated information useful for better understanding of the disease epidemiology and its control in endemic settings.

The emergence and outbreak of multidrug-resistant typhoid fever in China

Typhoid fever remains a severe public health problem in developing countries. The emergence of resistant typhoid, particularly multidrug-resistant typhoid infections, highlights the necessity of monitoring the resistance characteristics of this invasive pathogen. In this study, we report a typhoid fever outbreak caused by multidrug-resistant Salmonella enterica serovar Typhi strains with an ACSSxtT pattern. Resistance genes conferring these phenotypes were harbored by a large conjugative plasmid, which increases the threat of Salmonella Typhi and thus requires close surveillance for dissemination of strains containing such genes.

Antimicrobial resistance in Salmonella enterica serovar typhi and paratyphi in South Asia-current status, issues and prospects

The human race owes a debt of gratitude to antimicrobial agents, penicillin and its successors that have saved people from tremendous pain and suffering in the last several decades. Unfortunately, this consideration is no more true, as millions of people are prone to the challenging threat of emergence of antimicrobial resistance worldwide and the menace is more distressing in developing countries. Comparable with other bacterial species, Salmonella enterica serovar Typhi (S. typhi) and Paratyphi (S. paratyphi) have been evolving multidrug resistance (MDR) against a wide array of antibiotics, including chloramphenicol, ampicillin and co-trimoxazole, and globally affecting 21 million people with 220,000 deaths each year. S. typhi and S. paratyphi infections are also endemic in South Asia and a series of antibiotics used to treat these infections, have been losing efficacy against enteric fever. Currently, quinolones are regarded as a choice to treat MDR Salmonella in these regions. Travel-related cases of enteric fever, especially from South Asian countries are the harbinger of the magnitude of MDR Salmonella in that region. Conclusively, the MDR will continue to grow and the available antimicrobial agents would become obsolete. Therefore, a radical and aggressive approach in terms of rational use of antibiotics during treating infections is essentially needed.

Profile of Culture Positive Enteric Fever from Bangalore

BACKGROUND

Enteric fever is endemic in India. The aim of this study was to analyse the clinical, laboratory, antibiotic sensitivity profile and response to antibiotics of culture positive enteric fever patients from Bangalore.

METHODS

In this retrospective study only culture positive enteric fever patients were taken and their clinical, laboratory, antibiotic sensitivity profile and the clinical response to antibiotics studied.

RESULT

Eighty one culture positive enteric fever patients were taken into the study. Presenting symptoms included fever, pain abdomen (18.5%), loose stools (25%), vomiting (33%) and headache (30%). Absolute bradycardia at admission was not found in any of our patients. Normal or low total leucocyte count was seen in 97.5%. Typhoid hepatitis was seen in 8.5%. Salmonella enterica subspecies enterica serovar typhi (S typhi) were isolated in 80% of cases; 83% of all cases showed nalidixic acid resistance. All isolates were sensitive to chloramphenicol and third generation cephalosporins. Ciprofloxacin resistance was found in 19% cases. The time to defervescence in patients treated with ceftriaxone was 4.3 days. There was no statistical difference in time to defervescence in nalidixic acid resistant and sensitive strains. Complications included gastro intestinal bleed and encephalopathy.

CONCLUSION

Prevalence of nalidixic acid resistance is high, while clinical resistance to quinolones may be higher than that found in the laboratory which requires detailed study. Chloramphenicol sensitivity has returned and nalidixic acid resistant and sensitive isolates are uniformly sensitive to third generation cephalosporins with no difference in time to defervescence.