Antimicrobial susceptibility pattern of Burkholderia cepacia complex & Stenotrophomonas maltophilia from North India: Trend over a decade (2007-2016)

Epidemiology and Antimicrobial Resistance of Stenotrophomonas maltophilia in China, 2014-2021

INTRODUCTION

Stenotrophomonas maltophilia is an opportunistic pathogen associated with various nosocomial infections and is known for its intrinsic multidrug resistance. This study aims to provide a comprehensive overview of the epidemiology and resistance patterns of S. maltophilia in China from 2014 to 2021.

METHODS

Data were extracted from the China Antimicrobial Resistance Surveillance System (CARSS) and the Blood Bacterial Resistance Investigation Collaborative System (BRICS), encompassing 1412 medical institutions across 31 provinces in China. We analyzed the prevalence of S. maltophilia in clinical isolates, focusing on specific patient populations and departments, as well as resistance profiles to recommended first-line antibiotics, including sulfamethoxazole-trimethoprim, levofloxacin, and minocycline.

RESULTS

A total of 514,768 S. maltophilia strains were analyzed. The overall prevalence of S. maltophilia among all clinical bacterial isolates remained stable at approximately 2.1%, with higher rates observed in intensive care units and elderly patients. Resistance rates to sulfamethoxazole-trimethoprim decreased from 9.8% in 2014 to 7.5% in 2021. In contrast, resistance to levofloxacin showed a slight upward trend, increasing from 8.5% in 2014 to 9.5% in 2021. Meanwhile, minocycline resistance remained low, fluctuating marginally from 2.7% in 2014 to 1.7% in 2021.

CONCLUSIONS

This study highlights the stable prevalence of S. maltophilia in clinical settings in China and the overall low resistance rates to recommended first-line antibiotics. However, alarmingly high resistance rates were observed in specific specimen types, particularly in blood cultures, suggesting that minocycline may be the only reliable therapeutic option among the six tested antibiotics for treating such infections in China. Continuous surveillance and effective infection control measures are essential to manage S. maltophilia infections, particularly in vulnerable populations. Future research should focus on measuring the true burden of these infections and monitoring the susceptibility of the newly introduced antibiotics, such as cefiderocol.

Burkholderia cepacia complex nosocomial outbreaks in India: A scoping review

Burkholderia cepacia complex (Bcc) is an opportunistic pathogen that causes severe infections in immunocompromised individuals. It is a common contaminant of medical drugs, solutions and devices used in healthcare setups. This scoping review aimed to assess Bcc outbreaks in Indian hospital settings and address a wide range of sources to improve outbreak management. As per PRISMA-ScR guidelines, electronic databases 'Embase', 'PubMed' and 'Web of Science' were searched from 1993 to September 2024 to identify studies reporting Burkholderia cepacia complex outbreaks across India. The search identified 22 outbreak reports meeting the inclusion criteria. Bacteremia was the most common presentation in twenty studies, followed by acute-onset post-operative endophthalmitis in two studies. In 14 outbreak studies, B. cepacia was the identified species, whereas five studies had Bcc; one study each had B. cenocepacia, B. multivorans and B. contaminans isolated. Most outbreaks were associated with contaminated pharmaceuticals (45.4%) and medical (18.1%) products in contrast to the environment as a source (13.6%). Multi-locus sequence typing (MLST) was employed to study clonality among isolates in six outbreaks. This review highlights that varied medical products and environmental surfaces/objects can harbour Bcc and act as potential sources of Bcc outbreaks in hospitals. Ensuring immediate identification of Bcc from clinical samples, regular sterility checks, thorough epidemiological investigations, and timely infection control and prevention measures are critical to help manage and prevent these outbreaks and the subsequent mortality.

A Five-Year Trend Analysis of Antibacterial Resistance Patterns Among Non-fermenting Gram-Negative Bacilli: A Retrospective Study From the ICU Settings of a Tertiary Care Hospital

INTRODUCTION

Non-fermenting gram-negative bacilli (NFGNB) infections have emerged as a serious health concern in ICUs. Multi-drug resistant (MDR) strains of NFGNB can evolve by acquiring resistance genes to at least one agent in three or more antibacterial categories. This study aimed to analyse the prevalence of NFGNB, the distribution of MDR strains, and antibiotic resistance trends of NFGNB in different ICUs of a tertiary care hospital over a period of five years.

