Prevalence of Extended-Spectrum β-Lactamases in Multidrug-Resistant Klebsiella pneumoniae Isolates in Jordanian Hospitals

The increase in the prevalence of infections caused by certain bacteria, such as Klebsiella pneumonia (K. pneumoniae), is a global health concern. Bacterial production of an enzyme called extended-spectrum beta-lactamase (ESBL) can generate resistance to antimicrobial therapeutics. Therefore, between 2012 and 2013, we investigated K. pneumoniae that produce ESBLs with the prevalence of individual genes including blaSHV, blaCTX-M, blaTEM, and blaOXA isolated from clinical samples. A total of 99 variable diagnostic samples including blood from hematological malignancies (n = 14) or other clinical sources including sputum, pus, urine, and wound (n = 85) were analyzed. All samples' bacterial type was confirmed and their susceptibility to antimicrobial agents was established. Polymerase chain reaction (PCR) amplification was carried out to ascertain presence of specific genes that included blaSHV, blaCTX-M, blaTEM, and blaOXA. Plasmid DNA profiles were determined to assess significance between resistance to antimicrobial agents and plasmid number. It was found that among non-hematologic malignancy isolates, the highest rate of resistance was 87.9% to imipenem, with lowest rate being 2% to ampicillin. However, in hematologic malignancy isolates, the highest microbial resistance was 92.9% to ampicillin with the lowest rate of resistance at 28.6% to imipenem. Among collected isolates, 45% were ESBL-producers with 50% occurrence in hematologic malignancy individuals that were ESBL-producers. Within ESBL-producing isolates from hematologic malignancy individuals, blaSHV was detected in 100%, blaCTX-M in 85.7%, and blaTEM and blaOXA-1 at 57.1% and 27.1%, respectively. In addition, blaSHV, blaCTX-M, and blaOXA were found in all non-hematological malignancy individuals with blaTEM detected in 55.5% of samples. Our findings indicate that ESBLs expressing blaSHV and blaCTX-M genes are significantly prevalent in K. pneumoniae isolates from hematologic malignancy individuals. Plasmid analysis indicated plasmids in isolates collected from hematological malignancy individuals. Furthermore, there was a correlation between resistance to antimicrobial agents and plasmids within two groups analyzed. This study indicates an increase in incidence of K. pneumoniae infections displaying ESBL phenotypes in Jordan.

Evolution of the Antimicrobial resistance of Bacteria causing Urinary Tract Infections

BACKGROUND

The bacteria, Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae), are the main reasons for urinary tract infections (UTIs). This research aimed to investigate the isolation of etiologic agents from patients with UTI; it also investigates the antibiotic resistance activities and incidence of ESBL genes between different clinical separates of uropathogenic E. coli, determining their association with ESBL genes.

METHODS

The study enrolled 1000 positive growth isolates. The predominant pathogen associated with urinary tract infection, Gram-negative, were the main isolates from UTI patients, including E. coli, K. pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus aureus and Enterococcus faecalis.

RESULTS

Among suspicious cases of urinary tract infection, we showed that 15.2% of the patients had UTI, and female patients in the childbearing age group were more affected. 644 E. coli (64.4%) and 322 (32.2%) K. pneumoniae were more isolated. Among 936 (93.6%) ESBL producing bacteria, 614 (61.4 %) E. coli showedhigh resistance to the antibiotics, Cefotaxime (85.7 %), Cefepime (85.7 %), Ciprofloxacin (83.1 %) and Kanamycin (77.9 %). Most ESBL-producing K. pneumoniae were multidrug-resistant (MDR). Nitrofurantoin, gentamycin, and imipenem were the most effective antibiotics for ESBL-producing E. coli isolates.

CONCLUSION

This study shows that the high rates of MDR Escherichia coli infection in our hospital were frequentative reasons for UTI. Nitrofurantoin and aminoglycosides were the most beneficial first-line drugs to be applied in the cases of UTI. It is recommended to conduct regular investigations on the drug resistance of all isolates and formulate helpful antibiotic treatment policies in China. It is important to determine the prevalence of ESBL in urine E. coli and K. pneumoniae isolates because it has a great influence on the selection of suitable antibacterial agents. In short, more than half of ESBL producers have multiple drug resistance (MDR).

