Extensively drug-resistant typhoid fever in Pakistan

Antibiotic Resistance in Salmonella typhi Strains Isolated From Patients in Pakistan: A Hospital Database Study

BACKGROUND

The surge in antibiotic-resistant Salmonella enterica serotype Typhi strains has led to heightened morbidity, mortality, and treatment expenses. This study aims to assess the resistance patterns of Salmonella Typhi to diverse antibiotics among patients seeking care at a tertiary hospital in Pakistan.

METHODS

A database from a tertiary care hospital in Pakistan was reviewed, and data on blood cultures that isolated Salmonella enterica serotype Typhi were collected. Data were collected and analyzed using Microsoft Excel (Microsoft Corporation, USA) and IBM SPSS software (IBM Corp., Armonk, NY).

RESULTS

Demographic information of the selected data was retrieved from the hospital database, and the results showed that 63.7% were male, 36.1% were female, and 0.2% were categorized as neutered. Regarding antibiotic resistance, ampicillin exhibited the highest resistance rate (91.50%), while meropenem demonstrated the lowest (3.00%). Antibiotic sensitivity patterns also varied across different age groups, although statistical analysis indicated no significant differences. Significant associations were found between antibiotic resistance and comorbidities, as well as previous antibiotic use.

CONCLUSION

 Salmonella enterica serotype Typhi showed a high resistance to ampicillin and fluoroquinolones, such as ciprofloxacin. The emergence of resistance and decreased sensitivity to current first-line antibiotics necessitates a shift towards alternative options, such as third-generation cephalosporins, azithromycin, and newer antibiotics like meropenem.

Antimicrobial resistant strains of Salmonella typhi: The role of illicit antibiotics sales, misuse, and self-medication practices in Pakistan

Typhoid fever, caused by the bacterium Salmonella typhi, is an often-fatal illness prevalent in Africa and South Asia. The illness has seen an alarming rise in multi-drug-resistant (MDR) and extensive drug-resistant (XDR) strains, particularly in Pakistan. The MDR strain links to the H58 haplotype, and its XDR variant exhibits fluoroquinolone resistance due to an IncY plasmid. The increasing prevalence of these resistant strains is concerning, given the global antimicrobial resistance (AMR) issue. Causes include misuse of antibiotics in self-limiting infections and an unregulated drug market. Pakistan's Sindh province first reported the XDR typhoid strain, highlighting the urgent need to investigate the relationship between AMR development and external factors. This narrative review intends to scrutinize the state of AMR in Pakistan, considering illicit drug sales, healthcare worker education gaps, and self-medication behaviors.

Unlocking the Potential of Genomic Data to Inform Typhoid Fever Control Policy: Supportive Resources for Genomic Data Generation, Analysis, and Visualization

The global response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic demonstrated the value of timely and open sharing of genomic data with standardized metadata to facilitate monitoring of the emergence and spread of new variants. Here, we make the case for the value of Salmonella Typhi (S. Typhi) genomic data and demonstrate the utility of freely available platforms and services that support the generation, analysis, and visualization of S. Typhi genomic data on the African continent and more broadly by introducing the Africa Centres for Disease Control and Prevention's Pathogen Genomics Initiative, SEQAFRICA, Typhi Pathogenwatch, TyphiNET, and the Global Typhoid Genomics Consortium.

Molecular Characterization of Extensively Drug Resistant Salmonella Enterica Serovar Typhi Clinical Isolates from Lahore, Pakistan

Background

The emergence of extensively drug-resistant (XDR) typhoid in Pakistan has endangered the treatment options available to manage this infection. Third generation cephalosporin were the empiric choice to treat typhoid fever in Pakistan, but acquisition of ESBLs have knocked them out of the arsenal. The current empiric choice is azithromycin which is vulnerable to resistance too. This study aimed to assess the burden of XDR typhoid and the frequency of resistance determinants in blood culture samples collected from different hospitals in Lahore, Pakistan.

Methods

A total of 835 blood cultures were collected from different tertiary care hospitals in Lahore during January 2019 to December 2021. Among 835 blood cultures, 389 Salmonella Typhi were identified, and 150 were XDR S. Typhi (resistant to all recommended antibiotics). Antibiotics resistance genes of the first-line drugs (bla_TEM-1, catA1, sul1, and dhfR7) and second line drugs (gyrB, gyrA, qnrS, ParC and ParE) were investigated among XDR S. Typhi. There were different CTX-M genes isolated using the specific primers, bla_CTX-M-U, bla_CTX-M-1, bla_CTX-M-15, bla_CTX-M-2, bla_CTX-M-8 and bla_CTX-M-9.

Results

Antibiotic resistant genes of the first-line drugs were isolated with different frequency, bla_TEM-1 (72.6%), catA1 (86.6%), sul1 (70%), and dhfR7 (56%). Antibiotics resistance genes of second-line drugs were isolated as: gyrB (60%), gyrA (49.3%), qnrS (32.6%), parC (44%) and parE (28%). Among CTX-M genes, bla_CTX-M-U (63.3%) was the most frequent followed by bla_CTX-M-15 (39.3%) and bla_CTX-M-1 (26%).

