Antimicrobial susceptibility pattern of clinical isolates of Pseudomonas aeruginosa isolated from patients of lower respiratory tract infections

Antimicrobial resistance and carbapenemase dissemination in Pseudomonas aeruginosa isolates from Libyan hospitals: a call for surveillance and intervention

Pseudomonas aeruginosa is a multidrug-resistant bacterium capable of forming biofilms. This study aimed to assess resistance of clinical isolates from Libyan hospitals to antipseudomonal antibiotics, the prevalence of selected extended-spectrum β-lactamases and carbapenemase genes among these isolates, and the microorganisms' capacity for alginate and biofilm production. Forty-five isolates were collected from four hospitals in Benghazi and Derna, Libya. Antimicrobial susceptibility was determined using agar disc diffusion. The presence of resistance genes (blaCTXM, blaTEM, blaSHV-1, blaGES-1, blaKPC, and blaNDM) was screened using PCR. Biofilm formation was quantified via the crystal violet assay, while alginate production was measured spectrophotometrically. Resistance to antipseudomonal antibiotics ranged from 48.9% to 75.6%. The most prevalent resistance gene was blaNDM (26.7%), followed by blaGES-1 (17.8%). Moreover, all isolates demonstrated varying degrees of biofilm-forming ability and alginate production. No statistically significant correlation was found between biofilm formation and alginate production. The dissemination of resistant genes in P. aeruginosa, particularly carbapenemases, is of great concern. This issue is compounded by the bacteria's biofilm-forming capability. Urgent intervention and continuous surveillance are imperative to prevent further deterioration and the catastrophic spread of resistance among these formidable bacteria.

Estimation, Evaluation and Characterization of Carbapenem Resistance Burden from a Tertiary Care Hospital, Pakistan

Carbapenem resistance has become major concern in healthcare settings globally; therefore, its monitoring is crucial for intervention efforts to halt resistance spread. During May 2019–April 2022, 2170 clinical strains were characterized for antimicrobial susceptibility, resistance genes, replicon and sequence types. Overall, 42.1% isolates were carbapenem-resistant, and significantly associated with Klebsiella pneumoniae (K. pneumoniae) (p = 0.008) and Proteus species (p = 0.043). Carbapenemases were detected in 82.2% of isolates, with blaNDM-1 (41.1%) associated with the ICU (p < 0.001), cardiology (p = 0.042), pediatric medicine (p = 0.013) and wound samples (p = 0.041); blaOXA-48 (32.6%) was associated with the ICU (p < 0.001), cardiology (p = 0.008), pediatric medicine (p < 0.001), general surgery (p = 0.001), general medicine (p = 0.005) and nephrology (p = 0.020); blaKPC-2 (5.5%) was associated with general surgery (p = 0.029); blaNDM-1/blaOXA-48 (11.4%) was associated with general surgery (p < 0.001), and wound (p = 0.002), urine (p = 0.003) and blood (p = 0.012) samples; blaOXA-48/blaVIM (3.1%) was associated with nephrology (p < 0.001) and urine samples (p < 0.001). Other detected carbapenemases were blaVIM (3.0%), blaIMP (2.7%), blaOXA-48/blaIMP (0.1%) and blaVIM/blaIMP (0.3%). Sequence type (ST)147 (39.7%) represented the most common sequence type identified among K. pneumoniae, along with ST11 (23.0%), ST14 (15.4%), ST258 (10.9%) and ST340 (9.6%) while ST405 comprised 34.5% of Escherichia coli (E. coli) isolates followed by ST131 (21.2%), ST101 (19.7%), ST10 (16.0%) and ST69 (7.4%). Plasmid replicon types IncFII, IncA/C, IncN, IncL/M, IncFIIA and IncFIIK were observed. This is first report describing the carbapenem-resistance burden and emergence of blaKPC-2-ST147, blaNDM-1-ST340 and blaNDM-1-ST14 in K. pneumoniae isolates and blaNDM-1-ST69 and blaNDM-1/blaOXA-48-ST69 in E. coli isolates coharboring extended-spectrum beta-lactamases (ESBLs) from Pakistan.