Extended-Spectrum β-Lactamases among Enterobacteriaceae Isolated from Urinary Tract Infections in Gaza Strip, Palestine

Background

Extended-spectrum β-lactamase-producing organisms causing urinary tract infections are increasing in incidence and pose a major impendence to health-care facility, having limited therapeutic options. This study aimed to assess the prevalence of ESBLs in Enterobacteriaceae isolates causing urinary tract infections in Gaza strip, Palestine, and to characterize β-lactamase types and associated resistance genes.

Methods

Eighty-five Enterobacteriaceae isolates were recovered from urinary tract infections within three months in Gaza Strip hospitals. The characterization of β-lactamase genes and the genetic environments of CTX-M, the identification of associated resistance genes, and the presence and characterization of integrons were tested by PCR and sequencing.

Results

The occurrence rate of ESBL among tested isolates was 30 (35.3%), and among ESBL-positive isolates, bla_CTX-M was the highest followed by bla_TEM. ESBL-CTX-M-1 group was confirmed in 93.3%, and the remaining carried CTX-M-9 group. CTX-M-15, CTX-M-3, CTX-M-1, CTX-M-14, CTX-M-27, and CTX-M-37 enzymes were demonstrated among the isolates with the majority (73%) being CTX-M-15. ISEcp-1 was demonstrated in 27 (90%, high incidence) of ESBL isolates. Class 1 integrons have been detected in higher rates (53.3%) in ESBL-positive isolates in comparison with non-ESBL isolates (6, 33.3%). Cassettes of integron-1 contain (aadA1, aadA2, aadA5, dfrA5, dfrA7, dfrA12, and dfrA17) genes. The aac(6′)-Ib-cr gene was demonstrated in 36.7% of ESBL-positive isolates.

Conclusions

This study indicates that bla_CTX-M-15 was the most prevalent β-lactamase in this region. Our study demonstrates for the first time in Palestine the identification of bla_CTX-M-15 in P. rettgeri and S. liquefaciens, also bla_CTX-M-37 in E. cloacae. The coexpression of multiple β-lactamase genes with aac(6′)-Ib-cr and qnr in the presence of ISEcp-1 and integrons in individual strains will increase the dissemination of highly resistant strains. ESBL producers were more resistant than non-ESBLs producers for almost all tested antibiotics.

Preliminary survey of extended-spectrum β-lactamases (ESBLs) in nosocomial uropathogen Klebsiella pneumoniae in north-central Iran

Infections caused by extended-spectrum β-lactamases (ESBLs) producing bacteria, including Klebsiella pneumoniae have increasingly subjected to therapeutic limitations and patients with these infections are at high risk for treatment failure, long hospital stays, high health care costs, and high mortality. The aim of this study was to screen the prevalence of the bla_TEM,bla_CTX-M and bla_SHV ESBL genes in K. pneumoniae strains isolated from nosocomial urinary tract infections (UTIs). During the March 2016 to December 2017, one hundred isolates of K. pneumoniae were collected from urine specimens of patients suffering from nosocomial UTI referred to Khatam Al-Anbia hospital in Shahrud, north-central Iran. All isolates were identified by standard bacteriological tests. The pattern of antibiotic susceptibility was determined according to the CLSI guidelines. The presence of the ESBLs was investigated using the double-disc synergy test (DDST). Polymerase chain reaction technique was used to detect the bla_TEM, bla_CTX-M and bla_SHV genes in DDST positive isolates. Most isolates showed remarkable resistance to tested antibiotics with highest rate against nitrofurantoin (75%) and trimethoprim/sulfamethoxazole (65%). The imipenem was the most effective antibiotic against K. pneumoniae isolates. ESBL phenotype was detected in 50 (50%) of isolates. The prevalence of bla_TEM, bla_CTX-M and bla_SHV genes among 50 ESBLs-positive isolates was 25 (50%), 15 (30%) and 35 (70%) respectively. The bla_TEM and bla_SHV genes were seen in 25 isolates (50%) simultaneously. The findings of this study indicated the 50% frequency rate of ESBL-producing K. pneumoniae in our geographic region. Since the treatment of infections caused by this bacterium is associated with many limitations, this high prevalence is a warning sign to adopt new control policies to prevent further spread of this microorganism.