Conclusion

Our study concluded that XDR isolates circulating in Pakistan have acquired first-line and second-line antibiotic resistant genes quite successfully along with CTX-M genes (ESBLs) rendering them resistant to the third generation cephalosporins as well. Emergence of azithromycin resistance in XDR S. Typhi which is currently used as an empiric treatment option is worrisome and needs to be monitored carefully in endemic countries like Pakistan.

Understanding the Mechanism of Antimicrobial Resistance and Pathogenesis of Salmonella enterica Serovar Typhi

Salmonella enterica serovar Typhi (S. Typhi) is a Gram-negative pathogen that causes typhoid fever in humans. Though many serotypes of Salmonella spp. are capable of causing disease in both humans and animals alike, S. Typhi and S. Paratyphi are common in human hosts only. The global burden of typhoid fever is attributable to more than 27 million cases each year and approximately 200,000 deaths worldwide, with many regions such as Africa, South and Southeast Asia being the most affected in the world. The pathogen is able to cause disease in hosts by evading defense systems, adhesion to epithelial cells, and survival in host cells in the presence of several virulence factors, mediated by virulence plasmids and genes clustered in distinct regions known as Salmonella pathogenicity islands (SPIs). These factors, coupled with plasmid-mediated antimicrobial resistance genes, enable the bacterium to become resistant to various broad-spectrum antibiotics used in the treatment of typhoid fever and other infections caused by Salmonella spp. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains in many countries of the world has raised great concern over the rise of antibiotic resistance in pathogens such as S. Typhi. In order to identify the key virulence factors involved in S. Typhi pathogenesis and infection, this review delves into various mechanisms of virulence, pathogenicity, and antimicrobial resistance to reinforce efficacious disease management.

Exploring Knowledge of Antibiotic Use, Resistance, and Stewardship Programs among Pharmacy Technicians Serving in Ambulatory Care Settings in Pakistan and the Implications

Antimicrobial resistance (AMR) is a leading global health threat, increasing morbidity, mortality, and costs, with excessive and irrational use of antimicrobials contributing to the development of AMR. Consequently, the aims of this study were to evaluate the understanding of antibiotic use, AMR, and antimicrobial stewardship programs (ASPs) among pharmacy technicians serving in ambulatory healthcare settings in Pakistan. A cross-sectional survey was conducted among pharmacy technicians serving in 144 ambulatory care settings in seven districts of Punjab province using a validated questionnaire. Overall, 376 technicians completed the survey (85.8% response rate). The majority were men (89.1%), aged 25−35 years (45.1%), serving in emergency departments (43.9%) and filling 31−60 prescriptions per day (37.5%). Most (79.5%) knew that antibiotics were one of the most frequently prescribed drug classes, while 59.8% believed antibiotics for common colds did not speed up recovery. Inadequate duration (59.6%) and inadequate dosages (57.7%) of antibiotic therapy were reported as the leading causes of AMR. Terms including ‘superbugs’, ‘multidrug resistance’, and ‘extensively drug resistance’ were known to 42.0%, 25.3%, and 20.7% of participants, respectively; however, <10% knew about ASPs, including their core elements and purpose. Our study revealed that pharmacy technicians have adequate awareness of antibiotic use but are currently unaware of AMR and ASPs, which is a concern.

Immunological characterization of chitosan adjuvanted outer membrane proteins of Salmonella enterica serovar Typhi as multi-epitope typhoid vaccine candidate

BACKGROUND

Outer membrane proteins (OMPs) of Gram-negative bacteria have been known as potential vaccine targets due to their antigenic properties and host specificity. Here, we focused on the exploration of the immunogenic potential and protective efficacy of total OMPs of Salmonella enterica serovar Typhi due to their multi epitope properties, adjuvanted with nanoporous chitosan particles (NPCPs). The study was designed to extrapolate an effective, low cost prophylactic approach for typhoid fever being getting uncontrolled in Pakistan due to emergence of extensively drug resistant (XDR) strains.

METHODS & RESULTS

The OMPs of two S. Typhi variants (with and without Vi capsule) alone and with nanoporous chitosan particles as adjuvant were comparatively analyzed for immunogenic potential in mice. Adaptive immunity was evaluated by ELISA and relative quantification of cytokine gene expression (IL4, IL6, IL9, IL17, IL10, TNF, INF and PPIA as house keeping gene) using RT-qPCR. Statistical analysis was done using Welch's test. The protection was recorded by challenging the immunized mice with 50% ×LD50 of S. Typhi. The Vi + ve-OMPs of S. Typhi showed the most promising results by ELISA and significantly high expression of IL-6, IL-10 and IL-17 and 92.5% protective efficacy with no detectable side effects.

CONCLUSION

We can conclude that the OMPs of Vi + ve S. Typhi are the most promising candidates for future typhoid vaccines because of cost effective preparation without expensive purification steps and multi-epitope properties. Chitosan adjuvant may have applications for oral protein based vaccines but found less effective in injectable preparations.

