Emergence of bla TEM, bla CTX-M, bla SHV and bla OXA genes in multidrug-resistant Enterobacteriaceae and Acinetobacter baumannii in Saudi Arabia

Molecular characterization of carbapenemase and extended spectrum beta-lactamase producing Acinetobacter baumannii isolates causing surgical site infections in Ethiopia

BACKGROUND

Acinetobacter baumannii is an opportunistic pathogen that can cause a variety of nosocomial infections in humans. This study aimed to molecularly characterize extended-spectrum beta-lactamase (ESBL) producing and carbapenem-resistant Acinetobacter species isolated from surgical site infections (SSI).

METHODS

A multicentre cross-sectional study was performed among SSI patients at four hospitals located in Northern, Southern, Southwest, and Central parts of Ethiopia. The isolates were identified by microbiological methods and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility was determined using disk diffusion. The presence of phenotypic ESBL and carbapenemase production was detected by employing standard microbiological tests, including combined disk diffusion (CDT). ESBL and carbapenem resistance determinants genes were studied by polymerase chain reaction (PCR) and sequencing.

RESULTS

A total of 8.7% Acinetobacter species were identified from 493 culture-positive isolates out of 752 SSI wounds. The species identified by MALDI-TOF MS were 88.4% A. baumannii, 4.7% Acinetobacter pittii, 4.7% Acinetobacter soli, and 2.3% Acinetobacter lactucae. Of all isolates 93% were positive for ESBL enzymes according to the CDT. Using whole genome sequencing 62.8% of the A. baumannii harbored one or more beta-lactamase genes, and 46.5% harbored one or more carbapenemase producing genes. The distribution of beta-lactamases among Acinetobacter species by hospitals was 53.8%, 64.3%, 75%, and 75% at JUSH, TASH, DTCSH, and HUCSH respectively. Among ESBL genes, blaCTX-M alleles were detected in 21.4% of isolates; of these 83.3% were blaCTX-M-15. The predominant carbapenemase gene of blaOXA type was detected in 24 carbapenem-resistant A. baumannii followed by blaNDM alleles carried in 12 A. baumannii with blaNDM-1 as the most common.

CONCLUSIONS

The frequency of Acinetobacter species that produce metallobetalactamases (MBLs) and ESBLs that were found in this study is extremely scary and calls for strict infection prevention and control procedures in health facilities helps to set effective antibiotics stewardship.

Antibiotic Resistance Trends Among Enterobacteriaceae in Saudi Arabia: A Systematic Review

Antibiotic resistance is a global public health concern that poses a significant threat to the effective treatment of bacterial infections. Enterobacteriaceae, a family of gram-negative bacteria, are associated with a wide range of infections, including urinary tract infections, bloodstream infections, and respiratory tract infections. This systematic review aimed to examine the antibiotic resistance trend among Enterobacteriaceae in Saudi Arabia in the period between 2003 and 2023. Five databases (PubMed, Medline, Ovid, Scopus, and Cochrane) were searched using the keywords "Resistance AND Enterobacteriaceae AND Saudi Arabia" in the title and abstract. All papers assessing the prevalence of resistance among Enterobacteriaceae in Saudi Arabia were included in the systematic review. Out of 97 papers that were extracted through the database search, 22 articles were considered suitable for the systematic review. The articles included 17027 Enterobacteriaceae isolates, out of which 7592 isolates were identified as resistant bacteria. The studies included various resistant strains, such as Escherichia coli and Klebsiella pneumoniae, that were responsible for various clinical conditions, including urinary tract infections, blood infections, surgical site infections, and pneumonia. In addition, the review highlighted the dynamic nature of antibiotic resistance, with the identification of new resistant bacterial species and the emergence of resistance to newer antibiotic classes over the last decade. Continued surveillance, rational antibiotic use, and the development of alternative treatment options are crucial to address the evolving landscape of antibiotic resistance among Enterobacteriaceae bacteria in the country.

Assessment of BlaTEM, BlaSHV, and BlaCTX-M genes of antibiotic resistance in Gram-negative bacilli causing urinary tract infections in Khartoum State: a cross-sectional study

BACKGROUND

Gram-negative bacilli are the most common etiological agents responsible for urinary tract infections. The prevalence of antibiotic resistance in Gram-negative bacilli is increasing at a rapid pace globally, which is constraining the available choices for UTI treatment. The objectives of this study are to identify the most common causal organisms of urinary tract infections (UTIs), and to determine their drug resistance patterns.

MATERIALS AND METHODS

This was a cross-sectional hospital-based study conducted at El-Amal Hospital, Bahri Teaching Hospital, and Al-Baraha Hospital, Khartoum State, from March to October 2022. Urine samples from patients suspected to have UTI were collected, and patients with confirmed UTI by laboratory investigations and yielded culture growth were enrolled. Antibiotic sensitivity testing and PCR testing of the blaTEM, blaSHV, and blaCTX-M genes were done.