Predominance of CTX-M Type Extended Spectrum β-lactamase (ESBL) Producers Among Clinical Isolates of Enterobacteriaceae in a Tertiary Care Hospital, Kathmandu, Nepal

Background:

ESBL problem is increasing worldwide and only limited studies on genes of ESBL are performed in Nepal.

Objectives:

We aimed to focus on the molecular detection of plasmid-mediatedblaTEM,blaSHVandblaCTX-Mgenes among the ESBL producing Enterobacteriaceae from different clinical samples.

Methods:

A total of 550 clinical samples were processed and organisms of Enterobacteriaceae were identified using standard microbiological process. ESBL producers were screened and confirmed using modified Kirby Bauer disc diffusion method by CLSI guidelines. Plasmids extracted from the confirmed ESBL positives were the template for PCR.blaSHV,blaTEMandblaCTX-Mgenes were amplified using specific primers of respective genes by uniplex PCR. The presence of these genes was confirmed by gel electrophoresis.

Results:

Among 550 different clinical samples 343 (62.36%) were culture positive. Of which, 157 (45.57%) belonged to Enterobacteriaceae.Escherichia coli(45.9%) was predominant. Of these 33.2% (52/157) isolates ESBL positive. ESBL-E. coli(52.8%) were prevalent. All ESBL positive organisms were sensitive to imipenem. Of confirmed ESBL positives, 34.6% harboringblaTEMgene, 30.8% harboringblaSHVgene andblaCTX-Mgenes were present in all ESBL producers. Twenty-eightout of 52 (53.9%) isolates harbored multipleblagenes, the most common combination beingblaCTX-M+blaTEM(21.2%).

Conclusion:

We report 100% plasmid mediated CTX-M genotype among ESBL producers which might indicate rapid dissemination ofblaCTX-Mgenes from the community to the patients. Besides, there is a need for regular monitoring of antibiotic resistance in the country and de-escalate the use of antibiotics so as to preserve the antibiotics for future generation.

Prevalence of blaCTX-M Gene among Extended-Spectrum β-Lactamases Producing Klebsiella pneumoniae Clinical Isolates in Iran: A Meta-Analysis

BACKGROUND

CTX-M-type extended-spectrum β-lactamases (ESBLs) are the most prevalent ESBLs in bacterial members of Enterobacteriaceae family including Klebsiella pneumoniae. The global spread of CTX-M-producing K. pneumoniae is a major concern in most countries including Iran. The aim of this meta-analysis was to determine the relative frequency (RF) of bla_CTX-M gene among ESBLs-producing K. pneumoniae clinical isolates in Iran and to report an overall prevalence.

METHODS

A comprehensive literature search of studies published up to July 2016 was carried out. The keywords "Enterobacteriaceae", "Klebsiella pneumoniae", "ESBLs", "CTX-M" and "Iran" were searched in PubMed, Scopus, EBSCO, Google Scholar, Scirus, SID and IranMedex in both English and Persian. Selected articles were published between July 2010 and July 2016 and all of them were in English. STATA SE version 11.0 was used for statistical analysis.

RESULTS

Twenty-four articles/abstracts were included in this analysis. Selected studies were performed in Ahvaz, Arak, Ilam, Kashan, Kerman, Mashhad, Shiraz, Tabriz, Tehran, Zabol, and Zahedan. Our pooled evidence showed that the RF of blaCTX-M gene among ESBLs-producing K. pneumoniae clinical isolates varied from 7.7% in Tabriz to 100% in Mashhad, Tehran, and Zahedan, with an overall RF of 56.7%.