Drug Resistance among Major Non-fermenting Gram-negative Pathogens Isolated from Respiratory Tract Infections in a Tertiary Care Hospital of South Karnataka

Non-fermenting gram-negative bacteria (NFGNB) frequently exhibit drug resistance. The purpose of this study was to determine the drug resistance pattern among the NFGNB isolates causing respiratory tract infections (RTIs). A retrospective analysis of the antimicrobial susceptibility pattern of non-fermenters causing RTIs over four years (2016- 2019) was done and the change in drug resistance pattern was studied. A total of 653 cases were obtained that included 191 (29.2%) Moraxella catarrhalis, 283 (43.3%) Pseudomonas aeruginosa, and 132 (20.2%) Acinetobacter baumannii, 47 (7.2%) Stenotrophomonas maltophilia isolates. A higher resistance (82.6%) was observed for piperacillin-tazobactam and cefpirome, followed by imipenem (79.5%) and ciprofloxacin (76.5 %) for A. baumannii isolates. A sharp decline in resistance pattern for piperacillin, cefpirome, Imipenem and cefoperazone-sulbactam in 2019 and an increasing resistance to gentamycin and ciprofloxacin were noted. Among P. aeruginosa isolates, 94% aztreonam and 83.4% cefoperazone-sulbactam resistance were detected. There was an increased resistance for cefpirome and piperacillin and a decreased resistance for Imipenem was recorded in 2019. In cases of M. catarrhalis, 22.51% of isolates were resistant to ciprofloxacin, followed by erythromycin (18.32%) and tetracycline (17.80 %). S. maltophilia showed a 100% sensitivity for co-trimoxazole and 2.1% resistance for ciprofloxacin. A constantly changing antibiotic-resistant pattern of non-fermenters compels for a continuous update of drug-resistant trends through a longitudinal surveillance program in different geographical areas.

Evaluating the appropriateness of carbapenem and piperacillin-tazobactam prescribing in a tertiary care hospital in Saudi Arabia

Background

Antimicrobial resistance (AMR) is presently considered an emergent major global public health concern and excessive and/or inappropriate use of broad-spectrum antimicrobials contribute to the development of AMR.

Objective

To evaluate the appropriateness of carbapenems and piperacillin-tazobactam use in a tertiary care hospital.

Methods

A retrospective, observational, cross-sectional, drug-utilization study was conducted. The study included all adult hospitalized patients who had received at least one dose of the antimicrobials during their admission for the period between 1 January 2016 and 31 December 2017. The appropriateness of antimicrobial therapy was evaluated according to the Infectious Diseases Society of America (IDSA) guidelines with the consideration of the institutional antibiogram.

Results

Overall, 2731 patients received 5005 courses with one of the antimicrobials, for a total of 5045.9 defined daily doses (DDD) of imipenem-cilastatin, 6492.3 of meropenem and 15,595 of piperacillin-tazobactam (4.93, 6.34 and 15.24 DDD/100 bed days, respectively). The mean age of the patients who received either antimicrobial was 55.5 ± 20.3 years, with a 14-day average length of hospital stay. About half (52%) of the prescriptions were written for patients treated in the medical ward. Pneumonia (26.6%) and sepsis (24.9%) were the most common indication for the initiation of antimicrobial therapy. Of the assessed prescriptions, only 2787 (56.5%) were prescribed appropriately, with 2142 (43.5%) deemed inappropriate. The three most common reasons for inappropriate prescription were: the spectrum of activity was too broad (44.6%), followed by antimicrobial use without culture request (32.4%), and failure of suitable antimicrobial de-escalation (19.9%).

Conclusions

The study indicates that the overall rate of inappropriateness was high, emphasizing the need to develop initiatives to effectively improve broad-spectrum antimicrobial prescribing.

Emergence of multidrug-resistant non-fermentative gram negative bacterial infection in hospitalized patients in a tertiary care center of Nepal

Objective

This study was designed for the characterization and establishment of antibiotic susceptibility profiles of non-fermentative gram negative bacteria isolated from hospitalized patients in a tertiary care hospital of Nepal.