RESULTS

This study included 50 patients with UTI out of 229 suspected patients (21.8%). The most prominent group of patients was older than 60 years (40%); the majority were females (70%). Escherichia coli was the most prevalent isolated organism (50%), followed by Klebsiella oxytoca (24%), Klebsiella pneumoniae (20%), Pseudomonas aeruginosa (4%), and Citrobacter freundii (2%). A small percentage of organisms were resistant to colistin (17%). However, 77% were resistant to amikacin, 97.6% to cefotaxime, 96.8% to ceftazidime, 97.6% to ceftriaxone, 96.8% to cefixime, 87.6% to ciprofloxacin, 88.4% to gentamycin, 62% to imipenem, 67.6% to meropenem, 87.6% to norfloxacin, and 95.6% to trimethoprim. The overall resistance of isolated gram-negative organisms was 81%. The most prevalent gene for the resistance was blaTEM (100%), followed by blaCTX-M (94%), and then blaSHV (84%).

CONCLUSION

Escherichia coli and Klebsiella species were the most commonly isolated uropathogens in this study, and the majority were highly resistant to most of the antimicrobial agents tested. Resistance genes blaTEM, blaCTX-M, and blaSHV are very common in uropathogens.

Outbreak of Multidrug-resistant Acinetobacter baumannii in a Tertiary Health Center from Northwestern Nigeria

Background

In spite of its global notoriety and WHO alarm, Acinetobacter baumannii is still an understudied critical-priority pathobiont in Nigeria. We characterized its antimicrobial susceptibility profile and resistance genes during an outbreak.

Materials and Methods

This cross-sectional study involved collection of patients' urine samples and swabs from unit staff's hands and ward environments for the identification of A. baumannii strains using standard morphologic and biochemical methods. The disk diffusion method was used to assess the antimicrobial susceptibility profile of the isolates with the production of extended-spectrum beta-lactamases (ESBLs) confirmed by the combined disk test screening method. Characterization of the resistance genes of the ESBL producers was carried out using polymerase chain reaction polymerase chain reaction technique.

Results

A.

total of eight (six clinical and two nonclinical) A. baumannii isolates were identified. The overall isolate susceptibility and resistance rates to all the antimicrobial agents was 56.3% (27/48) and 35.4% (17/48), respectively. Similarly, all (8/8; 100.00%) isolates were susceptible to meropenem and 75.0% (6/8) to ampicillin-sulbactam while 62.5% (5/8) were resistant to trimethoprim-sulfamethoxazole and 50.0% (4/8) to each of ciprofloxacin and ceftazidime. In addition, 37.5% (3/8) of the isolates were multidrug resistant (MDR) with nonclinical isolates exhibiting more antimicrobial resistance than their clinical counterparts (9/12%-75.0% vs. 8/36%-22.2%). Phenotypic detection and molecular characterization revealed three ESBL-producing isolates that each harbored blaSHV and blaTEM genes with blaCTX-M gene being absent.

Conclusion

MDR strains of A. baumannii harboring blaSHV and blaTEM genes were recovered from clinical and environmental sources during the outbreak, which was contained with preventive measures recommended.

Prevalence and characterization of antimicrobial-resistant Escherichia coli isolated from veterinary staff, pets, and pet owners in Thailand

BACKGROUND

Companion animals may act as antimicrobial resistance (AMR) reservoirs. This study investigated the prevalence and AMR patterns of Escherichia coli in pets and people in close contact with pets.

METHODS

A total of 955 samples were collected from veterinary clinics across Thailand by rectal and skin or ear swabs from dogs and cats and fecal swabs from veterinarians, veterinary assistants, and pet owners. The minimum inhibitory concentrations (MICs) of the obtained isolates were investigated using Sensititre™ MIC plates against 21 different antimicrobial drugs.

RESULTS

Escherichia coli from pets was frequently resistant to ampicillin (100%) and amoxicillin-clavulanic acid (100%), whereas E. coli from pet owners, veterinarians, and veterinary assistants was mostly resistant to tetracycline. The multiple antibiotic resistance index revealed that multidrug-resistant E. coli isolates were frequently found in dogs (34.92%), cats (62.12%), veterinarians (61.11%), veterinarian assistants (36.36%), and pet owners (47.62%). The most common AMR genes identified in this study were blaCTX-M, blaTEM, tetA, and tetB, which were associated with the antimicrobial susceptibility results. Additionally, extended-spectrum beta-lactamase (ESBL)-associated genes (i.e., blaCTX-M, blaTEM, and blaSHV) were found in 21.69%, 71.97%, 27.78%, and 21.43% of E. coli isolated from dogs, cats, veterinarians, and pet owners, respectively.