Prevention of typhoid by Vi conjugate vaccine and achievable improvements in household WASH: Evidence from a cluster-randomized trial in Dhaka, Bangladesh

BACKGROUND

Typhoid fever contributes to approximately 135,000 deaths annually. Achievable improvements in household water-hygiene-sanitation (WASH) combined with vaccination using typhoid conjugate vaccines (TCVs) may be an effective preventive strategy. However, little is known about how improved WASH and vaccination interact to lower the risk of typhoid.

METHODS

61,654 urban Bangladeshi children aged 9 months to <16 years, residing in 150 clusters with a baseline population of 205,760 residents, were randomized 1: 1 by cluster to Vi-tetanus toxoid TCV or Japanese Encephalitis (JE) vaccine. Surveillance for blood culture-confirmed typhoid fever was conducted over two years. Existing household WASH status was assessed at baseline as Better or Not Better using previously validated criteria. The reduction in typhoid risk among all residents associated with living in TCV clusters, Better WASH households, or both was evaluated using mixed-effects Poisson regression models.

RESULTS

The adjusted reduced risk of typhoid among all residents living in the clusters assigned to TCV was 55% (95% confidence interval (CI): 43%,65%; p < 0.001), and that of living in Better WASH households, regardless of cluster, was 37% (95%CI: 24%,48%; p < 0.001). The highest risk of typhoid was observed in persons living in households with Not Better WASH in the JE clusters. In comparison with these persons, those living in households with Better WASH in the TCV clusters had an adjusted reduced risk of 71% (95%CI: 59%, 80%; p < 0.001).

CONCLUSION

Implementation of TCV programs combined with achievable and culturally acceptable household WASH practices were independently associated with a significant reduction in typhoid risk.

Immune persistence and response to booster dose of Vi-DT vaccine at 27.5 months post-first dose

Vaccination with typhoid conjugate vaccines (TCV) is a major part of typhoid prevention. However, little is known about long-term immune persistence following vaccination with TCVs. In this phase-2, randomized double-blind trial (NCT03527355), 285 children aged 6–23 months were randomized to one of three groups: (1) the group that received a first dose of Vi polysaccharide conjugated to diphtheria-toxoid (Vi-DT) vaccine followed by an “early booster” at 24 weeks, (2) the group that which received a first dose of Vi-DT followed by a “late booster” at 96 or 110 weeks, and (3) comparator group. Safety and immunogenicity of anti-Vi IgG GMTs were assessed at weeks 0, 4, 24, 28, 60, 96, 110, and 114 since the first dose. Here, we describe persistence of immune responses at weeks 60, 96, 110, and 114 post first dose. The anti-Vi IgG seroconversion rate after 27.5 months of follow-up was 88.16% (95% CI: 79.00, 93.64) in late-booster and 94.76% (95% CI: 86.91, 97.88) in early booster Vi-DT groups (p = 0.081). Whereas anti-Vi IgG GMTs were significantly higher in the early booster group (11.95 [95% CI: 9.65, 14.81]) than prebooster GMTs in the late booster group (5.50 [95% CI: 4.44, 6.80], p < 0.0001). GMT in the late booster group significantly increased to 351.76 (95% CI: 265.01, 466.93) (p < 0.0001) when measured 4 weeks after they received their “late-booster” shot. In conclusion, late booster dosing with Vi-DT at 27.5 months post first dose was safe and elicited robust anti-Vi IgG immune responses. Anti-Vi IgG seroconversion rates were persistently comparable in early and late-booster Vi-DT groups.

Antimicrobial Resistance in Salmonella Typhi Isolated From a Referral Hospital of Kathmandu, Nepal

Purpose:

The morbidity and mortality due to typhoid fever can be significantly reduced with the use of effective antibiotics. At present, fluoroquinolones, third generation cephalosporins, and azithromycin are widely used to treat typhoid fever. However, changing antibiotic susceptibility among Salmonella Typhi and Salmonella Paratyphi poses a particular challenge to the therapeutic management of enteric fever. The objective of this study was to assess the antibiotic susceptibility pattern of Salmonella Typhi isolates.

Patients and Methods:

A total of 706 blood specimens were collected from febrile patients attending the outpatient department of Kathmandu Model Hospital during June to September, 2018. The antibiotic susceptibility testing for 11 different antibiotics (nalidixic acid, ciprofloxacin, ofloxacin, levofloxacin, cefixime, ceftriaxone, cefotaxime, azithromycin, cotrimoxazole, chloramphenicol, and amoxicillin) was performed by disk diffusion method. Furthermore, minimum inhibitory concentration (MIC) values of ciprofloxacin, ofloxacin, and azithromycin were determined by agar dilution method. Mutation at gyrA ser83 associated with reduced susceptibility to fluoroquinolones was determined by PCR-RFLP.