Results

A total of 402 non-fermentative gram negative bacteria was isolated in 1486 culture-positive cases from 6216 different clinical samples obtained from hospitalized patients. Among total non-fermentative gram negative bacterial isolates, the highest number was recovered from specimens collected from lower respiratory tract infections (n = 173, 43.0%) of hospitalized patients followed by pus/swab samples (n = 99, 24.6%) and urinary tract infections (n = 49, 12.2%). The most common non-fermentative gram negative bacteria identified were Acinetobacter baumannii (n = 177, 44.0%), Pseudomonas aeruginosa (n = 161, 40.1%) and Burkholderia cepacia complex (n = 33, 8.2%). These bacterial isolates exhibited a higher rate of insusceptibility to beta-lactam antibiotics, fluoroquinolones, and aminoglycosides. On the other hand, all the isolates of P. aeruginosa and A. baumannii were completely susceptible to colistin sulfate and polymyxin B. Among total isolates, 78.1% (n = 314) were multidrug-resistant with a high rate of multidrug-resistant among A. baumannii (91.0%).

Molecular epidemiology of Pseudomonas aeruginosa isolated from lower respiratory tract of ICU patients

Lower respiratory tract infections (LRTIs) caused by Pseudomonas aeruginosa are the most common infection among hospitalized patients, associated with increased levels of morbidity, mortality and attributable health care costs. Increased resistant Pseudomonas worldwide has been quite meaningful to patients, especially in intensive care unit (ICUs). Different species of Pseudomonas exhibit different genetic profile and varied drug resistance. The present study determines the molecular epidemiology through DNA fingerprinting method and drug resistance of P. aeruginosa isolated from patients with LTRIs admitted in ICU. A total of 79 P. aeruginosa isolated from patients with LRTIs admitted in ICU were characterized by Restriction Fragment Length Polymorphism (RFLP), Random Amplified Polymorphic DNA (RAPD) and Repetitive Extrapalindromic PCR (REP-PCR). Antibiotic resistance was determined by minimum inhibitory concentration (MIC) assay while MDR genes, viz, blaTEM, blaOXA, blaVIM, blaCTX-M-15 were detected by polymerase chain reaction (PCR). Of the 137 Pseudomonas sp isolated from ICU patients, 57.7% of the isolates were reported to be P. aeruginosa. The overall prevalence of P. aeruginosa among the all included patients was 34.5%. The RAPD analysis yielded 45 different patterns with 72 clusters with 57% to 100% similarity level. The RFLP analysis yielded 8 different patterns with 14 clusters with 76% to 100% similarity level. The REP PCR analysis yielded 37 different patterns with 65 clusters with 56% to 100% similarity level. There was no correlation among the different DNA patterns observed between the three different methods. Predominant of the isolates (46.8%) were resistant to amikacin. Of the 79 isolates, 60.8% were positive for blaTEM gene and 39.2% were positive for blaOXA gene. P. aeruginosa was predominantly isolated from patients with LRTIs admitted in ICU. The difference in the similarity level observed between the three DNA fingerprinting methods indicates that there is high inter-strain variability. The high genetic variability and resistance patterns indicates that we should continuously monitor the trend in the prevalence and antibiotic resistance of P. aeruginosa especially in patients with LRTIs admitted in ICU.

Antimicrobial resistance and putative virulence genes of Pseudomonas aeruginosa isolates from patients with respiratory tract infection

Introduction

Pseudomonas aeruginosa is a common agent causing community acquired and nosocomial respiratory tract infections, with particularly life-threatening manifestations in patients who are immunocompromised of who have cystic fibrosis. This study investigated the occurrence of extended-spectrum β-lactamases (ESBLs) and metallo β-lactamase (MBL) in association with important putative virulence genes and genotypes variation among P. aeruginosa isolates from respiratory tract infection of Jordanian patients.

Methods

Over a period of 8-month, a total of 284 respiratory tract samples were obtained from patients diagnosed with respiratory tract infection while attending the Pulmonary Clinic/Intensive Care Unit, Jordan University Hospital (JUH). At the time of sampling most were inpatients (86.9%). Samples were cultured specifically for P. aeruginosa.

Results

A total of 61/284 (21.5%) P. aeruginosa isolates were recovered from respiratory samples of patients. The percentage of MDR P. aeruginosa isolates was 52.5%, and all isolates were susceptible to colistin with lower rates of susceptibility to other tested antibiotics. Positive genes of bla_CTX-M, bla_VEB, bla_TEM, bla_GES and bla_SHV were detected in 68.9%, 18.9%, 18.9%, 15.6% and 12.5% of isolates, respectively. Genotyping revealed no significant genetic relationship among MDR P. aeruginosa isolates from hospitalized patients as judged by the constructed dendrogram and the presence of 14 genotypic groups. The percentages of the virulence genes algD, lasB, toxA, exoS, and exoU among P. aeruginosa isolates were 98%, 98%, 80%, 33% and 33%, respectively, and 87% of isolates produced pyocyanin.