CONCLUSION

Our meta-analysis revealed that the RF of CTX-M-type ESBLs-producing K. pneumoniae is diverse in different regions of Iran, and the central and eastern regions had higher prevalence rates compared to western regions.

Assessment of extended-spectrum β-lactamases and integrons among Enterobacteriaceae in device-associated infections: multicenter study in north of Iran

BACKGROUND

Device-associated nosocomial infections (DA-NIs), due to MDR Enterobacteriaceae, are a major threat to patient safety in ICUs. We investigated on Extended-spectrum β-lactamases (ESBL) producing Enterobacteriaceae and incidence of integrons in these bacteria isolated from ventilator-associated pneumonia (VAP) and catheter-associated urinary tract infections (CAUTIs) in 18 governmental hospitals in the north of Iran.

METHODS

In this cross-section study, the antibiotic susceptibility test was performed using the MIC method; also, phenotypically detection of ESBL-producing bacteria was carried out by the double-disk synergy (DDS) test. Presence of ESBL-related genes and integron Classes 1 and 2 was evaluated by the PCR method.

RESULTS

Out of a total of 205 patients with DA-NIs, Enterobacteriaceae were responsible for (72.68%) of infections. The most common DA-NIs caused by Enterobacteriaceae were VAP (77.18%), CAUTI (19.46%), and sepsis due to VAP (3.35%). The most frequently Enterobacteriaceae were; Klebsiella pneumoniae 75 (24; 32% ESBL positive), E. coli 69 (6; 8.69% ESBL positive) and Enterobacter spp. 5 (5; 100% ESBL positive). Distribution of ESBL-related genes was as follows: bla-SHV (94.3%), bla-CTX (48.6%), bla-VEB (22.9%) and bla-GES (17.14%). The incidence rate of integron class 1 and class 2 was (82.92%) and (2.9%) respectively. Eight types of ESBL-producing bacteria were observed.

CONCLUSIONS

Due to the fact that the emergence rate of ESBL Enterobacteriaceae is increasing in DA-NIs, co-incidence of different types of ESBL genes with integrons in 75-100% of strains in our study is alarming for clinicians and healthcare safety managers. Therefore, regional and local molecular level estimations of ESBLs that are agents of DA-NIs are critical for better management of empiric therapy, especially for patients in ICUs.

Aflatoxin B1 and total fumonisin contamination and their producing fungi in fresh and stored sorghum grain in East Hararghe, Ethiopia

Natural contamination of sorghum grains by aflatoxin B₁ and total fumonisin and their producing toxigenic fungi has been studied. A total of 90 sorghum grain samples were collected from small-scale farmers' threshing floors and 5-6 months later from underground pits during 2013 harvest from three districts of East Hararghe, Ethiopia. Mycotoxin analysis was done using enzyme-linked immunosorbent assay (ELISA). The limits of detection were in the range 0.01-0.03 μg kg^-1. The results revealed that all sorghum grain samples were contaminated with both Aspergillus and Fusarium species. Aflatoxin B₁ was detected at levels ranging from <LOD to 33.10 µg kg^-1 grain. There were marked variations in aflatoxin B₁ concentrations between fresh and stored samples, with much higher levels in the latter. Total fumonisin levels varied between 907 and 2041 µg kg^-1 grain across the samples. Lowest total fumonisin was recorded in freshly harvested sorghum grain samples. Sorghum is a main staple cereal in the studied districts and its consumption per day per person is high. Daily intake of low doses of mycotoxin-contaminated food stuff over a period of time could lead to chronic mycotoxicosis.

Microbe-Mediated Control of Mycotoxigenic Grain Fungi in Stored Rice with Focus on Aflatoxin Biodegradation and Biosynthesis Inhibition

Rice contaminated with fungal species during storage is not only of poor quality and low economic value, but may also have harmful effects on human and animal health. The predominant fungal species isolated from rice grains during storage belong to the genera Aspergillus and Penicillium. Some of these fungal species produce mycotoxins; they are responsible for adverse health effects in humans and animals, particularly Aspergillus flavus, which produces the extremely carcinogenic aflatoxins. Not surprisingly, there have been numerous attempts to devise safety procedure for the control of such harmful fungi and production of mycotoxins, including aflatoxins. This review provides information about fungal and mycotoxin contamination of stored rice grains, and microbe-based (biological) strategies to control grain fungi and mycotoxins. The latter will include information regarding attempts undertaken for mycotoxin (especially aflatoxin) bio-detoxification and microbial interference with the aflatoxin-biosynthetic pathway in the toxin-producing fungi.