Results:

Out of 706 blood samples, 6.94% (n = 49) were culture positive for Salmonella enterica (S. Typhi, n = 46). It was revealed that 97.8% S. Typhi isolates were susceptible to conventional first-line antibiotics (ampicillin, chloramphenicol, and cotrimoxazole), 97.3% to cephalosporins and 95.7% to azithromycin. S. Typhi were either resistant or intermediately susceptible to fluoroquinolones: 97.8% to ciprofloxacin, 91.3% to ofloxacin, and 89.1% to levofloxacin. The MIC of ciprofloxacin, ofloxacin, and azithromycin for S. Typhi ranged from 0.008 to 32, 0.03 to 16, and 2 to 8 μg/mL, respectively. Out of 46 S. Typhi isolates, 44 (95.65%) had gyrA ser83 mutation.

Conclusion:

Fluoroquinolones have poor activity against Salmonella Typhi. The trends of increasing azithromycin MIC value among S. Typhi might limit its use for the treatment of typhoid fever. Effectiveness of conventional first-line antibiotics in vitro suggests considering their clinical use after large-scale studies.

Emerging Trends of Multidrug-Resistant (MDR) and Extensively Drug-Resistant (XDR) Salmonella Typhi in a Tertiary Care Hospital of Lahore, Pakistan

Salmonella Typhi is a Gram-negative pathogen that causes typhoid fever in humans. The use of antibiotics to treat typhoid has considerably mitigated its fatality risk, but rising multidrug-resistant (MDR) and extensively drug-resistant (XDR) resistance in Pakistan threatens effective treatment. This study determined the prevalence of MDR and XDR S. Typhi at a local hospital in Lahore. Blood samples (n = 3000) were obtained and processed for bacterial identification. Antibiotic susceptibility test was performed using VITEK^® 2 Compound 30 System. Statistical data analysis was performed using a Mann–Whitney U and Kruskal–Wallis H test, respectively. The results revealed 600 positive cultures, of which the majority were found to be XDR S. Typhi (46.1%) and MDR S. Typhi (24.5%) strains. The disease burden of resistant Salmonella strains was greater in males (60.67%) than females (39.33%), with the most affected age group being 0–10 years old (70.4 %). In both the outpatient department (OPD) and general ward, the prevalence of XDR S. Typhi cases was found to be alarmingly high (48.24%), followed by MDR S. Typhi (25.04 %). The results of the statistical analysis demonstrated that the incidence of resistance in MDR and XDR S. Typhi strains was not affected by the age as well as the gender of patients (p > 0.05). The occurrence of resistant strains against four tested antibiotics (azithromycin, ciprofloxacin, imipenem, and meropenem) was found to be similar in different wards and among hospitalized and OPD patients (p > 0.05). Maximum resistance was observed against chloramphenicol and ampicillin in the OPD and pediatric ward. Piperacillin/Tazobactam was observed to be the most effective antibiotic, followed by co-amoxiclav (p < 0.001). This study is effective in validating the existence of MDR and XDR S. Typhi in Lahore, where stringent methods should be applied for controlling its spread.

Antibiotic consumption among hospitalized neonates and children in Punjab province, Pakistan

BACKGROUND

Periodic surveillance of antibiotic consumption in the form of point prevalence studies is a quick and robust methodology to evaluate prescribing trends in hospitals. The current study was undertaken to document antibiotic consumption among neonates and children from hospitals in Pakistan.

METHODS

This large multicenter study using the World Health Organization standardized methodology and AWaRe (Access, Watch, and Reserve) classification examined antibiotic consumption for suspected bacterial infection among neonates and children admitted hospitals in Punjab, Pakistan.

RESULTS

A total of 708 beds of children wards of the 16 health facilities were examined. Almost all (97%) hospitalized children were prescribed antibiotics on the day of the assessment with 2.6 antibiotics per patient. The three most common indications were respiratory tract infections (31.58%), sepsis (26.52%), and prophylaxis for medical problems (10.30%). The three most frequently prescribed antibiotics were ceftriaxone (24.2%), amikacin (23.2%), and ampicillin (16.7%). Almost half of the antibiotics were prescribed from the 'Access' (49.5%) and 'Watch' (45.5%) categories under the AWaRe classification. However, no antimicrobial was prescribed from the 'Reserved' category.

CONCLUSIONS

Our findings indicate that empirical antimicrobials use among hospitalized children is highly prevalent in Pakistan. The utilization of 'Watch' category of antimicrobials is frequent, stressing immediate action.

Wastewater based environmental surveillance of toxigenic Vibrio cholerae in Pakistan

BACKGROUND

Pakistan has been experiencing intervals of sporadic cases and localized outbreaks in the last two decades. No proper study has been carried out in order to find out the environmental burden of toxigenic V. cholerae as well as how temporal and environmental factors associated in driving cholera across the country.

METHODS

We tested waste water samples from designated national environment surveillance sites in Pakistan with RT-PCR assay. Multistage sampling technique were utilized for samples collection and for effective sample processing Bag-Mediated Filtration system, were employed. Results were analysed by district and month wise to understand the geographic distribution and identify the seasonal pattern of V. cholera detection in Pakistan.

RESULTS

Between May 2019, and February 2020, we obtained and screened 160 samples in 12 districts across Pakistan. Out of 16 sentinel environmental surveillance sites, 15 sites showed positive results against cholera toxigenic gene with mostly lower CT value (mean, 34±2) and have significant difference (p < 0.05). The highest number of positive samples were collected from Sindh in month of November, then in June it is circulating in different districts of Pakistan including four Provinces respectively.