Conclusion

The present study demonstrates high occurrence of MDR P. aeruginosa isolates carrying bla_CTX-M genes. No specific associations were found between antibiotic resistance, virulence genes and genotypes among MDR isolates.

Five-Year Antimicrobial Susceptibility of Pseudomonas aeruginosa from a Local Tertiary Hospital in Bacolod City, Philippines

Over five years, a total of 646 P. aeruginosa isolates was acquired from different clinical specimens and their resistance to the commonly used anti-pseudomonal antibiotics was determined. The majority of the isolates were from respiratory (60.99%) and urinary sources (23.22%) while the least came from transudates and exudates (2.01%). Most of the samples were acquired from older adults (77.55%), most of whom were admitted (67.03%). Amikacin was found to be the most effective drug with a resistance rate of 7.5%, followed by piperacillin/tazobactam (8.5%) and gentamicin (13.5%). On the other hand, 26.7% of the isolates were resistant to levofloxacin. Almost 100% of the isolates were screened positive for AmpC production, which may suggest inducible resistance against expanded spectrum beta-lactamase. Furthermore, for the last three years, P. aeruginosa isolates from this area have been noted to have decreasing resistance only to aztreonam and gentamicin. Also, for five years, a mean MAR index of 0.17 was noted which indicates either proper antibiotic use or most isolates did not come from high-risk areas. Moreover, there was no significant difference in the resistance of P. aeruginosa when compared by specimen source (p = 0.662), but significant when compared by year band (p = 0.02).

High burden of antimicrobial resistance among gram negative bacteria causing healthcare associated infections in a critical care unit of Nepal

Background

Healthcare associated infections (HCAI) and antimicrobial resistance are principal threats to the patients of intensive care units and are the major determining factors for patient outcome. They are associated with increased morbidity, mortality, excess hospitalization and financial costs. The present study is an attempt to investigate the spectrum and antimicrobial resistance of bacterial isolates involved in healthcare associated infections (HCAI) in the patients of a critical care unit at a tertiary care university hospital in Kathmandu, Nepal.

Methods

A laboratory based study was conducted over the period of 15 months (January 2014 to March 2015) among the patients of intensive care unit of Tribhuvan University Teaching Hospital, Kathmandu, Nepal. Clinical specimens from patients with suspected healthcare-associated infection were processed and bacterial isolates were identified with standard microbiological methods. Antimicrobial susceptibilities of the isolated strains were determined according to the CLSI guidelines and β-lactamases (ESBL, AmpC, MBL and KPC) were detected by various phenotypic tests.

Results

One hundred and forty nine clinical specimens received from 135 patients suspected of HCAI (out of 491 patients) were found with significant bacterial growth. Specimens were from patients suspected of hospital-acquired pneumonia (16%, 79/491), bloodstream infections (5.7%, 28/491), surgical site infections (4.7%, 23/491), and urinary tract infections (3.9%, 19/491). Acinetobacter spp., Klebsiella spp., Escherichia coli and Burkholderia cepacia were the leading bacterial pathogens. Extremely high level of drug resistance (95.8%) along with the production of β-lactamases (ESBL; 43.7%, AmpC; 27.5%), MBL; 50.2% and KPC; 4.2%) was observed among Gram negative bacterial isolates.

Conclusion

Healthcare associated infections are very common in our ICU. Gram negative bacterial pathogens are major culprits associated with these infections and there is alarming state of drug resistance among these isolates. Continuous surveillance and establishment of preventive and control measures of healthcare associated infections are urgently needed in our setting.

Antimicrobial susceptibility patterns of clinical isolates of Pseudomonas aeruginosa isolated from patients of respiratory tract infections in a Tertiary Care Hospital, Peshawar

Objective:

This study aims to determine the prevalence and susceptibility pattern of Pseudomonas aeruginosa and multidrug-resistant (MDR) isolates in patients suffering from respiratory tract infection.