MATERIALS AND METHODS

This retrospective study was conducted in a tertiary care teaching hospital in eastern India, including a total of 20,256 samples received from various ICUs over five years. Data retrieved from the Laboratory Information System (LIS) of the hospital, and repetitive isolates from the same patients, were excluded. All samples were processed according to standard microbiological protocols by automated systems. Data were entered into a Microsoft Excel spreadsheet (Microsoft® Corp., Redmond, WA, USA), analysed using Epi Info software, and presented using descriptive statistics. Chi-square and Fisher's exact tests (where appropriate) were used as tests of significance, with a p-value of <0.05 considered statistically significant.

RESULTS

A total of 18,032 culture-positive samples out of 20,256 samples showed growth of 18,659 bacteria. Out of these, 952 isolates were NFGNB. The prevalence of NFGNB was found to be 5.10% among all isolated bacteria. The predominant sources were respiratory samples (37.3%). Acinetobacter spp. emerged as the most prevalent NFGNB (46.5%), followed by Pseudomonas spp. (31%) and Burkholderia spp. (14.3%). Among the NFGNB isolates, 61.76% exhibited MDR, with the highest prevalence of MDR strains seen in Elizabethkingia spp. (94.7%). Among the most prevalent NFGNB, Acinetobacter spp., 64.8% were MDR strains. Trend analysis of antibiotic resistance patterns of Acinetobacter spp. indicated a substantial increase for trimethoprim-sulfamethoxazole by 18.5%, minocycline (44.4%), amikacin (20.4%), and ceftazidime (7.4%), whereas there was a reduced trend in resistance to carbapenems (6.5%), ciprofloxacin (4.7%), and cefepime (3.7%) over five years. In Pseudomonas spp., resistance to meropenem increased by 17.4%, and for ceftazidime (11.8%), amikacin (10.6%), and piperacillin-tazobactam (7.9%), whereas resistance to aztreonam diminished by 13.9%. Burkholderia spp. exhibited a 23.5% escalation in resistance to meropenem and ceftazidime (5.9%), while resistance to levofloxacin experienced a decrease of 30.2%.

CONCLUSIONS

The study showed the prevalence of various NFGNB as 5.10% in ICU settings, with Acinetobacter spp. (46.5%) being the most common isolated bacteria. Notably, 61.76% of the isolates were MDR. Antibiotic trend analysis over five years showed increasing resistance of Acinetobacter spp. to trimethoprim-sulfamethoxazole, minocycline, and ceftazidime, with improved susceptibility for carbapenems, ciprofloxacin, and cefepime. Pseudomonas spp. showed increased susceptibility to aztreonam and rising resistance for meropenem, piperacillin-tazobactam, ceftazidime, and amikacin. In Burkholderia spp., there was increased susceptibility to levofloxacin and rising resistance to meropenem and ceftazidime. These findings focus on the need for vigilant antibiotic stewardship, with the adoption of appropriate infection prevention and control practices to restrict the emergence and spread of MDR NFGNB infections in ICU settings of hospitals.

Susceptibility of clinical isolates of novel pathogen Stenotrophomonas sepilia to novel benzoquinolizine fluoroquinolone levonadifloxacin

Background

Stenotrophomonas sepilia, identified in 2021, is part of the Stenotrophomonas maltophilia complex (Smc) and shares high genomic identity with S. maltophilia. Resistance to levofloxacin, the recommended fluoroquinolone for S. maltophilia, is being increasingly reported. Recent studies indicate that levonadifloxacin, a novel benzoquinolizine, may be more effective. This study evaluates the antimicrobial efficacy of levofloxacin and levonadifloxacin against clinical isolates of S. sepilia.

Objectives

To assess the antibacterial effectiveness of levofloxacin and levonadifloxacin against novel pathogen S. sepilia.

Methods

A total of 116 S. maltophilia isolates, identified by MALDI-TOF MS, were collected from five centres across India. S. sepilia was confirmed by PCR using primers targeting a unique genomic sequence (NCBI accession number LXXZ00000000.1). Minimum inhibitory concentrations (MICs) of levonadifloxacin and levofloxacin were determined by using the microbroth-dilution method and Etest as per CLSI guidelines. The levofloxacin breakpoint was used to interpret MICs of levonadifloxacin.