CONCLUSION

V. cholera detection do not follow a clear seasonal pattern. However, the poor sanitation problems or temperature and rainfall may potentially influence the frequency and duration of cholera across the country. Occurrence of toxigenic V. cholerae in the environment samples showed that cholera is endemic, which is an alarming for a potential future cholera outbreaks in the country.

A Case Report of Extensively Drug Resistant Typhoid in Karachi, Pakistan: A Major Health Concern to Curb the Outbreak

The disease burden of extensively drug resistant typhoid in developing countries is a major emerging issue that cannot be ignored. Since its emergence from multidrug strains, the majority of typhoid cases in Karachi, Pakistan, have been extensively drug resistant, mostly infecting younger patients. In the study, the authors analysed one such case in an adolescent male and discussed how, by the implementation of national health policies, the spread of these infectious diseases could be prevented and the overall burden on the healthcare system decreased in areas with already limited resources.

Infections in immunosuppressed travellers with autoimmune inflammatory diseases-a narrative review and advice for clinical practice

The management of autoimmune, inflammatory diseases has been revolutionized by biologic therapies. A beneficial consequence of better disease control is that more patients are well enough to travel the world. There is now a class of traveller, the significantly immunosuppressed person with autoimmune disease, with specific risks and requirements. This review introduces the concept of the pre-travel risk assessment and discusses the major vaccine-preventable and non-vaccine-preventable travel-associated infections. The challenges and controversies around vaccination and immunosuppression are reviewed with advice for clinical practice.

A rare case of extensively drug-resistant Salmonella typhi meningitis in a 9-year old: a case report

Meningitis caused by Salmonella typhi is rare and is generally seen in infants. We report a case of a 9-year-old boy with extensively drug-resistant S. typhi meningitis. The patient was diagnosed using a culture sensitivity test and successfully treated with meropenem. Culture sensitivity may be included in routine testing for the diagnosis of S. typhi especially in developing countries due to high burden of disease and emergence of drug resistance.

Progress on the national action plan of Pakistan on antimicrobial resistance (AMR): a narrative review and the implications

Introduction: The emergence of antimicrobial resistance (AMR) is a threat to public health. In 2015, the World Health Organization (WHO) introduced a global action plan to tackle AMR in the World Health Assembly. Pakistan's national action plan (NAP) for AMR was released in May 2017 by the Ministry of National Health Services. Based on the NAP, strategies have been initiated on a national and provincial scale in Pakistan.Areas covered: This narrative review of the five components of the Pakistan NAP has been undertaken to discuss some of the challenges in implementation of the NAP for AMR in Pakistan including different opinions and views of key stakeholders, combined with suggestions on potential ways to reduce the burden of the AMR.Expert opinion: Going forward, healthcare authorities should focus on screening and monitoring of all the objectives of the NAP by establishing proper policies as well as promoting antimicrobial stewardship interventions and Infection prevention and control (IPC) practices. Overall, the comprehensive strengthening of the healthcare system is required to adequately implement the NAP, tackle continued inappropriate antimicrobial use and high AMR rates in Pakistan.

Morbidity and Mortality Associated with Typhoid Fever Among Hospitalized Patients in Hyderabad District, Pakistan, 2017-2018: Retrospective Record Review

BACKGROUND

Hyderabad, Pakistan, was the first city to witness an outbreak of extensively drug resistant (XDR) typhoid fever. The outbreak strain is resistant to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, fluoroquinolones, and third-generation cephalosporin, thus greatly limiting treatment options. However, despite over 5000 documented cases, information on mortality and morbidity has been limited.

OBJECTIVE

To address the existing knowledge gap, this study aimed to assess the morbidity and mortality associated with XDR and non-XDR Salmonella serovar Typhi infections in Pakistan.

METHODS

We reviewed the medical records of culture-confirmed typhoid cases in 5 hospitals in Hyderabad from October 1, 2016, to September 30, 2018. We recorded data on age, gender, onset of fever, physical examination, serological and microbiological test results, treatment before and during hospitalization, duration of hospitalization, complications, and deaths.

RESULTS

A total of 1452 culture-confirmed typhoid cases, including 947 (66%) XDR typhoid cases and 505 (34%) non-XDR typhoid cases, were identified. Overall, ≥1 complications were reported in 360 (38%) patients with XDR typhoid and 89 (18%) patients with non-XDR typhoid (P<.001). Ileal perforation was the most commonly reported complication in both patients with XDR typhoid (n=210, 23%) and patients with non-XDR typhoid (n=71, 14%) (P<.001). Overall, mortality was documented among 17 (1.8%) patients with XDR S Typhi infections and 3 (0.6%) patients with non-XDR S Typhi infections (P=.06).

CONCLUSIONS

As this first XDR typhoid outbreak continues to spread, the increased duration of illness before hospitalization and increased rate of complications have important implications for clinical care and medical costs and heighten the importance of prevention and control measures.