Methods:

A cross sectional study was conducted from January to December 2014 in Northwest General Hospital and Research Centre, Peshawar. A total of 615 sputum samples were collected from both in and out-patients. Sputum samples were collected as per standard procedure and were inoculated on Blood, MacConkey and Chocolate agar. The isolates were identified by standard protocols using biochemical tests. The antibiotic susceptibility pattern of each isolate was checked as per Clinical and Laboratory Standards Institute (CLSI) guidelines using Kirby-Bauer’s disc diffusion method.

Results:

Out of 615 sputum samples, 354 (57.56%) were culture positive. Out of these a total of 71 (20.05%) strains of Pseudomonas were isolated, where 54.93% was from males and 45.07% were from females (Mean age was 44.29 ± 22.72:). Highest sensitivity was seen to Amikacin (92.86%) followed by Meropenem (91.55%) while lowest sensitivity was seen to Cefoperazone + Sulbactam (16.9%). There were 39.44% MDR strains, out of which 25% were Extensively Drug Resistant (XDR) and 10.71% were Pan Drug Resistant (PDR). In vitro susceptibility of MDR isolates showed highest sensitivity to Amikacin (82.14%) followed by Carbapenems (78.57%). All MDR isolates were resistant to Cefoperazone + Sulbactam. Resistance to Piperacillin + Tazobactam was 96.43%.

Conclusion:

Pseudomonas aeruginosa is one of the commonly isolated organisms and it is becoming more resistant to commonly used antibiotics. Carbapenems and aminoglycosides were the two classes of drugs that showed highest activity against Pseudomonas aeruginosa.

Integron occurrence is linked to reduced biocide susceptibility in multidrug resistant Pseudomonas aeruginosa

OBJECTIVE

Integrons are gene acquisition systems commonly found in bacterial genomes that play a major role in the dissemination of resistance to antibiotics. This work aimed to study the relationship between the presence of integrons and the reduced susceptibility of multidrug-resistant (MDR) Pseudomonas aeruginosa isolates towards different groups of biocides.

METHODS

The antimicrobial susceptibility patterns of 104 clinical isolates were determined against different antibiotics by the disk diffusion method. The isolates were also tested for their susceptibility to six biocides (glutaraldehyde, benzalkonium chloride, cetrimide, chlorhexidine gluconate, chlorocresol and gluconate, and phenyl mercuric nitrate) by agar dilution. The presence of integrons and resistance genes in MDR isolates were detected by polymerase chain reaction.

RESULTS

Thirty-six Pseudomonas isolates were MDR, and the majority of these isolates showed reduced susceptibility to biocides. In the MDR isolates, Class I integron was detected in 22 isolates (61.1%), while Class II and III integrons were identified in only four isolates (11.1%), In addition, aacA4 and qacE genes were detected in 22 (61.1%) and 11 (30.5%) isolates, respectively. Integron I-positive isolates showed reduced susceptibility to tested biocides.

CONCLUSIONS

The current study reveals the presence of different classes of integrons, with class I being predominant. Class I integron may be responsible for generating MDR P. aeruginosa isolates with reduced susceptibility to biocides. This linkage between integrons and biocide resistance in MDR-Pseudomonas isolates is notable and could be clinically important. Strict antibiotic prescription policies and the adequate use of biocides could help in controlling this problem.

Multi drug resistant Pseudomonas aeruginosa: Pathogen burden and associated antibiogram in a tertiary care hospital of Pakistan

Pseudomonas aeruginosa is an important pathogen of both community and hospital acquired infections, and a major threat to public health for continuous emergence of multi-drug resistance. Current prevalence and pattern of multidrug resistance in the clinical isolates of P. aeruginosa is reported here. Samples were collected from September 2013 to January 2014 tertiary care hospital, Peshawar. Samples were subjected to phenotypic and molecular based detection of P. aeruginosa and were further processed for multidrug resistance pattern. Out of 3700 samples, 102 were identified as MDR P. aeruginosa. Prevalence of MDR isolates were found in pus (34.3%), wounds (28.4%), urine (19.6%), blood (14.7%) and sputum (2.9%) respectively. Isolates were more resistant to Sulphamethoxazole/Trimethoprim (98.04%), Amoxycillin/Clavulanic acid, Doxycycline and Chloramphenicol (95.1%) each, while least resistant to Imipenem (43.1%), Cefoperazone/Sulbactam (50.98%) and Amikacin (53.9%). Extensive MDR pattern was observed in P. aeruginosa was found as (n = 17, 16.6%) isolates were resistant to all four classes of antibiotics. Increased burden of MDR P. aeruginosa was documented in the study. Moreover, some isolates were even resistant to four classes of antibiotics. Findings of the study will be helpful to devise an appropriate antibiotic treatment strategy against MDR P. aeruginosa to cope the chances of evolving resistant pathogens.

