Background: Acinetobacter baumannii is regarded as a significant cause of death in hospitals. The WHO recently added carbapenem-resistant Acinetobacter baumannii (CRAB) to its global pathogen priority list. There is a dearth of information on CRAB from our region. Methods: Fifty CRAB isolates were collected from four main hospitals in Bahrain for this study. Bacterial identification and antibiotic susceptibility tests were carried out using the BD Phoenix^TM and VITEK-2 compact, respectively. Using conventional PCR, these isolates were further screened for carbapenem resistance markers (bla_OXA-51, bla_OXA-23, blaO_XA-24, bla_OXA-40, bla_IMP, bla_NDM, bla_VIM, and bla_KPC). Results: All of the isolates were resistant to imipenem (100%), meropenem (98%), and cephalosporins (96–98%), followed by other commonly used antibiotics. All these isolates were least resistant to gentamicin (64%). The detection of resistance determinants showed that the majority harbored bla_OXA-51 (100%) and bla_IMP (94%), followed by bla_OXA-23 (82%), bla_OXA-24 (46%), bla_OXA-40 (14%), bla_NDM (6%), bla_VIM (2%), and bla_KPC (2%). Conclusion: The study isolates showed a high level of antibiotic resistance. Class D carbapenemases were more prevalent in our CRAB isolate collection. The resistance genes were found in various combinations. This study emphasizes the importance of strengthening surveillance and stringent infection control measures in clinical settings to prevent the emergence and further spread of such isolates.

Context: Fluoroquinolones are the most effective antibiotics against Pseudomonas aeruginosa; many strains, however, have shown resistance due to mutations in DNA gyrase, topoisomerase IV, or in the efflux pumps. Little is known about P. aeruginosa efflux pump resistance mechanisms in the Kingdom of Bahrain. Aim: The aim was to study efflux pump-mediated fluoroquinolone resistance among P. aeruginosa isolates using phenotypic (E-test and agar dilution) and genotypic (real-time-polymerase chain reaction [RT-PCR]) methods. Materials and Methods: Fifty ciprofloxacin-resistant P. aeruginosa isolates were included in this study. Genus and species of P. aeruginosa were confirmed by conventional PCR. The minimum inhibitory concentration (MIC) of ciprofloxacin with and without carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was determined by E-test and agar dilution test. The overexpression of genes MexB, MexD, MexF, and MexY was measured by RT-PCR. Results: All isolates were confirmed as P. aeruginosa. Among the fifty isolates, four showed reduction in ciprofloxacin MIC after addition of CCCP. These four isolates showed upregulation of expression of at least one of the four genes by RT-PCR. The mean gene expression of MexB, MexD, MexF, and MexY increased by 1.6, 4.65, 3.4, and 3.68-fold, respectively. Conclusion: The results demonstrate the presence and type of efflux pump overexpression, mandating for large multicentric studies.

INTRODUCTION: Carbapenem-resistant Pseudomonas aeruginosa has emerged as a life-threatening infectious agent worldwide. Carbapenemase genes are reported to be some of the most common mechanisms for carbapenem resistance in P. aeruginosa. No reports are available from the Kingdom of Bahrain about carbapenem resistance and the underlying cause. In this study, we determined to study the presence of the metallo-beta-lactamase (M β L) genes of VIM family and NDM-1 in carbapenem-resistant P. aeruginosa strains. METHODOLOGY: Fifty carbapenem-resistant P. aeruginosa isolates were obtained from three main hospitals of Bahrain. They were subjected to antimicrobial susceptibility testing by disc diffusion test. Subsequently, MβL was detected by imipenem-ethylene diamine tetraacetic acid (EDTA) combined disc test and conventional polymerase chain reaction. RESULTS: Among 50 P. aeruginosa strains, 40 (80%) were imipenem resistant. Among the 40 imipenem-resistant strains, 35 (87.5%) strains were positive for the imipenem-EDTA combined disc test, and 21 (52%) were carrying MβL genes. Nineteen (47.5%) strains were positive for the VIM gene; one (2.5%) strain was carrying the NDM-1 gene, while one strain was carrying both the VIM and NDM-1 genes. None of the imipenem sensitive strains carried the VIM or NDM-1 gene. CONCLUSION: This is the first study to report the presence of the VIM family gene and NDM-1 genes in imipenem-resistant P. aeruginosa isolates in the Kingdom of Bahrain. The study also confirms the multiple drug resistance by the MβL strains, attention should therefore from now on, be focused on prevention of further spread of such isolates by firm infection control measures, and to reduce its threat to public health.