CONCLUSIONS

Our findings demonstrated the presence of AMR genes, particularly ESBL-associated genes, in E. coli isolated from healthy pets and veterinarians. This implies that these sources of E. coli could potentially be reservoirs for antibiotic resistance, thereby increasing the risk of harm to both humans and animals. These findings highlight the importance of implementing effective AMR control measures in veterinary practices, as bacteria resistant to commonly used antimicrobials are present in humans and animals.

Emergence of NDM-1-producing Raoultella ornithinolytica from reservoir water in Northeast Thailand

Background and Aim

Antibiotic resistance is a major global health threat. The increasing prevalence of drug-resistant bacteria poses a serious challenge to the effective treatment of infections in both humans and animals. Water is a major source of human and animal exposure to bacteria, and the presence of drug-resistant bacteria in water could present a severe threat to public health and animal production. This study investigated the presence of drug-resistant bacteria in Lam Pao Dam (LPD) water in Kalasin, Thailand.

Materials and Methods

Ampicillin-resistant strains were obtained from LPD water and identified using 16s rDNA sequencing. Antibiotic resistance genes were detected by polymerase chain reaction using specific primers. The presence of antibiotic-resistant bacteria was evaluated using 16s amplicon analysis. The minimum inhibitory concentration (MIC) of Raoultella ornithinolytica strains against antibiotics was determined.

Results

A total of 12 R. ornithinolytica, 4 Bacillus cereus, and 4 Enterococcus faecalis isolates were resistant to ampicillin. Almost all R. ornithinolytica strains harbored blaSHV and blaOXA genes, and two strains also harbored the blaNDM-1 gene. All four E. faecalis strains harbored the blaIMP gene. The most abundant species in the LPD sample was Exiguobacterium indicum, followed by E. faecalis and R. ornithinolytica. The MICs of 10 R. ornithinolytica strains against five antibiotics revealed that all strains were resistant to ampicillin but susceptible to meropenem, doripenem, ertapenem, and imipenem.

Conclusion

These findings suggest a high prevalence of drug-resistant bacteria in LPD water. This is a cause for concern, as it could spread antibiotic-resistant infections in the community.

The Characteristics of Extended-Spectrum β-Lactamases (ESBLs)-Producing Escherichia coli in Bloodstream Infection

Background

Bloodstream infection (BSI) is a common type of infection frequently diagnosed in clinics. The emergence and spread of ESBLs-producing Escherichia coli (E. coli) has emerged as one of the biggest challenges in global community health.

Methods

The production of ESBLs was determined by the composite disk diffusion method. The expression of the various resistance and virulence genes were detected by PCR and sequencing. Multi-locus sequence typing (MLST) and phylogenetic groups were used for the classification. The transfer of resistant plasmids was determined by conjugation assay. The statistical differences were analyzed using Statistical Product and Service Solutions (SPSS) version 23.0.

Results

A total of 60 strains of ESBLs-producing E. coli were collected. The resistance genes that were identified included bla _CTX-M, bla _TEM, bla _SHV, bla _OXA-1 and mcr-1. The most common one was the bla _CTX-M including bla _CTX-M-27 (n = 16), bla _CTX-M-14 (n = 15), bla _CTX-M-15 (n = 11), bla _CTX-M-55 (n = 14) and bla _CTX-M-65 (n = 5). A total of 31 STs were detected, and the most abundant among which was ST131 (n = 16, 26.7%). Most of the E. coli (n = 46, 76.7%) belonged to the groups B2 and D. And some virulence genes were related to the classification of the E. coli. Among them, the detection rates of hek/hra, kpsMII and papGII-III in groups B2 and D were higher than those in groups A and B1. The detection rates of cnf1, iucC and papGII-III in ST131 were higher than those in non-ST131. And the distributions of hek/hra, iroN, iucC, kpsMII and papGII-III were related to the bla _CTX-M subtypes. Finally, most bacterial (n = 32, 53.3%) resistance genes could be transferred between the bacteria by plasmids, especially IncFIB.

Conclusion

ESBLs-producing E. coli in BSI exhibited had high resistance rates and carried a variety of virulence factors (VFs). This is necessary to strengthen the monitoring of ESBLs-producing isolates in the medical environment.

