Pseudomonas aeruginosa are capable of causing infection in individuals that are immunocompromised, most of whom are on admission in hospitals [1]. It is a general observation that the occurrence by sites of nosocomial infections (NIs), reveal urinary site as the most prevalent, followed by surgical wound sites.2 Nosocomial infections due to multidrug resistance (MDR) P. aeruginosa are a critical health problem to hospitalized patients [19].
In this study, the prevalence rates of P. aeruginosa in urine and wounds sites were 16% and 19%, respectively, which was in conformity with the 16% rate for urine reported in a study in Iran, which also recorded a relatively higher rate of 33% for wounds [20]. However, a lower prevalence rate of 9% for wound infections was reported in another study in Nigeria [21].
Incidentally more males than female participants were admitted into this study; however, while P. aeruginosa caused more nosocomial wound infections in males 11(18%), more females 9 (23.7%), had nosocomial urinary tract infections (UTIs). Also, P. aeruginosa was found to cause more nosocomial UTIs in the 37–48 years (mean = 42.5 years) age group across both genders; those whose ages were above 48 years had more wound infections caused by the bacteria. This agrees with the result of another study that found more nosocomial infections in males rather than females, though among the 51 years and above age group [19].
Multidrug resistance displayed by the P. aeruginosa isolates from both urine and wound samples from the participants involved the commonly used antibiotics such as Gentamicin and Ciprofloxacin and even the reserved antibiotics in the study area such as Meropenem and Piperacillin-Tazobactam. As revealed by this study, P. aeruginosa isolates showed least resistance to Ceftazidime antibiotic in urine, 4 (25%) and wounds, 6 (31.6%). This is in contrast to reports of higher resistance from various studies, including reports with a ceftazidime resistance rate of 100% in Ethiopia [19], 69% in Uganda [22], 77.7% in India [23] and 72.4% in Vietnam [24]. The reason for this observation is not obvious, especially as there is no antibiotic policy and no mechanisms for controlling antimicrobial usage in Akwa Ibom State as well as Nigeria. Interestingly, the revealed resistance of the bacteria to the commonly used Gentamicin and Ciprofloxacin antibiotics in the study area due to their availability and affordability ranges from 50 to 57.9%, and 31.3 to 42.1%, respectively. A relatively similar result for Gentamicin-resistance and Ciprofloxacin-resistance P. aeruginosa were recorded in North East Ethiopia and Iran [25, 26], respectively, even as higher rates have been reported for Gentamicin in Uganda [22]. The 50–63.1% rate of Meropenem-resistant P. aeruginosa is rather worrisome, especially as the drug is supposed to be reserved, not readily available and affordable in the study area. However, this is possibly so because of its prescription by health personnel for empirical treatment without recourse to antibiotic sensitivity testing. This is in contrast to the 16.7% Meropenem resistance rates by the same organism reported by some studies [25], even as rates as high as 86% have been previously reported in Vietnam.[27]. In this present study, the highest rates of 52.6–75% resistance of P. aeruginosa isolates in wounds and urine, were found to be against Piperacillin-Tazobactam antibiotic, another drug not readily available but not protected because of lack of policy. This is however in concordance with the > 73% rates reported by another study [25]. A low proportion of P. aeruginosa isolates 15.8–18.8%, in the study were susceptible Cefepime, a frequently used anti-pseudomonas fourth generation cephalosporin. A study in India also reported high resistance rate (71.7%), by the bacteria to Cefepime [28].
In this study, the detectable antibiotic resistance genes among the P. aeruginosa strains were QnrB, GMr, AmpC, and VIM. This differs from the report of study by Butiuc-Keul et al (2021), where only AmpC gene was detected in the isolates [29]. Incidentally, the AmpC genes were detected in 3 of the P. aeruginosa strains in our study, indicating the involvement of this gene in causing antibiotic resistance, especially against beta-lactam class of antibiotics. The VIM gene, a metallo betalactamase prevalent globally, was detected in 1 (10%) of the isolates, this is in contrast to the 58.7% reported by a study in Iran [30]. This P. aeruginosa isolate with VIM gene from urine was also found to harbour the AmpC and QnrB genes which explains further the multiple drug resistance treatment failure outcomes experienced in the study area.
In conclusion, the prevalence of P. aeruginosa strains causing nosocomial infections of urinary and wounds sites were 16% and 19%, respectively. But while P. aeruginosa caused more nosocomial wound infections in males 11(18%), more females 9 (23.7%), had nosocomial urinary tract infections (UTIs). This study revealed high rates of resistance (52.6–75%) of P. aeruginosa isolates to Piperacillin-Tazobactam antibiotic, a drug not readily available and usually prescribed, though not protected because of a lack of policy in the area. Finally, the detectable antibiotic resistance genes among the P. aeruginosa strains were QnrB, GMr, AmpC, and VIM, portending multidrug resistance and treatment failure outcomes.