The emergence of extended-spectrum β-lactamase-producing Klebsiella pneumoniae, including CRKP infections, has resulted in significant morbidity and mortality worldwide. We aimed to explore the presence of bla genes (CTX-M, TEM, and SHV) in CRKP isolates. A total of 24 CRKP isolates were randomly selected from the Salmaniya Medical Complex Microbiology Laboratory. These isolates, which were positive for carbapenemases, were further explored for CTX-M, TEM, and SHV genes using PCR. All the CTX-M PCR amplicons were sent for sequencing. To determine genetic relatedness, molecular typing by ERIC-PCR was performed. The bla gene testing demonstrated that a significant proportion of these isolates harbored SHV, CTX-M, and TEM genes (100%, 91.6%, and 45.8%), respectively. Bioinformatic analyses confirmed CTX-M-15 in these isolates. ERIC-PCR analysis showed three clusters demonstrating genetic relatedness. The study findings reveal the concomitant carriage of the SHV and CTX-M-15 and a comparatively lower carriage of TEM genes in CRKP isolates. Our findings highlight the significance of routinely reporting the presence of antibiotic resistance genes along with regular antibiotic sensitivity reports, as this will aid clinicians in prescribing appropriate antibiotics.

Objectives AmpC β-lactamases are cephalosporinases that confer resistance to cephalothin, cefazolin, cefoxitin, penicillin, and β-lactamase inhibitor-β-lactam combinations. Even though the AmpC resistance is reported, but the accurate occurrence of AmpC β-lactamases in Enterobacteriaceae members is still unknown. Techniques to identify AmpC producers are still evolving but not yet optimized for the clinical laboratory. Here we aimed to compare the test performance of two different phenotypic methods, that is inhibitor-based assay using boronic acid and disk approximation test for AmpC detection in Enterobacteriaceae isolates from a tertiary hospital microbiology laboratory. Materials and Methods The study includes 137 nonrepeat Enterobacteriaceae strains. Bacterial isolates, that yielded a zone diameter of less than 18 mm for cefoxitin by disk diffusion method were considered potential AmpC producers and further confirmed by phenotype methods—inhibitor-based assay using boronic acid and disk approximation test. A multiplex polymerase chain reaction was used to detect the most common plasmid-mediated AmpC genes: ACC, FOX, MOX, DHA, CIT, and EBC. Results Of the 137 clinical isolates, 58 (42.33%) were cefoxitin resistant, while 53.4 and 18.9% of the cefoxitin-resistant isolates were positive by inhibitor-based assay and disk approximation test. Multiplex PCR detected 42 (30.6%) isolates with AmpC genes. Of the 42 isolates, the inhibitor-based assay detected 25 (59.5%) isolates, while the disk approximation test detected nine (21.4%) isolates. Conclusion Our findings suggest that inhibitor-based assay using boronic acid can be used for the detection of the isolates that harbor AmpC β-lactamases. This method is cost-effective, simple to perform, and easy to interpret. Thus AmpC detection as a routine in clinical laboratories can help in appropriate therapeutic intervention and improved infection control.

BACKGROUND: Enterobacteriaceae with AmpC β-lactamase are multidrug-resistant organisms and represent a significant challenge to patient care. This study aims to determine the prevalence of plasmid-derived AmpC β-lactamase among extended spectrum β-lactamases (ESBL)-producing Enterobacteriaceae strains in Bahrain. METHODS: It was a cross-sectional study. A total of 185 ESBL-producing Enterobacteriaceae isolates were recovered from clinically significant specimens from January 2018 to December 2019. The samples underwent initial screen for cefoxitin resistance by disc diffusion test and subsequent phenotypic confirmation of AmpC production with phenyl boronic acid assays as well as genotypic analysis by multiplex polymerase chain reactions for AmpC subtypes. Drug-resistant features of these clinical isolates were also examined. RESULTS: Twenty-nine ESBL-producing Enterobacteriaceae isolates were cefoxitin resistant. Phenotypic and genotypic analyses confirmed that 8 and 12 cefoxitin-resistant isolates are AmpC positive, respectively. These AmpC producers are multidrug resistant, and Escherichia coli is the dominant strain among them. CONCLUSIONS: Plasmid-mediated spread of AmpC is present in clinically relevant Enterobacteriaceae species in Bahrain. Rational antimicrobial therapy against these multidrug-resistant organisms and continued surveillance of antimicrobial resistance mechanisms among the clinical isolates are recommended for optimal patient care.