# Investigation of Bacterial Infections and Antibiotic Resistance Patterns Among Clinical Isolates in the Center of Iran

## TL;DR

This study analyzed bacterial infections and antibiotic resistance in clinical isolates from a hospital in Iran, highlighting high resistance rates and the presence of specific resistance genes.

## Contribution

The study provides new insights into the prevalence of specific antibiotic resistance genes and resistance patterns in clinical isolates from a specific region in Iran.

## Key findings

- Escherichia coli was the most common isolate, followed by Klebsiella spp. and Staphylococcus aureus.
- High resistance rates were observed to erythromycin, penicillin, cefixime, and trimethoprim–sulfamethoxazole.
- Among Gram-negative isolates, 22.89% were ESBL-positive, with high prevalence of blaSHV and blaPER2 genes.

## Abstract

Introduction: Bacterial infection is a considerable problem in hospitals. Thus, this study was executed to appraise the rampancy of bacterial infections, antimicrobial susceptibility patterns, and molecular characterization of isolates among patients in Bafgh Hospital in Yazd, Iran, in 2020.

Methods: In the current study, we surveyed 103 isolates of 400 clinical specimens from early March 2020 to September 2020 in Bafgh Hospital. We assessed phenotypic traits and antibiotic resistance with standard microbiological methods. Phenotypic methods were also performed to identify extended-spectrum beta-lactamases (ESBLs) in Gram-negative bacilli, inducible clindamycin resistance, and methicillin resistance in Staphylococcus according to CLSI guidelines. Molecular identification of isolates was done by conventional PCR 16S rRNA gene sequencing. Furthermore, we investigated the prevalence of resistant genes including blaTEM, blaPER-2, blaCTX-M, blaSHV, and blaVEB-1 in Gram-negative bacteria and the mecA gene in staphylococcal species.

Results: From 400 different clinical specimens, 103 isolates of Gram-positive and Gram-negative bacteria were isolated. Based on phenotypic and molecular methods, most common isolates were Escherichia coli (53 isolates), followed by Klebsiella spp. (18 isolates), and Staphylococcus aureus (16 isolates). The highest resistance was found in Gram-positive bacteria to erythromycin (66.67%) and penicillin (55.56%), while considering Gram-negative bacteria, the most resistant was cefixime (49.41%) and trimethoprim–sulfamethoxazole (47.05%). In addition, out of 16 S. aureus isolates, 62.5% and 17.65% were resistant to methicillin and clindamycin, respectively. Among 83 Gram-negative isolates, 22.89% were ESBL-positive. The prevalence of blaSHV, blaPER2, blaTEM, blaCTX-M, and blaVEB-1 genes was 78.31%, 59.03%, 40.96%, 30.12%, and 0%, respectively.

Conclusions: The outbreak of bacterial infections is relatively high in hospitals. Recognizing risk agents for bacterial infections and restricting the administration of multidrug-resistant antibiotics is a substantial measure that must be taken to prevent patient mortality.