Results

Among a total of 116 circulating S. maltophilia isolates collected, 46 were identified as S. sepilia, representing a prevalence rate of (∼40%), thus highlighting its significance as an important pathogen within the Smc. Both levofloxacin and levonadifloxacin demonstrated a 98% inhibition rate against the 46 S. sepilia tested. Only one S. sepilia isolate resistant to levofloxacin showed intermediate susceptibility to levonadifloxacin, which consistently had lower MICs.

Conclusions

Levofloxacin and levonadifloxacin show similar susceptibility rates against S. sepilia, with levonadifloxacin exhibiting lower MICs. Further studies are required to establish clinical utility of levonadifloxacin in managing these infections.

Species distribution and antimicrobial susceptibility of Burkholderia cepacia complex isolates in clinical infections: Experience from a tertiary care hospital, Southern India

PURPOSE

Burkholderia cepacia complex (Bcc) is a diverse group of environmental bacteria associated with opportunistic infections. The identification of Bcc using conventional methods poses challenges. Bcc infections are difficult to treat due to intrinsic antibiotic resistance. The study aimed to investigate the species distribution and antimicrobial susceptibility of clinical Bcc isolates.

METHODS

A total of 153 Bcc isolates obtained from clinical samples were analysed. Species identification was carried out using automated methods, including MALDI-TOF MS and VITEK2. Antimicrobial susceptibility testing was performed using the disc diffusion method.

RESULTS

Burkholderia cenocepacia (70.5%) emerged as the most prevalent species, followed by Burkholderia contaminans (9.8%) and Burkholderia cepacia (7.2%). Ventilator-associated pneumonia (38.6%) was the most common infection, followed by sepsis (28.1%). Co-existence of Bcc with other pathogens in many cases suggested potential co-infection scenarios. Antimicrobial susceptibility revealed that ceftazidime, co-trimoxazole and meropenem were the most effective drugs, while levofloxacin proved to be the least effective. Moderate susceptibility was noted to minocycline, with 4.6% of isolates exhibiting multi-drug resistance.

CONCLUSION

This study provides valuable insights into the prevalence, clinical associations, and antibiotic susceptibility of Bcc in India. It highlights the importance of Bcc as a nosocomial pathogen, especially in vulnerable patient populations. The findings contribute to understanding Bcc infections, their distribution, and emphasize the necessity for accurate identification methods in clinical settings.

Challenges and mitigation strategies associated with Burkholderia cepacia complex contamination in pharmaceutical manufacturing

Burkholderia cepacia complex (BCC) is a Gram-negative, non-spore-forming bacterium with more than 20 opportunistic pathogenic species, most commonly found in soil and water. Due to their rapid mutation rates, these organisms are adaptable and possess high genomic plasticity. BCC can cause life-threatening infections in immunocompromised individuals, such as those with cystic fibrosis, chronic granulomatous disease, and neonates. BCC contamination is a significant concern in pharmaceutical manufacturing, frequently causing non-sterile product recalls. BCC has been found in purified water, cosmetics, household items, and even ultrasound gel used in veterinary practices. Pharmaceuticals, personal care products, and cleaning solutions have been implicated in numerous outbreaks worldwide, highlighting the risks associated with intrinsic manufacturing site contamination. Regulatory compliance, product safety, and human health protection depend on testing for BCC in pharmaceutical manufacturing. Identification challenges exist, with BCC often misidentified as other bacteria like non-lactose fermenting Escherichia coli or Pseudomonas spp., particularly in developing countries where reporting BCC in pharmaceuticals remains limited. This review comprehensively aims to address the organisms causing BCC contamination, genetic diversity, identification challenges, regulatory requirements, and mitigation strategies. Recommendations are proposed to aid pharmaceutical chemists in managing BCC-associated risks and implementing prevention strategies within manufacturing processes.

Emerging infections in vulnerable hosts: Stenotrophomonas maltophilia and Elizabethkingia anophelis

PURPOSE OF REVIEW

This systematic review aimed to explore the recent trends in the epidemiology, risk factors, and antimicrobial susceptibility of two emerging opportunistic pathogens, Stenotrophomonas maltophilia and Elizabethkingia anophelis .

