First Survey of Metallo-β-Lactamase Producers in Clinical Isolates of Pseudomonas aeruginosa From a Referral Burn Center in Kurdistan Province

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Pseudomonas æruginosa (PA) is among the major agents of infection in burns. Multidrug-resistant strains are commonly isolated, which hampers the management of these patients. Our purpose was to study the incidence density of PA colonization and PA infection and to investigate the antibiotic susceptibility of strains isolated in patients hospitalized in the Trauma and Burn Center's Burn Unit (TBC-BU) in Tunisia. It is a retrospective study including 1649 non-repetitive strains of PA during an 8-year period (2012- 2019). PA was the most common organism in TBC-BU bacterial ecology (15%). The incidence density of PA colonization and PA infection was 16.1‰ days of in-patient stay (DH) and 16.5‰ DH, respectively. A positive and statistically significant correlation was found between PA colonization and PA infection (rs=1; p=0,004). The colonization strains were mainly isolated from skin (25.1%) and central catheters (22.3%). Bacteremia was the most common infection (19.5%). The skin was the most common source of bacteremia (22.1%) followed by central catheters (18.3%). The highest rates of antibiotic resistance were found with piperacillin-tazobactam (72.4%), ceftazidime (49.4%), meropenem (74%), imipenem (70.5%), amikacin (74.6%), ciprofloxacin (56.5%) and fosfomycin (35.3%). We did not identify any colistin-resistant strain. The multidrug resistance rate was 78%. The metallo-carbapenemase-producing strains rate was 14.4%.

Phenotypic and Molecular Survey of Metallo-beta-lactamase-producing Pseudomonas aeruginosa Isolated from Patients with Nosocomial and Non- Nosocomial Infections

BACKGROUND

Resistance to antimicrobial agents in Pseudomonas aeruginosa (P. aeruginosa) including carbapenems is a prominent problem in patients. The aim of this study is surveying Metallo-beta-lactamase (MBL)-producing P. aeruginosa isolated from patient specimens with nosocomial and non-nosocomial infections in Kurdistan province, Iran.

METHODS

In total, 146 Pseudomonas spp. were collected (December 2015 to August 2017). P. aeruginosa isolates were detected by phenotypic and polymerase chain reactions (PCR) of gyrB gene. Combination disk (CD) phenotypic test was used for the identification of MBL-producing strains and PCR was applied for identification of blaIMP and blaVIM genes in P. aeruginosa. Sensitivity and specificity of phenotypic tests were calculated as well. Fisher's exact test and logistic regression were used for data analysis (p≤0.05).

RESULTS

A total of 134 (91.78%) and 133 (91.09%) P. aeruginosa were detected using PCR and the phenotypic test, respectively. Fifty-six (41.79%) clinical isolates were isolated from patients with nosocomial infection. CD test proved that 67 out of 134 (50%) P. aeruginosa isolates were positive for MBL, of which 11 (8.20%) carried blaIMP gene. No significant relationship was found between MBL-producing P. aeruginosa and blaIMP genes; as well as between MBL-producing P. aeruginosa and blaIMP genes with age, sex, city of residence, inpatient/outpatient and specimen's type (p≥0.05).

CONCLUSION

Presence of MBL-producing P. aeruginosa strains and blaIMP genes were proved in this study; thus more precaution should be taken in the administration of carbapenem antibiotics to patients.

The threat of carbapenem-resistant gram-negative bacteria in a Middle East region

Data on the status of carbapenem-resistant microorganisms in the Middle East countries are scarce. The aim of this review was to collect available data regarding resistance to carbapenems in a Middle East region. Available data regarding carbapenem-resistant isolates were considered for evaluation in this review. Biomedical electronic databases were systematically searched to find related articles. The key terms used were "carbapenem-resistant, resistant gram-negative bacilli, Enterobacteriaceae, fermenting and non-fermenting gram-negative bacilli, Pseudomonas, Acinetobacter, Klebsiella and Iran". After primary screening, 275 relevant articles were selected to be assessed thoroughly. Resistance rate to carbapenems was reported between 1% and 86% during years 2006-2018. Most of the carbapenem-resistant microorganisms were isolated from burn patients. Modified Hodge test was a commonly used phenotypic test. Only in few studies, genotypic assays were considered. Pattern of antibiotic use can affect emergence of resistant microorganisms. Rational use of drugs, and specifically, antibiotics is a challenging issue in developing countries. Mean number of drugs per prescription in these countries was higher than the World Health Organization standards. Overuse of antibiotics, especially injectable ones, and easy access to antibiotics without prescription is a warning alarm for future antibiotic resistance in developing countries. Establishing antimicrobial stewardship's programs is new in the hospitals. Unfortunately, rules and regulatory issues to restrict antibiotic access in community pharmacies and prescription by general physicians are limited.

The Effects of Berberine and Palmatine on Efflux Pumps Inhibition with Different Gene Patterns in Pseudomonas aeruginosa Isolated from Burn Infections

BACKGROUND

Related Multidrug Resistance (MDR) to efflux pumps is a significant problem in treating infections caused by Pseudomonas aeruginosa (P. aeruginosa). Plant compounds have been identified as Pump Inhibitors (EPIs). In the current study, the potential effect of Berberine and Palmatine as EPIs were investigated on efflux pump inhibition through focusing on different gene patterns in P. aeruginosa isolated from burn infections.