ENDOPHTHALMITIS CAUSED BY PSEUDOMONAS AERUGINOSA: Clinical Features, Antibiotic Susceptibilities, and Treatment Outcomes

PURPOSE

To report the clinical features, antibiotic susceptibilities, and visual outcomes associated with endophthalmitis caused by Pseudomonas aeruginosa.

METHODS

A consecutive case series. Microbiology database records were retrospectively reviewed for all patients with endophthalmitis caused by P. aeruginosa from January 1, 2002, to December 31, 2012, at a large university referral center. The corresponding clinical records were then reviewed to evaluate the endophthalmitis clinical features and treatment outcomes.

RESULTS

In the 12 patients identified, clinical settings included postcataract surgery (n = 4), postpenetrating keratoplasty (n = 3), endogenous source (n = 2), post-pars plana vitrectomy (n = 1), trabeculectomy bleb-associated setting (n = 1), and glaucoma drainage implant-associated setting (n = 1). All patients presented with hypopyon. Presenting visual acuity was hand motions or worse in all cases. All isolates were susceptible to ceftazidime and levofloxacin. When comparing isolates in this study with isolates from a previous study (1987 to 2001), the minimal inhibitory concentration required to inhibit 90% of isolates (MIC 90, in micrograms per milliliter) remained the same for ceftazidime (8), ciprofloxacin (0.5), imipenem (4), tobramycin (0.5), and amikacin (4). Initial treatment strategies were vitreous tap and injection (n = 9) and pars plana vitrectomy with intravitreal antibiotics (n = 3). Final visual acuity was light perception or worse in 11 of the 12 patients (92%). Five patients underwent enucleation (42%).

CONCLUSION

All isolates were susceptible to ceftazidime and levofloxacin, and all MIC 90s for isolates in the current period compared with isolates from 1987 to 2001 remained identical. Despite early and appropriate treatment, outcomes were generally poor with a high rate of enucleation.

Microbiological profile of lower respiratory tract infections in neurological intensive care unit of a tertiary care center from Central India

Background:

Lower respiratory tract infections (LRTI's) are the most frequent infections among patients in intensive care units. The consequences of increased drug resistance are far reaching since bacterial infection of the lower respiratory tract (LRT) is a major cause of death from infectious disease.

Objective:

The study was conducted with the aim of determining the bacterial etiology of LRTI in the neuro intensive care unit (NICU) as well as to update the clinicians with the various antimicrobial alternatives available in the treatment of LRTI.

Subjects and Methods:

The study was conducted for the period of 3 years from January 2010 to December 2012 in the Microbiology Department of a Teaching Tertiary Care Hospital. The LRT specimens from 230 patients admitted in a NICU during the study period were processed. Following culture, the isolated organisms were identified and antimicrobial sensitivity was performed by standard methods.

Results:

Out of the 230 LRT specimens evaluated, 198 (86.08%) were culture positive. A total of 254 pathogens were recovered with a predominance of Gram-negative isolates (n = 243; 96.05%) Pseudomonas aeruginosa was the most dominant pathogen followed by Klebsiella pneumoniae. Alarmingly high percentage of extended spectrum beta-lactamase and methicillin resistant Staphylococcus aureus isolates were detected. The resistance to cephalosporins, aminoglycosides and carbapenem were remarkable.

Conclusions:

Therefore, we can conclude that for effective management of LRTI's, an ultimate and detailed bacteriological diagnosis and susceptible testing is required to overcome global problem of antibiotic resistance.

Evaluating the appropriate use of piperacillin/tazobactam in a community health system: a retrospective chart review

Noting inappropriate uses of piperacillin/tazobactam at their institution, the authors emphasize the need for antimicrobial stewardship efforts, as well as infection-control practices, to curtail drug resistance, reduce costs, and minimize adverse events.