RECENT FINDINGS

Since 2020, numerous outbreaks of S. maltophilia and E. anophelis have been reported worldwide. Most of these outbreaks have been associated with healthcare facilities, although one outbreak caused by E. anophelis in France was considered a community-associated infection. In terms of antimicrobial susceptibility, trimethoprim/sulfamethoxazole (TMP-SMZ), levofloxacin, and minocycline have exhibited good efficacy against S. maltophilia . Additionally, cefiderocol and a combination of aztreonam and avibactam have shown promising results in in vitro susceptibility testing. For E. anophelis , there is currently no consensus on the optimal treatment. Although some studies have reported good efficacy with rifampin, TMP-SMZ, piperacillin/tazobactam, and cefoperazone/sulbactam, minocycline had the most favourable in vitro susceptibility rates. Cefiderocol may serve as an alternative due to its low minimum inhibitory concentration (MIC) against E. anophelis . The role of vancomycin in treatment is still uncertain, although several successful cases with vancomycin treatment, even with high MIC values, have been reported.

SUMMARY

Immunocompromised patients are particularly vulnerable to infections caused by S. maltophilia and E. anophelis , but the optimal treatment strategy remains inconclusive. Further research is necessary to determine the most effective use of conventional and novel antimicrobial agents in combatting these multidrug-resistant pathogens.

Burkholderia cepacia infections at sites other than the respiratory tract: A large case series from a tertiary hospital in Madurai

Sparsely reported extrapulmonary Burkholderia cepacia complex (Bcc) infections highlights the importance of this study. This was a retrospective chart review of 37 patients with extrapulmonary Bcc infections admitted between December 2019 and July 2022 in a tertiary hospital. Males accounted for 70% of cases. 78% had atleast one underlying comorbid illness. Among 37 isolates, 22 were from blood, others include exudates, urine and peritoneal fluid. Susceptibility rates of ceftazidime, meropenem, minocycline, cotrimoxazole and levofloxacin were 88, 88, 70, 65.7 and 56.7% respectively. Eleven died of septic shock and 24 patients (64.8%) had good outcomes, while two were lost to followup.

Stenotrophomonas isolates in a tertiary care centre in South India

PURPOSE

Stenotrophomonas maltophilia is an emerging multi-drug resistant pathogen increasingly isolated in India. This study aimed to identify patients from whom Stenotrophomonas maltophilia had been isolated and assess predictors of mortality in this population.

METHODS

This was a retrospective cohort study of hospitalized patients with a positive culture for S. maltophilia over a 3-year period. Clinical details and laboratory results were assessed from hospital records. Bivariate and multivariate analysis was used to identify risk factors for mortality.

RESULTS

One hundred and nineteen patients (mean age 48.6 years) were included in the study. Of these, 111 patients were hospitalized for at least 48 ​hours prior to culture and 98 were admitted in the intensive care unit. Bivariate analysis revealed multiple associations with mortality, including a background of renal, cardiac, autoimmune disease, recent carbapenam use and COVID-19 infection and increasing ventilatory requirement, lower PaO₂/FiO₂ (P/F) ratio, vasopressor use, thrombocytopenia, and hypoalbuminemia at the time of positive isolate. Multivariate analysis showed that autoimmune disease [OR 27.38; 95% CI (1.39-540)], a P/F ratio of less than 300 [OR 7.58; 95% CI (1.52-37.9)], vasopressor requirement [OR 39.50; 95% CI (5.49-284)] and thrombocytopenia [OR 11.5; 95% CI (2.04-65.0)] were statistically significantly associated with increased mortality, while recent surgery and receipt of antibiotics [OR 0.16; 95% CI (0.03-0.8)] targeted against S. maltophilia were associated with decreased mortality.

CONCLUSION

Stenotrophomonas maltophilia is primarily isolated in patients in the intensive care unit. In our study the need for vasopressors, autoimmune disease, lower P/F ratios and thrombocytopenia were associated with higher mortality. The association of targeted antibiotics with reduced mortality suggests that the pathogenic role of S. maltophilia should not be underestimated. This finding needs to be confirmed with larger, prospective studies.