Prevalence of CTX-M-Type and PER Extended-Spectrum β-Lactamases Among Klebsiella spp. Isolated From Clinical Specimens in the Teaching Hospital of Kashan, Iran

Background:

Extended-spectrum β-lactamases (ESBLs) is one of the most important mechanisms of resistance to β-lactams especially among Enterobacteriaceae family including Klebsiella spp. Different types of extended-spectrum β-lactamases including CTX-M-type and PER enzymes are identified among gram negative bacteria.

Objectives:

The current study aimed to determine the prevalence of CTX-M-type and PER extended-spectrum β-lactamases among Klebsiella spp. isolated from clinical specimens in the teaching hospital of Kashan, Iran.

Patients and Methods:

One hundred Klebsiella spp. were isolated from clinical specimens of hospitalized patients at Shahid-Beheshti hospital from December 2012 to November 2013. Disk diffusion method was used to determine the susceptibility of these isolates to 14 different antimicrobial agents; disks were purchased from MAST company (United Kingdom). The phenotypic double disk synergy confirmatory test was used to screen the isolates to produce extended-spectrum β-lactamase. DNAs of isolates were extracted using boiling method and PCR assay was used to characterize the bla_CTX-M type and bla_PER genes. The purified PCR products were sent to Macrogen research company (Korea) for sequencing.

Results:

Of the total 100 Klebsiella isolates, %93 was susceptible to imipenem. Resistance to ampicillin, ceftazidime, ceftriaxone, aztreonam and cefotaxime was (92%), (67%), (65%), (64%) and (59%), respectively. The phenotypic confirmatory test (PCT) confirmed that 35% (n = 35) of the isolates were ESBL-producing Klebsiella strains. The prevalence of bla_CTX-M type and bla_RER genes among Klebsiella isolates were 28% (n = 28) and 9% (n = 9), respectively.

Conclusions:

The prevalence of ESBL-producing Klebsiella strains in Shahid-Beheshti hospital in Kashan has increased. The study concluded that there was a high prevalence of the bla_CTX-M type gene among ESBL positive isolates.

Prevalence of Extended-Spectrum Beta-Lactamase-Producing Klebsiella pneumoniae Isolates in Nosocomial and Community-Acquired Urinary Tract Infections

Background

Klebsiella pneumoniae is a family member of Enterobacteriaceae. Isolates of K. pneumoniae produce enzymes that cause decomposition of third generation cephalosporins. These enzymes are known as extended-spectrum beta-lactamase (ESBL). Resistance of K. pneumoniae to beta-lactamase antibiotics is commonly mediated by beta-lactamase genes.

Objectives

The aim of this study was to identify the ESBL produced by K. pneumoniae isolates that cause community-acquired and nosocomial urinary tract infections within a one-year period (2013 to 2014) in Kashani and Hajar university hospitals of Shahrekord, Iran.

Patients and Methods

From 2013 to 2014, 150 strains of K. pneumoniae isolate from two different populations with nosocomial and community-acquired infections were collected. The strains were then investigated by double disk synergism and multiplex polymerase chain reaction (PCR).

Results

The study population of 150 patients with nosocomial and community-acquired infections were divided to two groups of 75 each. We found that 48 of the K. pneumoniae isolates in the patients with nosocomial infection and 39 isolates in those with community-acquired infections produced ESBL. The prevalence of TEM1, SHV1 and VEB1 in ESBL-producing isolates in nosocomial patients was 24%, 29.3% and 10.6%, and in community-acquired patients, 17.3%, 22.7% and 8%, respectively.