Risk Factors of Extensively Drug Resistant Typhoid Fever Among Children in Karachi: Case-Control Study

Background

Extensively drug resistant typhoid fever (XDR-TF) has been responsible for an ongoing outbreak in Pakistan, which began in November 2016.

Objective

This study aimed to determine the risk factors associated with XDR-TF.

Methods

This age- and sex-matched case-control study was conducted during May-October 2018 in Karachi. All patients with XDR-TF were identified from the laboratory-based surveillance system data. Cases included patients aged <15 years living in Karachi with culture-positive Salmonella enterica serovar Typhi with resistance to chloramphenicol, ampicillin, trimethoprim/sulfamethoxazole, fluoroquinolones, and third-generation cephalosporins. Age- and sex-matched controls included children free from the symptoms of TF, aged under 15 years, and residing in Karachi. All controls were recruited from among those who attended outpatient clinics.

Results

A total of 75 cases and 75 controls were included in this study. On univariate analysis, the odds of having XDR-TF were 13-fold higher among participants who used piped municipal water than among those who did not (odds ratio [OR] 12.6, 95% CI 4.1-38.6). The use of bore water was significantly associated with XDR-TF (OR 5.1, 95% CI 1.4-19.0). Cases were more likely to report eating French fries with sauce (OR 13.5, 95% CI 3.9-47.0) and poppadum (OR 3.4, 95% CI 1.7-6.7) from street vendors than controls. Boiling water at home was negatively associated with XDR-TF (OR 0.3, 95% CI 0.2-0.7). On multivariate analysis, 2 factors were independently associated with XDR-TF. Using piped municipal water (OR 10.3, 95% CI 3.4-30.4) and eating French fries with sauce from street vendors (OR 8.8, 95% CI 2.1-36.2) were significantly associated with an increased odds of XDR-TF.

Conclusions

Community water supply and street food eating habits were implicated in the spread of the superbug S typhi outbreak, which continues to grow in Karachi. Therefore, it is recommended to improve the community water supply to meet recommended standards and to develop a policy to improve the safety of street food. In addition, health authorities are required to conduct mass vaccination for TF among high-risk groups.

A skeleton in the closet: The implications of COVID-19 on XDR strain of typhoid in Pakistan

Extensively drug resistant typhoid fever is a major public health concern in Pakistan. During the COVID-19 pandemic, poor sanitation is leading typhoid cases to a surge and obsolete diagnostic methods are paving the way towards ir-rational pharmacotherapy. In particular, the overuse of azithromycin for the treatment of COVID-19 might impair one of the few remaining regimens against XDR. Facing COVID-19 and XDR at the same time can lead to a catastrophy, unless the government, the stakeholders and healthcare workers take joint action to improve sanitation, educate the public, vaccinate vulnerable groups and establish good diagnostic and management practices.

Vi-specific serological correlates of protection for typhoid fever

Typhoid Vi vaccines have been shown to be efficacious in children living in endemic regions; however, a widely accepted correlate of protection remains to be established. We applied a systems serology approach to identify Vi-specific serological correlates of protection using samples obtained from participants enrolled in an experimental controlled human infection study. Participants were vaccinated with Vi-tetanus toxoid conjugate (Vi-TT) or unconjugated Vi-polysaccharide (Vi-PS) vaccines and were subsequently challenged with Salmonella Typhi bacteria. Multivariate analyses identified distinct protective signatures for Vi-TT and Vi-PS vaccines in addition to shared features that predicted protection across both groups. Vi IgA quantity and avidity correlated with protection from S. Typhi infection, whereas higher fold increases in Vi IgG responses were associated with reduced disease severity. Targeted antibody-mediated functional responses, particularly neutrophil phagocytosis, were also identified as important components of the protective signature. These humoral markers could be used to evaluate and develop efficacious Vi-conjugate vaccines and assist with accelerating vaccine availability to typhoid-endemic regions.

Adherence to the Core Elements of Outpatient Antibiotic Stewardship: A Cross-Sectional Survey in the Tertiary Care Hospitals of Punjab, Pakistan

BACKGROUND

There is a growing global interest in hospital-based antibiotic stewardship programs (ASPs). Centers for Disease Control and Prevention (CDC) recommends clinicians and facilities in outpatient department (OPD) to adhere to a set of stewardship activities called the Core Elements of Outpatient Antibiotic Stewardship (CEOAS). CEOAS includes 4 core elements for OPD facilities and clinicians each, ie, commitment, action, tracking and reporting, and education and expertise.

AIM

The aim of this study was to evaluate the adherence of OPDs in tertiary care hospitals to CEOAS.

DESIGN AND SETTING

A cross-sectional study in the hospitals in Punjab, Pakistan.

METHODS

Study was reported as per STROBE guidelines. Data were collected from hospitals based on purposive sampling on the CEOAS framwork. On a summative scale, positive response to each core element worthed a score and higher the score better the adherence. Descriptive statistics was used for categorical variables while independent t-test computed group differences.