“Biofilm Formationand Antibiotic Resistance Profiles of Water-borne Pathogens

Water sources (surface water, drinking water, rivers, and ponds) are significant reservoirs for transmitting antibiotic-resistant bacteria. In addition, these waters are an important public health problem because they are suitable environments for transferring antibiotic resistance genes between bacterial species. Our study aimed to assess the prevalence of Extended-spectrum beta-lactamase (ESBL) producing isolates in water samples, the susceptibility of the isolates to the specified antibiotics, the determination of biofilm ability, antibiotic resistance genes, and the molecular typing of the isolates. For this purpose, Polymerase chain reaction (PCR) and Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) analyses were used. Out of 70 isolates, 15 (21%) were ESBL producing, and sent for the MALDI-TOF analysis, where Escherichia coli, Acinetobacter calcoaceticus, Enterobacter bugandensis, Acinetobacter pittii, Pseudomonas aeruginosa, Acinetobacter junii, Pseudomonas oleovorans, and Enterobacter ludwigigii were identified. Moreover, colistin resistance genes (mcr1/2/6, mcr 4, mcr 5, mcr 3/7, and mcr 8), ESBL-encoding genes(bla_SHV, bla_TEM, and bla_CTX-M) and carbapenemase genes (bla_NDM, bla_OXA-48, and bla_KPC) using molecular analysis (PCR) were confirmed. The colistin resistance gene was detected at 80% (12/15) in the isolates obtained. The distribution of these isolates according to resistance genes was found as mcr 1/2/6 4 (20%), mcr3/7 3 (13%), and mcr 5 (40%). Additionally, the isolates harbored bla_SHV(6.6%) and bla_TEM (6.6%) genes. However, bla_NDM, bla_OXA-48, bla_KPC, and bla_CTX-M genes were not detected in any isolates. According to the Congo red agar method, seven (46.6%) isolates showed negative biofilm ability, and eight (53.3%) showed moderate biofilm ability. However, the microplate method detected weak biofilm in 53.3% of the isolates.In conclusion, this study provides evidence for the existence of multidrug-resistant bacteria that co-exist with mcr and ESBL genes in water sources. These bacteria can migrate to other environments and pose increasing threats to public health.

Molecular Epidemiology of Carbapenem-Resistant K. pneumoniae Clinical Isolates from the Adult Patients with Comorbidities in a Tertiary Hospital, Southern Saudi Arabia

Hospitalized patients are likely to have chronic illnesses and are at an increased risk of mortality due to infection caused by MDR bacteria. We aimed to identify carbapenem-resistant genes carrying Klebsiella pneumoniae (K. pneumoniae) isolates and their risk factors recovered from adult patients with comorbidities. A cross-sectional study was carried out between April 2021 and December 2021 at King Abdullah Hospital (KAH) in Bisha province, Saudi Arabia. Seventy-one multi-drug resistant K. pneumoniae recovered from clinical samples and screened for carbapenemase genes of blaOXA-48-like, blaNDM-1, blaKPC, blaVIM, and blaIMP. Of 71 MDR K. pneumoniae examined, 47 (66.2%) isolates harbored various carbapenemase genes. The most prevalent single resistance gene was blaOXA-48-like (62.5%; n = 25), and 33.3% of them were recovered from sputum isolates. The blaNDM-1 gene was detected in 12 (30.0%) isolates, and eight of them were recovered from urine (n = 4) and blood (n = 4). Two (5.0%) single blaKPC genes were recovered from the sputum (n = 1) and blood (n = 1) isolates. In contrast, no blaIMP- and blaVIM-carrying isolates were detected. The co-existence of two resistance genes between blaOXA-48-like and blaNDM-1 was found in six strains, whereas only one strain was found to be produced in the three genes of blaNDM-1, blaKPC, and blaOXA-48-like. There were statistically significant associations between the presence of carbapenem-gene-carrying K. pneumoniae and patients' gender (χ2(1) = 5.94, p = 0.015), intensive care unit admission (χ2(1) = 7.649, p = 0.002), and chronic obstructive pulmonary disease (χ2(1) = 4.851, p = 0.028). The study highlighted the existence of carbapenemase-producing K. pneumoniae, particularly blaOXA-48-like and blaNDM-1, in patients with comorbidities. Our findings emphasize the importance of the molecular characterization of resistance-determinant-carrying bacterial pathogens as a part of infection control and prevention in hospital settings.

Extended Spectrum- and Carbapenemase-Based β-Lactam Resistance in the Arabian Peninsula—A Descriptive Review of Recent Years

Antimicrobial resistance (AMR) is a global problem that also includes countries of the Arabian Peninsula. Of particular concern, is the continuing development of extended-spectrum β-lactamases (ESBLs) in the countries of this region. Additionally, antibiotic treatment options for ESBL-producing bacteria are becoming limited, primarily due to the continuing development of carbapenem resistance (CR), carbapenems being frequently used to treat such infections. An overview of recent publications (2018–2021) indicates the presence of ESBL and/or CR in patients and hospitals in most countries of the Arabian Peninsula, although the delay between microbial isolation and publication inevitably makes an accurate analysis of the current situation rather difficult. However, there appears to be greater emphasis on CR (including combined ESBL and CR) in recent publications. Furthermore, although publications from Saudi Arabia are the most prevalent, this may simply reflect the increased interest in ESBL and CR within the country. Enhanced ESBL/CR surveillance is recommended for all countries in the Arabian Peninsula.