Conclusions

The prevalence of ESBL-producing K. pneumoniae isolate is of great concern; therefore, continuous investigation seems essential to monitor ESBL-producing bacteria in patients with nosocomial and community-acquired infections.

Characterization of CTX-M-Type Extend-Spectrum β-Lactamase Producing Klebsiella spp. in Kashan, Iran

CONTEXT

The CTX-M family consists of more than 50 β-lactamases, which are grouped on the basis of sequences into five subtypes including CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9 and CTX-M-25.

OBJECTIVES

The current study aimed to detect subtypes of CTX-M extended-spectrum β-lactamases (ESBLs) among ESBL positive Klebsiella isolates from patients in Kashan, Iran.

MATERIALS AND METHODS

A total of 100 clinical isolates of Klebsiella were collected and the isolates, which showed resistance or reduced susceptibility to cefotaxime, ceftazidime and/or aztreonam by the disk diffusion method were selected. These isolates were identified as ESBL-producing isolates by double disk synergy tests using clavulanic acid, cefotaxime, ceftazidime and aztreonam. The blaCTX-M type determinants were identified by the Polymerase Chain Reaction (PCR) method followed by DNA sequencing.

RESULTS

Of the 100 Klebsiella isolates, 41 (41%) demonstrated resistance or reduced susceptibility to ceftazidime and/or aztreonam and 35% (n = 35) were ESBL-producers. Twenty-eight (8o%) of the ESBL-producing isolates carried the blaCTX-M type genes. Based on PCR assays and sequencing of blaCTX-M genes, CTX-M-1, CTX-M-2 and CTX-M-9 were identified in 21 (60%), 15 (42%) and nine (34%) of these isolates, respectively (GenBank accession numbers KJ803828-KJ803829).

CONCLUSIONS

Our study showed that the frequency of blaCTX-M genes among Klebsiella isolates in our region is at an alarming rate. Also, we found a high prevalence of blaCTX-M-1 β-lactamase in Klebsiella isolates in Kashan.

Molecular characterization and in vitro susceptibilities of β-lactamase producing Escherichia coli, Klebsiella species, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus to CSE1034 and other β-lactams

OBJECTIVE

To study the prevalence of extended-spectrum β-lactamases (ESBLs) among 663 clinical isolates obtained from various parts of India and to study the occurrence of different variants of ESBLs among these isolates.

METHODS

Phenotypic characterization and susceptibility studies were performed according to the methods described in Clinical and Laboratory Standards Institute guidelines. The occurrence of ESBL variants was analyzed with PCR using the previously reported primers.

RESULTS

Among the six hundred sixty three isolates, the identified isolates were Acinetobacter baumannii (72), Escherichia coli (218), Klebsiella pneumoniae (30), Klebsiella oxytoca (63), Pseudomonas aeruginosa (264) and Staphylococcus aureus (16). PCR results revealed that approximately 89.0% of Pseudomonas aeruginosa isolates were positive for ESBL followed by Escherichia coli (85.3%), Klebsiella pneumoniae (76.6%), Klebsiella oxytoca (73.0%), Acinetobacter baumannii (72.2%) and Staphylococcus aureus (31.2%). The overall prevalence of ESBL was 82.5%. The presence of TEM type ESBLs were the predominant (in 186 isolates), followed by SHV (138), OXA (92), CTX-M (65), AmpC (33), KPC (28) and blaZ (5). Of the drugs involved in the study, CSE1034 was found to be the most efficacious against all of ESBL positive clinical isolates showing susceptibility approximately 95.7% with minimal inhibitory concentration values between 0.125 and 8.000 μg/mL for all strains tested. The susceptibilities of penems (meropenem and imipenem and cilastatin) ranged between 83% and 93% for all the isolates. The susceptibilities of other drugs like piperacillin and tazobactam, amoxicillin and clavulanic acid, cefoperazone and sulbactam were <45% for all the isolates.

CONCLUSIONS

Results of the present study indicated that majority of the isolates was susceptible to CSE1034 and it could be a potent antibacterial agent for the treatment of severe bacterial infections caused by such organisms.