RESULTS

Fifty-three tertiary care hospitals (n=22 public, n=31 private) participated (response rate=86.9%). No hospital reported "perfect" adherence. Overall, facilities and clinicians in OPDs were moderately adherent. Subgroup analysis indicated that hospitals in public and private were poorly (4.9) and moderately (6.0) adherent to CEOAS respectively, however, private clinicians scored significantly higher in action, and tracking and reporting. Tracking and reporting of antibiotics and education of patients and clinicians emerged as top deficiency areas in facilities and clinicians respectively.

CONCLUSION

Significant gaps exist in the adherence to CEOAS. The deficiency areas highlighted in the study should be given priority in future policy shift.

Typhoid Outbreaks, 1989-2018: Implications for Prevention and Control

Typhoid fever remains an important public health problem in low- and middle-income countries, with large outbreaks reported from Africa and Asia. Although the WHO recommends typhoid vaccination for control of confirmed outbreaks, there are limited data on the epidemiologic characteristics of outbreaks to inform vaccine use in outbreak settings. We conducted a literature review for typhoid outbreaks published since 1990. We found 47 publications describing 45,215 cases in outbreaks occurring in 25 countries from 1989 through 2018. Outbreak characteristics varied considerably by WHO region, with median outbreak size ranging from 12 to 1,101 cases, median duration from 23 to 140 days, and median case fatality ratio from 0% to 1%. The largest number of outbreaks occurred in WHO Southeast Asia, 13 (28%), and African regions, 12 (26%). Among 43 outbreaks reporting a mode of disease transmission, 24 (56%) were waterborne, 17 (40%) were foodborne, and two (5%) were by direct contact transmission. Among the 34 outbreaks with antimicrobial resistance data, 11 (32%) reported Typhi non-susceptible to ciprofloxacin, 16 (47%) reported multidrug-resistant (MDR) strains, and one reported extensively drug-resistant strains. Our review showed a longer median duration of outbreaks caused by MDR strains (148 days versus 34 days for susceptible strains), although this difference was not statistically significant. Control strategies focused on water, sanitation, and food safety, with vaccine use described in only six (13%) outbreaks. As typhoid conjugate vaccines become more widely used, their potential role and impact in outbreak control warrant further evaluation.

Extensively Drug-Resistant (XDR) Typhoid: Evolution, Prevention, and Its Management

Typhoid fever is the result of a human host-restricted Salmonella enteric serotype typhi infection that causes enteric fever. Around 21 million people contract typhoid annually, with Pakistan's inhabitants at most risk amongst Asian countries where typhoid remains prevalent. Decades of indiscriminate antibiotic usage has driven the evolution of multidrug-resistant strains and more recently, extensively drug-resistant (XDR) strains of Salmonella enteric serotype typhi. Current reports of extensively drug-resistant typhoid fever outbreak in Pakistan are not only a major concern for Pakistan but also for health authorities worldwide: intercontinental transmission, spread, and replacement of native strains in neighboring countries and a major impediment to Pakistani health care management. The WHO records that there are 5274 cases of extensively drug-resistant (XDR) typhoid fever out of a total of 8188 total cases of typhoid fever reported in Pakistan. The last remaining feasible oral antibiotic that XDR typhoid remains susceptible to is azithromycin; this is a cause of major concern. Additionally, several cases of XDR typhoid fever have also been reported in patients travelling from Pakistan to the USA, UK, and Canada. This review article attempts to raise the issue of XDR typhoid with respect to its epidemiology, prevention, management, and future outlook and stresses a better understanding of antimicrobial stewardship and general surveillance of the disease. Although progress is being made to combat XDR typhoid locally, efficient, unified efforts on a national and international scale are required to contain the XDR outbreak before it is no longer manageable and leads us back to the preantibiotic era.

Drug-Resistant Salmonella typhi in Pakistan

Enteric fever (formerly typhoid fever) is a bacterial illness caused by fecal-oral transmission of Salmonella typhi or paratyphi. In early 2018, an outbreak of Salmonella typhi resistant to third-generation cephalosporins, ampicillin, ciprofloxacin, trimethroprim-sulfamethoxazole, and chloramphenicol was reported in Pakistan. This strain, termed "extensively resistant typhi," has infected more than 5000 patients in endemic areas of South Asia, as well as travelers to and from these areas, including 5 cases in the United States. We present the case of one such child who developed extensively resistant enteric fever during a recent visit to Pakistan and required broader antimicrobial treatment than typically required. Clinicians should be aware that incoming cases of enteric fever may be nonsusceptible to commonly recommended antibiotics and that extensively resistant typhi requires treatment with carbapenems such as meropenem or azithromycin.