METHODS

All isolates were collected and identified using the standard biochemical tests. Antimicrobial sensitivity was performed based on disk agar diffusion method for 12 antibiotics. MIC-MBC tests were also performed based on the broth microdilution method to detect synergistic relationship between ciprofloxacin, Berberine and Palmatine. Detection of mexA, mexB, mexC, mexD, mexE, mexF and mexX was conducted by PCR assay. Fisher's Exact test and Logistic Regression were used as statistical tools.

RESULTS

A total of 60 P. aeruginosa isolates were collected. The highest and lowest levels of resistance were found to be respectively against clindamycin and tigecycline. Comparing the MIC with MBC distribution, it was found that Berberine and Palmatine lower the MIC-MBC level of ciprofloxacin. The PCR results indicated that the highest frequency is about MexAB-OprM operon. The statistical analysis among different gene patterns of efflux pumps showed that there were no significant relationships between the effectiveness of Berberine and Palmatine (p>0.05).

CONCLUSION

It can be speculated that Berberine and Palmatine both act as EPIs and can be used as auxiliary treatments with the purpose of increasing the effect of available antibiotics as well as decreasing the emergence of MDR bacteria. The efficiency of these combinations should be studied further under in vivo conditions to have a more comprehensive conclusion regarding this issue.

Characterization of clinical extensively drug-resistant Pseudomonas aeruginosa in the Hunan province of China

Background

Pseudomonas aeruginosa strains that are classed as extensively drug resistant (XDR-PA) are resistant to all antibiotics except for one or two classes and are frequently the cause of hard-to-treat infections worldwide. Our study aimed to characterize clinical XDR-PA isolates recovered during 2011–2012 at nine hospitals in the Hunan province of China.

Methods

Thirty-seven non-repetitive XDR-PA strains from 37 patients were investigated for genes encoding antimicrobial resistance determinants, efflux pumps, outer membrane proteins, and movable genetic elements using polymerase chain reaction (PCR). The expression of genes encoding the efflux pump component MexA and the outer membrane protein OprD was measured using real-time PCR. In addition, clonal relatedness of these XDR-PA isolates was analyzed by pulsed-field gel electrophoresis (PFGE).

Results

Various genes encoding antimicrobial resistance determinants were found in all isolates. In particular, the bla_TEM-1, bla_CARB, armA, bla_IMP-4, bla_VIM-2, and rmtB, were found in 100, 37.8, 22, 22, 19 and 5 % of the isolates, respectively. Remarkably, two isolates coharbored bla_IMP-4, bla_VIM-2, and armA. In all 37 antibiotic-resistant strains, the relative expression of oprD was decreased while mexA was increased compared to the expression of these genes in antibiotic-susceptible P. aeruginosa strains. All of the XDR-PA isolates harbored class I integrons as well as multiple other mobile genetic elements, such as tnpU, tnp513, tnpA (Tn21), and merA. A high genotypic diversity among the strains was detected by PFGE.

Conclusions

Multiple antibiotic-resistance mechanisms contributed to the drug resistance of the XDR-PA isolates investigated in this study. Thus, the XDR-PA isolates in this area were not clonally related. Instead, multiple types of movable genetic elements were coharbored within each XDR-PA isolate, which may have aided the rapid development of these XDR-PA strains. This is the first report of XDR-PA strains that coharbor bla_IMP-4, bla_VIM-2, and armA.

Epidemiology of VIM-1-imipenem resistant Pseudomonas aeruginosa in Iran: A systematic review and meta-analysis

BACKGROUND

Pseudomonas aeruginosa is an opportunistic human pathogen which causes serious problems, especially in people who have immunodeficiency. Metallo beta-lactamase (MBL) resistance in this bacterium has led some difficulties in treating bacterial infections. MBLs are being reported with increasing frequency worldwide. The aim of the present systematic review and meta-analysis was to collect data about the relative frequency (RF) of VIM-1-imipenem resistant P. aeruginosa (VIM-1-IRPA) in different regions of Iran and report an overall prevalence if possible.

MATERIALS AND METHODS

PubMed, ISI web of science, Scopus and Google Scholar were searched using following key terms: "P. aeruginosa," "imipenem," "VIM-1" and "Iran" were. Articles/abstracts, which used clinical specimens and had done polymerase chain reaction to detect the VIM-1 gene of MBL genes, were included in this review. STATA SE version 11.2 (StataCorp, College Station, TX, USA) was used for statistical analysis.

RESULTS

Out of 5457 results found, 10 articles were eligible to be included in our systematic review and meta-analysis. These studies were carried out in Tehran, Isfahan, Kurdistan, Ahvaz, Markazi and Northwest of Iran (Orumieh and Tabriz). Pooled estimation of 1972 P. aeruginosa samples showed that 13% (95% confidence interval = 10.5-16.5%]) of strains were VIM-1 positive. VIM-1-IRPA RF in different studies varied from 0% to 19.5% in Isfahan and Markazi provinces, respectively. We found a moderate heterogeneity (Chochran Q-test, P = 0.032, I-squared = 50.7%) of VIM-1-IRPA RF among studies.

CONCLUSION

According to the results of this study VIM-1-IRPA RF in Iran is in low-level Prevention strategies to reduce the prevalence rates of VIM-1 positive strains in Iran are needed.