New immunization strategies: adapting to global challenges

Immunization has made an enormous contribution to global health. Global vaccination coverage has dramatically improved and mortality rates among children due to vaccine-preventable diseases have been significantly reduced since the creation of the Expanded Programme of Immunization in 1974, the formation of Gavi, the Vaccine Alliance, in 2000, and the development of the Global Vaccine Action Plan in 2012. However, challenges remain and persisting inequities in vaccine uptake contribute to the continued occurrence and outbreaks of vaccine-preventable diseases. Inequalities in immunization coverage by geography, urban-rural, and socio-economic status jeopardize the achievement of global immunization goals and call for renewed immunization strategies. These should take into account emerging opportunities for building better immunization systems and services, as well as the development of new vaccine products and delivery technologies. Such strategies need to achieve equity in vaccination coverage across and within countries. This will require the participation of communities, a better understanding of vaccine acceptance and hesitancy, the expansion of vaccination across the life course, approaches to improve immunization in middle-income countries, enhanced use of data and possible financial and non-financial incentives. Vaccines also have an important role to play in comprehensive disease control, including the fight against antimicrobial resistance. Lessons learned from disease eradication and elimination efforts of polio, measles and maternal and neonatal tetanus are instrumental in further enhancing global immunization strategies in line with the revised goals and targets of the new Immunization Agenda 2030, which is currently being developed.

An Overview of Extensively Drug-resistant Salmonella Typhi from a Tertiary Care Hospital in Pakistan

INTRODUCTION

 Since 2016, the province of Sindh is in the limelight because of its association with the emergence and spread of extensively drug-resistant Salmonella typhi (XDR S. typhi). Although its global spread has been proven in several studies, our information regarding its countrywide existence is still insufficient. In the last four years, few cases of XDR S. typhi were identified at the Shifa International Hospital (SIH), Islamabad, Pakistan. This article aims to report demographic patterns, clinical presentations, and treatment outcome of these cases.

MATERIALS AND METHODS

 This study was conducted at SIH, Islamabad, on blood culture-proven XDR S. typhi cases from January 2015 to December 2018. The data were retrieved from the hospital's record system. Patient demographic details, clinical presentations, management, and disease outcomes were evaluated and statistical analysis was performed through IBM SPSS Statistics for Windows, version 23.0 (IBM Corp., Armonk, NY).

RESULTS

 A total of 30 blood culture-proven XDR S. typhi cases were identified and 80% (24) of them were reported in 2018. The mean age at presentation was 12.8±9.6 years. Twelve (40%) patients came from Islamabad, nine (30%) from Rawalpindi, and eight (26.6%) from Khyber Pakhtunkhwa (KPK). All patients, except one, were prescribed meropenem and azithromycin. Three patients developed complications but no mortality was documented. Over four years, these XDR S. typhi cases contributed 5.01% to the total S. typhi isolates.

CONCLUSION

This study validates the existence of XDR S. typhi all over Pakistan. It stresses upon the fact that more stringent methods should be adopted for its identification and control.

Draft genome of a macrolide resistant XDR Salmonella enterica serovar Paratyphi A strain using a shotgun sequencing approach

OBJECTIVES

Salmonella enterica serovar Paratyphi A, the causative pathogen of enteric fever, is a major public-health concern affecting millions of people around the world. We conducted whole-genome sequencing and analysis of a novel macrolide-resistant Salmonella Paratyphi A strain isolated from Karachi, Pakistan.

METHODS

Genomic DNA of Salmonella Paratyphi A strain JRCGR-AK14 was sequenced on a MiSeq platform. Read quality was evaluated and paired-end reads were assembled into contigs and scaffolds. The quality of contigs and scaffolds was evaluated and assembled contigs were annotated. Virulence genes, antimicrobial resistance genes (ARGs), tRNAs, rRNAs, coding sequences and clustered regularly interspaced short palindromic repeats (CRISPRs) were identified. ARGs and mutations in quinolone-resistance determining regions (QRDRs) were identified by Antimicrobial Resistance Identification By Assembly (ARIBA) and ResFinder. Known and unknow mutations in the QRDRs were predicted.

RESULTS

The genome of Salmonella Paratyphi A was calculated at 4529866 bp with 4381 genes and 1088 hypothetical proteins. Several putative genes coding for multidrug efflux pumps were identified. In addition, gene mutations conferring resistance to nitrofurantoin (e.g. marA, mdsC, Escherichia coli soxS), pulvomycin (e.g. H-NS, cpxA, E. coli EF-Tu) and fosfomycin (CRP, kdpE, E. coli glpT) were also identified. Several ARGs along with the mobile genetic element transposon Tn10 were also identified. It is evident from the results that diverse redundant mechanisms are involved in regulation of drug resistance in this strain.

CONCLUSION

The current findings provide valuable data for understanding the multidrug resistance and pathogenic characteristics of clinical Salmonella Paratyphi A isolates.

The Implications of Extensive Drug-resistant Typhoid Fever: A Case Report

Salmonella Typhi (S.Typhi) is the causative agent in typhoid fever. In Pakistan, an extensive drug-resistant (XDR) S.Typhi strain has emerged that is resistant to all recommended antibiotics, including third-generation cephalosporins. We report the case of a 29-year-old pregnant woman presenting with high-grade fever, lower abdominal pain, concerns of urinary burning, and increased urinary frequency lasting four days. Blood cultures confirmed XDR S. Typhi. This case highlights three important items: the emergence of the XDR typhoid strain in an unstudied community, the susceptibility of immunocompromised individuals to infectious diseases, and the role health care practitioners can play in controlling its spread regionally and globally.